JP2009041706A - Shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorber for developing damping force as required without increasing the size and weight, while varying the damping force. <P>SOLUTION: The shock absorber comprises a reservoir R, an elongation side passage 4 connecting an elongation side chamber R1 with the reservoir R, an elongation side damping valve 5 provided on the way of the elongation side passage 4 for giving resistance to the flow of fluid from the elongation side chamber R1 to the reservoir R, an elongation pressure passage 6 connecting the elongation side chamber R1 with a pressure side chamber R2, a pressure reservoir passage 7 connecting the pressure side chamber R2 with the reservoir R, a pressure side damping valve 8 provided on the way of the elongation pressure passage 6 for giving resistance to the flow of fluid from the pressure side chamber R2 to the elongation side chamber R1, and a reservoir side damping valve 9 provided on the way of the pressure reservoir passage 7 for giving resistance to the flow of fluid from the pressure side chamber R2 to the reservoir R. Elongation side sub damping circuits 10a, 10b and pressure side sub damping circuits 11a, 11b are each provided in at least a pair. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improved shock absorber.

  This kind of shock absorber is incorporated in, for example, an automobile, a railway vehicle, a building, etc., and attenuates vibrations in a vibration control target. Here, when the vibration control target is the body of a railway vehicle, a building, etc., regardless of the direction of vibration of the vibration control target, if the vibration speed is the same, the same damping force is exhibited and the damping force is variable. May be desired.

  In order to satisfy these requirements, for example, it is conceivable that the shock absorber is a double rod type, and the flow rate of the fluid passing through each pressure chamber is equal during expansion and contraction. Since the rod moves so as to protrude from the cylinder both at the time and at the time of contraction, there is a disadvantage that the mounting length of the shock absorber becomes long.

Therefore, there is a proposal to set the shock absorber to a single rod type and to a uniflow type in which the fluid flows in one direction. In this uniflow-type shock absorber, the flow of the fluid is one-way from the compression side chamber to the extension side chamber, and the cross-sectional area of the piston and the cross-sectional area of the rod connected to the piston are set in a 2: 1 relationship. Thus, the flow rate flowing out of the cylinder is constant if the stroke amount is the same for both expansion and contraction. If the plurality of damping valves are selectively allowed to pass through the flow of the fluid that flows out, the uniflow type shock absorber exhibits the same damping force as long as the vibration speed is the same during expansion and contraction and is damped. The force can be made variable (see, for example, Patent Document 1).
JP-A-9-183368 (FIG. 2)

  In this uniflow-type shock absorber, as described above, in principle, the generated damping force is the same if the vibration speed is the same regardless of the expansion operation or the contraction operation. Since the fluid has compressibility, the same damping force cannot be generated by both expansion and contraction.

  More specifically, in the uniflow type shock absorber, only the fluid in the expansion side chamber is compressed during expansion, but not only the expansion side chamber but also the fluid in the compression side chamber is compressed during contraction. Then, the amount of fluid to be compressed is different, and the damping force is different between the expansion side and the contraction side, and it is difficult to exert the damping force as intended. Specifically, since the ratio of the cross-sectional area of the piston to the cross-sectional area of the rod is 2: 1, when the piston operates from the neutral position, the amount of compressed fluid when contracted should be about three times the amount of compressed fluid when extended. From this, it can be understood that the damping force is different between the expansion side and the contraction side.

  In particular, in a shock absorber with a long stroke length, this tendency appears remarkably because the cylinder length is long and the amount of fluid is large. Even when hydraulic oil is used as the fluid, gas is mixed in the hydraulic oil, and it is difficult to remove the hydraulic oil.

  Furthermore, in the case of a uniflow type shock absorber, as described above, the piston cross-sectional area and the rod cross-sectional area must be set to a 2: 1 relationship, and the design freedom is low. However, if it is desired to exert different damping force due to expansion and contraction, a damping valve is used depending on the direction of expansion and contraction. It is necessary to make a selection, and a control device is required to select the damping valve, which further increases the size of the device.

  Therefore, the present invention was devised in order to improve the above-mentioned problems, and the object of the present invention is to bring about a damping force as intended without causing an increase in size and weight. To provide a shock absorber capable of making the damping force variable.

  In order to achieve the above-described object, a shock absorber in the problem solving means of the present invention includes a cylinder, a piston that is slidably inserted into the cylinder and that divides the cylinder into an extension side chamber and a pressure side chamber, The rod is connected to the piston at one end and is connected to the piston, the reservoir, the extension side passage communicating with the extension side chamber and the reservoir or the pressure side chamber, and the extension side passage. An expansion side damping valve that provides resistance to the flow of fluid toward the compression side chamber, an expansion passage that communicates the expansion side chamber and the compression side chamber, a pressure reservoir passage that communicates the compression side chamber and the reservoir, A pressure-side damping valve that provides resistance to the flow of fluid from the pressure-side chamber to the expansion-side chamber, and a reserver that is provided in the middle of the pressure reservoir passage and provides resistance to the flow of fluid from the pressure-side chamber to the reservoir And a damping side auxiliary damping circuit and at least one pair of an extension side auxiliary damping circuit and a compression side auxiliary damping circuit, and the extension side auxiliary damping circuit communicates the extension side chamber with the reservoir or the pressure side chamber. An extension side sub-passage, an extension side sub-passage valve provided in the middle of the extension side sub-passage to provide resistance to the flow of fluid from the extension side chamber toward the reservoir or pressure side chamber, and provided in the middle of the extension side sub-passage. An extension side sub-switching valve that opens and closes the extension side sub passage, and the pressure side sub damping circuit includes a pressure extension sub passage that communicates the extension side chamber and the pressure side chamber, and a pressure reservoir sub passage that communicates the pressure side chamber and the reservoir. A pressure side secondary damping valve provided in the middle of the pressure side sub-passage to provide resistance to the flow of fluid from the pressure side chamber toward the pressure side chamber, and a fluid flow provided in the middle of the pressure reservoir side passage to the reservoir from the pressure side chamber Of the reservoir side auxiliary damping valve that gives resistance to the A pressure side sub-switching valve that opens and closes the pressure extension sub-passage, and a reservoir-side sub-switching valve that is provided in the middle of the pressure reservoir sub-passage and opens and closes the pressure reservoir sub-passage. .

  According to the shock absorber of the present invention, even if the bi-flow is set, the damping force can be made variable by selectively functioning the extension side auxiliary damping circuit and the compression side auxiliary damping circuit as a pair.

  In this shock absorber, the fluid in the expansion side chamber is compressed during expansion, and the hydraulic oil in the compression side chamber is compressed instead of the entire cylinder during contraction. The amount of fluid compressed by time does not differ significantly, and the damping force can be generated in the shock absorber by setting the damping valve that acts on the expansion side and contraction side, and the piston speed is the same. If it exists, the same damping force can be exerted on both sides of the expansion and contraction.

  In other words, in this shock absorber, it is possible to adopt a bi-flow while making the damping force variable and exhibiting the desired damping force on both sides of the expansion and contraction, so compare the amount of fluid compressed during expansion and contraction Therefore, the damping force can be sufficiently exerted even with a minute vibration with a very small expansion / contraction amount.

  Furthermore, since this shock absorber is set to bi-flow, there is no restriction on the relationship between the piston cross-sectional area and the rod cross-sectional area, the design freedom of the shock absorber is high, and the piston diameter or rod diameter is strong. Since there is no problem of unnecessarily large diameter, there is no increase in the size and weight of the shock absorber.

  When changing the damping force in the shock absorber, the expansion side damping valve, the pressure side damping valve, the reservoir side damping valve, the stretching side sub damping valve, the pressure side sub damping valve, and the reservoir side sub damping valve are used each time instead of switching the expansion / contraction operation. Since there is no need to make a selection, it is not necessary to intervene a large-scale control device, and in this respect as well, an increase in the size of the entire system including the shock absorber can be avoided.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a circuit diagram of a shock absorber according to an embodiment. FIG. 2 is a damping characteristic diagram of the shock absorber according to the embodiment. FIG. 3 is a circuit diagram of a shock absorber according to a modification of the embodiment.

  As shown in FIG. 1, a shock absorber D in one embodiment includes a cylinder 1 and a piston 2 that is slidably inserted into the cylinder 1 and that partitions the cylinder 1 into an extension side chamber R1 and a pressure side chamber R2. A rod 3 that is movably inserted into the cylinder 1 and has one end connected to the piston 2, a reservoir R, an extension side passage 4 that communicates the extension side chamber R 1 and the reservoir R, and an extension side passage 4. The expansion side damping valve 5 provided in the middle and resists the flow of fluid from the expansion side chamber R1 to the reservoir R, the expansion channel 6 communicating the expansion side chamber R1 and the compression side chamber R2, the compression side chamber R2 and the reservoir R A pressure reservoir passage 7 that communicates with the pressure side passage, a pressure side damping valve 8 that is provided in the middle of the pressure expansion passage 6 and provides resistance to the flow of fluid from the pressure side chamber R2 toward the expansion side chamber R1, and a pressure reservoir passage 7 provided in the middle of the pressure reservoir passage 7 Reserved from pressure side chamber R2 A reservoir side damping valve 9 which provides resistance to the flow of fluid to the R, two pairs of extension-side sub damping circuit 10a, 10b and the compression side sub damping circuit 11a, is configured to include a 11b.

  Hereinafter, each part will be described in detail. The cylinder 1 is formed in a cylindrical shape, and the upper and lower ends thereof are respectively closed by a head member 12 and a bottom member 13 and filled with hydraulic fluid as fluid. In the present embodiment, the fluid is hydraulic oil, but is not limited to this, and may be liquid or gas other than this.

  The cylinder 1 is partitioned into an extension side chamber R1 and a pressure side chamber R2 by a piston 2 slidably inserted. A rod 3 is connected to the left end of the piston 2 in FIG. Is slidably supported on the head member 12.

  In other words, this shock absorber is configured as a single rod-type shock absorber that is advantageous in terms of mounting length.

  Further, the extension side passage 4 communicates the extension side chamber R1 and the reservoir R via the head member 12, and the extension side damping valve 5 is provided in the head member 12. The expansion side damping valve 5 is a pressure proportional valve that opens the expansion side passage 4 and increases the flow area in proportion to the pressure of the expansion side chamber R1 when the pressure in the expansion side chamber R1 exceeds the valve opening pressure. Resistance is provided to the flow of hydraulic oil from the extension side chamber R1 toward the reservoir R. That is, the expansion side damping valve 5 does not open even when the pressure on the expansion side chamber R1 falls below the pressure in the reservoir R, and functions as a check valve.

  Furthermore, in the case of this embodiment, the pressure increasing passage 6 that connects the expansion side chamber R1 and the pressure side chamber R2 is provided in the piston 2, and the pressure side damping valve 8 is also provided in the piston 2. The pressure-side damping valve 8 is a pressure proportional valve that opens the expansion passage 6 when the pressure in the pressure-side chamber R2 exceeds the valve opening pressure and increases the flow passage area in proportion to the pressure in the pressure-side chamber R2. Resistance is provided to the flow of hydraulic oil from the chamber R2 toward the extension side chamber R1. That is, the pressure side damping valve 8 does not open even if the pressure in the pressure side chamber R2 falls below the pressure in the expansion side chamber R1, and functions as a check valve.

  The piston 2 is provided with a pair of relief passages 14 and 15 communicating the extension side chamber R1 and the pressure side chamber R2. The pressure in the extension side chamber R1 is opened in the middle of the one relief passage 14. When the valve pressure is exceeded, an extension side relief valve 16 is provided that opens the relief flow path 14 and communicates the extension side chamber R1 and the pressure side chamber R2, and the pressure in the pressure side chamber R2 is in the middle of the other relief flow path 15. A pressure-side relief valve 17 is provided that opens the relief flow path 15 when the valve-opening pressure is exceeded and communicates the expansion-side chamber R1 and the pressure-side chamber R2.

  In the extension side relief valve 16 and the pressure side relief valve 17, when one of the extension side chamber R1 and the pressure side chamber R2 reaches a predetermined pressure when the shock absorber D is expanded and contracted, the corresponding extension side relief valve 16 or pressure side relief valve 17 is In operation, the pressure is released to the other of the expansion side chamber R1 and the compression side chamber R2, and the generated damping force of the shock absorber D is limited.

  In addition, although the above-mentioned pressure expansion passage 6 and the relief flow paths 14 and 15 may be provided outside the cylinder 1, unnecessary enlargement of the shock absorber D can be avoided by being provided in the piston 2.

  Subsequently, the pressure reservoir passage 7 communicates the pressure side chamber R <b> 2 and the reservoir R via the bottom member 13, and the reservoir side damping valve 9 is provided in the bottom member 13. The reservoir side damping valve 9 is a pressure proportional valve that opens the pressure reservoir passage 7 when the pressure in the pressure side chamber R2 exceeds the valve opening pressure and increases the flow path area in proportion to the pressure in the extension side chamber R1, Resistance is applied to the flow of hydraulic oil from the pressure side chamber R2 toward the reservoir R. That is, the reservoir-side damping valve 9 does not open even when the pressure in the pressure-side chamber R2 falls below the pressure in the reservoir R, and functions as a check valve.

  The bottom member 13 is provided with a suction passage 18 that allows the reservoir R and the pressure side chamber R2 to communicate with each other. In the middle of the suction passage 18, only a flow from the reservoir R to the pressure side chamber R2 is allowed. A valve 19 is provided.

  When the shock absorber D is extended, the expansion side chamber R1 is compressed, so that hydraulic fluid flows out from the expansion side chamber R1 to the reservoir R via the expansion side damping valve 5, and to the compression side chamber R2 the reservoir R Hydraulic fluid is supplied through the suction passage 18. On the contrary, when the shock absorber D performs the contraction operation, the hydraulic oil corresponding to the volume expansion of the expansion side chamber R1 is supplied from the pressure side chamber R2 via the pressure side damping valve 8, and the volume of the rod 3 entering the cylinder 1 is obtained. The hydraulic oil is discharged from the pressure side chamber R2 to the reservoir R through the reservoir side damping valve 9.

  Thus, the shock absorber D is configured as a bi-flow shock absorber instead of a uniflow, and generates a damping force at the expansion side damping valve 5 at the time of expansion, and a damping force at the compression side damping valve 8 and the reservoir side damping valve 9 at the time of contraction. However, when the piston speed is the same, the flow with respect to the valve opening pressure and pressure in the expansion side damping valve 5, the pressure side damping valve 8, and the reservoir side damping valve 9 is such that the same damping force can be generated during expansion and contraction. The proportion of road area is adjusted.

  Subsequently, the extension side sub-attenuation circuit 10a is provided in the middle of the extension side sub-passage 20a and the extension side sub-passage 20a for communicating the extension side chamber R1 and the reservoir R. The expansion side sub damping valve 20b for providing resistance and the convergence switching valve 41 functioning as an expansion side sub switching valve for opening and closing the expansion side sub passage 20a are provided. The compression side sub-attenuation circuit 11a includes a pressure expansion sub passage 21a that communicates the expansion side chamber R1 and the pressure side chamber R2, a pressure reservoir sub passage 21b that communicates the pressure side chamber R2 and the reservoir R, and an intermediate portion of the pressure expansion sub passage 21a. The pressure side secondary damping valve 21c that provides resistance to the flow of fluid from the pressure side chamber R2 to the expansion side chamber R1 and the fluid flow from the pressure side chamber R2 to the reservoir R provided in the middle of the pressure reservoir sub passage 21b. Resistance Function as a reservoir side sub damping valve 21d, a pressure side sub switching valve 21e provided in the middle of the pressure expansion sub passage 21a to open and close the pressure expansion sub passage 21a, and a reservoir side sub switching valve to open and close the pressure reservoir sub passage 21b. And a convergence switching valve 41.

  The expansion side auxiliary passage 20a communicates the expansion side chamber R1 and the reservoir R in parallel with the expansion side passage 4, and the expansion side auxiliary passage 21a connects the expansion side chamber R1 and the compression side chamber R2 in parallel with the expansion passage 6. The pressure reservoir sub passage 21 b communicates with the pressure side chamber R 2 and the reservoir R in parallel with the pressure reservoir passage 7.

  That is, the expansion side auxiliary damping valve 20b is arranged in parallel with the expansion side damping valve 5, the pressure side auxiliary damping valve 21c is arranged in parallel with the compression side damping valve 8, and the reservoir side auxiliary damping valve 21d is similarly arranged in the reservoir side damping valve 9. Are arranged in parallel.

  In this embodiment, the expansion side sub-passage 20a and the pressure reservoir sub-passage 21b are converged by the converging passage 40 and communicated with the reservoir R, and convergence switching is performed in the middle of the converging passage 40. A valve 41 is provided. The convergence switching valve 41 shuts off both the expansion side sub-passage 20a and the pressure reservoir sub-passage 21b in a state where the convergence passage 40 is blocked, and the expansion side sub-passage 20a and the pressure reservoir in a state where the convergence passage 40 is opened. Both sub passages 21b are opened. That is, the convergence switching valve 41 has both functions of the extension side sub switching valve and the reservoir side sub switching valve. Thus, by providing the convergence passage 40, the function as the expansion side sub switching valve and the function as the reservoir side sub switching valve can be integrated into one convergence switching valve 41. Of course, it is possible to provide the extension side sub-switching valve and the reservoir side sub-switching valve independently without providing the convergence passage 40.

  The expansion side auxiliary damping valve 20b is a pressure proportional valve having the same configuration as that of the above-described expansion side damping valve 5, and opens when the pressure in the expansion side chamber R1 exceeds the valve opening pressure. Even if the R1 pressure is lower than the pressure in the reservoir R, it does not open and functions as a check valve. The expansion side auxiliary damping valve 20b is opened at the same valve opening pressure as that of the expansion side damping valve 5, and the proportionality of the flow path area to the pressure is set to be the same.

  Further, the pressure side auxiliary damping valve 21c is a pressure proportional valve having the same configuration as the pressure side damping valve 8 described above, and opens when the pressure in the pressure side chamber R2 exceeds the valve opening pressure, and the pressure side chamber R2 pressure. Even if the pressure is lower than the pressure in the extension side chamber R1, it does not open and functions as a check valve. The pressure side auxiliary damping valve 21c is opened at the same valve opening pressure as the pressure side damping valve 8, and the proportionality of the flow path area to the pressure is set to be the same.

  Similarly, the reservoir side auxiliary damping valve 21d is a pressure proportional valve having the same configuration as the reservoir side damping valve 9 described above, and opens when the pressure in the pressure side chamber R2 exceeds the valve opening pressure. At the same time, even if the pressure on the pressure side chamber R2 falls below the pressure in the reservoir R, it does not open and functions as a check valve. The reservoir side auxiliary damping valve 21d is opened at the same valve opening pressure as the reservoir side damping valve 9, and the proportionality of the flow path area to the pressure is set to be the same.

  Further, the convergence switching valve 41 and the pressure side sub switching valve 21e can be selectively switched between the communication position and the cutoff position by manual operation, but may be electromagnetic valves switched by a solenoid.

  When the convergence switching valve 41 and the pressure side auxiliary switching valve 21e are in the communication position, when the shock absorber D is extended, the hydraulic oil includes not only the expansion side damping valve 5 but also the expansion side auxiliary damping valve 20b arranged in parallel therewith. The oil passes through the expansion side chamber R1 and flows out to the reservoir R. When the shock absorber D is contracted, the hydraulic oil flows from the pressure side chamber R2 to the expansion side chamber R1 not only through the pressure side damping valve 8 but also through the pressure side auxiliary damping valve 21c. While moving, the pressure side chamber R2 flows to the reservoir R not only through the reservoir side damping valve 9 but also through the reservoir side sub damping valve 21d. On the other hand, when the convergence switching valve 41 and the pressure side sub switching valve 21e are set to the shut-off position, the hydraulic oil passes through the expansion side sub damping valve 20b, the pressure side sub damping valve 21c, and the reservoir side sub damping valve 21d when the shock absorber D expands and contracts. Without passing through, only the expansion side damping valve 5, the pressure side damping valve 8, and the reservoir side damping valve 9 are passed.

  That is, the convergence switching valve 41 and the pressure side sub switching valve 21e function as a switch that switches between exhibiting and stopping the damping function of the expansion side sub damping circuit 10a and the pressure side sub damping circuit 11a. Further, the extension side sub-attenuation circuit 10a and the pressure side sub-attenuation circuit 11a form a pair, and when the convergence switching valve 41 and the pressure side sub-switching valve 21e take the communication position, both exhibit the damping function, and conversely shut off. In position, the damping function is stopped.

  Note that the expansion side sub damping valve 20b, the pressure side sub damping valve 21c, and the reservoir side sub damping valve 21d in the expansion side sub damping circuit 10a and the compression side sub damping circuit 11a have the same piston speed of the shock absorber D, and are expanded and contracted. In order to generate the same damping force, the proportionality of the flow passage area to the valve opening pressure and pressure in the expansion side sub damping valve 20b, the pressure side sub damping valve 21c and the reservoir side sub damping valve 21d is adjusted.

  Further, the extension side sub-attenuation circuit 10b is provided in the middle of the extension side sub-passage 22a and the extension side sub-passage 22a for communicating the extension side chamber R1 and the reservoir R. The expansion side sub damping valve 22b for providing resistance and the convergence switching valve 43 functioning as an expansion side sub switching valve for opening and closing the expansion side sub passage 22a are configured. The compression side sub-attenuation circuit 11b includes a pressure expansion sub-passage 23a that connects the expansion-side chamber R1 and the pressure-side chamber R2, a pressure reservoir sub-passage 23b that connects the pressure-side chamber R2 and the reservoir R, and a middle of the pressure expansion sub-passage 23a. A pressure side auxiliary damping valve 23c that provides resistance to the flow of fluid from the pressure side chamber R2 to the expansion side chamber R1, and a fluid flow that is provided in the middle of the pressure reservoir sub passage 23b and flows from the pressure side chamber R2 to the reservoir R. Give resistance Functions as a reservoir side sub damping valve 23d, a pressure side sub switching valve 23e provided in the middle of the pressure expansion sub passage 21a to open and close the pressure expansion sub passage 23a, and a reservoir side sub switching valve to open and close the pressure reservoir sub passage 23b. And a convergence switching valve 43 to be configured.

  The extension side sub-passage 22a communicates the extension side chamber R1 and the reservoir R in parallel with the extension side passage 4 and the extension side sub passage 20a, and the pressure increase sub passage 23a includes the pressure increase passage 6 and the pressure extension sub passage 21a. The expansion side chamber R1 and the pressure side chamber R2 communicate with each other in parallel, and the pressure reservoir sub-passage 23b communicates with the pressure side chamber R2 and the reservoir R in parallel with the pressure reservoir passage 7 and the pressure reservoir sub-passage 21b.

  That is, the expansion side auxiliary damping valve 22b is arranged in parallel with the expansion side damping valve 5 and the extension side auxiliary damping valve 20b, and the pressure side auxiliary damping valve 23c is arranged in parallel with the pressure side damping valve 8 and the pressure side auxiliary damping valve 21c. Similarly, the side auxiliary damping valve 23d is arranged in parallel with the reservoir side damping valve 9 and the reservoir side auxiliary damping valve 21d.

  In this embodiment, the expansion side sub-passage 22a and the pressure reservoir sub-passage 23b are converged by the converging passage 42 and communicated with the reservoir R. Convergence switching is performed in the middle of the converging passage 42. A valve 43 is provided. The convergence switching valve 43 blocks both the expansion side sub-passage 22a and the pressure reservoir sub-passage 23b in a state where the convergence passage 42 is blocked, and the expansion side sub-passage 22a and the pressure reservoir in a state where the convergence passage 42 is opened. Both sub passages 23b are opened. That is, the convergence switching valve 43 has both functions of the extension side sub switching valve and the reservoir side sub switching valve. Thus, by providing the convergence passage 42, it is possible to consolidate the function as the expansion side sub switching valve and the function as the reservoir side sub switching valve into one convergence switching valve 43. Of course, it is possible to provide the extension side sub-switching valve and the reservoir side sub-switching valve independently without providing the convergence passage 42.

  The expansion side auxiliary damping valve 22b is a pressure proportional valve having the same configuration as the above-described expansion side attenuation valve 5 and expansion side auxiliary damping valve 20b, and opens at the same valve opening pressure as the expansion side attenuation valve 5. At the same time, the degree of proportionality of the channel area to the pressure is set to double.

  Further, the pressure side auxiliary damping valve 23c is a pressure proportional valve having the same configuration as the pressure side damping valve 8 and the pressure side auxiliary damping valve 21c described above, and is opened at the same valve opening pressure as that of the pressure side damping valve 8, and also with respect to the pressure. The proportionality of the channel area is set to double.

  Similarly, the reservoir side auxiliary damping valve 23d is a pressure proportional valve having the same configuration as the reservoir side damping valve 9 and the reservoir side auxiliary damping valve 21d, and has the same valve opening pressure as the reservoir side damping valve 9. And the proportionality of the channel area to the pressure is set to double.

  Further, the convergence switching valve 43 and the pressure side sub switching valve 23e can be selectively switched between the communication position and the shut-off position by manual operation, but may be electromagnetic valves switched by a solenoid.

  When the convergence switching valve 43 and the pressure side auxiliary switching valve 23e are in the communication position, when the shock absorber D is extended, the hydraulic oil includes not only the expansion side damping valve 5 but also the expansion side auxiliary damping valve 22b arranged in parallel therewith. The oil passes through the expansion side chamber R1 and flows out to the reservoir R. When the shock absorber D contracts, the hydraulic oil flows from the pressure side chamber R2 to the expansion side chamber R1 not only through the pressure side damping valve 8 but also through the pressure side auxiliary damping valve 23c. While moving, the pressure side chamber R2 flows to the reservoir R not only through the reservoir side damping valve 9 but also through the reservoir side sub damping valve 23d.

  On the other hand, when the convergence switching valve 43 and the pressure side sub switching valve 23e are set to the shut-off position, the hydraulic oil passes through the expansion side sub damping valve 22b, the pressure side sub damping valve 23c, and the reservoir side sub damping valve 23d when the shock absorber D expands and contracts. Without passing through, only the expansion side damping valve 5, the pressure side damping valve 8, and the reservoir side damping valve 9 are passed.

  That is, the convergence switching valve 43 and the pressure side sub switching valve 23e function as a switch that switches between exhibiting and stopping the damping function of the expansion side sub damping circuit 10b and the pressure side sub damping circuit 11b. The expansion side sub-attenuation circuit 10b and the pressure side sub-attenuation circuit 11b are paired in the same manner as the expansion side sub-attenuation circuit 10a and the pressure side sub-attenuation circuit 11a, and the convergence switching valve 43 and the pressure side sub-switching valve 23e communicate with each other. Both take their positions when they are in position, and on the other hand they stop their functions at the blocking position.

  The expansion side sub damping valve 22b, the pressure side sub damping valve 23c, and the reservoir side sub damping valve 23d in the expansion side sub damping circuit 10b and the compression side sub damping circuit 11b also expand and contract when the piston speed of the shock absorber D is the same. The degree of proportionality of the flow passage area to the valve opening pressure and pressure in the expansion side sub damping valve 22b, the pressure side sub damping valve 23c, and the reservoir side sub damping valve 23d is adjusted so that the same damping force can be generated.

  The shock absorber D is configured as described above, and the operation thereof will be described below.

  (1) First, when the convergence switching valves 41 and 43 and the pressure side auxiliary switching valves 21e and 23e are both in the cut-off position and the extension side auxiliary damping circuits 10a and 10b and the pressure side auxiliary damping circuits 11a and 11b do not function, the buffer D The expansion side damping force of the shock absorber D is caused by the hydraulic oil passing through the expansion side damping valve 5, while the compression side damping force of the shock absorber D is caused by the hydraulic oil passing through the compression side damping valve 8 and the reservoir side damping valve 9. As shown by the solid line in FIG. 2, when the piston speed is the same, the generated damping force becomes equal on the expansion side and the compression side, and increases in proportion to the piston speed. In this shock absorber D, the hydraulic fluid passes only through the expansion side damping valve 5 when extended, and only passes through the compression side damping valve 8 and the reservoir side damping valve 9 when contracted. The coefficient is the maximum. In FIG. 2, the line of the damping characteristic indicated by the solid line (in which the change in damping force with respect to the piston speed is changed) is bent halfway. This is because the expansion side relief valve 16 and the pressure side are changed at the inflection point. This is because the relief valve 17 is opened and an increase in damping force is suppressed. Further, when the piston speed is 0, the damping force is generated because the piston 2 does not move until the expansion side damping valve 5, the pressure side damping valve 8 and the reservoir side damping valve 9 are opened. This is because a force that resists this is generated.

  (2) Subsequently, the convergence switching valve 41 and the pressure side auxiliary switching valve 21e are in the communication position, the convergence switching valve 43 and the pressure side auxiliary switching valve 23e are in the cutoff position, and the extension side auxiliary damping circuit 10a and the pressure side auxiliary damping circuit 11a. However, when the expansion side sub-attenuation circuit 10b and the compression side sub-attenuation circuit 11b do not function, the expansion side damping force of the shock absorber D causes the hydraulic oil to pass through the expansion side attenuation valve 5 and the expansion side auxiliary attenuation valve 20b. On the other hand, the pressure side damping force of the shock absorber D is generated by the hydraulic oil passing through the pressure side damping valve 8, the pressure side auxiliary damping valve 21c, the reservoir side damping valve 9 and the reservoir side auxiliary damping valve 21d, and is generated. As indicated by a broken line in FIG. 2, when the piston speed is the same, the damping force becomes equal on the expansion side and the compression side, and increases in proportion to the piston speed. In this case, as compared with the case where only the expansion side damping valve 5, the pressure side damping valve 8 and the reservoir side damping valve 9 are passed, the hydraulic oil is expanded side auxiliary damping valve 20b, pressure side auxiliary damping valve 21c and reservoir side auxiliary damping valve. Since it also passes through 21d, the flow path area is doubled and the attenuation coefficient is halved. In FIG. 2, the reason why the line of the damping characteristic indicated by the broken line is bent in the middle is that, as described above, the expansion side relief valve 16 and the pressure side relief valve 17 are opened, and the piston speed is 0. At this time, the damping force is generated as described above.

  (3) Subsequently, the convergence switching valve 41 and the pressure side auxiliary switching valve 21e are set to the shut-off position, the convergence switching valve 43 and the pressure side auxiliary switching valve 23e are in the communication position, and the expansion side auxiliary damping circuit 10a and the pressure side auxiliary damping circuit 11a. Does not function, but when the expansion side sub-attenuation circuit 10b and the compression side sub-attenuation circuit 11b function, the expansion side damping force of the shock absorber D passes through the expansion side attenuation valve 5 and the expansion side auxiliary attenuation valve 22b. On the other hand, the pressure side damping force of the shock absorber D is generated by the hydraulic oil passing through the pressure side damping valve 8, the pressure side auxiliary damping valve 23c, the reservoir side damping valve 9 and the reservoir side auxiliary damping valve 23d, and is generated. As indicated by a one-dot chain line in FIG. 2, when the piston speed is the same, the damping force becomes equal on the expansion side and the compression side, and increases in proportion to the piston speed. In this case, compared with the case where only the expansion side attenuation valve 5, the pressure side attenuation valve 8 and the reservoir side attenuation valve 9 are passed, the hydraulic oil is expanded side auxiliary attenuation valve 22b, pressure side auxiliary attenuation valve 23c and reservoir side auxiliary attenuation valve. 23d is also passed, so the flow path area is tripled and the attenuation coefficient is one third. In FIG. 2, the reason why the line of the damping characteristic indicated by the broken line is bent in the middle is that, as described above, the expansion side relief valve 16 and the pressure side relief valve 17 are opened, and the piston speed is 0. At this time, the damping force is generated as described above.

  (4) Further, when the convergence switching valves 41 and 43 and the pressure side auxiliary switching valves 21e and 23e are both in the communication position and the extension side auxiliary damping circuits 10a and 10b and the pressure side auxiliary damping circuits 11a and 11b function together, the shock absorber The extension side damping force of D is generated by the hydraulic oil passing through the extension side damping valve 5, the extension side auxiliary damping valve 20b, and the extension side auxiliary damping valve 22b, while the compression side damping force of the shock absorber D is the hydraulic oil. Is caused by passing through the pressure side damping valve 8, the pressure side secondary damping valve 21c, the pressure side secondary damping valve 23c, the reservoir side damping valve 9, the reservoir side secondary damping valve 21d and the reservoir side secondary damping valve 23d, and the generated damping force is As indicated by a two-dot chain line in FIG. 2, when the piston speed is the same, the expansion side and the compression side are equal and increase in proportion to the piston speed. In this case, compared with the case where only the expansion side damping valve 5, the pressure side attenuation valve 8 and the reservoir side attenuation valve 9 are passed, the hydraulic oil is expanded side auxiliary damping valve 20b, extension side auxiliary damping valve 22b, pressure side auxiliary damping valve. 21c, the pressure side auxiliary damping valve 23c, the reservoir side auxiliary damping valve 21d and the reservoir side auxiliary damping valve 23d are also passed through, so that the flow path area is quadrupled and the damping coefficient is reduced to a quarter. In FIG. 2, the reason why the line of the damping characteristic indicated by the broken line is bent in the middle is that, as described above, the expansion side relief valve 16 and the pressure side relief valve 17 are opened, and the piston speed is 0. At this time, the damping force is generated as described above.

  As described above, in the shock absorber D, even if the bi-flow is set, the extension side sub-attenuation circuits 10a and 10b and the compression side sub-attenuation circuits 11a and 11b are selectively functioned as a pair, thereby reducing the damping force. Can be made variable.

  In the shock absorber D, the hydraulic oil as the fluid in the expansion side chamber R1 is compressed during expansion, and the hydraulic oil in the compression side chamber R2 is compressed instead of the entire cylinder 1 during contraction. As can be seen, the amount of fluid compressed at the time of expansion and contraction does not differ significantly, and a damping valve that operates on the expansion side and the contraction side is set. In this embodiment, the expansion side damping valve 5 and the pressure side damping valve 8. It is possible to generate a damping force as intended in the buffer D by setting the reservoir side damping valve 9, the extension side subsidiary damping valves 20b and 22b, the pressure side subsidiary damping valves 21c and 23c, and the reservoir side subsidiary damping valves 21d and 23d. In addition, if each damping valve is set as described above as in this embodiment, the damping force can be made to exert equal damping force on both sides of the expansion and contraction if the piston speed is the same. .

  In other words, in this shock absorber D, since the damping force can be made variable and the biflow can be adopted while exhibiting the desired damping force on both sides of the expansion and contraction, the amount of fluid compressed during expansion and contraction can be reduced. Since it can be made relatively small, a damping force can be sufficiently exerted even with respect to a minute vibration with a very small expansion / contraction amount.

  Further, since the shock absorber D is set to biflow, there is no restriction on the relationship between the piston cross-sectional area and the rod cross-sectional area, the design freedom of the shock absorber D increases, and the piston diameter or rod diameter. However, there is no inconvenience that the diameter becomes unnecessarily large in terms of strength, so that the buffer is not increased in size and weight.

  Further, when the damping force in the shock absorber D is made variable, the expansion side damping valve 5, the pressure side damping valve 8, the reservoir side damping valve 9, the stretching side sub damping valves 20b and 22b, and the pressure side sub damping valve 21c are switched instead of switching the expansion / contraction operation. , 23c and the reservoir side auxiliary damping valves 21d, 23d need not be selected each time, so that there is no need for a large-scale control device, and in this respect as well, an increase in the size of the entire system including the buffer D can be avoided. .

  Further, in the shock absorber D, the expansion side damping valve 5, the expansion side sub damping valves 20b and 22b, the pressure side damping valve 8, the pressure side sub damping valves 21c and 23c, the reservoir side damping valve 9 and the reservoir side sub damping valve 21d. , 23d are pressure proportional valves, so that the damping coefficient can be made variable. In addition, this makes it possible to secure a change range of the damping force even with a minute vibration with a very small expansion / contraction amount.

  Further, the extension side damping valve 5, the extension side auxiliary damping valves 20b and 22b, the pressure side damping valve 8, the pressure side auxiliary damping valves 21c and 23c, the reservoir side damping valve 9 and the reservoir side auxiliary damping valves 21d and 23d are used as check valves. Is also functioning, and a separate check is provided in each of the expansion side passage 4, the pressure side passage 6, the pressure reservoir passage 7, the expansion side sub passages 20a and 22a, the pressure expansion sub passages 21a and 23a, and the pressure reservoir sub passages 21b and 23b. Since it is not necessary to provide a valve, unnecessary increase in size of the shock absorber D is prevented in this respect as well.

In this case, since the two pairs of the extension side sub-attenuation circuits 10a and 10b and the compression side sub-attenuation circuits 11a and 11b are provided, the damping force can be changed in four ways. If the number of pairs of sub-damping circuits is increased, the change pattern of the damping force can be further increased. For example, if the number of pairs is n, the change pattern of the damping force is ²ⁿ .

  Next, the shock absorber D 'in a modification of the embodiment shown in FIG. 3 will be described. The shock absorber D ′ includes a plurality of pressure side damping valves 8, reservoir side damping valves 9, pressure side auxiliary damping valves 21 c and 23 c, and reservoir side auxiliary damping valves 21 d and 23 d of the buffer D according to the embodiment. Fixed orifices 51, 52, 53, 54, 55, 56 are provided.

  In addition, check valves 57 and 58 that permit only a flow from the pressure side chamber R2 to the reservoir R are arranged in series with respect to the fixed orifices 54 and 56 that are arranged in parallel with the reservoir side auxiliary damping valves 21d and 23d, respectively. The hydraulic oil that has passed through the extension side auxiliary damping valves 20b and 22b during the extension of the shock absorber D ′ is prevented from passing through the fixed orifices 54 and 56 and flowing into the compression side chamber R2 from the extension side chamber R1.

  Further, when the expansion side sub switching valve and the reservoir side sub switching valve are provided independently without providing the convergence passages 40, 42, the check valves 57, 58 may not be provided.

  By providing the fixed orifices 51, 52, 53, 54, 55, and 56 in the shock absorber D 'in this way, the damping characteristic line at the rising of the damping force with respect to the piston speed during expansion and contraction becomes a square characteristic. It becomes possible to set. Here, the fixed orifices corresponding to the extension side damping valve 5 and the extension side auxiliary damping valves 20b, 22b are not arranged in parallel. However, when the extension side is extended, the hydraulic oil passes through the fixed orifices 51, 53, 55. Since it passes through and moves from the expansion side chamber R1 to the compression side chamber R2, the line of the damping characteristic at the rise of the damping force with respect to the piston speed on the expansion side also becomes the square characteristic that is the orifice characteristic. It is not necessary to arrange a fixed orifice in parallel with each of the damping valves 20b and 22b, and equal damping force can be generated on both sides of expansion and contraction by setting the fixed orifices 51, 52, 53, 54, 55 and 56. .

  In addition to the above configuration, a fixed orifice may be provided in parallel with each of the expansion side damping valve 5 and the expansion side auxiliary damping valves 20b and 22b. Further, the fixed orifice may be expanded by the damping force required for the shock absorber D ′. Fixed to any one of the side damping valve 5, the extension side sub damping valve 20b, 22b, the pressure side damping valve 8, the reservoir side damping valve 9, the pressure side sub damping valve 21c, 23c and the reservoir side sub damping valve 21d, 23d. Orifices may be arranged in parallel.

  In each of the embodiments, the extension side sub-passages 20a and 22a in the extension side passage 4 and the extension side auxiliary attenuation circuits 10a and 10b are configured to communicate the extension side chamber R1 and the reservoir R as described above. However, the extension side chamber R1 and the compression side chamber R2 may communicate with each other. In this case, the hydraulic oil moves from the expansion side chamber R1 to the pressure side chamber R2 when the expansion operation is performed, but the pressure side chamber R2 is operated for the volume of the rod 4 leaving the cylinder 1 through the suction passage 18 from the reservoir R. Since the oil supply is received, the pressure side chamber R2 has the same pressure as the inside of the reservoir R. Therefore, the operation is exactly the same as the above-described shock absorbers D and D ′. Therefore, when the extension side chamber R1 and the compression side chamber R2 are communicated with each other by the extension side passage 4 and the extension side sub passages 20a and 22a, these passages may be provided in the piston 2.

  Further, in the drawing, the expansion side sub-attenuation circuits 10a and 10b and the compression side sub-attenuation circuits 11a and 11b have the expansion side attenuation valve 5, the expansion side auxiliary attenuation valves 20b and 22b, the compression side attenuation valve 8, the reservoir side attenuation valve 9, The pressure side auxiliary damping valves 21c and 23c, the reservoir side auxiliary damping valves 21d and 23d, the pressure side auxiliary switching valves 21e and 23e, and the convergence switching valves 41 and 43 are provided on the outer side of the cylinder 1. Of course, it may be installed inside the bottom member 13.

  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.

It is a circuit diagram in the buffer in one embodiment. It is an attenuation characteristic figure of a buffer in one embodiment. It is a circuit diagram in the buffer in one modification of one embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Rod 4 Extension side channel | path 5 Extension side damping valve 6 Extension pressure passage 7 Pressure reservoir passage 8 Pressure side damping valve 9 Reservoir side damping valve 10a, 10b Extension side auxiliary damping circuit 11a, 11b Pressure side auxiliary damping circuit 12 Head member 13 Bottom member 14, 15 Relief channel 16 Stretch side relief valve 17 Pressure side relief valve 18 Suction passage 19, 57, 58 Check valve 20a, 22a Stretch side sub passage 20b, 22b Stretch side sub damping valve 21a, 23a Stretch side Passages 21b, 23b Pressure reservoir sub-passages 21c, 23c Pressure-side sub-damping valves 21d, 23d Reservoir-side sub-damping valves 21e, 23e Pressure-side sub-switching valves 40, 42 Converging passages 41, 43 Converging switching valves 51, 52, 53, 54, 55 , 56 Fixed orifice D, D 'Buffer R Reservoir R1 Extension side chamber R2 Pressure side chamber

Claims (4)

A cylinder, a piston that is slidably inserted into the cylinder and that divides the cylinder into an extension side chamber and a pressure side chamber, a rod that is movably inserted into the cylinder and has one end connected to the piston, and a reservoir An extension side passage that communicates between the extension side chamber and the reservoir or the compression side chamber, and an extension side damping valve that is provided in the middle of the extension side passage and that provides resistance to the flow of fluid from the extension side chamber toward the reservoir or the pressure side chamber; A pressure-side damping that provides resistance to the flow of fluid from the pressure-side chamber to the extension-side chamber, provided in the middle of the pressure-reduction passage, and a pressure-retention passage that communicates the pressure-side chamber with the pressure-side chamber In a shock absorber comprising a valve and a reservoir-side damping valve that is provided in the middle of the pressure reservoir passage and provides resistance to the flow of fluid from the pressure-side chamber toward the reservoir, a pair of expansion-side sub-attenuation circuit and pressure-side At least one pair of damping circuits is provided, and the extension side sub-attenuation circuit is provided in the middle of the extension side sub passage and the extension side sub passage from the extension side chamber to the reservoir or pressure side chamber. An expansion side sub-damping valve that provides resistance to the flow of the fluid to be directed, and an expansion side sub-switching valve that is provided in the middle of the expansion side sub-passage to open and close the expansion side sub-passage. A pressure expansion sub-passage that communicates with the pressure side chamber, a pressure reservoir sub-passage that communicates the pressure side chamber and the reservoir, and a resistance provided to the flow of fluid from the pressure side chamber toward the expansion side chamber. A pressure side auxiliary damping valve, a reservoir side auxiliary damping valve that is provided in the middle of the pressure reservoir auxiliary passage and resists the flow of fluid from the pressure side chamber toward the reservoir, and a pressure extension auxiliary passage that is provided in the middle of the pressure extension auxiliary passage Pressure side sub-switching valve for opening and closing and pressure reservoir sub-passage Shock absorber, characterized by comprising a reservoir collateral control valve for opening and closing the pressure reservoir sub passage provided in the middle of the. A converging passage that connects the expansion side sub-passage and the pressure reservoir sub-passage in the pair of extension side sub-attenuation circuit and pressure side sub-attenuation circuit to the reservoir is provided, and a convergence switching valve that opens and closes the convergence passage is provided in the middle of the convergence passage 2. The shock absorber according to claim 1, wherein the convergence switching valve serves as an expansion side sub switching valve and a reservoir side sub switching valve. The fixed orifice is arranged in parallel with any one of the expansion side damping valve, the pressure side damping valve, the reservoir side damping valve, the stretching side sub damping valve, the pressure side sub damping valve, and the reservoir side sub damping valve. Or the shock absorber according to 2. 4. The expansion side damping valve, the pressure side damping valve, the reservoir side damping valve, the stretching side secondary damping valve, the pressure side secondary damping valve, and the reservoir side secondary damping valve are pressure proportional valves, respectively. A shock absorber according to the above.

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