JP3163499B2 - Damping force adjustable hydraulic shock absorber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a damping force-adjustable hydraulic shock absorber, and more particularly to a damping force-adjustable hydraulic shock absorber that reduces shock when switching damping force.

(Prior Art) As a conventional technique, there is a hydraulic shock absorber disclosed in Japanese Utility Model Publication No. Sho 62-136644 filed by the present applicant and published. No.
FIG. 10 to FIG. 11 illustrate and explain the technique.

Reference numeral 1 denotes an inner cylinder (cylinder) provided in an outer cylinder (not shown) and filled with an oil liquid, into which the piston rod 2 having one end protruding from the outer cylinder and the inner cylinder 1 is inserted. Have been. A piston 3 is provided at the other end of the piston rod 2, and the inside of the inner cylinder 1 is defined by two and four oil chambers.

An insertion hole 6 is provided in the piston rod 2,
Between the two oil chambers 4, 5 defined by the piston 3;
The oil passage 7 communicates through the insertion hole 6.

An orifice tube 8 is provided in the middle of the oil passage 7. The orifice tube 8 has a damping force when the oil liquid flows from the oil chamber 4 to the oil chamber 5 through the oil passage 7 when the piston rod 2 extends. Expansion orifices 9A, 9B, 9C and 9D, and contraction side orifices that generate a damping force when the oil liquid flows from oil chamber 5 to oil chamber 4 via oil passage 7 when piston rod 2 is contracted. 10A, 10B, 10C, 10D, 11A, 11B, 11C, and 11D are provided.

As shown in FIG. 11, the extension side orifices 9A and 9B
Are provided so as to substantially oppose each other, and 9A is θ from the straight line l1.
1, 9B are arranged at positions shifted by θ2 from the straight line l1.

Similarly, the extension-side orifices 9C and 9D are provided so as to substantially oppose each other, and the extension-side orifice 9C is disposed at a position deviated by θ3 from the straight line l2, and the extension-side orifice 9D is disposed at a position deviated by θ4 from the line l2.

Compression orifices 10A to 10D, 11A to 11D are also 11th
As shown in the figure, the orifices 9A to 9D are provided at positions similar to those in the circumferential direction.

Inside the orifice tube 8, a rotation operation is performed from the upper end side of the piston rod 2 via an adjustment rod 12,
A shutter member 13 provided with a pair of openings 14 for selecting and communicating the extending or contracting orifices 9A to 9D, 10A to 10D and 11A to 11D provided in the orifice cylinder 8.
Is provided.

In the damping force adjusting type hydraulic shock absorber configured as described above,
The opening 14 of the shutter member 13 is located between the orifices 9A and 9D and 9
B, 9C, that is, as shown in FIG. 11, a straight line l3
It generates a high damping force when it is located above, a middle damping force when it is located at the orifices 9A and 9B, and a low damping force when it is located at the orifices 9C and 9D.

When the damping force changes from a high damping force to an intermediate damping force,
The shutter member 13 rotates in the direction of arrow E, and the opening 14
First, the orifices 9A, 10A, and 11A are opened, and the orifices 9B, 10B, and 11B are opened later.

As a result, the damping force characteristic with respect to the rotation angle of the shutter member changes relatively slowly.

When the damping force changes from the intermediate damping force to the low damping force, the shutter member 13 rotates in the direction of arrow E, and
14 starts opening the orifices 9C, 10C, 11C first, and then opens the orifices 9D, 10D, 11D with a delay. And the orifice
During opening of 9C, 10C, 11C and orifices 9D, 10D, 11D, orifices 9A, 10A, 11A first begin to close, and the orifices are delayed.
9B, 10B, and 11B are closed.

As a result, the damping force characteristic with respect to the rotation angle of the shutter member changes relatively slowly as when the damping force changes from a high damping force to an intermediate damping force.

(Problems to be Solved by the Invention) In the above-described conventional technology, although the damping force characteristic at the time of switching can be changed relatively slowly, the pair of orifices facing each other is shifted in the rotation direction of the shutter member. The transitional rotation angle of the shutter until the damping force changes from one damping force to another damping force at the time of switching of the shutter is determined by the diameter of the pair of opposing orifices and the deviation thereof. There was a limit to taking large.

As a result, when the shutter is rotated at a high speed, the damping force changes abruptly, and a shock may occur at the time of switching.

Further, in the above-described conventional technology, when the opening 14 of the shutter member 13 changes from the intermediate damping force located at the orifices 9A and 9B to the low damping force located at the orifices 9C and 9D, the orifices 9A and 9B After the blockage, the orifices 9C and 9D begin to open, so that when changing to a low damping force, there is a problem that the damping force temporarily increases.

SUMMARY OF THE INVENTION The present invention provides a damping force-adjustable hydraulic shock absorber that can minimize a shock at the time of damping force switching.

(Means for Solving the Problems) In order to solve the above problems, in the invention of claim 1, a cylinder filled with an oil liquid, one end is inserted into the cylinder, and the other end is the cylinder. A piston rod protruding outward, attached to one end of the piston rod,
A piston defining two oil chambers in the cylinder, an oil passage communicating between the oil chambers defined by the piston,
A plurality of orifices provided in the oil passage and provided to enable selection of a plurality of damping force characteristics, an opening for opening the plurality of orifices, and a wall for closing the orifice are provided, And a shutter member for selecting a damping force characteristic by selectively opening and closing the plurality of orifices.In the damping force adjustable hydraulic shock absorber, when the damping force characteristic is lowered, one orifice is closed by the shutter member. While opening another orifice having a larger opening area than the one orifice, the plurality of orifices are arranged so that the total area of the orifices opened increases as the shutter member moves.

According to the invention of claim 2, the cylinder filled with the oil liquid, one end inserted into the cylinder, the other end protruding outside the cylinder, and attached to one end side of the piston rod A piston defining two oil chambers in the cylinder, an oil passage communicating between the oil chambers defined by the piston, and a plurality of damping force characteristics provided in the oil passage. A plurality of orifices provided for opening and closing the plurality of orifices, and a shutter member for selecting a damping force characteristic by selectively opening and closing the plurality of orifices. And the orifice opened by the opening portion when selecting one damping force characteristic is an orifice group consisting of a plurality of orifices. When the shutter member is moved from the orifice group to another orifice group having a larger total area than the one orifice group and the damping force is switched to be low, by closing one orifice group and simultaneously opening the other orifice group, As the shutter member moves,
The plurality of orifices are arranged so that the total area of the orifices opened by the opening increases.

According to the third aspect of the invention, the one orifice group includes three or more orifices, and the centers of the three or more orifices are shifted from each other in the moving direction of the opening.

According to a fourth aspect of the present invention, the total area of the orifice opened by the opening along with the movement of the shutter member is increased in inverse proportion to the square root of the moving amount of the shutter member.

According to the first aspect of the invention, when the damping force is reduced, the shutter member closes one orifice and opens another orifice having a larger opening area than the one orifice. Since the total area of the orifice opened by the opening always increases as the shutter member moves, the damping force does not increase once when the damping force is reduced.

According to the second aspect of the present invention, when the damping force is reduced, the one orifice group is closed and the other orifice group is opened at the same time, so that the opening is opened by the opening as the shutter member moves. Since the total area of the orifices increases, the damping force does not temporarily increase, and the damping force changes smoothly.

Furthermore, in the invention of claim 3, since the orifice group is made up of three or more orifices, and the centers of the three or more orifices are shifted in the moving direction of the opening, the orifices are provided.
When switching the damping force, the damping force changes more smoothly.

According to the fourth aspect of the invention, since the total area of the orifice increases in inverse proportion to the square root of the moving amount of the shutter member, the damping force changes in proportion to the moving amount of the shutter member.

(Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, reference numeral 20 denotes an inner cylinder (cylinder) provided in an outer cylinder (not shown) and filled with an oil liquid, and one end of the inner cylinder protrudes from the outer cylinder and the inner cylinder 20 and extends in the axial direction. A piston rod 22 provided with an insertion hole 21 is inserted.

A small diameter portion 23 is formed at the other end of the piston rod 22, and a piston 26 that defines the inside of the inner cylinder 20 into two oil chambers 24 and 25 is fixed to the small diameter portion 23.

The piston 26 is provided with two types of communication passages 27A and 27B that communicate between the two oil chambers 24 and 25.

The oil chamber 2 is located above the piston 26 through the communication passage 27A.
A compression-side disk valve 28 including a plurality of disks that generates a damping force when the oil liquid flows from 5 to the oil chamber 24 is provided. Above the disc valve 28, a retainer 30 that regulates bending of the disc valve 28 via a spacer 29 is provided.

An extension-side disc valve 31 including a plurality of discs that generates a damping force when the oil liquid flows from the oil chamber 24 to the oil chamber 25 via the communication passage 27B is provided below the piston 26. I have.

A fixed orifice 32 is provided on the piston-side disk of the disk valve 31. Disc valve
A retainer 34 that regulates the bending of the disk valve 31 via a spacer 33 is provided below the lower portion 31.

Each member provided on the small diameter portion 23 of the piston rod 22 is fixed by a cylindrical member 35.

 Next, the damping force adjusting mechanism will be described.

A communication passage 36 is provided in the piston rod 22, and communicates the insertion hole 21 with the oil chamber 24. Further, the cylindrical member 35
A communication hole 37 that communicates the oil chamber 25 with the inside of the tubular member 35 is provided at a side portion of the cylinder member 35. As a result, the oil chambers 24 and 25
Oil passage constituted by communication hole 36, insertion hole 21, and communication hole 37
Connected by 38.

An orifice tube 40 in which a reduced diameter portion 39 whose outer diameter is reduced is formed in the upper portion of the cylindrical member 35 so as not to flow the oil liquid between the cylindrical member 35 and the reduced diameter portion 39. An oil chamber 41 is formed between the two.

Above the orifice tube 40, a reduced diameter portion 39 and a cylindrical member 35 are provided.
An upper orifice group 42 is provided so as to connect the oil chamber 41 between the oil chamber 41 and the inside of the orifice cylinder 40. A group 43 and a lower orifice group 44 are provided.

A one-way valve 45 is provided at the upper part of the orifice cylinder 40 to allow the flow of the oil liquid from the inside of the orifice cylinder 40 to the insertion hole 21 in the piston rod 22 and block the reverse flow. Is provided with a notch 46 that always allows the flow of the oil liquid between the insertion hole 21 in the piston rod 22 and the oil chamber 41.

On the inside of the orifice cylinder 42, a pair of openings 47 provided in the axial direction to open the orifice groups 42, 43, 44 in a cylindrical shape on the side walls thereof, and the orifice groups 42, A shutter member 49 including a wall portion 48 provided for closing the 43 and 44 is rotatably provided.

A lower end of an adjustment rod 50 for rotating the shutter member 49 is fixed to an upper portion of the shutter member 49, and the adjustment rod 50 projects outside the piston rod 22 through the insertion hole 21 in the piston rod 22, and is The shutter member 47 can be operated by an actuator or the like.

Next, the arrangement of the orifices of the orifice groups 42, 43, and 44, which are essential parts of the present invention, and the damping force characteristics thereof will be described with reference to FIGS.

As shown in FIG. 2, an upper orifice group 42 that generates a damping force when the piston rod 22 is extended includes a pair of orifices opened by a pair of openings 47 of the shutter member 49 when a low damping force is generated. Groups 60A, 60B, and a pair of openings of the shutter member 49 when generating an intermediate damping force
It is composed of a pair of orifice groups 61A and 61B opened by 47.

Between the orifice group 60A and the orifice group 61B, between the orifice group 60B and the orifice group 61A, between the orifice group 60B and the orifice group 61A, there is no orifice-less orifice part 62A, which is selected when selecting a high damping force.
62B is provided.

Here, when the orifices of the orifice groups 61A and 61B switch from a high damping force to an intermediate damping force due to the rotation of the shutter member 49, as shown in FIG. They are provided so as to have a substantially proportional relationship. That is, since the damping force is generally inversely proportional to the square of the opening area of the orifice, the change in the area of the orifice to be opened may be substantially inversely proportional to the square root of the rotational displacement of the shutter member. For this reason, as shown in FIG. 5, the orifices of the orifice groups 61A and 61B are provided so as to increase in diameter in order, and the change in the orifice area opened by the opening 47 is the square root of the rotational displacement of the shutter member 49. Is almost inversely proportional to The orifices of the orifice groups 61A and 61B are arranged so as to alternately overlap so that the damping force changes smoothly, and are sequentially opened when the shutter is switched. The total area of the orifice groups 61A and 61B is set to a size necessary to generate an intermediate damping force.

Each orifice of the orifice group 60A, 60B is provided so that the wall 48 starts to close the orifice group 61A, 61B and is opened by the opening 47 at the same time when switching from the intermediate damping force to the low damping force. Then, as shown in FIG. 6, the orifice groups 60A and 60B where the opening 47 opens and the orifice where the wall 48 closes so that the change in damping force with respect to the rotational displacement of the shutter member 49 is substantially proportional. Group 6
The change in the area of the orifice due to 1A, 61B is set so as to be substantially in inverse proportion to the square root of the rotational displacement of the shutter member 49, and therefore the orifice groups 60A, 60B are provided so that the diameter increases in order. The total area is large enough to generate a low damping force.

Next, the orifice groups 43 and 44 that generate a damping force when the piston rod 22 contracts will be described.

As shown in FIG. 3, similarly to the orifice group 42, the middle orifice group 43 includes a pair of orifice groups 63A and 63B that generate a low damping force, and a pair of orifice groups 64A and 64B that generate an intermediate damping force. It is composed of Similarly, the lower orifice group 44 includes a pair of orifice groups 65A and 65B that generate a low damping force and a pair of orifice groups 66A and 66B that generate an intermediate damping force, as shown in FIG. Have been.

Between the orifice group 63A and the orifice group 64B, and between the orifice group 63B and the orifice group 64A, there is no orifice part 67 without an orifice selected when selecting a high damping force.
A and 67B are provided. Similarly, between the orifice group 65A and the orifice group 66B and between the orifice group 65B and the orifice group 66A, orifice-free orifice portions 68A and 68B without orifices selected when selecting a high damping force are provided. ing.

When the orifices of the orifice groups 64A, 64B, 66A and 66B switch from a high damping force to an intermediate damping force by rotation of the shutter member 49, as shown in FIG.
In order that the change in damping force with respect to the rotational displacement of the shutter member 49 has a substantially proportional relationship, as shown in FIG. 7, the diameters are sequentially changed so that the change in the opening area is substantially inversely proportional to the square root of the rotational displacement of the shutter member 49. It is provided with a large size, and its total area is set to be large enough to generate an intermediate damping force. The orifices of the orifice groups 64A, 64B, 66A, 66B are arranged so as to alternately overlap with each other, and are sequentially opened when the shutter is switched.

Similarly, each of the orifices of the orifice group 63A, 63B, 65A, 65B also switches when switching from intermediate damping force to low damping force.
The wall portion 48 is provided so as to open at the same time as closing the orifice group 64A, 64B, 66A, 66B, and when switching from the intermediate damping force to the low damping force, as shown in FIG. The orifice group 63A, 63B, 64A, 64B, 65A, 65B, so that the damping force change with respect to the rotational displacement is substantially proportional.
The change in the area of 66A, 66B is set so as to be substantially inversely proportional to the square root of the rotation angle of the shutter member 49. Therefore, the orifices of the orifice groups 63A, 63B, 65A, 65B are provided so that the diameters increase in order. And the total area is large enough to generate a low damping force.

Thus, the orifice group 60A, 60B, 61A, 61B on the extension side
And orifices 63A, 63B, 64A, 64B, 65A, 65B, 66 on the contraction side
Since A and 66B are set so that the change in damping force with respect to the rotational displacement of the shutter member 49 is substantially in inverse proportion, when switching from one damping force characteristic to another damping force characteristic, an intermediate point of switching of the shutter member 49 is used. The damping force at the position is intermediate between the damping force before switching and the damping force after switching.

Note that the relationship between the orifice group 42 on the extension side and the orifice groups 43 and 44 on the contraction side is such that, regardless of the position of the opening 47 of the shutter member 49, the total area of the orifices opened by the orifice group 42 is The total area of the opened orifices of the orifice groups 43 and 44 is smaller.

The operation of the damping force adjusting type hydraulic shock absorber having the above structure will be described below.

When the piston speed is low when the piston rod 22 is extended, the oil liquid in the oil chamber 24 passes through the communication passage 27B and the fixed orifice 32
Generates a damping force and flows into the oil chamber 25. With this flow, the oil liquid in the oil chamber 24 flows through the communication hole 36 to the insertion hole 21 in the piston rod 22. Notch provided on one-way valve 45
46, the orifice opened from the oil chamber 41 by the opening 47 of the upper orifice group 42, the inside of the orifice cylinder 40, the orifice opened by the opening 47 of the orifice group 43, 44,
And flows into the oil chamber 25 through the communication hole 37.

At this time, the relationship between the orifice group 42 and the orifice groups 43 and 44 is such that, regardless of the position of the opening 47 of the shutter member 49, the total area of the orifices opened by the orifice group 42 is equal to the orifice groups 43 and 44. Is smaller than the total area of the opened orifices, a damping force is generated by the total area of the opened orifices of the orifice group 42.

When the piston speed increases, the disc valve 31 opens, and a damping force is generated due to the valve characteristic.

Next, when the piston speed is low when the piston rod 22 is contracted, the oil liquid in the oil chamber 25 generates a damping force through the fixed orifice 32 and flows into the oil chamber 24 via the communication passage 27B. With this flow, the oil liquid in the oil chamber 25 passes through the communication hole 37, generates a damping force by the orifices opened in the orifice groups 43 and 44, flows into the orifice cylinder 40, and opens the one-way valve 45,
The oil flows into the oil chamber 24 through the insertion hole 21 and the communication hole 36.

When the piston speed increases, the disc valve 28 opens, and a damping force is generated due to the valve characteristic.

Next, an operation at the time of switching the damping force, which is a main part of the present invention, will be described.

An opening 47 provided in the shutter member 49 has an orifice-free portion 62A, 62B, 67A, 67B, 68 provided in the orifice cylinder 40.
A, 68B, that is, one of the openings 47 (each having an opening of 60 ° in the present embodiment) is one of FIGS.
When located between 310 degrees and 30 degrees, the oil passage 38 is shut off and has a high damping force.

Next, the adjustment rod 50 is rotated, and the opening 47 provided in the shutter member 49 generates an intermediate damping force provided in the orifice cylinder 40. Orifice groups 61A, 61B, 64A, 64B,
When located at 66A, 66B, that is, when one of the openings 47 is located between 30 degrees and 70 degrees in FIGS. 5 and 7, an intermediate damping force is obtained.

At the time of this switching, the opening 47 gradually starts to open from the small diameter orifice, so that the damping force changes smoothly as shown in FIG. 6 and FIG.

Further, by further rotating the adjustment rod 50, the shutter member
An orifice group 60A, 60B, 63A, 63 in which an opening 47 provided in 49 is provided in the orifice cylinder 40 and generates a low damping force.
B, 65A, 65B, that is, one of the openings 47 is the fifth
When located between 90 degrees and 130 degrees in the figures and FIG. 7, the damping force is low.

At the time of this switching, the opening 47 gradually closes from the small-diameter orifices of the orifice groups 61A, 61B, 64A, 64B, 66A, 66B that generate an intermediate damping force, and at the same time, generate a low damping force. Orifices 60A, 60B, 63A, 63B, 65A,
Start opening gradually from the small orifice of 65B. At this time, the orifice groups 61A, 61B, 64 that generate an intermediate damping force
Orifice group 60 that generates low damping force of A, 64B, 66A, 66B
Regarding the relationship with A, 60B, 63A, 63B, 65A, 65B, no matter where the opening 47 of the shutter member 49 is located, the area of the orifice to be opened is smaller than the area of the orifice to be closed. Is large, the total area of the orifices that are open increases, and the damping force decreases smoothly as shown in FIGS. 6 and 8.

The same applies to the case where the shutter member is reversed to increase the damping force.

In the first embodiment, an example in which orifices having different diameters are arranged in order is used. However, the present invention is not limited to this, and even if orifices having different diameters are provided separately, the attenuation may be reduced. Any arrangement may be used as long as the change in the force is smoothly changed.

Further, in the first embodiment, the opening area is changed so as to be almost inversely proportional to the square root of the rotation angle so that the rotation angle of the shutter member and the damping force are substantially proportional to each other. However, this approximately proportional relationship is not exact because a plurality of orifices are used. However, when changing from one damping force characteristic to another damping force characteristic, the upper and lower sides of the damping force obtained from the almost proportional relationship of the ideal state are changed.
% Is desirable because it causes a smooth change in damping force at the time of switching.

Further, in the first embodiment, an example is shown in which the present invention is used for any change from high damping force to low damping force. However, the present invention may be provided only where vibration or abnormal noise is likely to occur. .

Next, the shutter member 49 of the first embodiment and the orifice cylinder
In the second embodiment in which the arrangement of the orifice group provided in 40 is modified, only the relationship between the orifice and the shutter is described in ninth embodiment.
This is shown in the drawing and described.

Reference numeral 70 denotes a cylindrical orifice cylinder, and the orifice cylinder 70 has common orifices 71A, 71B, 71C on the extension side and the contraction side.
Are provided side by side in the axial direction.

Inside the orifice cylinder 70, a shutter member 73 having a cylindrical shape and provided with an opening 72 for opening the orifices 71A, 71B, 71C is provided.

The opening 72 of the shutter member 73 is provided in a stepwise manner as shown in FIG. 9 so that the orifice opens in the order of 71A, 71B, and 71C as the shutter member 73 rotates. ing.

 The operation of the second embodiment will be described below.

When the shutter member 73 moves in the direction F in FIG. 9 to switch the damping force from the state where the orifices 71A, 71B and 71C are closed by the shutter member 73 and the damping force is high, the opening 72 is used.
Has a step shape, so from the orifice 71A,
The orifice 71B and the orifice 71C are opened.

 The closing of the orifice is performed similarly to the opening.

In the second embodiment, the shutter member 73 having an opening 72 on the stairs is used, and the opening timing of the orifice is shifted by the opening. It may be provided diagonally from the direction to the circumferential direction, and may not be particularly on the stairs.

Further, in each of the above embodiments, the example in which the adjusting rod 50 is externally operated by an actuator in the present embodiment has been described. However, the actuator may be provided in the piston rod and driven.

Further, in each of the above embodiments, the example in which the shutter member 49 is rotated is shown. However, the orifice group may be shifted in the axial direction, and the damping force may be switched by operating the shutter member in the axial direction. It is.

Further, in each of the above embodiments, an example using a circular orifice is shown. However, the present invention is not limited to this. As another embodiment, an elliptical hole may be used, and the damping force may be smoothly reduced. A slit having a continuously changing cross-sectional area may be used to change it.

According to the first aspect of the invention, when the damping force is reduced, the shutter member closes one orifice and opens another orifice having an opening area larger than that of the one orifice. As the orifice moves, the total area of the orifice opened by the opening always increases, so that the damping force does not increase once when the damping force is reduced.

According to the second aspect of the present invention, when the damping force is reduced, the one orifice group is closed and the other orifice group is opened at the same time, so that the opening is opened by the opening as the shutter member moves. Since the total area of the orifices increases, the damping force does not temporarily increase, and the damping force changes smoothly.

Furthermore, in the invention of claim 3, since the orifice group is made up of three or more orifices, and the centers of the three or more orifices are shifted in the moving direction of the opening, the orifices are provided.
When switching the damping force, the damping force changes more smoothly.

According to the fourth aspect of the present invention, since the total area of the orifice increases in inverse proportion to the square root of the moving distance of the shutter member, the damping force is reduced by the moving distance of the shutter member. Changes in proportion to

As described above, in the present invention, the change in the damping force is smoothed, so that the shock at the time of switching is reduced, the riding comfort is improved, and the generation of the impact sound generated at the time of switching can be prevented. .

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a damping force adjusting type hydraulic shock absorber according to a first embodiment of the present invention, FIG. 2 is a view showing the arrangement of orifice groups 42 in FIG. 1, and FIG. 1 shows the arrangement of the orifice group 43 in FIG. 1, FIG. 4 shows the arrangement of the orifice group 44 in FIG. 1, and FIG. 5 shows the orifice group 42 in FIG. In the upper row, from 0 ゜ to 180 中 in Fig. 2 From the lower row, 180 ゜
FIG. 6 is a development diagram showing up to 360 °, FIG. 6 is a characteristic diagram showing the relationship between the rotation angle of the shutter member on the extension side and the damping force, and FIG. 7 is a group of orifices 43, in FIGS. 44 is developed in the circumferential direction.
FIG. 8 is a developed view showing 180 ° to 360 ° in the lower stage up to 180 °, FIG. 8 is a characteristic diagram showing a relationship between the rotation angle of the shutter member on the contraction side and the damping force, and FIG. FIG. 10 is a diagram showing a relationship between an orifice and a shutter member of a damping force adjusting type hydraulic shock absorber according to a second embodiment, FIG. 10 is a partial cross-sectional view of a conventional hydraulic shock absorber, FIG. 11 is an orifice 9A, FIG. It is a figure showing arrangement of 9B, 9C, and 9D. 22 Piston rod 26 Piston 24 Oil chamber 25 Oil chamber 38 Oil passage 42 Orifice group 43 Orifice group 44 Orifice group 47 Opening 48 Wall 49 , 70 …… Shutter member 71A, 71B, 71C …… Orifice

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Murata 1116 Koizono, Ayase-shi, Kanagawa Tokiko Co., Ltd. Sagami Plant (56) References JP-A-63-270934 (JP, A) JP-A-62-246638 (JP, A) Japanese Utility Model 2-5629 (JP, U) Japanese Utility Model 60-173738 (JP, U) Japanese Utility Model 62-136644 (JP, U)

Claims (4)

(57) [Claims] A cylinder filled with an oil liquid; a piston rod having one end inserted into the cylinder and the other end protruding out of the cylinder; and a piston rod attached to one end of the piston rod. A piston defined by two oil chambers; an oil passage communicating between the oil chambers defined by the pistons; and an oil passage provided in the oil passage so that a plurality of damping force characteristics can be selected. A plurality of orifices, a shutter member provided with an opening for opening the plurality of orifices and a wall for closing the orifice, and selecting a damping force characteristic by selectively opening and closing the plurality of orifices. In the force-adjusting hydraulic shock absorber, when the damping force characteristic is reduced, the shutter member
While closing one orifice, another orifice having an opening area larger than that of the one orifice is opened, and the plurality of orifices are arranged so that the total area of the orifices opened increases as the shutter member moves. A damping force adjusting type hydraulic shock absorber characterized by the above-mentioned. 2. A cylinder filled with an oil liquid, a piston rod having one end inserted into the cylinder and the other end protruding out of the cylinder, and a piston rod attached to one end of the piston rod. A piston defined by two oil chambers; an oil passage communicating between the oil chambers defined by the pistons; and an oil passage provided in the oil passage so that a plurality of damping force characteristics can be selected. A plurality of orifices, a shutter member provided with an opening for opening the plurality of orifices and a wall for closing the orifice, and selecting a damping force characteristic by selectively opening and closing the plurality of orifices. In the force-adjusting hydraulic shock absorber, when selecting one damping force characteristic, the orifice opened by the opening is an orifice group including a plurality of orifices, and one orifice is formed. When the shutter member is moved to another orifice group having a larger total area than the one orifice group to lower the damping force, the one orifice group is closed and the other orifice group is simultaneously opened to open the other orifice group. A damping force-adjustable hydraulic shock absorber, wherein the plurality of orifices are arranged so that the total area of the orifices opened by the opening increases as the shutter member moves. 3. The apparatus according to claim 2, wherein said one orifice group comprises three or more orifices, and the centers of said three or more orifices are shifted from each other in the moving direction of said opening. Hydraulic shock absorber with adjustable damping force. 4. The apparatus according to claim 1, wherein a total area of said orifice opened by said opening increases with a movement of said shutter member in inverse proportion to a square root of a moving amount of said shutter member. Item 2. The damping force adjustable hydraulic shock absorber according to item 2 or 3.