Gearbox

Abstract

The utility model relates to a gearbox which comprises a shell and a gear transmission pair, the shell is provided with a containing space, a spline groove extending in the axial direction is formed in the inner wall of the shell, the gear transmission pair is arranged in the containing space, and the gear transmission pair comprises a gear ring located on the radial outer side; a wide-tooth spline matched with the spline groove is arranged on the outer wall of the gear ring, and the tooth crest of the wide-tooth spline is embedded into the spline groove. A traditional densely-distributed small spline with a gear ring matched with a shell is changed into a wide-tooth spline structure with a small number and an enlarged size. By increasing the circumferential size of the single spline tooth, the rigidity and strength of the single spline tooth are improved, and meanwhile the structural stability of the whole gear ring is enhanced. The gear ring deformation is effectively reduced, abnormal contact between the gear ring and the shell is reduced, the machining cost of the spline teeth and the spline grooves is reduced, and the NVH performance of the gear box can be better improved.

Description

Technical Field

[0001] This utility model relates to the field of gearbox technology, and in particular to a gearbox. Background Technology

[0002] In a vehicle's transmission system, the gearbox (transmission) is a key transmission component between the engine or drive motor and the wheels. Its core function is to convert the high-speed, low-torque output of the engine or drive motor into a low-speed, high-torque output suitable for wheel drive through multi-stage gear ratio conversion, so that the engine or drive motor always operates in the optimal speed range, achieving a balance between power and fuel economy.

[0003] Currently, traditional gearboxes employ a combination structure of an aluminum alloy housing and a steel alloy gear transmission pair. The gear transmission pair mainly includes a core gear set located in the center, a differential, and a gear ring and retaining ring located on the outer ring. During forward and reverse operation of the gearbox, torque is transmitted through the core gear set and the differential, while the load is transmitted to the gearbox housing through the gear ring.

[0004] like Figures 1 to 3 As shown, in the related technology, the gear ring 21 and the housing 10 adopt a straight tooth-spline groove clearance fit. However, the clearance fit between the gear ring 21 and the housing 10 causes obvious vibration and noise during transmission. Especially in electric vehicle application scenarios, due to the lack of engine noise masking, the vibration and noise problems are particularly prominent.

[0005] In addition, the outer wall of the current gear ring 21 needs to be machined with 50 straight teeth 210, and the inner wall of the corresponding gearbox housing 10 needs to be machined with 50 matching spline grooves 110. This straight tooth-spline groove mating structure has extremely high machining precision, and must be machined using high-precision CNC machine tools. Moreover, the single-piece machining cycle is long, the production efficiency is low, and the cost is high. Utility Model Content

[0006] To overcome the problems existing in the related technologies, this disclosure provides a gearbox.

[0007] According to a first aspect of the present disclosure, a gearbox is provided, comprising: a housing having a receiving space, an axially extending spline groove provided on the inner wall of the housing, and a gear transmission pair disposed within the receiving space, the gear transmission pair including a gear ring located radially outward, the outer wall of the gear ring being provided with a wide-tooth spline that mates with the spline groove, the tooth tip of the wide-tooth spline being embedded in the spline groove.

[0008] In some embodiments, the wide-tooth spline is a trapezoidal spline tooth, and two oblique tooth surfaces are respectively provided on both sides of the circumferential direction of the wide-tooth spline, and the radial outer wall of the wide-tooth spline is an arc-shaped outer wall.

[0009] In some embodiments, the helical tooth surface is provided with a wave groove extending axially along the wide tooth spline.

[0010] In some embodiments, the angle between the helical tooth surface of the wide-tooth spline and the outer wall of the gear ring is 50°-70°.

[0011] In some embodiments, the gear transmission pair further includes a retaining ring, which is sleeved on the outer wall of the gear ring, and the outer wall of the retaining ring forms a radial clearance fit with the inner wall of the housing.

[0012] In some embodiments, at least one or more of the inner wall of the housing, the inner wall of the spline groove, the oblique tooth surface and arcuate outer wall of the wide-tooth spline, and the outer wall of the retaining ring are coated with a damping material layer.

[0013] In some embodiments, the tooth height of the wide-tooth spline is greater than the keyway depth of the spline groove, and there is a radial clearance fit between the tooth tip of the wide-tooth spline and the bottom of the spline groove.

[0014] In some embodiments, the outer wall of the gear ring is uniformly distributed with three wide-tooth splines along the circumferential direction; and the inner wall of the housing is correspondingly provided with three spline grooves along the circumferential direction.

[0015] In some embodiments, the central angle corresponding to the wide tooth spline is in the range of 50°-120°, and the axial width of the wide tooth spline accounts for 30% to 80% of the total axial width of the gear ring.

[0016] In some embodiments, the gear transmission pair further includes a core gear set and a differential, and the ring gear is connected to the radial outer periphery of the core gear set and the differential.

[0017] The technical solutions provided by the embodiments of this disclosure can include the following beneficial effects: replacing the dense, small spline teeth that traditionally mate with the housing in a gear ring with a smaller, larger wide-tooth spline structure. By increasing the circumferential dimension of a single spline tooth, the rigidity and strength of the individual spline tooth are improved, while simultaneously enhancing the overall structural stability of the gear ring. This effectively reduces gear ring deformation and abnormal contact between the gear ring and the housing, not only lowering the processing costs of the spline teeth and spline grooves but also effectively improving and enhancing the NVH (noise, vibration, and harshness) performance of the gearbox. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0019] Figure 1 This is a cross-sectional view of a gearbox in related technologies;

[0020] Figure 2 This is a top view of the fit between the gear ring and the gearbox housing in related technologies;

[0021] Figure 3 This is a side sectional view of the mating of the gear ring and the gearbox housing in related technologies;

[0022] Figure 4 This is a top view of the gearbox connection structure according to an exemplary embodiment;

[0023] Figure 5 This is a side sectional view of a gearbox connection structure according to an exemplary embodiment;

[0024] Figure 6 yes Figure 4 A magnified schematic diagram of a portion of the structure in section F. Detailed Implementation

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0026] In this invention, unless otherwise specified, axial A, radial R, and circumferential W refer to the axial A, radial R, and circumferential W of the gearbox 100, respectively; radial outer refers to the direction radially away from. Figure 4 The upper side of the middle and Figure 5 The right side of the diagram. Additionally, "transmission connection" refers to the ability to transmit driving force / torque between two components, which can be directly connected or achieved through various transmission mechanisms or connection structures. The term "torsional connection" refers to a connection between two elements that does not rotate relative to each other, which can be achieved via a press fit (i.e., interference fit) or by integrally forming the two components. Those skilled in the art will understand the specific meaning of the above terms in this invention as appropriate.

[0027] To solve the above-mentioned technical problems, this disclosure provides a gearbox 100, including a housing 10 and a gear transmission pair 20. For example... Figure 1As shown, the housing 10 has an internal receiving space 11 for accommodating and mounting the gear transmission pair 20. A spline groove 12 is provided on the circumferential inner wall of the housing 10, extending axially along axis A. The gear transmission pair 20 is disposed within the receiving space 11 and includes a core gear set 22, a differential 23, and a gear ring 21 located on the radial outer periphery. The inner wall of the gear ring 21 is connected to the core gear set 22 and the differential 23 via the spline groove 12. The outer wall of the gear ring 21 is provided with a wide-tooth spline 211 that mates with the spline groove 12 of the housing 10. The tooth tips of the wide-tooth spline 211 are embedded in the spline groove 12, achieving circumferential positioning of the gear ring 21 relative to the housing 10.

[0028] In related technologies Figure 2 Compared with the embodiments in this example Figure 4 As can be seen from the comparison, this disclosure replaces the dense, small splines that traditionally mate with the housing 10 on the gear ring 21 with fewer, larger wide-tooth splines 211. The increased circumferential dimension of the wide-tooth splines 211 enhances their load-bearing capacity and reduces local stress concentration. Simultaneously, the larger size of the wide-tooth splines 211 effectively increases the stiffness of the gear ring 21, reduces its deformation, and minimizes abnormal contact between the gear ring 21 and the housing 10, thereby improving the NVH (noise, vibration, and harshness) performance of the gearbox 100. Furthermore, the fewer wide-tooth splines 211 on the outer wall of the gear ring 21 reduce the machining difficulty and cost of the spline teeth and spline grooves 12.

[0029] In some embodiments, the wide-tooth spline 211 can be rectangular teeth. In exemplary embodiments of this disclosure, such as... Figure 3 As shown, the wide tooth spline 211 is a trapezoidal spline tooth. The trapezoidal wide tooth spline 211 has two oblique tooth surfaces 212 on each side of its circumference. The radial outer wall of the wide tooth spline 211 is an arc-shaped outer wall 213.

[0030] The helical tooth surface 212 and the arc-shaped outer wall 213 further increase the contact area between the wide tooth spline 211 and the spline groove 12. Under the same load transmitted by the core gear set 22 and the differential 23 to the gear ring 21, the larger the contact area between the wide tooth spline 211 and the spline groove 12, the smaller the contact pressure and the smaller the deformation of the gear ring 21. This is beneficial to reducing the vibration and noise caused by the collision between the gear ring 21 and the housing 10. Due to the less collision contact and the lower contact pressure, it is also beneficial to extend the service life of the gear ring 21 and the housing 10.

[0031] In some embodiments, the helical tooth surface 212 of the wide-tooth spline 211 can be a plane. In this embodiment, as shown... Figure 6As shown, a wavy groove 214 extending along the axial direction A is machined on the helical tooth surface 212 of the wide-tooth spline 211. This wavy groove 214, with its gently sloping wave structure, not only facilitates manufacturing but also allows for contact between the helical tooth surface 212 of the wide-tooth spline 211 and the inner wall of the spline groove 12, increasing the circumferential torsional resistance between the gear ring 21 and the housing 10 and improving the stability of the circumferential positioning fit between the gear ring 21 and the housing 10. Simultaneously, the curved contact of the wavy groove 214 further increases the contact area between the wide-tooth spline 211 and the spline groove 12, thereby further reducing the pressure on the housing 10 when the gear ring 21 deforms.

[0032] In some embodiments, the trapezoidal wide-tooth spline 211 can adopt an isosceles trapezoidal structure, that is, the lengths of the two helical tooth surfaces 212 of the wide-tooth spline 211 are consistent, and the included angle α between the two helical tooth surfaces 212 and the outer wall of the gear ring 21 is equal. Preferably, the circumferential outer wall of the gear ring 21 is provided with three wide-tooth replacement parts, and the included angle α between the helical tooth surfaces 212 and the outer wall of the gear ring 21 is 50°-70°. The wide-tooth spline 211 structure within this included angle α range is more stable and has good rigidity. Preferably, the included angle α is 60°.

[0033] It should be noted that, depending on the requirements of the different application environments of the gear ring 21, the value of the included angle α can be adjusted according to parameters such as the diameter of the gear ring 21, the thickness of the gear ring 21, and the number of wide tooth splines 211. The specific value needs to be determined according to the actual working conditions.

[0034] In some embodiments, the gear transmission pair 20 further includes a retaining ring 24, which is sleeved on the outer wall of the gear ring 21, and the outer wall of the retaining ring 24 forms a radial clearance fit with the inner wall of the housing 10. The retaining ring 24 is used to fix the gear ring 21, and the retaining ring 24 can constrain the gear ring 21 circumferentially and radially, further limiting excessive deformation of the gear ring 21 and excessive interference with the inner wall of the housing 10.

[0035] In some embodiments, at least one or more of the inner wall of the housing 10, the inner wall of the spline groove 12, the helical tooth surface 212 and arcuate outer wall 213 of the wide tooth spline 211, and the arcuate outer wall 213 of the retaining ring 24 are coated with a damping material layer. The damping material may be a polyurethane elastomer to further absorb the vibration and noise generated by the collision between the gear ring 21 and the housing 10, thereby improving the NVH performance of the gearbox 100.

[0036] In some embodiments, the tooth height of the wide-tooth spline 211 is greater than the keyway depth of the spline groove 12, and a radial clearance fit is formed between the tooth tip of the wide-tooth spline 211 and the bottom of the spline groove 12. Simultaneously, the outer wall of the gear ring 21 and the inner wall of the housing 10 also form a radial clearance fit. The tooth height of the wide-tooth spline 211 refers to the radial distance from the tooth tip to the tooth root. The keyway depth of the spline groove 12 refers to the radial depth from the inner wall of the housing 10 to the bottom of the keyway.

[0037] Within the gearbox 100, the positioning accuracy of the gear transmission pair 20 is ensured by radial positioning of the shaft and bearings. Maintaining the radial clearance fit between the tooth tip of the wide-tooth spline 211 and the bottom of the spline groove 12, as well as the radial clearance fit between the outer wall of the gear ring 21 and the inner wall of the housing 10, ensures smooth assembly and effectively avoids assembly interference problems caused by over-positioning. This improves the assembly efficiency of the components while ensuring positioning accuracy.

[0038] In some embodiments, the outer wall of the gear ring 21 has three wide-tooth splines 211 evenly distributed along the circumferential direction W. Correspondingly, the inner wall of the housing 10 has three spline grooves 12 along the circumferential direction W. This symmetrical arrangement ensures both the stability of circumferential positioning and the uniform distribution of loads or pressures transmitted from the gear ring 21 to the housing 10. In other optional embodiments, the number of wide-tooth splines 211 on the outer wall of the gear ring 21 can be adjusted according to the structural parameters of the gear ring 21 (such as thickness, diameter, etc.) to meet the structural strength and assembly requirements under different working conditions.

[0039] In exemplary embodiments of this disclosure, such as Figure 4 As shown, the central angle of the wide tooth spline 211 ranges from 50° to 120°, and the axial width H1 of the wide tooth spline 211 accounts for 30% to 80% of the total axial width of the gear ring 21.

[0040] like Figure 4 As shown, by setting the central angle of the wide-tooth spline 211 within the range of 50°-120°, the wide-tooth spline 211 can have a larger circumferential width W1. The circumferential width W1 is defined as the straight-line distance between the intersection points of the helical tooth surfaces 212 on both sides of the wide-tooth spline 211 and the outer wall of the gear ring 21. The larger circumferential width W1 provides a larger contact area between the wide-tooth spline 211 and the spline groove 12, enabling the wide-tooth spline 211 to withstand higher circumferential torque and improving the stability and positioning reliability of the gear ring 21.

[0041] like Figure 5 As shown, the axial width H1 of the wide tooth spline 211 accounts for 30% to 80% of the total axial width of the gear ring 21. This ratio range ensures that the fit depth between the wide tooth spline 211 and the spline groove 12 is sufficient, which can effectively limit axial displacement and avoid assembly difficulties caused by interference fit.

[0042] It should be noted that the angle range of the central angle and the axial width H1 of the wide tooth spline 211 mentioned above are parameters obtained by finite element analysis verification in combination with load and other working conditions. The above parameters can be adjusted according to different load requirements, and no specific limitation is made here.

[0043] It is understood that in this disclosure, "multiple" refers to two or more, and other quantifiers are similar. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. The singular forms "a" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0044] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0045] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A gearbox (100), characterized in that, include: The housing (10) has a receiving space (11), and the inner wall of the housing (10) is provided with a spline groove (12) extending axially. A gear transmission pair (20) is disposed in the receiving space (11). The gear transmission pair (20) includes a gear ring (21) located on the radial outer side. The outer wall of the gear ring (21) is provided with a wide-tooth spline (211) that mates with the spline groove (12). The tooth tip of the wide-tooth spline (211) is embedded in the spline groove (12).

2. The gearbox (100) according to claim 1, characterized in that, The wide-tooth spline (211) has trapezoidal spline teeth, and two oblique tooth surfaces (212) are respectively provided on the two circumferential sides of the wide-tooth spline (211). The radial outer wall of the wide-tooth spline (211) is an arc-shaped outer wall (213).

3. The gearbox (100) according to claim 2, characterized in that, The helical tooth surface (212) is provided with a wave groove (214) extending axially along the wide tooth spline (211).

4. The gearbox (100) according to claim 2, characterized in that, The angle (α) between the oblique tooth surface (212) of the wide tooth spline (211) and the outer wall of the tooth ring (21) is 50°-70°.

5. The gearbox (100) according to claim 1, characterized in that, The gear transmission pair (20) also includes a retaining ring (24), which is sleeved on the outer wall of the gear ring (21), and the outer wall of the retaining ring (24) forms a radial clearance fit with the inner wall of the housing (10).

6. The gearbox (100) according to claim 5, characterized in that, At least one or more of the inner wall of the housing (10), the inner wall of the spline groove (12), the oblique tooth surface (212) and the arc-shaped outer wall (213) of the wide tooth spline (211), and the outer wall of the retaining ring (24) are coated with a damping material layer.

7. The gearbox (100) according to claim 1, characterized in that, The tooth height of the wide-tooth spline (211) is greater than the keyway depth of the spline groove (12), and a radial clearance fit is formed between the tooth tip of the wide-tooth spline (211) and the bottom of the spline groove (12).

8. The gearbox (100) according to any one of claims 1 to 7, characterized in that, The outer wall of the gear ring (21) has three wide-tooth splines (211) evenly distributed circumferentially; and The inner wall of the housing (10) is provided with three spline grooves (12) in the circumferential direction.

9. The gearbox (100) according to any one of claims 1 to 7, characterized in that, The central angle of the wide tooth spline (211) ranges from 50° to 120°, and the axial width (H1) of the wide tooth spline (211) accounts for 30% to 80% of the total axial width of the tooth ring (21).

10. The gearbox (100) according to claim 1, characterized in that, The gear transmission pair (20) also includes a core gear set and a differential, and the gear ring (21) is connected to the radial outer periphery of the core gear set and the differential.

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