JPH10325418A - Elastic coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operation stability. SOLUTION: In an elastic coupling, a damper 3 to damp vibration and provide an elastic play in a rotation direction is located between a cylinder shaft 1 and a shaft 2 inserted concentrically thereto. The damper 3 comprises an inner cylinder 5 securely fitted in externally of the region where, overlapped with the cylinder shaft 1, of the shaft 2 and having protrusion parts 5a radially in an out state in a plurality of spots in a peripheral direction on an outer peripheral surface; an outer cylinder 7 securely fitted internally of the region, overlapped with the shaft 2, of the shaft 1 and having recessed parts 7a formed in an inner peripheral surface and engaged with the respective protrusion parts 5a of the inner cylinder 5 with a gap in a rotation direction therebetween; and an elastic body 8 adhered to the inner surface of at least the recessed part 7a of the outer cylinder 7 in a state to make non-contact with the protrusion 5a of the inner cylinder 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastic shaft coupling for connecting two coaxial shafts in a state having elastic play in a rotational direction.

[0002]

2. Description of the Related Art As shown in FIG. 9, for example, this type of elastic shaft coupling is used in a steering mechanism of a motor vehicle, and cuts off the transmission of vibration from wheels to a steering wheel and utilizes the torsion of a damper. This gives the handle operation an elastic play. In the figure, 50 is a handle, 51 is a steering shaft, 52 is an input shaft of a steering gear device (power steering device), 53 and 54 are universal joints, and 55 is an elastic shaft joint.

A conventional example of the elastic shaft coupling 55 is disclosed in
There is one as shown in JP-A-8-50105. The contents of this publication will be described with reference to FIGS. FIG. 10 is a perspective view of the disassembled state, and FIG. 11 is a sectional view.

The elastic shaft coupling 55 includes a cylindrical shaft (tube shaft) 56 integrated with a yoke (not shown), a solid shaft 57 inserted into the cylindrical shaft 56, and an elastic body 5 interposed therebetween.
8

[0005] The cylindrical shaft 56 is provided with bulging portions 56a to 56c bulging radially outward at three circumferential positions. At the end of the shaft 57, three bulging portions 56a of the cylindrical shaft 56 are provided.
Are provided with three convex portions 57a to 57c which engage with each other through a gap in the rotation direction. Elastic body 58
Are vulcanized and bonded to the circumferential side surfaces of the first and second convex portions 57a and 57b and the region between the three convex portions 57a to 57c.

The elastic members 58 on both sides of the first convex portion 57a are brought into contact with the corresponding inner wall surfaces of the first bulging portion 56a, but the elastic members 58 on both sides of the second convex portion 57b. body 58 is therewith are allowed to face each other with a slight gap C _1, C ₁ with respect to the corresponding second protruding portion 56b. The third convex portion 57c and the corresponding third bulging portion 5
Large gaps C ₂ , C ₂ are provided between the gaps C ₂ and C ₂ .

With such a structure, as shown in FIG. 12, the characteristic of the torsion spring constant is that the elasticity between the first convex portion 57a and the bulging portion 56a is small in the small steering angle range from A to B. body 58 is elastically deformed becomes low spring constant, and reaches the B eliminates the gap C ₁ in FIG. 11, C from further B
In the steering angle range up to, the elastic body 58 between the second convex portion 57b and the bulging portion 56b is also elastically deformed to have a high spring constant. C
When it reaches the torque is transmitted directly gone clearance C ₂ in FIG. 11. That is, as the operation sensation, when rotation is started, an elastic reaction force gradually responds as the rotation angle increases, and finally there is a rigid response. Therefore, the handle operation is easy.

[0008]

By the way, in the above-mentioned conventional elastic shaft coupling 55, three convex portions 57a to 57c at the circumference are provided.
The transmission torque is changed in three steps depending on the thickness and presence or absence of the elastic body 58 between the bulges 56a to 56c and the protrusions 57a to 57c and the bulges 56a to 56c.
Since the torque transmitted between each of c is changed, it can be said that the inclination of the cylinder shaft 56 or the shaft 57 in the rotation direction is likely to occur, and the spring constant as designed may not be obtained. It is pointed out that the maneuverability is reduced.

In addition, since the cylindrical shaft 56 and the shaft 57 have complicated shapes, it takes time and effort to manufacture, so that the cost must be increased.

[0010] Accordingly, it is an object of the present invention to improve the steerability of an elastic shaft coupling.

[0011]

A first elastic shaft coupling according to the present invention has an elastic play in the rotational direction between a cylindrical shaft and a shaft concentrically inserted into the cylindrical shaft. An inner cylinder having a damper for causing the damper to be interposed, the damper being externally fitted and fixed to an area of the shaft overlapping the cylinder axis, and having a radially outwardly projecting portion at several circumferential points on the outer peripheral surface, In the region where the required opposing gap is formed with respect to the inner cylinder in a region where the shaft overlaps with the shaft in the cylindrical shaft, the inner cylinder is fixedly fitted in a state where the gap is formed on the inner peripheral surface of the inner cylinder through a gap in the rotational direction with respect to each protrusion of the inner cylinder. An outer cylinder provided with a concave portion to be engaged, and an elastic body adhered to at least an inner surface of the concave portion of the outer cylinder in a state of being in non-contact with a convex portion of the inner cylinder.

In a second elastic shaft coupling according to the present invention, a damper having a two-stage torsion spring constant is interposed between a cylindrical shaft and a shaft concentrically inserted therein. A first inner cylinder which is externally fitted and fixed to a region overlapping with the cylinder shaft in the shaft and has radially outwardly protruding portions provided on the outer peripheral surface at a plurality of circumferential positions of a required axial length region; It is fitted and fixed in a state where a required opposing gap is formed with respect to the first inner cylinder in the overlapping area, is formed to have a length substantially equal to the axial length of the first inner cylinder, and has an inner peripheral surface. An outer cylinder provided with a concave portion which engages with a convex portion of the first inner cylinder via a gap in a rotational direction in a required axial length region, and a shaft having no convex portion in the first inner cylinder; A second inner cylinder which is externally fitted and fixed in a required length direction in the direction; While being adhered to the inner peripheral surface inner cylinder facing the second outer circumferential surface and the outer cylinder of the first to the inner surface of at least the recess in the outer tube
And an elastic body adhered in a non-contact state with the projection of the inner cylinder.

[0013] In the above-mentioned elastic coupling, the elastic body adhered to the inner surface of the concave portion is provided with a projection on the inner surface circumferentially opposed to each convex portion of the inner cylinder in contact with each convex portion. preferable.

In short, according to the present invention, regarding the damper provided between the cylinder shaft and the shaft, the damper is provided between each convex portion provided at several circumferential positions of the inner cylinder and each concave portion provided at several circumferential positions of the outer cylinder. Since all the transmitted torques can be made the same, the rotational balance is improved, and the shaft and the cylindrical shaft are not twisted in the rotational direction. Also, since this damper is also a simple one made of an inner cylinder, an outer cylinder, and an elastic body,
It can be easily manufactured as compared with a conventional one in which a cylindrical shaft or a shaft itself is formed into a complicated shape.

By providing a projection on the elastic body adhered to the inner surface of the concave portion, it becomes easier to control the gap between the elastic body adhered to the inner surface of the concave portion and the convex portion so as to be kept constant.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the embodiments shown in FIGS.

1 to 5 relate to a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an elastic shaft coupling, and FIG. 2 is a sectional view taken along line (2)-(2) of FIG. 3 is (3)-in FIG.
(3) is an arrow view of a line section, FIG. 4 is an arrow view of a (4)-(4) line section of FIG. 1, and FIG. 5 is a view showing characteristics of a torsion spring constant.

In FIG. 1, reference numeral 1 denotes a cylindrical shaft having a yoke 1a to which a universal joint 20 is attached at an end thereof, and 2 denotes a solid extending from another universal joint and internally fitted to the cylindrical shaft 1 in the axial direction. Reference numeral 3 denotes a damper interposed between the cylindrical shaft 1 and the shaft 2.

2 which faces 180 degrees at the end of the cylindrical shaft 1
U-shaped notches 1b, 1b that are open toward one side in the axial direction are formed at the locations. At the position corresponding to the notches 1b, 1b of the cylindrical shaft 1 at the end of the shaft 2,
An annular stopper 4 is externally fitted and joined. At two places 180 degrees opposite to each other on the outer peripheral surface of the stopper 4,
Protruding pieces 4a, 4a are formed radially outward, and the protruding pieces 4a, 4a are engaged with the notches 1b, 1b of the cylindrical shaft 1 individually in a state having a required gap in the circumferential direction. Have been combined.

The damper 3 has a structure in which the torsion spring constant has a two-step characteristic, and includes a first inner cylinder 5 and a second inner cylinder 6.
And an outer cylinder 7 and an elastic body 8 such as rubber.
The first inner cylinder 5, the second inner cylinder 6, and the outer cylinder 7 are made of metal.

The first inner cylinder 5 is externally fitted and fixed to the shaft 2 by press-fitting. Protrusions 5a projecting radially outward are provided.

The second inner cylinder 6 is press-fitted and externally fitted to a region on the outer peripheral surface of the first inner cylinder 5 where the convex portion 5a does not exist, and is made of a thin cylindrical member.

The outer cylinder 7 is fitted and fixed to the cylinder shaft 1 by press-fitting, and has a length substantially equal to the axial length of the first inner cylinder 5. In a region corresponding to each convex portion 5a of the first inner cylinder 5 in a region substantially half of the outer cylinder 7 in the axial direction, the concave portions 7a.・ ・ Is provided.

The elastic body 8 is vulcanized and bonded to the entire inner peripheral surface of the outer cylinder 7 and vulcanized to the outer peripheral surface of the second inner cylinder 6. Further, the elastic body 8 adhered to the substantially half area in the axial direction where the concave portion 7a of the outer cylinder 7 exists does not contact the substantially half area in the axial direction where the convex part 5a exists in the first inner cylinder 5. ing. That is, the elastic body 8 bonded to the inner surfaces of the four concave portions 7a of the outer cylinder 7 and the first inner cylinder 5
A required gap is provided between each of the four convex portions 5a,..., And the gap serves as play in the rotation direction.

The elastic shaft coupling configured as described above has a structure in which the transmission torque is changed in three stages by the damper 3 and the stopper 4, as shown in FIG. The horizontal axis shows the relative rotation angle (deg) between the cylinder shaft and the shaft, and the vertical axis shows the transmission torque (N · m).

In the range a of -1 ° to 1 °, the outer cylinder 7 of the damper 3 slightly rotates by the same angle due to the minute rotation of the cylinder shaft 1 caused by the resonance between the tire and the suspension.
The elastic body 8 between the inner cylinder 5 and the second inner cylinder 6 is twisted. In this region a, the elastic body 8 adhered to the inner surfaces of the four concave portions 7a of the outer cylinder 7 has the convex portions 5a of the first inner cylinder 5.
5 or the contact is slight, so that the gradient is small and the torsion spring constant is low in the characteristic curve of FIG. 5. For example, the resonance between the tire and the suspension is absorbed by the elastic body 8. To prevent transmission to the steering wheel. That is, the function of absorbing flutter is sufficiently exhibited.

Regions b ₁ and 1 ° between −2.5 ° and −1 °
In to 2.5 ° in the region b _2, rotational force is added to the shaft 2 together transmitted to the elastic member 8 between the first inner cylinder 5 and the second inner cylinder 6, the first inner cylinder 5 The protrusions 5a are 4 of the outer cylinder 7.
The rotating force is transmitted from the first inner cylinder 5 to the outer cylinder 7 by contacting the elastic body 8 adhered to the inner surfaces of the two recesses 7a.
As a result, the entire elastic body 8 is compressed and deformed, so that the gradient in the characteristic curve of FIG. 5 is large and the torsion spring constant becomes a high spring constant. Have achieved.

In the region c ₁ exceeding −2.5 ° and the region c ₂ exceeding 2.5 °, the projecting piece 4 of the stopper 4 is used.
a, 4a abut on the notches 1b, 1b of the cylinder shaft 1 to directly transmit the rotational force from the shaft 2 to the cylinder shaft 1.

The angles ± 1 ° and ± 2.5 ° at the point where the torsion spring constant changes are merely given as examples, and these angles may vary depending on the type of vehicle to which the elastic coupling is used and other conditions. Varies by.

According to the first embodiment, with respect to the damper 3 provided between the cylinder shaft 1 and the shaft 2, each of the protrusions 5 a provided at several locations on the circumference of the first inner cylinder 5 and the outer cylinder 7 Since the torque transmitted to each of the recesses 7a provided at several places around the circumference is all the same, the rotation balance can be improved, and the inclination of the cylinder shaft 1 or the shaft 2 in the rotation direction can be prevented.
As a result, the maneuverability can be improved. Also, the damper 3 has a simple structure formed by the first inner cylinder 5, the second inner cylinder 6, the outer cylinder 7, and the elastic body 8,
As compared with the conventional case in which the cylindrical shaft 1 and the shaft 2 themselves are formed in a complicated shape, the manufacture is simplified, and it is possible to contribute to cost reduction.

In the first embodiment, the elastic member 8 interposed in the power transmission path from the first inner cylinder 5 to the outer cylinder 7 is used.
Is adhered to the inner surface of the concave portion 7a of the outer cylinder 7 so as to be sandwiched between the convex portion 5a and the inner surface of the concave portion 7a during power transmission.
This elastic body 8 is hardly peeled off. Incidentally, the inner peripheral surface of the outer cylinder 7 is made cylindrical, and the concave portions 7
In the case where the elastic body 8 is configured to be adhered in pieces so as to form the elastic body 8a, the elastic body 8 is considered to be easily peeled off from the outer cylinder 7 by the rotational power repeatedly received from the convex portion 5a. There is no such problem of peeling.

6 to 8 relate to a second embodiment of the present invention. FIG. 6 is an enlarged sectional view of a main part of the elastic joint, FIG. 7 is an exploded view of a main part of the elastic joint, and FIG. It is a figure showing the characteristic of the torsion spring constant of a shaft coupling.

The second embodiment differs from the first embodiment in that the elastic body 8 bonded to the inner surface of the concave portion 7a of the outer cylinder 7 has a gap between the elastic body 8 and the convex portion 5a of the first inner cylinder 5. Is provided with a projection 8a for keeping the constant.

That is, the gap between the elastic body 8 adhered to the inner surface of the concave portion 7a and the convex portion 5a is the first
Is set when the inner cylinder 5 is assembled. In the case of the first embodiment, it is considered that it takes time and effort to set the gaps on both sides in the circumferential direction of the protrusion 5a. However, if the projection 8a is provided as in the second embodiment,
Even if the assembling work is performed casually, it is possible to contribute to the improvement of workability, for example, the two gaps can be made substantially equal. It is necessary to set the two gaps to be equal in order to equalize the torsion angles in both the forward and reverse rotation directions.

The location where the projection 8a is formed is preferably determined in consideration of the following points. First, it is located at a substantially central position in the radial direction. On the other hand, in the axial direction, as shown in FIG.
Immediately before the portion where no is present fits into the second inner cylinder 6, the elastic body 8 adhered to the inner surface of the concave portion 7 a of the outer cylinder 7 and the convex portion 5 a of the first inner cylinder 5 are in the axial direction. And within the overlapping area. With this determination, the first inner cylinder 5 is almost free when the adjustment is performed to make the two gaps substantially equal in the assembling process.
This adjustment work can be easily performed.

In addition, by providing the projection 8a,
As shown in FIG. 8, the boundaries d ₁ and d ₂ transitioning from the region a having a low spring constant to the regions b ₁ and b ₂ having a high spring constant become smooth, and the operation feeling can be made gentle. The reason is that, in the elastic body 8, in the initial elastic deformation, the projections 8a take charge, and thus the drag becomes sufficiently small, and as the elastic deformation progresses, the elastic body 8 itself takes charge, so that the drag gradually increases. is there.

The present invention is not limited to the first and second embodiments, and various applications and modifications are conceivable.

(1) In the first and second embodiments, the U-shaped cutout portions 1b, 1b of the cylindrical shaft 1 are optional, for example, they can be elongated holes.

(2) In the first and second embodiments, the number of the convex portions 5a of the first inner cylinder 5 is arbitrary, but the arrangement thereof is equally distributed around the circumference in consideration of the rotational balance. It is preferable to set.

(3) In the first and second embodiments, the elastic body 8 adhered to the inner surfaces of the four concave portions 7a of the outer cylinder 7.
, And the four opposing gaps of the four protrusions 5a of the first inner cylinder 5 can be 180 degrees opposite to each other, and the gap size of each pair can be made to differ greatly.
In this case, the angle of the refraction point of the torsion spring constant can be changed.

[0041]

According to the first aspect of the present invention, regarding the damper provided between the cylindrical shaft and the shaft, each of the projections provided at several locations on the circumference of the inner cylinder and the respective dampers provided at several locations on the circumference of the outer cylinder. Since all the torques transmitted to the recesses can be made the same, the rotational balance can be improved, and the inclination of the cylinder shaft or the shaft in the rotational direction can be prevented, and as a result, the operability can be improved. In addition, this damper has a simple structure consisting of an inner cylinder, an outer cylinder, and an elastic body, making it easier to manufacture than a conventional cylinder shaft or shaft that has a complicated shape. , And contribute to cost reduction.

According to the elastic shaft coupling of the second aspect, the same effect as that of the first aspect can be obtained in a configuration in which the damper has a two-stage torsion spring constant.

Further, if the elastic member adhered to the inner surface of the concave portion is provided with a projection, the gap between the elastic member adhered to the inner surface of the concave portion and the convex portion can be kept constant. Because it is easier to manage, it is possible to contribute to improvement of reliability such as improvement of assembly accuracy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an elastic shaft coupling according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line (2)-(2) of FIG.

FIG. 3 is a sectional view taken along line (3)-(3) of FIG.

FIG. 4 is a sectional view taken along line (4)-(4) of FIG.

FIG. 5 is a view showing characteristics of a torsion spring constant of the elastic shaft coupling according to the first embodiment.

FIG. 6 is an enlarged sectional view of a main part of an elastic shaft coupling according to a second embodiment of the present invention.

FIG. 7 is an exploded view of a main part of the elastic shaft coupling according to the second embodiment.

FIG. 8 is a diagram showing characteristics of a torsion spring constant of the elastic shaft coupling according to the second embodiment.

FIG. 9 is a side view showing a steering mechanism of the vehicle.

FIG. 10 is an exploded perspective view of a conventional elastic shaft coupling.

FIG. 11 is a sectional view of the elastic shaft coupling of FIG. 10;

12 is a view showing characteristics of a torsion spring constant of the elastic shaft coupling of FIG. 10;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical shaft 2 Shaft 3 Damper 5 1st inner cylinder 5a Convex part of 1st inner cylinder 6 2nd inner cylinder 7 Outer cylinder 7a Concave part of outer cylinder 8 Elastic body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Fujii 4630 Yagarashi-no-machi, Renjima-jima, Kurashiki-shi, Okayama Inside Kurashiki Chemical Co., Ltd. Machine Industry Co., Ltd.

Claims (3)

[Claims] 1. An elastic shaft coupling in which a damper for damping vibration and having elastic play in a rotating direction is interposed between a cylindrical shaft and a shaft concentrically inserted therein. An inner cylinder that is externally fitted and fixed in a region of the shaft overlapping the cylinder shaft and has radially outwardly projecting portions at several locations on the outer peripheral surface; and an inner cylinder in a region of the cylinder shaft overlapping the shaft. An outer cylinder which is internally fitted and fixed in a state where a required opposing gap is formed, and has a concave portion provided on the inner peripheral surface to engage with each convex portion of the inner cylinder via a gap in the rotation direction; An elastic body bonded to at least an inner surface of the concave portion of the outer cylinder in a non-contact state with the convex portion of the inner cylinder. 2. An elastic shaft coupling in which a damper having a two-stage torsion spring constant is interposed between a cylindrical shaft and a shaft concentrically inserted therein, wherein the damper comprises a shaft and a cylindrical shaft. A first inner cylinder which is externally fitted and fixed to the overlapping area and has radially outwardly protruding portions provided on the outer peripheral surface at several circumferential positions of the required axial length area; The first inner cylinder is fitted and fixed in such a manner that a required opposing gap is formed, is formed to have substantially the same axial length as the first inner cylinder, and has a required axial length on the inner peripheral surface. An outer cylinder provided with a concave portion which is engaged with each convex portion of the first inner cylinder via a gap in a rotational direction in a region, and a required axial length region where no convex portion exists in the first inner cylinder. A second inner cylinder externally fitted to and fixed to an outer peripheral surface of the second inner cylinder, Second in fine said barrel
While being bonded to the inner peripheral surface facing the inner cylinder of
An elastic body bonded to at least an inner surface of the concave portion of the outer cylinder in a non-contact state with the convex portion of the first inner cylinder. 3. An elastic body adhered to the inner surface of the concave portion, wherein an inner surface circumferentially opposed to each convex portion of the inner cylinder is provided with a projection that comes into contact with each convex portion. 3. The elastic shaft coupling according to 1 or 2.