JP5642908B1 - Differential side gear and manufacturing method thereof - Google Patents

Abstract

By providing a differential side gear that can reliably prevent the plug member from falling off the bevel gear portion of the differential side gear, can reliably prevent leakage of hydraulic oil, and can increase the rigidity of the bevel gear portion, and a method for manufacturing the same. is there. A differential side gear of a differential gear device for an automobile includes a bevel gear portion, a cylindrical shaft portion integrally formed with the bevel gear portion, and a shaft insertion hole including a spline shaft coupling hole, the shaft insertion hole being a spline. A plug fitting hole formed in the inner wall portion of the bevel gear portion so as to communicate with the shaft coupling hole is provided, a metal plug member press-fitted into the plug fitting hole is provided, and an outer peripheral portion of the plug member is connected to the plug An annular welded portion that is liquid-tightly welded and joined to the inner peripheral wall portion of the fitting hole is provided, and the annular welded portion is formed by capacitor-type resistance welding while the plug member is press-fitted into the plug fitting hole.

Description

The present invention relates to a differential side gear of a differential gear device for an automobile and a method for manufacturing the same, and more particularly, a high-rigidity plug member that closes a plug fitting hole at an end of a shaft insertion hole of the differential side gear is welded and joined to the differential side gear in a liquid-tight manner. Related to technology.

  A differential gear device for an automobile includes a differential gear case, a ring gear fixed to the differential gear case, a pair of differential pinions that are accommodated in the differential gear case so as to face each other and are rotatably supported by a pinion shaft, and these differential pinions. And a pair of left and right differential side gears which are disposed on both left and right sides and mesh with these differential pinions.

  The differential side gear includes a bevel gear portion, a cylindrical shaft portion formed integrally with the bevel gear portion, a shaft insertion hole including a plug fitting hole and a spline shaft coupling hole communicating with the plug fitting hole, and a plug fitting. And a plug member that is fixed to the joint hole by press-fitting and tightly plugs the plug fitting hole.

In the differential gear device described in Patent Document 1, the plug fitting hole is formed to have a larger diameter than the spline shaft coupling hole, and the plug member has a partially spherical disk portion protruding toward the spline shaft coupling hole, A cylindrical mounting portion extending from the outer peripheral portion of the disk portion toward the spline shaft coupling hole and a seal member fixed to the outer peripheral surface of the mounting portion are provided. The plug member is attached by fitting the plug member attachment portion into a cylindrical plug fitting hole by press fitting. This plug member has a complicated structure and is expensive to manufacture.
In the case of the plug member shown in FIG. 11 of Patent Document 1, the structure of the plug member is complicated and the structure of the plug fitting hole is also complicated.

As shown in FIG. 6 of the present application, a plug member 101 of a conventional general differential side gear 100 is formed by pressing a thin steel plate to form a flat disk portion 101a and a spline shaft from an outer peripheral portion of the disk portion 101a. It is formed in a shallow cup shape including a short fitting cylinder portion 101b extending toward the coupling hole 100a.
The fitting cylinder part 101b has a small diameter part 101c adjacent to the disk part 101a, and a synthetic resin sealing material 102 is welded to the outer surfaces of the disk part 101a and the small diameter part 101c. The hydraulic oil is sealed so as not to leak by being fitted into the joint hole 100b by press fitting.

JP 2007-263323 A

  In the structure in which the plug member is press-fitted into the plug fitting hole without adopting a special structure for preventing the plug member from falling off as in the plug member shown in FIG. A load acting on the bevel gear from a pair of differential pinions causes the bevel gear to elastically deform from a perfect circle to a slightly distorted ellipse, and the direction of the minor axis of the ellipse (the direction connecting the pair of pinions) is frequent. fluctuate.

  Therefore, since the plug member is also repeatedly elastically deformed into an elliptical shape, there is a problem that the sealing performance of the plug member is deteriorated or the plug member is dropped from the plug fitting hole. In that case, the hydraulic oil inside the differential gear device decreases, and the differential gear device fails due to poor lubrication.

  An object of the present invention is to provide a differential side gear that can reliably prevent the plug member from falling off the bevel gear portion of the differential side gear, can reliably prevent leakage of hydraulic oil, and can increase the rigidity of the bevel gear portion, and its manufacture Is to provide a method.

The differential side gear according to claim 1 is a differential side gear of a differential gear device for an automobile, and includes a bevel gear portion, a cylindrical shaft portion integrally formed with the bevel gear portion, and a shaft insertion hole including a spline shaft coupling hole. In the differential side gear, the shaft insertion hole has a plug fitting hole formed in an inner wall portion of the bevel gear portion so as to communicate with the spline shaft coupling hole, and the plug fitting hole has a small diameter of the bevel gear portion. A metal plug member that closes the plug fitting hole is attached by press fitting so as not to protrude inward from the side end portion, and the outer peripheral portion of the plug member is welded liquid-tightly to the inner peripheral wall portion of the plug fitting hole. annular weld joint was is provided, the plug member is to reinforce the smaller diameter end of the differential side gear It is characterized in that it is constituted by a circular plate having a thickness of 3~4mm of carbon steel plate-shaped in order to increase the resistance.

The differential side gear manufacturing method according to claim 2 is a differential side gear of a differential gear device for an automobile, wherein the bevel gear portion, a cylindrical shaft portion integrally formed with the bevel gear portion, a plug fitting hole, and the plug fitting In a method of manufacturing a differential side gear including a shaft insertion hole including a spline shaft coupling hole communicating with a hole, a metal plug member for closing the plug fitting hole and reinforcing a small diameter side end portion of the differential side gear In order to increase the rigidity of the plug member, the plug member made of a flat plate made of carbon steel having a thickness of 3 to 4 mm is attached to the plug fitting hole. Resistance welding the outer peripheral portion of the plug member to the inner peripheral wall portion of the plug fitting hole while press-fitting. It is characterized.

According to the first aspect of the present invention, in the differential side gear, the metal plug member that closes the end portion of the shaft insertion hole on the bevel gear portion side and the outer peripheral portion of the plug member are liquid-tightly welded to the small-diameter side end portion of the bevel gear portion. Because it is equipped with a joined annular welded part, it is possible to reliably prevent the plug member from dropping off, the outer peripheral part of the plug member can be reliably liquid-tightly joined to the small-diameter side end of the bevel gear part, and low manufacturing costs In other words, it is possible to increase the rigidity by reinforcing the bevel gear portion with a highly rigid plug member.

  The plug member is press-fitted into a plug fitting hole formed in the inner wall portion of the bevel gear portion so as to communicate with the spline shaft coupling hole, and an outer peripheral portion of the plug member press-fitted into the plug fitting hole is formed. Since the annular welded portion welded and joined to the inner peripheral wall portion of the plug fitting hole is provided, welding can be performed while the plug member is press-fitted, and the manufacturing cost can be further reduced.

According to the invention of claim 2, the plug fitting hole (having a thickness of 3~4mm carbon steel flat circular plate) busy Gupu lug member when mounting the plug fitting hole In order to resistance weld the outer peripheral portion of the plug member to the inner peripheral wall portion of the plug fitting hole while press-fitting the plug member into the plug fitting hole, press fitting and welding are performed in one step. Can be done. And since it welds by resistance welding, it can weld with a simple welding apparatus. Therefore, the manufacturing cost can be reduced.

It is sectional drawing of the differential gear apparatus of Example 1 of this invention, and its periphery structure. It is sectional drawing of a differential side gear. It is explanatory drawing of the press-fit method which press-fits a plug member. 5 is a cross-sectional view of a differential side gear of Reference Example 1. FIG. 10 is a cross-sectional view of a differential side gear of Reference Example 2. FIG. It is sectional drawing of the conventional differential side gear.

  Hereinafter, modes for carrying out the present invention will be described based on examples.

  As shown in FIG. 1, a differential gear device 1 according to this embodiment is incorporated in the vicinity of a transmission of a front wheel drive type automobile. In addition, on the basis of the state incorporated in the automobile, the symbol L in the figure indicates the left side, and the symbol R indicates the right side.

  The differential gear device 1 includes a differential gear case 2 (hereinafter referred to as a gear case), a ring gear 4 fixed to the gear case 2 with a plurality of bolts 3, a pinion shaft 5 mounted so as to penetrate the gear case 2, and a gear case. 2, a pair of differential pinions 6 that are rotatably fitted on both ends of the pinion shaft 5, and a bevel gear portion 7 a and a cylindrical shaft portion 7 b that mesh with the pair of differential pinions 6 in the gear case 2. A pair of left and right differential side gears 7 and a pair of pinion thrust washers 8 are provided. The differential gear case 2 is filled with hydraulic oil for lubrication and cooling.

  Both left and right ends of the gear case 2 are rotatably supported by the transmission case 11 so as to rotate about the axis A of the differential gear device 1 via roller bearings 9 and oil seals 10. The drive shaft 12 inserted into each differential side gear 7 is splined to the differential side gear 7. The rotational driving force transmitted from the ring gear 4 to the pair of differential side gears 7 via the gear case 2 and the pair of differential pinions 6 is transmitted to the left and right drive shafts 12 respectively, and the left and right front wheels (not shown) rotate. Driven.

Next, the differential side gear 7 will be described in detail.
Since the left and right differential side gears 7 have a bilaterally symmetric structure, the left differential side gear 7 will be described as an example with reference to FIG.
The differential side gear 7 includes a bevel gear portion 7a, a cylindrical shaft portion 7b integrally formed with the bevel gear portion 7a and extending leftward, and a shaft insertion hole 7e including a plug fitting hole 7c and a spline shaft coupling hole 7d. ing.

  The plug fitting hole 7c is formed in the inner wall portion of the bevel gear portion 7a so as to communicate with the right end portion of the spline shaft coupling hole 7d. The plug fitting hole 7c is formed to be somewhat larger in diameter than the spline shaft coupling hole 7d. Inner spline teeth are formed on the inner periphery of the spline shaft coupling hole 7d, and the spline shaft portion 12a of the drive shaft 12 is spline coupled to the spline shaft coupling hole 7d.

A metal plug member 13 that closes the end portion of the shaft insertion hole 7e on the bevel gear portion 7a side (that is, the plug fitting hole 7c), and the outer peripheral portion of the plug member 13 is liquid-tightly connected to the small-diameter side end portion of the bevel gear portion 7a. And an annular welded portion 14 welded to each other.
The plug member 13 is formed of a carbon steel circular plate (for example, a thickness of about 3 to 4 mm). The plug member 13 is press-fitted into the plug fitting hole 7c, and the outer peripheral portion of the plug member 13 is plug-fitted. The annular wall 14 is welded in a liquid-tight manner to the inner peripheral wall of the hole 7c.

  The plug fitting hole 7c is a cylindrical hole, and the outer diameter of the plug member 13 before press-fitting is formed to be, for example, about 0.1 mm larger than the inner diameter of the plug fitting hole 7c. In order to smoothly press-fit the plug member 13, the outer surface side portion (vehicle width direction outer side portion) of the outer peripheral portion of the plug member 13 has, for example, a radial width of 1 mm and a length in the axial direction. Is a partial conical surface 13a having a diameter of 1 mm, and a partial conical surface 13a having a smaller diameter is formed toward the outside (approaching the spline shaft coupling hole), and most of the outer peripheral surface of the plug member 13 is formed on a cylindrical surface. Yes.

The operation and effect of the differential side gear 7 described above will be described.
Since the plug member 13 is a flat carbon steel member having a simple structure and the plug fitting hole 7c is also a simple cylindrical hole, the structure of the plug member 13 and the plug fitting hole 7c can be simplified.
Since the outer peripheral portion of the plug member 13 is welded to the inner peripheral wall portion of the plug fitting hole 7c by the annular welded portion 14, the end portion on the small diameter side of the bevel gear portion 7a of the shaft insertion hole 7e can be reliably joined in a liquid-tight manner. It can be implemented at a low production cost. Further, since the plug member 13 can be welded while being press-fitted, the manufacturing cost can be further reduced.

  In addition, the entire plug member 13 is accommodated in the plug fitting hole 7c, and the plug member 13 does not protrude inward (pinion shaft 5 side) from the small diameter side end portion of the bevel gear portion 7a, so the small diameter side of the bevel gear portion 7a. The end portion can be brought close to the pinion shaft 5, and the rigidity of the bevel gear portion 7a can be ensured.

  The plug member 13 is made of a steel plate having a thickness of, for example, about 3 to 4 mm, the plug member 13 is press-fitted into the plug fitting hole 7c, and the outer peripheral portion of the plug member 13 is annularly connected to the inner peripheral wall portion of the plug fitting hole 7c. Since welding is performed with the welded portion 14, the end portion on the small-diameter side of the differential side gear 7 can be reinforced by the plug member 13, so that the rigidity can be increased. The durability of the differential side gear 7 is also improved.

A method for manufacturing the differential side gear 7 will be described.
First, the differential side gear 7 without the plug member 13 is manufactured. Next, when the plug member 13 made of metal (carbon steel in this embodiment) that plugs the plug fitting hole 7c is attached to the plug fitting hole 7c, the plug member 13 is pressed into the plug fitting hole 7c, The outer peripheral portion of the plug member 13 is resistance-welded to the inner peripheral wall portion of the plug fitting hole 7c so as to be liquid-tight.

A method for performing the press-fitting and resistance welding will be specifically described with reference to FIG.
A holder member 21 made of an insulating material is previously fixed on a base member 20 made of an insulating material of the press-fitting device, and one end portion of the cylindrical shaft portion 7b of the differential side gear 7 in a vertical orientation is supported in the vertical direction of the holder member 21. The differential side gear 7 is set by being inserted into the hole 21a from above.

  Next, the plug member 13 is set at the upper end portion of the plug fitting hole 7c, the press-fitting punch 22 of the press-fitting device is brought into contact with the plug member 13, and the energization line 24 of the capacitor type resistance welding device 23 is used for press-fitting. Electrical connection is made to the punch 22 and the ground wire 25 is electrically connected to the differential side gear 7.

  In this state, the plug member 13 is pressed by lowering the press-fitting punch 22 of the press-fitting device with a strong pressing force, and a current of a predetermined magnitude is supplied from the capacitor-type resistance welding device 23 to the conducting wire 24. The current is applied to the contact portion of the outer peripheral portion of the plug member 13 and the inner peripheral wall portion of the plug fitting hole 7c and the ground wire 25, and plastic flow is generated in the contact portion by resistance heat and welded. This capacitor type resistance welding is resistance welding accompanied by diffusion welding, and the amount of heat generated is extremely small. Therefore, the temperature of the annular welded portion 14 immediately after welding and the vicinity thereof is about 80 ° C.

  Therefore, thermal distortion does not occur in the differential side gear 7 and the teeth of the differential side gear 7 are not adversely affected by heat such as tempering. Moreover, press-fitting and resistance welding can be performed in one step. Since it is welded by resistance welding, it can be welded with a simple welding device. Therefore, the manufacturing cost can be reduced.

Reference example 1

  As shown in FIG. 4, the differential side gear 7A is different from the plug member 13 only in the shape and structure of the plug member 13A. Therefore, only the shape and structure of the plug member 13A will be described. The plug member 13A is formed by press-molding a carbon steel or stainless steel plate having a thickness of about 2 to 2.5 mm, for example.

The plug member 13A includes a disk-shaped disc portion 13b and a short cylindrical portion 13c that continues from the outer peripheral portion of the disc portion 13b to the inside (the smaller diameter side of the differential side gear 7A). The plug member 7A is press-fitted into the plug fitting hole 7c, and the outer peripheral portion of the cylindrical portion 13c is welded to the inner peripheral wall portion of the plug fitting hole 7c with an annular welded portion 14A.
The method for press-fitting the plug member 13A into the plug fitting hole 7c and welding is the same as in the first embodiment.

Reference example 2

As shown in FIG. 5, the differential side gear 7B includes a structure of an annular welded portion 14B that welds and joins the plug member 13B to the small-diameter side end surface of the bevel gear portion 7a, and a welding method that welds the plug member 13B. Is different.
The plug member 13B is formed of a carbon steel circular plate (for example, a plate thickness of 2 to 4 mm) having a diameter of about 3 to 5 mm larger than the inner diameter of the plug fitting hole 7c. Is joined in a liquid-tight manner to the end surface on the small diameter side of the bevel gear portion 7a by the annular welded portion 14B.

  When this plug member 13B is welded, the plug member 13B can be rotated at a high speed while being pressed against the end surface on the small diameter side of the bevel gear portion 7a, and plastic welding can be generated by the frictional heat for diffusion welding. Alternatively, the annular welded portion 14B can be formed by using a laser beam narrowly narrowed by using a laser welding machine.

An example in which the embodiment is partially changed will be described .
The welding method for welding the plug member 7,7A in Example 1, is not limited to the capacitor resistance welding, laser welding, an ability Allowed adopt other welding techniques.

  The present invention can be applied to a differential side gear of a differential gear device for an automobile.

1 Differential gear unit
7 differential side gear 7a bevel gear portion 7b cylindrical shaft portion 7c plug fitting hole 7d spline shaft coupling hole 7e shaft insertion hole
13 plug members
14 annular welds

Claims (2)

A differential side gear of a differential gear device for an automobile, wherein the differential side gear includes a bevel gear portion, a cylindrical shaft portion formed integrally with the bevel gear portion, and a shaft insertion hole including a spline shaft coupling hole.
The shaft insertion hole has a plug fitting hole formed in an inner wall portion of the bevel gear portion so as to communicate with the spline shaft coupling hole,
A metal plug member that plugs the plug fitting hole so as not to protrude inward from the small diameter side end of the bevel gear portion is fitted into the plug fitting hole by press fitting,
An annular welded portion is provided in which the outer peripheral portion of the plug member is welded in a liquid-tight manner to the inner peripheral wall portion of the plug fitting hole ,
The differential side gear is characterized in that the plug member is constituted by a flat circular plate made of carbon steel having a thickness of 3 to 4 mm in order to reinforce the small-diameter side end portion of the differential side gear and increase rigidity . A differential side gear for a differential gear device for an automobile, comprising a bevel gear portion, a cylindrical shaft portion formed integrally with the bevel gear portion, a plug fitting hole, and a spline shaft coupling hole communicating with the plug fitting hole. In a method of manufacturing a differential side gear provided with a shaft insertion hole,
A plug member that closes the plug fitting hole, and is composed of a flat circular plate made of carbon steel having a thickness of 3 to 4 mm in order to reinforce the small-diameter side end portion of the differential side gear and increase rigidity. When attaching to the plug fitting hole,
A method of manufacturing a differential side gear, wherein the outer peripheral portion of the plug member is resistance-welded to the inner peripheral wall portion of the plug fitting hole while the plug member is press-fitted into the plug fitting hole. .

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