JPH09303533A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a seizure between the sliding surface of a pinion shaft and pinion gears, by suppressing the generation of an abnormal rotation difference between both members. SOLUTION: A differential case 1 having a ring gear 11 for input; pinion gears 12 and 13 pivoted in the differential case 1; and a pair of side gears 16 and 17 engaging with the pinion gears installed to output shafts 2 and 3; are provided, and especially, a pinion shaft to pivot the pinion gears 12 and 13 is divided into short pinion shafts 14 and 15 between both pinion gears, and the divided short pinion shafts 14 and 15 are provided rotatable relatively to the differential case main body 7 and the pinion gears 12 and 13 respectively, and as a result, the short pinion shafts are made rotated following the pinion gears in the rotating condition of the pinion gears.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential device provided in a power transmission system of an automobile or the like, that is, a differential mechanism receives a rotational force from an input side and the differential mechanism branches the rotational force. Also, the present invention relates to a differential device configured to allow the rotation difference and transmit the difference to each output shaft side.

[0002]

2. Description of the Related Art In a power transmission system of an automobile or the like, a differential is provided in order to split a rotational force from an input side into left and right wheels or front and rear wheels and absorb a rotational difference between inner and outer wheels or front and rear wheels generated when turning a vehicle body. Equipped with equipment. For example, as shown in FIG. 5, this differential device receives a rotational force from the input side by a differential case 101 having an input ring gear 100. A pinion gear 103 is pivotally supported in the differential case via a pinion shaft 102. This pinion gear includes a pair of side gears 104, 1
The output shafts 106 and 107 that rotate integrally with the pair of side gears are allowed to rotate relative to each other, and the rotation can be branched and transmitted.

Here, the pinion gear 10 in the differential case
3 is a pair of side gears 104, 105 meshing with this.
When it receives an equal rotational load from the output shafts 106 and 107 on the side, it revolves only.
When a different rotational load is applied from the 4, 105 side, the pair of side gears 10 rotate about the pinion shaft 102.
The output shafts 106, 10 while allowing the rotation difference on the 4, 105 side.
The rotation is branched to the 7 side and transmitted. In this way, the pinion gear 103 rotates about the pinion shaft 102, and the rear surface of the pinion gear 103 is in sliding contact with the differential case 101. Therefore, an appropriate amount of oil contained in the differential case 101 is splashed and supplied to the sliding contact surfaces of the pinion gear 103, the pinion shaft 102, and the differential case 101, whereby the sliding contact surfaces are lubricated and cooled. It is being appreciated.

By the way, the pinion shaft 102 shown in FIG. 5 is inserted into a through hole 108 formed in the differential case 101, and one end of the pinion shaft 102 is provided with a lock pin 109.
It is fixed at 01 so that it cannot be removed. Incidentally, JP-A-7-9
Similarly, Japanese Patent No. 1519 discloses a structure in which one end of a pinion shaft is fitted and inserted in a differential case, and the one end is fixed to the differential case by a pin.

Further, in Japanese Patent Laid-Open No. 2-92734,
A thrust block bulged at the inner end of the pinion shaft is used to receive the thrust force that acts between the left and right side gears when the clutch disc, which is a differential limiting mechanism, is driven by this thrust block. The displacement of the ring gear on the differential case due to
A technique for preventing a tooth contact error is disclosed. The thrust block here is sandwiched between the left and right side gears,
Rotation is restricted. That is, in any of the above-mentioned conventional techniques, the shaft supporting the pinion gear is kept non-rotating.

[0006]

By the way, when one wheel of a vehicle faces a low μ road, that is, on a snowy road or a sandy road, the left and right side gears of the differential gear are subjected to different rotational loads. The pinion gear revolves together with the differential case in order to absorb the abnormal rotation difference of the wheels.
It will rotate rapidly. In this case, since the pinion gear rotates at high speed with respect to the pinion shaft fixed to the differential case, seizure may occur between the sliding contact surfaces of the two. Once seizure occurs, the rotational force from the left and right side gears acts on the lock pin 109 via the pinion shaft and breaks the lock pin 109. Moreover, if this state is entered, the pinion shaft rotating together with the differential case 101 may come out of the through hole 108 of the differential case due to the centrifugal force.

As described above, in order to prevent the pinion gear from rotating at a high speed with respect to the pinion shaft and causing seizure between the sliding contact surfaces, for example, the surface of the pinion shaft facing the pinion gear is surface-treated, or the pinion gear is treated. The shaft material is also manufactured as a low friction material. However, these measures for reducing the frictional resistance are not sufficient solutions, and in particular, when the amount of lubricating oil is insufficient, the rate of occurrence of seizure is further increased. An object of the present invention is to provide a differential device capable of preventing seizure on a sliding contact surface between the pinion shaft and the pinion gear by suppressing an abnormal rotation difference from occurring.

[0008]

In order to achieve the above object, the present invention provides a differential case having an input ring gear, a pair of pinion gears pivotally supported in the differential case, and an output shaft mounted on the differential case. A differential device including a pair of pinion gears and a pair of side gears that mesh with each other, wherein a pinion shaft pivotally supporting the pair of pinion gears is divided into two short pinion shafts between the two pinion gears, and the two short pinions are provided. The pinion shaft is rotatable relative to the differential case and the pinion gear.

According to a second aspect of the present invention, in the differential device according to the first aspect, the differential case is provided with a stopper for preventing the short pinion shaft from falling out of the differential case.

According to a third aspect of the present invention, in the differential device according to the first aspect, a protrusion is formed on a side surface of the short pinion shaft to prevent the short pinion shaft from falling out of the differential case. Characterize.

According to a fourth aspect of the present invention, in the differential device according to the first aspect, a common hollow sleeve is rotatably fitted on the outer circumferences of the opposing portions of the two short pinion shafts.

[0012] The invention of claim 5 is defined by claims 1 to 3.
In the differential device described in (1) above, hollow sleeves are rotatably fitted to the outer circumferences of the facing portions of the both short pinion shafts, respectively, and the outer circumferences of the hollow sleeves are slidably disposed between the facing surfaces of the side gears. Is characterized by.

[0013]

1 shows a differential device to which the present invention is applied. This differential device is arranged in a power transmission system of a vehicle (not shown), receives the rotational force from the input side by the differential case 1, and outputs the branched rotational force while allowing the rotational difference between the inner and outer wheels generated when the vehicle body turns. It is transmitted to the left and right drive wheels (not shown) via the shafts 2 and 3.

This differential device is provided with a housing 4 supported on the vehicle body side, and contains a predetermined amount of lubricating oil therein. The housing 4 accommodates the differential case 1 therein and pivotally supports the left and right cylindrical pivot portions 5 of the differential case 1 via tapered roller bearings 6. The differential case 1 includes a case body 7 having a container shape and an annular flange 8 protruding from a part of an outer peripheral wall of the case body 7.
A ring gear 11 is fixed to the annular flange 8 by bolts, and a pinion gear 10 on an input shaft 9 connected to a peller shaft (not shown) is meshed with the ring gear 11. Therefore, the differential case 1 supported by the taper roller bearing 6 receives the rotation of the input shaft 9 and rotates about the rotation center line L.

Inside the case body 7, a pair of pinion gears 12 and 13 are pivotally supported via respective short pinion shafts 14 and 15, and a rotation center line L is provided between the pinion gears 12 and 13.
A pair of side gears 16 and 17 that rotate around is meshed with each other. The output shafts 2 and 3 are integrally connected to the side gears 16 and 17. The output shafts 2 and 3 are left and right cylindrical pivot portions 5
Is relatively rotatably fitted into the drive shaft, and each outer end of the output shaft is connected to a drive wheel (not shown).

The pinion gears 12 and 13 are rotatably supported by the short pinion shafts 14 and 15, respectively. These short pinion shafts 14 and 15 are arranged in the direction orthogonal to the rotation center line L, and the short pinion shaft 1
4, 15 are arranged on the same pin center line L1. Inner end portions of the two short pinion shafts 14 and 15 that face each other maintain a small gap in which they can rotate relative to each other, and their displacements in the opposite direction are restricted.

Here, one of the short pinion shafts 15 is rotatably fitted in the recessed hole 18 of the case body 7, and the bottom of the recessed hole 18 prevents the short pinion shaft 15 from receiving a centrifugal force from protruding. . The other short pinion shaft 14 is rotatably fitted in the through hole 19 of the case body 7. Moreover, a stopper lid 20 that covers the through hole 19 is fixed to the case body 7 with a plurality of bolts 21. The stopper lid 20 prevents the short pinion shaft 14 that receives centrifugal force from protruding from the through hole 19. As shown in FIG. 2, a recess 24 for avoiding interference with the stopper lid 20 and the plurality of bolts 21 is formed in a part of the inner peripheral portion of the ring gear 11.

Here, a common hollow sleeve 22 is rotatably fitted on the outer peripheral surfaces of the portions of the short pinion shafts 14 and 15 which face each other. The hollow sleeve 22 rotatably connects mutually facing portions of the short pinion shafts 14 and 15 so as to be rotatable relative to each other, and restricts the deviation of the short pinion shafts 14 and 15 from the pin center line L1.
The length A of the hollow sleeve 22 has a length close to the distance between the pair of pinion gears 12 and 13, and thereby the displacement of the hollow sleeve 22 in the pin center line L1 direction is restricted.

When assembling the short pinion shaft 15, the hollow sleeve 22 is externally fitted and the tips are fitted into the pinion gear 13 and the bottom of the recessed hole 18, and the short pinion shaft 14 is inserted into the through hole. It is abutted on the tip of the short pinion shaft 15 via 19 and the pinion gear 12, and is fitted into the hollow sleeve 22. It is assumed that the differential device having such a structure is driven as the vehicle (not shown) travels.

During normal traveling, the rotational force from the input shaft 9 side is decelerated and applied to the differential case 1, and the pair of pinion gears 12 and 13 in the case body 7 only revolves when traveling straight, and when the vehicle body turns, the inner and outer wheels rotate. In order to absorb the rotation difference, it revolves around and rotates about the pin center line L1. On this occasion,
The pair of pinion gears 12, 13 is a short pinion shaft 1
They rotate in the opposite directions around 4, 15 and absorb the difference in rotation. On the other hand, when one wheel of the vehicle faces a low μ road, the left and right side gears 16 and 17 are subjected to significantly different rotational loads. In this case, the pinion gears 12 and 13 revolve rapidly and rotate rapidly to rotate the short pinion shafts 14 and 15 together, and the pair of pinion shafts 14 and 15 also face the concave hole 18, the through hole 19, and the hollow sleeve 22. To rotate.

In this way, one wheel faces the low μ road, and a large rotational difference occurs between the left and right wheels, so that the pair of pinion gears 12,
Even if 13 rotates at high speed, the pair of short pinion shafts 14 and 15 rotate together. Therefore, even if these pinion gears rotate at high speed, the relative rotation with respect to the short pinion shaft is kept relatively small, and therefore seizure between the pinion gear and the short pinion shaft can be reliably prevented from occurring. While the differential device is being driven, both short pinion shafts 14 and 15 receive centrifugal force as the differential case 1 rotates and separate from each other, so that wear due to contact between both shafts hardly occurs. When it is necessary to prevent even a slight contact wear of the short pinion shafts 14 and 15, a protrusion indicated by the reference numeral 23 is provided in the center of the inside of the hollow sleeve 22 to maintain the distance between the shafts 14 and 15. May be. Further, the hollow sleeve 22 keeps the shaft centers of both the short pinion shafts 14 and 15 on the same line in this driving state, thereby preventing the misalignment of both shafts and ensuring smooth rotation. The hollow sleeve 22 can achieve substantially the same operation by the example shown in FIG.

In FIG. 3, a pair of pinion gears 12 and 13 in the case body 7 are a pair of short pinion shafts 1.
4,15, and both short pinion shafts 14,15
Hollow sleeves 22a and 22b having the same shape are rotatably fitted on the outer peripheral surfaces of the mutually opposing portions of the two. In this case, the hollow sleeves 22a and 22b have the same length B, and the length (2 × B) is equal to that of the pair of pinion gears 12 and 13.
The length is set to be close to the distance between them, and thereby the displacement of the hollow sleeves 22a and 22b in the pin center line L1 direction is restricted. Moreover, the pair of identically shaped hollow sleeves 22a, 22b have an outer diameter C of the side gear 16,
It is set to a value close to the interval of 17 and the hollow sleeve 22
The outer circumferences of a and b are slidably arranged between the facing surfaces of the side gears 16 and 17. Therefore, the opposing portions of the two short pinion shafts 14, 15 are regulated by the side gears 16, 17 via the hollow sleeves 22a, 22b from the pin center line L1.
The core misalignment of 5 is prevented.

In the differential device of FIG. 1, in order to prevent the pair of short pinion shafts 14 and 15 from protruding from the case body 7, the stopper lid 20 closes the opening of the through hole 19, and the bottomed concave hole 18 is formed. Was used. Instead of this, as a modification of the differential device of FIG.
Short pinion shaft 1 with stopper as shown in Fig. 4
4b and 15b may be used. In this case, the case body 7
The pair of pinion gears 12 and 13 therein is pivotally supported by the pair of short pinion shafts 14b and 15b.

Each short pinion shaft 14b, 1 here
5b is rotatably fitted into each of the pinion gears 12 and 13, and its tip end is rotatably fitted into the through hole 19 of the case body 7. Moreover, the short pinion shafts 14b and 15b are provided with protrusions 141 and 151, respectively, on the inner side surfaces of the case main body 7 which are mutually opposing portions. These protrusions 141 and 151 are provided for each pinion gear 12,
It is slidably locked to the inner side surface of 13 to prevent the short pinion shafts 14b and 15b from falling out of the differential case. The short pinion shaft 14b,
The movement of 15b in the direction of approaching each other can be realized by an appropriate means, for example, by interposing a spacer or a spring between both shafts, or the shaft 14
It can also be realized by providing unevenness for preventing relative movement in the axial direction between b and 15b and the pinion gear or the differential case.

In the above description, it was explained that each differential device transmits the rotational force from the input side to the left and right wheels, but instead of this, the present invention is applied to a center differential that branches the rotation to the front and rear wheels. Well, in this case, the same effect can be obtained.

[0026]

As described above, according to the first aspect of the invention, the pair of pinion gears are pivotally supported by the two short pinion shafts, respectively, and both short pinion shafts are relative to the differential case and the pinion gear. It is rotatable. Therefore, even if the left and right wheels of the vehicle have a large difference in rotation and each pinion gear rotates at high speed, each short pinion shaft rotates together, and the relative rotation between each pinion gear and each short pinion shaft is relatively large. It can be kept small, and the relative rotation between each short pinion shaft and the pinion gear can be reduced. Therefore, seizure can be reliably prevented during this period, and the durability of the device can be secured.

According to the invention of claim 2, in the differential device according to claim 1, a stopper is provided in the differential case. Therefore, in particular, the stopper can surely prevent the short pinion shaft from falling out of the differential case.

According to the invention of claim 3, in the differential device according to claim 1, the projection is formed on the side surface of the short pinion shaft. Therefore, in particular, the protruding portion can reliably prevent the short pinion shaft from falling out of the differential case.

According to the invention of claim 4, in the differential device according to claim 1, a common hollow sleeve is rotatably fitted on the outer circumferences of the opposing portions of both short pinion shafts. Therefore, it is possible to prevent the rotational axis misalignment of both the short pinion shafts and to ensure smooth rotation of the both shafts and the pinion gear.

According to a fifth aspect of the present invention, in the differential device according to the first to third aspects, the hollow sleeves are rotatably fitted to the outer circumferences of the opposing portions of the two short pinion shafts, respectively, and the both hollow sleeves. The outer periphery of the is arranged slidably between the facing surfaces of the side gears. For this reason,
The misalignment of the rotation axes of both short pinion shafts can be restricted by both side gears via the hollow sleeve, and smooth rotation of both shafts and pinion gears can be ensured.

[Brief description of drawings]

FIG. 1 is a cutaway sectional view of an essential part of a differential device to which the present invention is applied.

FIG. 2 is a vertical cross-sectional view of a differential case of the differential device shown in FIG.

3 is an enlarged cross-sectional view of a differential case used in a modification of the differential device of FIG.

FIG. 4 is an enlarged cross-sectional view of a differential case used in another modification of the differential device of FIG.

FIG. 5 is a cross-sectional view of a main part of a conventional device.

[Explanation of symbols]

 1 differential case 2,3 output shaft 4 housing 7 case body 9 input shaft 11 ring gear 12,13 pinion gear 14,15 short pinion shaft 14b, 15b short pinion shaft 141,151 protrusion 16,17 side gear 18 recessed hole 19 through hole 22 hollow sleeves 22a, 22b hollow sleeve L rotation center line L1 pin center line

Claims (5)

[Claims] 1. A differential case having an input ring gear,
A differential device comprising a pair of pinion gears pivotally supported in the differential case and a pair of side gears mounted on an output shaft and meshing with the pair of pinion gears, the pinion gear pivotally supporting the pair of pinion gears. A differential device characterized in that a shaft is divided into two short pinion shafts between both pinion gears, and the both short pinion shafts are rotatable relative to the differential case and the pinion gear. 2. The differential device according to claim 1, wherein the differential case is provided with a stopper for preventing the short pinion shaft from falling out of the differential case. 3. The differential device according to claim 1, wherein a projection is formed on a side surface of the short pinion shaft to prevent the short pinion shaft from falling out of the differential case. . 4. The differential device according to claim 1, wherein a common hollow sleeve is rotatably fitted on outer circumferences of the opposed portions of the two short pinion shafts. 5. The differential device according to any one of claims 1 to 3, wherein hollow sleeves are rotatably fitted to the outer circumferences of the facing portions of the both short pinion shafts, respectively, and the outer circumferences of both hollow sleeves of the side gears. A differential device characterized in that it is slidably disposed between opposed surfaces.