Valve and shock absorber with same

Abstract

The purpose of the present invention is to provide a control valve that suppresses vibration generated by a pilot valve from being transmitted to a main valve. A damper (100) is provided with a control valve (113). A control valve (113) is provided with: a main valve (18) for controlling the flow rate of hydraulic oil; a pilot valve (19) for opening and closing the main valve (18) by controlling the pressure of a back pressure chamber (6) disposed on the back surface side of the main valve (18); a communication passage (5) that communicates the pilot valve (19) and the back pressure chamber (6); and a resonance structure (a branch path (41), a resonance chamber (42)) that suppresses pressure vibration transmitted by the hydraulic oil in the communication path (5).

Description

Technical Field

[0001] The present invention relates to a valve composed of a main valve and a pilot valve, and a shock absorber including the valve. Background Art

[0002] For example, a shock absorber that controls damping force is described in Patent Document 1. Patent Document 1 describes a shock absorber mounted on a vehicle that actively controls the damping force to improve vehicle stability and ride comfort. This shock absorber includes a damping force modulator in its internal hydraulic circuit to control the flow of hydraulic oil and adjust the damping force. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-7918 Summary of the Invention Problems to be solved by the invention

[0004] The damping force modifier disclosed in Patent Document 1 changes the pressure upstream of the pilot valve according to the pilot valve opening. This pressure is then transmitted to the back-pressure chamber of the main valve via a communication path, thereby adjusting the main valve opening and controlling the flow rate of the hydraulic oil. Since the damping force modifier is part of the shock absorber's hydraulic circuit, it is a mechanism that adjusts the shock absorber's damping force by controlling the flow rate of the hydraulic oil.

[0005] However, in Patent Document 1, the pilot valve and the main valve are connected only by a communication path, and vibration generated by the pilot valve may be transmitted to the main valve, which may generate abnormal sound. Patent Document 1 does not consider suppressing the vibration transmitted from the pilot valve to the main valve.

[0006] An object of the present invention is to provide a valve that suppresses transmission of vibration generated by a pilot valve to a main valve, and a damper including the valve. Technical means to solve the problem

[0007] In order to achieve the above-mentioned purpose, one embodiment of the present invention provides a shock absorber, which has a control valve that adjusts the pressure of the working oil passing through and controls the damping force, and is characterized in that the control valve has: a main valve, which is used to control the flow rate of the working oil; a pilot valve, which is used to control the pressure of a back pressure chamber arranged on the back side of the main valve to open and close the main valve; a connecting path, which connects the pilot valve and the back chamber; and a resonance structure, which suppresses the pressure vibration transmitted by the working oil in the connecting path. Effects of the Invention

[0008] According to the present invention, it is possible to provide a valve that suppresses transmission of vibration generated by a pilot valve to a main valve, and a damper including the valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a cross-sectional view showing a schematic structure of a vibration damper 100 according to an embodiment of the present invention. Figure 2 It is a cross-sectional view showing a schematic structure of a general control valve 113 ′ (comparative example). Figure 3 This is a cross-sectional view showing a schematic structure of a control valve 113 according to the first embodiment of the present invention. Figure 4 yes Figure 3 The bottom view of the branch plate 43, the inlet plate 44 and the connecting plate 45 is shown. Figure 5 This is a perspective view of the pilot valve body 16 as viewed from below. Figure 6 This is a diagram showing the principle of a Helmholtz resonator. Figure 7 This is a block diagram related to vibration transmission from the pilot valve to the main valve. Figure 8 This is a diagram showing the relationship among an example of the transmission loss of the Helmholtz resonator, the vibration frequency of the pilot valve 19 , and the target frequency of the opening and closing operation of the main valve 18 . Figure 9 It is a bottom view showing a part of the component structure of the control valve 113 according to the second embodiment of the present invention. Figure 10 It is a bottom view showing a part of the component structure of the control valve 113 according to the third embodiment of the present invention. Figure 11 This is a schematic diagram showing another structural example 1 of the silencer according to the fourth embodiment of the present invention. Figure 12 This is a schematic diagram showing another structural example 2 of the silencer according to the fourth embodiment of the present invention. Figure 13 This is a schematic diagram showing another configuration example 3 of the silencer according to the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In principle, identical elements are designated by the same reference numerals throughout the drawings. Descriptions of parts having identical functions will be omitted. The configurations described below are merely examples, and the present invention is not limited to the specific embodiments described below.

[0011] In this specification, the upper direction on the paper of the drawings is defined as “upper”, and the lower direction on the paper is defined as “lower”.

[0012] use Figure 1 An example in which the valve of the present invention is applied to a shock absorber will be described. Figure 1It is a cross-sectional view showing a schematic structure of a vibration damper 100 according to an embodiment of the present invention.

[0013] The shock absorber 100 is constructed such that a rod 110 connected to a piston 111 protrudes from a portion of a housing 115 that forms the outer shell. Within the housing 115 are an inner cylinder 106 that houses the piston 111 and an outer cylinder 107 disposed on the outer periphery of the inner cylinder 106. The housing 115 is disposed on the outer periphery of the outer cylinder 107. One end (the upper side in the figure) of the outer cylinder 107 is open, while the other end (the lower side in the figure) is closed by a blocking portion 107a. The inner cylinder 106 is open at both ends, with one end (the upper side in the figure) being closed by contact with the housing 115 and the other end (the lower side in the figure) being closed by contact with the blocking portion 107a of the outer cylinder 107.

[0014] The inner space of the inner tube 106 is divided by the piston 111 to form a piston lower chamber 101 located below the piston 111 and a piston upper chamber 102 located above the piston 111 .

[0015] A piston flow path 111 a is formed in the piston 111 , which communicates between the piston lower chamber 101 and the piston upper chamber 102 . A first check valve 112 is provided in the piston flow path 111 a .

[0016] A connecting flow path 104 for storing hydraulic oil is formed between the inner cylinder 106 and the outer cylinder 107. A communication port 103 is formed in the inner cylinder 106 for connecting the piston upper chamber 102 and the connecting flow path 104.

[0017] An oil reservoir 105 is formed between the outer tube 107 and the housing 115. A blocking portion 107a of the outer tube 107 has a blocking portion flow path 107b communicating the oil reservoir 105 with the piston lower chamber 101. The blocking portion flow path 107b is provided with a second check valve 114.

[0018] Furthermore, the shock absorber 100 of the present embodiment includes a control valve 113 (valve) connected to the connecting flow path 104 and the oil reservoir 105 .

[0019] When the vehicle passes over a step and the tires descend, the rod 110 of the shock absorber 100 moves in a direction extending from the housing 115 (upward in the figure). This is called extension. During this extension, the piston 111 connected to the rod 110 also moves upward in the figure, pressurizing the hydraulic oil in the piston upper chamber 102. Consequently, the hydraulic oil is discharged through the communication port 103 into the connecting flow path 104 and directed to the control valve 113.

[0020] The opening of control valve 113 is adjusted based on an instruction from a controller (not shown). This adjusts the pressure loss caused by the hydraulic oil flowing through it, thereby adjusting the damping force acting as a shock absorber. The hydraulic oil flowing out of control valve 113 is discharged into the oil reservoir 105 and then directed to the lower piston chamber 101 through the second check valve 114. At this time, the volume increase in the lower piston chamber 101 is greater than the volume decrease in the upper piston chamber 102. However, since gas is enclosed in the oil reservoir 105, the shortfall in the hydraulic oil is compensated by the expansion of the gas.

[0021] When a car ascends a staircase, for example, and the tires rise, the rod 110 of the shock absorber 100 is pressed into the housing 115. This is called the compression-side operation. During the compression-side operation, the hydraulic oil pressure in the lower piston chamber 101 rises, causing it to flow through the first check valve 112 into the upper piston chamber 102. Since the volume reduction in the lower piston chamber 101 is greater than the volume increase in the upper piston chamber 102, the excess hydraulic oil is discharged through the communication port 103 into the connecting flow path 104 and directed to the control valve 113. Similar to the expansion-side operation described above, the pressure of the hydraulic oil passing through the control valve 113 is regulated and discharged into the reservoir chamber 105. Since the pressure in the reservoir chamber 105 is lower than that in the lower piston chamber 101, the hydraulic oil in the reservoir chamber 105 cannot pass through the second check valve 114. Therefore, the increased hydraulic oil in the reservoir chamber 105 is absorbed by the compression of the gas within the reservoir chamber 105.

[0022] use Figure 2 A general control valve 113 ′ (comparative example) will be described. Figure 2 This is a cross-sectional view showing a schematic structure of a general control valve 113' (comparative example). The present invention has characteristics in the control valve, which will be described in detail in Examples 1 to 4 described below.

[0023] A typical control valve 113' is incorporated into a portion of the hydraulic circuit used to generate the damping force of the shock absorber 100. While the shock absorber in question flows hydraulic oil during expansion and contraction, this embodiment targets shock absorbers in which the hydraulic oil flows in the same direction both on the extension and compression sides. Therefore, the control valve 113' also targets control valves in which the hydraulic oil flows in a single direction. The illustrated control valve 113' is roughly cylindrical and, except for some of its flow paths and structures, is axisymmetric. In the following description, the direction D1 along the central axis of the cylinder is referred to as the axial direction, and the direction D2 perpendicular to the axial direction D1 is referred to as the radial direction.

[0024] The mechanism by which control valve 113' generates damping force is described below. The hydraulic oil flowing into the control valve inlet 1 is split into two streams. One stream is supplied to the main upstream chamber 3 via the main inlet passage 2. The other stream passes through the inlet orifice 15a, formed by a portion of the pilot pin 15, where it is reduced in pressure and supplied to the pilot upstream chamber 4. The control valve inlet 1 and the main inlet passage 2 are connected to the connecting flow path 104.

[0025] The pilot valve 19 is composed of a pilot valve seat 16a, which is part of the pilot valve body 16, and a pilot valve core 17. The opening and closing force of the pilot valve 19 is controlled by a solenoid or spring (not shown) provided above the pilot valve core 17. The hydraulic oil passing through the pilot valve 19 is guided through the pilot downstream chamber 7 to the main downstream chamber 8, which serves as the outlet. The main downstream chamber 8 is connected to the oil reservoir 105.

[0026] When the pilot valve 19 is controlled to close, the pressure in the pilot upstream chamber 4 increases. When the pilot valve 19 is controlled to open, the pressure in the pilot upstream chamber 4 decreases. Since the pilot upstream chamber 4 (pilot valve 19) is connected to the backpressure chamber 6 via the communication passage 5, hydraulic oil is drawn in and discharged, making the pressures in the pilot upstream chamber 4 and the backpressure chamber 6 equal.

[0027] The back pressure chamber 6 is composed of a main valve element 14 formed of a rubber seal 13 and a metal disk 12, a pilot pin 15, and a pilot valve body 16. The back pressure chamber 6 is located behind the main valve 18. The pilot valve 19 controls the pressure in the back pressure chamber 6 to open and close the main valve 18.

[0028] The main valve 18 is composed of the main valve element 14, the pilot pin 15 that holds the main valve element 14, the main valve body 11, and the main valve seat 11a that is a part of the main valve body 11. The main valve 18 controls the flow rate of the hydraulic oil.

[0029] The disk 12 has an opening (through hole) 12b at its center for the pilot pin 15 to pass through. The main valve core 14 is clamped by the main valve body 11 and the pilot pin 15 via the inner peripheral side portion of the disk 12 formed with the opening (through hole 12b) and is retained on the main valve body 11. Figure 2 In the comparative example, the main valve seat 11 a is held on the main valve body 11 by being formed integrally with the main valve body 11 .

[0030] Because the pressure-receiving area of ​​the main valve element 14 on the backpressure chamber 6 side is larger than the pressure-receiving area on the main upstream chamber 3 side, when the pilot valve 19 is opened slightly, the main valve element 14 is pushed toward the main upstream chamber 3. When the pilot valve 19 is opened wider, the pressure in the pilot upstream chamber 4 decreases, and as a result, the pressure in the backpressure chamber 6 also decreases. This reduces the pushing force of the main valve element 14, causing the main valve element 14 to move toward the backpressure chamber 6, and the main valve 18 opens. With the main valve 18 opened, hydraulic oil flows from the main upstream chamber 3 to the main downstream chamber 8 through the main valve 18.

[0031] Since the opening degree of the main valve 18 can be controlled by the opening degree of the pilot valve 19 , a mechanism is formed in which the damping force of the shock absorber 100 including the control valve 113 ′ is controlled by controlling the flow resistance of the control valve 113 ′.

[0032] In the control valve 113' described above, when the main valve 18 is operated in the opening direction, the volume of the back-pressure chamber 6 decreases, and the hydraulic oil in the back-pressure chamber 6 is discharged to the pilot upstream chamber 4 through the communication passage 5. On the other hand, when the main valve 18 is operated in the closing direction, the volume of the back-pressure chamber 6 increases, and the hydraulic oil is supplied from the pilot upstream chamber 4 to the back-pressure chamber 6 through the communication passage 5.

[0033] As described above, since smooth flow of hydraulic oil through the communication passage 5 is important during the opening and closing of the main valve 18, the communication passage 5 preferably has a wide flow path cross-section. However, if the pilot valve 19 vibrates for some reason, the wider the flow path cross-section of the communication passage 5, the more easily the pressure changes are transmitted to the backpressure chamber 6 through the communication passage 5, increasing the likelihood of vibration of the main valve 18. Unexpected vibration of the main valve 18 could result in abnormal sound or damping force. The various embodiments of the present invention provide a structure that suppresses the propagation of this vibration.

[0034] Hereinafter, an embodiment of the control valve 113 to which the present invention is applied will be described. Example 1

[0035] use Figure 3 and Figure 4 The control valve 113 according to the first embodiment of the present invention will be described. Figure 3 This is a cross-sectional view showing a schematic structure of a control valve 113 according to the first embodiment of the present invention. Figure 4 yes Figure 3 The bottom view of the branch plate 43, the inlet plate 44 and the connecting plate 45 is shown. Figure 5 This is a perspective view of the pilot valve body 16 as viewed from below. Figure 5 In the figure, the pilot valve body 16 is reversed upside down and a part of the structure is omitted. Figure 2 The same components as in the comparative examples shown are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0036] The control valve 113 of this embodiment is Figure 2 The control valve 113 ′ is different in that it includes a branching plate 43 , an inlet plate 44 , a communication plate 45 , and a resonance chamber 42 (space) in the pilot valve body 16 .

[0037] like Figure 5As shown, the resonance chamber 42 includes a recess (cavity) bored upward from the bottom in the circumferential direction of the pilot valve body 16. The resonance chamber 42 has a bottom 42a and does not penetrate the pilot valve body 16 in the vertical direction.

[0038] The opening of the recess (cavity) on the backpressure chamber 6 side is blocked by the branch path plate 43. When the opening of the recess (cavity) on the backpressure chamber 6 side is closed, the branch path plate 43 has a through-hole 41b with a smaller cross-sectional area than the opening. In other words, the resonance chamber 42 (space) is formed by the recess (cavity) opening toward the backpressure chamber 6 and the branch path plate 43, which blocks the opening of the recess (cavity) and has the through-hole 41b with a smaller cross-sectional area than the recess (cavity). The through-hole 41b constitutes at least a portion of the branch path 41.

[0039] The concave portion (cavity) is a structure that is symmetrical with respect to the D1 axis. Figure 2 The control valve 113' is the same.

[0040] The open side (lower side) of the resonance chamber 42 is covered by a branch path plate 43, and the branch path 41 formed in the branch path plate 43 communicates with the resonance chamber 42. The cross-sectional area C1 of the resonance chamber 42 in a direction perpendicular to the vertical direction is larger than the cross-sectional area C2 of the portion of the branch path 41 (through hole) connected to the inlet of the resonance chamber 42 (C1>C2). Furthermore, the volume V1 of the resonance chamber 42 is larger than the volume V2 of the branch path 41 (V1>V2).

[0041] The branch plate 43, inlet plate 44, and connecting plate 45 each have openings (through holes) 43b, 44b, and 45b formed in their centers, through which the pilot pin 15 is inserted. The inner circumferences of the branch plate 43, inlet plate 44, and connecting plate 45 are sandwiched between the pilot valve body 16 and the pilot pin 15.

[0042] The branch path 41 is formed on the branch path disk 43 so as to penetrate the branch path disk 43 and extend in the radial direction. The branch path 41 is formed by being sandwiched between the inlet disk 44 and the pilot valve body 16 in the vertical direction.

[0043] The inlet disk 44 has a branch inlet through-hole 41a formed therein. The branch inlet through-hole 41a extends through the inlet disk 44 and communicates with the branch path 41 of the branch path disk 43. The branch inlet through-hole 41a forms a part of the branch path 41.

[0044] A communication path 5 is formed in the communication path plate 45. This communication path 5 penetrates the communication path plate 45, communicates with the opening (through hole) 45b, and extends radially outward from the opening (through hole) 45b. The branch path 41 formed in the branch path plate 43 communicates with the branch inlet through hole 41a on the radial inner side and communicates with the resonance chamber 42 on the radial outer side.

[0045] When the branch path disk 43 , inlet disk 44 and communication path disk 45 are stacked, the communication path 5 , the branch inlet through-hole 41 a and the branch path 41 are connected, and the resonance chamber 42 and the communication path 5 are connected via the branch inlet through-hole 41 a and the branch path 41 .

[0046] The back pressure chamber 6 is formed by the main valve element 14 , the pilot pin 15 , the pilot valve body 16 , and the communication path plate 45 .

[0047] In communication passage 5, where pressure vibrations caused by hydraulic oil (hydraulic fluid) may propagate, a resonant chamber 42 passing through branch passage 41 forms a Helmholtz resonator, thereby suppressing pressure vibrations of a specific frequency within the pressure vibrations propagating through communication passage 5. Resonant chamber 42 is a space that expands toward the side opposite to branch passage 41, which branches from communication passage 5, and connects to branch passage 41 with branch passage 41 interposed therebetween, expanding toward the side opposite to communication passage 5. In this embodiment, branch passage 41 and resonant chamber 42 form a resonant structure.

[0048] Here, the Helmholtz resonator will be briefly described. Figure 6 The principle of a Helmholtz resonator is shown.

[0049] The bottle body 63 of the bottle 62 is connected to the neck 64. Assuming that the speed of sound is v, the volume of the bottle body 63 of the bottle 62 is V0, and the cross-sectional area and length of the neck 64 are S and L respectively, the resonant frequency f of the Helmholtz resonance is H As shown in formula (1) (Source: Simple Proof of Helmholtz Resonance Mechanism and Resonance Frequency Theory Yukkuri Machine Learning (laid-back-scientist.com)).

[0050] [Formula 1]

[0051] Referring to Equation 1, the suppressed frequency can be calculated based on the cross-sectional area and length of the branch path, the volume of the resonance chamber, and the speed of sound of the hydraulic oil filling the space. Therefore, the shapes of the respective components can be determined based on the frequency of pressure propagation to be suppressed.

[0052] Furthermore, the response frequency desired for opening and closing the main valve 18 by the pilot valve 19 is approximately one order of magnitude lower than the vibration frequency of the pilot valve 19, whose transmission is desired to be suppressed. Since the Helmholtz resonator can suppress the frequency near the desired frequency, if the desired transmission frequency is approximately one order of magnitude apart, the transmission loss at that frequency can be sufficiently reduced. Consequently, the degradation of the response characteristics of the pilot valve 19 due to the installation of the Helmholtz resonator is negligible.

[0053] Figure 7This is a block diagram related to vibration transmission from the pilot valve to the main valve. Structurally, the Helmholtz resonator 60 consists of a branch path 41 branching from the communication path 5 and a resonance chamber 42. However, vibration transmission occurs when the pilot valve 19 and the main valve 18 are connected in series, sandwiching the Helmholtz resonator 60.

[0054] In the Helmholtz resonator 60, if the length of the branch path 41 is set to l b , the radius of the branch path 41 is a, the volume of the resonance chamber 42 is V, and the flow path cross-sectional area of ​​the communication path 5 is S, then the transmission loss TL at the frequency f is obtained by the following formula (2).

[0055] [Formula 2]

[0056] Among them, f r , C0 are obtained from the following equations (3) and (4) respectively. C is the speed of sound.

[0057] [Formula 3]

[0058] [Formula 4]

[0059] (Source: Ohnaka Itsuo, "Reduction of Mechanical Noise (Part 2)," Journal of the Japan Society of Marine Engines, Vol. 4, No. 4, p. 179 (1969)) Figure 8 The figure shows an example of the transmission loss of a Helmholtz resonator, the vibration frequency of the pilot valve 19, and the relationship between the target frequency of the opening and closing operation of the main valve 18. In this Helmholtz resonator 60, it can be confirmed that almost no loss occurs at the opening and closing frequency of the main valve 18, while a large loss occurs at the vibration frequency of the pilot valve 19.

[0060] In the conventional structure, priority must be given to either reducing the cross-sectional area of ​​the communication passage 5 to suppress pressure propagation or increasing the cross-sectional area of ​​the communication passage 5 to increase the opening and closing response speed of the main valve 18 .

[0061] According to the structure of this embodiment, by providing a structure constituting a Helmholtz resonator in the control valve 113, the flow path cross-sectional area of ​​the communication path 5 can be increased to improve the opening and closing response speed of the main valve 18, and the pressure vibration propagating in the communication path 5 can be suppressed. Example 2

[0062] use Figure 9 The control valve 113 according to the second embodiment of the present invention will be described. Figure 9It is a bottom view showing a part of the component structure of the control valve 113 according to the second embodiment of the present invention.

[0063] The control valve 113 of this embodiment is Figure 3 The difference between the control valve 113 and the control valve 113 is that the control valve 113 has an inlet plate 46, a branch path plate 47 and an outlet plate 48 that form the branch path 41 of the Helmholtz resonator. Figure 3 The control valve 113 is the same. In this embodiment, the branch path 41 is formed by stacking a plurality of disks (the inlet disk 46, the branch disk 47, and the outlet disk 48).

[0064] The branch path of the Helmholtz resonator in this embodiment is formed by stacking, in order from the bottom, a communication path disk 45, an inlet disk 46, a branch path disk 47, and an outlet disk 48. These disks are formed in a substantially circular shape.

[0065] The communication plate 45, inlet plate 46, branch plate 47, and outlet plate 48 each have openings (through holes) 45b, 46b, 47b, and 48b at their centers, through which the pilot pin 15 is inserted. The inner circumferences of the communication plate 45, inlet plate 46, branch plate 47, and outlet plate 48 are sandwiched between the pilot valve body 16 and the pilot pin 15.

[0066] The communication path 5 is formed in the communication path plate 45 . The communication path 5 penetrates the communication path plate 45 , communicates with the opening (through hole) 45 b , and extends radially outward from the opening (through hole) 45 b .

[0067] The inlet disk 46 has a branch inlet through-hole 41a formed therein. The branch inlet through-hole 41a penetrates the inlet disk 46 and communicates with the branch path 41 of the branch path disk 47. The branch inlet through-hole 41a constitutes a part of the branch path 41.

[0068] Branching path disk 47 is formed with a cutout portion 41n that penetrates branching path disk 47 and spirals in the circumferential direction of branching path disk 47. Furthermore, by blocking cutout portion 41n in the vertical direction with inlet disk 46 and outlet disk 48, branching path 41 is formed. In other words, inlet disk 46 and outlet disk 48 serve as the flow path wall surfaces of branching path 41.

[0069] The outlet disc 48 has a branch outlet through-hole 41 c formed therein. The branch outlet through-hole 41 c penetrates the outlet disc 48 and communicates with the branch path 41 . The branch outlet through-hole 41 c constitutes a part of the branch path 41 .

[0070] When the connecting path disk 45, the inlet disk 46, the branch path disk 47, and the outlet disk 48 are stacked, the connecting path 5, the branch inlet through-hole 41a, the branch path 41, and the branch outlet through-hole 41c are connected, and the resonance chamber 42 and the connecting path 5 are connected through the branch inlet through-hole 41a, the branch path 41, and the branch outlet through-hole 41c.

[0071] This embodiment is characterized by forming a spiral branch path 41 on a branch path disk 47. The length of this spiral branch path 41 is longer than that of the branch path 41 formed on the branch path disk 43 of Example 1. The frequency at which propagation is suppressed by the Helmholtz resonator can be adjusted by the length of the branch path. According to this embodiment, the effective length of the branch path 41 can be varied by changing the combined installation angle of the communication path disk 45 and the inlet disk 46, making it easy to achieve propagation suppression corresponding to the vibration frequency generated by the pilot valve 19.

[0072] Furthermore, by extending the branch inlet through-hole 41a in the inlet disk 46 toward the outer circumference, the branch path 41 in the branch path disk 47 can be connected to the second column from the inner circumference. By selectively using this structure, the frequency range that can be handled can be further expanded.

[0073] Furthermore, in this embodiment, outlet plate 48 is provided to connect resonant chamber 42 and branch path 41 on the outer circumference. This allows branch path 41 in branch path plate 47 to be positioned on the outer circumference, thereby extending the flow rate. However, if the target propagation suppression frequency can be achieved even by connecting branch path 41 in branch path plate 47 to the inner circumference of resonant chamber 42, outlet plate 48 is unnecessary. Therefore, in this case, outlet plate 48 is not essential.

[0074] Furthermore, to achieve the same propagation suppression frequency while increasing the flow path cross-sectional area of ​​the branch path 41, the branch path 41 needs to be lengthened. Since a larger flow path cross-sectional area makes manufacturing (processing) easier, the branch path 41 in the branch path plate 47 should be as long as possible.

[0075] In the present embodiment, the cutout portion 41 n in which the branch path plate 47 is formed is formed in a spiral shape, but the cutout portion 41 n may be formed in a curved shape, for example. Example 3

[0076] use Figure 10 The control valve 113 according to the third embodiment of the present invention will be described. Figure 10 It is a bottom view showing a part of the component structure of the control valve 113 according to the third embodiment of the present invention.

[0077] The control valve 113 of this embodiment differs from the control valve 113 of the second embodiment in that the connecting path disk 45', the inlet disk 46', the branch path disk 47', and the outlet disk 48' that constitute the branch path 41 of the Helmholtz resonator each have a keyway 52, and the pilot valve body 16 in which these are provided has a key 51. The rest of the structure is the same as the control valve 113 of the second embodiment.

[0078] The branch path of the Helmholtz resonator in this embodiment is formed by aligning and overlapping the positions of the connecting path plate 45', the inlet plate 46', the branch path plate 47', and the outlet plate 48' with the positions of their respective key grooves 52 starting from the bottom, and aligning and inserting them with the position of the key 51 of the pilot valve body 16.

[0079] According to this embodiment, the positions of the disks constituting the branch path can be accurately aligned, and the positional relationship between the disks can be suppressed from being damaged during or after assembly, so that the maximum transmission loss of the pressure vibration can be achieved and maintained at the correct frequency. Figure 9 In the embodiment, four key grooves 52 are provided on the outer periphery of each of the plurality of disks, but this number is not required and can be reduced as needed. It is sufficient to have at least one key groove 52. In addition, more key grooves 52 can be provided to further improve the adjustment accuracy.

[0080] In the present invention, the disks connecting to the branch passage 41 are preferably made of metal. However, resin materials such as rubber may be used for one or two of the disks. If the disks are not flat, there is a possibility that hydraulic oil will flow between overlapping disks. Therefore, replacing some of the disks with resin can improve the adhesion between the disks and prevent unintended leakage of hydraulic oil.

[0081] Alternatively, the depth of the counterbores in the pilot valve body 16 inserted into each disk connected to the branch passage 41 may be made shallower on the outer circumference than on the inner circumference. In this case, each disk held between the pilot valve body 16 and the pilot pin 15 is simultaneously pushed by the pilot valve body 16 on the inner circumference and lifted on the outer circumference. This generates elastic force due to the deformation of each disk, improving the tightness between the disks and suppressing leakage of hydraulic oil.

[0082] In addition, while the resonant chamber structure in the present invention is a single, axisymmetric space, it is also possible to provide walls within the space to create multiple spaces of varying volumes. In this case, the target frequency at which transmission loss occurs can be easily changed by selecting the space to connect the branch lines. Example 4

[0083] use Figures 11 to 13 Another configuration example of the muffler will be described. Figure 11 This is a schematic diagram showing another structural example 1 of the silencer according to the fourth embodiment of the present invention. Figure 12 This is a schematic diagram showing another structural example 2 of the silencer according to the fourth embodiment of the present invention. Figure 13 This is a schematic diagram showing another structural example 3 of the silencer according to the fourth embodiment of the present invention.

[0084] [Other structural examples 1] like Figure 11As shown, in the muffler 70 of Structural Example 1, two expansion parts 71 and 72 are connected by a connecting pipe 73. The expansion part 71 is connected to an inlet pipe 74 communicating with the pilot valve 19. The expansion part 72 is connected to an outlet pipe 75 communicating with the back pressure chamber 6.

[0085] The fluid (hydraulic oil) that passes through inlet pipe 74 flows into expansion section 71, which has a larger cross-sectional area than inlet pipe 74. The velocity and pressure of the fluid (hydraulic oil) that flows into expansion section 71, which can cause noise, are reduced. Only an amount of fluid (hydraulic oil) with reduced velocity and pressure passes through the cross-sectional area of ​​connecting pipe 73. The remaining fluid (hydraulic oil) reflects off the inner wall of expansion section 71, further reducing its velocity and pressure, which can cause noise.

[0086] The fluid (hydraulic oil) that passes through connecting tube 73 flows into expansion section 72, which has a larger cross-sectional area than connecting tube 73. The velocity and pressure of the fluid (hydraulic oil) that enters expansion section 72, which can cause noise, are reduced. The fluid (hydraulic oil) with reduced velocity and pressure is discharged from outlet tube 75 in an amount corresponding to the cross-sectional area of ​​outlet tube 75. The remaining fluid (hydraulic oil) reflects off the inner wall of expansion section 72, further reducing its velocity and pressure, which can cause noise. In this way, muffler 70 reduces noise generation.

[0087] [Other structural examples 2] like Figure 12 As shown, in a muffler 80 of structural example 2, an inlet pipe 82 communicating with the pilot valve 19 and an outlet pipe 83 communicating with the backpressure chamber 6 are connected to the expansion portion 81. Furthermore, the inlet pipe 82 extends into the interior of the expansion portion 81 and has a conduit portion 82a. Similarly, the outlet pipe 83 extends into the interior of the expansion portion 81 and has a conduit portion 83a.

[0088] The fluid (operating oil) that passes through inlet pipe 82 and conduit section 82a flows into expansion section 81, which has a larger cross-sectional area than conduit section 82a. The velocity and pressure of the fluid (operating oil) flowing into expansion section 81, which can cause noise, are reduced. With this reduced velocity and pressure, only an amount of fluid (operating oil) corresponding to the cross-sectional area of ​​conduit section 83a of outlet pipe 83 passes through. The remaining fluid (operating oil) reflects off the inner wall of expansion section 81, further reducing its velocity and pressure, which can cause noise. In this way, muffler 80 reduces noise generation.

[0089] [Other structural examples 3] like Figure 13As shown, in a muffler 90 of structural example 3, an inlet pipe 92 communicating with the pilot valve 19 and an outlet pipe 93 communicating with the backpressure chamber 6 are connected to the expansion portion 91. Furthermore, the interior of the expansion portion 91 is partitioned into a first expansion portion 91a and a second expansion portion 91b by a partition wall 94. A portion of the partition wall 94 is cut away, and a conduit portion 95 is provided in the cutaway portion, connecting the first expansion portion 91a and the second expansion portion 91b.

[0090] The fluid (operating oil) that has passed through inlet pipe 92 flows into first expansion section 91a, which has a larger cross-sectional area than inlet pipe 92. The velocity and pressure of the fluid (operating oil) that has flowed into first expansion section 91a, which can cause noise, are reduced. Only an amount of fluid (operating oil) with reduced velocity and pressure passes through the conduit section 95, with the remaining fluid (operating oil) reflected by the inner wall of expansion section 81 and partition wall 94, further reducing its velocity and pressure, which can cause noise.

[0091] The fluid (operating oil) that has passed through conduit section 95 flows into second expansion section 91b, which has a larger cross-sectional area than conduit section 95. The velocity and pressure of the fluid (operating oil) flowing into second expansion section 91b, which can cause noise, are reduced. The fluid (operating oil) with reduced velocity and pressure is discharged from outlet pipe 93 in an amount corresponding to the cross-sectional area of ​​outlet pipe 93. The remaining fluid (operating oil) is reflected by the inner wall of second expansion section 91b and partition wall 94, further reducing its velocity and pressure, which can cause noise. In this way, muffler 90 reduces noise generation.

[0092] Furthermore, the present invention is not limited to the above-described embodiments and includes various variations. For example, the above-described embodiments are detailed for the purpose of easily understanding the present invention and are not necessarily limited to all components. Furthermore, a portion of the components of one embodiment may be replaced with a component of another embodiment, and a component of another embodiment may be added to a component of one embodiment. Furthermore, a portion of the components of each embodiment may be added, deleted, or replaced with another component. Explanation of symbols

[0093] 1…Control valve inlet, 2…Main inlet passage, 3…Main upstream chamber, 4…Pilot upstream chamber, 5…Connecting passage, 6…Back pressure chamber, 7…Pilot downstream chamber, 8…Main downstream chamber, 11…Main valve body, 11a…Main valve seat, 12…Disc, 12b…Opening (through hole), 13…Rubber seal, 14…Main valve core, 15…Pilot pin, 15a…Inlet orifice, 16…Pilot valve body, 16a…Pilot valve seat, 17…Pilot valve core, 18…Main valve, 19…Pilot valve, 41…Branch passage, 41a…Branch inlet through-hole Hole, 41b...through hole, 41c...branch outlet through hole, 41n...cutout, 42...resonance chamber, 42a...bottom, 43...branch plate, 43b...opening (through hole), 44...inlet plate, 44b...opening (through hole), 45...connecting plate, 45'...connecting plate, 45b...opening (through hole), 46...inlet plate, 46'...inlet plate, 46b...opening (through hole), 47...branch plate, 47'...branch plate, 47b...opening (through hole), 48...outlet plate, 48' ...outlet plate, 48b...opening (through hole), 51...key, 52...keyway, 60...Helmholtz resonator, 62...bottle, 63...bottle body, 64...neck, 70...muffler, 71...expansion, 72...expansion, 73...connecting pipe, 74...inlet pipe, 75...outlet pipe, 80...muffler, 81...expansion, 82...inlet pipe, 82a...duct, 83...outlet pipe, 83a...duct, 90...muffler, 91...expansion, 91a...first expansion, 91b...second expansion, 92 …inlet pipe, 93…outlet pipe, 94…partition wall, 95…duct portion, 100…shock absorber, 101…piston lower chamber, 102…piston upper chamber, 103…communication port, 104…connecting flow path, 105…oil storage chamber, 106…inner tube, 107…outer tube, 107a…blocking portion, 107b…blocking portion flow path, 110…rod, 111…piston, 111a…piston flow path, 112…first check valve, 113…control valve, 113′…control valve, 114…second check valve, 115…housing.

Claims

1. A shock absorber having a control valve for adjusting the pressure of the hydraulic oil passing therethrough and controlling the damping force, wherein: The control valve has: A main valve for controlling the flow rate of working oil; a pilot valve for controlling the pressure of a back-pressure chamber arranged on the back side of the main valve to open and close the main valve; a connecting passage connecting the pilot valve and the back-pressure chamber; and a resonance structure for suppressing pressure vibrations transmitted by the working oil in the connecting passage.

2. The shock absorber according to claim 1, characterized in that The resonant structure includes a branch path branching from the communication path, and a space connected to the branch path and extending toward a side opposite to the communication path with the branch path interposed therebetween.

3. The shock absorber according to claim 1, characterized in that The resonance structure is a Helmholtz resonator composed of a branch path branching from the communication path and a space connected to the branch path and having a volume larger than the volume of the branch path.

4. The shock absorber according to claim 2, characterized in that The space is formed by a cavity opening toward the back pressure chamber and a member closing the opening of the cavity and having a through hole having a smaller cross-sectional area than the opening. The through hole of the member constitutes at least a portion of the branch path.

5. The shock absorber according to claim 4, characterized in that The branch passage is formed by closing a cutout portion formed in a curved shape in a substantially circular disk with another substantially circular disk serving as a flow passage wall surface.

6. The shock absorber according to claim 4, characterized in that The branch passage is formed by closing a spiral cutout portion penetrating a substantially circular disk with another substantially circular disk serving as a flow passage wall surface.

7. The shock absorber according to claim 4, characterized in that The branch route is formed by stacking a plurality of substantially circular disks, and all the disks have at least one key groove for positioning.

8. The shock absorber according to claim 4, characterized in that The materials of the plurality of disks constituting the branch path each include at least one sheet of metal and one sheet of resin.

9. The shock absorber according to claim 1, characterized in that The invention comprises an inner cylinder for accommodating a piston connected to a rod; an outer cylinder arranged on the outer periphery of the inner cylinder; a shell arranged on the outer periphery of the outer cylinder; a connecting flow path formed between the inner cylinder and the outer cylinder; and an oil storage chamber formed between the outer cylinder and the shell. The control valve is configured to connect the connection flow path and the oil storage chamber.

10. A valve comprising a main valve for controlling the flow rate of hydraulic oil, a pilot valve for opening and closing the main valve by controlling the pressure of a back pressure chamber disposed on the back side of the main valve, and a communication path connecting the pilot valve and the back pressure chamber, wherein: A resonance structure is provided to suppress pressure vibrations transmitted by the hydraulic oil in the communication passage.

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