JP3693566B2 - Lubrication structure of differential gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lubricating structure for a differential gear that can supply the sufficient quantity of oil to a pinion shaft, using the flow of oil splashed by a ring gear even if using a die-cast differential carrier. SOLUTION: The ring gear 15 mounted to a differential case is provided, and oil inside a differential carrier 1 is splashed by the ring gear 15 and led into a pinion shaft chamber 3. An oil lead-in chamber 21 for receiving the oil splashed by the ring gear 15 is provided at the inner side face of the differential carrier 1, in a position offset onto the ring gear 15 side from the pinion shaft chamber 3, and the lower end part of the oil lead-in chamber 21 is extended into a position downward from the top part of the pinion shaft chamber 3. The lower end part of the oil lead-in chamber 21 is provided with an oblique oil hole 23 passing through from the oil lead-in chamber 21 toward the pinion shaft chamber 3, and the inner side face of the oil lead-in chamber 21 is inclined so that oil entering the oil lead-in chamber 21 flows toward the oil hole 23.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lubricating structure for a differential device, and more particularly to a structure for lubricating a bearing and an oil seal accommodated in a pinion shaft chamber of a differential carrier.
[0002]
[Prior art]
Conventionally, as a differential for a rear wheel of an automobile, a differential carrier, a differential cover attached to the differential carrier, a pinion shaft supported by a pinion shaft chamber of the differential carrier via a bearing, and having a pinion gear at one end, Some include a differential case that is pivotally supported by the bearing support portion of the differential carrier, and a ring gear that meshes with the pinion gear and is attached to the differential case.
[0003]
In such a differential device, in order to lubricate the bearings and oil seals that support the pinion shaft, the oil accumulated in the space between the differential carrier and the differential cover is used as a ring gear as disclosed in JP-A-2000-104808. It is known that it is lifted up and introduced into the pinion shaft chamber. This differential device uses a die-cast differential carrier. An oil introduction chamber is provided on the inner surface of the differential carrier to receive the oil pumped up by the ring gear. An oil introduction chamber is provided at the lower end of the oil introduction chamber. It has a structure in which a vertical oil hole is provided that penetrates from the introduction chamber toward the pinion shaft chamber and opens at the top of the pinion shaft chamber.
[0004]
[Problems to be solved by the invention]
However, since the oil introduction chamber having the above structure is provided in the upper part of the pinion shaft chamber, the opening dimension in the vertical direction of the oil introduction chamber is small, and the oil pumped up by the ring gear does not necessarily enter the oil introduction chamber smoothly. Absent. In addition, since the differential carrier is made of die-cast, the oil introduction chamber needs to have a die-cutting slope, and the oil once entered the oil introduction chamber returns to the gear chamber containing the ring gear without entering the oil hole. There is a problem that it ends up. In the case of die casting, undercutting cannot be performed and an oil return prevention wall cannot be formed, so the amount of oil supplied to the pinion shaft chamber is inevitably reduced.
[0005]
On the other hand, a differential carrier having a structure in which an oil hole to the pinion shaft chamber is enlarged by a casting method using a core is manufactured, and a differential device using this differential carrier has also been proposed (Japanese Utility Model Laid-Open No. 5-94563, JP (Kaihei 11-48805).
However, in the case of a differential carrier manufactured by a casting method, there is a disadvantage that the weight increases due to the use of cast iron and the use of a core increases the number of steps and increases the cost. Further, if the oil hole is too large, there is a problem that the rigidity of the support part supporting the pinion shaft is lowered.
[0006]
Accordingly, an object of the present invention is to lubricate a differential gear that can supply a sufficient amount of oil to the pinion shaft chamber using the flow of oil pumped up by the ring gear even if a die-cast differential carrier is used. To provide a structure.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a pinion having a differential carrier, a differential cover attached to the differential carrier, a pinion shaft chamber of the differential carrier supported by a bearing, and having a pinion gear at one end. A shaft, a differential case that is pivotally supported by the bearing support portion of the differential carrier, and a ring gear that meshes with the pinion gear and is attached to the differential case. In the differential that is raised and introduced into the pinion shaft chamber, an oil introduction chamber that receives the oil pumped up by the ring gear at a position offset from the pinion shaft chamber to the ring gear side on the inner surface of the differential carrier. And extending the lower end of the oil introduction chamber below the top of the pinion shaft chamber In addition, an oblique oil hole that penetrates from the oil introduction chamber to the pinion shaft chamber is provided at the lower end of the oil introduction chamber, and the oil that has entered the oil introduction chamber passes through the inner surface of the oil introduction chamber. Provided is a differential structure lubrication structure characterized by being inclined so as to be gathered toward the surface.
[0008]
Oil accumulated in the space between the differential carrier and the differential cover is pumped up by the ring gear and enters the oil introduction chamber by the centrifugal force. The oil that has entered the oil introduction chamber flows downward along the inclined portion of the inner surface of the oil introduction chamber by gravity, and reaches an oil hole provided in the lower end portion. The oil introduction chamber is laterally offset from the pinion shaft chamber, and the lower end of the oil introduction chamber extends below the top of the pinion shaft chamber, so that a large vertical drop in the oil introduction chamber should be taken. Can do. Since the oil hole is an oblique hole penetrating toward the pinion shaft chamber, the oil rushes through the inner surface of the oil introduction chamber, enters the oil hole, and is supplied to the pinion shaft chamber. Further, since the vertical dimension of the oil introduction chamber can be increased, the oil pumped up by the ring gear can be efficiently received in the oil introduction chamber.
When the differential carrier is made of die-cast, there is a phenomenon that the oil that has entered from the oil introduction chamber returns to the gear chamber side that accommodates the ring gear due to the mold drawing gradient. However, as in the present invention, the vertical dimension of the oil introduction chamber is increased and oil is supplied to the oil hole using the oil flow due to the inclination of the inner surface of the oil introduction chamber. Can be reduced, and a sufficient amount of oil can be supplied to the pinion shaft chamber.
[0009]
According to a second aspect of the present invention, an inclined surface that is inclined downward toward the oil hole is provided at a lower end portion of the oil introduction chamber so as to be a lower end in the vicinity of the outer opening of the oil hole, and the direction of the oil hole Is preferably substantially parallel to the inclined surface.
The oil flowing along the inner surface of the oil introduction chamber is received by the inclined surface of the lower end portion, and the direction of oil flow is changed to flow toward the oil hole. Since the direction of the oil hole is substantially parallel to the inclined surface at the lower end, oil flowing along the inclined surface enters the oil hole without resistance. Therefore, as much oil as possible can be guided to the pinion shaft chamber.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an example of a differential according to the present invention. This differential device is an example of a differential device (rear differential) for a rear wheel of a four-wheel drive vehicle, for example.
This differential device includes a differential carrier 1 formed by aluminum die casting, a differential cover 2 made of sheet metal to be attached to an opening of the differential carrier 1, and bearings 4 and 5 in a pinion shaft chamber 3 formed in the differential carrier 1. A pinion shaft 6 that is rotatably supported via a bearing, a differential case 9 that is pivotally supported via a bearing 8 on a pair of bearing support portions 7 formed integrally with the differential carrier 1, and the like.
[0011]
A flange 10 connected to a propeller shaft (not shown) is fastened to one end of the pinion shaft 6 by a nut 11, and a pinion gear 12 made of a hypoid gear is integrally formed on the other end. An oil seal 13 for preventing oil leakage is provided between the flange 10 and the pinion shaft chamber 3.
[0012]
The pinion gear 12 meshes with a ring gear 15 fixed to the differential case 9 by bolts 14. In the differential case 9, a differential pinion shaft 16 is held in an orthogonal direction, and a differential pinion 17 is pivotally supported on the differential pinion shaft 16. A pair of side gears 18 mesh with the differential pinion 17, and these side gears 18 are coupled to a pair of axles 19 inserted through the differential case 8 so as to be integrally rotatable.
[0013]
Next, a specific structure of the differential carrier 1 will be described with reference to FIGS.
An oil introduction chamber 21 that opens toward the gear chamber 20 surrounded by the differential carrier 1 and the differential cover 2 is located on the inner surface of the differential carrier 1 and offset from the axial center of the pinion shaft chamber 3 toward the ring gear 15. Is provided. As shown in FIG. 5, the oil introduction chamber 21 is formed at a position facing the outer peripheral portion of the ring gear 15 so as to receive the oil pumped up by the ring gear 15.
[0014]
The lower end portion of the oil introduction chamber 21 extends downward from the top of the pinion shaft chamber 3, and the peripheral wall portion 22 of the pinion shaft chamber 3 extends from the oil introduction chamber 21 toward the pinion shaft chamber 3 at this lower end portion. An oblique oil hole 23 is provided therethrough. In this embodiment, the oil hole 23 is inclined toward the axis of the pinion shaft chamber 3. As shown in FIG. 6, the oil hole 23 is formed by drilling so as to penetrate from the outer wall portion 24 of the oil introduction chamber 21 to the peripheral wall portion 22 of the pinion shaft chamber 3. Sealed by a plug 26.
[0015]
An inclined surface 21 a (see FIG. 5) that slopes downward toward the oil hole 23 is provided at the lower end of the oil introduction chamber 21 so as to be the lower end in the vicinity of the outer opening of the oil hole 23. The direction of the oil hole 23 is substantially parallel to the inclined surface 21a. On the upper inner surface of the oil introduction chamber 21, there is provided an inclined surface 21b that is gradually inclined downward toward the front. Further, the innermost surface 21c (see FIG. 6) at the innermost portion of the oil introduction chamber 21 is a substantially vertical surface, and the oil hole 23 is formed in the vicinity of the innermost surface 21c.
[0016]
The oil pumped up by the ring gear 15 as described above enters the oil introduction chamber 21 and is fed into the oil hole 23 along the inclined surfaces 21b and 21a. At this time, since the lower end portion of the oil introduction chamber 21 extends to a position below the top of the pinion shaft chamber 3, the vertical dimension H of the oil introduction chamber 21 can be increased (see FIG. 5). ), The amount of oil entering the oil introduction chamber 21 can be increased. Further, since the drop H of the oil introduction chamber 21 is also increased, the oil flow that flows along the inner surface of the oil introduction chamber 21 can be used to vigorously feed the oil hole 23.
[0017]
Since the differential carrier 1 is made of die-casting, there is a phenomenon that the oil that has entered the oil introduction chamber 21 returns to the gear chamber 20 side due to the die-cutting slope, but as described above, the drop H and the inclined surface 21a. , 21b is used to feed oil into the oil hole 23 by using the oil flow, so that a sufficient amount of oil can be supplied to the pinion shaft chamber 3.
[0018]
Particularly, since the lower surface of the oil introduction chamber 21 is an inclined surface 21a, and the inclined surface 21a and the oil hole 23 are substantially parallel, the oil flowing along the inclined surface 21a enters the oil hole 23 without resistance. Can do. Therefore, a sufficient amount of oil can be supplied to the pinion shaft chamber 3, and the bearings 4, 5 and the oil seal 13 can be efficiently lubricated.
[0019]
Between the bearing 40 of the pinion shaft chamber 3 and the oil seal 13, a return hole 27 (see FIG. 7) for returning the oil that has entered the pinion shaft chamber 3 to the gear chamber 20 is formed. Thus, an oil circulation path is formed from the gear chamber 20 to the oil introduction chamber 21 to the oil hole 23 to the pinion shaft chamber 3 to the return hole 27 to the gear chamber 20. Therefore, the oil in the pinion shaft chamber 3 can be circulated constantly.
[0020]
Of course, the differential of the present invention can be applied not only to the rear differential but also to the front differential.
The shape of the differential carrier, particularly the shape of the oil introduction chamber, is not limited to the above embodiment.
For example, the shape of the lower surface of the oil introduction chamber 21 does not have to be the inclined surface 21a as in the embodiment, and if the inner surface of the oil introduction chamber 21 is inclined so that the oil gathers toward the oil hole 23, The lower surface of the oil introduction chamber may be substantially horizontal.
[0021]
【The invention's effect】
As apparent from the above description, according to the invention of claim 1, the oil that receives the oil pumped up by the ring gear at the position on the inner surface of the differential carrier that is offset from the pinion shaft chamber to the ring gear side. An introduction chamber is provided, and the lower end portion of the oil introduction chamber extends below the top of the pinion shaft chamber, and an oblique oil hole penetrating from the oil introduction chamber toward the pinion shaft chamber is formed at the lower end portion of the oil introduction chamber. Since the oil introduction chamber is slanted so that the oil that has entered the oil introduction chamber gathers toward the oil hole, the flow of oil pumped up by the ring gear even when using a die-cast differential carrier Can be used to supply a sufficient amount of oil to the pinion shaft chamber.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an example of a differential device according to the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a plan view of a differential carrier of the differential device shown in FIG. 1;
4 is a cross-sectional view taken along line BB in FIG.
5 is a right side view of the differential carrier of FIG. 3. FIG.
6 is a cross-sectional view taken along line CC in FIG.
7 is a cross-sectional view taken along line DD of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Differential carrier 2 Differential cover 3 Pinion shaft chamber 4,5 Bearing 6 Pinion shaft 7 Bearing support part 9 Differential case 12 Pinion gear 13 Oil seal 15 Ring gear 21 Oil introduction chamber 23 Oil hole 21a, 21b Inclined surface

Claims (2)

A differential carrier, a differential cover attached to the differential carrier, a pinion shaft supported by a pinion shaft chamber of the differential carrier via a bearing and having a pinion gear at one end, and a differential case pivotally supported by a bearing support portion of the differential carrier And a differential gear that meshes with the pinion gear and is attached to the differential case, and the oil accumulated in the space between the differential carrier and the differential cover is scraped up by the ring gear and introduced into the pinion shaft chamber. ,
An oil introduction chamber for receiving the oil pumped up by the ring gear is provided on the inner surface of the differential carrier at a position offset from the pinion shaft chamber to the ring gear side,
While extending the lower end of the oil introduction chamber from below the top of the pinion shaft chamber,
An oblique oil hole that penetrates from the oil introduction chamber to the pinion shaft chamber is provided at the lower end of the oil introduction chamber,
A lubricating structure for a differential gear, wherein an inner surface of the oil introduction chamber is inclined so that oil entering the oil introduction chamber gathers toward the oil hole. An inclined surface that is inclined downward toward the oil hole is provided at the lower end of the oil introduction chamber so as to be a lower end in the vicinity of the outer opening of the oil hole.
2. The lubricating structure for a differential gear according to claim 1, wherein the direction of the oil hole is substantially parallel to the inclined surface.

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