WO2012098773A1 - Transmission control device for continuously variable transmission - Google Patents

Transmission control device for continuously variable transmission Download PDF

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Publication number
WO2012098773A1
WO2012098773A1 PCT/JP2011/077981 JP2011077981W WO2012098773A1 WO 2012098773 A1 WO2012098773 A1 WO 2012098773A1 JP 2011077981 W JP2011077981 W JP 2011077981W WO 2012098773 A1 WO2012098773 A1 WO 2012098773A1
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WO
WIPO (PCT)
Prior art keywords
thrust
gear ratio
transmission
target
primary
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PCT/JP2011/077981
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French (fr)
Japanese (ja)
Inventor
啓太 奥平
古閑　雅人
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日産自動車株式会社
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Application filed by 日産自動車株式会社 filed Critical 日産自動車株式会社
Publication of WO2012098773A1 publication Critical patent/WO2012098773A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
    • F16H61/662—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members
    • F16H61/66254—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members controlling of shifting being influenced by a signal derived from the engine and the main coupling
    • F16H61/66259—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members controlling of shifting being influenced by a signal derived from the engine and the main coupling using electrical or electronical sensing or control means

Definitions

  • This invention relates to a device for controlling the shift of a continuously variable transmission.
  • a continuously variable transmission (Continuously Variable Transmission; hereinafter referred to as "CVT” as appropriate) comprising a primary pulley provided on the input shaft, a secondary pulley provided on the output shaft, and an endless torque transmission member stretched around these pulleys Is known.
  • the primary pulley includes a fixed sheave and a movable sheave.
  • the secondary pulley also includes a fixed sheave and a movable sheave.
  • the gear ratio When the gear ratio is controlled, first, the accelerator pedal operation amount and the vehicle speed are applied to the shift characteristic map, and the target rotational speed of the primary pulley is set. Next, a target gear ratio for realizing this target rotation speed is set. Then, the movable sheave of the primary pulley is moved in the axial direction so that this target gear ratio is realized. In accordance with this, the secondary pulley tightens the endless torque transmission member with a predetermined thrust so that the endless torque transmission member does not slip. By doing in this way, the winding diameter of an endless torque transmission member changes and the gear ratio is controlled steplessly.
  • the chain belt has a large number of blocks connected in a ring via links and pins.
  • the primary pulley pulls the chain belt.
  • the secondary pulley is rotationally driven.
  • the chain belt may be elastically deformed and stretched by a pulling force. If this elongation is not taken into account, a response delay of the shift control occurs.
  • the target gear ratio is set to the minimum value, that is, the vehicle travels in an overdrive state.
  • the chain belt endless torque transmission member
  • the winding diameter of the secondary pulley increases in accordance with the amount of extension.
  • the actual gear ratio changes to the low side from the target gear ratio.
  • the target speed ratio ascertained by the control unit is different from the actual speed ratio of the continuously variable transmission.
  • the control unit tries to bring the actual speed ratio closer to the target speed ratio by feedback control.
  • the control unit continues to perform feedback control. Then, the feedback value is accumulated on the upshift side.
  • the target gear ratio is limited to a realizable range according to the input torque.
  • An object of the present invention is to provide a transmission control device for a continuously variable transmission that can prevent a target transmission gear ratio from being unnecessarily limited and an actual transmission gear ratio range from being unduly narrowed.
  • a shift control device for a continuously variable transmission shifts between the pair of pulleys via an endless torque transmission member wound around the pair of pulleys. Then, a target speed ratio limit value is calculated based on a target speed ratio calculation unit that calculates the target speed ratio of the transmission, at least one of pulley thrust and pulley rotation speed, and torque input to the transmission. If the limit value calculation unit to calculate and the target gear ratio calculation value calculated by the target gear ratio calculation unit exceed the limit value, the limit value is set as the target gear ratio, and the target gear ratio calculation value is If it does not exceed the value, a target gear ratio setting unit that sets the target gear ratio calculated value as the target gear ratio is provided.
  • FIG. 1 is a schematic configuration diagram showing a first embodiment of a transmission control device for a continuously variable transmission according to the present invention.
  • FIG. 2 is a diagram illustrating an example of a thrust ratio map.
  • FIG. 3 is a diagram illustrating a breakdown of the indicated thrust in a region where the thrust ratio is 1 or more.
  • FIG. 4 is a block diagram showing the control contents of the speed change controller.
  • FIG. 5 is a diagram illustrating an example of a gear ratio map.
  • FIG. 6 is a block diagram showing the control contents of the speed change controller.
  • FIG. 7 is a diagram illustrating an example of a gear ratio map.
  • FIG. 1 is a schematic configuration diagram showing a first embodiment of a transmission control device for a continuously variable transmission according to the present invention.
  • FIG. 2 is a diagram illustrating an example of a thrust ratio map.
  • FIG. 3 is a diagram illustrating a breakdown of the indicated thrust in a region where the thrust ratio is 1 or more.
  • FIG. 4 is
  • FIG. 8A is a diagram illustrating an example of an xz coordinate of a three-dimensional map for obtaining the chain elongation amount ⁇ L based on the primary pulley input torque Tp and the secondary pulley thrust Fs.
  • FIG. 8B is a diagram illustrating an example of yz coordinates of a three-dimensional map for obtaining the chain elongation amount ⁇ L based on the primary pulley input torque Tp and the secondary pulley thrust Fs.
  • FIG. 9 is a diagram showing an example of a map for obtaining the speed ratio upper limit and the speed ratio lower limit from the chain extension amount.
  • FIG. 10 is a time chart for explaining operational effects according to the present embodiment.
  • FIG. 10 is a time chart for explaining operational effects according to the present embodiment.
  • FIG. 11 is a diagram illustrating a case where the primary rotational speed Ns is different even when the primary input torque Tp is constant.
  • FIG. 12 is a block diagram showing the control contents of the speed change controller in the second embodiment.
  • FIG. 13A is a diagram illustrating an example of xz coordinates of a three-dimensional map for obtaining the chain elongation amount ⁇ L based on the primary pulley input torque Tp and the primary pulley rotation speed Ns.
  • FIG. 13B is a diagram illustrating an example of yz coordinates of a three-dimensional map for obtaining the chain elongation amount ⁇ L based on the primary pulley input torque Tp and the primary pulley rotation speed Ns.
  • FIG. 14 is a diagram for explaining the operational effects according to the second embodiment.
  • FIG. 1 is a schematic configuration diagram showing a first embodiment of a transmission control device for a continuously variable transmission according to the present invention.
  • the vehicle drive system includes an internal combustion engine 1 as a driving power source.
  • the output rotation of the internal combustion engine 1 is transmitted to the drive wheels 7 via the torque converter 2, the first gear train 3, the CVT 4, the second gear train 5, and the terminal reduction gear 6.
  • CVT4 is a chain type continuously variable transmission.
  • the CVT 4 includes a primary pulley 11, a secondary pulley 12, and a V chain 13.
  • the primary pulley 11 is provided on the input shaft.
  • the rotational torque of the internal combustion engine 1 is transmitted to the primary pulley 11 via the torque converter 2 and the first gear train 3.
  • Primary pulley 11 includes a fixed sheave and a movable sheave. In the movable sheave, the sheave surface faces the fixed sheave and the sheave surface. These sheave surfaces form V-grooves.
  • a hydraulic cylinder 15 is provided on the back surface of the movable sheave of the primary pulley 11. The hydraulic cylinder 15 displaces the movable sheave in the axial direction.
  • the basic structure of the secondary pulley 12 is the same as that of the primary pulley 11. That is, the secondary pulley 12 is provided on the output shaft. The rotational torque of the secondary pulley 12 is transmitted to the drive wheel 7 via the second gear train 5 and the terminal reduction device 6.
  • Secondary pulley 12 includes a fixed sheave and a movable sheave. In the movable sheave, the sheave surface faces the fixed sheave and the sheave surface. These sheave surfaces form V-grooves.
  • a hydraulic cylinder 16 is provided on the back surface of the movable sheave of the secondary pulley 12. The hydraulic cylinder 16 displaces the movable sheave in the axial direction.
  • the V chain 13 is an endless torque transmission member that is stretched between the primary pulley 11 and the secondary pulley 12.
  • the V chain 13 transmits the rotational torque of the primary pulley 11 to the secondary pulley 12.
  • the cross section of the V chain 13 has a V shape that gradually decreases in width toward the center of the V chain 13.
  • the V chain 13 has a large number of blocks connected in a ring via links and pins.
  • the V chain 13 is pulled by the primary pulley 11.
  • the secondary pulley is rotationally driven by this pulling force. Since the force acts in this way, the V chain 13 is elastically deformed and easily stretched.
  • the hydraulic cylinder 15 and the hydraulic cylinder 16 exert a thrust according to the supplied hydraulic pressure on the movable sheave.
  • the width of the V groove changes.
  • the winding radius of the V chain 13 with respect to the primary pulley 11 and the secondary pulley 12 changes.
  • the gear ratio of CVT 4 changes steplessly.
  • the “speed ratio” is a value obtained by dividing the rotational speed of the primary pulley 11 by the rotational speed of the secondary pulley 12.
  • the shift control of the CVT 4 is executed by the oil pump 10, the hydraulic control circuit 21, and the shift controller 22.
  • the oil pump 10 is driven by using a part of the power of the internal combustion engine 1.
  • the hydraulic control circuit 21 regulates the hydraulic pressure of the oil pump 10 and supplies it to the hydraulic cylinder 15 and the hydraulic cylinder 16.
  • the shift controller 22 controls the hydraulic control circuit 21.
  • the shift controller 22 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface).
  • the controller may be composed of a plurality of microcomputers.
  • the speed change controller 22 determines a target speed change ratio by a known method based on the load of the internal combustion engine 1 and the speed of the vehicle. Then, the transmission controller 22 performs feedback control so that the transmission ratio of the CVT 4 approaches the target transmission ratio.
  • the transmission controller 22 inputs detection data signals from an accelerator pedal operation amount sensor 41, a rotation speed sensor 42, a rotation speed sensor 43, and an inhibitor switch 45.
  • the accelerator pedal operation amount sensor 41 detects the accelerator pedal operation amount APO provided in the vehicle.
  • the rotation speed sensor 42 detects the rotation speed Np of the primary pulley 11.
  • the rotation speed sensor 43 detects the rotation speed Ns of the secondary pulley 12.
  • the rotational speed Ns of the secondary pulley 12 and the vehicle speed VSP are in a fixed proportional relationship. Therefore, the vehicle speed VSP is obtained from the rotational speed Ns detected by the rotational speed sensor 43.
  • the inhibitor switch 45 detects a select position of a selector lever provided in the vehicle.
  • the primary thrust is a thrust that the hydraulic cylinder 15 applies to the primary pulley 11.
  • the secondary thrust is a thrust that the hydraulic cylinder 16 applies to the secondary pulley 12.
  • Primary thrust and secondary thrust are set so that the target gear ratio is realized without sliding the endless torque transmission member. Therefore, the primary thrust and the secondary thrust are each set to be larger than the slip limit thrust and to be a balance thrust.
  • ⁇ Substantial slipping occurs when at least one of the primary thrust and the secondary thrust falls below a predetermined thrust (reference thrust). Then, wear may occur due to slipping, the surface state may deteriorate, and the durability of the endless torque transmitting member may be impaired. Therefore, it is necessary to prevent substantial slippage when transmitting torque between the endless torque transmitting member and the pulley.
  • a thrust that serves as a reference for preventing substantial slippage is a “slip limit thrust”. The reason that the substantial slip is described is that the V chain 13 causes a very small slip with respect to the primary pulley 11 and the secondary pulley 12 even in normal torque transmission. In the following description, substantial slip means slip of the V chain 13 that hinders torque transmission.
  • both the primary thrust and the secondary thrust must be set larger than the slip limit thrust. There is.
  • slip limit thrust (slip limit secondary thrust and slip limit primary thrust) is specifically calculated as follows. That is, the slip limit thrust (slip limit secondary thrust and slip limit primary thrust) is generally expressed by the following equation (1).
  • slip limit secondary thrust is expressed by the following equation (2).
  • winding radius Rp of the V chain 13 around the primary pulley 11 and the winding radius Rs of the V chain 13 around the secondary pulley 12 have the relationship of the following formula (4).
  • the expressions (1) and (2) are equivalent, that is, the secondary slip limit thrust Fs_min and the primary slip limit thrust Fp_min can be made the same.
  • the slip limit thrust is a value slightly larger than the value obtained by Equation (1).
  • “Balance thrust” is the thrust that satisfies the thrust ratio when the target gear ratio is achieved.
  • the thrust ratio is a ratio (Fp / Fs) between the primary thrust Fp and the secondary thrust Fs.
  • the gear ratio is 1 if the primary thrust and the secondary thrust are equal. If the primary thrust is smaller than the secondary thrust, the low gear ratio is obtained. If the primary thrust is larger than the secondary thrust, the high gear ratio is obtained.
  • the primary thrust and the secondary thrust need to be balanced thrusts that realize the thrust ratio determined by the target gear ratio and the load state applied to the endless torque transmission member, respectively.
  • the balance primary thrust Fp and the balance secondary thrust Fs are generally obtained from the thrust ratio map shown in FIG.
  • the horizontal axis represents an input torque ratio (Tp / Tin_max) which is a ratio of the input torque Tp to the primary pulley with respect to the transmission torque capacity (Tin_max) of the endless torque transmission member.
  • the vertical axis represents the ratio of the balance primary thrust to the balance secondary thrust for each target gear ratio, that is, the thrust ratio (Fp / Fs).
  • Transmission torque capacity refers to the maximum torque that can be transmitted from the primary pulley to the secondary pulley without slipping the endless torque transmission member.
  • the transmission torque capacity is the torque input to the primary pulley when the lower of the actual primary thrust and secondary thrust calculated backward from Equation (1) is the slip limit thrust. That is, the transmission torque capacity is the maximum input torque to the primary pulley that does not cause the endless torque transmission member to slip with respect to the actual primary thrust / secondary thrust.
  • the secondary thrust is set to at least the slip limit thrust, and the secondary thrust
  • the primary thrust may be set so that the balanced thrust becomes equal.
  • the primary thrust in a region where the thrust ratio is less than 1, the primary thrust may be set to at least the slip limit thrust and the secondary thrust may be set so as to be balanced with the primary thrust.
  • FIG. 3 is a diagram illustrating a breakdown of the indicated thrust in a region where the thrust ratio is 1 or more.
  • both the secondary thrust Fs and the primary thrust Fp are set larger than the slip limit thrust. Then, the shortage of the primary thrust is increased so that the ratio between the secondary thrust Fs and the primary thrust Fp satisfies the thrust ratio. As a result, the balance thrust is achieved without both the secondary thrust Fs and the primary thrust Fp falling below the slip limit thrust. In this way, the secondary thrust Fs and the primary thrust Fp are set.
  • FIG. 4 is a block diagram showing the control contents of the speed change controller.
  • blocks B1-B15 shown in FIG. 4 indicate the control function of the speed change controller 22 as a virtual unit, and do not mean physical existence.
  • the shift controller 22 calculates a primary input torque calculation unit B1, a slip limit thrust calculation unit B2, and a V chain transmission torque in order to calculate the slip limit thrust Fmin, the target speed ratio Dip, the secondary balance thrust Fs, and the primary balance thrust Fp.
  • a capacity calculator B3, a target primary rotational speed calculator B4, a target gear ratio setting unit B5, a thrust ratio calculator B6, a secondary balance thrust calculator B7, and a primary balance thrust calculator B8 are provided.
  • the primary input torque calculation unit B1 receives the engine torque Teng received from the engine control unit (ECU), the clutch engagement state, the torque converter lockup state (that is, the speed ratio and the fluid performance), the engine to the primary pulley. Based on the inertia torque in the portion, the primary input torque Tp is calculated.
  • the slip limit thrust calculation unit B2 calculates the slip limit thrust Fmin from the primary input torque Tp, the primary winding radius Rp, the V chain-pulley friction coefficient ⁇ , and the sheave angle ⁇ based on the formula (1). To do.
  • the primary winding radius Rp is calculated based on the normal gear ratio.
  • the slip limit thrust Fmin is calculated from the sheave angle ⁇ . In order to reliably prevent the V chain from slipping, a slightly larger value may be obtained by adding a margin to the calculation result obtained by Expression (1).
  • V chain transmission torque capacity calculation unit B3 calculates V chain transmission torque capacity Tin_mix (Tp in Expression (1)) from primary input torque Tp and slip limit thrust Fmin based on Expression (1).
  • the target primary rotation speed calculation unit B4 calculates the target primary rotation speed DNp from the accelerator pedal operation amount APO and the secondary rotation speed Ns based on the shift line (an example is shown in FIG. 5). An example of the shift line is shown in FIG. Specific calculation contents of the target primary rotation speed calculation unit B4 will be described later.
  • the target gear ratio setting unit B5 calculates the target gear ratio Dip from the target primary rotational speed DNp and the secondary rotational speed Ns.
  • the thrust ratio calculation unit B6 calculates the thrust ratio Fp / Fs from the target speed ratio Dip, the primary input torque Tp, and the input torque ratio Tp / Tin_max based on the V chain transmission torque capacity Tin_max.
  • the secondary balance thrust calculation unit B7 outputs Fmin as the secondary balance thrust Fs when the thrust ratio Fp / Fs is 1 or more, and Fmin / (Fp / Fs) when the thrust ratio Fp / Fs is less than 1. Output as secondary balance thrust Fs.
  • the primary balance thrust calculation unit B8 sets Fmin ⁇ Fp / Fs as the primary balance thrust Fp when the thrust ratio Fp / Fs is 1 or more, and sets Fmin as the primary balance thrust Fp when the thrust ratio Fp / Fs is less than 1.
  • the transmission controller 22 performs feedback control of the actual transmission ratio ip with respect to the target transmission ratio Dip, an actual transmission ratio calculation unit B9, a transmission ratio feedback secondary thrust calculation unit B10, a transmission ratio feedback primary thrust calculation unit B11, A transmission ratio feedback secondary thrust addition unit B12 and a transmission ratio feedback primary thrust addition unit B13 are provided.
  • the actual transmission ratio calculation unit B9 calculates the actual transmission ratio ip from the primary rotational speed Np and the secondary rotational speed Ns.
  • the transmission ratio feedback secondary thrust calculation unit B10 calculates the transmission ratio feedback secondary thrust Fs_fb based on the actual transmission ratio ip and the target transmission ratio Dip.
  • the transmission ratio feedback secondary thrust calculation unit B10 calculates the transmission ratio feedback secondary thrust Fs_fb within a range in which the instruction secondary thrust after addition of the transmission ratio feedback secondary thrust does not fall below the slip limit thrust.
  • the transmission ratio feedback primary thrust calculation unit B11 calculates a transmission ratio feedback primary thrust Fp_fb based on the actual transmission ratio ip and the target transmission ratio Dip.
  • the transmission ratio feedback primary thrust calculation unit B11 calculates the transmission ratio feedback primary thrust Fp_fb within a range in which the command primary thrust after addition of the transmission ratio feedback primary thrust does not fall below the slip limit thrust.
  • the gear ratio feedback secondary thrust adding unit B12 adds the gear ratio feedback secondary thrust Fs_fb to the secondary balance thrust Fs. As a result, gear ratio feedback is applied to the secondary thrust.
  • the transmission ratio feedback primary thrust adding unit B13 adds the transmission ratio feedback primary thrust Fp_fb to the primary balance thrust Fp. As a result, the gear ratio feedback is also applied to the primary thrust.
  • the transmission controller 22 includes a secondary hydraulic pressure conversion unit B14 and a primary hydraulic pressure conversion unit B15 in order to calculate the target secondary pressure Ps and the target primary pressure Pp.
  • the secondary hydraulic pressure conversion unit B14 calculates the target secondary pressure Ps by subtracting the centrifugal thrust and the spring thrust from the secondary thrust after the gear ratio feedback and dividing by the secondary pressure receiving area.
  • the centrifugal thrust is calculated from the rotational speed Ns of the secondary pulley 12 and a predetermined secondary pulley centrifugal thrust coefficient.
  • the spring thrust is calculated from the stroke distance of the hydraulic cylinder 16.
  • the primary hydraulic pressure conversion unit B15 calculates the target primary pressure Pp by subtracting the centrifugal thrust and the spring thrust from the primary thrust after the gear ratio feedback and dividing by the primary pressure receiving area.
  • the centrifugal thrust is calculated from the rotational speed Np of the primary pulley 11 and a predetermined secondary pulley centrifugal thrust coefficient.
  • the spring thrust is calculated from the stroke distance of the hydraulic cylinder 15.
  • the secondary pressure solenoid is adjusted based on the target secondary thrust. Further, the primary pressure solenoid is adjusted based on the target primary thrust. As a result, the V chain transmission torque capacity is secured in each of the secondary pulley and the primary pulley, and the target gear ratio is realized.
  • FIG. 5 is a diagram showing an example of the gear ratio map.
  • the target primary rotation speed calculation unit B4 calculates the target primary rotation speed DNp by applying the secondary rotation speed Ns (output rotation speed, ⁇ vehicle speed VSP) and the accelerator pedal operation amount APO to the gear ratio map.
  • FIG. 5 shows only one speed change line with a broken line in addition to the lowest speed ratio line and the highest speed ratio line in order to prevent the drawing from being complicated.
  • the target primary rotation speed is DNp0 from the shift line.
  • the target gear ratio is Dip from the secondary rotational speed Ns0 and the target primary rotational speed DNp.
  • the target gear ratio becomes the lowest gear ratio.
  • the secondary rotational speed is low (that is, when the vehicle speed is low)
  • the accelerator pedal operation amount is large
  • the target gear ratio becomes the lowest gear ratio.
  • the CVT 4 used in the present embodiment is a chain type continuously variable transmission that uses the V chain 13 as an endless torque transmission member. That is, the CVT 4 transmits the rotational torque of the primary pulley 11 to the secondary pulley 12 through the V chain 13.
  • the V chain 13 transmits the rotational driving force of the primary pulley 11 to the secondary pulley by a pulling force. For this reason, the V chain 13 is easily elastically deformed and stretched. If this elongation is not taken into account, the response of the shift control is delayed.
  • the target gear ratio is set to the minimum value, that is, when the vehicle travels in an overdrive state
  • the V chain endless torque transmission member
  • the secondary speed depends on the amount of extension. Pulley winding diameter increases.
  • the actual gear ratio changes to the low side from the target gear ratio.
  • the control unit executes feedback control so as to bring the actual gear ratio closer to the target gear ratio.
  • the V-chain endless torque transmission member
  • the actual gear ratio cannot be matched with the target gear ratio. Nevertheless, the control unit continues to perform feedback control. Then, the feedback value is accumulated on the upshift side.
  • the downshift operation of the continuously variable transmission is substantially stopped until the feedback value accumulated on the upshift side is eliminated. That is, the response of the shift control is delayed. When there is such a response delay, the driver feels uncomfortable.
  • the target gear ratio is limited to a realizable range in accordance with the input torque, thereby preventing the feedback value from being accumulated.
  • FIG. 6 is a block diagram showing the control contents of the speed change controller.
  • the speed change controller 22 includes the target primary rotation speed calculation unit B4 and the target speed ratio setting unit B5. The details will be described below.
  • the target primary rotation speed calculation unit B4 calculates the target primary rotation speed DNp based on the accelerator pedal operation amount APO and the rotation speed Ns of the secondary pulley 12. Although this description overlaps with the previous description, it will be described in order to understand the invention accurately. Specifically, the target primary pulley rotational speed DNp is obtained by applying the accelerator pedal operation amount APO and the rotational speed Ns of the secondary pulley 12 to the gear ratio map as shown in FIG. In FIG. 7, the secondary rotation speed is Ns1, and the accelerator pedal operation amount is APO1. In this case, the target primary rotational speed is DNp1 from the shift line.
  • the target gear ratio calculation unit B51 calculates the target gear ratio calculation value Dip1 by dividing the target primary rotation speed DNp by the rotation speed Ns of the secondary pulley 12.
  • the chain elongation calculating unit B52 obtains a chain elongation amount ⁇ L based on the primary input torque Tp and the secondary thrust Fs. Specifically, the chain extension amount ⁇ L is obtained by applying the primary input torque Tp and the secondary thrust Fs to the three-dimensional map whose xz coordinate is shown in FIG. 8A and whose yz coordinate is shown in FIG. 8B.
  • the elongation amount ⁇ L of the V chain 13 depends on the tension of the V chain 13. As can be seen from FIG.
  • the extension amount ⁇ L of the V chain 13 is as long as the transmission ratio of the primary pulley 11 and the secondary pulley 12, the movable sheave thrust Fs of the secondary pulley 12, and the rotation speed Np of the primary pulley 11 are constant. As the input torque Tp of the primary pulley 11 increases, it gradually increases. As can be seen from FIG. 8B, the extension amount ⁇ L of the V chain 13 is determined by the movement of the secondary pulley 12 if the input torque Tp and the rotational speed Np of the primary pulley 11 and the gear ratio of the primary pulley 11 and the secondary pulley 12 are constant. The larger the sheave thrust Fs, the larger.
  • the primary input torque Tp includes the engine torque Teng received from the engine control unit (ECU), the clutch engagement state, the torque converter lockup state (that is, the speed ratio and the fluid performance), the engine And the inertia torque in the portion from the primary pulley to the primary pulley.
  • the primary rotation speed Np is detected by the primary rotation speed sensor 42.
  • the secondary thrust Fs a value estimated from the input torque, a previously calculated value, or the like may be used.
  • the gear ratio upper limit calculation unit B53 calculates the gear ratio upper limit Dip_MAX based on the chain elongation amount ⁇ L. Specifically, the transmission gear ratio upper limit calculation unit B53 obtains the transmission gear ratio upper limit Dip_MAX by applying the chain extension amount ⁇ L to the transmission gear ratio map as shown in FIG. For example, the gear ratio upper limit Dip_MAX is the lowest gear ratio indicated by a broken line if the chain elongation amount ⁇ L is zero, and the lowest gear ratio indicated by a solid line if the chain elongation amount ⁇ L is the maximum value. During this time, the lowest gear ratio is set in proportion to the chain elongation. Similarly, the transmission gear ratio lower limit calculation unit B54 calculates the transmission gear ratio lower limit Dip_MIN based on the chain elongation amount ⁇ L.
  • the target gear ratio setting unit B55 sets the gear ratio upper limit Dip_MAX as the target gear ratio Dip when the target gear ratio calculated value Dip1 is larger than the gear ratio upper limit Dip_MAX.
  • the target speed ratio setting unit B55 sets the speed ratio lower limit Dip_MIN as the target speed ratio Dip when the target speed ratio calculated value Dip1 is smaller than the speed ratio lower limit Dip_MIN.
  • the target speed ratio setting unit B55 sets the target speed ratio calculated value Dip1 as the target speed ratio Dip if the target speed ratio calculated value Dip1 is equal to or lower than the speed ratio upper limit Dip_MAX and equal to or higher than the speed ratio lower limit Dip_MIN.
  • the speed ratio lower limit Dip_MIN is set as the target speed ratio Dip.
  • the gear ratio upper limit Dip_MAX and the gear ratio lower limit Dip_MIN are determined by specifications such as the chain length L and the position of the pulley stopper. Since the chain length L is determined by the tension acting on the chain, the chain length L is determined by the input torque Tp, the primary thrust Fp, the secondary thrust Fs, and the centrifugal term (which can be calculated based on the primary rotational speed Np and the secondary rotational speed Ns). I want.
  • the gear ratio upper limit Dip_MAX and the gear ratio lower limit Dip_MIN are determined by the chain length L and the position of the stopper.
  • the transmission ratio upper limit calculation unit B53 and the transmission ratio lower limit calculation unit B54 may set these calculation results in a map, and calculate the transmission ratio upper limit Dip_MAX and the transmission ratio lower limit Dip_MIN corresponding to each input. For example, when a stopper corresponding to the highest gear ratio is provided on the primary pulley side, the lowest gear ratio shifts low when the chain extends. When only the input torque Tp of each input is increased, the tension applied to the chain is increased and the chain is extended, so that the highest gear ratio is shifted low. When only the primary rotational speed Np and the secondary rotational speed Ns increase among the inputs, the tension applied to the chain is increased and the chain is extended, so that the highest gear ratio is shifted low. Furthermore, when only the secondary thrust Fs and the primary thrust Fp of each input are increased, the tension applied to the chain is increased and the chain is extended, so that the highest gear ratio is shifted Low.
  • FIG. 10 is a time chart for explaining operational effects according to the present embodiment.
  • the chain length L is calculated based on the torque Tp input to the primary pulley and the thrust Fs acting on the secondary pulley. At this time, the greater the thrust Fs acting on the secondary pulley, the longer the chain length L is calculated. Since the target speed ratio limit value is set accordingly, the target speed ratio limit value is changed at time t11 (FIG. 10E).
  • the target speed ratio limit value when the target speed ratio limit value is set based only on the torque Tp input to the primary pulley as in the comparative embodiment, the target speed ratio limit value also changes as the torque Tp increases. (FIG. 10 (E)). Therefore, in this way, the target gear ratio is unnecessarily limited, and the gear ratio width that can be actually used may be unduly narrowed.
  • the target speed ratio since the limit value of the target speed ratio is changed at time t11 (FIG. 10E), the target speed ratio is not limited unnecessarily and is actually used. The maximum speed ratio range is ensured within the possible range.
  • the gear ratio upper limit Dip_MAX is raised at the time of start where a high gear ratio is required by estimating the chain extension amount in accordance with the thrust increase correction at the time of start.
  • the target gear ratio is set to the minimum value, that is, when the vehicle travels in an overdrive state, if the input torque increases and the V chain (endless torque transmission member) extends, the secondary pulley will The winding diameter increases. Then, the actual gear ratio changes to the low side from the target gear ratio. As a result, the target speed ratio ascertained by the control unit is different from the actual speed ratio of the continuously variable transmission. Then, the control unit executes feedback control so as to bring the actual speed ratio closer to the target speed ratio. If this embodiment is not applied, when the V chain (endless torque transmission member) is extended, the actual gear ratio may not be matched with the target gear ratio. Nevertheless, the control unit continues to perform feedback control.
  • the feedback value is accumulated on the upshift side. If a downshift command is issued in a state where the feedback value is accumulated, the downshift operation of the continuously variable transmission is substantially stopped until the feedback value accumulated on the upshift side is eliminated. That is, the responsiveness of the shift control is lowered. When there is such a response delay, the driver feels uncomfortable.
  • the V chain endless torque transmission member
  • the control unit continues to perform feedback control. Then, the feedback value is accumulated on the downshift side.
  • the upshift operation of the continuously variable transmission is substantially stopped until the feedback value accumulated on the downshift side is eliminated. That is, the responsiveness of the shift control is lowered. When there is such a response delay, the driver feels uncomfortable.
  • the chain length L is calculated based on the torque Tp input to the primary pulley and the thrust Fs acting on the secondary pulley, and the limit value of the target gear ratio is set according to this.
  • the limit value of the target gear ratio is appropriately changed. Therefore, since a target speed ratio that cannot be realized is not set, a feedback value is not accumulated, a reduction in response of the speed change control can be prevented, and the driver does not feel uncomfortable.
  • the tension acting on the chain is also affected by the rotational speed of the pulley. That is, the greater the rotational speed of the pulley, the greater the centrifugal force acts and the greater the tension acting on the chain. Therefore, in this embodiment, the chain elongation amount ⁇ L is obtained based on the primary input torque Tp and the primary rotational speed Ns.
  • the engine torque Te has a predetermined value for each accelerator pedal operation amount (intake throttle opening) APO and engine rotational speed Ne, and is expressed as shown in FIG. Even when the engine torque is Te0 at a predetermined accelerator pedal operation amount APO, there are cases where the engine rotation speed is Ne2 and Ne3. If the accelerator pedal operation amount APO changes (becomes larger), the engine speed may be Ne1 even if the engine torque is Te0.
  • the primary rotational speed Ns may be different.
  • FIG. 12 is a block diagram showing the control contents of the speed change controller in the second embodiment.
  • the chain elongation calculation unit B521 calculates the chain elongation amount ⁇ L based on the primary input torque Tp and the primary rotational speed Ns. Specifically, the chain input amount ⁇ L is obtained by applying the primary input torque Tp and the primary rotational speed Ns to the three-dimensional map whose xz coordinate is shown in FIG. 13A and whose yz coordinate is shown in FIG. 13B.
  • FIG. 13A is similar to FIG. 8A. As can be seen from FIG.
  • the extension amount ⁇ L of the V chain 13 is determined by the input torque to the primary pulley 11, the movable sheave thrust of the secondary pulley 12, and the rotation speed Np of the primary pulley 11 if the primary pulley 11 is constant. Larger is bigger.
  • FIG. 14 is a time chart for explaining operational effects according to the second embodiment.
  • the chain elongation amount ⁇ L is calculated based on the torque Tp input to the primary pulley and the rotational speed Np of the primary pulley 11. At this time, the larger the rotation speed Np of the primary pulley 11, the longer the chain elongation amount ⁇ L is calculated. Since the target speed ratio limit value is set accordingly, the target speed ratio limit value is also changed after time t22 (FIG. 14E).
  • the target speed ratio limit value is set only based on the torque Tp input to the primary pulley as in the comparative embodiment, the target speed ratio limit value is not changed after time t22 (FIG. 14E )). Therefore, in this way, the target gear ratio is unnecessarily limited, and the gear ratio width that can be actually used may be unduly narrowed.
  • the target speed ratio limit value is changed after time t22, so that the target speed ratio is not unnecessarily limited, and the maximum speed change within the range that can be actually employed. A specific width is secured.
  • the gear ratio lower limit Dip_MIN is set on the premise that the maximum rotational speed at which the chain extends most is always input. Needed to be set.
  • the speed ratio lower limit Dip_MIN is changed according to the rotational speed, the target speed ratio is lowered in a region where the rotational speed is small. From the above, according to the present embodiment, a more appropriate speed ratio upper limit Dip_MAX is instructed, and the maximum speed ratio width is secured in a range that can be actually used.
  • the speed ratio lower limit Dip_MIN is lowered when traveling at the highest speed gear ratio at a low rotational speed.
  • the engine can run at a low rotational speed, and the effect of improving fuel efficiency can be obtained.
  • the chain elongation calculation unit may obtain the chain elongation amount ⁇ L based on the primary input torque Tp, the secondary thrust Fs, and the primary rotational speed Ns.
  • the chain elongation is obtained by applying the primary input torque Tp, the secondary thrust Fs, and the primary rotational speed Ns to the four-dimensional map having the chain elongation amount ⁇ L, the primary input torque Tp, the secondary thrust Fs, and the primary rotational speed Ns as axes.
  • the amount ⁇ L may be obtained.
  • the V chain is exemplified as the endless torque transmitting member, but the present invention is not limited to this.
  • rubber or other resin belts may be used.
  • the present invention can be applied to a structure in which elongation due to elastic deformation occurs when power is transmitted by acting on a secondary pulley.
  • the chain elongation amount is calculated based on the secondary thrust as the pulley thrust, but may be calculated based on the primary thrust.
  • the chain elongation amount is calculated based on the primary rotation speed as the pulley rotation speed, but may be calculated based on the secondary rotation speed.
  • the chain elongation amount ⁇ L is once calculated based on the primary input torque Tp and the secondary thrust Fs, or based on the primary input torque Tp and the primary rotational speed Ns, and the speed ratio upper limit Dip_MAX and the speed change
  • the lower limit Dip_MIN was determined.
  • the present invention is not limited to this, and a map or the like may be prepared in advance, and the gear ratio upper limit Dip_MAX and the gear ratio lower limit Dip_MIN may be directly obtained from the primary input torque Tp, the secondary thrust Fs, and the primary rotation speed Ns.

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Abstract

A transmission control device for a continuously variable transmission for shifting gears between a pair of pulleys via an endless torque transmission member wound around the pair of pulleys, the transmission control device being provided with: a target transmission gear ratio calculating unit for calculating the target transmission gear ratio for a transmission; a restriction value calculating unit for calculating the restriction value for the target transmission gear ratio on the basis of the torque inputted into the transmission, and the pulley thrust force and/or the pulley rotation speed; and a target transmission gear ratio setting unit for setting the restriction value as the target transmission gear ratio if the target transmission gear ratio calculated value calculated by means of the target transmission gear ratio calculating unit surpasses the restriction value and sets the target transmission gear ratio calculated value as the target transmission gear ratio if the target transmission gear ratio calculated value does not surpass the restriction value.

Description

無段変速機の変速制御装置Shift control device for continuously variable transmission
　この発明は、無段変速機の変速を制御する装置に関する。 This invention relates to a device for controlling the shift of a continuously variable transmission.
　入力軸に設けられるプライマリープーリーと、出力軸に設けられるセカンダリープーリーと、これらのプーリーに掛け渡される無端トルク伝達部材と、を備える無段変速機(Continuously Variable Transmission；以下適宜「ＣＶＴ」と称す)が公知である。このような無段変速機においては、プライマリープーリーは、固定シーブと可動シーブとを備える。またセカンダリープーリーも、固定シーブと可動シーブとを備える。 A continuously variable transmission (Continuously Variable Transmission; hereinafter referred to as "CVT" as appropriate) comprising a primary pulley provided on the input shaft, a secondary pulley provided on the output shaft, and an endless torque transmission member stretched around these pulleys Is known. In such a continuously variable transmission, the primary pulley includes a fixed sheave and a movable sheave. The secondary pulley also includes a fixed sheave and a movable sheave.
　変速比が制御されるときには、まず、アクセラレーターペダル操作量や車速が変速特性マップに適用されて、プライマリープーリーの目標回転速度が設定される。次いで、この目標回転速度を実現するための目標変速比が設定される。そして、この目標変速比が実現されるように、プライマリープーリーの可動シーブが軸方向に移動させられる。これに合わせて、セカンダリープーリーは、無端トルク伝達部材が滑らないように、所定の推力で無端トルク伝達部材を締め付ける。このようにすることで、無端トルク伝達部材の巻き付け径が変化し、変速比が無段階に制御される。 When the gear ratio is controlled, first, the accelerator pedal operation amount and the vehicle speed are applied to the shift characteristic map, and the target rotational speed of the primary pulley is set. Next, a target gear ratio for realizing this target rotation speed is set. Then, the movable sheave of the primary pulley is moved in the axial direction so that this target gear ratio is realized. In accordance with this, the secondary pulley tightens the endless torque transmission member with a predetermined thrust so that the endless torque transmission member does not slip. By doing in this way, the winding diameter of an endless torque transmission member changes and the gear ratio is controlled steplessly.
　無端トルク伝達部材には、スチールベルトやチェーンベルトがある。 There are steel belts and chain belts for endless torque transmission members.
　スチールベルトは、多数のエレメントがバンドによって環状に保持される。プライマリープーリーが、セカンダリープーリーにスチールベルトを押し付ける。この作用によって、動力が伝達される。 ス チ ー ル Many elements of a steel belt are held in an annular shape by a band. The primary pulley presses the steel belt against the secondary pulley. By this action, power is transmitted.
　一方、チェーンベルトは、多数のブロックがリンクやピンを介して環状に連結される。プライマリープーリーが、チェーンベルトを引っ張る。すると、セカンダリープーリーが回転駆動される。このとき、チェーンベルトは、引っ張り力によって弾性変形して伸びる可能性がある。この伸びが考慮されないと、変速制御の応答遅れが生じる。 On the other hand, the chain belt has a large number of blocks connected in a ring via links and pins. The primary pulley pulls the chain belt. Then, the secondary pulley is rotationally driven. At this time, the chain belt may be elastically deformed and stretched by a pulling force. If this elongation is not taken into account, a response delay of the shift control occurs.
　たとえば、目標変速比が最小値に設定される場合、すなわち車両がオーバードライブ状態で走行する場合を考える。このような場合に、入力トルクが増大してチェーンベルト(無端トルク伝達部材)が伸びると、伸び量に応じてセカンダリープーリーの巻き付け径が拡大する。すると、実際の変速比は目標変速比よりもロー側に変化する。この結果、制御ユニットが把握する目標変速比と無段変速機の実変速比とが相違する。すると、制御ユニットは、フィードバック制御によって、実変速比を目標変速比に近づけようとする。しかしながら、チェーンベルト(無端トルク伝達部材)が伸びているときには、実変速比を目標変速比に一致させることはできない。それでも、制御ユニットは、フィードバック制御を実行し続ける。すると、フィードバック値がアップシフト側に蓄積される。 For example, consider the case where the target gear ratio is set to the minimum value, that is, the vehicle travels in an overdrive state. In such a case, when the input torque increases and the chain belt (endless torque transmission member) extends, the winding diameter of the secondary pulley increases in accordance with the amount of extension. Then, the actual gear ratio changes to the low side from the target gear ratio. As a result, the target speed ratio ascertained by the control unit is different from the actual speed ratio of the continuously variable transmission. Then, the control unit tries to bring the actual speed ratio closer to the target speed ratio by feedback control. However, when the chain belt (endless torque transmission member) is extended, the actual gear ratio cannot be matched with the target gear ratio. Nevertheless, the control unit continues to perform feedback control. Then, the feedback value is accumulated on the upshift side.
　アップシフト側にフィードバック値が蓄積された状態で、ダウンシフト指令があると、そのフィードバック値が解消されるまで、無段変速機のダウンシフト操作が実質的に停止される。すなわち、変速制御の応答が遅れる。このような応答遅れがあると、運転者は違和感を感じる。 If a downshift command is issued while feedback values are accumulated on the upshift side, the downshift operation of the continuously variable transmission is substantially stopped until the feedback value is cleared. That is, the response of the shift control is delayed. When there is such a response delay, the driver feels uncomfortable.
　このように、チェーンベルト(無端トルク伝達部材)が伸びていなければ、実現できる目標変速比であっても、チェーンベルト(無端トルク伝達部材)が伸びているときには、実現できないことがある。 Thus, if the chain belt (endless torque transmission member) is not extended, even if the target gear ratio can be realized, it may not be realized when the chain belt (endless torque transmission member) is extended.
　そこで、ＪＰ－２００６－１８９０７９－Ａでは、フィードバック値の蓄積を防止するために、入力トルクに応じて目標変速比を実現可能な範囲に制限する。 Therefore, in JP-2006-189079-A, in order to prevent the accumulation of feedback values, the target gear ratio is limited to a realizable range according to the input torque.
　しかしながら、本件発明者らは、鋭意研究を重ねることで、ＪＰ－２００６－１８９０７９－Ａでは、車両の運転状態によっては、目標変速比が無用に制限されてしまい、実際に採用できる変速比幅が不当に狭められる可能性があることを見いだし、さらに精緻に無段変速機の変速を制御する手法を知見した。 However, the present inventors have conducted extensive research, and in JP-2006-189079-A, the target gear ratio is unnecessarily limited depending on the driving state of the vehicle. We found that there is a possibility of being narrowed unfairly, and found out a method for controlling the shift of the continuously variable transmission more precisely.
　本発明は、このような従来の問題点に着目してなされた。本発明の目的は、目標変速比が無用に制限されて、実際に採用できる変速比幅が不当に狭められることを防止できる無段変速機の変速制御装置を提供することである。 The present invention was made paying attention to such conventional problems. An object of the present invention is to provide a transmission control device for a continuously variable transmission that can prevent a target transmission gear ratio from being unnecessarily limited and an actual transmission gear ratio range from being unduly narrowed.
　本発明のある態様の無段変速機の変速制御装置は、一対のプーリーに掛け回された無端トルク伝達部材を介して前記一対のプーリー間で変速する。そして、変速機の目標変速比を算出する目標変速比算出部と、プーリー推力及びプーリー回転速度の少なくともいずれか一方と、変速機に入力されるトルクと、に基づいて目標変速比の制限値を算出する制限値算出部と、前記目標変速比算出部で算出された目標変速比算出値が前記制限値を越えれば、前記制限値を目標変速比として設定し、目標変速比算出値が前記制限値を越えなければ、目標変速比算出値を目標変速比として設定する目標変速比設定部と、を有する。 A shift control device for a continuously variable transmission according to an aspect of the present invention shifts between the pair of pulleys via an endless torque transmission member wound around the pair of pulleys. Then, a target speed ratio limit value is calculated based on a target speed ratio calculation unit that calculates the target speed ratio of the transmission, at least one of pulley thrust and pulley rotation speed, and torque input to the transmission. If the limit value calculation unit to calculate and the target gear ratio calculation value calculated by the target gear ratio calculation unit exceed the limit value, the limit value is set as the target gear ratio, and the target gear ratio calculation value is If it does not exceed the value, a target gear ratio setting unit that sets the target gear ratio calculated value as the target gear ratio is provided.
　本発明の実施形態、本発明の利点については、添付された図面とともに以下に詳細に説明される。 Embodiments of the present invention and advantages of the present invention will be described below in detail with reference to the accompanying drawings.
図１は、本発明による無段変速機の変速制御装置の第１実施形態を示す概略構成図である。FIG. 1 is a schematic configuration diagram showing a first embodiment of a transmission control device for a continuously variable transmission according to the present invention. 図２は、推力比マップの一例を示す図である。FIG. 2 is a diagram illustrating an example of a thrust ratio map. 図３は、推力比が１以上の領域での指示推力の内訳を例示する図である。FIG. 3 is a diagram illustrating a breakdown of the indicated thrust in a region where the thrust ratio is 1 or more. 図４は、変速コントローラーの制御内容を示すブロック図である。FIG. 4 is a block diagram showing the control contents of the speed change controller. 図５は、変速比マップの一例を示す図である。FIG. 5 is a diagram illustrating an example of a gear ratio map. 図６は、変速コントローラーの制御内容を示すブロック図である。FIG. 6 is a block diagram showing the control contents of the speed change controller. 図７は、変速比マップの一例を示す図である。FIG. 7 is a diagram illustrating an example of a gear ratio map. 図８Ａは、プライマリープーリー入力トルクＴｐ及びセカンダリープーリー推力Ｆｓに基づいてチェーン伸び量ΔＬを求めるための三次元マップのｘｚ座標の一例を示す図である。FIG. 8A is a diagram illustrating an example of an xz coordinate of a three-dimensional map for obtaining the chain elongation amount ΔL based on the primary pulley input torque Tp and the secondary pulley thrust Fs. 図８Ｂは、プライマリープーリー入力トルクＴｐ及びセカンダリープーリー推力Ｆｓに基づいてチェーン伸び量ΔＬを求めるための三次元マップのｙｚ座標の一例を示す図である。FIG. 8B is a diagram illustrating an example of yz coordinates of a three-dimensional map for obtaining the chain elongation amount ΔL based on the primary pulley input torque Tp and the secondary pulley thrust Fs. 図９は、チェーン伸び量から変速比上限及び変速比下限を求めるためのマップの一例を示す図である。FIG. 9 is a diagram showing an example of a map for obtaining the speed ratio upper limit and the speed ratio lower limit from the chain extension amount. 図１０は、本実施形態による作用効果を説明するタイムチャートである。FIG. 10 is a time chart for explaining operational effects according to the present embodiment. 図１１は、プライマリー入力トルクＴｐが一定であっても、プライマリー回転速度Ｎｓが異なる場合について説明する図である。FIG. 11 is a diagram illustrating a case where the primary rotational speed Ns is different even when the primary input torque Tp is constant. 図１２は、第２実施形態における変速コントローラーの制御内容を示すブロック図である。FIG. 12 is a block diagram showing the control contents of the speed change controller in the second embodiment. 図１３Ａは、プライマリープーリー入力トルクＴｐ及びプライマリープーリー回転速度Ｎｓに基づいてチェーン伸び量ΔＬを求めるための三次元マップのｘｚ座標の一例を示す図である。FIG. 13A is a diagram illustrating an example of xz coordinates of a three-dimensional map for obtaining the chain elongation amount ΔL based on the primary pulley input torque Tp and the primary pulley rotation speed Ns. 図１３Ｂは、プライマリープーリー入力トルクＴｐ及びプライマリープーリー回転速度Ｎｓに基づいてチェーン伸び量ΔＬを求めるための三次元マップのｙｚ座標の一例を示す図である。FIG. 13B is a diagram illustrating an example of yz coordinates of a three-dimensional map for obtaining the chain elongation amount ΔL based on the primary pulley input torque Tp and the primary pulley rotation speed Ns. 図１４は、第２実施形態による作用効果を説明する図である。FIG. 14 is a diagram for explaining the operational effects according to the second embodiment.
（第１実施形態）
　図１は、本発明による無段変速機の変速制御装置の第１実施形態を示す概略構成図である。 (First embodiment)
FIG. 1 is a schematic configuration diagram showing a first embodiment of a transmission control device for a continuously variable transmission according to the present invention.
　図１を参照すると、車両駆動システムは、走行用動力源として内燃エンジン１を備える。内燃エンジン１の出力回転は、トルクコンバーター２、第１ギヤ列３、ＣＶＴ４、第２ギヤ列５、及び終端減速装置６を介して、駆動輪７へ伝達される。 Referring to FIG. 1, the vehicle drive system includes an internal combustion engine 1 as a driving power source. The output rotation of the internal combustion engine 1 is transmitted to the drive wheels 7 via the torque converter 2, the first gear train 3, the CVT 4, the second gear train 5, and the terminal reduction gear 6.
　ＣＶＴ４は、チェーン式無段変速機である。ＣＶＴ４は、プライマリープーリー１１と、セカンダリープーリー１２と、Ｖチェーン１３と、を備える。 CVT4 is a chain type continuously variable transmission. The CVT 4 includes a primary pulley 11, a secondary pulley 12, and a V chain 13.
　プライマリープーリー１１は、入力軸に設けられる。内燃エンジン１の回転トルクは、トルクコンバーター２と第１ギヤ列３とを介して、プライマリープーリー１１に伝達される。プライマリープーリー１１は、固定シーブと、可動シーブと、を含む。可動シーブは、シーブ面が、固定シーブにシーブ面に対向する。これらのシーブ面によって、Ｖ溝が形成される。プライマリープーリー１１の可動シーブの背面には、油圧シリンダー１５が設けられる。油圧シリンダー１５は、可動シーブを軸方向に変位させる。 The primary pulley 11 is provided on the input shaft. The rotational torque of the internal combustion engine 1 is transmitted to the primary pulley 11 via the torque converter 2 and the first gear train 3. Primary pulley 11 includes a fixed sheave and a movable sheave. In the movable sheave, the sheave surface faces the fixed sheave and the sheave surface. These sheave surfaces form V-grooves. A hydraulic cylinder 15 is provided on the back surface of the movable sheave of the primary pulley 11. The hydraulic cylinder 15 displaces the movable sheave in the axial direction.
　セカンダリープーリー１２の基本構造はプライマリープーリー１１と同様である。すなわちセカンダリープーリー１２は、出力軸に設けられる。セカンダリープーリー１２の回転トルクは、第２ギヤ列５と終端減速装置６とを介して駆動輪７に伝達される。セカンダリープーリー１２は、固定シーブと、可動シーブと、を含む。可動シーブは、シーブ面が、固定シーブにシーブ面に対向する。これらのシーブ面によって、Ｖ溝が形成される。セカンダリープーリー１２の可動シーブの背面には、油圧シリンダー１６が設けられる。油圧シリンダー１６は、可動シーブを軸方向に変位させる。 The basic structure of the secondary pulley 12 is the same as that of the primary pulley 11. That is, the secondary pulley 12 is provided on the output shaft. The rotational torque of the secondary pulley 12 is transmitted to the drive wheel 7 via the second gear train 5 and the terminal reduction device 6. Secondary pulley 12 includes a fixed sheave and a movable sheave. In the movable sheave, the sheave surface faces the fixed sheave and the sheave surface. These sheave surfaces form V-grooves. A hydraulic cylinder 16 is provided on the back surface of the movable sheave of the secondary pulley 12. The hydraulic cylinder 16 displaces the movable sheave in the axial direction.
　Ｖチェーン１３は、プライマリープーリー１１とセカンダリープーリー１２とに掛け渡される無端トルク伝達部材である。Ｖチェーン１３は、プライマリープーリー１１の回転トルクをセカンダリープーリー１２に伝達する。Ｖチェーン１３の断面は、Ｖチェーン１３の中心方向に向かって幅を漸減するＶ字形である。Ｖチェーン１３は、多数のブロックがリンクやピンを介して環状に連結されている。Ｖチェーン１３は、プライマリープーリー１１によって引っ張られる。この引っ張り力によって、セカンダリープーリーが回転駆動される。このように力が作用するので、Ｖチェーン１３は、弾性変形して伸びやすい。 The V chain 13 is an endless torque transmission member that is stretched between the primary pulley 11 and the secondary pulley 12. The V chain 13 transmits the rotational torque of the primary pulley 11 to the secondary pulley 12. The cross section of the V chain 13 has a V shape that gradually decreases in width toward the center of the V chain 13. The V chain 13 has a large number of blocks connected in a ring via links and pins. The V chain 13 is pulled by the primary pulley 11. The secondary pulley is rotationally driven by this pulling force. Since the force acts in this way, the V chain 13 is elastically deformed and easily stretched.
　油圧シリンダー１５及び油圧シリンダー１６は、供給される油圧に応じた推力を可動シーブに及ぼす。この結果、Ｖ溝の幅が変化する。すると、プライマリープーリー１１及びセカンダリープーリー１２に対するＶチェーン１３の巻き付き半径が変化する。この結果、ＣＶＴ４は変速比は、無段階に変化する。なお、「変速比」は、プライマリープーリー１１の回転速度をセカンダリープーリー１２の回転速度で割って得られる値である。 The hydraulic cylinder 15 and the hydraulic cylinder 16 exert a thrust according to the supplied hydraulic pressure on the movable sheave. As a result, the width of the V groove changes. Then, the winding radius of the V chain 13 with respect to the primary pulley 11 and the secondary pulley 12 changes. As a result, the gear ratio of CVT 4 changes steplessly. The “speed ratio” is a value obtained by dividing the rotational speed of the primary pulley 11 by the rotational speed of the secondary pulley 12.
　ＣＶＴ４の変速制御は、オイルポンプ１０と、油圧制御回路２１と、変速コントローラー２２と、によって実行される。オイルポンプ１０は、内燃エンジン１の動力の一部が利用されて駆動される。油圧制御回路２１は、オイルポンプ１０の油圧を調圧して、油圧シリンダー１５及び油圧シリンダー１６に供給する。変速コントローラー２２は、油圧制御回路２１を制御する。 The shift control of the CVT 4 is executed by the oil pump 10, the hydraulic control circuit 21, and the shift controller 22. The oil pump 10 is driven by using a part of the power of the internal combustion engine 1. The hydraulic control circuit 21 regulates the hydraulic pressure of the oil pump 10 and supplies it to the hydraulic cylinder 15 and the hydraulic cylinder 16. The shift controller 22 controls the hydraulic control circuit 21.
　変速コントローラー２２は、中央演算装置(ＣＰＵ)、読み出し専用メモリー(ＲＯＭ)、ランダムアクセスメモリー(ＲＡＭ)及び入出力インターフェース(Ｉ／Ｏインターフェース)を備えたマイクロコンピューターで構成される。コントローラーは、複数のマイクロコンピューターで構成されてもよい。 The shift controller 22 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller may be composed of a plurality of microcomputers.
　変速コントローラー２２は、内燃エンジン１の負荷と車両の速度に基づき公知の方法で目標変速比を決定する。そして、変速コントローラー２２は、ＣＶＴ４の変速比が目標変速比に近づくように、フィードバック制御する。 The speed change controller 22 determines a target speed change ratio by a known method based on the load of the internal combustion engine 1 and the speed of the vehicle. Then, the transmission controller 22 performs feedback control so that the transmission ratio of the CVT 4 approaches the target transmission ratio.
　変速コントローラー２２は、アクセラレーターペダル操作量センサー４１と、回転速度センサー４２と、回転速度センサー４３と、インヒビタースイッチ４５と、から、それぞれの検出データの信号を入力する。なお、アクセラレーターペダル操作量センサー４１は、車両に備えられたアクセラレーターペダルの操作量ＡＰＯを検出する。回転速度センサー４２は、プライマリープーリー１１の回転速度Ｎｐを検出する。回転速度センサー４３は、セカンダリープーリー１２の回転速度Ｎｓを検出する。セカンダリープーリー１２の回転速度Ｎｓと車速ＶＳＰとは、一定の比例関係にある。そこで、車速ＶＳＰは、回転速度センサー４３が検出する回転速度Ｎｓから求められる。インヒビタースイッチ４５は、車両に備えられたセレクターレバーのセレクト位置を検出する。 The transmission controller 22 inputs detection data signals from an accelerator pedal operation amount sensor 41, a rotation speed sensor 42, a rotation speed sensor 43, and an inhibitor switch 45. The accelerator pedal operation amount sensor 41 detects the accelerator pedal operation amount APO provided in the vehicle. The rotation speed sensor 42 detects the rotation speed Np of the primary pulley 11. The rotation speed sensor 43 detects the rotation speed Ns of the secondary pulley 12. The rotational speed Ns of the secondary pulley 12 and the vehicle speed VSP are in a fixed proportional relationship. Therefore, the vehicle speed VSP is obtained from the rotational speed Ns detected by the rotational speed sensor 43. The inhibitor switch 45 detects a select position of a selector lever provided in the vehicle.
　続いて、ＣＶＴ４のプライマリー推力及びセカンダリー推力の設定方法が説明される。なお、プライマリー推力は、油圧シリンダー１５がプライマリープーリー１１に加える推力である。セカンダリー推力は、油圧シリンダー１６がセカンダリープーリー１２に加える推力である。 Subsequently, a method for setting the primary thrust and the secondary thrust of the CVT 4 will be described. The primary thrust is a thrust that the hydraulic cylinder 15 applies to the primary pulley 11. The secondary thrust is a thrust that the hydraulic cylinder 16 applies to the secondary pulley 12.
　プライマリー推力及びセカンダリー推力は、無端トルク伝達部材を滑らせることなく、かつ目標変速比が実現されるように設定される。そのため、プライマリー推力及びセカンダリー推力は、それぞれが滑り限界推力よりも大きく、かつバランス推力となるように設定される。 Primary thrust and secondary thrust are set so that the target gear ratio is realized without sliding the endless torque transmission member. Therefore, the primary thrust and the secondary thrust are each set to be larger than the slip limit thrust and to be a balance thrust.
　ここで「滑り限界推力」が説明される。 ”Slip limit thrust” is explained here.
　プライマリー推力及びセカンダリー推力の少なくとも一方が、所定推力(基準推力)を下回ると、実質的な滑りが発生する。すると、滑りによって損耗が生じ、表面状態が悪化して、無端トルク伝達部材の耐久性が損なわれるおそれがある。したがって、無端トルク伝達部材とプーリーとの間でトルクを伝達するときに、実質的な滑りが発生しないようにする必要がある。実質的な滑りを発生させないための基準となる推力が、「滑り限界推力」である。なお、実質的な滑りと記載したのは、Ｖチェーン１３は、正常なトルク伝達においてもプライマリープーリー１１及びセカンダリープーリー１２に対してそれぞれ極微小な滑りを生じるからである。以下の説明において、実質的な滑りは、トルク伝達に支障を来すようなＶチェーン１３の滑りを意味する。 ¡Substantial slipping occurs when at least one of the primary thrust and the secondary thrust falls below a predetermined thrust (reference thrust). Then, wear may occur due to slipping, the surface state may deteriorate, and the durability of the endless torque transmitting member may be impaired. Therefore, it is necessary to prevent substantial slippage when transmitting torque between the endless torque transmitting member and the pulley. A thrust that serves as a reference for preventing substantial slippage is a “slip limit thrust”. The reason that the substantial slip is described is that the V chain 13 causes a very small slip with respect to the primary pulley 11 and the secondary pulley 12 even in normal torque transmission. In the following description, substantial slip means slip of the V chain 13 that hinders torque transmission.
　プライマリープーリーと無端トルク伝達部材との間、及びセカンダリープーリーと無端トルク伝達部材との間の双方で滑りを発生させないためには、プライマリー推力及びセカンダリー推力がともに滑り限界推力よりも大きく設定される必要がある。 In order to prevent slippage between the primary pulley and the endless torque transmission member and between the secondary pulley and the endless torque transmission member, both the primary thrust and the secondary thrust must be set larger than the slip limit thrust. There is.
　滑り限界推力(滑り限界セカンダリー推力及び滑り限界プライマリー推力)は、具体的には以下のように求められる。すなわち、滑り限界推力(滑り限界セカンダリー推力及び滑り限界プライマリー推力)は、一般的に次式(１)で表される。 The slip limit thrust (slip limit secondary thrust and slip limit primary thrust) is specifically calculated as follows. That is, the slip limit thrust (slip limit secondary thrust and slip limit primary thrust) is generally expressed by the following equation (1).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　また滑り限界セカンダリー推力は、次式(２)でも表される。 Also, the slip limit secondary thrust is expressed by the following equation (2).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　通常、変速比をｉｐとすると、プライマリープーリー入力トルクＴｐとセカンダリープーリー入力トルクＴｓとは、次式(３)の関係にある。 Usually, assuming that the gear ratio is ip, the primary pulley input torque Tp and the secondary pulley input torque Ts are in the relationship of the following equation (3).
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　またプライマリープーリー１１へのＶチェーン１３の巻き付き半径Ｒｐとセカンダリープーリー１２へのＶチェーン１３の巻き付き半径Ｒｓとは、次式(４)の関係にある。 Further, the winding radius Rp of the V chain 13 around the primary pulley 11 and the winding radius Rs of the V chain 13 around the secondary pulley 12 have the relationship of the following formula (4).
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　以上の関係から、式(１)と式(２)とは同等であり、すなわちセカンダリー滑り限界推力Ｆｓ＿ｍｉｎとプライマリー滑り限界推力Ｆｐ＿ｍｉｎとは、同じとすることができる。部品の製造誤差などがあっても確実にベルト滑りを回避するには、滑り限界推力が式(１)で得られる値よりも少し大きな値とされることが望ましい。 From the above relationship, the expressions (1) and (2) are equivalent, that is, the secondary slip limit thrust Fs_min and the primary slip limit thrust Fp_min can be made the same. In order to reliably avoid the belt slip even if there is a manufacturing error of parts, it is desirable that the slip limit thrust is a value slightly larger than the value obtained by Equation (1).
　次に「バランス推力」が説明される。 Next, “balance thrust” will be explained.
　「バランス推力」とは、目標変速比を実現するときの推力比を満たす推力である。なお推力比とは、プライマリー推力Ｆｐとセカンダリー推力Ｆｓとの比(Ｆｐ／Ｆｓ)である。 “Balance thrust” is the thrust that satisfies the thrust ratio when the target gear ratio is achieved. The thrust ratio is a ratio (Fp / Fs) between the primary thrust Fp and the secondary thrust Fs.
　プライマリープーリーに作用する入力トルクがゼロ、すなわち無負荷状態では、プライマリー推力とセカンダリー推力とが同等であれば、変速比１となる。プライマリー推力がセカンダリー推力よりも小さければ、ロー側の変速比になる。プライマリー推力がセカンダリー推力よりも大きければ、ハイ側の変速比になる。 When the input torque acting on the primary pulley is zero, that is, when there is no load, the gear ratio is 1 if the primary thrust and the secondary thrust are equal. If the primary thrust is smaller than the secondary thrust, the low gear ratio is obtained. If the primary thrust is larger than the secondary thrust, the high gear ratio is obtained.
　プライマリープーリーに作用する入力トルクが正、すなわちベルトに負荷がかかる状態では、プライマリープーリー側のベルト入口の張力が、出口の張力よりも大きい。この結果、プライマリー巻き付き半径が小さくなろうとする。そのため無負荷状態のときよりも、より大きなプライマリー推力が必要である。したがって、目標変速比を実現するために、プライマリー推力及びセカンダリー推力は、それぞれ目標変速比や無端トルク伝達部材にかかる負荷の状態により定まる推力比を実現するようなバランス推力とする必要がある。 ¡When the input torque acting on the primary pulley is positive, that is, when the belt is loaded, the tension at the belt inlet on the primary pulley side is greater than the tension at the outlet. As a result, the primary winding radius tends to be reduced. Therefore, a larger primary thrust is required than in the no-load state. Therefore, in order to realize the target gear ratio, the primary thrust and the secondary thrust need to be balanced thrusts that realize the thrust ratio determined by the target gear ratio and the load state applied to the endless torque transmission member, respectively.
　バランスプライマリー推力Ｆｐ及びバランスセカンダリー推力Ｆｓは、一般的に図２に示した推力比マップから求められる。図２において横軸は、無端トルク伝達部材の伝達トルク容量(Ｔｉｎ＿ｍａｘ)に対するプライマリープーリーへの入力トルクＴｐの割合である入力トルク比(Ｔｐ／Ｔｉｎ＿ｍａｘ)である。図２において縦軸は、各目標変速比ごとのバランスセカンダリー推力に対するバランスプライマリー推力の割合、すなわち推力比(Ｆｐ／Ｆｓ)である。 The balance primary thrust Fp and the balance secondary thrust Fs are generally obtained from the thrust ratio map shown in FIG. In FIG. 2, the horizontal axis represents an input torque ratio (Tp / Tin_max) which is a ratio of the input torque Tp to the primary pulley with respect to the transmission torque capacity (Tin_max) of the endless torque transmission member. In FIG. 2, the vertical axis represents the ratio of the balance primary thrust to the balance secondary thrust for each target gear ratio, that is, the thrust ratio (Fp / Fs).
　なお「伝達トルク容量」とは、無端トルク伝達部材が滑ることなくプライマリープーリーからセカンダリープーリーに伝達可能な最大トルクのことを言う。換言すれば、伝達トルク容量は、式(１)から逆算される実際のプライマリー推力及びセカンダリー推力のうち低いほうを滑り限界推力としたときに、プライマリープーリーへ入力されるトルクである。つまり、伝達トルク容量は、実際のプライマリー推力・セカンダリー推力に対して無端トルク伝達部材の滑りを起こさない最大のプライマリープーリーへの入力トルクである。 "Transmission torque capacity" refers to the maximum torque that can be transmitted from the primary pulley to the secondary pulley without slipping the endless torque transmission member. In other words, the transmission torque capacity is the torque input to the primary pulley when the lower of the actual primary thrust and secondary thrust calculated backward from Equation (1) is the slip limit thrust. That is, the transmission torque capacity is the maximum input torque to the primary pulley that does not cause the endless torque transmission member to slip with respect to the actual primary thrust / secondary thrust.
　以上から、無端トルク伝達部材を滑らせることなく、かつ目標変速比が実現されるには、推力比が１以上の領域では、セカンダリー推力が少なくとも滑り限界推力に設定されるとともに、このセカンダリー推力とのバランス推力になるようにプライマリー推力が設定されればよい。一方、推力比が１未満の領域では、プライマリー推力が少なくとも滑り限界推力に設定されるとともに、このプライマリー推力とのバランス推力になるようにセカンダリー推力が設定されればよい。 From the above, in order to achieve the target gear ratio without sliding the endless torque transmission member, in the region where the thrust ratio is 1 or more, the secondary thrust is set to at least the slip limit thrust, and the secondary thrust The primary thrust may be set so that the balanced thrust becomes equal. On the other hand, in a region where the thrust ratio is less than 1, the primary thrust may be set to at least the slip limit thrust and the secondary thrust may be set so as to be balanced with the primary thrust.
　図３は、推力比が１以上の領域での指示推力の内訳を例示する図である。 FIG. 3 is a diagram illustrating a breakdown of the indicated thrust in a region where the thrust ratio is 1 or more.
　まずセカンダリー推力Ｆｓとプライマリー推力Ｆｐとの両方が滑り限界推力よりも大きく設定される。そして、セカンダリー推力Ｆｓとプライマリー推力Ｆｐとの比が、推力比を満たすように、プライマリー推力の不足分が増大される。この結果、セカンダリー推力Ｆｓ及びプライマリー推力Ｆｐの両方が滑り限界推力を下回ることなく、バランス推力が達成される。このようにして、セカンダリー推力Ｆｓ及びプライマリー推力Ｆｐが設定される。 First, both the secondary thrust Fs and the primary thrust Fp are set larger than the slip limit thrust. Then, the shortage of the primary thrust is increased so that the ratio between the secondary thrust Fs and the primary thrust Fp satisfies the thrust ratio. As a result, the balance thrust is achieved without both the secondary thrust Fs and the primary thrust Fp falling below the slip limit thrust. In this way, the secondary thrust Fs and the primary thrust Fp are set.
　図４は、変速コントローラーの制御内容を示すブロック図である。 FIG. 4 is a block diagram showing the control contents of the speed change controller.
　なお図４に示すブロックＢ１－Ｂ１５は、変速コントローラー２２の制御機能を仮想的なユニットとして示すものであり、物理的な存在を意味しない。 Note that the blocks B1-B15 shown in FIG. 4 indicate the control function of the speed change controller 22 as a virtual unit, and do not mean physical existence.
　変速コントローラー２２は、滑り限界推力Ｆｍｉｎ、目標変速比Ｄｉｐ、セカンダリーバランス推力Ｆｓ、プライマリーバランス推力Ｆｐを算出するために、プライマリー入力トルク算出部Ｂ１と、滑り限界推力算出部Ｂ２と、Ｖチェーン伝達トルク容量算出部Ｂ３と、目標プライマリー回転速度算出部Ｂ４と、目標変速比設定部Ｂ５と、推力比算出部Ｂ６と、セカンダリーバランス推力算出部Ｂ７と、プライマリーバランス推力算出部Ｂ８と、を備える。 The shift controller 22 calculates a primary input torque calculation unit B1, a slip limit thrust calculation unit B2, and a V chain transmission torque in order to calculate the slip limit thrust Fmin, the target speed ratio Dip, the secondary balance thrust Fs, and the primary balance thrust Fp. A capacity calculator B3, a target primary rotational speed calculator B4, a target gear ratio setting unit B5, a thrust ratio calculator B6, a secondary balance thrust calculator B7, and a primary balance thrust calculator B8 are provided.
　プライマリー入力トルク算出部Ｂ１は、エンジン制御ユニット(ＥＣＵ)から受信するエンジントルクＴｅｎｇと、クラッチの締結状態と、トルクコンバーターのロックアップ状態(すなわち速度比及び流体性能)と、エンジンからプライマリープーリーまでの部分におけるイナーシャトルクと、に基づいて、プライマリー入力トルクＴｐを算出する。 The primary input torque calculation unit B1 receives the engine torque Teng received from the engine control unit (ECU), the clutch engagement state, the torque converter lockup state (that is, the speed ratio and the fluid performance), the engine to the primary pulley. Based on the inertia torque in the portion, the primary input torque Tp is calculated.
　滑り限界推力算出部Ｂ２は、式(１)に基づいて、プライマリー入力トルクＴｐと、プライマリー巻き付き半径Ｒｐと、Ｖチェーン－プーリー間摩擦係数μと、シーブ角αから滑り限界推力Ｆｍｉｎと、を算出する。なおプライマリー巻き付き半径Ｒｐは、通常変速比に基づいて算出される。滑り限界推力Ｆｍｉｎは、シーブ角αから算出される。またＶチェーンの滑りを確実に防止するために、式(１)による算出結果にマージンを加えて少し大きな値としてもよい。 The slip limit thrust calculation unit B2 calculates the slip limit thrust Fmin from the primary input torque Tp, the primary winding radius Rp, the V chain-pulley friction coefficient μ, and the sheave angle α based on the formula (1). To do. The primary winding radius Rp is calculated based on the normal gear ratio. The slip limit thrust Fmin is calculated from the sheave angle α. In order to reliably prevent the V chain from slipping, a slightly larger value may be obtained by adding a margin to the calculation result obtained by Expression (1).
　Ｖチェーン伝達トルク容量算出部Ｂ３は、式(１)に基づいて、プライマリー入力トルクＴｐと滑り限界推力ＦｍｉｎとからＶチェーン伝達トルク容量Ｔｉｎ＿ｍｉｘ(式(１)のＴｐ)を算出する。 V chain transmission torque capacity calculation unit B3 calculates V chain transmission torque capacity Tin_mix (Tp in Expression (1)) from primary input torque Tp and slip limit thrust Fmin based on Expression (1).
　目標プライマリー回転速度算出部Ｂ４は、変速線(一例を図５に示す)に基づいてアクセラレーターペダル操作量ＡＰＯとセカンダリー回転速度Ｎｓとから目標プライマリー回転速度ＤＮｐを算出する。なお変速線の一例が図５に示される。目標プライマリー回転速度算出部Ｂ４の具体的な算出内容は、後述される。 The target primary rotation speed calculation unit B4 calculates the target primary rotation speed DNp from the accelerator pedal operation amount APO and the secondary rotation speed Ns based on the shift line (an example is shown in FIG. 5). An example of the shift line is shown in FIG. Specific calculation contents of the target primary rotation speed calculation unit B4 will be described later.
　目標変速比設定部Ｂ５は、目標プライマリー回転速度ＤＮｐとセカンダリー回転速度Ｎｓとから目標変速比Ｄｉｐを算出する。 The target gear ratio setting unit B5 calculates the target gear ratio Dip from the target primary rotational speed DNp and the secondary rotational speed Ns.
　推力比算出部Ｂ６は、目標変速比Ｄｉｐと、プライマリー入力トルクＴｐと、Ｖチェーン伝達トルク容量Ｔｉｎ＿ｍａｘを基とする入力トルク比Ｔｐ／Ｔｉｎ＿ｍａｘとから推力比Ｆｐ／Ｆｓを算出する。 The thrust ratio calculation unit B6 calculates the thrust ratio Fp / Fs from the target speed ratio Dip, the primary input torque Tp, and the input torque ratio Tp / Tin_max based on the V chain transmission torque capacity Tin_max.
　セカンダリーバランス推力算出部Ｂ７は、推力比Ｆｐ／Ｆｓが１以上の場合にはＦｍｉｎをセカンダリーバランス推力Ｆｓとして出力し、推力比Ｆｐ／Ｆｓが１未満の場合にはＦｍｉｎ／（Ｆｐ／Ｆｓ）をセカンダリーバランス推力Ｆｓとして出力する。 The secondary balance thrust calculation unit B7 outputs Fmin as the secondary balance thrust Fs when the thrust ratio Fp / Fs is 1 or more, and Fmin / (Fp / Fs) when the thrust ratio Fp / Fs is less than 1. Output as secondary balance thrust Fs.
　プライマリーバランス推力算出部Ｂ８は、推力比Ｆｐ／Ｆｓが１以上の場合にはＦｍｉｎ×Ｆｐ／Ｆｓをプライマリーバランス推力Ｆｐとし、推力比Ｆｐ／Ｆｓが１未満の場合にはＦｍｉｎをプライマリーバランス推力Ｆｐとする。 The primary balance thrust calculation unit B8 sets Fmin × Fp / Fs as the primary balance thrust Fp when the thrust ratio Fp / Fs is 1 or more, and sets Fmin as the primary balance thrust Fp when the thrust ratio Fp / Fs is less than 1. And
　また変速コントローラー２２は、目標変速比Ｄｉｐに対する実変速比ｉｐをフィードバック制御するために、実変速比算出部Ｂ９と、変速比フィードバックセカンダリー推力算出部Ｂ１０と、変速比フィードバックプライマリー推力算出部Ｂ１１と、変速比フィードバックセカンダリー推力加算部Ｂ１２と、変速比フィードバックプライマリー推力加算部Ｂ１３と、を備える。 Further, the transmission controller 22 performs feedback control of the actual transmission ratio ip with respect to the target transmission ratio Dip, an actual transmission ratio calculation unit B9, a transmission ratio feedback secondary thrust calculation unit B10, a transmission ratio feedback primary thrust calculation unit B11, A transmission ratio feedback secondary thrust addition unit B12 and a transmission ratio feedback primary thrust addition unit B13 are provided.
　実変速比算出部Ｂ９は、プライマリー回転速度Ｎｐとセカンダリー回転速度Ｎｓとから実変速比ｉｐを算出する。 The actual transmission ratio calculation unit B9 calculates the actual transmission ratio ip from the primary rotational speed Np and the secondary rotational speed Ns.
　変速比フィードバックセカンダリー推力算出部Ｂ１０は、実変速比ｉｐと目標変速比Ｄｉｐとに基づいて変速比フィードバックセカンダリー推力Ｆｓ＿ｆｂを算出する。なお、変速比フィードバックセカンダリー推力算出部Ｂ１０は、変速比フィードバックセカンダリー推力加算後の指示セカンダリー推力が滑り限界推力を下回らない範囲で、変速比フィードバックセカンダリー推力Ｆｓ＿ｆｂを算出する。 The transmission ratio feedback secondary thrust calculation unit B10 calculates the transmission ratio feedback secondary thrust Fs_fb based on the actual transmission ratio ip and the target transmission ratio Dip. The transmission ratio feedback secondary thrust calculation unit B10 calculates the transmission ratio feedback secondary thrust Fs_fb within a range in which the instruction secondary thrust after addition of the transmission ratio feedback secondary thrust does not fall below the slip limit thrust.
　変速比フィードバックプライマリー推力算出部Ｂ１１は、実変速比ｉｐと目標変速比Ｄｉｐに基づいて変速比フィードバックプライマリー推力Ｆｐ＿ｆｂを算出する。なお、変速比フィードバックプライマリー推力算出部Ｂ１１は、変速比フィードバックプライマリー推力加算後の指示プライマリー推力が滑り限界推力を下回らない範囲で、変速比フィードバックプライマリー推力Ｆｐ＿ｆｂを算出する。 The transmission ratio feedback primary thrust calculation unit B11 calculates a transmission ratio feedback primary thrust Fp_fb based on the actual transmission ratio ip and the target transmission ratio Dip. The transmission ratio feedback primary thrust calculation unit B11 calculates the transmission ratio feedback primary thrust Fp_fb within a range in which the command primary thrust after addition of the transmission ratio feedback primary thrust does not fall below the slip limit thrust.
　変速比フィードバックセカンダリー推力加算部Ｂ１２は、セカンダリーバランス推力Ｆｓに変速比フィードバックセカンダリー推力Ｆｓ＿ｆｂを加算する。これによってセカンダリー推力に変速比フィードバックが適用される。 The gear ratio feedback secondary thrust adding unit B12 adds the gear ratio feedback secondary thrust Fs_fb to the secondary balance thrust Fs. As a result, gear ratio feedback is applied to the secondary thrust.
　変速比フィードバックプライマリー推力加算部Ｂ１３は、プライマリーバランス推力Ｆｐに変速比フィードバックプライマリー推力Ｆｐ＿ｆｂを加算する。これによってプライマリー推力にも変速比フィードバックが適用される。 The transmission ratio feedback primary thrust adding unit B13 adds the transmission ratio feedback primary thrust Fp_fb to the primary balance thrust Fp. As a result, the gear ratio feedback is also applied to the primary thrust.
　さらに変速コントローラー２２は、目標セカンダリー圧Ｐｓと目標プライマリー圧Ｐｐを算出するために、セカンダリー油圧換算部Ｂ１４と、プライマリー油圧換算部Ｂ１５と、を備える。 Furthermore, the transmission controller 22 includes a secondary hydraulic pressure conversion unit B14 and a primary hydraulic pressure conversion unit B15 in order to calculate the target secondary pressure Ps and the target primary pressure Pp.
　セカンダリー油圧換算部Ｂ１４は、変速比フィードバック後のセカンダリー推力から遠心推力、ばね推力を減算後、セカンダリー受圧面積で割ることで、目標セカンダリー圧Ｐｓを算出する。なお遠心推力は、セカンダリープーリー１２の回転速度Ｎｓとあらかじめ定められたセカンダリープーリー遠心推力係数とから算出される。ばね推力は油圧シリンダー１６のストローク距離から算出する。 The secondary hydraulic pressure conversion unit B14 calculates the target secondary pressure Ps by subtracting the centrifugal thrust and the spring thrust from the secondary thrust after the gear ratio feedback and dividing by the secondary pressure receiving area. The centrifugal thrust is calculated from the rotational speed Ns of the secondary pulley 12 and a predetermined secondary pulley centrifugal thrust coefficient. The spring thrust is calculated from the stroke distance of the hydraulic cylinder 16.
　プライマリー油圧換算部Ｂ１５は、変速比フィードバック後のプライマリー推力から遠心推力、ばね推力を減算後、プライマリー受圧面積で割ることで目標プライマリー圧Ｐｐを算出する。なお遠心推力は、プライマリープーリー１１の回転速度Ｎｐとあらかじめ定められたセカンダリープーリー遠心推力係数とから算出される。ばね推力は油圧シリンダー１５のストローク距離から算出される。 The primary hydraulic pressure conversion unit B15 calculates the target primary pressure Pp by subtracting the centrifugal thrust and the spring thrust from the primary thrust after the gear ratio feedback and dividing by the primary pressure receiving area. The centrifugal thrust is calculated from the rotational speed Np of the primary pulley 11 and a predetermined secondary pulley centrifugal thrust coefficient. The spring thrust is calculated from the stroke distance of the hydraulic cylinder 15.
　そして目標セカンダリー推力に基づいてセカンダリー圧ソレノイドが調節される。また、目標プライマリー推力に基づいてプライマリー圧ソレノイドが調節される。この結果、セカンダリープーリー及びプライマリープーリーのそれぞれでＶチェーン伝達トルク容量が確保されるとともに、目標変速比が実現される。 And the secondary pressure solenoid is adjusted based on the target secondary thrust. Further, the primary pressure solenoid is adjusted based on the target primary thrust. As a result, the V chain transmission torque capacity is secured in each of the secondary pulley and the primary pulley, and the target gear ratio is realized.
　図５は、変速比マップの一例を示す図である。 FIG. 5 is a diagram showing an example of the gear ratio map.
　目標プライマリー回転速度算出部Ｂ４は、この変速比マップに、セカンダリー回転速度Ｎｓ(出力回転速度、≒車速ＶＳＰ)とアクセラレーターペダル操作量ＡＰＯとを適用して、目標プライマリー回転速度ＤＮｐを算出する。 The target primary rotation speed calculation unit B4 calculates the target primary rotation speed DNp by applying the secondary rotation speed Ns (output rotation speed, ≈ vehicle speed VSP) and the accelerator pedal operation amount APO to the gear ratio map.
　変速比マップには、図５に示すように最Ｌｏｗ変速比から最Ｈｉｇｈ変速比までの間に、アクセラレーターペダル操作量に応じた複数の変速線が設定されている。なお図５は、図面の煩雑を防ぐために、最Ｌｏｗ変速比線及び最Ｈｉｇｈ変速比線の他には、１本の変速線だけを破線で示す。 In the transmission ratio map, a plurality of transmission lines corresponding to the accelerator pedal operation amount are set between the lowest transmission ratio and the highest transmission ratio as shown in FIG. Note that FIG. 5 shows only one speed change line with a broken line in addition to the lowest speed ratio line and the highest speed ratio line in order to prevent the drawing from being complicated.
　これらの変速線から、セカンダリー回転速度(出力回転速度)が一定であっても、アクセラレーターペダル操作量が小さければ目標プライマリー回転速度(入力回転速度)が小さく、アクセラレーターペダル操作量が大きければ目標プライマリー回転速度(入力回転速度)が大きいことが判る。 From these shift lines, even if the secondary rotation speed (output rotation speed) is constant, if the accelerator pedal operation amount is small, the target primary rotation speed (input rotation speed) is small, and if the accelerator pedal operation amount is large, the target It can be seen that the primary rotation speed (input rotation speed) is large.
　セカンダリー回転速度がＮｓ０、アクセラレーターペダル操作量がＡＰＯ０である場合には、変速線から目標プライマリー回転速度はＤＮｐ０となる。 When the secondary rotation speed is Ns0 and the accelerator pedal operation amount is APO0, the target primary rotation speed is DNp0 from the shift line.
　そして、この場合には、セカンダリー回転速度Ｎｓ０と目標プライマリー回転速度ＤＮｐから、目標変速比はＤｉｐとなる。 In this case, the target gear ratio is Dip from the secondary rotational speed Ns0 and the target primary rotational speed DNp.
　このためセカンダリー回転速度が小さいときに(すなわち低車速のときに)、アクセラレーターペダル操作量が大きいと、目標変速比が最Ｌｏｗ変速比になる。セカンダリー回転速度が大きいときに(すなわち高車速のときに)、アクセラレーターペダル操作量が小さいと、目標変速比が最Ｈｉｇｈ変速比になる。 Therefore, when the secondary rotational speed is low (that is, when the vehicle speed is low), if the accelerator pedal operation amount is large, the target gear ratio becomes the lowest gear ratio. When the secondary rotational speed is high (that is, when the vehicle speed is high), if the accelerator pedal operation amount is small, the target gear ratio becomes the highest gear ratio.
　上述したように、本実施形態で用いられるＣＶＴ４は、無端トルク伝達部材としてＶチェーン１３を使用するチェーン式無段変速機である。すなわちＣＶＴ４は、Ｖチェーン１３によってプライマリープーリー１１の回転トルクをセカンダリープーリー１２に伝達する。Ｖチェーン１３は、引っ張り力によって、プライマリープーリー１１の回転駆動力を、セカンダリープーリーに伝達する。このため、Ｖチェーン１３は、弾性変形して伸びやすい。この伸びを考慮しないと、変速制御の応答が遅れる。 As described above, the CVT 4 used in the present embodiment is a chain type continuously variable transmission that uses the V chain 13 as an endless torque transmission member. That is, the CVT 4 transmits the rotational torque of the primary pulley 11 to the secondary pulley 12 through the V chain 13. The V chain 13 transmits the rotational driving force of the primary pulley 11 to the secondary pulley by a pulling force. For this reason, the V chain 13 is easily elastically deformed and stretched. If this elongation is not taken into account, the response of the shift control is delayed.
　たとえば、目標変速比が最小値に設定される場合、すなわち車両がオーバードライブ状態で走行する場合に、入力トルクが増大してＶチェーン(無端トルク伝達部材)が伸びると、伸び量に応じてセカンダリープーリーの巻き付け径が拡大する。すると、実際の変速比は目標変速比よりもロー側に変化する。このとき、制御ユニットが把握する目標変速比と無段変速機の実変速比とが相違するので、制御ユニットは、実変速比を目標変速比に近づけようとフィードバック制御を実行する。しかしながら、Ｖチェーン(無端トルク伝達部材)が伸びているときには、実変速比を目標変速比に一致させることはできない。それでも、制御ユニットは、フィードバック制御を実行し続ける。すると、フィードバック値がアップシフト側に蓄積される。 For example, when the target gear ratio is set to the minimum value, that is, when the vehicle travels in an overdrive state, if the input torque increases and the V chain (endless torque transmission member) extends, the secondary speed depends on the amount of extension. Pulley winding diameter increases. Then, the actual gear ratio changes to the low side from the target gear ratio. At this time, since the target gear ratio grasped by the control unit is different from the actual gear ratio of the continuously variable transmission, the control unit executes feedback control so as to bring the actual gear ratio closer to the target gear ratio. However, when the V-chain (endless torque transmission member) is extended, the actual gear ratio cannot be matched with the target gear ratio. Nevertheless, the control unit continues to perform feedback control. Then, the feedback value is accumulated on the upshift side.
　フィードバック値が蓄積された状態で、ダウンシフト指令があると、アップシフト側に蓄積されたフィードバック値が解消されるまで、無段変速機のダウンシフト操作が実質的に停止される。すなわち、変速制御の応答が遅れる。このような応答遅れがあると、運転者は違和感を感じる。 If there is a downshift command with the feedback value accumulated, the downshift operation of the continuously variable transmission is substantially stopped until the feedback value accumulated on the upshift side is eliminated. That is, the response of the shift control is delayed. When there is such a response delay, the driver feels uncomfortable.
　このように、Ｖチェーン(無端トルク伝達部材)が伸びていなければ、実現できる目標変速比であっても、Ｖチェーン(無端トルク伝達部材)が伸びているときには、実現できないことがある。 Thus, if the V chain (endless torque transmission member) is not extended, even if the target gear ratio can be realized, it may not be realized when the V chain (endless torque transmission member) is extended.
　そこで上述のように、ＪＰ－２００６－１８９０７９－Ａでは、入力トルクに応じて目標変速比が実現可能な範囲に制限されることで、フィードバック値の蓄積が防止される。しかしながら、それでもまだ不十分であって、精緻な制御ができない、ということが発明者らの知見である。 Therefore, as described above, in JP-2006-189079-A, the target gear ratio is limited to a realizable range in accordance with the input torque, thereby preventing the feedback value from being accumulated. However, it is the inventors' knowledge that it is still insufficient and precise control is not possible.
　すなわち、たとえば停車中にアクセラレーターペダルが踏み込まれて発進するときには、直後に大きな入力トルクが見込まれる。そこで、無端トルク伝達部材(Ｖチェーン)の滑りを防止すべく、予めプーリー推力を上げて無端トルク伝達部材(Ｖチェーン)を締め付けることが一般的に行われる。このような状態では、入力トルクは不変であるが、プーリー推力が上昇しているために、無端トルク伝達部材(Ｖチェーン)の伸び量が大きくなる可能性がある。 That is, for example, when the accelerator pedal is depressed while the vehicle is stopped, a large input torque is expected immediately after. Therefore, in order to prevent the endless torque transmission member (V chain) from slipping, it is generally performed that the pulley thrust is increased in advance to tighten the endless torque transmission member (V chain). In such a state, the input torque remains unchanged, but since the pulley thrust is increased, the amount of elongation of the endless torque transmission member (V chain) may increase.
　そこでこのような場合であっても、無端トルク伝達部材(Ｖチェーン)の伸び量を正確に推定することで、さらに精緻に無段変速機の変速を制御する手法を提案する。具体的な内容は、以下に説明される。 Therefore, even in such a case, a method for controlling the shift of the continuously variable transmission more precisely by accurately estimating the extension amount of the endless torque transmission member (V chain) is proposed. Specific contents will be described below.
　図６は、変速コントローラーの制御内容を示すブロック図である。 FIG. 6 is a block diagram showing the control contents of the speed change controller.
　変速コントローラー２２には、上述のように、目標プライマリー回転速度算出部Ｂ４と、目標変速比設定部Ｂ５と、が含まれているが、さらに詳細に説明すると以下のようになる。 As described above, the speed change controller 22 includes the target primary rotation speed calculation unit B4 and the target speed ratio setting unit B5. The details will be described below.
　目標プライマリー回転速度算出部Ｂ４は、アクセラレーターペダルの操作量ＡＰＯ及びセカンダリープーリー１２の回転速度Ｎｓに基づいて、目標プライマリー回転速度ＤＮｐを算出する。この説明は、前述の説明と重複するが、発明を正確に理解するために、あえて説明する。具体的には、図７に示すような変速比マップにアクセラレーターペダルの操作量ＡＰＯ及びセカンダリープーリー１２の回転速度Ｎｓが適用されることで目標プライマリープーリー回転速度ＤＮｐが求められる。図７では、セカンダリー回転速度がＮｓ１、アクセラレーターペダル操作量がＡＰＯ１の場合である。この場合には、変速線から目標プライマリー回転速度はＤＮｐ１となる。 The target primary rotation speed calculation unit B4 calculates the target primary rotation speed DNp based on the accelerator pedal operation amount APO and the rotation speed Ns of the secondary pulley 12. Although this description overlaps with the previous description, it will be described in order to understand the invention accurately. Specifically, the target primary pulley rotational speed DNp is obtained by applying the accelerator pedal operation amount APO and the rotational speed Ns of the secondary pulley 12 to the gear ratio map as shown in FIG. In FIG. 7, the secondary rotation speed is Ns1, and the accelerator pedal operation amount is APO1. In this case, the target primary rotational speed is DNp1 from the shift line.
　目標変速比算出部Ｂ５１は、目標プライマリー回転速度ＤＮｐをセカンダリープーリー１２の回転速度Ｎｓで除して目標変速比算出値Ｄｉｐ１を算出する。 The target gear ratio calculation unit B51 calculates the target gear ratio calculation value Dip1 by dividing the target primary rotation speed DNp by the rotation speed Ns of the secondary pulley 12.
　チェーン伸び算出部Ｂ５２は、プライマリー入力トルクＴｐ及びセカンダリー推力Ｆｓに基づいてチェーン伸び量ΔＬを求める。具体的には、ｘｚ座標が図８Ａで示され、ｙｚ座標が図８Ｂで示される三次元マップにプライマリー入力トルクＴｐ及びセカンダリー推力Ｆｓが適用されることでチェーン伸び量ΔＬが求められる。なおＶチェーン１３の伸び量ΔＬは、Ｖチェーン１３の張力に依存する。そして図８Ａから判るようにＶチェーン１３の伸び量ΔＬは、プライマリープーリー１１とセカンダリープーリー１２の変速比、セカンダリープーリー１２の可動シーブ推力Ｆｓ、及びプライマリープーリー１１の回転速度Ｎｐが一定であれば、プライマリープーリー１１の入力トルクＴｐが増大するにつれて緩やかに増大する。また図８Ｂから判るようにＶチェーン１３の伸び量ΔＬは、プライマリープーリー１１の入力トルクＴｐと回転速度Ｎｐ、及びプライマリープーリー１１とセカンダリープーリー１２の変速比が一定であれば、セカンダリープーリー１２の可動シーブ推力Ｆｓが大きいほど大きい。 The chain elongation calculating unit B52 obtains a chain elongation amount ΔL based on the primary input torque Tp and the secondary thrust Fs. Specifically, the chain extension amount ΔL is obtained by applying the primary input torque Tp and the secondary thrust Fs to the three-dimensional map whose xz coordinate is shown in FIG. 8A and whose yz coordinate is shown in FIG. 8B. The elongation amount ΔL of the V chain 13 depends on the tension of the V chain 13. As can be seen from FIG. 8A, the extension amount ΔL of the V chain 13 is as long as the transmission ratio of the primary pulley 11 and the secondary pulley 12, the movable sheave thrust Fs of the secondary pulley 12, and the rotation speed Np of the primary pulley 11 are constant. As the input torque Tp of the primary pulley 11 increases, it gradually increases. As can be seen from FIG. 8B, the extension amount ΔL of the V chain 13 is determined by the movement of the secondary pulley 12 if the input torque Tp and the rotational speed Np of the primary pulley 11 and the gear ratio of the primary pulley 11 and the secondary pulley 12 are constant. The larger the sheave thrust Fs, the larger.
　なお、プライマリー入力トルクＴｐは、上述のように、エンジン制御ユニット（ＥＣＵ）より受信するエンジントルクＴｅｎｇと、クラッチの締結状態と、トルクコンバーターのロックアップ状態(すなわち速度比及び流体性能)と、エンジンからプライマリープーリーまでの部分におけるイナーシャトルクと、に基づいて、算出される。プライマリー回転速度Ｎｐは、プライマリー回転速度センサー４２で検出される。セカンダリー推力Ｆｓは、入力トルクから概算した値、前回算出値などを用いればよい。 As described above, the primary input torque Tp includes the engine torque Teng received from the engine control unit (ECU), the clutch engagement state, the torque converter lockup state (that is, the speed ratio and the fluid performance), the engine And the inertia torque in the portion from the primary pulley to the primary pulley. The primary rotation speed Np is detected by the primary rotation speed sensor 42. As the secondary thrust Fs, a value estimated from the input torque, a previously calculated value, or the like may be used.
　変速比上限算出部Ｂ５３は、チェーン伸び量ΔＬに基づいて変速比上限Ｄｉｐ＿ＭＡＸを算出する。具体的には、変速比上限算出部Ｂ５３は、図９に示すような変速比マップにチェーン伸び量ΔＬを適用して変速比上限Ｄｉｐ＿ＭＡＸを求める。たとえば変速比上限Ｄｉｐ＿ＭＡＸは、チェーン伸び量ΔＬがゼロであれば、破線で示される最Ｌｏｗ変速比になり、チェーン伸び量ΔＬが最大値であれば、実線で示される最Ｌｏｗ変速比になる。この間は、チェーン伸び量に比例して、最Ｌｏｗ変速比が設定される。変速比下限算出部Ｂ５４も、同様にチェーン伸び量ΔＬに基づいて変速比下限Ｄｉｐ＿ＭＩＮを算出する。 The gear ratio upper limit calculation unit B53 calculates the gear ratio upper limit Dip_MAX based on the chain elongation amount ΔL. Specifically, the transmission gear ratio upper limit calculation unit B53 obtains the transmission gear ratio upper limit Dip_MAX by applying the chain extension amount ΔL to the transmission gear ratio map as shown in FIG. For example, the gear ratio upper limit Dip_MAX is the lowest gear ratio indicated by a broken line if the chain elongation amount ΔL is zero, and the lowest gear ratio indicated by a solid line if the chain elongation amount ΔL is the maximum value. During this time, the lowest gear ratio is set in proportion to the chain elongation. Similarly, the transmission gear ratio lower limit calculation unit B54 calculates the transmission gear ratio lower limit Dip_MIN based on the chain elongation amount ΔL.
　目標変速比設定部Ｂ５５は、目標変速比算出値Ｄｉｐ１が変速比上限Ｄｉｐ＿ＭＡＸよりも大きいときには、変速比上限Ｄｉｐ＿ＭＡＸを目標変速比Ｄｉｐとして設定する。目標変速比設定部Ｂ５５は、目標変速比算出値Ｄｉｐ１が変速比下限Ｄｉｐ＿ＭＩＮよりも小さいときには、変速比下限Ｄｉｐ＿ＭＩＮを目標変速比Ｄｉｐとして設定する。目標変速比設定部Ｂ５５は、目標変速比算出値Ｄｉｐ１が変速比上限Ｄｉｐ＿ＭＡＸ以下であって、かつ変速比下限Ｄｉｐ＿ＭＩＮ以上であれば、目標変速比算出値Ｄｉｐ１を目標変速比Ｄｉｐとして設定する。 The target gear ratio setting unit B55 sets the gear ratio upper limit Dip_MAX as the target gear ratio Dip when the target gear ratio calculated value Dip1 is larger than the gear ratio upper limit Dip_MAX. The target speed ratio setting unit B55 sets the speed ratio lower limit Dip_MIN as the target speed ratio Dip when the target speed ratio calculated value Dip1 is smaller than the speed ratio lower limit Dip_MIN. The target speed ratio setting unit B55 sets the target speed ratio calculated value Dip1 as the target speed ratio Dip if the target speed ratio calculated value Dip1 is equal to or lower than the speed ratio upper limit Dip_MAX and equal to or higher than the speed ratio lower limit Dip_MIN.
　図７では、目標変速比算出値Ｄｉｐ１が変速比下限Ｄｉｐ＿ＭＩＮよりも小さかったので、変速比下限Ｄｉｐ＿ＭＩＮが目標変速比Ｄｉｐとして設定された。 In FIG. 7, since the target speed ratio calculated value Dip1 is smaller than the speed ratio lower limit Dip_MIN, the speed ratio lower limit Dip_MIN is set as the target speed ratio Dip.
　なお変速比上限Ｄｉｐ＿ＭＡＸ及び変速比下限Ｄｉｐ＿ＭＩＮは、チェーン長Ｌ、プーリーストッパーの位置などの緒元よって決まる。チェーン長Ｌは、チェーンに作用する張力によって決まるので、チェーン長Ｌは、入力トルクＴｐ、プライマリー推力Ｆｐ、セカンダリー推力Ｆｓ、遠心項(プライマリー回転速度Ｎｐ及びセカンダリー回転速度Ｎｓに基づいて算出できる)によって求まる。このチェーン長Ｌとストッパーの位置とによって変速比上限Ｄｉｐ＿ＭＡＸ及び変速比下限Ｄｉｐ＿ＭＩＮが決められる。そこで、変速比上限算出部Ｂ５３や変速比下限算出部Ｂ５４において、これらの算出結果をマップに設定しておき、各入力に対応した変速比上限Ｄｉｐ＿ＭＡＸ・変速比下限Ｄｉｐ＿ＭＩＮを算出してもよい。たとえば最Ｈｉｇｈ変速比に対応するストッパーがプライマリープーリー側に設けられている場合には、チェーンが伸びると最Ｌｏｗ変速比はＬｏｗシフトする。各入力のうち入力トルクＴｐのみが上昇した場合には、チェーンにかかる張力が上昇してチェーンが伸びるので、最Ｈｉｇｈ変速比がＬｏｗシフトする。また各入力のうちプライマリー回転速度Ｎｐ及びセカンダリー回転速度Ｎｓのみが上昇した場合には、チェーンにかかる張力が上昇してチェーンが伸びるので、最Ｈｉｇｈ変速比がＬｏｗシフトする。さらに各入力のうちセカンダリー推力Ｆｓ及びプライマリー推力Ｆｐのみが上昇した場合には、チェーンにかかる張力が上昇してチェーンが伸びるため、最Ｈｉｇｈ変速比がＬｏｗシフトする。 The gear ratio upper limit Dip_MAX and the gear ratio lower limit Dip_MIN are determined by specifications such as the chain length L and the position of the pulley stopper. Since the chain length L is determined by the tension acting on the chain, the chain length L is determined by the input torque Tp, the primary thrust Fp, the secondary thrust Fs, and the centrifugal term (which can be calculated based on the primary rotational speed Np and the secondary rotational speed Ns). I want. The gear ratio upper limit Dip_MAX and the gear ratio lower limit Dip_MIN are determined by the chain length L and the position of the stopper. Therefore, the transmission ratio upper limit calculation unit B53 and the transmission ratio lower limit calculation unit B54 may set these calculation results in a map, and calculate the transmission ratio upper limit Dip_MAX and the transmission ratio lower limit Dip_MIN corresponding to each input. For example, when a stopper corresponding to the highest gear ratio is provided on the primary pulley side, the lowest gear ratio shifts low when the chain extends. When only the input torque Tp of each input is increased, the tension applied to the chain is increased and the chain is extended, so that the highest gear ratio is shifted low. When only the primary rotational speed Np and the secondary rotational speed Ns increase among the inputs, the tension applied to the chain is increased and the chain is extended, so that the highest gear ratio is shifted low. Furthermore, when only the secondary thrust Fs and the primary thrust Fp of each input are increased, the tension applied to the chain is increased and the chain is extended, so that the highest gear ratio is shifted Low.
　図１０は、本実施形態による作用効果を説明するタイムチャートである。 FIG. 10 is a time chart for explaining operational effects according to the present embodiment.
　時刻ｔ１１でアクセラレーターペダルが踏み込まれると(図１０(Ａ))、直後に大きな入力トルクが見込まれる。そこで、無端トルク伝達部材(Ｖチェーン)の滑りを防止するように、プーリー推力が大きくなる(図１０(Ｃ))。これによりＶチェーンの張力が大きくなりＶチェーンが伸びる(図１０(Ｄ))。 When the accelerator pedal is depressed at time t11 (FIG. 10A), a large input torque is expected immediately after. Therefore, the pulley thrust is increased so as to prevent the endless torque transmitting member (V chain) from slipping (FIG. 10C). As a result, the tension of the V chain is increased and the V chain is extended (FIG. 10D).
　このとき本実施形態では、プライマリープーリーに入力されるトルクＴｐ及びセカンダリープーリーに作用する推力Ｆｓに基づいてチェーン長Ｌが算出される。このとき、セカンダリープーリーに作用する推力Ｆｓが大きいほど、チェーン長Ｌが長く算出される。そして、これに合わせて目標変速比の制限値が設定されるので、時刻ｔ１１で目標変速比の制限値が変更される(図１０(Ｅ))。 At this time, in this embodiment, the chain length L is calculated based on the torque Tp input to the primary pulley and the thrust Fs acting on the secondary pulley. At this time, the greater the thrust Fs acting on the secondary pulley, the longer the chain length L is calculated. Since the target speed ratio limit value is set accordingly, the target speed ratio limit value is changed at time t11 (FIG. 10E).
　一方、比較形態のように、プライマリープーリーに入力されるトルクＴｐにのみ基づいて目標変速比の制限値が設定される場合は、トルクＴｐの上昇に合わせて、目標変速比の制限値も変化する(図１０(Ｅ))。したがってこのようにしては、目標変速比が無用に制限されることとなり、実際に採用できる変速比幅が不当に狭められてしまう可能性があった。 On the other hand, when the target speed ratio limit value is set based only on the torque Tp input to the primary pulley as in the comparative embodiment, the target speed ratio limit value also changes as the torque Tp increases. (FIG. 10 (E)). Therefore, in this way, the target gear ratio is unnecessarily limited, and the gear ratio width that can be actually used may be unduly narrowed.
　これに対して本実施形態によれば、時刻ｔ１１で目標変速比の制限値が変更されるので(図１０(Ｅ))、目標変速比が無用に制限されることがなく、実際に採用しうる範囲で最大の変速比幅が確保される。 On the other hand, according to the present embodiment, since the limit value of the target speed ratio is changed at time t11 (FIG. 10E), the target speed ratio is not limited unnecessarily and is actually used. The maximum speed ratio range is ensured within the possible range.
　また目標変速比の下限値が算出される場合においても、ホイルスピン対応時やフェールセーフ時における入力トルクと独立した推力上昇にも対応できることとなり、目標変速比と実変速比の乖離が防止され、フィードバック制御のフィードバック値の蓄積が回避されるのである。 In addition, even when the lower limit value of the target gear ratio is calculated, it is possible to respond to a thrust increase independent of the input torque at the time of wheel spin correspondence or fail safe, and the deviation between the target gear ratio and the actual gear ratio is prevented, Accumulation of feedback values in feedback control is avoided.
　さらに本実施形態では、入力トルクのみでなく、推力に応じたチェーン伸び量が推定されて変速比上限Ｄｉｐ＿ＭＡＸ及び変速比下限Ｄｉｐ＿ＭＩＮが算出されるので、より適切な変速比幅が確保される。したがって、より緻密に目標変速比と実変速比の乖離によるフィードバック制御のフィードバック値の蓄積が回避される。 Furthermore, in the present embodiment, not only the input torque but also the chain extension amount corresponding to the thrust is estimated and the speed ratio upper limit Dip_MAX and the speed ratio lower limit Dip_MIN are calculated, so that a more appropriate speed ratio width is secured. Therefore, accumulation of the feedback value of the feedback control due to the difference between the target speed ratio and the actual speed ratio is avoided more precisely.
　さらにまた本実施形態では、発進時の推力増大補正に応じてチェーン伸び量が大きく推定されることによって、高い変速比が求められる発進時において変速比上限Ｄｉｐ＿ＭＡＸが引き上げられる。 Furthermore, in the present embodiment, the gear ratio upper limit Dip_MAX is raised at the time of start where a high gear ratio is required by estimating the chain extension amount in accordance with the thrust increase correction at the time of start.
　目標変速比が最小値に設定される場合、すなわち車両がオーバードライブ状態で走行する場合に、入力トルクが増大してＶチェーン(無端トルク伝達部材)が伸びると、伸び量に応じてセカンダリープーリーの巻き付け径が拡大する。すると、実際の変速比は目標変速比よりもロー側に変化する。この結果、制御ユニットが把握する目標変速比と無段変速機の実変速比とが相違する。すると、制御ユニットは、実変速比を目標変速比に近づけようとフィードバック制御を実行する。本実施形態が適用されないと、Ｖチェーン(無端トルク伝達部材)が伸びているときには、実変速比が目標変速比に一致させることはできないことがある。それでも、制御ユニットは、フィードバック制御を実行し続ける。すると、フィードバック値がアップシフト側に蓄積されてしまう。フィードバック値が蓄積された状態で、ダウンシフト指令があると、アップシフト側に蓄積されたフィードバック値が解消されるまで、無段変速機のダウンシフト操作が実質的に停止する。すなわち、変速制御の応答性が低下する。このような応答遅れがあると、運転者は違和感を感じる。 When the target gear ratio is set to the minimum value, that is, when the vehicle travels in an overdrive state, if the input torque increases and the V chain (endless torque transmission member) extends, the secondary pulley will The winding diameter increases. Then, the actual gear ratio changes to the low side from the target gear ratio. As a result, the target speed ratio ascertained by the control unit is different from the actual speed ratio of the continuously variable transmission. Then, the control unit executes feedback control so as to bring the actual speed ratio closer to the target speed ratio. If this embodiment is not applied, when the V chain (endless torque transmission member) is extended, the actual gear ratio may not be matched with the target gear ratio. Nevertheless, the control unit continues to perform feedback control. Then, the feedback value is accumulated on the upshift side. If a downshift command is issued in a state where the feedback value is accumulated, the downshift operation of the continuously variable transmission is substantially stopped until the feedback value accumulated on the upshift side is eliminated. That is, the responsiveness of the shift control is lowered. When there is such a response delay, the driver feels uncomfortable.
　またセカンダリープーリーの可動シーブが広がってストッパーに当接した状態、すなわちＶチェーン(無端トルク伝達部材)のセカンダリープーリーへの巻き付け半径が固定された状態で、Ｖチェーン(無端トルク伝達部材)が伸びると、伸び量に応じてプライマリープーリーの巻き付け径が拡大する。すると、実際の変速比は目標変速比よりもハイ側に変化する。この結果、制御ユニットが把握する目標変速比と無段変速機の実変速比とが相違する。すると、制御ユニットは、実変速比を目標変速比に近づけようとフィードバック制御を実行する。本実施形態が適用されないと、Ｖチェーン(無端トルク伝達部材)が伸びているときには、実変速比が目標変速比に一致させることはできないことがある。それでも、制御ユニットは、フィードバック制御を実行し続ける。すると、フィードバック値がダウンシフト側に蓄積されてしまう。フィードバック値が蓄積された状態で、アップシフト指令があると、ダウンシフト側に蓄積されたフィードバック値が解消されるまで、無段変速機のアップシフト操作が実質的に停止する。すなわち、変速制御の応答性が低下する。このような応答遅れがあると、運転者は違和感を感じる。 When the movable sheave of the secondary pulley expands and abuts against the stopper, that is, when the winding radius of the V chain (endless torque transmission member) around the secondary pulley is fixed, the V chain (endless torque transmission member) extends. The winding diameter of the primary pulley increases according to the amount of elongation. Then, the actual gear ratio changes to a higher side than the target gear ratio. As a result, the target speed ratio ascertained by the control unit is different from the actual speed ratio of the continuously variable transmission. Then, the control unit executes feedback control so as to bring the actual speed ratio closer to the target speed ratio. If this embodiment is not applied, when the V chain (endless torque transmission member) is extended, the actual gear ratio may not be matched with the target gear ratio. Nevertheless, the control unit continues to perform feedback control. Then, the feedback value is accumulated on the downshift side. When an upshift command is issued in a state where the feedback value is accumulated, the upshift operation of the continuously variable transmission is substantially stopped until the feedback value accumulated on the downshift side is eliminated. That is, the responsiveness of the shift control is lowered. When there is such a response delay, the driver feels uncomfortable.
　これに対して本実施形態では、プライマリープーリーに入力されるトルクＴｐ及びセカンダリープーリーに作用する推力Ｆｓに基づいてチェーン長Ｌを算出して、これに合わせて目標変速比の制限値を設定する。このようにすることで、目標変速比の制限値が適切に変更される。したがって、実現できない目標変速比が設定されないので、フィードバック値が蓄積されることがなく、変速制御の応答性の低下を防止でき、運転者に違和感を感じさせないのである。 On the other hand, in this embodiment, the chain length L is calculated based on the torque Tp input to the primary pulley and the thrust Fs acting on the secondary pulley, and the limit value of the target gear ratio is set according to this. By doing so, the limit value of the target gear ratio is appropriately changed. Therefore, since a target speed ratio that cannot be realized is not set, a feedback value is not accumulated, a reduction in response of the speed change control can be prevented, and the driver does not feel uncomfortable.
　（第２実施形態）
　第１実施形態では、チェーンに作用する張力は、入力トルクＴｐのみならず、プーリー推力にも影響を受けるという技術知見に鑑み、プライマリー入力トルクＴｐ及びセカンダリー推力Ｆｓに基づいてチェーン伸び量ΔＬを求めた。 (Second Embodiment)
In the first embodiment, in view of technical knowledge that the tension acting on the chain is affected not only by the input torque Tp but also by the pulley thrust, the chain elongation amount ΔL is obtained based on the primary input torque Tp and the secondary thrust Fs. It was.
　しかしながら、チェーンに作用する張力は、プーリーの回転速度にも影響を受ける。すなわちプーリーの回転速度が大きいほど、遠心力が大きく作用して、チェーンに作用する張力が大きくなる。そこで本実施形態では、プライマリー入力トルクＴｐ及びプライマリー回転速度Ｎｓに基づいてチェーン伸び量ΔＬが求められた。 However, the tension acting on the chain is also affected by the rotational speed of the pulley. That is, the greater the rotational speed of the pulley, the greater the centrifugal force acts and the greater the tension acting on the chain. Therefore, in this embodiment, the chain elongation amount ΔL is obtained based on the primary input torque Tp and the primary rotational speed Ns.
　ここで図１１を参照して、プライマリー入力トルクＴｐが一定であっても、プライマリー回転速度Ｎｓが異なる場合について説明する。 Here, a case where the primary rotational speed Ns is different even when the primary input torque Tp is constant will be described with reference to FIG.
　トルクコンバーターのロックアップクラッチがオン(締結状態)の場合には、エンジントルクがＣＶＴへの入力トルクになる。エンジントルクＴｅは、アクセラレーターペダル操作量(吸気スロットル開度)ＡＰＯ、及びエンジン回転速度Ｎｅごとに所定の値となり、図１１のように表される。所定のアクセラレーターペダル操作量ＡＰＯのときに、エンジントルクがＴｅ０であっても、エンジン回転速度がＮｅ２の場合とＮｅ３の場合とがある。またアクセラレーターペダル操作量ＡＰＯが変われば(大きくなれば)、エンジントルクがＴｅ０であっても、エンジン回転速度がＮｅ１の場合がある。 When the torque converter lockup clutch is on (engaged), the engine torque becomes the input torque to the CVT. The engine torque Te has a predetermined value for each accelerator pedal operation amount (intake throttle opening) APO and engine rotational speed Ne, and is expressed as shown in FIG. Even when the engine torque is Te0 at a predetermined accelerator pedal operation amount APO, there are cases where the engine rotation speed is Ne2 and Ne3. If the accelerator pedal operation amount APO changes (becomes larger), the engine speed may be Ne1 even if the engine torque is Te0.
　さらに、トルクコンバーターのロックアップクラッチがオフ(解放状態)の場合においても、エンジン回転速度Ｎｅ、速度比(タービン回転速度をエンジン回転速度で割ったもの)から定まるトルク比と容量係数の状況によっては、入力トルクが同じであっても、入力回転速度が変わることがある。 Furthermore, even when the lock-up clutch of the torque converter is off (disengaged), depending on the situation of the torque ratio and capacity coefficient determined from the engine speed Ne and speed ratio (turbine speed divided by engine speed) Even if the input torque is the same, the input rotation speed may change.
　このようなことから、プライマリー入力トルクＴｐが一定であっても、プライマリー回転速度Ｎｓが異なる場合が存在する。 For this reason, even when the primary input torque Tp is constant, the primary rotational speed Ns may be different.
　図１２は、第２実施形態における変速コントローラーの制御内容を示すブロック図である。 FIG. 12 is a block diagram showing the control contents of the speed change controller in the second embodiment.
　なお以下では前述と同様の機能を果たす部分には同一の符号を付して重複する説明を適宜省略する。 In the following, parts that perform the same functions as those described above are given the same reference numerals, and redundant descriptions are omitted as appropriate.
　上記技術知見に鑑み、本実施形態では、チェーン伸び算出部Ｂ５２１において、プライマリー入力トルクＴｐ及びプライマリー回転速度Ｎｓに基づいてチェーン伸び量ΔＬが求められる。具体的には、ｘｚ座標が図１３Ａで示され、ｙｚ座標が図１３Ｂで示される三次元マップにプライマリー入力トルクＴｐ及びプライマリー回転速度Ｎｓが適用されてチェーン伸び量ΔＬが求められる。図１３Ａは、図８Ａと同様である。図１３Ｂから判るように、Ｖチェーン１３の伸び量ΔＬは、プライマリープーリー１１への入力トルク、セカンダリープーリー１２の可動シーブ推力、及びプライマリープーリー１１が一定であれば、プライマリープーリー１１の回転速度Ｎｐが大きいほど大きい。 In view of the above technical knowledge, in this embodiment, the chain elongation calculation unit B521 calculates the chain elongation amount ΔL based on the primary input torque Tp and the primary rotational speed Ns. Specifically, the chain input amount ΔL is obtained by applying the primary input torque Tp and the primary rotational speed Ns to the three-dimensional map whose xz coordinate is shown in FIG. 13A and whose yz coordinate is shown in FIG. 13B. FIG. 13A is similar to FIG. 8A. As can be seen from FIG. 13B, the extension amount ΔL of the V chain 13 is determined by the input torque to the primary pulley 11, the movable sheave thrust of the secondary pulley 12, and the rotation speed Np of the primary pulley 11 if the primary pulley 11 is constant. Larger is bigger.
　図１４は、第２実施形態による作用効果を説明するタイムチャートである。 FIG. 14 is a time chart for explaining operational effects according to the second embodiment.
　時刻ｔ２１でアクセラレーターペダルが踏み込まれると(図１４(Ａ))、それに伴ってプライマリープーリーに入力されるトルクＴｐが大きくなり、時刻ｔ２２以降は一定になるが(図１４(Ｂ))、プライマリー回転速度Ｎｐは時刻ｔ２２以降も大きくなることがある(図１４(Ｃ))。具体的な運転シーンを考えると、たとえば路面勾配が変化したために、入力トルクＴｐが変わらなくとも、車速が上昇する場合などである。 When the accelerator pedal is depressed at time t21 (FIG. 14 (A)), the torque Tp input to the primary pulley increases accordingly and becomes constant after time t22 (FIG. 14 (B)). The rotational speed Np may increase after time t22 (FIG. 14C). Considering a specific driving scene, for example, when the road surface gradient changes, the vehicle speed increases even if the input torque Tp does not change.
　このような場合に、本実施形態では、プライマリープーリーに入力されるトルクＴｐ及びプライマリープーリー１１の回転速度Ｎｐに基づいてチェーン伸び量ΔＬが算出される。このとき、プライマリープーリー１１の回転速度Ｎｐが大きいほど、チェーン伸び量ΔＬが長く算出される。そして、これに合わせて目標変速比の制限値が設定されるので、時刻ｔ２２以降も目標変速比の制限値が変更される(図１４(Ｅ))。 In such a case, in this embodiment, the chain elongation amount ΔL is calculated based on the torque Tp input to the primary pulley and the rotational speed Np of the primary pulley 11. At this time, the larger the rotation speed Np of the primary pulley 11, the longer the chain elongation amount ΔL is calculated. Since the target speed ratio limit value is set accordingly, the target speed ratio limit value is also changed after time t22 (FIG. 14E).
　一方、比較形態のようにプライマリープーリーに入力されるトルクＴｐにのみ基づいて目標変速比の制限値が設定される場合は、時刻ｔ２２以降は目標変速比の制限値が変更されない(図１４(Ｅ))。したがってこのようにしては、目標変速比が無用に制限されることとなり、実際に採用できる変速比幅が不当に狭められてしまう可能性があった。 On the other hand, when the target speed ratio limit value is set only based on the torque Tp input to the primary pulley as in the comparative embodiment, the target speed ratio limit value is not changed after time t22 (FIG. 14E )). Therefore, in this way, the target gear ratio is unnecessarily limited, and the gear ratio width that can be actually used may be unduly narrowed.
　これに対して本実施形態によれば、時刻ｔ２２以降も目標変速比の制限値が変更されるので、目標変速比が無用に制限されることがなく、実際に採用しうる範囲で最大の変速比幅が確保される。 On the other hand, according to the present embodiment, the target speed ratio limit value is changed after time t22, so that the target speed ratio is not unnecessarily limited, and the maximum speed change within the range that can be actually employed. A specific width is secured.
　また、最Ｈｉｇｈ変速比付近では同一のコーストトルクであっても車速によってプライマリープーリー１１の回転速度が異なるので、比較形態ではチェーンが最も伸びる最大回転速度が常に入力される前提で変速比下限Ｄｉｐ＿ＭＩＮが設定される必要があった。一方、本実施形態では、回転速度に応じて変速比下限Ｄｉｐ＿ＭＩＮが変化させられるので、回転速度の小さな領域で目標変速比が下げられる。以上のことから、本実施形態によれば、より適切な変速比上限Ｄｉｐ＿ＭＡＸが指示され、実際に採用しうる範囲で最大の変速比幅が確保されるのである。 Further, since the rotational speed of the primary pulley 11 varies depending on the vehicle speed even in the vicinity of the highest gear ratio, even if the coast torque is the same, in the comparative form, the gear ratio lower limit Dip_MIN is set on the premise that the maximum rotational speed at which the chain extends most is always input. Needed to be set. On the other hand, in the present embodiment, since the speed ratio lower limit Dip_MIN is changed according to the rotational speed, the target speed ratio is lowered in a region where the rotational speed is small. From the above, according to the present embodiment, a more appropriate speed ratio upper limit Dip_MAX is instructed, and the maximum speed ratio width is secured in a range that can be actually used.
　さらに本実施形態では、入力トルクのみでなく、回転速度に応じたチェーン伸び量が推定されて変速比上限Ｄｉｐ＿ＭＡＸ及び変速比下限Ｄｉｐ＿ＭＩＮが算出される。このようにすることで、より適切な変速比幅が確保される。したがって、より緻密に目標変速比と実変速比の乖離によるフィードバック制御のフィードバック値の蓄積が回避されるのである。 Further, in the present embodiment, not only the input torque but also the chain extension amount corresponding to the rotational speed is estimated, and the gear ratio upper limit Dip_MAX and the gear ratio lower limit Dip_MIN are calculated. By doing so, a more appropriate gear ratio range is ensured. Therefore, accumulation of the feedback value of the feedback control due to the difference between the target speed ratio and the actual speed ratio is avoided more precisely.
　さらにまた本実施形態では、入力回転速度に応じてチェーン伸び量が推定されることによって、低回転速度の最Ｈｉｇｈ変速比での走行時に変速比下限Ｄｉｐ＿ＭＩＮが引き下げられる。この結果、エンジンが低回転速度で走行でき、燃費が向上するという効果が得られるのである。 Furthermore, in the present embodiment, by estimating the chain elongation amount according to the input rotational speed, the speed ratio lower limit Dip_MIN is lowered when traveling at the highest speed gear ratio at a low rotational speed. As a result, the engine can run at a low rotational speed, and the effect of improving fuel efficiency can be obtained.
　以上、本発明の実施形態について説明したが、上記実施形態は本発明の適用例の一部を示したに過ぎず、本発明の技術的範囲を上記実施形態の具体的構成に限定する趣旨ではない。 The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.
　たとえば、第１実施形態と第２実施形態とを組み合わせて、チェーン伸び算出部において、プライマリー入力トルクＴｐ、セカンダリー推力Ｆｓ及びプライマリー回転速度Ｎｓに基づいてチェーン伸び量ΔＬが求められてもよい。この場合は、チェーン伸び量ΔＬ、プライマリー入力トルクＴｐ、セカンダリー推力Ｆｓ及びプライマリー回転速度Ｎｓを軸とする４次元マップに、プライマリー入力トルクＴｐ、セカンダリー推力Ｆｓ及びプライマリー回転速度Ｎｓが適用されてチェーン伸び量ΔＬが求められればよい。 For example, by combining the first embodiment and the second embodiment, the chain elongation calculation unit may obtain the chain elongation amount ΔL based on the primary input torque Tp, the secondary thrust Fs, and the primary rotational speed Ns. In this case, the chain elongation is obtained by applying the primary input torque Tp, the secondary thrust Fs, and the primary rotational speed Ns to the four-dimensional map having the chain elongation amount ΔL, the primary input torque Tp, the secondary thrust Fs, and the primary rotational speed Ns as axes. The amount ΔL may be obtained.
　たとえば、上記説明においては、無端トルク伝達部材としてＶチェーンが例示されたが、これには限定されない。たとえばゴムその他の樹脂製のベルトであってもよい。セカンダリープーリーに作用して動力を伝達するときに弾性変形による伸びが発生するものに適用可能である。 For example, in the above description, the V chain is exemplified as the endless torque transmitting member, but the present invention is not limited to this. For example, rubber or other resin belts may be used. The present invention can be applied to a structure in which elongation due to elastic deformation occurs when power is transmitted by acting on a secondary pulley.
　また上記説明においては、プーリー推力としてセカンダリー推力に基づいてチェーン伸び量が算出されたが、プライマリー推力に基づいて算出されてもよい。 In the above description, the chain elongation amount is calculated based on the secondary thrust as the pulley thrust, but may be calculated based on the primary thrust.
　さらに上記説明においては、プーリー回転速度としてプライマリー回転速度に基づいてチェーン伸び量が算出されたが、セカンダリー回転速度に基づいて算出されてもよい。 Furthermore, in the above description, the chain elongation amount is calculated based on the primary rotation speed as the pulley rotation speed, but may be calculated based on the secondary rotation speed.
　さらにまた、上記実施形態では、プライマリー入力トルクＴｐ及びセカンダリー推力Ｆｓに基づいて、またはプライマリー入力トルクＴｐ及びプライマリー回転速度Ｎｓに基づいて、一旦チェーンの伸び量ΔＬが算出されて変速比上限Ｄｉｐ＿ＭＡＸ及び変速比下限Ｄｉｐ＿ＭＩＮが求められた。これには限られず、予めマップなどを準備しておいて、プライマリー入力トルクＴｐ、セカンダリー推力Ｆｓ及びプライマリー回転速度Ｎｓから変速比上限Ｄｉｐ＿ＭＡＸ及び変速比下限Ｄｉｐ＿ＭＩＮが直接求められてもよい。 Furthermore, in the above embodiment, the chain elongation amount ΔL is once calculated based on the primary input torque Tp and the secondary thrust Fs, or based on the primary input torque Tp and the primary rotational speed Ns, and the speed ratio upper limit Dip_MAX and the speed change The lower limit Dip_MIN was determined. The present invention is not limited to this, and a map or the like may be prepared in advance, and the gear ratio upper limit Dip_MAX and the gear ratio lower limit Dip_MIN may be directly obtained from the primary input torque Tp, the secondary thrust Fs, and the primary rotation speed Ns.
　本願は、２０１１年１月１７日に日本国特許庁に出願された特願２０１１－００６６５３に基づく優先権を主張し、この出願の全ての内容は参照により本明細書に組み込まれる。
  This application claims priority based on Japanese Patent Application No. 2011-006653 filed with the Japan Patent Office on January 17, 2011, the entire contents of which are incorporated herein by reference.

Claims (7)

  1. 　一対のプーリーに掛け回された無端トルク伝達部材を介して前記一対のプーリー間で変速する無段変速機の変速制御装置において、
    　変速機の目標変速比を算出する目標変速比算出部と、
    　プーリー推力及びプーリー回転速度の少なくともいずれか一方と、変速機に入力されるトルクと、に基づいて目標変速比の制限値を算出する制限値算出部と、
    　前記目標変速比算出部で算出された目標変速比算出値が前記制限値を越えれば、前記制限値を目標変速比として設定し、目標変速比算出値が前記制限値を越えなければ、目標変速比算出値を目標変速比として設定する目標変速比設定部と、
    を有する無段変速機の変速制御装置。     In a transmission control device for a continuously variable transmission that shifts between the pair of pulleys via an endless torque transmission member wound around the pair of pulleys,
    A target gear ratio calculation unit for calculating a target gear ratio of the transmission;
    A limit value calculation unit that calculates a limit value of the target gear ratio based on at least one of pulley thrust and pulley rotation speed and torque input to the transmission;
    If the target speed ratio calculation value calculated by the target speed ratio calculation unit exceeds the limit value, the limit value is set as the target speed ratio, and if the target speed ratio calculation value does not exceed the limit value, the target speed ratio A target gear ratio setting unit for setting the ratio calculation value as a target gear ratio;
    A transmission control device for a continuously variable transmission.
  2. 　請求項１に記載の無段変速機の変速制御装置において、
    　前記制限値算出部は、プーリー推力及びプーリー回転速度の少なくとも一方と入力トルクとに基づいて、前記無端トルク伝達部材の伸び量を算出し、その伸び量に基づいて、目標変速比の制限値を算出する、
    無段変速機の変速制御装置。     The transmission control device for a continuously variable transmission according to claim 1,
    The limit value calculation unit calculates an extension amount of the endless torque transmission member based on at least one of a pulley thrust and a pulley rotation speed and an input torque, and calculates a limit value of the target gear ratio based on the extension amount. calculate,
    A transmission control device for a continuously variable transmission.
  3. 　請求項２に記載の無段変速機の変速制御装置において、
    　前記制限値算出部は、前記無端トルク伝達部材の伸び量に基づいて、目標変速比の上限値及び下限値を算出し、
    　前記目標変速比設定部は、前記目標変速比算出値が前記上限値よりも大きいときには、その上限値を目標変速比として設定し、目標変速比算出値が前記下限値よりも小さいときには、その下限値を目標変速比として設定し、目標変速比算出値が前記上限値以下、かつ前記下限値以上であるときには、目標変速比算出値を目標変速比として設定する、
    無段変速機の変速制御装置。     The transmission control device for a continuously variable transmission according to claim 2,
    The limit value calculation unit calculates an upper limit value and a lower limit value of the target gear ratio based on the extension amount of the endless torque transmission member,
    The target speed ratio setting unit sets the upper limit value as a target speed ratio when the target speed ratio calculated value is larger than the upper limit value, and sets the lower limit value when the target speed ratio calculated value is smaller than the lower limit value. A value is set as the target speed ratio, and when the target speed ratio calculation value is not more than the upper limit value and not less than the lower limit value, the target speed ratio calculation value is set as the target speed ratio.
    A transmission control device for a continuously variable transmission.
  4. 　請求項２又は請求項３に記載の無段変速機の変速制御装置において、
    　前記制限値算出部は、プーリー推力が大きいほど、前記無端トルク伝達部材の伸び量を大きく算出する、
    無段変速機の変速制御装置。     The transmission control device for a continuously variable transmission according to claim 2 or claim 3,
    The limit value calculation unit calculates the elongation amount of the endless torque transmission member to be larger as the pulley thrust is larger.
    A transmission control device for a continuously variable transmission.
  5. 　請求項２から請求項４までのいずれか１項に記載の無段変速機の変速制御装置において、
    　前記制限値算出部は、発進時には、発進以外のときと比較して、前記無端トルク伝達部材の伸び量を大きく算出する、
    無段変速機の変速制御装置。     The transmission control device for a continuously variable transmission according to any one of claims 2 to 4,
    The limit value calculation unit calculates a large amount of elongation of the endless torque transmission member at the time of starting, as compared to a time other than starting.
    A transmission control device for a continuously variable transmission.
  6. 　請求項２から請求項５までのいずれか１項に記載の無段変速機の変速制御装置において、
    　前記制限値算出部は、プーリー回転速度が大きいほど、前記無端トルク伝達部材の伸び量を大きく算出する、
    無段変速機の変速制御装置。     The transmission control apparatus for a continuously variable transmission according to any one of claims 2 to 5,
    The limit value calculation unit calculates the elongation amount of the endless torque transmission member to be larger as the pulley rotation speed is larger.
    A transmission control device for a continuously variable transmission.
  7. 　請求項２から請求項６までのいずれか１項に記載の無段変速機の変速制御装置において、
    　前記制限値算出部は、下り坂を走行するときは、下り坂以外を走行するときと比較して、前記無端トルク伝達部材の伸び量を大きく算出する、
    無段変速機の変速制御装置。
     
          The transmission control device for a continuously variable transmission according to any one of claims 2 to 6,
    The limit value calculating unit calculates a large amount of elongation of the endless torque transmitting member when traveling on a downhill as compared to when traveling on other than a downhill,
    A transmission control device for a continuously variable transmission.

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