Suspension device

Abstract

The present disclosure relates to a suspension device including: a lower arm connected to a wheel carrier and configured to be rotatable up and down according to a movement of the wheel carrier; a frame portion connected to the lower arm and configured to receive movement of the wheel carrier; and a restraining portion provided on the frame portion and configured to restrain a rotation range of the lower arm. The suspension device according to the present disclosure may secure a distance and a space between parts disposed inside the suspension device by deleting a damper.

Description

Technical Field

[0001] Exemplary embodiments of this disclosure relate to a suspension device, and more specifically, to a suspension device configured to improve ride comfort by absorbing vibrations or shocks generated between the axle and the road surface during vehicle operation. Background Technology

[0002] Typically, a vehicle's suspension system is a device connected to the axle to control vibrations or impacts from the road surface while the vehicle is in motion, preventing these vibrations or impacts from being directly transmitted to the vehicle body and improving ride comfort. The suspension system includes coil springs, shock absorbers that control the free movement of the coil springs, and stabilizer bars that suppress vehicle roll.

[0003] Traditional shock absorbers are installed between the vehicle body and the wheels to absorb natural vibrations caused by shocks received by coil springs during vehicle movement. Depending on the location and motion characteristics of the shock absorber mounted on the vehicle body, shock absorbers can have different structures for their connecting parts.

[0004] However, many parts such as washers and bushings are required to install shock absorbers. The rubber bushings of the shock absorber may continuously contract and expand. In this case, the rubber bushings may tear or wear due to continuous and repeated movement.

[0005] The background technology disclosed herein is disclosed in Korean Patent Application No. 10-2024-0002483 (published on March 11, 2024, entitled "Rear Shock Absorber for Vehicles"). Utility Model Content

[0006] Various embodiments of this disclosure relate to a suspension system that can reduce vehicle weight and ensure space between internal vehicle components by eliminating shock absorbers.

[0007] In embodiments of this disclosure, the suspension device includes: a lower arm connected to a wheel carrier and configured to rotate vertically in response to movement of the wheel carrier; a frame portion connected to the lower arm and configured to receive movement of the wheel carrier; and a constraint portion disposed on the frame portion and configured to constrain the rotational range of the lower arm.

[0008] The lower arm includes a first fixing hole disposed opposite to the wheel frame, and wherein the frame portion includes a second fixing hole disposed facing the first fixing hole, and the suspension device further includes a fixing member that passes through the first fixing hole and the second fixing hole and serves as the rotation center axis of the lower arm.

[0009] The frame portion includes a guide hole configured to be opposite the wheel frame to the second fixing hole, and the guide hole is configured to guide the movement of the constraint portion on the frame portion.

[0010] The constraint portion includes: a shaft portion inserted into the guide hole; and a stepped portion connected to the shaft portion and configured to protrude outward with a diameter larger than the guide hole to prevent the shaft portion from moving.

[0011] The lower arm includes a constraint hole with the same diameter as the shaft portion.

[0012] The guide hole has a curved surface that is in perpendicular contact with the shaft portion.

[0013] The guide hole has surfaces that contact the shaft portion on the left and right sides and has the same curvature as the rotation center axis of the lower arm.

[0014] The guide hole has a vertically elongated shape and constrains the range of rise or fall of the lower arm connected to the wheel frame when the wheel frame rotates up or down.

[0015] The shaft portion includes an isolation section disposed between the lower arm and the frame portion.

[0016] The isolation portion comprises a material with a lower hardness than the lower arm and the frame portion, in order to reduce friction with the lower arm at the contact surface when the lower arm rotates upward or downward.

[0017] The suspension system according to this disclosure can ensure the distance and space between the parts arranged inside the suspension system by eliminating the shock absorber.

[0018] The suspension device according to this disclosure can reduce the weight of a vehicle by eliminating the shock absorbers.

[0019] The suspension device according to this disclosure can reduce the manufacturing cost of the shock absorber by eliminating the shock absorber. Attached Figure Description

[0020] Figure 1 This is a schematic perspective view of a suspension device according to an embodiment of the present disclosure.

[0021] Figure 2 A suspension device according to an embodiment of the present disclosure is illustrated schematically.

[0022] Figure 3 The lower arm of a suspension device according to an embodiment of the present disclosure is shown schematically.

[0023] Figure 4The schematic diagram illustrates a frame portion of a suspension device according to an embodiment of the present disclosure.

[0024] Figure 5 The schematic diagram illustrates the fixing member of a suspension device according to an embodiment of the present disclosure.

[0025] Figure 6 The fixed shaft of a suspension device according to an embodiment of the present disclosure is schematically shown.

[0026] Figure 7 The connecting members of a suspension device according to an embodiment of the present disclosure are illustrated schematically.

[0027] Figure 8 The constraint portion of a suspension device according to an embodiment of the present disclosure is illustrated schematically.

[0028] Figure 9 The diagram schematically illustrates the connection between the lower arm and the restraint portion of a suspension device according to an embodiment of the present disclosure.

[0029] Figure 10 The guide hole of the suspension device according to an embodiment of the present disclosure is schematically shown.

[0030] Figure 11 The rotational state of the lower arm of the suspension device according to an embodiment of the present disclosure is schematically shown.

[0031] Figure 12A The springback state of a suspension device according to an embodiment of the present disclosure is schematically shown.

[0032] Figure 12B The raised state of the suspension device according to an embodiment of the present disclosure is schematically shown.

[0033] Figure 13 The isolation section of a suspension device according to an embodiment of the present disclosure is illustrated schematically. Detailed Implementation

[0034] In the following, embodiments of the suspension device according to the present disclosure will be described in detail with reference to the accompanying drawings through several exemplary embodiments. It should be understood that, for clarity and convenience of description, the thickness of each line or the size of each component in the drawings may be exaggerated.

[0035] In this process, for clarity and convenience, the thickness of lines or the dimensions of elements shown in the accompanying drawings may have been enlarged. The terms described below are defined by consideration of their function in this disclosure and may vary depending on the intent or practice of the user or operator. Therefore, these terms should be interpreted based on the entire contents of this specification.

[0036] Furthermore, in this specification, when a part is "connected (or linked)" to another part, it includes not only "directly connected (or linked) to" the other part, but also "indirectly connected (or linked) to" the other part (through another component between them). In this specification, when a part "includes (or has) a component," this means that it also "includes (or has)" other components, rather than excluding other components, unless explicitly stated otherwise.

[0037] The purpose and effects of this disclosure may be naturally understood or become clearer from the following description, and the purpose and effects of this disclosure are not limited to the following description. Furthermore, in describing this disclosure, detailed descriptions of known techniques related to this disclosure will be omitted if it is determined that such descriptions might unnecessarily obscure the main points of this disclosure.

[0038] Figure 1 This is a schematic perspective view of a suspension device 1 according to an embodiment of the present disclosure. Figure 2 The suspension device 1 according to an embodiment of the present disclosure is illustrated schematically. Figure 3 The lower arm 100 of the suspension device 1 according to an embodiment of the present disclosure is schematically shown.

[0039] refer to Figure 1 The suspension device 1 according to the embodiments of the present disclosure includes a lower arm 100, a frame portion 200 and a restraint portion 300.

[0040] The lower arm 100 is connected to the wheel carrier 400 so that it can rotate up and down as the wheel carrier 400 moves.

[0041] The suspension device 1 is a device connected between the axle and the vehicle body frame and absorbs vibrations or shocks transmitted from the road surface during driving, thereby improving the ride comfort and stability of the vehicle. The suspension device 1 includes a wheel carrier 400 that rotatably supports the wheel, and a lower arm 100 and an upper arm (not shown) that are arranged along the width direction of the vehicle and connected to the wheel carrier 400 to enable the vehicle body to rotate.

[0042] According to one embodiment of the present disclosure, the suspension device 1 includes a lower arm 100 disposed on one side and an elastic member 700 supporting the vehicle body and disposed on the other side.

[0043] Reference Figure 1 The elastic member 700 supporting the vehicle body is mounted on the lower arm 100. Because the elastic member 700 supports bending caused by irregular and repeated up-and-down movements, torsion caused by centrifugal force during cornering, and the load of the vehicle, the lower arm 100 needs to be durable and rigid.

[0044] In this embodiment, the elastic member 700 is described as an example of an elastically deformable helical spring, but this disclosure is not limited thereto and various modifications can be made.

[0045] Reference Figure 2 The coil spring is configured such that one end is connected to the vehicle body and the other end is connected to the lower arm 100 to absorb impacts transmitted from the road surface.

[0046] Reference Figure 3 The lower arm 100 is provided with: an elastic member mounting portion 130 for mounting a spring; and a mounting extension 131 provided on the edge of the elastic member mounting portion 130, such that the spring is mounted on the lower arm 100 without separating. The lower arm 100 can be manufactured by aluminum forging or aluminum extrusion to reduce weight.

[0047] The lower arm 100 is connected to the stabilizer bar link, so that the vehicle's motion can be transmitted to the stabilizer bar 500 when the vehicle is turning.

[0048] When the vehicle body is unbalanced, the stabilizer bar 500 is controlled to reduce the vehicle body tilt and restore the vehicle body's posture to a balanced state. The stabilizer bar 500 is positioned across the left and right sides of the vehicle, and both ends of the stabilizer bar 500 are connected to stabilizer bar links (not shown), and the stabilizer bar links are rotatably connected to the lower arm 100. Therefore, the movement of the lower arm 100 can be transmitted to the stabilizer bar 500 and the frame portion 200.

[0049] In the accompanying drawings, the X-axis direction represents a direction parallel to the longitudinal direction of the lower arm 100, and the Y-axis direction represents a direction perpendicular to the longitudinal direction of the lower arm 100 and parallel to the longitudinal direction of the constraint portion 300. The X-axis and Y-axis directions can be mutually perpendicular. The Z-axis direction represents a direction perpendicular to both the longitudinal direction of the lower arm 100 and the longitudinal direction of the constraint portion 300. In other words, the Z-axis direction can be a direction perpendicular to the XY plane.

[0050] Furthermore, in the accompanying drawings, the first horizontal direction, the second horizontal direction, and the vertical direction can be understood as follows: the first horizontal direction can be understood as the X-axis direction, the second horizontal direction can be understood as the Y-axis direction, and the vertical direction can be understood as the Z-axis direction.

[0051] Reference Figure 2 and Figure 3 The lower arm 100 includes a first fixing hole 110, which is located on the side opposite to the wheel carrier 400 and is rotatable according to the movement of the wheel carrier 400. A fixing member 600, described later, passes through the first fixing hole 110, such that the lower arm 100 can rotate in the vertical direction (Z-axis direction) about the fixing member 600 as the axis of rotation.

[0052] The lower arm 100 is provided with a constraint hole 120, which has the same diameter as the shaft portion 310 described below. Because the constraint hole 120 of the lower arm 100 has the same diameter as the shaft portion 310, the movement of the lower arm 100 in the vertical direction (Z-axis direction) can be transmitted to the constraint portion 300.

[0053] Figure 4 The frame portion 200 of a suspension device according to an embodiment of the present disclosure is shown schematically.

[0054] refer to Figure 2 and Figure 4 The frame portion 200 is rotatably connected to the lower arm 100, so that the movement of the wheel carrier 400 is transmitted.

[0055] The frame portion 200 is connected to the lower arm 100, so that the motion of the wheel carrier 400 is transmitted.

[0056] The frame portion 200 includes a second fixing hole 210 configured to face the first fixing hole 110. The second fixing hole 210 is configured as an ellipse along a longer length of a first horizontal direction (X-axis direction). (See reference...) Figure 4 A second fixing hole 210 is provided on both sides of the frame part 200.

[0057] The second fixing hole 210 and the first fixing hole 110 are arranged on the same straight line. The fixing member 600 passes through the first fixing hole 110 and the second fixing hole 210, so that the lower arm 100 can rotate up and down about the fixing member 600 as the axis of rotation. The frame portion 200 includes a guide hole 220 provided on the side opposite to the wheel frame 400 relative to the second fixing hole 210, to guide the movement of the restraint portion 300 on the frame portion 200. The guide hole 220 is spaced apart from the second fixing hole 210.

[0058] The guide hole 220 has a vertical length. The constraint portion 300 is fitted into the guide hole 220 and rotates vertically (i.e., in the vertical direction (Z-axis direction)). Specifically, the guide hole 220 can constrain the movement of the shaft portion 310 described below.

[0059] Figure 5 The fixing member 600 of the suspension device according to an embodiment of the present disclosure is illustrated schematically.

[0060] refer to Figure 5 The fixing member 600 passes through the first fixing hole 110 and the second fixing hole 210 and becomes the rotation center axis of the lower arm 100. In this case, the first fixing hole 110, the second fixing hole 210, and the fixing member 600 are arranged on the same line and have the same rotation center axis. Therefore, the lower arm 100 can rotate about the fixing member 600.

[0061] The fixing member 600 includes a fixing shaft 610 and a connecting member 620.

[0062] Figure 6 The fixed shaft 610 of the suspension device according to an embodiment of the present disclosure is schematically shown.

[0063] refer to Figure 6 The fixed shaft 610 refers to the shaft that passes through the first fixing hole 110 and the second fixing hole 210. In this embodiment, the fixed shaft 610 is described as a cylindrical shaft as an example, but this disclosure is not limited thereto, and various modifications are possible.

[0064] The fixed shaft 610 includes an inwardly recessed fixing groove 611. The suspension device 1 according to an embodiment of the present disclosure also includes a cam bolt 630, such that the fixed shaft 610 is engaged without gap when it passes through the second fixing hole 210.

[0065] The cam bolt 630 can adjust the toe angle and camber angle by changing the fixed position of the lower arm 100 according to the rotation angle. By including the cam bolt 630, the lower arm 100 can rotate about the fixed member 600, which serves as the axis of rotation.

[0066] The cam bolt 630 has a protrusion of the adapter fixing groove 611 corresponding to the fixing groove 611 of the fixing shaft 610. Since the protrusion of the adapter fixing groove 611 is inserted into and connected to the fixing groove 611, the fixing shaft 610 can be prevented from spinning freely while the fixing shaft 610 is connected without gaps.

[0067] refer to Figure 5 By connecting the cam bolt 630 to the fixed shaft 610 and then connecting the fixing bolt 640 to the fixed shaft 610, the connection between the fixed shaft 610, the first fixing hole 110 and the second fixing hole 210 can be stably supported.

[0068] Figure 7 The connecting member 620 of the suspension device according to an embodiment of the present disclosure is illustrated schematically.

[0069] Reference Figure 7 The connecting member 620 is configured to surround the fixed shaft 610 to prevent the fixed shaft 610 from rotating freely. For example... Figure 7 As shown, the connecting member 620 has a hole through which the fixing shaft 610 passes. That is, the connecting member 620 surrounding the fixing shaft 610 and the fixing shaft 610 pass through the first fixing hole 110 as a unit.

[0070] Reference Figure 3 and Figure 4The dimensions of the first fixing hole 110 and the second fixing hole 210 can be different. When the diameters of the first fixing hole 110, the second fixing hole 210, and the fixing member 600 are the same, the lower arm 100 cannot rotate freely around the fixing member 600, which serves as the axis of rotation. Therefore, the dimensions of the first fixing hole 110 and the second fixing hole 210 are different. To prevent the fixing shaft 610, which passes through the first fixing hole 110 and the second fixing hole 210, from spinning freely in the first fixing hole 110, which has a larger diameter, the connecting member 620 is configured to surround the fixing shaft 610 when passing through the first fixing hole 110.

[0071] Figure 8 The constraint portion 300 of a suspension device according to an embodiment of the present disclosure is illustrated schematically.

[0072] refer to Figure 8 The constraint portion 300 includes a shaft portion 310, a step portion 320, and a guide fastening portion 330.

[0073] The shaft portion 310 is inserted into the guide hole 220. In this embodiment, the shaft portion 310 is described as a cylindrical column, but this disclosure is not limited thereto, and various modifications are possible.

[0074] The stepped portion 320 is connected to the shaft portion 310 and protrudes outward with a diameter larger than that of the guide hole 220 to prevent the shaft portion 310 from moving. The stepped portion 320 protrudes outward to prevent the shaft portion 310 from moving in the second horizontal direction (Y-axis direction).

[0075] The stepped portion 320 has a larger diameter than the shaft portion 310 or the guide hole 220. Therefore, the restraint portion 300 can be fixed and does not move in the second horizontal direction (Y-axis direction) between the lower arm 100 and the frame portion 200.

[0076] The guide fastener 330 is connected to the stepped portion 320 and restricts the movement of the shaft portion 310. Specifically, the guide fastener 330, which has internal threads, is screwed and secured to the shaft portion 310, which has external threads. The guide fastener 330 is secured to the outside of the stepped portion 320 by a nut to further constrain and secure the movement of the restraint portion 300 in the second horizontal direction (Y-axis direction).

[0077] Since the fixing member 600 passes through the first fixing hole 110 and the second fixing hole 210, the lower arm 100 rotates up and down when the fixing member 600 is inserted into the lower arm 100, and the frame portion 200 and the constraint portion 300 pass through the guide hole 220 which is spaced apart from the second fixing hole 210, thereby limiting the vertical rotation range of the lower arm 100.

[0078] The frame portion 200 opens downwards, and the lower arm 100 connects to the open space of the frame portion 200. Therefore, the lower arm 100 rotates while overlapping with the frame portion 200, thereby increasing space utilization.

[0079] Figure 9 The diagram schematically illustrates the connection between the lower arm 100 and the restraint portion 300 of a suspension device according to an embodiment of the present disclosure.

[0080] refer to Figure 9 The constraint portion 300 is fitted into a constraint hole 120 having the same diameter as the shaft portion 310 so that they are not spaced apart from each other, and thus the lower arm 100 can be fixed and cannot move in the first horizontal direction "a" (X-axis direction), where the first horizontal direction "a" is the horizontal direction of the lower arm 100. Therefore, the rotation direction of the lower arm 100 is in the vertical direction (Z-axis direction) rather than in the first horizontal direction (a, X-axis direction).

[0081] Figure 10 The guide hole 220 of the suspension device according to an embodiment of the present disclosure is schematically shown.

[0082] Reference Figure 10 The surface of the guide hole 220 that is in perpendicular contact with the shaft portion 310 is formed as a curved surface. Hereinafter, the surface of the guide hole 220 that is in perpendicular contact with the shaft portion 310 is referred to as the first surface 221. The first surface 221 in which the guide hole 220 and the shaft portion 310 are in perpendicular contact is formed as a curved surface by molding.

[0083] Since the first surface 221 is set as a curved surface, the constraint portion 300 will not be damaged when the constraint portion 300 reciprocates in the vertical direction (Z-axis direction).

[0084] The guide hole 220 has a curvature on its left and right surfaces that contact the shaft portion 310, based on the same rotation center axis of the lower arm 100. Hereinafter, the surfaces of the guide hole 220 that contact the shaft portion 310 on the left and right sides are referred to as the second surface 222. The second surface 222 is formed as a curved surface along the path c of the rotating lower arm 100.

[0085] refer to Figure 10 Because the lower arm 100 rotates vertically (in the Z-axis direction) relative to the fixing member 600 passing through the second fixing hole 210, the lower arm 100 reciprocates in a curved manner in the guide hole 220 spaced apart from the second fixing hole 210. Since the second surface 222 is formed as a curved surface, the rotating lower arm 100 can reciprocate more easily.

[0086] Figure 11The rotational state of the lower arm 100 of the suspension device according to an embodiment of the present disclosure is schematically shown.

[0087] Reference Figure 11 The distance d from the first fixing hole 110 to the wheel frame 400 is longer than the distance d' from the first fixing hole 110 to the constraint hole 120. Therefore, the vertical movement of the wheel frame 400 can be easily transferred from the constraint hole 120 to the movement of the constraint part 300.

[0088] Furthermore, when the wheel frame 400 rotates clockwise, the constraint part 300 rotates counterclockwise (i.e., downwards) because the constraint hole 120 also rotates clockwise.

[0089] like Figure 11 As shown, when the wheel frame 400 rotates counterclockwise, the constraint hole 120 also rotates counterclockwise, so the constraint member 300 rotates clockwise (i.e., upward). Therefore, the constraint part 300 can limit the rotation radius of the lower arm 100.

[0090] When a vehicle is traveling on a bumpy road, the body vibrates and the wheels also vibrate up and down. In this situation, when the wheels are rising, it is called the bump state, and when the wheels are falling, it is called the rebound state.

[0091] Figure 12A The springback state of a suspension device according to an embodiment of the present disclosure is schematically shown.

[0092] Reference Figure 12A When the wheel descends (counterclockwise) and the wheel carrier 400 rotates downward, the position of the constraint hole 120 on the side of the lower arm 100 opposite to the wheel carrier 400 rises. When the wheel carrier 400 rotates downward, the guide hole 220 can constrain the range of rise of the lower arm 100 connected to the wheel carrier 400.

[0093] Figure 12B The raised state of the suspension device according to an embodiment of the present disclosure is schematically shown.

[0094] Reference Figure 12B As the wheel rises (clockwise) and the wheel carrier 400 rotates upward, the position of the constraint hole 120 on the side of the lower arm 100 opposite to the wheel carrier 400 descends. The guide hole 220 is configured in a vertically elongated shape and can constrain the range of descent of the lower arm 100 connected to the wheel carrier 400 when the wheel carrier 400 rotates upward.

[0095] Therefore, the lower arm 100 is installed between the wheel carrier 400 and the vehicle body and limits the range of raising or lowering of the lower arm 100, thereby reducing the impact on the driver and improving ride comfort and driving stability.

[0096] Figure 13 The isolation section 311 of the suspension device according to an embodiment of the present disclosure is illustrated schematically.

[0097] Reference Figure 13 The shaft portion 310 includes an isolation portion 311 located between the lower arm 100 and the frame portion 200 and preventing the shaft portion 310 from moving in the longitudinal direction. That is, the shaft portion 310 includes an isolation portion 311 to prevent the shaft portion 310 from moving in the second horizontal direction "b".

[0098] The isolation part 311 includes a material with a lower hardness than the lower arm 100 and the frame part 200, so as to reduce the friction that occurs at the contact surface with the lower arm 100 when the lower arm 100 rotates up and down.

[0099] The isolation portion 311 is configured to surround the shaft portion 310 and contact the lower arm 100. In this case, when the lower arm 100 rotates up and down, friction occurs on the contact surface, so a material with low hardness can be included to reduce friction.

[0100] Specifically, the isolation portion 311 includes an elastically deformable material. Because the isolation portion 311 includes an elastically deformable material, the lower arm 100 is fixed so as not to move in the second horizontal direction "b" (Y-axis direction), and the friction generated when the lower arm 100 and the frame portion 200 come into contact with the isolation portion 311 can be minimized.

[0101] In this embodiment, the isolation portion 311 is described as an example of a rubber material, but this disclosure is not limited thereto, and various modifications are possible.

[0102] Therefore, the following effects can be obtained in the suspension device according to the embodiments of the present disclosure.

[0103] The suspension system according to this disclosure can ensure the distance and space between the parts arranged inside the suspension system by eliminating the shock absorber.

[0104] The suspension device according to this disclosure can reduce the weight of a vehicle by eliminating the shock absorbers.

[0105] The suspension device according to this disclosure can reduce the manufacturing cost of the shock absorber by eliminating the shock absorber.

[0106] The suspension device according to this disclosure can reduce vehicle height by eliminating shock absorbers and can improve ride quality.

[0107] The suspension device according to this disclosure can simplify and reduce the manufacturing process by eliminating components such as rubber bushings used in shock absorbers.

[0108] The suspension device according to this disclosure can reduce manufacturing costs by eliminating components such as rubber bushings used in shock absorbers.

[0109] The suspension device according to this disclosure can limit the amount of lift and rebound by adding a guide hole structure to the frame, which is an existing component.

[0110] Although this disclosure has been described with reference to embodiments shown in the accompanying drawings, the embodiments of this disclosure are for illustrative purposes only, and those skilled in the art will understand that various modifications and other equivalent embodiments are possible.

Claims

1. A suspension device, characterized in that, The suspension device includes: The lower arm is connected to the wheel frame and configured to rotate up and down according to the movement of the wheel frame; The frame portion, connected to the lower arm and configured to receive the movement of the wheel frame; and A constraint portion is provided on the frame portion and configured to constrain the rotation range of the lower arm.

2. The suspension device according to claim 1, characterized in that: in, The lower arm includes a first fixing hole disposed opposite to the wheel frame, and The frame portion includes a second fixing hole configured to face the first fixing hole. The suspension device further includes a fixing member that passes through the first fixing hole and the second fixing hole and serves as the rotation center axis of the lower arm.

3. The suspension device according to claim 2, characterized in that, The frame portion includes a guide hole configured to be opposite the wheel frame to the second fixing hole, and the guide hole is configured to guide the movement of the constraint portion on the frame portion.

4. The suspension device according to claim 3, characterized in that, The constraint portion includes: The shaft portion is inserted into the guide hole; and The stepped portion is connected to the shaft portion and is configured to protrude outward with a diameter larger than the guide hole to prevent the shaft portion from moving.

5. The suspension device according to claim 4, characterized in that, The lower arm includes a constraint hole with the same diameter as the shaft portion.

6. The suspension device according to claim 4, characterized in that, The guide hole has a curved surface that is in perpendicular contact with the shaft portion.

7. The suspension device according to claim 4, characterized in that, The guide hole has surfaces that contact the shaft portion on the left and right sides and has the same curvature as the rotation center axis of the lower arm.

8. The suspension device according to claim 4, characterized in that, The guide hole has a vertically elongated shape and constrains the range of rise or fall of the lower arm connected to the wheel frame when the wheel frame rotates up or down.

9. The suspension device according to claim 8, characterized in that, The shaft portion includes an isolation section disposed between the lower arm and the frame portion.

10. The suspension device according to claim 9, characterized in that, The isolation portion comprises a material with a lower hardness than the lower arm and the frame portion, in order to reduce friction with the lower arm at the contact surface when the lower arm rotates upward or downward.

Images