Direct-acting dampers and steering devices

Abstract

Provided are a direct-acting damper and a steering device having the direct-acting damper, which can avoid the enlargement of the device structure of the installation object and can expand the types of installation objects that can be installed. The steering device (100) includes a direct-acting damper (120) between a rack rod (103) and a rack ball joint mechanism (106). The direct-acting damper (120) forms an inner cavity (121) between the inner side of an inner cavity forming body (130) and a socket body (107). The socket body (107) is an axial component that constitutes the rack ball joint mechanism (106) in the steering device (100) and is slidably engaged with the inner cavity forming body (130). The inner cavity forming body (130) is formed in a cylindrical shape and a flow control valve (140) is formed in an annular shape on the inner circumference. The flow control valve (140) is composed of a first flow control valve (150), a second flow control valve (160), and a third flow control valve (170).

Description

Technical Field

[0001] The present invention relates to a linear motion damper for damping kinetic energy in linear motion and a steering device including the linear motion damper. Background Art

[0002] Conventionally, there are linear dampers that damp kinetic energy in linear motion. For example, Patent Document 1 below discloses a linear damper in which a piston rod reciprocates linearly within a cylindrical cylinder filled with fluid oil.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 7-238970

[0004] However, the linear damper disclosed in Patent Document 1 is mounted on the front end of a component that reciprocates in a linear direction in an object. This causes a problem in that the device structure of the object becomes larger (mainly longer) and the objects that can be mounted are limited. Summary of the Invention

[0005] The present invention has been made to address the above-mentioned problems, and its object is to provide a linear damper and a steering device equipped with the same, which can avoid the enlargement (mainly elongation) of the device structure of the mounting object and can expand the types of mounting objects.

[0006] In order to achieve the above-mentioned purpose, the present invention is a direct-acting damper, which has an inner cavity forming body having an inner cavity for liquid-tightly accommodating a fluid, so that the external force exerted on the fluid is attenuated by restricting the flow of the fluid. It is characterized in that it has: a relative displacement body, which is relatively displaced relative to the inner cavity forming body; and a flow control valve, which is arranged on at least one of the inner cavity forming body and the relative displacement body, and restricts the flow of the fluid. The inner cavity forming body is formed into a cylindrical shape and an inner cavity is formed on the inner side of the part formed into the cylindrical shape. The relative displacement body passes through the inner cavity forming body and is slidably embedded in the inner cavity forming body.

[0007] According to the characteristics of the present invention constructed in this manner, since the direct-acting damper is provided with a relative displacement body in a state of penetrating the inner cavity forming body formed into a cylindrical shape, the direct-acting damper can be provided on the outside of the portion extending in an axial direction of the portion in the object to be installed of the direct-acting damper, rather than in the axial direction of the portion, thereby avoiding the enlargement (mainly elongation) of the device structure of the object to be installed and expanding the types of objects that can be installed.

[0008] In addition, based on the above-mentioned direct-acting damper, another feature of the present invention is that it also has a reset elastic body, which imparts elastic force to at least one of the inner cavity forming body and the relative displacement body so that the flow control valve is located on the side where the external force acts on the direct-acting damper.

[0009] According to another feature of the present invention thus constructed, the return elastic body of the direct-acting damper applies a spring force to one of the inner cavity-forming body and the relative displacement body, elastically displacing the flow control valve toward one end within the relative displacement range. Thus, in the absence of an external force causing relative displacement between the inner cavity-forming body and the relative displacement body, the direct-acting damper of the present invention can maintain the relative displacement body at one end within the relative displacement range, i.e., at the operational starting position for the flow control valve's damping function, thereby maximizing the relative displacement body's stroke.

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

[0011] According to other features of the present invention constructed in this manner, since the relative displacement body of the direct-acting damper is formed in a cylindrical shape, the direct-acting damper can be installed in a state where the axially extended portion of the installation object of the direct-acting damper passes through the relative displacement body, thereby avoiding the enlargement (mainly elongation) of the device structure of the installation object and expanding the types of installation objects that can be installed.

[0012] Furthermore, in addition to the above-mentioned direct-acting damper, another feature of the present invention is that the flow control valve is provided at least in the inner cavity forming body.

[0013] According to another feature of the present invention thus constituted, in the direct-acting damper, since the flow control valve is provided at least in the inner cavity forming body, the structure of the relative displacement body can be simplified.

[0014] Furthermore, in addition to the above-mentioned direct-acting damper, another feature of the present invention is that the flow control valve is provided at least on the relative displacement body.

[0015] According to other features of the present invention constructed in this way, since the flow control valve of the direct-acting damper is at least arranged on the relative displacement body, the structure of the inner cavity forming body can be simplified, and the flow control valve is provided on the outer periphery of the relative displacement body, so that maintenance can be easily performed by removing the relative displacement body from the inner cavity forming body.

[0016] Furthermore, in addition to the above-mentioned direct-acting damper, another feature of the present invention is that the flow control valve is provided at least outside the inner cavity.

[0017] According to another feature of the present invention thus constituted, since the flow control valve of the direct-acting damper is provided at least outside the inner cavity, a large capacity of the inner cavity can be ensured, and maintainability of the flow control valve can be improved.

[0018] Furthermore, the present invention can be implemented not only as an invention of a linear motion damper but also as an invention of a steering device including the linear motion damper.

[0019] Specifically, the steering device includes: a steering shaft extending into a rod-like shape and rotating in response to steering wheel operation; a rack bar extending into a rod-like shape and transmitting the steering shaft's rotational motion into axially reciprocating motion; an intermediate connecting body connected to each end of the rack bar, directly or indirectly connected to wheels to be steered; and a rack housing covering the rack bar. The steering device includes the direct-acting damper according to any one of claims 1 to 6, the direct-acting damper being disposed between the rack housing and the rack bar or the intermediate connecting body to attenuate impact from the wheels. Thus, the steering device of the present invention can achieve the same effects as the direct-acting damper described above.

[0020] In this case, in the above-described steering device, the relative displacement body is formed in the intermediate connecting body, and the inner cavity forming body is formed at a position where it contacts or separates from the rack housing by the reciprocating motion of the rack bar.

[0021] Therefore, the relative displacement body of the steering device of the present invention is formed in the rack ball joint mechanism that connects the transverse rod relative to the rack rod to be movable, and the inner cavity forming body is formed at a position that contacts or separates from the rack housing through the reciprocating motion of the rack rod, and the direct-acting damper is arranged in an intermediate connecting body such as the transverse rod or the rack ball joint mechanism, so that the direct-acting damper can be easily maintained or replaced.

[0022] In addition, in this case, based on the above-mentioned steering device, an inner cavity forming body is formed at the end of the rack housing, and the relative displacement body is penetrated by a rack rod or an intermediate connecting body inside, and is formed at a position where it contacts or separates from the rack rod or the intermediate connecting body through the reciprocating motion of the rack rod.

[0023] Thus, the steering system of the present invention includes a relative displacement body, wherein an inner cavity-forming body is disposed at the end of the rack housing, and an intermediate connecting body (such as a tie rod or rack ball joint mechanism) extends through the interior of the relative displacement body and contacts or separates from the rack rod or tie rod through the reciprocating motion of the rack rod. Thus, since the linear damper of the steering system of the present invention is disposed in the rack housing, the tie rod and intermediate connecting body (such as a tie rod or rack ball joint mechanism) can be lightweight. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an explanatory diagram schematically showing the outline of the overall structure of the steering device according to the first embodiment of the present invention.

[0025] Figure 2 It means composition Figure 1The illustrated schematic perspective view shows the external structure of a linear motion damper according to the first embodiment of the steering device of the present invention.

[0026] Figure 3 Yes Figure 2 A cross-sectional view schematically showing the internal structure of the linear damper shown.

[0027] Figure 4 It means from Figure 3 The cross-sectional view of the relative displacement body and the socket body observed along line 4-4 is shown.

[0028] Figure 5 It is expressed in detail in Figure 3 A partially enlarged view of the structure within the dotted circle 5 in the linear damper is shown.

[0029] Figure 6 It means in Figure 3 The cross-sectional view shows the state of the linear damper at the moment when the relative displacement body contacts the rack housing.

[0030] Figure 7 It shows that Figure 5 A partially enlarged view of a state in which the first flow control valve in the direct-acting damper causes fluid to flow is shown.

[0031] Figure 8 It shows that Figure 5 A partially enlarged view of a direct-acting damper showing a state in which the first flow control valve does not allow fluid to flow.

[0032] Figure 9 It is a cross-sectional view schematically showing the internal structure of a linear motion damper according to a second embodiment of the present invention.

[0033] Figure 10 It only means from Figure 9 The front view of the flow control valve as viewed from line 10-10 is shown.

[0034] Figure 11 It means in Figure 9 The cross-sectional view of the linear damper shows the state at the moment when the socket body and the relative displacement body come into contact.

[0035] Figure 12 It is aimed at Figure 9 The portion indicated by the dotted circle 12 in the illustrated direct-acting damper is a partially enlarged view showing a state in which the first flow control valve causes the fluid to flow.

[0036] Figure 13 It shows that Figure 9 A partially enlarged view of a direct-acting damper showing a state in which the first flow control valve does not allow fluid to flow.

[0037] Figure 14 It is a cross-sectional view schematically showing the internal structure of a linear motion damper according to a modified example of the present invention.

[0038] Figure 15 It only means from Figure 14 The main view of the flow control valve as viewed along line 15-15 is shown.

[0039] Figure 16 It is a cross-sectional view schematically showing the internal structure of a linear motion damper according to another modified example of the present invention.

[0040] Figure 17 This is a partially enlarged view showing a state in which both the first flow hole and the second flow hole are completely blocked and the first flow control valve does not allow the fluid to flow in the linear damper according to a modified example of the present invention.

[0041] Figure 18 This is a partially enlarged view showing a state in which a portion of the first flow hole and a portion of the second flow hole overlap with each other to ensure the flow of the fluid in a linear motion damper according to another modified example of the present invention.

[0042] Figure 19 This 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 linear damper according to another modified example of the present invention.

[0043] Figure 20 This 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 the linear damper according to a modified example of the present invention.

[0044] Figure 21 Yes Figure 20 A partially enlarged perspective view of the appearance structure of the front end portion of the second flow body is shown. DETAILED DESCRIPTION

[0045] <First embodiment>

[0046] Hereinafter, a first embodiment of a linear motion damper and a steering system including the same according to the present invention will be described with reference to the drawings. Figure 1 : is an explanatory diagram schematically showing the outline of the overall structure of the steering device 100 according to the first embodiment of the present invention. Figure 2 It means composition Figure 1 The steering device 100 shown in FIG. 1 is a perspective view schematically showing the appearance structure of the linear damper 120 according to the first embodiment of the present invention. Figure 3 Yes Figure 2 The schematic cross-sectional view of the internal structure of the linear damper 120 is shown. Figure 4 It means from Figure 3 The cross-sectional view of the inner cavity forming body 130 and the socket body 107 as viewed along line 4-4 is shown. Figure 5 It is expressed in detail in Figure 3 The diagram is a partially enlarged view of the structure within the dotted circle 5 of the linear damper 120.

[0047] 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 left and right directions.

[0048] (Structure of Steering Device 100)

[0049] The steering device 100 includes a steering wheel 101. The steering wheel 101 is an operating member (i.e., a handle) for the driver of the self-propelled vehicle to manually control the direction of travel, and is formed by forming a resin material or a metal material into an annular shape. A steering shaft 102 is connected to the steering wheel 101.

[0050] The steering shaft 102 is a rod-shaped component that rotates about its axis in response to clockwise or counterclockwise rotation of the steering wheel 101. It is composed of one or more metal rods connected via a universal joint, etc. The steering shaft 102 is connected to the steering wheel 101 at one end, and has a pinion 102a formed at the other end, which is connected to the rack bar 103.

[0051] The rack bar 103 is a rod-shaped component that moves back and forth along its axis, transmitting the steering force and steering amount applied to each of the two wheels 112 to the knuckle arm 111. It is made of metal. In this case, a rack gear 103a is formed in a portion of the rack bar 103, which engages with the pinion 102a of the steering shaft 102. In other words, the pinion 102a and 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.

[0052] The two axial ends of the rack bar 103 are exposed from the rack housing 104 when the rack and pinion mechanism is covered by the rack housing 104. The two ends of the rack bar 103 exposed from the rack housing 104 are connected to wheels 112 via an intermediate connector 105 and a knuckle arm 111.

[0053] The rack housing 104 is a member for covering and protecting the main parts such as the rack and pinion mechanism in the rack bar 103 and is formed of a metal material in a cylindrical shape. The rack housing 104 is fixedly mounted on a chassis (not shown) of the self-propelled vehicle.

[0054] 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. It is mainly composed of a rack ball joint mechanism 106 and a tie rod 110. The rack ball joint mechanism 106 movably connects the front end of the tie rod 110 to the rack bar 103 and forms the linear damper 120. It is mainly composed of a socket body 107 and a stud body 108.

[0055] The socket body 107 is a component that connects the stud body 108 to the front end of the rack rod 103 so that it can move and forms the direct-acting damper 120. It is made of a metal material formed into a round rod shape. The socket body 107 has a ball retaining portion 107a formed at one end (the right side in the figure) and an externally threaded portion 107b formed on the other end (the left side in the figure) that screws into the front end of the rack rod 103. The ball retaining portion 107a is formed into a concave spherical shape so that it can slidably fit and retain the ball portion 108a of the stud body 108. Furthermore, the direct-acting damper 120 is formed between the ball retaining portion 107a and the externally threaded portion 107b in the socket body 107.

[0056] The stud body 108 is a component used to movably connect the tie rod 110 to the socket body 107. It is formed of a metal material formed into a round rod shape. The stud body 108 has a spherical ball portion 108a formed at one end (the left side in the figure) and an external thread portion (not shown) formed on the other end (the right side in the figure) to be screwed into the end of the tie rod 110.

[0057] Tie rod 110 is a component that movably connects knuckle arm 111 to the front end of rack ball joint mechanism 106. A ball joint is movably mounted on the front end of a rod-shaped tie rod body. Knuckle arm 111 is a metal component that holds wheel 112 relative to tie rod 110 and transmits the steering force and steering amount transmitted from tie rod 110 to wheel 112. It is formed in the shape of multiple rod-shaped members extending from the periphery of a cylindrical portion. Wheels 112 are a pair of left and right components that rotate on the road surface to move the self-propelled vehicle forward or backward. Rubber tires are mounted on the outer sides of the metal wheels.

[0058] The linear damper 120 is a device for absorbing a strong pressing force (impact) transmitted from the wheel 112 and is formed in each of the left and right intermediate connecting bodies, more specifically, in each of the left and right socket bodies 107. The linear damper 120 includes an inner cavity 121.

[0059] The inner cavity 121 is a portion that liquid-tightly accommodates the fluid 124, and is formed into a circular cylindrical shape that is cut into a concave shape along the circumferential direction on the outer periphery of the socket body 107 and extends along the axial direction. That is, the socket body 107 is a component that constitutes the rack ball joint mechanism 106 and is equivalent to the relative displacement body of the present invention. In this embodiment, the bottom of the inner cavity 121 and the end on one side of the axial direction of the socket body 107 (the right side in the figure) are respectively formed by the socket body 107 itself, and the end on the other side of the axial direction (the left side in the figure) is formed by the wall forming body 122. In addition, the outside of the inner cavity 121 is covered by the inner cavity forming body 130.

[0060] The wall-forming member 122 is a component that forms the wall portion (left side in the figure) of the inner cavity 121. It is formed by forming a metal material into a circular ring shape. This wall-forming member 122 is screwed onto the outer peripheral surface of the socket body 107 on the other axial side (left side in the figure), becoming integral with the socket body 107. Furthermore, cushioning materials 123a and 123b, each made of an elastic material such as polyurethane resin, are provided at both axial ends of the socket body 107 in the inner cavity 121. In this case, cushioning material 123a is formed to be thicker than cushioning material 123b.

[0061] The fluid 124 is a substance that allows the direct-acting damper 120 to function as a damper by imparting resistance to the flow control valve 140 sliding in the inner cavity 121, and is filled in the inner cavity 121. The fluid 124 is composed of a liquid, gel, or semi-solid substance with a viscosity and fluidity corresponding 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 this embodiment, the fluid 124 is composed of oil, such as mineral oil or silicone oil. In addition, the fluid 124 is Figure 3 and Figure 5 Indicated by the hatched line in the dotted circle ( Figure 9 、 Figures 12 to 14 as well as Figures 16 to 20 Same).

[0062] Furthermore, sliding bushings 125a and 125b are respectively embedded in the outer peripheral surfaces of the socket body 107 and the wall forming body 122 on both sides of the inner cavity 121 in the axial direction of the socket body 107. The sliding bushings 125a and 125b are components for allowing the inner cavity forming body 130 to slide back and forth smoothly along the axial direction of the socket body 107. They are formed of a metal material into an annular shape with an outer diameter slightly larger than that of the socket body 107.

[0063] Seal rings 126a and 126b, each made of an elastomeric material such as rubber, are embedded in the outer peripheral surfaces of the socket body 107 and the wall forming body 122 on the side opposite to the inner cavity 121 relative to the sliding bushings 125a and 125b. These seal rings 126a and 126b prevent the fluid 124 in the inner cavity 121 from leaking out when the inner cavity forming body 130 slides relative to the socket body 107.

[0064] The inner cavity forming body 130 is a component that covers the radially outer side of the inner cavity 121 and forms the flow control valve 140. It is formed by forming a metal material into a cylindrical shape. Specifically, the inner cavity 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 cavity forming body 130 is formed to a length that protrudes from the end of the socket body 107 on the rack housing 104 side.

[0065] A flow control valve 140 is formed in a protruding shape at the axial center of the inner periphery of the inner cavity forming body 130, and an elastic retaining portion 131 is formed between the flow control valve 140 and the inner periphery of the inner cavity forming body 130. Furthermore, a dust cover 133 and a dust seal 134 are provided at both axial ends of the inner periphery of the inner cavity forming body 130, respectively.

[0066] The elastic body retaining portion 131 houses one of the two ends of the reset elastic body 132 and is formed into a circular ring between the inner circumferential surface of the inner cavity forming body 130 and the flow control valve 140. The reset elastic body 132 is a component used to elastically press the flow control valve 140 toward the left end in the figure within the inner cavity 121 and is composed of a metal coil spring. One end (the left end in the figure) of the reset elastic body 132 is housed in the elastic body retaining portion 131 to elastically press the inner cavity forming body 130, while the other end (the right end in the figure) elastically presses the outer circumference of the socket body 107 via the sliding bushing 125a. In other words, the reset elastic body 132 imparts elastic force to the inner cavity forming body 130 and the socket body 107, respectively, so that the flow control valve 140, described later, is positioned on the side (the rack housing 104 side) where the external force acts on the direct-acting damper 120.

[0067] The dust cover 133 is a component for preventing dust from entering the interior of the inner cavity forming body 130 from one of the two ends of the inner cavity forming body 130 (the left side in the figure), that is, the rack housing 104 side. It is formed of an elastic material such as rubber material into a cylindrical shape. One end of the dust cover 133 is connected to the end of the inner cavity forming body 130, and the other end is connected to the wall forming body 122. In addition, Figure 2 In the figure, the dust cover 133 is omitted.

[0068] The dust seal 134, like the dust cover 133, is a member for preventing dust from entering the interior of the inner cavity forming body 130 from the other (right side in the figure) of the two ends of the inner cavity forming body 130, i.e., the stud body 108 side. It is formed of an elastic material such as rubber formed into an annular shape. The dust seal 134 is embedded in an annular groove cut into the end of the inner cavity forming body 130.

[0069] An accumulator housing portion 135 is formed on the outer periphery of the inner cavity forming body 130. Accumulator housing portion 135 is a cylindrical portion for fluid-tightly housing accumulator 136. It is formed so as to protrude from the outer periphery of the inner cavity forming body 130 and extend along the longitudinal direction of the inner cavity forming body 130. One end of accumulator housing portion 135 communicates with the first flow body 153 side in the inner cavity 121, and the other end is sealed by a plug.

[0070] The accumulator 136 compensates for volume changes caused by expansion or contraction of the fluid 124 in the inner cavity 121 due to temperature changes. The accumulator 136 houses a piston that reciprocates in the accumulator housing 135 and is elastically pressed toward the inner cavity 121 by a coil spring.

[0071] The flow control valve 140 is a device for controlling the flow of the fluid 124 within the inner chamber 121 by restricting the flow of the fluid 124 and thereby generating a damping force in the linear damper 120. The flow control valve 140 primarily includes a valve support 141, a first flow control valve 150, a second flow control valve 160, and a third flow control valve 170.

[0072] The valve support body 141 forms the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170, respectively. It is formed into a flat, annular shape that protrudes inward from the inner periphery of the cavity-forming body 130. The inner periphery of the valve support body 141 is formed into a smooth cylindrical surface to slide fluid-tightly against the bottom of the cavity 121, and a sealing ring 142 made of an elastomer is embedded in it.

[0073] The first flow control valve 150 functions as a trigger for generating the maximum damping force when a strong impact force acts on the direct-acting damper 120. It primarily comprises a second flow body housing 151, a first flow body 153, a second flow body 156, and a separating elastic body 159. The second flow body housing 151 slidably houses the second flow body 156, described later, and is formed in the shape of a bottomed cylinder with an open end at one end (the right side in the figure) of the valve support body 141.

[0074] In this case, the second flow body housing portion 151 is formed so that the side surface on the front side of the valve support body 141 remains open when the inner cavity 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 embedded in an annular groove formed on the inner circumference of the second flow body housing portion 151 near the opening. The retaining ring 152 is a component used to prevent the second flow body 156 housed in the second flow body housing portion 151 from falling out. It is formed of a metal material in the form of a C-shaped ring.

[0075] 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 primarily comprises a first flow hole 154 and a first aperture limiting portion 155. The first flow hole 154 is a through-hole for allowing the fluid 124 to flow, and is formed at the bottom of the second flow body housing 151. In this case, the first flow hole 154 is formed at the edge of the bottom, which is eccentric with respect to the centerline of the second flow body housing 151. That is, one side of the inner cavity 121 of the second flow body housing 151 (the side with the buffer material 123a) has a larger opening, while the other side (the side with the buffer material 123b) has a smaller opening due to the first flow hole 154.

[0076] The first aperture restrictor 155 blocks the flow of the fluid 124 in the second flow hole 157 and is formed in a wall-like shape around the first flow hole 154. Furthermore, the first aperture restrictor 155 is formed at a position opposite the second flow hole 157 so as to completely block the second flow hole 157 of the second flow body 156 when the second flow body 156 is in contact with the first flow body 153. In this embodiment, the first aperture restrictor 155 is formed by the bottom of the second flow body housing 151.

[0077] The second flow body 156 is a component used to control the flow of the fluid 124 in conjunction with the first flow body 153. It is formed by forming a metal material into a cylindrical shape. In this case, the second flow body 156 consists of a large-diameter portion 156a that slides relative to the inner circumference of the second flow body housing 151, and a small-diameter portion 156b with a smaller diameter than the large-diameter portion 156a. Furthermore, the second flow body 156 is formed with a second flow hole 157 and a second aperture restriction 158.

[0078] The second flow 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 flow body 156. The large-diameter hole 157a is formed in the second flow body 156 so as to open on the side surface on the front side when the inner cavity forming body 130 slides against the elastic force of the return elastic body 132. Furthermore, the small-diameter hole 157b extends from the innermost portion of the large-diameter hole 157a to the side surface on the rear side when the inner cavity forming body 130 slides against the elastic force of the return elastic body 132, and opens.

[0079] In this case, a flat, annular step 157c is formed between the large-diameter hole 157a and the small-diameter hole 157b. Furthermore, the end of the small-diameter hole 157b on the large-diameter hole 157a side is formed with a tapered portion 157d, whose diameter tapers continuously toward the inside of the small-diameter hole 157b. Furthermore, the small-diameter hole 157b is positioned and sized to communicate with the large-diameter hole 157a and to face the first aperture restrictor 155, rather than the first flow hole 154. In other words, the small-diameter hole 157b is positioned and sized on the first aperture restrictor 155 so as not to overlap with the first flow hole 154. In this embodiment, the small-diameter hole 157b is concentric with the second flow body 156 and the large-diameter hole 157a and has a smaller diameter than the first flow hole 154.

[0080] The second aperture restrictor 158 blocks the flow of the fluid 124 in the first flow hole 154 and is formed as a wall around the small-diameter hole 157b that constitutes the second flow hole 157. Specifically, the second aperture restrictor 158 is formed opposite the first flow hole 154 so that it blocks a portion 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 this embodiment, the second aperture restrictor 158 is formed as a flat ring having a size of approximately one-third of the first flow hole 154 of the first flow body 153 when the second flow body 156 contacts the first flow body 153.

[0081] 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 housing 151. It is composed of a metal coil spring. One end of the separating elastic body 159 (left side in the figure) presses against the first aperture limiting portion 155 (the bottom of the second circulating body housing 151), while the other end (right side in the figure) engages with the outer periphery 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 that is intended to generate the maximum damping force of the direct-acting damper 120. The first flow control valve 150 is provided in one valve support body 141.

[0082] The second flow control valve 160 is a valve that prevents the fluid 124 from flowing from the front side to the rear side of the sliding displacement when the inner cavity forming body 130 slides relative to the socket body 107, overcoming the elastic force of the reset elastic body 132. Furthermore, when the inner cavity forming body 130 slides due to the elastic force of the reset elastic body 132, it allows the fluid 124 to flow easily from the front side to the rear side of the sliding displacement. In other words, the second flow control valve 160 is composed of a one-way valve. The structure of the one-way valve constituting the second flow control valve 160 is well known, so a detailed description is omitted. The second flow control valve 160 is provided in the valve support body 141 at a position 180° circumferentially relative to the first flow control valve 150.

[0083] The third flow control valve 170 is a valve that restricts the flow of the fluid 124, allowing it to circulate, when the inner cavity forming body 130 slides relative to the socket body 107 against the elastic force of the return elastic body 132, and when the inner cavity forming body 130 slides relative to the socket body 107 due to the elastic force of the return elastic body 132. The third flow control valve 170 is formed by a through-hole, which is a fine hole formed in the valve support body 141. In this embodiment, the third flow control valve 170 is 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.

[0084] (Operation of Steering Device 100)

[0085] Next, the operation of the steering system 100 configured as described above will be described. The steering system 100 is incorporated into a four-wheeled self-propelled vehicle (not shown) as a mechanism for steering the steering wheels (e.g., the two front wheels) in the left and right directions. Furthermore, the steering system 100 changes the directions of the two wheels 112 in response to the driver's operation of the steering wheel 101, thereby determining the vehicle's travel direction.

[0086] During operation of this self-propelled vehicle, when the rack bar 103 is displaced to near its left or right displacement limit relative to the pinion 102a, the direct-acting damper 120 in the steering system 100 comes into play. In this case, the rack bar 103's displacement limit refers to the left or right steering control limit of the wheels 112. In addition to situations where the driver of the self-propelled vehicle turns the steering wheel 101 clockwise or counterclockwise to near its rotation limit, there are also situations where a wheel 112 collides with an obstacle such as a curb, causing a large input to act on the rack bar 103 from the wheel 112 side.

[0087] First, the case where the direct-acting damper 120 does not work due to the absence of external force will be described. Figure 3As shown, when the rack bar 103 is within a range close to its displacement limit, such as when the wheels 112 of the self-propelled vehicle are not steered to near the steering limit, the inner cavity forming body 130 does not collide with the rack housing 104, and thus the linear damper 120 does not operate. Figure 5 As shown, 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 cavity 121 by the elastic force of the return elastic body 132. In other words, the inner cavity-forming body 130 is maintained in a state where it is elastically positioned on the socket body 107 at the position closest to the rack housing 104.

[0088] Furthermore, the first flow control valve 150 maintains the second flow body 156 positioned 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.

[0089] Next, the operation of the direct-acting damper 120 caused by the external force acting on the direct-acting damper 120 will be described. Figure 6 As shown, when the rack bar 103 reaches near its displacement limit (see the dotted arrow), such as when the wheel 112 of the self-propelled vehicle is steered to near its steering limit, the end of the inner cavity forming body 130 contacts the rack housing 104, and the linear damper 120 begins to operate. In this case, during the operation of the linear damper 120, the end of the inner cavity forming body 130 may contact the rack housing 104 with a relatively weak force or with a relatively strong force.

[0090] First, when the end of the inner cavity forming body 130 contacts the rack housing 104 with a relatively weak force (low speed), as shown in FIG. Figure 7 As shown, the inner cavity forming body 130 slowly slides relative to the socket body 107 toward the stud body 108 (see the dotted arrow). Specifically, the flow control valve 140 displaces toward the cushioning material 123a within the inner cavity 121, overcoming the elastic force of the return elastic body 132. In this situation, the fluid 124 of the first flow control valve 150 flows from the large-diameter hole 157a of the second flow hole 157 of the second flow body 156 toward the small-diameter hole 157b.

[0091] However, in this case, since the flow control valve 140 slowly displaces within the inner cavity 121, the force pressing the second flow body 156 is smaller than the elastic force of the separation elastic body 159. Therefore, the second flow body 156 does not displace toward the first flow body 153 and is 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 through the second flow hole 157 of the second flow body 156 and the first flow hole 154 of the first flow body 153, respectively, toward the rear side in the displacement direction with slight flow resistance (see the dotted arrows).

[0092] 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 140 when the inner cavity forming body 130 slides and displaces against the elastic force of the return elastic body 132. Therefore, no flow of the fluid 124 occurs. Furthermore, the third flow control valve 170 is a valve that allows the flow of the fluid 124 in both the front and rear directions in the displacement direction of the flow control valve 140. Therefore, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 140 with minimal flow resistance.

[0093] Therefore, the flow control valve 140 is displaced toward the cushioning material 123a while generating a negligibly small damping force.

[0094] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the end of the inner cavity forming body 130 is separated from the rack housing 104, the inner cavity forming body 130 is displaced to its original position by the elastic force of the return elastic body 132 (see FIG. Figure 5 In this case, in the first flow control valve 150 , the fluid 124 flows from the first flow body 153 side and flows toward the second flow body 156 side.

[0095] In this case, the second flow body 156 is returned to its original position farthest 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. 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 with slight flow resistance through the first flow hole 154 of the first flow body 153 and the second flow hole 157 of the second flow body 156.

[0096] Furthermore, 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 cavity forming body 130 is slidably displaced by the elastic force of the return elastic body 132. Therefore, the fluid 124 flows with minimal flow resistance. Furthermore, the third flow control valve 170 is a valve that allows the fluid 124 to flow in both the front and rear directions in the displacement direction of the flow control valve 140. Therefore, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 140 with minimal flow resistance.

[0097] Therefore, the flow control valve 140 is displaced toward the cushioning material 123b while generating a negligibly small damping force. As a result, the inner cavity forming body 130 is slidably displaced toward the rack housing 104 at a faster displacement speed than before.

[0098] Next, when the end of the inner cavity forming body 130 contacts the rack housing 104 with a strong force (at high speed) (e.g., when the driver suddenly turns the wheel or the wheel 112 hits a curb), the inner cavity forming body 130 rapidly slides toward the stud body 108 relative to the socket body 107. In other words, the flow control valve 140 rapidly displaces toward the cushioning material 123a within the inner cavity 121, overcoming the elastic force of the return elastic body 132.

[0099] In this case, if Figure 8 As shown, the force of the fluid 124 pressing the second flow body 156 is greater than the elastic force of the separation 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. In this case, after the second flow body 156 begins to displace toward the first flow body 153 due to the pressing force of the fluid 124 acting on the step portion 157c and the tapered portion 157d of the small-diameter hole 157b, the pressing force of the fluid 124 also acts on the end of the large-diameter hole 157a, causing it to displace toward the first flow body 153.

[0100] Furthermore, in this case, the first aperture restricting portion 155 and the second aperture restricting portion 158 are formed at positions opposing the second flow hole 157 and the first flow hole 154, respectively, thereby blocking all of the second flow hole 157 and a portion of the first flow hole 154. Therefore, in the first flow control valve 150, when the flow control valve 140 is displaced toward the stud body 108, the fluid 124 does not flow (see the dashed arrow). Similarly, in this case, the second flow control valve 160 does not flow the fluid 124, as described above.

[0101] Furthermore, third flow control valve 170, of the flow control valves 140, is the only one that allows the flow of fluid 124, thus generating a significant flow resistance. Consequently, flow control valve 140 overcomes this significant flow resistance and displaces toward cushioning material 123a. This causes inner cavity forming body 130 to slide toward stud body 108, generating a significant damping force. In other words, direct-acting damper 120 can dampen the strong impact generated by rack bar 103.

[0102] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the end of the inner cavity forming body 130 is separated from the rack housing 104, the inner cavity forming body 130 is displaced to its original position by the elastic force of the return elastic body 132 in the same manner as described above (see FIG. Figure 5 That is, the inner cavity forming body 130 is displaced toward the cushioning material 123 b by the flow control valve 140 while generating a negligibly small damping force, and is rapidly slidably displaced toward the rack housing 104 .

[0103] Furthermore, the second flow body 156 is 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, returning to its original position. In this case, since the second aperture restricting portion 158 is formed at a position opposing a portion of the first flow hole 154, the second flow body 156 can guide a portion of the fluid 124 flowing from the first flow hole 154 into the second flow body accommodating portion 151 toward the second flow hole 157. Furthermore, in the first flow control valve 150, as described above, the fluid 124 on the forward 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, toward the rearward side in the displacement direction with minimal flow resistance.

[0104] It can also be understood from the description of the above working method that according to the above-mentioned first embodiment, since the direct-acting damper 120 is provided with the socket body 107 as a relative displacement body in a state of penetrating the inner cavity forming body 130 formed into a cylindrical shape, the direct-acting damper 120 can be provided not in the axial direction of the rack ball joint mechanism 106 extending into an axis shape in the steering device 100, which is the installation object of the direct-acting damper 120, but in the radial outside of the rack ball joint mechanism 106, which can avoid the large-scale (mainly elongated) device structure of the steering device 100 and can expand the types of steering devices that can be installed.

[0105] <Second embodiment>

[0106] Next, refer to Figures 9 to 13A second embodiment of a steering system including a flow control valve and a direct-acting damper according to the present invention will be described. The steering system 200 in this second embodiment differs from the first embodiment in that a direct-acting damper 210, equivalent to the direct-acting damper 120 in the first embodiment, is assembled to the rack housing 104 rather than the socket body 107. Therefore, the description of the steering system 200 in this second embodiment will focus on the parts that differ from the steering system 200 in the first embodiment, and descriptions of common or corresponding parts between the two embodiments will be omitted as appropriate. Furthermore, in the description of this second embodiment, components identical to those in the first embodiment are denoted by the same reference numerals as in the first embodiment.

[0107] (Structure of Steering Device 200)

[0108] The steering device 200 has a cylindrical linear motion damper 210 mounted on the front end of a cylindrical rack housing 104. A dust cover 201 is mounted to cover the linear motion damper 210. The dust cover 201 is a component for preventing contamination of the linear motion damper 210 and is formed by forming an elastic material such as rubber into a cylindrical shape.

[0109] The rack rod 103 extends through the interior of the cylindrical linear damper 210, which is attached to the front end of the rack housing 104. Furthermore, a rack ball joint mechanism 106 is attached to the front end of the rack rod 103. In this case, the socket body 107 attached to the rack rod 103 is formed so that its outer periphery protrudes from the outer periphery of the rack rod 103 in a flange-like shape and is arranged to face the end of the relative displacement body 230.

[0110] The damper 210 includes an inner cavity forming body 211. This inner cavity forming body 211 is a component used to form an inner cavity 217 and to attach the linear damper 210 to the rack housing 104. It is formed by forming a metal material into a cylindrical shape. Specifically, the inner cavity forming body 211 corresponds to the inner cavity forming body 130 described in the first embodiment. An externally threaded portion 211a for threaded engagement with the rack housing 104 is formed on one end (left side in the figure) of the outer periphery of the inner cavity forming body 211. An oil supply port 212 and an accumulator housing 213 are formed on the other end (right side in the figure).

[0111] The oil supply port 212 is a flow path for injecting and discharging the fluid 124 into the inner cavity 217 and is openably and closably sealed by a plug. The accumulator housing 213 and the accumulator 214 correspond to the accumulator housing 135 and the accumulator 136 in the first embodiment, respectively. Furthermore, the inner cavity-forming body 211 has wall-forming bodies 215 and 216 threadedly engaged at both ends, forming a cylindrical inner cavity 217 between these two wall-forming bodies 215 and 216.

[0112] Wall-forming bodies 215 and 216 are components used to form the left and right walls of the inner cavity 217 (as shown). They are formed by shaping a metal material into an annular shape. Specifically, wall-forming bodies 215 and 216 correspond to wall-forming body 122 in the first embodiment described above. Therefore, inner cavity 217 is formed into an annular cylindrical shape extending axially inside inner cavity-forming body 211 between the relative displacement body 230 (described later). Of these wall-forming bodies 215 and 216, wall-forming body 216 on the side of intermediate connecting body 105 has a restoring elastic body 218 embedded in its outer periphery.

[0113] The resetting elastic body 218 is a component for elastically pressing the flow control valve 240 against the right end portion shown in the figure within the inner cavity 217, and is composed of a metal coil spring. That is, the resetting elastic body 218 corresponds to the resetting elastic body 132 in the first embodiment described above. The end portion of one side (the left side shown in the figure) of the resetting elastic body 218 elastically presses the wall forming body 216, and the end portion of the other side (the right side shown in the figure) elastically presses the relative displacement body 230 via the support plate 218a. In other words, the resetting elastic body 218 imparts elastic force to the inner cavity forming body 211 and the socket body 107, respectively, so that the flow control valve 240 is located on the side (the ball retaining portion 107a side) where the external force acts on the direct-acting damper 210.

[0114] In addition, the wall forming bodies 215 and 216 are respectively provided with cushioning materials 221a and 221b, sliding bushings 222a and 222b, sealing rings 223a and 223b and dustproof seals 224a and 224b corresponding to the cushioning materials 123a and 123b, sliding bushings 125a and 125b, sealing rings 126a and 126b and dustproof seals 134 in the above-mentioned first embodiment.

[0115] The relative displacement body 230 is a component that covers the radially inner side of the inner cavity 217 and forms the flow control valve 240. It is constructed by forming a metal material into a cylindrical shape. Specifically, the relative displacement body 230 corresponds to the socket body 107 in the first embodiment described above. The relative displacement body 230 is formed into a cylindrical shape that slidably fits onto the inner circumferential surfaces of the wall-forming bodies 215 and 216 via sliding bushings 222a and 222b. In this case, the relative displacement body 230 is formed to a length that protrudes from each end of the wall-forming bodies 215 and 216. Furthermore, the inner diameter of the relative displacement body 230 is formed to a size sufficient for the rack bar 103 to pass through.

[0116] The support plate 218a is fixedly mounted on one end (the right side in the figure) of the outer periphery of the relative displacement body 230. A fixed sleeve 231 and a flow control valve 240 are mounted from the other end (the left side in the figure) to the axial center. The fixed sleeve 231 is a component used to press and secure the flow control valve 240, which is fitted onto the smaller diameter portion formed on the outer periphery of the relative displacement body 230, to the larger diameter portion formed on the outer periphery of the relative displacement body 230. It is formed of a cylindrical metal material. The fixed sleeve 231 is integrally assembled with the outer periphery of the relative displacement body 230 and slides relative to the wall-forming body 215 via a sliding bushing 222a.

[0117] The flow control valve 240 is a device for controlling the flow of the fluid 124 within the inner chamber 217 by restricting the flow of the fluid 124 and thereby generating a damping force in the direct-acting damper 210. This valve corresponds to the flow control valve 140 in the first embodiment described above. The flow control valve 240 mainly includes a valve support 241, a first flow control valve 150, a second flow control valve 160, and a third flow control valve 170.

[0118] The valve support body 241 is a component that forms the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170. It is formed by forming a metal material into a flat circular ring shape. Specifically, the valve support body 241 is a separate component from the relative displacement body 230 and is integrally attached to the relative displacement body 230 via a fixing sleeve 231. A sealing ring 242, corresponding to the sealing ring 142 in the first embodiment, is embedded in the outer periphery of the valve support body 241.

[0119] The first flow control valve 150, the second flow control valve 160, and the third flow control valve 170 are configured similarly to those in the above-described embodiment, and therefore their description will be omitted. Furthermore, the flow control valve 240 is mounted on 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 opening toward the buffer material 221a (left side in the figure).

[0120] (Operation of Steering Device 200)

[0121] Next, the operation of the steering device 200 thus configured will be described. Similar to the steering device 100 in the above embodiment, the steering device 200 activates the linear damper 210 when the rack bar 103 is displaced near the left and right displacement limits relative to the pinion 102a.

[0122] Specifically, when the rack bar 103 does not reach the displacement limit, such as when the wheel 112 of the self-propelled vehicle is not steered to the limit of steering, the socket body 107 does not collide with the relative displacement body 230, and thus the linear damper 210 does not operate (see FIG. Figure 9 In this case, the flow control valve 240 of the direct-acting damper 210 is pressed against the wall-forming body 216 via the buffer material 221b within the inner cavity 217 by the elastic force of the return elastic body 218. In other words, the relative displacement body 230 is maintained in a state where it is elastically positioned closest to the socket body 107 within the inner cavity 217.

[0123] Furthermore, the first flow control valve 150 maintains the second flow body 156 positioned 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.

[0124] Next, if Figure 11 As shown, when the rack bar 103 reaches near its displacement limit, such as when the wheel 112 of the self-propelled vehicle is steered near its steering limit, the socket body 107 contacts the end of the relative displacement body 230 and the linear damper 210 starts to operate.

[0125] First, when the socket body 107 contacts the end of the relative displacement body 230 with a relatively weak force (low speed), as shown in FIG. Figure 12 As shown, the relative displacement body 230 slowly slides relative to the inner cavity forming body 211 toward the rack housing 104. Specifically, the flow control valve 240 displaces toward the cushioning material 221a (left side in the figure) within the inner cavity 217, overcoming the elastic force of the return elastic body 218. In this situation, the fluid 124 in the first flow control valve 150 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.

[0126] However, in this case, since the flow control valve 240 slowly displaces within the inner cavity 217, the force pressing the second flow body 156 is smaller than the elastic force of the separation elastic body 159. Therefore, the second flow body 156 does not displace toward the first flow body 153 and is 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 through the second flow hole 157 of the second flow body 156 and the first flow hole 154 of the first flow body 153, respectively, toward the rear side in the displacement direction with slight flow resistance.

[0127] 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 overcomes the elastic force of the return elastic body 218 and slides and displaces. Therefore, no flow of the fluid 124 occurs. Furthermore, the third flow control valve 170 is a valve that allows the flow of the fluid 124 in both the front and rear directions in the displacement direction of the flow control valve 240. Therefore, the fluid 124 flows from the front side to the rear side in the displacement direction of the flow control valve 240 with minimal flow resistance.

[0128] Therefore, the flow control valve 240 is displaced toward the cushioning material 123 a while generating a negligibly small damping force.

[0129] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and separated from the socket body 107 from 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 as in the first embodiment (see FIG. Figure 9 That is, the flow control valve 240 displaces toward the cushioning material 221b while generating a negligibly small damping force. As a result, the relative displacement body 230 slides toward the socket body 107 at a faster displacement speed than before.

[0130] Next, when the socket body 107 contacts the end of the relative displacement body 230 with a strong force (high speed), as shown in FIG. Figure 13 As shown, the relative displacement body 230 rapidly slides toward the rack housing 104 relative to the inner cavity forming body 211. That is, the flow control valve 240 rapidly displaces toward the buffer material 221a in the inner cavity 217 against the elastic force of the return elastic body 218.

[0131] In this case, the force exerted by fluid 124 on second flow element 156 is greater than the elastic force of separation elastic member 159, causing first flow control valve 150 to displace toward first flow element 153 and be pressed against it. Furthermore, in this case, first aperture restriction 155 and second aperture restriction 158 are formed at positions opposing second flow hole 157 and first flow hole 154, respectively, thereby blocking all of second flow hole 157 and a portion of first flow hole 154, respectively. Therefore, in first flow control valve 150, when flow control valve 240 is displaced toward rack housing 104, fluid 124 ceases to flow (see dashed arrow). Similarly, in this case, fluid 124 ceases to flow through second flow control valve 160, as described above.

[0132] Furthermore, the third flow control valve 170, of the flow control valves 240, is the only one that allows the fluid 124 to flow, thus generating a very high flow resistance. Consequently, the flow control valve 240 overcomes this very high flow resistance and displaces toward the cushioning material 221a. This causes the relative displacement body 230 to slide toward the rack housing 104, generating a significant damping force. In other words, the direct-acting damper 210 can dampen the strong impact generated by the rack bar 103.

[0133] Thereafter, when the rack bar 103 is displaced toward the knuckle arm 111 and the socket body 107 is separated from 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 described above (see FIG. Figure 9 That is, the relative displacement body 230 is displaced toward the cushioning material 221 b by generating a negligibly small damping force through the flow control valve 240 , thereby rapidly slidingly displaced toward the socket body 107 .

[0134] And, when implementing the present invention, it is not limited to above-mentioned each embodiment, as long as do not depart from the purpose of the present invention, just can carry out various changes.In addition, in the description of each modification, to the part identical with above-mentioned embodiment, mark the same figure mark and omit repeated description.

[0135] For example, in the above-described embodiments, the direct-acting dampers 120 and 210 are configured such that the flow control valves 140 and 240 are disposed within the inner cavities 121 and 217. Thus, the direct-acting dampers 120 and 210 can be configured to be more compact by disposing the flow control valves 140 and 240 within the inner cavities 121 and 217. However, the direct-acting dampers 120 and 210 can also be configured such that part or all of the flow control valves 140 and 240 are disposed outside the inner cavities 121 and 217.

[0136] For example, in Figure 14 and Figure 15 , a direct-acting damper 300 is shown in which the inner cavity forming body 211 of the direct-acting damper 210 of the second embodiment is equipped with a first flow control valve 150. This direct-acting damper 300 has a bypass flow path 301 formed within the inner cavity forming body 211, and includes the first flow control valve 150 on the outer periphery of the inner cavity forming body 211. The first flow control valve 150, connected to the bypass flow path 301, constitutes a portion of the flow control valve 310. 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 cavity 217 in the axial direction, which are bounded by the flow control valve 310.

[0137] The flow control valve 310 is constructed in the same manner as the flow control valve 240 of the second embodiment described above, with the first flow control valve 150 being relocated to the inner cavity forming body 211 and further comprising a second flow control valve 160 and a third flow control valve 170. The first flow control valve 150 controls whether the fluid 124 flowing through the bypass flow path 301 can flow.

[0138] In this case, the first flow control valve 150 has a second flow body housing portion 151 formed within the inner cavity forming body 211, communicating with the inner cavity 217. The second flow body housing portion 151 houses a second flow body 156 and a separating elastic member 159. An eccentric ring member (a component having a through hole, functioning as the first flow hole 154, formed eccentrically from the center of a circular plate serving as the first aperture restricting portion 155) constituting the first flow body 153 is embedded in the second flow body housing portion 151 on the side opposite the inner cavity 217. The eccentric ring member 153 communicates with the bypass flow path 301 via the first flow body 153. Furthermore, a bypass flow path 301 is formed extending from the portion of the inner cavity forming body 211 that faces the second flow body housing portion 151 across the bypass passage 301, communicating with the exterior of the inner cavity forming body 211. This extended bypass flow path 301 is blocked by a plug 302.

[0139] That is, the direct-acting damper 300 is configured such that a portion of the flow control valve 310, namely the second flow control valve 160 and the third flow control valve 170, is disposed within the inner cavity 217, and the other portion, namely the first flow control valve 150, is disposed outside the inner cavity 217. The direct-acting damper 300 thus configured operates in the same manner as the direct-acting damper 210 in the second embodiment described above. Figure 14 In the figure, the rack bar 103 and the rack housing 104 are omitted.

[0140] In this manner, the direct-acting damper 300 can ensure a large capacity of the inner cavity 217 by locating at least a portion or all of the flow control valve 310 outside the inner cavity 217. Furthermore, the direct-acting damper 300 can expose the first flow control valve 150 by removing the plug 302 in the inner cavity forming body 211, thereby improving maintainability.

[0141] In the above-described embodiments, the direct-acting dampers 120, 210, and 300 are each configured with a return elastic body 132 or 218. However, if it is not necessary to constantly press the flow control valve 140, 240, or 310 toward one side of the inner cavity 121 or 217 (the side on which the external force acts on the direct-acting damper 120, 210, or 300), the direct-acting damper 120, 210, or 300 may be configured without the return elastic body 132 or 218.

[0142] In addition, in the first embodiment, the socket body 107 as a relatively displaceable body is formed into a shaft shape. Figure 16 As shown, the socket body 107 as a relative displacement body can also be formed into a cylindrical shape. In this case, the steering device 100 forms an external thread on the front end of the rack rod 103 and an internal thread in the through hole of the socket body 107, so that the rack rod 103 and the socket body 107 can be connected by threaded engagement.

[0143] In the above-described embodiments, the first flow control valve 150 is configured such that the second aperture restriction 158 of the second flow body 156 partially blocks the first flow hole 154 of the first flow body 153, and the first aperture restriction 155 of the first flow body 153 completely blocks the second flow hole 157 of the second flow body 156. However, the first flow control valve 150 may be configured to block at least a portion of at least one of the first flow hole 154 and the second flow hole 157.

[0144] So, for example Figure 17 As shown, the first flow control valve 150 can also be configured to completely block both the first flow hole 154 and the second flow hole 157. In addition, the first flow control valve 150 can also be configured to block a portion of both the first flow hole 154 and the second flow hole 157. In this case, for example, Figure 18 As shown, the first flow control valve 150 can also be configured so that a portion of the first flow hole 154 and a portion of the second flow hole 157 overlap each other when the second flow body 156 is in close contact with the first flow body 153, thereby ensuring the flow of the fluid 124. Thus, the flow control valves 140 and 240 can be configured without the third flow control valve 170.

[0145] In addition, 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 and not block the other. Figure 19 As shown, the first flow control valve 150 can have a first aperture restriction portion 155 formed in the bottom portion of the second flow body housing 151, opposite the small-diameter aperture 157b, that projects in a columnar shape toward the small-diameter aperture 157b (second flow hole 157). In this case, the second aperture restriction portion 158 of the second flow body 156 is omitted. Thus, the first flow control valve 150 can block only the second flow hole 157 by abutting the second flow body 156 against the first aperture restriction portion 155.

[0146] In addition, for example Figure 20 and Figure 21 As shown in each example, the first flow control valve 150 can also include a columnar second aperture restrictor 158 protruding toward the first flow hole 154 in the portion of the second flow body 156 that faces the first flow hole 154, thereby blocking only the first flow hole 154. In this case, the first aperture restrictor 155 in the first flow body 153 can be omitted. Furthermore, in this case, the columnar first aperture restrictor 155 and / or second aperture restrictor 158 can be inserted into the small-diameter hole 157b (second flow hole 157) and / or the first flow hole 154, thereby blocking each hole.

[0147] In the above-described embodiments, the second flow hole 157 is composed of two holes: a large-diameter hole 157a and a small-diameter hole 157b. However, the second flow hole 157 may be composed of a single 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. Furthermore, the second flow hole 157 has a tapered portion 157d formed at the opening of the small-diameter hole 157b on the side opposite the first flow element 153. This facilitates the flow of the fluid 124 into the second flow hole 157, stabilizing the operation of the first flow control valve 150. Furthermore, the first flow control valve 150 facilitates the flow of the fluid 124 into the second flow hole 157, thereby increasing the flow rate. Therefore, the tapered portion 157d exerts a strong pressure from the fluid 124, facilitating displacement of the second flow element 156 toward the first flow element 153. However, the second flow hole 157 may also be formed straight without the tapered shape. Furthermore, the first flow hole 154 may be composed of a plurality of holes that are different from each other, and the opening of the hole may be tapered.

[0148] Furthermore, in each of the above-described embodiments, the flow control valves 140, 240, and 310 are configured to include multiple flow control valves, namely, the first flow control valve 150, the second flow control valve 160, and the third flow control valve 170. The second flow control valve 160 can increase the displacement speed of the flow control valves 140 and 240 during their return displacement. Furthermore, the third flow control valve 170 can ensure the flow of the fluid 124 while the second flow element 156 and the first flow element 153 are in close contact, completely blocking the flow of the fluid 124.

[0149] However, the flow control valve 140, 240, or 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 damper 120, 210, or 300. In the above case, the second flow control valve 160 may or may not be included depending on the specifications of the direct-acting damper 120, 210, or 300.

[0150] In the above-described embodiments, the direct-acting dampers 120, 210, and 300 are applied to the steering devices 100 and 200. However, the direct-acting dampers 120, 210, and 300 can be attached to devices or appliances other than the steering devices 100 and 200, specifically, suspension mechanisms, seat tilt mechanisms, door opening and closing mechanisms, mechanical devices other than self-propelled vehicles, motor devices, appliances, or furniture.

[0151] Description of Reference Numerals

[0152] 100…steering device; 101…steering wheel; 102…steering shaft; 102a…pinion gear; 103…rack rod; 103a…rack gear; 104…rack housing; 105…intermediate connecting body; 106…rack ball joint mechanism; 107…socket body (relative displacement body); 107a…ball retaining portion; 107b…external thread portion; 108…stud body; 108a…ball portion; 110…tie rod; 111…steering knuckle arm; 112…wheel; 120…linear damper; 121…inner cavity; 122…wall forming body; 123a, 123 b…buffer material; 124…fluid; 125a, 125b…sliding bushing; 126a, 126b…sealing ring; 130…inner cavity forming body; 131…elastic body retaining portion; 132…resetting elastic body; 133…dust cover; 134…dust seal; 135…accumulator housing; 136…accumulator; 140…circulation control valve; 141…valve support; 142…sealing ring; 150…first circulation control valve; 151…second circulation body housing; 152…anti-slip ring; 153…first circulation body; 154…first circulation hole; 1 55…first aperture restriction portion; 156…second flow element; 156a…large diameter portion; 156b…small diameter portion; 157…second flow hole; 157a…large diameter hole; 157b…small diameter hole; 157c…stepped portion; 157d…tapered portion; 158…second aperture restriction portion; 159…separation elastic body; 160…second flow control valve; 170…third flow control valve; 200…steering mechanism; 201…dust cover; 210…linear damper; 211…inner cavity forming body; 211a…externally threaded portion; 212…oil supply port; 213…energy storage Device housing portion; 214…accumulator; 215, 216…wall forming body; 217…inner cavity; 218…reset elastic body; 218a…support plate; 221a, 221b…cushion material; 222a, 222b…sliding bushing; 223a, 223b…sealing ring; 224a, 224b…dustproof seal; 230…relative displacement body; 231…fixing sleeve; 240…circulation control valve; 241…valve supporting body; 242…sealing ring; 300…direct-acting damper; 301…bypass flow path; 302…plug; 310…circulation control valve.

Claims

1. A linear damper comprising an inner cavity forming body having an inner cavity for liquid-tightly accommodating a fluid, wherein an external force applied to the fluid is attenuated by restricting the flow of the fluid, characterized in that: have: a relative displacement body that is relatively displaced relative to the inner cavity forming body; and a flow control valve provided on at least one of the inner cavity forming body and the relative displacement body, and restricting the flow of the fluid; The inner cavity forming body is formed into a cylindrical shape and the inner cavity is formed inside the portion formed into the cylindrical shape. The relative displacement body passes through the inner cavity forming body and is slidably embedded in the inner cavity forming body. The linear motion damper is not provided in the axial direction of a portion extending in an axial shape in an object to which the damper is to be mounted, but is provided outside the portion.

2. The direct-acting damper according to claim 1, characterized in that A return elastic body is further provided, which applies elastic force to at least one of the inner cavity forming body and the relative displacement body so that the flow control valve is located on the side where the external force acts on the linear damper.

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

4. The linear damper according to any one of claims 1 to 3, wherein: The flow control valve is provided at least in the inner cavity forming body.

5. The linear damper according to any one of claims 1 to 4, characterized in that: The flow control valve is at least provided on the relative displacement body.

6. The linear damper according to any one of claims 1 to 5, characterized in that: The flow control valve is at least arranged outside the inner cavity.

7. A steering device comprising: A steering shaft, formed by extending into a rod shape and rotated by operation of the steering wheel; A rack rod is formed by extending into a rod shape and converting the rotational motion of the steering shaft into reciprocating motion in the axial direction for transmission; an intermediate connecting body connected to both ends of the rack bar and directly or indirectly connected to wheels to be steered with respect to the both ends; and a rack housing, covering the rack rod, The steering device is characterized in that A linear damper according to any one of claims 1 to 6, The linear damper is provided between the rack housing and the rack bar or the intermediate connecting body to attenuate impact from the wheel.

8. The steering device according to claim 7, characterized in that The relative displacement body is formed on the intermediate connecting body, The inner cavity forming body is formed at a position where it comes into contact with or is separated from the rack housing by the reciprocating motion of the rack bar.

9. The steering device according to claim 7, characterized in that The inner cavity forming body is formed at the end of the rack housing. The relative displacement body has the rack bar or the intermediate connecting body passing therethrough, and is formed at a position where the relative displacement body contacts or separates from the rack bar or the intermediate connecting body due to the reciprocating motion of the rack bar.

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