JPH1172158A - Differential case structure of differential gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a differential case having high strength and tooth face precision by a small facility by assembling and constituting a differential case main body formed integrally by forging a cylindrical part which supports a pinion shaft and a ring gear part and cover members which support right and left axle shafts, respectively. SOLUTION: A differential gear 1 consists of a differential case main body 2, a right cover member 7, and a left cover member 8, and the main body 2 is manufactured by forging a cylindrical part 3 which supports a pinion shaft 20 and an annular ring gear part 4 integrally. They are assembled by inserting the member 7 through a left opening of the main body 2, moving it up to a right opening, fitting and positioning a peripheral wall 7a on a right inner peripheral face 3c of the cylindrical part 3, and press fitting and fixing it until a flange 7d comes in contact with a stepped part. As for the member 8, a flange 8d is brought in contact with a fitting stepped part on a left inner peripheral face 3d of the main body 2, a caulked part 5 is bent to a central side, and a part 5a corresponding to a groove strap 8f of the flange 8d is caulked on it. Consequently, it is possible to position a differential case simply and securely and achieve the assembly with high axial precision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential case structure in a differential device interposed in a drive system of an automobile.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional example (JP-A-62-132055) showing a differential case structure of a differential device.
In this differential device 01, the differential case main body 02 has a bottomed cylindrical shape, the outer peripheral edge of the opening extends in the centrifugal direction, and a ring gear portion 02c is integrally formed by forging. A cover member 03 that covers the opening of 02 is fixed to the differential case main body 02 with bolts 04.

The differential case main body 02 has a support hole for supporting a pinion shaft 05 in a cylindrical portion 02a, and a bearing for supporting an axle shaft 06 is formed in a bottom portion 02b. On the other hand, the cover member 03 has a coaxial bearing formed at the center corresponding to the bearing of the differential case main body 02.

In general, the differential case main body and the ring gear are separately fixed by bolts or the like.
In the case of 01, since the differential case body 02 forges the ring gear portion 02c integrally, high strength is obtained, and miniaturization and weight reduction are possible.

[0005]

However, the differential case main body 02 has a bottom portion 02 provided with a bearing for supporting the axle shaft.
Since b is also integrally forged, the ring gear 02c formed integrally with the ring b is easily distorted, and the tooth surface accuracy cannot be maintained high. Further, since the differential case body 02 has both the ring gear portion 02c and the bottom portion 02b, the forging volume is increased, the size of the mold and equipment is increased, and the durability of the mold is not good.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to forge and manufacture a differential case having high strength and high tooth surface accuracy of a ring gear with relatively simple and small equipment. The difference is that the differential case structure is provided.

[0007]

In order to achieve the above-mentioned object, the present invention provides a differential case body in which a cylindrical portion for supporting a pinion shaft and a ring gear portion are integrally formed by forging, Left and right cover members respectively supporting the axle shafts of the differential case, and the left and right cover members are respectively assembled to left and right openings of the differential case main body to constitute a differential case. Structured.

Since the cylindrical portion and the ring gear portion are integrally formed by forging, a high-strength differential case main body can be manufactured, and the bottom supporting the axle shaft is integrally formed with the differential case main body. Since forging is not performed, distortion of the ring gear forming portion does not occur, and high tooth surface accuracy can be maintained.

Since the differential case body does not have a bottom portion having an axle shaft bearing, the forging volume is not large, and it is possible to avoid an increase in the size of the mold and equipment, and the mold has high durability. In addition, a small and lightweight differential case body can be manufactured with high accuracy.

According to a second aspect of the present invention, in the differential case structure of the first aspect, at least one of the left and right cover members is caulked and fixed to the differential case body. It is characterized by that.

Since the cover member is fixed to the main body of the differential case by caulking, assembly is easy without separately requiring members such as bolts, and there is no need to provide a bolt for preventing loosening.

According to a third aspect of the present invention, in the differential case structure of the first aspect, at least one of the left and right cover members is fixed to the differential case body by press fitting. It is characterized by the following.

Since the cover member is fixed to the main body of the differential case by press-fitting, it is easy to assemble without additional members such as bolts, and a plurality of bolts can be reduced, resulting in a small size and light weight.

According to a fourth aspect of the present invention, in the differential case structure of the differential device according to the second or third aspect, the left and right cover members are provided in the left and right coaxial cylindrical openings of the differential case main body. Are positioned by fitting the respective circular outer peripheral portions.

Since the circular outer peripheral portions of the left and right cover members fit into the cylindrical openings of the differential case main body and are positioned with each other, simple and reliable positioning and high-precision assembly can be easily performed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to FIGS. In the differential device 1 according to the present embodiment, the differential case includes the differential case main body 2 and the right cover member 7 and the left cover member 8. Note that the left and right in FIG.

The differential case body 2 includes a pinion shaft 20.
And a ring gear portion 4 whose right opening end extends in the centrifugal direction and is formed in an annular shape is integrally formed by forging.

The inner peripheral surface of the cylindrical portion 3 of the differential case body 2
The right side of the central inner peripheral surface 3b forms a slightly smaller diameter inner peripheral surface 3c via a step, and the left side forms a larger diameter left inner peripheral surface 3d via a step. Particularly, the left side portion of the cylindrical portion 3 forms a thin cylindrical caulking portion 5 by the large-diameter left inner peripheral surface 3d.

On the other hand, the right cover member 7 is generally formed of a flat cylindrical peripheral wall 7a, a hollow bottom wall 7b having a shallow bottom, and a cylindrical portion 7c having a hollow opening edge of the bottom wall 7b extending in the axial direction.
An opening end of the peripheral wall 7a is formed with a flange 7d whose diameter is slightly enlarged, and a concentric inner peripheral wall 7e protrudes from the bottom wall 7b inside the peripheral wall 7a to form an annular concave portion with the outer peripheral wall 7a. .

The outer diameter of the peripheral wall 7a is slightly larger than the right inner peripheral surface 3c of the differential case main body 2 and can be fitted by press fitting, and the outer diameter of the flange 7d is equal to the inner diameter of the central inner peripheral surface 3b. The inner diameter of the cylindrical portion 7c is slightly larger than the outer diameter of the right axle shaft, and the right axle shaft is penetrated.

On the other hand, the left cover member 8 is generally formed of a flat cylindrical peripheral wall 8a, a hollow bottom wall 8b having a shallow bottom, and a cylindrical portion 8c having a hollow opening edge of the bottom wall 8b extending in the axial direction.
An opening end of the peripheral wall 8a is formed with a flange 8d having a large diameter, and a concentric inner peripheral wall 8e is formed inside the peripheral wall 8a.
And an annular concave portion is formed between the outer peripheral wall 8a and the outer peripheral wall 8a.

Further, six grooves 8f are formed in the radial direction by notching the peripheral wall 8a at six equal intervals. Each groove 8f has a predetermined width and has a flange 8d and an inner peripheral wall 8.
e also cuts out at the same time, extends in the centrifugal direction from the hollow portion, and reaches the outside.

The outer diameter of the greatly expanded flange 8d is equal to the inner diameter of the left inner peripheral surface 3d of the differential case body 2, and the inner diameter of the cylindrical portion 8c is slightly larger than the outer diameter of the left axle shaft. Penetrated.

To assemble the right cover member 7 to the differential case main body 2, first insert the right cover member 7 from the left opening of the differential case main body 2 and move to the right opening to move the right cover member 7 to the right side of the cylindrical portion 3. The peripheral wall 7a is fitted and positioned on the inner peripheral surface 3c, and is press-fitted and fixed until the flange 7d contacts the step.

The peripheral wall 7a is fitted to the inner peripheral surface 3c on the right side of the cylindrical portion 3 so that positioning can be performed easily and reliably, high-accuracy mounting can be performed, and the press-fitting can be performed easily without the need for bolts or the like. Can be attached.

The left cover member 8 has a flange 8
d is fitted and positioned on the left inner peripheral surface 3d of the differential case body 2 and abuts on the stepped portion. Then, the caulked portion 5 is connected to the flange 8
The part 5a corresponding to the six cutout grooves 8f of the flange 8d is further bent into the groove 8f and bent and crimped to the center side along the outer peripheral edge of d.

As described above, the annular flange 8d is fitted to the left inner peripheral surface 3d of the cylindrical portion 3 so that positioning can be performed simply and reliably, and assembly with high shaft accuracy can be performed. And by crimping, the assembling work can be easily performed without the need for bolts and the like.

The crimped and crimped portion 5 which is bent along the outer peripheral edge of the flange 8d has wrinkles due to a decrease in diameter, and furthermore, six portions 5a of the crimped portion 5 have grooves 8 formed therein.
The wrinkles are extended by biting into f. Also, since the six portions 5a of the caulking portion 5 bite into the groove 8f, the relative rotation of the left cover member 8 with respect to the differential case main body 2 is prohibited, and the fastening can be securely performed.

In the differential case thus assembled, both ends of the pinion shaft 20 are supported by a pair of through holes 3a, 3a formed in the cylindrical portion 3 of the differential case main body 2. A pair of pinion gears 21 and 22 are rotatably supported by the pinion shaft 20 and a pair of side gears 25 and 26 meshing with the respective pinion gears 21 and 22 in a bevel gear system. It is positioned so as to sandwich the reference numeral 20, and is rotatably supported by the right cover member 7 and the left cover member 8, respectively.

A multi-plate clutch 30 and a disc spring 31 are interposed between the rear surface of the bevel gear portion of the right side gear 25 and the bottom wall 7b of the right cover member 7 so as to provide an appropriate rotation resistance. Similarly, a multi-plate clutch 32 and a disc spring 33 are interposed between the left side gear 26 and the bottom wall 8b of the left cover member 8 so as to provide an appropriate rotation resistance.

As described above, the differential case can be easily assembled by press-fitting the right cover member 7 into the differential case main body 2 and caulking the left cover member 8.

The differential case body 2 is formed by integrally forging the cylindrical portion 3 and the ring gear portion 4 and has high strength, and the bottom portion supporting the axle shaft is forged integrally with the differential case body 2. Since it is not molded, a precise tooth surface can be formed without causing distortion in the formation portion of the ring gear portion 4.

Further, since the differential case main body 2 does not have a bottom portion provided with an axle shaft bearing, the forging volume is not large, and it is possible to avoid an increase in the size of the mold and equipment, and the mold has high durability. Furthermore, a small and lightweight differential case body can be manufactured with high precision.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a differential device according to an embodiment of the present invention.

FIG. 2 is a right side view of the differential device.

FIG. 3 is a left side view of the differential device.

FIG. 4 is a cross-sectional view of a conventional differential device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Differential device, 2 ... Differential case main body, 3 ... Cylindrical part, 4 ...
Ring gear part, 5 ... caulking part, 7 ... right side cover member, 8
... left cover member, 20 ... pinion shaft, 21, 22 ... pinion gear, 25, 26 ... side gear, 30 ... multi-plate clutch,
31: Disc spring, 32: Multi-plate clutch, 33: Disc spring.

Claims (4)

[Claims] 1. A differential case main body in which a cylindrical portion supporting a pinion shaft and a ring gear portion are integrally formed by forging, and left and right cover members respectively supporting left and right axle shafts. A differential case structure for a differential device, wherein the left and right cover members are respectively assembled to left and right openings of a case body to form a differential case. 2. The differential case structure according to claim 1, wherein at least one of the left and right cover members is caulked and fixed to the differential case body. 3. The differential case structure according to claim 1, wherein at least one of the left and right cover members is fixed to the differential case body by press-fitting. 4. The positioning according to claim 2, wherein circular outer peripheral portions of the left and right cover members are fitted into right and left coaxial cylindrical openings of the differential case main body, respectively. 4. The differential case structure of the differential device according to 3.