Differential device

Abstract

To provide a differential device that can retain a fixing pin without involving caulking of a differential case.SOLUTION: A differential device includes a differential case 20 and a pinion shaft 40. The differential case 20 has a shaft mounting hole 21 into which one end portion of the pinion shaft 40 is inserted. One end portion of the pinion shaft 40 has a shaft-side through hole 41. A case-side through hole 24 is formed in the differential case 20. A fixing pin 23 is inserted into both of the shaft-side through hole 41 and the case-side through hole 24. A pin-side recessed portion 26 is formed in an outer peripheral surface of a part of the fixing pin 23 that is inserted into the shaft-side through hole 41. An end surface 42 of the pinion shaft 40 has a shaft-side recessed portion 43 communicating with the pin-side recessed portion 26, with the shaft-side recessed portion 43 and the pin-side recessed portion 26 being filled with a retaining member 70.SELECTED DRAWING: Figure 2

Description

[[Technical Field]]

[0001] The technology disclosed in the present specification relates to a differential device. [[Background Art]]

[0002] Conventionally, as a differential device, the one described in Patent Document 1 below is known. The differential device described in Patent Document 1 includes a differential case and a pinion shaft housed in the differential case, and the pinion shaft is fixed to the differential case by inserting a fixing pin into both through holes formed respectively in the pinion shaft and the differential case. [[Prior Art Literature]] [[Patent Literature]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2017-150524 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] In the configuration of the above-mentioned Patent Document 1, it is necessary to prevent the fixing pin inserted into the through hole from coming out. Conventionally, as a method for preventing the fixing pin from coming out, for example, a method of caulking the wall portion against the fixing pin by pressing the surface of the wall portion forming the through hole in the differential case with a tool such as a punch is known. However, with such a method, when pressing the tool, there is a concern that the tool slips on the surface of the wall portion and dents are formed in locations other than the predetermined position. There is also a concern that the differential case may crack due to the load when pressing the tool.

[0005] The technology disclosed in the present specification has been completed based on the above circumstances, and an object thereof is to provide a differential device capable of preventing a fixing pin from coming off without caulking the differential case. [Means for solving the problem]

[0006] As a means to solve the above problems, the differential device disclosed herein comprises a differential case, a pinion shaft housed in the differential case, and a fixing pin for fixing the pinion shaft to the differential case, wherein the differential case has a shaft mounting hole into which one end of the pinion shaft is inserted, and the one end of the pinion shaft has a shaft-side through hole through which the pinion shaft penetrates in a direction intersecting the axial direction of the pinion shaft, and the differential case has a front In the wall portion constituting the shaft mounting hole, a case-side through hole is formed at a location opposite to the shaft-side through hole, the fixing pin is inserted through both the shaft-side through hole and the case-side through hole, a pin-side recess is formed on the outer circumferential surface of the portion of the fixing pin inserted through the shaft-side through hole, a shaft-side recess communicating with the pin-side recess is formed on the end face of the one end of the pinion shaft, and a retaining member is filled in the shaft-side recess and the pin-side recess to prevent the fixing pin from coming out of the pinion shaft.

[0007] By filling both the shaft-side recess and the pin-side recess with retaining material, the fixing pin can be prevented from coming loose from the pinion shaft via the retaining material. Furthermore, since the shaft-side recess is provided on the end face of the pinion shaft, the retaining material can be easily inserted into the shaft-side recess, resulting in good workability. As described above, with the above configuration, the fixing pin can be prevented from coming loose without crimping the differential case.

[0008] Furthermore, the retaining member can be made of adhesive. Since the fixing pin and the pinion shaft can be bonded together with adhesive, the fixing pin can be more reliably prevented from coming loose.

[0009] Furthermore, the fixing pin may be cylindrical in shape, and the pin-side recess may extend over the entire circumference of the fixing pin. If the pin-side recess is provided only on a portion of the fixing pin's circumference, it becomes necessary to adjust the rotation angle of the fixing pin around its axis so that the shaft-side recess and the pin-side recess communicate when inserting the fixing pin into the shaft-side through hole. In the above configuration, since the pin-side recess is provided over the entire circumference of the fixing pin, the shaft-side recess and the pin-side recess can be connected regardless of the rotation angle of the fixing pin around its axis.

[0010] Furthermore, the shaft-side through-hole can be formed to intersect with the midpoint of the depth direction of the shaft-side recess. When filling with the retaining member, it can be filled from the front of the shaft-side recess, through the pin-side recess, to the back of the shaft-side recess. This allows the entire circumference of the fixing pin to be covered with the retaining member, and the retaining member to be locked to the edge of the case-side through-hole on the inner surface of the shaft-side recess, thereby more reliably preventing the fixing pin from coming loose. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a differential device that can prevent the fixing pin from coming loose without crimping the differential case. [Brief explanation of the drawing]

[0012] [Figure 1] Cross-sectional view of a differential device according to one embodiment of the present invention. [Figure 2] A cross-sectional view of the area near the fixing pin when the retaining material has not been filled. [Figure 3] Cross-sectional view of the area near the fixing pin (enlarged view of the area near the fixing pin in Figure 1) [Figure 4] Cross-sectional view of the fixing pin after cutting the middle section (corresponding to the view cut along line IV-IV in Figure 3) [Modes for carrying out the invention]

[0013] One embodiment of the present invention will be described with reference to Figures 1 to 4. The differential device 10 (differential unit) of this embodiment is mounted on a vehicle such as an automobile, and as shown in Figure 1, comprises a differential case 20, a ring gear 11, a cylindrical pinion shaft 40 housed in the differential case 20, a fixing pin 23 for fixing the pinion shaft 40 to the differential case 20, a pair of pinion gears 51, 52, a pair of side gears 13, 14, and a pair of washers 61, 62.

[0014] The differential case 20 is formed, for example by casting, and has a roughly box-like shape with a housing space S1. More specifically, the differential case 20 has a roughly box-like shape with openings on both sides in the direction perpendicular to the plane of the paper in Figure 1 (a direction perpendicular to both the axial direction of the pinion shaft 40 and the axial direction of the drive shafts 15 and 16). The housing space S1 houses the pinion shaft 40, a pair of side gears 13 and 14, and a pair of pinion gears 51 and 52.

[0015] A pair of pinion gears 51 and 52 are each rotatably mounted on the pinion shaft 40. In other words, the pinion shaft 40 constitutes the axis of rotation for the pinion gears 51 and 52. A pair of side gears 13 and 14 are each positioned opposite each other with a gap between them in the left-right direction of the vehicle (left-right direction in Figure 1). Drive shafts 15 and 16 are connected to the side gears 13 and 14, respectively, by spline fitting or the like. The drive shafts 15 and 16 are also inserted through through holes 20A and 20A formed in the differential case 20, respectively.

[0016] The pinion shaft 40 extends in a direction perpendicular to the left-right direction of the vehicle (left-right direction in Figure 1), and the pair of pinion gears 51 and 52 are positioned opposite each other with a gap in the longitudinal direction of the pinion shaft 40 (up-down direction in Figure 1). The pair of side gears 13 and 14 are positioned to sandwich the pinion gears 51 and 52 from the left and right, and mesh with the pinion gears 51 and 52, respectively. Meanwhile, a ring gear 11 is attached to the flange portion 20G of the differential case 20. The drive pinion 12 meshes with the ring gear 11.

[0017] The rotation of the engine mounted on the vehicle is transmitted to the ring gear 11 via the drive pinion 12, causing the ring gear 11 to rotate. As a result, the differential case 20 rotates around a pivot axis that runs in the left-right direction, and the drive shafts 15 and 16 rotate accordingly. Furthermore, when the vehicle turns a corner, the difference in the load acting on the left and right drive shafts 15 and 16 causes a pair of pinion gears 51 and 52 to rotate, resulting in a difference in the rotational speed of the drive shafts 15 and 16.

[0018] A pair of pinion gears 51 and 52 are externally fitted onto the pinion shaft 40. A washer 61 is interposed between pinion gear 51 and the inner surface of the differential case 20, and a washer 62 is interposed between pinion gear 52 and the inner surface of the differential case 20. On the inner surface of the differential case 20, a recess 20D is formed where washer 61 is placed, and a recess 20E is formed where washer 62 is placed. Washer 61 is fitted into recess 20D, and washer 62 is fitted into recess 20E.

[0019] As shown in FIG. 1, the washer 61 is formed into a curved shape conforming to the outer peripheral surface of the pinion gear 51, and the washer 62 is formed into a curved shape conforming to the outer peripheral surface of the pinion gear 52. The pinion gear 51 is configured to be slidable relative to the washer 61, and the pinion gear 52 is configured to be slidable relative to the washer 62. It should be noted that a lubricant is configured to be supplied between the pinion gear 51 and the washer 61, and between the pinion gear 52 and the washer 62, respectively. The pinion shaft 40 is press-fitted into the insertion hole 61A of the washer 61, the through holes 51A and 52A of the pinion gears 51 and 52, and the insertion hole 62A of the washer 62, respectively.

[0020] The pinion shaft 40 is made of, for example, an alloy material. Further, the washers 61 and 62 are made of, for example, a steel plate. It should be noted that the materials of the differential case 20, the pinion shaft 40, and the washers 61 and 62 are not limited to those described above, and can be appropriately changed.

[0021] The pinion shaft 40 has a cylindrical shape. In the wall portion constituting the differential case 20, a shaft mounting hole 21 into which one end 40A of the pinion shaft 40 is inserted and a shaft mounting hole 22 into which the other end 40B of the pinion shaft 40 is inserted are respectively formed through the wall portion. In the one end 40A (the upper end in FIG. 1) of the pinion shaft 40, a shaft-side through hole 41 that penetrates the pinion shaft 40 in a radial direction (a direction intersecting the axial direction of the pinion shaft 40) is formed.

[0022] As shown in FIG. 3, in the differential case 20, a pair of case-side through holes 24 and 25 are formed at a position facing the shaft-side through hole 41 in the wall portion 20B constituting the shaft mounting hole 21. More specifically, the case-side through hole 24 is provided so as to face one end of the shaft-side through hole 41, and the case-side through hole 25 is provided so as to face the other end of the shaft-side through hole 41. The fixing pin 23 is inserted through the shaft-side through hole 41 and the case-side through holes 24 and 25. Thereby, the pinion shaft 40 is fixed to the differential case 20.

[0023] In the fixing pin 23, a pin-side recess 26 is formed on the outer peripheral surface of the axially intermediate portion 23A (the portion inserted into the shaft-side through hole 41). The fixing pin 23 has a cylindrical shape, and the pin-side recess 26 extends over the entire circumferential perimeter of the fixing pin 23. Therefore, in the intermediate portion 23A of the fixing pin 23, the diameter gradually decreases toward the center in the length direction of the fixing pin 23.

[0024] On an end face 42 on the one end 40A side of the pinion shaft 40, a shaft-side recess 43 communicating with the pin-side recess 26 is formed. A bottom surface 43D of the shaft-side recess 43 is disposed below the shaft-side through hole 41 (on the inner side of the pinion shaft 40). Therefore, the shaft-side through hole 41 is formed so as to be orthogonal (intersect) to a depthwise intermediate portion 43A (see FIG. 2) of the shaft-side recess 43. The shaft-side recess 43 has a circular shape in plan view, and as shown in FIG. 3, an opening 43B of the shaft-side recess 43 has a shape whose diameter gradually increases toward the opening end. Further, the shaft-side recess 43 is provided along the central axis of the pinion shaft 40.

[0025] As shown in FIG. 3, the shaft-side recess 43 and the pin-side recess 26 are filled with a retaining member 70 that prevents the fixing pin 23 from coming off relative to the pinion shaft 40. The retaining member 70 is constituted by, for example, an adhesive. Therefore, the retaining member 70 is bonded to both the inner surface of the shaft-side recess 43 and the inner surface of the pin-side recess 26 (the outer peripheral surface of the fixing pin).

[0026] As shown in Figure 2, the retaining member 70 can be formed by pouring uncured adhesive into the opening 43B of the shaft-side recess 43 with the fixing pin 23 inserted through the shaft-side through hole 41, and then allowing it to cure. As the adhesive used for the retaining member 70, for example, an adhesive that hardens by drying or a two-part mixed type can be used. In addition, the width of the pin-side recess 26 (length in the left-right direction in Figure 3, length along the axial direction of the fixing pin 23) is set to a value such that the pin-side recess 26 overlaps with the case-side through holes 24 and 25. This allows the retaining member 70 to be locked to the inner surface of the case-side through holes 24 and 25, thereby increasing the strength of the retaining member 70.

[0027] Next, the effects of this embodiment will be described. By filling both the shaft-side recess 43 and the pin-side recess 26 with the retaining member 70, the fixing pin 23 can be prevented from coming out of the pinion shaft 40 via the retaining member 70. Furthermore, since the shaft-side recess 43 is provided on the end face 42 of the pinion shaft 40, as shown in Figure 2, the retaining member 70 before hardening can be easily poured into the shaft-side recess 43 with the fixing pin 23 inserted through the shaft-side through hole 41, resulting in good workability. Thus, in this embodiment, the fixing pin 23 can be prevented from coming out without crimping the differential case 20.

[0028] Furthermore, the retaining member 70 is made of adhesive. The adhesive allows the fixing pin 23 and the pinion shaft 40 to be bonded together, thus more reliably preventing the fixing pin 23 from coming loose.

[0029] Furthermore, the fixing pin 23 is cylindrical in shape, and the pin-side recess 26 extends along the entire circumference of the fixing pin 23. If the pin-side recess 26 were provided only on a portion of the fixing pin 23 in the circumferential direction, it would be necessary to adjust the rotation angle of the fixing pin 23 around its axis so that the shaft-side recess 43 and the pin-side recess 26 communicate when inserting the fixing pin 23 into the shaft-side through hole 41. In this embodiment, since the pin-side recess 26 is provided along the entire circumference of the fixing pin 23, the shaft-side recess 43 and the pin-side recess 26 can communicate regardless of the rotation angle of the fixing pin 23 around its axis.

[0030] Furthermore, the shaft-side through-hole 41 is formed to intersect with the midpoint of the depth direction of the shaft-side recess 43. When filling with the retaining member 70, it is possible to fill the retaining member 70 from the front side of the shaft-side recess 43, through the pin-side recess 26, and into the back of the shaft-side recess 43. As a result, as shown in Figure 4, the entire circumference of the fixing pin 23 is covered with the retaining member 70, and as shown in Figure 3, the retaining member 70 can be locked to the edge 24A of the case-side through-hole 24 and the edge 25A of the case-side through-hole 25 on the inner surface of the shaft-side recess 43, thereby more reliably preventing the fixing pin 23 from coming loose.

[0031] <Other Embodiments> The technologies disclosed herein are not limited to the embodiments described above in the description and drawings, but also include, for example, the following embodiments.

[0032] (1) In the above embodiment, an adhesive was given as an example for the retaining member 70, but it is not limited to this. The retaining member can be any material that has the property of hardening after being filled into both the shaft-side recess 43 and the pin-side recess 26, for example, putty may be used. (2) In the above embodiment, the fixing pin 23 is shown to be cylindrical, but the shape of the fixing pin 23 can be changed as appropriate. (3) In the above embodiment, a configuration in which the shaft-side recess 43 and the shaft-side through hole 41 are perpendicular to each other was illustrated, but the embodiment is not limited thereto. The bottom of the shaft-side recess 43 may also be directly connected to the shaft-side through hole 41. [Explanation of Symbols]

[0033] 10...Differential device, 20...Differential case, 21...Shaft mounting hole, 23...Fixing pin, 24...Case side through hole, 26...Pin side recess, 40...Pinion shaft, 41...Shaft side through hole, 42...End face on one end of the pinion shaft, 43...Shaft side recess, 70...Retaining member

Claims

1. Differential case and The pinion shaft housed in the differential case, The pinion shaft is fixed to the differential case by a fixing pin, The differential case has a shaft mounting hole into which one end of the pinion shaft is inserted. One end of the pinion shaft has a shaft-side through hole formed therein, through which the pinion shaft penetrates in a direction intersecting the axial direction of the pinion shaft. In the differential case, a case-side through-hole is formed in the wall portion constituting the shaft mounting hole, at a location facing the shaft-side through-hole. The aforementioned fixing pin is inserted through both the shaft-side through hole and the case-side through hole. In the aforementioned fixing pin, a pin-side recess is formed on the outer circumferential surface of the portion inserted through the shaft-side through hole. A shaft-side recess communicating with the pin-side recess is formed on the end face of the pinion shaft on the one end side. A differential device in which the shaft-side recess and the pin-side recess are filled with retaining members that prevent the fixing pin from coming out of the pinion shaft.

2. The differential device according to claim 1, wherein the retaining member is made of an adhesive.

3. The aforementioned fixing pin is cylindrical in shape. The differential device according to claim 1 or claim 2, wherein the pin-side recess extends over the entire circumference in the circumferential direction of the fixing pin.

4. The differential device according to claim 3, wherein the shaft-side through hole is formed in such a manner that it intersects with the intermediate portion in the depth direction of the shaft-side recess.

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