JPH0754962A - Planetary gearing mechanism - Google Patents

Abstract

PURPOSE:To heighten the impact fatigue strength of each pinion by forming a reinforcing rib at the tooth bottom at each end of the pinion, and forming a chamfer to avoid interference with the reinforcing rib on a sun gear and internal gear to be coupled by the pinion. CONSTITUTION:A planetary gearing mechanism 35 is installed, for example, in a differential case 21 of a rear differential 7. An internal gear 37 is formed in the differential case 21, and a sun gear 39 is formed on a lefthand hub 31. Pinions 41, 43 on the inside and outside to couple the two gears 37, 39 are borne by shafts 45, 47 on the left and right pinion carriers 51, 53 through bushings 49. Therein, reinforcing ribs 55 to couple the teeth are formed at both ends of the pinions 41, 43, and the gears 37, 39 are provided with chamfers 59, 61 so that interference with the ribs 55 is avoided. This enhances the impact fatigue strength of the pinions and allows the gear thickness to be lessened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary gear mechanism.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 2-107847 discloses a differential device 201 as shown in FIG.
This is equipped with a multi-disc clutch 203 for limiting the differential, and the differential mechanism 205 is of a planetary gear type.

[0003]

The planetary gear type differential mechanism 205 has the advantages that it can be downsized in the axial direction as compared with, for example, a bevel gear type and that the differential limiting device can be easily arranged between the axles. is there. However, the pinion gear 20
No. 7,209 has a small diameter and a small module, which is disadvantageous in terms of strength, and is easily damaged due to insufficient impact fatigue strength in a starting durability test in which a large force is rapidly and repeatedly applied, such as when the vehicle starts.

Therefore, an object of the present invention is to provide a planetary gear mechanism in which the pinion gear has a large impact fatigue strength.

[0005]

The planetary gear mechanism of the present invention comprises an internal gear, a sun gear, and a pinion gear that connects them, and a reinforcing rib is provided at the bottom of the tooth at the end of the pinion gear. The null gear and the sun gear are characterized by being chamfered to avoid interference with the reinforcing ribs.

[0006]

The reinforcing rib for connecting the adjacent teeth is formed on the tooth bottom of the end of the pinion gear, and the internal gear is chamfered to avoid interference with the reinforcing rib. By providing the reinforcing ribs, cracks that are likely to occur at the tooth bases are effectively prevented, so that the pinion gear is provided with sufficient impact fatigue strength. Further, since the strength is improved, it is not necessary to increase the tooth thickness of the pinion gear in order to make the module large, and the pinion gear can have the same tooth thickness as the internal gear and the sun gear.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment will be described with reference to FIGS. FIG. 1 shows a differential device using this embodiment as a differential mechanism, and FIG. 8 shows a vehicle power system using this differential device. The left and right directions are this vehicle and Fig. 1,
The left and right directions in FIGS. 3 and 5. Members without reference numerals are not shown.

As shown in FIG. 8, this power system includes an engine 1, a transmission 3, a propeller shaft 5, a rear differential 7 (a differential device shown in FIG. 1 arranged between rear wheels), rear axles 9, 11 and left and right rear wheels. 13, 15 and left and right front wheels 17, 19 and the like.

The differential case 21 of the rear differential 7 is arranged in the differential carrier 23, and the ring gear 25 is fixed to the differential case 21. The ring gear 25 meshes with the drive pinion gear 27, and the drive pinion gear 27
Is integrally formed with a drive pinion shaft 29 connected to the propeller shaft 5 side. In this way, the driving force of the engine 1 rotationally drives the differential case 21 via the transmission 3 and the propeller shaft 5.

As shown in FIG. 1, left and right hubs 31 and 33 are arranged inside the differential case 21.
Reference numeral 33 is splined to the left and right rear axles 9 and 11, respectively.

A differential mechanism 35 (double pinion planetary gear mechanism) is arranged in the differential case 21.
The internal gear 37 is formed on the differential case 21, and the sun gear 39 is formed on the left hub 31. The outer and inner pinion gears 41 and 43 are provided on the left and right pinion carriers 51 and 53 via the bushes 49 by the shaft portions 45 and 47.
Is supported by.

As in the pinion gear 41 shown in FIGS. 2 and 3, reinforcing ribs 55 are formed at the bottoms of the teeth to connect the teeth to each other at both ends of each of the pinion gears 41 and 43. As shown in FIG. 3, the tip of the reinforcing rib 55 has a pitch circle of 5 so that the meshing of the pinion gears 41 and 43 is not supported.
I try not to exceed 7. Also, internal gear 3
7 and the sun gear 39 are chamfered 59 and 61 so as not to interfere with the reinforcing rib 55. In particular, the chamfer 61 on the right side is moved to the left side in consideration of a margin for movement so as not to interfere when the pinion gears 41 and 43 move to the left as described later. The pinion gears 41, 43 are formed by rolling or press forming with the reinforcing rib 55.

The pinion gears 41 and 43 are attached to the right pinion carrier 53 through the bushes 49 while the shaft portions 45 and 47 are fitted to the internal gear 37 and the sun gear 39, respectively. Thereafter, as shown in FIGS. 4 and 5, the left pinion carrier 51 is fixed to the right pinion carrier 53 with bolts 65 while aligning with the pin 63. As shown in FIG. 1, the right pinion carrier 53 is the right hub 33.
Splined to.

Since the reinforcing ribs 55 are provided, the impact fatigue strength of the pinion gears 41 and 43 is significantly improved.
It effectively prevents cracks that tend to occur at the tooth bottom when the vehicle repeatedly starts suddenly. Further, since the strength is thus strengthened, it is not necessary to increase the tooth thickness of the pinion gears 41 and 43, and the tooth thickness can be made the same as that of the internal gear 37 and the sun gear 39.

The driving force of the engine 1 is transmitted from the differential case 21 (internal gear 37) through the pinion gears 41 and 43 to the sun gear 39 (hub 31) and the pinion carrier 53.
(Hub 33) and sent to the left and right rear wheels 13, 15. If a drive resistance difference occurs between the rear wheels, the pinion gear 4
The driving force of the engine 1 is differentially distributed to the left and right sides due to the rotation and revolution of 1, 43.

In this way, the differential mechanism 35 is constructed.

A multi-plate type main clutch 69 is arranged between the cylindrical portion 67 of the pinion carrier 51 and the hub 31. A washer 71 is arranged on the left side of the main clutch 69, and the claw 73 is engaged with the lubricating hole 75 of the differential case 21. A cam ring 77 is arranged on the right side of the pinion carrier 53, and a ball cam 79 is arranged between them.
Is provided. A bearing 83 and a washer 85 that receive the cam reaction force of the ball cam 79 are disposed between the cam ring 77 and the right side wall 81 of the differential case 21.

A multi-plate pilot clutch 87 is arranged between the differential case 21 and the cam ring 77.
An armature 89 is arranged on the left side of the armature 89 and is positioned by a retaining ring 91. Right boss portion 9 of the differential case 21
A ring-shaped electromagnet 97 is supported by 3 via bearings 95, 95, and is prevented from rotating by the differential carrier 23 via a supporting member. On the right side wall 81, a stainless steel ring 99 that prevents short circuit of the magnetic flux of the electromagnet 97 and leads to the armature 89 is arranged.

When the electromagnet 97 attracts the armature 89 and the pilot clutch 87 is engaged, the differential torque of the differential mechanism 35 is applied to the ball cam 79, and the cam thrust force moves the pinion carriers 51 and 53 to the left. The main clutch 69 is pressed, and the differential force is limited by the coupling force of the clutches 69 and 87. As described above, the internal gear 37 and the sun gear 39 have the right chamfer 61 moved to the left, so that the reinforcing rib 5 is engaged when the main clutch 69 is engaged.
No interference with 5.

A pilot clutch 87 is provided by an electromagnet 97.
By adjusting the slip of the vehicle and moderately reducing the differential limiting force, the vehicle can make smooth and stable turns. In addition, if the differential limiting force is increased or the differential is locked, straight running stability is improved, and even if one of the rear wheels runs idle on a bad road, a large driving force is applied to the other side due to the differential limiting force. It is sent to the wheel and the rough road running performance is improved. When the pilot clutch 87 is released, the cam thrust force of the ball cam 79 disappears and the main clutch 69
Is also released and the differential becomes free.

In the case of the double pinion planetary gear mechanism, the reinforcing rib may be provided only on one of the pinion gears, unlike the embodiment. FIGS. 6 and 7 show such an example. In the left half of FIGS. 6 and 7, the internal gear 101 meshes with the pinion gear 105 with the reinforcing rib 103, and the sun gear 107 is the normal half without the reinforcing rib. In the right half, the internal gear 111 meshes with the normal pinion gear 109 and the sun gear 113 has the reinforcing rib 103.
The example shown in FIG.

In the example of the left half part, a normal pinion gear 109 is used.
The sun gear 107 meshed with can be disengaged independently. In the example of the right half, the sun gear 113 and each pinion gear 105,
109 is engaged with and disengaged from the internal gear 111.

Further, the planetary gear mechanism of the present invention is not limited to the double pinion, and is particularly effective for triple pinions or more in which the pinion gear has a smaller diameter. Etc. is advantageous. Further, the reinforcing rib may be provided only on one side of the pinion gear.

[0024]

According to the planetary gear mechanism of the present invention, a reinforcing rib for connecting teeth is provided at the end of the pinion gear, and a chamfer is provided on the internal gear and the sun gear so as not to interfere with the reinforcing rib. Fatigue strength is greatly improved, and the pinion gear can have the same tooth thickness as the internal gear and sun gear.

[Brief description of drawings]

FIG. 1 is a sectional view of a differential device using this embodiment for a differential mechanism.

FIG. 2 is a side view of a main portion of a pinion gear.

FIG. 3 is a sectional view of a main part of a pinion gear.

FIG. 4 is a side view of a pinion carrier assembly.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is a schematic view of the present invention showing another example of a combination of pinion gears.

7 is a cross-sectional view of a combination example corresponding to FIG.

8 is a skeleton mechanism diagram showing a power system of a vehicle using the differential device of FIG.

FIG. 9 is a sectional view of a conventional example.

[Explanation of symbols]

 35 Differential Mechanism (Planetary Gear Mechanism) 37 Internal Gear 39, 107, 113 Sun Gear 41, 43, 105 Pinion Gear 55, 103 Reinforcing Rib 59, 61 Chamfer

Claims (1)

[Claims] 1. An internal gear, a sun gear, and a pinion gear that connects these gears to each other. A reinforcing rib is provided at a tooth bottom of an end of the pinion gear, and the internal gear and the sun gear interfere with each other. A planetary gear mechanism characterized by being provided with chamfers to avoid.