Decay force generating mechanism and pressure buffer device

Abstract

The damping force generating mechanism is a damping force generating mechanism having a flow path inside which a fluid flows, and includes: a valve element portion having an elastic portion that can be elastically deformed and a pressure receiving portion that receives the pressure of the fluid; a valve seat portion provided around the flow port of the flow path and capable of contacting the pressure receiving portion; and a support portion provided on a component portion that forms at least a part of the back pressure chamber and supporting the outer edge portion of the elastic portion, the back pressure chamber applying a back pressure toward the valve seat portion to the valve element portion.

Description

Technical Field

[0001] The present invention relates to a damping force generating mechanism and a pressure buffer device. Background Art

[0002] In a pressure buffer device clamped between a vehicle body and an axle of a vehicle, or in a damping force generating mechanism used for a pressure buffer device, there is a device in which the generated damping force is configured to be variable. Such a pressure buffer device and damping force generating mechanism are configured to include, for example: a back pressure chamber, a pilot valve, and an electromagnet that adjusts the opening pressure of the pilot valve. Then, pressure is introduced into the back pressure chamber, and this pressure is used to apply a force to the valve element in a direction to close the flow path to the valve element. That is, by controlling the pressure, the opening pressure of the valve element is adjusted. Further, if the opening pressure of the pilot valve is adjusted by the electromagnet, the resistance applied by the valve element to the flow of the fluid passing through the flow path can be made variable, and a desired damping force can be generated.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-281584 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] For example, in Patent Document 1, the force in the direction of closing the valve element is mainly the pressure in the back pressure chamber formed by the spool valve. However, the spool valve is always acted in a direction approaching the valve element by a leaf spring. Therefore, this spring force becomes a force that hinders the separation from the valve seat.

[0008] Here, for example, in the damping force variable valve described in Patent Document 1, the axial position on the inner peripheral side of the leaf spring as a fixed end is determined by the axial dimensions of a plurality of components such as a valve seat member, a sub-valve element, a spool valve holding member, and a spool valve. And the dimensional tolerances of these multiple components accumulate, and the axial position of the leaf spring may deviate. In such a case, the preload of the leaf spring applied to the spool valve may deviate, and the force that hinders the separation from the valve seat based on the spring force may also deviate, and individual differences may occur in mass-produced products.

[0009] An object of the present invention is to provide a damping force generating mechanism and the like that reduce the deviation of the damping force due to individual differences.

[0010] Means for Solving the Problems

[0011] For this purpose, the present invention provides a damping force generating mechanism which has a flow path inside for fluid flow. The damping force generating mechanism includes: a spool portion having an elastic portion capable of elastic deformation and a pressure-receiving portion for receiving the pressure of the fluid; a valve seat portion provided around the flow port of the flow path and capable of contacting the pressure-receiving portion; and a support portion provided on a component portion constituting at least a part of the back pressure chamber for supporting the outer edge portion of the elastic portion. The back pressure chamber applies a back pressure to the spool portion toward the valve seat portion.

[0012] Advantages of the Invention

[0013] According to the present invention, it is possible to provide a damping force generating mechanism and the like that reduce the deviation of the damping force due to individual differences. Description of the Drawings

[0014] Figure 1 is an overall view of the hydraulic shock absorber according to the first embodiment.

[0015] Figure 2 is a cross-sectional view of the outer damping portion according to the first embodiment.

[0016] Figure 3 is a perspective view of the outer damping portion according to the first embodiment, which is a partial cross-sectional view.

[0017] Figure 4 is an operation explanatory view of the hydraulic shock absorber 1 according to the first embodiment.

[0018] Figure 5 is an explanatory view of the oil flow in the outer damping portion according to the first embodiment.

[0019] Figure 6 is a perspective view of the outer damping portion according to the second embodiment, which is a partial cross-sectional view.

[0020] Figure 7 is an explanatory view of the orifice plate and the pilot valve according to the second embodiment.

[0021] Figure 8 is a perspective view of the outer damping portion according to the third embodiment, which is a partial cross-sectional view.

[0022] Figure 9 is an overall view of the hydraulic shock absorber according to the fourth embodiment.

[0023] Figure 10 is a cross-sectional view of the piston portion according to the fourth embodiment. Detailed Description of the Embodiments

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0025] <First Embodiment>

[0026] [Structure and Function of Hydraulic Buffer Device 1]

[0027] Figure 1 This is an overall view of the hydraulic buffer device 1 of the first embodiment.

[0028] As Figure 1 shown, for example, the hydraulic buffer device 1 (an example of a pressure buffer device) clamped between the vehicle body and the axle has: a cylinder part 10 that houses oil (an example of a fluid); and a rod 20, one side of which is slidably inserted into the cylinder part 10 and the other side of which is protrudingly provided from the cylinder part 10. In addition, the hydraulic buffer device 1 has: a piston part 30 provided at one end of the rod 20; and a bottom part 40 provided at one end of the cylinder part 10. And the hydraulic buffer device 1 has an outer damping part 100 that is provided outside the cylinder part 10 and generates a damping force.

[0029] In addition, in the description of this embodiment, the Figure 1 length direction of the cylinder part 10 shown is referred to as the "axial direction". In addition, the lower side of the cylinder part 10 in the axial direction is referred to as "one side", and the upper side of the cylinder part 10 is referred to as "the other side".

[0030] In addition, the Figure 1 left - right direction of the cylinder part 10 shown is referred to as the "radial direction". And in the radial direction, the central axis side is referred to as the "radial direction inner side", and the side away from the central axis is referred to as the "radial direction outer side".

[0031] [Structure and Function of Cylinder Part 10]

[0032] As Figure 1 shown, the cylinder part 10 has: a cylinder 11 that houses oil; an outer cylinder 12 provided on the outer side in the radial direction of the cylinder 11; and a damper housing 13 provided on the outer side in the radial direction of the cylinder 11 and on the outer side in the radial direction of the outer cylinder 12.

[0033] The cylinder 11 is formed in a cylindrical shape and has a cylinder opening 11H on the other side.

[0034] The outer cylinder 12 is formed in a cylindrical shape. And a communication path L is formed between the outer cylinder 12 and the cylinder 11. In addition, the outer cylinder 12 has an outer cylinder opening part 12H and an outer connection part 12J at the opposing position facing the outer damping part 100. The outer connection part 12J has a flow path for oil and protrudes toward the outer side in the radial direction, forming a connection part connected to the outer damping part 100.

[0035] The damper housing 13 is formed in a cylindrical shape. Moreover, a storage chamber R for accumulating oil supply is formed between the damper housing 13 and the outer cylinder 12. As the rod 20 relatively moves with respect to the cylinder 11, the storage chamber R absorbs the oil in the cylinder 11 or supplies oil to the cylinder 11. In addition, the storage chamber R accumulates the oil flowing out from the outer attenuation portion 100. Further, the damper housing 13 has a housing opening 13H at the opposing position opposed to the outer attenuation portion 100.

[0036] [Structure and function of the rod 20]

[0037] The rod 20 is a rod-shaped member extending relatively long in the axial direction. The rod 20 is connected to the piston portion 30 on one side. In addition, the rod 20 is connected to, for example, a vehicle body via a connecting member (not shown) or the like on the other side. The rod 20 can be either a hollow shape with a cavity inside or a solid shape without a cavity inside.

[0038] [Structure and function of the piston portion 30]

[0039] The piston portion 30 includes: a piston body 31 having a plurality of piston oil ports 311; a piston valve 32 for opening and closing the other side of the piston oil ports 311; and a spring 33 provided between the piston valve 32 and one end portion of the rod 20. And the piston portion 30 divides the oil in the cylinder 11 into a first oil chamber Y1 and a second oil chamber Y2.

[0040] [Structure and function of the bottom portion 40]

[0041] The bottom portion 40 includes: a valve seat 41, a check valve portion 43 provided on the other side of the valve seat 41, and a fixing member 44 provided along the axial direction. And the bottom portion 40 divides the first oil chamber Y1 and the storage chamber R.

[0042] [Structure and function of the outer attenuation portion 100]

[0043] Figure 2 It is a cross-sectional view of the outer attenuation portion 100 of the first embodiment.

[0044] Figure 3 It is a perspective view of the outer attenuation portion 100 of the first embodiment, which is a partial cross-sectional view.

[0045] In the following description, Figure 2 the longitudinal direction of the outer attenuation portion 100 shown (i.e., the crossing direction (for example, a substantially orthogonal direction) crossing the axial direction of the cylinder portion 10 (refer to Figure 1 )) is referred to as the "second axial direction". In addition, in the second axial direction, the left side of the outer attenuation portion 100 is referred to as the "second axis inner side", and the right side of the outer attenuation portion 100 is referred to as the "second axis outer side".

[0046] In addition,Figure 2 The vertical direction (i.e., the direction crossing the second axis) of the outer attenuation portion 100 shown is referred to as the "second radial direction". And in the second radial direction, the side along the central axis of the second axis is referred to as the "inner side of the second radial direction", and the side away from the central axis along the second axis is referred to as the "outer side of the second radial direction".

[0047] As Figure 2 shown, the outer attenuation portion 100 (an example of a damping force generating mechanism) includes: a main valve portion 50 that controls the flow of oil; a first housing 60 that houses at least the main valve portion 50; and a second housing 70 that is disposed on the opposite side of the first housing 60 in the second axial direction. And the outer attenuation portion 100 includes: a gasket 80 that is disposed between the first housing 60 and the second housing 70; an orifice plate 85 that is disposed within the first housing 60; and an adjustment portion 90 that adjusts the oil pressure in a back pressure chamber 100P described later. And the outer attenuation portion 100 includes: a connecting flow path portion 110 that forms a flow path for oil from a communication path L with respect to the main valve portion 50; and an outer housing 120 that houses various components constituting the outer attenuation portion 100.

[0048] (Main valve portion 50)

[0049] The main valve portion 50 has a main valve 51 that mainly generates a damping force in the outer attenuation portion 100.

[0050] The main valve 51 is generally circular in shape and is formed as a relatively thin plate. That is, the main valve 51 is formed in a generally disc shape. Additionally, the material of the main valve 51 can be, for example, a metal such as iron. And the main valve 51 is configured to be elastically deformable.

[0051] And, as Figure 3 shown, the main valve 51 is supported by the first housing 60 and the second housing 70 at the outer edge portion in the outer side of the second radial direction.

[0052] In addition, the main valve 51 is arranged to be able to contact a valve seat portion 73 of the second housing 70 described later. The main valve 51 bears the pressure of the oil in a main flow path 71 described later on the inner side of the second radial direction flowing into the valve seat portion 73. And the main valve 51 controls the flow rate of the oil flowing in the main flow path 71 by opening and closing the valve seat portion 73. Thereby, the main valve 51 generates a differential pressure and generates the damping force of the hydraulic buffer device 1.

[0053] In this way, in the main valve portion 50 (an example of a spool portion) of the first embodiment, the main valve 51 functions as an example of an elastic portion and an example of a pressure receiving portion. That is, the elastic portion and the pressure receiving portion of the main valve 51 of the main valve portion 50 in the first embodiment are configured as one body.

[0054] In addition, the main valve 51 has a hole portion 511 for oil supply flow on the inner side in the second radial direction. The flow path cross-sectional area of the hole portion 511 is formed to be sufficiently small compared to the main flow path 71 described later, for example. Also, even when the main valve 51 is in contact with the valve seat portion 73 and closes the main flow path 71, the hole portion 511 enables the flow of oil from the main flow path 71 to the back pressure chamber 100P described later.

[0055] (First housing 60)

[0056] As Figure 2 shown, the first housing 60 is mainly disposed on the outer side in the second axial direction with respect to the main valve 51. The first housing 60 can house components such as the main valve 51 inside, and the first housing 60 is formed in a cylindrical shape.

[0057] The first housing 60 has: an opening portion 61 provided on the outer side of the second axis; a housing portion 63 that houses the adjustment valve 91 of the adjustment portion 90 described later; a holding portion 65 that holds the orifice plate 85; and an opposing portion 67 that opposes the second housing 70.

[0058] The opening portion 61 has an inner diameter larger than the small diameter portion 91A of the adjustment valve 91 of the adjustment portion 90 described later. Also, a gap through which oil can flow is formed between the opening portion 61 and the small diameter portion 91A described later.

[0059] As Figure 3 shown, the housing portion 63 houses the adjustment valve 91 of the adjustment portion 90 and the compression coil spring 97 inside. In addition, the housing portion 63 forms an inflow chamber 631 into which the oil flowing in the hole flow path 851 of the orifice plate 85 flows. Also, the housing portion 63 has an outflow path 6, which causes the oil flowing into the inflow chamber 631 to flow out from the gap between the opening portion 61 and the adjustment valve 91 to the housing inner flow path 121 described later.

[0060] The outflow path 632 is formed along the second radial direction. Also, in the first housing 60 of the first embodiment, a plurality of outflow paths 632 are provided. In addition, the outflow path 632 can also be configured to function as a hole when the electromagnetic portion 95 is in a non-energized state and is pushed back by the compression coil spring 97 to the outer side in the second axis. In the case of such a configuration, the outflow path 632 functions as a safety hole for maintaining the pressure in the back pressure chamber 100P described later at a certain relatively high level.

[0061] The holding portion 65 holds the orifice plate 85. Also, the holding portion 65 constitutes a part of the back pressure chamber 100P that applies a back pressure to the main valve 51 toward the valve seat portion 73 described later.

[0062] The back pressure chamber 100P is a chamber into which the oil supply flows in through a hole portion 511 of the main valve 51 described later. In addition, the oil in the back pressure chamber 100P can flow out through the hole flow path 851 of the orifice plate 85. And the back pressure chamber 100P applies back pressure to the main valve 51 according to the oil pressure inside.

[0063] In addition, in the outer attenuation portion 100 of the first embodiment, the back pressure chamber 100P is formed by the surface on the inner side in the second radial direction of the holding portion 65 of the first housing 60, the surface on the inner side in the second axis of the orifice plate 85, and the surface on the outer side in the second axis of the main valve 51.

[0064] The opposing portion 67 has: a first connection portion 671 that is connected to the second housing 70; a first gasket contact portion 672 that contacts the surface of the gasket 80 facing the outer side in the second axis; and a first valve contact portion 673 that contacts the surface of the main valve 51 facing the outer side in the second axis.

[0065] The first connection portion 671 forms a portion that holds the first housing 60 with respect to the second housing 70. The first housing 60 (an example of the first accommodating portion) of the first embodiment is configured to be separable from the second housing 70 (an example of the second accommodating portion) in the second axial direction. And the first connection portion 671 holds and fixes the second housing 70 in such a manner that the second housing 70 does not move in the second axial direction with respect to the first housing 60. For example, this fixing method can be screw fastening or press-fitting.

[0066] The first gasket contact portion 672 is an annular surface facing the inner side in the second axis. The first gasket contact portion 672 faces the surface of the gasket 80 facing the outer side in the second axis. And the first gasket contact portion 672 contacts the surface of the gasket 80 facing the outer side in the second axis.

[0067] The first valve contact portion 673 is an annular surface facing the inner side in the second axis. The first valve contact portion 673 faces the end portion on the outer side in the second radial direction of the main valve 51. And the first valve contact portion 673 supports the outer edge portion of the main valve 51. The first valve contact portion 673 can press the main valve 51 against a valve seat portion 73 of the second housing 70 described later. In addition, in the valve opening state where the main valve 51 opens the main flow path 71, the first valve contact portion 673 functions as a fulcrum for the deformation of the main valve 51.

[0068] As described above, regarding the first housing 60 (an example of the constituent portion) of the first embodiment, its holding portion 65 constitutes at least a part of the back pressure chamber 100P that applies back pressure to the main valve 51 (an example of the valve core portion) toward the valve seat portion 73. And the first housing 60 contacts the outer edge portion of the surface of the main valve 51 facing the outer side in the second axis at the first valve contact portion 673.

[0069] Thus, in the outer attenuation portion 100 of the first embodiment, the first housing 60 that forms at least a part of the back pressure chamber 100P supports the outer edge portion of the main valve 51.

[0070] (Second housing 70)

[0071] The second housing 70 is mainly disposed on the second axial inner side with respect to the main valve 51. The second housing 70 can accommodate components such as the main valve 51 together with the first housing 60.

[0072] As Figure 3 shown, the second housing 70 has: a main flow path 71 through which oil flows; and a valve seat portion 73 provided at an end portion on the second axis outer side of the main flow path 71. In addition, the second housing 70 has: a second gasket contact portion 74 that contacts the surface of the gasket 80 facing the second axis inner side; and a second valve contact portion 75 (an example of a contact portion) that contacts the surface of the main valve 51 facing the second axis inner side. And, the second housing 70 has: a second connection portion 76 that connects to the first housing 60; a groove portion 77 that faces the outer edge portion of the surface of the main valve 51 facing the second axis inner side; and an outer flow path 79 provided on the second radius direction outer side of the main flow path 71.

[0073] Therefore, with respect to the gasket 80 of the first embodiment, by bringing its second axis outer side into contact with the first gasket contact portion 672 and bringing its second axis inner side into contact with the second gasket contact portion 74, the gasket 80 of the first embodiment is supported. In addition, with respect to the main valve 51 of the first embodiment, by bringing its second axis outer side into contact with the first valve contact portion 673 and bringing its second axis inner side into contact with the second valve contact portion 75, the main valve 51 of the first embodiment is supported.

[0074] In addition, in the present application, "support" means staying within a specified range, and sometimes refers to both the case where the object to be "supported" is "fixed" and the case where it "can move".

[0075] In addition, the second housing 70 also functions as an example of a flow path forming portion.

[0076] The main flow path 71 is formed along the second axis in the second radius direction inner side of the second housing 70. The main flow path 71 communicates with an inner flow path 111 (described later) of the connection flow path portion 110 on the second axis inner side. In addition, the main flow path 71 faces the surface of the main valve 51 facing the second axis inner side on the second axis outer side.

[0077] The valve seat portion 73 is provided at the end portion outside the second axis of the main flow path 71. The valve seat portion 73 is formed by an annular surface facing the outside of the second axis. That is, the valve seat portion 73 is integrally formed in the second housing 70. In addition, in the first embodiment, the protruding height of the valve seat portion 73 is formed to be substantially the same as that of the second valve contact portion 75. And the valve seat portion 73 forms a portion that contacts the main valve 51. That is, the main valve 51 (an example of the elastic portion) is also supported by the valve seat portion 73.

[0078] In the outer attenuation portion 100 of the first embodiment, the main valve 51 contacts the entire circumferential range of the valve seat portion 73, whereby the main valve 51 becomes a closed valve state in which the main flow path 71 is closed. In addition, in the outer attenuation portion 100 of the first embodiment, by separating the main valve 51 from the valve seat portion 73, the main valve 51 becomes an open valve state in which the main flow path 71 is opened.

[0079] The second gasket contact portion 74 is an annular surface facing the outside of the second axis. The second gasket contact portion 74 faces the surface of the gasket 80 facing the inside of the second axis. And the second gasket contact portion 74 contacts the surface of the gasket 80 facing the inside of the second axis.

[0080] The second valve contact portion 75 is an annular surface facing the outside of the second axis. The second valve contact portion 75 is provided at a position radially outside the second radius of the valve seat portion 73. In addition, the second valve contact portion 75 is provided at a position radially inside the second radius of the first valve contact portion 673 of the first housing 60. The second valve contact portion 75 contacts the end portion on the radially outside of the second radius of the main valve 51 (an example of the elastic portion).

[0081] The end portion on the outside of the second axis of the second valve contact portion 75 can be located at substantially the same height position in the second axial direction as the end portion on the outside of the second axis of the valve seat portion 73. In addition, the end portion on the outside of the second axis of the second valve contact portion 75 may be located at a position on the inside of the second axis in the second axial direction with respect to the end portion on the outside of the second axis of the valve seat portion 73.

[0082] In addition, the second valve contact portion 75 is not an essential structure, but is preferably provided, for example, from the viewpoint of preventing excessive deflection of the main valve 51.

[0083] The groove portion 77 (an example of a concave portion) is an annular groove recessed toward the inside of the second axis. The groove portion 77 is provided at a position radially outside the second valve contact portion 75 (an example of a contact portion) with respect to the main valve 51 (an example of the elastic portion). And the groove portion 77 faces the outer edge portion of the surface of the main valve 51 facing the inside of the second axis. In addition, in the first embodiment, the groove portion 77 is provided in the second axial direction at a position opposed to the first valve contact portion 673 with the main valve 51 interposed therebetween. And the groove portion 77 forms a region for enabling the end portion of the main valve 51 to be displaced toward the inside of the second axis in the open valve state in which the main valve 51 opens the main flow path 71.

[0084] The outer flow path 79 is formed along the second axis to form a flow path for the supply oil to flow. A plurality of outer flow paths 79 are provided in the first embodiment. Further, the outer flow path 79 forms a path for the oil flowing out from the main flow path 71 by opening the main valve 51 to flow into the inner flow path 121 of the housing described later.

[0085] (Gasket 80)

[0086] The gasket 80 is an annular member that is open at the inner side in the second radial direction. The thickness of the gasket 80 in the first embodiment is substantially the same as that of the main valve 51. The gasket 80 has a gap with the main valve 51, and the gasket 80 is disposed at a position on the outer side in the second radial direction with respect to the main valve 51.

[0087] Further, the gasket 80 restricts the movement of the main valve 51 in the second radial direction.

[0088] In addition, the gasket 80 (an example of the setting portion) is disposed so as to be sandwiched between the first housing 60 and the second housing 70 in the second axial direction. Further, the gasket 80 can also determine the interval in the second axial direction between the first valve contact portion 673 and the second valve contact portion 75 or the valve seat portion 73, that is, the movement range of the main valve 51 in the second axial direction, by virtue of its thickness.

[0089] The gasket 80 determines the state of the support of the main valve 51 by the first housing 60 and the second housing 70.

[0090] Further, the gasket 80 can easily change the support manner of the main valve 51 by the first housing 60 and the second housing 70, for example, by only changing the thickness which is the design of the gasket 80.

[0091] (Orifice plate 85)

[0092] The orifice plate 85 is formed in a substantially circular shape and plate shape. Further, the orifice plate 85 is press-fitted into the inside of the first housing 60 and held by the holding portion 65.

[0093] The orifice plate 85 has an orifice flow path 851 for the supply oil to flow and a circular portion 852 provided at the end portion on the outer side of the second axis of the orifice flow path 851.

[0094] The orifice flow path 851 is provided along the second axis on the inner side in the second radial direction of the orifice plate 85. In addition, the orifice flow path 851 penetrates the orifice plate 85. The flow cross-sectional area of the orifice flow path 851 is formed to be smaller than the orifice portion 511 of the main valve 51, for example. Further, the orifice flow path 851 communicates with the back pressure chamber 100P on the inner side of the second axis and communicates with the inflow chamber 631 on the outer side of the second axis.

[0095] The circular portion 852 is formed outside the second axis of the hole flow path 851 so as to surround the periphery of the hole flow path 851. Further, the circular portion 852 is formed to protrude toward the outside of the second axis with a predetermined height on the orifice plate 85. And the circular portion 852 forms a contact portion that contacts an adjustment valve 91 (described later) of the adjustment portion 90.

[0096] (Adjustment portion 90)

[0097] As Figure 2 shown, the adjustment portion 90 has: an adjustment valve 91 that controls the flow of oil in the hole flow path 851 (refer to Figure 3 ) of the orifice plate 85; a plunger 93 that is connected to the adjustment valve 91; and an electromagnet portion 95 that drives the plunger 93. Further, the adjustment valve 91 has a connection portion connected to the plunger 93 and has a small-diameter portion 91A having a diameter smaller than other portions of the adjustment valve 91. Further, the adjustment portion 90 has: a compression coil spring 97 that is disposed between the orifice plate 85 and the adjustment valve 91; and a housing portion 99 that houses the respective components constituting the adjustment portion 90.

[0098] As Figure 3 shown, the adjustment valve 91 is disposed at a position facing the circular portion 852 of the orifice plate 85 in the second axial direction. Further, the adjustment valve 91 is movable in the second axial direction. And the adjustment valve 91 can contact the circular portion 852 of the orifice plate 85 by moving toward the inside of the second axis. Thus, the adjustment valve 91 can take any state between the state of contacting the circular portion 852 and the state of being farthest away from the circular portion 852. Thereby, the adjustment valve 91 can adjust the flow rate of the oil flowing in the hole flow path 851 of the orifice plate 85.

[0099] As Figure 2 shown, the plunger 93 is a rod-shaped member formed along the second axial direction. Further, the plunger 93 functions as a movable iron core. The plunger 93 holds the adjustment valve 91 inside the second axis. When the electromagnet portion 95 is in an energized state, the plunger 93 and the adjustment valve 91 are pushed toward the inside of the second axis by the electromagnet portion 95. On the other hand, when the electromagnet portion 95 is in a non-energized state, the plunger 93 and the adjustment valve 91 are pushed back toward the outside of the second axis by the compression coil spring 97.

[0100] The electromagnet portion 95 has a coil and a fixed iron core. And by making the electromagnet portion 95 in an energized state, the plunger 93 is pushed toward the inside of the second axis.

[0101] The compression coil spring 97 contacts the orifice plate 85 inside the second axis and contacts the adjustment valve 91 outside the second axis. And the compression coil spring 97 applies a force in the direction of separating the adjustment valve 91 from the orifice plate 85 to the adjustment valve 91.

[0102] The housing portion 99 houses the plunger 93 and the electromagnet portion 95 inside. In addition, the housing portion 99 is screwed and fastened to the outer housing 120.

[0103] (Connection flow path portion 110)

[0104] As Figure 2 shown, the connection flow path portion 110 has an inner flow path 111 provided on the inner side in the second radial direction and an outer flow path 112 provided on the outer side in the second radial direction.

[0105] The inner flow path 111 communicates with the outer cylinder opening 12H inside the second axis and communicates with the main flow path 71 of the second housing 70 outside the second axis.

[0106] A plurality of outer flow paths 112 are provided. And the outer flow path 112 communicates with the housing opening 13H inside the second axis and communicates with the inner housing flow path 121 (to be described later) outside the second axis.

[0107] (Outer housing 120)

[0108] Figure 2 The outer housing 120 shown is a member having a substantially cylindrical shape. The outer housing 120 is fixed to the damper housing 13 inside the second axis by welding or the like, for example.

[0109] In addition, the outer housing 120 forms an inner housing flow path 121 as a flow path for oil inside the outer housing 120 on the outer side in the second radial direction of the second housing 70.

[0110] [Operation of the hydraulic shock absorber 1]

[0111] Next, the operation of the hydraulic shock absorber 1 configured as described above will be specifically described.

[0112] Figure 4 is an operation explanatory diagram of the hydraulic shock absorber 1 of the first embodiment.

[0113] In addition, Figure 4 (A) of shows the flow of oil during the extension stroke, Figure 4 (B) of shows the flow of oil during the compression stroke.

[0114] First, the operation of the hydraulic shock absorber 1 during the extension stroke will be described.

[0115] As Figure 4 (A) of shows, during the extension stroke, the rod 20 moves to the other side with respect to the cylinder 11. At this time, the piston valve 32 remains in a state of blocking the piston oil port 311. In addition, due to the movement of the piston portion 30 to the other side, the volume of the second oil chamber Y2 decreases. And the oil in the second oil chamber Y2 flows out from the cylinder opening 11H to the communication path L.

[0116] Moreover, oil flows into the outer damping portion 100 through the communication path L and the outer cylinder body opening 12H. In the outer damping portion 100, the oil first flows into the inner flow path 111 of the connecting flow path portion 110. Thereafter, in the outer damping portion 100, a damping force is generated in the main valve 51. In addition, the flow of the oil at this time will be described in detail later.

[0117] Thereafter, the oil flowing to the main valve 51 flows out into the housing inner flow path 121. And the oil flows into the storage chamber R from the housing opening 13H through the outer flow path 112 of the connecting flow path portion 110.

[0118] In addition, the pressure of the first oil chamber Y1 becomes relatively lower than that of the storage chamber R. Therefore, the oil in the storage chamber R flows into the first oil chamber Y1 through the bottom portion 40.

[0119] Next, the operation of the hydraulic shock absorber 1 during the compression stroke will be described.

[0120] As Figure 4 shown in (B) of, during the compression stroke, the rod 20 moves relatively to one side with respect to the cylinder 11. In the piston portion 30, the piston valve 32 that blocks the piston oil port 311 is opened by the differential pressure between the first oil chamber Y1 and the second oil chamber Y2. And the oil in the first oil chamber Y1 flows out into the second oil chamber Y2 through the piston oil port 311. Here, the rod 20 is disposed in the second oil chamber Y2. Therefore, the oil flowing from the first oil chamber Y1 into the second oil chamber Y2 is in excess by the volume of the rod 20. Accordingly, an amount of oil corresponding to the volume of the rod 20 flows out from the cylinder opening 11H into the communication path L.

[0121] And the oil flows into the outer damping portion 100 through the communication path L and the outer cylinder body opening 12H. In addition, the flow of the oil in the outer damping portion 100 is the same as the flow of the oil during the above-described extension stroke. That is, in the hydraulic shock absorber 1 of the first embodiment, during both the compression stroke and the extension stroke, the direction of the oil flow in the outer damping portion 100 is the same.

[0122] As described above, in the hydraulic shock absorber 1 of the first embodiment, a damping force is generated in the outer damping portion 100 during both the compression stroke and the extension stroke.

[0123] Next, the flow of the oil in the outer damping portion 100 of the first embodiment will be described in detail.

[0124] Figure is an explanatory view of the oil flow in the outer damping portion 100 of the first embodiment.

[0125] In addition, ​(A) is an explanatory diagram of the outer damper portion 100 when the damping force generated in the main valve 51 is adjusted to be relatively low by the adjustment portion 90. In addition, ​ (B) is an explanatory diagram of the outer damper portion 100 when the damping force generated in the main valve 51 is adjusted to be relatively high by the adjustment portion 90.

[0126] First, the operation of the adjustment portion 90 that adjusts the pressure of the oil in the back pressure chamber 100P will be described. In the first embodiment, the distance of the adjustment valve 91 from the orifice plate 85 varies according to the amount of electric current flowing through the electromagnet portion 95 (refer to ​ ). In addition, the control of the amount of electric current flowing through the electromagnet portion 95 is performed, for example, according to an ECU (Electronic Control Unit) that performs various controls in the vehicle. In the adjustment portion 90, the more electric current flows through the electromagnet portion 95, the closer the adjustment valve 91 is to the circular portion 852 of the orifice plate 85. On the other hand, the less electric current flows through the electromagnet portion 95 in the adjustment portion 90, the farther the adjustment valve 91 is from the circular portion 852 of the orifice plate 85.

[0127] And, for example, the ECU makes the amount of electric current of the electromagnet portion 95 of the adjustment portion 90 relatively small. In addition, in this example, the amount of electric current flowing through the electromagnet portion 95 is made zero. Thus, as ​ (A) shows, the adjustment valve 91 is located at a relatively far position from the circular portion 852. Thus, the oil in the back pressure chamber 100P easily flows out from the hole flow path 851 of the orifice plate 85 to the inflow chamber 631. In this case, the pressure of the oil in the back pressure chamber 100P becomes relatively low.

[0128] On the other hand, for example, the ECU makes the amount of electric current of the electromagnet portion 95 of the adjustment portion 90 relatively large. Thus, as ​ (B) shows, the adjustment valve 91 is located near the circular portion 852. Thus, the oil in the back pressure chamber 100P hardly flows out from the hole flow path 851 of the orifice plate 85 to the inflow chamber 631. In this case, the pressure of the oil in the back pressure chamber 100P becomes relatively high.

[0129] And, the adjustment portion 90 of the first embodiment can arbitrarily adjust the interval between the circular portion 852 of the orifice plate 85 and the adjustment valve 91 within a predetermined range according to the amount of electric current flowing through the electromagnet portion 95. And, the adjustment portion 90 can adjust the oil in the back pressure chamber 100P to a specified pressure according to the amount of electric current flowing through the electromagnet portion 95.

[0130] Next, the oil flow that opens the main valve 51 will be specifically described.

[0131] As ​ (A) shows, by the piston portion 30 (refer to ​)It moves axially, and the oil flowing in the inner flow path 111 flows into the main flow path 71.

[0132] Moreover, the oil flowing into the main flow path 71 flows into the back pressure chamber 100P from the hole portion 511.

[0133] In ​ In the example shown in (A) of, the oil in the back pressure chamber 100P easily flows out from the hole flow path 851 of the orifice plate 85 into the inflow chamber 631. Therefore, the pressure of the oil in the back pressure chamber 100P becomes relatively low.

[0134] Here, as described above, the adjustment portion 90 determines the pressure of the back pressure chamber 100P. And when the fluid pressure in the opening direction exceeding the force in the direction of closing the valve seat portion 73 of the main valve 51 is applied to the main valve 51 of the main valve portion 50, the main valve 51 is lifted from the valve seat portion 73, and the main flow path 71 is opened. At this time, the pressure of the back pressure chamber 100P determines the gap between the main valve 51 and the valve seat portion 73, that is, the flow path cross-sectional area. That is, the pressure of the back pressure chamber 100P determines the flow rate, that is, the damping force.

[0135] And, as ​ shown in (A) of, the oil flowing into the main flow path 71 flows in the gap between the valve seat portion 73 and the main valve 51 while the main valve 51 is deformed so as to be separated from the valve seat portion 73. In this case, in the main valve 51, the outer edge portion of the main valve 51 is displaced toward the inner side of the second axis with the first valve contact portion 673 of the first housing 60 as a fulcrum. Here, the second housing 70 of the first embodiment has a groove portion 77 that is recessed toward the inner side of the second axis and can avoid the displacement of the outer edge portion of the main valve 51. Thus, the main valve 51 can be deformed without the displacement of the outer edge portion being restricted.

[0136] Moreover, in the outer damping portion 100 of the first embodiment, the damping force is generated due to the differential pressure, and this differential pressure is generated by throttling the oil flow rate through the gap between the main valve 51 and the valve seat portion 73 of the second housing 70.

[0137] After that, the oil flowing out of the main flow path 71 by opening the main valve 51 flows in the order of the outer flow path 79, the inner flow path 121 in the housing, and the outer flow path 112, and flows out to the storage chamber R.

[0138] On the other hand, as ​ shown in (B) of, by moving the piston portion 30 (refer to ​ ), the oil flowing toward the inner flow path 111 flows into the main flow path 71.

[0139] Moreover, the oil flowing into the main flow path 71 flows into the back pressure chamber 100P from the hole portion 511.

[0140] Here, in ​In the example shown in (B), the oil in the back pressure chamber 100P hardly flows out from the hole flow path 851 of the orifice plate 85 into the inflow chamber 631. Therefore, the pressure of the oil in the back pressure chamber 100P becomes relatively high.

[0141] Moreover, the oil flowing into the main flow path 71 flows in the gap between the valve seat portion 73 and the main valve 51 while the main valve 51 deforms so as to separate from the valve seat portion 73. However, in ​ the example shown in (B), the pressure in the back pressure chamber 100P is relatively high. Therefore, the main valve 51 bears the pressure of the back pressure chamber 100P and is pressed relatively strongly toward the valve seat portion 73. Therefore, the main valve 51 opens the valve seat portion 73 and makes it difficult for the oil in the main flow path 71 to flow. Therefore, in ​ the outer attenuation portion 100 in the state shown in (B), the generated attenuation force becomes relatively high.

[0142] After that, the oil flowing out by opening the main valve 51 from the main flow path 71 flows in the order of the outer flow path 79, the inner flow path 121 in the housing, and the outer flow path 112, and flows out to the storage chamber R.

[0143] As described above, in the outer attenuation portion 100 of the first embodiment, by changing the pressure of the oil in the back pressure chamber 100P using the adjustment portion 90, the magnitude of the attenuation force generated by the main valve 51 can be adjusted.

[0144] As described above, in the outer attenuation portion 100 of the first embodiment, the force in the direction in which the main valve 51 closes the main flow path 71 is determined by the pressure of the oil in the back pressure chamber 100P and is also determined by the spring force based on the external force of the main valve 51. And, as ​ shown, the main valve 51 has a different structure from the prior art, and the outer edge portion is supported by the valve seat portion 73 of the second housing 70 and the first valve contact portion 673 of the first housing 60 whose position in the second axial direction is not affected by other components. The force in the direction in which the main valve 51 closes the main flow path 71 is determined by the relative position in the second axial direction between the valve seat portion 73 and the first valve contact portion 673. Therefore, if the tolerance of the relative position of the first housing 60 and the second housing 70 is managed, the spring force based on the external force of the main valve 51 can also be managed, and the manufacturability is improved. Moreover, the deviation of the attenuation force due to individual differences of the outer attenuation portion 100 according to the first embodiment is reduced.

[0145] In addition, the management of tolerances can be implemented as follows, for example: by using a measuring instrument or the like to measure the relative positions of the first valve contact portion 673 of the first housing 60 and the valve seat portion 73 of the second housing 70, and managing in such a way that the difference in these positions converges within a range where individual differences do not occur. As a method, the following can be exemplified: selecting a gasket 80 with a specific thickness from among gaskets 80 of multiple thicknesses in such a way that it converges within a range where individual differences do not occur. Additionally, in the case where the gasket 80 is not used, the following can be exemplified: dividing the first housing 60 and the second housing 70 into multiple groups according to dimensions, and selecting and mating them in such a way that it converges within a range where individual differences do not occur. Further, the following can be exemplified: the joining position of the first housing 60 and the second housing 70 in the second axial direction is adjusted by the depth of press-fitting and screw fastening.

[0146] <Second Embodiment>

[0147] Next, the hydraulic shock absorber 1 of the second embodiment will be described in detail. In addition, in the description of the second embodiment, the same reference numerals are given to the same structures as those in the first embodiment, and their detailed descriptions are omitted.

[0148] ​ is a perspective view of the outer damping portion 100 of the second embodiment, which is a partial cross-sectional view.

[0149] ​ is an explanatory view of the orifice plate 285 and the pilot valve 290 of the second embodiment.

[0150] As ​ shown, the outer damping portion 100 of the second embodiment includes: a main valve portion 250 that controls the flow of oil, a first housing 60 (an example of a first housing portion), and a second housing 270 (an example of a second housing portion) provided on the opposite side of the first housing 60 in the second axial direction. And, the outer damping portion 100 of the second embodiment includes: a gasket 80, an orifice plate 285 provided inside the first housing 60, a pilot valve 290 provided on the outer side of the second axis of the orifice plate 285, and an adjustment portion 90. And, similar to the first embodiment, the outer damping portion 100 of the second embodiment includes a connection flow path portion 110 and an outer housing 120 (refer to ​ ).

[0151] (Main Valve Portion 250)

[0152] The main valve portion 250 (an example of a spool portion) of the second embodiment has a main valve 252 (an example of a pressure-receiving portion) that mainly generates damping force and a leaf spring 253 (an example of an elastic portion) that supports the main valve 252 in the outer damping portion 100.

[0153] The main valve 252 is a disk-shaped member. Also, the main valve 252 has a hole portion 52F provided on the inner side in the second radial direction and a pressure receiving portion 52R provided on the inner side of the second axis. In addition, the main valve 252 has a spring receiving portion 52S that receives the leaf spring 253. And the main valve 252 has a first opposing portion 521 provided on the outer side in the second radial direction of the pressure receiving portion 52R and a second opposing portion 522 provided on the outer side in the second radial direction of the first opposing portion 521.

[0154] The flow path cross-sectional area of the hole portion 52F is formed to be sufficiently small compared to the main flow path 71, for example. And the hole portion 52F can achieve the flow of oil from the main flow path 71 to the back pressure chamber 100P even in a state where the main valve 252 is in contact with the first valve seat portion 273 and the second valve seat portion 274 described later and the main flow path 71 is closed.

[0155] The pressure receiving portion 52R is provided so as to face the main flow path 71. And the pressure receiving portion 52R forms a portion that receives the pressure of the oil flowing into the main flow path 71. The main valve 252 receives the pressure of the oil through the pressure receiving portion 52R, whereby it can be displaced toward the outer side of the second axis while elastically deforming the leaf spring 253.

[0156] The spring receiving portion 52S is a circular surface facing the outer side of the second axis. The spring receiving portion 52S is located on the inner side of the second axis with respect to the leaf spring 253. And the spring receiving portion 52S supports the inner side of the second axis of the leaf spring 253.

[0157] The first opposing portion 521 is formed to project annularly toward the inner side of the second axis. And the first opposing portion 521 opposes the first valve seat portion 273 of the second housing 270 described later.

[0158] The second opposing portion 522 is formed to project annularly toward the inner side of the second axis. And the second opposing portion 522 opposes the second valve seat portion 274 of the second housing 270 described later.

[0159] And the first opposing portion 521 and the second opposing portion 522 respectively open and close the first valve seat portion 273 and the second valve seat portion 274 described later, thereby controlling the flow rate of the oil flowing in the main flow path 71 and generating a differential pressure. Thus, the main valve 252 generates the damping force of the hydraulic buffer device 1.

[0160] The leaf spring 253 is formed in a substantially circular and relatively thin plate shape. That is, the leaf spring 253 is formed in a substantially disk shape. In addition, a metal such as iron can be used as the material of the leaf spring 253. And the leaf spring 253 is configured to be elastically deformable.

[0161] The leaf spring 253 has an open opening portion 53H on the inner side in the second radial direction. A part of the main valve 252 is inserted into the opening portion 53H.

[0162] Further, the leaf spring 253 is supported by the first housing 60 and the second housing 270 at its outer edge portion which is the outer side in the second radial direction.

[0163] (Second housing 270)

[0164] The second housing 270 of the second embodiment has: a main flow path 71 through which oil flows, a first valve seat portion 273 provided at the end portion outside the second axis of the main flow path 71, and a second valve seat portion 274 provided on the outer side in the second radial direction of the first valve seat portion 273. Further, the second housing 270 has: a second gasket contact portion 74, a second valve contact portion 75, a second connection portion 76, a groove portion 77, and an outer flow path 79.

[0165] The first valve seat portion 273 is formed to project annularly toward the outside of the second axis. And the first valve seat portion 273 forms a contact portion that contacts the first opposed portion 521 of the main valve 252.

[0166] Further, the second valve seat portion 274 is formed to project annularly toward the outside of the second axis. And the second valve seat portion 274 forms a contact portion that contacts the second opposed portion 522 of the main valve 252. In addition, in the present embodiment, the protruding height of the second valve seat portion 274 is substantially equal to that of the first valve seat portion 273.

[0167] And, between the first valve seat portion 273, the second valve seat portion 274, the first opposed portion 521, and the second opposed portion 522 that respectively project toward the outside of the second axis, an annular space 275 is formed that is annular and recessed toward the inside of the second axis.

[0168] And, the first valve seat portion 273 has a plurality of groove portions 273T formed along the second radial direction. The flow path cross-sectional area of the oil in each groove portion 273T is formed to be relatively small. That is, the groove portions 273T constitute so-called holes. And, in a state where the first opposed portion 521 of the main valve 252 contacts the first valve seat portion 273, each groove portion 273T forms a path for oil to flow from the inner side in the second radial direction of the first valve seat portion 273 to the outer side in the second radial direction of the first valve seat portion 273. That is, in a state where the main valve 252 contacts the first valve seat portion 273, each groove portion 273T allows the oil in the main flow path 71 to flow into the annular space 275 between the first valve seat portion 273 and the second valve seat portion 274.

[0169] (Orifice plate 285)

[0170] As ​ shown in (A) of, the orifice plate 285 has: an outer seat portion 86 provided on the outer side in the second radial direction; and an inner pilot flow path 87 and a plurality of outer pilot flow paths 88 that constitute a path for adjusting the back pressure chamber 100P (refer to ​The oil flow path of the oil under pressure in ().

[0171] The outer seat portion 86 protrudes annularly toward the outside of the second axis with respect to the substantially circular surface provided outside the second axis, that is, the bottom surface portion 285B. And, the outer seat portion 86 supports the outer edge portion of the pilot valve 290.

[0172] The inner pilot flow path 87 is provided inside the second radial direction of the pilot valve 290. And, the inner pilot flow path 87 is provided through the orifice plate 285 in the second axial direction. In addition, the inner pilot flow path 87 has an inner circular member 87R that forms a contact portion in contact with the pilot valve 290 outside the second axis.

[0173] A plurality of outer pilot flow paths 88 are provided in the orifice plate 285 of the second embodiment. Specifically, the orifice plate 285 of the second embodiment includes: a first outer pilot flow path 881, a second outer pilot flow path 882, and a third outer pilot flow path 883. In addition, in the following description, when not distinguishing between the first outer pilot flow path 881, the second outer pilot flow path 882, and the third outer pilot flow path 883 from each other, they are collectively referred to as the outer pilot flow path 88.

[0174] And, each outer pilot flow path 88 has an outer circular member 88R that forms a contact portion in contact with the pilot valve 290 outside the second axis.

[0175] When taking the bottom surface portion 285B as a reference, the heights of the respective outer circular members 88R of the plurality of outer pilot flow paths 88 are substantially equal.

[0176] And, the heights of the outer circular members 88R of the plurality of outer pilot flow paths 88 are lower than the height of the inner circular member 87R of the inner pilot flow path 87 respectively.

[0177] And, the inner diameters of the flow port openings of the plurality of outer pilot flow paths 88 of the orifice plate 285 of the second embodiment are different respectively. That is, the flow path cross-sectional areas of the flow port openings through which the oil supply flows in the plurality of outer pilot flow paths 88 are different respectively.

[0178] Specifically, as ​ shown in (A) of, the inner diameter d1 of the flow port opening of the first outer pilot flow path 881 is larger than the inner diameter d2 of the flow port opening of the second outer pilot flow path 882 and the inner diameter d3 of the flow port opening of the third outer pilot flow path 883. In addition, the inner diameter d2 of the flow port opening of the second outer pilot flow path 882 is larger than the inner diameter d3 of the flow port opening of the third outer pilot flow path 883. That is, the flow path cross-sectional areas of the flow port openings of the plurality of outer pilot flow paths 88 become larger in the order of the third outer pilot flow path 883, the second outer pilot flow path 882, and the first outer pilot flow path 881.

[0179] In addition, the flow path cross-sectional area of the flow path opening of each outer pilot flow path 88 is smaller than the flow path cross-sectional area of the flow path opening of the inner pilot flow path 87.

[0180] - Pilot valve 290-

[0181] As ​ shown in (A) of, the pilot valve 290 is a plate-like member having a substantially circular shape that elastically deforms. As the material of the pilot valve 290, for example, a metal such as iron can be used. Further, the pilot valve 290 is disposed to face the outside of the second axis of the orifice plate 285.

[0182] The pilot valve 290 has: a first opposed portion 81 that opposes the inner pilot flow path 87; and a second opposed portion 82 that opposes the outer pilot flow path 88. Further, the pilot valve 290 has: an inner opening 83 that facilitates deformation of the pilot valve 290 in the second axial direction; and an outer opening 84 that is provided at a position radially outside the inner opening 83 in the second radial direction and facilitates deformation of the pilot valve 290 in the second axial direction.

[0183] As ​ shown in (B) of, the first opposed portion 81 is formed in a circular shape and is plate-like. Further, the first opposed portion 81 can cover the inner circular member 87R.

[0184] The second opposed portion 82 is formed in an annular shape and is plate-like. Further, the second opposed portion 82 can cover the outer circular member 88R.

[0185] Further, in the second embodiment, the regulating valve 91 of the regulating portion 90 regulates the flow rate of the oil flowing in the inner pilot flow path 87 and the outer pilot flow path 88 via the pilot valve 290. Further, the regulating valve 91 regulates the pressure of the oil in the back pressure chamber 100P.

[0186] Next, the functions of the orifice plate 285 and the pilot valve 290 in the second embodiment will be described.

[0187] ​ The main valve portion 250 shown in determines the ease of opening of the main flow path 71 based on the pressure of the oil in the back pressure chamber 100P. When the main valve portion 250 opens the main flow path 71, the oil in the back pressure chamber 100P flows into the inflow chamber 631 from the inner pilot flow path 87 and the plurality of outer pilot flow paths 88.

[0188] Here, the portion of the pilot valve 290 having a larger pressure-receiving area is more easily deformed. Therefore, the oil flowing in each outer pilot flow path 88 opens the pilot valve 290 and flows out with a time difference in the order of the first outer pilot flow path 881, the second outer pilot flow path 882, and the third outer pilot flow path 883. Further, finally, the oil flowing in the inner pilot flow path 87 opens the pilot valve 290 and flows into the inflow chamber 631.

[0189] Moreover, in the outer attenuation section 100 of the second embodiment, for example, compared with the case where the hole flow path 851 is single as in the first embodiment, the change in the oil pressure in the back pressure chamber 100P is stepwise. Due to this stepwise change in the oil pressure in the back pressure chamber 100P, the main valve section 250 does not open the main flow path 71 all at once, but opens it step by step.

[0190] Regarding the outer attenuation section 100 of the second embodiment configured as described above, the basic flow of the oil that opens the main valve section 250 is the same as that of the above-described first embodiment.

[0191] Here, in the outer attenuation section 100 of the second embodiment, the second housing 270 has a first valve seat portion 273 and a second valve seat portion 274. And the first valve seat portion 273 of the second housing 270 has a plurality of groove portions.

[0192] As a result, regarding the outer attenuation section 100 of the second embodiment, the pressure-receiving area of the main valve section 250 with respect to the oil flowing in the main flow path 71 changes step by step. And in the main valve section 250 of the second embodiment, when the main valve 252 is opened in the main flow path 71 and the oil supply flows, the attenuation force does not change abruptly, but a stepwise-changing attenuation force characteristic is obtained.

[0193] Moreover, as described above, in the outer attenuation section 100 of the second embodiment, the force in the direction of closing the main flow path 71 of the main valve 252 by the leaf spring 253 is also determined by the relative positions of the first valve seat portion 273 and the second valve seat portion 274 and the first valve contact portion 673 in the second axial direction. Therefore, if only the relative positions of the first housing 60 and the second housing 270 are managed for tolerances, the spring force based on the external force of the main valve 252 can also be managed simultaneously, improving manufacturability. And the deviation of the attenuation force due to individual differences in the outer attenuation section 100 of the second embodiment is reduced.

[0194] <Third Embodiment>

[0195] Next, the hydraulic shock absorber 1 of the third embodiment will be described in detail. In addition, in the description of the third embodiment, the same reference numerals are given to the same structures as those in other embodiments, and their detailed descriptions are omitted.

[0196] ​ It is a perspective view of the outer attenuation section 100 of the third embodiment, which is a partial cross-sectional view.

[0197] As ​As shown, the outer damping portion 100 of the third embodiment includes: a main valve portion 50 that controls the flow of oil; a first housing 360 (an example of a first housing portion); and a second housing 70 (an example of a second housing portion) that is provided on the opposite side of the first housing 360 in the second axial direction. Further, the outer damping portion 100 of the third embodiment includes: a gasket 80; an orifice plate 385 that is provided inside the first housing 360; and an adjustment portion 390 that adjusts the back pressure of the back pressure chamber 100P. And, like the first embodiment, the outer damping portion 100 of the third embodiment includes a connecting flow path portion 110 and an outer housing 120 (refer to ​ ).

[0198] (First housing 360)

[0199] The first housing 360 has: an opening portion 361 provided outside the second axis, a housing portion 363 that houses a later-described push rod 391 of the adjustment portion 390, a holding portion 65, and an opposing portion 67.

[0200] The opening portion 361 supports a later-described push rod 391 of the adjustment portion 390 so as to be movable along the second axial direction.

[0201] The housing portion 363 houses inside a later-described push rod 391 of the adjustment portion 90 and a compression coil spring 392. Further, the housing portion 363 forms an inflow chamber 363R into which the oil flowing in the hole flow path 851 of the orifice plate 385 flows. And, the housing portion 363 has a plurality of through holes 363H that penetrate along the second radial direction. The through holes 363H communicate the inflow chamber 363R with a later-described inner housing flow path 121 (refer to ​ ).

[0202] (Orifice plate 385)

[0203] The orifice plate 385 is formed in a substantially circular shape and plate shape. And, the orifice plate 385 is press-fitted inside the first housing 360 and held by the holding portion 65.

[0204] Further, the orifice plate 385 has a hole flow path 851 for the oil to flow and a valve opposing portion 385R provided outside the second axis of the hole flow path 851.

[0205] The valve opposing portion 385R is formed by a conical opening. The valve opposing portion 385R communicates with the hole flow path 851. Further, the valve opposing portion 385R is provided to oppose a later-described push rod 391.

[0206] (Adjustment portion 390)

[0207] The adjustment portion 390 has: a push rod 391 that controls the flow of the oil in the hole flow path 851; and a compression coil spring 392 provided between the push rod 391 and the first housing 360.

[0208] The push rod 391 is a rod-shaped member that extends relatively long along the second axis. The push rod 391 is supported by the first housing 360 so as to be movable along the second axis. Further, the push rod 391 has a valve portion 391V formed in a conical shape at the end portion inside the second axis. And, the push rod 391 adjusts the flow rate of the oil flowing in the hole flow path 851 by changing the distance between the valve portion 391V and the valve opposing portion 385R.

[0209] The inside of the second axis of the compression coil spring 392 is hooked on the push rod 391, and the outside of the second axis contacts the first housing 360. And, the compression coil spring 392 imparts a spring force to the push rod 391 that causes the push rod 391 to approach the valve opposing portion 385R.

[0210] Regarding the outer attenuation portion 100 of the third embodiment configured as described above, the basic flow of the oil is the same as that of the first embodiment described above.

[0211] However, in the outer attenuation portion 100 of the third embodiment, the adjustment of the pressure of the oil in the back pressure chamber 100P by the adjustment portion 390 is different from other embodiments. In the outer attenuation portion 100 of the third embodiment, the push rod 391 operates according to the flow of the oil in the hole flow path 851 to adjust the oil pressure in the back pressure chamber 100P.

[0212] In the outer attenuation portion 100, when the flow rate of the oil in the hole flow path 851 is relatively large, the push rod 391 compresses the compression coil spring 392 and displaces toward the outside of the second axis. That is, the distance between the valve portion 391V and the valve opposing portion 385R becomes relatively far. And, the oil in the back pressure chamber 100P easily flows out to the inflow chamber 363R through the hole flow path 851. As a result, the back pressure in the back pressure chamber 100P becomes relatively low. Along with this, the main valve 51 is easily opened to the main flow path 71.

[0213] On the other hand, in the outer attenuation portion 100, when the flow rate of the oil in the hole flow path 851 is relatively small, the distance between the valve portion 391V and the valve opposing portion 385R becomes relatively close. And, the oil in the back pressure chamber 100P hardly flows out to the inflow chamber 363R. As a result, the back pressure of the oil in the back pressure chamber 100P becomes relatively high. Along with this, the main valve 51 is difficult to open the main flow path 71.

[0214] As described above, when adjusting the pressure of the oil in the back pressure chamber 100P, the adjustment portion 390 of the outer attenuation portion 100 of the third embodiment is not adjusted electronically like the adjustment portion 90 of other embodiments, but is adjusted mechanically according to the oil flow rate.

[0215] In addition, in the outer attenuation portion 100 of the third embodiment, by changing the specifications of the compression coil spring 392, it is possible to easily set the oil pressure in the back pressure chamber 100P corresponding to the oil flow rate in the hole flow path 851.

[0216] Moreover, in the outer attenuation portion 100 of the third embodiment configured as described above, if the tolerances of the relative positions of the first housing 360 and the second housing 70 are managed, the spring force based on the external force of the main valve 51 can also be managed, improving manufacturability. Also, the deviation of the attenuation force due to individual differences in the outer attenuation portion 100 of the third embodiment is reduced.

[0217] <Fourth Embodiment>

[0218] Next, the hydraulic shock absorber 1 of the fourth embodiment will be described in detail. In addition, in the description of the fourth embodiment, the same reference numerals are given to the same structures as those in other embodiments, and their detailed descriptions are omitted.

[0219] ​ It is an overall view of the hydraulic shock absorber 1 of the fourth embodiment.

[0220] ​ It is a cross-sectional view of the piston portion 230 of the fourth embodiment.

[0221] As ​ shown, the hydraulic shock absorber 1 of the fourth embodiment includes a piston portion 230 on one side in the axial direction of the rod 20 and inside the cylinder portion 10. In addition, the basic structure of the piston portion 230 of the fourth embodiment is the same as that of the main valve portion 50, the first housing 60, and the second housing 70 of the first embodiment. Hereinafter, a specific description will be given.

[0222] As ​ shown, the piston portion 230 has: a piston body 231, a first valve 232 provided on one side of the piston body 231, and a second valve 233 provided on the other side of the piston body 231.

[0223] When the rod 20 moves to the other side in the axial direction, when oil flows from the second oil chamber Y2 to the first oil chamber Y1 through the first oil passage 234, the first valve 232 restricts the oil flow rate in the first oil passage 234 to generate a differential pressure. On the other hand, when the rod 20 moves to one side in the axial direction, when oil flows from the first oil chamber Y1 to the second oil chamber Y2 through the second oil passage 235, the second valve 233 restricts the oil flow rate in the second oil passage 235 to generate a differential pressure.

[0224] Further, the piston portion 230 includes: a main valve portion 50, a first housing 60, a second housing 70, and a gasket 80. In addition, the piston portion 230 has a flexure valve 700 that is disposed within the back pressure chamber 100P and flexes, and a holding valve 800 that holds the main valve portion 50 and the flexure valve 700, respectively.

[0225] The flexure valve 700 is a plate-shaped elastic member. Further, the flexure valve 700 is deformable according to the pressure in the back pressure chamber 100P.

[0226] The holding valve 800 is an elastic member. Further, the holding valve 800 has a plurality of legs 800F that protrude toward one side and the other side in the axial direction, respectively. The holding valve 800 is disposed between the main valve 51 and the flexure valve 700. Further, the holding valve 800 holds the main valve 51 and the flexure valve 700 by the legs 800F.

[0227] In addition, the piston portion 230 of the fourth embodiment does not necessarily need to include the holding valve 800. On the other hand, when the holding valve 800 is provided in the piston portion 230, for example, the legs 800F may not contact the main valve 51, and the legs 800F may contact the first housing 60.

[0228] And, as ​ shown, the rod 20 of the fourth embodiment has a bypass oil passage 20A therein. The bypass oil passage 20A is a flow passage corresponding to the main flow passage 71 of the first embodiment. Further, the bypass oil passage 20A passes through the inner side in the radial direction of the second housing 70 and faces the other side in the axial direction of the main valve 51.

[0229] In the hydraulic shock absorber 1 of the fourth embodiment configured as described above, when the rod 20 moves to the other side in the axial direction, the oil in the second oil chamber Y2 flows into the other side in the axial direction of the main valve 51 through the bypass oil passage 20A. A part of the oil flows into the back pressure chamber 100P through the hole portion 511 of the main valve 51.

[0230] Further, the flexure valve 700 flexes to the deformation limit corresponding to the pressure in the back pressure chamber 100P and functions so that the pressure in the back pressure chamber 100P does not increase. In addition, for example, the state in which the flexure valve 700 contacts the bottom surface portion 60B of the first housing 60 becomes the deformation limit. Further, when the flexure valve 700 deforms toward the bottom surface portion 60B, the oil on the one side in the axial direction of the flexure valve 700 flows out from the through hole 60H to the first oil chamber Y1 side.

[0231] In this way, before the flexure valve 700 reaches the deformation limit, the pressure in the back pressure chamber 100P is maintained at a low level. Therefore, the back pressure applied to the main valve 51 becomes lower. And since no back pressure is applied to the main valve 51, the main valve 51 is easily opened by the oil flowing in the bypass oil passage 20A. Also, in this state, the damping force generated in the main valve 51 is relatively low.

[0232] On the other hand, when the flexure valve 700 flexes to the deformation limit, the pressure in the back pressure chamber 100P becomes higher. As a result, then, the back pressure applied to the main valve 51 becomes higher, so it is difficult for the main valve 51 to be opened by the oil flowing in the bypass oil passage 20A. Also, in this state, the damping force generated in the main valve 51 becomes relatively high.

[0233] Furthermore, in the hydraulic shock absorber 1 of the fourth embodiment configured as described above, when the rod 20 moves to one side in the axial direction, the flexure valve 700 deforms toward the other side by the oil flowing from the first oil chamber Y1 into the through hole 60H. In addition, the main valve 51 is pressed against the second housing 70.

[0234] In the piston portion 230 of the fourth embodiment configured as described above, if the tolerance of the relative positions of the first housing 60 and the second housing 70 is managed, the spring force based on the external force of the main valve 51 can also be managed, and the manufacturability is improved. Also, the deviation of the damping force due to the individual differences of the piston portion 230 of the fourth embodiment is reduced.

[0235] <Deformation Example>

[0236] Next, the outer damping portion 100 of the deformation example will be described.

[0237] For example, in the first embodiment, ​ the orifice plate 85 shown may also have a protruding portion that protrudes cylindrically toward the inside of the second axis at the end on the outer side in the second radial direction of the orifice plate 85. And the cylindrically protruding portion of the orifice plate 85 may also contact the outer edge portion of the main valve 51. Thus, the orifice plate 85 may also form a part of the back pressure chamber 100P and support the outer edge portion of the main valve 51.

[0238] Furthermore, in the above-described embodiment, the gasket 80 is formed separately from the first housing 60 and the second housing 70, but it may be formed integrally with the first housing 60 or the second housing 70.

[0239] In addition, the second valve contact portion 75 of the second housing 70 may be configured to always contact the main valve 51, or may be configured to contact when the main valve 51 flexes a predetermined amount toward the inside of the second axis due to the pressure in the back pressure chamber 100P.

[0240] In addition, the second valve contact portion 75 of the second housing 70 may also be formed of other components. In this case, the other components may also be configured to have an annular portion formed in a ring shape and a plurality of arm portions protruding inward in the second radial direction from the annular portion. Further, the arm portions of the other components may also be shaped such that they taper and extend toward the inner end in the second radial direction. In this case, for example, the outer edge portion of the main valve 51 can be deformed inward in the second axial direction. Also, the main valve 51 is easily flexed. As a result, the lower limit of the opening pressure of the main valve 51 decreases, and the adjustment range of the damping force can be widened.

[0241] In addition, in the above-described first embodiment, second embodiment, third embodiment, fourth embodiment, and modification, all or part of the structures described in one embodiment or the like may be applied to other embodiments or combined.

[0242] Reference Signs

[0243] 1: Hydraulic shock absorber; 11: Cylinder; 20: Rod; 30: Piston portion; 50: Main valve portion; 51: Main valve; 60: First housing; 70: Second housing; 71: Main flow path; 73: Valve seat portion; 75: Second valve contact portion; 80: Gasket; 85: Orifice plate; 90: Adjustment portion; 100: Outer damping portion; 100P: Back pressure chamber; 230: Piston portion; 673: First valve contact portion.

Claims

1. A damping force generating mechanism having a flow path inside for fluid flow, comprising: A spool portion having an elastic portion that can elastically deform and is plate-shaped, and a pressure-receiving portion that receives the pressure of the fluid; A valve seat portion provided around the flow port of the flow path and capable of contacting the pressure-receiving portion; A first accommodating portion that constitutes at least a part of the back pressure chamber and supports the outer edge portion of the elastic portion, and the back pressure chamber applies a back pressure to the spool portion toward the valve seat portion; A contact portion provided at a position outside the valve seat portion and capable of contacting the elastic portion of the spool portion; and A concave portion provided at a position outside the contact portion to allow the outer edge portion of the elastic portion to shift.

2. The damping force generating mechanism according to claim 1, wherein The elastic portion of the spool portion is supported by the first accommodating portion and the valve seat portion.

3. The damping force generating mechanism according to claim 1, wherein The valve seat portion is provided in a second accommodating portion, and the second accommodating portion is provided on the opposite side of the first accommodating portion with respect to the spool portion and at least accommodates the spool portion.

4. The damping force generating mechanism according to claim 1, wherein The contact portion is provided in a second accommodating portion, and the second accommodating portion is provided on the opposite side of the first accommodating portion with respect to the spool portion and at least accommodates the spool portion.

5. The damping force generating mechanism according to claim 1, wherein The damping force generating mechanism includes a setting portion sandwiched between the first accommodating portion and the second accommodating portion to determine the interval between the first accommodating portion and the second accommodating portion. The second accommodating portion is provided on the opposite side of the first accommodating portion with respect to the spool portion and at least accommodates the spool portion.

6. The damping force generating mechanism according to claim 1, wherein The elastic portion and the pressure-receiving portion of the spool portion are integrally formed.

7. The damping force generating mechanism according to claim 2, wherein The valve seat portion is provided in a second accommodating portion, and the second accommodating portion is provided on the opposite side of the first accommodating portion with respect to the spool portion and at least accommodates the spool portion.

8. The damping force generating mechanism according to claim 2, wherein The contact portion is provided in a second accommodating portion, and the second accommodating portion is provided on the opposite side of the first accommodating portion with respect to the spool portion and at least accommodates the spool portion.

9. The damping force generating mechanism according to claim 2, wherein The damping force generating mechanism includes a setting portion sandwiched between the first accommodating portion and the second accommodating portion to determine the interval between the first accommodating portion and the second accommodating portion. The second accommodating portion is provided on the opposite side of the first accommodating portion with respect to the spool portion and at least accommodates the spool portion.

10. The damping force generating mechanism according to claim 2, wherein The elastic portion and the pressure-receiving portion of the spool portion are integrally formed.

11. The damping force generating mechanism according to claim 3, wherein The contact portion is disposed in the second accommodating portion. The second accommodating portion is disposed on the opposite side of the first accommodating portion with respect to the valve core portion and at least accommodates the valve core portion.

12. The damping force generating mechanism according to claim 3, wherein the damping force generating mechanism includes a setting portion that is sandwiched between the first accommodating portion and the second accommodating portion and determines the interval between the first accommodating portion and the second accommodating portion. The second accommodating portion is disposed on the opposite side of the first accommodating portion with respect to the valve core portion and at least accommodates the valve core portion.

13. The damping force generating mechanism according to claim 3, wherein the elastic portion and the pressure receiving portion of the valve core portion are integrally formed.

14. The damping force generating mechanism according to claim 4, wherein the damping force generating mechanism includes a setting portion that is sandwiched between the first accommodating portion and the second accommodating portion and determines the interval between the first accommodating portion and the second accommodating portion. The second accommodating portion is disposed on the opposite side of the first accommodating portion with respect to the valve core portion and at least accommodates the valve core portion.

15. The damping force generating mechanism according to claim 4, wherein the elastic portion and the pressure receiving portion of the valve core portion are integrally formed.

16. The damping force generating mechanism according to claim 5, wherein the elastic portion and the pressure receiving portion of the valve core portion are integrally formed.

17. A pressure buffering device, comprising: a cylinder that accommodates a fluid; a piston portion that is connected to a rod that moves axially and moves within the cylinder; a flow path forming portion that forms a flow path for the fluid to flow as the piston portion moves; a valve core portion that has an elastic portion that can elastically deform and is plate-shaped and a pressure receiving portion that receives the pressure of the fluid; a valve seat portion that is disposed around the flow port of the flow path and can contact the pressure receiving portion; a first accommodating portion that constitutes at least a part of the back pressure chamber and supports the outer edge portion of the elastic portion. The back pressure chamber applies a back pressure to the valve core portion toward the valve seat portion; a contact portion that is disposed at a position outside the valve seat portion and can contact the elastic portion of the valve core portion; and a concave portion that is disposed at a position outside the contact portion and allows the outer edge portion of the elastic portion to be displaced.

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