Suspension device

Abstract

To deform a plate spring as designed when a vehicle body and an axle relatively move in the vertical direction.SOLUTION: A suspension device comprises: a pair of left and right plate springs 11 which extends in a front-rear direction X, is attached to a vehicle body B1, and supports an axle W; and a torsion bar 12 which extends in the front-rear direction and in which an end of one of a front end part and a rear end part is supported to the axle in such a state that the movement in the front-rear direction and a left-right direction Y is regulated. The end of one of the front end part and the rear end part in the plate spring is connected to the vehicle body in a rotatable manner around a first axial line O1 extending in the left-right direction. The end of the other is connected to the vehicle body in a swingable manner in the front-rear direction around the axial line extending in the left-right direction. The end of the other of the front end part and the rear end part in the torsion bar is supported to the vehicle body in a movable manner in the front-rear direction in such a state that the movement in the left-right direction is regulated.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a suspension device.

Background Art

[0002] Conventionally, for example, as shown in Patent Document 1 below, a pair of left and right leaf springs that extend in the front-rear direction, are attached to the vehicle body, and support the axle, and a torsion bar that extends in the front-rear direction and has a rear end supported by the axle are provided. Among the leaf springs, the front end is rotatably connected to the vehicle body about an axis extending in the left-right direction, and the rear end is swingably connected to the vehicle body in the front-rear direction about an axis extending in the left-right direction. A suspension device in which the front end of the torsion bar is supported by the vehicle body via a rubber bush is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional suspension device, since the front end of the torsion bar is supported by the vehicle body via a rubber bush, when the vehicle body and the axle relatively move in the vertical direction while deforming the leaf spring in the vertical direction, the displacement in the front-rear direction at the front end of the torsion bar is suppressed, and the expansion and contraction deformation of the leaf spring in the front-rear direction is suppressed. As a result, when the vehicle body and the axle relatively move in the vertical direction, the leaf spring may not deform as designed, and the smooth relative movement of the vehicle body and the axle in the front-rear direction may be hindered, deteriorating the riding comfort.

[0005] This invention has been made in consideration of such circumstances, and an object thereof is to provide a suspension device that can deform a leaf spring as designed when a vehicle body and an axle relatively move in the vertical direction.

Means for Solving the Problem

[0006] To solve the above problems and achieve such an object, the suspension device of the present invention includes a pair of left and right leaf springs that extend in the front-rear direction, are attached to the vehicle body, and support the axle, and a torsion bar that extends in the front-rear direction and has one end of either the front end or the rear end supported by the axle in a state where movement in the front-rear direction and the left-right direction is restricted. One end of either the front end or the rear end of the leaf spring is rotatably connected to the vehicle body about an axis extending in the left-right direction, and the other end is swingably connected to the vehicle body about an axis extending in the left-right direction in the front-rear direction. The other end of either the front end or the rear end of the torsion bar is supported by the vehicle body so as to be movable in the front-rear direction in a state where movement in the left-right direction is restricted.

[0007] One end of either the front end or the rear end of the torsion bar is supported by the axle in a state where movement in the front-rear direction and the left-right direction is restricted, and the other end is supported by the vehicle body so as to be movable in the front-rear direction in a state where movement in the left-right direction is restricted. Therefore, when the vehicle body and the axle relatively move in the up-down direction while the leaf spring is elastically deformed in the up-down direction, the other end of the torsion bar can be moved in the front-rear direction with respect to the vehicle body following the expansion and contraction deformation of the leaf spring in the front-rear direction, and the leaf spring can be deformed as designed. As a result, when the vehicle body and the axle relatively move in the up-down direction, the vehicle body and the axle can be relatively moved smoothly in the front-rear direction, and deterioration of the riding comfort can be prevented.

[0008] The other end of the torsion bar may be provided with a support cylinder that is slidably fitted in the front-rear direction, and the support cylinder may be swingably connected to the vehicle body about a rotational axis extending in the left-right direction in the front-rear direction.

[0009] Since the support cylinder, in which the other end of the torsion bar is fitted so as to be slidable in the front-rear direction, is connected to the vehicle body so as to be swingable in the front-rear direction about a rotation axis extending in the left-right direction, when the vehicle body and the axle move relative to each other in the vertical direction, while swinging the support cylinder in the front-rear direction about the rotation axis, it becomes possible to slide the other end of the torsion bar in the front-rear direction with respect to the support cylinder. Thus, the frictional force generated between the support cylinder and the other end of the torsion bar is suppressed, and the vehicle body and the axle can be relatively moved more smoothly in the front-rear direction.

[0010] The cross-sectional shape of the outer peripheral surface of the torsion bar may be angular, or oval-shaped that is long in the left-right direction, or elliptical.

[0011] Since the cross-sectional shape of the outer peripheral surface of the torsion bar is angular, or oval-shaped that is long in the left-right direction, or elliptical, the torsional rigidity of the torsion bar is increased, and the roll rigidity and lateral rigidity between the vehicle body and the axle can be improved. Also, it becomes possible to easily restrict the rotational movement of the torsion bar along the central axis of the support cylinder, and the roll rigidity can be surely improved.

Advantages of the Invention

[0012] According to this invention, when the vehicle body and the axle move relative to each other in the vertical direction, the leaf spring can be deformed as designed.

Brief Description of the Drawings

[0013]

Figure 1

Embodiments for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the suspension device will be described with reference to FIG. 1. The suspension device 1 includes a leaf spring 11 and a torsion bar 12. In a state where the longitudinal directions of the leaf spring 11 and the torsion bar 12 respectively coincide with the longitudinal direction X of the vehicle, the leaf spring 11 supports an axle W extending in the left - right direction Y of the vehicle, and the torsion bar 12 is used to connect the axle W and the vehicle body B1 to each other in the longitudinal direction X.

[0015] Two leaf springs 11 are provided at intervals in the left - right direction Y. The central region of the leaf spring 11 in the longitudinal direction X supports the axle W, and the leaf spring 11 is provided so as to be elastically deformable in the up - down direction Z. The leaf spring 11 supports the axle W from above the axle W. Note that the leaf spring 11 may also support the axle W from below the axle W. The leaf spring 11 is formed of, for example, a fiber - reinforced resin. Examples of the fibers contained in the fiber - reinforced resin include glass fibers and carbon fibers. In the illustrated example, it is formed of a fiber - reinforced resin containing glass fibers. The fibers are contained in the resin in a state that extends substantially in the longitudinal direction X. Note that the leaf spring 11 may be formed of metal or the like.

[0016] When the leaf spring 11 is mounted on the vehicle, it extends upward and curves in a convex - downward curved surface shape from the central region toward the outer end along the longitudinal direction X. Note that when the leaf spring 11 is mounted on the vehicle, it may extend straight in the longitudinal direction X, or it may extend downward and curve in a convex - upward curved surface shape from the central region toward the outer end along the longitudinal direction X.

[0017] Of the front end and the rear end of the leaf spring 11, one end is rotatably connected to the vehicle body B1 around a first axis (axis) O1 extending in the left - right direction Y, and the other end is swingably connected to the vehicle body B1 around an axis (not shown) extending in the left - right direction Y in the longitudinal direction X. In the illustrated example, the front end portion of the leaf spring 11 is attached to the vehicle body B1 via the first ball portion 13, and the rear end portion of the leaf spring 11 is attached to the vehicle body B1 via the second ball portion 14. The first ball portion 13 and the second ball portion 14 are separate from the leaf spring 11. Note that the first ball portion 13 and the second ball portion 14 may be formed integrally with the leaf spring 11.

[0018] The first ball portion 13 is rotatably connected to the vehicle body B1 about a first axis O1 extending in the left - right direction Y. The second ball portion 14 is connected to the vehicle body B1 via a connecting piece (not shown). The connecting piece extends in the up - down direction Z. The upper end portion of the connecting piece is rotatably connected to the vehicle body B1 about an axis (not shown) extending in the left - right direction Y, and the lower end portion of the connecting piece is rotatably connected to the second ball portion 14 about a second axis O2 extending in the left - right direction Y. From the above, the second ball portion 14 is provided so as to be swingable in the front - rear direction X about the axis located above the second axis O2. Note that the second ball portion 14 may be directly connected to the vehicle body B1 rotatably about the second axis O2, and the first ball portion 13 may be connected to the vehicle body B1 via the connecting piece and provided so as to be swingable in the front - rear direction X.

[0019] Of the front end portion and the rear end portion of the torsion bar 12, one of the end portions is supported by the axle W in a state where movement in the front - rear direction X and the left - right direction Y is restricted, and the other end portion is supported by the vehicle body B1 in a state where movement in the left - right direction Y is restricted and is movable in the front - rear direction X. The torsion bar 12 is provided at the center portion in the left - right direction Y of each of the vehicle body B1 and the axle W. Note that the torsion bar 12 may be provided at a position away from the center portion in the left - right direction Y of each of the vehicle body B1 and the axle W in the left - right direction Y.

[0020] The torsion bar 12 extends straight in the front - rear direction X as viewed from the up - down direction Z. The torsion bar 12 extends upward as it goes forward. Note that the torsion bar 12 may extend toward the left side or the right side as it goes forward, or may extend downward as it goes forward, and may be provided such that the position in the vertical direction Z remains the same over the entire length in the front-rear direction X.

[0021] In the illustrated example, the rear end portion of the torsion bar 12 is fixed to the axle W, and the front end portion of the torsion bar 12 is supported by the vehicle body B1. The rear end portion of the torsion bar 12 is fixed to the axle W by, for example, welding or fastening members. Note that the rear end portion of the torsion bar 12 may be rotatably supported by the axle W about an axis extending in the left-right direction Y. Also, the front end portion of the torsion bar 12 may be supported by the axle W, and the rear end portion of the torsion bar 12 may be supported by the vehicle body B1.

[0022] The suspension device 1 includes a support cylinder 15 in which the front end portion (the other end portion) of the torsion bar 12 is slidably fitted in the front-rear direction X. The support cylinder 15 is connected to the vehicle body B1 so as to be swingable in the front-rear direction X about a rotation axis O3 extending in the left-right direction Y. The rotation axis O3 is located above the support cylinder 15. The support cylinder 15 and the torsion bar 12 are disposed coaxially with a common axis O4 extending in the front-rear direction X. Note that the support cylinder 15 and the torsion bar 12 may be provided with anti-disengagement portions that engage with each other to prevent the torsion bar 12 from disengaging from the support cylinder 15 in the front-rear direction X.

[0023] A supported protrusion 16 protruding upward is formed at the upper end portion of the support cylinder 15. The vehicle body B1 is provided with a pair of support protrusions 17 that protrude downward and sandwich the supported protrusion 16 in the left-right direction Y. The upper portions of the pair of support protrusions 17 are connected to each other in the left-right direction Y. The supported protrusion 16 and the pair of support protrusions 17 are integrally penetrated in the left-right direction Y by a rotating shaft 18 disposed coaxially with the rotation axis O3. When the supported protrusion 16 rotates about the rotation axis O3 with respect to the pair of support protrusions 17, the support cylinder 15 swings in the front-rear direction X about the rotation axis O3 with respect to the vehicle body B1.

[0024] The cross-sectional shape of the outer peripheral surface of the torsion bar 12 is angular, or oval-shaped that is long in the left-right direction Y, or elliptical. In the illustrated example, the cross-sectional shape of the outer peripheral surface of the torsion bar 12 is rectangular, which is formed by four sides. Among these four sides, a pair of sides extends in the left-right direction Y, and the remaining pair of sides extends in the up-down direction Z. Note that the cross-sectional shape of the outer peripheral surface of the torsion bar 12 may be, for example, angular that is long in the left-right direction Y, or circular.

[0025] The front end portion of the torsion bar 12 is fitted slidably in the front-rear direction X within the support cylinder 15 in a state where rotational movement in the direction of orbiting the common axis O4 is restricted. In the illustrated example, the cross-sectional shape of the inner peripheral surface of the support cylinder 15 is the same as the cross-sectional shape of the outer peripheral surface of the torsion bar 12. Note that when the cross-sectional shapes of the inner peripheral surface of the support cylinder 15 and the outer peripheral surface of the torsion bar 12 are both circular, uneven portions may be separately formed on the inner peripheral surface of the support cylinder 15 and the outer peripheral surface of the torsion bar 12 so as to restrict relative rotation in the direction of orbiting the common axis O4 between the support cylinder 15 and the torsion bar 12 by meshing with each other.

[0026] When the vehicle body B1 and the axle W move relative to each other in the up-down direction Z, the first ball portion 13 rotates around the first axis O1, and while the second ball portion 14 swings in the front-rear direction X around the axis located above the second axis O2, the leaf spring 11 deflects and deforms in the up-down direction Z and expands and contracts in the front-rear direction X.

[0027] As described above, according to the suspension device 1 of the present embodiment, the rear end portion of the torsion bar 12 is supported by the axle W in a state where movement in the front-rear direction X and the left-right direction Y is restricted, and the front end portion of the torsion bar 12 is supported by the vehicle body B1 in a state where movement in the left-right direction Y is restricted and is movable in the front-rear direction X. Therefore, when the vehicle body B1 and the axle W move relative to each other in the vertical direction Z while causing the leaf spring 11 to deflect and deform in the vertical direction Z, the front end of the torsion bar 12 can be moved in the front-rear direction X with respect to the vehicle body B1 following the expansion and contraction deformation of the leaf spring 11 in the front-rear direction X, and the leaf spring 11 can be deformed as designed. As a result, when the vehicle body B1 and the axle W move relative to each other in the vertical direction Z, it becomes possible to smoothly move the vehicle body B1 and the axle W relative to each other in the front-rear direction Z, and deterioration in the riding comfort can be prevented.

[0028] Since the support cylinder 15 in which the front end of the torsion bar 12 is fitted so as to be slidable in the front-rear direction X is connected to the vehicle body B1 so as to be swingable in the front-rear direction X around the rotation axis O3 extending in the left-right direction Y, when the vehicle body B1 and the axle W move relative to each other in the vertical direction Z, while swinging the support cylinder 15 in the front-rear direction X around the rotation axis O3, the front end of the torsion bar 12 can be slid in the front-rear direction X with respect to the support cylinder 15, the frictional force generated between the support cylinder 15 and the front end of the torsion bar 12 is suppressed, and the vehicle body B1 and the axle W can be moved relative to each other more smoothly in the front-rear direction X.

[0029] Since the cross-sectional shape of the outer peripheral surface of the torsion bar 12 is angular, or oval-shaped long in the left-right direction Y, or elliptical, the torsional rigidity of the torsion bar 12 is increased, the roll rigidity and lateral rigidity between the vehicle body B1 and the axle W can be improved, and the rotational movement of the torsion bar 12 along the common axis O4 with respect to the support cylinder 15 can be easily restricted, and the roll rigidity can be surely improved.

[0030] Note that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0031] For example, the support cylinder 15 may be fixed to the vehicle body B1. Either the front end or the rear end of the torsion bar 12 may be supported by the vehicle body B1 so as to be swingable in the front-rear direction X via a connecting piece extending in the vertical direction Z. In this configuration, the upper end of the connecting piece is rotatably connected to the vehicle body B1 about a rotation axis extending in the left-right direction Y, and the lower end of the connecting piece is rotatably connected to the other end of the torsion bar 12 about a rotation axis extending in the left-right direction Y.

[0032] In addition, within the scope not departing from the gist of the present invention, it is possible to appropriately replace the components in the above-described embodiment with well-known components, and the above-described embodiment and modification examples may be appropriately combined.

Explanation of Reference Numerals

[0033] 1 Suspension device 11 Leaf spring 12 Torsion bar 15 Support cylinder B1 Vehicle body O1 First axis (axis) O3 Rotation axis W Axle X Front-rear direction Y Left-right direction Z Vertical direction

Claims

1. A pair of left and right leaf springs that extend in the front-rear direction, are attached to the vehicle body, and support the axle, and A torsion bar that extends in the front-rear direction and has one end of either the front end or the rear end supported by the axle in a state where movement in the front-rear direction and the left-right direction is restricted, One end of either the front end or the rear end of the leaf spring is rotatably connected to the vehicle body about an axis extending in the left-right direction, and the other end is swingably connected to the vehicle body about an axis extending in the left-right direction in the front-rear direction, The other end of either the front end or the rear end of the torsion bar is movably supported in the front-rear direction by the vehicle body in a state where movement in the left-right direction is restricted. A suspension device.

2. The other end of the torsion bar is provided with a support cylinder that is slidably fitted in the front-rear direction, The support cylinder is swingably connected to the vehicle body about a rotational axis extending in the left-right direction in the front-rear direction. The suspension device according to claim 1.

3. The cross-sectional shape of the outer peripheral surface of the torsion bar is angular, or oblong in the left-right direction, or elliptical. The suspension device according to claim 1 or 2.

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