JP2017187051A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber which can obtain a proper attenuation force corresponding to a relative position and a moving speed in a stroke direction between an axle-side tube and a vehicle-body side tube.SOLUTION: This shock absorber comprises the following constitution. An axle-side tube is sealed with oil. A sheet pipe is erected at an axial core of the axle-side tube, and has a check valve mechanism. A vehicle-body side tube is inserted with the sheet pipe from a lower end side opening part, connected to the axle-side tube, and relatively moves along an axial direction with respect to the axle-side tube. A hollow rod pipe is erected at an axial core of the vehicle-body side tube, slidably inserted into the sheet pipe in the axial direction, and has a communication hole at its bulkhead part. A suspension spring is interposed between an upper end side closed part of the vehicle-body side tube and an upper end part of the sheet pipe. A check valve mechanism limits a flow of oil which passes the communication hole according to the relative displacement of the axle-side tube and the vehicle-body side tube.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to a shock absorber.

  There is known a front fork for a motorcycle in which an inner tube is slidably inserted into an outer tube, and a seat pipe having a partition wall slidably contacting the inner periphery of the inner tube is erected on the bottom of the outer tube. Yes. This front fork divides an oil chamber in which the piston provided at the tip of the inner tube advances and retreats on the outer periphery of the seat pipe, and also provides an oil reservoir chamber extending from the inner periphery of the seat pipe to the inside of the inner tube. The upper part is a gas chamber. Furthermore, in this front fork, a suspension spring inserted into the inner tube is interposed between the upper end portion of the inner tube and the seat pipe.

  In this type of front fork, for example, a sub seat pipe having an upper end corresponding to a partition portion of the seat pipe is inserted into the seat pipe, and the sub seat pipe is moved according to the movement of the sub seat pipe into the seat pipe. There are some in which a plurality of communication holes, which are sequentially closed on the inner surface, are provided on the side wall of the seat pipe. Further, the front fork has a structure in which a plurality of side holes that are sequentially closed on the inner surface of the seat pipe are provided in the side wall of the sub seat pipe in accordance with the movement of the sub seat pipe into the seat pipe.

  Such a front fork has a damping effect by sequentially closing the plurality of communication holes in the side wall of the seat pipe during the compression process of the inner tube, and the side pipe in the side wall of the sub seat pipe. A damping effect by sequentially closing is obtained, whereby the damping force can be changed according to the stroke position of the inner tube.

Japanese Examined Patent Publication No. 4-72093 JP 2007-32735 A JP 2008-208860 A JP 2004-11702 A JP 2003-232395 A

  However, the front fork having the structure as described above generally moves a small amount of oil in the same flow path at the time of extension side and at the time of compression side, so that the stroke speed of the inner tube is relatively high. The oil flow is delayed, making it difficult to obtain a desired damping force against vibration.

  Therefore, the problem to be solved by the present invention is to provide a shock absorber that can obtain an appropriate damping force according to the relative position and moving speed of the axle side tube and the vehicle body side tube in the stroke direction. is there.

  The shock absorber according to the embodiment includes an axle side tube, a seat pipe, a vehicle body side tube, a rod pipe, and a suspension spring. The axle side tube is provided on the axle side, the upper end side is open, the lower end side is closed, and oil is sealed. The seat pipe is erected on the shaft center of the lower end side closing portion of the axle side tube, and the check valve mechanism provided at the upper end side enlarged diameter portion, the upper end side of which opens and expands, and the partition wall portion And side holes provided in the. The vehicle body side tube is provided on the vehicle body side, the upper end side is closed, the lower end side is opened, a seat pipe is inserted from the lower end side opening portion, and is connected to the axle side tube. Move relatively along. The rod pipe is hollow and is erected on the shaft center of the upper end side closing portion of the vehicle body side tube, and is slidably inserted in the axial direction of the seat pipe from the upper end side opening portion of the seat pipe. A communication hole is provided in the partition wall. The suspension spring is provided inside the vehicle body side tube and is interposed between the upper end side closing portion of the vehicle body side tube and the upper end portion of the seat pipe. Furthermore, the check valve mechanism restricts the flow of oil passing through the communication hole of the rod pipe in accordance with the relative displacement between the axle side tube and the vehicle body side tube.

It is sectional drawing which shows the structure of the buffer which concerns on this embodiment. It is sectional drawing which expands and shows the state just before extending the buffer of FIG. It is sectional drawing which expands and shows the state just before the most compression of the shock absorber of FIG. FIG. 3 is a cross-sectional view showing a state where a first check valve in FIG. 2 is closed. FIG. 5 is a cross-sectional view showing a state where a first check valve of FIG. 4 is opened. FIG. 3 is a cross-sectional view showing a state where a second check valve in FIG. 2 is closed. It is sectional drawing which shows the state by which the 2nd check valve of FIG. 6 was opened. It is a figure which shows the relationship between the relative position and moving speed of the stroke direction of the axle side tube with which the shock absorber of FIG.

  Hereinafter, embodiments will be described with reference to the drawings. As shown in FIGS. 1 to 3, the shock absorber 10 according to the present embodiment is an upright front fork interposed between a vehicle body and a front wheel of a motorcycle. The upper end side of the shock absorber 10 is fixed to a stem shaft inserted through the steering head pipe on the vehicle body side via a bracket. One shock absorber 10 is disposed on each of the left and right front wheels of the motorcycle.

  As shown in FIGS. 1 to 3, the shock absorber 10 mainly includes an axle side tube 15 that is an outer tube, a vehicle body side tube 16 that is an inner tube, a seat pipe 17, a rod pipe 18, a suspension spring 12, and a chamber 19. I have.

  The axle tube 15 is provided on the axle side of the motorcycle, the upper end side (the motorcycle body side) is open, the lower end side (the axle side) is closed, and an oil (damper oil) 8 is provided. Is enclosed. A dust seal 24 and an oil seal 25 are provided at the peripheral portion of the opening on the upper end side of the axle side tube 15 where the vehicle body side tube 16 advances and retreats.

  The seat pipe 17 is erected on the shaft center of the lower end side closing portion 15a of the axle side tube 15 via a bolt 26 and a support member 27, and its upper end side opens and expands, and its upper end side expands. It has the 1st check valve mechanism 50 provided in the part 17d, and the side hole 17e provided in the lower end side of the partition part of the said seat pipe 17. FIG. Further, the seat pipe 17 has a plurality of oil holes 17a and 17b provided on the upper end side of the partition wall.

  The vehicle body side tube 16 is provided on the vehicle body side of the motorcycle, the upper end side is closed, the lower end side is opened, the seat pipe 17 is inserted from the lower end side opening portion 16a, and is connected to the axle side tube 15 to be connected to the axle side. It moves relative to the tube 15 along its axial direction.

  As shown in FIGS. 1 to 3, the rod pipe 18 is hollow, is erected on the axis of the upper end side closing portion 16 b of the vehicle body side tube 16, and extends from the upper end side opening portion 17 f of the seat pipe 17. The seat pipe 17 is slidably inserted in the axial direction, and a plurality of communication holes 18a and 18b are provided as bypass holes in the partition wall. The communication hole 18 a and the communication hole 18 b are provided with an interval in the axial direction of the rod pipe 18.

  Here, the hole diameters of the communication hole 18a and the communication hole 18b may be different from each other, and the axial positions of the communication holes 18a and 18b on the rod pipe 18 and the interval (pitch) between them may be set. You may change suitably. Further, the number of communication holes arranged in the axial direction on the rod pipe 18 may be three or more. As a result, the damping force can be adjusted.

  As shown in FIGS. 2 and 3, the shock absorber 10 of the present embodiment is another set at a position opposed to the communication holes 18 a and 18 b in the radial direction across the axis of the rod pipe 18. Communication holes (4 communication holes in total) are provided. Further, these communication holes 18a and 18b have a diameter that is several times larger than the plurality of oil holes 17a and 17b described above.

  The suspension spring 12 is provided inside the vehicle body side tube 16, and between the upper end portion (upper end side closing portion 16 b) of the vehicle body side tube 16 and the upper end portion (first check valve mechanism 50) of the seat pipe 17. It is an interposition compression coil spring. The shock absorber 10 further includes a rebound spring 29. The rebound spring 29 generates a repulsive force in a direction in which the vehicle body side tube 16 is pushed back into the axle side tube 15 in the vicinity of the maximum extension of the shock absorber 10.

  As shown in FIG. 1, the chamber 19 has a pipe shape larger in diameter than the rod pipe 18 and extends to the rod pipe 18. The chamber 19 is disposed coaxially with the rod pipe 18, and a lower end portion thereof is fixed to an upper end portion of the rod pipe 18 via a nut 28. A plurality of side holes 19 a are formed in the partition wall of the chamber 19. The upper end portion of the chamber 19 and the uppermost end portion of the vehicle body side tube 16 body are closed by a cap 22.

  Moreover, the shock absorber 10 includes first to fifth oil chambers 61, 62, 63, 64, 65 as shown in FIGS. The first oil chamber 61 is disposed between the inner peripheral side of the vehicle body side tube 16 and the outer peripheral side of the rod pipe. More specifically, the first oil chamber 61 is formed by the inner peripheral side of the vehicle body side tube 16, the outer peripheral side of the rod pipe 18, the first check valve mechanism 50, and the upper end side closing portion 16 b of the vehicle body side tube 16. It is an enclosed oil chamber. The second oil chamber 62 is disposed on the inner peripheral side of the seat pipe 17.

  The third oil chamber 63 is disposed between the inner peripheral side of the vehicle body side tube 16 and the outer peripheral side of the seat pipe 17. Specifically, the third oil chamber 63 is surrounded by the inner peripheral side of the vehicle body side tube 16, the outer peripheral side of the seat pipe 17, the first check valve mechanism 50, and a second check valve mechanism 70 described later. It is an oil chamber.

  On the other hand, the fourth oil chamber 64 is disposed between the inner peripheral side of the axle-side tube 15 and the outer peripheral side of the seat pipe. More specifically, the fourth oil chamber 64 includes an inner peripheral side of the axle side tube 15, an outer peripheral side of the seat pipe 17, a second check valve mechanism 70 described later, and a lower end side closing portion 15 a of the axle side tube 15. It is an oil chamber surrounded by Further, the fifth oil chamber 65 is disposed on the inner peripheral side of the chamber 19.

  Here, the first check valve mechanism 50 restricts the flow of oil passing through the communication hole 18a and the communication hole 18b of the rod pipe 18 according to the relative displacement between the axle side tube 15 and the vehicle body side tube 16. To do. When the first check valve mechanism 50 restricts the flow of oil, as shown in FIG. 3, the oil cannot flow into the first oil chamber 61 due to the positional relationship with the communication holes 18a and 18b. Create a situation.

  That is, the first check valve mechanism 50 is interposed between the first oil chamber 61 and the second oil chamber 62. Such a first check valve mechanism 50 includes a first check valve 51 having an axial flow path 51a, a seat member 52 having a flow path 52a in the central portion, and a first member between the seat member 52 and the first check valve mechanism 50. It mainly includes a rod guide 53 that surrounds the check valve 51 and has a flow path 53a in the center, and an O-ring 54. The first check valve 51 described above is a one-way valve that closes when the hydraulic pressure in the second oil chamber 62 is higher than the hydraulic pressure in the first oil chamber 61.

  Further, the shock absorber 10 includes a second check valve mechanism 70 as shown in FIGS. The second check valve mechanism 70 is interposed between the third oil chamber 63 and the fourth oil chamber 64. That is, the second check valve mechanism 70 biases the second check valve 71 having the orifice 71a and the tapered surface, the seat member 72 having the notch hole 72a, and the second check valve 71 in the closing direction. A trapezoidal spring 73 as a compression coil spring and a valve seat member 74 having a tapered surface that engages with the tapered surface of the second check valve 71 are mainly provided. The second check valve 71 described above is a second one-way valve that closes when the hydraulic pressure in the third oil chamber 63 is higher than the hydraulic pressure in the fourth oil chamber 64.

  Next, the compression side stroke and the extension side stroke of the shock absorber 10 according to the present embodiment configured as above will be described. Here, in FIGS. 2 and 3, the solid arrow line whose tip is filled schematically shows the flow of oil in the compression side stroke, while the broken arrow line whose tip is filled is a stretched line. The flow of the oil of a side stroke is shown roughly.

<Pressure side stroke>
For example, in a state in which all the communication holes 18 a and 18 b are positioned on the upper end side of the first check valve 51, the vehicle body side tube 16 is opposed to the axle side tube 15 while resisting the urging force of the suspension spring 12. For example, it is assumed that the vehicle has entered the state shown in FIG. 3 (a state in which all the communication holes 18a and 18b are located on the lower end side of the first check valve 51).

  In this case, as shown in FIG. 3, the hydraulic pressure of the fourth oil chamber 64 is higher than the hydraulic pressure of the third oil chamber 63 as shown in FIG. Thus, the second check valve 71 opens while resisting the biasing force of the trapezoidal spring 73, the tapered surface of the second check valve 71, the tapered surface of the valve seat member 74, and the tapered surface of the valve seat member 74. Between, the flow path 74a is formed. The third oil chamber 63 and the fourth oil chamber 64 are connected to each other through the flow path 74a and a notch hole 72a in the center of the sheet member 72.

  On the other hand, by reducing the volume of the second oil chamber 62, the hydraulic pressure of the second oil chamber 62 becomes higher than the hydraulic pressure of the first oil chamber 61, and as shown in FIG. Is closed, and the gap between the axial flow path 51a of the first check valve 51 and the central flow path 52a of the seat member 52 is closed. Here, the oil (damper oil) 8 flows from the lower end side in the seat pipe 17 into the chamber 19 through the inside of the rod pipe 18, while from the inside of the rod pipe 18 through the communication holes 18 a and 18 b. Part of the oil 8 returns to the seat pipe 17 (bypass).

  At this time, although the oil 8 passes through the communication holes 18a and 18b, the first check valve 51 is closed, so that the oil 8 cannot flow into the first oil chamber 61. Flow is obstructed. Thereby, the viscous resistance when the oil 8 flows increases, and a compression side damping force is generated.

  Therefore, in the shock absorber 10, in such a pressure side stroke, the relative positional relationship between the axle side tube 15 and the vehicle body side tube 16 in the stroke direction (relative relationship between the first check valve 51 and the communication holes 18a and 18b). Appropriate positional relationship) and the moving speed (speed at which the positional relationship between the first check valve 51 and the communication holes 18a and 18b is displaced) can be obtained, for example, an appropriate compression-side damping force.

  Here, FIG. 8 shows the relationship between the relative position and moving speed in the stroke direction of the axle side tube 15 and the vehicle body side tube 16 provided in the shock absorber 10 of the present embodiment, and the compression side damping force. It is. Note that the relative displacement 5 mm in the stroke direction in FIG. 8 is relative to the axle-side tube 15 and the vehicle-body side tube 16 that serve as a reference when the driver normally travels in a motorcycle equipped with a pair of shock absorbers 10. It is a positional relationship.

  As shown in FIG. 8, in the shock absorber 10, when the moving speed in the stroke direction of the axle side tube 15 and the vehicle body side tube 16 is extremely high (for example, when the moving speed Vp is 0.7 m / s), for example, When the front side of a motorcycle suddenly sinks to the road surface due to sudden deceleration, etc., it is possible to quickly increase the compression side damping force (responsiveness when damping the vibration) and ensure driver safety. it can. That is, according to the shock absorber 10, it is possible to obtain an appropriate damping force (DF: damping force) according to the relative position and moving speed of the axle side tube 15 and the vehicle body side tube 16 in the stroke direction. .

<Stretch side stroke>
For example, in a state where all the communication holes 18a, 18b are located on the lower end side of the first check valve 51, the vehicle body side tube 16 is relatively retracted from the axle side tube 15, and the state shown in FIG. It is assumed that the state has shifted to (a state in which all the communication holes 18a and 18b are located on the upper end side of the first check valve 51).

  In this case, as shown in FIG. 2, as the volume of the third oil chamber 63 is reduced, the hydraulic pressure of the third oil chamber 63 becomes higher than the hydraulic pressure of the fourth oil chamber 64, and as shown in FIG. In addition, the second check valve 71 is closed, and the space between the tapered surface of the second check valve 71, the tapered surface of the valve seat member 74, and the tapered surface of the valve seat member 74 (flow path 74a) is closed. As a result, the oil 8 in the third oil chamber 63 moves to the fourth oil chamber 64 side through the orifice 71a inside the second check valve 71 via the notch flow path 72a of the seat member 72. To do. When the oil 8 passes through the orifice 71a, or when the oil 8 passes through the oil hole 17a shown in FIG.

  On the other hand, as the volume of the first oil chamber 61 is reduced, the oil pressure in the first oil chamber 61 becomes higher than the oil pressure in the second oil chamber 62, and as shown in FIG. As a result, the central flow path 52a of the seat member 52, the axial flow path 51a of the first check valve 51, and the flow path 53a of the rod guide 53 are inserted. Further, the oil 8 in the first oil chamber 61 flows into the rod pipe 18 through the communication holes 18a and 18b.

  The oil 8 that has passed through the orifice 71a and the oil 8 in the second oil chamber 62 pass through the oil holes 17a and 17b provided in the side wall portion on the upper end side of the seat pipe 17 and enter the seat pipe 17 as well. Flows in. Further, the oil 8 in the first oil chamber 61 flows into the seat pipe 17 through a side hole 17 e provided in the side wall portion on the lower end side of the seat pipe 17.

  As described above, according to the shock absorber 10 of the present embodiment, the relative positional relationship between the axle side tube 15 and the vehicle body side tube 16 in the stroke direction, that is, the first check valve 51 and the communication hole 18a, Appropriate damping force (damping force) according to the relative positional relationship with 18b and the relative moving speed in the stroke direction (speed at which the positional relationship between the first check valve 51 and the communication holes 18a and 18b is displaced) ) Can be obtained.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 8 ... Oil, 10 ... Shock absorber, 15 ... Axle side tube, 15a ... Lower end side closing part, 16 ... Vehicle body side tube, 16a ... Lower end side opening part, 16b ... Upper end side closing part, 12 ... Suspension spring, 17 ... Seat Pipe, 17d ... Upper-diameter enlarged portion, 17e ... Side hole, 17f ... Upper end-side opening, 18 ... Rod pipe, 18a, 18b ... Communication hole, 19 ... Chamber, 50 ... First check valve mechanism, 51 ... First 1 check valve, 70 ... second check valve mechanism, 71 ... second check valve, 61 ... first oil chamber, 62 ... second oil chamber, 63 ... third oil chamber, 64 ... fourth No. 65, fifth oil chamber.

Therefore, the problem to be solved by the present invention is to provide a shock absorber capable of obtaining an appropriate damping force according to the relative displacement and moving speed in the stroke direction between the axle side tube and the vehicle body side tube. is there.

It is sectional drawing which shows the structure of the buffer which concerns on this embodiment. It is sectional drawing which expands and shows the state just before extending the buffer of FIG. It is sectional drawing which expands and shows the state just before the most compression of the shock absorber of FIG. FIG. 3 is a cross-sectional view showing a state where a first check valve in FIG. 2 is closed. FIG. 5 is a cross-sectional view showing a state where a first check valve of FIG. 4 is opened. FIG. 3 is a cross-sectional view showing a state where a second check valve in FIG. 2 is closed. It is sectional drawing which shows the state by which the 2nd check valve of FIG. 6 was opened. It is a figure which shows the relationship between the relative displacement and the moving speed of the stroke direction of the axle side tube with which the shock absorber of FIG. 1 was equipped, and the vehicle body side tube, and the compression side damping force.

Moreover, the shock absorber 10 includes first to fifth oil chambers 61, 62, 63, 64, 65 as shown in FIGS. The first oil chamber 61 is disposed between the outer periphery of the inner periphery of the vehicle body side tube 16 and the rod pipe 18. More specifically, the first oil chamber 61 is formed by the inner peripheral side of the vehicle body side tube 16, the outer peripheral side of the rod pipe 18, the first check valve mechanism 50, and the upper end side closing portion 16 b of the vehicle body side tube 16. It is an enclosed oil chamber. The second oil chamber 62 is disposed on the inner peripheral side of the seat pipe 17.

The fourth oil chamber 64 is disposed between the outer periphery of the inner periphery and the sheet Topaipu 17 of the axle side tube 15. More specifically, the fourth oil chamber 64 has a lower end closure 15a of the second check valve mechanism 70 and the axle side tube 15 to be described later to the outer periphery of the inner periphery of the axle side tube 15 and the seat pipe 17 Is an oil chamber surrounded by Further, the fifth oil chamber 65 is disposed on the inner peripheral side of the chamber 19.

The first check valve mechanism 50 is interposed between the first oil chamber 61 and the second oil chamber 62. The first check valve mechanism 50 includes a first check valve 51 having a flow path 51a, a sheet member 52 having a passage 52a in a central portion, a first check valve between the seat member 52 51, a rod guide 53 having a flow path 53a at the center and an O-ring 54 are mainly provided. The first check valve 51 described above is a one-way valve that closes when the hydraulic pressure in the second oil chamber 62 is higher than the hydraulic pressure in the first oil chamber 61.

In this case, as shown in FIG. 3, by the reduction of the volume of the fourth oil chamber 64, the hydraulic pressure of the fourth oil chamber 64, a that higher than the hydraulic pressure of the third oil chamber 63. Then, as shown in FIG. 7, while resisting the urging force of the trapezoidal spring 73, the second check valve 71 opens, the tapered surface of the tapered surface and the valve seat member 74 of the second check valve 71 and In between, the flow path 74a is formed. The third oil chamber 63 and the fourth oil chamber 64 are connected to each other through the flow path 74a and a notch hole 72a in the center of the sheet member 72.

On the other hand, by the reduction of the volume of the second oil chamber 62, hydraulic pressure of the second oil chamber 62, a that higher than the hydraulic pressure of the first oil chamber 61. Then , as shown in FIG. 4, the first check valve 51 is closed, and the flow path 51a of the first check valve 51 and the flow path 52a of the seat member 52 are blocked . Here, the oil (damper oil) 8 flows from the lower end side in the seat pipe 17 into the chamber 19 through the inside of the rod pipe 18, while from the inside of the rod pipe 18 through the communication holes 18 a and 18 b. Part of the oil 8 returns to the seat pipe 17 (bypass).

Therefore, in the shock absorber 10, in such a pressure side stroke, the relative positional relationship between the axle side tube 15 and the vehicle body side tube 16 in the stroke direction ( that is, between the first check valve 51 and the communication holes 18a and 18b). relative positional relationship), and the stroke direction of the relative movement speed (i.e., the first check valve 51 and the communication hole 18a, depending on the speed) the positional relationship between 18b is displaced, an appropriate pressure side damping force Ru can be obtained.

FIG. 8 shows the relationship between the relative displacement and moving speed in the stroke direction between the axle side tube 15 and the vehicle body side tube 16 provided in the shock absorber 10 of the present embodiment, and the compression side damping force. Incidentally, the stroke direction of the relative displacement 5mm in Figure 8, the relative position between the axle side tube 15 and the vehicle body side tube 16 serving as a reference when the normal traveling at motorcycle including a pair of shock absorbers 10 It is a relationship.

As shown in FIG. 8, in the shock absorber 10, when the moving speed in the stroke direction of the axle side tube 15 and the vehicle body side tube 16 is extremely high (for example, when the moving speed Vp is 0.7 m / s), for example, When the front side of a motorcycle suddenly sinks to the road surface due to sudden deceleration, etc., it is possible to quickly increase the compression side damping force (responsiveness when damping the vibration) and ensure driver safety. it can. That is, according to the shock absorber 10, it is possible to obtain an appropriate damping force DF according to the relative displacement and moving speed of the axle side tube 15 and the vehicle body side tube 16 in the stroke direction.

In this case, as shown in FIG. 2, by reduction of the volume of the third oil chamber 63, hydraulic pressure in the third oil chamber 63, a that higher than the hydraulic pressure of the fourth oil chamber 64. Then, as shown in FIG. 6, the second check valve 71 is closed to shut off between the (flow path 74a) between said tapered surface and the tapered surface of the valve seat member 74 of the second check valve 71. As a result, the oil 8 in the third oil chamber 63 moves to the fourth oil chamber 64 side through the orifice 71a inside the second check valve 71 via the notch flow path 72a of the seat member 72. To do. By increasing the viscosity resistance when the orifice 71 a and the oil holes 17a oil 8 passes, the extension side damping force is generated.

On the other hand, an increase in the volume of the second oil chamber 62, hydraulic pressure of the first oil chamber 61, a that higher than the hydraulic pressure of the second oil chamber 62. Then, as shown in FIG. 5, the first check valve 51 opens, connecting thereby, the flow path 52a of the seat member 52 into the flow path 53a of the channel 51a and the rod guide 53 of the first check valve 51 Is done. Further, the oil 8 in the first oil chamber 61 flows into the rod pipe 18 through the communication holes 18a and 18b.

The oil 8 that has passed through the orifice 71a and the oil 8 in the third oil chamber 63 also enter the seat pipe 17 through the oil holes 17a and 17b provided in the wall portion on the upper end side of the seat pipe 17. Flows in. Further, the oil 8 in the fourth oil chamber 64 flows into the seat pipe 17 through the side hole 17e provided in the side wall portion on the lower end side of the seat pipe 17.

As already mentioned, according to the shock absorber 10 of the present embodiment, the stroke direction of the relative positional relationship (that of the axle side tube 15 and the vehicle body side tube 16, the first check valve 51 and the communication hole 18a, the relative position relationship) between 18b, suitable in accordance with the relative moving speed of the stroke direction (i.e., the rate at which the first check valve 51 and the communication hole 18a, the positional relationship between 18b displaced) Ru can get Do damping force.

Claims (6)

An axle side tube that is provided on the axle side, has an upper end side that is open, a lower end side is closed, and oil is sealed;
A check valve mechanism is provided on the partition wall, and a check valve mechanism that is provided upright on the shaft center of the lower end side closing portion of the axle side tube and that has an upper end that opens and expands in diameter. A seat pipe having side holes,
Provided on the vehicle body side, the upper end side is closed, the lower end side is opened, the seat pipe is inserted from the lower end side opening and connected to the axle side tube, and along the axial direction with respect to the axle side tube Body-side tube that moves relatively,
It is erected on the shaft center of the upper end side closing portion of the vehicle body side tube, and is slidably inserted in the axial direction of the seat pipe from the upper end side opening portion of the seat pipe, and a communication hole is formed in the partition wall portion. A hollow rod pipe provided;
A suspension spring provided inside the vehicle body side tube and interposed between an upper end side closing portion of the vehicle body side tube and an upper end portion of the seat pipe;
The shock absorber according to claim 1, wherein the check valve mechanism restricts the flow of oil passing through the communication hole of the rod pipe according to a relative displacement between the axle side tube and the vehicle body side tube.   The check valve mechanism includes a first oil chamber disposed between an inner peripheral side of the vehicle body side tube and an outer peripheral side of the rod pipe, and a second oil disposed on the inner peripheral side of the seat pipe. The shock absorber according to claim 1, wherein the shock absorber is interposed between the two chambers.   The shock absorber according to claim 2, wherein the check valve mechanism includes a one-way valve that closes when a hydraulic pressure of the second oil chamber is higher than a hydraulic pressure of the first oil chamber.   The shock absorber according to any one of claims 1 to 3, wherein a plurality of the communication holes are provided at intervals in the axial direction of the rod pipe.   A third oil chamber disposed between an inner peripheral side of the vehicle body side tube and an outer peripheral side of the seat pipe; and disposed between an inner peripheral side of the axle side tube and an outer peripheral side of the seat pipe. The shock absorber according to any one of claims 1 to 4, further comprising a second check valve mechanism interposed between the fourth oil chamber and the fourth oil chamber.   6. The second check valve mechanism includes a second one-way valve that closes when a hydraulic pressure of the third oil chamber is higher than a hydraulic pressure of the fourth oil chamber. Shock absorber.

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