CN112297819A - Four-wheel drive system and vehicle - Google Patents
Four-wheel drive system and vehicle Download PDFInfo
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- CN112297819A CN112297819A CN201910699973.1A CN201910699973A CN112297819A CN 112297819 A CN112297819 A CN 112297819A CN 201910699973 A CN201910699973 A CN 201910699973A CN 112297819 A CN112297819 A CN 112297819A
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- wheel drive
- drive system
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00
- B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
- B60K6/22—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs
- B60K6/36—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs characterised by the transmission gearings
- B60K6/365—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines ; Control systems therefor, i.e. systems controlling two or more prime movers, or controlling one of these prime movers and any of the transmission, drive or drive units Informative references: mechanical gearings with secondary electric drive F16H3/72; arrangements for handling mechanical energy structurally associated with the dynamo-electric machine H02K7/00; machines comprising structurally interrelated motor and generator parts H02K51/00; dynamo-electric machines not otherwise provided for in H02K see H02K99/00 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by apparatus, components or means specially adapted for HEVs characterised by the transmission gearings with the gears having orbital motion
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K17/00—Arrangement or mounting of transmissions in vehicles
- B60K17/34—Arrangement or mounting of transmissions in vehicles for driving both front and rear wheels, e.g. four wheel drive vehicles
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/62—Hybrid vehicles
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Arrangement And Driving Of Transmission Devices (AREA)
Abstract
The invention provides a four-wheel drive system and a vehicle. The four-wheel drive system includes two planetary gear mechanisms having planetary carriers fixed to each other, an engine drivingly coupled to a first sun gear, and a first motor drivingly coupled to a second sun gear. Further, the first ring gear is locked and fixed or is in transmission coupling with an additional power source, the second planet carrier and the second ring gear can be locked and fixed through the engagement of the first brake, the first planet carrier is used for transmitting torque to one driving shaft of the vehicle, and the second ring gear is used for transmitting torque to the second driving shaft. In this way, the four-wheel drive system according to the present invention is able to switch between the timely four-wheel drive mode and the time-shared four-wheel drive mode by engagement/disengagement of the first brake, so that there is no inherent problem as with the conventional four-wheel drive system having only a single four-wheel drive mode.
Description
Technical Field
The present invention relates to the field of vehicles, and more particularly to a four-wheel drive system and a vehicle including the same.
Background
Currently, four-wheel drive systems commonly used in vehicles include time-sharing four-wheel drive systems and timely four-wheel drive systems. Both the time-share four-wheel drive system and the real-time four-wheel drive system can be switched between a two-wheel drive state and a four-wheel drive state, and generally the four-wheel drive state is only switched under appropriate conditions, such as when the vehicle needs to go off-road.
The time-sharing four-wheel drive system needs to manually switch the two-wheel drive state and the four-wheel drive state. In the four-wheel drive state, the output torque is transmitted to both drive shafts of the vehicle at substantially the same magnitude. However, the conventional time-sharing four-wheel drive system has a curve braking phenomenon in a four-wheel drive state, so that the steering of the vehicle is a problem.
Common implementations of transitions in drive states in a timely four-wheel drive system include various mechanical structures such as fluid coupling mechanisms, multi-plate clutches, and the like. However, although the existing timely four-wheel drive system can realize the switching between the two-wheel drive state and the four-wheel drive state through the various mechanical mechanisms, the existing timely four-wheel drive system has the problems of slow response, low system reliability, insufficient precision, limited off-road capability and the like.
Disclosure of Invention
The present invention has been made in view of the above-mentioned problems of the prior art. It is an object of the present invention to provide a new four wheel drive system which avoids the problems inherent in the time-sharing four-wheel drive system and the timely four-wheel drive system described above. In addition, another object of the present invention is to provide a vehicle including the four-wheel drive system described above.
In order to achieve the above object, the present invention adopts the following technical solutions.
The present invention provides a four-wheel drive system comprising:
a transmission including a first planetary gear mechanism and a second planetary gear mechanism that are coaxially arranged, the first planetary gear mechanism including a first sun gear, a plurality of first planetary gears, a first carrier, and a first ring gear, the second planetary gear mechanism including a second sun gear, a plurality of second planetary gears, a second carrier, and a second ring gear, the first carrier and the second carrier being fixed to each other;
an engine, wherein an output shaft of the engine is in transmission coupling with a first sun gear shaft of the first sun gear or is directly connected with the first sun gear shaft in a coaxial mode;
a first motor, wherein an input/output shaft of the first motor is in transmission coupling with a second sun gear shaft of the second sun gear or is directly connected with the second sun gear shaft in a coaxial manner; and
a first brake that is provided between the second carrier and the second ring gear and that is capable of locking the second carrier and the second ring gear to each other after engagement of the first brake,
wherein the first ring gear is locked fixed or drivingly coupled to an additional power source other than the engine and the first electric machine, the first carrier is configured to transmit torque to a first drive shaft of a vehicle, and the second ring gear is configured to transmit torque to a second drive shaft of the vehicle.
Preferably, the additional power source is a second motor.
More preferably, the four-wheel drive system further comprises: a second brake capable of locking the first sun gear fixed after engagement; and a third brake capable of locking and fixing the first ring gear after the third brake is engaged.
More preferably, the first brake, the second brake and/or the third brake are clutches.
More preferably, the four-wheel drive system further comprises a control module capable of controlling the four-wheel drive system to realize a time-sharing four-wheel drive mode and a timely four-wheel drive mode, the first brake is engaged to lock and fix the second carrier and the second ring gear to each other to realize the time-sharing four-wheel drive mode, and the first brake is disengaged to unlock and fix the second carrier and the second ring gear to realize the timely four-wheel drive mode.
More preferably, when the four-wheel drive system realizes the timely four-wheel drive mode, the four-wheel drive system is capable of realizing a two-wheel drive state when the first motor does not output torque, and the four-wheel drive system realizes a four-wheel drive state when the first motor outputs negative torque.
More preferably, when the four-wheel drive system is implementing the four-wheel-drive-in-time mode,
satisfy Tout1＝TICE+TMG2+(1+i2)TMG1And Tout2＝-i2TMG1
Wherein i2For the gear ratio from the second sun gear to the second ring gear when the second planet carrier is locked stationary, TICEIs the torque of the first sun gear, TMG1Is the torque of the second sun gear, TMG2Is the torque of the first ring gear, Tout1Is the output torque of the first planet carrier, Tout2Is the output torque of the second ring gear.
More preferably, when the four-wheel drive system achieves the four-wheel-drive-in-time mode, the four-wheel drive system is capable of achieving a power-split drive mode in which both the second brake and the third brake are off.
More preferably, when the four-wheel drive system realizes the time-sharing four-wheel drive mode, the second planet wheel carrier is rigidly connected with the second gear ring, and the four-wheel drive system always realizes a four-wheel drive state.
The invention also provides a vehicle comprising the four-wheel drive system according to any one of the above claims.
By adopting the technical scheme, the invention provides a novel four-wheel drive system and a vehicle comprising the same. The four-wheel drive system includes two planetary gear mechanisms having planetary carriers fixed to each other, an engine drivingly coupled to a first sun gear, and a first motor drivingly coupled to a second sun gear. Further, the first ring gear is locked and fixed or is in transmission coupling with an additional power source, the second planet carrier and the second ring gear can be locked and fixed through the engagement of the first brake, the first planet carrier is used for transmitting torque to one driving shaft of the vehicle, and the second ring gear is used for transmitting torque to the second driving shaft.
In this way, the four-wheel drive system according to the present invention is able to switch between the timely four-wheel drive mode and the time-shared four-wheel drive mode by engagement/disengagement of the first brake, so that there is no inherent problem as with the conventional four-wheel drive system having only a single four-wheel drive mode.
Drawings
FIG. 1a is a block diagram showing the topology of a four wheel drive system according to a first embodiment of the present invention; FIG. 1b is a lever diagram illustrating moment analysis of the four-wheel drive system of FIG. 1a in a timely four-wheel drive mode; FIG. 1c is a lever diagram illustrating moment analysis of the four-wheel drive system of FIG. 1a in a time-share four-wheel drive mode.
FIG. 2a is a block diagram showing the topology of a four wheel drive system according to a second embodiment of the present invention; FIG. 2b is a lever diagram illustrating moment analysis of the four-wheel drive system of FIG. 2a in a timely four-wheel drive mode; fig. 2c is a lever diagram illustrating the moment analysis of the four-wheel drive system of fig. 2a in a time-share four-wheel drive mode.
Description of the reference numerals
ICE engine MG1 first electric machine MG2 second electric machine S1 first sun wheel P1 first carrier PG1 first planet wheel R1 first ring gear S2 second sun wheel P2 second planet wheel R2 second ring gear B2 second ring gear B1 first brake B2 second brake B3 third brake G1 first output gear G2 second output gear G3 carrier output gear G4 input/output gear FD1 first driveshaft FD2 second driveshaft GB gearbox.
Detailed Description
Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the detailed description is intended only to teach one skilled in the art how to practice the invention, and is not intended to be exhaustive or to limit the scope of the invention. In the present invention, "drive coupling" means that a driving force/torque can be transmitted between two members, and means that the driving force/torque is transmitted between the two members by using a direct connection or via a known torque transmission mechanism such as a conventional gear pair, etc., unless otherwise specified.
(Structure of four-wheel drive System according to first embodiment of the invention)
As shown in fig. 1a, the four-wheel drive system according to the first embodiment of the invention includes one engine ICE, two electric machines (i.e., a first electric machine MG1 and a second electric machine MG2), and a transmission.
Specifically, in the present embodiment, the transmission includes two planetary gear mechanisms arranged side by side in a coaxial manner, and three brakes (i.e., a first brake B1, a second brake B2, and a third brake B3).
The first planetary gear mechanism includes a first sun gear S1, a plurality of first planetary gears PG1, a first ring gear R1, and a first carrier P1 for holding the plurality of first planetary gears PG1, which are meshed with each other. The first sun gear shaft of the first sun gear S1 extends toward the right in fig. 1a and is directly connected to the output shaft of the engine ICE in a coaxial manner with the output shaft of the engine ICE. The above "directly connected in a coaxial manner" means that the first sun gear shaft and the output shaft of the engine ICE may be the same shaft or that the first sun gear shaft and the output shaft of the engine ICE are both rigidly connected in a coaxial manner, and the same expressions have the same meaning in this application. The first carrier P1 has a carrier output gear G3 fixed thereto, and the carrier output gear G3 is always in engagement with the first output gear G1, so that torque from the first carrier P1 can be transmitted to the first drive shaft FD 1. The first ring gear R1 is constantly in mesh with an input/output gear G4 fixed to an input/output shaft of the second motor MG 2.
The second planetary gear mechanism includes a second sun gear S2, a plurality of second planetary gears PG2, a second ring gear R2, and a second carrier P2 for holding the plurality of second planetary gears PG2, which are engaged with each other. A second sun gear shaft of the second sun gear S2 extends toward the left in fig. 1a and is directly connected to an input/output shaft of the first motor MG1 coaxially with the input/output shaft of the first motor MG 1. The second carrier P2 and the first carrier P1 are fixed to each other. That is, in the present embodiment, the second planetary gear mechanism shares one carrier with the first planetary gear mechanism. In addition, in order to achieve fixation between the second carrier P2 and the first carrier P1 having different radial dimensions, a fixed connection portion may be provided between the second carrier P2 and the first carrier P1 as necessary. The second ring gear R2 is always in mesh with the second output gear G2, so that torque from the second ring gear R2 can be transmitted to the second drive shaft FD 2.
In addition, a first brake B1 is provided between the second ring gear R2 and the second carrier P2 such that the second ring gear R2 is lock-fixed with the second carrier P2 when the first brake B1 is engaged. Further, the first sun gear S1 is locked and fixed when the second brake B2 is engaged, and the first ring gear R1 is locked and fixed when the third brake B3 is engaged.
Further, in the present embodiment, the engine ICE is, for example, a four-cylinder engine and is provided on one side of the transmission (the right side in fig. 1 a). On the one hand, as described above, the output shaft of the engine ICE is directly connected to the first sun gear shaft of the first sun gear S1 coaxially therewith; on the other hand, the output shaft of the engine ICE is connected to, for example, a housing of the transmission via the second brake B2, so that the output shaft of the engine ICE is fixed with respect to, for example, the housing of the transmission after the second brake B2 is engaged, thereby locking the output shaft of the engine and thus the first sun gear S1.
In the present embodiment, the first electric motor MG1 is provided on the opposite side (left side in fig. 1 a) of the transmission from the side on which the engine ICE is provided. As described above, the input/output shaft of the first motor MG1 is directly connected to the second sun gear shaft of the second sun gear S2 coaxially therewith, so that the driving force/torque can be transmitted bidirectionally between the first motor MG1 and the second sun gear shaft. In this way, in the case where the first electric machine MG1 is supplied with electric power from a battery (not shown) as an example of an energy storage device, the first electric machine MG1 can transmit torque to the second sun gear shaft as a motor, and in the case where the first electric machine MG1 obtains torque from the second sun gear shaft, the first electric machine MG1 can charge the battery as a generator.
In the present embodiment, the second electric motor MG2 is provided on the same side as the engine ICE (right side in fig. 1 a) with respect to the transmission. As described above, the input/output shaft of the second motor MG2 is drivingly coupled to the first ring gear R1 via the input/output gear G4, so that the driving force/torque can be transmitted bidirectionally between the second motor MG2 and the first ring gear R1. In this way, in the case where the second electric machine MG2 is supplied with electric energy from a battery (not shown) as an example of an energy storage device, the second electric machine MG2 can transmit torque to the first ring gear R1 as a motor, and in the case where the second electric machine MG2 obtains torque from the first ring gear R1, the second electric machine MG2 can charge the battery as a generator. In addition, the input/output shaft of the second motor MG2 is connected to, for example, a case of the transmission via a third brake B3, and the input/output shaft of the second motor MG2 is fixed with respect to, for example, the case of the transmission after the third brake B3 is engaged so that the first ring gear R1 is locked and fixed.
As is apparent from the above description, in the present embodiment, the second carrier P2 and the second ring gear R2 are linked via the first brake B1, so that the second carrier P2 and the second ring gear R2 are lock-fixed to each other after the first brake B1 is engaged. The output shaft of the engine ICE is connected to, for example, a housing of the transmission via a second brake B2, so that engagement of the second brake B2 fixes the output shaft of the engine ICE relative to, for example, the housing of the transmission, and thus locks the first sun gear S1 in place. The input/output shaft of the second electric machine MG2 is connected to, for example, a housing of the transmission via a third brake B3, so that engagement of the third brake B3 then fixes the input/output shaft of the second electric machine MG2 relative to, for example, the housing of the transmission, and thus locks the first ring gear R1 in place. In this way, the four-wheel drive system can be flexibly controlled to be in different working modes through the three brakes B1, B2 and B3. The three brakes B1, B2, B3 may be transmission brakes, clutches, or the like.
The specific structure of the four wheel drive system according to the first embodiment of the present invention has been described above in detail, and the operation mode of the four wheel drive system will be described below.
(operation mode of the four-wheel drive system according to the first embodiment of the invention)
The four wheel drive system according to the first embodiment of the present invention shown in fig. 1a further includes a control module (not shown) capable of controlling the four wheel drive system in two four wheel drive modes, a timely four wheel drive mode and a time-share four wheel drive mode, by controlling the engagement/disengagement of the first brake B1. Specifically, when the second carrier P2 is locked and fixed with the second ring gear R2 after the first brake B1 is engaged, the four-wheel drive system realizes the time-sharing four-wheel drive mode; when the lock fixation of the second carrier P2 and the second ring gear R2 is released after the first brake B1 is off, the four-wheel drive system realizes the timely four-wheel drive mode. In the above two four-wheel drive modes, a plurality of sub-modes can be realized depending on the situation.
The operating states of the three brakes B1, B2, B3 in the two four-wheel drive modes and the main sub-modes in the two four-wheel drive modes are shown in table 1 below.
TABLE 1
The timely four-wheel drive mode of the four-wheel drive system according to the present invention will be described below with reference to table 1.
When the four wheel drive system according to the present invention is in the timely four wheel drive mode, the first brake B1 is off. According to the torque analysis lever diagram in fig. 1b, the planetary carriers P1 and P2 of the two planetary gear mechanisms transmit torque to the first driveshaft FD1 as the main power output shaft, driving the vehicle.
If the adhesion force of the first driveshaft FD1 is sufficient, the first motor MG1 is in the follow-up state and outputs no torque, all of which is output through the first driveshaft FD 1. At this time, the four-wheel drive system according to the present invention is in the two-wheel drive state.
If the first drive shaft FD1 slips due to insufficient adhesion, the rotation speed of the first drive shaft FD1 increases, the first motor MG1 outputs negative torque to limit slip of the first drive shaft FD1, and a part of the torque for driving is transmitted from the first drive shaft FD1 to the second drive shaft FD 2. At this time, the four-wheel drive system according to the present invention is in a four-wheel drive state. In this state, a part of the excessive torque of the first drive shaft FD1 is transmitted to the second drive shaft FD2 for assist drive, and a part of the excessive torque drives the first motor MG1 to recover energy to the battery.
The timely four-wheel drive mode is suitable for daily driving, has good smoothness and economy, and can quickly and accurately respond to the situation that the tire slips to realize escaping. Under the timely four-wheel drive mode, the following formula is satisfied:
Tout1＝TICE+TMG2+(1+i2)TMG1and Tout2＝-i2TMG1
Wherein i2For the gear ratio from the second sun gear S2 to the second ring gear R2 when the second planet carrier P2 is locked fixed, TICETorque of the first sun gear S1, TMG1Torque of the second sun gear S2, TMG2Torque of the first ring gear R1, Tout1Is the output torque, T, of the first planet carrier P1out2Is the output torque of the second ring gear R2.
Further, the sub-modes when the four wheel drive system according to the invention is in the timely four wheel drive mode will be explained with reference to table 1.
When the four-wheel drive system according to the present invention is in the timely four-wheel drive mode, and the second brake B2 is engaged and the third brake B3 is disengaged, the four-wheel drive system can achieve the electric-only drive mode. At this time, both the output shaft of the engine ICE and the first sun gear S1 are locked and fixed. When the second motor MG2 operates alone, the four-wheel drive system according to the invention can be in a two-wheel drive state; the four-wheel drive system according to the invention can be in the four-wheel drive state when the first motor MG1 and the second motor MG2 are simultaneously operated.
When the four-wheel drive system according to the present invention is in the timely four-wheel drive mode, and the second brake B2 is disengaged and the third brake B3 is engaged, the four-wheel drive system is able to achieve the engine-only drive mode. At this time, both the input/output shaft of the second motor MG2 and the first ring gear R1 are locked and fixed. The engine ICE is operated and the four-wheel drive system according to the invention can be in a two-wheel drive state.
When the four-wheel drive system according to the present invention is in the timely four-wheel drive mode and both the second brake B2 and the third brake B3 are off, the four-wheel drive system can achieve the power split mode. At this time, the engine ICE is operated under the optimum condition, the first electric motor MG1 is operated to output a negative torque, and the second electric motor MG2 adjusts its output torque according to the torque distribution between the first drive shaft FD1 and the second drive shaft FD2, etc., the four-wheel drive system according to the present invention can be in the four-wheel drive state.
The time-sharing four-wheel drive mode of the four-wheel drive system according to the present invention will be described with reference to table 1.
When the four-wheel drive system according to the invention is in the split four-wheel drive mode, the first brake B1 is engaged. According to the moment analysis lever diagram of fig. 1c, the torque is equally distributed to the first drive shaft FD1 and the second drive shaft FD 2. Once the adhesion force of one of the first driving shaft FD1 and the second driving shaft FD2 is reduced, the torque is transferred to the other one having a high adhesion force. In this mode, the vehicle has a strong off-road escaping capability.
Further, sub-modes when the four wheel drive system according to the present invention is in the time-sharing four-wheel drive mode will be explained with reference to table 1.
When the four-wheel drive system according to the invention is in the time-sharing four-wheel drive mode, and the second brake B2 is engaged and the third brake B3 is disengaged, the four-wheel drive system can realize the electric-only drive mode. At this time, both the output shaft of the engine ICE and the first sun gear S1 are locked and fixed. The first motor MG1 and/or the second motor MG2 operate, and the four-wheel drive system according to the invention can be in a four-wheel drive state.
When the four-wheel drive system according to the present invention is in the time-sharing four-wheel drive mode, and the second brake B2 is disengaged and the third brake B3 is engaged, the four-wheel drive system can achieve the engine-only drive mode. At this time, both the input/output shaft of the second motor MG2 and the first ring gear R1 are locked and fixed. With the engine ICE in operation, the four-wheel drive system according to the invention can be in a four-wheel drive state.
When the four-wheel drive system according to the invention is in the time-sharing four-wheel drive mode, and both the second brake B2 and the third brake B3 are off, the four-wheel drive system can realize the parallel hybrid drive mode. At this time, the engine ICE is operated, the first motor MG1 and/or the second motor MG2 are operated, and the respective drive sources transmit torque to the respective drive shafts through the respective transmission paths, respectively, and the four-wheel drive system according to the present invention can be placed in a four-wheel drive state.
The structure and the operation mode of the four wheel drive system according to the first embodiment of the present invention have been described above, and the structure and the operation mode of the four wheel drive system according to the second embodiment of the present invention will be described below.
(construction and operation mode of four-wheel drive system according to second embodiment of the invention)
The basic structure of the four-wheel drive system according to the second embodiment of the present invention is substantially the same as that of the four-wheel drive system according to the first embodiment of the present invention, and only the differences therebetween will be described below. As shown in fig. 2a, in the four-wheel drive system according to the second embodiment of the invention, the engine ICE is drivingly coupled to the first sun gear S1 via, for example, a gearbox GB of a conventional transmission, the second electric machine MG2, the second brake B2 and the third brake B3 are omitted in comparison with the first embodiment, and the first ring gear R1 is locked and fixed to, for example, a case of the transmission.
The four-wheel drive system according to the second embodiment of the invention is also capable of realizing the four-wheel drive-in-time mode (first brake B1 off) and the four-wheel drive-in-time mode (first brake B1 on) similarly as in the first embodiment, based on the engagement/disengagement of the first brake B1, and fig. 2B and 2c show moment lever analysis diagrams in the four-wheel drive-in-time mode and the four-wheel drive-in-time mode, respectively. Since similar to the first embodiment, the details of the timely four-wheel drive mode and the time-sharing four-wheel drive mode of the four-wheel drive system of the present embodiment will not be described in detail herein.
By adopting the four wheel drive system according to the second embodiment of the present invention, the technical idea of the present invention can be easily engaged with a driven vehicle.
While the above description details the embodiments of the present invention, the following points should be described.
I. The four-wheel drive system according to the present invention has the following main features:
a four-wheel drive system capable of realizing a timely four-wheel drive mode is designed based on a hybrid power system comprising two parallel planetary gear mechanisms, the timely four-wheel drive mode is realized through a torque distribution strategy of the hybrid power system, and a power splitting mode is further combined with the timely four-wheel drive mode;
the four-wheel drive system according to the present invention can switch the drive mode between the time-sharing four-wheel drive mode and the timely four-wheel drive mode by engagement/disengagement of the brake;
the four-wheel drive system according to the present invention enables torque distribution between two drive shafts by a speed-adjustable motor (the first motor in the above-described embodiment) in cooperation with a planetary gear mechanism, and establishes a set of four-wheel drive system implemented by a motor (different from the conventional mechanical control); and
the speed regulating motor not only realizes the torque distribution function between the two driving shafts, but also has the functions of regulating the working point of the engine and the generator, and can actively respond to different required working conditions.
By adopting the four-wheel drive system according to the invention, the following advantageous effects can also be achieved:
the four-wheel drive system is completely developed based on a power split hybrid power system, an additional complex mechanical structure is not required to be added, and the structure is simple;
the four-wheel drive system can be switched between the timely four-wheel drive mode and the time-sharing four-wheel drive mode according to requirements so as to meet the requirements of different road conditions, and the advantages of the two drive modes are utilized for complementation;
the four-wheel drive system of the invention realizes the torque distribution function between the two driving shafts by using the motor torque control, thus having the advantages of quicker response, higher precision, simpler control and the like compared with the traditional mechanical control, and simultaneously having no defect that the traditional timely four-wheel drive system is easy to lose efficacy;
when the four wheel drive system according to the invention is in the right-of-time four wheel drive mode, it is theoretically possible to transmit more than 50% of the torque to the non-main drive axle; and
the four-wheel drive system according to the present invention was developed based on a hybrid system, but may be adapted to be applied to a conventional powered vehicle as well.
In the formula referred to in the invention, TMG1It refers to the torque of the second sun gear S2 connected to the first motor MG1 rather than the torque of the first motor MG1 because the torque and rotational speed of the first motor MG1 differ from the torque of the second sun gear S2 as a result of the ratio of the input/output shaft of the first motor MG1 and the structure of the second sun gear shaft of the second sun gear S2 that may be present as a coaxial connector or the like. Similarly, other parameters have similar conditions.
Claims (10)
1. A four wheel drive system, comprising:
a transmission including a first planetary gear mechanism and a second planetary gear mechanism that are coaxially arranged, the first planetary gear mechanism including a first sun gear (S1), a plurality of first planet gears (PG1), a first carrier (P1), and a first ring gear (R1), the second planetary gear mechanism including a second sun gear (S2), a plurality of second planet gears (PG2), a second carrier (P2), and a second ring gear (R2), the first carrier (P1) and the second carrier (P2) being fixed to each other;
an engine (ICE), an output shaft of the engine (ICE) being in transmission coupling with a first sun gear shaft of the first sun gear (S1) or being directly connected in a coaxial manner;
a first electric machine (MG1), an input/output shaft of the first electric machine (MG1) being drivingly coupled or directly coaxially connected with a second sun gear shaft of the second sun gear (S2); and
a first brake (B1), the first brake (B1) being disposed between the second carrier (P2) and the second ring gear (R2), and the first brake (B1) being engaged to thereby lock-fix the second carrier (P2) and the second ring gear (R2) to each other,
wherein the first ring gear (R1) is locked fixed or drivingly coupled to an additional power source other than the engine (ICE) and the first electric machine (MG1), the first carrier (P1) is configured to transmit torque to a first drive shaft (FD1) of a vehicle, and the second ring gear (R2) is configured to transmit torque to a second drive shaft (FD2) of the vehicle.
2. A four-wheel drive system according to claim 1, wherein the additional power source is a second electric machine (MG 2).
3. A four wheel drive system as defined in claim 2, further comprising:
a second brake (B2) capable of locking the first sun gear (S1) fixed after engagement of the second brake (B2); and
a third brake (B3), the first ring gear (R1) can be locked and fixed after the third brake (B3) is engaged.
4. A four-wheel drive system according to claim 3, characterized in that the first brake (B1), the second brake (B2) and/or the third brake (B3) are clutches.
5. A four wheel drive system according to any of claims 1 to 4, further comprising a control module capable of controlling the four wheel drive system to cause the four wheel drive system to achieve a time-sharing four-wheel-drive mode and a timely four-wheel-drive mode,
the first brake (B1) is engaged so that the second carrier (P2) and the second ring gear (R2) are lock-fixed to each other to achieve the time-sharing four-wheel drive mode, and
the first brake (B1) is off so that the second carrier (P2) and the second ring gear (R2) are released from the lock-up fixation to allow the four-wheel drive system to achieve the timely four-wheel drive mode.
6. A four-wheel drive system according to claim 5, characterized in that when the four-wheel drive system realizes the right-of-time four-wheel drive mode, the four-wheel drive system is capable of realizing a two-wheel drive state when the first electric motor (MG1) is not outputting torque, and a four-wheel drive state when the first electric motor (MG1) is outputting negative torque.
7. A four wheel drive system according to claim 5, wherein when said four wheel drive system is implementing said four wheel drive mode in time,
satisfy Tout1＝TICE+TMG2+(1+i2)TMG1And Tout2＝-i2TMG1
Wherein i2Is a gear ratio from the second sun gear (S2) to the second ring gear (R2) when the second carrier (P2) is locked fixed, TICEIs the torque, T, of the first sun gear (S1)MG1Is the torque, T, of the second sun gear (S2)MG2Is the torque, T, of the first ring gear (R1)out1Is the output torque, T, of the first planet carrier (P1)out2Is the output torque of the second ring gear (R2).
8. A four wheel drive system according to claim 5 as dependent on claim 3 or 4, wherein when said four wheel drive system is implementing said four wheel drive in-time mode, said four wheel drive system is capable of implementing a power split drive mode in which both said second brake (B2) and said third brake (B3) are off.
9. A four-wheel drive system according to claim 5, characterised in that the second planet carrier (P2) is rigidly connected to the second ring gear (R2) when the four-wheel drive system is in the part-time four-wheel drive mode, the four-wheel drive system always achieving a four-wheel drive condition.
10. A vehicle characterized in that the vehicle includes the four-wheel drive system according to any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910699973.1A CN112297819A (en) | 2019-07-31 | 2019-07-31 | Four-wheel drive system and vehicle |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910699973.1A CN112297819A (en) | 2019-07-31 | 2019-07-31 | Four-wheel drive system and vehicle |
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| CN112297819A true CN112297819A (en) | 2021-02-02 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114935002A (en) * | 2022-06-25 | 2022-08-23 | 北京博格华纳汽车传动器有限公司 | Overheating automatic gear shifting method, device, equipment and medium based on combined transfer case |
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2019
- 2019-07-31 CN CN201910699973.1A patent/CN112297819A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114935002A (en) * | 2022-06-25 | 2022-08-23 | 北京博格华纳汽车传动器有限公司 | Overheating automatic gear shifting method, device, equipment and medium based on combined transfer case |
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