JPH11201178A - Drive shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate periodic oiling, facilitate maintenance, and easily slide a spline part. SOLUTION: A drive shaft formed in such a constitution that an inner shaft and a cylindrical sleeve are spline-fitted to each other, a tightly sealing seal which is brought into sliding contact with an inner shaft circumferential surface is fitted and fixed to a tip end part of the cylindrical sleeve, and the inner shaft and the cylindrical sleeve are freely slid in an axial direction within a constant range; an axial direction penetrating hole 12 is formed on an axial part of the inner shaft 1, a tightly sealing member 8 for tightly sealing the axial direction penetrating hole 12 at an inner shaft tip end surface side is fixed to the cylindrical sleeve 2 or the inner shaft 1, and a penetrating hole inner surface formed between a way of the axial direction penetrating hole 12 and the inner shaft tip end surface is formed on a surface 14a whose diameter is enlarged toward the inner shaft 1 end surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive shaft such as a propeller shaft of a vehicle.

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventional drive shaft includes a spline 21 formed on a peripheral surface of an inner shaft 20;
Spline 23 formed on the inner peripheral surface of cylindrical sleeve 22
Are spline-fitted, and are connected so as to be able to expand and contract to some extent in the axial direction to transmit the rotational torque. The spline fitting portion between the inner shaft 20 and the cylindrical sleeve 22 fits and fixes a dust cap 27 that covers the inner shaft 20 end surface 26 and also serves as a grease encapsulation at one spline end 24 of the cylindrical sleeve 22. A sealing seal 28 slidingly contacting the peripheral surface of the inner shaft 20 is fitted and fixed to the other spline end 25. The grease is regularly replenished to prevent wear and galling of the spline portion.

[0003]

The above drive shaft needs to be refueled periodically, but the operation is troublesome. Further, when used without lubrication for a long period of time, abnormal wear may occur in the spline portion due to insufficient grease due to grease leakage, and axial sliding resistance may increase. Furthermore, if the seal is completely sealed to prevent grease leakage, the internal pressure changes due to the axial sliding of the spline section,
It may be difficult to expand and contract.

It is an object of the present invention to provide a drive shaft that does not require periodic lubrication, facilitates maintenance, and facilitates sliding of a spline portion.

[0005]

As a means for solving the above-mentioned problems, a sealing seal which is spline-fitted between an inner shaft and a cylindrical sleeve and which comes into sliding contact with the peripheral surface of the inner shaft at the end of the cylindrical sleeve. In the drive shaft, which is fitted and fixed and the inner shaft and the cylindrical sleeve are slidable in the axial direction within a certain range, an axial through hole is formed in the axial center portion of the inner shaft. Is fixed to the cylindrical sleeve or the inner shaft, and the inner surface of the through hole extending from the middle of the axial through hole to the inner shaft front surface is expanded toward the inner shaft end surface. It is characterized in that it is formed on a surface having a diameter.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. An inner shaft 1 having a flange yoke 5 joined to one end by welding and having a spline 3 formed on the outer peripheral surface, and a cylinder having a flange yoke 6 integrally formed on one end and a spline 4 formed on the inner peripheral surface. The sleeve 2 is spline-fitted, and the inner shaft 1 and the tubular sleeve 2 expand and contract by a certain distance and transmit rotational torque.
A dust cap 8 having a U-shaped cross section that covers the front end face 7 of the inner shaft 1 is fitted and fixed to the inner surface of the flange yoke 6 at one spline end 2a of the cylindrical sleeve 2, and the cylinder at the other spline end 2b. A seal 9 slidingly contacting the outer peripheral surface of the inner shaft 1 is fitted and fixed to the outer peripheral surface of the inner sleeve 1.
And the cylindrical sleeve 2 are slidable in the axial direction within a certain range. A space 10 is formed inside the flange yoke 5 connected to the inner shaft 1.

The axial center of the inner shaft 1 has an axial through hole 12 communicating with a space 11 in the dust cap 8 and an inner space 10 of the flange yoke 5 connected to the inner shaft 1. Are formed. The axial through-hole 12 is formed on the space portion 10 side of the flange yoke 5 connected to the inner shaft 1 with a first hole portion 13 parallel to the axis line, and connected to the first hole portion 13 and on the dust cap 8 side. Is formed from the second hole portion 14 of the conical surface 14a whose diameter increases toward the end surface 7 of the inner shaft 1. Space 1 between the dust cap 8 and the end of the inner shaft 1
1 is filled with grease. The volume of the second hole portion 14 of the conical surface 14a does not leak from the first hole portion 13 to the space portion 10 when the inner shaft 1 and the cylindrical sleeve 2 are reduced to the maximum, and the sealed grease overflows. It is large enough. Instead of the dust cap 8, a sealing member such as a cap for covering the through hole 12 may be attached to the tip end surface 7 of the inner shaft 1, and the through hole 12 is not limited to a conical surface as long as the diameter of the through hole 12 is increased. .

Next, the operation will be described. When the drive shaft is used and the spline portion is reduced, the grease moves inside the second hole 14 on the conical surface,
At this time, since the air in the through hole 12 escapes through the first hole portion 13, a large force is not required to reduce the spline portion.

On the contrary, when the spline portion is extended, a part of the grease is removed from the space 1 inside the dust cap 8.
In addition to returning to 1, the air is sucked through the first hole portion 13, so that an unnecessarily large force is not required for the extension of the spline portion. At this time, some grease remains inside the second hole portion 14 having the conical surface 14a, but the grease moves along the conical surface 14a due to the centrifugal force due to the rotation of the drive shaft, and the original dust cap 8 The process returns to the internal space 11. As a result, the grease is in the first hole 1
The grease moves in a direction away from 3 and there is no fear that the grease moves to the space 10.

[0010]

According to the present invention, periodic lubrication is not required, maintenance is facilitated, and lubrication of the spline portion by grease can be sufficiently performed to prevent abrasion of the spline portion and facilitate sliding of the spline portion. Can be done.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of an embodiment of the present invention.

FIG. 2 is an axial sectional view of a conventional drive shaft.

[Explanation of symbols]

 Reference Signs List 1 inner shaft 2 cylindrical sleeve 3, 4 spline 8 dust cap 12 through hole 14a conical surface

Claims (1)

[Claims] An inner shaft and a cylindrical sleeve are spline-fitted, and a sealing seal slidingly contacting the inner shaft peripheral surface is fitted and fixed to a distal end portion of the cylindrical sleeve. In a drive shaft which is slidable in the axial direction within a certain range, a sealing member which forms an axial through hole in the axial center portion of the inner shaft and seals the axial through hole on the inner shaft tip surface side is a cylinder. A drive shaft fixed to a sleeve or an inner shaft, wherein an inner surface of a through hole extending from a middle portion of the axial through hole to a tip surface of the inner shaft is formed to have a diameter increasing surface toward an inner shaft end surface.