JP2561144Y2 - Power transmission mechanism seal structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for a power transmission mechanism.

[0002]

2. Description of the Related Art Conventionally, for example, a power transmission device provided in a forklift driven by the power of an engine is
A clutch for connecting and disconnecting engine power, a transmission for changing the driving torque and rotation speed of the drive wheels, a propeller shaft for transmitting engine power to the drive wheels via the clutch and the transmission, a differential gear, a driving axle, and the like. It is configured.

As shown in FIG. 4, power from the transmission is transmitted to a differential yoke joint 52 connected to a transmission yoke joint 53 and a universal joint 50. The differential-side yoke joint 52 is spline-coupled to a gear 55 disposed in a housing 54 of the differential 51. The housing 54
An oil seal 57 is provided between the housing 54 and the shaft portion 56 of the differential-side yoke joint 52 to prevent the leakage of the lubricating oil.
Is attached.

The oil seal 57 has dust lips 58a and 58b. This dust lip 5
8a comes into contact with a metal deflector 59 press-fitted into the shaft portion 56 of the differential-side yoke joint 52, and the dust lip 58b is
The contact with dust 6 prevents dust from entering the housing 54 from the outside.

[0005]

In the above-described sealing structure, the differential yoke joint 52 slides (about ± 3 mm) in the front-rear direction (the left-right direction in the figure) while the forklift is running. The length of the press-fit surface 60 of the deflector 59 that contacts the shaft portion 56 of the joint 52 is restricted.

That is, when the differential-side yoke joint 52 moves rightward in the drawing, the press-fitting surface 60 is prevented from contacting with the press-fitting surface 60 of the deflector 59 and the dust lip 58b of the oil seal 57. The distance from the strip 58b must be at least the sliding distance (3 mm or more) of the yoke 52 on the transmission side.

As a method for maintaining the distance between the press-fit surface 60 of the deflector 59 and the dust lip 58b,
There are cases where the dust lip 58b is formed short and the distance therebetween is maintained, and cases where the press-fit surface 60 of the deflector 59 is formed short and the distance therebetween is maintained.

However, when the former dust strip 58b is formed to be short, the adhesiveness between the housing 54 and the shaft portion 56 is reduced, and there is a possibility that dust may enter. Therefore, the dust strip 58b is formed to be short. It is not possible. Therefore, the length of the press-fitting surface 60 of the deflector 59 is made shorter, and the distance between the press-fitting surface 60 and the dust lip 58b is maintained.

However, when the length of the press-fitting surface 60 is short, there is a problem that the deflector 59 is easily deformed. That is, when pebbles, muddy water, and the like splashed during traveling of the forklift strike the outer peripheral surface 62 of the deflector 59, the impact may deform the deflector 59 in some cases.

As a result, water enters between the flange portion 64 of the differential side yoke joint 52 and the regulating surface 63 of the deflector 59, and rust is generated on the outer periphery of the shaft portion 56 of the differential side yoke joint 52, and the oil seal 57 is formed. However, there is a problem that the sealing performance is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its purpose is to reduce the deformation of the deflector due to an external impact and to prevent water from flowing between the deflector and the oil seal. It is an object of the present invention to provide a seal structure of a power transmission mechanism that can prevent intrusion of a power transmission mechanism.

[0012]

According to the present invention, a yoke joint spline-coupled to an output gear of a transmission and a yoke joint spline-coupled to a differential reduction gear are universally provided. While being connected by a joint, an oil seal is interposed between the transmission or the differential case and the yoke joint, and a flange is formed on the flange portion of the yoke joint,
An O-ring is attached to a base end of a shaft portion of the yoke joint, and an annular deflector having a substantially U-shaped cross section is press-fitted between the convex portion formed on the flange portion and the shaft portion to press the O-ring. The gist of the invention is that a dust lip formed on the oil seal is brought into contact with the deflector.

[0013]

According to the present invention, even if pebbles or muddy water splashed up during traveling of the vehicle collides with the vicinity of the flange portion of the yoke joint, the projection is formed on the flange portion. The rate at which pebbles and mud hit the deflector is reduced.

Further, since the outer peripheral surface of the deflector also becomes a press-fitting surface by forming a convex portion on the flange portion of the yoke joint, the entire press-fitting area is increased. As a result, the deflector is less likely to be deformed. Further, by disposing the O-ring at the base end of the shaft portion of the yoke joint, water does not enter between the oil seal and the deflector even when the deflector is deformed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG. As shown in FIG. 1, the differential 1 includes a housing 2, a reduction gear 3 rotatably housed in the housing 2, an output gear 4 meshing with the reduction gear 3, and the like.

The shaft portion 6 of the differential side yoke joint 5 is spline-connected to the reduction gear 3. A universal joint 8 is provided on the flange portion 7 of the differential-side yoke joint 5.
The yoke joint 9 on the transmission side is connected via the transmission. That is, the differential-side yoke joint 5 rotates with the rotation of the reduction gear 3 of the differential 1, and the transmission-side yoke joint 9 connected by the universal joint 8 also rotates with the rotation. Also,
The housing 2 of the differential 1 is filled with lubricating oil for lubricating the reduction gear 3, the output gear 4, and the like. In this embodiment, similarly to the conventional case, the differential-side yoke joint 5 is 3 mm back and forth.
It slides to the extent.

As shown in FIGS. 1 to 3, a projection 10 is integrally formed on the flange portion 7 of the differential side yoke joint 5 so as to protrude toward the housing 2 side. An O-ring 11 is attached to the base end of the shaft portion 6 on the flange portion 7 side. Between the convex part 10 and the shaft part 6, a deflector 12 formed in an annular shape with a substantially U-shaped cross section is press-fitted. Therefore, the O-ring 11 is connected to the shaft 6 and the deflector 1.
2 is held in a pressed state.

The two surfaces of the deflector 12, which are in contact with the shaft portion 6 and the surface in contact with the convex portion 10, are press-fit surfaces 13,
The movement of the deflector 12 toward the universal joint is restricted by the restriction surface 12a coming into contact with the flange portion 7.

An oil seal 15 is provided between the housing 2 and the shaft 6. The oil seal 15 is formed of a lip 16 made of soft rubber and a metal support member 17, which are integrally formed by injection molding. The lip 16 is formed by a seal portion 18 and dust lips 19 and 20. The seal portion 18 is in contact with the outer periphery of the shaft portion 6 of the differential side yoke joint 5 to prevent leakage of the differential oil filled in the housing 2. A spring ring 21 is provided on the outer periphery of the seal portion 18. The sealing force of the seal portion 18 is further improved by the tightening force of the spring ring 21.

Further, the one dust lip 19 contacts the outer periphery of the shaft portion 6 of the differential-side yoke joint 5, and the other dust lip 20 contacts the surface of the deflector 12 which faces the press-fitting surface 13. Dust is prevented from entering the housing 2.

As described above, in the present embodiment, the convex portion 10 is formed on the flange portion 7 of the differential-side yoke joint 5.
Is formed, and the deflector 12 is press-fitted between the convex portion 10 and the shaft portion 6, so that pebbles and mud splashed by the forklift during traveling run near the flange portion 7 of the differential side yoke joint 5. Even if a collision occurs, the projection 10 acts as a cover for the deflector 12, so that the rate at which pebbles and muddy water collide directly with the deflector 12 is reduced. In addition, unlike the related art, the press-fitting surface of the deflector 12 is not only the portion in contact with the shaft portion 6 but also the contact portion with the convex portion 10 is the press-fitting surface 14.
The overall press-fit area is increased. As a result, the deflector 12 is less likely to be deformed.

Further, the shaft portion 6 and the deflector 12
By mounting the O-ring 11 in between, the water can be reliably prevented from entering between the oil seal 15 and the deflector 12 even if the restricting surface 12a of the deflector 12 is separated from the flange portion 7.

As a result, it is possible to reliably prevent the outer peripheral surface of the shaft portion 6, that is, the seal surface, with which the dust lip 19 and the seal portion 18 of the oil seal 15 come into contact, from generating rust.

[0024]

[Effect of the Invention] As described in detail above, according to the present invention,
It is possible to reduce the deformation of the deflector due to the impact from the outside, and to prevent water from entering between the deflector and the oil seal, and to prevent rust from being generated on the shaft of the differential side yoke joint. It has an excellent effect that it can be done.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a differential seal structure according to an embodiment of the present invention;

FIG. 2 is a partial cross-sectional view of a differential-side yoke joint.

FIG. 3 is a sectional view of a differential-side yoke joint, a deflector, and an oil seal.

FIG. 4 is a partial cross-sectional view showing a conventional differential seal structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Differential, 2 ... Housing, 3 ... Reduction gear, 5 ... Differential side yoke joint, 6 ...
Shaft part, 7 ... Flange part, 8 ... Universal joint, 9 ... Transmission side yoke joint, 10 ... Protrusion, 1
DESCRIPTION OF SYMBOLS 1 ... O-ring, 13, 14 ... Press-fit surface, 15 ... Oil seal, 19, 20 ... Dustrip

Claims (1)

(57) [Scope of request for utility model registration] A yoke joint spline-coupled to an output gear of a transmission and a yoke joint spline-coupled to a reduction gear of a differential, connected by a universal joint, and a case of the transmission or the differential; An oil seal is interposed between the yoke joint and a convex portion is formed on the flange portion of the yoke joint, and an O-ring is attached to a base end of a shaft portion of the yoke joint to form a convex portion formed on the flange portion. A power transmission mechanism formed by press-fitting an annular deflector having a substantially U-shaped cross section between the portion and the shaft portion, pressing the O-ring, and bringing a dust lip formed on the oil seal into contact with the deflector.