JP5759362B2 - Hydraulic shock absorber - Google Patents

Description

  The present invention relates to a hydraulic shock absorber.

  As shown in FIG. 8, a conventional hydraulic shock absorber described in Patent Document 1 or the like has a piston rod 2 attached to the oil chamber of a cylinder 1 attached to one of the vehicle body side and the axle side, and to the other of the vehicle body side and the axle side. The piston 3 provided at the tip of the piston rod 2 divides the oil chamber of the cylinder 1 into a piston-side oil chamber 4A and a rod-side oil chamber 4B, and the piston 3 is provided with a damping force generator 5. . Further, an oil reservoir chamber 6 that compensates for the volume of the piston rod 2 that moves forward and backward in the oil chambers 4A and 4B of the cylinder 1 (including the volume corresponding to the temperature expansion of the oil) communicates with the piston-side oil chamber 4A of the cylinder 1, A valve housing 7 provided with a damping force generator 8 is interposed between the piston-side oil chamber 4 </ b> A and the oil reservoir chamber 6. The oil reservoir 6 is pressurized by the air chamber 6A (a bladder, a free piston, etc. may be interposed between the oil reservoir 6 and the air chamber 6A).

  At this time, the damping force generator 5 includes a compression side damping valve 5A that opens and closes the compression side channel 3A provided in the piston 3, and an extension side damping valve 5B that opens and closes the extension side channel 3B provided in the piston 3. . The damping force generator 8 includes a pressure side damping valve 8A that opens and closes a pressure side channel 7A provided in the valve housing 7, and an extension side damping valve 8B that opens and closes an extension side channel 7B provided in the valve housing 7.

  In the pressure side stroke, the oil in the piston side oil chamber 4A is boosted and flows out from the pressure side damping valve 8A of the pressure side channel 7A to the oil reservoir chamber 6 and from the pressure side damping valve 5A of the pressure side channel 3A to the rod side oil chamber 4B. The pressure side damping force is generated based on the flow path resistance of the pressure side damping valve 8A and the pressure side damping valve 5A. At this time, the oil corresponding to the entry volume of the piston rod 2 is discharged to the oil reservoir 6 through the compression side damping valve 8A. In the extension stroke, the oil in the rod-side oil chamber 4B is pressurized and flows out from the extension-side damping valve 5B of the extension-side passage 3B to the piston-side oil chamber 4A, and the extension side based on the passage resistance of the extension-side damping valve 5B. A damping force is generated, and oil corresponding to the withdrawal volume of the piston rod 2 is supplied from the oil reservoir chamber 6 to the piston-side oil chamber 4A through the extension-side damping valve 8B of the extension-side channel 7B.

JP2007-177877

  In the conventional hydraulic shock absorber, as shown in FIG. 8, in the pressure side stroke, the pressure-rised oil in the piston side oil chamber 4A (COMP chamber) is divided into two oil reservoir chambers 6 rows and rod side oil chamber 4B (TEN chamber) rows. Since the flow is divided into the flow paths 7A and 3A, the pressure in the rod-side oil chamber 4B varies from positive pressure to negative pressure depending on the balance of the pressure-side damping valves 8A and 5A of the flow paths 7A and 3A. That is, the pressure in the rod side oil chamber 4B varies from positive pressure to negative pressure due to the balance between the flow path resistance of the pressure side damping valve 8A and the air pressure in the air chamber 6A and the flow path resistance of the pressure side damping valve 5A. If the flow path resistance of the damping valve 5A is excessive, a vacuum is generated in the rod-side oil chamber 4B, and the decompression force is reduced during reversal of the extension side. Therefore, in order to generate a uniform and stable damping force in such a hydraulic shock absorber, it is necessary to balance the pressure in the three chambers of the piston side oil chamber 4A, the rod side oil chamber 4B, and the oil reservoir chamber 6. .

  In the extension stroke, the pressure-up oil in the rod-side oil chamber 4B only flows out from one flow path 3B to the piston-side oil chamber 4A, and the pressure in the piston-side oil chamber 4A is only the air pressure in the air chamber 6A. There seems to be no fluctuation depending on.

  An object of the present invention is to generate a uniform and stable damping force in a hydraulic shock absorber without having to balance the pressures of the three chambers of the piston side oil chamber, the rod side oil chamber, and the oil reservoir chamber. That is, in the hydraulic shock absorber, the pressure in the piston side oil chamber flows out to the rod side oil chamber and the oil reservoir chamber so that the pressure in the rod side oil chamber does not vary depending on the setting of the flow resistance of the pressure side damping valve. This is to avoid the reduction of the damping force at the time of reversing the extension side.

  According to the first aspect of the present invention, a piston rod attached to the other of the vehicle body side and the axle side is inserted into an oil chamber of a cylinder attached to one of the vehicle body side and the axle side. The oil chamber is divided into a piston-side oil chamber and a rod-side oil chamber, and an oil reservoir chamber that compensates for the volume of the piston rod that moves forward and backward to the cylinder oil chamber is provided on the piston rod in the hydraulic shock absorber that communicates with the cylinder oil chamber. The piston is provided with a damping force generating device, and the damping force generating device includes a compression side damping force generation unit provided in a pressure side flow path for flowing the oil in the piston side oil chamber toward the rod side oil chamber in the compression side stroke; Check valve device between the cylinder oil chamber and the oil reservoir chamber. The check valve device consists of an extension side damping force generator provided in the extension side flow passage that flows the rod side oil chamber toward the piston side oil chamber. The check valve device is equipped with a pressure A pressure check valve that prevents the flow of oil from the piston-side oil chamber to the oil reservoir in the stroke, and allows the oil to flow from the oil reservoir to the piston-side oil chamber in the extension stroke, and the rod side in the extension stroke An extension side check valve is provided that prevents the flow of oil from the oil chamber to the oil reservoir chamber and allows the oil flow from the rod side oil chamber to the oil reservoir chamber in the pressure side stroke.

  In the invention according to claim 2, in the invention according to claim 1, the partition member provided in the cylinder is further provided with a communication flow path for connecting the oil reservoir chamber to both the piston-side oil chamber and the rod-side oil chamber, A pressure side check valve is provided at the connection port with the piston side oil chamber of the communication channel, and an expansion side check valve is provided at the communication port with the rod side oil chamber of the communication channel.

  According to a third aspect of the present invention, in the second aspect of the invention, the partition member is provided between the piston-side oil chamber and the oil reservoir chamber of the cylinder, and the rod-side oil chamber is communicated with the communication channel of the partition member. An outer flow path is provided in the cylinder.

  The invention according to claim 4 is the invention according to claim 2 or 3, wherein the pressure side check valve and the extension side check valve are integrally coupled, the pressure side check valve faces the piston side oil chamber, and the extension side check valve Is designed to face the oil chamber on the rod side.

  The invention according to claim 5 is the invention according to claim 4, further comprising a check valve spring for urging the extension side check valve in the valve opening direction.

  The invention according to claim 6 is the invention according to claim 4 or 5, wherein the pressure receiving area where the pressure side check valve faces the piston side oil chamber is set larger than the pressure receiving area where the extension side check valve faces the rod side oil chamber. It has been made to become.

(Claim 1)
(a) In the pressure side stroke, the pressure side check valve blocks the flow of oil from the piston side oil chamber to the oil reservoir chamber, and the extension side check valve allows the oil flow from the rod side oil chamber to the oil reservoir chamber. As a result, all of the pressurized oil in the piston-side oil chamber generates a compression-side damping force in the process of flowing into the rod-side oil chamber through the compression-side damping force generator of the piston damping force generator. At this time, the oil corresponding to the volume of the piston rod that has entered the oil chamber of the cylinder is discharged from the rod side oil chamber through the extension side check valve to the oil reservoir chamber.

  Accordingly, all of the oil in the piston-side oil chamber that has been boosted in the pressure-side stroke generates a compression-side damping force through only one pressure-side flow path and the compression-side damping force generation unit of the piston. As a result, a uniform and stable damping force can be generated without having to balance the pressure in the three chambers of the piston side oil chamber, the rod side oil chamber, and the oil reservoir chamber.

  And in this pressure side stroke, the pressure of the rod side oil chamber (because the flow path resistance of the cylinder outer channel to the extension side check valve is small) is almost dependent only on the pressure of the air chamber pressurizing the oil reservoir, It does not vary depending on the flow path resistance setting of the compression side damping force generator. Therefore, it is possible to avoid the reduction of the damping force when the extension side is reversed.

  (b) In the extension side stroke, the extension side check valve blocks the flow of oil from the rod side oil chamber to the oil reservoir, and the pressure side check valve allows the oil flow from the oil reservoir to the piston side oil chamber. . As a result, all of the pressurized oil in the rod side oil chamber generates an extension side damping force in the process of flowing into the piston side oil chamber through the extension side damping force generating portion of the piston damping force generator. At this time, the oil corresponding to the retraction volume of the piston rod that retreats from the oil chamber of the cylinder is supplied from the oil reservoir chamber to the piston side oil chamber through the pressure side check valve.

  Accordingly, all of the oil in the rod side oil chamber whose pressure is increased in the extension side stroke generates the extension side damping force through only one extension side flow path and the extension side damping force generating portion of the piston. As a result, a uniform and stable damping force can be generated without having to balance the pressure in the three chambers of the piston side oil chamber, the rod side oil chamber, and the oil reservoir chamber.

  In this extension side stroke, the pressure in the piston side oil chamber (because the flow path resistance of the pressure side check valve is small) almost depends only on the pressure of the air chamber that pressurizes the oil reservoir chamber, and the extension side damping force generating section It does not fluctuate depending on the channel resistance setting. Therefore, it is possible to avoid the damping force from being reduced when the pressure side is reversed.

(Claim 2)
(c) The partition member provided in the cylinder is provided with a communication channel that connects the oil reservoir chamber to both the piston-side oil chamber and the rod-side oil chamber, and the communication side is connected to the piston-side oil chamber at the pressure side. A check valve was provided, and an extension side check valve was provided at the connection port with the rod side oil chamber of the communication channel. Therefore, the configuration of the check valve device provided between the oil chamber and the oil reservoir chamber of the cylinder can be simplified.

(Claim 3)
(d) The partition member is provided between the piston-side oil chamber and the oil reservoir chamber of the cylinder, and the cylinder is provided with an outer channel that communicates the rod-side oil chamber with the communication channel of the partition member. Therefore, the structure of the check valve device provided between the oil chamber and the oil reservoir chamber of the cylinder can be further simplified.

(Claim 4)
(e) The pressure side check valve and the extension side check valve are integrally connected, the pressure side check valve faces the piston side oil chamber, and the extension side check valve faces the rod side oil chamber. Therefore, the structure of the check valve device provided between the oil chamber and the oil reservoir chamber of the cylinder can be further simplified.

(Claim 5)
(f) A check valve spring for urging the extension side check valve in the valve opening direction is provided. Therefore, the expansion check valve is reliably opened during the compression stroke of the expansion / contraction stroke of the hydraulic shock absorber, and the compression check valve integrated with the expansion check valve is closed. Can be improved.

  In addition, when the pressure of the hydraulic shock absorber is stopped, even if the pressure in the piston-side oil chamber is equal to the pressure in the rod-side oil chamber, the pressure-side check valve is securely closed and the expansion-side check valve is reliably opened. Therefore, the response and stability of the damping force can be improved.

(Claim 6)
(g) The pressure receiving area where the pressure side check valve faces the piston side oil chamber is set larger than the pressure receiving area where the extension side check valve faces the rod side oil chamber. Therefore, the expansion check valve is reliably opened during the compression stroke of the expansion / contraction stroke of the hydraulic shock absorber, and the compression check valve integrated with the expansion check valve is closed. Can be improved.

  In addition, when the pressure of the hydraulic shock absorber is stopped, even if the pressure in the piston-side oil chamber is equal to the pressure in the rod-side oil chamber, the pressure-side check valve is securely closed and the expansion-side check valve is reliably opened. Therefore, the response and stability of the damping force can be improved.

FIG. 1 is an overall cross-sectional view showing a hydraulic shock absorber. FIG. 2 is an enlarged cross-sectional view of the main part of FIG. FIG. 3 is a cross-sectional view showing the check valve device. FIG. 4 is a cross-sectional view showing the flow of oil in the compression side stroke in the hydraulic shock absorber. FIG. 5 is an enlarged cross-sectional view of the main part of FIG. FIG. 6 is a cross-sectional view showing the flow of oil in the extension side stroke in the hydraulic shock absorber. FIG. 7 is an enlarged cross-sectional view of the main part of FIG. FIG. 8 is a schematic view showing a conventional hydraulic shock absorber.

  As shown in FIGS. 1 and 2, the hydraulic shock absorber 10 has a piston rod 12 inserted into a cylinder 11 and a suspension spring (not shown) interposed between the cylinder 11 and the piston rod 12. The cylinder 11 includes a vehicle body side mounting member 14, and the piston rod 12 includes an axle side mounting member 15. The cylinder 11 may be provided with an axle side attachment member, and the piston rod 12 may be provided with a vehicle body side attachment member.

  The cylinder 11 is provided with a rod guide 20 through which the piston rod 12 penetrates in a fluid-tight manner. The rod guide 20 allows the piston rod 12 to slide in a liquid-tight manner on an inner diameter portion including an oil seal 21 and a bush 22. The cylinder 11 includes a washer 23 and a rebound rubber 24 inside the rod guide 20. Further, a bump rubber 25 is provided on the outer peripheral portion of the piston rod 12 near the axle side mounting member 15, and a bump stopper cap 26 is provided on the opening end of the cylinder 11 where the rod guide 20 is fitted.

  In the hydraulic shock absorber 10, the cylinder 11 is a double pipe composed of an outer cylinder 11A and an inner cylinder 11B, a vehicle body side mounting member 14 is provided on the upper end outer surface of the outer cylinder 11A, and a rod guide 20 is provided on the inner periphery of the lower end side of the outer cylinder 11A. Are attached to the small outer diameter portion of the rod guide 20 by fitting the inner periphery of the lower end of the inner cylinder 11B. Further, a large outer diameter portion of a partition wall member 31 to be described later is attached to the inner periphery of the intermediate portion of the cylinder 11, and the upper end inner periphery of the inner cylinder 11 </ b> B is fitted to the small outer diameter portion of the partition wall member 31. The piston 27 inserted into the tip of the piston rod 12 is fixed with a nut 28, and the piston 27 inserted in the inner periphery of the inner cylinder 11B is slidable so that the oil chamber 29 of the cylinder 11 is moved to the piston side oil chamber. It divides into 29A and the rod side oil chamber 29B.

  The hydraulic shock absorber 10 defines an oil reservoir chamber 30 that compensates for the volume of the piston rod 12 that moves forward and backward in the oil chamber 29 of the cylinder 11, and the oil reservoir chamber 30 is connected to the cylinder 11 via a check valve device 50 described later. A partition wall member 31 communicating with the oil chamber 29 is provided. The partition wall member 31 is sandwiched between a fixing ring 33 fixedly held by a protrusion 32 provided on the inner periphery of the upper end of the outer cylinder 11 </ b> A of the cylinder 11 and the upper end surface of the inner cylinder 11 </ b> B of the cylinder 11. The The cylinder 11 defines an air chamber 35 above the oil reservoir chamber 30 via a free piston 34, and pressurizes the oil reservoir chamber 30 with the pressure of the air chamber 35.

  The damping force generator 40 includes a valve stopper 41 at the tip of the piston rod 12, a compression side damping force generation unit 42 including a plate valve, a piston 27, an extension side damping force generation unit 43 including a plate valve, and a valve stopper 44 in this order. It is configured by inserting and fixing them with a nut 28. At this time, the piston 27 is provided with a pressure side channel 42A and an extension side channel 43A. The pressure-side damping force generating unit 42 is provided in the pressure-side flow path 42A that flows the oil in the piston-side oil chamber 29A toward the rod-side oil chamber 29B in the pressure-side stroke, and generates a pressure-side damping force by the flow path resistance. The extension side damping force generation unit 43 is provided in the extension side flow path 43A that flows the oil in the rod side oil chamber 29B toward the piston side oil chamber 29A in the extension side stroke, and the extension side damping force is generated by the flow path resistance. Occur.

  The damping force generator 40 is provided with a damping force adjusting device 45. The damping force adjusting device 45 is provided in the hollow portion of the piston rod 12 with a bypass channel 46 that communicates the piston-side oil chamber 29 </ b> A and the rod-side oil chamber 29 </ b> B of the cylinder 11. Then, a bypass valve 46 that faces the piston-side oil chamber 29A is moved by a cam 48 that is rotated by an adjuster 47 provided on the axle-side mounting member 15 to move the needle valve 49 that is inserted through the hollow portion of the piston rod 12. By adjusting the opening area of the opening 46A, the expansion-side damping force and the compression-side damping force are adjusted in both strokes.

  As shown in FIGS. 1 to 3, the check valve device 50 includes a pressure side check valve 51 and an extension side check valve 52. The pressure-side check valve 51 blocks the flow of oil from the piston-side oil chamber 29A to the oil reservoir 30 in the pressure-side stroke, and allows the oil to flow from the oil reservoir 30 to the piston-side oil chamber 29A in the extension-side stroke. . The extension side check valve 52 prevents the flow of oil from the rod side oil chamber 29B to the oil reservoir chamber 30 in the extension side stroke, and allows the oil flow from the rod side oil chamber 29B to the oil reservoir chamber 30 in the compression side stroke. To do.

  Here, the aforementioned partition member 31 is provided between the piston-side oil chamber 29A and the oil reservoir 30 of the cylinder 11, and the oil reservoir 30 is connected to the partition-side member 31 between the piston-side oil chamber 29A and the rod-side oil chamber 29B. A communication channel 60 is provided to communicate with both sides. At this time, the partition member 31 includes an outer ring 31A that is fitted and held in the outer cylinder 11A and the inner cylinder 11B of the cylinder 11, and an inner ring 31B that is fitted and screwed to the outer ring 31A. A communication port 61 with the piston-side oil chamber 29 </ b> A of the communication channel 60 is provided in the inner ring 31 </ b> B, and a pressure-side check valve 51 is provided in the communication port 61. In addition, a communication port 62 with the rod-side oil chamber 29 </ b> B of the communication channel 60 is provided in the outer ring 31 </ b> A, and an extension check valve 52 is provided in the communication port 62. The communication port 63 of the communication channel 60 with the oil reservoir 30 communicates with an intermediate chamber 64 sandwiched between the compression side check valve 51 and the extension side check valve 52.

  In addition, an outer flow path 70 that connects the rod-side oil chamber 29 </ b> B to the communication flow path 60 (communication port 62) of the partition wall member 31 is provided in the cylinder 11. The outer flow path 70 includes an annular gap between the outer cylinder 11A and the inner cylinder 11B, communicates with the rod-side oil chamber 29B through a communication port 71 provided in the inner cylinder 11B, and communicates with the communication flow path 60 provided in the partition wall member 31. It communicates directly with the mouth 62.

  Further, the check valve device 50 has a valve shaft 53 that is inserted into the center hole 31C of the inner ring 31B of the partition wall member 31 and can slide in the axial direction of the center hole 31C. A disk-like pressure side check valve 51 is fixed to one end face of the valve shaft 53 with a bolt 54, and a disk-like extension side check valve 52 is fixed to the other end face of the valve shaft 53 with a bolt 55. That is, the pressure side check valve 51 and the extension side check valve 52 are integrally coupled via a valve shaft 53, and the pressure side check valve 51 is a communication port communicating with the piston side oil chamber 29A, in this embodiment the piston side oil chamber 29A. Come to 61. The extension side check valve 52 faces the connecting port 62 communicating with the rod side oil chamber 29B, in this embodiment, the rod side oil chamber 29B. The pressure side check valve 51 and the expansion side check valve 52 are movable up and down along the central hole 31C of the inner ring 31B of the partition wall member 31 together with the valve shaft 53. When the pressure side check valve 51 closes the communication port 61, the pressure side check valve 51 and the expansion side check valve 52 are extended. The side check valve 52 opens the communication port 62, and the expansion side check valve 52 closes the communication port 62 when the pressure side check valve 51 opens the communication port 61.

  The check valve device 50 is provided with a check valve spring 56 that biases the extension side check valve 52 in the valve opening direction. The check valve spring 56 is a compression coil spring that is sandwiched between the end face of the inner ring 31 </ b> B and the extension side check valve 52 around the valve shaft 53.

  Further, the check valve device 50 has a pressure receiving area where the pressure side check valve 51 faces the piston side oil chamber 29A (the communication port 61), and a pressure receiving area where the expansion side check valve 52 faces the rod side oil chamber 29B (the communication port 62). It is set large.

Therefore, according to the hydraulic shock absorber 10, the following operational effects can be obtained.
(a) In the pressure side stroke, as shown in FIGS. 4 and 5, the pressure side check valve 51 blocks the flow of oil from the piston side oil chamber 29 </ b> A to the oil reservoir chamber 30, and the extension side check valve 52 serves as the rod side oil chamber. The flow of oil from 29B to the oil reservoir 30 is allowed. As a result, all of the pressurized oil in the piston-side oil chamber 29A generates a compression-side damping force in the process of flowing into the rod-side oil chamber 29B through the compression-side damping force generating unit 42 of the damping force generating device 40 of the piston 27. . At this time, the oil corresponding to the volume of the piston rod 12 that has entered the oil chamber 29 of the cylinder 11 is discharged from the rod-side oil chamber 29 </ b> B to the oil reservoir chamber 30 through the extension-side check valve 52.

  Accordingly, all of the oil in the piston-side oil chamber 29 </ b> A boosted in the pressure-side stroke generates a compression-side damping force through only one pressure-side flow path 42 </ b> A of the piston 27 and the compression-side damping force generator 42. Accordingly, it is not necessary to balance the pressure of the three chambers of the piston side oil chamber 29A, the rod side oil chamber 29B, and the oil reservoir chamber 30, and a uniform and stable damping force is generated.

  In this pressure side stroke, the pressure in the rod side oil chamber 29B (because the flow path resistance of the outer side flow path 70 to the extension side check valve 52 of the cylinder 11 is small) is the pressure of the air chamber 35 that pressurizes the oil reservoir 30. And does not vary depending on the setting of the flow path resistance of the compression side damping force generation unit 42. Therefore, it is possible to avoid the reduction of the damping force when the extension side is reversed.

  (b) In the extension side stroke, as shown in FIGS. 6 and 7, the extension side check valve 52 blocks the flow of oil from the rod side oil chamber 29 </ b> B to the oil reservoir chamber 30, and the pressure side check valve 51 serves as the oil reservoir chamber. The oil flow from 30 to the piston side oil chamber 29A is allowed. As a result, all of the pressure-rised oil in the rod-side oil chamber 29B passes through the extension-side damping force generator 43 of the damping force generator 40 of the piston 27 and flows into the piston-side oil chamber 29A. Occur. At this time, the oil corresponding to the retraction volume of the piston rod 12 retreating from the oil chamber 29 of the cylinder 11 is replenished from the oil reservoir 30 through the pressure side check valve 51 to the piston side oil chamber 29A.

  Accordingly, all of the oil in the rod side oil chamber 29 </ b> B boosted in the extension side stroke generates the extension side damping force through only one extension side flow path 43 </ b> A of the piston 27 and the extension side damping force generation unit 43. Accordingly, it is not necessary to balance the pressure of the three chambers of the piston side oil chamber 29A, the rod side oil chamber 29B, and the oil reservoir chamber 30, and a uniform and stable damping force is generated.

  In this pressure-side stroke, the pressure in the piston-side oil chamber 29A (because the flow path resistance of the pressure-side check valve 51 is small) substantially depends only on the pressure in the air chamber 35 that pressurizes the oil reservoir chamber 30, and the expansion-side damping. It does not vary depending on the setting of the channel resistance of the force generator 43. Therefore, it is possible to avoid the damping force from being reduced when the pressure side is reversed.

  (c) The partition member 31 provided in the cylinder 11 is provided with a communication channel 60 that connects the oil reservoir 30 to both the piston-side oil chamber 29A and the rod-side oil chamber 29B. The pressure side check valve 51 is provided in the communication port 61 with the chamber 29A, and the expansion side check valve 52 is provided in the communication port 62 with the rod side oil chamber 29B of the communication flow path 60. Therefore, the configuration of the check valve device 50 provided between the oil chamber 29 and the oil reservoir 30 of the cylinder 11 can be simplified.

  (d) The partition wall member 31 is provided between the piston-side oil chamber 29A and the oil reservoir chamber 30 of the cylinder 11, and the outer flow path 70 that connects the rod-side oil chamber 29B to the communication flow path 60 of the partition wall member 31 is provided in the cylinder 11. Provided. Therefore, the configuration of the check valve device 50 provided between the oil chamber 29 and the oil reservoir 30 of the cylinder 11 can be further simplified.

  (e) The pressure side check valve 51 and the extension side check valve 52 are integrally coupled, the pressure side check valve 51 faces the piston side oil chamber 29A, and the extension side check valve 52 faces the rod side oil chamber 29B. Therefore, the configuration of the check valve device 50 provided between the oil chamber 29 and the oil reservoir 30 of the cylinder 11 can be further simplified.

  (f) A check valve spring 56 for urging the extension side check valve 52 in the valve opening direction is provided. Accordingly, the expansion side check valve 52 is surely opened in the pressure side stroke of the expansion / contraction stroke of the hydraulic shock absorber 10, and the pressure side check valve 51 integrated with the expansion side check valve 52 is closed, and the response of the damping force And stability can be improved.

  Further, even if the pressure of the piston side oil chamber 29A and the pressure of the rod side oil chamber 29B are equal when the hydraulic shock absorber 10 is in the expansion / contraction stop state, the pressure side check valve 51 is reliably closed and the extension side check valve 52 is closed. Can be surely opened, and the response and stability of the damping force can be improved.

  (g) The pressure receiving area where the pressure side check valve 51 faces the piston side oil chamber 29A is set larger than the pressure receiving area where the extension side check valve 52 faces the rod side oil chamber 29B. Accordingly, the expansion side check valve 52 is surely opened in the pressure side stroke of the expansion / contraction stroke of the hydraulic shock absorber 10, and the pressure side check valve 51 integrated with the expansion side check valve 52 is closed, and the response of the damping force And stability can be improved.

  Further, even if the pressure of the piston side oil chamber 29A and the pressure of the rod side oil chamber 29B are equal when the hydraulic shock absorber 10 is in the expansion / contraction stop state, the pressure side check valve 51 is reliably closed and the extension side check valve 52 is closed. Can be surely opened, and the response and stability of the damping force can be improved.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

  The present invention inserts a piston rod attached to the other of the vehicle body side and the axle side into a cylinder oil chamber attached to one of the vehicle body side and the axle side, and the piston provided on the piston rod causes the cylinder oil chamber to A hydraulic shock absorber that is divided into a side oil chamber and a rod side oil chamber, and that compensates the volume of the piston rod that advances and retreats into the cylinder oil chamber, communicates with the cylinder oil chamber. A force generating device, and the damping force generating device includes a pressure side damping force generator provided in a pressure side flow path for flowing the oil in the piston side oil chamber toward the rod side oil chamber in the pressure side stroke, and a rod in the extension side stroke. It consists of an extension side damping force generator provided in the extension side flow path that flows the oil in the side oil chamber toward the piston side oil chamber, and a check valve device is provided between the oil chamber of the cylinder and the oil reservoir chamber. The valve device is A pressure check valve that prevents the flow of oil from the cylinder side oil chamber to the oil reservoir chamber and allows the oil flow from the oil reservoir chamber to the piston side oil chamber in the extension stroke, and the rod side oil chamber in the extension stroke. It consists of an extension check valve that prevents the flow of oil from the oil reservoir to the oil reservoir and allows the flow of oil from the rod side oil chamber to the oil reservoir in the pressure side stroke. Thereby, in the hydraulic shock absorber, a uniform and stable damping force can be generated without having to balance the pressures of the three chambers of the piston side oil chamber, the rod side oil chamber, and the oil reservoir chamber.

DESCRIPTION OF SYMBOLS 10 Hydraulic buffer 11 Cylinder 12 Piston rod 27 Piston 29 Oil chamber 29A Piston side oil chamber 29B Rod side oil chamber 30 Oil reservoir chamber 31 Partition member 40 Damping force generator 42 Pressure side damping force generation part 42A Pressure side flow path 43 Stretch side damping Force generating portion 43A Stretch side flow path 50 Check valve device 51 Pressure side check valve 52 Stretch side check valve 56 Check valve spring 60 Communication flow path 61 Communication port 62 Communication port 70 Outer flow path

Claims (6)

A piston rod attached to the other of the vehicle body side and the axle side is inserted into an oil chamber of a cylinder attached to one of the vehicle body side and the axle side, and the cylinder oil chamber is connected to the piston side oil chamber by a piston provided on the piston rod. Partition into the oil chamber on the rod side,
In a hydraulic shock absorber that communicates an oil reservoir chamber that compensates for the volume of the piston rod that advances and retreats into and from the cylinder oil chamber,
The piston provided on the piston rod is equipped with a damping force generator,
The damping force generator is
A pressure-side damping force generator provided in a pressure-side flow path for flowing the oil in the piston-side oil chamber toward the rod-side oil chamber in the pressure-side stroke;
The extension side stroke consists of an extension side damping force generating part provided in the extension side flow path for flowing the oil in the rod side oil chamber toward the piston side oil chamber,
A check valve device is provided between the oil chamber and the oil reservoir of the cylinder,
Check valve device
A pressure-side check valve that prevents the flow of oil from the piston-side oil chamber to the oil reservoir in the pressure-side stroke and allows the oil to flow from the oil reservoir to the piston-side oil chamber in the extension stroke;
It consists of an extension side check valve that prevents the flow of oil from the rod side oil chamber to the oil reservoir chamber in the extension side stroke and allows the flow of oil from the rod side oil chamber to the oil reservoir chamber in the pressure side stroke. And hydraulic shock absorber. The partition member provided in the cylinder is provided with a communication channel that connects the oil reservoir chamber to both the piston-side oil chamber and the rod-side oil chamber,
A pressure check valve is provided at the connection port with the piston side oil chamber of the communication flow path,
The hydraulic shock absorber according to claim 1, wherein an extension side check valve is provided at a connection port between the connection flow path and the rod side oil chamber.   3. The hydraulic shock absorber according to claim 2, wherein the partition member is provided between a piston-side oil chamber and an oil reservoir chamber of the cylinder, and an outer flow path that connects the rod-side oil chamber to a communication flow path of the partition member is provided in the cylinder. vessel.   The hydraulic buffer according to claim 2 or 3, wherein the pressure side check valve and the extension side check valve are integrally coupled, the pressure side check valve faces the piston side oil chamber, and the extension side check valve faces the rod side oil chamber. vessel.   The hydraulic shock absorber according to claim 4, further comprising a check valve spring that urges the extension side check valve in a valve opening direction.   The hydraulic shock absorber according to claim 4 or 5, wherein the pressure receiving area where the pressure side check valve faces the piston side oil chamber is set larger than the pressure receiving area where the expansion side check valve faces the rod side oil chamber.

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