JP2011105199A - Torsion beam type suspension of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a vehicle possess proper roll rigidity by a constitution which hardly causes an increase in weight while securing the rigidity of a torsion beam even if the torsion beam is short in length. <P>SOLUTION: This torsion beam type suspension of the vehicle includes a right/left pair of trailing arms 31 extending in the front/rear direction of the vehicle and arranged swingingly in the vertical direction of the vehicle for suspending a wheel, and the torsion beam 41 extending in the width direction of the vehicle and disposed between the right/left pair of trailing arms. The swinging portion of the trailing arm 31 and the end of the torsion beam 41 are connected through a bush. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a torsion beam suspension for a vehicle. Specifically, the pair of left and right trailing arms that extend in the vehicle front-rear direction and are swingably disposed in the vehicle vertical direction to suspend the wheels and extend between the pair of left and right trailing arms that extend in the vehicle width direction. The present invention relates to a torsion beam suspension for a vehicle including a torsion beam.

  In this type of suspension, a trailing arm connected to a vehicle body and wheels and a torsion beam are conventionally welded, and the vehicle is allowed to roll to some extent when the torsion beam and the trailing arm are twisted or bent. It was a composition. Therefore, the rigidity (roll rigidity) when the vehicle rolls has been optimized by adjusting the torsional rigidity and the bending rigidity by designing the materials and shapes of the torsion beam and the trailing arm.

  Patent Document 1 below proposes another structure of a torsion beam suspension. In the suspension of Patent Document 1 below, left and right trailing arms are provided with beam pieces extending along the vehicle width direction. Then, with the left and right beam pieces partially overlapping vertically, the middle of the left beam piece and the middle of the right beam piece and the middle of the right beam piece and the left beam piece are in the vehicle width direction. The shafts are connected so as to be rotatable relative to each other via a rubber bush. The connected left and right beam pieces constitute a torsion beam. According to this suspension, the relative rotation of the left and right beam pieces is allowed by the elasticity of the rubber bush, so that the vehicle can have an appropriate roll rigidity even if the beam pieces themselves are not twisted or bent. .

JP 2008-201241 A

  By the way, for example, if a torsion beam suspension is adopted in a narrow tread vehicle such as a single-seat vehicle, the torsion beam becomes shorter, and if the strength of the torsion beam is secured, the torsional rigidity and the bending rigidity increase, and the vehicle rolls. Increased rigidity. Therefore, it has been difficult to achieve both strength securing and optimization of vehicle roll rigidity only by changing the design of the material and shape of the torsion beam. Therefore, if the suspension structure of Patent Document 1 that can provide appropriate roll rigidity without requiring twisting or bending of the beam piece can be applied to a vehicle having a narrow tread, the strength of the left and right beam pieces can be reduced. In other words, the vehicle may have an appropriate roll rigidity. However, because part of the left and right beam pieces are overlapped, it is unclear whether the overlap length can be properly secured, and even if the overlap length can be secured appropriately, it causes an increase in weight. It is not preferable.

  Accordingly, an object of the present invention is to enable a vehicle to have an appropriate roll rigidity while ensuring the strength of the torsion beam, even when the torsion beam is short, with a configuration that does not easily increase the weight. .

  The present invention includes a pair of left and right trailing arms that extend in the vehicle front-rear direction and are swingable in the vehicle vertical direction to suspend a wheel, and extend between the pair of left and right trailing arms that extend in the vehicle width direction. A torsion beam suspension of a vehicle including the torsion beam, wherein a swinging portion of the trailing arm and an end of the torsion beam are connected via a bush.

  According to such a torsion beam suspension of a vehicle, when the torsion beam is short and securing the strength of the torsion beam, it is difficult to reduce the torsional rigidity and bending rigidity of the torsion beam. By deforming the bush connecting the arm and the torsion beam, the torsion beam is allowed to rotate or displace relative to the trailing arm. Therefore, the apparent torsional rigidity and bending rigidity of the entire suspension can be reduced, and the roll rigidity of the vehicle can be optimized.

  In the vehicle torsion beam suspension according to the present invention, the bush is cylindrical, and the axial direction of the cylindrical bush coincides with the tangential direction of the virtual circle around the axis of the torsion beam extending in the vehicle width direction. And preferred. Since the spring constant of the cylindrical bush is lower in the axial direction than in the axial direction, relative rotation of the torsion beam with respect to the trailing arm is likely to be allowed. As a result, the apparent torsional rigidity of the suspension as a whole can be further reduced to optimize the roll rigidity of the vehicle.

According to the torsion beam type suspension of the vehicle of the present invention, it is possible to achieve both ensuring the strength of the torsion beam and providing the vehicle with an appropriate roll rigidity even when the torsion beam is short due to the configuration that does not easily increase the weight. It becomes.
Further, if the bush is cylindrical, and the axial direction of the cylindrical bush and the tangential direction of the virtual circle around the axis of the torsion beam extending in the vehicle width direction coincide, the apparent torsional rigidity of the suspension as a whole is obtained. The roll rigidity of the vehicle can be optimized by lowering it better.

1 is a plan view of a torsion beam suspension of a vehicle according to an embodiment of the present invention. It is a side view of the torsion beam type suspension of the vehicle shown in FIG. It is a perspective view which expands and shows the connection structure of the torsion beam type suspension of the vehicle shown by FIG. FIG. 2 is an enlarged rear view showing a connection structure of the torsion beam suspension of the vehicle shown in FIG. 1. FIG. 5 is a cross-sectional view taken along line VV of the connection structure of the torsion beam suspension of the vehicle shown in FIG. 4. It is a figure which shows typically the relative positional relationship of the torsion beam and bush in the connection structure of the torsion beam type suspension of the vehicle of this embodiment in a side view. It is the figure shown corresponding to FIG. 6 about the modification 1 of this embodiment. It is the figure shown corresponding to Drawing 6 about modification 2 of this embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present embodiment is an example of an embodiment in which the torsion beam type suspension of the present invention is applied as a rear suspension in a small vehicle in which only one person can ride in the width direction.
A single-seat small vehicle (hereinafter sometimes simply referred to as a vehicle) 11 shown in FIG. 1 is an electric four-wheeled vehicle having rear wheels 13a and 13b as drive wheels. Note that Fr, Rr, L, and R indicated by arrows in each figure indicate the front, rear, left, and right sides of the vehicle 11. As shown in FIG. 1, at the rear of the vehicle 11, a pair of left and right side members 15 a and 15 b disposed as a frame structure 15 extending in the vehicle front-rear direction, and a rear disposed as extending in the vehicle width direction. A cross member 15c is provided. As shown in FIG. 2, the side member 15a includes a front horizontal portion 16a and a rear horizontal portion 16b arranged in a step at a relatively high position with respect to the front horizontal portion 16a via a vertical portion 16c. Are connected. As shown in FIG. 1, the rear cross member 15c is laid across the rear ends of the side members 15a and 15b to connect the side members 15a and 15b. A rear portion of the vehicle 11 is provided with a torsion beam suspension 21 that suspends the left and right rear wheels 13 a and 13 b from the frame structure 15 with appropriate rigidity. A driving device 19 is also provided at the rear of the vehicle 11. The drive device 19 includes an electric motor 19a and transmission members 19b and 19c that transmit the driving force of the electric motor 19a to the axles 14a and 14b of the rear wheels 13a and 13b.

  The torsion beam type suspension 21 includes a pair of left and right trailing arms 31 and 32 and a torsion beam 41. The trailing arms 31 and 32 are made of a hollow bar-shaped steel material having a rectangular cross section and are arranged extending in the vehicle front-rear direction. The torsion beam 41 is made of a hollow bar-shaped steel material having a rectangular cross section and is arranged extending in the vehicle width direction. The left and right end portions 41a and 41b of the torsion beam 41 are connected to the trailing end portions 31a and 32b of the trailing arms 31 and 32 by connecting structures 23a and 23b, which will be described in detail later. It is laid horizontally. The front end portions 31b and 32b of the trailing arms 31 and 32 are pivotally attached to the side members 15a and 15b so as to be swingable in the vehicle vertical direction. Specifically, as shown in FIG. 2, the front end portion 31b of the trailing arm 31 is pivotally attached to a bracket 16d provided on the vertical portion 16c of the side member 15b. Axle support brackets 31c and 32c are provided at positions close to the rear end portions 31a and 32a between the trailing arms 31 and 32, and the axles 14a and 14b are supported. As shown in FIG. 1, the torsion beam suspension 21 also includes a pipe-shaped lateral rod 25. The lateral rod 25 has one end portion 25a in the longitudinal direction connected to the left end portion 41a of the torsion beam 41, and the other end portion 25b positioned on the rear side of the axle 14b and the right side member 15b and the rear cross member 15c. Are connected to a connecting portion 17 provided at the joint portion. Therefore, in the torsion beam type suspension 21, the torsion beam 41 and the lateral rod 25 are disposed behind the axles 14a and 14b of the rear wheels 13a and 13b. In front of the rear wheels 13a and 13b in the vicinity of the axles 14a and 14b, coil springs 27 and 27 capable of exerting an elastic force in the vertical direction are provided between the middle of the trailing arms 31 and 32 and the side members 15a and 15b. Is being armed.

  The connecting structures 23a and 23b between the trailing arms 31 and 32 and the torsion beam 41 are the same on the left and right. Therefore, here, the left connecting structure 23a will be taken up and described in detail. As shown in FIGS. 3 and 4, the connection structure 23 a includes an arm-side connection bracket 33 that projects inward in the vehicle width direction at the rear end 31 a of the trailing arm 31, and ends of the torsion beam 41. The beam side connecting bracket 43 that is integrally provided so as to protrude outward in the vehicle width direction at the portion 41a is fastened by fasteners (bolts and nuts) 61 and 61 via bushes 51 and 51 (see FIG. 5). It becomes the composition.

  As shown in FIG. 3, the arm side connection bracket 33 is composed of a pair of front and rear plate members 35 and 37. The plate members 35 and 37 are disposed such that their plate surfaces face in the vehicle front-rear direction and are separated from each other in the front-rear direction. The plate-like members 35 and 37 have substantially the same shape, and as shown in FIG. 4, the vertical dimension is longer than the vertical dimension of the trailing arm 31. A notch 37a is formed by notching from the outer (left side) edge. The trailing arm 31 and the plate-like members 35 and 37 are welded in a state where the notch 37 a is fitted to the trailing arm 31. Therefore, the arm side connection bracket 33 protrudes inward in the vehicle width direction from the trailing arm 31 and also extends in the vertical direction. As shown in FIG. 5, two connecting hole portions 39a and 39b penetrating through the plate-like members 35 and 37 are provided at the end portion on the inner side in the vehicle width direction of the arm side connecting bracket 33 so as to be separated in the vertical direction. It has been. In addition, you may provide a reinforcing rib in the plate-shaped members 35 and 37 which comprise this arm side connection bracket 33 as needed.

  As shown in FIG. 3, the beam side connection bracket 43 includes a pair of upper and lower bracket pieces 45 and 47. The upper bracket piece 45 is erected on the upper surface of the beam side connection bracket 43, and protrudes upward from the beam side connection bracket 43 and extends outward in the vehicle width direction. The bracket piece 45 includes a base portion 45a welded to the torsion beam 41 and a cylindrical portion 45b provided to project outward in the vehicle width direction. When viewed from the rear, the base portion 45a has a shape in which the upper corner inside the rectangular vehicle width direction is missing, as shown in FIG. As shown in FIG. 3, the base 45 a is composed of a pair of plate-like portions 46 a and 46 b having such a shape. The plate-like portions 46a and 46b are spaced apart from each other in the vehicle front-rear direction, and an oblique side portion 46c on the inner side in the vehicle width direction is connected and formed. As shown in FIG. 5, the cylindrical portion 45b has an axial direction that coincides with the longitudinal direction of the vehicle, straddles the two plate-like portions 46a and 46b, and the vehicle width of the plate-like portions 46a and 46b. It joins to the edge part of the direction outward (refer FIG. 4). The lower bracket piece 47 has the same configuration as the upper bracket piece 45, is arranged vertically symmetrically with respect to the upper bracket piece 45, and hangs down from the lower surface of the torsion beam 41. Therefore, the beam-side connecting bracket 43 has two cylindrical portions 45b that are arranged symmetrically apart from each other in the vertical direction with the torsion beam 41 sandwiched between the end portion 41a of the torsion beam 41 and outward in the vehicle width direction. 47b. As shown in FIG. 5, the cylindrical portions 45 b and 47 b are shorter in the axial direction than the gap between the plate members 35 and 37 constituting the arm side connection bracket 33, and The plate-like members 35 and 37 are spaced apart from each other.

  The bush 51 includes a cylindrical inner cylinder 53 and an outer cylinder 55 that is coaxially disposed outside the inner cylinder 53, and is disposed between the inner cylinder 53 and the outer cylinder 55. A rubber elastic body 57 is provided in close contact with the outer surface and the inner surface of the outer cylinder 55. The inner cylinder 53 is thicker than the outer cylinder 55, and has a longer axial dimension than the outer cylinder 55 and the rubber elastic body 57, and its length dimension is a plate shape constituting the arm side connection bracket 33. The dimension is just within the gap between the members 35 and 37. The rubber elastic body 57 and the outer cylinder 55 have substantially the same axial dimension, and the dimension is substantially equal to the axial length of the cylindrical portions 45 b and 47 b of the beam side connection bracket 43.

  In the connection structure 23a, bushes 51 and 51 are coaxially press-fitted into the cylindrical portions 45b and 47b of the beam side connection bracket 43, and the inner cylinders 53 and 53 of the bushes 51 and 51 connect the arm side connection bracket 33 to each other. Between the plate-shaped members 35 and 37 which comprise, it arrange | positions coaxially with the connection hole parts 39a and 39b. And the plate-shaped members 35 and 37 which comprise the arm side connection bracket 33 in the state which interposed the inner cylinder 53 of the bush 51 are fastened with the volt | bolt nuts 61 and 61. FIG. Thus, the trailing arm 31 (see FIG. 4) and the torsion beam 41 are connected via the bushes 51 and 51.

  According to the torsion beam suspension 21 having the above configuration, the trailing arms 31 and 32 are allowed to rotate relative to the torsion beam 41 or be displaced in the vertical direction by deformation of the rubber elastic body 57 of the bush 51. Is done. This allows the left and right trailing arms 31 and 32 to swing independently to some extent. Therefore, even if it is difficult to reduce the torsional rigidity and the bending rigidity of the torsion beam 41, the torsion beam type suspension 21 as a whole can reduce the apparent torsional rigidity and the bending rigidity to give the vehicle 11 an appropriate roll rigidity. Can do. In particular, as shown in FIG. 6, the tangent line T of the virtual circle C around the axis of the torsion beam 41 and the axial direction of the bush 51 having a relatively low spring elastic modulus coincide with each other. It is easy to optimize the roll rigidity of the vehicle by lowering.

  It should be noted that various other embodiments can be considered within the scope of the present invention without departing from the gist of the present invention. For example, in order to make the tangent line T of the virtual circle C around the axis of the torsion beam 41 coincide with the axis of the bush 51, the bushes 51 and 51 are separated forward and backward with the torsion beam 41 in between, as illustrated in FIG. And may be arranged so that the axis is vertical (Modification 1). Further, as illustrated in FIG. 8, the bush 51 may be disposed obliquely in accordance with the tangent line T of the virtual circle C around the axis of the torsion beam 41 (Modification 2).

11 Vehicles 13a, 13b Rear wheels 14a, 14b Axle 15 Frame structure 21 Torsion beam suspensions 23a, 23b Connection structure 25 Lateral rod 31, 32 Trailing arm 33 Arm side connection bracket 41 Torsion beam 43 Beam side connection bracket 51 Bush 53 Inner cylinder 55 Outer cylinder 57 Rubber elastic body 61, 61 Bolt / Nut

Claims (2)

A pair of left and right trailing arms extending in the vehicle longitudinal direction and swingably arranged in the vehicle vertical direction and suspending wheels; and a torsion beam extending between the pair of left and right trailing arms extending in the vehicle width direction; A torsion beam suspension of a vehicle comprising:
A torsion beam type suspension for a vehicle, wherein a swinging part of the trailing arm and an end of the torsion beam are connected via a bush. A torsion beam suspension for a vehicle according to claim 1,
The bush is cylindrical, and the axial direction of the cylindrical bush and the tangential direction of a virtual circle around the axis of the torsion beam extending in the vehicle width direction coincide with each other. .

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