WO2019009375A1

WO2019009375A1 - Sliding constant-velocity universal joint

Info

Publication number: WO2019009375A1
Application number: PCT/JP2018/025590
Authority: WO
Inventors: 健太伊藤; 圭介西尾
Original assignee: Ntn株式会社
Priority date: 2017-07-07
Filing date: 2018-07-05
Publication date: 2019-01-10
Also published as: JP2019015346A

Abstract

A sliding constant-velocity universal joint comprising an outside joint member 11 and an inside joint member 12 that transmits rotational torque between the inside joint member and the outside joint member 11 by means of balls 13 while allowing axial displacement and angular displacement, wherein a smaller-diameter part 34 of a boot 28, which seals a lubricant 27 inside the outside joint member 11 and closes off an opening in the outside joint member 11, is mounted on a shaft 21 extending from the inside joint part 12. A lip portion 41, which is not in contact with the outer circumferential surface of the shaft 21 when the inside joint member 12 is positioned in the center of the joint and which makes contact with the outer circumferential surface of the shaft 21 when the inside joint member 12 is axially displaced toward the interior of the joint, is provided on the inner circumferential surface of an intermediate portion 35 of the boot 28.

Description

Sliding type constant velocity universal joint

The present invention is used in power transmission systems of automobiles and various industrial machines, and is incorporated in, for example, a propeller shaft or a drive shaft of an automobile, and has a sliding constant velocity universal joint including a boot for preventing lubricant leakage from the inside of the joint. About.

For example, there are two types of constant velocity universal joints used as means for transmitting rotational force from an engine of an automobile to wheels at constant speed, a fixed constant velocity universal joint and a sliding constant velocity universal joint. These two constant velocity universal joints have a structure capable of connecting two shafts on the drive side and the driven side so that the two shafts can transmit rotational torque at a constant speed even at an operating angle.

For example, as a constant velocity universal joint assembled to a propeller shaft used in an automobile such as a 4WD vehicle or an FR vehicle, for example, there is a sliding constant velocity universal joint disclosed in Patent Document 1.

In this type of constant velocity universal joint, a lubricant such as grease is enclosed inside to ensure the lubricity at the sliding portion inside the joint during the operation of rotating while taking the operating angle. .

Therefore, in the constant velocity universal joint, the large diameter end of the boot is attached to the open end of the outer joint member and the shaft extending from the inner joint member is attached to the open end of the outer joint member in order to prevent the lubricant sealed inside the joint. The small diameter end portion is fixed by a boot band.

The boot mounted on the constant velocity universal joint disclosed in this patent document 1 has a structure in which a lip portion in contact with the outer peripheral surface of the shaft is provided on the inner peripheral surface of the small diameter end apart from the tightening and fixing portion by the boot band. Equipped with

As described above, by providing the lip portion that exhibits the sealing function, the sealing performance of the boot is improved, so that the leakage of the lubricant sealed in the inside of the joint is reliably prevented.

JP, 2006-308075, A JP, 2011-153662, A

By the way, in the constant velocity universal joint disclosed in Patent Document 1, the lip portion provided at the small diameter end portion of the boot prevents the lubricant filled inside the outer joint member from leaking to the outside, and the sealability is provided. Improve.

However, since the propeller shaft on which the constant velocity universal joint is assembled rotates at high speed, the internal pressure of the joint may increase due to heat generation during high speed rotation, or the boot life may be reduced due to deterioration due to heat generation.

In order to solve this problem, the present applicant has, for example, a slide disclosed in Patent Document 2 for the purpose of preventing the external leakage of the lubricant and preventing the rise of the joint internal pressure and the reduction of the boot life in advance. A dynamic constant velocity universal joint is proposed earlier.

In the sliding type constant velocity universal joint disclosed in Patent Document 2, the lip portion in contact with the outer peripheral surface of the shaft is formed on the outer joint member side portion of the inner peripheral surface of the end portion of the boot and the inside and outside of the boot are communicated. The ventilation groove is formed on the end side inner circumferential surface of the boot on the side opposite to the outer joint member.

In this sliding type constant velocity universal joint, the lip portion comes into contact with the outer peripheral surface of the shaft, so that the lubricant filled inside the outer joint member can be prevented from leaking to the outside, and a sufficient sealing property is secured. can do.

Further, by communicating the inside and the outside of the boot through the ventilation groove formed on the inner peripheral surface of the end portion of the boot, it is possible to suppress the rise in internal pressure of the joint due to heat generation at high speed rotation of the joint and to reduce the life of the boot beforehand. It can be prevented.

However, in the sliding type constant velocity universal joint disclosed in Patent Document 2, since the lip portion is always in contact with the outer peripheral surface of the shaft, the adjustment of the internal pressure of the joint can not be performed sufficiently, and deformation and wear of the boot There is a risk of damage or the like.

Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to prevent the external leakage of the lubricant and to suppress the rise in the internal pressure of the joint, and to prevent the deformation and wear and tear of the boot. An object of the present invention is to provide a sliding type constant velocity universal joint which can be prevented.

The sliding constant velocity universal joint according to the present invention is an inner joint member that transmits rotational torque while allowing axial displacement and angular displacement between an outer joint member and the outer joint member via a torque transmission member. And an end of the boot enclosing the lubricant in the outer joint member and closing the opening of the outer joint member is mounted on a shaft extending from the inner joint member.

As a technical means for achieving the above-mentioned purpose, when the inner joint member is located at the center of the joint, it is in a non-contact state with the outer peripheral surface of the shaft, and when the inner joint member is axially displaced inward of the joint The present invention is characterized in that a lip portion in contact with the outer peripheral surface of the boot is provided on the inner peripheral surface of the boot.

In the present invention, when the inner joint member is axially displaced to the rear side of the joint, the lip portion contacts the outer peripheral surface of the shaft, so that the lubricant filled inside the outer joint member can be prevented from leaking to the outside. And sufficient sealing performance can be secured.

On the other hand, when the inner joint member is located at the center of the joint, the lip is not in contact with the outer peripheral surface of the shaft, so that the inside and outside of the boot communicate with each other through the gap between the lip and the outer peripheral surface of the shaft The rise in internal pressure of the joint due to heat generation can be suppressed when the joint is rotating at high speed, and deformation and wear and breakage of the boot can be prevented in advance.

It is desirable that the lip portion in the present invention be in contact with the outer peripheral surface of the shaft by being deformed so that the bent portion of the boot approaches the outer peripheral surface of the shaft when the inner joint member is axially displaced to the joint back side. .

If such a structure is adopted, the lip portion contacts the outer peripheral surface of the shaft when the inner joint member is axially displaced from the center of the joint to the back side of the joint. Leakage can be effectively prevented.

In the present invention, it is desirable that the ventilation groove communicating the inside and the outside of the boot be provided on the inner peripheral surface of the end of the boot.

By adopting such a structure, the inside and the outside of the boot are communicated via the ventilation groove provided on the inner peripheral surface of the end portion of the boot, so that the joint internal pressure is further suppressed from rising due to heat generation at high speed rotation of the joint. be able to.

In the present invention, a structure in which at least one or more vent holes are provided at the shaft contact portion of the lip portion is desirable.

By adopting such a structure, when the inner joint member is axially displaced to the back side of the joint, the inside and the outside of the boot are communicated via the vent hole of the lip portion even if the lip portion contacts the outer peripheral surface of the shaft. Thus, the joint internal pressure can be suppressed from rising due to heat generation when the joint is rotating at high speed.

According to the present invention, when the inner joint member is axially displaced to the back side of the joint, the lip portion contacts the outer peripheral surface of the shaft, so that the lubricant filled inside the outer joint member leaks to the outside. It can prevent and secure sufficient sealing performance.

As a result, it is possible to prevent the external leakage of the lubricant and to suppress the rise in the internal pressure of the joint, to surely prevent the deformation of the boot and the breakage of the boot, and to provide a reliable long life sliding constant velocity universal joint. Can.

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal cross-sectional view which shows the whole structure of a double offset type constant velocity universal joint by embodiment of this invention. It is a cross-sectional view which shows the whole structure of the constant velocity universal joint of FIG. It is a longitudinal cross-sectional view which shows the state which the inner joint member axially displaced to the joint back side from the state of FIG. It is a longitudinal cross-sectional view which shows the state which the inner joint member further axially displaced to the joint back side from the state of FIG. It is a partial expanded sectional view which shows an example of a lip | rip part. It is a partial expanded sectional view which shows the other example of a lip | rip part. FIG. 2 is a cross-sectional view taken along the line PP of FIG. 1 and showing the vent groove. FIG. 2 is a cross-sectional view taken along the line QQ in FIG. 1 and is a cross-sectional view showing a notched semicircular vent. FIG. 2 is a cross-sectional view taken along the line QQ in FIG. 1 and is a cross-sectional view showing a notch rectangular vent. FIG. 2 is a cross-sectional view taken along the line QQ of FIG. 1 and is a cross-sectional view showing a notched V-shaped air vent; FIG. 2 is a cross-sectional view taken along the line QQ in FIG. 1 and is a cross-sectional view showing a through-hole-shaped vent hole. It is a partial expanded sectional view which shows the linear-shaped ventilation groove. It is a partial expanded sectional view which shows the ventilating groove of bending shape.

Embodiments of the sliding constant velocity universal joint according to the present invention will be described in detail below based on the drawings.

In the following embodiment, a slide is incorporated in a propeller shaft used in an automobile, and has a structure for connecting two shafts on the drive side and the driven side and transmitting rotational torque at a constant speed even when the two axes operate at an operating angle. The double offset constant velocity universal joint which is one of dynamic constant velocity universal joints is illustrated.

In the following embodiments, the case of application to a double offset constant velocity universal joint will be described, but other sliding constant velocity universal joints, for example, a cross groove constant velocity universal joint or a tripod constant velocity universal joint Is also applicable.

The sliding type constant velocity universal joint (hereinafter simply referred to as a constant velocity universal joint) of the embodiment shown in FIGS. 1 and 2 includes an outer joint member 11, an inner joint member 12, and a plurality of balls serving as torque transmitting members. 13 and the cage 14 are the main components.

The outer joint member 11 has a substantially cylindrical shape with both ends opened, and axially extending linear track grooves 15 are formed at a plurality of circumferential positions of the cylindrical inner circumferential surface 16 at equal intervals. In the inner joint member 12, linear track grooves 17 axially extending in pairs with the track grooves 15 of the outer joint member 11 are formed at a plurality of circumferential positions of the spherical outer peripheral surface 18 at equal intervals.

The ball 13 is interposed between the track groove 15 of the outer joint member 11 and the track groove 17 of the inner joint member 12 to transmit rotational torque. The cage 14 is interposed between the cylindrical inner peripheral surface 16 of the outer joint member 11 and the spherical outer peripheral surface 18 of the inner joint member 12 to hold the ball 13 accommodated in the pocket 19.

Although six balls 13 are illustrated in this embodiment, the number of balls 13 is arbitrary. Further, the shaft 21 is connected to the shaft hole 20 of the inner joint member 12 by spline fitting, and the retaining ring 22 prevents the shaft 21 from coming off.

The inner joint member 12, the balls 13 and the cage 14 are housed inside the outer joint member 11 to constitute an inner part 23. The inner component 23 is angularly and axially displaceable with respect to the outer joint member 11.

An annular groove 25 is provided on the inner peripheral surface of the open end portion 24 of the outer joint member 11, and a circlip 26 is fitted to the annular groove 25. With this structure, when the internal component 23 is displaced in the axial direction, the ball 13 interferes with the circlip 26 to restrict the axial displacement of the internal component 23 to prevent the slide over.

In the constant velocity universal joint having the above configuration, when an operating angle is applied between the outer joint member 11 and the inner joint member 12 by the shaft 21, the balls 13 held by the cage 14 are always at any operating angle. The constant velocity between the outer joint member 11 and the inner joint member 12 is maintained by being maintained within the bisecting plane of the operation angle.

In this constant velocity universal joint, the shaft 21 is angularly displaced and axially displaced relative to the outer joint member 11 by enclosing a lubricant 27 (indicated by a scattering point in the figure) such as grease inside the outer joint member 11. During the rotation operation, the lubricity at the sliding portion inside the joint is secured.

On the other hand, in order to prevent the leakage of the lubricant 27 enclosed inside the joint and to prevent the entry of foreign matter from the outside of the joint, one open end 24 of the outer joint member 11 is made of rubber or resin boot 28 and metal The boot adapter 29 is attached, and a metal seal plate 31 is attached to the other open end 30.

The boot 28 has a large diameter end 32 fixed by a boot adapter 29 attached to the open end 24 of the outer joint member 11 and a small diameter end fixed by a boot band 33 to a shaft 21 extending from the inner joint member 12. The large diameter end portion 32 and the small diameter end portion 34 are connected to each other, and the bending portion 35 is configured to be deformable at the time of axial displacement and angular displacement of the shaft 21.

The boot adapter 29 is composed of a proximal end 37 fitted to the outer peripheral surface of the open end 24 of the outer joint member 11 and a distal end 38 extending in the axial direction from the proximal end 37. The base end 37 is crimped and fixed to the groove 36 on the outer peripheral surface of the open end 24. The large diameter end 32 of the boot 28 is fixed to the tip 38 by caulking.

The seal plate 31 is formed of a disk-shaped plate portion 39 and a flange portion 40 which is extended in the axial direction by bending its outer peripheral edge. The seal plate 31 is attached to the inner peripheral surface of the open end 30 of the outer joint member 11 by press-fitting a flange 40.

In the constant velocity universal joint of this embodiment, a sectional tongue projecting toward the outer peripheral surface of the shaft 21 over the entire circumference on the inner peripheral surface of the bent portion 35 (the side close to the small diameter end portion 34) of the boot 28. A piece-like lip portion 41 is provided. The projection length of the lip portion 41 is preferably, for example, about 0.5 mm to 4 mm.

The lip portion 41 is not in contact with the outer peripheral surface of the shaft 21 when the inner part 23 including the inner joint member 12 is located at the joint center (joint center) (see FIG. 1). Contact with the outer peripheral surface of the shaft 21 when axially displaced to the side (see FIGS. 3 and 4). The joint center (joint center) means the axial position of the internal component 23 when the vehicle is parked on a flat road.

That is, as shown in the enlarged view of FIG. 1, when the internal part 23 is positioned at the center of the joint, the lip portion 41 is not in contact with the outer peripheral surface of the shaft 21, and the inner peripheral edge portion of the lip portion 41 and the outer periphery of the shaft 21 There is a gap m between it and the surface. The gap m is set to, for example, about 0.5 mm to 4 mm.

On the other hand, as shown by enlargement of FIG. 3 and FIG. 4, when the internal part 23 is axially displaced to the joint back side, the bent portion 35 of the boot 28 is deformed to be close to the outer peripheral surface of the shaft 21. The portion 41 contacts the outer peripheral surface of the shaft 21. FIG. 3 shows a state in which the inner part 23 has moved to a substantially central position of the outer joint member 11. 4 shows a state in which the inner part 23 has moved to the deepest position of the outer joint member 11. As shown in FIG.

In the constant velocity universal joint of this embodiment, when the internal part 23 is axially displaced to the back side of the joint (see FIGS. 3 and 4), the lubricant 27 filled inside the outer joint member 11 is deformed. Before the bent portion 35 of the boot 28 approaches and enters the small diameter end 34 side, the lip portion 41 contacts the outer peripheral surface of the shaft 21 by the deformation of the bent portion 35 of the boot 28.

The contact of the lip portion 41 can prevent the lubricant 27 from entering the small diameter end 34 of the boot 28. As a result, the lubricant 27 can be prevented from leaking to the outside, and sufficient sealing performance can be secured.

On the other hand, when the internal part 23 is located at the center of the joint (see FIG. 1), the lip portion 41 is not in contact with the outer peripheral surface of the shaft 21. Therefore, the gap m between the lip portion 41 and the outer peripheral surface of the shaft 21 The inside and the outside of the boot 28 communicate with each other through the.

The non-contact state of the lip portion 41 can suppress an increase in the joint internal pressure due to heat generation at the time of high speed rotation of the joint. In addition, deformation and wear and tear of the boot 28 can be prevented in advance.

Here, the formation position of the lip portion 41 may be other than the portion shown in FIG. 1, and when the internal part 23 is axially displaced to the joint back side, the outer periphery of the shaft 21 is deformed by the deformation of the bent portion 35 of the boot 28. It is sufficient if it is a site that can contact the surface. That is, as shown by the broken line in FIG. 1, it is possible to form the lip portion 41 as long as it is from the folded portion n where the stress load is small to the small diameter end portion 34.

Also, the lip 41 is brought into contact with the outer peripheral surface of the shaft 21 when the internal part 23 moves one-third or more of the axial displacement from the center of the joint to the deepest position (the state of FIG. 3). The formation position and the size of the part 41 are set. By this setting, even if the enclosed amount of the lubricant 27 is maximum, the lubricant 27 can be prevented from entering the small diameter end 34 side of the boot 28.

The inner part 23 is axially displaced from the center of the joint to the deepest position, and the lip portion 41 contacts the outer peripheral surface of the shaft 21 before the lubricant 27 enclosed in the outer joint member 11 contacts the boot 28. Thus, the lubricant 27 can be reliably prevented from invading the small diameter end 34 of the boot 28.

The lip portion 41 of this embodiment has a cross-sectional shape inclined toward the open end 24 (see FIG. 1) of the outer joint member 11 as shown in FIG. 5A, but as shown in FIG. The cross-sectional shape may be inclined toward the small diameter end 34 of

Further, in the constant velocity universal joint of this embodiment, since the propeller shaft rotates at high speed, the internal pressure of the joint is increased due to heat generation during high speed rotation, and the boot life is prevented from being reduced due to deterioration due to heat generation. Therefore, as shown in FIG. 1, the ventilation groove 42 which is minute to the extent that the lubricant 27 does not leak is provided on the inner peripheral surface (fixed portion by the boot band 33) of the small diameter end 34 of the boot 28.

The vent groove 42 has a structure in which a vent path surrounded by the outer circumferential surface of the shaft 21 is formed. As described above, by communicating the inside and outside of the boot 28 with the vent groove 42, it is possible to prevent the rise in joint internal pressure and the decrease in the boot life due to the heat radiation effect of the vent groove 42 at high speed rotation.

6 is a cross-sectional view taken along the line PP in FIG. In this embodiment, as shown in FIG. 6, the case where one ventilation groove 42 is provided along the circumferential direction of the small diameter end 34 of the boot 28 is illustrated, but in the circumferential direction of the small diameter end 34 of the boot 28. There may be more than one venting groove 42 along, the number being arbitrary.

7A to 7D are cross-sectional views taken along the line QQ in FIG. In the constant velocity universal joint of this embodiment, the vent hole 43 is provided in the inner peripheral edge portion which is the shaft contact portion of the lip portion 41. There are various possible forms of the vent holes 43, and the forms are illustrated in FIGS. 7A to 7D.

Specifically, the vent hole 43 has a notch semicircular shape as shown in FIG. 7A, a notch rectangular shape as shown in FIG. 7B, a notch V shape as shown in FIG. 7C, as shown in FIG. Through holes are possible.

As described above, by providing the vent holes 43 in the lip portion 41, even in the lip portion 41, the rise in internal pressure of the joint due to heat generation can be suppressed at high speed rotation of the joint, and deterioration due to heat generation reduces the boot life Can be prevented in advance.

As in the case of the ventilation groove 42 described above, in this embodiment, one vent hole 43 is provided along the circumferential direction of the lip portion 41 of the boot 28, but along the circumferential direction of the lip portion 41 of the boot 28. Two or more vents 43 may be provided, and the number is arbitrary.

Further, while the lip portion 41 is in contact with the outer peripheral surface of the shaft 21 and sealed while transitioning from the state of FIG. 3 to the state of FIG. it can.

On the other hand, as shown in FIG. 4, when the lubricant 27 comes in contact with the lip portion 41 as in the state where the inner component 23 is positioned at the deepest position of the outer joint member 11, the bent portion 35 of the boot 28 is The deformation becomes large and the air vent 43 of the lip portion 41 is closed.

Thus, although the lip portion 41 and the vent hole 43 are completely closed in the state of FIG. 4, the state in which the internal component 23 of FIG. 4 is positioned at the deepest position of the outer joint member 11 is long during operation. There is no influence on the rise in joint internal pressure because it does not occur for a while.

Therefore, even if the air vent 43 is formed, the lubricant 27 can be prevented from leaking to the outside, and sufficient sealing performance can be secured.

In this embodiment, the vent holes 43 of the lip portion 41 and the vent grooves 42 of the small diameter end portion 34 are formed in different phases (circumferential positions) in the circumferential direction of the shaft 21. For example, although the case where the vent groove 42 shown in FIG. 6 and the vent holes 43 shown in FIGS. 7A to 7D are formed in a phase shifted by 180 ° is illustrated, the amount of phase shift is arbitrary.

As described above, by forming the vent holes 43 of the lip portion 41 and the vent grooves 42 of the small diameter end portion 34 in different phases in the circumferential direction of the shaft 21, the amount of phase shift between the vent holes 43 and the vent grooves 42 can be obtained. Accordingly, adjustment of the joint internal pressure becomes possible.

The ventilation groove 42 has a linear shape formed along the axial direction of the shaft 21 as shown in an enlarged manner in FIG. 1 and FIG. 8. By forming such a straight ventilating groove 42 along the axial direction of the shaft 21, the ventilating groove 42 can be easily manufactured.

Further, as shown in FIG. 9, the ventilation groove 42 is an inner groove portion 44 formed along the axial direction of the shaft 21 and an intermediate groove formed along the circumferential direction of the shaft 21 continuously to the inner groove portion 44. The groove 45 and the outer groove 46 formed along the axial direction of the shaft 21 continuously to the intermediate groove 45 may have a bent shape.

By adopting such a configuration, even when the lubricant 27 reaches the ventilation groove 42, leakage of the lubricant 27 to the outside of the joint via the ventilation groove 42 can be easily suppressed. Although FIG. 9 exemplifies the case where the inner groove portion 44 and the outer groove portion 46 are formed in a phase shifted by 180 ° in the circumferential direction of the shaft 21, the shift amount of the phase is arbitrary.

The present invention is not limited to the embodiment described above, and it goes without saying that the present invention can be practiced in various forms without departing from the scope of the present invention, and the scope of the present invention is defined by And the meaning of equivalents described in the claims, and all changes within the range.

Claims

An outer joint member and an inner joint member transmitting rotational torque while allowing axial displacement and angular displacement between the outer joint member via a torque transmission member, and a lubricant is contained in the outer joint member. A sliding type constant velocity universal joint in which an end portion of a boot which seals and closes an opening of the outer joint member is mounted on a shaft extending from the inner joint member,
A lip portion which is not in contact with the outer peripheral surface of the shaft when the inner joint member is positioned at the center of the joint, and which contacts the outer peripheral surface of the shaft when the inner joint member is axially displaced to the joint back side A sliding type constant velocity universal joint provided on an inner circumferential surface of the boot.
The lip portion is in contact with the outer peripheral surface of the shaft by being deformed so that the bent portion of the boot approaches the outer peripheral surface of the shaft when the inner joint member is axially displaced to the rear side of the joint. The sliding type constant velocity universal joint according to Item 1.
The sliding constant velocity universal joint according to claim 1 or 2, wherein a vent groove communicating the inside and outside of the boot is provided on an inner peripheral surface of an end portion of the boot.
The sliding type constant velocity universal joint according to any one of claims 1 to 3, wherein at least one vent hole is provided at a shaft contact portion of the lip portion.