CN111201390B

CN111201390B - Double-clutch type speed changer

Info

Publication number: CN111201390B
Application number: CN201880065833.2A
Authority: CN
Inventors: 冈本壮史
Original assignee: Isuzu Motors Ltd
Current assignee: Isuzu Motors Ltd
Priority date: 2017-10-12
Filing date: 2018-10-12
Publication date: 2021-09-28
Anticipated expiration: 2038-10-12
Also published as: WO2019074085A1; CN111201390A; JP2019074103A

Abstract

In a twin clutch transmission according to the present invention, when a shift is performed from a first predetermined shift speed, which is a shift speed in which power is transmitted from a drive source to an output shaft via a second input shaft, a first countershaft, and a second countershaft, to the first countershaft, the coupling between the first countershaft and the second countershaft is released, and power is not transmitted from the drive source to the first countershaft, and when a state change is performed in which power is transmitted from the drive source to the first countershaft via the first input shaft and the second countershaft, a second clutch is temporarily set in a connected state before the state change.

Description

Double-clutch type speed changer

Technical Field

The present invention relates to a dual clutch transmission.

Background

Patent document 1 discloses a dual clutch transmission in which a dual clutch device having two clutches is provided between an engine and a transmission, and power transmission from the engine to the transmission is switched between two systems.

Documents of the prior art

Patent document

Patent document 1: japanese patent application publication No. 2010-537144.

Disclosure of Invention

Problems to be solved by the invention

In the twin clutch transmission described in patent document 1, for example, during traveling in the even-numbered gear, pre-shifting is performed to the odd-numbered gear. When the pre-shift is performed, elements in a transmission path that do not contribute to power transmission from the engine to the wheels are driven by the engine to rotate, and thus oil agitation resistance increases, resulting in deterioration of fuel efficiency.

The purpose of the present invention is to provide a dual clutch transmission that can suppress deterioration in fuel efficiency due to stirring of oil.

Means for solving the problems

A twin clutch transmission according to one aspect of the present invention includes: a first input shaft having a first clutch capable of cutting off and engaging power from a drive source; a second input shaft having a second clutch capable of disconnecting and engaging power from the drive source and disposed coaxially with the first input shaft; a first sub-shaft disposed in parallel with the first input shaft; a second countershaft configured coaxially with the first countershaft and selectively coupled with the first countershaft; and an output shaft disposed coaxially with the first input shaft, for shifting from a first predetermined shift speed to a second predetermined shift speed, releasing the coupling between the first sub-shaft and the second sub-shaft to set a state in which power is not transmitted from the drive source to the first sub-shaft, the first predetermined shift speed is a shift speed in which power is transmitted from the drive source to the output shaft via the second input shaft, the first counter shaft, and the second counter shaft, the second predetermined shift speed is a shift speed in which power is transmitted from the drive source to the output shaft via the first input shaft and the second countershaft, when a state change is made in which power is transmitted from the drive source or the output shaft to the first sub-shaft, the second clutch is temporarily set to the connected state before the state change.

Effects of the invention

According to the shift control device of the present invention, it is possible to suppress deterioration of fuel efficiency due to agitation of oil.

Drawings

Fig. 1 is a schematic diagram (skeletton diagram) showing a dual clutch transmission of an embodiment.

Fig. 2 is a schematic diagram showing a state immediately after the shift from the 8 th gear to the 9 th gear.

Fig. 3 is a schematic diagram showing a running state in the 9-speed gear.

Fig. 4 is a flowchart showing the processing content of the oil agitation reduction control.

Fig. 5 is a schematic diagram showing a state immediately after a shift from the 4-speed gear to the 5-speed gear.

Fig. 6 is a schematic view showing a running state in 5 th gear.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the drawings. The embodiments described below are examples, and the present invention is not limited to these embodiments.

First, the overall structure of the twin clutch transmission 1 according to one embodiment will be described with reference to fig. 1. The left side in fig. 1 is the front side of the dual clutch transmission 1, and the right side in fig. 1 is the rear side of the dual clutch transmission 1.

The dual clutch transmission 1 includes a first clutch 10, a second clutch 20, and a transmission unit 30. On the output side of the transmission unit 30, drive wheels are coupled to enable power transmission via a propeller shaft, a differential, and a drive shaft, which are not shown.

The first clutch 10 is, for example, a hydraulically-operated wet multiple disc clutch having a plurality of input-side clutch plates 11 and a plurality of output-side clutch plates 12. The input side clutch plate 11 rotates integrally with the output shaft 2 of the engine (not shown). The output side clutch plate 12 rotates integrally with the first input shaft 31 of the transmission unit 30.

The first clutch 10 is biased in the disengagement direction by a return spring (not shown). The first clutch 10 is engaged by supplying a control hydraulic pressure to a hydraulic oil chamber of a piston (not shown) to move the piston, and connecting the input-side clutch plate 11 and the output-side clutch plate 12 under pressure. By engaging the first clutch 10, the power of the engine is transmitted to the first input shaft 31. The control device 40 controls the disengagement and engagement of the first clutch 10.

The second clutch 20 is disposed on the outer peripheral side of the first clutch 10. In the present embodiment, the case where the second clutch 20 is provided on the outer peripheral side of the first clutch 10 is described as an example, but the arrangement relationship between the first clutch 10 and the second clutch 20 is not limited to this. For example, the second clutch 20 may be disposed on the front side or the rear side of the first clutch 10.

The second clutch 20 is, for example, a hydraulically-operated wet multiple disc clutch having a plurality of input-side clutch plates 21 and a plurality of output-side clutch plates 22. The input side clutch plate 21 rotates integrally with the output shaft 2 of the engine. The output side clutch plate 22 rotates integrally with the second input shaft 32 of the transmission unit 30.

The second clutch 20 is biased in the disengagement direction by a return spring (not shown). The second clutch 20 is engaged by supplying a control hydraulic pressure to a hydraulic oil chamber of a piston (not shown) to move the piston, and connecting the input-side clutch plate 21 and the output-side clutch plate 22 under pressure. By engaging the second clutch 20, the power of the engine is transmitted to the second input shaft 32. The control device 40 controls the disengagement and engagement of the second clutch 20.

The transmission unit 30 includes a first input shaft 31 connected to the output side of the first clutch 10, and a second input shaft 32 connected to the output side of the second clutch 20. The transmission unit 30 includes a first counter shaft 33 and a second counter shaft 34 arranged in parallel with the first input shaft 31 and the second input shaft 32. The transmission unit 30 includes an output shaft 35 disposed coaxially with the first input shaft 31 and the second input shaft 32.

The first input shaft 31 is rotatably supported by the second input shaft 32 via a bearing (not shown). A second input gear 52a functioning as a reverse gear is fixed to an intermediate portion of the first input shaft 31 in the front-rear direction.

A first synchronizing hub 61a of a first synchronizing mechanism 61 (described later) is fixed to the first input shaft 31 at a stage subsequent to the second input gear 52 a.

A third input gear 53a is provided between the second input gear 52a and the first synchronous hub 61a so as to be relatively rotatable with respect to the first input shaft 31.

A fourth input gear 54a (corresponding to an "idler gear" of the present invention) is provided at a stage subsequent to the first synchronous hub 61a so as to be relatively rotatable with respect to the first input shaft 31.

The second input shaft 32 is a hollow shaft through which the first input shaft 31 is inserted, and is rotatably supported by a transmission case (not shown) through a bearing (not shown). A first input gear 51a is fixed to a rear end portion of the second input shaft 32. The first input gear 51a is disposed at a position further forward than the second input gear 52 a.

The first counter shaft 33 is rotatably supported by a transmission case (not shown) through a bearing (not shown). The first counter shaft 33 has a first counter gear 51b, a third synchronizing hub 63a of a third synchronizing mechanism 63 (described later), a sixth counter gear 56b, and a seventh counter gear 57b fixed thereto in this order from the front side.

The first counter gear 51b is in constant mesh with the first input gear 51 a. The first gear train 51 is constituted by the first input gear 51a and the first counter gear 51 b.

Between the first counter gear 51b and the third synchronizing mechanism 63, a second counter gear 52b is provided so as to be relatively rotatable with respect to the first counter shaft 33. The second sub-gear 52b is in constant mesh with the second input gear 52a via the reverse idle gear 52 c. The second input gear 52a, the reverse idle gear 52c, and the second counter gear 52b constitute a reverse gear train 52.

The second sub-shaft 34 is disposed between the third synchronizing mechanism 63 and the sixth sub-gear 56 b. The second sub-shaft 34 is a hollow shaft through which the first sub-shaft 33 is inserted, and is supported by the first sub-shaft 33 through a bearing (not shown) so as to be relatively rotatable. A third pinion gear 53b is fixed to a position in front of the second sub-shaft 34. The third counter gear 53b is in constant mesh with the third input gear 53 a. The third input gear 53a and the third pinion gear 53b constitute a second gear train 53.

A fourth counter gear 54b (corresponding to the "first counter gear" of the present invention) is fixed to the second counter shaft 34 at a position downstream of the third counter gear 53 b. The fourth counter gear 54b is in constant mesh with the fourth input gear 54 a. The fourth input gear 54a and the fourth pinion gear 54b constitute a third gear train 54. A fifth pinion 55b (corresponding to the "second pinion" of the present invention) is fixed to a rear end portion of the second counter shaft 34.

The output shaft 35 is rotatably supported by a transmission case (not shown) through a bearing (not shown). A second synchronizing hub 62a of a second synchronizing mechanism 62 (described later) is fixed to a distal end portion of the output shaft 35. A fourth synchronizing hub 64a of a fourth synchronizing mechanism 64 (described later) is fixed to the output shaft 35 at a position subsequent to the second synchronizing hub 62 a.

A first output gear 55a (corresponding to an "output gear" of the present invention) is provided between the second synchronizer hub 62a and the fourth synchronizer hub 64a so as to be relatively rotatable with respect to the output shaft 35. The first output gear 55a is in constant mesh with the fifth pinion gear 55 b. The fourth gear train 55 is constituted by the first output gear 55a and the fifth pinion gear 55 b.

A second output gear 56a is provided between the first output gear 55a and the fourth synchronizing hub 64a so as to be relatively rotatable with respect to the output shaft 35. The second output gear 56a is in constant mesh with the sixth pinion 56 b. The fifth gear train 56 is constituted by the second output gear 56a and the sixth pinion gear 56 b.

A third output gear 57a is provided at a stage subsequent to the fourth synchronizing hub 64a so as to be relatively rotatable with respect to the output shaft 35. The third output gear 57a is in constant mesh with the seventh pinion 57 b. The third output gear 57a and the seventh pinion 57b constitute a sixth gear train 57 (corresponding to a "fifth gear train" in the present invention).

The shifting portion 30 includes a first synchronizing mechanism 61, a second synchronizing mechanism 62, a third synchronizing mechanism 63, and a fourth synchronizing mechanism 64.

The first synchronizing mechanism 61 includes a first synchronizing hub 61a, a first synchronizing sleeve 61b, a first dog gear 61c, and a second dog gear 61 d. The first synchronizing hub 61a is fixed to the first input shaft 31 as described above.

The first synchronizing sleeve 61b is provided so as to surround the first synchronizing hub 61 a. The first synchronizing sleeve 61b has internal spline teeth that engage with the external spline teeth of the first synchronizing hub 61 a. The first synchronizing sleeve 61b rotates integrally with the first synchronizing hub 61a, and is movable in the front-rear direction with respect to the first synchronizing hub 61 a.

The first dog gear 61c is provided on the rear side of the third input gear 53 a. The second dog gear 61d is provided on the front side of the fourth input gear 54 a. Synchronizer rings (not shown) are provided between the first synchromesh hub 61a and the first dog gear 61c, and between the first synchromesh hub 61a and the second dog gear 61d, respectively. The spline internal teeth of the first synchronizing sleeve 61b can be selectively engaged with the spline external teeth of the first dog gear 61c or the spline external teeth of the second dog gear 61 d.

In the first synchronizing mechanism 61, the first synchronizing sleeve 61b is moved by a shift fork (not shown) to engage with the first dog gear 61c or the second dog gear 61d, thereby selectively synchronizing and coupling the first input shaft 31 with the third input gear 53a or the fourth input gear 54 a. The operation of the first synchronizing sleeve 61b is controlled by the control device 40.

The second synchronizing mechanism 62 includes a second synchronizing hub 62a, a second synchronizing sleeve 62b, a third cog gear 62c, and a fourth cog gear 62 d. The second synchronizer hub 62a is fixed to the output shaft 35 as described above.

The second synchronizing sleeve 62b is provided so as to surround the second synchronizing hub 62 a. The second synchronizing sleeve 62b has internal spline teeth that engage with the external spline teeth of the second synchronizing hub 62 a. The second synchronizing sleeve 62b rotates integrally with the second synchronizing hub 62a, and is movable in the front-rear direction with respect to the second synchronizing hub 62 a.

The third cog gear 62c is provided on the rear side of the fourth input gear 54 a. The fourth dog gear 62d is provided on the front side of the first output gear 55 a. Synchronizer rings (not shown) are provided between the second synchronizing hub 62a and the third dog gear 62c, and between the second synchronizing hub 62a and the fourth dog gear 62d, respectively. The spline internal teeth of the second synchronizing sleeve 62b can be selectively engaged with the spline external teeth of the third cog gear 62c or the spline external teeth of the fourth cog gear 62 d.

In the second synchronizing mechanism 62, the output shaft 35 is selectively synchronized with the fourth input gear 54a or the first output gear 55a by moving the second synchronizing sleeve 62b by a shift fork (not shown) to engage with the third dog gear 62c or the fourth dog gear 62 d. The operation of the second synchronizing sleeve 62b is controlled by the control device 40.

The third synchronizing mechanism 63 includes a third synchronizing hub 63a, a third synchronizing sleeve 63b, a fifth dog gear 63c, and a sixth dog gear 63 d. The third synchronizer hub 63a is fixed to the first countershaft 33 as described above.

The third synchronizing sleeve 63b is provided so as to surround the third synchronizing hub 63 a. The third synchronizing sleeve 63b has internal spline teeth that engage with the external spline teeth of the third synchronizing hub 63 a. The third synchronizing sleeve 63b rotates integrally with the third synchronizing hub 63a and is movable in the front-rear direction with respect to the third synchronizing hub 63 a.

The fifth dog gear 63c is provided on the rear side of the second sub-gear 52 b. The sixth dog gear 63d is provided at the front end portion of the second sub-shaft 34. Synchronizer rings (not shown) are provided between the third synchronizer hub 63a and the fifth dog gear 63c, and between the third synchronizer hub 63a and the sixth dog gear 63d, respectively. The spline internal teeth of the third synchronizing sleeve 63b can be selectively engaged with the spline external teeth of the fifth dog gear 63c or the spline external teeth of the sixth dog gear 63 d.

In the third synchronizing mechanism 63, the first counter shaft 33 is selectively synchronized with the second counter gear 52b or the second counter shaft 34 by moving the third synchronizing sleeve 63b by a shift fork (not shown) to engage with the fifth dog gear 63c or the sixth dog gear 63 d. The operation of the third synchronizing sleeve 63b is controlled by the control device 40.

The fourth synchronizing mechanism 64 includes a fourth synchronizing hub 64a, a fourth synchronizing sleeve 64b, a seventh dog gear 64c, and an eighth dog gear 64 d. The fourth synchronizer hub 64a is fixed to the output shaft 35 as described above.

The fourth synchronizing sleeve 64b is provided so as to surround the fourth synchronizing hub 64 a. The fourth synchronizing sleeve 64b has internal spline teeth that engage with the external spline teeth of the fourth synchronizing hub 64 a. The fourth synchronizing sleeve 64b rotates integrally with the fourth synchronizing hub 64a, and is movable in the front-rear direction with respect to the fourth synchronizing hub 64 a.

The seventh dog gear 64c is provided on the rear side of the second output gear 56 a. The eighth dog gear 64d is provided on the front side of the third output gear 57 a. Synchronizer rings (not shown) are provided between the fourth synchronizing hub 64a and the seventh dog gear 64c, and between the fourth synchronizing hub 64a and the eighth dog gear 64d, respectively. The spline internal teeth of the fourth synchronizing sleeve 64b can be selectively engaged with the spline external teeth of the seventh dog gear 64c or the spline external teeth of the eighth dog gear 64 d.

In the fourth synchronizing mechanism 64, the output shaft 35 is selectively synchronized with the second output gear 56a or the third output gear 57a by moving the fourth synchronizing sleeve 64b by a shift fork (not shown) to engage with the seventh dog gear 64c or the eighth dog gear 64 d. The operation of the fourth synchronizing sleeve 64b is controlled by the control device 40.

Next, the power transmission path of each shift stage of the twin clutch transmission 1 according to the present embodiment will be described. In the following, a case where the start is performed in the 1 st gear and the upshift is performed sequentially to the 9 th gear will be described as an example.

In the 1 st gear, the first clutch 10 is engaged, the first input shaft 31 is coupled to the fourth input gear 54a by the first synchronizing mechanism 61, the second counter shaft 34 is coupled to the first counter shaft 33 by the third synchronizing mechanism 63, and the second output gear 56a is coupled to the output shaft 35 by the fourth synchronizing mechanism 64.

That is, the power of the engine is transmitted through the first clutch 10 → the first input shaft 31 → the first synchronizing mechanism 61 → the third gear train 54 → the second sub-shaft 34 → the third synchronizing mechanism 63 → the first sub-shaft 33 → the fifth gear train 56 → the fourth synchronizing mechanism 64 → the output shaft 35, and the power transmission path of the 1 st gear is established.

In the 2-speed gear, the second clutch 20 is engaged, and the second output gear 56a is coupled with the output shaft 35 by the fourth synchronizing mechanism 64.

That is, the power of the engine is transmitted through the second clutch 20 → the second input shaft 32 → the first gear train 51 → the first counter shaft 33 → the fifth gear train 56 → the fourth synchronizing mechanism 64 → the output shaft 35, and the power transmission path of the 2-speed gear is established.

If the 2-speed gear is established, a pre-shift to the 3-speed gear is performed. Specifically, the third synchronization mechanism 63 releases the coupling between the second sub-shaft 34 and the first sub-shaft 33, and the second synchronization mechanism 62 couples the first output gear 55a to the output shaft 35.

In the 2-speed gear, the second clutch 20 is disengaged and the first clutch 10 is engaged in a state where the pre-shift to the 3-speed gear is completed, thereby realizing the 3-speed gear. In the 3-speed gear, the first clutch 10 is engaged, the first input shaft 31 is coupled to the fourth input gear 54a by the first synchronizing mechanism 61, and the first output gear 55a is coupled to the output shaft 35 by the second synchronizing mechanism 62.

That is, the power of the engine is transmitted through the first clutch 10 → the first input shaft 31 → the first synchronizing mechanism 61 → the third gear train 54 → the second counter shaft 34 → the fourth gear train 55 → the second synchronizing mechanism 62 → the output shaft 35, and the power transmission path of the 3-speed gear is established.

If 3-speed is established, a pre-shift to 4-speed is performed. Specifically, the coupling of the second output gear 56a and the output shaft 35 by the fourth synchronization mechanism 64 is released, and the first counter shaft 33 and the second counter shaft 34 are coupled by the third synchronization mechanism 63.

In the 3-speed gear, the first clutch 10 is disengaged and the second clutch 20 is engaged in a state where the pre-shift to the 4-speed gear is completed, thereby realizing the 4-speed gear. In the 4-speed gear, the second clutch 20 is engaged, the first output gear 55a is coupled to the output shaft 35 by the second synchronization mechanism 62, and the first counter shaft 33 is coupled to the second counter shaft 34 by the third synchronization mechanism 63.

That is, the power of the engine is transmitted through the second clutch 20 → the second input shaft 32 → the first gear train 51 → the first counter shaft 33 → the third synchronizing mechanism 63 → the second counter shaft 34 → the fourth gear train 55 → the second synchronizing mechanism 62 → the output shaft 35, and the power transmission path of the 4 th gear is established.

If the 4-speed gear is established, a pre-shift to the 5-speed gear is performed. Specifically, the first input shaft 31 is decoupled from the fourth input gear 54a and the first input shaft 31 is coupled to the third input gear 53a by the first synchronization mechanism 61.

In the 4-speed gear, the second clutch 20 is disengaged and the first clutch 10 is engaged in a state where the pre-shift to the 5-speed gear is completed, thereby realizing the 5-speed gear. In the 5-speed gear, the first clutch 10 is engaged, the first input shaft 31 is coupled to the third input gear 53a by the first synchronizing mechanism 61, and the first output gear 55a is coupled to the output shaft 35 by the second synchronizing mechanism 62.

That is, the power of the engine is transmitted through the first clutch 10 → the first input shaft 31 → the first synchronizing mechanism 61 → the second gear train 53 → the second counter shaft 34 → the fourth gear train 55 → the second synchronizing mechanism 62 → the output shaft 35, and the power transmission path of the 5 th gear is established.

If the 5-speed gear is established, a pre-shift to the 6-speed gear is performed. Specifically, the third synchronizing mechanism 63 releases the coupling between the second sub-shaft 34 and the first sub-shaft 33, and the fourth synchronizing mechanism 64 couples the third output gear 57a to the output shaft 35.

In the 5-speed gear, the first clutch 10 is disengaged and the second clutch 20 is engaged in a state where the pre-shift to the 6-speed gear is completed, thereby realizing the 6-speed gear. In the 6 th gear, the second clutch 20 is engaged, and the third output gear 57a is coupled to the output shaft 35 by the fourth synchronizing mechanism 64.

That is, the power of the engine is transmitted through the second clutch 20 → the second input shaft 32 → the first gear train 51 → the first counter shaft 33 → the sixth gear train 57 → the fourth synchronizing mechanism 64 → the output shaft 35, and the power transmission path of the 6 th gear is established.

If the 6 th gear is established, a pre-shift to the 7 th gear is performed. Specifically, the first input shaft 31 is decoupled from the third input gear 53a and the first input shaft 31 is coupled to the fourth input gear 54a by the first synchronizing mechanism 61, and the first output gear 55a is decoupled from the output shaft 35 and the fourth input gear 54a is coupled to the output shaft 35 by the second synchronizing mechanism 62.

In the 6 th gear, the second clutch 20 is disengaged and the first clutch 10 is engaged in a state where the pre-shift to the 7 th gear is completed, thereby realizing the 7 th gear. In the 7 th gear, the first clutch 10 is engaged, the first synchronization mechanism 61 couples the first input shaft 31 to the fourth input gear 54a, and the second synchronization mechanism 62 couples the fourth input gear 54a to the output shaft 35.

That is, the power of the engine is transmitted through the first clutch 10 → the first input shaft 31 → the first synchronizing mechanism 61 → the fourth input gear 54a → the second synchronizing mechanism 62 → the output shaft 35, and the power transmission path of the 7 th gear is established. The 7 th gear is a direct gear.

If 7 th gear is established, a pre-shift to 8 th gear is performed. Specifically, the third output gear 57a and the output shaft 35 are disengaged from each other by the fourth synchronization mechanism 64, and the first counter shaft 33 and the second counter shaft 34 are coupled to each other by the third synchronization mechanism 63.

In the 7-speed gear, the first clutch 10 is disengaged and the second clutch 20 is engaged in a state where the pre-shift to the 8-speed gear is completed, thereby realizing the 8-speed gear. In the 8-speed gear, the second clutch 20 is engaged, the fourth input gear 54a is coupled to the output shaft 35 by the second synchronization mechanism 62, and the first counter shaft 33 is coupled to the second counter shaft 34 by the third synchronization mechanism 63.

That is, the power of the engine is transmitted through the second clutch 20 → the second input shaft 32 → the first gear train 51 → the first counter shaft 33 → the third synchronizing mechanism 63 → the second counter shaft 34 → the third gear train 54 → the second synchronizing mechanism 62 → the output shaft 35, and the power transmission path of the 8 th gear is established.

If the 8-speed gear is established, a pre-shift to the 9-speed gear is performed. Specifically, the first input shaft 31 is decoupled from the fourth input gear 54a and the first input shaft 31 is coupled to the third input gear 53a by the first synchronization mechanism 61.

In the 8-speed gear, the second clutch 20 is disengaged and the first clutch 10 is engaged in a state where the pre-shift to the 9-speed gear is completed, thereby realizing the 9-speed gear. In the 9-speed gear, the first clutch 10 is engaged, the first input shaft 31 is coupled to the third input gear 53a by the first synchronizing mechanism 61, and the fourth input gear 54a is coupled to the output shaft 35 by the second synchronizing mechanism 62.

That is, the power of the engine is transmitted through the first clutch 10 → the first input shaft 31 → the first synchronizing mechanism 61 → the second gear train 53 → the second sub-shaft 34 → the third gear train 54 → the second synchronizing mechanism 62 → the output shaft 35, and the power transmission path of the 9 th gear is established.

Next, an outline of the oil agitation reduction control performed at the 9 th gear in the dual clutch transmission 1 of the present embodiment will be specifically described with reference to fig. 2 and 3. Fig. 2 shows the case immediately after the upshift from the 8 th gear to the 9 th gear.

In fig. 2 and 3, a thick line indicates a power transmission path that contributes to power transmission from the engine to the output shaft 35. The solid line indicates a member to which the rotational power from the engine is transmitted although it does not contribute to the transmission of power from the engine to the output shaft 35. In addition, the broken line indicates a member to which the rotational power from the engine is not transmitted.

As shown in fig. 2, immediately after the upshift from the 8 th gear to the 9 th gear, the third synchronization mechanism 63 is in a state in which the first sub-shaft 33 and the second sub-shaft 34 are coupled.

Therefore, the rotational power from the engine is also transmitted to the first counter shaft 33 via the first input shaft 31, the third input gear 53a, and the second counter shaft 34. Thereby, the first counter gear 51b, the sixth counter gear 56b, and the seventh counter gear 57b fixed to the first counter shaft 33 are driven to rotate by the engine. Therefore, the rotation of the first, sixth, and

seventh pinions

51b, 56b, and 57b increases the stirring resistance of the lubricating oil in the transmission case, resulting in deterioration of fuel efficiency.

In the present embodiment, the following operation is performed to prevent the first counter shaft 33 from being driven and rotated by the engine after the shift from the 8 th gear to the 9 th gear.

Specifically, after the upshift from the 8 th gear to the 9 th gear, the third synchronization mechanism 63 releases the engagement between the first sub-shaft 33 and the second sub-shaft 34 in the 9 th gear state (see fig. 3). This prevents the rotational power from the engine from being transmitted to the first counter shaft 33. Therefore, deterioration in fuel efficiency due to stirring of the lubricating oil can be suppressed.

However, when the first sub-shaft 33 and the second sub-shaft 34 are again coupled by the third synchronization mechanism 63, such as when the shift to the 8 th gear is performed due to a decrease in the vehicle speed during the 9 th gear running, the following problem may occur.

That is, the second sub-shaft 34 rotates at a high speed, whereas the first sub-shaft 33 rotates at a low speed. Therefore, if the first sub-shaft 33 and the second sub-shaft 34 are directly coupled by the third synchronization mechanism 63, an excessive load may be applied to the third synchronization mechanism 63.

Therefore, in the present embodiment, in order to prevent an excessive load from being applied to the third synchronization mechanism 63, the following operations are performed before the first sub-shaft 33 and the second sub-shaft 34 are re-coupled by the third synchronization mechanism 63.

Specifically, the second clutch 20 is engaged once before the third synchronizing sleeve 63b is engaged with the sixth dog gear 63 d.

As a result, the power of the engine is transmitted to the first counter shaft 33 via the second input shaft 32, and the rotation speed of the first counter shaft 33 increases. When the rotation speed of the first counter shaft 33 increases to a sufficient level, the engaged second clutch 20 is disengaged, and the third synchronizing sleeve 63b and the sixth dog gear 63d are engaged. Thereby, the load applied to the third synchronization mechanism 63 can be reduced.

Next, the processing contents of the oil agitation reduction control will be described with reference to the flowchart of fig. 4. When the shift from the 8-speed gear to the 9-speed gear is performed, the oil agitation reduction control described above is started.

First, in step S1, control device 40 determines whether or not pre-shifting is not required. This determination is made based on, for example, the vehicle speed. Further, this determination may be made by, for example, determining whether there is a possibility of shifting into the 8 th gear.

When it is determined in step S1 that pre-shifting is not necessary (step S1: no), the process of step S1 is repeated. On the other hand, in a case where it is determined in step S1 that pre-shifting is not required (step S1: YES), the processing proceeds to step S2.

In step S2, the control device 40 causes an upshift in the third synchronization mechanism 63. Specifically, the engagement state of the third synchronizing sleeve 63b and the sixth dog gear 63d is released.

In step S3, which follows step S2, the control device 40 determines whether a pre-shift is required. This determination is made based on the vehicle speed and the like, for example, as in step S1 described above.

When it is determined in step S3 that pre-shifting is not required (step S3: NO), the process of step S3 is repeated. On the other hand, in the case where it is determined in step S3 that pre-shifting is required (step S3: YES), the processing proceeds to step S4.

In step S4, the control device 40 determines whether or not the difference in the rotational speed between the first sub-shaft 33 and the second sub-shaft 34 is equal to or less than a predetermined threshold value. This determination is made, for example, by detecting the rotation speed of the first sub-shaft 33 and the rotation speed of the second sub-shaft 34 by a rotation speed sensor, not shown, and directly obtaining a rotation speed difference. In this case, the threshold value may be stored in the control device 40 as a rotational speed difference obtained through experiments or the like without applying an excessive load to the third synchronizing mechanism 63.

The determination in step S4 may be performed by measuring the time elapsed after the gear-out in the third synchronization mechanism 63. In this case, the time required from the gear disengagement to the time when the above-described difference in rotational speed exceeds the predetermined threshold value may be obtained through experiments.

If it is determined in step S4 that the difference in the rotational speeds of the first sub-shaft 33 and the second sub-shaft 34 is equal to or less than the predetermined threshold value (step S4: "yes"), the process proceeds to step S8 (described later). On the other hand, when it is determined in step S4 that the difference in the rotational speed between the first sub-shaft 33 and the second sub-shaft 34 is not equal to or less than the predetermined threshold value (step S4: no), the process proceeds to step S5.

In step S5, the control device 40 engages the second clutch 20. Specifically, the second clutch 20 is completely engaged. Further, the second clutch 20 may be slip-engaged. When the second clutch 20 is engaged in step S5, the process proceeds to step S6.

In step S6, the control device 40 determines whether or not the difference in the rotational speed between the first sub-shaft 33 and the second sub-shaft 34 is equal to or less than a threshold value. This determination is made, for example, by detecting the rotation speed of the first sub-shaft 33 and the rotation speed of the second sub-shaft 34 by a rotation speed sensor, not shown, and directly obtaining a rotation speed difference. When the second clutch 20 is completely engaged, an engagement time required to bring the second clutch 20 from the disengaged state to the completely engaged state may be determined in advance by experiments, and a simple determination may be made based on whether or not the engagement time has elapsed.

If it is determined in step S6 that the difference in the rotational speed between the first sub-shaft 33 and the second sub-shaft 34 is not equal to or less than the predetermined threshold value (step S6: no), the process of step S6 is repeated. On the other hand, when it is determined in step S6 that the difference in the rotational speed between the first sub-shaft 33 and the second sub-shaft 34 is equal to or less than the predetermined threshold value (step S6: "yes"), the process proceeds to step S7.

In step S7, the control device 40 releases the engagement of the second clutch 20. Then, the process advances to step S8.

In step S8, the control device 40 causes the third synchronization mechanism 63 to engage in gear. Specifically, the third synchronizing sleeve 63b is engaged with the sixth dog gear 63 d.

As described above, according to the present embodiment, when the shift from the 8 th gear to the 9 th gear is performed, the third synchronization mechanism 63 releases the engagement between the first sub-shaft 33 and the second sub-shaft 34. This prevents the rotational power from the engine from being transmitted to the first counter shaft 33. Therefore, deterioration in fuel efficiency due to stirring of the lubricating oil can be suppressed.

Further, according to the present embodiment, when the first sub-shaft 33 and the second sub-shaft 34 are coupled again by the third synchronizing mechanism 63, the second clutch 20 is temporarily engaged. Therefore, the load applied to the third synchronization mechanism 63 can be reduced.

Further, according to the present embodiment, when the difference in the rotational speed between the first sub-shaft 33 and the second sub-shaft 34 exceeds a predetermined threshold value, the second clutch 20 is temporarily engaged. In other words, when the relative rotation speed between the first counter shaft 33 and the second counter shaft 34 is small and equal to or less than a predetermined threshold value, the third synchronization mechanism 63 is engaged without temporarily engaging the second clutch 20. Therefore, in the case where the load applied to the third synchronizing mechanism 63 is not so large, the time required for the pre-shift can be shortened.

(modification example)

In the above-described embodiment, the case where the gear shift from the 8 th gear to the 9 th gear is performed is described as an example, but the present invention is not limited to this. For example, even when the gear shift from the 4 th gear to the 5 th gear is performed, the same effect can be obtained by the same control. Next, the case where the gear shift from the 4 th gear to the 5 th gear is performed will be described in detail.

Fig. 5 shows the case immediately after the upshift from the 4 th gear to the 5 th gear. As shown in fig. 5, immediately after the upshift from the 4 th gear to the 5 th gear, the third synchronization mechanism 63 is in a state in which the first sub-shaft 33 and the second sub-shaft 34 are coupled.

seventh pinions

In this example, the following operation is performed to prevent the first counter shaft 33 from being driven and rotated by the engine after the shift from the 4 th gear to the 5 th gear.

Specifically, after the upshift from the 4 th gear to the 5 th gear, the third synchronization mechanism 63 releases the engagement between the first sub-shaft 33 and the second sub-shaft 34 in the 5 th gear state (see fig. 6). This prevents the rotational power from the engine from being transmitted to the first counter shaft 33. Therefore, deterioration in fuel efficiency due to stirring of the lubricating oil can be suppressed.

However, when the shift to the 4 th gear is performed due to a decrease in the vehicle speed or the like during the 5 th gear running, the first sub-shaft 33 and the second sub-shaft 34 are again coupled by the third synchronization mechanism 63. In this case, the following problems may occur.

Therefore, in this example, in order to prevent an excessive load from being applied to the third synchronization mechanism 63, the following operations are performed before the first sub-shaft 33 and the second sub-shaft 34 are re-coupled by the third synchronization mechanism 63.

Further, when the speed is changed to the 6 th gear due to an increase in the vehicle speed or the like while the 5 th gear is traveling in a state in which the engagement between the first sub-shaft 33 and the second sub-shaft 34 is released, the third output gear 57a is coupled to the output shaft 35 by the fourth synchronizing mechanism 64. In this case, the following problems may occur.

That is, the output shaft 35 rotates at a high speed, whereas the third output gear 57a rotates at a low speed. Therefore, if the third output gear 57a is directly coupled to the output shaft 35 by the fourth synchronizing mechanism 64, an excessive load may be applied to the fourth synchronizing mechanism 64.

Therefore, in this example, in order to prevent an excessive load from being applied to the fourth synchronizing mechanism 64, the following operation is performed before the third output gear 57a and the output shaft 35 are coupled by the fourth synchronizing mechanism 64.

Specifically, the second clutch 20 is engaged once before the fourth synchronizing sleeve 64b is engaged with the eighth dog gear 64 d.

Accordingly, the power of the engine is transmitted to the third output gear 57a via the second input shaft 32, the first gear train 51, the first counter shaft 33, and the seventh counter gear 57b, and the rotation speed of the third output gear 57a is increased. When the rotation speed of the third output gear 57a increases to a sufficient degree, the engaged second clutch 20 is disengaged, and the fourth synchronizing sleeve 64b and the eighth dog gear 64d are engaged. This can reduce the load applied to the fourth synchronizing mechanism 64.

(Another example of load reduction control of the synchronization mechanism)

However, for example, when the pre-shift to the 4-speed is performed immediately after the downshift from the 6-speed to the 5-speed, the third output gear 57a and the output shaft 35 are disengaged from each other by the fourth synchronization mechanism 64, and then the first counter shaft 33 and the second counter shaft 34 are coupled to each other by the third synchronization mechanism 63. In this case, the following problems may occur.

That is, the fourth synchronization mechanism 64 releases the coupling of the third output gear 57a and the output shaft 35, whereby the first counter shaft 33 is separated from the engine, and the rotational power from the engine is not transmitted to the first counter shaft 33. Therefore, the rotation speed of the first counter shaft 33, which is lower than the rotation speed of the second counter shaft 34, is further reduced by the stirring resistance of the lubricating oil in the transmission case. In this state, if the first sub-shaft 33 and the second sub-shaft 34 are directly coupled by the third synchronization mechanism 63, an excessive load may be applied to the third synchronization mechanism 63.

Therefore, in this example, in order to prevent an excessive load from being applied to the third synchronizing mechanism 63, the following operations are performed after the third output gear 57a is disengaged from the output shaft 35 by the fourth synchronizing mechanism 64 and before the first sub-shaft 33 is coupled to the second sub-shaft 34 by the third synchronizing mechanism 63.

Specifically, after the engagement between the fourth synchronizing sleeve 64b and the eighth dog gear 64d is released, the second clutch 20 is once engaged before the third synchronizing sleeve 63b and the sixth dog gear 63d are engaged.

As a result, the power of the engine is transmitted to the first counter shaft 33 via the second input shaft 32, and the rotation speed of the first counter shaft 33 increases. When the rotation speed of the first counter shaft 33 increases to a sufficient level, the engaged second clutch 20 is disengaged, and the third synchronizing sleeve 63b and the sixth dog gear 63d are engaged.

Thereby, the load applied to the third synchronization mechanism 63 can be reduced. The load reduction control of the synchronization mechanism is not limited to the case of pre-shifting to the 4-speed gear immediately after the downshift from the 6-speed gear to the 5-speed gear.

The present application is based on the japanese patent application filed on 12/10/2017 (japanese patent application 2017-198763), the contents of which are incorporated herein by reference.

Industrial applicability

The twin clutch transmission of the present invention can suppress deterioration of fuel consumption due to stirring of oil, and has high industrial applicability.

Description of the reference numerals

1 Dual-clutch transmission

2 output shaft

10 first clutch

11 input side clutch plate

12 output side clutch plate

20 second clutch

21 input side clutch plate

22 output side clutch plate

30 speed changing part

31 first input shaft

32 second input shaft

33 first countershaft

34 second countershaft

35 output shaft

40 control device

51 first gear train

51a first input gear

51b first pinion

52 rear-wheel gear train

52a second input gear

52b second sub-gear

52c reverse idler gear

53 second gear train

53a third input gear

53b third pinion

54 third Gear train

54a fourth input gear

54b fourth pinion

55 fourth gear train

55a first output gear

55b fifth pinion

56 fifth Gear train

56a second output gear

56b sixth pinion

57 sixth Gear train

57a third output gear

57b seventh pinion

61 first synchronization mechanism

61a first synchronous hub

61b first synchronizing sleeve

61c first jaw gear

61d second jaw gear

62 second synchronizing mechanism

62a second synchronizer hub

62b second synchronizing sleeve

62c third cog wheel

62d fourth dog gear

63 third synchronizing mechanism

63a third synchromesh hub

63b third synchronizing sleeve

63c fifth jaw gear

63d sixth dog gear

64 fourth synchronizing mechanism

64a fourth synchronizer hub

64b fourth synchronizing sleeve

64c seventh dog gear

64d eighth dog gear

Claims

1. A twin-clutch transmission is provided with: a first input shaft having a first clutch capable of cutting off and engaging power from a drive source; a second input shaft having a second clutch capable of disconnecting and engaging power from the drive source and disposed coaxially with the first input shaft; a first sub-shaft disposed in parallel with the first input shaft; a second countershaft configured coaxially with the first countershaft and selectively coupled with the first countershaft; and an output shaft disposed coaxially with the first input shaft,

when a shift is performed from a first predetermined shift speed to a second predetermined shift speed, the first predetermined shift speed being a shift speed at which power is transmitted from the drive source to the output shaft via the second input shaft, the first countershaft, and the second countershaft, the second predetermined shift speed being a shift speed at which power is transmitted from the drive source to the output shaft via the first input shaft and the second countershaft,

and, when a predetermined state change is performed, the second clutch is temporarily set to the engaged state while maintaining the engaged state of the first clutch until the predetermined state change,

the predetermined state change is a change from a state in which power is transmitted from the drive source to the first sub-shaft via the first input shaft and the second sub-shaft to the output shaft without transmitting power from the drive source to the first sub-shaft.

2. A dual clutch transmission as described in claim 1,

the second clutch is temporarily engaged when the relative rotation speed between the first countershaft and the second countershaft exceeds a predetermined threshold value after the first countershaft and the second countershaft are disengaged.

3. The twin-clutch transmission according to claim 1, comprising:

a first gear train that performs power transmission between the second input shaft and the first sub-shaft;

a second gear train that selectively performs power transmission between the first input shaft and the second sub-shaft;

a third gear train having an idler gear coupleable with the first input shaft and the output shaft and a first counter gear fixedly provided to the second counter shaft;

a fourth gear train having a second counter gear fixedly provided on the second counter shaft and an output gear capable of being coupled with the output shaft; and

a fifth gear train selectively performing power transmission between the first countershaft and the output shaft.

4. A dual clutch transmission as described in claim 3,

in the first predetermined gear stage, power is transmitted from the drive source to the output shaft via the first gear train and the third gear train,

in the second predetermined shift speed, power is transmitted from the drive source to the output shaft via the second gear train and the third gear train.

5. A dual clutch transmission as described in claim 3,

in the first predetermined gear stage, power is transmitted from the drive source to the output shaft via the first gear train and the fourth gear train,

in the second predetermined shift speed, power is transmitted from the drive source to the output shaft via the second gear train and the fourth gear train.