JPH1019054A - Elastic coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To coexist securing both of operation stability and vibration damping performance with lightening in weight and freely absorb the vibration and displacement in the axial direction. SOLUTION: The tip of a shaft 22 and a yoke 21 are connected to each other through a damping unit 6. The projected pieces 24 and 24 fixed to the tip of the shaft 22 is loosely engaged with the notches 25 and 25 which are provided in the yoke 21 mentioned above. An elastic material 29 and a sliding layer 30 are provided between the internal peripheral face of the outside wave form cylindrical section 32 of an out side sleeve 27 constituting the damping unit 26 and the outer peripheral face of the inside wave form cylindrical section 35 of an inside sleeve 28. Small torque is transmitted through the both sleeves 27 and 28 and the elastic material 29, and large torque is transmitted by the abutting of the projected pieces 24 and 24 and the notches 25 and 25. When transmitting torque, a load is applied to the elastic material 29 in the compression direction. Therefore, even if the thickness and hardness of the elastic material 29 that are required for maintaining the vibration damping performance constant, excellent operation stability can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION An elastic joint according to the present invention is incorporated, for example, into a universal joint which constitutes a steering device for a motor vehicle so that the movement of a steering wheel can be freely transmitted to a steering gear, and the vibration on the steering gear side is reduced. To prevent transmission.

[0002]

2. Description of the Related Art A steering apparatus for an automobile is configured to transmit a movement of a steering shaft which is rotationally driven by a steering wheel to a steering gear to impart a steering angle to front wheels. Usually, the steering shaft and the input shaft of the steering gear cannot be arranged on the same straight line. Therefore, a universal joint is provided between the steering shaft and the input shaft so that the movement of the steering wheel can be transmitted to the steering gear. In order to prevent the vibration transmitted from the wheels to the steering gear during driving of the car from further transmitting to the steering wheel and giving the driver discomfort, the universal joint has been provided with a vibration absorbing capability. Is being done. In order to provide the universal joint with the vibration absorbing capability, it is common practice to incorporate an elastic material such as rubber into the universal joint and to prevent transmission of vibration by the elastic material.

Conventionally, a universal joint functioning as such an elastic joint has been disclosed in JP-A-56-39325 (=).
French Patent Publication No. 2464404), 60-1847
Nos. 16-8, 60-215122-3, 61-201924, JP-A-54-82257, JP-A-5-83462, and 5-89964.
And Japanese Patent Laid-Open Publication No. 2614985. 9 to 11 show the structure described in Japanese Utility Model Laid-Open No. 5-89964.

A universal joint 1 incorporating this elastic joint is:
As shown in FIG. 9, the shaft 2, a first yoke 4 and a second yoke 5 that are externally fitted and fixed to a tip portion (the left end portion in FIGS. 9 to 10) of the shaft 2 via a buffer tube 3, A cross shaft 6 for connecting the second yoke 5 and the first yoke 4 is provided. As shown in FIGS. 10 to 11, a serration shaft portion 7 is formed at a portion of the tip end of the shaft 2 protruding from one end edge (the left end edge in FIG. 10) of the buffer cylinder 3. Then, the center hole 9 of the transmission piece 8 is
Serrations are engaged. Therefore, this transmission piece 8
The shaft 2 is fixed to the tip of the shaft 2.
Rotate with. Further, at two positions on the outer peripheral edge of the transmission piece 8 on the opposite side in the diameter direction, protruding pieces 10, 10 protruding outward in the diameter direction from the outer peripheral surface of the buffer cylinder 3 are integrally formed.

[0005] Among the constituent members of the elastic joint 1, the buffer cylinder 3 is formed in a cylindrical shape including an elastic material 11 such as rubber or elastomer. That is, in the shock-absorbing cylinder 3, an inner sleeve 12 and an outer sleeve 13 each made of metal and made in a cylindrical shape are arranged concentrically with each other. Then, the outer peripheral surface of the inner sleeve 12 and the inner peripheral surface of the elastic material 11 are joined by baking or bonding, and the inner peripheral surface of the outer sleeve 13 and the outer peripheral surface of the elastic material 11 are similarly joined. I have. The inner sleeve 12 is externally fitted and fixed to the tip of the shaft 2, and the outer sleeve 13 is provided on the first yoke 4.
4 internally fixed.

The first yoke 4 extends in the axial direction from a cylindrical portion 14 and a position opposite to the diametrical end of one end (left end in FIG. 9) of the cylindrical portion 14 in the axial direction (left-right direction in FIGS. 9 to 10). It has a pair of first arms 15. Then, first circular holes 16, 16 are formed concentrically with each other at the tips (left ends in FIGS. 9 to 10) of the first arms 15, 15. Further, the pair of first arms 15, 15 is positioned at a position diametrically opposite to one axial end of the cylindrical portion 14.
Notches 17, 17 are formed in portions deviating from the respective portions. The width dimension W of each of these notches 17, 17
Is larger than the width dimension w of the projecting pieces 10 and 10 of the transmission piece 8 (W> w). Then, in a state where the shaft 2 is assembled inside the first yoke 4, each of the protruding pieces 10, 10
Are loosely engaged with the insides of the notches 17 with a gap.

The second yoke 5 has a pair of second arms 18 provided separately from each other, and is fixedly connected to an end of another shaft 19. Each of the second arms 18
The second circular holes 20 are formed concentrically with each other at the tip end portions. The four ends of the cross shaft 6 are respectively provided with a pair of first and second circular holes 16, 2.
0, through a bearing such as a radial needle bearing,
It is rotatably supported.

The operation of the elastic joint 1 constructed as described above is as follows. When the vehicle is in a straight running state or when the rotational torque applied to the shaft 2 from the steering wheel is small, the projecting pieces 10 and 10 of the transmission piece 8 fixed to the tip of the shaft 2 The cutouts 17, 17 formed in the cylindrical portion 14 of FIG. 4 are located at the neutral position inside or slightly deviated from the neutral position. In each of these states, there is no direct contact between the cylindrical portion 14 and the transmission piece 8. Further, the small rotation torque is transmitted from the shaft 2 to the first yoke 4 via the buffer cylinder 3. In this case, the vibration transmitted from the wheel to the first yoke 4 via the steering gear, the another shaft 19, the second yoke 5, the cross shaft 6, and the like is transmitted by the elastic member 11 constituting the buffer cylinder 3. It is absorbed and does not reach the shaft 2.

On the other hand, when a large steering angle is applied to the front wheels, the shaft 2
When the rotational torque applied to the notch is large, the projecting pieces 10, 10 abut against the inner surfaces of the notches 17, 17. As a result, most of the rotational torque applied to the shaft 2 from the steering wheel is transmitted to the first yoke 4 via the transmission piece 8. In this state, the rotational torque transmitted via the buffer cylinder 3 is limited. Therefore, even when the rotational torque transmitted via the elastic joint 1 becomes large, no excessive force acts on the elastic member 11 constituting the buffer cylinder 3, and the elastic member 11 is not damaged.

[0010]

In the case of the conventional elastic joint constructed as described above, it has been difficult to attain both steering stability and vibration damping performance while at the same time reducing the size and weight. That is, in order to improve the torsional rigidity of the elastic member 11 in order to secure steering stability, it is necessary to increase the diameter of the elastic member 11 or increase the hardness of the elastic member 11.
However, in the case of the conventional structure shown in FIGS. 9 to 11, the diameter of the elastic material 11 is increased because the buffer cylinder 3 including the elastic material 11 is fitted and fixed inside the first yoke 4. It is difficult to improve the torsional rigidity. In addition, when the hardness of the elastic member 11 is increased, the vibration damping performance is deteriorated.

Further, when vibrations in the axial direction are applied between the shaft 2 and the first yoke 4, the performance of damping the vibrations is poor, and the vibrations in the axial direction are easily transmitted to the steering wheel side. . That is, when vibration in the axial direction is applied to the first yoke 4, the elastic member 11 provided between the outer peripheral surface of the inner sleeve 12 and the inner peripheral surface of the outer sleeve 13, which constitute the shock absorber cylinder 3, Is applied to the elastic member 11 to elastically deform it. However, since the rigidity of the elastic member 11 with respect to the force in this direction is large, the ability to absorb the vibration is poor. As described above, the vibration in the axial direction is generated from the first yoke 4 to the side of the steering wheel. Is easily transmitted to the shaft 2.

The other structures described in the above publications also have a poor ability to attenuate vibration in the axial direction or cannot cope with a case where it is desired to increase the amount of displacement in the axial direction. It is. The elastic joint of the present invention has been developed in view of such circumstances, and has a practical structure capable of securing both steering stability and vibration damping performance and reducing weight, and absorbing a large displacement in the axial direction. Is provided.

[0013]

An elastic joint according to the present invention comprises: an end of a rotatable shaft such as a steering shaft;
A cylindrical member that rotates with the rotation of the shaft, such as a part of a yoke that constitutes a universal joint, is connected so as to be able to absorb a slight displacement in the axial and rotational directions. Such an elastic joint of the present invention includes a protruding piece, a notch or a through hole, and a buffer unit. The protruding piece is
It is fixed to the end of the shaft so as to protrude radially outward from the outer peripheral surface of the shaft. Further, the notch or the through hole is formed at a portion of the end of the cylindrical member which is aligned with the projecting piece, and the projecting piece is loosely engaged with the inside thereof. Further, the buffer unit is provided between the outer peripheral surface of the end of the shaft and the outer peripheral surface of the tubular member. Further, the buffer unit includes an outer sleeve, an inner sleeve, an elastic material and a sliding layer. The outer sleeve is externally fitted and fixed to the outer peripheral surface of the end of the shaft. The inner sleeve is externally fitted and fixed to the outer peripheral surface of the tubular member. Further, the elastic material and the sliding layer are provided between the inner sleeve and the outer sleeve. or,
The outer sleeve includes an inner tubular portion, an outer corrugated tubular portion, and a connecting portion. The inner cylindrical portion is for externally fitting and fixing the outer sleeve to the end of the shaft. Also, the outer corrugated tube is concentric with the inner tube,
The shape in the circumferential direction is a waveform. Further, the connecting portion connects the edge of the outer corrugated tube and the edge of the inner tube. Further, the inner sleeve includes a fitting fixing portion and an inner corrugated tube portion. The fitting fixing portion is for fixing the inner sleeve to the cylindrical member. The inner corrugated tube portion is formed in the same phase as the outer corrugated tube portion, and is arranged inside the outer corrugated tube portion. Further, the elastic material and the sliding layer are provided between the inner peripheral surface of the outer corrugated tubular portion and the outer peripheral surface of the inner corrugated tubular portion. The sliding layer is provided so as to cover the outer peripheral surface of the elastic material, and is slidably contacted with the inner peripheral surface of the outer corrugated tube portion in the axial direction.

[0014]

The operation of transmitting the rotational force while preventing the transmission of vibration by the elastic joint of the present invention having the above-described structure is as follows. Even when transmitting torque,
When the torque to be transmitted is low torque, a compressive load is applied to the elastic material existing between the inner peripheral surface of the outer corrugated cylindrical portion and the outer peripheral surface of the inner corrugated cylindrical portion while applying a compressive load. The torque is transmitted via the. When the torque to be transmitted is low torque or when the torque is not transmitted, the elastic member prevents the transmission of vibration between the tubular member and the shaft.

In the case of the elastic joint according to the present invention, when transmitting the rotational force, the elastic material transmits the rotational force while receiving the force in the compression direction. The stiffness of an elastic material such as rubber, elastomer or the like is far greater for a force in the compression direction than for a force in the tension or shear direction. Therefore, in order to effectively attenuate the vibration,
Even if the thickness of the elastic material is increased or the hardness is reduced, the rotation force can be transmitted quickly (with good response) via the elastic material. Therefore, even if the vibration damping performance of the elastic joint is enhanced, the steering stability does not decrease.

Also, the vibration and displacement in the axial direction are absorbed by the sliding layer covering the outer peripheral surface of the elastic material sliding on the inner peripheral surface of the outer corrugated tube portion. The coefficient of friction between the outer peripheral surface of the sliding layer and the inner peripheral surface of the outer corrugated tube can be reduced irrespective of the presence of the elastic material. Therefore, based on the sliding between the outer peripheral surface of these sliding layers and the inner peripheral surface of the outer corrugated tube portion,
Absorption of the axial vibration and displacement can be effectively performed.
In addition, the amount of displacement that can be absorbed can be freely set regardless of the thickness and hardness of the elastic material, and the load required for displacement can be constant regardless of the amount of displacement that has occurred.

When the torque of the rotational force to be transmitted increases, the projecting piece fixed to the shaft abuts against the inner edge of the notch formed in the cylindrical member, so that the elastic material To transmit the rotational force that cannot be transmitted. Therefore, no excessive compressive stress is applied to the elastic material,
The durability of this elastic material can be sufficiently ensured.

[0018]

1 to 8 show a first embodiment of the present invention. In the present embodiment, an elastic joint 23 of the present invention is constituted by a yoke 21 of a universal joint constituting a steering device for an automobile and a shaft 22 attached to the yoke 21. The yoke 21 corresponds to a cylindrical member. That is, the structure of the present embodiment is configured such that the end of the shaft 22 that rotates based on the operation of the steering wheel and the yoke 21 that rotates with the rotation of the shaft 22 are slightly displaced in the axial direction and the rotational direction. It is connected so that it can be absorbed.

Such an elastic joint 23 of the present invention includes a pair of projecting pieces 24, 24 provided on the diametrically opposite side, a pair of notches 25, 25, and a buffer unit 26. Each of the protruding pieces 24 is attached to the tip of the shaft 22 (the left end in FIG. 1).
2 are fixed so as to protrude outward in the diametric direction from the outer peripheral surface. In this manner, the projecting pieces 24, 2
In order to fix 4, a member formed separately may be joined and fixed by welding, shrink fitting or the like, in addition to being integrally formed by forging, shaving, or the like.

The notches 25 are formed at the base edge of the yoke 21 (the right edge in FIG. 1).
4 and 24 are formed at the portions that match. The width of each of the notches 25, 25 is slightly larger than the width of the tip of each of the protruding pieces 24, 24. Therefore, the respective projecting pieces 24, 24 are loosely engaged with the insides of the respective notches 25, 25. As a result, each of the projecting pieces 24, 24
The shaft 22 and the yoke 21 are fixedly displaceable relative to each other in the rotational direction. Further, the buffer unit 26 is provided with the shaft 22.
And the outer peripheral surface of the yoke 21.

The cushioning unit 26 includes an outer sleeve 27 as shown in FIGS. 3 and 4, an inner sleeve 28 as shown in FIGS. 5 and 6, an elastic member 29 and a sliding member as shown in FIGS. And a layer 30. Of these, the outer sleeve 27
As shown in FIGS. 1 and 2, the shaft 22 is externally fitted and fixed to the outer peripheral surface of the distal end portion. The inner sleeve 28 is externally fitted and fixed to the outer peripheral surface of the yoke 21 so as to cover the cutouts 25, 25. Therefore, the engaging portion between each of the projecting pieces 24, 24 and the notches 25, 25 is
Exists diametrically inside. As a result, regardless of the presence of these engagement portions and the buffer unit 26, the elastic joint 23
In the axial direction can be reduced. Further, the elastic material 29 and the sliding layer 30 are provided between the inner sleeve 28 and the outer sleeve 27.

The outer sleeve 27 is formed by integrally forming a metal plate having sufficient rigidity, such as a steel plate, by press working, drawing work, or the like. It has a corrugated tube part 32 and a connecting part 33. The inner cylindrical portion 31 of the outer sleeve 27 is
Is formed in a cylindrical shape so as to be externally fitted to the tip of the shaft 22, and the inner diameter in the free state is slightly smaller than the outer diameter of the tip of the shaft 22. Therefore, the inner cylindrical portion 31 is externally fitted and fixed to the distal end portion of the shaft 22 by interference fit. The outer corrugated tubular portion 32 is concentric with the inner tubular portion 31 and has an end face shape of chrysanthemum by making a shape extending in a circumferential direction into a waveform. Further, the connecting portion 33 is connected to the shaft 2
2, the outer corrugated cylindrical portion 3
2 and the base edge of the inner cylindrical portion 31 are continuous with each other.

The inner sleeve 28 is also formed integrally by subjecting a metal plate having sufficient rigidity, such as a steel plate, to plastic working such as pressing and drawing.
A fitting fixing portion 34 and an inner corrugated tube portion 35 are provided. The fitting fixing portion 34 is provided on one half in the axial direction of the inner sleeve 28 (the left half of FIGS. 1, 5, and 7) for externally fixing the inner sleeve 28 to the yoke 21. The inner diameter in the free state is slightly smaller than the outer diameter of the yoke 21. Therefore, the fitting fixing portion 34 is externally fitted and fixed to the yoke 21 by interference fitting. The inner corrugated tube 35 is provided in the other half of the inner sleeve 28 in the axial direction (the right half in FIGS. 1, 5, and 7), and has the same phase as the outer corrugated tube 32. Formed and arranged inside the outer corrugated tube portion 32. Therefore,
Between the inner peripheral surface of the outer corrugated tube portion 32 and the outer peripheral surface of the inner corrugated tube portion 35, a cylindrical space having a corrugated shape in the circumferential direction is formed. The thickness of the cylindrical space is substantially constant in the circumferential direction.

Further, the elastic material 29 and the sliding layer 30 are
The inner peripheral surface of the outer corrugated tube portion 32 and the inner corrugated tube portion 35
Is provided in the above-mentioned cylindrical space between the outer peripheral surface and the outer peripheral surface. The elastic member 29 is made of rubber, elastomer, or the like, and its inner peripheral surface is bonded to the outer peripheral surface of the inner sleeve 28 by baking, bonding, or the like. On the other hand, the sliding layer 30 is made of a slippery synthetic resin such as polyamide resin (nylon) and polytetrafluoroethylene resin (PTFE), and covers the entire outer peripheral surface of the elastic member 29.
When the elastic material 29 is formed on the outer peripheral surface of the inner sleeve 28, the synthetic resin constituting the sliding layer 30 is heated by vulcanization of the elastic material 29 or the like. It spreads evenly over the entire outer peripheral surface. Therefore, it is easy to secure the accuracy (shape (roughness) accuracy and dimensional accuracy) of the surface of the sliding layer 30. Such a sliding layer 3
Reference numeral 0 abuts on the inner peripheral surface of the outer corrugated tubular portion 32 slidably in the axial direction.

The operation of the elastic joint 23 configured as described above is as follows. When the vehicle is in a straight-ahead state, or when the rotational torque applied to the shaft 22 from the steering wheel is small, a pair of projecting pieces 24, 24 fixed to the tip of the shaft 22 The pair of cutouts 25, 25 formed at the edge portions are located at the inner neutral position or a position slightly deviated from the neutral position. In each of these states, there is no direct contact between the yoke 21 and the projecting pieces 24, 24 fixed to the shaft 22. Further, the small rotation torque is transmitted from the shaft 22 to the yoke 2 via the buffer unit 26.
1 is transmitted. In this case, the vibration transmitted from the wheels to the yoke 21 via the steering gear, the components of the universal joint and the like is absorbed by the elastic member 29 constituting the buffer unit 26 and does not propagate to the shaft 22.

When transmitting the rotational force, the elastic member 29
Transmits this rotational force while receiving a force in the compression direction. That is, when the outer sleeve 27 and the inner sleeve 28 constituting the buffer unit 26 tend to be relatively displaced in the rotation direction, the elastic material 29 sandwiched between the peripheral surfaces of the two sleeves 27 and 28 becomes Outer sleeve 2
7 and one circumferential side of a plurality of ridges projecting radially inward from the inner peripheral surface of the inner sleeve 7 and the plurality of ridges projecting diametrically outward from the outer peripheral surface of the inner sleeve 28. It is elastically compressed with one side. The stiffness of the elastic material 29 such as rubber, elastomer, or the like is much greater in the case of the force in the compression direction than in the case of the force in the tensile direction or the shear direction. Therefore, even if the thickness of the elastic member 29 is increased or the hardness is reduced in order to effectively attenuate the vibration, the transmission of the rotational force via the elastic member 29 is quickly performed. Can be done. Therefore, even if the vibration damping performance of the elastic joint is enhanced, the steering stability does not decrease. In other words, sufficient vibration damping performance can be ensured, and steering response can be improved.

The vibration and displacement in the axial direction are absorbed by the sliding layer 30 covering the outer peripheral surface of the elastic member 29 sliding in the axial direction with respect to the inner peripheral surface of the outer corrugated tube portion 32. I do. The coefficient of friction between the outer peripheral surface of the sliding layer 30 and the inner peripheral surface of the outer corrugated tubular portion 32 made of a slippery synthetic resin such as polyamide resin and polytetrafluoroethylene is independent of the presence of the elastic material 29. Can be smaller. Further, it is easy to secure the accuracy of the outer peripheral surface of the sliding layer 30 and to set the contact pressure between the outer peripheral surface of the sliding layer 30 and the inner peripheral surface of the outer corrugated tube portion 32 to a desired value. Therefore, these sliding layers 30
The vibration and displacement in the axial direction can be effectively absorbed based on the sliding between the outer peripheral surface and the inner peripheral surface of the outer corrugated tube portion 32. In addition, by securing the axial dimension of the outer corrugated tube portion 32, the amount of displacement that can be absorbed can be freely set regardless of the thickness and hardness of the elastic member 29, and regardless of the amount of displacement that has occurred. The load required for displacement can be made constant.
Therefore, the present invention can be applied to a portion having a large amount of displacement in the axial direction, such as a telescopic steering column.

On the other hand, when the rotational torque applied to the shaft 22 from the steering wheel is large, such as when a large steering angle is applied to the front wheels, each of the projecting pieces 24,
24 abuts against the inner surface of each notch 25, 25.
As a result, the shaft 22 is displaced from the steering wheel.
A large part of the rotational torque applied to the yoke 21 is transmitted to the yoke 21 via the protruding pieces 24, 24.
In this state, the rotational torque transmitted via the elastic member 29 constituting the buffer unit 26 is limited. Therefore, even when the rotational torque transmitted via the elastic joint 23 is increased, no excessive force acts on the elastic member 29 constituting the buffer unit 26, and
Damage to the elastic member 29 can be prevented. The portion formed on the cylindrical member such as the yoke 21 for loosely engaging the protruding pieces 24, 24 may be a through hole instead of the notches 25, 25. However, in this case, a pin is press-fitted into the fitting hole formed in the diametrical direction at the distal end of the shaft 22 through the through-hole, and both ends of the pin are engaged with the through-hole as projections. Enables assembly.

[0029]

Since the elastic joint of the present invention is constructed and operates as described above, it is possible to ensure both steering stability and vibration damping performance while reducing the weight. In addition, since displacement and vibration in the axial direction can be effectively absorbed, good vibration damping performance can be obtained over a wider range. Further, since each of the constituent members can be efficiently processed, it is possible to contribute to a reduction in manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a cut-away side view showing an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view of an outer sleeve.

FIG. 4 is a view seen from the left side of FIG. 3;

FIG. 5 is a sectional view of the inner sleeve.

FIG. 6 is a view seen from the right side of FIG. 5;

FIG. 7 is a cross-sectional view showing a state where an elastic material and a sliding layer are connected to an inner sleeve.

FIG. 8 is a view seen from the right side of FIG. 7;

FIG. 9 is a perspective view showing an example of a conventional structure.

FIG. 10 shows the cross axis and the second yoke omitted,
BB sectional drawing of FIG.

FIG. 11 is a view seen from the left side of FIG. 10;

[Explanation of symbols]

 Reference Signs List 1 universal joint 2 shaft 3 buffer cylinder 4 first yoke 5 second yoke 6 cross shaft 7 serration shaft portion 8 transmission piece 9 center hole 10 projecting piece 11 elastic material 12 inner sleeve 13 outer sleeve 14 cylindrical portion 15 first arm 16 first One circular hole 17 Notch 18 Second arm 19 Another shaft 20 Second circular hole 21 Yoke 22 Shaft 23 Elastic joint 24 Projection piece 25 Notch 26 Buffer unit 27 Outer sleeve 28 Inner sleeve 29 Elastic material 30 Sliding layer 31 Inner cylinder Part 32 Outer corrugated tubular part 33 Connecting part 34 Fitting and fixing part 35 Inner corrugated tubular part

Claims (1)

[Claims] An elastic joint for connecting an end of a rotatable shaft and a cylindrical member that rotates with the rotation of the shaft so as to absorb a slight displacement in an axial direction and a rotational direction, A protruding piece fixed to the end of the shaft in a state of protruding diametrically outward from the outer peripheral surface of the shaft, and a portion aligned with the protruding piece at an end edge of the tubular member; A notch or a through hole for loosely engaging the protruding piece on the inner side thereof, and a buffer unit provided between the outer peripheral surface of the end of the shaft and the outer peripheral surface of the cylindrical member are provided. An outer sleeve fixed to the outer peripheral surface of the end of the shaft, an inner sleeve fixed to the outer peripheral surface of the tubular member, and an elastic member provided between the inner sleeve and the outer sleeve. Material and sliding layer, of which The outer sleeve has an inner cylindrical portion for externally fitting and fixing to the end of the shaft, an outer corrugated cylindrical portion concentric with the inner cylindrical portion and having a waveform extending in the circumferential direction, and an outer corrugated cylindrical portion. And a connecting portion for connecting an end edge of the inner cylindrical portion to an end edge of the inner cylindrical portion. The inner sleeve is the same as the fitting fixing portion for externally fitting and fixing to the cylindrical member, and the outer corrugated cylindrical portion. An inner corrugated tubular portion formed in a phase waveform and disposed inside the outer corrugated tubular portion, wherein the elastic material and the sliding layer are provided on an inner peripheral surface of the outer corrugated tubular portion and the inner corrugated tubular portion. And the sliding layer is provided so as to cover the outer peripheral surface of the elastic material, and slidably abuts the inner peripheral surface of the outer corrugated tube portion in the axial direction. Have elastic joints.