Linear damper and steering device

Abstract

To provide a direct-acting damper and steering device with the direct-acting damper, capable of avoiding enlargement of the equipment constitution of an attachment object and capable of increasing the types of attachment objects that can be attached.SOLUTION: A steering device 100 includes a direct-acting damper 120 between a rack bar 103 and a rack end 106. The direct-acting damper 120 has an inner chamber 121 formed between a socket body 107 inside an inner chamber formation body 130 and itself. The socket body 107 is an axial component forming a rack end 106 in the steering device 100 and is fitted to be slidable on the inner chamber formation body 130. The inner chamber formation body 130 is formed into a cylindrical shape and has formed therein a circulation control valve 140 in an annular shape in an inner-peripheral part. The circulation control valve 140 includes: a first circulation control valve 150; a second control valve 160; and a third circulation control valve 170.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention provides a flow control valve that controls the flow of a fluid by restricting the flow of the fluid while allowing it to flow. and a steering device equipped with the linear damper. Regarding. [Background technology]

[0002] A prior art document disclosing this type of technology is the following Patent Document 1. Patent Document 1 discloses a steering device that can absorb strong impacts, such as when a self-propelled vehicle runs over a curb, by providing an impact absorbing member made of rubber and metal between a rack housing that covers the rack shaft and a tie rod that connects to the wheels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-97840 Summary of the Invention

[0004] However, in the steering device disclosed in Patent Document 1, the shock absorbing member is made of rubber or synthetic resin, and therefore there is a problem in that the magnitude of the shock that can be absorbed is small.

[0005] The present invention has been made to address the above-mentioned problems, and its purpose is to provide a vehicle that can absorb large impact forces. A steering device and a direct acting damper applicable to this steering device The purpose is to provide.

[0006] In order to achieve the above object, the present invention is characterized by: The linear damper has an inner chamber forming body having an inner chamber that fluid-tightly accommodates a fluid, and attenuates an external force received by the fluid by restricting the flow of the fluid. The linear damper comprises: a rod-shaped relative displacement body that is displaced relative to the inner chamber forming body; a flow control valve that is provided on at least one of the inner chamber forming body and the relative displacement body and controls the flow of the fluid by restricting the flow of the fluid while allowing it to flow; and a return elastic body that imparts elastic force. The inner chamber is formed in an annular cylindrical shape outside the relative displacement body, and the flow control valve is formed on a ring-shaped valve support that fits into the annular cylindrical inner chamber. The linear damper comprises a first circulating body having a first circulating hole that allows the fluid to circulate; a second circulating body that is arranged opposite the first circulating body and has a second circulating hole that allows the fluid to circulate; and a return elastic body that applies elastic force. and a separating elastic body that exerts an elastic force to move away from a position where the first and second circulating bodies contact each other, at least one of the first and second circulating bodies has a hole diameter restricting portion that blocks at least a portion of at least one of the second and first circulating holes when the first and second circulating bodies contact each other, the returning elastic body applies an elastic force to allow fluid to flow from the first circulating body side to the second circulating body side of the flow control valve, and applies an elastic force to one of the inner chamber forming body and the relative displacement body to displace one relative to the other, the inner chamber forming body is formed in a cylindrical shape that slidably fits into the relative displacement body and is displaced relative to the inner chamber together with the flow control valve via the flow control valve. This allows the direct-acting damper to absorb large impact forces.

[0007] The present invention also provides Not only can it be implemented as an invention of a direct acting damper, but also as a steering device equipped with this direct acting damper. The present invention can also be implemented as the above invention.

[0008] Specifically, the steering device is a steering device including a steering shaft formed to extend in a rod-like shape and rotated by operation of a steering wheel, a rack bar formed to extend in a rod-like shape and converting the rotational motion of the steering shaft into a reciprocating motion in the axial direction and transmitting the motion, intermediate connectors connected to both ends of the rack bar and connecting the wheels to be steered directly or indirectly to the both ends, and a rack housing covering the rack bar, The device is provided with an inner chamber forming body having an inner chamber for liquid-tightly storing a fluid, and attenuates external forces received by the fluid by restricting the flow of the fluid. The linear damper is provided between the rack housing and the rack bar or intermediate connector to attenuate impacts from the wheels. It is something that The fluid passage includes a relative displacement body that is displaced relative to the inner chamber forming body, and a flow control valve that is provided on at least one of the inner chamber forming body and the relative displacement body and controls the flow of the fluid by restricting the flow of the fluid while allowing it to flow. And, The flow control valve preferably includes a first flow body having a first flow hole through which the fluid flows, a second flow body disposed opposite the first flow body and having a second flow hole through which the fluid flows, and a separating elastic body that exerts an elastic force to move the first flow body and the second flow body away from each other at positions where they contact each other, and at least one of the first flow body and the second flow body preferably includes a hole diameter restricting portion that closes at least a part of the flow hole of at least one of the second flow hole and the first flow hole when the first flow body and the second flow body contact each other. The above-mentioned direct acting damper Similar effects can be expected.

[0009] Another feature of the present invention is the Steering device In the present invention, the pore diameter restricting portion is provided in only one of the first flow body and the second flow body.

[0010] Another feature of the present invention is the Steering device In the present invention, the pore diameter restricting portion is provided in both the first flow body and the second flow body.

[0011] Another feature of the present invention is the Steering deviceIn the present invention, the hole diameter restricting portion is formed so as to completely block at least one of the second through hole and the first through hole.

[0012] Another feature of the present invention is the In the steering system, the flow control valve Furthermore, a second circulating body accommodating section is provided on the second circulating body side relative to the first circulating body to accommodate the second circulating body in a slidable manner, and the separating elastic body is provided between the first circulating body and the second circulating body within the second circulating body accommodating section.

[0013] Another feature of the present invention is the Steering device In the second flow body, the opening of the second flow hole on the opposite side to the first flow body is formed in a tapered shape such that the size of the hole decreases from the opening side toward the back side.

[0014] Another feature of the present invention is the In the steering device, the flow control valve is Furthermore, a second flow control valve consisting of a one-way valve that circulates fluid through a flow path separate from the first flow body and the second flow body is provided, and the second flow control valve allows the flow of fluid from the first flow body side toward the second flow body side, while blocking the flow of fluid from the second flow body side toward the first flow body side.

[0015] Another feature of the present invention is the In the steering device, the flow control valve is Furthermore, a third flow control valve is provided that restricts the flow of fluid while allowing it to flow in a flow path separate from the first flow body and the second flow body, and the third flow control valve restricts the flow of fluid between the first flow body side and the second flow body side while allowing it to flow.

[0016] In this case, the In a steering device, a direct acting damper is Furthermore, a return elastic body is provided that applies an elastic force to cause the fluid to flow from the first circulating body side to the second circulating body side in the flow control valve, and the return elastic body applies an elastic force to one of the inner chamber forming body and the relative displacement body to displace one relative to the other.

[0017] In these cases, Steering device In the above, the relative displacement body is formed in a rod shape, the inner chamber is formed in a circular cylindrical shape outside the relative displacement body, the flow control valve is formed in a ring-shaped valve support body that fits into the circular cylindrical inner chamber, and the inner chamber forming body is formed in a cylindrical shape that fits freely slidably into the relative displacement body, and is displaced relative to the inner chamber together with the flow control valve via the flow control valve.

[0018] In these cases, In the steering device, The inner chamber forming body is formed in a cylindrical shape, the inner chamber is formed in a circular cylindrical shape inside the inner chamber forming body, the flow control valve is formed in a ring-shaped valve support body that fits into the circular cylindrical inner chamber, and the relative displacement body is formed in a rod shape that fits freely slidably into the inner chamber forming body and is displaced relative to the inner chamber together with the flow control valve via the valve support body.

[0019] In this case, in the steering device, the relative displacement body may be formed on the intermediate connecting body, and the inner chamber forming body may be formed at a position that contacts or moves away from the rack housing due to the reciprocating motion of the rack bar.

[0020] According to this, in the steering device of the present invention, the relative displacement body is formed at the rack end that movably connects the tie rod to the rack bar, the inner chamber forming body is formed at a position that contacts or moves away from the rack housing due to the reciprocating motion of the rack bar, and the linear damper is provided on an intermediate connecting body such as the tie rod or rack end, making it easy to perform maintenance or replacement of the linear damper.

[0021] In this case, in the steering device, the inner chamber forming body is formed at the end of the rack housing, and the relative displacement body has the rack bar or intermediate connector passing through it, and is formed at a position where the rack bar or intermediate connector comes into contact with or separates from the relative displacement body due to the reciprocating motion of the rack bar.

[0022] According to this, in the steering device according to the present invention, the inner chamber forming body is provided at the end of the rack housing, and the relative displacement body is formed so that the rack bar or intermediate connector (tie rod or rack end, etc.) passes through the interior of the relative displacement body and contacts or separates from the rack bar or tie rod due to the reciprocating motion of the rack bar. As a result, in the steering device according to the present invention, the linear damper is provided in the rack housing, making it possible to reduce the weight of the tie rod or intermediate connector (tie rod or rack end, etc.).

[0023] The present invention also provides a flow control valve, A flow control valve for controlling the flow of a fluid by restricting the flow of the fluid includes a first flow body having a first flow hole through which the fluid flows, a second flow body disposed opposite the first flow body and having a second flow hole through which the fluid flows, and a separating elastic body that exerts an elastic force to move the first flow body and the second flow body away from each other at positions where they contact each other, and at least one of the first flow body and the second flow body may include a hole diameter restricting portion that closes at least a portion of at least one of the second flow hole and the first flow hole when the first flow body and the second flow body contact each other. This allows the flow control valve to absorb large impact forces. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is an explanatory diagram that schematically illustrates an outline of the overall configuration of a steering device according to a first embodiment of the present invention. [Figure 2] 2 is a perspective view showing the outline of the external configuration of a linear damper according to a first embodiment of the present invention that constitutes the steering device shown in FIG. 1. FIG. [Figure 3] FIG. 3 is a cross-sectional view showing an outline of the internal configuration of the linear damper shown in FIG. 2. [Figure 4] 4 is a cross-sectional view showing the relative displacement body and the socket body taken along line 4-4 in FIG. 3. FIG. [Figure 5]4 is a partially enlarged view showing in detail the structure within a dashed circle 5 in the linear damper shown in FIG. 3. FIG. [Figure 6] 4 is a cross-sectional view showing a state at the moment when a relative displacement body comes into contact with a rack housing in the linear damper shown in FIG. 3. FIG. [Figure 7] 6 is a partially enlarged view showing a state in which a first flow control valve allows a fluid to flow in the direct-acting damper shown in FIG. 5. FIG. [Figure 8] 6 is a partially enlarged view showing a state in which a first flow control valve does not allow fluid to flow in the direct-acting damper shown in FIG. 5. FIG. [Figure 9] FIG. 5 is a cross-sectional view showing an outline of the internal configuration of a linear damper according to a second embodiment of the present invention. [Figure 10] 10 is a front view showing only the flow control valve as seen from line 10-10 shown in FIG. 9. [Figure 11] 10 is a cross-sectional view showing a state at the moment when a socket body comes into contact with a relative displacement body in the linear damper shown in FIG. 9. FIG. [Figure 12] 10 is a partially enlarged view showing a state in which a first flow control valve allows fluid to flow in a portion indicated by a dashed circle 12 in the direct-acting damper shown in FIG. 9. FIG. [Figure 13] 10 is a partially enlarged view showing a state in which a first flow control valve does not allow fluid to flow in the direct-acting damper shown in FIG. 9. FIG. [Figure 14] FIG. 10 is a cross-sectional view showing an outline of the internal configuration of a linear damper according to a modified example of the present invention. [Figure 15] 15 is a front view showing only the flow control valve as seen from line 15-15 shown in FIG. 14. [Figure 16] FIG. 10 is a cross-sectional view showing an outline of the internal configuration of a linear damper according to another modified example of the present invention. [Figure 17] 10 is a partially enlarged view showing a state in which the first flow control valve does not allow fluid to flow by completely blocking both the first flow hole and the second flow hole in a damper according to a modified example of the present invention. FIG. [Figure 18] FIG. 10 is a partially enlarged view showing a state in which a part of a first through hole and a part of a second through hole overlap each other to ensure the flow of fluid in a damper according to another modified example of the present invention. [Figure 19] FIG. 10 is a partially enlarged view showing a state in which only the second flow hole is completely blocked and the first flow control valve does not allow the fluid to flow in a damper according to another modified example of the present invention. [Figure 20] 10 is a partially enlarged view showing a state in which only the first flow hole is completely blocked and the first flow control valve does not allow the fluid to flow in a damper according to a modified example of the present invention. FIG. [Figure 21] 21 is a partially enlarged perspective view showing the external configuration of the tip end of the second flow body shown in FIG. 20. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] First Embodiment A first embodiment of a linear damper according to the present invention and a steering device including this linear damper will be described below with reference to the drawings. FIG. 1 is an explanatory diagram that schematically illustrates the overall configuration of a steering device 100 according to the first embodiment of the present invention. FIG. 2 is a perspective view that illustrates the outline of the external configuration of a linear damper 120 according to the first embodiment of the present invention that constitutes the steering device 100 shown in FIG. 1. FIG. 3 is a cross-sectional view that illustrates the outline of the internal configuration of the linear damper 120 shown in FIG. 2. FIG. 4 is a cross-sectional view that illustrates an inner chamber forming body 130 and a socket body 107 as viewed from line 4-4 shown in FIG. 3. FIG. 5 is a partially enlarged view that illustrates in detail the structure within a dashed circle 5 in the linear damper 120 shown in FIG. 3.

[0026] The steering device 100 is a mechanical device for steering two front wheels (or rear wheels) of a four-wheeled self-propelled vehicle (not shown) in the left and right directions.

[0027] (Configuration of steering device 100) The steering device 100 includes a steering wheel 101. The steering wheel 101 is an operator (i.e., a handle) that allows the driver of the self-propelled vehicle to manually control the direction of travel, and is made of a resin or metal material formed into an annular shape. A steering shaft 102 is connected to the steering wheel 101.

[0028] The steering shaft 102 is a rod-shaped component that rotates around an axis in response to clockwise or counterclockwise rotation of the steering wheel 101, and is configured by connecting one or more metal rods via universal joints or the like. The steering shaft 102 has the steering wheel 101 connected to one end, and a pinion gear 102a formed at the other end and connected to a rack bar 103.

[0029] The rack bar 103 is a rod-shaped component that transmits the steering force and steering amount for each of the two wheels 112 to the knuckle arms 111 by reciprocating in the axial direction, and is made of metal. In this case, a rack gear 103a is formed on a part of the rack bar 103, and is meshed with a pinion gear 102a of the steering shaft 102. In other words, the pinion gear 102a and the rack gear 103a form a rack and pinion mechanism (steering gearbox) that converts the rotational motion of the steering shaft 102 into the reciprocating linear motion of the rack bar 103.

[0030] The rack bar 103 has both axial ends exposed from the rack housing 104, with the rack and pinion mechanism covered by the rack housing 104. Wheels 112 are connected to both ends of the rack bar 103 exposed from the rack housing 104 via intermediate connectors 105 and knuckle arms 111, respectively.

[0031] The rack housing 104 is a component that covers and protects the main parts such as the rack and pinion mechanism of the rack bar 103, and is made of a cylindrical metal material. The rack housing 104 is fixedly attached to the chassis (not shown) of the self-propelled vehicle.

[0032] The intermediate connector 105 is a component for transmitting the steering force and steering amount transmitted from the rack bar 103 to the knuckle arm 111, and is mainly composed of a rack end 106 and a tie rod 110. The rack end 106 is a component that movably connects the tie rod 110 to the tip end of the rack bar 103 and in which the linear damper 120 is formed, and is mainly composed of a socket body 107 and a stud body 108.

[0033] The socket body 107 is a component that movably connects the stud body 108 to the tip of the rack bar 103 and in which the linear damper 120 is formed, and is configured by forming a metal material into a round bar shape. This socket body 107 has a ball holding portion 107a formed at one end (the right side in the figure) and a male screw portion 107b formed at the other end (the left side in the figure) that screws into the tip of the rack bar 103. The ball holding portion 107a is formed in a concave spherical shape so that it slidably fits and holds the ball portion 108a of the stud body 108. The linear damper 120 is formed between the ball holding portion 107a and the male screw portion 107b of the socket body 107.

[0034] The stud body 108 is a component for movably connecting the tie rod 110 to the socket body 107, and is made of a metal material formed into a round bar shape. The stud body 108 has a spherical ball portion 108a formed at one end (the left side in the figure) and a male thread portion (not shown) that screws onto the end of the tie rod 110 formed at the other end (the right side in the figure).

[0035] The tie rod 110 is a component that movably connects the knuckle arm 111 to the tip of the rack end 106, and is configured by a ball joint movably attached to the tip of a rod-shaped tie rod body. The knuckle arm 111 is a metal component that holds the wheel 112 relative to the tie rod 110 and transmits the steering force and steering amount transmitted from the tie rod 110 to the wheel 112, and is formed in a shape with multiple rod-shaped bodies extending from the periphery of a cylindrical portion. The wheels 112 are a pair of left and right components that roll on the road surface to move the self-propelled vehicle forward or backward, and are configured by rubber tires attached to the outside of metal wheels.

[0036] The linear dampers 120 are devices for absorbing strong pressing forces (impacts) transmitted from the wheels 112, and are formed on the left and right intermediate connectors, more specifically, on the left and right socket bodies 107. The linear dampers 120 include an inner chamber 121.

[0037] The inner chamber 121 is a portion that liquid-tightly accommodates the fluid 124, and is formed in the shape of a circular cylinder that is recessed circumferentially on the outer periphery of the socket body 107 and extends in the axial direction. That is, the socket body 107 constitutes the rack end 106, and is also a component that corresponds to the relative displacement body of the present invention. In this embodiment, the bottom and one end (right side in the figure) of the inner chamber 121 in the axial direction of the socket body 107 are each formed by the socket body 107 itself, and the other end (left side in the figure) in the axial direction is formed by the wall forming body 122. The outside of the inner chamber 121 is covered by an inner chamber forming body 130.

[0038] Wall forming body 122 is a component for forming the wall portion on the left side of inner chamber 121 in the figure, and is made of a metal material formed into an annular shape. Wall forming body 122 is screwed onto the outer peripheral surface of the other side (left side in the figure) of socket body 107 in the axial direction, and is integrated with socket body 107. Furthermore, buffer materials 123a and 123b made of an elastic body constituted by an elastomer such as urethane resin are provided at both ends of socket body 107 in the axial direction in inner chamber 121. In this case, buffer material 123a is formed to be thicker than buffer material 123b.

[0039] The fluid 124 is a substance that provides resistance to the flow control valve 140 sliding within the inner chamber 121, thereby causing the direct-acting damper 120 to perform a damping function, and is filled within the inner chamber 121. The fluid 124 is made of a liquid, gel, or semi-solid substance having a flowability and viscosity according to the specifications of the direct-acting damper 120. In this case, the viscosity of the fluid 124 is selected appropriately according to the specifications of the direct-acting damper 120. In this embodiment, the fluid 124 is made of oil, such as mineral oil or silicone oil. The fluid 124 is indicated by hatching within a dashed circle in FIGS. 3 and 5 (the same applies to FIGS. 9, 12 to 14, and 16 to 20).

[0040] Furthermore, sliding bushings 125a and 125b are fitted onto the outer peripheral surfaces of the socket body 107 and the wall forming body 122 on both sides in the axial direction of the socket body 107 relative to the inner chamber 121. The sliding bushings 125a and 125b are components for smoothly sliding the inner chamber forming body 130 back and forth in the axial direction of the socket body 107, and are made by forming a metal material into an annular shape with an outer diameter slightly larger than the outer diameter of the socket body 107.

[0041] Seal rings 126a, 126b made of an elastic material such as rubber are fitted onto the outer peripheral surfaces of the socket body 107 and the wall forming body 122 on the side opposite to the inner chamber 121 relative to these sliding bushes 125a, 125b. These seal rings 126a, 126b prevent leakage of the fluid 124 in the inner chamber 121 when the inner chamber forming body 130 slides relative to the socket body 107.

[0042] The inner chamber forming body 130 is a component that covers the radial outside of the inner chamber 121 and in which the flow control valve 140 is formed, and is configured by forming a metal material into a cylindrical shape. Specifically, the inner chamber forming body 130 is formed into a cylindrical shape that slidably fits onto the outer peripheral surface of the socket body 107. In this case, the inner chamber forming body 130 is formed to a length that extends beyond the end of the socket body 107 on the rack housing 104 side.

[0043] A flow control valve 140 is formed in a protruding state in the axial center of the inner periphery of this inner chamber forming body 130, and an elastic body holding portion 131 is formed between this flow control valve 140 and the inner periphery of the inner chamber forming body 130. In addition, a dust boot 133 and a dust seal 134 are provided at both axial ends of the inner periphery of the inner chamber forming body 130, respectively.

[0044] The elastic body holding portion 131 is a portion that houses one of the two ends of the return elastic body 132 and is formed in an annular shape between the inner circumferential surface of the inner chamber forming body 130 and the flow control valve 140. The return elastic body 132 is a component that elastically presses the flow control valve 140 toward the left end in the inner chamber 121 as shown in the figure and is made of a metal coil spring. One end (the left end in the figure) of the return elastic body 132 is housed in the elastic body holding portion 131 and elastically presses the inner chamber forming body 130, while the other end (the right end in the figure) elastically presses the outer periphery of the socket body 107 via the sliding bush 125a. In other words, the return elastic body 132 applies elastic force to the inner chamber forming body 130 and the socket body 107 so that the flow control valve 140 (described later) is positioned on the side (the rack housing 104 side) where an external force acts on the linear damper 120.

[0045] The dust boot 133 is a component for preventing dust from entering the interior of the inner chamber forming body 130 from the rack housing 104 side, which is one of both end portions (the left side in the figure) of the inner chamber forming body 130, and is made by forming an elastomer material such as rubber into a cylindrical shape. One end of this dust boot 133 is connected to an end portion of the inner chamber forming body 130, and the other end is connected to the wall forming body 122. Note that the dust boot 133 is not shown in FIG. 2.

[0046] The dust seal 134, like the dust boot 133, is a component that prevents dust from entering the interior of the inner chamber forming body 130 from the stud body 108 side, which is the other (right side in the figure) of both end portions of the inner chamber forming body 130, and is made of an elastomer material such as rubber formed into a ring shape. This dust seal 134 is fitted into a groove cut out in a ring shape at the end portion of the inner chamber forming body 130.

[0047] An accumulator accommodating portion 135 is formed on the outer periphery of the inner chamber forming body 130. The accumulator accommodating portion 135 is a cylindrical portion for liquid-tightly accommodating the accumulator 136, and is formed to protrude from the outer periphery of the inner chamber forming body 130 and extend in the longitudinal direction of the inner chamber forming body 130. One end of this accumulator accommodating portion 135 communicates with the first circulating body 153 side of the inner chamber 121, and the other end is sealed by a plug.

[0048] Accumulator 136 is a device that compensates for volume changes caused by expansion or contraction due to temperature changes of fluid 124 in inner chamber 121. Accumulator 136 is configured by accommodating a piston that slides back and forth within accumulator housing portion 135 while being elastically pressed toward inner chamber 121 by a coil spring.

[0049] The flow control valve 140 is a device for generating a damping force of the direct-acting damper 120 by restricting the flow of the fluid 124 in the inner chamber 121 while allowing it to flow, thereby controlling the flow of the fluid 124. The flow control valve 140 is mainly composed of a valve support 141, a first flow control valve 150, a second flow control valve 160, and a third flow control valve 170.

[0050] The valve support body 141 is the part where the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170 are formed, and is formed in the shape of a flat annular plate that protrudes inward from the inner periphery of the inner chamber forming body 130. The inner periphery of this valve support body 141 is formed into a smooth cylindrical surface so as to slide fluid-tightly against the bottom of the inner chamber 121, and a seal ring 142 made of an elastic material is fitted into it.

[0051] The first flow control valve 150 is a valve that functions as a trigger to generate the maximum damping force when a strong impact force acts on the direct-acting damper 120, and is mainly provided with a second flow body accommodating section 151, a first flow body 153, a second flow body 156, and a separating elastic body 159. The second flow body accommodating section 151 is a section that slidably accommodates the second flow body 156, which will be described later, and is formed in the shape of a cylinder with a bottom that is always open at one end (the right side in the figure) of the valve support body 141.

[0052] In this case, the second flow member accommodating portion 151 is formed so as to always open on the front side of the two side surfaces of the valve support body 141 when the inner chamber forming body 130 slides relative to the socket body 107 against the elastic force of the return elastic body 132. A retaining ring 152 is fitted into a ring-shaped groove formed on the inner circumferential surface of this second flow member accommodating portion 151 near the opening. The retaining ring 152 is a component for preventing the second flow member 156 accommodated in the second flow member accommodating portion 151 from coming off, and is made of a C-shaped metal ring.

[0053] The first circulator 153 is a part for controlling the flow of the fluid 124 in cooperation with the second circulator 156, and is mainly provided with a first flow hole 154 and a first hole diameter regulation portion 155. The first flow hole 154 is a through-hole for allowing the fluid 124 to flow, and is formed in the bottom of the second circulator accommodating portion 151. In this case, the first flow hole 154 is formed in an edge portion of the bottom that is eccentric with respect to the center line of the second circulator accommodating portion 151. That is, the second circulator accommodating portion 151 has a large opening on one side of the inner chamber 121 (the buffer material 123a side) and a small opening on the other side (the buffer material 123b side) due to the first flow hole 154.

[0054] The first hole diameter restriction portion 155 is a portion that blocks the flow of the fluid 124 in the second through hole 157, and is formed in the shape of a wall around the first through hole 154. The first hole diameter restriction portion 155 is formed in a position facing the second through hole 157 so as to completely block the second through hole 157 of the second through body 156 when the second through body 156 comes into contact with the first through body 153. In this embodiment, the first hole diameter restriction portion 155 is formed by the bottom of the second through body accommodating portion 151.

[0055] The second circulator 156 is a component for controlling the flow of the fluid 124 in cooperation with the first circulator 153, and is configured by forming a metal material into a cylindrical shape. In this case, the second circulator 156 is configured with a large diameter portion 156a that slides against the inner circumferential surface of the second circulator accommodating portion 151, and a small diameter portion 156b that is smaller in diameter than the large diameter portion 156a. The second circulator 156 is also formed with a second circulator hole 157 and a second hole diameter restriction portion 158.

[0056] The second communication hole 157 is a through-hole for allowing the fluid 124 to flow, and is composed of a large diameter hole 157a and a small diameter hole 157b that penetrate the second communication body 156. The large diameter hole 157a is formed so as to open to the side surface on the front side when the inner chamber forming body 130 slides and displaces against the elastic force of the return elastic body 132 in the second communication body 156. The small diameter hole 157b extends and opens from the innermost portion of the large diameter hole 157a to the side surface on the rear side when the inner chamber forming body 130 slides and displaces against the elastic force of the return elastic body 132.

[0057] In this case, a flat, annular step portion 157c is formed between the large diameter hole 157a and the small diameter hole 157b. The small diameter hole 157b has a tapered portion 157d formed at its end on the large diameter hole 157a side, with the diameter gradually decreasing toward the back of the small diameter hole 157b. The small diameter hole 157b is formed in a position and size that communicates with the large diameter hole 157a and faces the first hole diameter restriction portion 155 without facing the first through hole 154. That is, the small diameter hole 157b is formed in a position and size that does not overlap the first through hole 154 on the first hole diameter restriction portion 155. In this embodiment, the small diameter hole 157b is formed concentrically with the second flow body 156 and the large diameter hole 157a and has a smaller diameter than the first through hole 154.

[0058] The second hole diameter restriction portion 158 is a portion that blocks the flow of the fluid 124 in the first through hole 154, and is formed in a wall shape around the small diameter hole 157b that constitutes the second through hole 157. Specifically, the second hole diameter restriction portion 158 is formed in a position facing the first through hole 154 so as to block a portion of the first through hole 154 of the first through body 153 when the second through body 156 contacts the first through body 153. In this embodiment, the second hole diameter restriction portion 158 is formed in the shape of a flat annular plate having a size that blocks approximately one-third of the first through hole 154 of the first through body 153 when the second through body 156 contacts the first through body 153.

[0059] The separating elastic body 159 is a component that exerts an elastic force to separate the second circulating body 156 from the first circulating body 153 within the second circulating body accommodating portion 151, and is configured by a metal coil spring. One end (left side in the figure) of this separating elastic body 159 presses the first hole diameter restricting portion 155 (the bottom portion of the second circulating body accommodating portion 151), and the other end (right side in the figure) is fitted onto the outer periphery of the small diameter portion 156b. The elastic force of this separating elastic body 159 is set to a strength corresponding to the magnitude of the external force that is desired to cause the linear damper 120 to generate the maximum damping force. One first circulating body control valve 150 is provided in the valve support body 141.

[0060] The second flow control valve 160 is a valve that blocks the flow of the fluid 124 from the front side to the rear side of the sliding displacement when the inner chamber forming body 130 slides relative to the socket body 107 against the elastic force of the return elastic body 132, and also facilitates the flow of the fluid 124 from the front side to the rear side of the sliding displacement when the inner chamber forming body 130 slides due to the elastic force of the return elastic body 132. That is, the second flow control valve 160 is configured as a one-way valve. The configuration of the one-way valve that constitutes this second flow control valve 160 is well known, so a detailed description will be omitted. One second flow control valve 160 is provided at a position 180° circumferentially from the first flow control valve 150 on the valve support 141.

[0061] The third flow control valve 170 is a valve that restricts and allows the flow of the fluid 124 when the inner chamber forming body 130 slides relative to the socket body 107 against the elastic force of the return elastic body 132 and when the inner chamber forming body 130 slides due to the elastic force of the return elastic body 132. The third flow control valve 170 is configured as a fine through-hole formed in the valve support body 141. In this embodiment, the third flow control valves 170 are formed at two intermediate positions between the first flow control valve 150 and the second flow control valve 160 in the circumferential direction of the valve support body 141.

[0062] (Operation of the steering device 100) Next, the operation of the steering device 100 configured as described above will be described. The steering device 100 is incorporated inside a four-wheeled self-propelled vehicle (not shown) as a mechanism for steering the steered wheels (for example, two front wheels) of the vehicle in the left-right direction. The steering device 100 changes the orientation of the two wheels 112 in response to the operation of the steering wheel 101 by the driver of the self-propelled vehicle, thereby determining the traveling direction of the self-propelled vehicle.

[0063] When such a self-propelled vehicle is being driven, the linear damper 120 in the steering device 100 acts when the rack bar 103 is displaced close to its left-right displacement limit in relation to the pinion gear 102a. In this case, the displacement limit of the rack bar 103 is the left-right steering limit of the wheels 112, and this occurs when the driver of the self-propelled vehicle turns the steering wheel 101 clockwise or counterclockwise close to the rotation limit, or when the wheels 112 collide with an obstacle such as a curb and a large input is applied to the rack bar 103 from the wheel 112 side.

[0064] First, a case will be described in which no external force acts on the direct-acting damper 120 and the direct-acting damper 120 does not operate. As shown in Fig. 3, the direct-acting damper 120 does not operate in a range in which the rack bar 103 does not reach the displacement limit, such as when the wheels 112 of the self-propelled vehicle are not steered to the steering limit, because the inner chamber forming body 130 does not collide with the rack housing 104. In this case, as shown in Fig. 5, the flow control valve 140 of the direct-acting damper 120 is pressed against the wall forming body 122 via the buffer material 123b within the inner chamber 121 by the elastic force of the return elastic body 132. In other words, the inner chamber forming body 130 maintains a state in which it is elastically positioned on the socket body 107 at a position closest to the rack housing 104.

[0065] Furthermore, the first flow control valve 150 maintains a state in which the second flow body 156 is positioned at the farthest position from the first flow body 153 by the elastic force of the separating elastic body 159. In other words, the first flow control valve 150 is in a state in which the fluid 124 can flow.

[0066] Next, a case where an external force acts on the linear damper 120 and the linear damper 120 operates will be described. As shown in Fig. 6, when the rack bar 103 reaches the vicinity of its displacement limit (see the dashed arrow), such as when the wheels 112 of the self-propelled vehicle are steered to the vicinity of the steering limit, the linear damper 120 starts to operate as the end of the inner chamber forming body 130 comes into contact with the rack housing 104. In this case, the linear damper 120 operates in two ways: when the end of the inner chamber forming body 130 comes into contact with the rack housing 104 with a weak force and when the end of the inner chamber forming body 130 comes into contact with the rack housing 104 with a strong force. in There may be cases where contact has occurred.

[0067] First, when the end of the inner chamber forming body 130 comes into contact with the rack housing 104 with a weak force (low speed), the inner chamber forming body 130 slowly slides toward the stud body 108 relative to the socket body 107 (see the dashed arrow) as shown in Fig. 7. That is, the flow control valve 140 is displaced toward the buffer material 123a within the inner chamber 121 against the elastic force of the return elastic body 132. In this case, the fluid 124 flows into the first flow control valve 150 from the large diameter hole 157a side of the second flow hole 157 of the second flow body 156 and flows toward the small diameter hole 157b side.

[0068] However, in this case, the second circulating body 156 is displaced toward the first circulating body 153 and is not pressed against the first circulating body 153 because the force pressing the second circulating body 156 caused by the flow control valve 140 being slowly displaced within the inner chamber 121 is smaller than the elastic force of the separating elastic body 159. Therefore, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows through the second flow hole 157 of the second circulating body 156 and the first flow hole 154 of the first circulating body 153 toward the rear side in the displacement direction with slight flow resistance (see dashed arrows).

[0069] Furthermore, the second flow control valve 160 is a one-way valve that blocks the flow of the fluid 124 from the front side to the rear side in the displacement direction of the flow control valve 140 when the inner chamber forming body 130 slides and displaces against the elastic force of the return elastic body 132, so there is no flow of the fluid 124. Furthermore, the third flow control valve 170 is a valve that allows the fluid 124 to flow in both directions, that is, from the front side to the rear side in the displacement direction of the flow control valve 140, so the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 140 with slight flow resistance.

[0070] Therefore, the flow control valve 140 is displaced toward the buffer material 123a while generating a negligibly small damping force, which causes the inner chamber forming body 130 to slide slowly toward the stud body 108.

[0071] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the end of the inner chamber forming body 130 is separated from the rack housing 104, the inner chamber forming body 130 is displaced to its original position by the elastic force of the return elastic body 132 (see FIG. 5). In this case, the fluid 124 flows into the first flow control valve 150 from the first flow body 153 side and flows toward the second flow body 156 side.

[0072] In this case, the second circulating body 156 returns to its original position farthest from the first circulating body 153 due to the elastic force of the separating elastic body 159 and the pressing force of the fluid 124 flowing from the first circulating body 153. Therefore, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows through the first flow hole 154 of the first circulating body 153 and the second flow hole 157 of the second circulating body 156, respectively, with slight flow resistance to the rear side in the displacement direction.

[0073] Furthermore, since the second flow control valve 160 is a one-way valve that allows the fluid 124 to flow from the front side to the rear side in the displacement direction of the flow control valve 140 when the inner chamber forming body 130 is slidably displaced by the elastic force of the return elastic body 132, the fluid 124 flows with slight flow resistance. Furthermore, since the third flow control valve 170 is a valve that allows the fluid 124 to flow in both directions, that is, from the front side to the rear side in the displacement direction of the flow control valve 140, the fluid 124 flows with slight flow resistance from the front side to the rear side in the displacement direction of the flow control valve 140.

[0074] Therefore, the flow control valve 140 is displaced toward the buffer material 123b while generating a negligibly small damping force, causing the inner chamber forming body 130 to slide and displace toward the rack housing 104 more quickly than the previous displacement speed.

[0075] Next, when the end of the inner chamber forming body 130 comes into contact with the rack housing 104 with a strong force (high speed) (for example, when the driver makes an abrupt turn or the wheel 112 hits a curb), the inner chamber forming body 130 rapidly slides toward the stud body 108 relative to the socket body 107. That is, the flow control valve 140 rapidly displaces toward the buffer material 123a within the inner chamber 121 while resisting the elastic force of the return elastic body 132.

[0076] 8, the force with which the fluid 124 presses against the second circulating body 156 is greater than the elastic force of the separating elastic body 159, and so the first circulating body 150 is displaced toward the first circulating body 153 and pressed against the first circulating body 153. In this case, the pressing force of the fluid 124 acts on the step portion 157c and the tapered portion 157d of the small diameter hole 157b, and the second circulating body 156 begins to displace toward the first circulating body 153, and then the pressing force of the fluid 124 also acts on the end of the large diameter hole 157a, causing the second circulating body 156 to displace toward the first circulating body 153.

[0077] In this case, first hole diameter restricting portion 155 and second hole diameter restricting portion 158 are formed at positions facing second flow hole 157 and first flow hole 154, respectively, and therefore block all of second flow hole 157 and part of first flow hole 154. Therefore, in first flow control valve 150, no flow of fluid 124 occurs when flow control valve 140 is displaced toward stud body 108 (see dashed arrow). In this case, in the same way as above, no flow of fluid 124 occurs in second flow control valve 160.

[0078] Furthermore, because only the third flow control valve 170 allows the flow of fluid 124 in the flow control valve 140, a very large flow resistance is generated in the third flow control valve 170. Therefore, the flow control valve 140 is displaced toward the buffer material 123a while resisting the very large flow resistance caused by the third flow control valve 170. As a result, the inner chamber forming body 130 is slid toward the stud body 108 while generating an extremely large damping force. In other words, the direct-acting damper 120 can attenuate the strong impact that occurs in the rack bar 103.

[0079] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the end of the inner chamber forming body 130 is separated from the rack housing 104, the inner chamber forming body 130 is displaced to its original position by the elastic force of the return elastic body 132, as described above (see FIG. 5). That is, the inner chamber forming body 130 is displaced toward the buffer material 123b while the flow control valve 140 generates an extremely small damping force that can be ignored, and is thereby quickly slid toward the rack housing 104.

[0080] Furthermore, the second circulator 156 separates from the first circulator 153 and returns to its original position due to the elastic force of the separating elastic body 159 and the pressing force of the fluid 124 flowing from the first circulator 153. In this case, the second circulator 156 has the second hole diameter restriction portion 158 formed in a position facing a part of the first circulator hole 154, so that a part of the fluid 124 that has flowed from the first circulator hole 154 into the second circulator accommodating portion 151 can be guided to the second circulator hole 157 side. As described above, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows through the first circulator hole 154 of the first circulator 153 and the second circulator hole 157 of the second circulator 156, respectively, with slight flow resistance.

[0081] As can be understood from the explanation of the operating method above, according to the first embodiment, the linear damper 120 has the socket body 107 as a relative displacement body that penetrates the cylindrically formed inner chamber forming body 130. Therefore, the linear damper 120 can be provided radially outside the rack end 106, which extends axially in the steering device 100, as the object to which the linear damper 120 is to be attached, rather than in the axial direction of the rack end 106, which extends axially. This makes it possible to avoid an increase in the size (mainly length) of the device configuration of the steering device 100 and to expand the types of steering devices that can be attached.

[0082] Second Embodiment Next, a second embodiment of a steering device including a flow control valve and a direct-acting damper according to the present invention will be described with reference to FIGS. 9 to 13. A steering device 200 in this second embodiment differs from the first embodiment in that a direct-acting damper 210, which corresponds to the direct-acting damper 120 in the first embodiment, is mounted to the rack housing 104 rather than the socket body 107. Therefore, the steering device 200 in this second embodiment will be described mainly with respect to the parts that are different from the steering device 200 in the first embodiment, and a description of parts that are common to both embodiments or corresponding parts will be omitted as appropriate. Furthermore, in the description of this second embodiment, components that are similar to those in the first embodiment are denoted by the same reference numerals as in the first embodiment.

[0083] (Configuration of steering device 200) The steering device 200 has a cylindrical linear damper 210 attached to the tip of the cylindrically formed rack housing 104, and a dust boot 201 attached to cover the linear damper 210. The dust boot 201 is a component for preventing the linear damper 210 from being soiled or damaged, and is made by forming an elastomer material such as rubber into a cylindrical shape.

[0084] A rack bar 103 penetrates the inside of the rack housing 104 and passes through the interior of a cylindrical linear damper 210 attached to the tip of the rack housing 104. A rack end 106 is attached to the tip of the rack bar 103. In this case, a socket body 107 attached to the rack bar 103 has an outer periphery that projects in a flange shape from the outer periphery of the rack bar 103, and is formed so as to face the end of the relative displacement body 230.

[0085] The linear damper 210 includes an inner chamber forming body 211. The inner chamber forming body 211 is a component that forms an inner chamber 217 and is used to attach the linear damper 210 to the rack housing 104, and is configured by forming a metal material into a cylindrical shape. That is, the inner chamber forming body 211 corresponds to the inner chamber forming body 130 in the first embodiment. This inner chamber forming body 211 has a male thread portion 211a formed at one end (the left side in the figure) of its outer periphery for threadably fitting into the rack housing 104, and a fuel filler port 212 and an accumulator accommodating portion 213 formed at the other end (the right side in the figure), respectively.

[0086] The fuel filler port 212 is a flow passage for injecting or discharging the fluid 124 into the internal chamber 217, and is closed by a plug so as to be freely opened and closed. The accumulator housing portion 213 and the accumulator 214 correspond to the accumulator housing portion 135 and the accumulator 136 in the first embodiment, respectively. Inside the internal chamber forming body 211, wall forming bodies 215 and 216 are threadedly fitted to both ends, and a cylindrical internal chamber 217 is formed between these two wall forming bodies 215 and 216.

[0087] The wall forming bodies 215, 216 are components for forming the wall portions on both the left and right sides of the inner chamber 217 in the drawing, and are configured by forming a metal material into an annular shape. In other words, the wall forming bodies 215, 216 correspond to the wall forming body 122 in the first embodiment. Therefore, the inner chamber 217 is formed in the shape of an annular cylinder extending in the axial direction between the inner chamber forming body 211 and a relative displacement body 230, which will be described later, inside the inner chamber forming body 211. Of these wall forming bodies 215, 216, the wall forming body 216 on the intermediate connector 105 side has a return elastic body 218 fitted to its outer periphery.

[0088] The return elastic body 218 is a component for elastically pressing the flow control valve 240 toward the right end in the illustration within the inner chamber 217, and is configured by a metal coil spring. That is, the return elastic body 218 corresponds to the return elastic body 132 in the first embodiment. One end (the left end in the illustration) of this return elastic body 218 elastically presses the wall forming body 216, and the other end (the right end in the illustration) elastically presses the relative displacement body 230 via the receiving plate 218a. That is, the return elastic body 218 applies elastic forces to the inner chamber forming body 211 and the socket body 107 so that the flow control valve 240 is positioned on the side where an external force acts on the direct-acting damper 210 (the side of the ball holding portion 107a).

[0089] In addition, the wall forming bodies 215, 216 are provided with cushioning materials 221a, 221b, sliding bushings 222a, 222b, seal rings 223a, 223b and dust seals 224a, 224b, which correspond to the cushioning materials 123a, 123b, sliding bushings 125a, 125b, seal rings 126a, 126b and dust seal 134 in the first embodiment, respectively.

[0090] The relative displacement body 230 is a component that covers the radially inner side of the inner chamber 217 and in which the flow control valve 240 is formed, and is configured by forming a metal material into a cylindrical shape. That is, the relative displacement body 230 corresponds to the socket body 107 in the first embodiment. The relative displacement body 230 is formed into a cylindrical shape that slidably fits onto the inner circumferential surfaces of the wall formation bodies 215, 216 via sliding bushings 222a, 222b. In this case, the relative displacement body 230 is formed to a length that extends beyond each end of the wall formation bodies 215, 216. The inner diameter of the relative displacement body 230 is formed to be large enough to allow the rack bar 103 to pass through.

[0091] The aforementioned receiving plate 218a is fixedly attached to one end (the right side in the figure) of the outer periphery of this relative displacement body 230, and a fixed sleeve 231 and a flow control valve 240 are attached from the other end (the left side in the figure) to the center in the axial direction. The fixed sleeve 231 is a component for pressing and fixing the flow control valve 240, which fits into a small diameter portion formed on the outer periphery of the relative displacement body 230, against a large diameter portion formed on the outer periphery of the relative displacement body 230, and is made of a cylindrical metal material. The fixed sleeve 231 is fitted into the outer periphery of the relative displacement body 230 and assembled integrally therewith, and slides against the wall formation body 215 via a sliding bush 222a.

[0092] The flow control valve 240 is a device for generating a damping force of the direct-acting damper 210 by restricting the flow of the fluid 124 in the inner chamber 217 while allowing it to flow, thereby controlling the flow of the fluid 124, and corresponds to the flow control valve 140 in the first embodiment. This flow control valve 240 is mainly configured to include a valve support 241, a first flow control valve 150, a second flow control valve 160, and a third flow control valve 170.

[0093] The valve support body 241 is a component on which the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170 are respectively formed, and is configured by forming a metal material into a flat, annular plate. That is, the valve support body 241 is configured as a separate body from the relative displacement body 230, and is attached integrally to the relative displacement body 230 by a fixing sleeve 231. A seal ring 242 corresponding to the seal ring 142 in the first embodiment is fitted onto the outer periphery of this valve support body 241.

[0094] The first flow control valve 150, the second flow control valve 160, and the third flow control valve 170 are configured in the same manner as in the above embodiment, and therefore a description thereof will be omitted. The flow control valve 240 is attached to the outer periphery of the relative displacement body 230 with the large diameter portion 156a of the second flow body 156 of the first flow control valve 150 facing the cushioning material 221a side (left side in the figure).

[0095] (Operation of the steering device 200) Next, we will explain the operation of the steering device 200 configured as above. In the steering device 200, similar to the steering device 100 in the above embodiment, the linear damper 210 acts when the rack bar 103 is displaced close to the left and right displacement limits in relation to the pinion gear 102a.

[0096] Specifically, the direct-acting damper 210 does not operate in a range where the rack bar 103 does not reach the vicinity of the displacement limit, such as when the wheels 112 of the self-propelled vehicle are not steered to the vicinity of the steering limit, because the socket body 107 does not collide with the relative displacement body 230 (see FIG. 9). In this case, the flow control valve 240 of the direct-acting damper 210 is pressed against the wall formation body 216 via the buffer material 221b by the elastic force of the return elastic body 218 within the inner chamber 217. In other words, the relative displacement body 230 maintains a state in which it is elastically positioned at a position closest to the socket body 107 within the inner chamber 217.

[0097] Furthermore, the first flow control valve 150 maintains a state in which the second flow body 156 is positioned at the farthest position from the first flow body 153 by the elastic force of the separating elastic body 159. In other words, the first flow control valve 150 is in a state in which the fluid 124 can flow.

[0098] Next, as shown in FIG. 11, when the rack bar 103 reaches near its displacement limit, such as when the wheels 112 of the self-propelled vehicle are steered near their steering limit, the socket body 107 comes into contact with the end of the relative displacement body 230 and the linear damper 210 begins to operate.

[0099] First, when the socket body 107 comes into contact with the end of the relative displacement body 230 with a weak force (low speed), the relative displacement body 230 slowly slides and displaces toward the rack housing 104 with respect to the inner chamber forming body 211, as shown in Fig. 12. That is, the flow control valve 240 displaces toward the buffer material 221a side (left side in the figure) within the inner chamber 217 against the elastic force of the return elastic body 218. In this case, the fluid 124 flows into the first flow control valve 150 from the large diameter hole 157a side of the second flow hole 157 of the second flow body 156 and flows toward the small diameter hole 157b side.

[0100] However, in this case, the second circulating body 156 is displaced toward the first circulating body 153 and is not pressed against the first circulating body 153 because the force pressing the second circulating body 156 caused by the flow control valve 240 being slowly displaced within the inner chamber 217 is smaller than the elastic force of the separating elastic body 159. Therefore, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows through the second flow hole 157 of the second circulating body 156 and the first flow hole 154 of the first circulating body 153, respectively, with slight flow resistance toward the rear side in the displacement direction.

[0101] Furthermore, the second flow control valve 160 is a one-way valve that prevents the flow of the fluid 124 from the front side to the rear side in the displacement direction of the flow control valve 240 when the relative displacement body 230 slides and displaces against the elastic force of the return elastic body 218, and therefore there is no flow of the fluid 124. Furthermore, the third flow control valve 170 is a valve that allows the fluid 124 to flow in both directions, that is, forward and rearward, in the displacement direction of the flow control valve 240, and therefore the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 240 with slight flow resistance.

[0102] Therefore, the flow control valve 240 is displaced toward the buffer material 123a while generating a negligibly small damping force, whereby the relative displacement body 230 is slowly slid toward the rack housing 104.

[0103] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the end of the relative displacement body 230 is separated from the socket body 107, the relative displacement body 230 is displaced to its original position by the elastic force of the return elastic body 218, as in the first embodiment (see FIG. 9). That is, the flow control valve 240 is displaced toward the buffer material 221b while generating an extremely small damping force that can be ignored. As a result, the relative displacement body 230 slides and displaces toward the socket body 107 more quickly than the previous displacement speed.

[0104] Next, when the socket body 107 comes into contact with the end of the relative displacement body 230 with a strong force (high speed), the relative displacement body 230 is rapidly slid and displaced toward the rack housing 104 side relative to the inner chamber forming body 211, as shown in Fig. 13. That is, the flow control valve 240 is rapidly displaced toward the buffer material 221a side within the inner chamber 217 while resisting the elastic force of the return elastic body 218.

[0105] In this case, the force with which the fluid 124 presses against the second flow body 156 is greater than the elastic force of the separating elastic body 159, so the first flow control valve 150 is displaced toward the first flow body 153 and pressed against the first flow body 153. Furthermore, in this case, the first hole diameter restricting portion 155 and the second hole diameter restricting portion 158 are formed in positions facing the second flow hole 157 and the first flow hole 154, respectively, and therefore block all of the second flow hole 157 and part of the first flow hole 154, respectively. Therefore, in the first flow control valve 150, no flow of the fluid 124 occurs when the flow control valve 240 is displaced toward the rack housing 104 (see the dashed arrow). Furthermore, in this case, no flow of the fluid 124 occurs in the second flow control valve 160, as described above.

[0106] Furthermore, because only the third flow control valve 170 allows the fluid 124 to flow through the flow control valve 240, a very large flow resistance is generated in the third flow control valve 170. Therefore, the flow control valve 240 is displaced toward the buffer material 221a while resisting the very large flow resistance caused by the third flow control valve 170. As a result, the relative displacement body 230 is slidably displaced toward the rack housing 104 while generating an extremely large damping force. In other words, the direct-acting damper 210 can attenuate the strong impact that occurs in the rack bar 103.

[0107] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the end of the relative displacement body 230 is separated from the socket body 107, the relative displacement body 230 is displaced to its original position by the elastic force of the return elastic body 218, as described above (see FIG. 9). That is, the relative displacement body 230 is displaced toward the buffer material 221b while the flow control valve 240 generates an extremely small damping force that can be ignored, and is thereby quickly slid toward the socket body 107.

[0108] Furthermore, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the present invention. In the description of each modification, the same reference numerals will be used to designate the same parts as those in the above-described embodiments, and redundant description will be omitted.

[0109] For example, in each of the above embodiments, the direct-acting dampers 120, 210 are configured with the flow control valves 140, 240 provided inside the inner chambers 121, 217. This allows the direct-acting dampers 120, 210 to have a more compact device configuration by providing the flow control valves 140, 240 inside the inner chambers 121, 217. However, the direct-acting dampers 120, 210 may also be configured with part or all of the flow control valves 140, 240 provided outside the inner chambers 121, 217.

[0110] 14 and 15 show a direct-acting damper 300 in which a first flow control valve 150 is provided in the inner chamber forming body 211 of the direct-acting damper 210 according to the second embodiment. This direct-acting damper 300 has a bypass flow path 301 formed inside the inner chamber forming body 211, and is provided with the first flow control valve 150, which forms part of the flow control valve 310 and is connected to the bypass flow path 301 on the outer periphery of the inner chamber forming body 211. The bypass flow path 301 is a flow path for the fluid 124 that connects one end side and the other end side of the inner chamber 217 in the axial direction, with the flow control valve 310 as a boundary.

[0111] The flow control valve 310 is configured to include a second flow control valve 160 and a third flow control valve 170, which are obtained by moving only the first flow control valve 150 from the flow control valve 240 in the second embodiment to the inner chamber forming body 211. The first flow control valve 150 controls whether or not the fluid 124 flowing through the bypass flow path 301 is allowed to flow.

[0112] In this case, the first flow control valve 150 has a second flow body accommodating section 151 formed inside the inner chamber forming body 211 in a state in which the second flow body accommodating section 151 is in communication with the inner chamber 217, and a second flow body 156 and a separating elastic body 159 are accommodated in the second flow body accommodating section 151. An eccentric ring body constituting the first flow body 153 (a component having a through hole functioning as the first flow hole 154 formed at a position eccentric from the center of the disk body functioning as the first hole diameter restricting section 155) is fitted into the side of the second flow body accommodating section 151 opposite the inner chamber 217 side, and is in communication with the bypass flow path 301 via the first flow body 153. In addition, the inner chamber forming body 211 is formed with a bypass flow path 301 extending to a portion opposing the second flow body accommodating section 151 across the bypass flow path 301 so as to communicate with the outside of the inner chamber forming body 211, and this extended bypass flow path 301 is blocked by a plug 302.

[0113] That is, the direct-acting damper 300 is configured such that the second flow control valve 160 and the third flow control valve 170, which are parts of the flow control valve 310, are provided inside the inner chamber 217, and the first flow control valve 150, which is the other part, is provided outside the inner chamber 217. The direct-acting damper 300 configured in this manner operates in the same manner as the direct-acting damper 210 in the second embodiment. Note that the rack bar 103 and the rack housing 104 are not shown in FIG. 14.

[0114] In this way, the direct-acting damper 300 can ensure a large capacity of the inner chamber 217 by providing part or all of the flow control valve 310 outside at least the inner chamber 217. Furthermore, the direct-acting damper 300 can improve maintainability by removing the plug 302 in the inner chamber forming body 211 to expose the first flow control valve 150.

[0115] Furthermore, in each of the above embodiments, the direct-acting dampers 120, 210, 300 are configured to include the return elastic bodies 132, 218, respectively. However, when it is not necessary to constantly press the flow control valves 140, 240, 310 to one side of the inner chambers 121, 217 (the side where an external force acts on the direct-acting dampers 120, 210, 300), the return elastic bodies 132, 218 can be omitted.

[0116] In the first embodiment, the socket body 107 serving as the relative displacement body is formed in an axial shape. However, the socket body 107 serving as the relative displacement body can also be formed in a cylindrical shape, as shown in Fig. 16. In this case, the steering device 100 can couple the rack bar 103 and the socket body 107 by threaded engagement by forming a male thread at the tip of the rack bar 103 and a female thread in the through-hole of the socket body 107.

[0117] Furthermore, in each of the above embodiments, the first flow control valve 150 is configured so that the second hole diameter restriction portion 158 of the second flow body 156 blocks a portion of the first flow hole 154 of the first flow body 153, and the first hole diameter restriction portion 155 of the first flow body 153 blocks all of the second flow hole 157 of the second flow body 156. However, it is sufficient that the first flow control valve 150 is configured to block at least a portion of at least one of the first flow hole 154 and the second flow hole 157.

[0118] Therefore, the first flow control valve 150 can be configured to completely block both the first flow hole 154 and the second flow hole 157, for example, as shown in Fig. 17. The first flow control valve 150 can also be configured to partially block both the first flow hole 154 and the second flow hole 157. In this case, the first flow control valve 150 can also be configured, for example, as shown in Fig. 18, so that when the second flow body 156 comes into close contact with the first flow body 153, a portion of the first flow hole 154 and a portion of the second flow hole 157 overlap with each other, thereby ensuring the flow of the fluid 124. In this way, the flow control valves 140, 240 can be configured without the third flow control valve 170.

[0119] Furthermore, the first flow control valve 150 can also be configured to completely block one of the first flow hole 154 and the second flow hole 157 while not blocking the other at all. For example, as shown in FIG. 19 , the first flow control valve 150 can be formed with a first hole diameter restricting portion 155 that protrudes in a columnar shape toward the small diameter hole 157b (second flow hole 157) at a portion facing the small diameter hole 157b at the bottom of the second flow body accommodating portion 151. In this case, the second hole diameter restricting portion 158 of the second flow body 156 is omitted. This allows the first flow control valve 150 to block only the second flow hole 157 by the second flow body 156 hitting the first hole diameter restricting portion 155.

[0120] 20 and 21, the first flow control valve 150 can be configured such that a second hole diameter restricting portion 158 protruding in a columnar shape toward the first flow hole 154 is provided in a portion of the second flow body 156 facing the first flow hole 154, thereby blocking only the first flow hole 154. In this case, the first hole diameter restricting portion 155 in the first flow body 153 is omitted. In these cases, the columnar first hole diameter restricting portion 155 and / or second hole diameter restricting portion 158 can be configured to be inserted into the small diameter hole 157b (second flow hole 157) and / or the first flow hole 154 to block the respective holes.

[0121] In each of the above embodiments, the second communication hole 157 is configured with two holes, the large-diameter hole 157a and the small-diameter hole 157b. However, the second communication hole 157 may be configured with a single hole, the large-diameter hole 157a or the small-diameter hole 157b, or may be configured with three or more holes with different inner diameters. The second communication hole 157 has a tapered portion 157d formed at the opening of the small-diameter hole 157b on the side opposite the first communication body 153. This allows the second communication body 156 to facilitate the flow of the fluid 124 into the second communication hole 157, thereby stabilizing the operation of the first communication control valve 150. Furthermore, the first communication control valve 150 allows the fluid 124 to easily flow into the second communication hole 157, thereby increasing the flow rate. Therefore, the tapered portion 157d receives a strong pressing force from the fluid 124, which allows the second communication body 156 to be easily displaced toward the first communication body 153. However, it goes without saying that the tapered shape may be omitted and the second through holes 157 may be formed in a straight shape. The first through holes 154 may also be configured with a plurality of different holes, and the openings of the holes may be tapered.

[0122] Furthermore, in each of the above embodiments, the flow control valves 140, 240, 310 are configured to include a plurality of flow control valves, such as the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170. Here, the second flow control valve 160 can improve the displacement speed during return displacement of the flow control valves 140, 240. Furthermore, the third flow control valve 170 can ensure the flow of the fluid 124 even in a state in which the second flow body 156 is in close contact with the first flow body 153 and the flow of the fluid 124 is completely blocked.

[0123] However, the flow control valves 140, 240, 310 can be configured to include at least one of the first flow control valve 150 and the third flow control valve 170 depending on the specifications of the direct-acting dampers 120, 210, 300. In these cases, the second flow control valve 160 may or may not be included depending on the specifications of the direct-acting dampers 120, 210, 300.

[0124] Furthermore, in each of the above embodiments, the linear dampers 120, 210, 300 are applied to the steering devices 100, 200. However, the linear dampers 120, 210, 300 can be attached to devices or equipment other than the steering devices 100, 200, specifically, suspension mechanisms, seat tilting mechanisms, door opening / closing mechanisms, mechanical devices other than self-propelled vehicles, electrical devices, equipment, or furniture. [Explanation of symbols]

[0125] 100...Steering device, 101...Steering wheel, 102...Steering shaft, 102a...Pinion gear, 103...Rack bar, 103a...Rack gear, 104...Rack housing, 105...Intermediate connecting body, 106...Rack end, 107...Socket body (relative displacement body), 107a...Ball holding portion, 107b...Male thread portion, 108...Stud body, 108a...Ball portion, 110...tie rod, 111...knuckle arm, 112...wheel, 120... Linear damper, 121... Inner chamber, 122... Wall forming body, 123a, 123b... Buffer material, 124... Fluid, 125a, 125b... Sliding bush, 126a, 126b... Seal ring, 130...inner chamber forming body, 131...elastic body holding portion, 132...returning elastic body, 133...dust boot, 134...dust seal, 135...accumulator accommodating portion, 136...accumulator, 140...flow control valve, 141...valve support, 142...seal ring, 150...first flow control valve, 151...second flow body accommodating portion, 152...preventive ring, 153...first flow body, 154...first flow hole, 155...first hole diameter regulating portion, 156...second flow body, 156a...large diameter portion, 156b...small diameter portion, 157...second flow hole, 157a...large diameter hole, 157b...small diameter hole, 157c...step portion, 157d...tapered portion, 158...second hole diameter regulating portion, 159...separating elastic body, 160...second flow control valve, 170...Third flow control valve, 200...Steering device, 201...Dust boot, 210... Linear damper, 211... Inner chamber forming body, 211a... Male thread portion, 212... Oil filler port, 213... Accumulator accommodating portion, 214... Accumulator, 215, 216... Wall forming body, 217... Inner chamber, 218... Return elastic body, 218a... Receiving plate, 221a, 221b... Cushioning material, 222a, 222b... Sliding bush, 223a, 223b... Seal ring, 224a, 224b... Dust seal, 230... relative displacement body, 231... fixed sleeve, 240...flow control valve, 241...valve support, 242...seal ring, 300...direct acting damper, 301...bypass flow path, 302...plug, 310...flow control valve.

Claims

1. A linear damper includes an inner chamber forming body having an inner chamber for liquid-tightly accommodating a fluid, and attenuates an external force applied to the fluid by restricting the flow of the fluid, a rod-shaped relative displacement body that is displaced relative to the inner chamber forming body; a flow control valve provided in at least one of the inner chamber forming body and the relative displacement body, which controls the flow of the fluid by restricting the flow of the fluid while allowing it to flow; a return elastic body that applies elastic force, The inner chamber is formed in an annular cylindrical shape outside the relative displacement body, The flow control valve is formed on a ring-shaped valve support that fits into the annular cylindrical inner chamber, a first flow body having a first flow hole through which the fluid flows; a second flow body disposed opposite the first flow body and having a second flow hole through which the fluid flows; a separating elastic body that exerts an elastic force to separate the first circulating body and the second circulating body from each other at positions where they contact each other, at least one of the first flow body and the second flow body includes a hole diameter restricting portion that closes at least a portion of at least one of the second flow hole and the first flow hole when the first flow body and the second flow body come into contact with each other, The returning elastic body is an elastic force is applied to one of the inner chamber forming body and the relative displacement body to cause the fluid to flow from the first flow body side to the second flow body side in the flow control valve, and the elastic force is applied to one of the inner chamber forming body and the relative displacement body to displace the one relative to the other, The inner chamber forming body is A direct-acting damper characterized in that it is formed in a cylindrical shape that is slidably fitted into the relative displacement body and is displaced relative to the inner chamber together with the flow control valve via the flow control valve.

2. a steering shaft formed in a rod-like shape and rotated by operation of a steering wheel; a rack bar formed in a rod-like shape, which converts the rotational motion of the steering shaft into a reciprocating motion in the axial direction and transmits the motion; an intermediate connector connected to each end of the rack bar and directly or indirectly connecting a wheel to be steered to each end of the rack bar; A steering device comprising a rack housing that covers the rack bar, a direct acting damper that includes an inner chamber forming body having an inner chamber that fluid-tightly accommodates a fluid and attenuates an external force applied to the fluid by restricting the flow of the fluid; the linear damper is provided between the rack housing and the rack bar or the intermediate connecting body to attenuate impact from the wheel, a relative displacement body that is displaced relative to the inner chamber forming body; a flow control valve provided in at least one of the inner chamber forming body and the relative displacement body, which controls the flow of the fluid by restricting the flow of the fluid while allowing it to flow, The flow control valve is a first flow body having a first flow hole through which the fluid flows; a second flow body disposed opposite the first flow body and having a second flow hole through which the fluid flows; a separating elastic body that exerts an elastic force to separate the first circulating body and the second circulating body from each other at positions where they contact each other, At least one of the first circulating medium and the second circulating medium is A steering device characterized by comprising a hole diameter regulating portion that blocks at least a portion of at least one of the second flow hole and the first flow hole when the first flow body and the second flow body come into contact with each other.

3. In the steering device described in claim 2, The hole diameter restricting portion is A steering device, characterized in that the steering wheel is provided on only one of the first circulating body and the second circulating body.

4. In the steering device described in claim 2, The hole diameter restricting portion is A steering device characterized in that a spring is provided in both the first circulating body and the second circulating body.

5. A steering device according to any one of claims 2 to 4, The hole diameter restricting portion is A steering device characterized in that the second through hole and the first through hole are formed so as to completely block at least one of the first through hole and the second through hole.

6. A steering device according to any one of claims 2 to 5, The flow control valve further comprises: a second circulating body accommodating section for slidably accommodating the second circulating body on the second circulating body side relative to the first circulating body; The separating elastic body is A steering device, characterized in that it is provided between the first circulating body and the second circulating body in the second circulating body accommodating portion.

7. A steering device according to any one of claims 2 to 6, The second circulation medium is A steering device characterized in that the opening of the second flow hole on the opposite side to the first flow body is formed in a tapered shape such that the size of the hole decreases from the opening side toward the back side.

8. A steering device according to any one of claims 2 to 7, The flow control valve further comprises: a second flow control valve configured as a one-way valve for circulating the fluid through a flow path separate from the first flow body and the second flow body; The second flow control valve is A steering device characterized in that the flow of the fluid from the first circulating body side toward the second circulating body side is permitted while the flow of the fluid from the second circulating body side toward the first circulating body side is prevented.

9. In the steering device according to any one of claims 2 to 8, the flow control valve further comprises: a third flow control valve configured to restrict the flow of the fluid while allowing the fluid to flow through a flow path separate from the first flow body and the second flow body; The third flow control valve is A steering device characterized in that the fluid is circulated while being restricted in flow between the first circulating body side and the second circulating body side.

10. A steering device according to any one of claims 2 to 9, The linear damper further comprises: a return elastic body that applies an elastic force to cause the fluid to flow from the first flow body side to the second flow body side in the flow control valve, The returning elastic body is A steering device characterized in that the elastic force is applied to one of the inner chamber forming body and the relative displacement body to displace the one relative to the other.

11. 11. The steering device according to claim 10, The relative displacement body is formed in a rod shape, The inner chamber is formed in an annular cylindrical shape outside the relative displacement body, The flow control valve is formed on a ring-shaped valve support that fits into the annular cylindrical inner chamber, The inner chamber forming body is a steering device characterized in that the steering device is formed in a cylindrical shape so as to be slidably fitted into the relative displacement body, and is displaced relative to the inner chamber together with the flow control valve via the flow control valve.

12. 11. The steering device according to claim 10, The inner chamber forming body is formed in a cylindrical shape, The inner chamber is formed in a circular cylindrical shape inside the inner chamber forming body, The flow control valve is formed on a ring-shaped valve support that fits into the annular cylindrical inner chamber, The relative displacement body is a steering device formed in a rod shape that is slidably fitted into the inner chamber forming body and that is displaced integrally with the flow control valve relative to the inner chamber via the valve support;

13. In the steering device described in claim 11, the relative displacement body is formed on the intermediate connector, The inner chamber forming body is A steering device characterized in that the rack bar is formed at a position where it comes into contact with or moves away from the rack housing due to the reciprocating motion of the rack bar.

14. In the steering device described in claim 12, The inner chamber forming body is formed at an end of the rack housing, The relative displacement body is A steering device characterized in that the rack bar or the intermediate connector passes through the interior thereof, and the rack bar or the intermediate connector is formed at a position where it comes into contact with or separates from the rack bar due to the reciprocating motion of the rack bar.

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