JP2595256Y2 - Drive shaft - Google Patents

Description

[Detailed description of the invention]

[0001]

This invention relates to a drive shaft such as a propeller shaft of a vehicle, more specifically, a spline fitting between a drive side shaft and a driven side shaft, and a lubricant for lubricating the fitting portion. The present invention relates to a drive shaft capable of extending the life of a drive shaft.

[0002]

2. Description of the Related Art As shown in FIG. 4, a drive shaft of a vehicle has a spline 311 formed on an outer surface of an inner shaft 31 on a drive shaft side and an inner peripheral surface of a yoke-side outer shaft sleeve 32. The engraved spline 321 is spline-fitted, and is connected so as to be able to expand and contract to some extent in the axial direction so as to transmit rotational torque. These inner shaft 31 and outer shaft sleeve 32
The lubricant (grease) is hermetically sealed with a felt seal 33, a dust cap 34 which also serves as a sealant for the lubricant, and the like. Frequent refueling is required because the lubricant leaks easily and the sealing performance is not very high. For this reason, it has been proposed to circulate the lubricant in the spline fitting portion and to have a structure that does not require much lubrication. For example, as disclosed in Japanese Utility Model Laid-Open Publication No.
A spline shaft (inner shaft side), which is provided in the vicinity of the spline yoke (outer shaft side) and protrudes into a spline portion of the spline shaft (inner shaft side). 2. Description of the Related Art There is known a seal device for a sliding portion of a propeller shaft having a passage for returning a grease (lubricant) to a grease nipple. Alternatively, as disclosed in Japanese Utility Model Application Publication No. 60-79094, a closing member is provided so as to close a shaft hole in a sliding fitting portion between a spline fitted propulsion shaft and a yoke. , A bottomed hole is formed in the propulsion shaft, and a piston is inserted into this hole slidably in the axial direction to form an air chamber on the bottom side of this hole, and is formed between the closing member and the piston. There is known a seal structure in a sliding fitting portion between a propulsion shaft and a yoke, which is characterized in that grease is sealed in a space.

[0003]

It is preferable that a spline-fitted drive shaft be as easy as possible to be maintained with a reduced number of refueling operations. For that purpose, it is important to improve the sealing performance. Further, in order to extend the life of the lubricant, the structure must be such that the encapsulated lubricant is effectively used. The present invention has been made in view of the above-mentioned problems, and the lubricant sufficiently spreads to the spline fitting portion, so that the encapsulated lubricant can be effectively used, the life is extended, and the number of times of lubrication is reduced. The purpose is to provide a drive shaft that can do the same.

[0004]

That is, in order to solve the above-mentioned problems, the present invention has a structure in which the inner shaft (1) and the outer shaft sleeve (2) are spline-fitted, and the outer shaft sleeve is formed. (2)
A dust cap (6) having an air hole (6a) is fitted into one spline end, a sealing seal (3) is fitted into the other spline end, and the spline is slidable in a certain range in the axial direction. In the drive shaft, a concave portion (15) opening to the outside is formed in the inner shaft (1), and a small hole (16) is formed in the inner side of the concave portion so as to communicate with the external spline fitting portion. A seal (7) formed on the outer periphery with spline teeth having the same pitch as the outer spline shape of the inner shaft is attached to the outer periphery of the end. ) And a grease cap (8) having an air hole (82) extending from the outer peripheral groove (81) to the outside is attached. Further, the shim is formed in the radial direction of the concave portion (15) at the inner shaft end. -The space between the spline teeth of the Characterized in that bored a small hole (19) leading to 4).

[0005]

The operation when the drive shaft of the present invention is used as the above means will be described with reference to the accompanying drawings (FIGS. 1 to 3). First, the inner shaft 1 and the outer shaft sleeve 2 slide in the axial direction by a fixed distance, and the inner shaft 1 and the outer shaft sleeve 2 relatively shrink (that is, the inner shaft 1 moves in the white arrow direction). When sliding, the pressure in the space 10 is high and the pressure in the recess 15 and the space 4 is relatively low, but high-pressure air is provided in the air hole 6a and the grease cap 8. The pressure is adjusted by the air holes 82, the grooves 81 and the small holes 19. That is, the high-pressure air escapes to the outside through the air hole 6a, passes through the air hole 82, the groove 81, and the small hole 19, passes through the spline fitting space 4 and the small hole 16, and enters the concave portion 15, and the space 10 and the The pressure difference between the spline fitting space 4 and the recess 15 becomes small.

Next, when the inner shaft 1 and the outer shaft sleeve 2 slide in the direction in which the inner shaft 1 and the outer shaft sleeve 2 relatively extend (that is, the inner shaft 1 moves in the direction of the black arrow), the pressure in the space 10 decreases, The air pressure in the space inside the recess 15 becomes relatively high. In this case, air enters from outside through the air hole 6a, but the air in the concave portion 15 escapes from the small hole 16 to the space 10 through the spline fitting space 4, the small hole 19 and the air hole 82. In this case, since the inner shaft 1 and the outer shaft sleeve 2 are rotating together, a centrifugal force acts on the lubricant (grease G), and the lubricant (grease G) acts outside the shaft center (that is, from the position of the air hole 82). Is pushed out), so that only air flows out of the air holes 82. That is, the lubricant stays in the spline fitting space 4 due to the centrifugal force and does not flow out. Accordingly, the lubricant sufficiently spreads over the splines 11 and 21 of the inner shaft 1 and the outer shaft 2 and hardly flows out of the closed space 4 to the outside, so that the lubricant lasts longer.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the present invention will be described below with reference to the drawings. 1 is an axial sectional view of the drive shaft of the present invention, FIG. 2 is an enlarged view of a portion P in FIG. 1, and FIG.
FIG. 3 is a view taken in the direction of arrow Q in FIG. 2. In this drive shaft, a spline 11 is engraved on an outer surface of an inner shaft 1 on a driving side, and a spline 21 is engraved on an inner peripheral surface of an outer shaft sleeve 2 of a driven side yoke. The rotational torque is transmitted so as to be slidable within a certain range. At the end of the inner shaft 1, a step 12 is formed and a key groove 13 is provided.

Next, one of the spline fitting portion spaces 4 between the inner shaft 1 and the sleeve 2 is hermetically sealed with a felt seal (sealing seal) 3.

A hole 14 opening to the outside and a recess 15 having a diameter slightly smaller than the diameter of the hole 14 are formed in the center of the inner shaft 1 on the driving side. Are formed so as to communicate with the external spline fitting space 4. A lubricant (grease) G is provided in the recesses 15 and the small holes 16.
Is filled. A plug hole 22 is formed in the outer shaft sleeve 2 and a plug 5 is fitted therein. When filling the lubricant, the plug 5 is removed and filled. A dust cap 6 having an air hole 6a is fitted into the end of the outer shaft sleeve 2 so as to prevent foreign matter from entering, and to allow relative movement between the inner shaft 1 and the outer shaft sleeve 2. It functions to adjust the pressure of the internal space 10.

Reference numeral 7 denotes a seal attached to one end of the inner shaft 1 and made of, for example, an iron rubber.
As shown in the figure, spline teeth 71 having the same pitch as the shape of the outer spline 11 of the inner shaft 1 are formed on the outer periphery.
A convex portion 72 is formed on the inner peripheral side of the seal 7. The convex portion 72 is fitted to a key groove 13 provided in a step portion 12 formed at one end of the inner shaft 1, and is attached by a snap ring 17. is there. Thus, the seal 7
Is fixed immovably in both the circumferential direction and the axial direction.
The step 12 of the inner shaft 1 is provided with a screw to seal
May be "screwed", but in this case, the pitch of the splines must be adjusted and fixed.

Reference numeral 8 denotes a grease cap 8 made of, for example, an iron rubber, which is attached so as to close a recess 15 formed in the center of the inner shaft 1. A groove 81 is formed in the outer periphery of the grease cap 8, and a small air hole 82 communicating from the outer peripheral groove 81 to the outside is formed. The grease cap 8 is fixed by a holding ring 9. The holding ring 9 is fitted and fixed in an inner circumferential groove 18 formed near the end of the hole 14 provided at one end of the inner shaft 1. Further, in the vicinity of the end of the inner shaft 1, the outer circumferential groove 81 of the grease cap 8, the seal 7, and the spline 1 are provided.
A small hole 19 communicating with the space 4 between the fitting portions 1 and 21 is formed.

This drive shaft is constructed as described above. When the inner shaft 1 and the outer shaft sleeve 2 are spline-fitted, the dust cap 6, the inner shaft 1 and the outer shaft sleeve 2
The space between the inner shaft 1 and the outer shaft sleeve 2 is defined by a space 10 between the inner shaft 1 and the outer shaft sleeve 2 between the space 10 and the recess 15 for filling the lubricant of the inner shaft 1 communicating with the spline fitting space 4. The axial movement will result in a relative pressure difference. Thus, the inner shaft 1 and the outer shaft sleeve 2 slide in the axial direction by a certain distance, and the inner shaft 1 and the outer shaft sleeve 2 relatively contract (that is, the inner shaft 1 is a white arrow). (In the direction of movement), the pressure in the space 10 is high and the pressure in the recess 15 and the space 4 is relatively low.
The pressure is adjusted by the air holes 82, the grooves 81, and the small holes 19 formed in the scap 8. That is, the high-pressure air escapes to the outside through the air hole 6a, passes through the air hole 82, the groove 81, and the small hole 19, passes through the spline fitting space 4 and the small hole 16, and enters the concave portion 15, and the space 10 and the The pressure difference between the spline fitting space 4 and the recess 15 becomes small.

Next, when the inner shaft 1 and the outer shaft sleeve 2 slide in the direction in which the inner shaft 1 and the outer shaft sleeve 2 relatively extend (that is, the inner shaft 1 moves in the direction of the black arrow), the pressure in the space 10 decreases, The air pressure in the space inside the recess 15 becomes relatively high. In this case, air enters from outside through the air hole 6a, but the air in the concave portion 15 escapes from the small hole 16 to the space 10 through the spline fitting space 4, the small hole 19 and the air hole 82. In this case, since the inner shaft 1 and the outer shaft sleeve 2 are both rotating, a centrifugal force acts on the lubricant (grease G), and the lubricant (grease G) is applied outside the shaft center (that is, from the position of the air hole 82). Is pushed out), so that only air flows out of the air holes 82. That is, the lubricant stays in the spline fitting space 4 due to the centrifugal force and does not flow out. Accordingly, the lubricant sufficiently spreads over the splines 11 and 21 of the inner shaft 1 and the outer shaft 2 and hardly flows out of the closed space 4 to the outside, so that the lubricant lasts longer.

[0014]

As described in detail above, according to the drive shaft of the present invention, not only can the splice fitting portion and the sealability of the lubricant holding space be improved, but also the spline fitting portion can be sufficiently lubricated. The medicine can be distributed. Further, it is possible to extend the life of the lubricant while constantly lubricating the spline connection portion of the drive shaft. Further, the amount of the lubricant used can be reduced, and the maintenance interval can be made longer and easier.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a drive shaft according to the present invention.

FIG. 2 is an enlarged view of a part P in FIG.

FIG. 3 is a view taken in the direction of arrow Q in FIG. 2;

FIG. 4 is an axial sectional view of a conventional drive shaft.

[Explanation of symbols]

Reference Signs List 1 inner shaft 11 spline 12 step 13 key groove 15 recess 16 small hole 2 outer shaft sleeve 21 spline 3 sealing seal 4 spline fitting space 6 dust cap 6a air hole 7 seal 71 spline tooth 8 −Scap 81 Outer peripheral groove 82 Air hole 10 Dust cap inner space 9 Press ring 19 Small hole

Claims (1)

(57) [Scope of request for utility model registration] An inner shaft and an outer shaft sleeve are spline-fitted. A dust cap having an air hole is fitted into one spline end of the outer shaft sleeve, and the other spline end is fitted into the other spline end. In a drive shaft in which a sealing seal is fitted and slidable in a predetermined range in the axial direction, a concave portion which opens to the outside is formed in the inner shaft, and a small hole is provided in the concave portion so as to communicate with the external spline fitting portion. A seal is formed on the outer periphery of the inner shaft end at the outer periphery with spline teeth having the same pitch as the outer spline shape of the inner shaft, and an outer peripheral groove is formed at the concave end of the inner shaft. At the same time, a grease cap provided with an air hole extending from the outer peripheral groove to the outside is attached, and further, a space is formed between the spline teeth of the seal and the spline fitting in the radial direction of the recess at the inner shaft end. Characterized by drilling small holes Drive shaft.