Linear damper and steering device

Abstract

To provide a linear motion damper which can inhibit occurrence of large collision noise or impact shock when a large load rapidly acts thereon, and to provide a steering device including the linear motion damper.SOLUTION: A steering device 100 includes a linear motion damper 120 between a rack bar 103 and a rack end 106. In the linear motion damper 120, a relative displacement body 140 is provided within an internal chamber formation body 121 formed in a cylindrical shape so as to be displaced in a reciprocating manner. In the internal chamber formation body 121, a first inner chamber 125a and a second inner chamber 125b are respectively formed at both sides of a valve support part 123 supporting a first circulation control valve 127 and a second circulation control valve 128. Further, a butted part 131 is provided at an end, which faces a rack housing 104, in the internal chamber formation body 121. The butted part 131 is formed by forming an elastic body, which may elastically deform, in an annular shape.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Conventionally, there are linear dampers that damp kinetic energy in linear motion. For example, as shown in the following Patent Document 1, the inventor of the present application has proposed a linear damper that reduces the impact load generated between a rack end and a rack housing by restricting the flow of fluid to a rack end that is displaced relative to the rack housing in a steering device of a self-propelled vehicle and the rack housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Application No. 2020-096430 Summary of the Invention

[0004] However, the linear damper disclosed in Patent Document 1 has a problem in that when the rack end suddenly approaches the rack housing and the linear damper collides with the rack housing, a loud collision noise is generated and a large, instantaneous shock is applied to the steering device.

[0005] The present invention has been made to address the above-mentioned problems, and its object is to provide a linear damper that can suppress the generation of loud collision noise or impact even when a large load is suddenly applied, and a steering device equipped with this linear damper.

[0006] In order to achieve the above object, the present invention is characterized in that the linear damper comprises an inner chamber forming body formed in a cylindrical shape and having an inner chamber for liquid-tightly accommodating a fluid inside the cylindrical portion, a relative displacement body slidably fitted into the inner chamber forming body and displaced relative 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 to allow the fluid to flow while restricting the flow of the fluid, the linear damper being disposed between two objects to be attached which are linearly displaced relative to each other and attenuating an external force received due to the relative displacement by restricting the flow of the fluid, wherein one of the inner chamber forming body and the relative displacement body has an attachment portion attached to one of the two objects to be attached, and the other of the inner chamber forming body and the relative displacement body has an abutment portion against which the other of the two objects to be attached abuts, the abutment portion being configured to include an elastic body that elastically receives the abutment of the other of the two objects to be attached. And, The inner chamber forming body and the relative displacement body each have a displacement limit determining portion that determines one displacement limit and the other displacement limit within the range of relative displacement when they abut against each other due to relative displacement, and at least one of the displacement limit determining portions is configured to include an elastic body.

[0007] According to this, since the abutment portion of the linear damper is configured to include an elastic material, it is possible to prevent the generation of loud collision noise or impact even when the abutment portion collides with the mounting object opposite the abutment portion of one of the two mounting objects on which the linear damper is installed and a large load is suddenly applied. Further, according to the present invention,The linear damper is configured such that at least one of the displacement limit defining parts of one displacement limit and the other displacement limit in the relative displacement range of the relative displacement body includes an elastic body. Therefore, by providing a displacement limit defining part including an elastic body at one displacement limit position in the relative displacement range of the relative displacement body, the linear damper can reduce the impact when the relative displacement body reaches the one displacement limit position, and can also attenuate the external force even if an external force is further applied. Furthermore, by providing a displacement limit defining part including an elastic body at the other displacement limit position in the relative displacement range of the relative displacement body, the linear damper can reduce the impact when the relative displacement body reaches the other displacement limit position, and can also attenuate the external force even if an external force is further applied. In other words, the linear damper can attenuate the impact or external force when the relative displacement body receives an external force and reaches a displacement limit position and / or when the relative displacement body reaches a displacement limit position of its original position before receiving the external force.

[0008] In order to achieve the above object, the present invention is characterized in that the linear damper comprises an inner chamber forming body formed in a cylindrical shape and having an inner chamber for liquid-tightly accommodating a fluid inside the cylindrical portion, a relative displacement body slidably fitted into the inner chamber forming body and displaced relative 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 to allow the fluid to flow while restricting the flow of the fluid, the linear damper being disposed between two objects to be attached which are linearly displaced relative to each other and attenuating an external force received due to the relative displacement by restricting the flow of the fluid, wherein one of the inner chamber forming body and the relative displacement body has an attachment portion attached to one of the two objects to be attached, and the other of the inner chamber forming body and the relative displacement body has an abutment portion against which the other of the two objects to be attached abuts, the abutment portion being configured to include an elastic body that elastically receives the abutment of the other of the two objects to be attached. And, The relative displacement body is provided with a volume change compensation device that compensates for a volume change of the fluid in the internal chamber.

[0009] According to this, since the abutment portion of the linear damper is configured to include an elastic material, it is possible to prevent the generation of loud collision noise or impact even when the abutment portion collides with the mounting object opposite the abutment portion of one of the two mounting objects on which the linear damper is installed and a large load is suddenly applied. Further, according to the present invention, Since the linear damper includes a volume change compensation device in which the relative displacement body compensates for the volume change of the fluid in the inner chamber, the linear damper can have a compact structure.

[0010] Another feature of the present invention is that the linear damper includes a return elastic body that applies an elastic force to at least one of the inner chamber forming body and the relative displacement body to elastically press the inner chamber forming body or the relative displacement body that does not have an abutment portion toward a side that moves the inner chamber forming body or the relative displacement body away from the abutment portion. According to this, the linear damper applies an elastic force to the return elastic body to elastically displace the inner chamber forming body or the relative displacement body that does not have an abutment portion so as to move the inner chamber forming body or the relative displacement body away from the abutment portion. As a result, when no external force is applied to relatively displace the inner chamber forming body and the relative displacement body, the linear damper according to the present invention can always position the inner chamber forming body or the relative displacement body that does not have an abutment portion at the end on the side that moves away from the abutment portion in the relative displacement region, that is, at the operation start position for exerting the damping function of the flow control valve, thereby maximizing the stroke of the relative displacement body.

[0011] Another feature of the present invention is that in the linear damper, the abutment portion is formed in an annular shape. According to this, since the abutment portion of the linear damper is formed in an annular shape, it is possible to position all or part of the components of the linear damper or at least one of the two mounting objects on which the linear damper is installed inside the abutment portion, thereby expanding the variety of configurations, mounting objects, and installation methods of the linear damper.

[0012] Another feature of the present invention is that in the linear damper, the abutting portion is made of an elastomer material.

[0013] According to this, in the linear damper, since the abutment portion is made of an elastomer material, it is possible to more effectively suppress the occurrence of collision noise or impact compared to a case in which the abutment portion is made of a metal material such as a coil spring. Here, the elastomer material is a rubber material or a resin material that can elastically absorb the impact when the abutment portion collides with an object, and more specifically, there is a thermosetting elastomer material (e.g., vulcanized rubber, urethane rubber, silicone rubber, fluororubber, etc.) and a thermoplastic elastomer material (e.g., styrene-based, olefin-based, PVC-based, urethane-based, or amide-based resin, etc.). It is to be noted that the abutment portion can be made of a material other than an elastomer material, for example, a metal leaf spring or coil spring.

[0014] Another feature of the present invention is that in the linear damper, the abutting portion is formed with at least one of a bottomed hole and a through hole.

[0015] According to another feature of the present invention configured in this manner, since the abutment portion of the linear damper is formed with at least one of a bottomed hole and a through hole, the impact damping force by the abutment portion can be adjusted by the number, size or position of the bottomed holes or through holes.

[0016] Furthermore, the present invention can be embodied not only as an invention of a linear damper, but also as an invention of a steering device equipped with this linear damper.

[0017] Specifically, the steering device includes a steering shaft that is formed to extend in a rod-like shape and rotates by operating a steering wheel, a rack bar that is formed to extend in a rod-like shape and converts the rotational motion of the steering shaft into a reciprocating motion in the axial direction and transmits the motion, intermediate connectors that are connected to both ends of the rack bar and directly or indirectly connect wheels to be steered to the both ends, and a rack housing that covers the rack bar. 1 or claims6 The linear damper is provided between the rack housing and the rack bar or the intermediate connector to attenuate impact from the wheels and / or impact due to inertia force from the steering shaft side. In this way, the steering device according to the present invention can be expected to have the same effects as the linear damper described above.

[0018] In this case, in the steering device, the relative displacement body may be connected to the intermediate connector, and the inner chamber forming body may be formed so as to come into contact with or be separated from the rack housing by the reciprocating motion of the rack bar.

[0019] According to this, in the steering device of the present invention, the relative displacement body is connected to the intermediate connecting body, the inner chamber forming body is formed so as to contact or move away from the rack housing due to the reciprocating motion of the rack bar, and the damper is provided on an intermediate connecting body such as a tie rod or a rack end, making it easy to perform maintenance or replacement of the linear damper.

[0020] In this case, in the steering device, the inner chamber forming body is connected to an end of the rack housing, and the relative displacement body has a rack bar or an intermediate connector passing through it, and the rack bar or the intermediate connector can be formed to come into contact with or separate from the relative displacement body due to the reciprocating motion of the rack bar.

[0021] According to this, in the steering device according to the present invention, the inner chamber forming body is formed at the end of the rack housing, and the relative displacement body is formed so that the rack bar or intermediate connector (tie rod or rack end, etc.) penetrates inside the relative displacement body and the rack bar or tie rod comes into contact with or separates from the relative displacement body due to the reciprocating motion of the rack bar. As a result, in the steering device according to the present invention, since the linear damper is provided in the rack housing, it is possible to reduce the weight of the rack bar or intermediate connector (tie rod or rack end, etc.).

[0022] In order to achieve the above object, the present invention is characterized by: A steering device including a steering shaft that is formed to extend like a rod and rotates by operating a steering wheel, a rack bar that is formed to extend like a rod and converts the rotational motion of the steering shaft into a reciprocating motion in the axial direction and transmits the motion, intermediate connectors that are connected to both ends of the rack bar and directly or indirectly connect wheels to be steered to the both ends, and a rack housing that covers the rack bar, The linear damper is provided with an inner chamber forming body formed in a cylindrical shape and having an inner chamber for liquid-tightly accommodating a fluid inside the cylindrical portion, a relative displacement body slidably fitted into the inner chamber forming body and displaced relative 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 to allow the fluid to flow while restricting the flow of the fluid, and is disposed between two attachment objects which are linearly displaced relative to each other, thereby attenuating an external force received due to the relative displacement by restricting the flow of the fluid, wherein one of the inner chamber forming body and the relative displacement body has an attachment portion attached to one of the two attachment objects, and the other of the inner chamber forming body and the relative displacement body has an abutment portion against which the other of the two attachment objects abuts, and the abutment portion is configured to include an elastic body that elastically receives the abutment of the other of the two attachment objects. The linear damper is provided between the rack housing and the rack bar or intermediate connector to attenuate impact from the wheels and / or impact due to inertia force from the steering shaft side. death, The inner chamber forming body is connected to an end of the rack housing, and the relative displacement body has a rack bar or an intermediate connector passing therethrough, and is formed so that the rack bar or the intermediate connector comes into contact with or separates from the inner chamber forming body due to the reciprocating motion of the rack bar. It is because .

[0023] According to this, The steering device according to the present invention Since the abutment portion of the linear damper is configured to include an elastic material, it is possible to prevent the generation of loud collision noise or impact even when the abutment portion collides with the opposite mounting object of the two mounting objects on which the linear damper is installed and a large load is suddenly applied thereto. therefore, The steering device according to the present invention is expected to have the same operational effects as the linear damper described above. Further, according to the present invention,The inner chamber forming body is formed at an end of the rack housing, and the relative displacement body is formed so that the rack bar or intermediate connector (such as a tie rod or a rack end) penetrates through the inside of the relative displacement body and the rack bar or the tie rod comes into contact with or separates from the rack housing due to the reciprocating motion of the rack bar. As a result, in the steering device according to the present invention, the linear damper is provided in the rack housing, so that the weight of the rack bar or intermediate connector (such as a tie rod or a rack end) can be reduced. [Brief description of the drawings]

[0026] [Figure 1] 1 is an explanatory diagram that illustrates a schematic overview of an overall configuration of a steering device according to an embodiment of the present invention; [Diagram 2] 2 is a perspective view showing the outline of the external configuration of a linear damper constituting the steering device shown in FIG. 1. [Diagram 3] 3 is a front view showing the outline of the external configuration of the linear damper shown in FIG. 2. [Figure 4] 4 is a cross-sectional view showing an outline of the internal configuration of the linear damper as seen from line 4-4 shown in FIG. [Diagram 5] 5 is a cross-sectional view showing a state at the moment when an inner chamber forming body comes into contact with a rack housing in the linear damper shown in FIG. 4. [Figure 6] 5 is a cross-sectional view showing a state in which an inner chamber forming body is pressed toward a rack housing in the linear damper shown in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment of a steering device equipped with a linear damper according to the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic overview of the overall configuration of a steering device 100 according to the embodiment of the present invention. FIG. 2 is a perspective view showing an overview of the external configuration of a linear damper 120 constituting the steering device 100 shown in FIG. 1. FIG. 3 is a front view showing an overview of the external configuration of the linear damper 120 shown in FIG. 2. FIG. 4 is a cross-sectional view showing an overview of the internal configuration of the linear damper 120 as viewed from line 4-4 shown in FIG. 3.

[0028] The steering device 100 is a mechanical device for steering two front wheels (or rear wheels) of a four-wheeled self-propelled vehicle (not shown) in the left and right directions.

[0029] (Configuration of steering device 100) The steering device 100 includes a steering wheel 101. The steering wheel 101 is an operator (i.e., a handle) that allows a driver of a self-propelled vehicle to manually control the traveling direction, and is made of a resin or metal material formed into an annular shape. A steering shaft 102 is connected to the steering wheel 101.

[0030] The steering shaft 102 is a rod-shaped component that rotates about an axis in response to clockwise or counterclockwise rotation of the steering wheel 101, and is configured by connecting one or more metal rod bodies via universal joints, etc. The steering shaft 102 has the steering wheel 101 connected to one end, and a pinion gear 102a formed at the other end and connected to a rack bar 103.

[0031] The rack bar 103 is a component formed in a rod shape and displaces back and forth in the axial direction to transmit the steering force and steering amount for each of the two wheels 112 to the knuckle arms 111, and is made of a metal material. In this case, a rack gear 103a is formed on a part of the rack bar 103, and is meshed with a pinion gear 102a of the steering shaft 102. In other words, the pinion gear 102a and the rack gear 103a form a rack and pinion mechanism (steering gear box) that converts the rotational motion of the steering shaft 102 into the reciprocating linear motion of the rack bar 103.

[0032] Both axial ends of the rack bar 103 are exposed from the rack housing 104 with the rack and pinion mechanism covered by the rack housing 104. Wheels 112 are connected to both ends of the rack bar 103 exposed from the rack housing 104 via linear dampers 120, intermediate connectors 105 and knuckle arms 111, respectively.

[0033] The rack housing 104 is a component for covering and protecting the main parts such as the rack and pinion mechanism of the rack bar 103, and is made by forming a metal material into a cylindrical shape. This rack housing 104 is fixedly attached to the chassis (not shown) of the self-propelled vehicle.

[0034] The intermediate connector 105 is a component for transmitting the steering force and steering amount transmitted from the rack bar 103 to the knuckle arm 111, and is mainly composed of a rack end 106 and a tie rod 110. The rack end 106 is a component that movably connects the tie rod 110 to the tip end of the rack bar 103 and to which the linear damper 120 is connected, and is mainly composed of a stud body 107 and a socket body 108.

[0035] The stud body 107 is a component for movably connecting the tie rod 110 to the socket body 108, and is configured by forming a metal material into a round bar shape. This stud body 107 has a spherical ball portion 107a formed at one end (the left side in the figure) and a male thread portion (not shown) that screws into the end of the tie rod 110 formed at the other end (the right side in the figure).

[0036] The socket body 108 is a component for movably connecting the stud body 107 to the tip end of the relative displacement body 140, and is configured by forming a metal material into a round bar shape. More specifically, the socket body 108 is mainly configured of a socket main body 108a and a connecting portion 108b. The socket main body 108a is a portion that holds the ball portion 107a in a slidable state, and is formed in a concave spherical shape that covers the ball portion 107a. The connecting portion 108b is a shaft-shaped portion that is connected to the relative displacement body 140, and is formed with a male screw that is screwed into the relative displacement body 140.

[0037] The tie rod 110 is a part that movably connects the knuckle arm 111 to the tip of the rack end 106, and is configured by movably attaching a ball joint to the tip of a rod-shaped tie rod body. The knuckle arm 111 is a metal part that holds the wheels 112 relative to the tie rod 110 and transmits the steering force and steering amount transmitted from the tie rod 110 to the wheels 112, and is formed in a shape in which multiple rod-shaped bodies extend from the periphery of a cylindrical part. The wheels 112 are a pair of left and right parts that roll on the road surface to move the self-propelled vehicle forward or backward, and are configured by attaching rubber tires to the outside of metal wheels.

[0038] The linear dampers 120 are devices for absorbing the inertial force from the steering shaft 102 side and / or the strong pressing force (shock) transmitted from the wheels 112, and are provided between each of the left and right intermediate connectors 105 and both ends of the rack bar 103. The linear dampers 120 include an inner chamber forming body 121.

[0039] The inner chamber forming body 121 is a component that supports the relative displacement body 140 while forming the first inner chamber 125a and the second inner chamber 125b, and is configured by forming a metal material into a cylindrical shape. Axial direction A valve support portion 123 is formed in the center of the first flow control valve 127, the second flow control valve 128, and the relative displacement body 140. The valve support portion 123 is a portion that supports the first flow control valve 127, the second flow control valve 128, and the relative displacement body 140, and is formed to protrude radially inward from the inner circumferential surface 122 in an annular shape.

[0040] The valve support portion 123 has four through holes spaced equally along the circumferential direction. Axial direction A first flow control valve 127 is fitted and held in three of these four through holes, and a second flow control valve 128 is fitted and held in the remaining one through hole. A relative displacement body 140 is slidably fitted into the inner circumferential surface of the valve support part 123 with a seal ring 124 made of an elastic body fitted in. As a result, a first inner chamber 125a and a second inner chamber 125b are formed on both sides of the inner chamber forming body 121 in the axial direction of the valve support part 123.

[0041] The first inner chamber 125a and the second inner chamber 125b are portions that liquid-tightly accommodate the fluid 126, and are formed in the shape of an annular cylinder extending in the axial direction on the outer periphery of the relative displacement body 140. That is, the first inner chamber 125a and the second inner chamber 125b are formed as spatial regions between the relative displacement body 140 and the inner chamber forming body 121. In this case, the first inner chamber 125a is formed between the first inner chamber forming wall 142 of the relative displacement body 140 and the valve support portion 123.

[0042] Further, the second inner chamber 125b is formed between the second inner chamber forming wall 145 of the relative displacement body 140 and the valve support portion 123. The volumes of the first inner chamber 125a and the second inner chamber 125b change depending on the position of the relative displacement body 140 which slides back and forth within the inner chamber forming body 121. The first inner chamber 125a and the second inner chamber 125b correspond to the inner chamber according to the present invention.

[0043] The fluid 126 is a substance for causing the direct-acting damper 120 to function as a damper by the resistance when flowing through each of the three first flow control valves 127 arranged between the first inner chamber 125a and the second inner chamber 125b, and is filled in the space formed by the first inner chamber 125a and the second inner chamber 125b. The fluid 126 is made of a liquid, gel, or semi-solid substance having a flowability with a viscosity according to the specifications of the direct-acting damper 120. In this case, the viscosity of the fluid 126 is appropriately selected according to the specifications of the direct-acting damper 120. In this embodiment, the fluid 126 is made of oil, for example, mineral oil or silicone oil. The fluid 126 is a liquid, gel, or semi-solid substance having a flowability with a viscosity ... Figure 6 In the figure, this is shown by hatching within a dashed circle.

[0044] The three first flow control valves 127 are each configured as a valve that can allow bidirectional flow while restricting the flow of the fluid 126 between the first inner chamber 125a and the second inner chamber 125b. In this case, restricting the flow of the fluid 126 in the first flow control valve 127 means that the fluid 126 does not easily flow under the same conditions (e.g., pressure, viscosity of the working fluid, etc.) as the fluid 126 flows easily in the flow direction in the second flow control valve 128.

[0045] The second flow control valve 128 is configured as a valve that allows the fluid 126 to flow from the second inner chamber 125b side to the first inner chamber 125a side, and prevents the fluid 126 from flowing from the first inner chamber 125a side to the second inner chamber 125b side.

[0046] An abutment portion 131 is provided via a support base 130 at one end (left side in the figure) of both ends of this inner chamber forming body 121. The support base 130 is a component for supporting the abutment portion 131, and is configured by forming a metal material into a circular ring shape. This support base 130 has a male thread formed on the outer periphery of the end on the inner chamber forming body 121 side for threadably fitting to the end of the inner circumferential surface 122 of the inner chamber forming body 121, and a fitting portion 130a is formed on the end face of the end opposite to this end. The fitting portion 130a is a portion into which the abutment portion 131 fits, and is configured by forming a concave groove in a circular ring shape.

[0047] The abutment portion 131 is a component for mitigating the impact when the linear damper 120 collides with the rack housing 104, and is configured by forming an elastically deformable elastic body into a circular ring shape. In this embodiment, the abutment portion 131 is configured of a rubber material. This abutment portion 131 is formed with a through hole 131a penetrating in the axial direction. The through hole 131a is a hole through which a bolt 132 for attaching the abutment portion 131 to the support base 130 passes, and three through holes 131a are formed at equal intervals along the circumferential direction of the abutment portion 131.

[0048] Furthermore, a fitting portion 131b is formed at one end (the right side in the drawing) in the axial direction of the abutting portion 131, and a bottomed hole 131c is formed at the other end (the left side in the drawing). The fitting portion 131b is a portion for fitting into a concave fitting portion 130a of the support base 130 to determine the mounting position of the abutting portion 131, and a convex portion that fits into the fitting portion 130a is formed in an annular shape.

[0049] The bottomed holes 131c are holes with a bottom for adjusting the elastic force of the abutting portion 131, and three are formed between the three through holes 131a along the circumferential direction of the abutting portion 131. These bottomed holes 131c are formed to a depth of about half the axial length of the abutting portion 131. Note that the three through holes 131a also function to adjust the elastic force of the abutting portion 131, similar to the bottomed holes 131c.

[0050] The relative displacement body 140 is a part for connecting the rack bar 103 and the rack end 106 to each other and for forming the first inner chamber 125a and the second inner chamber 125b together with the inner chamber forming body 121, and is configured by forming a metal material into a round bar shape. This relative displacement body 140 is mainly configured to include an inner chamber facing portion 141, a first inner chamber forming wall 142, a second inner chamber forming wall 145, a rack end connecting portion 148, a rack bar connecting portion 149, and a compensation device accommodating portion 150.

[0051] The inner chamber facing portion 141 is a portion that forms the first inner chamber 125a and the second inner chamber 125b, respectively, and is a portion on which the valve support portion 123 slides, and is configured with a smooth curved surface that has a circular cross section. The inner chamber facing portion 141 is formed in the center of the relative displacement body 140 in the axial direction.

[0052] The first inner chamber forming wall 142 is a part that forms the first inner chamber 125a and slides on the inner circumferential surface 122 of the inner chamber forming body 121 to press the fluid 126, and is formed in a flange-like projection at one end (the right side in the figure) of the inner chamber facing part 141. In this case, the first inner chamber forming wall 142 is integrally formed of the same material as the relative displacement body 140. The inner circumferential surface 122 of the inner chamber forming body 121 is slidably fitted to the outer periphery of this first inner chamber forming wall 142 with a seal ring 143 made of an elastic body fitted therein. In addition, a first displacement limit regulating part 144 is provided on the end face of the first inner chamber 125a side of the first inner chamber forming wall 142.

[0053] The first displacement limit defining portion 144 is a component for defining one of the displacement limits at both ends of the displacement range of the relative displacement body 140 by the first inner chamber forming wall 142 displacing toward the valve support portion 123 and hitting against it, and for mitigating the impact at the time of hitting, and is configured by forming an elastically deformable elastic body into a circular ring shape. In this embodiment, the first displacement limit defining portion 144 is configured from a rubber material. Also, the first displacement limit defining portion 144 is formed into a tapered cone shape with an outer diameter larger on the first inner chamber forming wall 142 side than on the valve support portion 123 side.

[0054] The second inner-chamber forming wall 145 is a part that forms the second inner chamber 125b and slides on the inner circumferential surface 122 of the inner-chamber forming body 121 to press the fluid 126, and is provided in a flange-like protruding manner at the other end (the left side in the figure) of the inner-chamber facing part 141. This second inner-chamber forming wall 145 is configured by forming a metal material separate from the relative displacement body 140 into an annular shape, and is integrated with the relative displacement body 140 by being screwed onto the outer circumferential part of the relative displacement body 140.

[0055] In addition, the inner peripheral surface 122 of the inner chamber forming body 121 is slidably fitted onto the outer peripheral portion of the second inner chamber forming wall 145 with a seal ring 146 made of an elastic body fitted therein. Furthermore, the second inner chamber forming wall 145 is provided with a second displacement limit defining portion 147 on the end face on the second inner chamber 125b side.

[0056] The second displacement limit defining portion 147 is a component for defining the other displacement limit at both ends of the displacement range of the relative displacement body 140 when the second inner chamber forming wall 145 displaces toward the valve support portion 123 and hits against it, and for mitigating the impact when the second displacement limit defining portion 147 hits against it, and is configured by forming an elastically deformable elastic body into a circular ring shape. In this embodiment, the second displacement limit defining portion 147 is configured from a rubber material.

[0057] The rack end connecting portion 148 is a portion that connects the socket body 108 of the rack end 106, and is formed in a bottomed hole that extends in the axial direction of the relative displacement body 140 and opens to the end on the right side in the figure. In this case, the rack end connecting portion 148 has a female thread formed on the inner circumferential surface of the bottomed hole into which the male thread of the connecting portion 108b of the socket body 108 is screwed.

[0058] The rack bar connecting portion 149 is a portion that connects the rack bar 103, and is configured by forming a female thread on the inner circumferential surface of a bottomed hole that extends in the axial direction of the relative displacement body 140 and opens at the end on the left side in the figure, into which a male thread formed at the end of the rack bar 103 is screwed into. The rack end connecting portion 148 and the rack bar connecting portion 149 correspond to the mounting portion according to the present invention.

[0059] The compensation device accommodating portion 150 is a portion for liquid-tightly accommodating the volume change compensation device 153, and is formed as a bottomed hole integrally with the rack end connecting portion 148. This compensation device accommodating portion 150 communicates with the second inner chamber 125b via an inner chamber communication passage 151, and also communicates with the atmosphere outside the linear damper 120 via an atmosphere communication passage 152.

[0060] The volume change compensation device 153 is a device that compensates for volume change caused by expansion or contraction due to temperature change of the fluid 126 in the first inner chamber 125a and the second inner chamber 125b. This volume change compensation device 153 is configured by accommodating a piston that slides back and forth in the compensation device accommodating portion 150 in a state where it is elastically pressed toward the inner chamber communication passage 151 by a coil spring. In this case, the space that accommodates the coil spring communicates with the atmosphere outside the linear damper 120 via the atmosphere communication passage 152.

[0061] An elastic body holder 154 is attached to the outer cylindrical portion of the relative displacement body 140 where the rack end connecting portion 148 is formed. The elastic body holder 154 is a component for holding the return elastic body 155, and is configured by forming a metallic material into a cylindrical shape. The elastic body holder 154 holds the return elastic body 155 on its outer periphery. In this case, one end of the elastic body holder 154 in the axial direction protrudes like a flange to form a receiving portion 154a on the outer periphery, and this receiving portion 154a receives one end of the return elastic body 155.

[0062] The return elastic body 155 is a component for elastically pressing the first inner chamber forming wall 142 and the second inner chamber forming wall 145 of the relative displacement body 140 against the illustrated right end portions in the first inner chamber 125a and the second inner chamber 125b, respectively, and is configured by arranging a plurality of metal wave washers in a pile in the axial direction of the elastic body holder 154. One end portion (the right side in the figure) of this return elastic body 155 elastically presses the receiving portion 154a of the elastic body holder 154, and the other end portion (the left side in the figure) elastically presses the illustrated right end portion of the inner chamber forming body 121.

[0063] (Operation of the steering device 100) Next, the operation of the steering device 100 configured as above will be described. The steering device 100 is incorporated inside a four-wheeled self-propelled vehicle (not shown) as a mechanism for steering the steered wheels (for example, two front wheels) of the self-propelled vehicle in the left-right direction. The steering device 100 changes the directions of the two wheels 112 in response to the operation of the steering wheel 101 by the driver of the self-propelled vehicle, thereby determining the traveling direction of the self-propelled vehicle.

[0064] When such a self-propelled vehicle is being driven, the linear damper 120 in the steering device 100 acts when the rack bar 103 is displaced close to its left / right displacement limit in relation to the pinion gear 102a. In this case, the displacement limit of the rack bar 103 is the left / right steering limit of the wheels 112, and this occurs when the driver of the self-propelled vehicle turns the steering wheel 101 clockwise or counterclockwise close to its rotation limit, or when the wheels 112 collide with an obstacle such as a curb and a large input is applied to the rack bar 103 from the wheel 112 side.

[0065] First, a case will be described where the linear damper 120 does not operate because no external force acts on it. As shown in Fig. 4, in a range where the rack bar 103 does not reach the vicinity of the displacement limit, such as when the wheels 112 of the self-propelled vehicle are not steered to the vicinity of the steering limit, the linear damper 120 does not operate because the inner chamber forming body 121 does not collide with the rack housing 104. In this case, as shown in Fig. 4, the inner chamber forming body 121 of the linear damper 120 is elastically pressed to the left side in the displacement range of the inner chamber forming body 121 by the return elastic body 155, so that the second inner chamber forming wall 145 that defines the displacement limit is elastically pressed against the valve support portion 123 via the second displacement limit defining portion 147.

[0066] Next, a case where an external force acts on the linear damper 120 and the linear damper 120 operates will be described. As shown in Fig. 5, when the rack bar 103 reaches near its displacement limit, such as when the wheels 112 of the self-propelled vehicle are steered to near the steering limit, the end of the inner chamber forming body 121 comes into contact with the rack housing 104 and starts operating. That is, the rack housing 104 corresponds to the other of the two mounting objects according to the present invention. The intermediate connector 105 corresponds to one of the two mounting objects according to the present invention.

[0067] In this case, first, the linear damper 120 attenuates the impact when the abutting portion 131 abuts against the rack housing 104 and undergoes elastic deformation due to compression. Next, as shown in Fig. 6, when the abutting portion 131 of the linear damper 120 reaches the limit of elastic deformation, the relative displacement body 140 displaces within the inner chamber forming body 121 toward the rack housing 104 against the elastic force of the return elastic body 155. That is, the relative displacement body 140 is displaced while the first inner chamber forming wall 142 pushes the fluid 126 toward the valve support portion 123.

[0068] As a result, the direct-acting damper 120 generates a damping force by causing the fluid 126 in the first inner chamber 125a to flow toward the second inner chamber 125b while causing flow resistance through each of the three first flow control valves 127. When the first inner chamber forming wall 142 of the direct-acting damper 120 abuts against the valve support portion 123, the first displacement limit defining portion 144 abuts against the valve support portion 123 and attenuates the impact at the time of abutment and the external force that displaces the relative displacement body 140 by elastic deformation due to compression.

[0069] Next, when the wheels 112 of the self-propelled vehicle are steered close to the steering limit and the rack bar 103 reaches close to the displacement limit, and then the wheels 112 return to their original position, the linear damper 120 displaces the relative displacement body 140 in a direction in which the relative displacement body 140 moves away from the rack housing 104 within the inner chamber forming body 121. That is, the relative displacement body 140 is displaced by the return elastic body 155 while the second inner chamber forming wall 145 pushes the fluid 126 toward the valve support portion 123.

[0070] As a result, in the direct-acting damper 120, the fluid 126 in the second inner chamber 125b flows toward the first inner chamber 125a through one second flow control valve 128 with extremely small flow resistance. That is, the direct-acting damper 120 generates almost no damping force against the external force when the relative displacement body 140 returns to its original position. When the second inner chamber forming wall 145 of the direct-acting damper 120 abuts against the valve support portion 123, the second displacement limit defining portion 147 abuts against the valve support portion 123 and attenuates the impact at the time of the abutment by elastic deformation due to compression (see FIG. 4).

[0071] Next, after the second displacement limit defining portion 147 of the linear damper 120 abuts against the valve support portion 123, the inner chamber forming body 121 is displaced in a direction away from the rack housing 104, and the compressive deformation of the abutment portion 131 is eliminated, and the linear damper 120 is separated from the rack housing 104 (see FIG. 4). As a result, the wheels 112 of the self-propelled vehicle return to their original positions.

[0072] As can be understood from the explanation of the operating method above, according to the first embodiment, the abutment portion 131 of the linear damper 120 is configured to include an elastic body, so that even if the abutment portion 131 collides with the rack housing 104 facing the abutment portion 131 of the two rack housings 104 and intermediate connecting body 105 on which the linear damper 120 is installed and a large load is suddenly applied, the generation of a large collision sound or impact can be suppressed.

[0073] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the scope of the present invention. In the description of each modification, the same reference numerals are used to designate the same parts as those in the above-described embodiment, and redundant description will be omitted.

[0074] For example, in the above embodiment, the abutment portion 131, the first displacement limit defining portion 144, and the second displacement limit defining portion 147 are each made of a rubber material. However, it is sufficient that the abutment portion 131, the first displacement limit defining portion 144, and the second displacement limit defining portion 147 are made of an elastic body that can elastically receive an external force. In this case, the elastic body is preferably a viscoelastic body that deforms slowly in response to an external force to absorb impact or vibration. In addition, the viscoelastic body is preferably a viscoelastic body with a low resilience modulus, specifically, a viscoelastic body with a resilience modulus of 50% or less.

[0075] Therefore, the abutment portion 131, the first displacement limit defining portion 144, and the second displacement limit defining portion 147 can be made of a resin material such as a thermosetting elastomer material (e.g., vulcanized rubber, urethane rubber, silicone rubber, fluororubber, etc.) or a thermoplastic elastomer material (e.g., styrene-based, olefin-based, PVC-based, urethane-based, or amide-based resin, etc.) in addition to a rubber material. The abutment portion 131, the first displacement limit defining portion 144, and the second displacement limit defining portion 147 can also be made of a material other than an elastomer material, such as a metal leaf spring or coil spring, or a damper filled with a viscous fluid. The abutment portion 131, the first displacement limit defining portion 144, and the second displacement limit defining portion 147 can also be made by attaching a rigid resin plate or metal plate to the surface of an elastic body. As a result, the abutment portion 131, the first displacement limit defining portion 144 and the second displacement limit defining portion 147 can improve their wear resistance against an abutting object such as the rack housing 104, and can prevent damage thereto.

[0076] In the above embodiment, the abutment portion 131, the first displacement limit defining portion 144, and the second displacement limit defining portion 147 are formed in a circular ring shape. However, the abutment portion 131, the first displacement limit defining portion 144, and the second displacement limit defining portion 147 can be formed in a ring shape other than a circle (including an oval), for example, a polygonal shape such as a triangle, a rectangle, a pentagon, or a hexagon, or an irregularly shaped ring. In this case, the abutment portion 131 and the second displacement limit defining portion 147 can also be formed in a cone shape like the first displacement limit defining portion 144. The abutment portion 131, the first displacement limit defining portion 144, and the second displacement limit defining portion 147 can also be configured by arranging small pieces in a ring shape.

[0077] In the above embodiment, the abutting portion 131 is configured to include the through holes 131a and the bottomed holes 131c. This allows the elasticity of the abutting portion 131 to be adjusted. Therefore, the number, positions, or sizes of the through holes 131a and the bottomed holes 131c can be freely set in the abutting portion 131 according to the required elasticity. However, the elasticity of the abutting portion 131 can be adjusted by configuring the abutting portion 131 to include at least one of the bottomed holes and the through holes. In addition, when the abutting portion 131 has the required elasticity without using the through holes 131a and the bottomed holes 131c, the through holes 131a and the bottomed holes 131c can be omitted.

[0078] In the above embodiment, the abutment portion 131 is attached to the support base 130 by passing the bolt 132 through the through hole 131a. However, the abutment portion 131 can be attached to the support base 130 using a method other than the bolt 132, such as an adhesive or welding.

[0079] In the above embodiment, the abutment portion 131 is attached to the support base 130 via the fitting portion 131b. This allows the abutment portion 131 to be attached to the support base 130 at an accurate position and prevents the abutment portion 131 from being displaced or damaged after attachment. However, the abutment portion 131 can be configured without the fitting portion 131b. In this case, the support base 130 does not need the fitting portion 130a.

[0080] In the above embodiment, the linear damper 120 is configured to include the first displacement limit defining portion 144 and the second displacement limit defining portion 147. This allows the linear damper 120 to attenuate the impact or external force when the relative displacement body 140 receives an external force and reaches a displacement limit position, and when the relative displacement body 140 reaches a displacement limit position of its original position before receiving the external force. That is, the first displacement limit defining portion 144 and the second displacement limit defining portion 147 each correspond to the displacement limit defining portion according to the present invention. However, the linear damper 120 may be configured by omitting at least one of the first displacement limit defining portion 144 and the second displacement limit defining portion 147.

[0081] In the above embodiment, the linear damper 120 is configured to include the volume change compensation device 153. However, the linear damper 120 can be configured without the volume change compensation device 153 if the volume change of the fluid 126 can be ignored. Also, the linear damper 120 can be configured such that the volume change compensation device 153 is provided on the outside of the relative displacement body 140 or the inner chamber forming body 121.

[0082] In the above embodiment, the linear damper 120 is configured so that the relative displacement body 140 is connected to the rack bar 103 and the intermediate connector 105, respectively, and the inner chamber forming body 121 comes into contact with or moves away from the rack housing 104. However, the linear damper 120 can also be configured so that the inner chamber forming body 121 is connected to the rack housing 104, and the rack bar 103 or the intermediate connector 105 approaches or moves away from the relative displacement body 140. In this case, the relative displacement body 140 is formed in a cylindrical shape so that the rack bar 103 passes through it, and abutment portion 131 is provided at a portion where the rack bar 103 or a part of the intermediate connector 105 directly connected to the rack bar 103 approaches and makes contact due to the reciprocating displacement of the rack bar 103.

[0083] In the above embodiment, the direct-acting damper 120 is configured to include four flow control valves, namely, three first flow control valves 127 and one second flow control valve 128. However, it goes without saying that the number and specifications of the flow control valves are appropriately set according to the specifications of the direct-acting damper 120. Also, the flow control valve can be provided in the relative displacement body 140 instead of or in addition to the inner chamber forming body 121.

[0084] In the above embodiment, the linear damper 120 is configured to include the return elastic body 155 made of a wave washer. However, the return elastic body 155 can be configured of an elastic body other than a wave washer, for example, a coil spring. In addition, when the linear damper 120 does not need to be constantly pressed against the relative displacement body 140, the return elastic body 155 can be omitted.

[0085] In addition, in each of the above embodiments, the linear damper 120 is applied to the steering device 100. However, the linear damper 120 can be attached to a device or instrument other than the steering device 100, specifically, a door opening / closing mechanism, a mechanical device other than a self-propelled vehicle, an electrical device, an instrument, or furniture. [Explanation of symbols]

[0086] 100... steering device, 101... steering wheel, 102... steering shaft, 102a... pinion gear, 103... rack bar, 103a... rack gear, 104... rack housing, 105... intermediate connector, 106... rack end, 107... stud body, 107a... ball portion, 108... socket body, 108a... socket main body, 108b... connector, 110...tie rod, 111...knuckle arm, 112...wheel, 120... linear damper, 121... inner chamber forming body, 122... inner peripheral surface, 123... valve support portion, 124... seal ring, 125a... first inner chamber, 125b... second inner chamber, 126... fluid, 127... first flow control valve, 128... second flow control valve, 130...support base, 130a...fitting portion, 131...butting portion, 131a...through hole, 131b...fitting portion, 131c...bottom hole, 132...bolt, 140... relative displacement body, 141... inner chamber facing portion, 142... first inner chamber forming wall, 143... seal ring, 144... first displacement limit determining portion, 145... second inner chamber forming wall, 146... seal ring, 147... second displacement limit determining portion, 148... rack end connecting portion, 149... rack bar connecting portion, 150: compensation device accommodating portion; 151: inner chamber communicating passage; 152: atmosphere communicating passage; 153: volume change compensation device; 154: elastic body holder; 154a: receiving portion; 155: return elastic body.

Claims

1. an inner chamber forming body that is formed in a cylindrical shape and has an inner chamber that contains a fluid in a liquid-tight manner inside the cylindrical portion; a relative displacement body that is slidably fitted into the inner chamber forming body and displaced relative to the inner chamber forming body; a flow control valve provided in at least one of the inner chamber forming body and the relative displacement body, for restricting the flow of the fluid while allowing the fluid to flow, the direct-acting damper being disposed between two objects which are linearly displaced relative to each other and attenuating an external force received due to the relative displacement by restricting the flow of the fluid, One of the inner chamber forming body and the relative displacement body is The device has an attachment portion that is attached to one of the two attachment objects, The other of the inner chamber forming body and the relative displacement body is The other of the two attachment objects has an abutment portion against which the other of the two attachment objects abuts, The abutting portion is The mounting member includes an elastic body that elastically receives the abutment of the other of the two mounting objects, The inner chamber forming body and the relative displacement body are each of the first and second displacement limit defining portions defines one displacement limit and the other displacement limit in the range of the relative displacement by coming into contact with each other due to the relative displacement, The displacement limit defining portion is A linear damper, characterized in that the displacement limit defining portion of at least one of the one displacement limit and the other displacement limit is configured to include an elastic body.

2. an inner chamber forming body that is formed in a cylindrical shape and has an inner chamber that contains a fluid in a liquid-tight manner inside the cylindrical portion; a relative displacement body that is slidably fitted into the inner chamber forming body and displaced relative to the inner chamber forming body; a flow control valve provided in at least one of the inner chamber forming body and the relative displacement body, for restricting the flow of the fluid while allowing the fluid to flow, the direct-acting damper being disposed between two objects which are linearly displaced relative to each other and attenuating an external force received due to the relative displacement by restricting the flow of the fluid, One of the inner chamber forming body and the relative displacement body is The device has an attachment portion that is attached to one of the two attachment objects, The other of the inner chamber forming body and the relative displacement body is The other of the two attachment objects has an abutment portion against which the other of the two attachment objects abuts, The abutting portion is The mounting member includes an elastic body that elastically receives the abutment of the other of the two mounting objects, The relative displacement body is A linear damper comprising a volume change compensation device that compensates for a volume change of the fluid in the internal chamber.

3. The linear damper according to claim 1 or 2, A linear damper characterized by 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, thereby elastically pressing the inner chamber forming body or the relative displacement body that does not have the abutment portion toward a side away from the abutment portion.

4. The linear damper according to any one of claims 1 to 3, The linear damper is characterized in that the abutment portion is formed in an annular shape.

5. The linear damper according to any one of claims 1 to 4, The abutting portion is A linear damper characterized by being made of an elastomer material.

6. The linear damper according to claim 5, The abutting portion is A linear damper comprising at least one of a blind hole and a through hole.

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

8. 8. The steering device according to claim 7, The relative displacement body is connected to the intermediate connector, The inner chamber forming body is A steering device characterized in that the rack bar is formed so as to come into contact with or move away from the rack housing due to the reciprocating motion of the rack bar.

9. 8. The steering device according to claim 7, The inner chamber forming body is connected to an end portion of the rack housing, The relative displacement body is A steering device characterized in that the rack bar or the intermediate connector penetrates the interior of the steering device, and the rack bar or the intermediate connector is formed so as to come into contact with or separate from the rack bar due to the reciprocating motion of the rack bar.

10. a steering shaft formed in a rod shape and rotated by operation of a steering wheel; a rack bar formed in a rod shape for converting a rotational motion of the steering shaft into a reciprocating motion in an axial direction and transmitting the rotational motion; An intermediate connector that is connected to both ends of the rack bar and directly or indirectly connects wheels to be steered to the both ends; A steering device comprising: a rack housing covering the rack bar, an inner chamber forming body that is formed in a cylindrical shape and has an inner chamber that contains a fluid in a liquid-tight manner inside the cylindrical portion; a relative displacement body that is slidably fitted into the inner chamber forming body and displaced relative to the inner chamber forming body; a flow control valve provided in at least one of the inner chamber forming body and the relative displacement body, for restricting the flow of the fluid while allowing the fluid to flow, the direct-acting damper being disposed between two objects which are linearly displaced relative to each other and attenuating an external force received due to the relative displacement by restricting the flow of the fluid, One of the inner chamber forming body and the relative displacement body is The device has an attachment portion that is attached to one of the two attachment objects, The other of the inner chamber forming body and the relative displacement body is The other of the two attachment objects has an abutment portion against which the other of the two attachment objects abuts, The abutting portion is a linear damper including an elastic body that elastically receives the impact of the other of the two mounting objects, The linear damper is a shock absorber provided between the rack housing and the rack bar or the intermediate connecting body to attenuate an impact from the wheels and / or an impact due to an inertial force from the steering shaft side; The inner chamber forming body is connected to an end portion of the rack housing, The relative displacement body is A steering device characterized in that the rack bar or the intermediate connector penetrates the interior of the steering device, and the rack bar or the intermediate connector is formed so as to come into contact with or separate from the rack bar due to the reciprocating motion of the rack bar.

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