JPH04321848A - Planetary gear mechanism - Google Patents

Abstract

PURPOSE:To prevent abrasion and seizure between a pinion gear and a pinion carrier by setting the space between one end portion of a pinion gear and a pinion carrier relatively large so that a shaft portion and the casing side come into contact with each other earlier than the pinion gear and the pinion carrier do so. CONSTITUTION:When a differential case 25 is rotated by the driving force from an engine, the rotation is distributed to a sun gear and a pinion carrier 53 through a pinion gear 39 and transmitted to the right and left rear wheels through each hub. When a driving resistance difference is generated between the rear wheels, the sun gear and the pinion carrier 53 are differentially rotated by the rotation and revolution of the pinion gear 39. In this case, when the space between the right pinion carrier 53 and a washer 5 7 is (b), the space between the left end of the pinion gear 39 and the left pinion carrier 51 is (c), and the space between the end portion of the left shaft portion 47 and the washer 57 is (e), they are set in such a manner as to satisfy the following expression: b+e<c.

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

[Prior Art] U. S. Patent No. 2178613 states “DIFFERENTIAL MECHANISM
” is written. This is a planetary gear mechanism in which an internal gear and a sun gear are connected by a pinion gear, and is used in transmissions and differential devices as in the above publication.

0003

In the planetary gear mechanism disclosed in the above-mentioned publication, the planetary gear mechanism is rotatably supported on the pinion shaft. Therefore, when the pinion gear moves in the axial direction due to vibration or the like (or thrust force if the pinion gear is a helical gear), the end portion of the pinion gear rotates while contacting the pinion carrier. Burrs are likely to remain on the end of the pinion gear during gear cutting, and these burrs cause wear between the pinion gear and the pinion carrier. Furthermore, since this part is surrounded by internal gears and held between pinion carriers on both sides, it is difficult to lubricate it and seizure is likely to occur. Even if an attempt is made to reduce friction by smoothing the surface of this contact area of the pinion carrier, the pinion carrier is held together by a connecting part provided on one side of the carrier, and this connecting part makes machinability difficult. Bad,
The cost will be high. Therefore, a washer device is required instead of a finish.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a planetary gear mechanism in which the end of the pinion gear does not come into contact with the pinion carrier.

[0005]

[Means for Solving the Problems] The planetary gear mechanism of the present invention includes an internal gear, a pinion gear that meshes with the internal gear and is integrally provided with a shaft portion at both ends, a sun gear that meshes with the pinion gear, and a pinion gear that meshes with the pinion gear. A pair of pinion carriers arranged on both axial sides of the pinion gear, rotatably and axially movably supporting the shaft portion, and integrally connected to each other, and a casing that houses them, It is characterized in that the distance between the pinion carrier and the pinion carrier is larger than the sum of the distance between the shaft end on one side and the casing side and the distance between the pinion carrier on the other axial side and the casing side.

[0006]

[Operation] This will be explained with reference to FIG. The left and right directions are the left and right directions in FIG.

The pinion gear 201 has left and right shaft portions 203,
Left and right pinion carriers 207, 209 via 205
It is rotatably supported. Each carrier 207, 20
9 is fixed integrally.

The distance between the left carrier 207 and the casing 211 is a, the distance between the right carrier 209 and the casing 211 is b, the distance between the left end of the gear 201 and the left carrier 207 is c, and the distance between the right end of the gear 201 and the right The distance between the carrier 209 and the end of the left shaft portion 203 is d, and the distance between the end of the left shaft portion 203 and the casing 211 is
e, the end of the right shaft portion 205 and the casing 21
When the distance from 1 is f, b+e<c, as shown in Figure 4.
It is set as a+f<d.

Here, c and d are the distances between one axial end of the pinion gear and the pinion carrier, e and f are the distances between the one shaft end and the casing, and a and b
is the distance between the pinion carrier on the other axial side and the casing side. Note that when considering the contact state on the left side, the left side is assumed to be one side in the axial direction, and when considering the contact state on the right side, the right side is assumed to be one side in the axial direction.

Now, let us consider the case where the distance c and the distance d are each the narrowest.

The carrier 207 has the minimum distance c.
, 209 move to the right and the carrier 209 comes into contact with the casing 211, and the pinion gear 201 moves to the left and the shaft portion 203 comes into contact with the casing 211. At this time, the distance c becomes narrower by the distance b due to the movement of the carriers 207 and 209, and becomes narrower by the distance e due to the movement of the gear 201. As above, the interval c is the sum of these (b
+e) Since it is larger, gear 201 and carrier 2
There is no contact with 07.

The distance d is the smallest at the carrier 207
, 209 move to the left and the carrier 207 comes into contact with the casing 211, and the pinion gear 201 moves to the right and the shaft portion 205 comes into contact with the casing 211. At this time, the distance d becomes narrower by the distance a due to the movement of the carriers 207 and 209, and becomes narrower by the distance f due to the movement of the gear 201. As above, the interval d is the sum of these (a
+f) Since it is larger than gear 201 and carrier 2.
There is no contact with 09.

[0013] Therefore, in any case, the end face of pinion gear 201 does not come into contact with pinion carriers 207, 209, and contact always occurs between shaft portions 203, 205 and casing 211.

It is easy to machine this contact part of the casing 211 smoothly, and since this part is not closed, lubrication is easy. Therefore, increases in costs due to machining of difficult-to-process locations and use of washers are prevented, and seizure does not occur.

[0015]

[Embodiment] One embodiment will be explained with reference to FIGS. 1 to 3. FIG. 1 shows this embodiment used as a differential device, and FIG. 3 shows the power system of a vehicle using this differential device. Below, the left and right directions are for this vehicle and Figure 1.
, and the left and right directions in FIG. 2, and the upper part of FIGS. 1 and 2 corresponds to the front of this vehicle (the upper part of FIG. 3).

First, the configuration of this power system will be explained with reference to FIG.

This power system includes an engine 1, a transmission 3, left and right front wheels 5, 7, a propeller shaft 9, and a rear differential 11 (the differential device shown in FIG. 1 used on the rear wheel side).
, rear axles 13, 15, left and right rear wheels 17, 19, etc.

Next, the rear differential 11 will be explained.

As shown in FIG. 3, a differential case 21 (casing) of the rear differential 11 is rotatably supported within a differential carrier 23. As shown in FIG. The differential case 21 has a ring gear 2
5 is fixed, and this ring gear 25 meshes with a drive pinion gear 27. The drive pinion gear 27 is integrally formed at the rear end of the drive pinion shaft 29, and the drive pinion shaft 29 is connected to the propeller shaft 9 side. In this way, the differential case 21 is rotationally driven by the driving force from the engine 1.

As shown in FIG. 1, left and right hubs 31 and 33 are coaxially arranged inside the differential case 21. The left hub 31 is splined to the left rear axle 13 and the right hub 33 is splined to the right rear axle 15. The hubs 31 and 33 can be moved slightly left and right together with the respective axles 13 and 15 or by sliding on these spline portions.

The differential case 21 is provided with an internal gear 35, an outer pinion gear 37, an inner pinion gear 39, and a sun gear 41 that mesh in this order. The internal gear 35 is formed on the differential case 21, and the sun gear 41 is formed on the left hub 31.

Each pinion gear 37, 39 is rotatably and axially movably supported by left and right pinion carriers 51, 53 via shaft portions 43, 45, 47, 49 integrally formed at both ends, respectively. The right carrier 53 is integrally formed with the right hub 33. Furthermore, the left and right carriers 51 and 53 are welded together.

The pinion gear 37 has a slightly smaller diameter than the left shaft portion 43 and has a larger diameter than the right shaft portion 45, and the pinion gear 39 has a slightly larger diameter than the right shaft portion 47 and has a slightly larger diameter than the right shaft portion 49. It has a small diameter. Therefore, after welding the pinion carriers 51 and 53, the outer pinion gear 37 is inserted from the left side, and the inner pinion gear 39 is inserted from the right side.
They can be assembled to carriers 51 and 53, respectively.

A washer 55 is arranged between the differential case 21 and the left carrier 51, and a washer 57 is arranged between the differential case 21 and the right carrier 53.

The differential case 21 has through holes 59, 60, 6.
1 are provided, and oil sealed in the differential carrier 23 flows in and out from these through holes 59, 60, and 61, and lubricates the meshing parts and sliding parts of the gears in the differential case 21.

When the differential case 21 (internal gear 35) rotates due to the driving force from the engine 1, this rotation is divided between the sun gear 41 (hub 31) and the pinion carrier 53 (hub 33) via the pinion gears 37 and 39. The power is transmitted to the left and right rear wheels 17 and 19 via the hubs 31 and 33. Furthermore, when a difference in drive resistance occurs between the rear wheels, the sun gear 41 and the pinion carrier 53 differentially rotate due to the rotation and revolution of the pinion gears 37 and 39, and the driving force of the engine 1 is differentially applied to the rear wheels 17 and 19. distributed.

On the other hand, between the left shaft portions 43, 47 of the pinion gears 37, 39 and the carrier 51, and the right shaft portion 45
, 49 and the carrier 53, rotational resistance occurs due to friction during torque transmission. This rotational resistance is large due to the large diameter of the shaft portions 43, 49, and this large resistance brakes the rotation and revolution of the pinion gears 37, 39.
Differential limiting force is obtained. The greater the driving force of the engine, the greater the frictional resistance generated in the shaft portions 43, 45, 47, 49, and the greater the differential limiting force.

FIG. 2 is a sectional view depicting the inner pinion gear 39 and its surrounding members.

Note that in FIG. 2, c and d represent one end of the pinion gear 39 in the axial direction and the pinion carriers 51, 5.
3, e and f are the distances between the ends of the shaft portions 47, 49 on one side and the washers 55, 57 (casing side), and a and b are the distances between the pinion caps on the other side in the axial direction. Riya 53,
51 and the washers 57, 55 (casing side). When considering the contact state on the left side, the left side is assumed to be one side in the axial direction, and when considering the contact state on the right side, the right side is assumed to be one side in the axial direction.

The distance between the left carrier 51 and the washer 55 is a, the distance between the right carrier 53 and the washer 57 is b,
The distance between the left end of the pinion gear 39 and the carrier 51 is c,
The distance between the right end of the pinion gear 39 and the carrier 53 is d,
When the distance between the end of the left shaft portion 47 and the washer 55 is e, and the distance between the end of the right shaft portion 49 and the washer 57 is f, b+e<c as shown in FIG.

When the carriers 51, 53 move to the right and the carrier 53 comes into contact with the washer 57, and the pinion gear 39 moves to the left and the shaft portion 47 comes into contact with the washer 55, the gap c becomes the narrowest. At this time, the distance c is the carrier 51
, 53, the distance b is narrowed by the movement of pinion gear 3.
9 becomes narrower by the distance e. As shown in FIG. 2, since the distance c is larger than the sum of these (b+e), the left end of the pinion gear 39 and the carrier 51 do not come into contact with each other.

Therefore, in any case, the pinion gear 39 and the carrier 51 do not come into contact with each other, and the contact always occurs between the shaft portion 47 and the washer 55.

Further, as described above, since the pinion gear 39 has a smaller diameter than the shaft portion 49, even if the pinion gear 39 moves to the right, the pinion gear 39 and the carrier 53 will not come into contact with each other, and the contact will be made with the shaft portion 49. and the washer 57.

Note that the shaft portion 49 may have a smaller diameter than the pinion gear 39. In this case, a+
If f<d, the pinion gear 39 and carrier 53 will never come into contact with each other under any circumstances, and contact will always occur between the shaft portion 49 and the washer 57, as in the case of the shaft portion 47 side described above.

The outer pinion gear 37 is constructed in the same way as the inner pinion gear 39 (however, the left and right sides are opposite).
The pinion gear 37 and the carrier 53 do not contact each other, but the shaft 45 and the washer 57 contact each other. On the left side, the shaft portion 43 contacts the washer 55 .

In this manner, since the pinion gears 37, 39 and the pinion carriers 51, 53 do not come into contact with each other, wear and seizure due to burrs do not occur. Therefore, deburring and precision machining of the insides of the carriers 51, 53 are not necessary, and washers disposed between the pinion gears 37, 39 and the carriers 51, 53 are also not required, reducing costs. Moreover, the casing 21 (washers 55, 57) and the shaft parts 43, 45,
Oil easily circulates in the contact parts with 47 and 49, and abnormal wear and seizure do not occur.

[0037] In this way, the rear differential 11 is constructed.

The vehicle shown in FIG. 3 has rear wheels 17 and 19 on a rough road.
Even if one of the wheels is in a idling state, the driving force of the engine 1 is sent to the other rear wheel by the differential limiting force of the rear differential 11, and the ability to travel on rough roads is maintained. When starting (accelerating), the differential between the rear wheels is limited by the differential limiting force of the rear differential 11.
Improves straight-line stability. The effect of improving straight-line stability becomes greater as the driving force of the engine increases. Furthermore, when turning without much acceleration, the differential limiting force of the rear differential 11 is small, so that smooth turning can be achieved.

Note that in this embodiment, the internal gear 35
and the sun gear 41 are connected by two pinion gears 37 and 39 (double pinion), but the number of pinion gears may be one or three or more. Alternatively, the shaft portion may be brought into direct contact with the casing without using the washers 55, 57.

[0040] When both shaft portions have a small diameter relative to the pinion gear, both shaft portions may be configured so as to come into contact with the casing side.

The planetary gear mechanism of the present invention may be used, for example, as a transmission mechanism in addition to the differential device as in the embodiment.

[0042]

Effects of the Invention The planetary gear mechanism of the present invention allows the distance between one end of the pinion gear in the axial direction and the pinion carrier to be adjusted to the distance between the end of the shaft on one side and the casing side and the pinion carrier on the other side in the axial direction. By making the distance larger than the sum of the distances from the casing side, the shaft portion and the casing side come into contact earlier than the pinion gear and pinion carrier. Therefore, wear and seizure between the pinion gear and the pinion carrier are prevented, and there is no need for deburring the pinion gear, precision machining of the pinion carrier, washer between the pinion gear and the carrier, etc., and costs are reduced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a differential device using one embodiment.

FIG. 2 is a sectional view of the pinion gear 39 and its peripheral members in this embodiment.

3 is a skeleton mechanism diagram showing a power system of a vehicle using the differential device of FIG. 1. FIG.

FIG. 4 is a sectional view for explaining the operation and effects of the present invention.

[Explanation of symbols]

11 Rear differential (planetary gear mechanism) 21 Differential case (casing) 35 Internal gears 37, 39 Pinion gear 41 Sun gear 43, 45, 47, 49 Shaft portion 51, 63 Pinion carrier

Claims (1)

[Claims] [Claim 1] An internal gear, a pinion gear that meshes with the pinion gear and has shaft parts integrally provided at both ends, a sun gear that meshes with the pinion gear, and a sun gear that is arranged on both sides of the pinion gear in the axial direction and whose shaft parts are rotatable. and a pair of pinion carriers that are supported so as to be movable in the axial direction and are integrally connected to each other, and a casing that houses them, and the distance between the one axial end of the pinion gear and the pinion carrier is determined by the one shaft portion. A planetary gear mechanism characterized in that the distance between the end and the casing side is greater than the sum of the distance between the pinion carrier on the other axial side and the casing side.