JPH0526286A - Damping force adjustment type buffer - Google Patents

Abstract

PURPOSE:To prevent the generation of impact noise during switching of a damping force. CONSTITUTION:A slope 34 radially inclined toward an edge 33b is formed on an opening edge part 33a extending along the rotation direction of a shutter 32. By rotating the shutter 32, a covering amount of the slope 34 with which an orifice 30a is covered, namely, passage fluid of fluid through the orifice 30a is gradually changed and switched to a state wherein a damping force is low or high. Since passage resistance of the fluid is gradually changed, impact noise is prevented from being generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force adjusting type shock absorber used for vehicles and the like.

[0002]

2. Description of the Related Art Conventionally, there is a hydraulic shock absorber shown in FIGS. 3 and 4 as an example of a damping force adjusting shock absorber. In the figure, a cylinder body 1 comprises an inner cylinder (inner cylinder) 2 and an outer cylinder (outer cylinder) 3, and a piston 4 is provided in the inner cylinder 2.
Is slidably stored, and by this piston 4,
The inside of the inner cylinder 2 is divided into first and second chambers 5 and 6. The piston 4 has a cylindrical piston rod 7 having a communication hole 7a formed in a side wall thereof for communicating the inside and the outside with one end portion thereof.
It is attached to the piston 4 by inserting the 7b side into the piston 4. In this case, one end of the piston rod 7
7b is projected into the second chamber 6, the other end 7c is projected outside the cylinder body 1, and the communication hole 7a is located in the first chamber 5. At one end 7b of the piston rod 7, a tubular guide member 8 having an orifice 8a for communicating the inside and the outside with a side wall is attached via an attachment member 8A. The internal space of the guide member 8 and the through hole 7d of the piston rod 7 communicate with each other, and a lid member 9 is attached to the opening of the guide member 8 on the second chamber 6 side.

On the other hand, a control rod 10 driven by an actuator (not shown) is rotatably inserted in the through hole 7d of the piston rod 7, and the end portion of the control rod 10 has a cylindrical shape. A shutter 11 is attached to the guide member 8 so as to be slidably rotatable. The side wall of the guide member 8 is formed with an orifice 8a that connects the inside and the outside. An opening 12 is formed in the side wall of the shutter 11 so as to correspond to the orifice 8a. In the figure, 13 is a piston side damping force generating mechanism including an orifice 14 formed in the piston 4 and a disc valve 15, and 16 is an orifice 17 provided on the bottom side.
And a bottom side damping force generating mechanism including a disc valve 18.

The hydraulic shock absorber constructed as described above is used by fixing the other end portion 7c of the piston rod 7 and the cylinder body 1 to the vehicle body and the axle side, respectively. And
In the extension stroke, the oil liquid flows on the right side in FIG. 4 as indicated by the solid arrow A, and in the contraction stroke, the oil liquid flows on the left side in FIG. The damping force generating mechanism 13, the bottom side damping force generating mechanism 16, the orifice 8a, the shutter 11 and the like generate a damping force to reduce the impact on the vehicle body. In order to obtain a larger damping force than the state shown in FIG. 4, the shutter 11 is rotated by the operation of the control rod 10 to remove the opening 12 from the orifice 8a and the orifice 8a.
Is closed so that the oil liquid does not pass through the orifice 8a to obtain a large damping force. By rotating the shutter 11 so that the opening 12 coincides with the orifice 8a from the state in which the large damping force is obtained, the state is returned to the state in FIG. 4 described above and the state in which the small damping force is obtained can be obtained. .

[0005]

By the way, in the hydraulic shock absorber described above, the edge of the opening 12 is rotated by the rotation of the shutter 11.
12a passes through the orifice 8a so that the orifice 8a
Is to be opened or closed. For this reason, when the damping force is adjusted, the passage resistance of the oil liquid changes abruptly, and the damping force changes abruptly, which causes an impact sound. As a countermeasure against this, a plurality of orifices are provided on the guide member 8 while being slightly displaced in the circumferential direction, and the orifice area is gradually changed when the shutter 11 is rotated to gradually change the passage resistance of the oil liquid. As a result, it is possible to gradually change the damping force to prevent the generation of impact noise. However, in this case, there has been a problem that the number of man-hours for processing the orifice increases, and as the number of orifices increases, the entire apparatus becomes expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a damping force adjustable shock absorber which does not generate an impact noise when switching the damping force and can be manufactured at low cost.

[0007]

In order to achieve the above-mentioned object, the present invention connects two chambers in a cylinder defined by a piston with a main orifice and a sub-orifice,
A damping force adjusting shock absorber for controlling the flow of fluid passing through a main orifice by a damping force generating mechanism to generate a damping force, and for opening and closing a sub orifice by a shutter rotated by an actuator to adjust the damping force, The opening edge portion along the rotation direction of the shutter is provided with an inclined surface inclined inward in the radial direction toward the edge.

[0008]

With this structure, the opening of the shutter coincides with the orifice, and the passage resistance of the fluid through the orifice is the smallest. By rotating the shutter in this state, the inclined surface with respect to the orifice is formed. Is gradually covered and the passage resistance of the fluid through the orifice gradually increases, and when the opening part departs from the orifice, the passage resistance of the fluid through the orifice becomes the largest and the maximum damping force is obtained. By rotating the shutter in the opposite direction from this state, the covering amount of the inclined surface with respect to the orifice is reduced and the passage resistance of the fluid through the orifice is gradually reduced. It is possible to switch to a state in which the passage resistance through is minimized and the minimum damping force is obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A hydraulic shock absorber according to an embodiment of the present invention will be described below with reference to FIG.
The description will be made with reference to FIGS. 1 and 2. This hydraulic shock absorber has a cylinder body 1 composed of an inner cylinder (inner cylinder) 2 and an outer cylinder (outer cylinder) 3, and the inside of the inner cylinder 2 is divided into first and second chambers 5 and 6. The piston 4 is slidably accommodated, and the piston 4 has a cylindrical piston rod 7 having a communication hole 7a formed in the side wall thereof for communicating the inside and the outside, and the through hole 7d is located in the first chamber 5. Let one end
7b is inserted and projected into the second chamber 6, and the other end 7c
Is mounted outside the cylinder, and the piston side damping force generating mechanism 13 and the bottom side damping force generating mechanism 16 are provided, which has the same configuration as that shown in FIG.

A cylindrical guide member 30 is attached to one end 7b of the piston rod 7 via an attaching member 8A.
The internal space of the guide member 30 and the through hole 7d of the piston rod 7 are communicated with each other via a check valve 60 provided in the opening of the guide member 30 on the piston rod 7 side,
A lid member 9A is attached to the opening of the 30 on the side of the second chamber 6.

On the other hand, a control rod 31 rotatably driven by an actuator (not shown) is rotatably inserted in the through hole 7d of the piston rod 7, and one end portion 31a of the control rod 31 has a cylindrical shape. A shutter 32 is attached to the guide member 30 so as to be slidably rotatable. A pair of orifices 30a for communicating the inside and the outside are formed on the side wall portion of the guide member 30 on the side of the lid member 9A,
An orifice 70 is formed in a side wall portion of the guide member 30 on the check valve 60 side. An opening 33 is formed in the side wall of the shutter 32 so as to correspond to the orifice 30a.

The opening edge portion 33a along the rotation direction of the shutter 32 has a substantially blade-like shape which is tapered toward the edge 33b. With this structure, an inclined surface 34 is formed on the guide member 30 side of the opening edge portion 33a so as to incline radially inward toward the edge 33b.

The hydraulic shock absorber thus constructed is used, for example, by fixing the other end portion 7c of the piston rod 7 and the cylinder body 1 to the vehicle body and the axle side, respectively. And
As shown in FIG. 1, the opening 33 is made to coincide with the orifice 30a. In this state, in the extension stroke, the oil liquid flows as shown by the solid arrow C on the right side of FIG. In FIG. 1, the oil liquid flows on the left side of FIG. 1 as indicated by the one-dot chain line arrow D, and the piston side damping force generating mechanism 13,
The bottom side damping force generation mechanism 16, the orifice 30a, and the shutter 32 generate a damping force to reduce the impact applied to the vehicle body. In this case, in the extension stroke,
While the oil liquid passes through the orifice 70, the oil liquid is prevented from passing through the orifice 70 in the contraction stroke,
Further, the opening area of the orifice 70 is set smaller in advance than the opening area of the orifice 30a in each stroke so that a larger damping force can be obtained in the extension stroke than in the contraction stroke.

In order to obtain a larger damping force than the state shown in FIG. 1, the shutter 32 is rotated in the direction of arrow G, for example, by operating the control rod 31. In this case, when the sloping surface 34 reaches the orifice 30a, the sloping surface 34 gradually covers the orifice 30a, and the orifice 30a is gradually narrowed and the damping force gradually increases. By gradually changing the magnitude of the damping force in this way, no impact noise is generated.

The shutter 32 closes the orifice 30a when the inclined surface 34 is separated from the orifice 30a, and the maximum damping force is obtained. Also, by rotating in the same direction as above (direction of arrow G) or returning in the opposite direction (direction of arrow H), the amount of covering of the inclined surface 34 with respect to the orifice 30a is gradually reduced and gradually attenuated. The magnitude of the force becomes small, and finally, as shown in FIG. 1, the opening 33 coincides with the orifice 30a and the magnitude of the damping force is set to the minimum. Also in this case, the magnitude of the damping force gradually changes, and no impact noise is generated.

In this structure, in order to smoothly switch the damping force, it is not necessary to disperse a plurality of orifices in the guide member 30 while slightly shifting them in the circumferential direction, and it is possible to reduce the number of machining steps accordingly. Moreover, along with this, the cost of the entire apparatus can be reduced.

The inclined surface 34 may be formed over the entire length of the opening edge portion 33a along the rotation direction of the shutter 32 in the direction perpendicular to the paper surface of FIG. 1, or only at the portion facing the orifice 30a. You may do it. Further, in the above embodiment, the switching of the damping force by the orifice 30a is
One stage, in other words, the case of switching only between hard and soft is taken as an example, but further, by forming a plurality of orifices having different diameters in the circumferential direction on the side wall portion of the guide member 30, two stages are provided. The damping force may be switched over the above.

[0018]

According to the damping force adjusting type shock absorber of the present invention,
Switching of the damping force is achieved by gradually changing the passage resistance of the fluid through the orifice, so that no impact noise is generated. Further, in order to smoothly switch the damping force, it is not necessary to provide a large number of orifices in the guide member, the processing man-hours can be reduced accordingly, and the cost of the entire apparatus can be reduced accordingly.

[Brief description of drawings]

FIG. 1 is a sectional view (a sectional view taken along the line II in FIG. 2) showing a damping force adjusting type shock absorber according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the damping force adjusting shock absorber.

FIG. 3 is a sectional view showing an example of a shutter of a conventional hydraulic shock absorber.

FIG. 4 is a sectional view showing a hydraulic shock absorber using the shutter.

[Explanation of symbols]

 2 Inner cylinder 5 1st chamber 6 2nd chamber 30a Orifice 32 Shutter 33a Opening edge 33b Edge 34 Sloping surface

Claims (1)

Claim: What is claimed is: 1. A main orifice and a sub orifice communicate two chambers in a cylinder defined by a piston,
A damping force adjusting shock absorber for controlling the flow of fluid passing through a main orifice by a damping force generating mechanism to generate a damping force, and for opening and closing a sub orifice by a shutter rotated by an actuator to adjust the damping force, A damping force adjustment type shock absorber, characterized in that an inclined surface inclined inward in a radial direction toward the edge is provided at an opening edge portion along the rotation direction of the shutter.