JP3087589B2 - Self-pumping shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber, and more particularly, to a self-pumping shock absorber.

[0002]

2. Description of the Related Art As one of shock absorbers for vehicles such as automobiles, for example, as described in Japanese Patent Application Laid-Open No. 59-159441, they are engaged with each other so as to be relatively reciprocable and cooperate with each other. A piston and a cylinder defining the chamber and the lower chamber, a damping force generating mechanism provided on the piston,
A pump having a low-pressure chamber, a high-pressure chamber communicating with the upper chamber, a pump chamber whose volume is increased or decreased by the relative movement of the piston and the cylinder, and a communication between the low-pressure chamber and the upper chamber when the shock absorber is extended beyond a predetermined amount. The pump has a communication control mechanism for connecting, the pump is reciprocally fitted to the pump cylinder member arranged in the rod portion of the piston, and is reciprocally fitted to the pump cylinder member, and is fixed to the cylinder at one end and cooperates with the pump cylinder member. A shock absorber that includes a pump rod that defines a pump chamber, a suction valve that allows oil to flow from the low-pressure chamber to the pump chamber, and a discharge valve that allows oil to flow from the pump chamber to the upper chamber. Oil is sucked into the pump chamber from the low-pressure chamber by the suction stroke corresponding to the extension stroke, and the pump chamber is sucked by the discharge stroke corresponding to the contraction stroke of the shock absorber. Shock absorber self-pumped configured to eject oil to the upper chamber is conventionally known.

According to the self-pumping type shock absorber, when the shock absorber expands and contracts repeatedly, the suction stroke and the discharge stroke of the pump are also repeated, whereby oil is supplied from the low-pressure chamber to the upper chamber and the lower chamber via the pump. When the shock absorber expands gradually and the amount of expansion of the shock absorber reaches a predetermined amount, the communication control mechanism prevents the shock absorber from expanding any more. However, the vehicle height can be automatically returned to the standard vehicle height in the process where the wheels repeatedly bounce and rebound as the vehicle travels.

[0004]

However, in a vehicle equipped with the above-described conventional self-pumping type shock absorber, when the wheels repeatedly bounce and rebound, the pump always operates and the vehicle height gradually increases. So
When a vehicle is transported by being fixed to a carrier car or a transport ship by a wire rope or a transport hook, the vehicle is vibrated by the vibration of the carrier car or the sway of the transport ship, and the shock absorber is greatly expanded and contracted. When the vehicle height increases, excessive stress acts on the wire rope and the like, which may be broken.

The present invention has been made in view of the above-mentioned problems in the conventional self-pumping type shock absorber, and a main object of the present invention is to invalidate the function of the pump if necessary. Accordingly, an object of the present invention is to prevent an increase in vehicle height when a vehicle is conveyed and a problem caused by the increase.

[0006]

According to the present invention, there is provided a piston and a cylinder which are relatively reciprocally fitted to each other and cooperate with each other to define a working fluid chamber; A damping force generating mechanism provided in the piston or the cylinder, a low-pressure chamber, a high-pressure chamber communicating with the working fluid chamber, and a working fluid from the low-pressure chamber to the high-pressure chamber due to relative movement of the piston and the cylinder. In a self-pumping type shock absorber having a supply pump, a bypass passage for communicating and connecting the low pressure chamber and the high pressure chamber and a second passage for disconnecting the bypass passage by being operated from outside the shock absorber. A self-pumping type shutter having a valve device that switches between a first position and a second position allowing communication of the bypass passage. An absorber (a configuration according to claim 1), or a piston and a cylinder which are fitted to each other so as to be relatively reciprocally movable and cooperate with each other to define a working fluid chamber, and a damping force generation provided on the piston or the cylinder A mechanism, a low-pressure chamber, a high-pressure chamber communicating with the working fluid chamber, and a pump for supplying a working fluid from the low-pressure chamber to the high-pressure chamber by a relative movement of the piston and the cylinder, wherein the pump is A pump cylinder hole provided in a rod portion of a piston, and a pump rod fixed at one end to the cylinder so as to reciprocally fit into the pump cylinder hole and cooperate with the pump cylinder hole to define a pump chamber. And a low-pressure passage means extending at least in the pump rod and communicating between the low-pressure chamber and the pump chamber. A bypass passage provided in the pump piston for communicating the low-pressure passage means with the working fluid chamber; and a bypass passage that is operated from outside a shock absorber to cut off communication of the bypass passage and the low-pressure passage. And a valve device that switches between a first position for allowing communication of said means and a second position for allowing communication of said bypass passage and cutting off communication of said low pressure passage means. This is achieved by a pumping type shock absorber.

[0007]

According to the first aspect of the present invention, the shock absorber has a bypass passage that connects the low-pressure chamber and the high-pressure chamber, and a first passage that disconnects the bypass passage by being operated from outside the shock absorber. And the valve device that switches to a second position that allows communication of the bypass passage, so that when the valve device is switched to the second position and the bypass passage is connected, the shock absorber becomes large. Even if the pump is expanded or contracted, the working fluid supplied to the high-pressure chamber by the pump returns to the low-pressure chamber via the bypass passage, and is in a state equivalent to a state where the pump does not perform the original pumping action.

Therefore, when the vehicle is conveyed, the valve device is switched to the second position and communicated with the bypass passage, whereby the vehicle is vibrated by the vibration of the carrier car or the sway of the transport ship, and the shock absorber is shocked. Does not increase the amount and pressure of the working fluid in the working fluid chamber, thereby causing the shock absorber to gradually expand and the vehicle height to gradually increase, and due to this, excessive stress on the wire rope etc. Is reliably prevented from acting.

According to the second aspect of the present invention, the shock absorber is provided in the pump rod and connects the low-pressure passage means to the working fluid chamber. The bypass passage is formed by operating the shock absorber from outside the shock absorber. The valve device switches between a first position for blocking communication and allowing communication of the low-pressure passage means and a second position for allowing communication of the bypass passage and blocking communication of the low-pressure passage means. If the valve device is switched to the second position and the bypass passage is communicated and the communication of the low-pressure passage means is cut off, the pump may draw the working fluid from the low-pressure chamber even if the shock absorber is greatly expanded and contracted. The working fluid sucked from the working fluid chamber and supplied to the high pressure chamber by the pump returns to the low pressure passage means via the working fluid chamber and the bypass passage, and the pump is Not carried out of the pumping action.

Therefore, when the vehicle is transported by being fixed to a carrier car or a transport ship by a wire rope or the like, the valve device is switched to the second position so as to communicate with the bypass passage and to connect the low pressure passage means. By interrupting the communication, even if the vehicle is vibrated by the vibration of the carrier car or the sway of the transport ship and the shock absorber is greatly expanded and contracted, the amount and pressure of the working fluid in the working fluid chamber does not increase,
As a result, the shock absorber is gradually extended and the vehicle height is gradually increased, and the excessive stress acting on the wire rope or the like due to this is reliably prevented.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 1 is a longitudinal sectional view showing a first embodiment of a self-pumping shock absorber according to the present invention, which is configured to perform a pumping discharge stroke in a contraction stroke.
FIG. 2 is an enlarged partial longitudinal sectional view showing the suction valve of the first embodiment and its vicinity, FIG. 3 is an enlarged partial longitudinal sectional view showing the discharge valve of the first embodiment and its vicinity, and FIG. It is an expansion partial longitudinal section showing the valve device of an example, and its neighborhood.

In these figures, reference numeral 10 denotes a cylinder. The cylinder 10 includes an inner cylinder 14 and an outer cylinder 16 which extend concentrically along an axis 12. The upper end of the outer cylinder 16 is closed by an end cap 16A integral therewith, and the end cap 18 is fixed to the lower end of the outer cylinder 16. The inner cylinder 14 has a support member 20 at the upper part.
And is fixed to the outer cylinder 16 at the lower end by an end cap 18 and seal caps 19A and 19B.

The support member 20 cooperates with a partition member 21 fixed to the lower end thereof and the outer cylinder 16 to define an annular low-pressure chamber 22.
And an oil 26 as a working fluid. A substantially cylindrical diaphragm 28 is arranged below the partition member 21 in an annular space between the inner cylinder 14 and the outer cylinder 16. The diaphragm 28 is fixed to the partition member 21 at the upper end and the end cap 1 at the lower end.
8, thereby defining a gas chamber 30 in which high-pressure gas is sealed radially outward and defining a high-pressure chamber 32 in which high-pressure oil 26 is sealed radially inward.

A piston 34 is arranged in the inner cylinder 14 so as to be able to reciprocate along the axis 12. The piston 34 has a piston rod 36 extending along the axis 12.
And a piston body 3 fixed to the upper end of the piston rod
8 The piston body 38 is provided with a damping force generating mechanism 40 for the extension stroke and a damping force generating mechanism 42 for the contraction stroke, which are well known per se. The piston rod 36 has a hollow hole 44 extending along the axis 12, and a pump cylinder member 46 extending along the axis 12 is fixedly disposed in the hollow hole 44.

A pump rod 48 extending along the axis 12 is fitted to the pump cylinder member 46 so as to be able to reciprocate relative to the pump cylinder member. Outer cylinder 1
6 and cooperates with a pump cylinder member to define a pump chamber 50. The piston 34 is the inner cylinder 1
The upper chamber 52 as a working fluid chamber is defined in cooperation with the spacer washer 49, the inner cylinder 14, and the pump rod 48 disposed between the inner cylinder 14 and the seal member 19B. It cooperates to define a lower chamber 54 as a working fluid chamber. The upper end of the upper chamber 52 is connected to the upper end of a high-pressure passage 55 defined between the inner cylinder 14 and the support member 20 and the partition member 21.

The pump rod 48 is provided with a low-pressure passage 56 extending along the axis 12, and the upper end of the low-pressure passage 56 is an intermediate portion defined between the upper end of the support member 20 and the end cap 16A. A chamber 60 and a conduit 60 fixed to the support member 20 are in communication with the lower portion of the low-pressure chamber 22. At the center in the longitudinal direction of the pump rod 48, a communication hole 62 is provided at the inner end thereof, which communicates with the low-pressure passage 56, and which is open at the outer end thereof on the outer surface of the pump rod and extends radially. In particular, in the illustrated embodiment, the lower portion of the pump rod 48 is tapered, so that the clearance between the pump rod and the pump cylinder member 46 is set to gradually increase as the vehicle height increases. Have been.

As shown in detail in FIG. 2, a suction valve 64 is provided at the lower end of the pump rod 48. The suction valve 64 has a substantially plate-shaped valve element 66, a substantially cup-shaped support member 68 fixed at the upper end to the lower end of the pump rod 48, and a spring between the valve element 66 and the support member 68. And a compression coil spring 70 which biases the valve element to the illustrated closed position where it abuts the lower end of the pump rod 48. The support member 68 is provided with a communication hole 72 such as a slit or a hole for connecting the inside of the support member and the pump chamber 50 for communication. The suction valve 64 allows the flow of oil from the low-pressure passage 56 toward the pump chamber 50, but functions as a check valve that prevents the flow of oil from the pump chamber toward the low-pressure passage.

As shown in detail in FIG. 3, a cup-shaped support member 76 is fixed to the lower end of the pump cylinder member 46 by a ring 74, and the support member 76 slides along the axis 12. It is fitted into the hollow hole 44 as much as possible. A discharge valve 78 is provided inside the support member 76 and below the pump cylinder member 46. The discharge valve 78 includes a substantially plate-shaped valve element 80, the valve element 80 and the support member 76.
And a compression coil spring 82 resiliently biased to the illustrated closed position against which the valve element abuts the lower end of the pump cylinder member 46. A compression coil spring 84 and a shim 8 are provided between the support member 76 and the bottom wall of the hollow hole 44.
6 are arranged, whereby the pump cylinder member 4
6 is urged upward in the figure via a support member, and is positioned by being pressed against a lock nut 87 fixed to the upper end of the piston rod 36.

The inner surface of the cylindrical portion of the support member 76 is provided with a plurality of slits 88 extending in the longitudinal direction. Outer peripheral surface of pump cylinder member 46 or pump rod 48
A plurality of grooves extending in the longitudinal direction are provided on the inner peripheral surface of the, and a plurality of communication passages 90 for communicating and connecting the slit 88 and the upper chamber 52 are defined by these grooves. The discharge valve 78 allows the flow of oil from the pump chamber 50 toward the communication passage 90, but functions as a check valve that prevents the flow of oil from the communication passage toward the pump chamber.

As shown in detail in FIG. 4, a bypass passage 92 for connecting the low pressure chamber 22 and the high pressure chamber 32 is formed in the partition wall member 21.
A valve device 94 is provided in the middle. In the illustrated embodiment, the valve device 94 is a needle valve screwed into the outer cylinder 16 and the partition member 21, and its knob 94.
By rotating the valve device at A in the longitudinal direction, the valve device is switched between a first position for interrupting the communication of the bypass passage 92 and a second position for permitting the communication of the bypass passage as shown in the figure. And is normally set to the first position. Knob 94A and outer cylinder 1
6, a seal ring 96 is interposed around the valve device 94.

Further, as shown in FIG. 1, a connecting member 100 is integrally provided at the lower end of the piston rod 36, and although not shown in the figure, between the connecting member 100 and the seal cap 19A. Has dust boots installed. Also, the end cap 1 at the upper end of the outer cylinder 16
A connecting member 102 is integrally fixed to 6A, and the shock absorber is connected to the vehicle body via a rubber bush (not shown) by the connecting member 102, and is not shown by the connecting member 100. It is connected to a suspension member such as a suspension arm via a rubber bush.

As understood from the above description, the high-pressure passage 55 defines high-pressure passage means for connecting and connecting the upper chamber 52 and the high-pressure chamber 32, and the conduit 60, the intermediate chamber 58, and the low-pressure passage 56 correspond to the low-pressure chamber 22. And the pump chamber 50 communicate with each other. The communication hole 62 cooperates with the upper end of the pump rod 48 when the piston 34 and the cylinder 10 are relatively displaced in the extending direction by a predetermined amount or more. When the vehicle height becomes equal to or higher than the standard vehicle height, a communication control means for communicating and connecting the upper chamber 52 and the low-pressure passage 56 is defined.

Further, the damping force generating mechanism 40 for the extension stroke and the damping force generating mechanism 42 for the contraction stroke are provided with a bouncing wheel,
A damping force generating means for generating a damping force in response to the rebound is defined, and members such as the pump cylinder member 46, the pump rod 48, the suction valve 64, and the discharge valve 78 are connected to the shock absorber by the bounce and rebound of the wheel. Is expanded and contracted to increase or decrease the volume of the pump chamber 50, thereby defining a pump 104 for pumping and supplying oil to the upper chamber 52 through the low-pressure passage means from the low-pressure chamber 22 as described later.

In the first embodiment constructed as described above, the volume of the upper chamber 52 increases when the piston 34 and the cylinder 10 move relative to each other during the extension stroke due to the rebound of the wheel (not shown). As the volume of the lower chamber 54 decreases, the oil in the lower chamber moves to the upper chamber via the piston body 38, and the damping force generating mechanism 40 generates a damping force in the extension stroke. Similarly, when the piston 34 and the cylinder 10 make a relative movement in the contraction stroke due to the bounce of the wheel, the volume of the upper chamber 52 decreases and the volume of the lower chamber 54 increases, so that the oil in the upper chamber passes through the piston main body 38 and lowers. It moves to the chamber, and the damping force generating mechanism 42 generates damping force in the contraction stroke.

In the extension stroke of the shock absorber, the volume of the pump chamber 50 increases and the pressure in the pump chamber decreases, so that the discharge valve 78 is closed and the suction valve 64 is opened. , A low pressure chamber 22, a conduit 60, an intermediate chamber 58, a low pressure passage 56, a suction valve 64, and a pump chamber 50.
The oil is sucked, whereby the suction stroke of the pump 104 is performed. Similarly, during the contraction stroke of the shock absorber, the volume of the pump chamber 50 is reduced and the pressure in the pump chamber is increased, so that the suction valve 64 is closed and the discharge valve 78 is opened, so that the pump Discharge valve 7 from chamber 50
8, the oil is discharged and supplied to the upper chamber 52 through the slit 88 and the communication path 90, whereby the discharge stroke of the pump 104 is performed.

When the suction stroke and the discharge stroke of the pump 104 are repeated, the amount and pressure of the oil in the upper chamber 52, the lower chamber 54, and the high-pressure chamber 32 increase, whereby the piston 34 and the cylinder 10 extend in the extending direction. When the communication hole 62 comes to a position above the upper end of the pump cylinder member 46, the upper chamber 52 is connected to the low-pressure passage 56 by the communication hole 62, and a part of the oil in the upper chamber 52 is removed. The piston 34 and the cylinder 10 are positioned with respect to each other such that the communication hole 62 is located at the upper end of the pump cylinder member 46 by discharging to the low pressure chamber 22. Therefore, even if the load of the vehicle fluctuates and the vehicle height fluctuates, the vehicle height is determined by the position of the communication hole 62 by the pumping action of the pump 104 and the positioning action of the communication hole 62 performed by the expansion and contraction of the shock absorber. Automatically returned to the standard vehicle height.

When the vehicle is further transported, the valve device 9
By switching the position 4 to the second position, the low-pressure chamber 22 and the high-pressure chamber 32 are set to be in a state of communication and connection. In such a state, even if the shock absorber is greatly expanded and contracted and the pump 104 is driven, the high-pressure chamber 32 is driven by the pump.
The oil supplied to the low-pressure chamber 2 through the bypass passage 92
2, the amount and pressure of oil in the upper chamber 52, the lower chamber 54, and the high-pressure chamber 32 do not increase, and thus the vehicle height does not increase.

Accordingly, in a situation where the vehicle is transported by being fixed to a carrier car or a transport ship by, for example, a wire rope or a transport hook, the vehicle is vibrated by the vibration of the carrier car or the like, and the shock absorber is expanded and contracted. In such a case, excessive stress is prevented from acting on the wire rope or the like due to the vehicle height being gradually increased by the pump action of the pump 104, and the low-pressure chamber 22 and the high-pressure chamber 32 are prevented. Since the pressures in the upper chamber 52 and the lower chamber 54 are equal to each other, the vehicle height is reduced to the minimum vehicle height, and the center of gravity of the vehicle body is set lower than normal, so that the stability of the vehicle during transportation is improved. I do.

FIG. 5 is an enlarged partial longitudinal sectional view showing a valve device of the second embodiment of the self-pumping type shock absorber according to the present invention which is configured to perform a pumping discharge stroke in a contraction stroke and its vicinity. 6 is an enlarged partial longitudinal sectional view showing a first position (A) and a second position (B) of the valve device of the second embodiment. In FIGS. 5 and 6, parts corresponding to the parts shown in FIG. 1 are denoted by the same reference numerals as in FIG.

In the second embodiment, a valve seat member 110 is fixed near the upper end of the pump rod 48.
The valve seat member 110 has a bypass passage 112 that connects the low pressure passage 56 and the upper chamber 52 in communication. The end cap 16A of the outer cylinder 16 supports a valve member 114 extending along the axis 12 by screwing, and the space between the end cap 16A and the valve member 114 is sealed by an O-ring 116. The valve member 114 has a knob 114 at the upper end.
A and a substantially spherical valve element 114B at the lower end. The inner end of the valve seat member 110 has a valve seat 118 for tightly receiving the valve element 114B, and the pump rod 48 has a valve seat 120 above the valve seat 118 for tightly receiving the valve element.

The valve seat member 110 and the valve member 114 cooperate with each other to define a valve device 122. The valve device 122 is moved along the axis 12 by rotating the knob 114A, so that the valve element 114B
When the valve element 114B is in close contact with the valve element 18 and separates from the valve seat 120, the communication with the bypass passage 112 is interrupted and the communication with the low-pressure passage 56 is allowed, as shown in FIG. The valve is switched to the second position shown in FIG. 6B in which the valve is in close contact with the valve seat 120 and is separated from the valve seat 118 to allow communication of the bypass passage 112 and cut off communication of the low-pressure passage 56. This is normally set to the first position.

The second embodiment is otherwise the same as the first embodiment. Therefore, in this embodiment also, the extension of the shock absorber through the conduit 60 from the low-pressure chamber 22 is performed. , Intermediate chamber 58, low pressure passage 56, suction valve (6
4) The suction stroke of the pump (104) is performed by the oil being sucked into the pump chamber (50) through the pump chamber (50). In the contraction stroke of the shock absorber, the discharge valve (78) and the communication passage are communicated from the pump chamber (50). The discharge stroke of the pump (104) is performed by discharging and supplying oil to the upper chamber 52 via (90).

As in the case of the first embodiment, the damping force generating mechanism (40) is used in the extension stroke of the shock absorber.
A damping force is generated by the damping force generating mechanism (42) during the contraction stroke of the shock absorber, and even if the load of the vehicle fluctuates and the height of the vehicle fluctuates, the damping force of the shock absorber is reduced. By the pumping action of the pump (104) and the positioning action of the communication hole (62) performed by the expansion and contraction, the vehicle height is automatically returned to the standard vehicle height determined by the position of the communication hole.

When the vehicle is further transported, the valve device 1
By switching the position 22 to the second position, the communication with the low-pressure passage 56 is cut off and the communication with the bypass passage 112 is allowed, so that the low-pressure passage 56 and the upper chamber 52 are set in a state of being connected to each other. In such a state, the pump (104) does not suck the oil from the low pressure chamber 22 but the upper chamber 52
The oil is sucked through the bypass passage 112 and the low-pressure passage 56, and the oil supplied to the upper chamber 52 by the pump (104) returns to the low-pressure passage 56 through the bypass passage 112. No oil is supplied to the vehicle and therefore the vehicle height does not increase.

Therefore, in a situation where the vehicle is conveyed by a carrier car or the like, and the vehicle is vibrated by the vibration of the carrier car or the like and the shock absorber is greatly expanded and contracted, the upper chamber 52 and the lower chamber ( Since the amount and pressure of the oil in 54) does not increase, it is possible to reliably prevent excessive stress from acting on the wire rope and the like due to the gradual increase in the vehicle height due to the pumping action of the pump (104). You.

In this case, when the valve device 122 is at the second position, the communication of the low-pressure passage 56 is cut off. Therefore, by rapidly switching the valve device 122 from the first position to the second position, the upper chamber is opened. A large amount of oil in the low pressure passage 5
6 to the low pressure chamber 22, whereby the pressure in the high pressure chamber 32, the upper chamber 52, and the lower chamber 54 decreases and becomes equal to the pressure in the low pressure chamber 22. As a result, it is possible to prevent the vehicle height from being greatly reduced.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to these embodiments, and various other embodiments may be included within the scope of the present invention. It will be clear to those skilled in the art that is possible.

For example, in the above two embodiments, the shock absorber is configured so that the discharge stroke of the pump is performed only during the contraction stroke. 6-27705
No. 8 (reference number AT-5027), as described in the specification and the drawings, the discharge stroke of the pump may be performed in both the extension stroke and the contraction stroke. The discharge stroke of the pump may be performed only in the elongation stroke as described in JP-A-6-245547.

[0040]

As is apparent from the above description, according to the configuration of the first aspect, when the valve device is switched to the second position and the bypass passage is communicated, the shock absorber is greatly expanded and contracted. Also, the working fluid supplied to the high-pressure chamber by the pump returns to the low-pressure chamber via the bypass passage, and becomes in a state equivalent to a state in which the pump does not perform the original pumping operation. Even if the shock absorber is greatly expanded and contracted due to vibration, the amount and pressure of the working fluid in the working fluid chamber does not increase,
As a result, it is possible to reliably prevent the shock absorber from gradually extending and the vehicle height from gradually increasing, and the resulting excessive stress acting on the wire rope and the like.

According to the second aspect of the present invention, when the valve device is switched to the second position and the bypass passage is communicated and the communication of the low pressure passage means is cut off, even if the shock absorber is greatly expanded and contracted, The pump does not suck the working fluid from the low pressure chamber but from the working fluid chamber, and the working fluid supplied to the high pressure chamber by the pump returns to the low pressure passage means via the working fluid chamber and the bypass passage. Since no pump action is performed, even in this configuration, even if the vehicle is vibrated by the vibration of the carrier car or the sway of the transport ship and the shock absorber is greatly expanded and contracted, the amount and pressure of the working fluid in the working fluid chamber increases. This ensures that the shock absorber is gradually extended and the vehicle height is gradually increased, and that excessive stress is not applied to the wire rope and the like due to this. It can be.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a self-pumping type shock absorber according to the present invention configured to perform a pumping discharge stroke in a contraction stroke.

FIG. 2 is an enlarged partial longitudinal sectional view showing the suction valve of the first embodiment and the vicinity thereof.

FIG. 3 is an enlarged partial longitudinal sectional view showing the discharge valve of the first embodiment and the vicinity thereof.

FIG. 4 is an enlarged partial longitudinal sectional view showing the valve device of the first embodiment and the vicinity thereof.

FIG. 5 is an enlarged partial longitudinal sectional view showing a valve device of a second embodiment of the self-pumping type shock absorber according to the present invention configured to perform a pumping discharge stroke in a contraction stroke and the vicinity thereof;

FIG. 6 is an enlarged partial longitudinal sectional view showing a first position (A) and a second position (B) of the valve device of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Cylinder 22 ... Low pressure chamber 32 ... High pressure chamber 34 ... Piston 40, 42 ... Damping force generating mechanism 46 ... Pump cylinder member 48 ... Pump rod 52 ... Upper chamber 54 ... Lower chamber 55 ... High pressure passage 56 ... Low pressure passage 62 ... Communication Hole 64 ... Suction valve 78 ... Discharge valve 92 ... Bypass passage 94 ... Valve device 104 ... Pump 112 ... Bypass passage 122 ... Valve device

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-235385 (JP, A) JP-A-59-159441 (JP, A) JP-B-47-49094 (JP, B1) JP-B-47- 49093 (JP, B1) JP 47-49095 (JP, B1) JP 46-59 (JP, B1) JP 42-11107 (JP, B1) Jiko 50-32693 (JP, Y1) (58) Field surveyed (Int.Cl. ⁷ , DB name) F16F 9/50 B60G 17/044

Claims (2)

(57) [Claims] 1. A piston and a cylinder which are fitted to each other so as to be relatively reciprocally movable and cooperate with each other to define a working fluid chamber, a damping force generating mechanism provided on the piston or the cylinder, and a low pressure chamber. A self-pumping shock absorber having a high-pressure chamber communicating with the working fluid chamber, and a pump for supplying a working fluid from the low-pressure chamber to the high-pressure chamber by the relative movement of the piston and the cylinder. A bypass passage for communicating between the chamber and the high-pressure chamber, a first position for interrupting the communication of the bypass passage by being operated from outside the shock absorber, and a second position for allowing the communication of the bypass passage. A self-pumping type shock absorber, comprising: 2. A piston and a cylinder which are relatively reciprocally fitted and cooperate with each other to define a working fluid chamber, a damping force generating mechanism provided on the piston or the cylinder, and a low pressure chamber. A high-pressure chamber communicating with the working fluid chamber, and a pump for supplying a working fluid from the low-pressure chamber to the high-pressure chamber by the relative movement of the piston and the cylinder, wherein the pump is connected to a rod portion of the piston. A pump cylinder hole provided, a pump rod fixed at one end to the cylinder, reciprocally fitted into the pump cylinder hole, and cooperating with the pump cylinder hole to define a pump chamber; the extending in the pump rod the low pressure chamber and said pumping chamber at a self-pumping shock absorber and a low pressure passage means for connecting communicating said Ponpuro' A bypass passage, which is provided in the first passage and communicates between the low-pressure passage means and the working fluid chamber; and a first passage that is operated from the outside of the shock absorber to cut off the communication of the bypass passage and allow the low-pressure passage means to communicate. And a valve device that switches between a second position and a second position that permits communication of the bypass passage and blocks communication of the low-pressure passage means.