JP6302223B2 - Suspension device - Google Patents

Description

  The present invention relates to a suspension device.

  Conventionally, as a suspension device that suppresses a change in the posture of a vehicle, a hydraulic damper is interposed between the vehicle body and the left and right wheels, and each hydraulic damper is movably inserted into the cylinder and the cylinder. A first flow comprising a piston partitioning into a rod side chamber and a piston side chamber, and a piston rod connected to the piston, and having a damping valve between the rod side chamber of one hydraulic damper and the piston side chamber of the other hydraulic damper. In addition, the piston side chamber of one hydraulic damper and the rod side chamber of the other hydraulic damper communicate with each other through a second flow path provided with a damping valve, and accumulators are respectively inserted in the middle of each flow path through the damping valve. What has been connected is known (for example, see Patent Documents 1 and 2).

  In the suspension device configured as described above, when each hydraulic damper expands and contracts in the same phase, either one of the volume of hydraulic oil in which the piston rod retracts from the cylinder or enters the cylinder is provided. The hydraulic fluid that becomes excessive and insufficient in each cylinder of the hydraulic damper is compensated for by each accumulator. On the other hand, when each hydraulic damper expands and contracts in the opposite phase, the amount of hydraulic oil flowing out from the cylinder is larger than when expanding and contracting in the same phase, and the amount of hydraulic oil absorbed by each accumulator is also large. Become.

  Therefore, when each hydraulic damper expands and contracts in the opposite phase, the volume change of the air chamber in each accumulator becomes larger and the spring reaction force of each accumulator becomes larger than when each hydraulic damper expands and contracts in the same phase. As the pressure increases, the amount of hydraulic fluid that passes through each damping valve increases, and each hydraulic damper exerts a large damping force to suppress rolling of the vehicle body. On the other hand, when each hydraulic damper expands and contracts in the same phase, on the contrary, the damping force generated by each hydraulic damper and the spring reaction force of the accumulator are both reduced, so that vibrations input to the wheels due to road surface unevenness etc. Transmission to the vehicle body side can be suppressed.

JP 2008-94304 A Japanese Patent Laid-Open No. 5-213040

  However, in the conventional suspension device, for example, when only one hydraulic damper expands and contracts when the wheel gets over the protrusion, each hydraulic damper exerts a large damping force in the same manner as when both hydraulic dampers expand and contract in opposite phases. It will be demonstrated.

  If each hydraulic damper exerts a large damping force in such a situation where only one wheel gets over the protrusion, there is a problem that the vibration of the wheel when getting over the protrusion is transmitted to the vehicle body and the ride comfort in the vehicle deteriorates. .

  Therefore, the present invention has been developed to improve the above-described problems, and an object of the present invention is to provide a suspension device that can improve the riding comfort in a vehicle.

In order to achieve the above-described object, the problem-solving means of the present invention includes a pair of fluid pressure dampers including an extension side chamber and a pressure side chamber that are interposed between a vehicle body and a wheel of a vehicle and partitioned by a piston in a cylinder. A first flow path connecting the extension side chamber of one fluid pressure damper and the pressure side chamber of the other fluid pressure damper, and connecting the pressure side chamber of the one fluid pressure damper and the extension side chamber of the other fluid pressure damper A second flow path, a first accumulator connected to the first flow path via a first connection path, a second accumulator connected to the second flow path via a second connection path, and the first A first valve element provided in one connection path and capable of providing resistance to a flow of fluid from the first connection path toward the first accumulator; and provided in the second connection path and the second Flow of fluid from the connection path toward the second accumulator A suspension device including a second valve element capable of giving resistance to the first sub-cylinder connected to the first flow path and slidably inserted into the first sub-cylinder. that the first free piston displacement or the first of the first free piston has a first flow path side pressure chamber connected to the first sub-cylinder the first channel that is partitioned by the first free piston in the A first damping force variable mechanism that varies the damping force generated by each fluid pressure damper by the pressure in the sub cylinder, a second sub cylinder connected to the second flow path, and a slide in the second sub cylinder The second free piston having a second free piston inserted freely and a second flow path side pressure chamber connected to the second flow path defined by the second free piston in the second sub cylinder. Displacement There is characterized in that a second damping force varying mechanism for the damping force the fluid pressure damper is generated by the pressure in the second sub-cylinder variable.

  When vibration in the low frequency range is input to each fluid pressure damper, the damping force generated by each fluid pressure damper is increased, and when vibration in the high frequency range is input to each fluid pressure damper, The damping force generated by the fluid pressure damper can be reduced.

  Therefore, in a situation where the vehicle turns and the vehicle body rolls, each fluid pressure damper can suppress the rolling by increasing the damping force, and only one wheel can get over the uneven surface of the road surface or pass through the bumpy road. In a situation where high-frequency vibrations are input, and each fluid pressure damper is in anti-phase or only one of them expands and contracts at high speed, the damping force is reduced.

  According to the suspension device of the present invention, ride comfort in a vehicle can be improved.

It is a circuit diagram of the suspension device in the first embodiment. It is a circuit diagram of a suspension device in a modification of the first embodiment. It is a circuit diagram of the suspension apparatus in the other modification of 1st Embodiment. It is a circuit diagram of a suspension device in another modification of the first embodiment. It is sectional drawing of the suspension apparatus in 1st embodiment. It is an expanded longitudinal cross-sectional view of the piston part of the fluid pressure damper in the suspension device of the first embodiment. It is an expanded longitudinal cross-sectional view of the cylinder end part of the fluid pressure damper in the suspension device of the first embodiment. It is an expansion longitudinal cross-sectional view of the 1st accumulator (2nd accumulator) in the suspension apparatus of 1st embodiment. It is a circuit diagram of the suspension apparatus in 2nd embodiment. It is a circuit diagram of a suspension device in a modification of the second embodiment. It is an expansion longitudinal cross-sectional view of the 1st accumulator (2nd accumulator) in the suspension apparatus of the modification of 2nd Embodiment. It is a circuit diagram of the suspension apparatus in the other modification of 2nd Embodiment. It is a circuit diagram of the suspension device in another modification of the second embodiment. It is a circuit diagram of a suspension device in still another modification of the second embodiment. It is a circuit diagram of a suspension device in still another modification of the second embodiment. It is a circuit diagram of a suspension device in still another modification of the second embodiment. It is an expanded longitudinal cross-sectional view of the 1st accumulator (2nd accumulator) in the suspension apparatus of another modification of 2nd Embodiment. It is a circuit diagram of the suspension apparatus in 3rd embodiment. It is an expansion longitudinal cross-sectional view of the 1st accumulator (2nd accumulator) in the suspension apparatus of 3rd embodiment.

  Hereinafter, a suspension device of the present invention will be described with reference to the drawings. As shown in FIG. 1, the suspension device S1 in the first embodiment includes a pair of fluid pressure dampers D1, D2, an extension side chamber RR1 of one fluid pressure damper D1, and a pressure side chamber LR2 of the other fluid pressure damper D2. A first flow path P1 connecting the first flow path P1, a second flow path P2 connecting the pressure side chamber RR2 of one fluid pressure damper D1 and the expansion side chamber LR1 of the other fluid pressure damper D2, and a first connection to the first flow path P1. The first accumulator A1 connected via the path J1, the second accumulator A2 connected to the second flow path P2 via the second connection path J2, and the first connection path provided in the first connection path J1. A first valve element V1 capable of providing resistance to a fluid flow from J1 to the first accumulator A1, and a fluid provided in the second connection path J2 and directed from the second connection path J2 to the second accumulator A2. Flow of A second valve element V2 capable of providing resistance, a first damping force variable mechanism C1 connected to the first flow path P1, and a second damping force variable mechanism C2 connected to the second flow path P2. For example, a fluid pressure damper D1 is interposed between the left front wheel axle of the four-wheeled vehicle and the vehicle body, and a fluid pressure damper D2 is interposed between the right front wheel axle and the vehicle body. It is what is done.

  As shown in FIG. 1, the fluid pressure dampers D1 and D2 are slidably inserted into the cylindrical cylinder 2, and the cylinder 2 is divided into expansion side chambers RR1 and LR1, and pressure side chambers RR2 and LR2. And a piston rod 4 having one end connected to the piston 3, and the cylinder 2 is filled with, for example, hydraulic fluid as a working fluid in an oil-tight state.

  And each fluid pressure damper D1, D2 is connected by the 1st flow path P1 and the 2nd flow path P2, and, specifically, the 1st flow path P1 is the expansion side chamber RR1 of one fluid pressure damper D1, and the other fluid. The pressure side chamber LR2 of the pressure damper D2 is connected, and the other second flow path P2 connects the pressure side chamber RR2 of one fluid pressure damper D1 and the expansion side chamber LR1 of the other fluid pressure damper D2. That is, the first flow path P1 and the second flow path P2 hook-connect the extension side chambers RR1, LR1 and the pressure side chambers RR2, LR2 of the pair of fluid pressure dampers D1, D2.

  In this case, attenuation valves 5 and 6 are provided in the first flow path P1, and attenuation valves 7 and 8 are also provided in the second flow path P2. Therefore, when the hydraulic oil is pushed out from the cylinder 2 of the fluid pressure dampers D1 and D2 to the first flow path P1 and the second flow path P2, or when the hydraulic oil is supplied into the cylinder 2, the damping valves 5 and 6 , 7 and 8 are designed to provide resistance to the flow of hydraulic oil. The damping valves 5, 6, 7, and 8 are throttles as shown in FIG. 1 and provide resistance to the bidirectional flow of hydraulic oil, but are shown in FIG. 2. As described above, the first flow path P1 and the second flow path P2 may be provided in parallel with the check valve 9 so as to provide resistance only to the flow of hydraulic oil pushed out from the cylinder 2. Good. In this case, the check valve 9 arranged in parallel with the damping valves 5, 6, 7, and 8 is opened for the flow in which the hydraulic oil is supplied into the cylinder 2, and the hydraulic oil is supplied into the cylinder 2 without resistance. Will come to be. Furthermore, in the present embodiment, the damping valves 5, 6, 7, and 8 are provided, but these can be omitted.

  The first accumulator A1 is connected to the first flow path P1 through a first connection path J1 connected between the damping valves 5 and 6 in the middle of the first flow path P1. In the first connection path J1, a first valve element V1 capable of giving resistance to the flow of hydraulic oil from the first flow path P1 toward the first accumulator A1 is provided. In this case, the first valve element V1 may be a throttle and provide resistance to the bidirectional flow of hydraulic oil. However, as shown in FIG. The damping valve may provide resistance only to the flow of hydraulic fluid toward the one accumulator A1, and in this case, in addition to the first valve element V1, the first accumulator A1 to the first accumulator A1 It is only necessary to provide a damping valve Va that provides resistance only to the flow of hydraulic oil toward one flow path P1. Furthermore, when the first valve element V1 is a damping valve that provides resistance only to the flow of hydraulic fluid from the first flow path P1 to the first accumulator A1, the first valve element V1 is connected to the first connection path J1 in parallel with the first valve element V1. You may make it provide the non-return valve which accept | permits only the flow of the hydraulic fluid which goes to the 1st flow path P1 from one accumulator A1. When the first valve element V1 is a throttle or choke and it is desired to provide resistance only to the flow of hydraulic oil from the first accumulator A1 to the first flow path P1, the first valve A check valve that allows only the flow of hydraulic fluid from the first accumulator A1 to the first flow path P1 is provided in series with the element V1, and in parallel therewith, the first accumulator is connected to the first connection path J1 from the first flow path P1. It is also possible to provide a check valve that allows only the flow of hydraulic oil toward A1.

  The second accumulator A2 is connected to the second flow path P2 through a second connection path J2 connected between the damping valves 7 and 8 in the middle of the second flow path P2. The second connection path J2 is provided with a second valve element V2 that can provide resistance to the flow of hydraulic oil from the second flow path P2 toward the second accumulator A2. In this case, the second valve element V2 may be a throttle and may provide resistance to the bidirectional flow of hydraulic oil, but as shown in FIG. The damping valve may provide resistance only to the flow of hydraulic oil toward the second accumulator A2, and in this case, in addition to the second valve element V2, the second accumulator A2 is connected to the second connection path J2. It is only necessary to provide a damping valve Vb that gives resistance only to the flow of hydraulic oil toward the second flow path P2. Furthermore, when the second valve element V2 is a damping valve that provides resistance only to the flow of hydraulic fluid from the second flow path P2 toward the second accumulator A2, in parallel with this, the second connection element J2 is connected to the second connection path J2. You may make it provide the non-return valve which accept | permits only the flow of the hydraulic fluid which goes to the 2nd flow path P2 from 2nd accumulator A2. In the case where the second valve element V2 is a throttle or choke and it is desired to provide resistance only to the flow of hydraulic oil from the second accumulator A2 to the second flow path P2, A check valve that allows only the flow of hydraulic oil from the second accumulator A2 to the second flow path P2 is provided in series with the valve element V2, and in parallel therewith, the second connection path J2 is connected to the second flow path P2 from the second flow path P2. It is also possible to provide a check valve that allows only the flow of hydraulic oil toward the second accumulator A2.

  In this embodiment, the first damping force variable mechanism C1 includes a first sub cylinder 10 connected to the first flow path P1, and a first free piston 11 slidably inserted into the first sub cylinder 10. The first flow path side pressure chamber 12 and the first accumulator side pressure chamber 13 partitioned in the first sub cylinder 10 by the first free piston 11 and the first free piston 11 are positioned to the neutral position with respect to the first sub cylinder 10. The first spring element 14 that exerts an urging force that suppresses displacement from the neutral position of the first free piston 11 and the flow path 15 that connects the first flow path side pressure chamber 12 to the first flow path P1 are provided. And an orifice 18 provided in the middle of the flow path 17 connecting the first accumulator side pressure chamber 13 to the first accumulator A1. The neutral position of the first free piston 11 is a position where the first spring element 14 positions the first free piston 11 with respect to the first sub-cylinder 10 and does not necessarily coincide with the center of the first sub-cylinder 10. You don't have to.

  In this embodiment, the second damping force variable mechanism C2 includes a second sub cylinder 20 connected to the second flow path P2, and a second free piston 21 slidably inserted into the second sub cylinder 20. The second flow path side pressure chamber 22 and the second accumulator side pressure chamber 23 partitioned in the second sub cylinder 20 by the second free piston 21, and the second free piston 21 in a neutral position with respect to the second sub cylinder 20. The second spring element 24 that exerts an urging force that suppresses the displacement from the neutral position of the second free piston 21 and the flow path 25 that connects the second flow path side pressure chamber 22 to the second flow path P2. And an orifice 28 provided in the middle of a flow path 27 connecting the second accumulator side pressure chamber 23 to the second accumulator A2. The neutral position of the second free piston 21 is a position where the second spring element 24 positions the second free piston 21 with respect to the second sub-cylinder 20 and does not necessarily coincide with the center of the second sub-cylinder 20. You don't have to.

  As described above, the suspension device S1 is configured, and the operation thereof will be described. For ease of explanation, the basic operation of the suspension device S1 will be described ignoring the first damping force variable mechanism C1 and the second damping force variable mechanism C2. First, the case where the fluid pressure dampers D1 and D2 expand and contract in the same phase, that is, the case where the displacement phase of the piston 3 with respect to the cylinder 2 is the same in each fluid pressure damper D1 and D2 will be described.

  When the fluid pressure dampers D1 and D2 both extend at the same speed, the volumes of the expansion side chambers RR1 and LR1 of the fluid pressure dampers D1 and D2 are reduced and the volumes of the pressure side chambers RR2 and LR2 are increased.

  Then, the hydraulic oil flowing out from the expansion side chamber RR1 in one fluid pressure damper D1 flows into the pressure side chamber LR2 in which the volume of the other fluid pressure damper D2 increases through the first flow path P1.

  Further, the hydraulic oil flowing out from the expansion side chamber LR1 in the other fluid pressure damper D2 flows into the pressure side chamber RR2 in which the volume of the one fluid pressure damper D1 increases through the second flow path P2.

  However, in each of the fluid pressure dampers D1 and D2, the volume that increases in the compression side chambers RR2 and LR2 is larger than the volume that decreases in the expansion side chambers RR1 and LR1 by the volume of the piston rod 4 withdrawing from the cylinder 2. The hydraulic oil is insufficient in the pressure side chambers RR2 and LR2.

  Therefore, the hydraulic oil corresponding to the insufficient volume is supplied from the second accumulator A2 in the pressure side chamber RR2 of the fluid pressure damper D1 and from the first accumulator A1 in the pressure side chamber LR2 of the fluid pressure damper D2. .

  On the contrary, when the fluid pressure dampers D1 and D2 are both compressed at the same speed, the volumes of the expansion side chambers RR1 and LR1 of the fluid pressure dampers D1 and D2 are increased and the volumes of the pressure side chambers RR2 and LR2 are decreased. Become.

  Then, the hydraulic oil flowing out from the pressure side chamber RR2 in one fluid pressure damper D1 flows into the expansion side chamber LR1 in which the volume of the other fluid pressure damper D2 increases through the second flow path P2.

  Further, the hydraulic oil flowing out from the pressure side chamber LR2 in the other fluid pressure damper D2 flows into the expansion side chamber RR1 in which the volume of the one fluid pressure damper D1 increases through the first flow path P1.

  However, in each of the fluid pressure dampers D1 and D2, the volume that decreases in the compression side chambers RR2 and LR2 is larger than the volume that increases in the extension side chambers RR1 and LR1 by the volume of the piston rod 4 entering the cylinder 2. The hydraulic oil becomes excessive in the pressure side chambers RR2 and LR2.

  Accordingly, the excess amount of hydraulic oil is absorbed by the second accumulator A2 in the fluid pressure damper D1 and by the first accumulator A1 in the fluid pressure damper D2.

  Next, the case where the fluid pressure dampers D1 and D2 expand and contract in opposite phases, that is, the case where the displacement phase of the piston 3 with respect to the cylinder 2 is completely opposite in each fluid pressure damper D1 and D2 will be described.

  When one fluid pressure damper D1 expands and the other fluid pressure damper D2 is compressed in reverse at the same speed as one fluid pressure damper D1, the volume of the expansion side chamber RR1 of one fluid pressure damper D1 decreases and the pressure side The volume of the chamber RR2 increases, the volume of the expansion side chamber LR1 of the other fluid pressure damper D2 increases, and the volume of the compression side chamber LR2 decreases.

  In this case, since the volumes of the expansion side chamber RR1 in one fluid pressure damper D1 connected by the first flow path P1 and the compression side chamber LR2 in the other fluid pressure damper D2 are both reduced, the expansion in one fluid pressure damper D1 is reduced. The hydraulic oil flowing out from the pressure chamber LR2 in the side chamber RR1 and the other fluid pressure damper D2 is absorbed by the first accumulator A1.

  Further, since the volumes of the compression side chamber RR2 in one fluid pressure damper D1 and the expansion side chamber LR1 in the other fluid pressure damper D2 connected by the second flow path P2 both increase, the pressure side in one fluid pressure damper D1 The hydraulic fluid that flows into the expansion side chamber LR1 in the chamber RR2 and the other fluid pressure damper D2 is supplied from the second accumulator A2. The amount of hydraulic fluid flowing into the first accumulator A1 and the amount of hydraulic fluid flowing out from the second accumulator A2 are larger than when the fluid pressure dampers D1 and D2 expand and contract in the same phase.

  On the other hand, when the expansion and contraction of the fluid pressure dampers D1 and D2 is reversed, the hydraulic oil is supplied from the first accumulator A1 connected to the first flow path P1 to the fluid pressure dampers D1 and D2, and is supplied to the second flow path P2. The hydraulic oil pushed out from the fluid pressure dampers D1 and D2 is absorbed by the connected second accumulator A2, and the amount of hydraulic oil flowing out from the first accumulator A1 and the second accumulator A2 flow into the second accumulator A2. The amount of hydraulic oil is larger than when the fluid pressure dampers D1 and D2 expand and contract in the same phase.

  Here, the damping force of one fluid pressure damper D1 is proportional to the differential pressure between the expansion side chamber RR1 and the compression side chamber RR2, and the damping force of the other fluid pressure damper D2 is also the differential pressure between the expansion side chamber LR1 and the compression side chamber LR2. It will be proportional to

  As described above, when each of the fluid pressure dampers D1 and D2 expands and contracts in the opposite phase, the first accumulator A1 and the second accumulator A2 and each of the respective fluid pressure dampers D1 and D2 expands and contracts in the same phase. The amount of hydraulic oil exchanged by the fluid pressure dampers D1 and D2 increases. In addition, the spring constant of the accumulator on the side into which the hydraulic oil flows in the first accumulator A1 and the second accumulator A2 increases as the amount of hydraulic oil flowing in increases, and if the flow rate passing therethrough increases, the first valve element V1 and The pressure loss at the second valve element V2 also increases.

  Therefore, when each of the fluid pressure dampers D1 and D2 expands and contracts in the opposite phase, the differential pressure between the expansion side chamber RR1 and the compression side chamber RR2 of one fluid pressure damper D1, and the expansion side chamber LR1 and the compression side chamber LR2 of the other fluid pressure damper D2 As for the differential pressure, when the fluid pressure dampers D1 and D2 expand and contract in the same phase, the differential pressure between the expansion side chamber RR1 and the compression side chamber RR2 of one fluid pressure damper D1, and the expansion side chamber LR1 and the compression side chamber of the other fluid pressure damper D2 The damping force generated by one fluid pressure damper D1 and the other fluid pressure damper D2 when the fluid pressure dampers D1 and D2 expand and contract in opposite phases becomes greater than the differential pressure of LR2, and the fluid pressure dampers D1 , D2 is higher than the damping force generated by one fluid pressure damper D1 and the other fluid pressure damper D2 when expanding and contracting in the same phase.

  In the above description, the fluid pressure dampers D1 and D2 are expanded and contracted by the same phase and reverse movement, and the piston speed is the same. However, the generated damping force of each fluid pressure damper D1 and D2 is Depending on the amount of hydraulic oil supplied to and discharged from each accumulator A1, A2, only one of the fluid pressure dampers D1, D2 expands or contracts, or each of the fluid pressure dampers D1, D2 shifts in phase. When the fluid pressure dampers D1 and D2 expand and contract, the fluid pressure dampers D1 and D2 expand and contract in the same phase according to the amount of hydraulic oil supplied to and discharged from the accumulators A1 and A2. As a result, an intermediate damping force is generated when the fluid pressure dampers D1 and D2 expand and contract in opposite phases.

  As described above, if the first damping force variable mechanism C1 and the second damping force variable mechanism C2 are ignored, each fluid pressure damper D1 when the fluid pressure dampers D1 and D2 expand and contract in opposite phases is basically obtained. , D2 is higher than the generated damping force of the fluid pressure dampers D1, D2 when the fluid pressure dampers D1, D2 expand and contract in the same phase. For rolling, the generated damping force of each of the fluid pressure dampers D1 and D2 is increased to reduce the rolling speed of the vehicle body, and the spring constant of the accumulator into which hydraulic oil flows in the first accumulator A1 or the second accumulator A2 The degree of rolling of the vehicle body (inclination amount) can be reduced and excellent steering stability can be obtained. In addition, when the fluid pressure dampers D1 and D2 are arranged at two locations of the vehicle body and the front and rear wheels, squat and pitching can be suppressed, and the right front wheel and the left rear wheel or the left front wheel and the right rear wheel of the vehicle body can be suppressed. When the fluid pressure dampers D1 and D2 are disposed at the two locations, squat and pitching can be suppressed in addition to rolling of the vehicle body.

  On the other hand, when the posture changes such that the entire vehicle body sinks or rises, the hydraulic oil flows in the generated damping force of each fluid pressure damper D1, D2 and the first accumulator A1 or the second accumulator A2. Since the spring constant of the accumulator is smaller than the spring constant when each fluid pressure damper D1, D2 expands and contracts in the opposite phase, it becomes difficult to transmit the vibration input to the wheel to the vehicle body, and the vibration insulation to the vehicle body is improved. This improves the riding comfort of the vehicle.

  Next, functions of the first damping force variable mechanism C1 and the second damping force variable mechanism C2 will be described. In the situation where the hydraulic fluid flows into the first accumulator A1 when the fluid pressure dampers D1 and D2 expand and contract, the first damping force variable mechanism C1 flows into the first flow path side pressure chamber 12 and the first hydraulic fluid flows into the first accumulator A1. In a situation where the first free piston 11 is pressed in the direction of compressing the accumulator side pressure chamber 13 and the hydraulic oil is discharged from the first accumulator A1, the hydraulic oil flows into the first accumulator side pressure chamber 13 and the first flow path side. In order to press the first free piston 11 in the direction of compressing the pressure chamber 12, the first free piston 11 is displaced in the first sub-cylinder 10. The first sub-cylinder 10 is connected to the first flow path P1 and the first accumulator A1, but the first free piston 11 partitions the first sub-cylinder 10 and thus the first flow path P1 and the first accumulator. Although A1 is not directly connected via the first sub-cylinder 10, the hydraulic fluid can be exchanged between the first flow path P1 and the first accumulator A1 when the first free piston 11 is displaced. The first sub-cylinder 10 forms an apparent flow path that connects the first flow path P1 and the first accumulator A1.

  Similarly, since the second free piston 21 can be displaced in the second sub-cylinder 20 for the second damping force variable mechanism C2, the second sub-cylinder 20 moves the second flow path P2 and the second accumulator A2. An apparent flow path to be connected is formed.

  Here, regardless of whether the frequency of vibration input to each fluid pressure damper D1, D2, that is, the frequency of expansion / contraction vibration of each fluid pressure damper D1, D2, is low or high, each fluid pressure damper D1. , D2 have the same piston speed, the amplitude of the fluid pressure dampers D1, D2 at the time of low frequency vibration input is larger than the amplitude of the fluid pressure dampers D1, D2 at the time of high frequency vibration input.

  In this way, when the frequency of vibration input to each fluid pressure damper D1, D2 is low, the amplitude is large. Therefore, the flow and fluid pressure dampers D2 and D2 that flow between the fluid pressure damper D1 and the first accumulator A1 in one expansion and contraction cycle The flow rate to and from the second accumulator A2 increases. The displacement of the first free piston 11 and the second free piston 21 also increases in proportion to the flow rate.

  In the first damping force variable mechanism C1, since the first free piston 11 is urged by the first spring element 14, the first spring element received by the first free piston 11 when the displacement of the first free piston 11 increases. 14 is increased, and accordingly, a differential pressure is generated between the pressure in the first flow path side pressure chamber 12 and the pressure in the first accumulator side pressure chamber 13, and the first flow path P 1 and the first flow path side pressure chamber 12 are The differential pressure and the differential pressure between the first accumulator A1 and the first accumulator side pressure chamber 13 are reduced. Then, the flow rate passing through the first sub-cylinder 10 as an apparent flow path described above is reduced. Since the flow rate passing through the apparent flow path is small, the flow rate passing through the first valve element V1 is large, and the ratio of the flow rate passing through the apparent flow path to the flow rate passing through the first valve element V1 is small.

Also in the second damping force varying mechanism C2, since the second free piston 21 is biased by the second spring element 24, the displacement of the second free piston 21 is increased, the second the second free piston 2 1 receives The biasing force from the spring element 24 is also increased, and accordingly, a differential pressure is generated between the pressure in the second flow path side pressure chamber 22 and the pressure in the second accumulator side pressure chamber 23, and the second flow path P2 and the second flow path side. The differential pressure between the pressure chamber 22 and the differential pressure between the second accumulator A2 and the second accumulator side pressure chamber 23 is reduced. Then, the flow rate that passes through the second sub-cylinder 20 as the apparent flow path described above decreases. Since the flow rate passing through the apparent flow path is small, the flow rate passing through the second valve element V2 is large, and the ratio of the flow rate passing through the apparent flow path to the flow rate passing through the second valve element V2 is small.

  Conversely, when high-frequency vibration is input to each of the fluid pressure dampers D1 and D2, the amplitude is smaller than when low-frequency vibration is input, so the flow rate and fluid flow between the fluid pressure damper D1 and the first accumulator A1 in one expansion and contraction cycle. The flow rate between the pressure damper D2 and the second accumulator A2 is reduced. The displacement of the first free piston 11 and the second free piston 21 is also substantially proportional to the flow rate.

  In the first damping force variable mechanism C1, the urging force that the first free piston 11 receives from the first spring element 14 is also smaller than when low-frequency vibration is input. Accordingly, the pressure in the first flow path side pressure chamber 12 and the pressure in the first accumulator side pressure chamber 13 become substantially equal, and the differential pressure between the first flow path P1 and the first flow path side pressure chamber 12 and the first accumulator A1 and the first pressure. The differential pressure with the accumulator-side pressure chamber 13 becomes larger than when low-frequency vibration is input. Then, the ratio of the flow rate passing through the first sub-cylinder 10 as the apparent flow path to the flow rate passing through the first valve element V1 is higher when high frequency vibration is input than when low frequency vibration is input. growing.

  Also in the second damping force variable mechanism C2, the urging force that the second free piston 21 receives from the second spring element 24 is also smaller than that during low-frequency vibration input. Accordingly, the pressure in the second flow path side pressure chamber 22 and the pressure in the second accumulator side pressure chamber 23 become substantially equal, and the differential pressure between the second flow path P2 and the second flow path side pressure chamber 22 and the second accumulator A2 are increased. And the second accumulator-side pressure chamber 23 become larger than when low-frequency vibration is input. Then, the ratio of the flow rate passing through the second sub-cylinder 20 as the apparent flow path to the flow rate passing through the second valve element V2 is higher when high frequency vibration is input than when low frequency vibration is input. growing.

  Thus, when vibrations in a low frequency range are input to the fluid pressure dampers D1 and D2, the first sub cylinder 10 and the first sub cylinder 10 and the second valve element V2 are supplied to the flow rates passing through the first valve element V1 and the second valve element V2. When the flow rate passing through the two sub-cylinders 20 is relatively small and vibrations in a high frequency range are input to the fluid pressure dampers D1 and D2, the flow rates passing through the first valve element V1 and the second valve element V2 On the other hand, since the flow rates passing through the first sub cylinder 10 and the second sub cylinder 20 are relatively large, the fluid pressure dampers D1 and D2 are more at the time of high frequency vibration input than at the time of low frequency vibration input. The differential pressure between the extension side chambers RR1 and LR1 and the pressure side chambers RR2 and LR2 becomes smaller, and the generated damping force of the fluid pressure dampers D1 and D2 becomes lower.

  That is, the damping force is reduced by the action of the first damping force variable mechanism C1 and the second damping force variable mechanism C2 with respect to the input of the low frequency vibration. Each of the fluid pressure dampers D1 and D2 exhibits a damping force as described in the basic operation.

  Therefore, in a situation where the vehicle turns and the vehicle body rolls, each of the hydraulic pressure dampers D1 and D2 can suppress the rolling by increasing the damping force, and only one wheel can get over the uneven surface of the road surface, If the fluid pressure dampers D1 and D2 are out of phase or only one of them expands or contracts at high speed, the damping force is reduced. Riding comfort in the vehicle can be improved.

  The damping valves 5, 6, 7, and 8 can be eliminated, but by providing them, the characteristics of the generated damping force of the fluid pressure dampers D1 and D2 can be arbitrarily set. Part or all of the damping valves 5, 6, 7, and 8 can be arbitrarily abolished depending on the desired damping force characteristics.

  Further, in this case, each of the orifices 16 and 18 and the first spring element 14 in the first damping force variable mechanism C1 and further the orifices 26 and 28 and the second spring element 24 in the second damping force variable mechanism C2 are set. The frequency at which the effect of reducing the generated damping force of the fluid pressure dampers D1 and D2 can be set arbitrarily, but some or all of the orifices 16 and 18 and the orifices 26 and 28 can be eliminated. Furthermore, as shown in FIG. 3, a check valve W that permits only a flow in the direction of discharging hydraulic oil from the first sub cylinder 10 and the second sub cylinder 20 in parallel with the orifices 16, 18, 26, 28. , X, Y, Z can be provided so that the orifices 16, 18, 26, 28 function only when hydraulic fluid flows into the first sub cylinder 10 and the second sub cylinder 20. Yes, in this case, an orifice that functions according to the direction of displacement from the neutral position of the first free piston 11 and the second free piston 21 can be selected, and the displacement of the first free piston 11 and the second free piston 21 It is possible to give directivity to the characteristics. For example, the damping force characteristics on the extension side and the compression side when the fluid pressure dampers D1 and D2 expand and contract in the same phase are individually set. It is possible.

  The first spring element 14 in the first damping force variable mechanism C1 and the second spring element 24 in the second damping force variable mechanism C2 can be omitted. In this case, until the first free piston 11 and the second free piston 21 reach the stroke end limited by the first sub cylinder 10 and the second sub cylinder 20, It can be displaced freely within the cylinder 20. When a high-frequency vibration with a small amplitude is input to each fluid pressure damper D1, D2, the amount of expansion / contraction of each fluid pressure damper D1, D2 is small, and each fluid pressure damper D1, D2 and each accumulator A1, A2 Since the amount of hydraulic fluid to be exchanged is small, the first free piston 11 and the second free piston 21 can be freely displaced in the first sub cylinder 10 and the second sub cylinder 20 without reaching the stroke end. Since the hydraulic oil passes through the apparent flow path in preference to the first valve element V1 and the second valve element V2, the hydraulic oil is exchanged between the fluid pressure dampers D1 and D2 and the accumulators A1 and A2. . Therefore, when high-frequency vibration with a small amplitude is input to each fluid pressure damper D1, D2, the generated damping force of each fluid pressure damper D1, D2 is reduced. On the other hand, when low-frequency vibration having a large amplitude is input to each of the fluid pressure dampers D1 and D2, the amount of expansion and contraction of each of the fluid pressure dampers D1 and D2 is large, and each of the fluid pressure dampers D1 and D2 and each accumulator The amount of hydraulic fluid exchanged with A1 and A2 increases. Then, the first free piston 11 and the second free piston 21 reach the stroke end, the movement is restricted by the first sub cylinder 10 and the second sub cylinder 20, and the hydraulic oil passes through the apparent flow path. The hydraulic oil passes through the first valve element V1 and the second valve element V2 preferentially, and hydraulic fluid is exchanged between the fluid pressure dampers D1 and D2 and the accumulators A1 and A2. Therefore, when a low-frequency vibration having a large amplitude is input to each fluid pressure damper D1, D2, each fluid pressure damper D1, D2 can exhibit a damping force as described in the basic operation.

Also, as in the suspension device S1 of another modification of the first embodiment are shown in FIG. 4, the first accumulator pressure chamber 13 of the first damping force varying mechanism C1 and the second damping force varying mechanism C2 and The second accumulator-side pressure chamber 23 can be a sealed space filled with gas, opened to the atmosphere, or connected to the first accumulator A1 and the second accumulator A2 without resistance.

  In the suspension device S1, when the fluid pressure damper D1 extends and the fluid pressure damper D2 contracts, hydraulic fluid is pushed out from the expansion side chamber RR1 and the pressure side chamber LR2 and flows into the first actuator A1 via the first flow path P1. On the contrary, when the fluid pressure damper D1 contracts and the fluid pressure damper D2 extends, the hydraulic oil is pushed out from the expansion side chamber LR1 and the pressure side chamber RR2 to the second actuator A2 via the second flow path P2. It comes to flow. In other words, when each of the fluid pressure dampers D1 and D2 expands and contracts in the opposite phase, or only one of them expands and contracts, the hydraulic oil is always pushed out from the high-pressure chamber to be compressed and the first and second accumulators A1 and A2 It flows into one of the corresponding accumulators in A2.

  And since the amount of hydraulic fluid which flows into 1st accumulator A1 or 2nd accumulator A2 can be reduced by absorbing hydraulic fluid with the 1st subcylinder 10 or the 2nd subcylinder 20, one above-mentioned execution Similarly to the suspension device S1 in the embodiment, when high-frequency vibration is input to each fluid pressure damper D1, D2, the generated damping force of each fluid pressure damper D1, D2 can be reduced. When the first accumulator side pressure chamber 13 and the second accumulator side pressure chamber 23 are sealed spaces filled with gas, respectively, the first accumulator side pressure chamber 13 and the second accumulator side pressure chamber 23 may form a gas spring. When the first free piston 11 and the second free piston 21 move in the direction of compressing the first accumulator side pressure chamber 13 and the second accumulator side pressure chamber 23, the first free piston 11 and the first sub cylinder 10 And the collision between the second free piston 21 and the second sub-cylinder 20 can be prevented. Also in the suspension device S1 according to the modification of the first embodiment of FIG. 4, the first spring element 14 and the second spring element 24 can be eliminated.

  Further, the orifice 16 provided between the first flow path side pressure chamber 12 and the first flow path P1 and the orifice 26 provided between the second flow path side pressure chamber 22 and the second flow path P2 are omitted. It is also possible to do.

  In this embodiment, the flow of hydraulic oil from the first flow path side pressure chamber 12 toward the first flow path P1 is allowed to the orifice 16 provided between the first flow path side pressure chamber 12 and the first flow path P1. A check valve is provided in parallel, and the operation is directed from the second flow path side pressure chamber 22 toward the second flow path P2 with respect to the orifice 26 provided between the second flow path side pressure chamber 22 and the second flow path P2. A check valve that allows the oil flow may be provided in parallel. In this way, when the hydraulic oil is discharged from the first sub cylinder 10 to the first flow path P1, the first free piston 11 can be returned to the neutral position by the first spring element 14 without resistance, When hydraulic fluid is discharged from the second sub cylinder 20 to the second flow path P2, the second free piston 21 can be returned to the neutral position by the second spring element 24 without resistance, and the first free piston 11 is neutral. As a result, the second free piston 21 is biased from the neutral position toward the side to expand the second flow path side pressure chamber 22. As a result, the situation where the end of the stroke is reached and the damping force reduction effect cannot be exhibited is eliminated.

  In order to specifically configure the suspension device S1 of the first embodiment, it may be configured as shown in FIGS. In this case, the fluid pressure dampers D1 and D2 have the same structure.

  The fluid pressure dampers D1 and D2 will be described in detail. As shown in FIG. 5, the fluid pressure dampers D1 and D2 include a cylindrical cylinder 2, an outer cylinder 55 that covers the outside of the cylinder 2, and a cylinder 2 Drawing of piston 3 which is slidably inserted and divides the inside of cylinder 2 into expansion side chambers RR1 and LR1 and compression side chambers RR2 and LR2, hollow piston rod 4 having one end connected to piston 3, cylinder 2 and outer cylinder 55 1 is sealed in the lower end opening of the cylinder 2 while being fitted in the lower end opening of the cylinder 2, the head member 58 that seals the upper end side in the middle and supports the piston rod 4, the lower cap 59 that closes the lower end in FIG. And a partition member 50 sandwiched between the lower cap 59 and the lower cap 59. The working fluid is contained in the cylinder 2 and in the annular gap 56 formed between the cylinder 2 and the outer cylinder 55. , For example, hydraulic oil is filled are the oil-tight state.

  As shown in FIG. 6, the piston 3 is formed in a bottomed cylindrical shape, an insertion hole 3 b through which the piston rod 4 is inserted into the axial center portion of the bottom portion 3 a, and an extension side port that forms a piston passage provided in the bottom portion 3 a. 3c and the pressure side port 3d, an annular valve seat 3f formed on the outer peripheral side of the window 3e that communicates the outlet end of each expansion side port 3c, and the outer side of the window 3g that communicates the outlet end of each pressure side port 3d An annular valve seat 3h that is formed, a cylindrical portion 3i that protrudes downward in FIG. 6 from the outer peripheral side of the bottom portion 3a, and an annular belt band 3k that is attached to the outer periphery of the bottom portion 3a and slidably contacts the inner periphery of the cylinder 2 And is configured.

  Subsequently, the piston rod 4 is formed in a cylindrical shape and is hollow inside, and the outer diameter of the tip portion 4a of the piston rod 4 is set smaller than the outer diameter on the upper side in FIG. 5 from the tip portion 4a. The step 4b is formed in a portion where the outer diameters of the upper side and the tip 4a are different. Then, the tip 4a of the piston rod 4 is inserted into the insertion hole 3b of the piston 3, and the piston nut 30 is screwed onto the screw 4c formed on the outer periphery of the tip 4a of the piston rod 4 from below in FIG. Thus, the piston 3 is fixed to the piston rod 4.

  The piston nut 30 is formed in a cylindrical shape and is screwed into the screw portion 4c, a port 30b penetrating through the top and bottom of the main body 30a, and a cylinder portion of the piston 3 mounted on the outer periphery of the main body 30a. An annular seal 30c that contacts the inner periphery of 3i and seals between the piston 3 and the piston nut 30, and a cylindrical socket 30d that hangs down from the outer peripheral side from the opening of the port 30b at the lower end of the main body 30a in FIG. And a pair of disks 31 and 32 that are mounted on the inner periphery of the socket 30d and face each other, and a permeation flow member 33 that is accommodated in a gap between the disks 31 and 32.

  The piston nut 30 communicates with the piston rod 4 through a space 34 formed between the piston nut 3 and the piston 3 via the port 30b. The space 34 includes the extension side port 3c and the above-described piston passage. Since the compression side port 3d communicates with the expansion side chambers RR1 and LR1, the expansion side chambers RR1 and LR1 and the inside of the piston rod 4 are communicated with each other by the above configuration.

  In addition, small holes 31a and 32a are opened in the disks 31 and 32 described above, and the pressure side chamber RR2 is connected via a communication passage 35 formed by a gap in which the small holes 31a and 32a and the permeation flow member 33 are accommodated. , LR2 and the piston rod 4 and the extension side chambers RR1 and LR1 communicate with each other, and hydraulic oil flows between the extension side chambers RR1 and LR1 and the pressure side chambers RR2 and LR2 in the middle of the communication passage 35. 33.

  The permeation distribution member 33 is configured to allow hydraulic oil to pass through in a permeation state from the high-pressure side chamber to the low-pressure side chamber among the extension side chambers RR1, LR1 and the pressure side chambers RR2, LR2. Is a porous body. In other words, this permeation flow member 33 allows hydraulic oil to pass from the high pressure side chamber to the low pressure side chamber when there is a difference in pressure between the extension side chambers RR1, LR1 and the pressure side chambers RR2, LR2. Since the oil is allowed to pass through, the amount of hydraulic oil passing through the permeation flow member 33 is proportional to the time during which the pressure difference is generated.

  In other words, the permeation distribution member 33 is provided with the expansion side chambers RR1, LR1 and the pressure side chambers RR2, LR2 that are generated when the fluid pressure dampers D1, D2 expand and contract during vibration input from the road surface, starting braking, and turning while the vehicle is running. Depending on the pressure fluctuation, the alternating interval of the pressure fluctuation is short, so that the effect of hardly passing the hydraulic oil is brought about. Although the permeation flow member 33 does not have frequency characteristics, as a result, the fluid When the vibration frequency of the pressure dampers D1 and D2 is high, the osmotic flow member 33 hardly passes hydraulic oil.

  On the other hand, the osmotic flow member 33 is used for a long time when there is almost no alternating pressure fluctuation between the extension side chambers RR1, LR1 and the compression side chambers RR2, LR2, for example, when the vehicle is stopped for a long time. As a result, the hydraulic oil is allowed to pass from the high-pressure chamber to the low-pressure chamber very slowly, and as a result, when the vibration frequency of the fluid pressure dampers D1 and D2 is extremely small, The flow member 33 passes the hydraulic oil from the high pressure side chamber to the low pressure side chamber very slowly.

  Moreover, since the osmosis | permeation distribution member 33 should just be provided with the above-mentioned characteristic, it may be used as the disk provided with the orifice of the very small diameter connected to the small holes 31a and 32a, for example.

  Subsequently, a notch leaf valve 36, a non-return valve 37, a spacer 38 and a valve stopper 39 for closing the pressure side port 3d are sequentially laminated on the upper surface of the piston 3 in FIG. The tip 4a of the piston rod 4 is inserted.

  Further, on the lower surface of the piston 3 in FIG. 6, a leaf valve 40, a spacer 41, and a valve stopper 42, which are formed by laminating a plurality of leaves for closing the expansion side port 3c, are laminated in this order. The tip 4a of the piston rod 4 is inserted inward.

  Then, as described above, each member including the piston 3 is assembled to the tip portion 4a of the piston rod 4, and the piston nut 30 disposed at the lowest position in FIG. 6 is screwed to the screw portion 4c of the tip portion 4a. By wearing, each member including the piston 3 is sandwiched between the step 4 b of the piston rod 4 and the upper end of the piston nut 30 and fixed to the piston rod 4.

Here, when the fluid pressure dampers D1 and D2 expand and contract during the traveling of the vehicle and the volumes of the extension side chambers RR1 and LR1 increase or decrease, as described above, the hydraulic oil by the communication passage 35 is used for the pressure fluctuation during the traveling of the vehicle. Therefore, most of the hydraulic oil that becomes excessive and insufficient in the extension side chambers RR1 and LR1 flows out and in through the piston rod 4. When the volume in the extension side chambers RR1, LR1 decreases, the compression side port 3d is blocked by the non-return valve 37, so that the hydraulic oil pushes open the leaf valve 40 and passes through the extension side port 3c. Then, it is discharged out of the cylinder 2 through the piston rod 4. The hydraulic oil leaf valve 40 is to provide resistance to the flow of the hydraulic fluid as it passes through the expansion side port 3 c.

  On the other hand, when the volume in the extension side chambers RR1, LR1 increases, the extension side port 3c is closed by the leaf valve 40, so that most of the hydraulic fluid passes through the piston rod 4 from the outside of the cylinder 2. Further, the notch leaf valve 36 and the non-return valve 37 are pushed open to pass through the compression side port 3d and supplied into the extension side chambers RR1 and LR1.

  In the present embodiment, the structure corresponding to the damping valves 5 and 7 that provide resistance to the flow of hydraulic oil that flows back and forth between the extension side chambers RR1 and LR1 and the outside of the cylinder 2 is the leaf valve 40, the notch leaf valve 36, and the like. A non-return valve 37 is used. When the damping valves 5 and 7 are throttles or chokes, the notch leaf valve 36, the leaf valve 40 and the non-return valve 37 can be eliminated and the expansion side port 3c and the pressure side port 3d can be used as they are as a throttle or choke. This may be realized by employing other configurations. Further, when it is desired to provide resistance only to the flow of hydraulic fluid from the extension side chambers RR1 and LR1 to the outside of the cylinder 2, the notch leaf valve 36 may be eliminated, and the hydraulic fluid from the outside of the cylinder 2 to the extension side chambers RR1 and LR1. When it is desired to give resistance only to the flow of the water, the leaf valve 40 may be eliminated and a non-return valve may be provided. Furthermore, if it is desired to eliminate the damping valves 5 and 7, the notched leaf valve 36, the leaf valve 40 and the non-return valve 37 may be eliminated.

  Subsequently, as shown in FIG. 7, the partition member 50 is provided in a disc-like main body 50a, a flange 50b provided at the lower end on the outer periphery side of the main body 50a, and a lower end in FIG. 7 of the main body 50a. A recess 50c, an insertion hole 50d through which a rod 53, which is provided in the shaft core of the main body 50a and which fixes the inner periphery of the leaf valve 51 and the non-return valve 52 described later, is inserted, and the main body 50a in FIG. An annular valve that is formed on the outer peripheral side of the window 50g that serves as the outlet end of the pressure side port 50f, the expansion side port 50e, the pressure side port 50f that communicates the upper surface and the recess 50c, and protrudes toward the leaf valve 51 from the bottom surface of the recess 50c. The main body 50 a is fitted to the inner periphery of the cylinder 2, and the flange portion 50 b is sandwiched between the cylinder 2 and the lower cap 59 and fixed to the cylinder 2.

  In this way, the partition member 50 is fixed to the lower end of the cylinder 2 to partition the pressure side chambers RR2 and LR2 in the cylinder 2 and the annular gap 56 between the cylinder 2 and the outer cylinder 55. Communication between the recess 50c and the annular gap 56 is ensured by the notch 50i provided in 50b, and the pressure side chambers RR2, LR2 and the annular gap 56 are communicated via the ports 50e, 50f formed in the partition member 50. ing.

  Then, a leaf valve 51 is laminated on the lower surface of the main body 50a of the partition member 50 in FIG. 7, and this leaf valve 51 is constituted by laminating a plurality of annularly formed leaves. 53, and is seated on the valve seat 50h to close the pressure side port 50f. On the other hand, a non-return valve 52 is laminated on the upper surface in FIG. 7 of the main body 50a of the partition member 50. The non-return valve 52 is fixed to the rod 53 on the inner peripheral side and closes the extension side port 50e.

  Here, when the fluid pressure dampers D1 and D2 expand and contract during vehicle travel and the volume of the pressure side chambers RR2 and LR2 increases or decreases, if there is no flow of hydraulic oil through the communication path 35, the inside of the pressure side chambers RR2 and LR2 Therefore, the hydraulic fluid that becomes excessive and insufficient flows in and out through the annular gap 56 between the cylinder 2 and the outer cylinder 55. When the volumes in the pressure side chambers RR2 and LR2 decrease, the expansion side port 50e is closed by the non-return valve 52, so that the hydraulic oil pushes open the leaf valve 51 and passes through the pressure side port 50f. Then, it is discharged out of the cylinder 2 through the annular gap 56. When this hydraulic oil passes through the pressure side port 50f, the leaf valve 51 provides resistance to the flow of the hydraulic oil.

On the other hand, when the volume in the pressure side chambers RR2 and LR2 increases, the pressure side port 50f is closed by the leaf valve 51, so that the hydraulic oil passes through the annular gap 56 from the outside of the cylinder 2, and further, The return valve 52 is pushed open, passes through the expansion side port 50e, and is supplied into the pressure side chambers RR2 and LR2.

  In the present embodiment, the leaf valve 51 is configured to correspond to the damping valves 6 and 8 that provide resistance to the flow of hydraulic fluid that flows out of the cylinder 2 from the pressure side chambers RR2 and LR2. When the damping valves 6 and 8 are used as choke or choke, the leaf valve 51 and the non-return valve 52 may be eliminated and the expansion side port 50e and the pressure side port 50f may be used as they are as choke or choke. This may be realized by adopting a configuration. In addition, when it is desired to give resistance to the flow of hydraulic fluid from the outside of the cylinder 2 toward the pressure side chambers RR2 and LR2, a leaf valve that opens and closes the expansion side port 50e may be provided in the partition member 50. If it is desired to eliminate the damping valves 6 and 8, the leaf valve 51 and the non-return valve 52 may be eliminated.

  And each fluid pressure damper D1, D2 is connected by the 1st flow path P1 and the 2nd flow path P2, and specifically, the 1st flow path P1 is opening of the upper end of piston rod 4 of one fluid pressure damper D1. And the opening 55a provided at the lower end of the outer cylinder 55 of the other fluid pressure damper D2, and the second flow path P2 includes an opening 55a provided at the lower end of the outer cylinder 55 of the one fluid pressure damper D1, The other fluid pressure damper D2 is connected to the opening at the upper end of the piston rod 4.

  That is, the first flow path P1 is connected to the expansion chamber RR1 of one fluid pressure damper D1 through an annular gap 56 between the piston rod 4 of the fluid pressure damper D1 and the cylinder 2 and the outer cylinder 55 of the fluid pressure damper D2. And the pressure side chamber LR2 of the other fluid pressure damper D2, and the other second flow path P2 is formed between the piston rod 4 of the fluid pressure damper D2, the cylinder 2 of the fluid pressure damper D1, and the outer cylinder 55. A pressure side chamber RR2 of one fluid pressure damper D1 and an extension side chamber LR1 of the other fluid pressure damper D2 are connected via an annular gap 56 therebetween.

  The first accumulator A1 includes a hollow housing 60 connected to the outer cylinder 55 of the fluid pressure damper D2, and a free piston 61 that is slidably inserted into the housing 60 to partition the air chamber G and the fluid chamber r. A partition member 62 that partitions between the fluid chamber r and the annular gap 56; a damping valve 63 as a first valve element V1 provided in the partition member 62 and providing resistance to the flow of fluid flowing into and out of the fluid chamber r; It has.

  As shown in FIG. 8, the housing 60 includes a hollow main body 60a, and a hollow connecting portion 60b connected to the lower end side in FIG. 8 of the main body 60a and the lower end in FIG. Is communicated with the annular gap 56 of the fluid pressure damper D1. The main body 60a is composed of two upper and lower cylinders in order to simplify the processing in the drawing, but it goes without saying that these may be integrated into one cylinder.

  Then, as described above, the free piston 61 is slidably inserted into the main body 60a, the inside of the main body 60a is partitioned into an air chamber G and a fluid chamber r, and further inside the lower end side of the main body 60a. The fluid chamber r and the annular gap 56 are partitioned by the fixed partition member 62. Further, the partition member 62 includes a supply port 62a and a discharge port 62b communicating with the fluid chamber r and the annular gap 56, and the supply port 62a is an annular member stacked on the upper surface of the partition member 62 in FIG. The other discharge port 62b is closed by an annular leaf valve 65 stacked on the lower surface of the partition member 62 in FIG.

  Accordingly, the first connection path J1 includes the annular gap 56 that communicates with the first flow path P1, the connecting portion 60b, the supply port 62a, and the discharge port 62b. When hydraulic fluid is supplied from the annular gap 56 into the fluid chamber r, the hydraulic fluid passes through the supply port 62a by pushing the leaf valve 64 open because the discharge port 62b is closed by the leaf valve 65. Into the fluid chamber r. On the other hand, when the hydraulic oil is discharged from the fluid chamber r to the annular gap 56, the supply port 62a is closed by the leaf valve 64, so the hydraulic oil passes through the discharge port 62b by pushing the leaf valve 65 open. It flows out into the annular gap 56.

  When the hydraulic oil flows into the fluid chamber r, the leaf valve 64 gives resistance to the flow of the hydraulic oil, and when discharged from the fluid chamber r, the leaf valve 65 is In the present embodiment, the damping valve 63 as the first valve element V1 provided to the partition member 62 is configured with leaf valves 64 and 65.

  The free piston 61 is provided with a recess 61a at the lower end in FIG. 8. Even if the lower surface of the outer periphery of the free piston 61 comes into contact with the outer periphery of the upper end of the partition member 62, the recess 61a The first damping force variable mechanism C1 provided at the tip of the rod 66 that fixes the leaf valve 64 and the leaf valves 64 and 65 to the partition member 62 is set to be accommodated in the 61a without interfering with the free piston 61. May be. The rod 66 is cylindrical and is screwed to the connecting portion 60b, and the inside is communicated with the first flow path P1 via the connecting portion 60b.

  Although the 1st accumulator A1 and the 1st valve element V1 accommodated in this 1st accumulator A1 are comprised as mentioned above, the 2nd accumulator A2 is also set as the structure similar to above-mentioned 1st accumulator A1. At the same time, the second valve element V2 has the same configuration as the first valve element V1 and is accommodated in the second accumulator A2. The second accumulator A2 is connected to the side of the outer cylinder 55 of the fluid pressure damper D1. Has been.

  Next, the first damping force variable mechanism C1 will be described. As shown in FIG. 8, the first damping force variable mechanism C1 includes a sub cylinder 70 as a first sub cylinder, a free piston 73 as a first free piston slidably inserted into the sub cylinder 70, The free piston 73 is positioned in a neutral position within the sub-cylinder 70 and includes coil springs 74 and 75 as first spring elements that exert a biasing force that suppresses displacement from the neutral position. By attaching the cylinder 70 to the rod 66, it is fixed while being accommodated in the first accumulator A1.

  The sub-cylinder 70 includes a lid member 71 that is screwed to the rod 66, and a cap-like cylindrical sub that accommodates the lid member 71 inside and is integrated with the outer periphery of a flange 71b provided on the outer periphery of the lid member 71. A cylinder main body 72 is provided.

  The lid member 71 includes a cylindrical nut 71a attached to the outer periphery of the rod 66 on the inner periphery, and a flange 71b provided on the outer periphery of the nut 71a. Then, by screwing the nut 71a in the lid member 71 to the rod 66, the partition member 62 and the leaf valves 64, 65 and the like stacked thereon can be fixed to the rod 66 as described above. The sub cylinder 70 can be fixed to the rod 66. The rod 66 has a cylindrical shape, and the inside of the sub-cylinder 70 is communicated with the first flow path P <b> 1 through the inside of the rod 66.

  The sub-cylinder main body 72 includes a cylindrical portion 72a and a top portion 72b that closes the upper end of the cylindrical portion 72a in FIG. The cylinder portion 72a is provided with an orifice 72c communicating with the inside and outside of the sub cylinder 70, and the top portion 72b is provided with an orifice 72d communicating with the inside and outside of the sub cylinder 70.

  And after accommodating the cover member 71 in the sub-cylinder main body 72, the open end of the cylinder part 72a is crimped toward the outer periphery of the said flange 71b from an outer peripheral side, and the cover member 71 and the sub-cylinder main body 72 are carried out. Integrated. In addition, when integrating the lid member 71 and the sub-cylinder main body 72, it is also possible to employ other methods such as welding in addition to the caulking process.

  In the sub-cylinder main body 72 in this example, since the thickness on the upper side in FIG. 8 of the cylindrical portion 72a is thick, the cross-sectional shape of the outer periphery of this part is a shape other than a perfect circle, for example, a part A shape such as a notch or a hexagonal shape can be formed, and a tool is engaged with this portion so that the sub-cylinder 70 is screwed to the tip of the rod 66.

  A free piston 73 is slidably inserted into the sub-cylinder 70 formed as described above, and the sub-cylinder 70 is a lower pressure chamber as a first flow path side pressure chamber on the lower side in FIG. 77 and an upper pressure chamber 76 as an upper first accumulator side pressure chamber.

  The free piston 73 is formed in a cylindrical shape with a top, a cylindrical portion 73a, a top portion 73b that closes the upper end in FIG. 8 of the cylindrical portion 73a, and an annular groove 73c provided on the outer periphery of the cylindrical portion 73a along the circumferential direction. And a through hole 73d that opens from the outer periphery of the top 73b in FIG. 8 and communicates with the annular groove 73c.

The free piston 73 is inserted into the sub-cylinder 70 with the outer periphery of the cylindrical portion 73 a in sliding contact with the inner periphery of the cylindrical portion 72 a of the sub-cylinder main body 72. A pair of coil springs 74 and 75 as spring elements for applying an urging force that suppresses displacement with respect to the free piston 73 is accommodated in the sub-cylinder 70.

  The coil spring 75 is interposed in the lower pressure chamber 77 between the flange 71b of the lid member 71 and the top 73b of the free piston 73. The coil spring 74 is the upper pressure chamber 76 and the sub cylinder body 72. Between the top portion 72b of the free piston 73 and the top portion 73b of the free piston 73.

  As described above, the free piston 73 is sandwiched from above and below by the first spring elements formed by the coil springs 74 and 75 and is elastically supported after being positioned at a predetermined neutral position in the sub cylinder 70.

As the first spring element, it is only necessary that the free piston 73 can be elastically supported, so that a member other than the coil springs 74 and 75 may be employed. For example, the free piston 73 may be formed using an elastic body such as rubber or a disc spring. May be elastically supported. In the case of using a single elastic member one end of which is connected to the free piston 73 may be fixed at the other end to the lid member 71 or the sub-cylinder 70.

  The lower pressure chamber 77 is connected to the first flow path P <b> 1 through the rod 66. In this case, an orifice is not provided between the lower pressure chamber 77 and the first flow path P1, but an orifice may be provided in the rod 66 or the like.

  The upper pressure chamber 76 communicates with the fluid chamber r of the first accumulator A1 through an orifice 72d provided in the sub cylinder body 72. When the free piston 73 is in the neutral position, the cylinder portion 73a An annular groove 73c provided on the outer periphery of the sub-cylinder body 72 is communicated with the fluid chamber r by a through-hole 73d, an annular groove 73c and an orifice 72c so as to face the orifice 72c provided in the sub cylinder body 72. Therefore, an orifice 72c and an orifice 72d are provided between the upper pressure chamber 76 and the first accumulator A1.

  Then, when the free piston 73 is displaced from the neutral position and displaced upward or downward in FIG. 8, the degree of lap between the orifice 72c and the annular groove 73c gradually decreases as the displacement progresses, and the free piston 73 eventually becomes free. When displaced to the vicinity of the stroke end, the orifice 72c does not face the annular groove 73c and is closed by the cylindrical portion 73a. In this state, the upper pressure chamber 76 communicates with the first accumulator A1 only by the orifice 72d. Will be. Therefore, the orifice 72c functions as a variable orifice that changes the flow path area by displacement from the neutral position of the free piston 73, and when the displacement amount from the neutral position of the free piston 73 increases and the flow path area begins to decrease. Further, the displacement of the free piston 73 toward the stroke end side can be suppressed.

  Thus, the first damping force variable mechanism C1 is configured, and the second damping force variable mechanism C2 is also configured by the same member as the first damping force variable mechanism C1 and is accommodated in the second accumulator A2. .

As described above, even in the suspension device S1 having a specific configuration, the first damping force variable mechanism C1 and the second damping force variable mechanism C2 serve as apparent flow paths when the free piston 73 is displaced. Therefore, the same function and effect as the suspension device S1 of the embodiment shown in FIG. 1 can be achieved, and the first damping force variable mechanism C1 and the first valve element V1 are placed in the first accumulator A1. Since the second damping force variable mechanism C2 and the second valve element V2 are accommodated in the second accumulator A2, the mountability on the vehicle is improved.

  Further, the second accumulator A2 containing the second damping force variable mechanism C2 and the second valve element V2 is integrated with the fluid pressure damper D1, and the first damping force variable mechanism C1 and the first valve element are integrated with the fluid pressure damper D2. Since the first accumulator A1 containing V1 is integrated, the suspension device S1 can be formed simply by connecting the fluid pressure dampers D1 and D2 with the first flow path P1 and the second flow path P2. Installation on the vehicle is very easy.

  Furthermore, when each of the fluid pressure dampers D1 and D2 expands and contracts, an oil film is formed on the sliding surface that is in sliding contact with the cylinder 2 of the piston band 3k attached to the outer periphery of the piston 3. Varies with sliding speed and other factors. Therefore, when each of the fluid pressure dampers D1, D2 repeats expansion and contraction over a long period of time, the hydraulic oil moves back and forth between the piston band 3k attached to the outer periphery of the piston 3 and the cylinder 2, but the extension side chambers RR1, LR1. The balance between the amount of hydraulic fluid that moves from the pressure side chambers RR2 and LR2 to the amount of hydraulic fluid that moves from the pressure side chambers RR2 and LR2 to the extension side chambers RR1 and LR1 is not balanced, and the free piston 61 of the accumulators A1 and A2 is not in the housing 60. Although there may be a situation where the positions differ greatly from each other, in this embodiment, since the permeation circulation member 33 is provided in the middle of the communication path 35, the vehicle is stopped for a long time and the vehicle body is suspended by the suspension spring. Is supported and balanced, between the extension side chambers RR1, LR1 and the pressure side chambers RR2, LR2 through the permeation flow member 33. Since very slowly working oil over a long time it comes to traverse, in the end it is possible to balance the pressure of the expansion side chamber RR1, LR1 and the compression side chamber RR2, LR2. Thus, by correcting the pressures of the expansion chambers RR1, LR1 and the compression chambers RR2, LR2 so that the positions of the free pistons 61 with respect to the housing 60 of the accumulators A1, A2 are substantially the same, The pressure in each accumulator A1, A2 can be made substantially the same, and the suspension device S1 exhibits a damping force and a spring reaction force that are different from each other in the fluid pressure dampers D1, D2 with respect to the roll direction of the vehicle body. There is no invitation.

  In this embodiment, the permeation flow member 33 is provided in each of the fluid pressure dampers D1 and D2, but the communication path 35 is provided only in one of the fluid pressure dampers D1 (D2). Alternatively, the permeation flow member 33 may be provided, or a communication path is provided so as to directly connect the first flow path P1 and the second flow path P2, thereby extending the extension chamber RR1 of the fluid pressure dampers D1 and D2. , LR1 and the pressure side chambers RR2, LR2 may be communicated, and an osmotic flow member may be provided in the middle of the communication path.

  Next, the suspension device S2 of the second embodiment will be described. As shown in FIG. 9, the suspension device S2 of the second embodiment is different from the suspension device S1 of the first embodiment in that the first damping force variable mechanism C3, the second damping force variable mechanism C4, The configurations of the one valve element V3 and the second valve element V4 are different, and the other configurations have the same configuration as the suspension device S1 of the first embodiment.

  Therefore, in the description of the suspension device S2 of the second embodiment, the description of the same configuration as the suspension device S1 of the first embodiment will be repeated, so only the same reference numerals will be given, and only the different configuration will be described in detail. And The same applies to the description of the third embodiment to be described later.

  The first valve element V3 in the suspension device S2 of the second embodiment is a variable damping valve, and the flow path area is variable depending on the displacement amount of the first free piston 81 of the first damping force variable mechanism C3. It is supposed to be. Similarly, the second valve element V4 is also a variable damping valve, and the flow path area is made variable depending on the amount of displacement of the second free piston 91 of the second damping force variable mechanism C4.

  The first damping force variable mechanism C3 includes a first sub cylinder 80 connected to the first flow path P1, a first free piston 81 slidably inserted into the first sub cylinder 80, and a first free piston 81. The first flow path side pressure chamber 82 and the first accumulator side pressure chamber 83 and the first free piston 81 partitioned in the first sub cylinder 80 are positioned in a neutral position with respect to the first sub cylinder 80 and the first free cylinder A first spring element 84 that exerts an urging force that suppresses displacement from the neutral position of the piston 81; an orifice 86 provided in the middle of the flow path 85 that connects the first flow path side pressure chamber 82 to the first flow path P1; The first free piston 81 includes an orifice 88 provided in the middle of a flow path 87 connecting the one accumulator side pressure chamber 83 to the first accumulator A1. The flow passage area of the first valve element V3 is adapted to become smaller as the displacement amount from the neutral position increases.

  The second damping force variable mechanism C4 includes a second sub cylinder 90 connected to the second flow path P2, a second free piston 91 slidably inserted into the second sub cylinder 90, and a second free piston. The second flow path side pressure chamber 92 and the second accumulator side pressure chamber 93 and the second free piston 91 partitioned in the second sub cylinder 90 at 91 are positioned to the neutral position with respect to the second sub cylinder 90 and A second spring element 94 that exerts an urging force that suppresses displacement from the neutral position of the two free pistons 91, and an orifice provided in the middle of the flow path 95 that connects the second flow path side pressure chamber 92 to the second flow path P2. 96 and an orifice 98 provided in the middle of a flow path 97 connecting the second accumulator side pressure chamber 93 to the second accumulator A2, and a second free piston 91. The flow passage area of the second valve element V4 is adapted to become smaller as the displacement amount from the neutral position increases.

  As described above, the suspension device S2 is configured, and in the first damping force variable mechanism C3 in this example, the orifices 86 and 88 that cause a first-order lag in pressure propagation are provided. When the pressure alternates at a high frequency on the first flow path P1 side, it becomes difficult to transmit the pressure on the first flow path P1 side to the first flow path side pressure chamber 82. In such a situation, the first free piston 81 is moved from the neutral position. Since it becomes difficult to displace, the flow path area in the first valve element V3 is maintained in a large state. On the other hand, when the frequency of the alternating pressure on the first flow path P1 side is a low frequency, the pressure on the first flow path P1 side is transmitted to the first flow path side pressure chamber 82, and the first free piston 81 is greatly increased from the neutral position. As a result, the flow path area of the first valve element V3 is reduced.

  Similarly, in the second damping force variable mechanism C4, since the orifices 96 and 98 that cause a first-order lag in pressure propagation are provided, the pressure is alternated at a high frequency on the second flow path P2 side. The pressure on the second flow path P2 side is less likely to be transmitted to the second flow path side pressure chamber 92. In such a situation, the second free piston 91 is less likely to be displaced from the neutral position. The flow path area is maintained in a large state. On the other hand, when the frequency of the alternating pressure on the second flow path P2 side is a low frequency, the pressure on the second flow path P2 side is transmitted to the second flow path side pressure chamber 92, and the second free piston 91 is neutral. The position is greatly displaced from the position, and the flow path area in the second valve element V4 is reduced.

  Therefore, when high frequency vibration is input to each of the fluid pressure dampers D1 and D2, the frequency of the alternating pressure in the first flow path P1 and the second flow path P2 also increases, and the first free piston 81 and the second free piston 91 are neutral. The amount of displacement from the position is reduced, and the flow path areas of the first valve element V3 and the second valve element V4 are maintained large. Therefore, the resistance that the first valve element V3 gives to the flow of hydraulic fluid going back and forth between the first actuator A1 and the first flow path P1 is small, and the second valve element V4 goes back and forth between the second actuator A2 and the second flow path P2. Since the resistance given to the flow of oil becomes small, the damping force generated by each fluid pressure damper D1, D2 becomes low.

  Conversely, when low frequency vibration is input to each of the fluid pressure dampers D1 and D2, the frequency of the alternating pressure in the first flow path P1 and the second flow path P2 also decreases, and the first free piston 81 and the second free piston 91. The amount of displacement from the neutral position increases, and the flow path areas of the first valve element V3 and the second valve element V4 decrease. Therefore, the resistance that the first valve element V3 gives to the flow of the hydraulic oil going back and forth between the first actuator A1 and the first flow path P1 is large, and the second valve element V4 goes back and forth between the second actuator A2 and the second flow path P2. Since the resistance given to the oil flow increases, the damping force generated by each of the fluid pressure dampers D1, D2 increases.

  As described above, according to the suspension device S2 of the second embodiment, when vibrations in a low frequency range are input to the fluid pressure dampers D1 and D2, the first valve element V3 and the second valve element V4. When the resistance given to the flow of hydraulic fluid passing through is increased to increase the damping force generated by the fluid pressure dampers D1 and D2, and vibrations in a high frequency range are input to the fluid pressure dampers D1 and D2. Can reduce the resistance given to the flow of hydraulic fluid through which the first valve element V3 and the second valve element V4 pass, and reduce the damping force generated by each fluid pressure damper D1, D2.

  Therefore, even in the suspension device S2 in the second embodiment, as in the suspension device S1 in the first embodiment, in the situation where the vehicle turns and the vehicle body rolls, each fluid pressure damper D1, D2 is a scene in which the damping force can be increased to suppress the rolling, and only one wheel gets over the road surface unevenness or passes through the bumpy road, and high frequency vibration is input. In a situation where the dampers D1 and D2 are out of phase or only one of them is expanded and contracted at a high speed, it is possible to reduce the damping force and improve the riding comfort in the vehicle.

  It should be noted that the first damping force variable mechanism C3 and the second damping force variable mechanism C4 perform their functions even when the fluid pressure dampers D1 and D2 expand and contract in the same phase, but the fluid pressure dampers D1 and D2 Are expanded and contracted in the same phase, the amount of hydraulic fluid exchanged by the fluid pressure dampers D1 and D2 with the first accumulator A1 and the second accumulator A2 is expanded and contracted by the fluid pressure dampers D1 and D2. Less than the case. Therefore, when the fluid pressure dampers D1 and D2 expand and contract in the same phase, the flow path areas of the first valve element V3 and the second valve element V4 are maintained larger than in the opposite phase. Since the damping force generated by each of the fluid pressure dampers D1 and D2 when the dampers D1 and D2 expand and contract in the same phase does not become too high, a good riding comfort can be ensured.

  In this embodiment, either one of the orifices 86 and 88 and one of the orifices 96 and 98 can be eliminated. Similarly to the suspension device S1 of the first embodiment, as shown by the broken lines in FIG. 9, the suspension is operated from the first sub cylinder 80 and the second sub cylinder 90 in parallel with the orifices 86, 88, 96, 98. The check valves W, X, Y, and Z that allow only the flow in the direction of discharging the oil are provided, and the orifice 86, only when the hydraulic oil flows into the first sub cylinder 80 and the second sub cylinder 90, It is also possible for 88, 96, 98 to function. Also in this case, an orifice that functions according to the direction of displacement from the neutral position of the first free piston 81 and the second free piston 91 can be selected, and the displacement characteristics of the first free piston 81 and the second free piston 91 can be selected. For example, the damping force characteristics on the expansion side and the compression side when the fluid pressure dampers D1 and D2 expand and contract in the same phase can be set individually.

  Further, by providing the first spring element 84 in the first damping force variable mechanism C3 and the second spring element 94 in the second damping force variable mechanism C4, even if the first free piston 81 and the second free piston 91 are displaced. It is possible to return to the neutral position, and at the time of high-frequency vibration input, it is possible to reliably increase the flow passage areas of the first valve element V3 and the second valve element V4 and to reliably obtain the damping force reduction effect.

  Note that the flow path area of the first valve element V3 may be set linearly with respect to the displacement from the neutral position of the first free piston 81, or from the neutral position of the first free piston 81. It is also possible to set so that the flow path area of the first valve element V3 starts to decrease when the displacement of the second free piston 91 exceeds a predetermined amount. The flow path area of the valve element V4 may be set to be small, or when the displacement from the neutral position of the second free piston 91 exceeds a predetermined amount, the flow path area of the second valve element V4 becomes small. It can also set so that it may start, and these settings can be arbitrarily set according to the characteristic of the damping force generated in each fluid pressure damper D1, D2.

Furthermore, as in the suspension device S3 of a modification of the second embodiment shown in FIG. 10, a check valve 100 is provided to move the first valve element V3 from the first flow path P1 to the first actuator A1 side. The flow is set so as to give resistance only to the flow of hydraulic oil that goes to it, and resistance is given to the flow of hydraulic oil that goes from the first accumulator A1 to the first flow path P1 in parallel with the first valve element V3 in the first connection path J1. The first discharge side valve element Vp1 and the check valve 101 are provided, and further, the check valve 102 is provided to resist the second valve element V4 only to the flow of hydraulic oil from the second flow path P2 toward the second actuator A2. The second discharge side valve element Vp2 that provides resistance to the flow of hydraulic fluid from the second accumulator A2 to the second flow path P2 in parallel with the second valve element V4 in the second connection path J2 And check valve 103 It is also possible to so that. When the first valve element V3, the second valve element V4, the first discharge side valve element Vp1 and the second discharge side valve element Vp2 are one-way valves that only allow the hydraulic oil to flow in one direction. Can omit the check valves 100, 101, 102, 103 arranged in series corresponding to the valve elements V3, V4, Vp1, Vp2.

  In the suspension device S3 of the modified example configured as described above, the first damping force variable mechanism C3 changes the flow path area of the first valve element V3 in a situation where hydraulic fluid flows from the first flow path P1 to the first actuator A1. By making the damping force variable, the second damping force variable mechanism C4 changes the flow path area of the second valve element V4 in a situation where hydraulic fluid flows from the second flow path P2 to the second actuator A2. Make the damping force variable.

  In the suspension device S3, when the fluid pressure dampers D1 and D2 expand or contract in opposite phases as described above or only one of them expands or contracts, the hydraulic oil is always pushed out from the high-pressure side chamber to be compressed. One of the first and second accumulators A1 and A2 flows into one of the corresponding accumulators.

  Therefore, the damping force is made variable by changing the flow path area of the first valve element V3 only in a situation where the hydraulic fluid flows from the first flow path P1 to the first actuator A1 in the first damping force variable mechanism C3. Adopting a configuration in which the damping force is made variable by changing the flow path area of the second valve element V4 only when the hydraulic fluid flows from the second flow path P2 to the second actuator A2 in the variable damping force mechanism C4. However, when the fluid pressure dampers D1 and D2 expand or contract in opposite phases or only one of them expands or contracts, the damping force can be increased when low frequency vibration is input, and the damping force is reduced when high frequency vibration is input. Demonstrate. As described above, even in the suspension device S3 of the present embodiment, the flow area of the first valve element V3 or the second valve element V4 becomes large at the time of high-frequency vibration input while suppressing rolling of the vehicle body. Accordingly, the damping force generated by each of the fluid pressure dampers D1 and D2 is reduced, and the damping force can be exerted according to the basic operation without exhibiting the damping force reduction effect for the input of the low frequency vibration.

  In order to specifically configure the suspension device S3 according to a modification of the second embodiment, it may be configured as shown in FIG. A specific suspension device S3 is different from the specific suspension device S1 shown in FIG. 5 in that a first damping force variable mechanism C3, a second damping force variable mechanism C4, a first valve element, as shown in FIG. The configurations of V3 and the second valve element V4 are different, and the other configurations have the same configuration as the suspension device S1 of the first embodiment. The first damping force variable mechanism C3 and the first valve element V3 are accommodated in the first accumulator A1, and the second damping force variable mechanism C4 and the second valve element V4 are accommodated in the second accumulator A2. The variable mechanism C3 and the second damping force variable mechanism C4 are composed of the same member, and the first valve element V3 and the second valve element V4 are also composed of the same member. Accordingly, the fluid pressure dampers D1 and D2 are not shown, and only the portions different from the suspension device S1 will be described in detail.

  As shown in FIG. 11, the first damping force variable mechanism C3 (second damping force variable mechanism C4) is integrated with the first valve element V3 (second valve element V4) to form a damping force variable unit U. ing. Specifically, the first damping force variable mechanism C3 (second damping force variable mechanism C4) is slidably inserted into the sub cylinder 110 as the first sub cylinder (second sub cylinder) and the sub cylinder 110. A free piston 111 as a first free piston (second free piston) and a first spring element that positions the free piston 111 in a neutral position within the sub-cylinder 110 and exerts an urging force that suppresses displacement from the neutral position An annular spring 112 as a (second spring element) is provided, and is attached to the rod 66 by a housing cylinder 113 that houses these components.

  The sub-cylinder 110 includes a bottomed cylindrical housing 114 having a hole at the bottom, an annular guide member 115 fitted to the opening end of the housing 114, and a spring receiving member 116 accommodated in the housing 114. Configured.

  The guide member 115 has an annular shape, and a step portion is formed on the outer periphery. The lower side in FIG. 11 has a small diameter, and the small diameter portion is fitted to the opening end of the housing 114. A step portion 115 a is also formed on the inner periphery of the guide member 115. Further, the guide member 115 is provided with a port 115b that penetrates the guide member 115 up and down.

  The spring receiving member 116 includes an annular protrusion 116a provided at the upper end, an orifice 116b opening from the lower end in FIG. 11 to the inner peripheral side of the upper annular protrusion 116a, and an annular protrusion 116a at the upper end from the lower end in FIG. And a port 116c that opens to the outer peripheral side.

  The free piston 111 has a flange 111a on the outer periphery, and is slidably inserted into the inner periphery of the guide member 115. When the free piston 111 is displaced upward in FIG. 11, the flange 111 a finally comes into contact with the step portion 115 a of the guide member 115, so that it cannot be removed from the guide member 115 any more. It has become.

  Further, a connector 117 having a perforated disc-shaped annular spring 112 attached to the outer periphery is attached to the center of the free piston 111, and the annular spring 112 is integrated with the free piston 111.

  The outer periphery of the annular spring 112 is sandwiched between the guide member 115 and the annular protrusion 116a of the spring receiving member 116, and the annular spring 112 is allowed to bend on the inner peripheral side. Therefore, when the free piston 111 is displaced in the axial direction with respect to the guide member 115 from the neutral position, the annular spring 112 is deformed and exerts an urging force for returning the free piston 111 to the neutral position.

Further, since the spring receiving member 116 is fitted to the inner periphery of the housing 114 and the annular spring 112 is sandwiched between the free piston 111 and the guide member 115 into which the free piston 111 is slidably inserted, the free piston 111 and the spring A chamber 120 as a first flow path side pressure chamber (second flow path side pressure chamber) is formed between the receiving member 116 and the receiving member 116. Further, the space 121 above the free piston 111 in FIG. 11 is communicated with the fluid chamber r of the first accumulator A1 (second accumulator A2). That is, the sub cylinder 110 is partitioned by the free piston 111 into a first flow path side pressure chamber (second flow path side pressure chamber) and a first accumulator side pressure chamber (second accumulator side pressure chamber) .

  Subsequently, the diameter of the upper end side of the accommodation cylinder 113 in FIG. 11 is increased, and the insertion of the sub cylinder 110 can be permitted. Specifically, the housing cylinder 113 includes a cylindrical screw portion 113a that is screwed to the rod 66, and a cylindrical housing portion 113b that is larger in diameter than the screw portion 113a provided at the upper end of the screw portion 113a. Yes.

  The lower end of the storage cylinder 113 is set to a diameter that does not block the discharge port 62b of the partition member 62. When the storage cylinder 113 is screwed to the rod 66, the leaf that opens and closes the partition member 62 and the discharge port 62b. The valve 65 can be fixed to the connecting portion 60b.

  In the accommodating portion 113b of the accommodating cylinder 113, a washer-shaped spacer 122, a housing 114, a spring receiving member 116, a free piston 111 integrated with the annular spring 112, and a guide member 115 are accommodated in this order. In the upper part of the member 115 in FIG. 11, a leaf valve 118 which is an annular and set to be inwardly opened as the first valve element V3 (second valve element V4), and the outer periphery of the leaf valve 118 is guided by the guide member 115. By laminating an annular valve holding member 119 to be sandwiched and caulking the upper end opening end in FIG. 11 of the housing cylinder 113, each member housed in the housing cylinder 113 is the housing cylinder except for the free piston 111. It is fixed in 113.

  The leaf valve 118 has an inner periphery at the lower end in FIG. 11 that is in contact with an outer periphery at the upper end in FIG. 11 of the free piston 111, and shuts off the port 115 b provided in the guide member 115 in the state of contact with the free piston 111. ing. Further, the leaf valve 118 is sandwiched between the annular protrusion 119a provided at the lower end of the valve holding member 119 and the upper end of the guide member 115, and the leaf valve 118 is allowed to bend upward in FIG. When it is separated from the free piston 111 by bending, the port 115b is opened. Then, when the free piston 111 is displaced upward in FIG. 11 while bending the annular spring 112, the leaf valve 118 is pushed up on the outer periphery of the free piston 111 so that the initial deflection of the leaf valve 118 is increased. The valve opening pressure of the valve 118 can be made variable. Thus, in order to increase the resistance given to the flow of hydraulic oil in the first valve element V3 (second valve element V4), the flow path area of the first valve element V3 (second valve element V4) described above is increased. In addition to decreasing, increasing the valve opening pressure of the first valve element V3 (second valve element V4) is also included.

  The port 115 b communicates with the rod 66 through a port 116 c provided in the spring receiving member 116. Since the inside of the rod 66 communicates with the first flow path P1 (second flow path P2), the port 115b communicates with the first flow path P1 (second flow path P2).

  Therefore, when the leaf valve 118 is bent and the port 115b is opened, hydraulic oil is supplied from the first flow path P1 (second flow path P2) side to the first accumulator A1 (second accumulator A2) through the port 115b and the rod 66. Become so.

  When the pressure in the chamber 120 as the first flow path side pressure chamber increases and the free piston 111 is displaced upward in FIG. 11 while bending the annular spring 112, the leaf valve 118 is pushed up on the outer periphery of the free piston 111. The initial deflection of the leaf valve 118 increases, and the valve opening pressure of the leaf valve 118 increases.

  Since the chamber 120 communicates with the first flow path P1 (second flow path P2) through the orifice 116b and the rod 66, the pressure on the first flow path P1 (second flow path P2) side propagates with a first order lag. It is like that. Therefore, when the frequency of the pressure alternation on the first flow path P1 (second flow path P2) side is high, it becomes difficult to transmit pressure to the chamber 120 as the first flow path side pressure chamber (second flow path side pressure chamber), and the free piston Even if 111 is displaced upward from the neutral position shown in FIG. 11, the amount of displacement is very small, and the initial load of the leaf valve 118 as the first valve element V3 (second valve element V4) is small. The resistance given to the hydraulic fluid that the leaf valve 118 passes from the first flow path P1 (second flow path P2) to the first accumulator A1 (second accumulator A2) is small, and the fluid pressure dampers D1 and D2 are in reverse phase. The damping force generated by each of the fluid pressure dampers D1 and D2 when expanding or contracting at the time or when only one of them expands or contracts becomes small. On the other hand, when the frequency of the pressure alternation on the first flow path P1 (second flow path P2) side is low, the pressure propagates to the chamber 120 as the first flow path side pressure chamber (second flow path side pressure chamber), and the free piston 111 11 is pushed upward from the neutral position shown in FIG. 11 to bend the leaf valve 118 as the first valve element V3 (second valve element V4), so that the initial load of the leaf valve 118 is increased. In this state, the resistance given to the hydraulic oil that the leaf valve 118 passes from the first flow path P1 (second flow path P2) to the first accumulator A1 (second accumulator A2) increases, so that each fluid pressure damper D1, D2 The damping force generated by each of the fluid pressure dampers D1 and D2 when the cylinder expands and contracts in the opposite phase or when only one expands or contracts increases.

  Therefore, even in this specific suspension device S3, when the vehicle turns and the vehicle body rolls, each of the fluid pressure dampers D1 and D2 can suppress the rolling by increasing the damping force. In this situation, only the wheels get over the road surface irregularities or pass through the bumpy road, where high frequency vibration is input, and each fluid pressure damper D1 and D2 expands or contracts at high speed in reverse phase or only on one side. In the situation, the damping force can be reduced to improve the riding comfort in the vehicle.

  In the specific suspension device S3, the first damping force variable mechanism C3 and the first valve element V3 are accommodated in the first accumulator A1, and the second damping force variable mechanism C4 and the second valve element V4. Are accommodated in the second accumulator A2, the suspension device S3 can be formed simply by connecting the fluid pressure dampers D1 and D2 with the first flow path P1 and the second flow path P2, and is attached to the vehicle. Is very easy.

  Further, like the suspension device S4 of another modification of the second embodiment shown in FIG. 12, the first flow path P1 and the first accumulator A1 are connected by bypassing the first valve element V3. Sub-connection path JS1, fifth valve element V5 provided in first sub-connection path JS1 and capable of giving resistance to the flow of hydraulic fluid passing therethrough, and second flow path bypassing second valve element V4 A second sub-connection path JS2 that connects P2 and the second accumulator A2 and a sixth valve element V6 that is provided in the second sub-connection path JS2 and can provide resistance to the flow of hydraulic fluid passing therethrough are provided. It may be. In this case, the fifth valve element V5 always keeps the first flow path P1 and the first accumulator A1 in communication, and the sixth valve element V6 always keeps the second flow path P2 and the second accumulator A2 in communication. The first valve element V3 may be set to close the first connection path J1, and the second valve element V4 may be set to close the second connection path J2.

  Also, in each of the suspension devices S3 and S4 shown in FIGS. 10 and 12, check valves W, X, Y, and Z are provided in parallel with the orifices 86, 88, 96, and 98, similarly to the suspension devices S1 and S2. Of course, it may be possible to do so.

  In addition, in the suspension device S3 of the modified example of the second embodiment shown in FIG. 10, the first damping force is the same as the suspension device S5 of another modified example of the second embodiment shown in FIG. The first accumulator side pressure chamber 83 and the second accumulator side pressure chamber 93 of the variable mechanism C3 and the second damping force variable mechanism C4 are each a sealed space filled with gas, opened to the atmosphere, or the first accumulator A1. It is also possible to connect to the second accumulator A2 without resistance. In this case, the first free piston 81 can be displaced by supplying / discharging the hydraulic oil by the first sub cylinder 80 and the second free piston 91 can be displaced by supplying / discharging the hydraulic oil by the second sub cylinder 90. can do. In this case, the damping force can be varied by changing the flow path area of the first valve element V3 only when the hydraulic fluid flows from the first flow path P1 to the first actuator A1 in the first damping force variable mechanism C3. The damping force can be varied by changing the flow path area of the second valve element V4 only when the hydraulic fluid flows from the second flow path P2 to the second actuator A2 in the second damping force variable mechanism C4. Become. Even when such a configuration is adopted, in the suspension device S5, as described above, when the fluid pressure dampers D1 and D2 expand or contract in opposite phases, or only one of them expands or contracts, the high pressure side to be compressed is always used. Since hydraulic oil is pushed out of the chamber and flows into one of the corresponding accumulators of the first and second accumulators A1 and A2, the fluid pressure dampers D1 and D2 expand or contract in opposite phases, In the case where only one side expands and contracts, the damping force can be increased when low frequency vibration is input, and the effect of reducing the damping force when high frequency vibration is input is exhibited.

  When vibrations in a low frequency range are input to the fluid pressure dampers D1 and D2, the resistance given to the flow of hydraulic oil that the first valve element V3 and the second valve element V4 pass is increased, When vibrations in a high frequency range are input to the pressure dampers D1 and D2, it is only necessary to reduce the resistance given to the flow of hydraulic oil through which the first valve element V3 and the second valve element V4 pass. In the suspension device S5 of the embodiment, the first valve element is utilized by utilizing the high pressure in the first flow path side pressure chamber 82 and the second flow path side pressure chamber 92 when low frequency vibration is input to each fluid pressure damper D1. The resistance given to the flow of hydraulic fluid by V3 and the second valve element V4 is increased. Even in this case, when vibrations in a high frequency range are input to the fluid pressure dampers D1 and D2, the first flow path P1 and the second flow path to the first flow path side pressure chamber 82 and the second flow path side pressure chamber 92 are provided. When a delay occurs in the pressure transmission in the flow path P2 and vibrations in the low frequency range are input to the fluid pressure dampers D1 and D2, the first flow is supplied to the first flow path side pressure chamber 82 and the second flow path side pressure chamber 92. Since the pressure in the path P1 and the second flow path P2 is transmitted, it is possible to reduce the resistance given to the flow of hydraulic oil that the first valve element V3 and the second valve element V4 pass when high-frequency vibration is input. it can. Therefore, it is also possible to change the flow resistance of the first valve element V3 and the second valve element V4 using the pressure in the first flow path side pressure chamber 82 and the second flow path side pressure chamber 92. When such first valve element V3 and second valve element V4 are used, the first accumulator side pressure chamber 83 of the first sub cylinder 80 is connected to the first accumulator A1, and the second sub cylinder 90 The two accumulator side pressure chambers 93 may be connected to the second accumulator A2. Of course, even in this embodiment, the flow area of the first valve element V3 is changed by the displacement of the first free piston 81, and the flow path of the second valve element V4 is changed by the displacement of the second free piston 91. The area may be changed.

  As described above, even in the suspension device S5 of the present embodiment, the flow path area of the first valve element V3 or the second valve element V4 becomes large at the time of high-frequency vibration input while suppressing rolling of the vehicle body. Accordingly, the damping force generated by each of the fluid pressure dampers D1 and D2 is reduced, and the damping force can be exerted according to the basic operation without exhibiting the damping force reduction effect for the input of the low frequency vibration.

  In addition, whether the first accumulator side pressure chamber 83 and the second accumulator side pressure chamber 93 of the first damping force variable mechanism C3 and the second damping force variable mechanism C4 are each a sealed space filled with gas or opened to the atmosphere, Alternatively, the configuration in which the first accumulator A1 and the second accumulator A2 are connected without resistance can be applied to the suspension device S4 of FIG.

  Next, a suspension device S6 in still another modification example of the second embodiment shown in FIG. 14 will be described. The suspension device S6 uses a first damping force variable mechanism C5 to vary the resistance given to the flow of hydraulic oil that the first discharge side valve element Vp1 passes in addition to the first valve element V3 in the suspension device S3, and the suspension device S3. In addition to the second valve element V4, the resistance given to the flow of hydraulic oil that the second discharge side valve element Vp2 passes is made variable by the second damping force variable mechanism C6.

  More specifically, the first damping force variable mechanism C5 is slidably inserted into the third sub cylinder 130 and the third sub cylinder 130 connected to the first flow path P1 in addition to the configuration shown in FIG. The third free piston 131, the third flow-side pressure chamber 132 and the third accumulator-side pressure chamber 133 partitioned in the third sub-cylinder 130 by the third free piston 131, and the third free piston 131 to the third sub-cylinder 130. A third spring element 134 that exerts a biasing force that positions the cylinder 130 in a neutral position and suppresses displacement from the neutral position of the third free piston 131, and a third flow path side pressure chamber 132 are connected to the first flow path P1. Of the flow path 137 connecting the orifice 136 provided in the middle of the flow path 135 connected to the first accumulator A1 and the third accumulator side pressure chamber 133 It is configured with an orifice 138 provided in, so that the amount of displacement from the neutral position of the third free piston 131 increases the flow path area of the first exhaust side valve element Vp1 becomes smaller.

In addition to the configuration shown in FIG. 10, the second damping force variable mechanism C <b> 6 includes a fourth sub cylinder 140 connected to the second flow path P <b> 2 and a fourth sub cylinder 140 slidably inserted into the fourth sub cylinder 140. The four free pistons 141, the fourth flow path side pressure chamber 142 and the fourth accumulator side pressure chamber 143 partitioned in the fourth sub cylinder 140 by the fourth free piston 141, and the fourth free piston 141 into the fourth sub cylinder 140. the fourth spring element 144 exerts a suppressing biasing force of the displacement from the neutral position of the fourth free-piston 141 with positioning to the neutral position against the fourth flow path side pressure chamber 142 to the second passage P 2 An orifice 146 provided in the middle of the flow path 145 to be connected and an oval provided in the middle of the flow path 147 to connect the fourth accumulator side pressure chamber 143 to the second accumulator A2. The second exhaust piston element 141 is configured such that the flow passage area of the second discharge side valve element Vp2 decreases as the displacement amount from the neutral position of the fourth free piston 141 increases.

  The suspension device S6 is configured as described above. By adopting the first damping force variable mechanism C5 and the second damping force variable mechanism C6 in this example, high-frequency vibrations are input to the fluid pressure dampers D1 and D2. Then, not only the first valve element V3 and the second valve element V4 but also the first discharge side valve element Vp1 and the second discharge side valve element Vp2 reduce the resistance to the flow through which the hydraulic oil passes, and each fluid pressure When low-frequency vibration is input to the dampers D1 and D2, not only the first valve element V3 and the second valve element V4 but also the flow through which the hydraulic oil passes not only through the first discharge side valve element Vp1 and the second discharge side valve element Vp2 Increase the resistance against.

  Therefore, the differential pressure between the expansion side chambers RR1, LR1 and the compression side chambers RR2, LR2 can be further reduced when the high frequency vibration is input, and the expansion side chambers RR1, LR1 and the compression side chamber RR2, when the low frequency vibration is input. The differential pressure with LR2 can be further increased.

  Therefore, in the suspension device S6 of the present embodiment, the rolling comfort of the vehicle can be further improved when high-frequency vibration is input while the rolling of the vehicle body can be further suppressed.

  In the suspension device S6, as shown in FIG. 15, a first sub-connection path JS1 that bypasses the first valve element V3 and the first discharge side valve element Vp1 and connects the first flow path P1 and the first accumulator A1; The fifth valve element V5, which is provided in the first sub-connection path JS1 and is capable of giving resistance to the flow of hydraulic oil passing therethrough, bypasses the second valve element V4 and the second discharge side valve element Vp2, and A second sub-connection path JS2 that connects the two flow paths P2 and the second accumulator A2, and a sixth valve element V6 that is provided in the second sub-connection path JS2 and can provide resistance to the flow of hydraulic fluid that passes therethrough. May be provided. In this case, the fifth valve element V5 always keeps the first flow path P1 and the first accumulator A1 in communication, and the sixth valve element V6 always keeps the second flow path P2 and the second accumulator A2 in communication. The first valve element V3 and the first discharge side valve element Vp1 may be set so as to close the first connection path J1, and the second valve element V4 and the second discharge side valve element Vp2 are connected to the second connection path J1. It may be set to close the path J2.

  Also in each suspension device S6 shown in FIG. 14, hydraulic oil is discharged from the sub-cylinders in parallel with the orifices 86, 88, 96, 98, 136, 138, 146, and 148, similarly to the suspension devices S1 and S2. Needless to say, a check valve may be provided to allow the flow in a specific direction.

  As shown in FIG. 16, even in the suspension device S6, the first damping force variable mechanism C5 and the second damping force change mechanism C5 and the second damping device S5 of another modification example of the second embodiment shown in FIG. The first accumulator side pressure chamber 83, the third flow path side pressure chamber 132, the second accumulator side pressure chamber 93, and the fourth flow path side pressure chamber 142 of the damping force variable mechanism C6 are set as a sealed space filled with gas or opened to the atmosphere. It is also possible to connect the first accumulator A1 and the second accumulator A2 without resistance. Further, as shown in the figure, the first valve element V3 and the second valve element V4 can be used. Can be changed to the first valve element V3 and the second valve element V4 shown in FIG.

In the suspension device S6 shown in FIG. 16, the flow path resistance of the first discharge side valve element Vp1 is varied by the pressure of the third accumulator side pressure chamber 133, and the flow path of the second discharge side valve element Vp2 is changed. The resistance is made variable by the pressure in the fourth accumulator side pressure chamber 143. Even in this case, when vibrations in a high frequency range are input to the fluid pressure dampers D1 and D2, the first accumulator A1 to the third accumulator side pressure chamber 133 and the fourth accumulator side pressure chamber 143 and When a delay occurs in the pressure transmission of the second accumulator A2 and vibrations in the low frequency range are input to the fluid pressure dampers D1 and D2, the third accumulator side pressure chamber 133 and the fourth accumulator side pressure chamber 143 are provided. Since the pressures of the first accumulator A1 and the second accumulator A2 are transmitted to the hydraulic fluid, the first discharge side valve element Vp1 and the second discharge side valve element Vp2 are given to the flow of hydraulic oil that passes through the high frequency vibration input. Resistance can be reduced. Therefore, the flow path resistance of the first discharge side valve element Vp1 and the second discharge side valve element Vp2 is changed using the pressure in the third accumulator side pressure chamber 133 and the fourth accumulator side pressure chamber 143. Is also possible. In the case of using such a first discharge-side valve element Vp1 and a second discharge-side valve element Vp2, connecting the third flow path side pressure chamber 132 of the third sub-cylinder 130 into the first passage P1, the fourth sub The fourth flow path side pressure chamber 142 of the cylinder 140 may be connected to the second flow path P2. Of course, even in this embodiment, the flow area of the first discharge side valve element Vp1 is changed by the displacement of the third free piston 131, and the second discharge side valve element is changed by the displacement of the fourth free piston 141. You may make it change the flow-path area of Vp2.

  In order to specifically configure the first damping force variable mechanism C5 (second damping force variable mechanism C6) in the suspension device S6 described above, two damping force variable units U are used as shown in FIG. The damping force variable unit U is given resistance by the leaf valve 118 to the flow from the first flow path P1 (second flow path P2) to the first accumulator A1 (second accumulator A2), and the other damping force is variable. The unit U may be provided with resistance by the leaf valve 118 against the flow from the first accumulator A1 (second accumulator A2) toward the first flow path P1 (second flow path P2).

  Therefore, in the suspension device S6 shown in FIG. 17, one damping force variable unit U is housed in the connecting portion 60b in the specific first accumulator A1 (second accumulator A2), and the one damping force variable unit is included. A casing 150 that fixes U to the connecting portion 60b and accommodates the other variable damping force unit U is provided. The casing 150 includes a central plate 150a and an accommodation cylinder 150b that is provided above the central plate 150a in FIG. 17 and accommodates the other variable damping force unit U. The central plate 150a is provided in the connecting portion 60b. Inserted and fixed by a snap ring 151.

  The central plate 150a has a first flow path P1 (second flow path P2) through a passage 150c that opens from the lower end and communicates with the first accumulator A1 (second accumulator A2) and a passage 60c provided in the connecting portion 60b. And a passage 150d communicating with the inside of the housing cylinder 150b.

  Further, the lower end in FIG. 17 of the storage cylinder 150b is opened in the connecting portion 60b so as to be able to communicate with the first flow path P1 (second flow path P2), and the upper end in FIG. It is open to one accumulator A1 (second accumulator A2).

  In the connecting portion 60b, one damping force variable unit U resists the flow from the first flow path P1 (second flow path P2) toward the first accumulator A1 (second accumulator A2) by the leaf valve 118. The other damping force variable unit U is accommodated in the accommodating cylinder 150b with respect to the flow from the first accumulator A1 (second accumulator A2) toward the first flow path P1 (second flow path P2). The leaf valve 118 is accommodated in a direction that provides resistance. In addition, the direction which gives resistance by the leaf valve 118 with respect to the flow which goes to the 1st flow path P1 (2nd flow path P2) from the 1st accumulator A1 (2nd accumulator A2) in the connection part 60b. The damping force variable unit U is resisted by the leaf valve 118 against the flow from the first flow path P1 (second flow path P2) to the first accumulator A1 (second accumulator A2) in the storage cylinder 150b. It can also be accommodated in the direction it is given.

  With this configuration, the suspension device S6 can be specifically configured. Even in the suspension device S6, the first damping force variable mechanism C5, the first valve element V3, and the first discharge side valve element Vp1 are accommodated in the first accumulator A1, and the second damping force variable mechanism C6. Since the second valve element V4 and the second discharge side valve element Vp2 are accommodated in the second accumulator A2, the fluid pressure dampers D1 and D2 are simply connected by the first flow path P1 and the second flow path P2. The suspension device S6 can be formed, and attachment to the vehicle becomes very easy.

  Finally, the suspension device S7 of the third embodiment will be described. As shown in FIG. 18, the suspension device S7 according to the third embodiment has a first damping force variable mechanism C7 and a second damping force variable mechanism C8 with respect to the suspension device S1 according to the first embodiment. Is different, and further, a first bypass path B1 that bypasses the first valve element V1 and connects the first flow path P1 and the first accumulator A1, and a first bypass path B1 that is provided in the first bypass path B1 to the first flow path P1. A third valve element V7 capable of providing resistance to the flow of fluid toward the accumulator A1, and a resistance provided to the flow of fluid from the first accumulator A1 to the first flow path P1 provided in the first bypass passage B1. Is provided in the second bypass passage B2 and the second bypass passage B2 that bypass the second valve element V2 and connect the second passage P2 and the second accumulator A2 A fourth valve element V8 capable of giving resistance to the flow of fluid from the second flow path P2 to the second accumulator A2, and a second flow path from the second accumulator A2 to the second flow path A2. It differs in that it includes a fourth discharge valve element Vp4 that can provide resistance to the flow of fluid toward P2.

  The third valve element V7, the fourth valve element V8, the third discharge side valve element Vp3 and the fourth discharge side valve element Vp4 are composed of a throttle valve and a check valve. A damping valve as shown in FIG. 2 that allows only the flow of hydraulic oil and provides resistance to the flow of hydraulic oil passing therethrough may be used.

  In this embodiment, the first damping force variable mechanism C7 includes a first sub cylinder 160 connected to the first flow path P1, and a first free piston 161 slidably inserted into the first sub cylinder 160. The first flow path side pressure chamber 162 and the first accumulator side pressure chamber 163 defined in the first sub cylinder 160 by the first free piston 161 and the first free piston 161 are positioned to the neutral position with respect to the first sub cylinder 160. In addition, a first spring element 164 that exerts an urging force that suppresses displacement from the neutral position of the first free piston 161 and a first flow path side pressure chamber 162 are provided in the middle of the flow path 165 that connects to the first flow path P1. Orifice 166 and an orifice provided in the middle of a flow path 167 connecting the first accumulator side pressure chamber 163 to the first accumulator A1. 68, a check valve W1 provided in parallel with the orifice 166 in the flow path 165 and allowing only the flow in the direction of discharging the hydraulic oil from the first sub-cylinder 160, and in parallel with the orifice 168 in the flow path 167. And a check valve X1 that allows only the flow in the direction of discharging the hydraulic oil from the first sub-cylinder 160, and the first free piston 161 is displaced first when the displacement amount from the neutral position is larger than a predetermined amount. And a first opening / closing valve 169 that blocks the bypass passage B1. In this case, the first spring element 164 is composed of a pair of springs energizing the first free piston 161, but may be composed of a single spring.

  In this embodiment, the second damping force variable mechanism C8 includes a second sub cylinder 170 connected to the second flow path P2, and a second free piston 171 slidably inserted into the second sub cylinder 170. A second flow path side pressure chamber 172 and a second accumulator side pressure chamber 173 partitioned in the second sub cylinder 170 by the second free piston 171 and the second free piston 171 in a neutral position with respect to the second sub cylinder 170. A second spring element 174 that exerts an urging force that suppresses displacement from the neutral position of the second free piston 171 and a flow path 175 that connects the second flow path side pressure chamber 172 to the second flow path P2. And an orifice provided in the middle of a flow path 177 connecting the second accumulator side pressure chamber 173 to the second accumulator A2. 78, a check valve Y1 provided in parallel with the orifice 176 in the flow path 175 and allowing only the flow in the direction of discharging hydraulic oil from the second sub-cylinder 170, and in parallel with the orifice 178 in the flow path 177. And a check valve Z1 that allows only flow in the direction of discharging hydraulic oil from the second sub-cylinder 170, and the second free piston 171 has a second displacement when the amount of displacement from the neutral position exceeds a predetermined amount. And a second opening / closing valve 179 for blocking the bypass passage B2. In this case, the second spring element 174 is composed of a pair of springs that are energized with the second free piston 171 interposed therebetween, but may be composed of a single spring.

In the first damping force variable mechanism C7, when the first free piston 161 is displaced by a predetermined amount or more from the neutral position, the first on- off valve 169 blocks the first bypass passage B1, and the first free piston 161 is moved from the neutral position. Is less than the predetermined amount, the first bypass passage B1 is opened, and the third valve element V7 and the third discharge side valve element Vp3 are made effective. The first free piston 161 is displaced from the neutral position by a predetermined amount or more when low frequency vibration is input to each of the fluid pressure dampers D1 and D2, and therefore when the low frequency vibration is input, the first flow path P1 and the first flow path With the accumulator A1, hydraulic oil is exchanged only through the first valve element V1.

Even in the second damping force variable mechanism C8, when the second free piston 171 is displaced from the neutral position by a predetermined amount or more, the second on- off valve 179 blocks the second bypass passage B2, and the second free piston 171 is moved from the neutral position. Is less than the predetermined amount, the second bypass passage B2 is opened, and the fourth valve element V8 and the fourth discharge side valve element Vp4 are made effective. The second free piston 171 is displaced from the neutral position by a predetermined amount or more when low frequency vibrations are input to the fluid pressure dampers D1 and D2. Therefore, when the low frequency vibrations are input, With the second accumulator A2, hydraulic oil is exchanged only through the second valve element V2.

  Therefore, in this suspension device S7, when vibration in a low frequency region is input to each of the fluid pressure dampers D1 and D2, the first bypass passage B1 and the second bypass passage B2 are shut off, and the first valve Since only the element V1 and the second valve element V2 are effective, the resistance given to the flow of hydraulic oil is increased, the damping force generated by each fluid pressure damper D1, D2 is increased, and each fluid pressure damper D1, D2 When vibration in a high frequency range is input, the first bypass path B1 and the second bypass path B2 are opened, and the third valve element V7 and the second valve element V2 in addition to the first valve element V1 and the second valve element V2. Since the three discharge side valve element Vp3, the fourth valve element V8, and the fourth discharge side valve element Vp4 become effective and the resistance given to the flow of the passing hydraulic fluid becomes small, each fluid pressure damper D1, D2 is generated. Reduce the damping force Door can be.

  As described above, even in the suspension device S7 according to the third embodiment, as in the suspension device S1 according to the first embodiment, each fluid pressure damper D1 is used in a situation where the vehicle turns and the vehicle body rolls. , D2 is a scene that can suppress the rolling by increasing the damping force, and only one wheel gets over the uneven surface of the road surface or passes through the bumpy road, and high frequency vibration is input. In a situation where the pressure dampers D1 and D2 are in reverse phase or only one of them is expanded and contracted at a high speed, it is possible to reduce the damping force and improve the riding comfort in the vehicle.

  In the present embodiment, the third valve element V7, the fourth valve element V8, the third discharge side valve element Vp3, and the fourth discharge side valve element Vp4 are provided. However, the damping force of each of the fluid pressure dampers D1 and D2 can be reduced when high-frequency vibration is input. By providing the third valve element V7, the fourth valve element V8, the third discharge side valve element Vp3, and the fourth discharge side valve element Vp4, it is possible to arbitrarily set the damping characteristic when the damping force is reduced. In addition, a configuration in which the third valve element V7 and the fourth valve element V8 have only a throttle that allows the flow of hydraulic oil in both directions can be employed. In this case, the third discharge side valve element Vp3 and the fourth valve element V8 can be employed. The discharge side valve element Vp4 may be provided or eliminated.

  The first damping force variable mechanism C7 is a predetermined amount that is a displacement amount from the neutral position of the first free piston 161 that blocks the first bypass path B1, and the second damping force variable mechanism C8 is the first that blocks the second bypass path B2. The predetermined amount that is the amount of displacement from the neutral position of the two free pistons 171 can be arbitrarily set. Further, in this case, since the first spring element 164 and the second spring element 174 are provided, the first free piston 161 and the second free piston 171 are returned to the neutral position, and each fluid pressure damper is surely received when the high frequency vibration is input. The damping force of D1 and D2 can be reduced.

  Further, check valves W1, X1, Y1, and Z1 are provided in parallel with the orifices 166, 168, 176, and 178 to allow only the flow in the direction in which the hydraulic oil is discharged from the first sub cylinder 160 and the second sub cylinder 170. Therefore, it is possible to give directionality to the displacement characteristics from the neutral position of the first free piston 161 and the second free piston 171. For example, the fluid pressure dampers D1 and D2 expand and contract in the same phase. The damping force characteristics on the extension side and the compression side can be set individually.

  In order to specifically configure the suspension device S7 in the third embodiment, it may be configured as shown in FIG. The specific suspension device S7 differs from the specific suspension device S1 shown in FIG. 5 in the configuration of the first damping force variable mechanism C7 (second damping force variable mechanism C8) as shown in FIG. In addition, the third valve element V7 (fourth valve element V8) and the third discharge side valve element Vp3 (fourth discharge side valve element Vp4) are different. It has the same configuration as the suspension device S1 of the embodiment. Accordingly, the fluid pressure dampers D1 and D2 are not shown, and only the portions different from the suspension device S1 will be described in detail.

  The first damping force variable mechanism C7 (second damping force variable mechanism C8) includes a cylindrical sub cylinder 200 as a first sub cylinder (second sub cylinder) and a sub cylinder 200 as shown in FIG. A first free piston (second free piston) that is slidably inserted, a valve body 201 that functions as a first on-off valve (second on-off valve), and an opening at an upper end and a lower end in FIG. The laminated annular plate-shaped spring receiving members 202 and 203, the coil spring 204 interposed between the valve body 201 and the spring receiving member 202, and the valve body 201 and the spring receiving member 203 are interposed. A coil spring 205, an orifice disk plate 206 having an orifice that is stacked on the spring receiving member 202 and communicated with the hole in the center, and an orifice disk plate 206 that is Only the orifice disk plate 206 is closed for the flow of hydraulic oil into the sub-cylinder 200 and only the orifice is made effective, and the reverse flow of the orifice disk plate 206 is opened for the opposite hydraulic oil flow. A valve body 207, an orifice disk plate 208 provided with an orifice that is laminated on the spring receiving member 203 and communicated with the hole in the center, and a working oil that is laminated on the orifice disk plate 208 and goes into the sub cylinder 200 from the outside. And a check valve body 209 that closes only the orifice disk plate 208 for the flow and enables only the orifice, and opens the orifice disk plate 208 for the opposite hydraulic oil flow. These members are accommodated in a cylindrical accommodation cylinder 210 that is screwed to the rod 66. It has become as to be.

The sub-cylinder 200 is provided with two through holes 200a and 200b that communicate from the outside to the inside. Between the through holes 200a and 200b, an enlarged diameter portion 200c is provided over the entire circumference. ing. When the sub cylinder 200 is housed in the housing cylinder 210, the enlarged diameter portion 200c is fitted to the inner periphery of the housing cylinder 210, and between the sub cylinder 200 and the housing cylinder 210 and above and below the expanded diameter portion 200c. An annular gap 211 that communicates with the through hole 200a and an annular gap 212 that communicates with the through hole 200b are formed.
Further, the valve body 201 includes a lower chamber 213 serving as a first flow path side pressure chamber (second flow path side pressure chamber) and an upper chamber 214 serving as a first accumulator side pressure chamber (second accumulator side pressure chamber). An annular groove 201a is formed at the center in the outer peripheral axial direction. The valve body 201 is sandwiched between the coil springs 204 and 205 and positioned at the neutral position. When the valve body 201 is displaced from the neutral position, the valve body 201 receives an urging force from the coil springs 204 and 205 to return to the neutral position. Therefore, in this case, the first spring element (second spring element) is formed by the coil springs 204 and 205.

  Further, when the valve body 201 is located at the neutral position, the through hole 200a and the through hole 200b are communicated with each other by the annular groove 201a. When the valve body 201 is displaced upward by a predetermined amount or more, the outer periphery is transparent. The hole 200b is blocked, and conversely, when the valve body 201 is displaced downward by a predetermined amount or more, the through hole 200a is blocked at the outer periphery.

  Further, a cup-shaped holder member 216 is stacked on the check valve body 207 in FIG. 19 via an annular spacer 218, and an annular spacer 219 is disposed on the check valve body 209 in the lower part in FIG. A cup-shaped holder member 217 is stacked therebetween. These holder members 216 and 217 are fitted to the outer periphery of the sub-cylinder 200 so that the members stacked on the sub-cylinder 200 are sandwiched by the holder members 216 and 217 and positioned in the radial direction. Thus, the holder members 216 and 217 make it easy to incorporate each member assembled to the sub cylinder 200 into the housing cylinder 210.

  In addition, a lid body 215 that is accommodated on the inner periphery of the accommodation cylinder 210 is provided above the holder member 216 in FIG. The lid body 215 is accommodated in the housing cylinder 210 and the lid body 215a on which the holder member 216 is stacked, the shaft portion 215b extending from the upper end of the lid body 215a, and the lid body 215a opening from the tip of the shaft portion 215b. A passage 215c leading to the lower end is provided.

  The lower chamber 213 of the sub cylinder 200 is connected to the first flow path P1 through the hole 217a provided in the holder member 217 and the rod 66, and the upper chamber 214 is connected via the hole 216a provided in the holder member 216 and the passage 215c. To the first accumulator A1 (second accumulator A2).

  The annular groove 201a communicates with the upper part of the lid body 215a via a notch 216b provided in the holder member 216 and a gap between the lid body 215a and the housing cylinder 210. The annular gap 212 is formed by the holder member 217. And communicated with the first flow path P1 (second flow path P2) through the notch 217b and the inside of the rod 66.

A valve disc 220 and leaf valves 221 and 222 stacked on the top and bottom of the valve disc 220 are mounted on the outer periphery of the shaft portion 215 b of the lid 215. Valve disc 220 is fitted to the inner periphery of the holding cylinder 210 has partitions the annular space 223 between the lid body 215a of the valve disk 2 2 0 and the lid 215.

  Further, the valve disc 220 includes a supply port 220a and a discharge port 220b. Therefore, the space 223 can communicate with the first accumulator A1 (second accumulator A2) through the supply port 220a and the discharge port 220b. The supply port 220a is opened and closed by a leaf valve 221 stacked on the upper side of the valve disc 220 in FIG. 19, and the leaf valve 221 functions as a third valve element (fourth valve element). The other discharge port 220b is opened and closed by a leaf valve 222 stacked below the valve disc 220 in FIG. 19, and the leaf valve 222 is a third discharge side valve element (fourth discharge side valve element). Function as.

  In addition, an annular cap 224 that is fitted to the inner periphery of the opening end of the receiving cylinder 210 and attached to the outer periphery of the shaft portion 215 b is stacked above the leaf valve 221, and the pipe end cap 224 of the receiving cylinder 210 is stacked. By caulking the upper side, each member except for the valve body 201 accommodated in the accommodation cylinder 210 is fixed in the accommodation cylinder 210.

In the first damping force variable mechanism C7 (second damping force variable mechanism C8) configured as described above, when the valve body 201 is positioned at the neutral position, the through hole 200a and the through hole are formed by the annular groove 201a. The annular gap 211 and the annular gap 212 are communicated with each other by communicating with 200b, and the inside of the rod 66 is communicated with the space 223 through the annular gaps 211 and 212. Since the space 223 communicates with the first accumulator A1 (second accumulator A2) and the inside of the rod 66 communicates with the first flow path P1 (second flow path P2), the annular groove 201a, the through holes 200a, 200b, A first bypass path B1 (second bypass path B2) is formed by the annular gaps 211 and 212, the supply port 220a, and the discharge port 220b. In a state where the valve body 201 is in the neutral position and the first bypass passage B1 (second bypass passage B2) is opened, the first accumulator A1 (second accumulator A2) from the first passage P1 (second passage P2). The leaf valve 221 provides resistance while opening the supply port 220a together with the leaf valve 64 that provides resistance to the flow of hydraulic oil that the partition member 62 passes through the supply port 62a. Thus, each of the fluid pressure dampers D1 and D2 exhibits a low damping force, and with respect to the flow of hydraulic oil from the first accumulator A1 (second accumulator A2) to the first flow path P1 (second flow path P2), The leaf valve 222 opens the discharge port 220b together with the leaf valve 65 that provides resistance to the flow of hydraulic oil through which the partition member 62 passes through the discharge port 62b. Will be given anti-a, the hydraulic damper D1, D2 exhibits a low damping force.

  When the valve body 201 is displaced upward from the neutral position, the through hole 200b is closed by the outer periphery of the valve body 201, the first bypass path B1 (second bypass path B2) is blocked, and conversely, the valve body 201 is moved downward. When the first through passage 200a is blocked by the outer periphery of the valve body 201 and the first bypass passage B1 (second bypass passage B2) is shut off, only the leaf valve 64 or the leaf valve 65 flows the hydraulic oil. Therefore, the fluid pressure dampers D1 and D2 exhibit a high damping force.

  Therefore, even in this specific suspension device S7, when the vehicle turns and the vehicle body rolls, each of the fluid pressure dampers D1 and D2 can suppress the rolling by increasing the damping force. In this situation, only the wheels get over the road surface irregularities or pass through the bumpy road, where high frequency vibration is input, and each fluid pressure damper D1 and D2 expands or contracts at high speed in reverse phase or only on one side. In the situation, the damping force can be reduced to improve the riding comfort in the vehicle.

  In the specific suspension device S7, the first damping force variable mechanism C7, the first valve element V1, the third valve element V7, and the third discharge side valve element Vp3 are accommodated in the first accumulator A1. Since the second damping force variable mechanism C8, the second valve element V2, the fourth valve element V8, and the fourth discharge side valve element Vp4 are accommodated in the second accumulator A2, the fluid pressure dampers D1, D2 are respectively The suspension device S7 can be formed simply by connecting the one flow path P1 and the second flow path P2, and the attachment to the vehicle becomes very easy.

  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.

2 Cylinder 3 Piston 10, 80, 160 First sub cylinder 11 First free piston 12, 82, 162 First flow path side pressure chamber 13, 83, 163 First accumulator side pressure chamber 14, 84, 164 First spring element 16, 18, 26, 28, 86, 88, 96, 98, 136, 138, 146, 148, 166, 168, 176, 178 Orifice 20, 90, 170 Second sub cylinder 21 Second free piston 22, 92, 172 First Two flow path side pressure chambers 23, 93, 173 Second accumulator side pressure chambers 24, 94, 174 Second spring element 130 Third sub cylinder 131 Third free piston 132 Third flow path side pressure chamber 133 Third accumulator side pressure chamber 134 Third spring element 140 Fourth sub-cylinder 141 Fourth free piston 142 Fourth flow path side pressure 143 Fourth accumulator side pressure chamber 144 Fourth spring element 169 First on-off valve 179 Second on-off valve A1 First accumulator A2 Second accumulator B1 First bypass passage B2 Second bypass passage C1, C3, C5, C7 First damping Force variable mechanism C2, C4, C6, C8 Second damping force variable mechanism D1, D2 Fluid pressure damper J1 First connection path J2 Second connection path JS1 First sub connection path JS2 Second sub connection path P1 First flow path P2 First Two flow paths LR1, RR1 Stretch side chamber LR2, RR2 Pressure side chamber S1, S2, S3, S4, S5, S6, S7 Suspension device V1 First valve element V2 Second valve element V3 Third valve element V4 Fourth valve element V5 First Five valve element V6 Sixth valve element Vp1 First discharge side valve element VP2 Second discharge side valve element Vp3 Third discharge side valve element Vp4 Fourth discharge side valve element W, W1, X, X1 Y, Y1, Z, Z1 check valve

Claims (18)

A pair of fluid pressure dampers having an extension side chamber and a pressure side chamber interposed between a vehicle body and wheels of the vehicle and partitioned by a piston in a cylinder;
A first flow path connecting the extension side chamber of one fluid pressure damper and the pressure side chamber of the other fluid pressure damper;
A second flow path connecting the pressure side chamber of the one fluid pressure damper and the extension side chamber of the other fluid pressure damper;
A first accumulator connected to the first flow path via a first connection path;
A second accumulator connected to the second flow path via a second connection path;
A first valve element provided in the first connection path and capable of providing resistance to a flow of fluid from the first connection path toward the first accumulator;
A suspension device comprising: a second valve element provided in the second connection path and capable of providing resistance to a flow of fluid from the second connection path toward the second accumulator,
A first sub-cylinder connected to the first flow path; a first free piston slidably inserted into the first sub-cylinder; and the first flow defined by the first free piston in the first sub-cylinder. the first damping force control for a and a first stream roadside pressure chamber connected to the road damping force each fluid pressure damper is generated by the pressure in the displacement or the first sub-cylinder of the first free piston variable Mechanism,
A second sub-cylinder connected to the second flow path; a second free piston slidably inserted into the second sub-cylinder; and the second sub-cylinder defined by the second free piston. second to the damping force the fluid pressure damper is generated by the pressure of the second flow path side pressure chamber and the displacement or the second sub-cylinder of the second free piston has a connected to the double flow circuit to a variable A suspension device comprising a variable damping force mechanism. The first damping force control mechanism includes a first accumulator-side pressure chamber connected to the upper Symbol first flow path side pressure chamber and the first accumulator which is partitioned by the first free piston within the first sub-cylinder, the and a orifice provided on one or both between the first flow path side pressure chamber and between the first channel and the first accumulator pressure chamber and the first accumulator,
The second damping force control mechanism includes a second accumulator pressure chamber connected to the upper Symbol second flow path side pressure chamber and the second accumulator which is partitioned by the second free piston within the second sub-cylinder, to claim 1, she characterized in that it comprises an orifice provided on one or both of between the second flow path side pressure chamber and the above and the said second accumulator pressure chamber between the second channel second accumulator The suspension device described. The first damping force control mechanism includes a orifice or provided between the upper Symbol first flow path side pressure chamber and the first flow path,
The second damping force control mechanism, the suspension device according to claim 1, characterized in that it comprises a orifice or provided between the second flow path side pressure chamber above SL and the second channel. The first damping force control mechanism includes a check valve which allows only the flow of fluid discharged in parallel to the orifice from the first sub-cylinder,
The second damping force control mechanism, suspension according to claim 2 or 3 characterized by having a check valve which allows only the flow of fluid discharged in parallel to said orifice from said second sub-cylinder apparatus. The first valve element makes the resistance given to the fluid passing by the displacement of the first free piston in the first damping force variable mechanism variable, so that the resistance increases as the displacement amount of the first free piston increases. Set to
The second valve element makes the resistance given to the fluid passing by the displacement of the second free piston in the second damping force variable mechanism variable, so that the resistance increases as the displacement amount of the second free piston increases. The suspension device according to any one of claims 1 to 4, wherein the suspension device is set as follows. The first valve element varies a resistance given to the fluid passing by the pressure of the first flow path side pressure chamber in the first damping force variable mechanism, and the resistance increases when the pressure of the first flow path side pressure chamber increases. Is set to
The second valve element makes the resistance given to the fluid passing by the pressure of the second flow path side pressure chamber in the second damping force variable mechanism variable, and the resistance becomes higher when the pressure of the second flow path side pressure chamber becomes higher. The suspension device according to any one of claims 1 to 4, wherein the suspension device is set to be large. A first discharge-side valve element that is provided in the first connection path and is provided in parallel with the first valve element to provide resistance to a fluid flow from the first accumulator toward the first flow path;
A second discharge side valve element that is provided in the second connection path and is provided in parallel with the second valve element to provide resistance to the flow of fluid from the second accumulator toward the second flow path. The suspension device according to any one of claims 1 to 6. The first damping force variable mechanism includes a third flow path side pressure chamber connected to the first flow path partitioned by a third free piston in a third sub cylinder, and a third accumulator side pressure connected to the first accumulator. a chamber and, an orifice provided on one or both of between the third flow between roadside pressure chamber and the first flow path and the third accumulator pressure chamber and the first accumulator,
The second damping force variable mechanism includes a fourth flow path side pressure chamber connected to the second flow path partitioned by a fourth free piston in a fourth sub cylinder, and a fourth accumulator side connected to the second accumulator. a pressure chamber, and an orifice provided on one or both of between the fourth flow path side pressure chamber and between the second channel and the fourth accumulator pressure chamber and said second accumulator,
The first discharge side valve element makes the resistance given to the fluid passing by the displacement of the third free piston in the first damping force variable mechanism variable, and the resistance increases as the displacement amount of the third free piston increases. Is set to be
The second discharge side valve element makes the resistance given to the fluid passing by the displacement of the fourth free piston in the second damping force variable mechanism variable, and the resistance increases as the displacement amount of the fourth free piston increases. The suspension device according to claim 7, wherein the suspension device is set as follows. The first damping force variable mechanism includes a third sub-cylinder defined by a third sub-cylinder connected to the first accumulator and a third free piston slidably inserted into the third sub-cylinder. has a third accumulator-side pressure chamber connected to said first accumulator, and an orifice provided between the first accumulator and the third accumulator-side pressure chamber,
The second damping force variable mechanism includes a fourth sub-cylinder partitioned by a fourth sub-cylinder connected to the second accumulator and a fourth free piston slidably inserted into the fourth sub-cylinder. has a fourth accumulator-side pressure chamber connected to the second accumulator, and an orifice provided between the second accumulator and the fourth accumulator-side pressure chamber,
The first discharge side valve element makes the resistance given to the fluid passing by the displacement of the third free piston in the first damping force variable mechanism variable, and the resistance increases as the displacement amount of the third free piston increases. Is set to be
The second discharge side valve element makes the resistance given to the fluid passing by the displacement of the fourth free piston in the second damping force variable mechanism variable, and the resistance increases as the displacement amount of the fourth free piston increases. The suspension device according to claim 7, wherein the suspension device is set as follows. The first damping force variable mechanism includes a third sub-cylinder defined by a third sub-cylinder connected to the first accumulator and a third free piston slidably inserted into the third sub-cylinder. has a third accumulator-side pressure chamber connected to said first accumulator, and an orifice provided between the first accumulator and the third accumulator-side pressure chamber,
The second damping force variable mechanism includes a fourth sub-cylinder partitioned by a fourth sub-cylinder connected to the second accumulator and a fourth free piston slidably inserted into the fourth sub-cylinder. has a fourth accumulator-side pressure chamber connected to the second accumulator, and an orifice provided between the second accumulator and the fourth accumulator-side pressure chamber,
The first discharge side valve element makes the resistance given to the fluid passing by the pressure of the third accumulator side pressure chamber in the first damping force variable mechanism variable, and when the pressure of the third accumulator side pressure chamber increases, The resistance is set to be large,
The second discharge side valve element makes the resistance given to the fluid passing by the pressure of the fourth accumulator side pressure chamber in the second damping force variable mechanism variable, and when the pressure of the fourth accumulator side pressure chamber increases, The suspension device according to claim 7, wherein the suspension device is set to increase resistance. A first bypass path that bypasses the first valve element and connects the first path and the first accumulator;
A second bypass path that bypasses the second valve element and connects the second flow path and the second accumulator;
The first damping force control mechanism, the displacement of the first free piston has a first shut-off valve for opening and closing the first bypass passage becomes equal to or higher than the predetermined displacement,
The second damping force control mechanism of claim 1, 2, 3, 4, characterized in that displacement of the second free piston has a second on-off valve for opening and closing the second bypass passage becomes equal to or greater than a predetermined displacement The suspension device according to any one of claims. A third valve element provided in the first bypass passage and capable of giving resistance to a flow of fluid from the first passage toward the first accumulator;
A third discharge-side valve element provided in the first bypass path and capable of providing resistance to a flow of fluid from the first accumulator toward the first flow path;
A fourth discharge side valve element that is provided in the second bypass path and can provide resistance to the flow of fluid from the second accumulator toward the second flow path;
The fourth valve element provided in the second bypass passage and capable of giving resistance to a flow of fluid from the second passage toward the second accumulator. Suspension device. A first sub-connection path that bypasses the first valve element and connects the first flow path and the first accumulator;
A fifth valve element provided in the first sub-connection path and capable of giving resistance to a flow of fluid passing therethrough;
A second sub-connection path that bypasses the second valve element and connects the second flow path and the second accumulator;
The suspension according to any one of claims 5 to 10, further comprising: a sixth valve element provided in the second sub-connection path and capable of giving resistance to a flow of fluid passing therethrough. apparatus. The first damping force variable mechanism positions the third free piston to the neutral position with respect to the third sub-cylinder and exerts an urging force that suppresses displacement of the third free piston from the neutral position. It has a third spring element,
The second damping force variable mechanism positions the fourth free piston to a neutral position with respect to the fourth sub-cylinder and exerts an urging force that suppresses displacement of the fourth free piston from the neutral position. The suspension device according to any one of claims 8 to 10, further comprising a fourth spring element. The first damping force varying mechanism positions the first free piston to a neutral position with respect to the first sub-cylinder and exerts an urging force that suppresses displacement of the first free piston from the neutral position. having a first spring element,
The second damping force variable mechanism positions the second free piston to the neutral position with respect to the second sub-cylinder and exerts an urging force that suppresses displacement of the second free piston from the neutral position. The suspension device according to any one of claims 1 to 14, further comprising a second spring element. The first valve element and the first damping force variable mechanism are accommodated in the first accumulator,
The suspension device according to any one of claims 1 to 15, wherein the second valve element and the second damping force variable mechanism are accommodated in the second accumulator. The first valve element, the first discharge side valve element and the first damping force variable mechanism are accommodated in the first accumulator,
The said 2nd valve element, the said 2nd discharge side valve element, and the said 2nd damping force variable mechanism are accommodated in a said 2nd accumulator, The one of Claim 7 to 10 characterized by the above-mentioned. Suspension device. The third valve element, the third discharge side valve element, the first on-off valve and the first damping force variable mechanism are provided in the first accumulator,
The suspension according to claim 12, wherein the fourth valve element, the fourth discharge side valve element, the second on-off valve, and the second damping force variable mechanism are accommodated in the second accumulator. apparatus.

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