Linear damper and steering device

Abstract

Provided are a direct action damper by which it is possible to avoid increasing the size of the structure of the target device on which the damper is mounted, and which can be mounted on a wider variety of targets, and a steering device to which the direct action damper is provided. A steering device 100 is provided with a direct action damper 120 between a rack bar 103 and a rack end 106. The direct action damper 120 has an inner chamber 121 formed between the inside of an inner-chamber-forming body 130 and a socket main body 107. The socket main body 107 is a shaft-shaped component that forms the rack end 106 of the steering device 100, and is slidably fitted into the inner-chamber-forming body 130. The inner-chamber-forming body 130 is cylindrically formed and has a ring-shaped circulation control valve 140 formed in the inner circumference thereof. The circulation control valve 140 is constituted by a first circulation control valve 150, a second circulation control valve 160, and a third circulation control valve 170.　FIG. 3

Description

Technical Field

[0001] The present invention relates to a linear damper that attenuates kinetic energy in linear motion and a steering device including the linear damper.

Background Art

[0002] Conventionally, there has been a linear damper that attenuates kinetic energy in linear motion. For example, Patent Document 1 below discloses a linear damper in which a piston rod reciprocates in a linear direction within a cylindrical cylinder tube filled with fluid oil.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

[0004] However, in the linear damper disclosed in Patent Document 1 above, since it is attached to the tip of a component that reciprocates in a linear direction in the object to be attached, there is a problem that the device configuration of the object to be attached is enlarged (mainly elongated) and the attachable objects to be attached are limited.

[0005] The present invention has been made to address the above problems, and an object thereof is to provide a linear damper that can avoid enlargement (mainly elongation) of the device configuration of the object to be attached and can expand the types of attachable objects to be attached, and a steering device including the linear damper.

[0006] To achieve the above object, the present invention is characterized in that in a linear damper that includes an inner chamber forming body having an inner chamber that hermetically contains a fluid and attenuates an external force received by the fluid by restricting the flow of the same fluid, a relative displacement body that relatively displaces with respect to the inner chamber forming body, and a flow control valve provided on at least one of the inner chamber forming body and the relative displacement body that allows the fluid to flow while restricting the flow of the fluid. The inner chamber forming body is formed in a cylindrical shape and forms an inner chamber inside the cylindrical portion. The relative displacement body penetrates through the inner chamber forming body and with both ends exposed outside the inner chamber forming body is slidably fitted to the inner chamber forming body.

[0007] According to the characteristics of the present invention configured as described above, in the linear damper, since the relative displacement body is provided in a state of penetrating through the cylindrically formed inner chamber forming body, the linear damper can be provided outside the axially extending portion of the object to which the linear damper is attached, rather than in the axial direction of the portion, avoiding an increase in the size (mainly, elongation) of the device configuration of the object to be attached and expanding the types of objects to which the linear damper can be attached.

[0008] Another characteristic of the present invention is that in the linear damper, further, a return elastic body that applies an elastic force to at least one of the inner chamber forming body and the relative displacement body so that the flow control valve is located on the side where an external force acts on the linear damper is provided.

[0009] According to another characteristic of the present invention configured as described above, in the linear damper, the return elastic body applies an elastic force to one of the inner chamber forming body and the relative displacement body, and elastically displaces the flow control valve to one end side in the relative displacement range. As a result, when no external force that relatively displaces the inner chamber forming body and the relative displacement body acts, the linear damper according to the present invention always positions the relative displacement body at one end side in the relative displacement region, that is, the operation start position for the flow control valve to exhibit the damping function, and can maximize the stroke of the relative displacement body.

[0010] In addition, another feature of the present invention is that in the linear damper, the relative displacement body is formed in a cylindrical shape.

[0011] According to another feature of the present invention configured as described above, since the relative displacement body of the linear damper is formed in a cylindrical shape, the linear damper can be provided in a state where the axially extending portion of the object to which the linear damper is attached penetrates into the relative displacement body, avoiding an increase in the size (mainly elongation) of the device configuration of the object to be attached and expanding the types of objects to which the linear damper can be attached.

[0012] In addition, another feature of the present invention is that in the linear damper, the flow control valve is provided at least in the inner chamber forming body.

[0013] According to another feature of the present invention configured as described above, in the linear damper, since the flow control valve is provided at least in the inner chamber forming body, the configuration of the relative displacement body can be simplified.

[0014] In addition, another feature of the present invention is that in the linear damper, the flow control valve is provided at least in the relative displacement body.

[0015] According to another feature of the present invention configured as described above, in the linear damper, since the flow control valve is provided at least in the relative displacement body, the configuration of the inner chamber forming body can be simplified, and since the flow control valve is provided on the outer peripheral portion of the relative displacement body, maintenance can be easily performed by removing the relative displacement body from the inner chamber forming body.

[0016] In addition, another feature of the present invention is that in the linear damper, the flow control valve is provided at least outside the inner chamber.

[0017] According to another feature of the present invention configured as described above, in the linear damper, since the flow control valve is provided at least outside the inner chamber, a large inner chamber capacity can be ensured and the maintainability of the flow control valve can be improved.

[0018] Moreover, the present invention can be implemented not only as an invention of a direct-acting damper, but also as an invention of a steering device including this direct-acting damper.

[0019] Specifically, in a steering device including a steering shaft that extends in a rod shape and rotates by operation of a steering wheel, a rack bar that extends in a rod shape and converts the rotational movement of the steering shaft into a reciprocating movement in the axial direction and transmits it, intermediate connectors that are respectively connected to both ends of the rack bar and directly or indirectly connect wheels to be steered to the respective both ends, and a rack housing that covers the rack bar, a direct-acting damper according to any one of claims 1 to 6 is provided, and the direct-acting damper is provided between the rack housing and the rack bar or the intermediate connector and is configured to attenuate an impact from the wheels. According to this, the steering device according to the present invention can be expected to have the same effects as the above-described direct-acting damper.

[0020] In this case, in the steering device, the relative displacement body is formed on the intermediate connector, and the inner chamber forming body is formed at a position where it comes into contact with or separates from the rack housing by the reciprocating movement of the rack bar.

[0021] According to this, in the steering device according to the present invention, the relative displacement body is formed at the rack end that movably connects the tie rod to the rack bar, and the inner chamber forming body is formed at a position where it comes into contact with or separates from the rack housing by the reciprocating movement of the rack bar linear motion Since the damper is provided on an intermediate connector such as a tie rod or a rack end, it is possible to facilitate maintenance or replacement of the direct-acting damper.

[0022] Also, in this case, in the steering device, the inner chamber forming body is formed at the end of the rack housing, the relative displacement body has a rack bar or an intermediate connecting body penetrating therethrough, and is formed at a position where the rack bar or the intermediate connecting body comes into contact with or separates from each other by the reciprocating motion of the rack bar.

[0023] 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 a rack bar or an intermediate connecting body (such as a tie rod or a rack end) penetrates through the relative displacement body, and the relative displacement body is formed so that the rack bar or the tie rod comes into contact with or separates from each other by the reciprocating motion of the rack bar. Thus, in the steering device according to the present invention, since the direct-acting damper is provided in the rack housing, intermediate connector (such as a tie rod or a rack end) can be reduced in weight.

Brief Description of the Drawings

[0024]

Figure 1

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Embodiment for Carrying out the Invention

[0025] <First Embodiment> Hereinafter, a first embodiment, which is an embodiment of a direct-acting damper according to the present invention and a steering device equipped with this direct-acting damper, will be described with reference to the drawings. FIG. 1 is an explanatory view schematically showing an overview of the overall configuration of a steering device 100 according to the first embodiment of the present invention. Further, FIG. 2 is a perspective view showing an overview of the external appearance configuration of a direct-acting damper 120 according to the first embodiment of the present invention that constitutes the steering device 100 shown in FIG. 1. Further, FIG. 3 is a cross-sectional view showing an overview of the internal configuration of the direct-acting damper 120 shown in FIG. 2. Further, FIG. 4 is a cross-sectional view showing an inner chamber forming body 130 and a socket body 107 as seen from the 4-4 line shown in FIG. 3. Further, FIG. 5 is a partially enlarged view showing in detail the structure within the broken-line circle 5 in the direct-acting damper 120 shown in FIG. 3.

[0026] This steering device 100 is a mechanical device for steering two front wheels (or rear wheels) of a four-wheel self-propelled vehicle (not shown) in the left-right direction respectively.

[0027] (Configuration of Steering Device 100) The steering device 100 includes a steering wheel 101. The steering wheel 101 is an operating element (that is, a steering wheel) for a driver of a self-propelled vehicle to manually operate the traveling direction, and is formed in an annular shape from a resin material or a metal material. A steering shaft 102 is connected to this steering wheel 101.

[0028] The steering shaft 102 is formed in a rod shape and rotates around the axis in response to the clockwise or counterclockwise rotation operation of the steering wheel 101. It is composed of one or a plurality of metal rods connected via a universal joint or the like. One end of this steering shaft 102 is connected to the steering wheel 101, and a pinion gear 102a is formed at the other end and connected to the rack bar 103.

[0029] The rack bar 103 is formed in a rod shape and transmits the force and amount of steering for steering the two wheels 112 respectively to the knuckle arm 111 by reciprocating displacement in the axial direction. It is composed of a metal material. In this case, a rack gear 103a is formed on a part of the rack bar 103, and the pinion gear 102a of the steering shaft 102 meshes with it. That is, the pinion gear 102a and the rack gear 103a constitute a rack & pinion mechanism (steering gear box) that converts the rotational motion of the steering shaft 102 into the reciprocating linear motion of the rack bar 103.

[0030] Both axial ends of this rack bar 103 are exposed from the rack housing 104 in a state where the rack & pinion mechanism is covered by the rack housing 104. And wheels 112 are connected to the respective exposed both ends of the rack bar 103 via an intermediate connector 105 and a knuckle arm 111 respectively.

[0031] The rack housing 104 is a component for covering and protecting the main parts such as the rack & pinion mechanism in the rack bar 103, and is formed by shaping a metal material into a cylindrical shape. This rack housing 104 is fixedly attached to the chassis (not shown) of the self-propelled vehicle.

[0032] The intermediate connecting body 105 is a component for transmitting the steering force and the 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 of the rack bar 103 and forms a linear damper 120, 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 forms a linear damper 120, and is formed by shaping 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 screwed into the tip of the rack bar 103 formed at the other end (the left side in the figure). The ball holding portion 107a is formed in a concave spherical shape so as to slidably fit and hold the ball portion 108a of the stud body 108. And a linear damper 120 is formed between the ball holding portion 107a and the male screw portion 107b in 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 formed by shaping a metal material into a round bar shape. This stud body 108 has a spherical ball portion 108a formed at one end (the left side in the figure), and a male screw portion (not shown) screwed into 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 such that a ball joint is movably attached to the tip of the rod-shaped tie rod body. Further, the knuckle arm 111 is a metal component for holding the wheel 112 with respect to the tie rod 110 and transmitting the steering force and steering amount transmitted from the tie rod 110 to the wheel 112, and is formed in a shape in which a plurality of rod-shaped bodies extend from around the cylindrical portion. Further, 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 such that rubber tires are attached to the outside of the metal wheels.

[0036] The direct-acting damper 120 is a device for absorbing the strong pressing force (impact) transmitted from the wheel 112, and is formed in each of the left and right intermediate connectors, more specifically, in each of the left and right socket bodies 107. This direct-acting damper 120 includes an inner chamber 121.

[0037] The inner chamber 121 is a portion that hermetically houses the fluid 124, and is formed in an annular cylindrical shape that extends in the axial direction while being notched in a concave shape along the circumferential direction on the outer peripheral portion of the socket body 107. That is, this socket body 107 constitutes the rack end 106 and is a component corresponding to the relative displacement body according to the present invention. In the present embodiment, the inner chamber 121 is formed by the socket body 107 itself at the bottom and one end (the right side in the drawing) in the axial direction of the socket body 107, and the other end (the left side in the drawing) in the axial direction is formed by the wall forming body 122. Further, the outside of the inner chamber 121 is covered by the inner chamber forming body 130.

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

[0039] The fluid 124 is a substance for applying a damping function to the direct-acting damper 120 by applying resistance to the flow control valve 140 that slides within the inner chamber 121, and fills the inner chamber 121. This fluid 124 is composed of a liquid, gel-like, or semi-solid substance having fluidity with viscosity according to the specifications of the direct-acting damper 120. In this case, the viscosity of the fluid 124 is appropriately selected according to the specifications of the direct-acting damper 120. In the present embodiment, the fluid 124 is composed of oil, for example, mineral oil or silicone oil. Note that the fluid 124 is shown by hatching within the dashed circle in FIGS. 3 and 5 (the same applies to FIGS. 9, 12 to 14, and 16 to 20).

[0040] Also, sliding bushes 125a and 125b are respectively fitted onto the outer peripheral surfaces of the socket body 107 and the wall forming member 122 on both sides in the axial direction of the socket body 107 with respect to the inner chamber 121. The sliding bushes 125a and 125b are components for smoothly reciprocating the inner chamber forming member 130 in the axial direction of the socket body 107, and are formed by shaping a metal material into an annular shape with an outer diameter slightly larger than the outer diameter of the socket body 107.

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

[0042] The inner chamber forming body 130 is a component that covers the radially outer side of the inner chamber 121 and in which the flow control valve 140 is formed, and is formed by shaping a metal material into a cylindrical shape. Specifically, the inner chamber forming body 130 is formed in a cylindrical shape that is slidably fitted to the outer peripheral surface of the socket body 107. In this case, the inner chamber forming body 130 is formed to have a length that protrudes from the end of the socket body 107 on the rack housing 104 side.

[0043] In the inner peripheral portion of this inner chamber forming body 130, the flow control valve 140 protrudes at the central portion in the axial direction, and an elastic body holding portion 131 is formed between the flow control valve 140 and the inner peripheral surface of the inner chamber forming body 130. Also, dust boots 133 and dust seals 134 are respectively provided at both axial ends of the inner peripheral portion of the inner chamber forming body 130.

[0044] The elastic body holding part 131 is a part that accommodates one end of both ends of the return elastic body 132, and is formed in an annular shape between the inner peripheral surface of the inner chamber forming body 130 and the flow control valve 140. The return elastic body 132 is a component for elastically pressing the flow control valve 140 to the left end (as shown in the figure) in the inner chamber 121, and is composed of a metal coil spring. One end (the left end as shown in the figure) of this return elastic body 132 is accommodated in the elastic body holding part 131 and elastically presses the inner chamber forming body 130, while the other end (the right end as shown in the figure) elastically presses the outer peripheral part of the socket body 107 via the sliding bush 125a. That is, the return elastic body 132 applies elastic forces to the inner chamber forming body 130 and the socket body 107 respectively so that the flow control valve 140 described later is positioned on the side where an external force acts on the direct-acting damper 120 (the rack housing 104 side).

[0045] The dust boot 133 is a component for preventing dust from entering the inside of the inner chamber forming body 130 from the side of the rack housing 104, which is one side (the left side as shown in the figure) of both ends of the inner chamber forming body 130, and is formed in a cylindrical shape from an elastomer material such as a rubber material. One end of this dust boot 133 is connected to the end of the inner chamber forming body 130, and the other end is connected to the wall forming body 122. In addition, in FIG. 2, the illustration of the dust boot 133 is omitted.

[0046] Similar to the dust boot 133, the dust seal 134 is a component for preventing dust from entering the inside of the inner chamber forming body 130 from the side of the stud body 108, which is the other side (the right side as shown in the figure) of both ends of the inner chamber forming body 130, and is formed in an annular shape from an elastomer material such as a rubber material. This dust seal 134 is fitted into a groove notched in an annular shape at the end of the inner chamber forming body 130.

[0047] An accumulator housing portion 135 is formed on the outer peripheral portion of the inner chamber forming body 130. The accumulator housing portion 135 is a cylindrical portion for liquid-tightly housing the accumulator 136, and is formed so as to project on the outer peripheral surface 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 housing portion 135 communicates with the first fluid flow body 153 side in the inner chamber 121, and the other end is sealed by a plug.

[0048] The accumulator 136 is a device for compensating for the volume change due to the expansion or contraction of the fluid 124 in the inner chamber 121 caused by the temperature change. This accumulator 136 is configured to house a piston that reciprocally slides within the accumulator housing portion 135 while being elastically pressed toward the inner chamber 121 side by a coil spring.

[0049] The flow control valve 140 is a device for generating the damping force of the direct-acting damper 120 by controlling the flow of the fluid 124 in the inner chamber 121 while restricting the flow. This flow control valve 140 mainly includes a valve support body 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 a portion where the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170 are respectively formed, and is formed in a flat plate annular shape that projects inward from the inner peripheral portion of the inner chamber forming body 130. The inner peripheral portion of this valve support body 141 is formed as a smooth cylindrical surface that slidably contacts the bottom of the inner chamber 121 in a liquid-tight manner, and a seal ring 142 made of an elastic body is fitted therein.

[0051] The first flow control valve 150 is a valve that functions as a trigger for generating the maximum damping force when a strong impact force acts on the direct-acting damper 120. It mainly includes a second flow body housing portion 151, a first flow body 153, a second flow body 156, and a separating elastic body 159 respectively. The second flow body housing portion 151 is a portion that houses the second flow body 156 to be described later in a slidable state, and is formed in a bottomed cylindrical shape that always opens at one end (the right side in the figure) of the valve support body 141.

[0052] In this case, the second flow body housing portion 151 is formed so as to always open on the front side surface when the inner chamber forming body 130 slides and displaces against the elastic force of the return elastic body 132 with respect to the socket body 107 among the two side surfaces of the valve support body 141. A retaining ring 152 is fitted into a ring-shaped groove formed on the inner peripheral surface near the opening of the second flow body housing portion 151. The retaining ring 152 is a component for preventing the second flow body 156 housed in the second flow body housing portion 151 from coming out, and is composed of a metal material in a C-shaped ring body.

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

[0054] The first aperture regulating portion 155 is a portion that blocks the flow of the fluid 124 in the second flow hole 157, and is formed in a wall shape around the first flow hole 154. And, the first aperture regulating portion 155 is formed at a position facing the second flow hole 157 so as to completely block the second flow hole 157 of the second fluid body 156 when the second fluid body 156 contacts the first fluid body 153. In the present embodiment, the first aperture regulating portion 155 is constituted by the bottom portion of the second fluid body accommodating portion 151.

[0055] The second fluid body 156 is a component for controlling the flow of the fluid 124 in cooperation with the first fluid body 153, and is formed by shaping a metal material into a cylindrical shape. In this case, the second fluid body 156 is composed of a large-diameter portion 156a that slides with respect to the inner peripheral surface of the second fluid body accommodating portion 151, and a small-diameter portion 156b that is smaller in diameter than the large-diameter portion 156a. And, a second flow hole 157 and a second aperture regulating portion 158 are respectively formed in the second fluid body 156.

[0056] The second flow hole 157 is a through hole for allowing the fluid 124 to flow through, and is composed of a large-diameter hole 157a and a small-diameter hole 157b that penetrate the second fluid body 156. The large-diameter hole 157a is formed to open on the front side surface when the inner chamber forming body 130 slides and displaces against the elastic force of the return elastic body 132 in the second fluid body 156. Also, the small-diameter hole 157b extends from the innermost part of the large-diameter hole 157a to the rear side surface and opens 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. Further, the small-diameter hole 157b is formed with a tapered portion 157d having a tapered shape in which the diameter continuously decreases toward the back side of the small-diameter hole 157b at the end on the large-diameter hole 157a side. Further, the small-diameter hole 157b is formed at a position and with a size that communicates with the large-diameter hole 157a and faces the first aperture regulating portion 155 without facing the first flow hole 154. That is, the small-diameter hole 157b is formed at a position and with a size that does not overlap the first flow hole 154 on the first aperture regulating portion 155. In the present 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 flow hole 154.

[0058] The second aperture regulating portion 158 is a portion that blocks the flow of the fluid 124 in the first flow hole 154, and is formed in a wall shape around the small-diameter hole 157b that constitutes the second flow hole 157. Specifically, the second aperture regulating portion 158 is formed at a position facing the first flow hole 154 so as to block a part of the first flow hole 154 of the first flow body 153 when the second flow body 156 contacts the first flow body 153. In the present embodiment, the second aperture regulating portion 158 is formed in a flat annular shape with a size that blocks about 1 / 3 of the first flow hole 154 of the first flow body 153 when the second flow body 156 contacts the first flow body 153.

[0059] The separating elastic body 159 is a component that exerts an elastic force for separating the second flow body 156 from the first flow body 153 in the second flow body accommodating portion 151, and is composed of a metal coil spring. One end (the left side in the drawing) of the separating elastic body 159 presses the first aperture regulating portion 155 (the bottom of the second flow body accommodating portion 151), and the other end (the right side in the drawing) fits on the outer peripheral portion of the small-diameter portion 156b. The elastic force of the separating elastic body 159 is set to a strength corresponding to the magnitude of the external force at which the linear damper 120 wants to generate the maximum damping force. One first flow control valve 150 is provided on the valve support body 141.

[0060] The second flow control valve 160 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 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 by the elastic force of the return elastic body 132. That is, the second flow control valve 160 is constituted by a one-way valve. Since the configuration of the one-way valve constituting the second flow control valve 160 is known, a detailed description thereof will be omitted. This second flow control valve 160 is provided at a position 180° in the circumferential direction with respect to the first flow control valve 150 in the valve support body 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 by the elastic force of the return elastic body 132, respectively. This third flow control valve 170 is constituted by a through-hole of a pore formed in the valve support body 141. In the present embodiment, the third flow control valves 170 are respectively 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. This steering device 100 is incorporated inside a self-propelled vehicle as a mechanism for steering a steering wheel (for example, two front wheels) of the four-wheel self-propelled vehicle (not shown) in the left-right direction. Then, this steering device 100 changes the orientation of each of the two wheels 112 according to the operation of the steering wheel 101 by the driver of the self-propelled vehicle to determine the traveling direction of the self-propelled vehicle.

[0063] During the operation of such a self-propelled vehicle, the linear damper 120 in the steering device 100 acts when the rack bar 103 is displaced close to the left and right displacement limits in relation to the pinion gear 102a. In this case, the displacement limit of the rack bar 103 is the left and right steering limits of the wheels 112. In addition to the case where the driver of the self-propelled vehicle rotates the steering wheel 101 close to the rotation limit clockwise or counterclockwise, there may be a case where the wheels 112 collide with an obstacle such as a curb and a large input acts on the rack bar 103 from the wheel 112 side.

[0064] First, the case where no external force acts on the linear damper 120 and the linear damper 120 does not operate will be described. As shown in FIG. 3, this linear damper 120 does not operate when the rack bar 103 does not reach near the displacement limit, such as when the wheels 112 of the self-propelled vehicle are not steered near 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, in the linear damper 120, the flow control valve 140 is pressed against the wall forming body 122 via the buffer material 123b by the elastic force of the return elastic body 132 in the inner chamber 121. That is, the inner chamber forming body 130 maintains a state of being elastically positioned at the position closest to the rack housing 104 on the socket body 107.

[0065] Also, the first flow control valve 150 maintains a state in which the second flow body 156 is positioned at the position most separated from the first flow body 153 by the elastic force of the separation elastic body 159. That is, the first flow control valve 150 is in a state where the flow of the fluid 124 is possible.

[0066] Next, the 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 near the displacement limit, such as when the wheel 112 of the self-propelled vehicle is steered to near the steering limit (see the dashed arrow), the end of the inner chamber forming body 130 contacts the rack housing 104 and starts to operate. In this case, the operation of the linear damper 120 may involve the end of the inner chamber forming body 130 contacting the rack housing 104 with a weak force or a strong force.

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

[0068] However, in this case, since the force with which the flow control valve 140 slowly displaces in the inner chamber 121 and presses the second flow body 156 is smaller than the elastic force of the separation elastic body 159, the second flow body 156 does not displace toward the first flow body 153 side and is not pressed against the first flow body 153. Therefore, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows toward the rear side in the displacement direction through the second flow hole 157 of the second flow body 156 and the first flow hole 154 of the first flow body 153 with a slight flow resistance (see the dashed arrow).

[0069] Also, since 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, there is no flow of the fluid 124. Further, since the third flow control valve 170 is a valve that allows the flow of the fluid 124 in both the front side and the rear side with respect to the displacement direction of the flow control valve 140, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 140 with a slight flow resistance.

[0070] Therefore, the flow control valve 140 displaces toward the buffer material 123a side while generating an extremely small damping force that can be ignored. As a result, the inner chamber forming body 130 slowly slides and displaces toward the stud body 108 side.

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

[0072] In this case, the second flow body 156 returns to its original position that is most separated from the first flow body 153 by the elastic force of the separation elastic body 159 and the pressing force of the fluid 124 flowing from the first flow body 153. For this reason, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows from the first flow hole 154 of the first flow body 153 and the second flow hole 157 of the second flow body 156 to the rear side in the displacement direction with a slight flow resistance.

[0073] In addition, 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 displaced by the elastic force of the return elastic body 132, the fluid 124 flows with a slight flow resistance. Also, since the third flow control valve 170 is a valve that allows the fluid 124 to flow in both the front side and the rear side with respect to the displacement direction of the flow control valve 140, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 140 with a slight flow resistance.

[0074] Therefore, the flow control valve 140 is displaced toward the buffer material 123b side while generating an extremely small damping force that can be ignored. As a result, the inner chamber forming body 130 slides and displaces toward the rack housing 104 more quickly than the previous displacement speed.

[0075] Next, when the end of the inner chamber forming body 130 contacts the rack housing 104 with a strong force (high speed) (for example, a sudden steering by the driver or a collision of the wheel 112 against a curbstone), the inner chamber forming body 130 slides and displaces rapidly toward the stud body 108 side with respect to the socket body 107. That is, the flow control valve 140 rapidly displaces toward the buffer material 123a side while resisting the elastic force of the return elastic body 132 inside the inner chamber 121.

[0076] In this case, as shown in FIG. 8, for the first flow control valve 150, since the force with which the fluid 124 presses the second flow body 156 is greater than the elastic force of the separation elastic body 159, it is displaced toward the first flow body 153 side and pressed against the first flow body 153. In this case, after the pressing force of the fluid 124 acts on the tapered portion 157d of the stepped portion 157c and the small-diameter hole 157b and the second flow body 156 starts to be displaced toward the first flow body 153 side, the pressing force of the fluid 124 also acts at the end of the large-diameter hole 157a and the second flow body 156 is displaced toward the first flow body 153 side.

[0077] Also, in this case, since the first aperture restricting portion 155 and the second aperture restricting portion 158 are formed at positions facing the second flow hole 157 and the first flow hole 154 respectively, they block all of the second flow hole 157 and a part of the first flow hole 154. Therefore, in the first flow control valve 150, there is no flow of the fluid 124 when the flow control valve 140 is displaced toward the stud body 108 side (see the dashed arrow). Also, in this case, in the second flow control valve 160, there is no flow of the fluid 124 as described above.

[0078] Further, in the third flow control valve 170, only the third flow control valve 170 in the flow control valve 140 allows the flow of the fluid 124, so a very large flow resistance is generated. Therefore, the flow control valve 140 is displaced toward the buffer material 123a side while resisting the very large flow resistance by the third flow control valve 170. As a result, the inner chamber forming body 130 slides and displaces toward the stud body 108 side while generating an extremely large damping force. That is, the linear damper 120 can attenuate the strong impact generated on the rack bar 103.

[0079] After that, when the rack bar 103 is displaced toward the knuckle arm 111 side 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 the original position by the elastic force of the return elastic body 132 in the same manner as described above (see FIG. 5). That is, the inner chamber forming body 130 quickly slides and displaces toward the rack housing 104 side by displacing toward the buffer material 123b side while generating an extremely small damping force that can be ignored by the flow control valve 140.

[0080] Further, the second flow body 156 returns to its original position separated from the first flow body 153 by the elastic force of the separation elastic body 159 and the pressing force of the fluid 124 flowing from the first flow body 153. In this case, since the second aperture restricting portion 158 is formed at a position facing a part of the first flow hole 154 in the second flow body 156, a part of the fluid 124 flowing into the second flow body accommodating portion 151 from the first flow hole 154 can be guided to the second flow hole 157 side. And, 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 flow hole 154 of the first flow body 153 and the second flow hole 157 of the second flow body 156, respectively, with a slight flow resistance to the rear side in the displacement direction.

[0081] As can be understood from the description of the above operation method, according to the above first embodiment, since the socket main body 107 as a relative displacement body is provided in a state of penetrating through the cylindrically formed inner chamber forming body 130 in the direct-acting damper 120, the direct-acting damper 120 can be provided on the outer side in the radial direction of the rack end 106 extending in the axial direction in the steering device 100 which is the object to be attached to the direct-acting damper 120, rather than in the axial direction of the rack end 106. It is possible to avoid an increase in the size (mainly, elongation) 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 the steering apparatus including the flow control valve and the direct-acting damper according to the present invention will be described with reference to FIGS. 9 to 13. The steering apparatus 200 in this second embodiment is different from the first embodiment in that a direct-acting damper 210 corresponding to the direct-acting damper 120 in the first embodiment is assembled to a rack housing 104 instead of a socket body 107. Therefore, in the steering apparatus 200 in this second embodiment, the description will focus on the parts different from the steering apparatus 200 in the first embodiment, and the description of the common parts or corresponding parts in both embodiments will be omitted as appropriate. Further, in the description of this second embodiment, the same reference numerals as those in the first embodiment are given to the components similar to those in the first embodiment.

[0083] (Configuration of Steering Apparatus 200) A cylindrical direct-acting damper 210 is attached to the tip of a cylindrical rack housing 104 forming the steering apparatus 200, and a dust boot 201 is attached so as to cover the direct-acting damper 210. The dust boot 201 is a component for preventing the direct-acting damper 210 from being soiled, and is formed by shaping an elastomer material such as a rubber material into a cylindrical shape.

[0084] Inside the cylindrical direct-acting damper 210 attached to the tip of the rack housing 104, a rack bar 103 penetrating the inside of the rack housing 104 penetrates. And a rack end 106 is attached to the tip of the rack bar 103. In this case, the socket body 107 attached to the rack bar 103 has an outer peripheral portion projecting in a flange shape from the outer peripheral portion 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 forms the inner chamber 217 and is a component for attaching 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. On one end (the left side in the figure) of the outer peripheral portion of this inner chamber forming body 211, a male screw portion 211a for screw-fitting to the rack housing 104 is formed, and on the other end side (the right side in the figure), an oil supply port 212 and an accumulator housing portion 213 are respectively formed.

[0086] The oil supply port 212 is a flow passage for injecting or discharging the fluid 124 into the inner chamber 217, and is closable by a plug in an openable and closable manner. The accumulator housing portion 213 and the accumulator 214 respectively correspond to the accumulator housing portion 135 and the accumulator 136 in the first embodiment. Further, wall forming bodies 215 and 216 are respectively screw-fitted to both ends inside the inner chamber forming body 211, and a cylindrical inner chamber 217 is formed between these two wall forming bodies 215 and 216.

[0087] The wall forming bodies 215 and 216 are components for forming the wall portions on both the left and right sides in the figure in the inner chamber 217, and are configured by forming a metal material into an annular shape. That is, the wall forming bodies 215 and 216 correspond to the wall forming bodies 122 in the first embodiment. Therefore, the inner chamber 217 is formed in an annular cylindrical shape extending in the axial direction between the inner side of the inner chamber forming body 211 and a relative displacement body 230 described later. A return elastic body 218 is fitted to the outer peripheral portion of the wall forming body 216 on the intermediate connecting body 105 side among these wall forming bodies 215 and 216.

[0088] The return elastic body 218 is a component for elastically pressing the flow control valve 240 against the right end portion in the inner chamber 217 as shown in the figure, and is constituted by a metal coil spring. That is, the return elastic body 218 corresponds to the return elastic body 132 in the above first embodiment. One end (left end in the figure) of this return elastic body 218 elastically presses the wall forming body 216, and the other end (right end in the figure) 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 130 and the socket body 107 so as to be located on the side (ball holding portion 107a side) where an external force acts on the direct-acting damper 210 respectively.

[0089] In addition, buffer materials 221a and 221b, sliding bushes 222a and 222b, seal rings 223a and 223b, and dust seals 224a and 224b corresponding to the buffer materials 123a and 123b, sliding bushes 125a and 125b, seal rings 126a and 126b, and dust seal 134 in the above first embodiment are respectively provided on the wall forming bodies 215 and 216.

[0090] The relative displacement body 230 is a component that covers the radially inner side of the inner chamber 217 and on which the flow control valve 240 is formed, and is formed by shaping a metal material into a cylindrical shape. That is, the relative displacement body 230 corresponds to the socket body 107 in the above first embodiment. This relative displacement body 230 is formed in a cylindrical shape that is slidably fitted to the inner peripheral surfaces of the wall forming bodies 215 and 216 via the sliding bushes 222a and 222b. In this case, the relative displacement body 230 is formed to have a length that protrudes from each end of the wall forming bodies 215 and 216. Also, the inner diameter of the relative displacement body 230 is formed to be of a size through which the rack bar 103 passes.

[0091] On the outer peripheral portion of the relative displacement body 230, the above-described receiving plate 218a is fixedly attached to one end (the right side in the drawing), and a fixing sleeve 231 and a flow control valve 240 are respectively attached from the other end (the left side in the drawing) to the axial center portion. The fixing sleeve 231 is a component for pressing and fixing the flow control valve 240 that fits into the small-diameter portion formed on the outer peripheral portion of the relative displacement body 230 against the large-diameter portion formed on the outer peripheral portion of the relative displacement body 230, and is formed of a metal material into a cylindrical shape. This fixing sleeve 231 is fitted to the outer peripheral portion of the relative displacement body 230 and assembled integrally, and slides with respect to the above-described wall forming body 215 via a sliding bush 222a.

[0092] The flow control valve 240 is a device for generating the damping force of the direct-acting damper 210 by controlling the flow of the fluid 124 while restricting the flow of the fluid 124 in the inner chamber 217, and corresponds to the flow control valve 140 in the first embodiment. This flow control valve 240 mainly includes a valve support body 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 in 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 formed of a metal material into a flat annular shape. That is, the valve support body 241 is configured separately from the relative displacement body 230 and is integrally attached 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 on the outer peripheral portion of this valve support body 241.

[0094] Since 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, the description thereof is omitted. And this flow control valve 240 is attached to the outer peripheral portion of the relative displacement body 230 in a direction in which the large-diameter portion 156a of the second flow body 156 of the first flow control valve 150 opens toward the buffer material 221a side (the left side in the drawing).

[0095] (Operation of the Steering Device 200) Next, the operation of the steering device 200 configured as described above will be described. Similar to the steering device 100 in the above embodiment, the linear damper 210 operates when the rack bar 103 is displaced near the left and right displacement limits in relation to the pinion gear 102a.

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

[0097] Also, the first flow control valve 150 maintains a state where the second flow body 156 is positioned at the position farthest from the first flow body 153 by the elastic force of the separation elastic body 159. That is, the first flow control valve 150 is in a state where the flow of the fluid 124 is possible.

[0098] Next, the linear damper 210 As shown in FIG. 11, when the rack bar 103 reaches near the displacement limit, such as when the wheels 112 of the self-propelled vehicle are steered near the steering limit, the socket body 107 contacts the end of the inner chamber forming body 130 and starts to operate.

[0099] First, when the socket body 107 contacts 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 side 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 drawing) in the inner chamber 217 against the elastic force of the return elastic body 218. In this case, in the first flow control valve 150, the fluid 124 flows from the large-diameter hole 157a side of the second flow hole 157 of the second flow body 156 toward the small-diameter hole 157b side.

[0100] However, in this case, since the force with which the flow control valve 240 slowly displaces in the inner chamber 217 and presses the second flow body 156 is smaller than the elastic force of the separation elastic body 159, the second flow body 156 does not displace toward the first flow body 153 side and is not pressed against the first flow body 153. Therefore, in the first flow control valve 150, the fluid 124 on the front side in the displacement direction flows toward the rear side in the displacement direction through the second flow hole 157 of the second flow body 156 and the first flow hole 154 of the first flow body 153 with a slight flow resistance.

[0101] Also, 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 240 when the relative displacement body 230 slides and displaces against the elastic force of the return elastic body 218. Therefore, there is no flow of the fluid 124. Further, since the third flow control valve 170 is a valve that allows the fluid 124 to flow in both the front side and the rear side with respect to the displacement direction of the flow control valve 240, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 240 with a slight flow resistance.

[0102] Therefore, the flow control valve 240 displaces toward the buffer material 123a side while generating an extremely small damping force that can be ignored. As a result, the relative displacement body 230 slowly slides and displaces toward the rack housing 104 side.

[0103] After that, when the rack bar 103 is displaced toward the knuckle arm 111 side and separated from the socket body 107 at the end of the relative displacement body 230, the relative displacement body 230 is displaced to its original position by the elastic force of the return elastic body 218 in the same manner as in the first embodiment (see FIG. 9). That is, the flow control valve 240 is displaced toward the buffer material 221b side 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 side more quickly than the previous displacement speed.

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

[0105] In this case, since the force with which the fluid 124 presses the second flow body 156 is greater than the elastic force of the separation elastic body 159, the first flow control valve 150 is displaced toward the first flow body 153 side and pressed against the first flow body 153. Also, in this case, since the first hole diameter regulating portion 155 and the second hole diameter regulating portion 158 are formed at positions facing the second flow hole 157 and the first flow hole 154, respectively, they block all of the second flow hole 157 and a part of the first flow hole 154, respectively. For this reason, in the first flow control valve 150, there is no flow of the fluid 124 when the flow control valve 240 is displaced toward the rack housing 104 side (see the dashed arrow). Also, in this case, in the second flow control valve 160, there is no flow of the fluid 124 as described above.

[0106] In addition, in the third flow control valve 170, since only the third flow control valve 170 can allow the fluid 124 to flow in the flow control valve 240, a very large flow resistance is generated. Therefore, the flow control valve 240 is displaced toward the buffer member 221a while resisting the very large flow resistance caused by the third flow control valve 170. As a result, the relative displacement body 230 slides and displaces toward the rack housing 104 side while generating an extremely large damping force. That is, the linear damper 210 can attenuate the strong impact generated on the rack bar 103.

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

[0108] Furthermore, in the implementation of the present invention, it is not limited to the above-described embodiments, and various modifications are possible without departing from the object of the present invention. In the description of each modification example, the same reference numerals are given to the same parts as those in the above-described embodiments, and the overlapping description is omitted.

[0109] For example, in each of the above-described embodiments, the linear dampers 120 and 210 are configured by providing the flow control valves 140 and 240 in the inner chambers 121 and 217. Thereby, the linear dampers 120 and 210 can reduce the size of the device configuration by providing the flow control valves 140 and 240 in the inner chambers 121 and 217. However, the linear dampers 120 and 210 can also be configured by providing part or all of the flow control valves 140 and 240 outside the inner chambers 121 and 217.

[0110] For example, FIGS. 14 and 15 show a linear damper 300 provided with a first flow control valve 150 in an inner chamber forming body 211 of the linear damper 210 according to the second embodiment. In this linear damper 300, a bypass flow path 301 is formed inside the inner chamber forming body 211, and the first flow control valve 150 which forms a part of the flow control valve 310 is provided on the outer peripheral portion of the inner chamber forming body 211 in a state of being connected to the bypass flow path 301. The bypass flow path 301 is a flow path of the fluid 124 that communicates the one end side and the other end side of the inner chamber 217 in the axial direction with each other 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 in which only the first flow control valve 150 is transferred to the inner chamber forming body 211 from the flow control valve 240 in the second embodiment. The first flow control valve 150 controls whether or not the fluid 124 flowing through the bypass flow path 301 can flow.

[0112] In this case, in the first flow control valve 150, a second fluid accommodation portion 151 is formed inside the inner chamber forming body 211 in a state of communicating with the inner chamber 217, and a second fluid 156 and a separating elastic body 159 are accommodated in the second fluid accommodation portion 151, respectively. On the side opposite to the inner chamber 217 side in the second fluid accommodation portion 151, an eccentric ring body (a component in which a through hole functioning as a first flow hole 154 is formed at a position eccentric from the center of a disk body functioning as a first hole diameter regulating portion) 155 constituting the first fluid 153 is fitted, and it communicates with the bypass flow path 301 through the first fluid 153. Further, in the inner chamber forming body 211, a bypass 301 extends so as to communicate with the outside of the inner chamber forming body 211 at a portion facing the second fluid accommodation portion 151 through the bypass flow path 301, and the extended flow path is blocked by a plug 302. bypass flow path 301 is blocked by a plug 302.

[0113] That is, the direct-acting damper 300 is configured by providing the second flow control valve 160 and the third flow control valve 170, which are part of the flow control valve 310, inside the inner chamber 217, and providing the first flow control valve 150, which is the other part, outside the inner chamber 217. The direct-acting damper 300 configured in this way operates in the same manner as the direct-acting damper 210 in the above-described second embodiment. In FIG. 14, the illustration of the rack bar 103 and the rack housing 104 is omitted respectively.

[0114] In this way, in the direct-acting damper 300, since at least part or all of the flow control valve 310 is provided outside the inner chamber 217, a large capacity of the inner chamber 217 can be ensured. Further, the direct-acting damper 300 can expose the first flow control valve 150 by removing the plug 302 in the inner chamber forming body 211, and the maintainability can be improved.

[0115] Also, 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 on one side (the side on which an external force acts on the direct-acting dampers 120, 210, 300) in the inner chambers 121, 217, the return elastic bodies 132, 218 can be omitted respectively.

[0116] Also, in the above-described first embodiment, the socket body 107 as the relative displacement body is formed in a shaft shape. However, the socket body 107 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 connect the rack bar 103 and the socket body 107 by screw fitting by forming a male screw at the tip of the rack bar 103 and forming a female screw in the through hole of the socket body 107.

[0117] Also, in each of the above embodiments, the first flow control valve 150 is configured such that the second aperture restricting portion 158 of the second flow body 156 closes a part of the first flow hole 154 of the first flow body 153, and the first aperture restricting portion 155 of the first flow body 153 closes all of the second flow hole 157 of the second flow body 156. However, the first flow control valve 150 only needs to be configured to close at least a part 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 close both the first flow hole 154 and the second flow hole 157, for example, as shown in FIG. 17. Also, the first flow control valve 150 can be configured to close a part of each of both the first flow hole 154 and the second flow hole 157. In this case, the first flow control valve 150 can be configured such that when the second flow body 156 is in close contact with the first flow body 153, a part of the first flow hole 154 and a part of the second flow hole 157 overlap each other to ensure the flow of the fluid 124, for example, as shown in FIG. 18. According to this, the flow control valves 140 and 240 can be configured by omitting the third flow control valve 170.

[0119] Also, the first flow control valve 150 can be configured to completely close one of the first flow hole 154 and the second flow hole 157 while not closing the other at all. For example, as shown in FIG. 19, the first flow control valve 150 can form a first aperture restricting portion 155 that protrudes columnarly 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 housing portion 151. In this case, the second aperture restricting portion 158 in the second flow body 156 is omitted. According to this, the first flow control valve 150 can close only the second flow hole 157 when the second flow body 156 abuts against the first aperture restricting portion 155.

[0120] Further, for example, as shown in FIGS. 20 and 21 respectively, the first flow control valve 150 can also be configured to provide a second hole diameter restricting portion 158 that protrudes columnarly toward the first flow hole 154 at a portion of the second flow body 156 facing the first flow hole 154, thereby closing only the first flow hole 154. In this case, the first hole diameter restricting portion 155 in the first flow body 153 is omitted. Also, in these cases, the columnar first hole diameter restricting portion 155 and / or the 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 close each hole.

[0121] Also, in each of the above embodiments, the second flow hole 157 is composed of two holes, namely a large diameter hole 157a and a small diameter hole 157b. However, the second flow hole 157 may be composed of only one hole, either the large diameter hole 157a or the small diameter hole 157b, or may be composed of three or more holes with different inner diameters. Further, a taper portion 157d is formed at the opening of the small diameter hole 157b on the side opposite to the first flow body 153. Thereby, the second flow body 156 can make it easier for the fluid 124 to flow into the second flow hole 157, and the operation of the first flow control valve 150 can be stabilized. Also, since the first flow control valve 150 can make it easier for the fluid 124 to flow into the second flow hole 157 and increase the flow rate, the second flow body 156 can be made more likely to be displaced toward the first flow body 153 due to the taper portion 157d receiving a strong pressing force from the fluid 124. However, it is natural that the second flow hole 157 may be formed in a straight shape by omitting the taper shape. Regarding the first flow hole 154, it may also be composed of a plurality of holes different from each other, or a taper shape may be formed at the opening of the hole.

[0122] 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 a first flow control valve 150, a second flow control valve 160, and a third flow control valve 170. Here, the second flow control valve 160 can improve the displacement speed during the return displacement of the flow control valves 140, 240. Also, the third flow control valve 170 can ensure the flow of the fluid 124 in a state where the second fluid body 156 is in close contact with the first fluid 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 according to the specifications of the direct-acting dampers 120, 210, 300. In these cases, the second flow control valve 160 may or may not be provided according to the specifications of the direct-acting dampers 120, 210, 300.

[0124] In each of the above embodiments, the direct-acting dampers 120, 210, 300 are applied to the steering devices 100, 200. However, the direct-acting dampers 120, 210, 300 can be attached to and used in devices or instruments other than the steering devices 100, 200, specifically, a suspension mechanism, a seat tilting mechanism, a door opening / closing mechanism, a mechanical device, an electrical device, an instrument, or furniture other than a self-propelled vehicle.

Description of Reference Numerals

[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 screw 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 part, 132... Return elastic body, 133... Dust boot, 134... Dust seal, 135... Accumulator accommodating part, 136... Accumulator, 140... Flow control valve, 141... Valve support body, 142... Seal ring, 150... First flow control valve, 151... Second fluid accommodating part, 152... Retaining ring, 153... First fluid, 154... First flow hole, 155... First hole diameter regulating part, 156... Second fluid, 156a... Large diameter part, 156b... Small diameter part, 157... Second flow hole, 157a... Large diameter hole, 157b... Small diameter hole, 157c... Step part, 157d... Taper part, 158... Second hole diameter regulating part, 159... Spacer 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 screw part, 212... Oil supply port, 213... Accumulator accommodating part, 214... Accumulator, 215, 216... Wall forming body, 217... Inner chamber, 218... Return elastic body, 218a... Receiving plate, 221a, 221b... Buffer 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 body, 242... Seal ring, 300... Linear damper, 301... Bypass flow path, 302... Plug, 310... Flow control valve.

Claims

1. A direct-acting damper comprising an inner chamber forming body having an inner chamber for liquid-tightly containing a fluid, and damping an external force received by the fluid by restricting the flow of the same fluid, wherein, a relative displacement body that relatively displaces with respect to the inner chamber forming body, and a flow control valve provided on at least one of the inner chamber forming body and the relative displacement body for allowing the fluid to flow while restricting the flow of the fluid are provided, the inner chamber forming body is formed in a cylindrical shape, and the inner chamber is formed inside the portion formed in the cylindrical shape, the relative displacement body is fitted slidably to the inner chamber forming body in a state where both ends penetrate through the inside of the inner chamber forming body and are exposed to the outside of the inner chamber forming body. The direct-acting damper is characterized by this.

2. The direct-acting damper according to claim 1, further comprising a return elastic body that applies an elastic force to at least one of the inner chamber forming body and the relative displacement body so that the flow control valve is located on the side where the external force acts with respect to the direct-acting damper. The direct-acting damper is characterized by this.

3. The direct-acting damper according to claim 1 or claim 2, wherein the relative displacement body is formed in a cylindrical shape. The direct-acting damper is characterized by this.

4. The direct-acting damper according to any one of claims 1 to 3, wherein the flow control valve is provided at least on the inner chamber forming body. The direct-acting damper is characterized by this.

5. The direct-acting damper according to any one of claims 1 to 4, wherein the flow control valve is provided at least on the relative displacement body. The direct-acting damper is characterized by this.

6. The direct-acting damper according to any one of claims 1 to 5, wherein the flow control valve is provided at least outside the inner chamber. The direct-acting damper is characterized by this.

7. A steering shaft that extends in a rod shape and rotates by operating a steering wheel, a rack bar that extends in a rod shape and converts the rotational movement of the steering shaft into a reciprocating movement in the axial direction and transmits it, an intermediate connecting body that is connected to both ends of the rack bar and directly or indirectly connects wheels to be steered to both ends thereof, and a rack housing that covers the rack bar. In a steering apparatus comprising these, a direct-acting damper according to any one of claims 1 to 6 is provided, and the direct-acting damper is ​ A steering device provided between the rack housing and the rack bar or the intermediate connecting body, and characterized by damping the impact from the wheel. **Claim 8** In the steering device according to Claim 7, the relative displacement body is formed on the intermediate connecting body, the inner chamber forming body, is formed at a position where it contacts or separates from the rack housing due to the reciprocating motion of the rack bar, and is a steering device characterized by this. **Claim 9** In the steering device according to Claim 7, the inner chamber forming body is formed at the end of the rack housing, the relative displacement body, has the rack bar or the intermediate connecting body penetrating therethrough, and is formed at a position where the rack bar or the intermediate connecting body contacts or separates due to the reciprocating motion of the rack bar, and is a steering device characterized by this.

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