WO2021073184A1

WO2021073184A1 - Two-gear variable-speed bridge driving system without driving force interruption

Info

Publication number: WO2021073184A1
Application number: PCT/CN2020/103043
Authority: WO
Inventors: 刘磊; 王天斌; 钟虎; 翟青泉
Original assignee: 舍弗勒技术股份两合公司; 刘磊
Priority date: 2019-10-14
Filing date: 2020-07-20
Publication date: 2021-04-22
Also published as: CN112721619A

Abstract

A two-gear variable-speed bridge driving system without driving force interruption, comprising a duplex planetary gear set (PG), a sun gear of the duplex planetary gear set (PG) being meshed with a second planetary gear (G2), a first planetary gear (G1) being meshed with a first gear ring (R1), and the second planetary gear (G2) being meshed with a second gear ring (R2); an outer hub of a first clutch (C1) is fixed, and an inner hub of the first clutch (C1) cannot be rotatingly connected to the first gear ring (R1); an outer hub of a second clutch (C2) is fixed, and an inner hub of the second clutch (C2) cannot be rotatingly connected to the second gear ring (R2); and the output torque of a motor (E) is transmitted to the sun gear, and the output torque of a planet carrier is transmitted to a differential (D). The gear shifting operation of the driving system is achieved by two independent clutches (C1, C2); moreover, the system has a simple structure, and driving force may not be interrupted during gear shifting.

Description

Two-speed transmission bridge drive system without power interruption

References to related applications

The present invention claims the priority of the invention patent application filed in China on October 14, 2019, entitled "Two-speed transmission bridge drive system without power interruption", and the application number is 201910971043.7. The entire content of the application is incorporated by reference. Into this article.

Technical field

The present invention relates to the field of motor vehicles, in particular to the field of vehicle transmissions, in particular to an electric bridge drive system in a pure electric vehicle or a hybrid vehicle, and more particularly to a two-speed transmission bridge drive system without power interruption.

Background technique

For electric vehicles, including pure electric vehicles and hybrid (oil-electric hybrid) vehicles, the electric drive methods include central motor drive and wheel hub motor drive. A common arrangement form of the central motor drive system is also called an electric bridge (eAxle) drive system.

For a transmission of an electric vehicle that can provide two speed gears, a gear shifting method in the prior art is to use a synchronizer to shift gears. The disadvantage of this shifting method is that when one gear is disengaged into neutral and the other gear has not yet been engaged, no power is transmitted out of the transmission. This loss of power during gear shifting can lead to a bad driving experience.

Another way of shifting in the prior art uses a clutch. For example, the Chinese utility model patent CN205859059U discloses a dual-clutch planetary row type pure electric vehicle transmission. 1, in this solution, the motor E and the differential D are arranged coaxially. Between the motor E and the differential D, there is a dual clutch DC and a dual planetary gear set PG1. The dual planetary gear set PG1 includes two sets of planet gears arranged side by side and arranged in parallel in the axial direction. Each set of planet gears meshes with a sun gear, and the two sets of planet gears are connected to the same planet carrier. The two inner hubs of the dual clutch DC are respectively connected to the two sun gears of the dual planetary gear set PG1 through the inner shaft SI and the outer shaft SO nested with each other. By controlling the engagement state of the dual clutch DC, the transmission ratio of the dual planetary gear set PG1 can be changed to realize the function of two-speed transmission. However, this solution has the following disadvantages:

(i) The dual-clutch DC has a large number of parts and complex structure. Correspondingly, the control method of the dual-clutch DC is complicated and the cost is high;

(ii) The device corresponding to the design scheme occupies a large axial space;

(iii) Since the outer shaft SO is sleeved on the outer circumference of the inner shaft SI, the outer shaft SO is supported by the inner shaft SI, and the outer shaft SO needs to be able to rotate relative to the inner shaft SI. This is the position accuracy of the outer shaft SO and the inner shaft SI Put forward higher requirements;

(iv) The transmission ratio that a single dual planetary gear set PG1 can provide is limited. When the transmission ratio is not large enough, the output torque of the motor E needs to be increased, resulting in an increase in system cost.

Summary of the invention

The purpose of the present invention is to overcome or at least alleviate the above-mentioned shortcomings of the prior art, and provide a two-speed transmission bridge drive system with simple structure and convenient control without power interruption.

The present invention provides a two-speed transmission bridge drive system without power interruption, which includes a motor, a gear set, a first clutch, a second clutch and a differential.

The gear set includes a dual planetary gear set, the dual planetary gear set includes a sun gear, a first planet gear, a first ring gear, a second planet gear, a second ring gear, and a planet carrier. The sun gear and The second planet gear meshes, the first planet gear meshes with the first ring gear, the second planet gear meshes with the second ring gear, the first planet gear and the second planet The wheels are arranged side by side in the axial direction of the motor so as not to rotate relatively; wherein,

The outer hub of the first clutch is fixed, and the inner hub of the first clutch is connected to the first ring gear so as not to rotate relatively; the outer hub of the second clutch is fixed, and the inner hub of the second clutch is connected to The second ring gear cannot be connected in a relatively rotating manner;

The output torque of the motor is transmitted to the sun gear, and the output torque of the planet carrier is transmitted to the differential;

When the inner hub and outer hub of the first clutch are in an engaged state, and the inner hub and outer hub of the second clutch are in a disengaged state, the electric bridge drive system is in a gear; When the inner hub and the outer hub are in a separated state, and the inner hub and the outer hub of the second clutch are in an engaged state, the electric bridge drive system is in another gear.

In at least one embodiment, the gear set further includes a spur gear set including a first spur gear and a second spur gear that mesh with each other,

The first spur gear and the sun gear are arranged with the same rotation axis, and the second spur gear and the output half shaft of the differential are arranged with the same rotation axis,

The first spur gear is non-rotatably connected with the planet carrier, and the second spur gear is non-rotatably connected with the differential housing of the differential.

In at least one embodiment, the system further includes a motor shaft and a gearbox input shaft,

The rotor of the motor is connected with the motor shaft so as not to rotate relative to each other, and the sun gear is connected with the input shaft of the gearbox so as not to rotate relative to each other,

The motor shaft and the gearbox input shaft are integrally formed into the same main shaft.

In at least one embodiment, the two ends of the main shaft in the axial direction are respectively supported by a first bearing and a third bearing, and the middle part of the main shaft in the axial direction is also supported by a second bearing. The second bearing is located between the motor and the gear set in the axial direction.

In at least one embodiment, in the axial direction, the third bearing at least partially coincides with the first planetary gear; or

In the axial direction, the second bearing at least partially coincides with the first planetary gear.

In at least one embodiment, in the axial direction,

The first clutch and the first ring gear at least partially overlap, and/or

The second clutch and the second ring gear at least partially overlap.

In at least one embodiment, in the radial direction of the motor,

The diameter of the motor is greater than the diameter of the first clutch, and/or

The diameter of the motor is larger than the diameter of the second clutch.

In at least one embodiment, the first clutch is a multi-plate clutch, and/or the second clutch is a multi-plate clutch.

In at least one embodiment, the diameter of the second planetary gear is larger than the diameter of the first planetary gear.

In at least one embodiment, the differential is located on the radially outer side of the electric motor, and the output half shaft of the differential is arranged in parallel with the motor shaft of the electric motor.

According to the two-speed transmission bridge drive system without power interruption of the present invention, the shifting operation is completed by two independent clutches, the system structure is simple, and there is no power interruption during the shifting process.

Description of the drawings

Figure 1 is a schematic diagram of a known two-speed electric axle drive system.

Fig. 2 is a schematic diagram of a two-speed transmission bridge drive system without power interruption according to the first embodiment of the present invention.

3 and 4 are schematic diagrams of power transmission paths of the electric bridge drive system shown in FIG. 2 in two different gears.

Fig. 5 is a schematic diagram of a two-speed transmission bridge drive system without power interruption according to a second embodiment of the present invention.

Description of Reference Signs

E motor; SI inner shaft; SO outer shaft; S1 motor shaft; S2 gearbox input shaft;

DC double clutch; C1 first clutch; C2 second clutch;

PG, PG1 double planetary gear set; G1 first planetary gear; G2 second planetary gear; R1 first ring gear; R2 second ring gear;

SG1 first spur gear; SG2 second spur gear;

D differential; B1 first bearing; B2 second bearing; B3 third bearing;

A axial direction; R radial direction.

Detailed ways

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present invention, and are not used to exhaust all possible ways of the present invention, nor are they used to limit the scope of the present invention.

Unless otherwise specified, referring to Figure 2, A represents the axial direction of the electric bridge drive system, and the axial direction A is consistent with the axial direction of the motor and the double planetary gear set in the electric bridge drive system; R represents the radial direction of the electric bridge drive system , The radial direction R is consistent with the radial direction of the motor and the dual planetary gear set in the electric bridge drive system.

(First embodiment)

First, the electric bridge drive system according to the first embodiment of the present invention will be described with reference to FIGS. 2 to 4.

The electric bridge drive system according to the present invention includes a motor E, a motor shaft S1, a gearbox input shaft S2, a first clutch C1, a second clutch C2, a gear set, and a differential D. The gear set includes a dual planetary gear set PG and a spur gear set. The spur gear set includes a first spur gear SG1 and a second spur gear SG2. The spur gear referred to in the present invention includes a spur gear and a helical gear; in this embodiment, it is preferable to use a spur gear in the form of a helical gear, that is, a helical cylindrical gear.

The stator of the motor E is fixed to the housing, and the rotor of the motor E is connected to the motor shaft S1 in a torsion-resistant (non-rotatable) manner.

The motor shaft S1 and the gearbox input shaft S2 are connected in a torsion-resistant manner, and preferably, the motor shaft S1 and the gearbox input shaft S2 are formed as an integrated shaft. For ease of expression, this integrated shaft (single shaft) is also Referred to as the spindle.

Preferably, the main shaft is supported by three bearings. The first bearing B1 and the third bearing B3 are respectively arranged at the two ends of the main shaft in the axial direction A, the second bearing B2 is located between the first bearing B1 and the third bearing B3 in the axial direction A, and the second bearing B2 is located between the first bearing B1 and the third bearing B3 in the axial direction A. The bearing B2 is located between the motor E and the gear set (the dual planetary gear set PG and the spur gear set) in the axial direction A.

The dual planetary gear set PG includes a sun gear and two sets of planetary gears (first planetary gear G1 and second planetary gear G2) juxtaposed in the axial direction A. The sun gear is connected to the gearbox input shaft S2 in a torsion-resistant manner, and one of the two sets of planetary gears meshes with the sun gear. The two sets of planet wheels are connected in a torsion-resistant manner.

In this embodiment, the sun gear meshes with the second planetary gear G2, and the second planetary gear G2 meshes with the second ring gear R2. The first planetary gear G1 meshes with the first ring gear R1, and the first planetary gear G1 is farther from the motor E in the axial direction A than the second planetary gear G2.

The first planetary gear G1 and the second planetary gear G2 are both connected to the same planet carrier.

Preferably, the diameter of the second planetary gear G2 is larger than the diameter of the first planetary gear G1, and the inner diameter of the second ring gear R2 is not smaller than (more preferably larger than) the inner diameter of the first ring gear R1. The sun gear meshes with the second planet gear G2 instead of the first planet gear G1, so that the double planetary gear set PG can have a greater reduction ratio; at the same time, it is also free from the radial inner side of the first planet gear G1 This part of the space can be used, for example, to set the third bearing B3 and its bearing seat, that is, in the axial direction A, the third bearing B3 can at least partially overlap the first planetary gear G1, thereby reducing the transmission的axial dimension.

The outer hub and inner hub of the first clutch C1 (two parts of the clutch that can be engaged or separated for transmitting or cutting off power) are respectively connected to the housing and the first ring gear R1 in a torsionally fixed manner. When the first clutch C1 is in the engaged state, the first ring gear R1 is connected to the housing in a torque-proof manner; when the first clutch C1 is in the disengaged state, the first ring gear R1 can rotate relative to the housing.

The outer hub and inner hub of the second clutch C2 are respectively connected to the housing and the second ring gear R2 in a torque-proof manner. When the second clutch C2 is in the engaged state, the second ring gear R2 is connected to the housing in a torque-proof manner; when the second clutch C2 is in the disengaged state, the second ring gear R2 can rotate relative to the housing.

Preferably, the first clutch C1 and the second clutch C2 are both multi-plate clutches, that is, the clutch has multiple friction plates that connect the outer hub and the inner hub to transmit power. The multi-plate clutch can reduce the radial direction of the clutch. The size in turn reduces the radial size of the dual planetary gear set.

Preferably, in the axial direction A, the first clutch C1 and the first ring gear R1 at least partially overlap, and the second clutch C2 and the second ring gear R2 at least partially overlap, which makes the two clutches (the first clutch C1 and The second clutch C2) does not occupy or occupy as little as possible the extra space in the axial direction inside the transmission, the space in the radial direction inside the transmission is reasonably used, and the axial size of the transmission is controlled.

Preferably, in the radial direction R, the diameter of the motor E is larger than the diameter of the double planetary gear set PG. More preferably, in the radial direction R, the diameter of the motor E is larger than the diameters of the first clutch C1 and the second clutch C2. This allows the two clutches to occupy no or as little space in the radial direction as possible inside the transmission, and the radial size of the transmission is controlled.

Preferably, since the two clutches are both partially connected to the housing, the actuator of the clutch (the first clutch C1 and/or the second clutch C2) can be integrated in the housing, for example, the piston of the actuator of the clutch can be arranged in the housing. In the groove of the cavity of the housing. Preferably, since the inner hub of the first clutch C1 is connected to the first ring gear R1, the inner hub of the first clutch C1 can be integrated into the first ring gear R1; since the inner hub of the second clutch C2 is connected to the second gear Ring R2, so the inner hub of the second clutch C2 can be integrated into the second ring gear R2.

The torque of the planet carrier is further transmitted to a spur gear set. The spur gear set is located between the motor E and the dual planetary gear set PG in the axial direction A.

The spur gear set includes a first spur gear SG1 and a second spur gear SG2 that mesh with each other. The first spur gear SG1 is sleeved on the outer circumference of the gearbox input shaft S2, and the first spur gear SG1 is connected to the planet carrier of the double planetary gear set PG in a torsion-resistant manner.

The second spur gear SG2 is sleeved on the outer circumference of an output half shaft of the differential D, and the second spur gear SG2 is connected to the differential housing in a torque-proof manner.

The number of teeth of the second spur gear SG2 is greater than the number of teeth of the first spur gear SG1.

In the radial direction R, the differential D is located on the radially outer side of the motor E, and the two output half shafts of the differential D are arranged in parallel with the main shaft.

Next, referring to FIGS. 3 and 4, the working mode of the electric bridge drive system according to this embodiment to realize two-speed transmission will be described.

(i) The first clutch C1 is engaged, and the second clutch C2 is disengaged

3, the first clutch C1 is in an engaged state, and the second clutch C2 is in a disengaged state.

At this time, the first ring gear R1 is fixed, and the second ring gear R2 is not fixed. The power input by the sun gear is output through the first planet gear G1 and the planet carrier.

The torque transmission path is: motor E, motor shaft S1, gearbox input shaft S2, sun gear of double planetary gear set PG, second planetary gear G2, first planetary gear G1, planet carrier, first spur gear SG1, The second spur gear SG2 to the differential D.

(ii) The first clutch C1 is disengaged, and the second clutch C2 is engaged

4, the first clutch C1 is in a disengaged state, and the second clutch C2 is in an engaged state.

At this time, the second ring gear R2 is fixed, and the first ring gear R1 is not fixed. The power input by the sun gear is output through the second planet gear G2 and the planet carrier.

The torque transmission path is: motor E, motor shaft S1, gearbox input shaft S2, second planetary gear G2, planet carrier, first spur gear SG1, second spur gear SG2 to differential D.

(Second embodiment)

Next, referring to FIG. 5, the bridge drive system according to the second embodiment of the present invention will be described.

The second embodiment is a modification of the first embodiment. The second embodiment differs from the first embodiment mainly in the orientation of the differential D and the arrangement structure of the gear set.

In this embodiment, the spur gear set is farther from the motor E in the axial direction A than the double planetary gear set PG, and the second spur gear SG2 is connected to the end of the differential housing that is farther from the motor E in the axial direction A.

Preferably, the first planetary gear G1 is arranged to be closer to the motor E in the axial direction A than the second planetary gear G2, which enables the part of the first planetary gear G1 to be vacant on the radial inner side closer to the second bearing B2, so that the second planetary gear G1 is located closer to the second bearing B2. The bearing B2 and its bearing seat can utilize the space radially inside the first planetary gear G1, that is, in the axial direction A, the second bearing B2 can at least partially overlap the first planetary gear G1, reducing the axial size of the transmission.

The present invention has at least one of the following advantages:

(i) The motor shaft S1 and the gearbox input shaft S2 can share the same shaft, which reduces the number of shafts of the electric bridge drive system and reduces the cost.

(ii) The main shaft can be supported on the shell by three bearings. The supporting relationship between the gears and the shafts in the system is simple, and no nested supporting shafts are needed. The supporting reliability is high and the cost is low. Vibration, Harshness, that is, noise, vibration and harshness) have good performance.

(iii) The combination of the dual planetary gear set PG and the spur gear set increases the transmission ratio of the system, and the high transmission ratio requires low output torque of the motor E, which saves the cost of the system.

(iv) Two separate clutches (the first clutch C1 and the second clutch C2) make full use of the axial and radial spaces inside the gearbox, and because the clutch is connected to the housing or gear, part of the clutch components can be Integrated in the housing or gear connected to it, the system structure is more compact and the cost is low.

(v) Since two clutches are used to switch gears, while one clutch is disengaged, the other clutch can be slowly engaged, so that power transmission is not interrupted during the shift.

(vi) Because the electric bridge drive system has a compact structure and a small footprint, this also leaves more space for the layout of other parts of the vehicle.

Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art can make various modifications to the above-mentioned embodiments of the present invention under the teaching of the present invention without departing from the scope of the present invention.

For example, although the first clutch C1 and the second clutch C2 shown in the drawings are both multi-plate clutches with multiple friction plates, the present invention does not limit the number of clutch friction plates.

Claims

A two-speed transmission bridge drive system without power interruption, which includes a motor (E), a gear set, a first clutch (C1), a second clutch (C2) and a differential (D),

The gear set includes a dual planetary gear set (PG), the dual planetary gear set (PG) includes a sun gear, a first planet gear (G1), a first ring gear (R1), a second planet gear (G2) ), a second ring gear (R2) and a planet carrier, the sun gear meshes with the second planet gear (G2), and the first planet gear (G1) meshes with the first ring gear (R1), The second planetary gear (G2) meshes with the second ring gear (R2), and the first planetary gear (G1) and the second planetary gear (G2) are in the axial direction of the motor (E) (A) The upper can not be arranged side by side with relative rotation; among them,

The outer hub of the first clutch (C1) is fixed, and the inner hub of the first clutch (C1) is connected to the first ring gear (R1) so as not to rotate relatively; the outer hub of the second clutch (C2) The hub is fixed, and the inner hub of the second clutch (C2) and the second ring gear (R2) are connected in a relatively non-rotatable manner;

The output torque of the motor (E) is transmitted to the sun gear, and the output torque of the planet carrier is transmitted to the differential (D);

When the inner hub and outer hub of the first clutch (C1) are in an engaged state, and the inner hub and outer hub of the second clutch (C2) are in a separated state, the electric bridge drive system is in a gear; when When the inner hub and outer hub of the first clutch (C1) are in a separated state and the inner hub and outer hub of the second clutch (C2) are in an engaged state, the electric bridge drive system is in another gear.
The electric bridge drive system according to claim 1, wherein the gear set further comprises a spur gear set, and the spur gear set includes a first spur gear (SG1) and a second spur gear (SG2) meshing with each other ,

The first spur gear (SG1) and the sun gear are arranged with the same axis of rotation, and the second spur gear (SG2) and the output shaft of the differential (D) are arranged with the same axis of rotation,

The first spur gear (SG1) is non-rotatably connected with the planet carrier, and the second spur gear (SG2) is non-rotatably connected with the differential housing of the differential (D).
The electric bridge drive system according to claim 1, wherein the system further comprises a motor shaft (S1) and a gearbox input shaft (S2),

The rotor of the motor (E) is connected to the motor shaft (S1) in a non-rotatable manner, and the sun gear is connected to the gearbox input shaft (S2) in a non-rotatable manner,

The motor shaft (S1) and the gearbox input shaft (S2) are integrally formed as the same main shaft.
The electric bridge drive system according to claim 3, wherein the two ends of the main shaft in the axial direction (A) are respectively supported by a first bearing (B1) and a third bearing (B3), and the The central part of the main shaft in the axial direction (A) is also supported by a second bearing (B2), and the second bearing (B2) is located on the motor (E) and the gear in the axial direction (A). Between groups.
The electric bridge drive system according to claim 4, characterized in that, in the axial direction (A), the third bearing (B3) at least partially coincides with the first planetary gear (G1); or

In the axial direction (A), the second bearing (B2) at least partially coincides with the first planetary gear (G1).
The electric bridge drive system according to claim 1, wherein in the axial direction (A),

The first clutch (C1) and the first ring gear (R1) at least partially overlap, and/or the second clutch (C2) and the second ring gear (R2) at least partially overlap.
The electric bridge drive system according to claim 1, characterized in that, in the radial direction (R) of the motor (E),

The diameter of the motor (E) is greater than the diameter of the first clutch (C1), and/or

The diameter of the motor (E) is larger than the diameter of the second clutch (C2).
The electric bridge drive system according to claim 1, wherein the first clutch (C1) is a multi-plate clutch, and/or the second clutch (C2) is a multi-plate clutch.
The electric bridge drive system according to claim 1, wherein the diameter of the second planetary gear (G2) is larger than the diameter of the first planetary gear (G1).
The electric bridge drive system according to claim 2, wherein the differential (D) is located outside the radial direction (R) of the motor (E), and the output of the differential (D) is half The shaft is arranged in parallel with the motor shaft (S1) of the motor (E).