JP3196997B2 - Parallel shaft differential gearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel shaft differential gear in which a thrust washer is interposed between end faces of a pair of sun gears.

[0002]

2. Description of the Related Art Generally, a parallel shaft differential gear device includes a housing, a pair of sun gears, and at least a pair of planetary gears. When the housing is driven to rotate, the rotation is performed via the planetary gears. And transmitted to each sun gear. Then, an output shaft such as an axle connected to each sun gear rotates. In this case, when the magnitude of the load acting on the output shaft is the same, the housing, the sun gear and the planetary gear rotate integrally, and when the magnitude of the load is different, one of the sun gears moves relative to the housing. The sun gear rotates at a low speed, and the other sun gear rotates at a high speed. That is, they rotate differentially.

[0003] In the parallel shaft differential gear device having the above-described structure, thrust washers are disposed between the end faces of the sun gears and the housing and between the end faces of the sun gears. It is designed to rotate together. Therefore, at the time of the differential rotation, the thrust washer comes into sliding contact with the end face of the sun gear. Then, due to the frictional resistance generated at this time, a larger torque is transmitted to the output shaft rotating at a low speed than the output shaft rotating at a high speed. The ratio of the magnitude of the torque transmitted to each output shaft (torque bias ratio) is determined based on the magnitude of the frictional resistance.

[0004] Each thrust washer is gradually worn due to sliding contact with the end face of the sun gear. In this case, the thrust washer (end washer) disposed between the sun gear and the housing has one end face only in sliding contact with the sun gear, whereas the thrust washer disposed between the pair of sun gears. Both ends of the (center washer) are in sliding contact with each sun gear. For this reason, there was a problem that the center washer was easily worn out early.

Therefore, in a parallel shaft differential gear device described in Japanese Patent Application Laid-Open No. 5-272600, a through hole is formed in a center washer from one end surface to the other end surface. The through-hole is arranged so as to face the gear portion of the sun gear, and holds the lubricating oil fed by the feeding action of the torsion teeth of the sun gear. By allowing the lubricating oil held in the through-hole to enter between the center washer and the end face of the sun gear, early wear of the center washer is prevented.

[0006]

When the through hole is formed in the center washer as in the parallel shaft differential gear device described in the above-mentioned publication, the contact area between the center washer and the sun gear is reduced accordingly. As a result, there has been a problem that the contact pressure increases and seizure occurs.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an invention according to claim 1 is a housing which is driven to rotate, and an axis in the housing is defined by an axis of the housing. A pair of sun gears rotatably supported in a matched state, at least a pair of planetary gears rotatably arranged in the housing, meshing with the pair of sun gears, respectively, and meshing with each other, and the pair of suns; In a parallel shaft differential gear device including a ring-shaped thrust washer disposed between end faces of gears, a holding member is provided inside the thrust washer, and the holding member holds lubricating oil therein, It is characterized in that an oil holding space which is partially open is formed on the outer surface of the holding member. In this case, it is desirable to arrange an axle spacer straddling the adjacent ends of the pair of sun gears and to use the axle spacer as the holding member for the reason described later. . It is preferable that the holding member is formed of a porous material having a large number of fine holes, and the oil holding space is formed by the large number of holes. Further, in the oil holding space,
It is desirable to fill an oil holder that holds the lubricating oil.

[0008]

According to the first aspect of the invention, the lubricating oil held in the oil holding space of the holding member flows out of the holding member by the rotation of the holding member. The lubricating oil that has come out on the outer surface enters between the thrust washer and the sun gear because the holding member is disposed inside the thrust washer. This effect is the same in the inventions described in claims 2 to 4.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG. 1 and 2 show a parallel shaft differential gear device A according to an embodiment of the present invention. FIG. 1 is a sectional view taken along line XX of FIG. 2, and FIG. 2 is a sectional view taken along line YY of FIG. It is. As shown in these figures, the parallel shaft differential gear device A
Has a housing 1, a pair of sun gears 2 and at least one pair (three pairs in this embodiment) of planetary gears 3.

The housing 1 is rotatably driven by an engine via a ring gear (not shown), rotates about its axis L, and includes a main body 11 and a lid 12. The main body 11 has a bottom 11a at one end,
The other end is formed in an open cylindrical shape. Lid 12
Has a disk shape, is fixed to the other end of the main body 11, and closes its opening.

On the bottom 11a of the main body 11, three oil introduction holes 11b penetrating therethrough are arranged at equal intervals in the circumferential direction. On the peripheral wall of the main body 11, oil introduction holes 11c penetrating therethrough are formed. Are formed at equal intervals in the circumferential direction. On the other hand, in the lid 12, an oil introduction oil 12a penetrating therethrough is formed so as to face the oil introduction hole 11b. The lubricating oil stored in the differential case is introduced into the housing 1 through these oil introduction holes 11b, 11c, 12a.

Further, support holes 11d and 12b penetrating on the axis L are formed in the bottom 11a and the lid 12, respectively. A pair of output shafts 4 and 4 such as axles are rotatably inserted into and supported by the support holes 11d and 12b. The pair of sun gears 2 and 2 are connected to ends of the output shafts 4 and 4 inside the housing 1, respectively. That is, the sun gear 2 has a through hole 21 at the center thereof, and a spline hole 22 is formed in the through hole 21. The sun gear 2 is connected to the output shaft 4 movably in the direction of the axis L and non-rotatably by fitting the spline shaft 41 formed on the outer periphery of the output shaft 4 into the spline hole 22. ing.

In the housing 1, three pairs of planetary gears 3, 3 are rotatably provided. The three pairs of planetary gears 3, 3 are arranged parallel to the axis L and at equal intervals in the circumferential direction. The paired planetary gears 3, 3 mesh with the sun gears 2, 2, respectively, and also mesh with each other. As a result, the driving torque input to the housing 1 is transmitted to the output shafts 4 and 4 via the planetary gears 3 and 3 and the sun gears 2 and 2, respectively, and the magnitude of the load acting on the output shafts 4 and 4 is reduced. If they are different, they rotate differentially.

An end washer 5 is disposed between the end face of each sun gear 2 and the housing 1. The end washer 5 is made of a thin metal disk, and has a ring shape by forming a through hole 51 at the center thereof. The frictional resistance between the end washer 5 and the housing 1 is greater than the frictional resistance between the end washer 5 and the sun gear 2, whereby the end washer 5 rotates integrally with the housing 1. The inner diameter of the through hole 51 is slightly larger than the outer diameter of the output shaft 4.

A center washer (thrust washer) 6 is arranged between the end faces of the sun gears 2 and 2.
The center washer 6 is made of a thin disk made of metal, and has a ring shape by forming a through hole 61 at the center thereof. The inside diameter of the through hole 61 is equal to or slightly larger than the outside diameter of the axle spacer 7 described later. On the outer peripheral surface of the center washer 6, three engaging projections 62 are arranged and formed at equal intervals in the circumferential direction. Each engagement projection 62 is fitted between the pair of planetary gears 3, 3, whereby the center washer 6 rotates integrally with the housing 1.

Axle spacers 7 are arranged in the through holes 21 and 21 of the sun gears 2 and 2 so as to straddle them. That is, at the adjacent ends of the through holes 21 and 21, the annular concave portions 23 and 23 are formed, respectively. On the other hand, the axle spacer 7 is a ring-shaped member having a circular cross section having a through hole 71 at the center, and both ends of the axle spacer 7 are rotatably fitted into the recesses 23, 23.

As is well known, the axle spacer 7 regulates the position of the output shafts 4 and 4 in the direction of the axis L, and abuts against the bottom surfaces of the recesses 23 and 23 (the surfaces facing the direction of the axis L). Cannot move further in the direction of the axis L. For example, when the axle spacer 7 abuts against the bottom surface of the concave portion 23 of one sun gear 2, when the output shaft 4 coupled to the other sun gear 2 abuts the axle spacer 7, one more sun gear 2
Cannot be moved to the side, thereby restricting the position of the output shaft 4. The other output shaft 4
The same applies to.

Incidentally, the length of the axle spacer 7 in the direction of the axis L is slightly shorter than the total length of the depths of the recesses 23 and 23 and the thickness of the center washer 6 in the same direction. 6 can come into contact with both sun gears 2 at the same time.

The axle spacer 7 is also used as a holding member for supplying lubricating oil between the center washer 6 and the sun gear 2. That is, the axle spacer 7 is made of a porous material such as sintered metal or ceramics, and has a large number of holes (not shown) formed therein. Many holes are filled with lubricating oil. Moreover, many holes are continuous with each other, and some of them are open to the outer surface of the axle spacer 7. Therefore, the lubricating oil held in the large number of holes gradually comes out of the outer surface of the axle spacer 7 and enters between the center washer 6 and the sun gears 2.

In the parallel shaft differential gear device having the above structure, the lubricating oil held by the axle spacer 7 gradually comes out on the outer surface and enters between the center washer 6 and the end faces of the sun gears 2. In particular, when the housing 1 rotates, the axle spacer (holding member) 7 rotates due to friction between the sun gears 2 and 2. Then, the lubricating oil filled in the holes comes out on the outer peripheral surface of the axle spacer 7 by centrifugal force. Then, the lubricating oil enters between the center washer 6 and each end face of the sun gears 2. Therefore, it is possible to prevent the center washer 6 from being worn early due to the sliding contact between the sun gears 2 and 2. Moreover, since the lubricating oil held by the axle spacer 7 is supplied, it is not necessary to form a hole for holding the lubricating oil in the center washer 6. Therefore, the contact area between the center washer 6 and the sun gears 2, 2 does not decrease.

Incidentally, the lubricating oil enters into the holes from the side surfaces and the inner peripheral surface of the axle spacer 7. In particular, when the housing 1 is stopped, the lubricating oil enters not only from the side surface and the inner peripheral surface but also from the outer peripheral surface. Thus, the holes are always filled with the lubricating oil. Therefore, the lubricating oil can be reliably supplied between the center washer 6 and the sun gears 2 and 2 without interruption.

In this embodiment, the axle spacer 7 for regulating the positions of the output shafts 4 and 4 is provided with a center washer 6.
Since it is also used as a holding member for holding the lubricating oil supplied between the sun gears and the sun gears 2, 2, there is no need to separately provide a new member as the holding member. Therefore, it is possible to prevent the manufacturing cost from increasing.

In the above embodiment, a large number of holes formed inside the axle spacer 7 are used as the holding space for holding the lubricating oil, but other holes can be used as the holding space. . Hereinafter, this point will be described.

The axle spacer 7A shown in FIG. 3 is made of metal such as steel, and has the same external shape as the axle spacer 7. However, in the axle spacer 7A, a number of vertical holes (holding spaces) 72 penetrating from the inner peripheral surface to the outer peripheral surface are formed therein, and the vertical holes 72 hold lubricating oil. .

The axle spacer 7B shown in FIG. 4 has a large number of lateral holes (holding spaces) penetrating from one end surface to the other end surface.
73, and the other configuration is the same as that of the axle spacer 7A. When the axle spacer 7B is used, the lubricating oil held in the lateral hole 73 once comes out on both end surfaces of the axle spacer 7B, and then moves to the outer peripheral surface due to centrifugal force caused by the rotation of the axle spacer 7B. Then, it enters between the center washer 6 and the sun gears 2.

The axle spacer 7C shown in FIG. 5 has annular grooves (holding spaces) 74 on its outer peripheral surface and both end surfaces, respectively.
Is formed. In this case, one annular groove 74 is formed on each of the outer peripheral surface and both end surfaces, but a plurality of annular grooves may be formed.

The axle spacer 7D shown in FIG. 6 has a large number of vertical grooves (holding spaces) 75 extending from the inner peripheral surface to the outer peripheral surface on both end surfaces, and a large number of longitudinal grooves extending from one end surface to the other end surface on the outer peripheral surface. A lateral groove (holding space) 76 is formed. In this case, the vertical groove 75 and the horizontal groove 76 communicate with each other, but they may be formed independently without communicating with each other.

The axle spacer 7E shown in FIG. 7 has a holding space 78 filled with an oil holding body 80 for holding lubricating oil. That is, the axle spacer 7E
Are composed of a metal main body 7a and a lid 7b, respectively, and an annular concave portion 77 is formed on one end surface of the main body 7a. By closing the annular concave portion 77 with the lid 7b, an annular holding space 78 is formed. The annular space 78 is filled with an oil holder 80 for holding lubricating oil. In this embodiment, a resin fiber, a metal fiber, a resin wire or a metal wire made of cotton is used as the oil holder 80. Such an oil retainer 80 can retain lubricating oil between fibers or between wires. As the other holding member, for example, a holding member made of a porous material constituting the axle spacer 7 can be used.

The lubricating oil held by the oil holding member 80 is allowed to come out of the outer surface of the axle spacer 7E, and the outer peripheral portion of the main body 7a is supplied to supply the lubricating oil. A large number of holes 79 reaching the holding space 78 are formed in the surface, the other end surface, the inner peripheral surface, and the lid 7b. These holes 79 also function as holding spaces.

The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, the holding spaces for the axle spacers 7 to 7E may be appropriately combined. For example, the vertical hole 72 of the axle spacer 7A and the axle spacer 7B
May be simultaneously formed in one axle spacer. In addition, instead of the main body 7a and the lid 7b of the axle spacer 7E, an external shape is created by a metal net,
The oil holding body 80 may be put in the inside.

[0031]

As described above, according to the first aspect of the present invention, early wear of the thrust washer can be prevented without reducing the contact area between the thrust washer and the pair of sun gears. The effect that it can be obtained is obtained. According to the invention of claim 2, since the axle spacer is also used as a holding member, it is not necessary to newly provide a holding member, and the manufacturing cost can be reduced correspondingly. According to the third aspect of the present invention, since the lubricating oil held in the large number of holes gradually comes out, lubricating oil is supplied between the axle spacer and the sun gear without excess or shortage and without running out of oil. be able to. This is the same in the invention according to claim 4.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the present invention, and is a sectional view taken along line XX of FIG. 2;

FIG. 2 is a sectional view taken along the line YY of FIG. 1 showing the same embodiment.

FIG. 3 is a view showing a second embodiment of the thrust washer according to the present invention, and FIG. 3 (A) is a plan sectional view thereof, and FIG.
(B) is a side view thereof.

FIG. 4 is a view showing a third embodiment of the thrust washer according to the present invention, wherein FIG. 4 (A) is a plan view thereof, and FIG.
(B) is a side sectional view thereof.

FIG. 5 is a view showing a fourth embodiment of the thrust washer according to the present invention, wherein FIG. 5 (A) is a plan view thereof and FIG.
(B) is a side sectional view thereof.

FIG. 6 is a view showing a thrust washer according to a fifth embodiment of the present invention, wherein FIG. 6 (A) is a plan view thereof and FIG.
(B) is a side sectional view thereof.

FIG. 7 is a view showing a sixth embodiment of the thrust washer according to the present invention, wherein FIG. 7 (A) is an AA of FIG. 7 (B).
7B is a cross-sectional view of FIG. 7A.

[Explanation of symbols]

 Reference Signs List A Differential gear device 1 Housing 2 Sun gear 3 Planetary gear 6 Center washer (thrust washer) 7 Axle spacer (holding member) 7A Axle spacer (holding member) 7B Axle spacer (holding member) 7C Axle spacer (holding member) 7D Axle Spacer (holding member) 7E Axle spacer (holding member) 72 Vertical hole (oil holding space) 73 Horizontal oil (oil holding space) 74 Annular groove (oil holding space) 75 Vertical groove (oil holding space) 76 Horizontal groove (oil holding space) ) 78 Oil holding space 79 holes 80 Oil holding body

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akinori Homan 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Kiyonari Ishikawa 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (56) References JP-A-47-19262 (JP, A) JP-A-6-323373 (JP, A) JP-A-6-42595 (JP, A) JP-A-5-272600 (JP, A) U.S.A. 60-127160 (JP, U) U.S.A. 6-16750 (JP, U) U.S. Pat. No. 5,342,256 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 57/00 -57/04 F16H 48/20

Claims (4)

(57) [Claims] A housing rotatably driven; a pair of sun gears rotatably supported in the housing so that an axis thereof is aligned with an axis of the housing; and a sun gear rotatably disposed in the housing. A parallel-shaft differential gear device comprising at least one pair of planetary gears meshing with a pair of sun gears and meshing with each other, and a ring-shaped thrust washer disposed between end faces of the pair of sun gears. A parallel shaft differential gear device comprising: a holding member provided inside a washer; a lubricating oil held inside the holding member; and an oil holding space partially open to an outer surface of the holding member. . 2. An axle spacer straddling the adjacent ends of the pair of sun gears, and the axle spacer also serves as the holding member. Item 2. The parallel shaft differential gear device according to Item 1. 3. The oil retaining space according to claim 1, wherein the holding member is formed of a porous material having a large number of fine holes, and the oil holding space is formed by the large number of holes. A parallel shaft differential gearing as described. 4. The parallel shaft differential gear device according to claim 1, wherein the oil holding space is filled with an oil holding body that holds lubricating oil.