Hydraulic shock absorber

Abstract

A hydraulic shock absorber (10) comprises a control valve (50) that exerts flow path resistance on hydraulic oil flowing from an opening (16d) of a rod (16) to a reservoir (22), and a guide element (70) that directs the hydraulic oil introduced from the opening (16d) to the control valve (50). The control valve (50) comprises a valve body (53) located on a centerline (CL) of the rod (16) and displaced along the centerline (CL). The guide element (70) is located between an upper end (16e) of the rod (16) and the control valve (50) and on the centerline (CL). An oil inlet (73) of the guide element (70) is located radially outside an outer circumferential surface (16f) of the rod (16) and can introduce the hydraulic oil from the opening (16d).

Description

TECHNICAL AREA

[0001] The present invention relates to a hydraulic shock absorber, which is particularly suitable for use in a semi-trailer vehicle on which a driver sits in the saddle. BACKGROUND OF THE TECHNOLOGY

[0002] A hydraulic shock absorber, in which a vehicle body-side tube and a wheel-side tube are telescopically designed, is used for a suspension device mounted on a semi-trailer vehicle, such as a two-wheeled or three-wheeled vehicle. For example, a hydraulic shock absorber, in which a cylinder is provided in a wheel-side tube, a rod carrying a piston in sliding contact with the cylinder is provided in a vehicle body-side tube, and a control valve is provided in an upper section of a vehicle body-side tube, is known from patent literature 1 and patent literature 2.

[0003] In the hydraulic shock absorbers disclosed in patent literature 1 and patent literature 2, a passage is formed within the rod, having an opening at an upper end of the rod and a lower opening in the cylinder, and the control valve is provided on an upper section of the tube facing the vehicle body. The control valve exerts a flow path resistance on hydraulic oil flowing from the opening at the upper end of the passage to a reservoir. The damping force of the hydraulic shock absorber can be adjusted by controlling the opening and closing of the control valve. CITATION LIST PATENT LITERATURE Patent literature 1: JP5452434B Patent Literature 2: JP2017-180689A SUMMARY OF THE INVENTIONAL TASK OF THE INVENTION

[0004] In the hydraulic shock absorber known from patent literature 1, a control valve body is located directly above the opening at the upper end of the rod and is offset along a centerline of the rod. The hydraulic oil discharged upwards from the opening at the upper end of the rod directly impacts the valve body. The flow of the hydraulic oil changes (i.e., pulsates) according to the expansion and contraction operation of the hydraulic shock absorber. Since the flow velocity of the hydraulic oil discharged from the opening is constantly changing, the discharge pressure of the hydraulic oil also fluctuates constantly. To prevent the fluctuation in the discharge pressure from affecting the operation of the control valve, this results in stable control of the damping force by the control valve.

[0005] On the other hand, in the hydraulic shock absorber known from patent literature 2, the valve body of the control valve is located at the upper end of the rod, but is positioned at an angle to the rod's centerline. Therefore, the hydraulic oil discharged upwards from the opening at the upper end of the rod does not directly impact the valve body. Fluctuations in the discharge pressure can thus be prevented from affecting the operation of the control valve. This makes it possible to improve the stability of the damping force control by the control valve. However, because the control valve is positioned at an angle, the configuration of the hydraulic shock absorber is inevitably complex, which is detrimental to cost reduction and also to reducing the size of the hydraulic shock absorber in the radial direction.

[0006] One object of the present invention is to provide a technique capable of improving the stability of the control of a damping force by a control valve of a hydraulic shock absorber, which includes the control valve, and of reducing the cost and size of the hydraulic shock absorber. MEANS OF SOLVING THE TASK

[0007] As a result of intensive studies, the present inventors focused on the fact that the discharge direction of hydraulic oil dispensed from an upper section of a tubular rod can be changed. It was then determined that the flow direction of the discharged hydraulic oil can be directed in a direction that does not affect the operation of a control valve without tilting the control valve. The present invention was developed based on these results.

[0008] According to the present disclosure, a hydraulic shock absorber is provided, comprising: a telescopic vehicle body-side tube and a telescopic wheel-side tube, each arranged on a vehicle body side and a wheel side, respectively; a cylinder extending from a lower end section of the wheel-side tube to an inner side of the vehicle body-side tube; a reservoir located outside the cylinder and configured to store hydraulic oil; a rod extending from an upper end section of the vehicle body-side tube to an inner side of the cylinder, the rod being a tubular element configured to allow the hydraulic oil to pass through it, and the rod having an opening at an upper section configured to allow the hydraulic oil to be discharged radially outwards;a piston provided at a lower end section of the rod and dividing the inside of the cylinder into two oil chambers; a control valve provided at the upper end section of the tube on the vehicle body side, including a valve body located on a centerline of the rod and displaceable along the centerline, and configured to exert flow path resistance on the hydraulic oil flowing from the opening of the rod to the reservoir by means of a displacement of the valve body;and a guide element located between an upper end of the rod and the control valve and on the centerline of the rod, comprising an oil inlet located radially outside an outer circumferential surface of the rod and configured to introduce hydraulic oil from the opening of the rod, an oil outlet configured to direct hydraulic oil to the control valve, and a first guide path that directs the hydraulic oil introduced from the oil inlet to the oil outlet. EFFECTS OF THE INVENTION

[0009] In the present disclosure it is possible to provide a technique that is able to improve the stability of a control of the damping force by the control valve of the hydraulic shock absorber, which includes the control valve, and to reduce the cost and size of the hydraulic shock absorber. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a cross-sectional side view of a main part of a hydraulic shock absorber according to embodiment 1. Fig. Figure 2 is a schematic diagram of a hydraulic circuit of the hydraulic shock absorber, which is located in Fig. 1 is illustrated. Fig. 3 is an enlarged view of part 3 of Fig. 1. Fig. 4 is an enlarged view of part 4 of Fig. 3. Fig. 5A is an expanded perspective view of an upper end section of a rod, a check valve, and a guide element, shown in Fig. 4 are illustrated, Fig. 5B is a cross-sectional view of the guide element along an arrow line 5B-5B in Fig. 5A, Fig. 5C is a cross-sectional view of the guide element along an arrow line 5C-5C in Fig. 5A and Fig. 5D is a perspective view of another example of an opening that is in Fig. 5A is illustrated. Fig. Figure 6 is a view illustrating the flow of hydraulic oil from the rod to a valve receiver section located in Fig. 4 is illustrated. Fig. 7 is a view showing the flow of hydraulic oil from the valve intake section, which is in Fig. 4 illustrates a reservoir. Fig. Figure 8 is a cross-sectional view around a guide element and a control valve of a hydraulic shock absorber according to embodiment 2. Fig. 9A is a cross-sectional view of the guide element, which is located in Fig. 8 is illustrated, Fig. 9B is a perspective view of the guide element from one direction of an arrow line 9B in Fig. 9A considered and Fig. 9C is a perspective view of the guide element from one direction of an arrow line 9C in Fig. 9A considered. EXECUTIONAL FORMS FOR IMPLEMENTING THE INVENTION

[0010] Embodiments of the present invention are described below with reference to the accompanying drawings. The embodiments illustrated in the accompanying drawings are examples of the present invention, and the present invention is not limited to these embodiments. In the description, "top" and "bottom" refer to upper and lower directions based on a condition in which a hydraulic shock absorber is mounted on a semi-trailer truck. "Top" in the drawings indicates an upper direction, and "bottom" in the drawings indicates a lower direction. <Ausführungsform 1>

[0011] A hydraulic shock absorber 10 according to embodiment 1 is described with reference to the Fig. 1 to Fig. 7 described.

[0012] As in Fig. As illustrated in Figure 1, the hydraulic shock absorber 10 is used, for example, in a vehicle, and is used, for instance, in a motorcycle, which is a type of saddle vehicle (not shown) on which a rider sits in a saddle. Hereinafter, the motorcycle can be referred to as the "saddle vehicle" or "vehicle".

[0013] The hydraulic shock absorber 10 is telescopic and comprises a cylindrical vehicle body-side tube 11 (first tube 11) connected to a vehicle body-side bracket (not shown) and a cylindrical axle-side tube 13 (second tube 13) connected to an axle-side bracket 12.

[0014] The axle-side tube 13 is fitted so that it is movable relative to the vehicle body-side tube 11. A coil spring 14, which biases the vehicle body-side tube 11 and the axle-side tube 13 away from each other in one direction, is arranged inside the axle-side tube 13.

[0015] Here, a stroke in which the hydraulic shock absorber 10 is compressed is referred to as a compression stroke, and a stroke in which the hydraulic shock absorber 10 expands is referred to as an expansion stroke. In embodiment 1, it is described that the hydraulic shock absorber 10 has a reversed configuration in which the axle-side tube 13 is advanced and retracted relative to the vehicle body-side tube 11. However, the hydraulic shock absorber 10 also includes an upright configuration in which the vehicle body-side tube 11 is advanced and retracted relative to the axle-side tube 13.

[0016] The hydraulic shock absorber 10 comprises a cylinder 15 extending from a lower end section 13a (for example, the axle-side bracket 12) of the wheel-side tube 13 to the inside of the vehicle body-side tube 11, and a rod 16 extending from an upper end section 11a of the vehicle body-side tube 11 to the inside of the cylinder 15. The inside of the cylindrical cylinder 15 is filled with hydraulic oil. The upper end section 11a of the vehicle body-side tube 11 is closed, for example, by a closing element 17 (cap element 17). The rod 16 is a tubular element, i.e., a so-called hollow rod, through which the hydraulic oil can flow to the interior 16b (inner flow path 16b). A lower end section 16c of the rod 16 is provided with a piston 21 which divides the inside of the cylinder 15 into two oil chambers 18, 19 (an upper first oil chamber 18 and a lower second oil chamber 19).The vehicle body-side tube 11, the axle-side tube 13, the cylinder 15, the rod 16 and the piston 21 are all located on the center line CL of the rod 16.

[0017] The hydraulic shock absorber 10 further comprises a reservoir 22, defined outside the cylinder 15, and a damping force generating device 23, provided at the upper end section 11a of the vehicle body-side tube 11. The reservoir 22 is a space defined outside the cylinder 15, surrounded by the vehicle body-side tube 11 and the axle-side tube 13, and can store the hydraulic oil. The damping force generating device 23 is provided, for example, at the locking element 17 and is located on the centerline CL of the rod 16. The damping force generating device 23 comprises a control valve 50, the opening area of ​​which can be varied, and an actuator 40 that controls the control valve 50. The control valve 50 functions as a variable throttle valve. Details of the damping force generating device 23 are described later.

[0018] Here, the flow of hydraulic oil in the hydraulic shock absorber 10 is described with reference to Fig. 2 described. Fig. Figure 2 illustrates a hydraulic circuit of the hydraulic shock absorber 10.

[0019] The cylinder 15 includes a base valve 31 at an end section on one side of the shaft. The base valve 31 comprises a compression-side damping valve 32, a compression-side throttle flow path 33, and an expansion-side check valve 34. The compression-side damping valve 32 can generate a damping force when the hydraulic oil flowing from the lower second oil chamber 19 to the reservoir 22 passes through the compression-side throttle flow path 33 during the compression stroke of the hydraulic shock absorber 10. The expansion-side check valve 34 allows the hydraulic oil to flow from the reservoir 22 to the lower second oil chamber 19 during the expansion stroke of the hydraulic shock absorber 10.

[0020] The piston 21 comprises an expansion-side damping valve 35, an expansion-side throttle flow path 36, and a compression-side check valve 37. The expansion-side damping valve 35 can generate a damping force when the hydraulic oil flowing from the upper first oil chamber 18 to the lower second oil chamber 19 passes through the expansion-side throttle flow path 36 during the expansion stroke of the hydraulic shock absorber 10. The compression-side check valve 37 allows the flow of hydraulic oil from the second oil chamber 19 to the first oil chamber 18 during the compression stroke of the hydraulic shock absorber 10.

[0021] The rod 16 has an opening 16d capable of discharging hydraulic oil into an upper end section 16a. Furthermore, the rod 16 includes a flow direction device 38 with a check valve structure. Only when the pressure in the upper first oil chamber 18 is higher than the pressure in the reservoir 22 does the flow direction device 38 allow the hydraulic oil to flow from the first oil chamber 18 through an inlet path 39 into the inner flow path 16b of the rod 16.

[0022] When the hydraulic shock absorber 10 is in its extension stroke (when the cylinder 15 expands in the direction of arrow Re with respect to the piston 21), the volume of the upper first oil chamber 18 decreases, and the volume of the lower second oil chamber 19 increases. The pressure in the first oil chamber 18 is higher than the pressure in the reservoir 22. The flow straightening device 38 of the rod 16 allows the hydraulic oil to flow from the first oil chamber 18 to the inner flow path 16b of the rod 16. The hydraulic oil in the first oil chamber 18 passes through the inner flow path 16b of the rod 16, is discharged through the opening 16d, and flows via the control valve 50 to the reservoir 22. When the control valve 50 exerts flow path resistance on the hydraulic oil, a damping effect occurs. Part of the excess hydraulic oil in the first oil chamber 18 passes through a damping valve 28 and flows out to the second oil chamber 19.At this point, the damping effect occurs through the expansion-side throttling flow path 36. The hydraulic oil stored in reservoir 22 flows through the check valve 33 into the second oil chamber 19 with the increased volume.

[0023] When the hydraulic shock absorber 10 is in its compression stroke (when the cylinder 15 compresses in the direction of arrow Rc with respect to the piston 21), the volume of the upper first oil chamber 18 increases, and the volume of the lower second oil chamber 19 decreases. The hydraulic oil in the second oil chamber 19 flows out through the compression-side damping valve 32 to the reservoir 22. At this point, the damping effect is generated by the compression-side throttle flow path 33. However, the flow resistance of the hydraulic oil passing through the compression-side throttle flow path 33 is greater than the flow resistance of the hydraulic oil passing through a check valve 30. Therefore, some of the hydraulic oil from the second oil chamber 19 flows through the check valve 30 into the first oil chamber 18.

[0024] When the hydraulic oil flowing from the second oil chamber 19 into the first oil chamber 18 increases, the pressure in the first oil chamber 18 becomes higher than the pressure in the reservoir 22. When the pressure in the first oil chamber 18 exceeds the pressure in the reservoir 22, the flow guide 38 of the rod 16 directs the flow of hydraulic oil from the first oil chamber 18 to the inner flow path 16b of the rod 16. The hydraulic oil in the first oil chamber 18 passes through the inner flow path 16b of the rod 16, is discharged from the opening 16d, and flows out to the reservoir 22 via the control valve 50. When the control valve 50 exerts flow path resistance on the hydraulic oil, the damping effect occurs.

[0025] As can be seen from the preceding description, during both the compression and extension strokes of the hydraulic shock absorber 10, the hydraulic oil in the first oil chamber 18 passes through the internal flow path 16b of the rod 16, is discharged from the opening 16d, and flows via the control valve 50 to the reservoir 22. When the control valve 50 exerts flow path resistance on the hydraulic oil, a damping effect occurs in the hydraulic shock absorber 10.

[0026] Next, the damping force generating device 23 will be described in detail. Fig. Figure 3 illustrates the damping force generating device 23, which is provided in an upper section of the vehicle body-side tube 11.

[0027] The actuator 40 and the control valve 50 of the damping force generating device 23 are located on the center line CL of the rod 16. The actuator 40 is preferably equipped with an electromagnetic solenoid including an actuating rod 42. The actuator 40 may optionally be referred to as the "electromagnetic solenoid 40".

[0028] The electromagnetic solenoid 40 (actuator 40) is a so-called proportional solenoid, in which the current supplied to an excitation coil (not shown) is proportional to the travel distance (advance / retraction amount) of a piston 41. Furthermore, the electromagnetic solenoid 40 is formed by a pressure solenoid that moves the piston 41 forward by energizing the excitation coil. The piston 41 includes the actuating rod 42 (valve rod 42), which is located on the centerline CL of the rod 16. The valve rod 42 can move forward and backward together with the piston 41 in one direction along the centerline CL of the rod 16. As described above, since the electromagnetic solenoid 40 is a proportional solenoid, the opening degree of the control valve 50 can be set according to the travel distance of the piston 41 and the valve rod 42.

[0029] A housing 43 of the electromagnetic solenoid 40 accommodates the excitation coil and the piston 41. By attaching the upper end section of the housing 43 to the locking element 17, the electromagnetic solenoid 40 can be attached to the upper end section 11a of the vehicle body-side tube 11. The housing 43 of the electromagnetic solenoid 40 can optionally be referred to as the "actuator housing 43" or "first housing 43". An opening at the lower end of the first housing 43 is closed by a cover 44. The cover 44 is attached to the first housing 43.

[0030] As in Fig. As illustrated in Figure 4, the control valve 50 is detachably attached to a lower end of an inner circumferential surface 43a of the first housing 43. The control valve 50 comprises a valve body holder 51, which is located below the cover 44 of the actuator 40, and a tubular valve body 52 with a base, which is located below the valve body holder 51. The valve body holder 51 holds the valve body 53, which is located on the centerline CL of the rod 16. The valve body 53 is movable along the centerline CL by being pushed by the valve rod 42.

[0031] The valve housing 52 may optionally be referred to as the "second housing 52". The second housing 52 is detachably attached to the lower end of the inner circumferential surface 43a of the first housing 43 together with the valve body holder 51. An opening at an upper end of the second housing 52 is closed by the valve body holder 51. A valve receiving section 54 (receiving chamber 54) is defined internally by the valve body holder 51 and the second housing 52.

[0032] A side wall 52a of the second housing 52 has a cylindrical shape with respect to the center line CL of the rod 16. The side wall 52a has at least one first opening 52b extending through it to allow a connection between the valve receiving section 54 and the outside.

[0033] A base plate 52c of the second housing 52 has a flat, plate-like shape perpendicular to the center line CL of the rod 16. The base plate 52c has a second opening 52d extending through it to allow a connection between the valve receiving section 54 and the outside. The second opening 52d is located on the center line CL of the rod 16. Furthermore, the base plate 52c of the second housing 52 includes a valve seat 55 facing the valve body 53. The valve seat 55 has a through-hole 55a extending vertically. The through-hole 55a connects the valve receiving section 54 to the second opening 52d.

[0034] The opening degree of the control valve 50 changes according to the amount of movement of the valve body 53 relative to the valve seat 55. The amount of damping force generated by the control valve 50 can be adjusted by setting the amount of movement of the valve body 53 by the electromagnetic solenoid 40. The valve body 53 is biased away from the valve seat 55 by a coil spring 56.

[0035] As in Fig. As illustrated in Figure 4, the control valve 50 can be configured to adjust the amount of damping force generated by a plurality of plate-shaped valve plates 57 stacked in the direction along the centerline CL of the rod 16. The presence or absence of the valve plate 57 is arbitrary.

[0036] The multitude of valve plates 57 are arranged at predetermined intervals in the direction along the centerline CL of the rod 16. Fig. Figure 4 does not illustrate the intervals between the valve plates 57. Each valve plate 57 is elastically deformable in the direction along the centerline CL. When the valve body 53 moves in the direction along the centerline CL and pushes each valve plate 57 towards the valve seat 55, the interval between the valve plates 57 decreases. By changing the interval between the valve plates 57 by adjusting the amount of movement of the valve body 53, the amount of damping force generated by the control valve 50 can be adjusted. Each valve plate 57 is biased by the coil spring 56 in a direction away from the valve seat 55 via a valve retaining section 58.

[0037] As in Fig. As illustrated in Figure 3, a tubular rod holder 60 with a detachable base is attached to a lower end of an outer circumferential surface 43b of the first housing 43. The rod holder 60 is located inside the first tube 11 together with the first housing 43. The side wall 61 of the rod holder 60 has a cylindrical shape with respect to the center line CL of the rod 16. A base plate 62 of the rod holder 60 has a flat disc shape orthogonal to the center line CL of the rod 16. A valve receiving section 63 (receiving chamber 63) is defined inside by the cover 44 and the rod holder 60. The control valve 50 is housed in the valve receiving section 63. The first opening 52b of the second housing 52 of the control valve 50 is communicatively connected to the valve receiving section 63.

[0038] The side wall 61 of the rod holder 60 has at least one connecting hole 64 that extends through it. The connecting hole 64 communicates between the reservoir 22 in the first tube 11 and the valve receiving section 63.

[0039] The upper end section 16a of the rod 16 is detachably attached to the base plate 62 of the rod holder 60. Consequently, the upper end section 16a of the rod 16 is secured to the upper end section 11a of the vehicle body-side tube 11 by the locking element 17, the first housing 43, and the rod holder 60.

[0040] As in Fig. As illustrated in Figure 4, the opening 16d, located at the upper end section 16a of the rod 16, extends in the radial direction of the rod 16. Therefore, the hydraulic oil flowing through the inner flow path 16b of the rod 16 can be discharged radially outwards from the opening 16d.

[0041] A guide element 70, which guides the hydraulic oil, is arranged between an upper end 16e (upper end face 16e) of the rod 16 and the control valve 50. The guide element 70 is housed in the valve receiving section 63, is located on the centerline CL of the rod 16, and is sandwiched between the base plate 52c of the second housing 52 and the base plate 62 of the rod holder 60. The guide element 70 has a disc shape that can be fitted into an inner circumferential surface 61a of the side wall 61 of the rod holder 60.

[0042] Both end faces 71, 72 (an upper first end face 71 and a lower second end face 72) of the guide element 70 are flat surfaces orthogonal to the center line CL of the rod 16. Furthermore, a bottom surface 52e of the base plate 52c of the second housing 52 and an inner bottom surface 62a of the base plate 62 of the rod holder 60 are also flat surfaces orthogonal to the center line CL of the rod 16. Therefore, both end faces 71, 72 of the guide element 70 are in close contact with the bottom surface 52e and the inner bottom surface 62a. The upper end face 16e of the rod 16 is closed by the second end face 72 of the guide element 70, which is in close contact with the second end surface 72.

[0043] Recesses 65, 66, formed in two stages along the centerline CL of the rod 16, are provided in the base surface 62a of the base plate 62 of the rod holder 60. These recesses 65, 66 have a circular shape with respect to the centerline CL. In a state where the upper end surface 16e of the rod 16 is in contact with the second end surface 72 of the guide element 70, the base surface 65a of the upper first recess 65, which is located directly below the base surface 52e, is at least in a higher position than the opening 16d of the rod 16. The diameter of the first recess 65 is preferably larger than the diameter of the second housing 52.Furthermore, in a state where the upper end face 16e of the rod 16 is in contact with the second end face 72 of the guide element 70, the bottom surface 66a of the lower second recess 66, which is located directly below the first recess 65, is at least in a lower position than the opening 16d of the rod 16. The diameter of the second recess 66 is smaller than the diameter of the first recess 65.

[0044] As in Fig. 4 and Fig. 5A to Fig. As illustrated in Figure 5C, the guide element 70 comprises oil inlets 73, oil outlets 74, first guide paths 75 which are communicatively connected from the oil inlets 73 to the oil outlets 74, and a second guide path 76 which is separate from the first guide paths 75.

[0045] The oil inlet 73 is located radially outside an outer circumferential surface 16f of the rod 16 and can introduce hydraulic oil from the opening 16d of the rod 16. That is, the oil inlet 73 opens towards the lower second end surface 72 and communicates with the first recess 65. The oil outlet 74 is able to discharge the hydraulic oil to the control valve 50 and is located radially outside the control valve 50. That is, it is preferred that the oil outlet 74 communicates with the valve receiving section 63 and is located radially outside the second housing 52. The first guide path 75 can guide the hydraulic oil introduced from the oil inlet 73 to the oil outlet 74. The first guide path 75 extends in the longitudinal direction of the rod 16 (for example, in the direction along the centerline CL of the rod 16).

[0046] The second guide path 76 can guide the hydraulic oil flowing from the control valve 50 to the reservoir 22 and is separate from the first guide path 75. For example, the second guide path 76 includes a vertical, perforated first hole 77 located on the centerline CL of the rod 16, and a horizontal, perforated second hole 78 that intersects the centerline CL of the first hole 77. The first hole 77 is configured to open the side of the control valve 50 and close the side of the lower second end face 72. The first hole 77 is communicatively connected to the second opening 52d of the second housing 52. At least a portion of the control valve 50, for example, a projecting section 52f extending downwards from the base plate 52c of the second housing 52, is fitted into the first hole 77 of the guide element 70. The second hole 78 extends towards an outer circumferential surface 79 of the guide element 70.Thus, the second guide path 76 extends in the radial direction of the rod 16.

[0047] The guide element 70 comprises an annular groove 81 and a sealing groove 82, which extend over the entire circumference of the outer circumferential surface 79. The annular groove 81 is located near the lower second end surface 72 and is in communicative contact with the second guide path 76. The sealing groove 82 is located near the upper first end surface 71, and a sealing element 83, such as an O-ring, is fitted into it. The sealing element 83 can seal between the receiving chamber 63, in which the control valve 50 is housed, and the reservoir 22.

[0048] As in Fig. 4 and Fig. As illustrated in Figure 5A, a hollow, disc-shaped check valve 91 is arranged in the upper first recess 65. The check valve 91 is fitted into the upper end section 16a of the rod 16 in such a way that it is relatively movable. It is positioned on the bottom surface 65a of the first recess 65 and allows only the flow of hydraulic oil from the opening 16d of the rod 16 to the control valve 50. That is, in a normal state, when hydraulic oil is not being discharged from the opening 16d of the rod 16 (for example, while the actuator 40 is stopped), the check valve 91 is held by its own weight on the bottom surface 65a to close the lower second recess 66. Conversely, when hydraulic oil is being discharged from the opening 16d, the pressure from the hydraulic oil pushes the check valve 91 upwards to open the second recess 66.

[0049] The formation of the opening 16d of the rod 16, which is in Fig. As illustrated in 5A, it is not limited to a round hole and can, for example, be as shown in Fig. 5D illustrates a notch extending to the upper end face 16e of the rod 16.

[0050] Next, the flow of hydraulic oil from rod 16 to reservoir 22 is described. As in Fig. As illustrated in Figure 6, the hydraulic oil flowing through the inner flow path 16b of the rod 16 flows in the direction of arrow Q1. This means that the hydraulic oil flowing through the inner flow path 16b is discharged from the opening 16d of the rod 16, enters the lower second recess 66, pushes the check valve 91 upwards, enters the upper first recess 65, and enters the oil inlet 73. Furthermore, the hydraulic oil passes through the first guide path 75 from the oil inlet 73, flows out of the oil outlet 74, and enters the valve receiving section 63.

[0051] As in Fig. As illustrated in Figure 7, the hydraulic oil that has entered the valve receiving section 63 flows in the direction of arrow Q2. That is, the hydraulic oil encounters flow path resistance when it passes between the valve body 53 and the valve seat 55, through the through-hole 55a of the valve seat 55 and the second opening 52d of the second housing 52, and then enters the second guide path 76. Furthermore, the hydraulic oil flows from the first hole 77 through the second hole 78 of the second guide path 76 and flows out of the annular groove 81 of the guide element 70 to the reservoir 22. <Ausführungsform 2>

[0052] A hydraulic shock absorber 100 according to embodiment 2 is described with reference to the Fig. 8 and Fig. 9 described.

[0053] Fig. Figure 8 is a cross-sectional view illustrating the hydraulic shock absorber 100 according to embodiment 2, and corresponds to Fig. 4, which illustrates the hydraulic shock absorber 10 according to embodiment 1. The hydraulic shock absorber 100 according to embodiment 2 is characterized in that the guide element 70 according to embodiment 1, which is in Fig. As illustrated in section 4, it is changed into a guide element 170, which is located in the Fig. 8 and Fig. Figure 9 illustrates this. Other basic configurations are the same as those of the hydraulic shock absorber 10 according to embodiment 1. Components common to the hydraulic shock absorber 10 according to embodiment 1 are designated by the same reference numerals, and a detailed description thereof is omitted.

[0054] In the guide element 170 according to embodiment 2, a portion of a lower half 179a (a section 179a on the side of the lower second end surface 72) of an outer circumferential surface 179 along the centerline CL of the rod 16 is cut out. As a result, a pair of end surfaces 179b, 179b are formed in the lower half 179a of the guide element 170. These end surfaces 179b, 179b are flat surfaces parallel to the centerline CL and face each other with respect to the centerline CL. A distance Le between the end surfaces 179b, 179b is less than a diameter Dg of the guide element 170.

[0055] The guide element 170 according to embodiment 2 comprises a pair of oil inlets 173, 174, an oil outlet 174, and a first guide path 175 that is communicatively connected from the oil inlets 173 to the oil outlet 174. The guide element 170 according to embodiment 2 need not include the second guide path 76, which is contained in the guide element 70 according to embodiment 1, which is in Fig. 4 is illustrated.

[0056] The pair of oil inlets 173, 173, each opening in the pair of end faces 179b, 179b, are located radially outside the outer circumferential surface 16f of the rod 16 and can introduce hydraulic oil from the opening 16d of the rod 16. The oil outlet 174 can discharge the hydraulic oil to the control valve 50 and is located on the centerline CL of the rod 16. That is, the oil outlet 174 is communicatively connected to the through-hole 55a of the valve seat 55. The first guide path 175 comprises a horizontal, perforated first passage 175a, extending from the oil inlets 173, 173 in the direction intersecting the centerline CL of the rod 16, and a vertical, perforated second passage 175b, extending from the first passage 175a to the oil outlet 174. The second pass 175b is located on the center line CL of pole 16.

[0057] Next, the flow of hydraulic oil from rod 16 to reservoir 22 in embodiment 2 is described. As in Fig. As illustrated in Figure 8, the hydraulic oil flowing through the inner flow path 16b of the rod 16 flows in the direction of arrow Q3. This means that the hydraulic oil flowing through the inner flow path 16b is discharged from the opening 16d of the rod 16, enters the lower second recess 66, pushes the check valve 91 upwards, enters the upper first recess 65, and enters the oil inlet 173. Furthermore, the hydraulic oil passes through the first guide path 175 from the oil inlets 173, flows out of the oil outlet 174, and enters the through-hole 55a of the valve seat 55.

[0058] The hydraulic oil that has entered the through-hole 55a receives the flow path resistance when the hydraulic oil passes between the valve body 53 and the valve seat 55, passes through the first opening 52b of the second housing 52 and the valve receiving section 63, and then flows out of the connecting hole 64 of the rod holder 60 to the reservoir 22.

[0059] The operation and effect of the hydraulic shock absorber 100 according to embodiment 2 are the same as those of the hydraulic shock absorber 10 according to embodiment 1.

[0060] The hydraulic shock absorbers 10, 100 described above are summarized as follows.

[0061] It will be directed to the Fig. 1 and Fig. 8 Reference is made to. (1) According to the present embodiment, the hydraulic shock absorbers 10, 100 each comprise the telescopic vehicle body-side tube 11 and the telescopic wheel-side tube 13, which are arranged on the vehicle body side and the wheel side respectively, the cylinder 15, which extends from the lower end section 13a of the wheel-side tube 13 to the inside of the vehicle body-side tube 11, and the reservoir 22, which is located outside the cylinder 15 and is able to store the hydraulic oil.

[0062] It will be on Fig. 1 Referenced. The hydraulic shock absorbers 10, 100 each comprise the rod 16, which extends from the upper end section 11a of the vehicle body-side tube 11 to the inside of the cylinder 15, is a tubular element designed to allow the hydraulic oil to pass through it, and has the opening 16d, designed to allow the hydraulic oil to be discharged radially outwards, at its upper section, and the piston 21, which is provided at the lower end section 16c of the rod 16 and divides the inside of the cylinder 15 into two oil chambers 18, 19.

[0063] It will be directed to the Fig. 1 and Fig. 3 Referenced. The hydraulic shock absorbers 10, 100 each comprise the control valve 50, which is provided on the upper end section 11a of the vehicle body-side tube 11, comprising the valve body 53, which is located on the centerline CL of the rod 16 and is displaceable along the centerline CL, and exerts flow path resistance on the hydraulic oil which flows from the opening 16d of the rod 16 to the reservoir 22 by a displacement of the valve body 53.

[0064] It will be directed to the Fig. 4 and Fig.8 Referenced. The hydraulic shock absorbers 10, 100 comprise the guide elements 70, 170, which are located between the upper end 16e (upper end surface 16e) of the rod 16 and the control valve 50 and on the centerline CL of the rod 16, and comprise the oil inlets 73, 173, which are located radially outside the outer circumferential surface 16f and are able to introduce the hydraulic oil from the opening 16d of the rod 16, the oil outlets 74, 174, which can carry the hydraulic oil out to the control valve 50, and the first guide paths 75, 175, which carry the hydraulic oil introduced from the oil inlets 73, 173 to the oil outlets 74, 174.

[0065] As described above, since the tubular rod 16 has the opening 16d through which the hydraulic oil can be discharged radially outwards at the upper section, the discharge direction of the hydraulic oil discharged from the upper section of the rod is changed to a radial outward direction from the upper end of the rod. The guide element 70 comprises the first guide path 75, which directs the hydraulic oil discharged from the opening 16d of the rod 16 to the control valve 50. For example, the first guide path 75 can direct the hydraulic oil discharged from the opening 16d of the rod 16 to the control valve 50 while bypassing the hydraulic oil on the radial outside of the control valve 50. Therefore, even if the control valve 50 is not inclined with respect to the centerline CL of the rod 16, the flow direction of the hydraulic oil discharged from the opening 16d of the rod 16 can be directed in a direction that does not affect the operation of the control valve 50.Therefore, the stability of the control of the damping force by the control valve 50 of the hydraulic shock absorber 10, which includes the control valve 50, can be improved, and the cost and size of the hydraulic shock absorber 10 can be reduced.

[0066] In the hydraulic shock absorber 10 according to (1), the guide element 70 preferably comprises the second guide path 76, which guides the hydraulic oil flowing from the control valve 50 to the reservoir 22. The first guide path 75 extends in the longitudinal direction of the rod 16 (for example, along the centerline CL of the rod 16). The second guide path 76 extends in the radial direction of the rod 16 and is separate from the first guide path 75.

[0067] As described above, the second guide path 76, which carries the hydraulic oil from the control valve 50 to the reservoir 22, is separate from the first guide path 75, which extends longitudinally and radially along the rod 16. That is, the first guide path 75 and the second guide path 76 are independent of each other and have different directions of hydraulic oil flow. Therefore, the second guide path 76 can be located within a section of the guide element 70 in the same direction as the first guide path 75. Thus, although the guide element 70 encompasses both the first guide path 75 and the second guide path 76, a portion of its length in the direction of the first guide path 75 can be restricted. By reducing the size of the guide element 70, the overall size of the hydraulic shock absorber 10, which includes the control valve 50, can be reduced.

[0068] In the hydraulic shock absorber 10 according to (1) and (2), the guide element 70 preferably comprises the annular groove 81, which extends over the entire circumference of the outer circumferential surface 79. The annular groove 81 is communicatively connected to the second guide path 76. Therefore, the hydraulic oil can be guided from the control valve 50 to the reservoir 22 regardless of the orientation of the second guide path 76 with respect to the centerline CL of the rod 16. This improves the ease of assembly of the guide element 70 on the hydraulic shock absorber 10.

[0069] In the hydraulic shock absorber 10 according to (2) and (3), the oil outlet 74 is preferably located radially outside the control valve 50. Therefore, the hydraulic oil discharged from the opening 16d of the rod 16 can be directed to the control valve 50, while bypassing the hydraulic oil on the radial outside of the control valve 50. The stability of the damping force control by the control valve 50 can be further improved.

[0070] In the hydraulic shock absorber 10 according to (1) to (4), the guide element 70 preferably comprises the sealing element 83, which seals between the receiving chamber 63, in which the control valve 50 is housed, and the reservoir 22. Therefore, the sealing element 83 can prevent the hydraulic oil, which is not controlled by the control valve 50, from escaping from the receiving chamber 63 to the reservoir 22. The stability of the damping force control by the control valve 50 can thus be further improved.

[0071] In the hydraulic shock absorbers 10, 100 according to (1) to (5), at least a part of the control valve 50 (the preceding section 52f of the second housing 52) is preferably fitted into the guide element 70. Therefore, the guide element 70 can be easily positioned with respect to the control valve 50. Furthermore, since the control valve 50 is fitted into the guide element 70, the axial length of the hydraulic shock absorber 10 can be reduced.

[0072] In the hydraulic shock absorber 10 according to (1) to (6), the hydraulic shock absorbers 10, 100 preferably each include the check valve 91, which allows only the flow of hydraulic oil from the opening 16d of the rod 16 to the control valve 50. Therefore, when the hydraulic oil is not flowing from the opening 16d to the control valve 50, the check valve 91 is closed, preventing the hydraulic oil accumulated in the control valve 50 from flowing out towards the side of the opening 16d of the rod 16. Consequently, the next time the hydraulic oil flows from the opening 16d of the rod 16 to the control valve 50, the control valve 50 can quickly control the damping force. This further improves the stability of the damping force control by the control valve 50.

[0073] In the hydraulic shock absorber 100 according to (1), the first guide path 175 preferably comprises the horizontal perforated first passage 175a, which extends from the oil inlet 173 in the direction intersecting the centerline CL of the rod 16, and the vertical perforated second passage 175b, which extends from the first passage 175a to the oil outlet 174. The second passage 175b is located on the centerline CL of the rod 16.

[0074] Therefore, the hydraulic oil discharged from the opening 16d of the rod 16 can be guided radially outside the control valve 50 through the horizontal perforated first passage 175a and then through the vertical perforated second passage 175b to the control valve 50. That is, the flow direction of the hydraulic oil discharged from the opening 16d can be easily directed in a way that does not affect the operation of the control valve 50. Therefore, the stability of the damping force control by the control valve 50 can be further improved.

[0075] The hydraulic shock absorbers 10, 100 according to the present invention are not limited to the embodiments described above, as long as the operation and effect of the present invention are demonstrated. COMMERCIAL APPLICABILITY

[0076] The hydraulic shock absorbers 10, 100 according to the present invention are suitable for mounting on a semi-trailer vehicle. Reference symbol list 10 hydraulic shock absorbers 11. Vehicle body-side pipe 11a Final section 13 axle-side pipe 13a lower end section 15 cylinders 16 bars 16a upper end section 16b Interior (internal flow path) 16c lower end section 16d opening 16f outer perimeter area 18 first oil chamber 19 second oil chamber 21 pistons 22 Reservoir 23 Damping force generating device 40 Actuator 50 Control valve 53 Valve bodies 55 Valve seat 73 Oil inlet 74 Oil outlet 75 first guided tour 76 second leadership path 77 first hole 78 second hole 79 Outer circumferential surface of the guide element 81 ring-shaped groove 82 Sealing groove 83 Sealing element 91 Check valve 100 hydraulic shock absorbers 170 guide element 173 Oil inlet 174 Oil outlet 175 first guided tour 175a first passage 175b second trial 179 external perimeter area CL center line of the pole QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 5452434B

[0003] JP 2017-180689A

[0003]

Claims

[1] Hydraulic shock absorber, comprising: a telescopic tube on the vehicle body side and a telescopic tube on the wheel side, each arranged on a vehicle body side and a wheel side; a cylinder extending from a lower end section of the wheel-side tube to an inside of the vehicle body-side tube; a reservoir located outside the cylinder and designed to store hydraulic oil; a rod extending from an upper end section of the vehicle body-side tube to an inside of the cylinder, wherein the rod is a tubular element designed to allow hydraulic oil to pass through it, and wherein the rod has an opening at an upper section designed to allow hydraulic oil to be discharged radially outwards; a piston that is provided at a lower end section of the rod and divides the inside of the cylinder into two oil chambers; a control valve provided on the upper end section of the vehicle body-side tube, including a valve body located on a centerline of the rod and displaceable along the centerline, and configured to exert flow path resistance on the hydraulic oil flowing from the rod opening to the reservoir by means of a displacement of the valve body; and a guide element located between an upper end of the rod and the control valve and on the centerline of the rod, comprising an oil inlet located radially outside an outer circumferential surface of the rod and configured to introduce hydraulic oil from the opening of the rod, an oil outlet configured to direct hydraulic oil to the control valve, and a first guide path that directs the hydraulic oil introduced from the oil inlet to the oil outlet. [2] Hydraulic shock absorber according to claim 1, wherein the guide element further comprises a second guide path that directs the hydraulic oil flowing from the control valve to the reservoir, the first guide path extends in a longitudinal direction along the rod, and The second guide path extends in a radial direction along the rod and is separate from the first guide path. [3] Hydraulic shock absorber according to claim 2, wherein the guide element includes an annular groove that extends over the entire circumference of an outer circumferential surface, and The ring-shaped groove is communicatively connected to the second guide path. [4] Hydraulic shock absorber according to claim 2, wherein the oil outlet is located radially outside the control valve. [5] Hydraulic shock absorber according to claim 1, wherein the guide element comprises a sealing element that seals between the reservoir and a receiving chamber in which the control valve is housed. [6] Hydraulic shock absorber according to claim 1, wherein at least part of the control valve is fitted into the guide element. [7] Hydraulic shock absorber according to claim 1, further comprising: a check valve designed to allow only one flow of hydraulic oil from the rod opening to the control valve. [8] Hydraulic shock absorber according to claim 1, wherein the first guide path comprises a horizontal, perforated first passage extending from the oil inlet in a direction intersecting the centerline of the rod, and a vertical, perforated second passage extending from the first passage to the oil outlet, and The second pass is located on the center line of the pole.

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