Differential gear

Abstract

This invention provides a differential gear that enables high rigidity in the assembly of the ring gear and differential case. [Solution] The differential gear is a differential gear in which a ring gear 11 and a differential case 12 are fixed together, and a protrusion 11A is provided on the mating surface of the ring gear 11 with the differential case 12, and a recess 12A that fits into the protrusion 11A is provided on the mating surface of the differential case 12 with the ring gear 11.

Description

Technical Field

[0001] The present invention relates to a differential gear in which a ring gear and a differential case are fixed.

Background Art

[0002] A differential gear (differential device) is a power transmission device, for example, provided in a vehicle. The differential gear absorbs the rotational difference between the left and right drive wheels that occurs because the distance traveled by the outer wheel at a corner is different from the distance traveled by the inner wheel, and realizes smooth turning.

[0003] The differential gear has an assembly of a ring gear and a differential case. The assembly of the ring gear and the differential case has the ring gear and the differential case fastened and fixed by bolts (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

【Patent Document

特許文献1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the assembly of the ring gear and the differential case, improving the loosening resistance performance of the bolts that fasten the ring gear and the differential case is an issue. At the same time, suppressing deformation of the differential case and improving the meshing posture of the gears to ensure gear strength performance are also issues.

[0006] Therefore, an object of the present invention is to provide a differential gear that can achieve high rigidity of an assembly of a ring gear and a differential case.

Means for Solving the Problems

[0007] The differential gear according to the present invention is a differential gear in which a ring gear and a differential case are fixed together, characterized in that a protrusion is provided on the mating surface of the ring gear with the differential case, and a recess that fits into the protrusion is provided on the mating surface of the differential case with the ring gear.

[0008] By adopting the above configuration, the bolt's resistance to loosening can be improved, and the gear's strength performance can be enhanced.

[0009] In the differential gear according to the present invention, it is preferable that the area of ​​the recess and window portion of the differential case overlaps in the radial direction to a large extent.

[0010] By adopting the above configuration, the rigidity of the window portion of the differential case, which is relatively less rigid than other parts, can be compensated for by the rigidity of the protruding portion of the ring gear. [Effects of the Invention]

[0011] According to the differential gear of the present invention, it is possible to achieve high rigidity in the assembly of the ring gear and the differential case. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view showing an assembly of a ring gear and a differential case, which is an example of an embodiment. [Figure 2] This is a front view of a ring gear, which is an example of an embodiment. [Figure 3] These are a front view and a top view of a differential case, which is an example of an embodiment. [Modes for carrying out the invention]

[0013] An example of an embodiment of the present invention will be described in detail below. In the following description, specific shapes, materials, directions, numerical values, etc., are examples to facilitate understanding of the present invention and can be appropriately modified according to the application, purpose, specifications, etc.

[0014] [Differential case assembly] Using Figure 1, an example of an embodiment, consisting of an assembly of a ring gear 11 and a differential case 12, will be described.

[0015] The assembly of the ring gear 11 and the differential case 12 (hereinafter referred to as the differential case assembly 10) constitutes the differential gear. The differential gear is a power transmission device and is installed, for example, in a vehicle. The vehicle of the present invention may be a gasoline vehicle, a hybrid vehicle, a plug-in hybrid vehicle, a fuel cell vehicle, an electric vehicle, etc.

[0016] The differential gear absorbs the difference in rotation between the left and right drive wheels that occurs when the distance traveled by the outer wheel and the inner wheel in a corner are different, thereby enabling smooth cornering. The differential gear may be installed on the front wheels, rear wheels, or both front and rear wheels.

[0017] A differential gear includes a ring gear 11 to which power is transmitted, a differential case 12 fixed to the ring gear 11, a pair of side gears (not shown) housed in the differential case 12 and connected to the left and right axles, and a pinion gear (not shown) connecting the pair of side gears. In a differential gear, when one of the side gears is rotated with the ring gear 11 fixed, the other side gear rotates in the opposite direction via the pinion gear.

[0018] The differential gear includes a differential case assembly 10. The differential case assembly 10 is fastened and secured to the ring gear 11 and the differential case 12 by a plurality of bolts B.

[0019] In the differential case assembly 10, it is an issue to improve the loosening resistance performance of the bolt B that fastens the ring gear 11 and the differential case 12. At the same time, it is also an issue to suppress the deformation of the differential case 12 to improve the meshing posture of the gears and ensure the gear strength performance.

[0020] In the following, each member may be described according to the axial direction and the radial direction of the ring gear 11.

[0021] [Ring Gear] Using FIG. 2, the ring gear 11 which is an example of an embodiment will be described.

[0022] Power is transmitted in the differential gear by the ring gear 11. The ring gear 11 is fixed to the differential case 12 and constitutes the differential case assembly 10. The material of the ring gear 11 is, for example, steel and the Young's modulus is 210 GPa.

[0023] A fitting structure is provided on the mating surface between the ring gear 11 and the differential case 12. More specifically, a convex portion 11A is provided on the mating surface of the ring gear 11 with the differential case 12. The convex portion 11A fits into the concave portion 12A of the differential case 12 described later.

[0024] By adopting the above configuration, the relative movement between the ring gear 11 and the differential case 12 can be suppressed. Thereby, the loosening resistance performance of the bolt B can be improved. Also, it is known that the loosening resistance performance of the bolt B improves as the thickness of the fastened object increases. Since the convex portion 11A is provided on the ring gear 11 of the present embodiment, the thickness becomes larger than that of the ring gear 11 without the convex portion 11A. Therefore, the loosening resistance performance of the bolt B can be improved compared to the ring gear 11 without the convex portion 11A.

[0025] Furthermore, by adopting the above configuration, the proportion of ring gears 11, which are high-rigidity members (for example, steel with a Young's modulus of 210 GPa), increases in the differential case assembly 10, and the proportion of differential case 12, which are low-rigidity members (for example, cast iron with a Young's modulus of 165 GPa, as described later), decreases. As a result, the gear meshing position under load is easier to maintain, and the gear strength performance can be improved.

[0026] [Differential case] Using Figure 3, we will describe a differential case 12, which is an example of an embodiment.

[0027] The differential case 12 houses a pair of side gears connected to the left and right axles in the differential gear, and a pinion gear connecting the pair of side gears. The differential case 12 is fixed to the ring gear 11 and constitutes the differential case assembly 10. The material of the differential case 12 is, for example, cast iron with a Young's modulus of 165 GPa. A window portion 12B is provided on the side of the differential case 12.

[0028] A fitting structure is provided at the mating surface between the differential case 12 and the ring gear 11. More specifically, a recess 12A is provided at the mating surface of the differential case 12 with the ring gear 11 that fits into the protrusion 11A of the ring gear 11. As a result, as described above, the loosening resistance of the bolt B can be improved, and the gear strength performance can be improved.

[0029] In the differential case 12, it is preferable that the area where the recess 12A and the window portion 12B of the differential case 12 overlap in the radial direction is large. In other words, in the differential case 12, when the recess 12A of the differential case 12 is offset axially toward the window portion 12B and the recess 12A and the window portion 12B overlap, it is preferable that the overlapping portion between the recess 12A and the window portion 12B is large.

[0030] By adopting the above configuration, the rigidity of the window portion 12B, which is relatively less rigid than other parts of the differential case 12, can be compensated for by the rigidity of the protrusion 11A of the ring gear 11.

[0031] It should be noted that the present invention is not limited to the embodiments and their modifications described above, and various changes and improvements are possible within the scope of the claims of this application. [Explanation of Symbols]

[0032] 10 Differential case assembly, 11 Ring gear, 11A Protrusion, 12 Differential case, 12A Recess, 12B Window, B Bolt

Claims

[Claim 1] A differential gear in which the ring gear and the differential case are fixed, A protrusion is provided on the mating surface of the ring gear with the differential case. The mating surface of the differential case with the ring gear is provided with a recess that fits into the protrusion. Differential gear.

Images