Supporting structure for reducing degree of freedom of electromechanical transmission output shaft and output gear

Abstract

The invention discloses a supporting structure for reducing the degree of freedom of an electromechanical transmission output shaft and an output gear, which belongs to the technical field of mechanical design and comprises a cylindrical pin, the output shaft, a flange plate, the output gear and a bearing. The flange plate is mounted on the box body; the flange plate is supported on the output gear through a bearing; one end of the output shaft is coaxially sleeved in an axial blind hole A in the output gear; the output gear and the output shaft are coaxially connected through a cylindrical pin; one end of the cylindrical pin is in transition fit with an axial blind hole B in the output gear, and the other end of the cylindrical pin is in transition fit with an axial blind hole C in the output shaft. According to the invention, the cylindrical pin is utilized to restrain the redundant degrees of freedom of the output gear and the output shaft in the axial direction and the radial direction, and the coaxiality between the output shaft and the output gear is improved, so that the assembly error is reduced, the dynamic load is reduced, and the overall performance and reliability of an electromechanical transmission system are improved.

Description

Technical Field

[0001] The invention belongs to the field of mechanical design, and in particular relates to a support structure for reducing the freedom of an electromechanical transmission output shaft and an output gear, and is a reliable structure that can be widely used in reducing the freedom of output gears and improving stability. Background Art

[0002] In the vehicle system, the output gear or output mechanism is used to smoothly output the torque and speed of the transmission mechanism to the side drive, and then output it to the driving wheel from the side drive. Therefore, the stability of the output gear affects the performance of the entire transmission system and even the performance of the vehicle. In the transmission system, the stability of the output gear is closely related to its own degree of freedom and the degree of coincidence with the axis centerline of the output shaft. In the vehicle electromechanical transmission system, the power starts from the power source (motor), passes through the reduction gear and the coupling gear to the speed gear (arranged symmetrically on both sides from the inside to the outside), and is finally transmitted to the output gear through the output shaft. In this process, the output gear is supported on the housing by bearings to ensure its stable operation.

[0003] like Figure 1 As shown, in the prior art, the output gear 7 and the output shaft 2 are axially fixed in the following manner: a key is used between the output gear 7 and the output shaft 2, and the output gear 7 is pressed on the output shaft 2 by a locking nut 9 to achieve axial fixation. For further stability, a retaining ring is installed at each of the front and rear ends of the output gear 7 to prevent the locking nut 9 from loosening. The output gear 7 is supported inside the housing by a bearing, and a retaining ring is provided on the bearing to prevent the bearing from axial movement.

[0004] Due to the limited space inside the box, the matching length between the output shaft 2 and the output gear 7 is reduced, which easily causes the end of the output shaft 2 to be misaligned with the output gear 7 in its radial direction (perpendicular to the axis), and the gap between the output shaft 2 and the output gear 7 further increases the possibility of up and down swinging. This swinging will cause relative movement between the output gear 7 and the output shaft 2, making it impossible to align the axis centerline of the output gear 7 and the axis centerline of the output shaft 2, thereby increasing the assembly error. At the same time, since there is inevitably a certain gap in the axial direction of the bearing, the output gear or output shaft may move left and right in the axial direction, further increasing the assembly error. The assembly error increases the dynamic load of the output gear 7 and the output shaft 2, and ultimately reduces the performance of the electromechanical transmission system and the entire vehicle.

[0005] In order to solve this problem, a support structure needs to be designed to ensure the axial fixation between the output gear and the output shaft, thereby overcoming the above challenges. This support structure should be able to effectively reduce or eliminate axial and radial movement and swing, ensure accurate alignment of the gear and shaft, reduce assembly errors, and reduce dynamic loads, so as to improve the overall performance and reliability of the electromechanical transmission system. Summary of the invention

[0006] In view of this, the present invention provides a support structure for reducing the freedom of the output shaft and output gear of the electromechanical transmission, and utilizes cylindrical pins to constrain the redundant axial and radial freedom (axial movement and radial swing) of the output gear and the output shaft, thereby improving the coaxiality between the output shaft and the output gear, thereby reducing assembly errors, reducing dynamic loads, and further improving the overall performance and reliability of the electromechanical transmission system.

[0007] The present invention is achieved through the following technical solutions:

[0008] A support structure for reducing the freedom of an output shaft and an output gear of an electromechanical transmission, comprising: a cylindrical pin, an output shaft, a flange, an output gear and a bearing;

[0009] The flange is installed on the box body;

[0010] The flange is supported on the output gear through a bearing;

[0011] One end of the output shaft is coaxially sleeved in the axial blind hole A in the output gear;

[0012] The output gear and the output shaft are coaxially connected through the cylindrical pin; one end of the cylindrical pin is transitionally matched with the axial blind hole B on the output gear, and the other end of the cylindrical pin is transitionally matched with the axial blind hole C on the output shaft.

[0013] Furthermore, the output shaft and the output gear are key-fitted.

[0014] Furthermore, one end of the output gear is machined with a sleeve shaft along its axial direction;

[0015] The sleeve shaft of the output gear is supported on the housing through a bearing; the axial blind hole A is machined on the sleeve shaft, and the axial blind hole B is machined on the inner bottom surface of the axial blind hole A;

[0016] The axial blind hole C is machined on the end surface of the output shaft sleeved in the blind hole A.

[0017] Furthermore, the axial distance between the end surface of one end of the cylindrical pin and the inner bottom surface of the axial blind hole B is 2 to 3 mm.

[0018] Furthermore, the bottom of the axial blind hole A, the bottom of the axial blind hole B, the bottom of the axial blind hole C, the end of the cylindrical pin and the end of the output shaft are all chamfered.

[0019] Further, it also includes: an axial gasket and two snap rings;

[0020] The two retaining rings are arranged on one end surface of the bearing, and the axial gasket is arranged on the other end surface of the bearing, thereby realizing axial limitation of the bearing.

[0021] Beneficial effects:

[0022] (1) The present invention provides a support structure for reducing the freedom of an output shaft and an output gear of an electromechanical transmission. The two ends of a cylindrical pin are coaxially connected to the output gear and the output shaft, respectively, so that the output gear and the output shaft can overlap. One end of the cylindrical pin and the output gear, and the other end of the cylindrical pin and the output shaft are transitionally matched, so that the relative movement between the output gear and the output shaft can be prevented, so that the output gear and the output shaft can rotate concentrically. At the same time, a rotation constraint pair is provided for the floating output shaft in the axial direction (i.e., the output shaft is prevented from swinging during rotation), so that the output shaft and the output gear can rotate more accurately on the rotation axis of the support bearing, thereby improving the coaxiality between the output shaft, the output gear and the bearing. At the same time, the output gear is restrained from swinging up and down in the radial direction, and the output gear is reduced from moving left and right in the axial direction, so that the output gear can run smoothly in one direction of the rotation working freedom, thereby improving the centering accuracy, and reducing the dynamic load caused by unstable factors such as the relative movement between the output shaft and the output gear, thereby improving the performance of the electromechanical transmission and the whole vehicle, and better adapting to the requirements of high speed and heavy load.

[0023] (2) The present invention provides a support structure for reducing the freedom of the output shaft and output gear of an electromechanical transmission. The output shaft and the output gear are key-matched, which can avoid stress concentration and further ensure the centering accuracy between the output gear and the output shaft.

[0024] (3) In the support structure for reducing the freedom of the output shaft and output gear of the electromechanical transmission of the present invention, the axial clearance between the end face of one end of the cylindrical pin and the inner bottom surface of the axial blind hole B is 2 to 3 mm, which can avoid assembly interference between the output shaft, the cylindrical pin and the output gear in the axial direction.

[0025] (4) The present invention provides a support structure for reducing the freedom of an electromechanical transmission output shaft and an output gear, wherein the bottom of the axial blind hole A, the bottom of the axial blind hole B, the bottom of the axial blind hole C, the end of the cylindrical pin and the end of the output shaft are all chamfered, so that the support structure is easy to install.

[0026] (5) The present invention provides a support structure for reducing the freedom of the electromechanical transmission output shaft and the output gear. Two retaining rings are arranged on one end face of the bearing, and an axial gasket is arranged on the other end face of the bearing. The gear can be axially limited and the axial movement of the output gear and the output shaft can be further limited. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a supporting structure in the prior art;

[0028] Figure 2 is a cross-sectional view of the present invention;

[0029] Among them, 1-cylindrical pin, 2-output shaft, 3-spline, 4-circlip A, 5-circlip B, 6-flange, 7-output gear, 8-bearing, 9-locking nut, 10-front circlip, 11-rear circlip, 12-axial gasket. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0031] This embodiment provides a support structure for reducing the freedom of the electromechanical transmission output shaft and output gear, such as Figure 2 As shown, it includes: a cylindrical pin 1, an output shaft 2, a spline 3, a flange 6, an output gear 7, a bearing 8, an axial gasket 12 and two retaining rings.

[0032] The flange 6 is installed on the box body and fixed by bolts.

[0033] One end of the output gear 7 is processed with a sleeve shaft along its axial direction (that is, one end has a cylindrical protrusion extending axially). The flange 6 is supported on the sleeve shaft of the output gear 7 through the bearing 8. An axial blind hole A is processed on the sleeve shaft of the output gear 7. A spline 3 is processed on the inner wall surface of the axial blind hole A, that is, the spline 3 is an internal spline. An axial blind hole B with a diameter smaller than the diameter of the axial blind hole A is processed on the inner bottom surface of the axial blind hole A. The bottom of the axial blind hole B is chamfered. In this embodiment, the diameter of the axial blind hole B is about 20 mm, the depth of the axial blind hole B is about 10 mm, and the taper of the chamfer is 60°. The axial blind hole B is coated with lubricating oil to reduce the friction resistance during the assembly process to facilitate the installation of the output shaft 2. In this embodiment, the roughness of the inner circumferential surface of the axial blind hole B is less than or equal to 0.8.

[0034] The output shaft 2 is coaxially sleeved in the axial blind hole A of the output gear 7. The end face of the output shaft 2 sleeved in the blind hole A is processed with an axial blind hole C. The bottom of the axial blind hole C and the end of the output shaft 2 are chamfered. In this embodiment, the diameter of the axial blind hole C is about 20 mm, the axial depth is about 20 mm, and the taper of the chamfer is 60°. The outer wall surface of the output shaft 2 is processed with a spline, that is, the spline is an external spline. The external spline on the output shaft 2 cooperates with the internal spline of the output gear 7 to realize the spline connection between the output shaft 2 and the output gear 7. The axial blind hole A, the axial blind hole B and the axial blind hole C are coaxial. In this embodiment, the roughness of the inner circumferential surface of the axial blind hole C is less than or equal to 0.8.

[0035] One end of the cylindrical pin 1 is coaxially sleeved in the axial blind hole B of the output gear 7, and the other end of the cylindrical pin 1 is coaxially sleeved in the axial blind hole C of the output shaft 2. The two ends of the cylindrical pin 1 are transitionally matched with the axial blind hole B and the axial blind hole C respectively. The tolerance range between the outer diameter of the cylindrical pin 1 and the diameter of the axial blind hole B, and the outer diameter of the cylindrical pin 1 and the diameter of the axial blind hole C is within ±0.0015mm. The ends of the cylindrical pin 1 are chamfered so that the two ends of the cylindrical pin 1 can be easily pressed into the axial blind hole B and the axial blind hole C during assembly. The axial spacing between one end of the cylindrical pin 1 and the inner bottom surface of the axial blind hole B of the output gear 7 is 2 to 3 mm, which is used to avoid assembly interference between the output shaft 2, the cylindrical pin 1 and the output gear 7 in the axial direction. The other end face of the cylindrical pin 1 is against the inner bottom surface of the axial blind hole C. In this embodiment, the roughness of the outer circumferential surface of the cylindrical pin 1 is less than or equal to 0.8, and this roughness is beneficial to the matching accuracy between the cylindrical pin 1 and the output shaft 2, and between the cylindrical pin 1 and the output gear 7.

[0036] Two snap rings are arranged on one end face of the bearing 8. The two snap rings are snap ring A4 and snap ring B5. Snap ring B5 is arranged between the outer ring of the bearing 8 and the flange 6 (located inside the flange 6) and is an inner snap ring. Snap ring A4 is arranged between the inner ring of the bearing 8 and the sleeve shaft of the output gear 7 (located outside the sleeve shaft of the output gear 7) and is an outer snap ring. Snap ring A4 and snap ring B5 are used for axial limit of this end of the bearing 8.

[0037] The axial gasket is arranged on the other end face of the bearing 8 and is used for axially limiting the end of the bearing 8.

[0038] In this embodiment, the coaxiality of the axial blind hole A, the axial blind hole B and the axial blind hole C needs to reach a sufficiently high accuracy (accuracy within ±0.001, i.e., within 2 lines).

[0039] The steps for installing the support structure are as follows:

[0040] The first step is to assemble the output gear 7, two retaining rings, flange 6, bearing 8, bearing gasket and oil seal together.

[0041] In the second step, insert the cylindrical pin 1 into the axial blind hole C of the output shaft 2.

[0042] In the third step, the output shaft 2 is assembled into the axial blind hole A of the output gear 7 through the spline 3. At this time, one end of the cylindrical pin 1 is pushed into the axial blind hole B along with the output shaft 2. Since the other end of the output shaft 2 is processed with a chamfered cone surface, it can be easily pressed in after the external spline is aligned with the internal spline.

[0043] The fourth step is to securely connect the flange 6 to the box body to complete the assembly.

[0044] Working principle:

[0045] In this embodiment, the output gear 7 and the output shaft 2 are connected by a cylindrical pin 1. The transition fit between the output gear 7 and the cylindrical pin 1, and the transition fit between the output shaft 2 and the cylindrical pin 1, can suppress the redundant degrees of freedom of the output shaft 2, avoid the relative movement (including axial movement and radial swing) between the output gear 7 and the output shaft 2, thereby ensuring that the axis of the output gear 7 and the output shaft 2 coincide or nearly coincide, and can achieve the output shaft 2 to run smoothly in one rotational degree of freedom direction, thereby reducing the coaxiality error.

[0046] The connected output gear 7 and output shaft 2 are supported by bearings 8 and a power source, thereby improving the stability and durability of the entire output mechanism.

[0047] Since the cylindrical pin 1 is located inside the output gear 7 and the output shaft 2, the occupied space can be reduced, the stability and durability of the output mechanism in a small space can be achieved, and the dynamic load caused by unstable connection is reduced, thereby improving the performance of the electromechanical transmission and the entire vehicle.

[0048] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A support structure for reducing the freedom of an electromechanical transmission output shaft and an output gear, characterized in that: include: Cylindrical pin (1), output shaft (2), flange (6), output gear (7) and bearing (8); The flange (6) is mounted on the box body; The flange (6) is supported on the output gear (7) via a bearing (8); One end of the output shaft (2) is coaxially sleeved in an axial blind hole A in the output gear (7); The output gear (7) and the output shaft (2) are coaxially connected via the cylindrical pin (1); one end of the cylindrical pin (1) is transitionally matched with the axial blind hole B on the output gear (7), and the other end of the cylindrical pin (1) is transitionally matched with the axial blind hole C on the output shaft (2).

2. A support structure for reducing the degree of freedom of an electromechanical transmission output shaft and an output gear as claimed in claim 1, characterized in that: The output shaft (2) and the output gear (7) are key-matched.

3. A support structure for reducing the degree of freedom of an electromechanical transmission output shaft and an output gear as claimed in claim 1 or 2, characterized in that: One end of the output gear (7) is machined with a sleeve shaft along its axial direction; The sleeve shaft of the output gear (7) is supported on the housing through a bearing (8); the axial blind hole A is machined on the sleeve shaft, and the axial blind hole B is machined on the inner bottom surface of the axial blind hole A; The axial blind hole C is machined on the end surface of the output shaft (2) which is sleeved in the blind hole A.

4. A support structure for reducing the degree of freedom of an electromechanical transmission output shaft and an output gear as claimed in claim 3, characterized in that: The axial distance between the end surface of one end of the cylindrical pin (1) and the inner bottom surface of the axial blind hole B is 2 to 3 mm.

5. A support structure for reducing the degree of freedom of an electromechanical transmission output shaft and an output gear as claimed in claim 3, characterized in that: The bottom of the axial blind hole A, the bottom of the axial blind hole B, the bottom of the axial blind hole C, the end of the cylindrical pin (1) and the end of the output shaft (2) are all chamfered.

6. A support structure for reducing the degree of freedom of an electromechanical transmission output shaft and an output gear as claimed in claim 1, characterized in that: Also included: an axial spacer and two retaining rings; The two retaining rings are arranged on one end surface of the bearing (8), and the axial gasket is arranged on the other end surface of the bearing (8), thereby achieving axial limiting of the bearing (8).

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