CN115071414A

CN115071414A - Speed reducer and electric automobile

Info

Publication number: CN115071414A
Application number: CN202210757589.4A
Authority: CN
Inventors: 蒋付强; 柯枫
Original assignee: Weilai Power Technology Hefei Co Ltd
Current assignee: Weilai Power Technology Hefei Co Ltd
Priority date: 2022-06-30
Filing date: 2022-06-30
Publication date: 2022-09-20

Abstract

The application discloses reduction gear and electric automobile including it. The speed reducer includes a first speed reducing mechanism including a first gear connected with a motor and a plurality of second gears each meshing with the first gear on a radially inner side thereof; a differential connected to a pair of wheels; and a second reduction mechanism connected between the first reduction mechanism and the differential; wherein the first reduction mechanism further comprises a chain with which each of the plurality of second gears is meshed on a radially outer side thereof. The present application provides a compact arrangement of the speed reducer.

Description

Speed reducer and electric automobile

Technical Field

The application relates to the field of automobiles, in particular to a speed reducer.

The application also relates to an electric vehicle comprising the speed reducer.

Background

With the guidance and advocated of national policies on energy conservation and emission reduction, new energy automobiles are rapidly developing. As an important component of the development of new energy vehicles, high-speed miniaturization, light weight and silence have become a main research direction. An electric drive system for a new energy vehicle usually comprises three major parts, namely a motor, a controller and a speed reducer, wherein the speed reducer is used as an important component, and the design form of the speed reducer is crucial to the electric drive system. At present, the mainstream speed reducer is of a single-gear parallel shaft structure, and the speed reducer with a partial offset coaxial structure and a planetary gear coaxial structure is developed and used. The speed reducers of the parallel shaft structure and the offset coaxial structure have higher requirements on the longitudinal space on the arrangement of the whole vehicle, and the higher the rotating speed and the larger the torque of the electric drive system are, the larger the structural sizes of the two speed reducers are. The traditional reducer with the planet wheel coaxial structure is small in transmission ratio and obvious in NVH problem, and meanwhile, the problems of high manufacturing cost, high assembly difficulty and the like of parts exist.

Disclosure of Invention

One aspect to which the present application relates is to provide a reducer having a more optimized constructive design than comparable reducers of the prior art.

A decelerator, comprising: a first reduction mechanism including a first gear set including a first gear and a plurality of second gears, wherein the first gear is connected with the motor, and the plurality of second gears are each meshed with the first gear on a radially inner side thereof; a differential connected to a pair of wheels; and a second reduction mechanism connected between the first reduction mechanism and the differential; wherein the first reduction mechanism further includes a chain, each of the plurality of second gears being meshed with the chain on a radially outer side thereof.

Wherein, in one embodiment of the reducer, the plurality of second gears is three and is arranged evenly around the first gear.

Wherein, in one embodiment of the speed reducer, the second speed reducing mechanism includes a plurality of third gears and a fourth gear, each of the plurality of third gears being meshed with the fourth gear on a radially outer side thereof.

Wherein, in one embodiment of the speed reducer, the differential is integrated on the second reduction mechanism.

In one embodiment of the speed reducer, the speed reducer further includes a plurality of intermediate shafts, each of the second gears is supported on a corresponding one of the intermediate shafts, each of the intermediate shafts further supports the third gear, and the case of the differential is connected to one end of each of the intermediate shafts.

In one embodiment of the reducer, each of the intermediate shafts comprises concentric outer and inner shafts, the outer shaft being arranged for rotation relative to the inner shaft, and the housing of the differential being fixed to the inner shaft.

Wherein, in one embodiment of the reducer, the fourth gear is an inner gear ring, and the inner gear ring is configured to be fixed in the reduction gearbox.

In one embodiment of the reduction gear, one of the axle shafts of the differential for connecting the wheels is arranged to pass through the output shaft of the electric machine.

The present application relates to a reducer having two-stage reduction and having a simplified and easily implemented configuration. The speed reducer has a chain transmission type speed reducing mechanism of a first stage, and the radial size of the speed reducing mechanism of the first stage can be reduced by using a chain, and the NVH performance of the speed reducer is improved. In addition, the use of a chain reduces the need for a central moment between the first gear and each second gear. The present application also relates to a reduction gear having a second reduction coaxial to the chain-driven reduction and integrated with a differential, having further reduced radial and axial dimensions, so as to obtain a reduction gear assembly of optimized dimensions. And a larger torque can be transmitted between the first-stage speed reducing mechanism and the second-stage speed reducing mechanism through a plurality of intermediate shafts under the condition of the same speed reducing ratio than that of a single intermediate shaft.

Another aspect of the present application is to provide an electric vehicle including the speed reducer in any one of the above embodiments.

Wherein, in an embodiment of the electric vehicle, the retarder is arranged to be connected to front and/or rear wheels of the electric vehicle.

The application relates to a whole volume of reduction gear and weight reduction, NVH performance is better and transmission efficiency is higher, therefore the electric automobile who has this reduction gear has corresponding advantage and good whole car performance.

Other aspects and features of the present application will become apparent from the following detailed description, which proceeds with reference to the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the application, for which reference should be made to the appended claims. It should be further understood that the drawings are merely intended to conceptually illustrate the structures and procedures described herein, and that, unless otherwise indicated, the drawings are not necessarily drawn to scale.

Drawings

The present application will be more fully understood from the detailed description given below with reference to the accompanying drawings, in which like reference numerals refer to like elements throughout the views. Wherein:

FIG. 1 is a schematic layout of an embodiment of a retarder to which the present application relates; and

fig. 2 shows a power transmission route of the reduction gear in fig. 1.

Detailed Description

To assist those skilled in the art in understanding the subject matter claimed herein, specific embodiments thereof are described below in detail with reference to the accompanying drawings.

Fig. 1 shows a schematic layout of a speed reducer to which the present application relates. Referring to fig. 1, a motor 1 is provided as a power source. The reduction gear includes a first reduction mechanism 20 and a second reduction mechanism 30 having two gear ratios, and a differential 8. The differential 8 is connected to a pair of

wheels

13, 14. On the power transmission route, the motor 1 is connected to the first reduction mechanism 20, and the second reduction mechanism 30 is located between the first reduction mechanism 20 and the differential 8.

The first reduction mechanism 20 includes a gear train having a first gear 2 and a plurality of second gears 3. The first gear 2 is connected to an output shaft 11 of the motor 1, and the first gear 2 and each of the second gears 3 are meshed on a radially inner side thereof. The first reduction mechanism 20 further includes a chain 4. The chains 4 are arranged to mesh with the respective second gear 3 on the radially outer side thereof.

Further, the second gear 3 is preferably more than three, and still more preferably three, arranged at equal intervals on the periphery of the first gear 2. In order to illustrate the chain assembly, fig. 1 shows the first gear 2 meshing with two second gears, respectively, it being understood that in the embodiment with three second gears, if the first gear is sectioned centrally, the first gear 2 can be seen in section and in meshing engagement with one of the second gears 3, the other two being invisible. The chain 4 meshes with each of the second gears to enclose them.

The chain transmission is utilized to meet the requirement on the center distance, the requirement is not required to be accurate like gear transmission, and meanwhile, the performance of the chain is insensitive to the heat effect and the manufacturing tolerance, so that the assembly is relatively simple, a larger reduction ratio can be provided under the same center distance, or the center distance can be reduced under the same reduction ratio, the miniaturization and the light weight of the reducer assembly are realized, and the electric drive system is more friendly in the arrangement space of the whole vehicle. In addition, chain drive structure can show the holistic noise level of reduction gear that reduces, can improve its NVH performance when improving reduction gear efficiency by a wide margin.

Through the arrangement mode, the problems that the conventional speed reducer has high requirement on the longitudinal space of the whole vehicle, the structural size is increased along with the increase of torque and rotating speed, the transmission ratio is small, the NVH problem is obvious, the manufacturing cost of parts is high, and the assembly difficulty is high can be solved.

The second reduction mechanism 30 also has a gear train including a plurality of third gears 6 and a fourth gear 7. A plurality of third gears 6 mesh with a fourth gear 7 on the radially outer side. The fourth gear 7 is an inner gear ring and is fixed in the shell of the reduction gearbox. Therefore, when the third gear 6 is meshed with the fourth gear 7, the third gear 6 can rotate as a planetary gear with respect to the ring gear.

The plurality of third gears 6 and the plurality of second gears 3 of the first reduction mechanism are coaxial so that the number of third gears 6 corresponds to the number of second gears 3. In the embodiment in which the reduction gear has three second gear wheels 3, there are correspondingly three third gear wheels 6, each second gear wheel 3 and each third gear wheel 6 being supported jointly on an intermediate shaft 5. The three intermediate shafts 5 are evenly arranged around the output shaft 11 of the motor 1 to achieve transmission of power from the first reduction mechanism 20 to the second reduction mechanism 30.

The differential 8 may be integrated into the second reduction mechanism 30 in the following manner. The intermediate shaft 5 comprises concentric outer and

inner shafts

51, 52. The outer shaft 51 is used to support the second gear 3 and the third gear 6. The end of the inner shaft 52 remote from the second gearwheel 3 is fixed to the housing 81 of the differential 8. Further, the inner shaft 52 is supported by the outer shaft 51 through a bearing. When the plurality of third gears 6 rotate relative to the ring gear, the housing 81 of the differential 8 can be driven to rotate together. The integration of the differential is not limited to the above arrangement, and may be achieved in other conceivable ways, including but not limited to, that one end of the intermediate shaft remote from the second gear is connected to the housing of the differential through a bearing, so that the third gear and the intermediate shaft input power to the differential while rotating relative to the ring gear, and the rotation of the intermediate shaft is independent.

Further, the differential 8 comprises two half-

shafts

91, 92, one of which 91 passes inside the output shaft 11 of the electric machine to be connected to one side of the wheels 13, as shown in the figure, i.e. the output shaft 11 of the electric machine 1 is provided as a hollow shaft. The other half-shaft 92 is connected to the other side of the wheel 14. The axle shaft 91 may be supported in the output shaft 11 by bearings.

The present application provides a compact arrangement of the speed reducer. The first-stage speed reducing mechanism replaces the traditional gear transmission through chain transmission, the size of a driven gear in the first-stage speed reducing mechanism is reduced, the requirement for the center distance in manufacturing is lowered, and the overall NVH performance of the speed reducer can be improved through the chain transmission. The differential is integrated with the second-stage reduction mechanism, so that the axial size can be reduced. The first-stage speed reducing mechanism and the second-stage speed reducing mechanism are coaxially connected, and power is transmitted through a plurality of intermediate shafts, so that the transmission efficiency can be improved.

Fig. 2 shows a power transmission route of the reduction gear in fig. 1, wherein the power transmission route is indicated by an arrow. The motor 1 drives a first gear that transmits power to the first reduction mechanism. Three second gears 3 are meshed with the first gear 2, and three intermediate shafts 5 are evenly distributed on the outside thereof around the axis of the output shaft 11 of the motor 1. Meanwhile, the three second gears 3 are meshed and connected through the same chain 4, and primary speed reduction is achieved jointly. Further, the three intermediate shafts 5 transmit power to the second speed reducing mechanism. The three third gears 6 rotate relative to the fourth gear 7, i.e. the ring gear, thereby rotating the housing 81 of the differential 8. The three third gears 6 as driven gears are engaged with the ring gear as a driving gear, thereby realizing two-stage speed reduction. The

half shafts

91, 92 in the differential 8 transfer power to the

wheels

13, 14 on both sides, respectively.

The electric automobile that this application still relates to includes the reduction gear of aforesaid. The retarder may be connected to the front and/or rear wheels.

While specific embodiments of the present application have been shown and described in detail to illustrate the principles of the application, it will be understood that the application may be embodied otherwise without departing from such principles.

Claims

1. A speed reducer is characterized by comprising:

a first reduction mechanism (20), the first reduction mechanism (20) including a first gear (2) and a plurality of second gears (3), wherein the first gear (2) is connected with a motor (1), and the plurality of second gears (3) are each meshed with the first gear (2) on a radially inner side thereof;

a differential (8) connected to a pair of wheels; and

a second reduction mechanism (30) connected between the first reduction mechanism (20) and the differential (8);

wherein the first reduction mechanism (20) further comprises a chain (4), each of the plurality of second gears (3) being engaged with the chain (4) on a radially outer side thereof.

2. A decelerator according to claim 1 wherein: the plurality of second toothed wheels (3) is three and is arranged uniformly around the first toothed wheel (2).

3. A decelerator according to claim 1 wherein: the second reduction mechanism (30) includes a plurality of third gears (6) and a fourth gear (7), and the plurality of third gears (6) are each meshed with the fourth gear (7) on a radially outer side thereof.

4. A decelerator according to claim 3 wherein: the differential (8) is integrated with the second reduction mechanism (30).

5. A decelerator according to claim 3 or 4 wherein: and a plurality of intermediate shafts (5), wherein the plurality of second gears (3) are supported on one of the intermediate shafts (5) corresponding to the second gears, each intermediate shaft (5) further supports the third gear (6), and a shell (81) of the differential (8) is connected with one end of each intermediate shaft (5).

6. A decelerator according to claim 5 wherein: each intermediate shaft (5) comprises an outer shaft (51) and an inner shaft (52) which are concentric, the outer shaft (51) being arranged to rotate relative to the inner shaft (52), and the housing (81) of the differential (8) being fixed with the inner shaft (52).

7. A decelerator according to claim 3 or 4 wherein: the fourth gear (7) is an inner gear ring, and the inner gear ring is fixed in the reduction gearbox.

8. A decelerator according to claim 3 or 4 wherein: one of the half shafts of the differential (8) for connecting the wheels is arranged to pass through the output shaft (11) of the electric machine (1).

9. An electric vehicle characterized by comprising a decelerator according to any one of claims 1-8.

10. An electric vehicle according to claim 9, wherein the retarder is arranged to be connected to a front wheel and/or a rear wheel of the electric vehicle.