CN111688479A

CN111688479A - Electric bridge driving system and vehicle

Info

Publication number: CN111688479A
Application number: CN201910184397.7A
Authority: CN
Inventors: 刘磊; 李佳皓
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2019-03-12
Filing date: 2019-03-12
Publication date: 2020-09-22

Abstract

The invention relates to a bridge drive system and a vehicle comprising an electric motor (104, 204) and a gear transmission comprising a first planetary gear mechanism (111, 211), a second planetary gear mechanism (110, 210) and a differential (107, 207), wherein the bridge drive system comprises a motor-side housing (102, 202), a differential-side housing (108, 208) and a middle housing (105, 205) isolating the electric motor (104, 204) and the gear transmission, and further comprising a support member (106, 206) between the first planetary gear mechanism (111, 211) and the second planetary gear mechanism (110, 210), the support member (106, 206) being connected with the middle housing (105, 205) and the differential-side housing (108, 208), respectively, wherein the first planet carrier is rotatably supported at the support member (106, 206) the above.

Description

Electric bridge driving system and vehicle

Technical Field

The invention relates to the technical field of vehicles. More particularly, the present invention relates to a bridge drive system. The invention also relates to a vehicle comprising the electric bridge driving system.

Background

The electric bridge driving system can be used for pure electric vehicles and hybrid electric vehicles. A single speed bridge drive system arranged coaxially is shown for example in chinese patent application CN 102616134A. The bridge driving system comprises a motor, two groups of planetary gear mechanisms and a bevel gear differential mechanism, wherein a motor shaft of the motor, the two groups of planetary gear mechanisms and two half shafts of the differential mechanism are coaxially arranged; the motor shaft is a hollow shaft, and a longer half shaft extends in the hollow shaft; the sun gear of the first planetary gear mechanism is connected to the motor shaft; the sun gear of the second planetary gear mechanism is connected to the carrier of the first planetary gear mechanism; the planet carrier of the second planetary gear set is integrated with the differential housing of the bevel gear differential.

However, in the above-described design, the outer races of both the first planetary gear mechanism and the second planetary gear mechanism are fixed to the transmission case. The differential housing is supported on the transmission housing and the motor shaft. The motor shaft supports both sets of planetary gear mechanism and differential housing, and thus must be designed to be long, which results in poor bearing rigidity of the motor shaft, which is detrimental to noise, vibration and harshness (NVH) of the control system. In addition, since the carrier of the second planetary gear mechanism is supported on the motor shaft by a bearing, so that the axial dimension of the carrier is large, particularly at the position where the second planetary gear mechanism is mounted, the connecting structure of the differential case and the second carrier has poor support rigidity, thus being disadvantageous to the bridge drive system NVH. Furthermore, more bearings are required in this design in order to axially and radially support the planet carrier of the first planetary gear, which increases the costs.

Disclosure of Invention

The technical problem underlying the present invention is therefore to overcome the drawbacks of the prior art and to provide a bridge drive system based on the prior art, which has good performance in terms of noise, vibrations and irregularities.

The object is achieved by a bridge drive system comprising a motor and a gear assembly, the gear assembly comprising a first planetary gear, a second planetary gear and a differential, wherein a motor shaft of the motor, the first planetary gear, the second planetary gear and two half shafts of the differential are arranged coaxially, wherein the motor shaft is a hollow shaft and one half shaft of the differential is arranged within the motor shaft, wherein the first planetary gear comprises a first planet carrier, a first sun gear connected to the motor shaft and a fixedly arranged first ring gear, wherein the second planetary gear comprises a second sun gear connected to the first planet carrier, a second planet carrier connected to a housing of the differential and a fixedly arranged second ring gear. According to the present invention, the bridge drive system includes a motor-side housing, a differential-side housing, and an intermediate housing that isolates the motor and the gear transmission, and further includes a support member that is located between the first planetary gear mechanism and the second planetary gear mechanism, the support member being connected to the intermediate housing and the differential-side housing, respectively, wherein the first carrier is rotatably supported on the support member.

That is, the housing of the bridge drive system according to the present invention includes at least four parts, i.e., a motor-side housing, a middle housing, a differential-side housing, and a support member. The four sections are interconnected to enclose and support the bridge drive system. The four parts are preferably connected by detachable connections, for example by bolts. The motor side housing surrounds at least an axial end face of the motor, the differential side housing surrounds at least an end face of the bridge drive system away from the motor, the intermediate housing isolates the motor from the gear transmission, for example, lubricant on the gear transmission side can be prevented from flowing into the motor, and simultaneously, the support member connected with the intermediate housing and the differential housing is arranged between the axial directions of the two sets of single-row planetary gear mechanisms, so that the first planet carrier and the second sun gear are stably supported, the support stability is better, and the control of NVH is facilitated. Through the supporting scheme, the motor shaft and the second planet carrier can be prevented from being designed to be too large in the axial direction, and NVH can be controlled conveniently.

In a preferred embodiment, the second planet carrier is rotatably supported on the support member. That is, the carrier members simultaneously support the carriers of the two sets of planetary gear mechanisms, so that the carriers of the two sets of planetary gear mechanisms are directly supported on the housing, the support stability is better, and the NVH control is also facilitated.

Advantageously, the support member has a support structure. The first planet carrier and/or the second planet carrier can be supported on the support structure, for example, by bearings. The support structure is for example an axial projection or a hole.

In a further preferred embodiment, the first planet carrier is also rotatably supported on the intermediate housing. The first carrier is thus supported on both the intermediate housing and the support member, making the support of the first planetary gear mechanism more smooth.

In an advantageous embodiment, the first ring gear is fixed to the intermediate housing. Alternatively, the first ring gear is fixed to the support member. Thereby stably supporting the first planetary gear mechanism.

In a further advantageous embodiment, the second ring gear is fixed to the differential-side housing. Alternatively, the second ring gear is fixed to the support member. Thereby stably supporting the second planetary gear mechanism.

In a further advantageous embodiment, the outer circumferential surface of the electric machine is surrounded by a machine-side housing or by an intermediate housing. So that various shell combination schemes can be provided according to design requirements.

The above technical problem is also solved by a vehicle comprising the above bridge drive system.

Drawings

Preferred embodiments of the present invention are schematically illustrated in the following with reference to the accompanying drawings. The attached drawings are as follows:

FIG. 1 is a schematic diagram of a bridge drive system according to a first preferred embodiment of the present invention, an

Fig. 2 is a schematic diagram of a bridge drive system according to a second preferred embodiment of the present invention.

Detailed Description

Fig. 1 shows a schematic diagram of a bridge driving system according to a first preferred embodiment of the present invention. The bridge drive system comprises an electric motor 104 and a gear transmission comprising a first planetary gear mechanism 111, a second planetary gear mechanism 110 and a differential 107. As shown, the motor shaft 103 of the motor 104, the first planetary gear mechanism 111, the second planetary gear mechanism 110, and the two

half shafts

101, 109 of the differential are coaxially arranged. The motor shaft 103 is a hollow shaft and the longer half shaft 101 of the differential 107 is disposed within the motor shaft 103. The first planetary gear set 111 includes a first planet carrier, a first ring gear, and a first sun gear connected to the motor shaft 103, wherein the first sun gear is disposed on the motor shaft 103 by a spline or is integrally manufactured with the motor shaft 103, for example. The second planetary gear mechanism 110 comprises a second ring gear, a second sun gear connected to the first planet carrier, a second planet carrier connected to the housing of the differential 104, wherein the first planet carrier and the second sun gear can be produced in one piece. Thus, in the present embodiment, the power transmission path of the motor is: motor shaft 103 → first sun gear → first carrier → second sun gear → second carrier → differential case → differential side gear →

differential half shafts

101, 109.

In the present embodiment, the bridge drive system includes a motor-side housing 102, a differential-side housing 108, and an intermediate housing 105 that isolate the motor 104 and the gear transmission from each other by bolts. The motor 104 and the first planetary gear mechanism 111 are surrounded on the radial outside by an axial extension of the intermediate housing 105, wherein the first ring gear is fixed to the intermediate housing 105. The motor-side housing 102 is designed as a disc-shaped member, and is connected with the intermediate housing 105 by bolts to surround the motor 104. The differential-side housing 108 encloses the differential and the second planetary gear mechanism 110, wherein the second ring gear is fixed to the differential housing 108. A disc-shaped support member 106 is provided between the first planetary gear mechanism 111 and the second planetary gear mechanism 110, the support member 106 having a center through hole through which the half shaft 101 passes. The support member 106 is bolted to the intermediate case 105 and the differential-side case 108. The first carrier is rotatably supported on the axial projections of the support member 106 and the axial projections of the intermediate housing 105 through bearings. The second carrier is connected to the differential case on one axial side and is supported on the axial projection of the support member via a bearing on the other axial side. Therefore, the two groups of planetary gear mechanisms are respectively supported on the shell of the bridge driving system, the supporting performance is better, and NVH control is facilitated. In addition, such an embodiment facilitates integrating the motor shaft 103 with the first sun gear and integrating the first planet carrier with the second sun gear, which facilitates reducing costs.

Fig. 2 is a schematic diagram of a bridge drive system according to a second preferred embodiment of the present invention. The bridge drive system, like the embodiment shown in fig. 1, includes an electric motor 204 and a gear assembly including a first planetary gear mechanism 211, a second planetary gear mechanism 210, and a differential 207. The gear transmission power transmission path is also the same as in the embodiment shown in fig. 1, i.e., motor shaft 203 → first sun gear → first carrier → second sun gear → second carrier → differential case → differential side gear →

differential half shafts

201, 209.

However, in the present embodiment, the bridge drive system includes a motor-side housing 202, a differential-side housing 208, and an intermediate housing 205 that isolates the motor 204 and the gear transmission from each other by bolts. The radially outer side of the motor 204 is surrounded by an axial extension of the intermediate housing 205. The motor-side housing 202 is designed as a disc-shaped member, and is connected with the intermediate housing 205 by bolts to surround the motor 204. Differential side housing 208 surrounds the differential. Between the first planetary gear mechanism 211 and the second planetary gear mechanism 210, a support member 206 is provided, and the support member 206 includes a disk-shaped section extending in the radial direction and an axial section extending in both axial directions as shown in the drawing. The support member 206 has a central through hole at the disk section through which the half shaft 201 passes. The support member 206 is bolted at both ends of the axial section to the intermediate case 205 and the differential-side case 208. The first ring gear is fixed to the support member 206. The second ring gear is also fixed to the support member 206. The first carrier is rotatably supported on the axial projections of the support member 206 and the axial projections of the intermediate housing 205 through bearings. The second carrier is connected to the differential case on one axial side and is supported on the other axial side by bearings on axial projections of the support member 206. Therefore, the two groups of

planetary gear mechanisms

211 and 210 are respectively supported on the shell of the bridge drive system, so that the supporting performance of the gear transmission device is better, and NVH control is facilitated.

Although possible embodiments have been described by way of example in the above description, it should be understood that numerous embodiment variations exist, still by way of combination of all technical features and embodiments that are known and that are obvious to a person skilled in the art. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. From the foregoing description, one of ordinary skill in the art will more particularly provide a technical guide to convert at least one exemplary embodiment, wherein various changes may be made, particularly in matters of function and structure of the components described, without departing from the scope of the following claims.

List of reference numerals

101 half shaft

102 motor side casing

103 motor shaft

104 electric machine

105 middle shell

106 support member

107 differential

108 differential side housing

109 half shaft

110 second planetary gear mechanism

111 first planetary gear mechanism

201 half shaft

202 motor side shell

203 electric motor shaft

204 motor

205 middle shell

206 support member

207 differential mechanism

208 differential side housing

209 half shaft

210 second planetary gear mechanism

211 first planetary gear mechanism

Claims

1. An electric bridge drive system comprising an electric motor (104, 204) and a gear transmission comprising a first planetary gear mechanism (111, 211), a second planetary gear mechanism (110, 210) and a differential (107, 207),

wherein a motor shaft (103, 203) of the motor (104, 204), the first planetary gear mechanism (111, 211), the second planetary gear mechanism (110, 210), and two half shafts (101, 109, 201, 209) of the differential are coaxially arranged,

wherein the motor shaft (103, 203) is a hollow shaft, one half shaft (101, 201) of the differential (107, 207) being arranged in the motor shaft (103, 203),

wherein the first planetary gear mechanism (111, 211) comprises a first planet carrier, a first sun gear connected to the motor shaft (103, 203) and a fixedly arranged first ring gear,

wherein the second planetary gear mechanism (110, 210) comprises a second sun gear connected with the first planet carrier, a second planet carrier connected with a housing of the differential (107, 207) and a fixedly arranged second ring gear,

it is characterized in that the preparation method is characterized in that,

the bridge drive system includes a motor side housing (102, 202), a differential side housing (108, 208), and an intermediate housing (105, 205) that isolates the motor (104, 204) from the gear assembly,

the bridge drive system further comprises a support member (106, 206) between the first planetary gear mechanism (111, 211) and the second planetary gear mechanism (110, 210), the support member (106, 206) being connected with the intermediate housing (105, 205) and the differential-side housing (108, 208), respectively, wherein the first carrier is rotatably supported on the support member (106, 206).

2. The bridge drive system according to claim 1, wherein the second planet carrier is rotatably supported on the support member (106, 206).

3. Bridge drive system according to claim 1 or 2, wherein the support member (106, 206) has a support structure.

4. The bridge drive system according to claim 1, wherein the first carrier is further rotatably supported on the intermediate housing (105, 205).

5. Bridge drive system according to claim 1, wherein the first ring gear is fixed to the intermediate housing (105).

6. The bridge drive system according to claim 1, wherein the first ring gear is fixed to the support member (206).

7. The bridge drive system according to claim 1, wherein the second ring gear is fixed to the differential-side housing (108).

8. The bridge drive system according to claim 1, wherein the second ring gear is fixed to the support member (206).

9. The bridge drive system according to claim 1, wherein the outer circumferential surface of the motor is surrounded by the motor-side housing or by the intermediate housing (105, 205).

10. A vehicle comprising the bridge drive system according to any one of claims 1 to 9.