JPH11210798A - Rotary damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary damper capable of producing the desired damping force which is always stable, without impairing cost performance and the need for compactness. SOLUTION: In a rotary damper RD having a plurality of rotating-shaft-side and housing-side plates 2, 7 supported, respectively, against the outer periphery of a rotating shaft 1 and the inner periphery of a housing 4 within a fluid chamber A in such a way as to be capable of transmitting rotation, with their respective side faces opposed to each other with a predetermined gap, the rotating-shaft-side and housing-side plates 2, 7 have, respectively, an outer edge and an inner edge on the same side at their respective free ends along the direction of an axis while the plates 2, 7 are held assembled to the rotating shaft 1 and the housing 4, respectively, the outer and inner edges constituting a plate-interval-maintaining projecting part which abuts on the supported side face of each of the opposite plates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary damper that attenuates rotation, and more particularly to a member that rotates by a relative displacement between a sprung and unsprung state, such as a rotating shaft of a lower arm or an upper arm in a vehicle. The present invention relates to a rotary damper that is suitable for being mounted and used as a suspension damper.

[0002]

2. Description of the Related Art As a conventional rotary damper, for example, a rotary damper described in Japanese Patent Application Laid-Open No. Sho 64-12151 is known. The conventional rotary damper includes a housing having a fluid chamber filled with a viscous fluid, a rotation shaft provided in the fluid chamber of the housing so as to be rotatable relative to the housing, and an outer periphery of the rotation shaft in the fluid chamber. And a plurality of rotating shaft-side and housing-side plates that are supported by the housing and the inner periphery of the housing, respectively, and the sides of the rotating shaft and the housing have a predetermined gap and face each other in the axial direction of the rotating shaft. . That is, in the conventional rotary damper, when the rotating shaft side plate and the housing side plate rotate relative to each other, the viscous fluid filled between them is forcibly moved at a flow rate corresponding to the relative rotation speed. A viscous friction force corresponding to the viscosity of the viscous fluid is generated, and the viscous resistance becomes a damping force.

[0003]

However, the conventional rotary damper has a problem as described below.

That is, in general, the damping force (generated torque) T of a rotary damper having n pairs of opposing plates is expressed by the following equation. ^{T = {π × 10 -6 ×} (d 1 4 -d 2 4) × ν × ω × n} /
(2 × 9800 × δ) where d ₁ is the effective outer shape of the shear surface, d ₂ is the effective inner diameter of the shear surface, ν is the kinematic viscosity of the viscous fluid, ω is the relative angular velocity between the plates, and δ is the gap between the plates. As is clear from the above equation, the smaller the value of the gap between the opposing plates, the larger the generated damping force. Therefore, in order to generate a large damping force as a damper, the gap between the plates should be set to a small value. Although it is necessary to set, if the gap between the plates is reduced, the generated damping force value is greatly affected by the flatness of the plate, and the generated damping force becomes unstable due to the variation in the gap, so that the desired stable In order to obtain a damping force, it is necessary to accurately control the flatness of each plate.

However, since it is necessary to reduce the thickness of each plate as much as possible due to the demand for compactness, it is extremely difficult to accurately process and manage the flatness of each plate. By increasing the thickness of each plate,
Although it is possible to increase the flatness of each plate and eliminate variations in the gap, according to this method, the axial size of the damper is increased by the increased thickness of the plate, thus increasing the size of the mechanism. At the same time, the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a rotary damper capable of always generating a stable and desired damping force without sacrificing cost and compactness requirements. It is intended to provide.

[0007]

According to a first aspect of the present invention, there is provided a rotary damper having a housing having a fluid chamber filled with a viscous fluid therein, and a housing in the fluid chamber of the housing. A rotating shaft provided to be relatively rotatable, and supported in the fluid chamber so as to be able to transmit rotation to an outer periphery of the rotating shaft and an inner periphery of the housing, and both sides face each other with a predetermined gap. In the rotary damper having a plurality of rotating shaft side and a housing side plate, each of the rotating shaft side and the housing side plate is on the same side in the axial direction on its free end side in the assembled state to the rotating shaft and the housing, A means for forming a projection for holding a plate interval, which is in contact with a side surface of each of the opposing plates on each support side, is formed. A rotary damper according to a second aspect of the present invention is the rotary damper according to the first aspect, wherein a surface treatment for enhancing abrasion resistance and lubricity is performed on a contact portion of the plate gap holding projection with the opposing plate. Means. A rotary damper according to a third aspect is the rotary damper according to the first or second aspect, wherein the rotating shaft side plate and the housing side plate are formed in a disk spring shape.

[0008]

In the rotary damper according to the first aspect of the present invention,
As described above, the plate gap holding projection formed on the free end side of each plate abuts against the side surface on each support side of the opposing plate, thereby forming a stable desired gap between the plates. Therefore, a stable and desired damping force can always be generated.

In the rotary damper according to the second aspect of the present invention, a portion of each plate that comes into contact with the opposing surface is subjected to a surface treatment that enhances abrasion resistance and lubricity. In this case, the generation of metal powder and the like (contaminants) due to friction between the plates is suppressed, thereby improving the durability.

In the rotary damper according to the third aspect, since both plates are formed in the shape of a disc spring, the plates can be easily formed, the cost can be reduced, and the contact portion can be suppressed to a minimum area. Therefore, the generation of metal powder and the like (contaminants) due to friction between the plates when the plates rotate relative to each other while abutting on the opposing plates is suppressed, thereby improving the durability.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view (S1-S1 of FIGS. 2 and 3) showing a rotary damper RD according to an embodiment of the present invention.
As shown in the figure, the rotary damper RD according to the embodiment of the present invention includes a rotary shaft 1 fixed to the vehicle body side and a housing connected to the rotary shaft bearing side on the lower arm side. 2 is provided.

The rotary shaft 1 is formed in a cylindrical shape, and the center of the outer peripheral surface thereof has a large diameter portion 11 having a diameter larger than the left and right ends.
The spline shaft 12 is formed on the outer peripheral surface of the large diameter portion 11.
As shown in (S2-S2 cross-sectional view in FIG. 1), the rotating shaft side plate 2 having a spline hole 21 at the center and the annular spacer 3 are alternately mounted.

FIG. 3 is a sectional view of the rotary shaft side plate 2. As shown in the figure, the rotating shaft side plate 2 is inclined to one side in the axial direction of the spline hole 21 from the spline hole 21 in the circumferential direction, and is formed in a substantially disc spring shape. In addition, an outer peripheral edge portion (a protruding portion for maintaining a plate interval) 2a protruding leftward in the drawing from an inner peripheral edge portion of the rotating shaft side plate 2 is subjected to a surface treatment for enhancing abrasion resistance and lubricity.

The rotating shaft side plate 2 is mounted on the rotating shaft 1 in a state where the outer peripheral edge 2a subjected to the surface treatment faces in the same direction.

The housing 4 is formed in a substantially cylindrical shape by a right side wall portion 41, a left side wall portion 42 and an outer peripheral cylindrical portion 43, and is provided around the right and left ends of the rotary shaft 1 which are not formed on the spline shaft 11. The inner peripheral holes of the right side wall 41 and the left side wall 42 are mounted via bearings 41a and 42a, respectively.
The seal members 41b, 42
b is provided. Also, the right side wall 41 and the left side wall 4
2 is formed smaller in diameter than the large diameter portion 11 of the rotating shaft 1.

Therefore, the housing 2 is provided so as to be rotatable in the axial direction relative to the rotary shaft 1 and is prevented from moving in the axial direction.

The inner peripheral surface of the outer cylindrical portion 43 is shown in FIGS. 2 (S2-S2 sectional view in FIG. 1) and FIG. 4 (S3-S3 in FIG. 1).
As shown in the cross-sectional view), a spline hole 43a is formed, and an annular spacer 6 is provided on an inner peripheral surface of the spline hole 43a, and a housing having a spline shaft-like outer peripheral shape engageable with the spline hole 43a. The side plates 7 are alternately mounted.

FIG. 5 is a sectional view of the housing-side plate 7. As shown in FIG.
Is inclined toward one side in the axial direction of the inner circumferential circle from the outer circumference to the inner circumferential direction, and is formed in a substantially disc spring shape. In addition, a surface treatment for enhancing abrasion resistance and lubricity is applied to an inner peripheral edge portion (a protruding portion for maintaining a plate interval) 7a of the housing-side plate 7 projecting leftward from the outer peripheral edge portion in the drawing. The housing-side plate 7
Is mounted on the rotating shaft 1 in a state where the inner peripheral edge 7a subjected to the surface treatment faces in the same direction.

An outer peripheral cylindrical portion 43 is fixed to the outer periphery of the right side wall portion 41 and the left side wall portion 42 by caulking, and is provided between the outer peripheral surfaces of the right side wall portion 41 and the left side wall portion 42 and the outer peripheral cylindrical portion 43. Are provided with seal rings 41c and 42c.
A sealed hollow chamber (fluid chamber) A is formed between the rotary shaft 1 and the housing 4. And this hollow chamber A
Is filled with a viscous fluid 5 in a sealed state, and the rotating shaft side plates 2 and the housing side plates 7 are alternately arranged in the hollow chamber A. Collars 8a and 8b are interposed between the right side wall portion 41 at the right end of the hollow chamber A and the annular spacer 8 and the rotating shaft side plate 2 at the right end.

A set spring 9 is provided on the left end of the hollow chamber A between the left side wall 42 and the left end housing side plate 7 and the annular spacer 3 via set plates 9a and 9b. Each plate and spacer assembled in A are pressed and urged rightward.
Therefore, the rotating shaft side plate 2 and the housing side plate 7 which are alternately arranged are assembled such that the outer peripheral edge 2a and the inner peripheral edge 7a are in contact with the respective supporting side surfaces of the opposing plates at a predetermined pressure. Have been. Therefore, the axial length t2 of both plates 2 and 7 when assembled in the housing 4 is shorter than the length t1 before assembly shown in FIGS.

Next, the operation of the embodiment of the present invention will be described. When the rotating shaft 1 and the housing 4 rotate relative to each other, the rotating shaft-side plate 2 supported by the rotating shaft 1 and the housing-side plate 7 supported by the housing 4 rotate relative to each other, and the space between the two plate-facing surfaces is filled. Viscous friction is generated when the viscous fluid 5 forcibly moves at a flow rate corresponding to the relative angular velocity, and a predetermined damping force is generated by viscous resistance due to the viscous friction force.

At this time, the outer peripheral edges 2a of the plates 2 and 7
And the inner peripheral edge 7a relatively rotates in a state of contact with the opposing surfaces, so that frictional resistance is generated.
In addition, since the inner peripheral edge portion 7a is subjected to a surface treatment that enhances wear resistance and lubricity, the generated frictional resistance is small, and the wear of the plate due to friction is suppressed.

As described above, according to the rotary damper RD of the embodiment of the present invention, each plate 2, 7
Even if the thickness is reduced, the gap between the plates 2 and 7 does not vary in the assembled state, so that the desired damping is always stable without sacrificing cost and compactness requirements. The force can be generated.

Further, since the rotating shaft side plate 2 and the housing side plate 7 are formed in the shape of a disc spring, the forming process is simple, and the contact portion with the opposing plate is suppressed to a minimum area. Therefore, the frictional resistance can be slightly suppressed, and the durability can be improved.

Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to the embodiments, and design changes and the like may be made without departing from the spirit of the present invention. Even if present, it is included in the present invention. For example, in the embodiment of the invention, the case where the lower arm of the vehicle is provided on the rotating shaft bearing or the like is taken as an example. However, the present invention is applied to a case where the relative movement between arbitrary members is attenuated in the rotation direction. be able to.

In the embodiment of the present invention, each plate is formed in the shape of a disc spring, so that the outer peripheral edge or the inner peripheral edge is formed as a projection for maintaining the plate interval. By forming a protruding edge portion protruding in one side direction on the circumference, a protruding portion for maintaining a plate interval may be used.

[0027]

As described above, according to the rotary damper of the present invention, a housing having a fluid chamber filled with a viscous fluid therein, and a rotatable relative to the housing in the fluid chamber of the housing are provided. A plurality of rotating shafts which are supported so as to be able to transmit rotation to the outer periphery of the rotating shaft and the inner periphery of the housing in the fluid chamber, and whose sides face each other with a predetermined gap. And a housing-side plate, wherein each of the rotating shaft-side and housing-side plates has an axially identical side surface at its free end when assembled to the rotating shaft and the housing. With the configuration in which the protruding portion for maintaining the plate interval that contacts the side surface on the side is formed, cost and Without sacrificing the request of transfected reduction effect is obtained that it is possible to always generate a stable desired damping force. A rotary damper according to a second aspect of the present invention is the rotary damper according to the first aspect, wherein a surface treatment for enhancing abrasion resistance and lubricity is performed on a contact portion of the plate gap holding projection with the opposing plate. With this configuration, the generation of metal powder and the like (contaminants) due to friction between the plates when the plates rotate relative to each other while abutting against the opposing plates is suppressed, thereby improving durability. Is obtained. According to a third aspect of the present invention, in the rotary damper according to the first or second aspect, the rotary shaft-side plate and the housing-side plate are formed in a disc spring shape.
Plates are easy to form, cost is reduced, and the contact area can be kept to a minimum area. Therefore, when the plate rotates relative to the opposite plate while abutting, metal powder etc. due to friction between the plates The generation of (contaminants) is suppressed, and thereby the effect of improving durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotary damper RD according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line S2-S2 of FIG.

FIG. 3 is a cross-sectional view of a rotating shaft side plate according to the embodiment of the present invention.

FIG. 4 is a sectional view taken along line S3-S3 of FIG.

FIG. 5 is a sectional view of a housing-side plate according to the embodiment of the present invention.

[Explanation of symbols]

 RD Rotary damper A Fluid chamber 1 Rotating shaft 11 Large diameter portion 12 Spline shaft 2 Rotating shaft side plate 2a Outer peripheral edge (protruding portion for maintaining plate interval) 21 Spline hole 3 Annular spacer 4 Housing 41 Right side wall portion 41a Bearing 41b Seal member 41c Seal ring 42 Left side wall portion 42a Bearing 42b Seal member 42c Seal ring 43 Outer cylindrical portion 43a Spline hole 5 Viscous fluid 6 Annular spacer 7 Housing side plate 7a Inner peripheral edge (protruding portion for maintaining plate interval) 8a Color 8b Color 9 set Spring 9a Set plate 9b Set plate

Claims (3)

[Claims] 1. A housing having a fluid chamber filled with a viscous fluid therein, a rotating shaft provided in the fluid chamber of the housing so as to be rotatable relative to the housing, an outer periphery of the rotating shaft in the fluid chamber and the housing. And a plurality of rotating shaft sides and a housing side plate, each of which is supported so as to be able to transmit rotation to the inner circumference of the rotating shaft, and the side surfaces of which are opposed to each other with a predetermined gap. The side plate and the housing side plate are formed with a plate interval holding projection which is in contact with the side surface on the support side of the opposed plate on the same side surface in the axial direction on each free end side in the assembled state to the rotating shaft and the housing. A rotary damper characterized in that: 2. The rotary damper according to claim 1, wherein a surface treatment for enhancing abrasion resistance and lubricity is applied to a contact portion of the plate spacing maintaining projection with the opposing plate. 3. The rotary damper according to claim 1, wherein said rotary shaft side plate and said housing side plate are formed in a disk spring shape.