JPH08133097A - Elastic shaft coupling - Google Patents

Abstract

PURPOSE: To secure such a structure as being compact in size and excellent in rigidity and also no difference in characteristics due to a direction of rotation. CONSTITUTION: Both sectional forms of an inner cylinder 14 externally fitted and clamped to the tip part of a shaft 15 and an outer cylinder 19 internally fitted and clamped to a tubular part of a yoke 20 are of oval in either case. In addition, two outward flat surfaces 12 and 12 of an outer circumferential surface of the inner cylinder 14 and two inner flat surfaces 13 and 13 of an inner circumferential surfaces of the outer cylinder 19 are opposed to each other. Moreover, an elastic material 26 is installed in space between both outer and inner circumferential surfaces. Likewise, at axial ends of the inner flat surface 13 and 13, two projections 24 and 24 are projectingly formed in both ends in the cross direction toward the said outward flat surfaces 12 and 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The elastic shaft joint according to the present invention is used in a state where it is incorporated in a steering device of an automobile in order to prevent the vibration of the wheel from being transmitted to the steering wheel.

[0002]

2. Description of the Related Art When vehicle vibrations are transmitted to a steering wheel while a vehicle is running, the driver who operates the steering wheel feels uncomfortable. For this reason, conventionally, an elastic shaft coupling is provided in the intermediate portion of the steering shaft to prevent the vibration from being transmitted to the steering wheel.

For example, FIGS. 7 to 9 show Japanese Patent Publication No. 54-9768.
The structure described in the publication is shown. The movement of the steering wheel 1 is transmitted to the input shaft 6 of the steering gear 5 via the steering shaft 2, the universal joint 3, the intermediate shaft 4, and the universal joint 3. In the case of the structure described in this publication, the intermediate shaft 4 is an elastic shaft coupling 7 as shown in detail in FIGS.

This elastic shaft joint 7 is provided with an outer cylinder 8 and a shaft 9 whose peripheral surfaces facing each other are triangular in cross section. The elastic member 10 is provided between the inner peripheral surface of the outer cylinder 8 and the outer peripheral surface of the shaft 9 in an elastically compressed state. Transmission of the rotational force between the universal joints 3 provided at both ends is performed via the elastic member 10, but vibration is absorbed by the elastic member 10.

Further, in Japanese Utility Model Publication No. 58-50105,
An elastic shaft coupling 7a as shown in FIGS. 10 to 12 is described. The elastic shaft coupling 7a includes an outer cylinder 8a and a shaft 9 whose peripheral surfaces facing each other have a three-star cross section.
a. The elastic members 10a and 10b are provided between the inner peripheral surface of the outer cylinder 8a and the outer peripheral surface of the shaft 9a while being elastically compressed. In addition, a part of both the peripheral surfaces is made closer than other parts, and no elastic material is provided in this part. In the case of such an elastic shaft coupling 7a, low torque torque is transmitted through the elastic members 10a and 10b, and high torque torque is transmitted at a portion where the elastic member is not provided. This is done by directly contacting the two peripheral surfaces. Vibration is absorbed by the elastic members 10a and 10b in a state where high torque torque is not transmitted.

Further, Japanese Utility Model Publication No. 4-69283 discloses an elastic shaft coupling 7b as shown in FIGS. The elastic shaft coupling 7b has an outer cylinder 8b and a shaft 9b whose peripheral surfaces facing each other are oval in cross section.
And an elastic member 10c and a sleeve 11 which are interposed between the peripheral surfaces of the both members 8b and 9b. That is, a part of the outer peripheral surface of the shaft 9b is a pair of outer flat surfaces 12 and 12 parallel to each other, and a part of the inner peripheral surface of the outer cylinder 8b is a pair of inner flat surfaces parallel to each other. Surfaces 13 and 13 are used. Further, by engaging the inner peripheral surface of the outer cylinder 8b with a non-circular stopper 30 mounted on a part of the shaft 9b which is separated from the elastic member 10c, it is possible to prevent over-rotation and removal. There is. In the case of such an elastic shaft coupling 7b,
The low torque torque is transmitted through the elastic member 10c which is elastically compressed between the outer flat surfaces 12 and 12 and the inner flat surfaces 13 and 13, and the high torque torque is transmitted. ,
This is performed at the engaging portion of the non-circular stopper 30 where the elastic material 10c is not provided. Vibration is absorbed by the elastic material 10c in a state where high torque torque is not transmitted.

Further, Japanese Utility Model Publication No. 63-35896 discloses that
An elastic shaft coupling 7c as shown in FIGS. 15 to 16 is described. The elastic shaft coupling 7c is provided between the inner peripheral surface of the circular portion of the outer cylinder 8c and the outer peripheral surface of the circular portion of the shaft 9c.
0d is provided, and a part of the outer cylinder 8c in the axial direction and a part of the shaft 9c in the axial direction are non-circularly engaged as shown in FIG. In the case of such an elastic shaft coupling 7c, low torque torque is transmitted through the elastic member 10d, and high torque torque is transmitted at the non-circular engagement portion. The vibration is absorbed by the elastic material 10d in the state where the high torque torque is not transmitted.

[0008]

The conventional elastic shaft coupling constructed and operated as described above has the following points to be solved. First, in the case of the structure of the first example shown in FIGS. 8 to 9, even when high torque torque is transmitted, the elastic material 10 receives all the torque. Therefore, this elastic material 1
To ensure the durability of 0, the cross-sectional shape is triangular,
Alternatively, it is necessary to increase the axial length to increase the area of the elastic material 10 that is compressed when the rotational force is transmitted. It is not preferable to make the cross-section into a triangular shape because the machining work is complicated and the cost is high, and the axial length is large and the cost is high.

In the case of the structure of the second example shown in FIGS. 10 to 12, the outer cylinder 8a and the shaft 9a have complicated shapes,
The manufacturing work of each of the members 8a and 9a becomes troublesome, and the cost also rises. Also, when transmitting high torque torque,
Since the contact portion between the outer cylinder 8a and the shaft 9a becomes long,
Vibration is easily transmitted between the outer cylinder 8a and the shaft 9a, and the sound insulation (vibration absorption) performance of the elastic shaft coupling 7a is insufficient during high torque transmission.

Further, in the case of the structure of the third example shown in FIGS. 13 to 14, a portion where the elastic material 10c is provided between the inner peripheral surface of the outer cylinder 8b and the outer peripheral surface of the shaft 9b, and these members. 8
The non-circular engagement portion that restricts relative rotation between b and 9b is provided axially offset and independent of each other. Therefore, the manufacturing and assembling work of each member 8b and 9b is troublesome, and the manufacturing cost increases. In addition, the amount of rotation from the neutral position until the non-circular engagement portion is engaged is likely to be different in both directions due to manufacturing errors or assembly errors of the members 8b and 9b.

Further, in the case of the structure of the fourth example shown in FIGS. 15 to 16, the elastic member 10d has a cylindrical shape, and a load in the shearing direction is applied to the elastic member 10d when transmitting a torque of low torque. While transmitting. An elastic material such as rubber has a low rigidity with respect to a load in the compression direction and a rigidity with respect to a load in the shear direction (it is easily elastically deformed by the load in the shear direction). Therefore, in the case of the structure of the fourth example, the elastic members 10a-10a
As compared with the structures of the first to third examples in which the rotational force is transmitted while applying a load in the compression direction to c, the rigidity is low and the operation feeling of the steering wheel is reduced.

In addition to this, as the elastic shaft coupling, those described in, for example, Japanese Utility Model Laid-Open Nos. 56-152771, 64-31217 and 59-29147 are known. Of these, the actual development Sho 56-15277
In JP-A-1 and JP-B-59-29147, there is a structure in which an outer cylinder and a shaft, which have oval cross-sections facing each other, are combined with each other through an elastic material. A technique is disclosed in which the volume of the elastic material is increased by making it concave, and the vibration absorbing performance is improved while ensuring the rotation amount limiting function of the peripheral surface.
However, in the case of the structures described in Japanese Utility Model Publication No. 56-152771 and Japanese Utility Model Publication No. 59-29147, it is not always possible to secure a sufficient volume of the elastic material,
In some cases, sufficient vibration absorption performance may not be obtained. Further, since displacement prevention in the axial direction between the outer cylinder and the shaft depends only on the frictional force acting between the outer peripheral surface of the elastic material and the inner peripheral surface of the outer cylinder, the displacement prevention effect is not always sufficient. . Furthermore,
In the case of the structure described in Japanese Utility Model Laid-Open No. 64-31217, as in the case of the structure of the fourth example shown in FIGS. 15 to 16, the elastic material is cylindrical and the rotational force of low torque is low. At the time of transmission, since transmission is performed while applying a load in the shearing direction to this elastic material, the rigidity is low and the operation feeling of the steering wheel is reduced. The elastic shaft coupling of the present invention was invented in view of such circumstances.

[0013]

The elastic shaft coupling of the present invention comprises:
Similar to the conventional elastic shaft joint described in Japanese Utility Model Laid-Open No. 4-69283, an inner member having an outer peripheral surface having a part as an outer flat surface and an inner member having a part as an inner flat surface. An outer member having a surface, and an elastic material provided between the outer peripheral surface of the outer member and the outer peripheral surface of the inner member.

Particularly, in the elastic shaft coupling of the present invention, at least one of the inner flat surface and the outer flat surface has a widthwise end portion in the axial direction at the widthwise end portion of the flat surface. Form a protrusion that protrudes toward another flat surface facing each other.

[0015]

With the elastic shaft coupling of the present invention constructed as described above, the action of transmitting the rotational force while preventing the transmission of vibration is as follows. Even if the rotational force is transmitted, if the rotational force to be transmitted is low torque, the elastic material existing between the inner flat surface and the outer flat surface is loaded with the elastic force while applying the load in the compression direction. Rotational force is transmitted through the material. In this way, when the torque to be transmitted is a low torque and when the torque is not transmitted, the elastic material surely prevents the vibration transmission between the inner member and the outer member. Further, when the torque of the rotational force to be transmitted becomes large, the protrusion formed on one flat surface presses the other flat surface directly or through a thin elastic material layer, and To communicate. At this time, a compressive load is not applied to a part of the elastic material, which is separated from the protruding portion, in many parts. Therefore, the durability of the elastic material that substantially absorbs vibration is sufficiently ensured.

[0016]

1 to 3 show a first embodiment of the present invention. The inner cylinder 14 which is the inner member is made of a metal plate such as steel.
The cross-sectional shape is formed into an oval tubular shape. A part of the outer peripheral surface of the inner cylinder 14 is a pair of outer flat surfaces 12, 12 parallel to each other. Such an inner cylinder 14 is externally fitted and fixed to the tip of a shaft 15 that constitutes a universal joint so as to prevent rotation with respect to the shaft 15 and displacement in the axial direction (the left-right direction in FIG. 1). That is, a mounting portion 16 having a diameter smaller than that of the proximal portion is formed at the tip portion (left end portion in FIG. 1) of the shaft 15. This mounting part 16
Has an outer peripheral surface shape and size that allows the inner cylinder 14 to be fitted onto the outer cylinder without rattling, and has an axial length slightly larger than the axial length of the inner cylinder 14. A step portion 17 is formed at the boundary between the mounting portion 16 and the portion near the base end. When the inner cylinder 14 is externally fitted to the mounting portion 16 as described above, one end edge (the right end edge in FIG. 1) of the inner cylinder 14 is abutted against the step portion 17. Further, at the tip portion (left end portion in FIG. 1) of the mounting portion 16 that protrudes from the other end edge (left end edge in FIG. 1) of the inner cylinder 14, this portion should be caulked outward in the diametrical direction. The engaging portion 18 is formed by this, and the other end edge of the inner cylinder 14 is suppressed by the engaging portion 18.

As described above, around the inner cylinder 14 fixed to the outer peripheral surface of the distal end portion of the shaft 15, the outer cylinder 19 is formed of a metal plate such as steel and has an oval cross section.
Has been arranged. Then, a part of the inner peripheral surface of the outer cylinder 19 is formed as a pair of parallel inner flat surfaces 13, 13. Such an outer cylinder 19 is used for the yoke 2 which constitutes a universal joint.
It is internally fitted and fixed to the tubular portion 21 formed at the base end portion of 0.
In the case of the illustrated embodiment, one end edge (the left end edge in FIG. 1) of the outer cylinder 19 is formed on the step portion 22 formed on the inner peripheral surface of the cylinder portion 21.
When the outer cylinder 19 is brought into contact with the yoke 20
It is prevented from shifting to the tip side (left side in FIG. 1) of the.
Further, the opening end edge of the cylindrical portion 21 is bent inward in the diametrical direction to form bent edges 23. The bent edges 23, 23 are engaged with the recesses 25, 25 formed on the outer peripheral surface side of the outer cylinder 19 in order to form the protrusions 24, 24 described below. The engagement of the recesses 25, 25 with the bent edges 23, 23 prevents the outer cylinder 19 from slipping out of the cylinder 21.

The inner flat surfaces 13, 13 forming the inner peripheral surface of the outer cylinder 19 are axially partly (right part in FIG. 1) at widthwise end parts (left and right end parts in FIG. 3) respectively. Protruding portions 24, 24 that project inward in the diametrical direction are formed. Then, the inner peripheral side surfaces of the respective protruding portions 24, 24 are brought close to the outer flat surfaces 12, 12 which the respective inner flat surfaces 13, 13 face. The outer cylinder 19 and the inner cylinder 14 as described above are
Elastic members 26 such as rubber are provided concentrically with each other and between the inner peripheral surface of the outer cylinder 19 and the outer peripheral surface of the inner cylinder 14. still,
The inner and outer peripheral surfaces of the elastic member 26, the inner peripheral surface of the outer cylinder 19 and the outer peripheral surface of the inner cylinder 14 are baked as necessary.

With the elastic shaft coupling of the present invention constructed as described above, the action of transmitting the rotational force while preventing the transmission of vibration is as follows. The shaft 15 and the yoke 2
When the rotational force is not transmitted between the elastic members 26 and 0, the elastic member 26 is compressed substantially uniformly over the entire circumference.
Further, even when the rotational force is transmitted, if the rotational force to be transmitted is low torque, the inner flat surfaces 13, 1, 1
3 and the elastic material 26 existing between the outer flat surfaces 12, 12.
The rotational force is transmitted through the elastic material 26 while applying a load in the compression direction to a part of the. Further, when the torque of the rotational force to be transmitted becomes large, a total of four protrusions 24, 24 formed on the inner flat surfaces 13, 13 cause the outer flat surfaces 12, 12 to move. , The elastic force is strongly pressed through the thin layer of the elastic material 26 to transmit the rotational force. At this time, a large compressive load is not applied to a part of the elastic member 26 that is out of the protrusions 24, 24 in many parts. Therefore, the elastic material 26 that substantially absorbs vibrations
The durability of is sufficiently secured. Each protrusion 24, 24
Since a large load is applied to the thin layer portion of the elastic material 26 existing between the inner peripheral side surface and the outer flat surfaces 12, 12, it is difficult to ensure the durability of this portion. However, even if the elastic material 26 in this portion is damaged, it does not substantially affect the function of the elastic shaft coupling.

In the illustrated embodiment, the inner cylinder 14 constituting the elastic shaft coupling is prevented from being displaced with respect to the shaft 15 by the step portion 17 and the locking portion 18. Also, the outer cylinder 19 which also constitutes the elastic shaft coupling is prevented from being displaced with respect to the yoke 20 by the step portion 22 and the bent edge 23. Therefore, the displacement prevention fixing of the entire elastic shaft joint is surely performed.

Next, FIG. 4 shows a second embodiment of the present invention. In the case of this embodiment, the inner flat surface 1 of the outer cylinder 19
Protruding portions 24a, 24a having a U-shaped cross section are formed at both widthwise end portions of 3, 13. Then, the distal end portions of these protruding portions 24a, 24a are connected to the outer flat surface 1 of the inner cylinder 14.
It is close to 2 and 12. The configuration and operation of the other parts are similar to those of the first embodiment described above.

Next, FIG. 5 shows a third embodiment of the present invention. In the case of the present embodiment, instead of omitting the inner cylinder 14 (FIGS. 1 to 4), the inner peripheral surface of the elastic material 26 is directly baked on the outer peripheral surface of the tip portion of the shaft 15. That is, in the case of this embodiment, the shaft 15 functions as an inner member. Of course, the outer peripheral surface of the distal end portion of the shaft 15 has an oval cross section, and a pair of outer flat surfaces 12 parallel to each other are provided.
12 are provided. The configuration and operation of the other parts are similar to those of the first embodiment described above.

Next, FIG. 6 shows a fourth embodiment of the present invention. In the case of the present embodiment, between the shaft 15a forming the universal joint and the inner cylinder 14a forming the elastic shaft joint,
A so-called collapsible structure is provided that shortens the overall length when a strong impact force is applied. For this reason, in the case of the present embodiment, the total length of the inner cylinder 14a is made larger than the total length of the outer cylinder 19, and one or two pieces are provided in a part of the inner cylinder 14a protruding from the outer cylinder 19. The individual through holes 27 are formed.
Further, a concave groove 28 is formed over the entire circumference in a portion of the outer peripheral surface of the shaft 15a aligned with the through hole 27. Then, a synthetic resin 29 is injected and solidified in the groove 28. Normally, this synthetic resin 29 is
Due to the frictional force acting between the inner peripheral surface of a and the inner peripheral surface of the inner cylinder 14a
And the shaft 15a are prevented from moving in the axial direction.
When a strong impact force is applied in the axial direction, the synthetic resin 29 slides on the inner peripheral surface of the inner cylinder 14a, and the inner cylinder 14a and the shaft 15a are allowed to shift in the axial direction. . The present embodiment is characterized in that such a collapsible structure is added, and the structure and operation of the elastic shaft coupling are the same as those of the first embodiment described above.

In each of the illustrated embodiments, the inner cylinders 14 and 1 are
4a (or the shaft 15) and the outer cylinder 19 are formed on the inner flat surfaces 13 and 13 with protrusions 24 and 24a which function as stoppers that limit the amount of rotation of the inner flat surface 13. , 13 or in combination with the inner flat surfaces 13, 13, the outer flat surfaces 12, 12 may be formed with protrusions that project diametrically outward. Further, instead of omitting the outer cylinder 19, the outer peripheral surface of the elastic material 26 is connected to the cylindrical portion 2 of the yoke 20.
It is also possible to directly bake it on the inner peripheral surface of No. 1 and make this cylindrical portion 21 function as an outer member.

[0025]

Since the elastic shaft joint of the present invention is constructed and operates as described above, the following effects (1) to (4) can be obtained at the same time. It is possible to mold the elastic material between both the inner and outer members, and it is possible to secure sufficient dimensional accuracy such as the distance between the protrusion that functions as a stopper and the mating surface. For this reason, the amount of rotation limited by the protrusion does not easily differ depending on the rotation direction. Since the protrusion functioning as a stopper is provided only in a part in the axial direction and the width direction, it is difficult to transmit vibration between the inner member and the outer member through the protrusion, and the vibration preventing function can be sufficiently increased. Excessive compressive stress is not applied to most of the elastic members provided between the inner member and the outer member except for the portion facing the protruding portion. Therefore, the durability of the elastic material that substantially absorbs vibration can be sufficiently ensured. Since the durability of the elastic material can be sufficiently ensured, it is not necessary to increase the axial dimension of the elastic shaft coupling or use a member having a triangular cross section. As a result, it is possible to obtain a small-sized and lightweight elastic shaft coupling that can be easily manufactured at low cost. It is possible to easily and reliably prevent the outer member and the inner member from slipping off from each other. As a result, the reliability of the elastic shaft coupling mounting portion can be improved. As a whole of these, it is possible to obtain an elastic shaft joint that is small in size, has a high vibration preventing function, and has high torsional rigidity at low cost.

[Brief description of drawings]

FIG. 1 is a partially cut side view showing a first embodiment of the present invention.

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

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a view similar to FIG. 3, showing a second embodiment of the present invention.

FIG. 5 is a partially cut side view showing a third embodiment of the present invention.

FIG. 6 is a partially cut side view showing the fourth embodiment.

FIG. 7 is a schematic side view of a steering device incorporating an elastic shaft coupling.

FIG. 8 is a partially cut side view showing a first example of a conventional elastic shaft coupling.

9 is a sectional view taken along line CC of FIG.

FIG. 10 is a side view showing a second example of a conventional elastic shaft coupling.

FIG. 11 is an exploded perspective view showing a state in which a part is also cut.

FIG. 12 is an enlarged DD sectional view of FIG.

FIG. 13 is a vertical sectional side view showing a third example of a conventional elastic shaft coupling.

14 is a cross-sectional view taken along line EE of FIG.

FIG. 15 is a partially cut side view showing a fourth example of a conventional elastic shaft coupling.

16 is a cross-sectional view taken along the line FF of FIG.

[Explanation of symbols]

 1 Steering Wheel 2 Steering Shaft 3 Universal Joint 4 Intermediate Shaft 5 Steering Gear 6 Input Shaft 7, 7a, 7b 7c Elastic Shaft Joint 8, 8a, 8b, 8c Outer Cylinder 9, 9a, 9b, 9c Shaft 10, 10a, 10b, 10c, 10d Elastic material 11 Sleeve 12 Outer flat surface 13 Inner flat surface 14, 14a Inner tube 15, 15a Shaft 16 Mounting part 17 Step part 18 Locking part 19 Outer tube 20 Yoke 21 Tube part 22 Step part 23 Bending edge 24, 24a Protruding part 25 Recessed part 26 Elastic material 27 Through hole 28 Recessed groove 29 Synthetic resin 30 Stopper

Claims (1)

[Claims] 1. An inner member having an outer peripheral surface having a part as an outer flat surface, an outer member having an inner peripheral surface having a part as an inner flat surface, an outer peripheral surface of the outer member and the inner member. And an elastic member provided between the outer peripheral surface of the inner peripheral surface and the outer peripheral surface of the outer peripheral surface of the An elastic shaft coupling characterized in that a protrusion is formed in part of the flat surface so as to project toward another flat surface facing the flat surface.