JPH0596592U - Differential pinion shaft - Google Patents

Abstract

(57) [Abstract] [Purpose] When the differential is put into a rest state for a long time and then restarted, the initial lubrication between the shaft hole of the pinion gear and the journal part of the pinion shaft is improved to prevent wear and loss of both. Preventing seizure [Configuration] The pair of upper and lower pinion gears 7 are arranged in opposite directions to each other by allowing the shaft holes 11 penetrating through the centers of the pinion gears 7 to loosely fit in the respective journal portions 6 of the pinion shaft 5 with a minute clearance. It can slide and rotate. Each journal portion 6 is provided with a total of 12 dimples 12 arranged in three rows in the axial direction and four rows in the circumferential direction. Lubricating oil 13 is supplied to the clearance, and the lubricating oil 13 is held in each dimple 12 for a long time.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pinion shaft of a pinion gear used in a differential device.

[0002]

[Prior Art]

 The differential gear mounted on the center of the drive wheel axle of an automobile is equipped with a pair of pinion gears for absorbing the difference in rotational speed between the left and right drive wheel axles. The pair of pinion gears have shaft holes penetrating at the center of each pinion gear loosely fitted in the journals near both ends of the pinion shaft with a small clearance so that they can slide and rotate in opposite directions. Is becoming Then, in order to reduce the frictional force between the pinion gear and the pinion shaft and to improve wear resistance, fluid lubrication between them is achieved, and the pinion shaft is carburized and quenched, and soft nitrided. Surface treatment such as treatment (tuftride), Ni-P plating treatment, and phosphate coating treatment is performed.

[0003]

[Problems to be solved by the device]

 However, since a small amount of lubricating oil can be supplied to the minute clearance between the shaft hole of the pinion gear and the journal part of the pinion shaft, the motor vehicle was stopped and the differential was put into a dormant state for a long time. In this case, the initial lubrication between the pinion gear and the pinion shaft is not sufficiently performed when the vehicle is started and then the curve is re-actuated and the differential is re-actuated. Since it is difficult to withstand the contact, there is a concern that both of them may wear or seize.

Incidentally, as shown in FIGS. 3 and 4, the journal portion 52 of the pinion shaft 51 is provided with a dihedral width portion 53, and as shown in FIG. A method of supplying a sufficient amount of lubricating oil 57 to the width portion 53 or the spiral oil groove 54 to positively lubricate the shaft hole 56 of the pinion gear 55 is also under study. However, in the shape extending in the axial direction of the pinion shaft 51 like the double width portion 53 or the spiral groove 54, the lubricating oil 57 is transmitted through the double width portion 53 and the like while the differential device is at rest. Since it is easy to fall, the above problems could not be solved.

An object of the present invention is to solve the above problems and improve initial lubrication between the shaft hole of the pinion gear and the journal portion of the pinion shaft when the differential device is rested for a long time and then re-activated. The purpose of the present invention is to provide a pinion shaft capable of preventing wear and seizure of both.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, in the pinion shaft of the differential device of the present invention, a plurality of dimples are provided in the journal portion of the pinion shaft in which the shaft hole of the pinion gear slides and rotates.

[0007]

[Action]

 Lubricating oil is supplied to the minute clearance between the shaft hole of the pinion gear and the journal portion of the pinion shaft, and the lubricating oil is held by the dimples. Then, even when the differential device is in a rest state for a long period of time, the lubricating oil remains held in the dimples. Therefore, when the differential device is restarted next time, the initial lubrication between the pinion gear and the pinion shaft is sufficiently performed.

[0008]

【Example】

 An embodiment in which the present invention is embodied in a differential device mounted on the center of a drive wheel axle of an automobile will be described with reference to FIGS. 1 and 2. The differential device 1 includes a ring gear 3 that meshes with a drive gear 2 and rotates about a horizontal axis, a case 4 that rotates together with the ring gear 3, and a pinion shaft that is attached to the case 4 in a direction orthogonal to the axis. 5, a pair of upper and lower bevel tooth pinion gears 7 arranged on journals 6 near both ends of the pinion shaft 5, and a pair of left and right bevel tooth side gears 8 that mesh with both pinion gears 7 and rotate about a horizontal axis. It consists of and. Left and right drive wheel shafts (not shown) are slidably inserted through the left and right shaft holes 9 of the case 4, and the inner ends of the left and right drive wheel shafts are attached to the shaft holes 10 of the both side gears 8 by a spline structure. It is designed to be used.

The pair of upper and lower pinion gears 7 have a shaft hole 11 penetrating at the center of each pinion gear 7 and a minute clearance in each journal portion 6 of the pinion shaft 5 (for the sake of convenience, it is shown larger than the actual size in FIG. 1). By being loosely fitted in, they can slide and rotate in opposite directions. Further, each journal portion 6 of the pinion shaft 5 is provided with a total of 12 dimples 12 arranged in three rows in the axial direction and four rows in the circumferential direction, and each dimple 12 has a diameter of about 3 mm. The depth is about 0.5 mm. However, the number of the dimples 12, the arrangement method, the size, and the like can be appropriately changed. Lubricating oil 13 is supplied to the clearance between the pinion gear 7 and the pinion shaft 5, and the lubricating oil 13 is held by each dimple 12.

Then, even when the vehicle is stopped and the differential device 1 is put into a rest state for a long period of time, the lubricating oil 13 remains retained in each dimple 12. Therefore, when the motor vehicle is started next, the curve is bent, and the differential gear 1 is re-activated, the initial lubrication between the pinion gear 7 and the pinion shaft 5 is sufficiently performed, and the wear of both of them is caused. It is possible to prevent the seizure.

Note that the present invention is not limited to the configuration of the above-described embodiment, and may be appropriately modified within a range not departing from the spirit of the invention, for example, by using it in combination with a double-width portion or a spiral groove of the prior art. It can also be converted.

[0012]

[Effect of the device]

 Since the pinion shaft of the present invention is configured as described above, when the differential device is left in a rest state for a long period of time and then restarted, the initial lubrication between the shaft hole of the pinion gear and the journal portion of the pinion shaft is prevented. It is possible to improve and prevent wear and seizure of both.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a pinion shaft and a pinion gear of an embodiment embodying the present invention.

FIG. 2 is a cross-sectional view of the entire differential device using the pinion shaft.

FIG. 3 is a cross-sectional view of essential parts showing a pinion shaft and a pinion gear that have been conventionally studied.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a cross-sectional view of essential parts showing another pinion shaft and a pinion gear that have been conventionally studied.

[Explanation of symbols]

1 Differential device 5 Pinion shaft 6 Journal part 7 Pinion gear 11 Shaft hole 12 Dimple

Claims (1)

[Scope of utility model registration request] 1. A pinion shaft of a differential gear, wherein a plurality of dimples are provided in a journal portion of a pinion shaft in which a shaft hole of a pinion gear rotates.