JP5918587B2 - Shock absorber - Google Patents

Description

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

  Generally, the shock absorber is used for suppressing vibrations in transportation equipment such as automobiles and motorcycles, buildings, and the like.

  For example, Patent Document 1 discloses a vehicular shock absorber interposed between a vehicle body and a wheel of the vehicle, and the shock absorber includes a cylinder connected to one of the vehicle body side and the wheel side. The piston is slidably in contact with the inner peripheral surface of the cylinder, and the piston rod is erected at the center of the piston and connected to the other of the vehicle body side or the wheel side.

  The cylinder is partitioned by the piston into one chamber and the other chamber, and the one chamber and the other chamber are filled with working fluid. Further, the piston is formed with a flow path communicating with the one chamber and the other chamber, a window continuous with the flow path, and a valve seat surrounding the outer periphery of the window. Furthermore, the piston is laminated with an annular plate-like leaf valve whose inner peripheral side is fixed to the piston rod and whose outer peripheral side is seated on and off the seating surface of the piston.

  By providing the above configuration, when the shock absorber is moved in the axial direction in the cylinder, the piston rod pressurizes one chamber or the other chamber with the piston, and the working fluid deflects the outer peripheral side of the leaf valve. The shock absorber can generate a damping force due to the resistance of the leaf valve, that is, the deflection characteristic, because the shock absorber moves between the one chamber and the other chamber through the flow path.

JP 2011-94779 A

  Here, when the damping force is generated by utilizing the bending characteristic of the leaf valve as in the conventional shock absorber, the damping characteristic depends on the piston speed, and when the piston speed becomes maximum, the maximum damping force is Occur.

And when the said buffer is mounted in the vehicle which drive | works a continuous rough road, in order to make a wheel contact | abut on the ground, it is preferable that the damping force which generate | occur | produces in the expansion stroke of a buffer is small. However, if the damping force of the extension stroke is set to a small value, the vehicle may not be able to catch the large extension energy generated after a large compression input, for example, the vehicle climbs up and lands, and the vehicle may jump up. is there.

In addition, if the damping force of the extension stroke is set large in order to catch the large extension energy described above, the grounding property of the wheels is deteriorated, and in this case, the vehicle may be flipped up.

Therefore, in the above-described shock absorber, even if the damping force of the extension stroke is set to be small or large, it is impossible to continue stable high-speed running because of fear of vehicle damage.

Accordingly, an object of the present invention is to generate a large damping force temporarily in the expansion stroke immediately after a large compression input, and to quickly reduce the subsequent damping force to improve the wheel grounding property. It is to provide a possible shock absorber.

Means for solving the above-described problems include one chamber and the other chamber in which a working fluid is accommodated, a valve disk that divides the one chamber and the other chamber, and a flow path that communicates the one chamber and the other chamber. And a damping force generating means for imparting resistance to the working fluid passing through the flow path, and the working fluid moves between the one chamber and the other chamber during expansion and contraction, thereby generating a damping force. A bypass passage that bypasses the damping force generating means and communicates the one chamber and the other chamber, the bypass passage includes an on-off valve that communicates or blocks the bypass passage, And a check valve that allows movement of the working fluid from the chamber to the other chamber, and the time required for the on-off valve to open the bypass path in the extension stroke is larger as the stroke of the previous compression stroke is larger. longer It is when.

According to the present invention, it is possible to generate a large damping force temporarily in the expansion stroke immediately after a large compression input, and to quickly reduce the subsequent damping force to improve the grounding property of the wheel. Become.

It is the figure which showed in principle the piston part of the buffer which concerns on one embodiment of this invention. It is the longitudinal cross-sectional view which showed the piston part of the buffer which concerns on one embodiment of this invention. It is the figure which extracted the part containing the on-off valve and check valve of FIG. 2, and showed the state when the on-off valve moved largely to the one chamber side. It is the figure which extracted the part containing the on-off valve and check valve of FIG. 2, and showed the state when the on-off valve moved a little to the one chamber side. It is the figure which extracted the part containing the on-off valve and check valve of FIG. 2, and showed the state which the on-off valve and the check valve opened. It is a Lissajous waveform which showed the damping force with respect to the stroke of the buffer which concerns on one embodiment of this invention. It is the frequency characteristic graph which showed the damping force with respect to the frequency of the buffer which concerns on one embodiment of this invention.

  A shock absorber according to an embodiment of the present invention will be described below with reference to the drawings. The same reference numerals used throughout the several drawings indicate the same parts.

  In the present embodiment, the present invention is embodied in the piston portion of the shock absorber. As shown in FIG. 1, the shock absorber includes one chamber A and the other chamber B in which the working fluid is accommodated, a piston (valve disk) 1 that partitions the one chamber A and the other chamber B, and A flow path L that communicates the one chamber A and the other chamber B, and a damping force generating means V1 that provides resistance to the working fluid that passes through the flow path L are provided. By moving between the other chamber B, a damping force is generated. Further, the shock absorber includes a bypass M that bypasses the damping force generating means V1 and communicates the one chamber A and the other chamber B.

Further, the bypass passage M is provided with an on-off valve 2 that communicates and blocks the bypass passage M, and a check valve 3 that allows movement of the working fluid from the one chamber A to the other chamber B. When the shock absorber moves from the compression stroke to the expansion stroke , the on-off valve 2 shuts off the bypass M for a time depending on the stroke size of the immediately preceding compression stroke .

  Hereinafter, in detail, in the present embodiment, the shock absorber is formed in a hollow shape so that the on-off valve 2 is in sliding contact with the inner peripheral surface, and the on-off valve 2 is formed in the housing H. A bypass chamber m1 and a back pressure chamber n1 that are partitioned, and a back pressure channel n2 that communicates the back pressure chamber n1 and the other chamber B are provided.

  The bypass passage M communicates the bypass chamber m1, the first passage m2 and the first passage detour m4 that connect the bypass chamber m1 and the one chamber A, and the bypass chamber m1 and the other chamber B. And a second passage m3.

  Further, the on-off valve 2 moves in the housing H to one chamber side (left side in FIG. 1) and the other chamber side (right side in FIG. 1), and the opening / closing valve 2 By opening and closing the communication hole 60, the bypass path M is communicated or blocked. The on-off valve 2 is set so that it can move in the housing H to the one chamber side while the communication hole 2 is closed.

  Subsequently, the first passage m2 that communicates the bypass chamber m1 and the one chamber A is provided with damping force generating means V2 that provides resistance to the working fluid that passes through the first passage m2. For this reason, when the bypass path M is connected, resistance can be given to the working fluid passing through the bypass path M by the damping force generating means V2. Further, the speed at which the on-off valve 2 moves in the housing H can be limited by the resistance of the damping force generating means V2.

  Further, the first passage bypass m4 that communicates the bypass chamber m1 and the one chamber A in the same manner as the first passage m2 provides resistance to the working fluid that passes through the first passage bypass m4, and the first passage A variable throttle V4 for changing the flow rate of the working fluid passing through the detour m4 is provided. For this reason, the flow rate of the working fluid moving between the one chamber A and the bypass chamber m1 through the first passage m2 and the first passage bypass m4 is changed by the variable throttle V4, and the behavior of the on-off valve 2 is changed. In addition, the damping force of the shock absorber when the bypass M is in communication can be adjusted.

  Subsequently, the back pressure channel n2 that communicates the back pressure chamber n1 and the other chamber B is provided with a flow rate regulating means for regulating the flow rate of the working fluid that passes through the back pressure channel n2. Although various configurations such as a leaf valve and a throttle can be selected as the flow rate regulating means, in this embodiment, the flow rate regulating means includes a throttle V3. Since the flow restricting means (throttle V3) is provided, the speed at which the on-off valve 2 moves in the housing H is limited by the resistance of the restrictor V3 together with the damping force generating means V2 provided in the first passage m2. be able to.

  Further, the back pressure chamber n1 is provided with a spring 20, and when the on-off valve 2 moves to the other chamber side (right side in FIG. 1) from the neutral position, the on-off valve 2 is neutralized. Energize to return to position. The neutral position of the on-off valve 2 is preferably in the vicinity of the communication hole 60 and can be arbitrarily set. However, in this embodiment, as shown in FIG. It is set to be closed.

  Subsequently, the check valve 3 that permits the movement of the working fluid from the one chamber A to the other chamber B is provided in the second passage m3 in the present embodiment, and the other chamber is closed when the valve is closed. Even if the internal pressure of B increases, the valve does not open, but when the internal pressure of the bypass chamber m1 increases, the valve opens and communicates with the second passage m3.

  That is, by providing the above configuration, when the internal pressure in the other chamber B increases, the working fluid in the other chamber B passes through the back pressure flow path n2 and moves to the back pressure chamber n1. The on-off valve 2 moves to one chamber side (left side in FIG. 1) while pushing the working fluid in the bypass chamber m1 into the one chamber A, and closes the communication hole 60.

Next, when the internal pressure in the one chamber A increases, the working fluid in the one chamber A passes through the first passage m2 and the first passage bypass m4 (when the variable throttle V4 is open) and moves to the bypass chamber m1. The on-off valve 2 moves the hydraulic fluid in the back pressure chamber n1 to the other chamber side while extruded into other chamber B (right side in FIG. 1), opening the communication hole 60. Then, since the working fluid in the bypass chamber m1 opens the check valve 3, the working fluid in the one chamber A passes through the bypass passage M and moves to the other chamber B.

  In addition, the variable throttle V4 provided in the first passage detour m4, the on-off valve 2 for communicating or blocking the bypass passage M, and the check valve 3 provided in the second passage m3 are also provided in the first passage m2. Similar to the force generating means V2, resistance can be given to the working fluid passing through the bypass M, and the structure corresponds to a damping force generating means.

  Next, a specific configuration of the shock absorber will be described with reference to FIG. The shock absorber is a shock absorber for a vehicle interposed between a vehicle body and a wheel of the vehicle. The shock absorber for the vehicle is connected to the wheel side, and is connected to the vehicle body side in the cylinder S in the axial direction. The piston rod R is movably inserted, and is set upright.

  The one chamber A and the other chamber B are formed side by side in the axial direction in the cylinder S and filled with a working fluid, and the one chamber A is on the vehicle body side (upper side in FIG. 2). It arrange | positions and the said other chamber B is arrange | positioned at the wheel side (lower side in FIG. 2). Moreover, in this Embodiment, although the said working fluid consists of liquids, such as water and oil, it is not restricted to this, Various structures, such as another liquid and gas, are employable as said working fluid.

  Subsequently, the piston 1 that divides the one chamber A and the other chamber B is formed in an annular shape and is held on the outer periphery of a mounting portion r1 formed on the distal end side of the piston rod R. It slides in contact with the inner peripheral surface and moves in the axial direction in the cylinder S together with the piston rod R.

  In the present embodiment, the piston rod R has a tip projecting from the piston 1 to the other chamber B, and the other end extending through the one chamber A of the piston 1 and extending out of the cylinder S. It is set to the rod type. In order to compensate for the change in the cylinder volume corresponding to the volume of the piston rod that appears and disappears in the cylinder S, the shock absorber includes an air chamber that accommodates gas, although not shown.

  Returning, the piston 1 is formed with a flow path L communicating with the one chamber A and the other chamber B, and as a damping force generating means V1 for imparting resistance to the working fluid passing through the flow path L, A plurality of annular plate-like leaf valves 10 are stacked on the chamber side. These leaf valves 10 are fixed to the piston rod R on the inner peripheral side, and can be seated on and off from a seating surface 1 a formed on the piston 1 on the outer peripheral side. Further, the leaf valve 10 located closest to the piston among the leaf valves 10 is formed with a notch 10a. When the leaf valve 10 is closed, the notch 10a becomes an orifice.

  Further, in the present embodiment, the shock absorber is disposed on the one piston side of the piston 1, the sub piston case 5 covering the sub piston 4, and the other chamber side of the piston 1. The inner cylinder 6 and the outer cylinder 7 disposed on the outer periphery of the inner cylinder 6 are held together with the piston 1 on the outer periphery of the attachment portion r1 of the piston rod R.

  Further, the mounting portion r1 of the piston rod R is formed in a cylindrical shape, and a bypass chamber m1 is formed therein. Further, the piston rod R has a piston rod vertical hole r2 that is axially connected to one chamber side of the bypass chamber m1, and a piston rod first horizontal hole r3 that communicates the piston rod vertical hole r2 and the one chamber A. These constitute the first passage bypass m4 (FIG. 1), and the one chamber A communicates with the bypass chamber m1.

  The variable throttle V4 provided in the first passage detour m4 is inserted into the bush 8 that fits to the inner periphery of the piston rod vertical hole r2 and the tip end portion of the bush 8 is retractable from the opposite piston side. Needle 80, a control rod 81 provided on the back side of the needle 80, and a driving means (not shown) such as a motor and an adjuster for driving the needle 80 via the control rod 81. . For this reason, the working fluid that drives the needle 80 by the driving means to change the gap amount (throttle amount) between the tip of the needle 80 and the bush 8 and passes through the first passage detour m4 (FIG. 1). The flow rate can be adjusted.

  Returning, the sub-piston case 5 covering the sub-piston 4 is formed in a bottomed cylindrical shape, and a case chamber 50 formed inside is partitioned from the one chamber A by the sub-piston 4. The case chamber 50 communicates with the bypass chamber m1 through a piston rod second lateral hole r4 formed in the piston rod R.

  The sub-piston 4 is formed with a sub-piston passage hole 4a that communicates the case chamber 50 and the one chamber A. The sub-piston passage hole 4a, the case chamber 50, and the piston rod second lateral side are formed. The hole r4 constitutes the first passage m2 (FIG. 1), and the one chamber A communicates with the bypass chamber m1.

  The damping force adjusting means V2 provided in the first passage m2 includes a plurality of annular plate-like leaf valves 40 stacked on the case chamber side of the sub-piston 4, and these leaf valves 40 have an inner circumference. The side is fixed to the piston rod R, and the outer peripheral side is separable from a seat surface 4b formed on the sub piston 4. Furthermore, a notch 40a is formed in the leaf valve 40 located closest to the sub-piston side of the leaf valve 40. When the leaf valve 40 is closed, the notch 40a becomes an orifice.

  Subsequently, the inner cylinder 6 disposed on the other chamber side of the piston 1 is formed in a cylindrical shape, the inside is connected to the bypass chamber m1, and the housing H (FIG. 1) together with the mounting portion r1 of the piston rod R. ). Further, the inner cylinder 6 is connected to the outer periphery of the tip end portion of the mounting portion r1 of the piston rod R, and is connected to the anti-piston rod side of the connecting portion 6a so that the inner diameter is the inner diameter of the connecting portion 6a. A first body portion 6b formed slightly larger than the first body portion 6b, and a second body portion 6c connected to the anti-piston rod side of the first body portion 6b and having an inner diameter slightly larger than the first body portion 6b. And a holding portion 6d that is connected to the anti-piston rod side of the second body portion 6c and that the tip member 9 is screwed to the inner periphery, and the other chamber side opening of the inner cylinder 6 is the tip member 9. It is blocked by.

  Further, in the inner cylinder 6, the outer periphery protrudes from the holding portion side of the second body portion 6c to the holding portion 6d, and an annular flange portion 6e is formed. Furthermore, a communication hole 60 is formed at the first body side end of the second body 6c to be a second passage side opening of the bypass chamber m1. A cylindrical bearing 61 having an inner diameter equal to that of the first body portion 6b is fitted to the inner periphery of the second body portion 6c with respect to the holding portion side than the communication hole 60. The bearing 61 The on-off valve 2 is supported so as to be movable, and can move in the inner cylinder 6 in the axial direction.

  The on-off valve 2 includes a head portion 2a formed in a columnar shape and a cylindrical leg portion 2b connected to the outer peripheral portion on the tip member side of the head portion 2a. Further, the outer diameter of the on-off valve 2 coincides with the inner diameters of the first body 6b and the bearing 61, and the on-off valve 2 is formed on the bypass chamber m1 and the back member formed on the end member side of the on-off valve 2. The pressure chamber n1 is partitioned.

  And when the said on-off valve 2 moves to the one chamber side (upper side in FIG. 2) and the head part 2a is inserted in the 1st trunk | drum 6b, in order to close the said communicating hole 60, bypass path M (FIG. 1) is blocked. Even when the on-off valve 2 moves to the maximum extent in contact with the piston rod R (FIG. 3), the communication hole 60 is communicated with the back pressure chamber n1 because the leg side is supported by the bearing 61. The bypass path M (FIG. 1) can continue to be shut off. On the other hand, when the on-off valve 2 moves to the other chamber side (lower side in FIG. 2) and the head 2a comes out of the first body 6b, the communication hole 60 is opened, so that the bypass M (FIG. 1) Is communicated.

  The back pressure chamber n1 formed between the on-off valve 2 and the tip member 9 accommodates a spring 20 made of a coil spring, and the tip of the spring 20 is a leg portion of the on-off valve 2. It is movably inserted in 2b. The natural length of the spring 20 is set to be approximately equal to the distance from the end member side end surface of the head 2a of the on-off valve 2 in the neutral position to the on / off valve side end surface of the tip member 9. For this reason, the spring 20 can be urged to return the on-off valve 2 to the neutral position when the on-off valve 2 moves to the other chamber side (lower side in FIG. 2) from the neutral position. Further, when the on-off valve 2 moves to one chamber side (upper side in FIG. 2) from the neutral position, it moves without receiving the urging force of the spring 20, and even if it moves to the one chamber side to the maximum, the leg 2b. The tip of the spring 20 is set so as not to come out completely (FIG. 3).

  Further, a back pressure channel n 2 that communicates the back pressure chamber n 1 and the other chamber B is formed in the axial center portion of the tip member 9. Further, a throttle V3 that restricts the flow rate of the working fluid that passes through the back pressure channel n2 is also provided in the tip member 9.

  Subsequently, the outer cylinder 7 disposed on the outer periphery of the inner cylinder 6 is formed in a cylindrical shape, is formed in an annular shape, and is sandwiched between the piston 1 and the coupling portion 6 a of the inner cylinder 6. And a cylindrical main body portion 7b connected to the outer periphery of the lid portion 7a on the side opposite to the piston. A cylindrical passage 70 is formed between the main body portion 7 b and the inner cylinder 6.

  Further, in the outer cylinder 7, the outer periphery of the lid portion 7a projects outward, and a horizontal annular seating surface 7c is formed on the opposite piston side. On the other hand, the non-piston side end portion of the main body portion 7b is disposed on the upper side in FIG. 2 of the flange portion 6e of the inner cylinder 6. Further, the inner periphery of the end portion on the side opposite to the piston of the main body portion 7b protrudes inward and is a second lower portion in FIG. 2 than the communication hole 60 in the inner cylinder 6 through a seal (not shown) engaged with the inner periphery. It is in close contact with the outer periphery of the trunk portion 6c. An outer cylinder lateral hole 71 is formed at the piston side end of the main body 7b, and the outer cylinder lateral hole 71 and the cylindrical passage 70 constitute the second passage m3 (FIG. 1). The bypass chamber m1 and the other chamber B communicate with each other.

  The check valve 3 provided in the second passage m3 is formed in a cylindrical shape, and a valve head 30 slidably attached to the outer periphery of the main body portion 7b of the outer cylinder 7, and a flange portion of the inner cylinder 6 6e is provided with a biasing spring 31 that stands on 6e and biases the valve head 30 toward the piston (in the closing direction).

  In addition, a horizontal annular front end surface 30a is formed on the counter biasing spring side of the valve head 30, and a tapered surface that gradually increases in diameter toward the front end surface 30a is formed on the inner peripheral surface of the valve head 30. 30b is formed. For this reason, the check valve 3 opens and closes the second passage 3m (FIG. 1) by causing the tip end surface 30a to be separated from and seated on the seat surface 7c of the outer cylinder 7. Further, since the valve head 30 has the above shape, the check valve 3 does not open even when the internal pressure of the other chamber B increases when the check valve 3 is closed, but when the internal pressure of the bypass chamber m1 increases. So that the working fluid is allowed to move from one chamber side to the other chamber side.

By providing the above configuration, when the check valve 30 is closed and the bypass passage M is shut off, the other chamber B pressurized by the piston 1 in the compression stroke of the shock absorber in which the piston rod R enters the cylinder S. The working fluid passes through only the flow path L of the piston 1 and moves to the one chamber A. At this time, the working fluid passing through the flow path L can move to the one chamber A by bending the outer peripheral portion of the leaf valve 10 stacked on the piston 1. Therefore, as shown in FIG. 6, never damping force in the compression stroke becomes excessive be blocked bypass passage M.

Further, in the compression stroke of the shock absorber, the pressurized working fluid in the other chamber B passes through the back pressure channel n2 and flows into the back pressure chamber n1, so that the on-off valve 2 is pushed up and the communication hole 60 is closed. The bypass chamber m1 is pressurized. At this time, the leaf valve 40 stacked on the sub-piston 4 does not open, so that the working fluid in the bypass chamber m1 has a gap between the notch 40a (orifice) of the leaf valve 40 and the bush 8 and the tip of the needle 80. (Only when the variable throttle V4 is open) passes through and flows out into the one chamber A.

The amount of movement of the on-off valve 2 depends on the flow rate of the working fluid flowing into the back pressure chamber n1, and the on-off valve 2 moves toward the one chamber as the flow rate of the working fluid flowing into the back pressure chamber n1 increases (see FIG. 2). Further, the flow rate of the working fluid flowing into the back pressure chamber n1 depends on the size of the stroke of the shock absorber (hereinafter referred to as the pressure side stroke) in the compression stroke , and the larger the pressure side stroke, the more the fluid flows into the back pressure chamber n1. The flow rate of working fluid increases.

  For this reason, when there is a large compression input in the shock absorber and the pressure side stroke becomes large, as shown in FIG. 3, the on-off valve 2 moves to the one chamber side greatly exceeding the communication hole 60 while closing the communication hole 60. However, when the compression side stroke is reduced, the movement amount of the on-off valve 2 is also reduced accordingly (FIG. 4).

Next, the shock absorber is the compression stroke, the piston rod R moves the extension process exiting from the cylinder S, the working fluid in one chamber A which in the piston 1 has been pressurized, and the sub-piston hole 4a, the bushing 8 Through the gap between the needle 80 and the tip of the needle 80 (only when the variable throttle V4 is open) and flows into the bypass chamber m1. For this reason, the on-off valve 2 is pushed down by the working fluid flowing into the bypass chamber m1 to pressurize the back pressure chamber n1, and the working fluid in the back pressure chamber n1 passes through the back pressure channel n2 and flows out into the other chamber B. .

The pressurized working fluid in one chamber A passes through only the flow path L of the piston 1 and moves to the other chamber B until the on-off valve 2 is pushed down to open the communication hole 60. At this time, the leaf valve 10 of the piston 1 does not open. Therefore, the working fluid in the one chamber A moves only to the notch 10a (orifice) of the leaf valve 10 and moves to the other chamber B. For this reason, as indicated by f1 in FIG. 6, the damping force immediately after the transition from the compression stroke to the expansion stroke rapidly increases.

  When the upper end of the on-off valve 2 in FIG. 2 reaches the second body portion 6c of the inner cylinder 6 and the on-off valve 2 opens the communication hole 60, the working fluid in the bypass chamber m1 flows out into the cylindrical passage 70, The valve head 30 is pushed down against the urging force of the urging spring 31 to open the check valve 3 and move to the other chamber B.

That is, when the on-off valve 2 opens the communication hole 60, the check valve 3 opens and the bypass passage M (FIG. 1) communicates, so that the pressurized working fluid in the one chamber A flows into the flow path L and the bypass passage. It becomes possible to move to the other chamber B through M. At this time, the working fluid passing through the bypass passage M can move into the bypass chamber m1 by bending the outer peripheral portion of the leaf valve 40 stacked on the sub-piston 4. For this reason, as indicated by f2 in FIG. 6, the damping force (f1) rapidly increased immediately after the transition from the compression stroke to the expansion stroke is rapidly reduced.

In the following description, when the peak of the curve composed of f1 and f2 is the peak P1 of the on-off valve characteristic, the value of the peak P1 of the on-off valve characteristic increases as the time until the on-off valve 2 opens the communication hole 60 increases. growing. As shown in FIGS. 3 and 4, the opening / closing valve 2 does not advance by opening the communication hole 60 as the movement amount of the opening / closing valve 2 in the immediately preceding compression stroke increases, that is, as the immediately preceding pressure side stroke increases. Since the distance X that does not become longer, the time until the on-off valve 2 opens the communication hole 60 becomes longer.

That is, the value of the peak P1 of the on-off valve characteristic depends on the size of the previous pressure side stroke, and as indicated by the two-dot chain line p1 in FIG. 7, the value of the peak P1 increases as the previous pressure side stroke increases. Further, the value of the peak P2 (FIG. 6) of the damping force after the check valve 3 is opened in this extension stroke is independent of the magnitude of the immediately preceding compression side stroke, as indicated by the two-dot chain line p2 in FIG. It is constant and kept small.

Returning, the opening and closing valve 2 opens the communication hole 60, and when the shock absorber further shifts to the compression stroke from the expansion stroke in which the check valve 3 is open, the other chamber B is pressurized by the piston 1. However, until the check valve 3 is closed by the biasing force of the biasing spring 31, the internal pressure of the bypass chamber m1 becomes equal to the internal pressure of the other chamber B. For this reason, the on-off valve 2 is maintained in a state where the communication hole 60 is opened, and the bypass passage M (FIG. 1) is temporarily communicated even in the compression stroke . Thereby, as indicated by f3 in FIG. 6, the initial damping force of the compression stroke is temporarily reduced.

Further, when the stroke of the shock absorber is small and the shock absorber repeats the expansion stroke and the compression stroke at a short cycle, the on-off valve 2 moves up and down near the neutral position as shown in FIG. However, the time for closing the communication hole 60 is shortened. Furthermore, since the check valve 3 is maintained in a substantially open state with a delay in closing, the bypass path M is maintained in a substantially connected state regardless of the extension stroke or the compression stroke . Therefore, as shown in FIG. 7, not only the expansion stroke but also the damping force of the compression stroke is reduced on the high frequency side.

It should be noted that the size of the compression input for generating the above-mentioned on-off valve characteristic peak P1, the size of the pressure side stroke of the shock absorber, the on-off valve 2 is moved up and down near the neutral position, or the check valve 3 is substantially open. size and stroke for maintaining or, or cycle to repeat expansion and compression strokes, frequency, etc., not is limited as an absolute value, it can be set arbitrarily according to the specifications of the shock absorber It is.

  Returning to the shock absorber according to the present embodiment, as shown in FIG. 2, the oil lock piece 90 held on the outer periphery of the tip member 9 and the wheel S side end of the cylinder S are not shown. An oil lock case is provided, and the oil lock piece 90 can be fitted into the oil lock case and locked with oil when the shock absorber is compressed most. Thereby, the shock at the time of the most compression of a shock absorber can be absorbed.

Further, when the oil lock piece 90 is fitted in the oil lock case, the back pressure passage n 2 communicates with the oil lock case, since the oil in the lock case is made of a pressure higher than the other chamber B, the back pressure chamber n1 A larger amount of working fluid can be allowed to flow into the inside, and a large damping force can be generated in the immediately following extension stroke .

  Furthermore, the shock absorber according to the present embodiment is provided with a rebound support r5 that is held on the outer periphery of the piston rod R and protrudes to the outer peripheral side, on the opposite piston side of the sub-piston 4. Further, although not shown, a rebound cushion is attached to an annular rod guide that is attached to the opening on the vehicle body side of the cylinder S and pivotally supports the piston rod R. For this reason, the rebound cushion abuts against the rebound support r5 when the shock absorber is fully extended, and is elastically deformed to absorb the shock when the shock absorber is fully extended.

  Next, operational effects of the shock absorber according to the present embodiment will be described. The shock absorber according to the present embodiment includes one chamber A and the other chamber B in which the working fluid is accommodated, a piston (valve disk) 1 that partitions the one chamber A and the other chamber B, and the one chamber A and the other chamber. A flow path L that communicates with B, a damping force generation means V1 that provides resistance to the working fluid that passes through the flow path L, and a communication between the one chamber A and the other chamber B that bypasses the damping force generation means V1. And a bypass path M.

The bypass path M is provided with an on-off valve 2 that communicates and blocks the bypass path M, and a check valve 3 that allows movement of the working fluid from one chamber A to the other chamber B. cage, shock absorber shifting to the extension process from the compression stroke, the on-off valve 2, the time dependent on the magnitude of the compression stroke just before the stroke (compression side stroke), blocking the bypass passage M.

And, when the vehicle equipped with the shock absorber of the present embodiment travels on a continuous rough road, climbs up a bump, and lands, when the shock absorber has a large compression input, the shock side stroke of the shock absorber is large. Become. For this reason, the time during which the on-off valve 2 shuts off the bypass path M becomes longer in the extension stroke immediately after.

  While the on-off valve 2 closes the bypass path M, the working fluid passes only through the flow path L and moves from the one chamber A to the other chamber B, so that the shock absorber temporarily generates a large damping force. To do. For this reason, with this large damping force, it is possible to receive a large stretch energy generated after a large compression input and to suppress the vehicle from being flipped up.

Further, when the on-off valve 2 opens the bypass passage M, the working fluid passes through both the flow passage L and the bypass passage M and can move from the one chamber A to the other chamber M, so that a large damping force is generated in the extension stroke . It is possible to improve the grounding performance of the wheel by quickly reducing the damping force after the operation.

  In the present embodiment, the shock absorber is formed in a hollow shape so that the on-off valve 2 is in sliding contact with the inner peripheral surface, and a bypass chamber formed in the housing H and defined by the on-off valve 2. m1 and a back pressure chamber n1, and a back pressure flow path n2 that connects the back pressure chamber n1 and the other chamber B to each other.

  The bypass passage M includes the bypass chamber m1, a first passage m2 that communicates the bypass chamber m1 and the one chamber A, and a second passage m3 that communicates the bypass chamber m1 and the other chamber B. Configured.

  Further, the on-off valve 2 can open and close the communication hole 60 of the housing H which becomes the second passage side opening of the bypass chamber m1, and can move the inside of the housing H to the one chamber side while closing the communication hole 60. .

Therefore, in the compression stroke of the shock absorber, can be moved off valve 2 on one chamber side according to the flow rate of the working fluid flowing through the backpressure passage n2 from the other chamber B to the back pressure chamber n1 It becomes. The flow rate of the working fluid flowing into the back pressure chamber n1 depends on the magnitude of the immediately preceding pressure side stroke, and the time until the communication hole 60 is opened increases as the movement amount of the on-off valve 2 increases. Therefore, when the shock absorber moves to the expansion stroke , it is possible to easily make the time during which the on-off valve 2 blocks the bypass M depending on the stroke (pressure side stroke) of the immediately preceding compression stroke. .

In the present embodiment, the back pressure channel n 2 is provided with a throttle V3 serving as a flow rate regulating means for regulating the flow rate of the working fluid passing through the back pressure channel n 2 . For this reason, it is possible to adjust the moving speed of the on-off valve 2 to the other chamber side by setting the flow rate regulating means, and it is possible to arbitrarily set the time during which the on-off valve 2 blocks the bypass M. It becomes.

  In the present embodiment, the check valve 3 is provided in the second passage m3, and the valve head 30 that opens and closes the second passage m3 and the biasing spring 31 that biases the valve head 30 in the closing direction are provided. I have.

For this reason, check if the shock absorber has a short stroke and the shock absorber repeats the compression stroke and the expansion stroke in a short cycle, such as when a vehicle equipped with a shock absorber travels on a paved road. By utilizing the closing delay due to the inertial force of the valve 3, the bypass path M can be maintained in a substantially connected state. Therefore, the damping force of the shock absorber in the compression stroke and the extension stroke can be suppressed to be small, and the riding comfort of the vehicle can be improved.

Further, in the present embodiment, a spring 20 is provided for biasing the on-off valve 2 to return to the neutral position when the on-off valve 2 moves in the housing H from the neutral position to the other chamber side. Therefore, the on-off valve 2 is prevented from excessively moving in the other chamber side in the extension process, when going to the compression stroke from the extended stroke of the damper communication hole 60 is opened promptly neutral position off valve 2 It becomes possible to return to. Further, when it is desired to change the neutral position of the on-off valve 2, the spring 20 may be changed, and the neutral position of the on-off valve 2 can be easily set or changed.

  In the present embodiment, the first passage m2 is provided with damping force generating means V2 that provides resistance to the working fluid that passes through the first passage m2, and the bypass path M is provided with the damping force generating means. A first passage detour m4 that bypasses V2 and communicates the one chamber A and the bypass chamber m1 is provided. The first passage detour m4 is provided with a variable throttle V4 that changes the flow rate of the working fluid that passes through the first passage detour m4.

  For this reason, the behavior of the on-off valve 2 moving in the housing H can be arbitrarily changed by changing the flow rate of the working fluid passing through the first passage bypass m4 with the variable throttle V4.

  Although preferred embodiments of the present invention have been described in detail above, it should be understood that modifications, variations and changes may be made without departing from the scope of the claims.

  For example, in the above-described embodiment, the shock absorber is set upright, but may be set upside down. In this case, the check valve 3 does not have to include the biasing spring 31 because the valve head 30 moves to the piston side by its own weight and can be seated on the seat surface 7c.

  In the above embodiment, the present invention is embodied in the piston portion of the shock absorber. The reservoir compensates for the change in the cylinder volume corresponding to the volume of the piston rod in and out of the cylinder S, and the reservoir In the case of including a liquid reservoir chamber made of a working fluid stored in and a base member that partitions the liquid reservoir chamber and the other chamber B, the present invention may be embodied in the base member portion. In this case, the valve disk in the claims is the base member, the one chamber in the claims is the liquid reservoir chamber, and the other chamber in the claims is the other chamber B.

Further, the configuration for shutting off the bypass M for a time depending on the magnitude of the stroke (pressure side stroke) of the immediately preceding compression stroke of the on-off valve 2 is not limited to the above, and other configurations may be adopted. .

  Moreover, in the said embodiment, although the check valve 3 is provided in the 2nd channel | path m3 and is arrange | positioned in the other chamber side rather than the on-off valve 2, you may arrange | position in the one chamber side rather than the on-off valve 2. . Further, the configuration of the check valve 3 is not limited to the above, and a configuration such as an annular plate-like leaf valve can be appropriately employed.

  Moreover, in the said embodiment, when the on-off valve 2 moves to the other chamber side from the neutral position, the spring 20 is provided to urge the on-off valve 2 to return to the neutral position. The movement of the on-off valve 2 toward the other chamber may be restricted.

  In the above embodiment, the flow rate of the working fluid moving between the bypass chamber m1 and the one chamber A is changed by the variable throttle V4 provided in the first passage bypass m4, and the behavior of the on-off valve 2 is changed. However, the shock absorber may not include the first passage bypass m4 and the variable throttle V4.

  Further, the control rod 81 constituting the variable throttle V4 may be used to restrict the movement of the on-off valve 2 to the one chamber side, and the amount of movement of the on-off valve 2 to the one chamber side may be made variable.

  In the above embodiment, the throttle V3 provided in the back pressure flow path n2 may be a variable throttle. In addition, the shock absorber is replaced with the back pressure channel n2, and the working fluid can move only from the back pressure chamber n1 to the other chamber B, and the working fluid can move only from the other chamber B to the back pressure chamber n1. It is also possible to provide a flow path, provide a variable throttle in each flow path, and independently adjust the flow rate of the working fluid passing through each flow path.

  In the above embodiment, the spring 20 for returning the on-off valve 2 to the neutral position is provided only in the back pressure chamber n2, but the spring 20 may be provided on the upper and lower sides in FIG.

  Further, in the above embodiment, the check valve 3 includes the urging spring 31 and is urged in the closing direction by the urging spring 31. However, the check valve 3 may include an urging spring that urges in the opening direction. Good.

  In addition, a flow path that communicates the bypass chamber m1 and the back pressure chamber n1 may be formed in the open / close valve 2, and the behavior of the open / close valve 2 may be adjusted by this flow path.

A One chamber B Other chamber H Housing L Channel M Bypass channel m1 Bypass chamber m2 First channel m3 Second channel m4 First channel bypass n1 Back pressure chamber n2 Back pressure channel S Cylinder R Piston rods V1, V2 Generation of damping force Means V3 restrictor (flow restriction means)
V4 Variable throttle 1 Piston (valve disc)
2 On-off valve 3 Check valve 4 Sub piston 5 Sub piston case 6 Inner cylinder 7 Outer cylinder 8 Bush 9 Tip member 10, 40 Leaf valve 20 Spring 30 Valve head 31 Energizing spring 50 Case chamber 60 Communication hole 70 Cylindrical passage 71 Outside Side hole 80 Needle 81 Control rod 90 Oil lock piece

Claims (6)

One chamber and the other chamber in which the working fluid is stored, a valve disk that divides the one chamber and the other chamber, a flow path that connects the one chamber and the other chamber, and a working fluid that passes through the flow path A shock absorber that generates a damping force by moving the working fluid between the one chamber and the other chamber during expansion and contraction.
A bypass path that bypasses the damping force generating means and communicates the one chamber and the other chamber;
The bypass passage includes an opening and closing valve for communication or block the bypass passage, and a check valve that allows the movement of the actuating fluid to the other chamber is provided from the hand chamber above the aforementioned extension process The shock absorber characterized in that the time required for the on-off valve to open the bypass passage becomes longer as the stroke of the immediately preceding compression stroke becomes larger . A housing formed in a hollow shape so that the on-off valve is in sliding contact with an inner peripheral surface, a bypass chamber and a back pressure chamber formed in the housing and defined by the on-off valve, and the back pressure chamber and the other chamber And a back pressure channel that communicates,
The bypass path includes the bypass chamber, a first passage communicating the bypass chamber and the one chamber, and a second passage communicating the bypass chamber and the other chamber,
The on-off valve opens and closes the communication hole of the housing as the second passage side opening of the bypass chamber, the interior of the housing by moving to one chamber side while blocking the bypass passage to close the communication hole The shock absorber according to claim 1, wherein:   The shock absorber according to claim 2, wherein the back pressure channel is provided with a flow rate regulating means for regulating a flow rate of the working fluid passing through the back pressure channel.   The check valve is provided in the second passage, and includes a valve head that opens and closes the second passage, and a biasing spring that biases the valve head in a closing direction. The shock absorber according to claim 3.   The spring according to claim 2, further comprising a spring that urges the on-off valve to return to the neutral position when the on-off valve moves in the housing to the other chamber side of the neutral position. The shock absorber according to any one of the above. The first passage is provided with other damping force generating means for imparting resistance to the working fluid passing through the first passage.
The bypass passage includes a first passage bypass that bypasses the other damping force generating means and communicates the one chamber and the bypass chamber. The first passage bypass includes the first passage. The shock absorber according to any one of claims 2 to 5, further comprising a variable throttle that changes a flow rate of the working fluid that passes through the bypass.

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