Motor shaft structure

Abstract

The utility model relates to the technical field of electric driving systems, in particular to a motor shaft structure which comprises a motor shaft (1). One end of the motor shaft (1) is connected with a motor rear end cover (3); the other end of the motor shaft (1) is connected with a speed reducer input shaft (2); the speed reducer input shaft (2) is connected with a speed reducer; the reducer input shaft and the motor shaft are of an integrated structure. The integration level of the electric drive assembly structure is high, the internal structure is more compact, the arrangement space of the electric drive assembly is saved, and meanwhile the machining difficulty of the shell is effectively reduced; according to the reducer input shaft and the motor shaft, a connecting spline is omitted, the spline machining cost is reduced, the influence of spline fretting wear on the cleanliness and the NVH risk are eliminated, and the reliability and NVH performance of an assembly are improved.

Description

Technical Field

[0001] This utility model relates to the field of electric drive system technology, and more specifically, to a motor shaft structure. Background Technology

[0002] Currently, the reducer input shaft and motor shaft of electric drive assemblies on the market are usually two independent components connected by splines. Therefore, each of the reducer input shaft and motor shaft uses two bearings for support. Some electric drive assemblies combine two adjacent bearings of the motor shaft and reducer input shaft, i.e., use a three-bearing structure. Because of the large number of bearings and their arrangement on different housings, it is necessary to ensure the coaxiality of the bearing holes after assembly, which increases the difficulty of housing machining. At the same time, since the reducer and motor shaft are connected by splines, as the motor speed increases, the cleanliness problems and NVH (Noise, Vibration, and Harshness) problems caused by the fretting wear of the splines gradually become prominent.

[0003] The applicant discovered through a search that Chinese patent document with publication number 113187884A, published on July 30, 2021, discloses a lubrication structure for a motor shaft and a reducer shaft, and a vehicle thereof. The device includes a motor shaft with external splines and a hollow reducer shaft with a shaft hole. The motor shaft extends into the shaft hole of the reducer shaft and engages with the reducer shaft splines. The shaft hole includes a first section and a second section that are interconnected. The inner wall of the first section has an internal spline that corresponds to the external spline on the motor shaft. The axial cross-section of the second section is tapered. The large end of the second section connects to the first section, and the small end connects to an oil guide assembly on the reducer. This device also fails to solve the aforementioned technical problem.

[0004] Therefore, in order to improve or solve at least one of the above problems, it is necessary to provide a motor shaft structure that reduces the machining difficulty of the housing and avoids cleanliness and NVH problems caused by spline wear. Utility Model Content

[0005] The purpose of this invention is to provide a motor shaft structure that reduces the processing difficulty of the housing and avoids cleanliness and NVH problems caused by spline wear.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a motor shaft structure, including a motor shaft; one end of the motor shaft is connected to a motor rear end cover; the other end of the motor shaft is connected to a reducer input shaft; and a reducer is connected to the reducer input shaft.

[0007] The motor rear end cover is provided with a mounting hole; the end of the motor shaft is located in the mounting hole.

[0008] The motor shaft has a first shoulder at its end; a first shaft section is provided on one side of the first shoulder; a first bearing and a retaining ring groove are respectively provided on the first shaft section; a retaining ring is provided in the retaining ring groove; the first bearing is located between the first shoulder and the retaining ring.

[0009] The motor rear end cover is provided with a bearing pressure plate; the bearing pressure plate is located on one side of the first bearing; the bearing pressure plate is provided with a pressure plate fixing bolt; the pressure plate fixing bolt is connected to the motor rear end cover.

[0010] The input shaft of the reducer is provided with a second shoulder at its end; a second shaft section is provided on one side of the second shoulder; a second bearing is provided on the second shaft section; the second bearing abuts against the second shoulder.

[0011] The second bearing is connected to the motor housing; a gap is provided between the second bearing and the motor housing.

[0012] The input shaft of the reducer is provided with gear teeth; the gear teeth are located on one side of the second bearing.

[0013] Both the motor shaft and the reducer input shaft are provided with axial oil holes; the motor shaft is provided with radial oil holes; the axial oil holes and the radial oil holes are connected.

[0014] The input shaft of the reducer is provided with a third shoulder at the end near the motor shaft; the radial oil hole includes a first radial oil hole and a second radial oil hole; the first radial oil hole is located on one side of the third shoulder; the second radial oil hole is located on one side of the first shoulder.

[0015] The beneficial effects of this application are as follows:

[0016] 1. The reducer input shaft and motor shaft of this application are integrated into one structure; this makes the electric drive assembly structure highly integrated, the internal structure more compact, saves the electric drive assembly layout space, and effectively reduces the processing difficulty of the housing.

[0017] 2. The reducer input shaft and motor shaft of this application eliminate the connecting spline, which reduces the spline processing cost, eliminates the impact of spline fretting wear on cleanliness and NVH risk, and improves the reliability and NVH performance of the assembly.

[0018] 3. The reducer input shaft and motor shaft of this application are integrated, eliminating NVH problems caused by misalignment between the motor shaft and the reducer input shaft; this application uses two bearings for support, reducing the number of bearings used and the number of bearing holes machined in the housing, thus reducing the overall assembly cost; at the same time, the reducer input shaft oil seal is eliminated, improving system efficiency; this application dissipates heat from the rotor and stator windings by slinging oil through the inner hole of the motor shaft; the motor shaft and reducer input shaft of this application are integrated, and a bearing pressure plate is installed on one side of the first bearing and fixed to the rear end cover of the motor by a retaining ring, eliminating the need for a wave spring. Attached Figure Description

[0019] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, wherein:

[0020] Figure 1 This is a schematic diagram of the motor shaft structure.

[0021] The markings in the above figures are all:

[0022] The diagram is marked as follows:

[0023] 1. Motor shaft,

[0024] 2. Reducer input shaft,

[0025] 3. Motor rear end cover, 301. Mounting hole, 302. Bearing pressure plate, 303. Pressure plate fixing bolts.

[0026] 4. First shoulder; 401. First shaft section; 402. First bearing; 403. Snap ring groove; 404. Snap ring.

[0027] 5. Second shoulder, 501. Second shaft section, 502. Second bearing.

[0028] 6. Gear teeth,

[0029] 7. Axial oil hole; 701. Radial oil hole; 702. First radial oil hole; 703. Second radial oil hole.

[0030] 8. Third shoulder. Detailed Implementation

[0031] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of this utility model, and to facilitate its implementation.

[0032] Figure 1 The motor shaft structure shown includes a motor shaft 1; one end of the motor shaft 1 is connected to a motor rear end cover 3; the other end of the motor shaft 1 is connected to a reducer input shaft 2; and the reducer input shaft 2 is connected to a reducer.

[0033] The reducer input shaft 2 and motor shaft 1 of this application are integrated into one structure, which makes the electric drive assembly structure highly integrated, the internal structure more compact, saves the layout space of the electric drive assembly, and effectively reduces the processing difficulty of the housing. The reducer input shaft 2 and motor shaft 1 of this application eliminate the connecting spline, which reduces the spline processing cost, eliminates the impact of spline fretting wear on cleanliness and NVH risk, and improves the reliability and NVH performance of the assembly.

[0034] The motor rear end cover 3 is provided with a mounting hole 301; the end of the motor shaft 1 is located in the mounting hole 301.

[0035] One end of the motor shaft 1 is inserted into the mounting hole 301 and can rotate flexibly in the mounting hole 301; thus, the end of the motor shaft 1 can be movably connected to the rear end cover 3 of the motor.

[0036] The end of the motor shaft 1 is provided with a first shoulder 4; a first shaft section 401 is provided on one side of the first shoulder 4; a first bearing 402 and a retaining ring groove 403 are respectively provided on the first shaft section 401; a retaining ring 404 is provided in the retaining ring groove 403; the first bearing 402 is located between the first shoulder 4 and the retaining ring 404.

[0037] The first shoulder 4 and the motor shaft 1 are an integral structure; the first shaft section 401 is located at the end of the motor shaft 1 near the rear end cover 3 of the motor; the diameter of the first shaft section 401 is smaller than that of the motor shaft 1; the first shaft section 401 is installed in the mounting hole 301 through the first bearing 402; the retaining ring 404 is engaged in the retaining ring groove 403; the first shoulder 4 and the retaining ring 404 limit the first bearing 402, which can effectively prevent the first bearing 402 from moving axially; the first shaft section 401 is provided with a fixing component, which can be the retaining ring 404, or a locking nut or other parts that play a fixing role, and the fixing component limits the bearing axially.

[0038] The motor rear end cover 3 is provided with a bearing pressure plate 302; the bearing pressure plate 302 is located on one side of the first bearing 402; the bearing pressure plate 302 is provided with a pressure plate fixing bolt 303; the pressure plate fixing bolt 303 is connected to the motor rear end cover 3.

[0039] The bearing pressure plate 302 is fixedly connected to the rear end cover 3 of the motor by the pressure plate fixing bolt 303; the bearing pressure plate 302 is located at the top of the mounting hole 301, and the bottom of the bearing pressure plate 302 extends downward, thereby limiting the first bearing 402 and effectively preventing the first bearing 402 from moving axially.

[0040] The end of the input shaft 2 of the reducer is provided with a second shoulder 5; a second shaft section 501 is provided on one side of the second shoulder 5; a second bearing 502 is provided on the second shaft section 501; the second bearing 502 abuts against the second shoulder 5.

[0041] The second shoulder 5 and the reducer input shaft 2 are an integral structure; the second shaft section 501 is located at the end of the reducer input shaft 2 away from the motor shaft 1; the second shaft section 501 is mounted on the motor housing through the second bearing 502, thereby enabling the reducer input shaft 2 to be supported and rotated flexibly; this application uses two bearings, the first bearing 402 and the second bearing 502, for support. Compared with the traditional three-bearing or four-bearing support structure, at least one bearing is eliminated, thereby reducing costs. At the same time, the machining of the bearing hole on the motor housing is eliminated, reducing machining costs. In addition, the two-bearing support reduces the coaxiality requirement of the bearing hole in the housing compared with the three-bearing or four-bearing support, reduces the difficulty of machining, and is also conducive to improving NVH performance.

[0042] The second bearing 502 is connected to the motor housing; a gap is provided between the second bearing 502 and the motor housing.

[0043] The second bearing 502 has an axial clearance with the motor housing, which allows the motor shaft 1 and the reducer input shaft 2 to have a certain amount of axial expansion and contraction space; the axial clearance adjustment of the reducer input shaft 2 is eliminated (the adjusting shim is eliminated), and since one end of the motor shaft 1 is fixed, the wave spring is also eliminated, which reduces costs while ensuring performance.

[0044] The input shaft 2 of the reducer is provided with gear teeth 6; gear teeth 6 are located on one side of the second bearing 502.

[0045] Gear teeth 6 are machined on the side wall of the reducer input shaft 2 near the second bearing 502. Motor windings are installed on the motor shaft 1. The motor shaft 1 and the reducer input shaft 2 are an integral structure. The motor shaft 1 and the reducer input shaft 2 rotate together. The gear teeth 6 are connected to the reducer, thereby transmitting power to the reducer and ultimately driving the vehicle. The gear teeth 6 can be integrated with the reducer input shaft 2, or the gear can be installed on the reducer input shaft 2 through a spline or other connection structure, which is beneficial to improving NVH performance. The gear teeth 6 can be located between the second bearing 502 and the third shaft shoulder 8, or the gear teeth 6 can be located on the side of the second bearing 502 away from the third shaft shoulder 8.

[0046] Both the motor shaft 1 and the reducer input shaft 2 are provided with axial oil holes 7; the motor shaft 1 is provided with radial oil holes 701; the axial oil holes 7 and the radial oil holes 701 are connected.

[0047] When lubricating oil enters the axial oil hole 7, due to the rotation of the motor shaft 1 and the reducer input shaft 2, the lubricating oil is thrown out through the radial oil hole 701, which can cool the motor shaft 1 and the motor windings. This device is provided with axial oil hole 7 and radial oil hole 701, but it is also possible not to provide axial oil hole 7 and radial oil hole 701.

[0048] The input shaft 2 of the reducer is provided with a third shoulder 8 at the end near the motor shaft 1; the radial oil hole 701 includes a first radial oil hole 702 and a second radial oil hole 703; the first radial oil hole 702 is located on one side of the third shoulder 8; the second radial oil hole 703 is located on one side of the first shoulder 4.

[0049] The motor winding is mounted on the motor shaft 1 and located between the third shaft shoulder 8 and the rear end cover 3 of the motor; the axial oil hole 7 is located inside the motor shaft 1 and the input shaft 2 of the reducer; when the motor shaft 1 rotates, the lubricating oil in the axial oil hole 7 is thrown out from the first radial oil hole 702 and the second radial oil hole 703, thereby cooling the motor shaft 1 and the motor winding.

[0050] This device can be used on both oil-cooled and water-cooled motors.

[0051] The specific workflow of this utility model is as follows:

[0052] This device integrates the motor shaft 1 and the reducer input shaft 2 directly into one unit. Gear teeth 6 are machined at one end of the reducer input shaft 2 to transmit the motor power to the reducer. A first shaft section 401 and a second shaft section 501 are respectively provided at the ends of the motor shaft 1 and the reducer input shaft 2 to install the first bearing 402 and the second bearing 502. The two bearings serve as supports for the motor shaft 1 and the reducer input shaft 2. An axial oil hole 7 and a radial oil hole 701 are provided inside the motor shaft 1 and the reducer input shaft 2. When lubricating oil enters the axial oil hole 7, due to the rotation of the motor shaft 1, the lubricating oil is thrown out through the radial oil hole 701, thereby cooling the motor shaft 1 and the motor windings.

[0053] A retaining ring groove 403 is provided on the first shaft section 401. After the first bearing 402 is assembled, a retaining ring 404 is installed for axial positioning. At the same time, after the motor shaft assembly is assembled into the rear end cover 3 of the motor, the first bearing 402 is pressed tightly using the bearing pressure plate 302 and the pressure plate fixing bolts 303. The second bearing 502 has an axial gap with the motor housing.

[0054] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A motor shaft structure, characterized in that: It includes a motor shaft (1); one end of the motor shaft (1) is connected to a motor rear end cover (3); the other end of the motor shaft (1) is connected to a reducer input shaft (2); the reducer input shaft (2) is connected to a reducer.

2. The motor shaft structure according to claim 1, characterized in that: The motor rear end cover (3) is provided with a mounting hole (301); the end of the motor shaft (1) is located in the mounting hole (301).

3. A motor shaft structure according to claim 2, characterized in that: The motor shaft (1) has a first shoulder (4) at its end; a first shaft section (401) is provided on one side of the first shoulder (4); a first bearing (402) and a retaining ring groove (403) are provided on the first shaft section (401); a retaining ring (404) is provided in the retaining ring groove (403); the first bearing (402) is located between the first shoulder (4) and the retaining ring (404).

4. A motor shaft structure according to claim 3, characterized in that: The motor rear end cover (3) is provided with a bearing pressure plate (302); the bearing pressure plate (302) is located on one side of the first bearing (402); the bearing pressure plate (302) is provided with a pressure plate fixing bolt (303); the pressure plate fixing bolt (303) is connected to the motor rear end cover (3).

5. A motor shaft structure according to any one of claims 3-4, characterized in that: The input shaft (2) of the reducer is provided with a second shoulder (5) at its end; a second shaft section (501) is provided on one side of the second shoulder (5); a second bearing (502) is provided on the second shaft section (501); the second bearing (502) abuts against the second shoulder (5).

6. A motor shaft structure according to claim 5, characterized in that: The second bearing (502) is connected to the motor housing; a gap is provided between the second bearing (502) and the motor housing.

7. A motor shaft structure according to claim 6, characterized in that: The input shaft (2) of the reducer is provided with gear teeth (6); the gear teeth (6) are located on one side of the second bearing (502).

8. A motor shaft structure according to any one of claims 6-7, characterized in that: Both the motor shaft (1) and the reducer input shaft (2) are provided with axial oil holes (7); the motor shaft (1) is provided with radial oil holes (701); the axial oil holes (7) and the radial oil holes (701) are connected.

9. A motor shaft structure according to claim 8, characterized in that: The input shaft (2) of the reducer is provided with a third shoulder (8) at the end near the motor shaft (1); the radial oil hole (701) includes a first radial oil hole (702) and a second radial oil hole (703); the first radial oil hole (702) is located on one side of the third shoulder (8); the second radial oil hole (703) is located on one side of the first shoulder (4).

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