Differential with reverse drum-shaped shaft hole, vehicle gearbox and vehicle electric driving system
By designing an inverted drum-shaped shaft hole, the wear problem of the differential under vibration or torque imbalance was solved, achieving higher durability and reliability.
Patent Information
- Application Number
- CN202520461610.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2035-03-14
AI Technical Summary
The shaft bore and half shaft of the existing differential are prone to wear when there is vibration or torque imbalance, especially when the concentricity is not high, which leads to welding failure.
The shaft hole adopts an inverted drum-shaped design, with the shaft hole being an arc or parabola in any axial section. The shaft hole protrudes radially inward at the middle position of the axial direction, ensuring that the half shaft can maintain clearance or slight contact when tilted or bent, thus reducing wear.
It effectively reduces wear between the shaft hole and the half shaft, improves the durability and reliability of the differential, and reduces the failure rate.
Smart Images
Figure CN223768055U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of differential technology, and particularly to a differential with an inverted drum-shaped shaft hole, a vehicle transmission, and a vehicle electric drive system. Background Technology
[0002] The vehicle's electric drive system has a differential. Figure 1 A differential 10 known to the inventor is shown. The differential 10 has a housing 11 and two side gears 12. The housing 11 has two shaft holes 11A and 11B, into which a half shaft 20 (or drive shaft) can be inserted for transmission connection with the side gears 12 of the differential.
[0003] Figure 1 In the differential 10 shown, the shaft holes 11A and 11B are cylindrical holes.
[0004] Figure 2A and Figure 2B The diagram schematically illustrates the state in which the half-shaft 20 is inserted into a shaft hole 11A. See also... Figure 2A When the half-shaft 20 is not tilted or bent, that is, when the central axis of the half-shaft 20 coincides with the central axis AX of the differential 10, the gap between the half-shaft 20 and the shaft hole 11A is uniform and there is no obvious wear problem.
[0005] The half-shaft 20 is relatively long, and it may tilt or bend under vibration or torque imbalance. In this case, see [link to relevant documentation]. Figure 2B The half shaft 20 will come into contact with the edge of the shaft hole 11A, causing wear or failure. Figure 2B The diagram schematically shows the right end of the half-shaft 20 (the outer end of the differential 10 in the axial direction) tilting upwards. At position X1 (outer edge) on the upper right side and position X2 (inner edge) on the lower left side of the shaft hole 11A, the half-shaft 20 is in contact with the hole 11A, which can easily lead to wear or welding failure.
[0006] At the same time, when the concentricity between the half shaft and the differential housing is not high, the half shaft will also tilt and press against the edge of the shaft hole, resulting in wear and welding failures. Utility Model Content
[0007] This application is made in view of the aforementioned state of the prior art. The purpose of this application is to provide a differential, a vehicle transmission, and a vehicle electric drive system having an inverted drum-shaped shaft bore.
[0008] A differential with an inverted drum-shaped shaft bore is provided, comprising a housing and two side gears housed within the housing, characterized in that the housing includes two shaft bores located on opposite axial sides of the two side gears, and a half-shaft is capable of being inserted into the shaft bores for transmission connection with the side gears.
[0009] The shaft hole is inverted drum shape. In any axial section of the housing, the inner surface of the shaft hole is an arc or parabola, and the axial middle position of the shaft hole protrudes radially inward toward the housing.
[0010] Optionally, in any axial section of the housing, the inner surface of the shaft hole is axisymmetric about the central axis of the housing.
[0011] Optionally, in any axial section of the housing, the two inner surfaces of the shaft hole form a hyperbola.
[0012] Optionally, the housing includes a housing body and two shaft support portions extending from the housing body toward both axial sides, the inner peripheral surface of the shaft support portion defining the shaft hole, and the outer peripheral surface of the shaft support portion being fitted with a bearing.
[0013] Optionally, the minimum diameter of the shaft hole is 0.7 to 2.0 times the axial length of the shaft hole.
[0014] Optionally, the side gear has an internal spline for connection with the half-shaft spline, and the minimum radius of the shaft hole is equal to or greater than the radius at the root of the internal spline.
[0015] Optionally, the differential further includes a differential pin and a plurality of planetary gears mounted to the differential pin, the side gears meshing with the planetary gears.
[0016] Optionally, the differential further includes an input gear, and the housing comprises two symmetrical half-shells, which are respectively welded to the axial sides of the input gear.
[0017] Embodiments of this application also provide a vehicle transmission including a differential with an inverted drum-shaped shaft bore according to this application.
[0018] Embodiments of this application also provide a vehicle electric drive system, which includes a motor, a transmission mechanism, a differential with an inverted drum-shaped shaft bore according to this application, and two half-shafts.
[0019] The motor drives the differential via the speed change mechanism. The two half-shafts are respectively inserted into the two shaft holes of the differential housing and are connected to the side gear of the differential.
[0020] The differential according to the embodiments of this application can reduce wear between the shaft hole and the half shaft, especially when, for example, the half shaft and the housing of the differential are not highly concentric, and the half shaft tilts or bends due to vibration or torque imbalance, thus reducing the force and wear between the shaft hole and the half shaft. Attached Figure Description
[0021] Figure 1A cross-sectional view of a differential known to the inventor is shown.
[0022] Figure 2A and Figure 2B The diagram schematically illustrates the insertion of the half-shaft into... Figure 1 The state of one shaft hole of the differential, wherein, Figure 2B The half-axis is tilted.
[0023] Figure 3 A cross-sectional view of a differential according to one embodiment of this application is shown.
[0024] Figure 4A and Figure 4B The diagram schematically illustrates the insertion of the half-shaft into... Figure 3 The state of one shaft hole of the differential, wherein, Figure 4B The half-axis is tilted. Detailed Implementation
[0025] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.
[0026] In this application, "transmission connection" refers to a connection between two components that can transmit torque, including direct or indirect connection between the two components.
[0027] See Figures 3 to 4B One embodiment of this application provides a differential 100 with an inverted drum-shaped shaft bore. The differential 100 may include a housing 110 and two side gears (also referred to as sun gears) 120 housed within the housing 110. The housing 110 includes two shaft bores 110A and 110B located on both axial sides of the two side gears 120, and a half-shaft 200 can be inserted into the shaft bores 110A and 110B for transmission connection with the side gears 120. Figure 4A and Figure 4B The diagram schematically shows the insertion of the half-shaft 200 into... Figure 3 The state of one shaft hole 110A of the differential in the gearbox.
[0028] Here, the shaft holes 110A and 110B are inverted drum shape. In any axial section of the housing 110 (i.e., the section passing through the central axis AX of the housing 110), the inner surfaces of the shaft holes 110A and 110B are arcs or parabolas. The axial middle position of the shaft holes 110A and 110B protrudes radially inward toward the housing 110.
[0029] Optionally, in any axial section of the housing 110, the inner surfaces of the shaft holes 110A and 110B are symmetrical about the central axis AX of the housing 110.
[0030] In a non-limiting example, in any axial section of the housing 110, the two inner surfaces of the shaft holes 110A and 110B form a hyperbola.
[0031] See Figure 4A When the half-shaft 200 is not tilted or bent, that is, when the central axis of the half-shaft 200 coincides with the central axis AX of the differential 10, there is a gap between the half-shaft 200 and the shaft hole 110A, and there is no obvious wear problem. It can be understood that here, one end of the half-shaft 200 ( Figure 4A The left end of the differential 100 (the inner end on axial direction A) is inserted into the shaft hole 110A and is connected to a side gear 120 for transmission. The other end of the half shaft 200 ( Figure 4A The right end of the differential 100 (the outer end on the axial direction A) can be connected to a wheel.
[0032] Figure 4B The diagram schematically illustrates the upward tilt of the right end of the half-shaft 200 (the outer end on the axial direction A of the differential 100). The points of proximity or contact between the half-shaft 200 and the shaft hole 110A are point X10 on the upper right side (outer axial direction) and point X20 on the lower left side (inner axial direction). Since the shaft hole 110A is inverted drum-shaped, the diameters at its two axial ends are larger than the diameter at its axial midpoint. Points X10 and X20 are radially outer than the axial midpoint of the shaft hole (the innermost point on the radial direction R). Therefore, although the half-shaft 200 is tilted, at points X10 and X20, the half-shaft 200 and the shaft hole 110A can maintain a certain clearance or contact without significant clamping force. Thus, in the differential 100 of this embodiment, the half-shaft 200 and the shaft hole 110A can maintain a clearance or contact without significant clamping force in more cases, thereby reducing the likelihood of wear.
[0033] Optionally, the housing 110 may include a housing body 110M and two shaft support portions 110S extending axially from the housing body 110M to both sides. The inner peripheral surface of the shaft support portion 110S defines shaft holes 110A and 110B, and the outer peripheral surface of the shaft support portion 110S may be fitted with a bearing 130.
[0034] Optionally, the minimum diameter R1 of the shaft holes 110A and 110B can be 0.7 to 2.0 times the axial length A1 of the shaft holes 110A and 110B. This allows the shaft holes 110A and 110B to have sufficient length to support the stable operation of the half-shaft 200. Simultaneously, the outer circumferential surface of the shaft support portion 110S has sufficient space to install the bearing 130. The inverted drum shape of this embodiment is particularly advantageous for shaft holes with a certain axial length.
[0035] Optionally, the side gear 120 has an internal spline for spline connection with the half shaft 200. The half shaft 200 may have an external spline, and the minimum radius of the shaft holes 110A and 110B may be equal to or greater than the radius at the root of the internal spline (the tip of the external spline), thus facilitating the insertion of the half shaft 200 into the shaft hole and spline connection with the side gear 120.
[0036] Optionally, the differential 100 also includes a differential pin 140 and a plurality of planetary gears 150 mounted to the differential pin 140, with a side gear 120 meshing with the planetary gears 150. Here, by way of example and not limitation, the differential pin 140 is a slotted pin with two planetary gears 150.
[0037] Optionally, the differential 100 may also include an input gear (or final reduction gear, final drive gear) 160, and the housing 110 may include two symmetrical half-shells 111 and 112, which may be welded to the axial sides of the input gear 160 respectively.
[0038] The two symmetrical half-shells can be manufactured by stamping, for example, from low-carbon steel. After stamping, some parts can be machined. For example, shaft holes 110A and 110B can be formed by machining after stamping. The two symmetrical half-shells can have the same structure, thereby reducing the number of parts and lowering production costs.
[0039] Embodiments of this application also provide a vehicle transmission that may include a differential 100 having a reverse-drum shaped shaft bore according to embodiments of this application. The transmission may further include a shift mechanism.
[0040] Embodiments of this application also provide a vehicle electric drive system, which may include a motor, a transmission mechanism, a differential 100 with an inverted drum-shaped shaft hole according to an embodiment of this application, and two half-shafts 200. The motor drives the differential 100 via the transmission mechanism, and the two half-shafts 200 are respectively inserted into two shaft holes 110A and 110B of the differential housing 110 and are drively connected to the side gear 120 of the differential. In this way, the torque of the motor can be transmitted to the two wheels via the transmission mechanism and the differential 100.
[0041] It is understandable that the half-shaft may or may not be part of the differential.
[0042] It is understood that, in this application, when the number of parts or components is not specifically limited, the number can be one or more, where multiple refers to two or more. For cases where the number of parts or components shown in the drawings and / or described in the specification is, for example, two, three, four, etc., this specific number is generally exemplary and not restrictive, and can be understood as multiple, i.e., two or more; however, this does not mean that this application excludes the case of one.
[0043] It should be understood that the above-described embodiments, examples, or examples are merely exemplary and are not intended to limit this application. Those skilled in the art can make various modifications and changes to the above-described embodiments, examples, or examples under the teachings of this application without departing from the scope of this application.
Claims
1. A differential having a counter-bell shaped axle hole, comprising a housing and two side gears accommodated in the housing, characterized in that, The housing includes two shaft holes on the axial two sides of the two side gears, and a half shaft can be inserted into the shaft hole to be in driving connection with the side gear, The shaft hole is reverse drum-shaped, and in any axial section of the housing, the inner surface of the shaft hole is an arc or a parabola, and the axial middle position of the shaft hole protrudes to the radially inner side of the housing.
2. The differential with counter-bell shaped axle hole of claim 1, wherein, In any axial section of the housing, the inner surface of the shaft hole is axisymmetric about the central axis of the housing.
3. The differential with counter-bell shaped axle hole of claim 1 wherein, In any axial section of the housing, the two inner surfaces of the shaft hole form a hyperbola.
4. The differential with counter-bell shaped axle hole of claim 1 wherein, The housing includes a housing body and two shaft support parts protruding from the housing body towards the axial two sides, the inner circumferential surface of the shaft support part defines the shaft hole, and the outer circumferential surface of the shaft support part is provided with a bearing.
5. The differential with counter-bell shaped axle hole of claim 1 wherein, The minimum diameter of the shaft hole is 0.7 to 2.0 times the axial length of the shaft hole.
6. The differential with counter-bell shaped axle hole of claim 1 wherein, The side gear has an inner spline for connection with a half shaft spline, and the minimum radius of the shaft hole is equal to or greater than the radius at the root of the inner spline.
7. The differential with counter-bell shaped axle hole of claim 1 wherein, The differential further includes a differential pin and a plurality of planetary gears mounted to the differential pin, and the side gear is in mesh with the planetary gears.
8. The differential with counter-bell shaped axle hole of claim 1 wherein, The differential further includes an input gear, and the housing includes two symmetrical half shells, which are respectively welded to the axial two sides of the input gear.
9. A vehicle transmission, characterized by The differential with a reverse drum-shaped shaft hole according to any one of claims 1 to 8.
10. A vehicle electric drive system, characterized by, The motor, the transmission mechanism, the differential with a reverse drum-shaped shaft hole according to any one of claims 1 to 8, and the two half shafts, The motor drives the differential via the transmission mechanism, and the two half shafts are respectively inserted into the two shaft holes of the housing of the differential and are in driving connection with the side gears of the differential.