CN112721619A

CN112721619A - Two-gear speed change bridge driving system without power interruption

Info

Publication number: CN112721619A
Application number: CN201910971043.7A
Authority: CN
Inventors: 刘磊; 王天斌; 钟虎; 翟青泉
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2019-10-14
Filing date: 2019-10-14
Publication date: 2021-04-30
Also published as: WO2021073184A1

Abstract

The invention provides a two-gear speed-changing bridge driving system without power interruption, which comprises a duplex planetary gear set (PG), wherein a sun gear of the duplex planetary gear set (PG) is meshed with a second planet gear (G2), a first planet gear (G1) is meshed with a first gear ring (R1), and a second planet gear (G2) is meshed with a second gear ring (R2); the outer hub of the first clutch (C1) is fixed, and the inner hub of the first clutch (C1) is connected with the first ring gear (R1) in a non-rotatable way; the outer hub of the second clutch (C2) is fixed, and the inner hub of the second clutch (C2) is connected with the second ring gear (R2) in a non-rotatable way; 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). According to the electric bridge driving system, the gear shifting operation is completed by two independent clutches, the system structure is simple, and no power interruption can be caused in the gear shifting process.

Description

Two-gear speed change bridge driving system without power interruption

Technical Field

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

Background

For electric vehicles, including pure electric vehicles and hybrid (hybrid electric vehicles), the electric driving mode includes two driving modes, namely central motor driving and hub motor driving. One common arrangement of a central motor drive system is also known as an electric bridge (eexle) drive system.

For a transmission of an electric vehicle that can provide two speed gears, one of the shifting methods in the prior art is to shift gears using a synchronizer. A disadvantage of this shifting scheme is that no power is transmitted out of the transmission during the time when one gear is disengaged into neutral and the other gear is not yet fully engaged. This loss of power during the shift can result in a poor driving experience.

Another prior art shift pattern uses a clutch. For example, chinese utility model patent CN205859059U discloses a double clutch planet row type pure electric vehicle transmission. Referring to fig. 1, in this solution, the electric machine E and the differential D are arranged coaxially. A double clutch DC and a double planetary gear set PG1 are provided between the motor E and the differential D. The double planetary gear set PG1 includes two sets of axially juxtaposed, parallel planet wheels, each set meshing with a respective sun wheel, the two sets being connected to the same planet carrier. The two inner hubs of the double clutch DC are connected to the two sun gears of the double planetary gear set PG1 via the inner shaft SI and the outer shaft SO, respectively, which are nested inside each other. By controlling the engagement state of the double clutch DC, the gear ratio of the double planetary gear set PG1 can be changed, and the function of two-gear speed change is achieved. However, this solution has the following drawbacks:

(i) the double-clutch DC has the advantages that the number of parts and the structure of the double-clutch DC are large, accordingly, the control mode of the double-clutch DC is complex, and the cost is high;

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

(iii) because the outer shaft SO is sleeved on the periphery of the inner shaft SI, the outer shaft SO is supported by the inner shaft SI, and the outer shaft SO needs to rotate relative to the inner shaft SI, which provides higher requirements for the position accuracy of the outer shaft SO and the inner shaft SI;

(iv) the single, double planetary gear set PG1 provides a limited gear ratio, requiring an increase in the output torque of electric machine E when the gear ratio is not large enough, resulting in increased system cost.

Disclosure of Invention

The present invention is directed to overcoming, or at least alleviating, the above-mentioned deficiencies of the prior art by providing a two-speed transmission bridge drive system without power interruption that is simple in structure and convenient to control.

The invention provides a two-gear speed changing bridge driving system without power interruption, which comprises a motor, a gear set, a first clutch, a second clutch and a differential mechanism,

the gear set comprises a duplex planetary gear set, the duplex planetary gear set comprises a sun gear, a first planet gear, a first gear ring, a second planet gear, a second gear ring and a planet carrier, the sun gear is meshed with the second planet gear, the first planet gear is meshed with the first gear ring, the second planet gear is meshed with the second gear ring, and the first planet gear and the second planet gear are arranged in parallel in the axial direction of the motor in a manner of being incapable of relatively rotating; wherein the content of the first and second substances,

the outer hub of the first clutch is fixed, and the inner hub of the first clutch is connected with the first gear ring in a non-rotatable mode; the outer hub of the second clutch is fixed, and the inner hub of the second clutch is connected with the second gear ring in a non-rotatable 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 mechanism;

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

In at least one embodiment, the gear set further comprises a spur gear set comprising first and second spur gears that intermesh,

said first spur gear being disposed with the same axis of rotation as said sun gear, said second spur gear being disposed with the same axis of rotation as an output half shaft of said differential,

the first spur gear is non-rotatably connected to the carrier, and the second spur gear is non-rotatably connected to a differential case of the differential.

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

the rotor of the motor is connected with the motor shaft in a non-rotatable way, the sun gear is connected with the input shaft of the gear box in a non-rotatable way,

the motor shaft and the gearbox input shaft are integrally formed as one and the same main shaft.

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

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

In the axial direction, the second bearing at least partially coincides with the first planet wheel.

In at least one embodiment, the first and second end portions are, in the axial direction,

the first clutch is at least partially coincident with the first ring gear, and/or

The second clutch is at least partially coincident with the second ring gear.

In at least one embodiment, the rotor is rotatable about a rotational axis,

the diameter of the electric machine is greater than the diameter of the first clutch, and/or

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

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

In at least one embodiment, the diameter of the second planet is greater than the diameter of the first planet.

In at least one embodiment, the differential is located radially outward of the motor, with an output half shaft of the differential being disposed parallel to a motor shaft of the motor.

According to the two-gear speed change bridge driving system without power interruption, the gear shifting operation is completed by two independent clutches, the system structure is simple, and no power interruption can be caused in the gear shifting process.

Drawings

FIG. 1 is a schematic diagram of a known two-speed electric bridge drive system.

Fig. 2 is a schematic diagram of a two-speed, power-interrupt-free, variable speed bridge drive system according to a first embodiment of the present invention.

Fig. 3 and 4 are schematic diagrams of the 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, power-interrupt-free, variable speed bridge drive system according to a second embodiment of the present invention.

Description of the reference numerals

E, a motor; an SI inner shaft; an SO outer shaft; s1 motor shaft; s2 gearbox input shaft;

a DC dual clutch; a first clutch of C1; a second clutch of C2;

PG, PG1 double planetary gear sets; g1 first planet; g2 second planet; r1 first ring gear; r2 second ring gear;

SG1 first spur gear; SG2 second spur gear;

a differential mechanism D; b1 first bearing; b2 second bearing; b3 third bearing;

axial direction A; r is radial.

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.

Referring to fig. 2, unless otherwise noted, a represents the axial direction of the electric bridge drive system, which is coincident with the axial direction of the electric motor and the duplex planetary gear set in the electric bridge drive system; r represents the radial direction of the bridge drive system, which is coincident with the radial direction of the motor and the duplex planetary gear set in the bridge drive system.

(first embodiment)

A bridge driving system according to a first embodiment of the present invention will be described first with reference to fig. 2 to 4.

The 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 double planetary gear set PG and a spur gear set including a first spur gear SG1 and a second spur gear SG 2. The spur gear, namely the cylindrical gear, comprises a spur gear and a helical gear; in the present embodiment, a spur gear in the form of a helical gear, that is, a helical cylindrical gear is preferably used.

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

The motor shaft S1 is non-rotatably connected to the gearbox input shaft S2 and the motor shaft S1 is preferably formed as an integral shaft with the gearbox input shaft S2, which integral shaft (single shaft) is also referred to as the main shaft for convenience of description.

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

The double planetary gear set PG includes one 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 in a rotationally fixed manner to the gearbox input shaft S2, and one of the two sets of planet wheels meshes with the sun gear. The two groups of planet wheels are connected in a torsion-proof manner.

In the present 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 electric machine E than the second planetary gear G2 in the axial direction a.

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

Preferably, the diameter of the second planet gears G2 is larger than the diameter of the first planet gears G1, and the inner diameter of the second ring gear R2 is not smaller (more preferably larger) than the inner diameter of the first ring gear R1. The sun gear meshes with the second planetary gear G2, and does not selectively mesh with the first planetary gear G1, so that the duplex planetary gear set PG can have a larger reduction ratio; at the same time, more space is also available radially inside the first planet wheel G1, which can be used, for example, for arranging the third bearing B3 and its bearing seat, i.e., in the axial direction a, the third bearing B3 can at least partially coincide with the first planet wheel G1, so that the axial size of the transmission is reduced.

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

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

Preferably, the first clutch C1 and the second clutch C2 are both multi-plate clutches, i.e., the friction plates of the clutches that engage the outer and inner hubs to transmit power have multiple plates, which can reduce the radial size of the clutches and thus the radial size of the tandem planetary gear set.

Preferably, in the axial direction a, the first clutch C1 and the first ring gear R1 are at least partially overlapped, and the second clutch C2 and the second ring gear R2 are at least partially overlapped, so that the two clutches (the first clutch C1 and the second clutch C2) do not occupy or occupy as little extra space in the axial direction inside the transmission as possible, the space in the radial direction inside the transmission is reasonably utilized, and the axial size of the transmission is controlled.

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

Preferably, since both clutches are partially connected to the housing, the actuator of the clutch (first clutch C1 and/or second clutch C2) may be integrated into the housing, e.g., the piston of the actuator of the clutch may be disposed in a groove in the housing interior cavity. 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 may be integrated into the first ring gear R1; since the inner hub of the second clutch C2 is connected to the second ring gear R2, the inner hub of the second clutch C2 may be integrated to the second ring gear R2.

The torque of the carrier is further transferred to a spur gear set. The spur gear set is located between the motor E and the double 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 intermesh. The first spur gear SG1 is sleeved on the outer periphery of the gearbox input shaft S2, and the first spur gear SG1 is connected with the planet carrier of the duplex planetary gear set PG in a torque-proof manner.

The second spur gear SG2 is fitted around the outer periphery of one output half shaft of the differential D, and the second spur gear SG2 is connected to the differential case in a torque-proof manner.

The number of teeth of the second spur gear SG2 is larger than that of the first spur gear SG 1.

In the radial direction R, the differential D is located radially outside the electric machine E, and two output half shafts of the differential D are arranged in parallel with the main shaft.

Next, the operation of the bridge drive system according to the present embodiment to realize two-speed gear shifting will be described with reference to fig. 3 and 4.

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

Referring to fig. 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 from the sun gear is output via the first planetary gear G1 and the carrier.

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

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

Referring to fig. 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 via the second planetary gear G2 and the carrier.

The torque transmission path is in turn: the motor E, the motor shaft S1, the gearbox input shaft S2, the second planet wheel G2, the planet carrier, a first spur gear SG1, a second spur gear SG2 and the differential D.

(second embodiment)

Next, a bridge driving system according to a second embodiment of the present invention will be described with reference to fig. 5.

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 of the gear sets.

In this embodiment, the spur gear set is farther from the electric 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 case that is farther from the electric motor E in the axial direction a.

Preferably, the first planet wheel G1 is arranged closer to the electric machine E than the second planet wheel G2 in the axial direction a, which enables the portion of the first planet wheel G1 that is free radially inside to be close to the second bearing B2, so that the second bearing B2 and its bearing seat can utilize the space radially inside the first planet wheel G1, i.e. in the axial direction a, the second bearing B2 can at least partially coincide with the first planet wheel G1, reducing the axial size of the transmission.

The 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, so that the number of shafts of a bridge driving system is reduced, and the cost is reduced.

(ii) The main shaft can be supported in the shell by three bearings, the supporting relation between each gear and the shaft in the system is simple, a nested supporting shaft is not needed, the supporting reliability is high, the cost is low, and the vehicle has better performance in the aspects of Noise, Vibration and Harshness (NVH).

(iii) The combination of the double planetary gear set PG and the spur gear set enables the transmission ratio of the system to be increased, the requirement on the output torque of the motor E is low due to the high transmission ratio, and the cost of the system is saved.

(iv) The two separate clutches (the first clutch C1 and the second clutch C2) fully utilize the axial and radial space inside the gear box, and because the clutches are connected to the shell or the gear, partial elements of the clutches can be integrated in the shell or the gear connected with the clutches, so that the system structure is more compact and the cost is low.

(v) Because two clutches are used for realizing gear shifting, one clutch can be disengaged while the other clutch can be slowly engaged, so that the power transmission is not interrupted in the gear shifting process.

(vi) Because the bridge driving system has compact structure and small occupied space, the bridge driving system also leaves more space for arranging other parts of the vehicle.

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

For example: although the first clutch C1 and the second clutch C2 shown in the drawings are each a multi-plate clutch having a plurality of friction plates, the number of clutch friction plates is not limited by the present invention.

Claims

1. A two-speed drive bridge system without power interruption comprises an electric machine (E), a gear set, a first clutch (C1), a second clutch (C2) and a differential (D),

the gear set comprises a double planetary gear set (PG) comprising 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 being in mesh with the second planet gear (G2), the first planet gear (G1) being in mesh with the first ring gear (R1), the second planet gear (G2) being in mesh with the second ring gear (R2), the first planet gear (G1) and the second planet gear (G2) being non-rotatably juxtaposed in the axial direction (a) of the electric machine (E); wherein the content of the first and second substances,

the outer hub of the first clutch (C1) is fixed, and the inner hub of the first clutch (C1) is connected with the first ring gear (R1) in a non-rotatable way; the outer hub of the second clutch (C2) is fixed, and the inner hub of the second clutch (C2) is connected with the second ring gear (R2) in a non-rotatable way;

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 the outer hub of the first clutch (C1) are in an engaged state and the inner hub and the outer hub of the second clutch (C2) are in a disengaged state, the bridge drive system is in one gear; when the inner and outer hubs of the first clutch (C1) are in a disengaged state and the inner and outer hubs of the second clutch (C2) are in an engaged state, the bridge drive system is in another gear.

2. The bridge drive system according to claim 1, wherein the gear set further comprises a spur gear set including a first spur gear (SG1) and a second spur gear (SG2) that are meshed with each other,

said first spur gear (SG1) being disposed with the same axis of rotation as said sun gear, said second spur gear (SG2) being disposed with the same axis of rotation as the output half-shafts of said differential (D),

the first spur gear (SG1) is connected to the planet carrier in a rotationally fixed manner, and the second spur gear (SG2) is connected to a differential housing of the differential (D) in a rotationally fixed manner.

3. The bridge drive system according to claim 1, further comprising a motor shaft (S1) and a gearbox input shaft (S2),

the rotor of the electric motor (E) is connected in a rotationally fixed manner to the motor shaft (S1), the sun gear is connected in a rotationally fixed manner to the gearbox input shaft (S2),

the motor shaft (S1) and the gearbox input shaft (S2) are integrally formed as the same main shaft.

4. The bridge drive system according to claim 3, wherein both ends of the main shaft in the axial direction (A) are supported by a first bearing (B1) and a third bearing (B3), respectively, and the middle of the main shaft in the axial direction (A) is also supported by a second bearing (B2), the second bearing (B2) being located between the motor (E) and the gear set in the axial direction (A).

5. Bridge drive system according to claim 4, wherein in the axial direction (A) the third bearing (B3) at least partially coincides with the first planet wheel (G1); or

In the axial direction (A), the second bearing (B2) at least partially coincides with the first planet wheel (G1).

6. Bridge drive system according to claim 1, wherein, in the axial direction (A),

the first clutch (C1) is at least partially coincident with the first ring gear (R1), and/or

The second clutch (C2) is at least partially coincident with the second ring gear (R2).

7. Bridge drive system according to claim 1, wherein in a radial direction (R) of the electric machine (E),

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

The diameter of the electric machine (E) is larger than the diameter of the second clutch (C2).

8. The 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.

9. Bridge drive system according to claim 1, in which the diameter of the second planet (G2) is greater than the diameter of the first planet (G1).

10. Bridge drive system according to claim 2, wherein the differential (D) is located radially (R) outside the motor (E), the output half-shaft of the differential (D) being arranged parallel to the motor shaft (S1) of the motor (E).