JP2006132554A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber that can be easily assembled and can reduce the number of processing steps, and another object is to prevent a reduction in strength of the shock absorber.
A damping force adjusting mechanism is slidably inserted into a hollow portion 33 formed in a flow path 10, and thrust is given by a solenoid S provided at the other end of a piston rod 3 and an upper flow path 11 is provided. The spool 50 is provided with thrust in a direction opposite to the thrust of the solenoid S by pressure. The spool 50 has land portions 51 and 52 formed at both ends thereof, and the one land portion 51 is opened to the outlet of the upper flow path 11. The other land portion 52 is opposed to the inlet opening of the lower flow path 12 and the thrust force of the solenoid S is changed, whereby the outlet opening area of the upper flow path 11 and the inlet opening area of the lower flow path 12 are changed. Adjust the damping force by changing.
[Selection] Figure 1

Description

  The present invention relates to an improvement of a shock absorber that can change a damping force using a solenoid.

  Conventionally, as this type of shock absorber, for example, a cylinder filled with so-called hydraulic oil, a piston that is slidably inserted into the cylinder and divides the cylinder into an upper chamber and a lower chamber, and one end of the piston is the piston. And a piston rod whose other end extends to the outside of the cylinder, and a valve whose cracking pressure is controlled by the thrust of a solenoid provided in the piston. In other words, the flow path is arranged so that the hydraulic oil always passes through the valve from one direction when the hydraulic oil moves from a high pressure chamber to a low pressure chamber of the upper chamber or the lower chamber by expansion and contraction.

The valve includes a valve seat and a poppet type valve body provided in the middle of the flow path, a spring for biasing the poppet type valve body in the valve seat direction, and a solenoid for increasing or decreasing the biasing force of the spring. It is possible to change the damping force if the cracking pressure is controlled by this solenoid (see, for example, Patent Document 1).
JP 04-262134 A (page 3, right column, line 35 to page 5, right column, line 24, FIG. 1)

  However, although there is no functional problem with the above-described shock absorber, it may be pointed out that it may cause the following problems.

  That is, in the conventional shock absorber, since the piston part has a built-in solenoid, it takes time to assemble the shock absorber, and the accuracy of the coaxiality of the piston rod and the piston may be insufficient. Since the poppet valve is adopted, there is a possibility that the accuracy of the coaxiality at this portion may be insufficient, and the assembly work is inevitably complicated if sufficient accuracy is to be ensured.

  Moreover, since the solenoid is incorporated in the piston portion, the strength of the cylindrical member connecting the piston rod and the piston may be reduced.

  Accordingly, the present invention has been developed to improve the above-described problems, and the object of the present invention is to provide a shock absorber that is particularly easy to assemble and can reduce the number of processing steps. The purpose of is to prevent a decrease in the strength of the shock absorber.

  In order to achieve the above-mentioned object, a cylinder, a piston rod having a piston portion slidably inserted into the cylinder at one end, one chamber and the other chamber separated by the piston portion in the cylinder, In the shock absorber provided with a flow path communicating between the one chamber and the other chamber provided in the piston section and a damping force adjusting mechanism provided in the middle of the flow path, the flow path is formed in the piston section. A hollow part, an upper flow path that allows only a liquid flow from the high pressure side to the hollow part of one chamber and the other chamber, and a liquid flow only from the hollow part to the low pressure side of the one chamber and the other chamber. The damping force adjusting mechanism is slidably inserted into the hollow portion, thrust is given by a solenoid provided at the other end of the piston rod, and the direction facing the solenoid thrust by the pressure in the upper channel The thrust that is given The spool has land portions formed at both end sides thereof, one land portion being opposed to the outlet opening portion of the upper flow path and the other land portion being opposed to the inlet opening portion of the lower flow path. By changing the thrust of the solenoid, the damping force is adjusted by changing the outlet opening area of the upper flow path and the inlet opening area of the lower flow path.

  According to the present invention, the solenoid is not provided in the piston portion but is provided in the other end of the piston rod, so that the strength of the piston portion is not reduced unnecessarily. Since the assembly of this is the same assembly as a normal hydraulic shock absorber, the accuracy of the coaxiality does not become insufficient, and sufficient accuracy can be secured without performing complicated assembly work. The number of man-hours for assembly is reduced.

  In addition, since the spool is used, the assembling work becomes very simple as compared to the poppet valve that needs to be assembled while ensuring the accuracy of the coaxiality, and there is no problem of ensuring the coaxiality.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a shock absorber according to an embodiment of the present invention. FIG. 2 is a partially enlarged longitudinal sectional view of the shock absorber according to the embodiment of the present invention. FIG. 3 is a partially enlarged longitudinal sectional view of a shock absorber according to another embodiment of the present invention.

  As shown in FIG. 1, the shock absorber includes a cylinder 1, a piston 2 slidably inserted into the cylinder 1, a piston rod 3 having one end connected to the piston 2, and the piston in the cylinder 1. 2, one chamber R 1 and the other chamber R 2, a free piston F that is slidably inserted into the cylinder 1 and divides the cylinder 1 into the other chamber R 2 and the air chamber G, and a piston 2 and a piston rod 3. It is comprised by the flow path 10 which connects one chamber R1 and the other chamber R2 which were provided in the piston part P comprised as one end part of this, and the damping-force adjustment mechanism provided in the middle of this flow path 10.

  In this shock absorber, when the piston rod 3 moves up and down with respect to the cylinder 1, that is, when the shock absorber expands and contracts, the one chamber R1 moves to the other chamber R2 or the other chamber R2 moves to the one chamber R1. When a fluid such as hydraulic fluid moves, a damping force is generated by the damping force adjusting mechanism, and the hydraulic fluid that becomes excessive or insufficient in volume when the piston rod 3 moves in and out of the cylinder 1 is a free piston F. It is compensated by the expansion or contraction of the gas in the separated air chamber G.

  In other words, this shock absorber is configured as a so-called single-cylinder hydraulic shock absorber, as illustrated. As another type of shock absorber, a so-called multi-cylinder type in which an outer cylinder is provided outside the cylinder 1 and a reservoir having an air chamber is provided in a gap between the cylinder 1 and the outer cylinder. Alternatively, the reservoir may be separated from the buffer and formed elsewhere, and the one chamber R1 or the other chamber R2 in the cylinder 1 and the reservoir may be connected by a pipe line.

  Hereinafter, each part of the shock absorber will be described in detail with reference to FIGS. 1 and 2. As described above, the piston part P is formed by the piston 2 and one end part of the piston rod 3, and the piston 2 is an annular piston. A main body 21 and an annular valve disk 22 disposed below the piston main body 21 in FIG. 2 are provided, and the piston main body 21 and the valve disk 22 are fitted into a reduced diameter portion 31 formed at one end of the piston rod 3. It is inserted and fixed by a piston nut 32 that is screwed to the lowermost end of the piston rod 3.

  Note that a spacer 65 and a laminated spacer 66 are interposed between the valve disk 22 and the piston body 21, and a chamber A is separated between the valve disk 22 and the piston body 21.

  And the flow path 10 is formed in the piston main body 21 used as the piston part P, and the one end part of the piston rod 3, but this flow path 10 is the hollow part 33 formed in the one end part of the piston rod 3, and The upper flow passage 11 that allows only the flow of hydraulic fluid from the high pressure side to the hollow portion 33 in the one chamber R1 and the other chamber R2, and the hydraulic fluid from the hollow portion 33 to the low pressure side in the one chamber R1 and the other chamber R2. The upper flow path 11 further includes a communication path 111 that communicates the one chamber R1 and the other chamber R2, and a connection path that communicates the communication path 111 and the hollow portion 33. 112, and the other lower flow path 12 also includes a communication path 121 that communicates the one chamber R1 and the other chamber R2, and a connection path 122 that communicates the communication path 121 and the hollow portion 33. It is configured.

  An annular groove 211 and an annular groove 212 are formed on the inner peripheral side of the piston main body 21 so as to be arranged vertically. The annular groove 211 is formed wider than the annular groove 212 and is formed in the upper flow path 11. Further, the annular groove 212 is communicated with the connection path 122 of the lower flow path.

  Further, the piston rod 3 is hollow in the whole axial direction, that is, in a cylindrical shape, and the inside of the reduced diameter portion 31 formed at one end thereof is a hollow portion 33, and the hollow portion 33 is It is arranged at a position just opposite to the piston main body 21.

  A plurality of ports 35, 36, and 37 that communicate with the hollow portion 33 and the outside of the reduced diameter portion 31 of the piston rod 3 are vertically arranged and opened at the side of the reduced diameter portion 31. When the piston main body 21 and the piston rod 3 are assembled, the port 35 and the port 36 are set to face the annular groove 211, respectively, and the port 37 is set to face the annular groove 212.

  That is, the hollow portion 33 is communicated with the upper flow path 11 via the ports 35 and 36 and the annular groove 211, and is communicated with the lower flow path 12 via the port 37 and the annular groove 212.

  In addition, without providing the annular groove 211 and the annular groove 212, the connection path 112 and the connection path 122 may be directly connected to the ports 35, 36, and 37 so that the above-described flow paths are formed. By providing the annular grooves 211 and 212, the troublesome work of positioning when the piston main body 21 is assembled to the piston rod 3 can be omitted, which is convenient.

  Further, pipes 42 and 43 are fitted in the upper and lower portions of the upper passage 11 in the communication passage 111 except for the connection portion with the connection passage 112, and a ball having a diameter larger than the inner diameter of the pipes 42 and 43. When one of the one chamber R1 and the other chamber R2 has a high pressure, for example, when the pressure on the one chamber R1 side becomes higher than the pressure on the other chamber R2 side, the ball 44 moves downward in FIG. When the upper end opening of the pipe 43 is pushed down to allow communication between the one chamber R1 and the hollow portion 33, conversely, the pressure on the other chamber R2 side becomes higher than the pressure on the one chamber R1 side. The ball 44 is pushed upward in FIG. 2 to close the lower end opening of the pipe 42 and allow the other chamber R2 and the hollow portion 33 to communicate with each other.

  That is, the ball 44 provided in the communication path 111 functions as a high pressure priority shuttle valve.

  When the upper flow path 11 and the lower flow path 12 are formed in the piston body 21, as shown in the figure, the communication path 111 and the communication path 121 are drilled in the axial direction with respect to the piston body 21, and the connection path 112 and the connection path are connected. By drilling the passage 122 in the piston body 21 from the radial direction, the upper flow path 11 and the lower flow path 12 can be easily provided in the piston main body 21.

  Further, regarding the high-pressure priority shuttle valve, it is not necessary to adopt the above-described configuration. However, by adopting the above-described configuration, in addition to the formation of the upper flow path 11, the assembly of the pipes 42 and 43 and the ball 44 This is advantageous in that the high-pressure priority shuttle valve can be provided in the piston body 21 by a simple operation of insertion into the communication passage 111.

  On the other hand, the open end on the one chamber R1 side of the communication path 121 in the lower flow path 12 is closed by an annular plate valve 45 stacked on the upper end in FIG. 2 of the piston body 21 and stacked on the lower end in FIG. The plate valve 45 and the plate valve 46 are inserted into the reduced diameter portion 31 of the piston rod 3 and fixed by the piston nut 32, as in the piston main body 21.

  The plate valve 45 acts as a check valve that blocks the flow of hydraulic oil from the one chamber R1 to the lower flow path 12, and when the pressure on the lower flow path 12 side is greater than the pressure on the one chamber R1 side, The hydraulic oil in the passage 12 is allowed to move into the one chamber R1 by opening the one valve R1 side of the communication passage 121 by bending the plate valve 45 upward in FIG.

  Further, the plate valve 46 acts as a check valve that blocks the flow of hydraulic oil from the other chamber R2 to the lower flow path 12, and when the pressure on the lower flow path 12 side is larger than the pressure on the other chamber R2 side, The hydraulic oil in the passage 12 is allowed to move into the other chamber R2 by opening the other chamber R2 side of the communication passage 121 by bending the plate valve 46 downward in FIG.

  In addition, since the holes 47 and 48 are opened in the portions of the upper flow passages 11 of the plate valves 45 and 46 facing the communication passage 111, the plate valves 45 and 46 are opened in the one chamber R1 or the other chamber R2. Therefore, the flow of hydraulic oil from the upper flow path 11 to the upper flow path 11 is not hindered.

  As described above, by using the high-pressure priority shuttle valve in the upper flow path 11, it is not necessary to make the piston part P in a complicated shape as compared to the case of using only the check valve as in the conventional shock absorber. A piston body having substantially the same shape as the used piston shape can be employed, and the piston body can be manufactured at low cost.

  In turn, a spool 50 is slidably inserted into a hollow portion 33 formed in one end portion of the piston rod 3, and the spool 50 has land portions on both upper and lower ends in FIG. 51, 52 are formed, and the land portion 51 is opposed to the port 36 for opening the piston rod 3, and the land portion 52 is opposed to the port 37 for opening the piston rod 3.

  Further, a stopper 38 is provided in the lower end portion in FIG. 1 of the reduced diameter portion 31 of the piston rod 3, whereby the hollow portion 33 is isolated from the other chamber R 2, and the hollow portion 33 is separated by the spool 50. A pressure chamber B is separated, and the pressure chamber B is connected to the port 35, and the pressure in the upper flow path 11 guided into the pressure chamber B can act on the lower end surface of the spool 50 as a pressure receiving surface. Thus, a thrust can be applied to the spool 50 in the upward direction in FIG.

  Further, a spring 53 is accommodated in the pressure chamber B, and this spring 53 is interposed between the lower end of the spool 50 and the upper end of the stopper 38, so that the spool 50 is attached upward in FIG. To force.

  Furthermore, the lower end of the control rod 54 inserted into the piston rod 3 is brought into contact with the upper end of the spool 50, and the upper end of the control rod 54 is connected to the other end of the piston rod 3 as shown in FIG. 1 is connected to the movable iron core 60 of the solenoid S fixed to the upper end in FIG.

  A spring 62 is interposed between the upper end of the movable iron core 60 and the case 61 of the solenoid S, and a stator 63 composed of a winding and a core is provided on the outer peripheral side of the movable iron core 60. When 63 windings are excited, a thrust can be applied to the movable iron core 60 downward in FIG.

  Accordingly, when the winding in the solenoid S is excited, a thrust can be applied to the spool 50 via the control rod 54 in the direction of pushing down in FIG.

  The spool 50 does not excite the winding of the solenoid S, and the land portion 51 and the land portion 52 completely close the port 36 and the port 37, respectively, at a position where only the spring force of the spring 53 and the spring 62 is balanced. First, the lap area of the port 36 and the land portion 51 and the lap area of the port 37 and the land portion 52 are set to be approximately the same, and the position of the spool 50 is controlled by the magnitude of the current exciting the winding. Thus, the lap area between the land portion 51 and the port 36 and the lap area between the land portion 52 and the port 37 can be controlled.

  Then, by controlling the position of the spool 50, the lap area is increased or decreased to adjust the opening area of the port 36, that is, the outlet opening area of the upper flow path 11, and the opening area of the port 37, that is, the inlet opening area of the lower flow path 12. This makes it possible to adjust the damping force. That is, in the present embodiment, the damping force adjustment mechanism is configured by the spool 50 and the solenoid S.

  On the other hand, the valve disk 22 fixed below the piston body 21 is fitted to the annular body 221, the outer peripheral side of the annular body 221, and in sliding contact with the inner periphery of the cylinder 1, and the cylindrical part 222. 1 is formed with an annular fixing member 223 screwed to the lower inner peripheral side in FIG. 1, and the annular main body 221 includes a step portion (not shown) formed on the inner peripheral side of the cylindrical portion 222 and a fixing member 223. Is sandwiched between.

  Further, the annular main body 221 is provided with a plurality of ports 23 that communicate with the space A and the other chamber R2 in the axial direction, and an annular leaf valve 24 is formed on the outer peripheral side of the upper end of the annular main body 221 in FIG. Further, the inner peripheral side of the annular leaf valve 24 is in contact with the lower surface side of the laminated spacer 66, and the port 23 is provided by the annular leaf valve 24. The outlet end on the space A side is closed.

  Further, a cap-shaped valve stopper 25 is provided on the outer peripheral side of the upper end of the annular main body 221 of the valve disk 22, and the valve stopper 25 is notched so that the space A and the other chamber R 2 can communicate with each other. Is formed, and a hole (not shown) is provided in the axial center portion so that the reduced diameter portion 31 of the piston rod 3 can be inserted, and is sandwiched between the spacer 65 and the laminated spacer 66. This is fixed to the piston rod 3.

  When the pressure on the space A side is larger than the pressure on the other chamber R2 side, the annular leaf valve 24 is bent downward in FIG. 1 to create a gap with the laminated spacer 66. The oil can move from the space A to the other chamber R <b> 2, and a damping force is generated by a pressure loss generated when the hydraulic oil passes between the laminated spacer 66 and the annular leaf valve 24.

  On the other hand, when the pressure on the other chamber R2 side is larger than the pressure on the space A side, the outer peripheral side of the annular leaf valve 24 bends upward in FIG. 1 and separates from the valve seat 224, and the annular leaf valve 24 and the valve seat 224 The hydraulic fluid can move from the other chamber R2 to the space A and is attenuated by the pressure loss generated when the hydraulic fluid passes between the annular leaf valve 24 and the valve seat 224. Generate power.

  That is, in the present embodiment, it is possible to generate the damping force by the annular leaf valve 24 separately from the above-described damping force adjusting mechanism.

  In the shock absorber configured as described above, when the piston rod 3 moves upward with respect to the cylinder 1, the volume of the one chamber R1 decreases and the volume of the other chamber R2 decreases. Since it increases, the pressure of the hydraulic oil in one chamber R1 becomes higher than that in the other chamber R2.

  Then, since the ball 44 in the communication path 111 in the upper flow path 11 is pressed against the pipe 43 side, the hollow portion 33 and the one chamber R1 are in communication with each other, and the hydraulic oil in the one chamber R1 flows into the upper flow path 11. Then, it passes through the annular groove 211 and the port 36 and flows into the hollow portion 33, and passes through the upper flow path 11, the annular groove 211 and the port 35 and flows into the pressure chamber B.

  Since the spool 50 is thrust upward in FIG. 2 due to the pressure increase in the pressure chamber B, the lap area between the port 36 and the land portion 51 increases, and the opening area of the port 36 tends to decrease, The lap area between the port 37 and the land portion 52 becomes smaller, and the opening area of the port 37 tends to become larger.

  The opening area is determined by the balance between the spring force of the spring 53 and the spring 62 and the thrust generated by the pressure in the pressure chamber B. The larger the moving speed of the piston rod 3 with respect to the cylinder 1, the greater the pressure in the pressure chamber B. Since the opening area of the port 36 tends to be small because it becomes high, a large damping force is generated. On the other hand, when the moving speed of the piston rod 3 with respect to the cylinder 1 is low, the pressure in the pressure chamber B does not increase so much. Since the spool 50 does not move much more than the neutral position, that is, the position balanced by the spring force of the spring 53 and the spring 62, the opening area of the port 36 and the port 37 is not reduced, and a low damping force is generated. Become.

  Here, when the winding of the solenoid S is excited, a thrust opposite to the thrust given by the pressure in the pressure chamber B can be given to the spool 50, and the opposing thrust is controlled by the magnitude of the exciting current. As a result, the opening area of the port 36 and the port 37 can be controlled, and thereby the generated damping force can be adjusted.

  Normally, the damping force control is performed by exciting the windings of the solenoid S. However, even if the solenoid S becomes unable to function, the piston rod speed is as described above. Therefore, the damping force is variable, and the vehicle travel is not hindered.

  The hydraulic oil that has passed through the damping force adjusting mechanism has a high pressure in the one chamber R1, so that the plate valve 45 that closes the communication passage 121 of the lower flow path 12 cannot be bent, and the plate valve on the opposite side. 46 is bent and flows into the space A, and further, the inside of the annular leaf valve 24 is bent into the other chamber R2. However, a pressure loss occurs when the annular leaf valve 24 passes, and the damping force is also applied here. In this shock absorber, a damping force is also generated by the annular leaf valve 24 arranged in series with the damping force adjusting mechanism.

  The damping force may be generated only by the damping force adjusting mechanism without providing the annular leaf valve 24. However, in the situation where the solenoid S cannot function by providing the annular leaf valve 24, the piston rod 3 In addition to eliminating the deficiency of damping force at the initial stage of movement, the damping force adjustment mechanism can generate a minimum damping force even when the damping force adjustment mechanism cannot obtain a sufficient damping force. It can be carried out.

  Incidentally, when the pressure on the other chamber R2 side is higher than the pressure on the one chamber R1 side, that is, when the shock absorber contracts, the hydraulic oil first passes through the annular leaf valve 24, and the damping force is reversed. Although it reaches the adjusting mechanism and flows into the one chamber R1, the shock absorber expands because it always passes through the upper flow path 11 to the hollow portion 33 and passes through the lower flow path 12 to the one chamber R1. Similarly to the case, the generated damping force can be controlled by the damping force adjusting mechanism.

  Although the operation of the shock absorber is as described above, in the present embodiment, the solenoid S is not provided in the piston part P, but is provided in the other end of the piston rod 3, so that the piston part The strength of P is not reduced unnecessarily, and the assembly of the piston rod and the piston is the same as that of a normal hydraulic shock absorber, so that the accuracy of the coaxiality is not insufficient and is complicated. Sufficient accuracy can be ensured without performing assembly work, and the number of man-hours for assembly of the shock absorber is reduced.

  In addition, since the spool is used, the assembling work becomes very simple as compared to the poppet valve that needs to be assembled while ensuring the accuracy of the coaxiality, and there is no problem of ensuring the coaxiality.

  Next, a shock absorber according to another embodiment will be described. The shock absorbers in other embodiments are basically the same in configuration as the shock absorbers in the above-described one embodiment, but the configuration of the periphery of the hollow portion 72 and the damping force adjusting mechanism in the flow channel 71 is different. .

  Hereinafter, different parts will be described, and the same parts as those of the shock absorber in one embodiment will be denoted by the same reference numerals as those in the first embodiment, and detailed description thereof will be omitted.

  First, the flow path 71 includes a hollow portion 72 provided on the outer peripheral side of the reduced diameter portion 80 provided at one end which is the lower end of the piston rod 3 in FIG. 3, the one chamber R1 and the other chamber. The upper flow path 11 that allows only the flow of hydraulic oil from the high pressure side to the hollow portion 72 of R2, and the downstream that allows only the flow of hydraulic oil from the hollow portion 72 to the low pressure side of the one chamber R1 and the other chamber R2. The upper flow path 11 and the lower flow path 12 described above are configured in the same manner as in the embodiment, and are provided in the annular piston body 70.

  Further, on the inner peripheral side of the piston main body 70, a diameter-expanded portion 73 is formed from the upper end to the vicinity of the lower end in FIG. 3, and an annular groove 711 and an annular groove 712 are formed in the enlarged diameter portion 73. The annular groove 711 is formed wider than the annular groove 712 and communicates with the connection path 112 of the upper flow path 11, and the annular groove 712 is connected to the connection path 122 of the lower flow path. It is communicated to.

  Further, the piston rod 3 is formed hollow in the whole axial direction, that is, in a cylindrical shape, and a reduced diameter portion 80 formed at one end thereof is inserted into the piston main body 70. A hollow portion 72 is formed by a cylindrical gap formed by the outer periphery and the enlarged diameter portion 73 of the piston body 70.

  Further, one end side of the piston rod 3 is sealed with a stopper 81, and a control rod 82 is communicated with the shaft core portion. A pin 83 is coupled to the lower end of the control rod 82 in FIG. 3 and is connected to the movable iron core 60, and this pin 83 is formed above the reduced diameter portion 80 of the piston rod 3 in FIG. 3. The pair of holes 84 project outside the reduced diameter portion 80, that is, into the hollow portion 72.

  Subsequently, the damping force adjusting mechanism includes a spool 90 and a solenoid S, as in the damping force adjusting mechanism in the embodiment.

  In more detail below, the spool 90 is formed in a substantially cylindrical shape and is slidably inserted into the hollow portion 72. Further, the spool 90 has land portions 91 and 92 formed at both the upper and lower ends in FIG. 3 which are both ends. The land portion 91 is opposed to the annular groove 711, and the land portion 92 is opposed to the annular groove 712. is there.

  Further, the pressure chamber C is defined in the hollow portion 72 by the lower end in FIG. 3 of the spool 90, and the pressure chamber C is connected to the upper flow path 11 via the annular groove 711. The pressure in the upper flow path 11 guided to the pressure can be applied to the spool 90 with the lower end surface of the spool 90 as a pressure receiving surface, so that a thrust can be applied to the spool 90 upward in FIG.

  Further, the upper end of the spool 90 is brought into contact with the pin 83 connected to the control rod 82, and when the winding in the solenoid S is excited, the spool 90 is connected to the spool 90 via the control rod 82 and the pin 83 in FIG. Thrust can be given in the direction of pushing down.

  When the pin 83 moves up and down under the restriction of the hole 84 and the spool 90 moves up and down in FIG. 3, the land portion 91 and the land portion 92 do not completely close the annular grooves 711 and 712, respectively. Further, the vertical width of the land portion 91 is smaller than the vertical width of the annular groove 711 so as not to cut off the communication with the pressure chamber C.

  By the movement of the spool 90 in the vertical direction in the damping force adjusting mechanism configured as described above, the outlet opening area d of the upper flow path 11 formed by the land portion 91 and the annular groove 711 and the land portion 92 and the annular groove 712 are formed. The inlet opening area e of the lower flow path 12 can be controlled to change.

  In this other embodiment, since the spring for biasing the spool 90 upward in FIG. 3 is not provided in the pressure chamber C, the spool 90 by the pressure on the upper flow path 11 side is pushed upward in FIG. The outlet opening area d of the upper flow path 11 and the inlet opening area e of the lower flow path 12 formed by the land 92 and the annular groove 712 are balanced by the thrust, the thrust by the solenoid S, and the spring 62 in the solenoid S. However, a spring may be provided in the pressure chamber C.

  Therefore, even in the shock absorber configured as described above, the position of the spool 90 can be controlled by the magnitude of the current that excites the winding of the solenoid S, similarly to the shock absorber in the above-described embodiment. In addition, the damping force can be adjusted by changing the outlet opening area d of the upper flow path 11 and the inlet opening area e of the lower flow path 12.

  And also in this Embodiment, since the solenoid S is not provided in the piston part P, but is provided in the other end of the piston rod 3, it does not reduce the strength of the piston part P unnecessarily. Furthermore, the piston rod and piston are assembled in the same way as a normal hydraulic shock absorber, so the accuracy of the coaxiality will not be insufficient, and sufficient accuracy will be ensured without complicated installation work. This is possible and reduces the man-hours for assembling the shock absorber.

  In addition, since the spool is used, the assembling work becomes very simple as compared to the poppet valve that needs to be assembled while ensuring the accuracy of the coaxiality, and there is no problem of ensuring the coaxiality.

  Furthermore, since the hollow portion 72 is formed on the outer peripheral side of the reduced diameter portion 80 of the piston rod 3, it is possible to increase the flow path area rather than providing a hollow portion inside the piston rod 3, In addition to the advantage that the damping force variable width is increased, it is not necessary to provide a port on the piston rod 3, so that the number of processing steps is reduced and the cost is also reduced.

  In each of the embodiments, the control rod and the spool may be combined to be integrated, but it is desirable that they are separated from each other in terms of easy assembly.

  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 longitudinal cross-sectional view of the shock absorber in one embodiment of the present invention. It is a partial expanded longitudinal cross-sectional view of the shock absorber in one embodiment of the present invention. It is a partially expanded longitudinal cross-sectional view of the buffer in other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston 3 Piston rod 10,71 Flow path 11 Upper flow path 111,121 Communication path 112,122 Connection path 12 Lower flow path 21,70 Piston main body 211,212,711,712 Annular groove 22 Valve disk 221 Annular main body 222 Tube Portion 223 Fixing member 224 Valve seat 23, 35, 36, 37 Port 24 Annular leaf valve 25 Valve stopper 26 Notch 31, 80 Reduced diameter portion 32 Piston nut 33, 72 Hollow portion 38, 81 Plug 42, 43 Pipe 44 Ball 45, 46 Plate valve 47, 48, 84 Hole 50, 90 Spool 51, 52, 91, 92 Land part 53, 62 Spring 54, 82 Control rod 60 Movable iron core 61 Case 63 Stator 65 Spacer 66 Laminated spacer 73 Expanded part 83 Pin A Room B, C Pressure chamber F Free piston G Air chamber The piston unit R1 the one chamber R2 the other chamber S solenoid

Claims (4)

A cylinder, a piston rod having a piston portion slidably inserted into the cylinder at one end, one chamber and the other chamber separated by the piston portion in the cylinder, and one chamber provided in the piston portion; In the shock absorber including a flow path communicating with the other chamber and a damping force adjusting mechanism provided in the middle of the flow path, the flow path includes a hollow portion formed in the piston portion, one chamber, and the other chamber. And an upper flow path that allows only the flow of liquid from the high pressure side to the hollow portion, and a lower flow path that allows only the flow of liquid from the hollow portion to the low pressure side of the one chamber and the other chamber, and a damping force The adjustment mechanism includes a spool that is slidably inserted into the hollow portion, and that is provided with thrust by a solenoid provided at the other end of the piston rod and that is provided with thrust in a direction opposite to the thrust of the solenoid by the pressure of the upper flow path. The spool The land portions are formed on both end sides, with one land portion facing the outlet opening of the upper flow path and the other land portion facing the inlet opening of the lower flow path, and changing the thrust of the solenoid, A shock absorber characterized by adjusting a damping force by changing an outlet opening area of an upper flow path and an inlet opening area of a lower flow path. 2. The pressure chamber in which the pressure of the upper flow path is guided by the spool in the hollow portion, and a spring for urging the spool in a direction opposite to the thrust of the solenoid is provided in the pressure chamber. The shock absorber described. A hole is provided in the axial center portion of the piston, and the piston rod is connected to the piston by inserting the tip into the hole, and the hollow portion is formed by the enlarged diameter portion formed in the middle portion of the hole and the outer periphery of the piston rod. The shock absorber according to claim 1 or 2. The upper flow path is provided with a communication path that connects the one chamber and the other chamber, a connection path that connects the communication path and the hollow portion, and a high-pressure priority shuttle valve is provided in the communication path. The shock absorber according to any one of 1 to 3.

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