JPH08166033A - Rotary damper - Google Patents

Abstract

PURPOSE: To provide a rotary damper which can change generating damping force characteristics by relative rotational positions. CONSTITUTION: A rotary damper is equipped with a housing 2 having a hollow chamber A whose inside is filled with viscous fluid 12, a rotary shaft 1 which is relatively rotatively arranged against the housing 2 in the hollow chamber A of the housing 2, and a plural couple of annular plates 4, 16 which are respectively arranged along the outer circumference of the rotary shaft 1 and the inner circumference of the housing 2 in the hollow chamber A, and whose side surfaces are opposed to each other at predetermined intervals Y. Recessed parts 41, 161 which are orthogonalized to the opposite surfaces in the circumferential directions of rotary surfaces against the rotary surfaces centering around the rotary shaft 1, are formed on the opposite surfaces of both annular plates 4, 16, so that the mutual intervals Y between the opposite surfaces of both annular plates 4, 16, are changed by the relative rotational positions of both annular plates 4, 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary damper for damping rotation of an arm by being provided in a rotary bearing portion of a lower arm or an upper arm of a vehicle, for example.

[0002]

2. Description of the Related Art Conventionally, as a rotary damper, for example, one disclosed in Japanese Patent Laid-Open No. 4-321827 is known.

This conventional rotary damper has a plurality of arm-side fins disposed at appropriate intervals in a housing formed at the other end of a lower arm having wheels at one end, and a vehicle body side. A plurality of shaft-side fins that are held between the arm-side fins and that are connected to a rotary shaft that penetrates through openings formed in the central portions of the plurality of arm-side fins. A reverse rotation mechanism for rotating the rotary shaft in the opposite direction to the rotation direction of the housing is disposed between the housing and the bearing, and
The gap formed between the arm-side fin and the shaft-side fin is filled with viscous fluid.

That is, in this conventional rotary damper,
The reversing mechanism causes the shaft-side fins to rotate in the direction opposite to the rotation direction of the arm-side fins, and as a result, the viscous fluid interposed between the fins is a so-called double the rotational momentum of the arm-side fins. Viscosity based on the relative momentum (relative velocity) is exhibited, and therefore, an effective damping action can be exhibited as compared with the rotation amount of the arm-side fins.

[0005]

However, the above-mentioned conventional rotary damper has the following problems.

That is, in the rotary damper, when the both fins rotate relative to each other, the viscous fluid filled in the gap between the two fins is forcibly moved at a flow velocity corresponding to the relative rotation speed, and at that time, depending on the viscosity of the viscous fluid. Viscous frictional force is generated, and the viscous resistance due to this viscous frictional force becomes the damping force,
Therefore, the damping force changes in inverse proportion to the gap between both fins, as shown in the following equation (1).

Damping force = viscosity of viscous fluid × relative rotational angular velocity × opposing area / gap spacing (1) However, in the conventional rotary damper, the gap spacing between both fins is the relative rotation of both fins. Since the structure is such that it is always constant regardless of the angle, and a constant damping force is always generated when the relative rotation angle from the relative rotation neutral position is small or large. If is set to a small value, the damping force becomes excessive when the relative rotation angle is small (small stroke), which deteriorates the riding comfort of the vehicle, and conversely, the clearance gap is set to secure the riding comfort of the vehicle. If it is set to a large value, the damping force becomes insufficient when the relative rotation angle is large (large stroke), and it becomes impossible to secure the vibration damping property of the vehicle.

The present invention has been made in view of the above-mentioned conventional problems, and it is a first object of the present invention to provide a rotary damper capable of changing the generated damping force characteristic depending on the relative rotational position. A second object of the present invention is to provide a rotary damper capable of ensuring both the riding comfort of the vehicle and the damping property of the vehicle.

[0009]

In order to achieve the above object, a rotary damper according to a first aspect of the present invention has a housing having a fluid chamber filled with a viscous fluid therein, and a housing inside the fluid chamber of the housing. And a pair of plates provided on the outer circumference of the rotary shaft and the inner circumference of the housing in the fluid chamber so as to be rotatable relative to each other, and the side surfaces of the two plates face each other with a predetermined gap. And a relative rotation of both plates by forming a concave-convex portion in a direction orthogonal to the facing surface in the circumferential direction with respect to the rotating surface centering on the rotation axis on the facing surface of the both plates. The means is configured so that the gap between the facing surfaces of both plates changes depending on the position.

Further, in the rotary damper of the second aspect, when the relative rotation angle from the relative rotation neutral position between the housing and the rotation shaft is small, the gap between the facing surfaces of both plates becomes large, and the relative rotation angle becomes large. When the size is large, the means is such that the concavities and convexities on the opposing surfaces of both plates are formed so that the gap between the opposing surfaces of both plates becomes small.

[0011]

In the rotary damper according to claim 1 of the present invention,
With the configuration described above, when the rotating shaft and the housing rotate relative to each other, the plates adjacent to each other rotate relative to each other, and the viscous fluid filled in the gap between the plate facing surfaces responds to the relative rotational angular velocity. A viscous frictional force is generated when forcedly moving at a high flow velocity, and a predetermined damping force is generated by viscous resistance due to this viscous frictional force.

Further, since the concavo-convex portion in the direction orthogonal to the opposing surface is formed in the circumferential direction with respect to the rotational surface centering on the rotational axis, the opposing surfaces of the both plates are opposed to each other. The gap between the facing surfaces of both plates changes depending on the rotational position. Therefore, the generated damping force can be changed depending on the relative rotational position of both plates.

Further, in the rotary damper according to the second aspect of the present invention, the unevenness of the opposing surfaces of the plates is such that when the relative rotation angle from the relative rotational neutral position between the housing and the rotating shaft is small, the gap between the opposing surfaces of the plates is small. When the relative rotation angle is large, the gap between the facing surfaces of both plates is small and the generated damping force is large.

Therefore, when this rotary damper is used as a damping means in a vehicle, the vibration transmission to the spring is suppressed by a small damping force during a small stroke to secure the riding comfort of the vehicle, and at the time of a large stroke. With the large damping force, the vehicle vibration can be suppressed and the steering stability of the vehicle can be secured.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. (First Embodiment) FIG. 1 is a sectional view showing a rotary damper according to a first embodiment of the present invention (a sectional view taken along line D-D in FIGS. 2 and 3), and FIGS. 2 and 3 are B in FIG. -B line and C
FIG. 6 is a cross-sectional view taken along line C, and as shown in these drawings, the rotary damper of this embodiment includes a rotary shaft 1 fixed to the vehicle body side and a housing 2 connected to a bearing side on the lower arm side. ing.

The rotary shaft 1 is formed in a cylindrical shape, and a flange 1a is integrally formed on the outer periphery of the right end portion thereof. The rotary shaft 1 is formed on the spline shaft 1b with a small amount of the right end left on the outer peripheral surface thereof, and the annular plate 4 having the spline holes 4a and the annular spacer 5 are alternately attached to the spline shaft 1b. At the same time, a cylindrical stud (rotating shaft) 6 having a spline hole 6a at the left end of the spline shaft 1b in the rotary shaft 1 and a flange 6b at the outer periphery of the left end is spline-engaged. A plurality of annular plates 4 are assembled in a state where they are axially fixed at a predetermined interval and are fixed to the rotary shaft 1 in the rotational direction and the axial direction. The stud 6 is fixed to the rotary shaft 1 by welding the end surface and the gap of the spline engaging portion is sealed.

The housing 2 has a stud 6 and a right end outer periphery of the rotary shaft 1 which is not formed on the spline shaft 1b.
Center holes 2c and 2d of the left and right side walls 2a and 2b on the outer periphery of
And the left and right end surface side walls 2a, 2b
The ball bearings 7 and 8 are interposed between the outer surface of the rotary shaft 1 and the inner surfaces of the left and right flanges 1a and 6b, respectively, so that they can rotate relative to the rotary shaft 1 and are prevented from moving in the axial direction. . Further, the rotary shaft 1 and the sub-housing 3 are sealed by sealing the space between the rotary shaft 1 and the inner peripheral surfaces of the center holes 2c, 2d in the left and right side wall surfaces 2a, 2b of the housing 2 respectively.
A closed hollow chamber (fluid chamber) A is formed between and. The hollow chamber A is filled with the viscous fluid 12 in a sealed state.

The housing 2 has side walls 2 on both left and right side surfaces.
Bearings 13 and 14 provided on the inner peripheral surfaces of the center holes 2c and 2d of a and 2b are provided so as to be rotatable relative to the rotary shaft 1.

Left side wall 2 of the housing 2
The a is formed separately from other parts, and is integrated by welding when assembled. That is, the inner peripheral surface of the housing 2 is formed in the spline hole 2e, and an annular spacer 15 and an annular plate 16 having a spline shaft-shaped outer peripheral shape engageable with the spline hole 2e are alternately formed in the spline hole 2e. Then, the left end side wall 2a is attached and welded, so that the plurality of annular plates 16 are assembled in a state in which they are held in the axial direction at predetermined intervals and are fixed to the housing 2 in the rotation direction. There is. The annular plates 4 on the side of the rotary shaft 1 and the annular plate 16 on the side of the housing 2 are assembled alternately, so that both annular plates 4 and 16 are viscous fluid 12.
Are alternately arranged in the hollow chamber A filled with the above, and the side surfaces thereof face each other with a predetermined gap Y in the axial direction. Therefore, each gap Y is filled with the viscous fluid.

Of the facing surfaces of the annular plate 4 on the rotating shaft 1 side and the annular plate 16 on the housing 2 side, the rotating shaft 1
As shown in FIG. 2, the surface of the annular plate 4 on the side is formed with fan-shaped recesses (recesses) 41 centered on the vertical center line S in the drawing on the upper side and the lower side thereof. It is formed in an uneven shape having a convex portion 42 at the central portion and the lateral position in the drawing.

The annular plate 16 on the housing 2 side
As shown in FIG. 3, the surface of is a dent portion (concave portion) 161 having the deepest centerline R in the horizontal direction of the drawing, and the centerline S in the vertical direction of the drawing.
In order to form the convex portion 162 having the highest position, the concave and convex portions are formed in four steps in a stepwise manner in the circumferential direction.

Next, the operation of the embodiment will be described. Since the rotary damper of this embodiment is configured as described above, when the rotary shaft 1 and the housing 2 rotate relative to each other, the two annular plates 4 and 16 adjacent to each other rotate relative to each other. 16 When the viscous fluid 12 filled in the gap Y between them is forcibly moved at a flow velocity according to the relative rotational angular velocity, a viscous friction force is generated, and a predetermined damping according to the magnitude of the viscous resistance due to this viscous friction force is generated. Generate force.

(A) During small stroke As shown in FIGS. 2 and 3, the rotary shaft 1 and the housing 2
In the relative rotational neutral position with respect to the concave portion 41 of the annular plate 4 and the convex portion 162 of the annular plate 16, and the convex portion 42 of the annular plate 4 and the concave portion 1 of the annular plate 16.
61 and face each other, and as shown in (a) and (b) of FIG. 4, the gap Y between the two annular plates 4 and 16 is generally large, and therefore the vehicle body vibration stroke Is small, the relative rotation angle of the annular plate 16 on the housing 2 side with respect to the annular plate 4 on the rotating shaft 1 side is small,
Since the minimum value of the gap Y between the two annular plates 4 and 16 is maintained in a large state, the viscous resistance due to the relative rotation becomes low. Therefore, as shown in (a) of FIG. The generated damping force has a small value.

Therefore, since the generated damping force characteristic with respect to the relative rotational angular velocity becomes low, it is possible to suppress the vibration transmission to the spring and secure the riding comfort of the vehicle during a small stroke.

(B) Medium stroke When the vibration stroke of the vehicle body is medium and the relative rotation angle from the neutral position of FIGS. 2 and 3 is around 45 °, the convex portion 42 of the annular plate 4 and the annular plate 16 are rotated. Convex part 162
Since the difference in the rotation angle between and becomes closer to each other,
As shown in (b), the minimum value of the gap Y between the two annular plates 4 and 16 is narrowed, so that the viscous resistance of this part due to relative rotation is increased. Therefore, as shown in (b) of FIG. In addition, the generated damping force also increases to an intermediate value.

(C) Large stroke When the vibration stroke of the vehicle body is large and the relative rotation angle from the neutral position in FIGS. 2 and 3 reaches about 90 °, the convex portions 42 of the annular plate 4 and the annular plate 16 are convex. Since it is in a state of facing 162, the minimum value of the gap Y between the annular plates 4 and 16 is narrowed to the minimum as shown in (a) and (b) of FIG. Viscous resistance increases, and as a result, as shown in FIG. 7C, the generated damping force also increases and reaches the maximum value.

As described above, as the relative rotation angle between the rotary shaft 1 and the housing 2 from the neutral position of relative rotation increases, the generated damping force characteristic with respect to the relative rotation angular velocity gradually increases. Can suppress the vibration of the vehicle body and ensure the steering stability of the vehicle.

As described above, in the rotary damper of this embodiment, when the stroke is short, the vibration transmission to the spring is suppressed by a small damping force to ensure the riding comfort of the vehicle and the stroke is increased. As a result, the damping force is gradually increased to suppress the vibration of the vehicle and ensure the steering stability of the vehicle.

(Second Embodiment) Next, a second embodiment of the present invention shown in FIGS. The rotary damper of this embodiment is different from that of the first embodiment in the structure of forming the concave and convex portions, and is the same as that of the first embodiment.
The same components are designated by the same reference numerals, the description thereof will be omitted, and only different points will be described.

FIG. 8 is a sectional view showing a rotary damper according to a second embodiment of the present invention (a sectional view taken along the line GG in FIGS. 9 and 10), and FIGS. 9 and 10 are sectional views taken along the line EE in FIG. It is sectional drawing in and FF line.

That is, in the rotary damper of this embodiment, the relative rotational neutral position between the rotary shaft 1 and the housing 2 is fixed to the annular plate 4 on the rotary shaft 1 side and the annular plate 16 on the housing 2 side (state of FIG. 11). 4 that exactly overlaps at
b and 16b are respectively opened at vertically symmetrical positions with the rotary shaft 1 sandwiched therebetween, and the recessed portions 4b and 16b constitute concave portions of the concave and convex portions in the claims and the other portions constitute convex portions. . In this embodiment, the recessed portion 4b of the annular plate 4 on the rotary shaft 1 side has a wider radial opening width, while the annular plate 16 on the housing 2 side has a wider circumferential opening width. Is formed.

Next, the operation of the embodiment will be described. (A) Small stroke When the vehicle body vibration stroke is small, as shown in FIG. 12, the housing 2 with respect to the annular plate 4 on the rotating shaft 1 side is
Since the relative rotation angle of the annular plate 16 on the side is small and the both recessed portions 4b and 16b are maintained in an overlapping state,
As shown in FIG. 3, since the gap Y between the annular plates 4 and 16 is large in the portion where the recessed portions 4b and 16b face each other, the viscous resistance in this portion is low and the generated damping force is small. Becomes

Therefore, as a whole, as shown in FIG. 16, since the generated damping force characteristic with respect to the relative rotational angular velocity is low, the vibration transmission to the sprung is suppressed during a small stroke, and the ride comfort of the vehicle is reduced. Can be secured.

It should be noted that the minimum damping force is maintained as described above in a minute stroke within the range of the relative rotation angle corresponding to the difference in circumferential width between the recessed portions 4b and 16b, but when it exceeds this range, it gradually increases. The damping force will increase.

(B) Large stroke When the vibration stroke of the vehicle body is large, as shown in FIG. 14, the housing 2 with respect to the annular plate 4 on the rotating shaft 1 side.
Since the relative rotation angle of the annular plate 16 on the side is large and the positions of the both recessed portions 4b and 16b are displaced from each other,
As shown in FIG. 15, since the gap Y between the annular plates 4 and 16 is halved at the recessed portions 4b and 16b, the viscous resistance of this portion becomes high and the generated damping force becomes a large value. .

Therefore, as a whole, as shown in FIG. 16, since the generated damping force characteristic with respect to the relative rotational angular velocity is high, the vibration of the vehicle body is suppressed during a large stroke to ensure the steering stability of the vehicle. can do.

As described above, also in the rotary damper of this embodiment, as in the first embodiment,
At small strokes, a small damping force suppresses vibration transmission to the spring to ensure the ride comfort of the vehicle, and at large strokes, a large damping force suppresses vehicle vibrations to improve vehicle steering stability. The effect that it becomes possible to secure is obtained.

The embodiment has been described above with reference to the drawings. However, the specific structure is not limited to this embodiment, and the present invention is applicable even if there are design changes and the like within the scope not departing from the gist of the present invention. include.

For example, in the embodiment, the lower part of the vehicle is
Although the case where it is provided in the rotary bearing portion of the arm or the like is taken as an example, the present invention can be applied to the case where the relative motion between arbitrary members is attenuated in the rotation direction. Further, in the embodiment, the case where a plurality of both annular plates are provided is shown, but it is also possible to provide one each.

Further, in the embodiment, the depressions 4b and 16b are provided.
Although an example is shown in which the concave and convex portions having (41, 161) as the concave portions are formed, the concave portions 4c and 16c may be formed by holes as shown in FIG. As shown in (b), the recesses 4d and 16d may be formed by press molding. Further, the size and the number of the recesses are arbitrary and can be freely set according to the required damping force characteristics.

[0041]

As described above, in the rotary damper according to the first aspect of the present invention, the housing having the fluid chamber filled with the viscous fluid therein and the housing in the fluid chamber of the housing with respect to the housing. A rotary shaft provided so as to be rotatable relative to each other, and at least a pair of plates respectively provided on the outer circumference of the rotary shaft and the inner circumference of the housing in the fluid chamber, the side surfaces of the two plates facing each other with a predetermined gap. By forming a concave-convex portion in a direction orthogonal to the facing surface in the circumferential direction with respect to the rotating surface centering on the rotation axis, the facing surfaces of the both plates,
Since the gap between the facing surfaces of both plates is changed depending on the relative rotation position of both plates, it is possible to change the generated damping force characteristics depending on the relative rotation position of both plates. .

Further, in the rotary damper of the second aspect, when the relative rotation angle from the relative rotational neutral position between the housing and the rotary shaft is small, the gap between the facing surfaces of both plates becomes large, and Since the gap between the facing surfaces of both plates becomes small when the rotation angle is large, the unevenness of the facing surfaces of both plates is formed, so that the vibration transmission to the spring is suppressed by a small damping force during a small stroke. As a result, the ride comfort of the vehicle can be ensured, and the vibration of the vehicle can be suppressed by a large damping force at the time of a large stroke to ensure the steering stability of the vehicle.

[Brief description of drawings]

FIG. 1 is a sectional view showing a rotary damper according to a first embodiment of the present invention (a sectional view taken along line D-D in FIGS. 2 and 3).

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

3 is a cross-sectional view taken along the line CC of FIG.

FIG. 4 is a view showing a mutual distance between both plates in a small stroke of the rotary damper according to the first embodiment of the present invention, in which (a) is a view seen from a lateral center line R direction in FIGS. 2 and 3; ) Is a view seen from the vertical centerline S direction in FIGS. 2 and 3.

FIG. 5 is a view showing a mutual distance between both plates at the time of intermediate stroke in the rotary damper according to the first embodiment of the present invention, in which (a) is a view seen from the lateral center line R direction in FIGS. ) Is a view seen from the vertical centerline S direction in FIGS. 2 and 3.

FIG. 6 is a diagram showing a mutual distance between both plates at the time of a large stroke in the rotary damper according to the first embodiment of the present invention, in which (a) is a view seen from the lateral center line R direction in FIGS. ) Is a view seen from the vertical centerline S direction in FIGS. 2 and 3.

FIG. 7 is a characteristic diagram of damping force with respect to relative rotational angular velocity in the rotary damper according to the first embodiment of the present invention.

FIG. 8 is a sectional view (a sectional view taken along the line GG in FIGS. 2 and 3) showing a rotary damper according to a second embodiment of the present invention.

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

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

FIG. 11 is an operation explanatory view showing a relative rotational neutral position in the rotary damper according to the second embodiment of the present invention.

FIG. 12 is an operation explanatory view showing a small stroke state in the rotary damper according to the second embodiment of the present invention.

FIG. 13 is an enlarged sectional view of an essential part taken along the line HH of FIG.

FIG. 14 is an operation explanatory view showing a large stroke state in the rotary damper according to the second embodiment of the present invention.

15 is an enlarged cross-sectional view of a main part taken along the line KK of FIG.

FIG. 16 is a characteristic diagram of damping force with respect to relative rotational angular velocity in the rotary damper according to the second embodiment of the present invention.

FIG. 17 is a cross-sectional view of a main portion showing another embodiment (a) and (b) of the annular plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating shaft 2 housing 4 annular plate (plate) 4b recessed portion (recessed portion of uneven portion) 4c recessed portion 4d recessed portion 6 stud (rotating shaft) 12 viscous fluid 16 annular plate (plate) 16b recessed portion (recessed portion of uneven portion) 16c recessed portion 16d Recessed portion A Hollow chamber (fluid chamber) Y Gap 41 Recessed portion (recessed portion of uneven portion) 161 Recessed portion (recessed portion of uneven portion) 42 Convex portion of uneven portion 162 Convex portion of uneven portion

Claims (2)

[Claims] 1. A housing having a fluid chamber in which a viscous fluid is filled, a rotary shaft rotatably provided in the fluid chamber of the housing relative to the housing, and an outer periphery of the rotary shaft in the fluid chamber and the housing. At least a pair of plates which are respectively provided on the inner periphery of the plate and have their side surfaces facing each other with a predetermined gap, and the facing surfaces of the plates have a rotation surface centered on a rotation axis. On the other hand, by forming a concavo-convex portion in the direction orthogonal to the facing surface in the circumferential direction, the gap between the facing surfaces of both plates is changed depending on the relative rotation position of both plates. And a rotary damper. 2. When the relative rotation angle between the housing and the rotating shaft from the relative rotation neutral position is small, the gap between the facing surfaces of both plates is large, and when the relative rotation angle is large, the facing surfaces of both plates are opposite to each other. So that the gap between
The rotary damper according to claim 1, wherein concavo-convex portions are formed on both plate facing surfaces.