JP5809536B2 - Vehicle shock absorber - Google Patents

Description

  The present invention relates to an improvement of a shock absorber for a vehicle.

  2. Description of the Related Art Conventionally, in a shock absorber for a vehicle, for example, a cylinder and a cylinder that is slidably inserted into the cylinder and divided into an extension side chamber and a pressure side chamber are assumed to have improved damping force generation response. A piston, a piston rod that is movably inserted into the cylinder and holds the piston in the center, an outer cylinder that is coupled to the lower end of the cylinder, and an inner cylinder that is accommodated in the outer cylinder and allows insertion on the lower end side of the piston rod Some include an inner cylinder and a free piston that is slidably inserted into both the outer cylinder and the inner cylinder to define a liquid chamber and an air chamber between the outer cylinder and the inner cylinder (for example, Patent Document 1).

  As a method for improving the damping force generation responsiveness of the vehicle shock absorber, increasing the pressure in the cylinder can be mentioned. Generally, a liquid has elasticity, and when a gas is dissolved in the liquid, the liquid column rigidity is low. When the liquid column rigidity is lowered, the liquid acts as a spring at the start of expansion and contraction of the vehicle shock absorber, and the rising of the damping force tends to be delayed in time. Therefore, when the pressure in the cylinder is increased to pressurize the liquid and the liquid column rigidity is increased, the damping force generation responsiveness is improved.

  However, when the cylinder internal pressure is set high with a single rod type shock absorber, the shock absorber is urged so as to always expand due to the cylinder internal pressure, so that the rod reaction force becomes large and the ride comfort in the vehicle is impaired. Result.

  On the other hand, in the conventional vehicle shock absorber described above, since the piston rod is a so-called double rod type shock absorber in which both the extension side chamber and the pressure side chamber are inserted, a single rod type shock absorber. As described above, even if the pressure in the air chamber is set high and the cylinder internal pressure is increased, the rod reaction force does not increase, so the liquid column rigidity is increased and the damping force generation response is improved. It is possible to achieve both improvement in damping force generation response and riding comfort without impairing comfort.

JP 2010-71413 A (FIG. 1)

  However, in the conventional vehicle shock absorber described above, particularly when it starts to expand or contract slowly or slowly, the piston speed is low, and the liquid passes through the orifice communicating the pressure side chamber and the liquid chamber without much resistance. Can do. That is, when the flow rate of the liquid passing through the orifice is small, the resistance given to the liquid flow by the orifice is small, so that the liquid can move back and forth between the liquid chamber and the pressure side chamber without resistance. Behaves as a compression chamber.

  When the apparent fluid chamber behaves as the pressure chamber, the apparent fluid volume in the pressure chamber is the sum of the fluid in the fluid chamber and the fluid in the fluid chamber. The liquid column rigidity is lower than the liquid column rigidity of the liquid only in the pressure side chamber.

  Therefore, in the conventional vehicle shock absorber, when the piston speed at the time of expansion and contraction is low, the liquid column rigidity of the compression side chamber is apparently reduced, so that the rise of the damping force is delayed in time. That is, the damping force generation responsiveness is deteriorated.

  In addition, if the damping force generation response of the vehicle shock absorber in the initial stage of expansion / contraction is poor, it is not possible to firmly suppress vehicle body posture changes such as during vehicle turning, braking, and acceleration from the beginning of the posture change. I feel uncomfortable.

  Therefore, the present invention was devised to improve the above-described problems, and its purpose is to improve the damping force generation response even when the piston speed during expansion and contraction is low. It is possible to provide a vehicle hydraulic shock absorber that can improve the ride comfort in a vehicle.

In order to solve the above-described problems, the problem solving means of the present invention includes an inner cylinder, an outer cylinder covering the inner cylinder, a piston slidably inserted into the inner cylinder, and an inner cylinder. An upper chamber and a lower chamber defined by the piston, a liquid chamber provided in the outer cylinder and below the lower chamber, a pressurizing means for pressurizing the liquid chamber, and a side of the outer cylinder A valve case provided on the lower chamber, a lower chamber communicating with the lower chamber, a partition wall communicating with the liquid chamber and a liquid chamber side chamber positioned below the lower chamber, and the partition A discharge passage provided in the partition wall for communicating the lower chamber side chamber and the liquid chamber side chamber; a piston passage provided in the piston for communicating the upper chamber and the lower chamber; and the inner series A suction passage that connects the upper chamber and the liquid chamber through a gap formed between the upper cylinder and the outer cylinder, and a discharge passage that opens and closes the discharge passage and opens the liquid from the lower chamber side chamber to the liquid chamber side chamber. A pressure-side damping valve that allows only the flow and provides resistance to the flow of the liquid; and opens and closes the piston passage to allow only the flow of liquid from the upper chamber to the lower chamber and provides resistance to the flow of the liquid An extension-side damping valve, a suction check valve that is provided in the middle of the suction passage and allows only the flow of liquid from the liquid chamber toward the upper chamber, and a suspension provided above the valve case of the outer cylinder A spring support is provided.

  In this vehicle shock absorber, since the liquid chamber and the pressurizing means for pressurizing the liquid chamber are provided, the rigidity of the liquid column in the extension side chamber and the pressure side chamber in the cylinder can be increased. In this vehicle shock absorber, the expansion side chamber compressed during the expansion stroke is not communicated with the liquid chamber through a path without any resistance, and the compression side chamber compressed during the contraction stroke is not provided. Since it communicates with the liquid chamber via the pressure side damping valve, it does not communicate with the liquid chamber via a path without any resistance, so the liquid chamber does not behave as a compression side chamber during both expansion and contraction strokes. The liquid column rigidity is not reduced.

  As described above, according to the vehicle shock absorber of the present invention, the damping force generation responsiveness can be improved even when the piston speed during expansion and contraction is low, and the riding comfort in the vehicle can also be improved. it can.

It is a longitudinal section of a shock absorber for vehicles in one embodiment.

  The present invention will be described below based on the embodiments shown in the drawings. As shown in FIG. 1, a vehicle shock absorber D according to an embodiment includes an inner cylinder 1, an outer cylinder 2 that covers the inner cylinder 1, and a piston 3 that is slidably inserted into the inner cylinder 1. The upper chamber R1 and the lower chamber R2 defined by the piston 3 in the inner cylinder 1, the liquid chamber L provided in the outer cylinder 2 and below the lower chamber R2, and the pressure applied to the liquid chamber L Pressure means P, a valve case 4 fixed to the side of the outer cylinder 2, a lower chamber side chamber 6 communicating with the valve case 4 to the lower chamber R2, and a liquid chamber side chamber 7 communicating with the liquid chamber L. A partition wall 5 partitioning, a discharge passage 8 provided in the partition wall 5 for communicating the lower chamber side chamber 6 and the liquid chamber side chamber 7, and a piston passage 9 provided for the piston 3 for communicating the upper chamber R1 and the lower chamber R2. And inner cylinder 1 and outer Only the flow of liquid from the lower chamber side chamber 6 to the liquid chamber side chamber 7 by opening and closing the suction passage 10 that connects the upper chamber R1 and the liquid chamber L through a gap formed between the cylinder 2 and the discharge chamber 8. And a compression side damping valve 11 that gives resistance to the flow of liquid and an extension side damping that opens and closes the piston passage 9 and allows only the flow of liquid from the upper chamber R1 to the lower chamber R2 and gives resistance to the flow of liquid. A valve 12, a suction check valve 13 provided in the middle of the suction passage 10 and allowing only a liquid flow from the liquid chamber L to the upper chamber R 1, and a suspension spring provided above the valve case 4 of the outer cylinder 2 The bearing 14 is configured to be interposed between a vehicle body and an axle (not shown) to exhibit a damping force during expansion and contraction to suppress vibration of the vehicle body.

  Hereinafter, each member will be described in detail. The inner cylinder 1 has a cylindrical shape and is accommodated in a cylindrical outer cylinder 2 longer than the inner cylinder 1. That is, the outer circumference of the inner cylinder 1 is covered by the outer cylinder 2, and in this case, an annular gap is formed between the inner cylinder 1 and the outer cylinder 2. Further, a piston 2 is slidably inserted into the inner cylinder 1, and the inner cylinder 1 is partitioned into an upper upper chamber R1 and a lower lower chamber R2 in FIG.

  The inner cylinder 1 has a surface treated on the inner periphery so that it can slide smoothly with the piston 3. Since the surface treatment of the inner cylinder 1 that is shorter than the outer cylinder 2 may be performed in this way, it is not necessary to perform the surface treatment of the long outer cylinder 2, so that the machining cost can be reduced, and the horizontal direction in the figure inputted from the piston 3 is reduced. Since the directional force is received by the inner cylinder 1, it is possible to use a light and relatively soft metal for the outer cylinder 2.

The piston 3 has an annular shape and is fixed in the middle of the piston rod 15. Specifically, the piston rod 15 is composed of an upper portion 15a and a lower portion 15b, and is integrally formed by screwing a screw shaft 15c provided at the lower end of the upper portion 15a into a screw hole 15d provided at the upper end of the lower portion 15b. The piston 3 is fixed between the upper portion 15a and the lower portion 15b. In the present embodiment, the vehicle shock absorber D is a so-called double rod type in which the piston 3 is fixed in the middle of the piston rod 15 and the upper end and the lower end of the piston rod 15 protrude from the inner cylinder 1 to the outside. However, the lower rod 15b of the piston rod 15 may be abolished, and the piston 3 may be fixed to the lower end of the upper portion 15a.

Returning, the piston 3 divides the inner cylinder 1 into an upper chamber R1 and a lower chamber R2, and includes a piston passage 9 that communicates the upper chamber R1 and the lower chamber R2. An extension side damping valve 12 formed of an annular leaf valve that opens and closes the lower end of the piston passage 9 is laminated on the lower end of the piston 3 in FIG. The extension side damping valve 12, flows piston 3 toward the lower chamber R2 is expanded from the upper chamber R1 which liquid is compressed the piston passage 9 during extended operation of moving into the Figure 1 upwardly relative the inner cylinder 1 At this time, the valve is opened to provide resistance to the flow of the liquid. On the contrary, at the time of the contraction operation, the piston passage 9 is closed to prevent the liquid flow from the lower chamber R2 toward the upper chamber R1.

  The extension-side damping valve 12 only allows a liquid flow from the upper chamber R1 to the lower chamber R2, and only needs to provide resistance to the liquid flow. Therefore, the expansion-side damping valve 12 may be a damping valve other than the leaf valve. It may be a combination of a check valve and a valve that allows two-way traffic, such as a choke or an orifice.

The outer cylinder 2 includes an upper small-diameter portion 2a provided with a small inner diameter on the upper side, a female screw portion 2b provided on the inner periphery of the opening in the upper part of FIG. 1 with respect to the upper small-diameter portion 2a, and a lower inner periphery having a small diameter. A lower small-diameter portion 2c provided as above, an annular convex portion 2d provided below the lower small-diameter portion 2c and projecting toward the inner peripheral side, and an inner peripheral screw portion 2e provided on the inner periphery of the annular convex portion 2d, , A male screw portion 2f provided on the outer periphery of the lower end, a perforation 2g that opens from the upper end step portion of the lower small diameter portion 2c and leads to the lower end step portion of the annular convex portion 2d, and a valve that is integrated so as to protrude sideways. A case 4 and an outer peripheral screw portion 2 h provided on the outer periphery and above the valve case 4 are provided.

Although not shown, a bracket capable of connecting the outer cylinder 2 to an axle (not shown) of the vehicle is screwed to the male screw portion 2 f . An annular suspension spring receiver 14 is screwed onto the outer peripheral screw portion 2h. The suspension spring receiver 14 supports a suspension spring that supports the vehicle body of the vehicle. Although not shown, the suspension spring receiver 14 cooperates with an upper suspension spring receiver connected to the upper end of the piston rod 15 to support the suspension spring. The spring is clamped. In this case, if the suspension spring 14 is within the axial installation range of the outer peripheral screw portion 2h, the axial mounting position relative to the outer cylinder 2 can be changed, but the suspension spring 14 is fixedly attached to the outer cylinder 2. It may be made like.

  The outer cylinder 2 is longer than the inner cylinder 1, and on the inner periphery of the upper small-diameter portion 2a described above, the piston rod 15 that is movably inserted into the cylinder 1 while holding the piston 3 is located on the upper side 15a in FIG. An annular rod guide 16 that pivotally supports is fitted. An annular rod guide 17 that pivotally supports the piston rod 15 on the lower portion 15b side in FIG. 1 is fitted to the lower small diameter portion 2c of the outer cylinder 2.

The rod guide 16 is provided at a lower portion and has a cylindrical socket portion 16a provided with a notch 16b, and is attached to the outer periphery and closely contacts the inner periphery of the upper small diameter portion 2a so as to be between the outer cylinder 2 and the rod guide 16. And a seal ring 16c for sealing. An annular suction check valve 13 is accommodated in the inner periphery of the socket portion 16a. An annular valve fixing member 18 is attached to the socket portion 16 a below the suction check valve 13. The valve fixing member 18 includes a port 18a penetrating it in the axial direction, and a tubular fitting portion 18b to be fitted in the socket portion 16a to the outer periphery, the lower side of the upper end opening end inner periphery of the inner cylinder 1 Fitted. As described above, when the valve fixing member 18 is fitted to the rod guide 16 and the inner cylinder 1, the outer periphery of the suction check valve 13 is sandwiched between the fitting portion 18 b of the valve fixing member 18 and the rod guide 16. Since the suction check valve 13 is fixed on the outer peripheral side as described above, bending of only the inner periphery is allowed. Further, in the state where the inner periphery is in close contact with the rod guide 16, the suction check valve 13 blocks communication between the notch 16b leading to the gap between the inner cylinder 1 and the outer cylinder 2 and the port 18a. The notch 16b communicates with the port 18a. The rod guide 17 is provided with a passage 17a that is annular and communicates from the upper end to the outer periphery in FIG.

  Further, an annular seal member 19 that seals between the rod guide 16 and the piston rod 15 and a spacer 39 are stacked above the rod guide 16, and the inner periphery of the lower small diameter portion 2 c of the outer cylinder 2 is laminated. An annular seal member 20 and a spacer 40 for sealing between the piston rod 15 and the outer cylinder 2 are accommodated between the annular protrusion 2d and the rod guide 17.

  And inside the outer cylinder 2, the spacer 40, the seal member 20, the rod guide 17, the inner cylinder 1, the valve fixing member 18, the suction check valve 13, the rod guide 16, the seal member 19 and the spacer 39 are accommodated in this order. When a nut 21 having a screw portion on the outer periphery is screwed onto the female screw portion 2b, each member housed in the outer cylinder 2 is sandwiched between the nut 21 and the annular convex portion 2d and fixed to the outer cylinder 2. . In this way, the seal members 19 and 20 and the seal ring 16c tightly seal the space between the piston rod 15 and the outer cylinder 2, and the upper chamber R1 and the lower chamber R2 are kept liquid-tight.

  In addition, a cylindrical rod insertion cylinder 22 is screwed to an inner peripheral screw portion 2 e provided on the inner periphery of the annular convex portion 2 d of the outer cylinder 2. The rod insertion cylinder 22 includes a cap 24 fitted to the inner periphery of the outer cylinder 2 at the lower end, and allows the lower portion 15b of the piston rod 15 to be inserted, so that the piston rod 15 can move up and down with respect to the outer cylinder 2. Yes.

  When the inner cylinder 1 is accommodated and fixed in the outer cylinder 2 as described above, the outer cylinder 2 has an annular shape between the inner surface between the upper small diameter portion 2a and the lower small diameter portion 2c and the outer surface of the inner cylinder 1. A gap is formed. The gap communicates with a liquid chamber L provided below the outer cylinder 2 by a perforation 2g that opens from the upper end step portion of the lower small diameter portion 2c of the outer cylinder 2 and communicates with the lower end step portion of the annular convex portion 2d. Therefore, in this case, the suction passage 10 that connects the upper chamber R1 and the liquid chamber L is formed by the gap formed between the inner cylinder 1 and the outer cylinder 2, and the port 18a, the notch 16b, and the perforation 2g. . The gap formed between the inner cylinder 1 and the outer cylinder 2 is not limited to the annular gap, and the shape is not limited.

  The liquid chamber L is defined by an annular free piston 23 slidably in contact with both the inner circumference below the annular projection 2d of the outer cylinder 2 and the outer circumference of the rod insertion cylinder 22 described above. The gap between the outer cylinder 2 and the rod insertion cylinder 22 is closed by an annular cap 24 provided at the lower end of the rod insertion cylinder 22, and the free piston 23 cooperates with the cap 24 to An air chamber G is defined between the cylinder 2 and the rod insertion cylinder 22. The pressure in the air chamber G presses the free piston 23 upward in FIG. 1 to pressurize the liquid chamber L, thereby forming a gas spring as urging means.

  That is, in the case of this embodiment, the pressurizing means P is a free piston 23 slidably inserted into the outer cylinder 2 and an urging means for urging the free piston 23 toward the liquid chamber L. And a gas spring. The cap 24 is provided with an airway 24a leading to the air chamber G, and the air chamber G is kept airtight by closing the airway 24a with a valve 24b. The pressure in the air chamber G can be adjusted by supplying gas to the air chamber G via the air passage 24a or discharging the gas from the air chamber G. In this vehicle shock absorber D, the gas chamber G and gas can constitute a gas spring to pressurize the liquid chamber L, and the pressure of the liquid chamber L is the above-described suction passage 10 and the discharge described later. Since it propagates through the passage 8 to the upper chamber R1 and the lower chamber R2, the inside of the cylinder 1 can be pressurized. In this embodiment, the liquid chamber L is pressurized with a gas spring. In addition to the gas spring, a spring other than the gas spring such as a coil spring may be used as the urging means. In addition, a metal bellows or diaphragm filled with gas in the liquid chamber L may be accommodated, and this may be used as a pressurizing means. When using a metal bellows, a spring other than a gas spring is used inside. May be provided. By making the urging means a gas spring that pressurizes the liquid chamber L with the gas enclosed in the air chamber G partitioned by the free piston 23, not only the urging force in the urging means can be easily adjusted, but also metal There is an advantage that the vehicle shock absorber D can be reduced in weight as compared with those using a coil spring or the like.

Subsequently, the valve casing 4 includes a hollow case body 30 provided in the outer cylinder 2, a lid 31 for closing an opening of the case body 30, the shaft member 32 is inserted into the case body 30 is screwed to the lid 31 In this case, it is integrated on the side of the outer cylinder 2 and is a single component. The valve case 4 may be configured as a separate part from the outer cylinder 2 and integrated with the outer cylinder 2.

  Specifically, the case main body 30 includes a hollow portion 30a that opens from the lower end, two passages 30b and 30c that open from the right end side in FIG. 1 to the hollow portion 30a, and a shaft that opens from the upper end to the hollow portion 30a. 30d of insertion holes. The passage 30b faces the opening end of the passage 17a on the outer periphery of the rod guide 17, and communicates with the lower chamber R2 through the passage 17a. The other passage 30 c communicates with the liquid chamber L.

  A partition wall 5 is fitted in the hollow portion 30 a of the case body 30. This partition wall 5 is in contact with the inner surface of the hollow portion 30a of the case body 30 so that the inside of the hollow portion 30a is divided into a lower chamber side chamber 6 on the upper side in FIG. 1 and a liquid chamber side chamber 7 on the lower side in FIG. It is partitioned. The lower chamber side chamber 6 communicates with the lower chamber R2 through the passage 30b and the passage 17a, and the liquid chamber side chamber 7 communicates with the liquid chamber L through the passage 30c.

  The partition wall 5 is annular, and includes a discharge passage 8 that communicates the lower chamber side chamber 6 and the liquid chamber side chamber 7, and a compensation passage 33 that similarly communicates the lower chamber side chamber 6 and the liquid chamber side chamber 7. The partition wall 5 is fixed to the case body 30 by being mounted on the outer periphery of the shaft member 32 inserted through the shaft insertion hole 30 d of the case body 30.

  Further, on the liquid chamber side chamber surface which is the lower surface in FIG. 1 of the partition wall 5, the pressure side damping valve 11 which is an annular leaf valve fixed to the outer periphery of the shaft member 32 and opening and closing the lower end opening in FIG. A compensation check valve 34, which is an annular leaf valve that is fixed to the outer periphery of the shaft member 32 and opens and closes the upper end opening of the compensation passage 33 in FIG. Are stacked. The pressure-side damping valve 11 may be a damping valve other than a leaf valve, as long as it allows only the flow of liquid from the lower chamber R2 to the liquid chamber L and provides resistance to the flow. Alternatively, a combination of a check valve and a valve that allows two-way traffic, such as a choke or an orifice, may be used. Further, the compression side damping valve 11 does not block the upper end opening in FIG. 1 of the compensation passage 33, and the compensation check valve 34 also does not block the lower end opening in FIG. 1 of the discharge passage 8. Yes.

  The shaft member 32 includes a shaft portion 32a, a flange 32b provided at the upper end of the shaft portion 32a in FIG. 1, and a screw portion 32c provided at the outer periphery of the lower end in FIG. 1, which is the tip of the shaft portion 32a. Is inserted into the shaft insertion hole 30 d in the case body 30.

  The annular spacer 41, the compensation check valve 34, the partition wall 5 and the compression side damping valve 11 are sequentially mounted on the outer periphery of the shaft portion 32a of the shaft member 32, and these lids 31 are screwed to the screw portion 32c, thereby hollowing them. Each member accommodated in the portion 30 a is fixed to the case body 30.

  The lid 31 includes a cylindrical portion 31a having a female screw on the inner periphery, a flange 31b provided on the outer periphery of the cylindrical portion 31a, and a seal ring 31c attached to the outer periphery of the flange 31b. When the cylindrical portion 31a is screwed to the screw portion 32c of the shaft member 32, the case main body 30, the annular spacer 41, the compensation check valve 34, the partition wall 5, and the compression side damping are formed by the cylindrical portion 31a and the flange 32b of the shaft member 32. The valve 11 can be clamped, and thereby each member is integrated. Further, the lid 31 seals the opening of the hollow portion 30a with a seal ring 31c, thereby keeping the hollow portion 30a liquid-tight.

  Thus, by providing the valve case 4 on the side of the outer cylinder 2 and providing the partition wall 5 and the pressure side damping valve 11 in the valve case 4, the pressure side damping valve 11 can be easily replaced, and the pressure side damping force. The outer cylinder 2 can be shortened by taking the partition wall 5 and the pressure side damping valve 11 out of the outer cylinder 2.

  In this embodiment, the hollow portion 30a opens downward with respect to the case body 30, but may be provided so as to open upward. Further, a cylindrical nut is integrated with the bottom of the hollow portion 30a, a shaft member is provided on the lid 31 side, and the compensation check valve 34, the partition wall 5 and the pressure side damping valve 11 are provided on the outer periphery of the shaft member of the lid 31. The hollow portion 30a is sealed by screwing the end of the shaft member of the lid 31 to the nut, and the compensation check valve 34, the partition wall 5 and the compression side damping valve 11 are accommodated and fixed in the hollow portion 30a. In this case as well, the opening of the hollow portion 30a can be directed upward.

  Next, the operation of the vehicle shock absorber D configured as described above will be described. First, the case where the piston 3 moves upward in FIG. 1 and the vehicle shock absorber D extends will be described. During this extension operation, the liquid in the upper chamber R1 that is compressed by the rise of the piston 3 pushes the extension-side damping valve 12 open and moves to the lower chamber R2. Therefore, when the vehicle shock absorber D is extended, the expansion side damping valve 12 is opened to give resistance to the flow of the liquid, so that the expansion side damping valve 12 generates an expansion side damping force. In this case, the vehicle shock absorber D is set to a double rod type, and the expansion side damping valve 12 is opened, the upper chamber R1 and the lower chamber R2 are communicated with each other, and the volume is reduced in the upper chamber R1. Since the volume of the lower chamber R2 increases, there is no liquid in and out of the liquid chamber L and the inner cylinder 1, but the vehicle shock absorber D is set to a single rod type, that is, the lower portion 17b of the piston rod 17 is When it is discarded, the compensation check valve 34 is opened and the insufficient liquid is supplied from the liquid chamber L to the lower chamber R2.

  Next, the case where the piston 3 moves downward in FIG. 1 and the vehicle shock absorber D contracts will be described. The liquid in the lower chamber R1 compressed by the lowering of the piston 3 during the contraction operation pushes and opens the compression side damping valve 11 and moves to the liquid chamber L. Therefore, when the vehicular shock absorber D is contracted, the compression side damping valve 11 is opened to give resistance to the flow of the liquid, so that the compression side damping valve 11 generates a compression side damping force. In addition, the liquid is supplied from the liquid chamber L to the upper chamber R1 to be expanded by opening the suction check valve 13.

  Although the vehicle shock absorber D operates as described above, the vehicle shock absorber D is provided with the liquid chamber L and the pressurizing means P for pressurizing the liquid chamber L. The liquid column rigidity in the chamber R1 and the lower chamber R2 can be increased.

  In the vehicle shock absorber D, the upper chamber R1 compressed during the expansion stroke is not communicated with the liquid chamber L through a path without any resistance, and is compressed during the contraction stroke. Since the lower chamber R2 is communicated with the liquid chamber L via the compression side damping valve 8, the lower chamber R2 is not communicated with the liquid chamber L through a path without any resistance. Therefore, the liquid column rigidity of the liquid is not lowered.

  Thus, according to the vehicle shock absorber D, not only the liquid column rigidity of the upper chamber R1 and the lower chamber R2 can be increased, but also the liquid chamber L does not behave as a compression side chamber during the expansion / contraction stroke. Since the column rigidity does not decrease, the damping force generation response can be improved even when the piston speed during expansion and contraction is low, and the riding comfort in the vehicle can also be improved. Therefore, in the vehicle shock absorber D, changes in the posture of the vehicle body such as when the vehicle is turning, braking, or accelerating can be firmly suppressed from the initial posture change.

  Further, in the vehicle shock absorber D, a partition wall 5 having a discharge passage 8 is provided in a valve case 4 provided on the side of the outer cylinder 2, and the discharge passage 8 is opened and closed to open the lower chamber side chamber 6. Since the pressure side damping valve 11 that allows only the flow of the liquid toward the liquid chamber side chamber 7 and gives resistance to the flow of the liquid is accommodated in the valve case 4, the outer periphery of the outer cylinder 2 is improved while improving the damping force generation response. The suspension spring receiver 14 for supporting the suspension spring S can be provided at the same time, and since the compression side damping valve 11 is installed outside the outer cylinder 2, the cylinder length is also shortened, so that the mounting property on the vehicle is sacrificed. There is no.

  In the vehicle shock absorber D, if the upper chamber R1 is the starting point, the flow of the liquid is a one-way flow that circulates from the upper chamber R1 to the upper chamber R1 via the lower chamber R2 and the liquid chamber L. The flow of the liquid is not reversed when the vehicle shock absorber D is switched. Thus, since the reversal of the flow of the liquid does not occur, it is possible to suppress a delay in the generation of the damping force when the vehicle shock absorber D is switched between expansion and contraction. Further, in this vehicle shock absorber D, the compensation passage 33 and the compensation check valve 34 can be eliminated. However, when these are provided, when the pressure decreases in the lower chamber R2, the liquid is reduced. Liquid can be quickly supplied from the chamber L to the lower chamber R2, and the pressure in the lower chamber R2 can be compensated to prevent vacuum.

Further, since the vehicular shock absorber D according to the present embodiment is of a double rod type, there is no liquid in and out of the liquid chamber L and the inner cylinder 1 during the expansion / contraction operation. There is no pressure fluctuation, which can contribute to further improvement in response to generation of damping force.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

  The hydraulic shock absorber for a vehicle according to the present invention can be used for a vibration damping application of a vehicle.

DESCRIPTION OF SYMBOLS 1 Inner cylinder 2 Outer cylinder 3 Piston 4 Valve case 5 Bulkhead 6 Lower chamber side chamber 7 Liquid chamber side chamber 8 Discharge passage 9 Piston passage 10 Suction passage 11 Pressure side damping valve 12 Extension side damping valve 13 Suction check valve 14 Suspension spring receiver 23 Free piston 33 Compensation passage 34 Compensation check valve L Fluid chamber P Pressurizing means R1 Upper chamber R2 Lower chamber

Claims (3)

An inner cylinder, an outer cylinder covering the inner cylinder, a piston slidably inserted into the inner cylinder, an upper chamber and a lower chamber defined by the piston in the inner cylinder, and the inner cylinder The liquid chamber provided below the lower chamber, the pressurizing means for pressurizing the liquid chamber, the valve case provided on the side of the outer cylinder, and the valve case communicated with the lower chamber. A partition wall that is communicated with the lower chamber side chamber and the liquid chamber and is divided into a liquid chamber side chamber located below the lower chamber side chamber, and the lower chamber side chamber and the liquid chamber side chamber that are provided in the partition wall and communicate with each other. Through a clearance formed between the inner cylinder and the outer cylinder, a discharge passage provided in the piston and communicating with the upper chamber and the lower chamber. Pressure-side damping that opens and closes the suction passage that connects the upper chamber and the liquid chamber, opens and closes the discharge passage, allows only the flow of liquid from the lower chamber side chamber to the liquid chamber side chamber, and provides resistance to the flow of the liquid A valve, an extension-side damping valve that opens and closes the piston passage and allows only the flow of liquid from the upper chamber toward the lower chamber and provides resistance to the flow of the liquid, and is provided in the middle of the suction passage. A vehicular shock absorber comprising: a suction check valve that allows only a flow of liquid from a liquid chamber toward the upper chamber; and a suspension spring receiver provided above the valve case of the outer cylinder.   The partition is provided with a compensation passage that communicates the lower chamber side chamber and the liquid chamber side chamber, and includes a compensation check valve that opens and closes the compensation passage and allows only the flow of liquid from the liquid chamber to the lower chamber. The vehicle shock absorber according to claim 1. The pressure means includes a free piston that is inserted slidably into the cylinder, according to claim 1 or claims the free piston, characterized in that it comprises a biasing means operable to urge into the fluid chamber Item 3. A vehicle shock absorber according to Item 2 .

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