JPH10259846A - Position-dependent damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position-dependent damper to have the valve characteristics of producing stable extension-side and compression-side damping force over the whole range of the displacement of its pistons from the static balanced position. SOLUTION: A piston rod 11 is mounted with a first piston 14 having an extension-side hard damping valve 21 and a compression-side hard damping valve 22, and a second piston 15 having an extension-side soft damping valve 25 and a compression-side soft damping valve 26, both which pistons are arranged facing toward axial direction in series. A cylinder 2 is contracted at its internal surface on the side of the first piston 14 so as to have a contracted part 9 of the inside diameter equal to the outside diameter of the first and second pistons 14 and 15. The second piston 15 is mounted at its end face facing away from the first piston 14 with a guide member 17 adapted to slide on the internal surface of the cylinder 2 excluding the contracted part 9. The guide member 17 is fitted with the second piston 15 so as to be separatable from the piston 15 by means of a spring 18 interposed between itself and the cylinder 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position-dependent damper for damping various types of vibrating bodies by damping them.

[0002]

2. Description of the Related Art Conventionally, as a position-dependent damper of this type, for example, one shown in FIG. 6 is known.

That is, the position-dependent damper M comprises a piston c having a cylinder a mounted on a piston rod b.
Thus, the upper working oil chamber U on the extension side and the lower working oil chamber L on the compression side are partitioned via the piston seal d on the outer periphery.

[0004] The upper hydraulic oil chamber U and the lower hydraulic oil chamber L are provided on the piston c and open toward the lower hydraulic oil chamber L side. Communicate with each other through a pressure-side damping valve f that opens toward

The outer periphery of the cylinder a is defined as a reservoir chamber R by an outer shell g surrounding the cylinder a, and the reservoir chamber R is passed through a bottom orifice h provided on the lower side wall of the cylinder a. It communicates with the lower hydraulic oil chamber L.

On the other hand, a static equilibrium position of the cylinder a with the piston c (the state of 1G which is a normal use state) X
Is formed on the inner wall surface in the vicinity of the throttle oil passage i having a length extending (straddling) the outer peripheral surface of the piston c by bulging the side wall outward. The piston c
The upper working oil chamber U and the lower working oil chamber L are connected to each other through the throttle oil passage i only when slides.

A bump rubber j is provided above the expansion damping valve e so as to be fitted to the piston rod b. The bump rubber j is attached to the upper end of the cylinder a near the maximum extension of the position-dependent damper M. By hitting a certain bearing k, the occurrence of an impact at the time of maximum elongation is reduced.

Thus, when the position-dependent damper M expands and contracts with the external vibration applied to the vibrating body, the cylinder a
And the piston c cause relative displacement in the axial direction using the bearing k and the piston seal d as guides.

Therefore, the cylinder a and the piston c are now moved from the static equilibrium position X shown in the drawing to the upper hydraulic oil chamber U on the extension side or the lower hydraulic oil chamber L on the compression side through the throttle oil passage i. Assume that displacement has occurred.

At this time, the upper hydraulic oil chamber U and the lower hydraulic oil chamber L communicate with each other through the throttle oil passage i until the upper or lower edge of the piston c passes through the throttle oil passage i in the cylinder a. ing.

For this reason, during this time, regardless of the extension and compression operations, the cylinder a is not pushed and opened by the extension-side and compression-side damping valves e and f of the piston c.
The oil flows between the upper working oil chamber U and the lower working oil chamber L through the throttle oil path i between the bulging portion of the piston and the piston c.

At this time, the shortage and surplus of oil in the cylinder a caused by the retreat and intrusion of the piston rod b (the oil corresponding to the retraction and intrusion volume of the piston rod b) are transferred to the lower hydraulic oil chamber L Compensation is made by exchanging oil between the bottom orifice h and the reservoir chamber R.

In addition, at the same time, during the compression operation,
The oil pressure in the lower hydraulic oil chamber L during the compression operation is secured by the flow resistance of the oil pushed out from the lower hydraulic oil chamber L to the reservoir chamber R through the bottom orifice h.

Thus, the position-dependent damper M generates the expansion-side damping force and the compression-side damping force having a quadratic orifice characteristic by the flow resistance of the oil when passing through the throttle oil passage i. External vibration applied to the vibrating body is damped by the damping force and the compression side damping force.

On the other hand, when the upper end or the lower end edge of the piston c moves to the extension side or the compression side after passing through one end of the throttle oil passage i (over the throttle oil passage i), the piston c causes the throttle oil to move. The opening at one end of the path i is closed, and the communication between the upper hydraulic oil chamber U and the lower hydraulic oil chamber L by the throttle oil path i is blocked.

However, the throttle oil passage i formed by the piston c
Blockage has no effect on the function of compensating for the excess or deficiency of oil at the bottom orifice h due to the expansion / contraction operation of the position-dependent damper M and the function of ensuring oil pressure in the lower hydraulic oil chamber L during the compression operation. Absent.

Therefore, in this case, the extension damping valve e provided on the piston c is pushed open by the extension operation of the position-dependent damper M, and the oil in the upper hydraulic oil chamber U is transferred to the lower hydraulic oil chamber L. The expansion-side damping valve e is pushed out, and the expansion-side damping force of the valve characteristics is generated by the flow resistance of the oil flowing while opening and closing.

In the compression operation, the piston c
The pressure in the lower hydraulic oil chamber L is pushed out to the upper hydraulic oil chamber U by pushing and opening the pressure side damping valve f, and the pressure resistance of the valve characteristic is generated by the flow resistance of the oil flowing by pushing and opening the pressure side damping valve f. Thus, the external vibration applied to the vibrating body is attenuated in cooperation with the above-described extension-side damping force of the valve characteristic.

[0019]

As described above, in the above-described position-dependent damper M of the conventional type, the relative relationship between the cylinder a and the piston c moves beyond the throttle oil path i to the extension side or the compression side. Only when activated, piston c
Act on the expansion side damping valve e and the compression side damping valve f to generate the expansion side and compression side damping forces of the valve characteristics.

However, until the relative relationship between the cylinder a and the piston c exceeds the throttle oil passage i, the throttle oil passage i
The communication between the upper hydraulic oil chamber U and the lower hydraulic oil chamber L prevents the expansion damping valve e and the compression damping valve f of the piston c from being pushed and opened, and the orifice characteristic is determined only by the flow resistance of the oil passing through the throttle oil passage i. The extension side and compression side damping forces will be generated.

As a result, not only does the initial damping force at the time of the expansion / contraction operation of the position-dependent damper M become an orifice characteristic, causing a delay in the rise of the damping force, but also the damping force at the time of the expansion / contraction operation in the low-speed region has the orifice characteristic. As a result, the position-dependent damper M has an inadequate damping effect on the vibrating body, and has an inconvenience that the vibration is hardly settled.

Accordingly, an object of the present invention is to provide a position-dependent damper having a novel structure capable of maintaining the extension-side and compression-side damping forces over the entire displacement from the static balance position in the valve characteristics. It is to be.

[0023]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a first piston having a hard extension damping valve and a hard compression damping valve in a piston rod, a soft extension damping valve and a soft piston. The second pistons with the compression-side damping valves are arranged in series with each other in the axial direction, and the inner wall surface of the cylinder on the first piston side matches the outer diameter of the first and second pistons. A guide member that slides on the inner wall surface of the cylinder except for the reduced diameter portion is disposed on an end surface of the second piston opposite to the first piston, the guide member being squeezed to the reduced inner diameter. By a spring interposed between the cylinder and the second piston so as to be able to come and go with the second piston.

That is, with the above configuration, when the position-dependent damper expands and contracts with external vibration applied to the vibrating body, the guide member is fitted to the second piston by the restoring force of the spring. The inner wall surface of the cylinder is slid in contact with the cylinder to maintain an oil-tight state with the cylinder.

Thus, at the initial stage of the expansion / contraction operation of the position-dependent damper and during the expansion / contraction operation in the low speed range, the gap between the cylinder and the second piston is oil-tightly closed by the guide member and the piston is While guiding the lower end portion of the rod, a bypass oil passage between the first piston and the cylinder is secured until the edge of the first piston reaches the reduced diameter portion of the cylinder.

For this reason, during the extension operation during this time, the soft extension damping valve of the second piston is pushed open while bypassing the first piston by securing the above-mentioned bypass oil passage, thereby opening the upper portion on the extension side. The oil flows from the hydraulic oil chamber to the lower hydraulic oil chamber on the compression side.

At this time, the shortage of oil caused by the retraction of the piston rod from the cylinder is compensated by sucking the oil in the reservoir chamber into the lower hydraulic oil chamber through the bottom orifice.

On the other hand, during the compression operation, on the contrary, an amount of oil corresponding to the volume of penetration of the piston rod is pushed out from the lower hydraulic oil chamber through the bottom orifice into the reservoir chamber, and the bottom orifice is used to push the oil in the lower hydraulic oil chamber. It compensates for the excess oil in the cylinder while ensuring the oil pressure.

Then, while bypassing the first piston by securing the bypass oil passage in the same manner as in the above-described extension operation, the soft pressure-side damping valve of the second piston is pushed open this time to move the upper working oil from the lower working oil chamber. Pour oil into the oil chamber.

Accordingly, the position-dependent damper pushes and opens the soft expansion damping valve and the soft compression damping valve of the second piston to flow the oil, and pushes and opens these soft expansion and compression damping valves. Due to the flow resistance of the oil when flowing, the external vibration applied to the vibrating body is effectively attenuated by generating an extension-side damping force and a compression-side damping force having good rising valve characteristics.

On the other hand, when the edge of the first piston moves to the position of the reduced diameter portion in the cylinder, the outer peripheral surface of the first piston slides on the inner wall surface of the cylinder and the bypass oil passage Close.

However, the interruption of the bypass oil passage by the first piston is achieved by a function of compensating for the excess or deficiency of oil at the bottom orifice due to the expansion / contraction operation of the position-dependent damper and the oil pressure in the lower hydraulic oil chamber during the compression operation. It has no effect on the securing function.

Therefore, during the extension operation of the position-dependent damper at this position, the hard extension damping valve of the first piston is connected in series with the soft extension damping valve of the second piston. The oil in the upper hydraulic oil chamber is pushed out and pushed out to the lower hydraulic oil chamber, and the hard and soft expansion damping valves are pushed open to generate the expansion damping force of the valve characteristic by the flow resistance of the flowing oil.

Similarly, even during the compression operation, together with the soft pressure-side damping valve in the second piston,
The hydraulic pressure damping valve of the first piston is also pushed in series and opened to push out the oil in the lower hydraulic oil chamber to the upper hydraulic oil chamber. Generates the compression damping force of the valve characteristics.

Thus, the position-dependent damper covers the entire displacement from the static balance position to the extension side and the compression side while automatically switching the damping force between high and low during the operation to the extension side. By maintaining the expansion and compression damping force in valve characteristics, the initial damping force rises during expansion and contraction operations and the damping force during expansion and contraction operations in the low-speed range can be increased to create a position-dependent damper with even better damping performance. it can.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a position-dependent damper according to the present invention will be described below.

In FIG. 1, a position-dependent damper 1 has a cylinder 2 and an outer shell 3 arranged around the cylinder 2. The upper end openings of the cylinder 2 and the outer shell 3 are formed by a bearing 4 and a seal case. 5 and sealed by a seal 6.

Similarly, the lower end openings of the cylinder 2 and the outer shell 3 are sealed by a lid 7 and a bottom cap 8, respectively, and the lid 7 is pressed against the inner surface of the bottom cap 8 on the outer shell 3 side. By centering, the cylinder 2 is held concentric with the outer shell 3.

At the upper end of the cylinder 2, a reduced-diameter portion 9 having a predetermined length is formed by narrowing the side wall inward, and the side wall portion slightly higher than the lid 7 in the cylinder 2 is formed. The bottom orifice 10 through the cylinder 2
Is provided.

As a result, the outer shell 3 partitions the reservoir chamber R between the outer shell 3 and the cylinder 2, and the reservoir chamber R is connected to the cylinder 2 through the bottom orifice 10.
It will lead to the lower part inside.

The piston rod 1 is provided inside the cylinder 2.
1 and fitted on the outer peripheral surface thereof with piston seals 12 and 13
The first piston 14 and the second piston 15 having the above are arranged vertically and inserted.

Further, in conjunction with this, the second piston 15
A guide member 17, which also has a seal 16 on the outer peripheral surface, is inserted below the lower surface of the second piston 15 by a spring 18 interposed between the guide member 17 and the lid 7 of the cylinder 2. They are fitted and arranged.

In this case, the outer diameter of the first piston 14 and the outer diameter of the second piston 15 are made to be large enough to fit the reduced diameter portion 9 formed on the upper end side of the cylinder 2. Only when the first and second pistons 14, 15 operate from the static equilibrium position X of FIG. 1 to face the inner wall surface excluding the reduced diameter portion 9, the cylinder 2 and the first and second The operation is performed with a clearance secured between the pistons 14 and 15.

On the other hand, the guide member 17 is formed such that the outer diameter thereof is adapted to the inner wall surface of the cylinder 2 excluding the reduced diameter portion 9, and the spring is in sliding contact with the inner wall surface of the cylinder 2 only in this range. By the restoring force of 18, the second piston 1
5 and operates following the fitting, and the inside of the cylinder 2 is extended by the seal 16 interposed on the outer peripheral surface to the upper hydraulic oil chamber U on the extension side.
And a lower hydraulic oil chamber L on the compression side.

The first and second pistons 14, 15
The piston rod 11 extending upward from the cylinder 2 and the bearing 4 for closing the upper ends of the outer shell 3 and the seal 6 housed in the seal case 5 protrudes to the outside through the upper end of the piston rod 11 and the outer shell 3. Dependent damper 1 through bottom cap 8 closing the lower end of
Is mounted between the two vibrating members.

On the other hand, the first piston 14 has an expansion side port 19 and a compression side port 20 penetrating in the axial direction, and the lower end of the expansion side port 19 and the upper end of the compression side port 20 are respectively connected to the lower hydraulic oil chamber L. It is closed by a hard pressure side damping valve 22 which is the same as the hard extension side damping valve 21 which opens toward the upper hydraulic oil chamber U.

Similarly, the second piston 15 also has an expansion port 23 and a compression port 24 that penetrate in the axial direction, and the lower end of the expansion port 23 and the upper end of the compression port 24 are connected to the lower hydraulic oil chamber. L and a soft pressure-side damping valve 26, which is open toward the upper hydraulic oil chamber U, and a soft pressure-side damping valve 26, respectively.

In this manner, the inner wall surface of the cylinder 2 and the outer peripheral surface of the first piston 14 are not changed until the first piston 14 expands and contracts in opposition to the reduced diameter portion 9 on the upper end side of the cylinder 2. The bypass oil passage 27 through which oil flows without pushing and opening the extension and compression damping valves 21 and 22 of the hardware is formed.

Next, the damping action of the position-dependent damper 1 configured as described above during the expansion and contraction operation will be described.

Now, assuming that the position-dependent damper 1 starts expanding and contracting with the external vibration applied to the vibrating body from the static balancing position X in FIG. 1, the first and second pistons 14,
15, the guide member 17 is fitted to the second piston 15 by the restoring force of the spring 18 and the cylinder 2
The inner wall surface of the cylinder is slid in contact with the cylinder 2 so as to maintain an oil-tight state.

Thus, in the initial stage of the expansion and contraction operation of the position-dependent damper 1 and during the expansion and contraction operation in the low speed range, the cylinder 2 and the cylinder 2 are not connected until the upper end edge of the first piston 14 reaches the reduced diameter portion 9 of the cylinder 2. First and second pistons 14,
The upper hydraulic oil chamber U on the extension side and the lower hydraulic oil chamber L on the compression side are intended to communicate with each other by securing a gap between the guide member 17 and the second piston 15. Are stopped by moving.

As a result, during the extension operation during this time, while the bypass oil passage 27 is secured, the first piston 14 is bypassed and the soft extension damping from the extension port 23 of the second piston 15 is performed. The valve 25 is pushed open to allow the oil in the upper hydraulic oil chamber U to flow to the lower hydraulic oil chamber L.

During the compression operation, the oil pressure in the lower hydraulic oil chamber L is secured by the flow resistance when the oil is pushed out from the lower hydraulic oil chamber L through the bottom orifice 10 to the reservoir chamber R. While pushing and opening the soft pressure-side damping valve 26 through the pressure-side port 24 of the second piston 15, oil flows from here into the upper hydraulic oil chamber U through the bypass oil passage 27 between the cylinder 2 and the first piston 14. Shed.

The shortage and surplus of oil in the cylinder 2 caused by the retraction (during the extension operation) and the intrusion (during the compression operation) of the piston rod 11 accompanying the extension and compression operations are reduced by the lower hydraulic oil chamber L Compensation is made by exchanging oil from the bottom orifice 10 with the reservoir chamber R.

Thus, the position-dependent damper 1 pushes and opens the soft expansion damping valve 25 or the soft compression damping valve 26 of the second piston 15 to allow oil to flow therethrough. Due to the flow resistance of the oil when it is pushed and opened to flow, the expansion side damping force and the compression side damping force of the valve characteristics with good rise are generated, and the external vibration applied to the vibrating body is effectively attenuated.

On the other hand, when the upper edge of the first piston 14 moves to the position of the reduced diameter portion 9 in the cylinder 2, the piston seal 12 provided on the outer peripheral surface of the first piston 14 The bypass oil passage 27 is closed by sliding contact with the inner wall surface.

Subsequently, the guide member 17 is further prevented from following by the reduced diameter portion 9 to open a gap between the cylinder 2 and the second piston 15, but before that, the second piston The piston seal 13 provided on the outer peripheral surface of the sliding member 15 slides on the inner wall surface of the reduced diameter portion 9 to keep the gap closed.

However, the guide member 17 is locked by the reduced diameter portion 9 and the first and second pistons 1
The sliding contact between 4 and 15 has no function for compensating the excess or deficiency of oil in the bottom orifice 10 due to the expansion and contraction of the position-dependent damper 1 and for ensuring the oil pressure in the lower hydraulic oil chamber L during the compression operation. Has no effect.

Therefore, during the extension operation of the position-dependent damper 1 at this position, the hard extension damping valve 21 is pushed and opened through the extension port 19 of the first piston 14, and then the extension of the second piston 15 is performed. The soft extension damping valve 25 is also pushed and opened through the side port 23 to push out the oil in the upper working oil chamber U to the lower working oil chamber L, and the hard and soft extension damping valves 21 and 25 are pushed and opened. The flow resistance of the flowing oil generates the extension side damping force of the valve characteristics.

During the compression operation, the soft compression damping valve 26 is pushed open through the compression port 24 of the second piston 15, and then the hard compression damping valve 22 is compressed through the compression port 20 of the first piston 14. To push out the oil in the lower hydraulic oil chamber L to the upper hydraulic oil chamber U.
A pressure-side damping force having valve characteristics is generated by the flow resistance of the oil that flows by pushing and opening the valves 6 and 22.

As described above, the position-dependent damper 1
As shown in FIG. 3, the damping force is automatically switched between high and low during the operation from the static balancing position X to the extension side, and the extension side over the entire operation to the extension side and the compression side. In addition, the compression damping force is maintained at the valve characteristic.

As described above, the arrangement of the first and second pistons 14 and 15 is reversed as in the position-dependent damper 1a of FIG. 2, and the guide member 17 and the spring 18 and the cylinder 2 By reversing the arrangement of the reduced diameter portion 9 as well, the damping force is automatically switched between high and low during the operation from the static balancing position X to the compression side as shown in FIG. It will be easily understood from the above description that the expansion-side and compression-side damping forces over the entire operation to the compression side can be maintained in the valve characteristics, without going into the trouble.

From these facts, by arranging the position-dependent damper 1 shown in FIG. 1 and the position-dependent damper 1a shown in FIG. 2 in parallel and using two, a static damper as shown in FIG. While the damping force is automatically switched between high and low in the middle of both the movement from the balance position X to the expansion side and the compression side, the expansion side and compression side damping forces over the entire operation to the expansion side and the compression side are determined by the valve characteristics. Needless to say, you can keep

In the above description, the embodiment of the present invention has been described by taking a double-cylinder type bottom orifice type position-dependent damper as an example. It is needless to say that the present invention can be applied to the position-dependent damper described above, a single cylinder type gas-filled position-dependent damper, or another type of position-dependent damper.

[0065]

As described above, according to the first aspect of the present invention, the damping force is automatically switched between high and low during the operation from the static balance position to the extension side, and at the same time as the extension side. The expansion-side and compression-side damping forces over the entire operation to the compression side can be maintained in the valve characteristics, and therefore, the rise of the initial damping force at the time of the expansion / contraction operation and the damping force at the time of the expansion / contraction operation in the low-speed range are also increased. Thus, a position-dependent damper having much better damping performance can be obtained.

According to the second aspect of the present invention, the damping force is automatically switched between high and low during the operation from the static balance position to the compression side, and the operation to the expansion side and the compression side is performed. With the valve characteristics, the extension and compression damping forces over the entire range are maintained in the valve characteristics, and the rise of the initial damping force during expansion and contraction and the damping force during expansion and contraction in the low-speed range are also increased, resulting in a position-dependent structure with even better damping performance. It can be a mold damper.

Further, according to the third aspect of the present invention, the damping force is automatically switched between high and low during the operation from the static balance position to both the extension side and the compression side, and the extension side and the compression side are switched. The damping force on the extension and compression sides over the entire operation to the valve is maintained in the valve characteristics, and the rise of the initial damping force during expansion and contraction and the damping force during expansion and contraction in the low-speed range are increased, resulting in even better damping performance. Can be obtained as the position-dependent damper.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment of a position-dependent damper according to the present invention.

FIG. 2 is a vertical sectional front view showing another embodiment of the position-dependent damper according to the present invention.

FIG. 3 is a characteristic diagram showing a relationship between a stroke and a damping force of the position-dependent damper in FIG.

FIG. 4 is a characteristic diagram showing a relationship between a stroke and a damping force of the position-dependent damper in FIG.

FIG. 5 is a characteristic diagram showing a relationship between a stroke and a damping force when two position-dependent dampers in FIGS. 1 and 2 are arranged in parallel.

FIG. 6 is a vertical sectional front view showing a position-dependent damper as a conventional example.

[Explanation of symbols]

 L Lower hydraulic oil chamber R Reservoir chamber U Upper hydraulic oil chamber X Static balance position 1, 1a Position-dependent damper 2 Cylinder 3 Outer shell 9 Reduced diameter portion 10 Bottom orifice 11 Piston rod 14 First piston 15 Second Piston 17 Guide member 18 Spring 21 Hard extension damping valve 22 Hard compression damping valve 25 Soft extension damping valve 26 Soft compression damping valve 27 Bypass oil passage

Claims (3)

[Claims] 1. A piston having a first piston having a hard extension damping valve and a hard compression damping valve, and a second piston having a soft extension damping valve and a soft compression damping valve. On the other hand, the first piston is located in the extension side and arranged in series, and the inner wall surface on the extension side of the cylinder is reduced to an inner diameter compatible with the outer diameters of the first and second pistons, and a reduced diameter portion. At the same time, a guide member that slides on the inner wall surface of the cylinder excluding the reduced diameter portion is arranged on the compression side of the second piston, and this guide member is brought into and out of contact with the second piston by a spring interposed between the cylinder and the cylinder. A position-dependent damper characterized by being fitted as possible. 2. A piston rod comprising: a first piston having a hard extension damping valve and a hard compression damping valve; and a second piston having a soft extension damping valve and a soft compression damping valve. On the other hand, the first piston is arranged in series with the piston located on the compression side, and the inner wall surface on the compression side of the cylinder is reduced to an inner diameter compatible with the outer diameters of the first and second pistons, and a reduced diameter portion is formed. At the same time, a guide member that slides on the inner wall surface of the cylinder excluding the reduced diameter portion is arranged on the extension side of the second piston, and this guide member is brought into contact with and separated from the second piston by a spring interposed between the cylinder and the cylinder. A position-dependent damper characterized by being fitted as possible. 3. The position-dependent damper according to claim 1, wherein
A position-dependent damper characterized in that two position-dependent dampers are arranged in parallel and used.