JP6136523B2 - Torsion beam suspension - Google Patents

Description

  The present invention relates to a torsion beam suspension.

  In order to improve the fuel efficiency of automobiles, there is a demand for lighter vehicles. Therefore, the application of aluminum alloys is being promoted for undercarriage parts. A torsion beam suspension, which is an underbody part, includes a torsion beam and a pair of trailing arms joined to respective ends of the torsion beam by welding. Each of the trailing arms is required to have high rigidity against lateral force, longitudinal force, and vertical force applied to the vehicle, while the torsion beam generates a torsional load when the left and right wheels are displaced in the opposite phase. Appropriate rigidity is required to support it.

  Therefore, a torsion beam suspension is known in which stress generated at the edge portion of the torsion beam is reduced while avoiding an increase in weight. This conventional torsion beam type suspension includes a torsion beam inserted into a trailing arm (see, for example, Patent Document 1).

JP 2012-140031 A

  In the conventional torsion beam type suspension, an overlapping portion of the trailing arm and the torsion beam occurs due to the structure in which the torsion beam is inserted into the trailing arm. This overlap is an extra weight increase for the trailing arm or torsion beam.

  Further, since the diameter dimensions of the trailing arm and the torsion beam are inevitably different, a step is generated in the overlapping portion. This step causes a disadvantage in strength due to stress concentration.

  Further, since there are unwelded portions at the trailing arm, the torsion beam, and the edge portion, the boundary between the welded portion and the unwelded portion causes a disadvantage in strength due to stress concentration. The unwelded part is also exposed to fretting fatigue by a minute reciprocating sliding motion.

  In addition, when welding the trailing arm and the torsion beam, it is difficult to increase the positioning accuracy in the length direction of the torsion beam.

  Accordingly, an object of the present invention is to provide a high-productivity torsion beam suspension that can more reliably avoid an increase in weight, relieve stress concentration at a joint portion between a trailing arm and a torsion beam, and can be easily positioned. To do.

In order to solve the above problems, a torsion beam suspension according to the present invention includes a plate-like torsion beam that opens in one direction, or a tubular long torsion beam that opens in one direction, and both ends of the torsion beam. A pair of trailing arms coupled to the torsion beam, the trailing arm having a hollow beam joint joined to the torsion beam, and a joint portion between the trailing arm and the torsion beam Inclined with respect to a reference line extending in the longitudinal direction of the torsion beam, the end of the torsion beam becomes narrower from the non-open side to the open side in the open shape, and the end of the beam junction is the end of the torsion beam A concave surface that has an inclined surface that follows the shape of the part and that is recessed in the inclined surface. Ru equipped with.
The torsion beam suspension according to the present invention is a pair of plates connected to both ends of the plate-like torsion beam having an open shape opened in one direction or a tubular long torsion beam having an open shape opened in one direction. The trailing arm includes a hollow-structure beam joint that is joined to the torsion beam so that the thickness of the beam joint is gradually or gradually away from the torsion beam. Thick.

  According to the present invention, it is possible to provide a highly productive torsion beam suspension capable of avoiding an increase in weight more reliably, relieving stress concentration at a joint portion between a trailing arm and a torsion beam, and easily positioning.

1 is a perspective view showing a vehicle to which a torsion beam suspension according to an embodiment of the present invention is applied. The perspective view which shows the torsion beam type suspension which concerns on embodiment of this invention. The disassembled perspective view which shows the torsion beam type suspension which concerns on embodiment of this invention. The figure which shows the load which acts on the torsion beam type suspension which concerns on embodiment of this invention. The cross-sectional view showing an example of the torsion beam according to the embodiment of the present invention. The cross-sectional view showing an example of the torsion beam according to the embodiment of the present invention. The cross-sectional view showing an example of the torsion beam according to the embodiment of the present invention. The cross-sectional view showing an example of the torsion beam according to the embodiment of the present invention. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention along a reference line. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. The perspective view which shows the trailing arm of the torsion beam type suspension which concerns on embodiment of this invention. Sectional drawing which shows the other example of the torsion beam type suspension which concerns on embodiment of this invention along a reference line. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. Sectional drawing which shows the torsion beam type suspension which concerns on embodiment of this invention. The perspective view which shows the trailing arm of the torsion beam type suspension which concerns on embodiment of this invention. The cross-sectional view showing an example of the trailing arm according to the embodiment of the present invention. The cross-sectional view showing an example of the trailing arm according to the embodiment of the present invention. Sectional drawing which shows the other example of the torsion beam type suspension which concerns on embodiment of this invention along a reference line. Sectional drawing which shows the other example of the torsion beam type suspension which concerns on embodiment of this invention along a reference line.

  An embodiment of a torsion beam suspension according to the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view showing a vehicle to which a torsion beam suspension according to an embodiment of the present invention is applied.

  As shown in FIG. 1, an automobile 1 as a vehicle according to this embodiment includes a torsion beam suspension 2 (hereinafter simply referred to as “suspension 2”) as a rear suspension. The suspension 2 supports a pair of left and right wheels 3.

  The suspension 2 swings in the vertical direction of the automobile 1. The suspension 2 includes a long torsion beam 5 and a pair of trailing arms 6 connected to both ends of the torsion beam 5.

  The torsion beam 5 extends in the left-right direction (vehicle width direction) of the automobile 1.

  The trailing arm 6 is connected to the torsion beam 5 and extends in the vehicle width direction and is divided into two forks. Each branch extends forward and rearward of the vehicle.

  The suspension spring 7 and the shock absorber 8 support the vertical force of the automobile 1 loaded on the suspension 2.

  FIG. 2 is a perspective view showing a torsion beam suspension according to the embodiment of the present invention.

  FIG. 3 is an exploded perspective view showing the torsion beam type suspension according to the embodiment of the present invention.

  As shown in FIGS. 2 and 3, the suspension 2 according to the present embodiment is swingably supported by a bracket 9 provided on the vehicle body. The suspension 2 supports the wheel 3 via the hub 11. A brake drum 12 is sandwiched between the hub 11 and the wheel 3.

  The trailing arm 6 is made of a non-ferrous alloy casting such as an aluminum alloy. The torsion beam 5 is an aluminum alloy or iron alloy extruded material or a molded product of a plate material.

  The trailing arm 6 includes a beam joint 13 that is joined to the torsion beam 5 in abutment. The trailing arm 6 is bifurcated from the beam joint 13. Each branch has an arc shape R continuous from the beam junction 13. This arc is more preferable as the curvature is smaller (the curvature radius is larger). Here, one branch extending forward of the vehicle is referred to as a front arm 15, and the other branch extending rearward of the vehicle is referred to as a rear arm 16.

  The front arm 15 includes a bush press-fit portion 17. An elastic tubular bush 18 is press-fitted into the bush press-fit portion 17. The bush 18 is swingably supported by the bracket 9 with a bolt 21. The bracket 9, the bush 18, and the bush press-fit portion 17 are swing axes of the suspension 2.

  The rear arm 16 includes an absorber mounting portion 22, a spring seat 23, and a carrier 25.

  The absorber mounting portion 22 is provided on the surface of the rear arm 16 that faces the torsion beam 5, that is, on the inner side when viewed in the vehicle width direction of the automobile 1. The absorber mounting portion 22 supports the lower end portion of the shock absorber 8 so as to be swingable. The shock absorber 8 is swingably supported by the absorber mounting portion 22 with a bolt 26.

  The spring seat 23 extends from the beam joint 13 to the rear arm 16. The spring seat 23 is also provided inside as viewed in the vehicle width direction of the automobile 1. The spring seat 23 is applied to the lower end of the suspension spring 7. The upper end of the suspension spring 7 is applied to and supports the body frame of the automobile 1.

  The carrier 25 is provided on the surface opposite to the surface facing the torsion beam 5, that is, the surface facing the outside as viewed in the vehicle width direction of the automobile 1. The carrier 25 supports the wheel 3 via the hub 11.

  A joint portion 27 between the trailing arm 6 and the torsion beam 5 is inclined with respect to a reference line B extending in the longitudinal direction of the torsion beam 5.

  FIG. 4 is a diagram showing a load acting on the torsion beam suspension according to the embodiment of the present invention.

  As shown in FIG. 4, the suspension 2 according to the present embodiment is supported by a bracket 9 so as to be swingable in the vertical direction of the automobile 1. The suspension 2 is positioned in the vertical direction of the automobile 1 by the suspension spring 7 and the shock absorber 8.

  The torsion beam 5 is subjected to lateral force, front / rear force, and vertical force acting from the installation point of the wheel 3 and a roll load that acts when the pair of left and right wheels 3 are displaced in opposite phases in the vertical direction. .

  FIG. 5 is a cross-sectional view showing an example of a torsion beam according to an embodiment of the present invention.

  FIG. 6 is a cross-sectional view showing an example of a torsion beam according to an embodiment of the present invention.

  FIG. 7 is a cross-sectional view showing an example of a torsion beam according to an embodiment of the present invention.

  As shown in FIGS. 5 to 7, the trailing arm 6 of the suspension 2 according to the present embodiment exhibits an open shape that is open in one direction in a cross-sectional shape, that is, a cross-sectional shape in a direction orthogonal to the reference line B. It is a plate-shaped beam. Specifically, the trailing arm 6 has a U-shaped (FIG. 5), a V-shaped (FIG. 6), and a C-shaped (FIG. 7) cross-sectional shape.

  FIG. 8 is a cross-sectional view showing an example of a torsion beam according to an embodiment of the present invention.

  As shown in FIG. 8, the trailing arm 6 may be a tubular beam having an open shape that opens in one direction in a cross-sectional shape, that is, a cross-sectional shape in a direction perpendicular to the reference line B. Specifically, the trailing arm 6 exhibits a U-shaped cross-sectional shape by plastic working such as crushing a tube having a circular cross-sectional shape, for example.

  The following description is represented by the trailing arm 6 having a U-shaped cross section.

  FIG. 9 is a sectional view showing a torsion beam suspension according to the embodiment of the present invention along a reference line.

  FIG. 10 is a cross-sectional view showing the torsion beam suspension according to the embodiment of the present invention, taken along line XX in FIG.

  FIG. 11 is a cross-sectional view showing the torsion beam suspension according to the embodiment of the present invention, taken along the line XI-XI in FIG.

  FIG. 12 is a cross-sectional view showing the torsion beam suspension according to the embodiment of the present invention, taken along line XII-XII in FIG.

  FIG. 13 is a cross-sectional view showing the torsion beam suspension according to the embodiment of the present invention, taken along line XIII-XIII in FIG.

  FIG. 14 is a perspective view showing a trailing arm of the torsion beam suspension according to the embodiment of the present invention.

As shown in FIGS. 9 to 13, the beam joint portion 13 of the suspension 2 according to the present embodiment has a substantially uniform hollow structure and has a closed cross-sectional shape, while the torsion beam 5 of the suspension 2 is unidirectional. It is a plate-like beam having an open shape that opens to the top. The opening direction of the torsion beam 5 faces the lower side of the automobile 1, that is, the road surface direction.

  Further, the end surface of the torsion beam 5 is tilted toward the vehicle center side with respect to the plane orthogonal to the reference line B.

  The inclination of the joint portion 27 is on the center side in the longitudinal direction of the torsion beam 5 (from the left in FIG. 4) on the non-open side C than on the open side O in the open shape of the torsion beam 5. In other words, the end of the torsion beam 5 tapers from the non-open side C toward the open side O in the open shape. On the other hand, the end of the beam joint 13 becomes thicker from a position corresponding to the non-open side C of the torsion beam 5 toward a position corresponding to the open side O of the torsion beam 5. The end of the beam joint 13 includes an inclined surface 28 that is inclined following the shape of the end of the torsion beam 5.

  A convex portion 29 into which the end portion of the torsion beam 5 is fitted is provided at the end portion of the beam joint portion 13. The convex portion 29 only needs to have a minimum protrusion amount required for positioning and joining of the beam joining portion 13 and the torsion beam 5. In the state where the torsion beam 5 is fitted to the convex portion 29, the end surface of the torsion beam 5 abuts against the end portion of the beam joint portion 13, while the outer surfaces of the torsion beam 5 and the beam joint portion 13 are substantially flush. The joint portion 27 is joined over the entire circumference by welding or friction stir welding, and the torsion beam 5 and the trailing arm 6 are integrated.

  The suspension 2 having the above-described configuration has an open cross-sectional shape and a relatively low rigidity torsion beam 5 toward a closed cross-sectional shape and a relatively high rigidity trailing arm 6 (specifically, the beam joint 13). The sectional area of the trailing arm 6 gradually increases, and a sudden change in rigidity at the joint portion 27 between the torsion beam 5 and the trailing arm 6 can be suppressed.

  Next, another example of the suspension 2 according to the embodiment will be described. In the suspensions 2A, 2B, and 2C described in each example, the same components as those in the suspension 2 are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 15 is a cross-sectional view showing another example of the torsion beam suspension according to the embodiment of the present invention along the reference line.

  FIG. 16 is a cross-sectional view showing the torsion beam suspension according to the embodiment of the present invention, taken along the line XVI-XVI of FIG.

  FIG. 17 is a cross-sectional view showing the torsion beam suspension according to the embodiment of the present invention, taken along line XVII-XVII in FIG.

  18 is a cross-sectional view showing the torsion beam type suspension according to the embodiment of the present invention, taken along the line XVIII-XVIII in FIG.

  FIG. 19 is a cross-sectional view of the torsion beam suspension according to the embodiment of the present invention, taken along line XIX-XIX in FIG.

  FIG. 20 is a cross-sectional view showing the torsion beam suspension according to the embodiment of the present invention, taken along the line XX-XX in FIG.

  FIG. 21 is a perspective view showing the trailing arm of the torsion beam suspension according to the embodiment of the present invention.

  As shown in FIGS. 14 to 21, the suspension 2 </ b> A according to the present embodiment includes a recessed portion 31 that is recessed in the inclined surface 28 of the beam joint portion 13.

  The recess 31 has a shape that gradually increases the depth h1 of the depression from the edge P farthest from the torsion beam 5 to the tip Q of the torsion beam 5 when viewed in the longitudinal direction of the torsion beam 5. It has a shape that gradually reduces the depth h2 of the recess to the tip R of the beam joint portion 13.

  In addition, the recess 31 has an arc shape in a cross section orthogonal to the reference line B.

  FIG. 22 is a cross-sectional view showing an example of a trailing arm according to an embodiment of the present invention.

  FIG. 23 is a cross-sectional view showing an example of a trailing arm according to an embodiment of the present invention.

  As shown in FIGS. 22 and 23, the recess 31 of the suspension 2A according to the present embodiment has a rectangular shape (FIG. 22) in addition to the circular arc shape in the cross-sectional shape, that is, the cross-sectional shape in the direction orthogonal to the reference line B. ) Or a V-shaped (FIG. 23) cross-sectional shape.

  The suspension 2 </ b> A having such a configuration includes a recess 31 on the inclined surface 28 of the trailing arm 6, so that the trailing toward the trailing arm 6 (specifically, the beam joining portion 13) from the torsion beam 5 compared to the suspension 2. The amount of increase in the cross-sectional area and the amount of change in the cross-sectional area of the arm 6 can be made duller and gentle so that a sudden change in rigidity at the joint portion 27 between the torsion beam 5 and the trailing arm 6 can be further suppressed.

  FIG. 24 is a sectional view showing another example of the torsion beam suspension according to the embodiment of the present invention along the reference line.

  As shown in FIG. 24, the thickness of the beam joint 13 of the suspension 2 </ b> B according to this embodiment increases gradually or stepwise as the distance from the torsion beam 5 increases. The thickness of the beam joining portion 13 is the thinnest at the tip R, and gradually or stepwise increases from the torsion beam 5 to the edge P of the concave portion 31 farthest from the torsion beam 5, and is approximately the same as the other portions of the trailing arm 6. Reach the thickness of.

  The suspension 2B includes the concave portion 31 as in the case of the suspension 2A. However, the suspension 2B may include a flat inclined surface 28 like the suspension 2.

  In the suspension 2B having such a configuration, the thickness of the beam joint 13 is gradually or stepwise increased as the distance from the torsion beam 5 increases, so that the trailing arm 6 (details) can be obtained from the torsion beam 5 compared to the suspensions 2 and 2A. The cross-sectional area increase amount and the cross-sectional area change amount of the trailing arm 6 toward the beam joint 13) side are further dulled and moderated, and a sudden rigidity change in the joint portion 27 between the torsion beam 5 and the trailing arm 6 is further increased. Can be suppressed.

  FIG. 25 is a cross-sectional view showing another example of the torsion beam suspension according to the embodiment of the present invention along the reference line.

  As shown in FIG. 25, the thickness of the beam joint 13 of the suspension 2 </ b> C according to the present embodiment is the first region A <b> 1 corresponding to the joint portion 27 of the trailing arm 6 and the torsion beam 5 in the longitudinal direction of the torsion beam 5. The second region A2 outside the first region A1 and corresponding to the recess 31 is different from the third region A3 other than the first region A1 and the second region A2.

  The first region A1 is a section from the tip R of the beam joint 13 to the tip Q of the torsion beam 5, and the second region A2 is an edge P farthest from the torsion beam 5 in the recess 31 from the tip Q of the torsion beam 5. The third region A3 is a section on the outer side in the vehicle width direction from the edge portion P and is a root portion of the beam joint portion 13.

  The thickness of the first region A1 is the thinnest, and the thickness of the third region A3 is the thickest. The first region A1 and the third region A3 have a substantially uniform thickness.

  The thickness of the second region A2 changes gradually or stepwise within the difference between the thickness of the first region A1 and the thickness of the third region A3.

  The suspension 2 </ b> C having such a configuration includes the second region A <b> 2 accompanied by a change in thickness and consequently a change in rigidity, so that a stress generated in the joint portion 27 of the trailing arm 6 and the torsion beam 5, i.e., the first region A <b> 1. To the second region A2 and, consequently, the stress concentration portion S is moved to the second region A2 to reduce the load burden on the joint portion 27 between the trailing arm 6 and the torsion beam 5 (in FIG. 25, two-dot chain line S1). To the two-dot broken line S2.) In particular, when the thickness of the second region A2 is rapidly changed in a portion close to the third region A3, this effect becomes remarkable.

  Since the suspensions 2, 2A, 2B, and 2C according to the present embodiment are bonded to the trailing arm 6 by abutting the torsion beam 5, the suspensions can be reliably reduced in weight and easily positioned.

  Further, the suspensions 2, 2A, 2B, and 2C according to the present embodiment can moderate the stress concentration by moderately suppressing the rigidity change in the joint portion 27 by inclining the joint portion 27.

  Furthermore, since the suspensions 2, 2A, 2B, and 2C according to the present embodiment join the joint portion 27 over the entire circumference, there is no boundary between the welded portion and the unwelded portion, stress concentration is suppressed, and fretting fatigue Is avoided.

  Furthermore, the suspensions 2, 2A, 2B and 2C according to the present embodiment can alleviate stress concentration near the outer surface because the outer surface of the joint portion 27 is substantially flush. In addition, although a level | step difference arises between the inner surface of the torsion beam 5 and the inclined surface 28 of the trailing arm 6, a stress value is lower than the outer surface side and it does not become a problem.

  In the suspensions 2, 2A, 2B, and 2C according to the present embodiment, the beam joint 13 and the front arm 15 and the beam joint 13 and the rear arm 16 have arc shapes, respectively. Therefore, the load can be smoothly transmitted from the bush press-fitting portion 17, the absorber mounting portion 22, the spring seat 23, and the carrier 25 to the torsion beam 5, and the stress concentration can be reduced.

  Furthermore, since the suspensions 2, 2A, 2B, and 2C according to the present embodiment include the torsion beam 5 having an open shape that opens in one direction, the suspensions 2, 2A, 2B, and 2C can be applied to a vehicle type that does not require much torsional rigidity.

  Furthermore, in the suspension 2 </ b> C according to the present embodiment, when the joint portion 27 has an aluminum alloy welded structure, the joint portion 27 of the aluminum alloy, whose material strength is likely to decrease, and the stress concentration portion are separated from each other. The stress concentration at can be relaxed.

  Therefore, according to the suspensions 2, 2A, 2B, and 2C according to the present embodiment, an increase in weight is more reliably avoided, stress concentration at the joint portion 27 between the trailing arm 6 and the torsion beam 5 is reduced, and positioning is easily performed. It becomes possible.

1 Car 2, 2A, 2B, 2C Torsion beam type suspension 3 Wheel 5 Torsion beam 6 Trailing arm 7 Suspension spring 8 Shock absorber 9 Bracket 11 Hub 12 Brake drum 13 Beam joint 15 Front arm 16 Rear arm 17 Bush press-fit part 18 Bush 21 Bolt 22 Absorber mounting part 23 Spring seat 25 Carrier 26 Bolt 27 Joint part 28 Inclined surface 29 Convex part 31 Concave part

Claims (13)

A plate-like shape having an open shape that opens in one direction, or a tubular long torsion beam that has an open shape that opens in one direction; and
A pair of trailing arms connected to both ends of the torsion beam,
The trailing arm includes a beam joint having a hollow structure that is joined to the torsion beam .
A joint portion of the trailing arm and the torsion beam is inclined with respect to a reference line extending in a longitudinal direction of the torsion beam;
The end of the torsion beam becomes narrower from the non-open side to the open side in the open shape,
The end of the beam joint includes an inclined surface that is inclined following the shape of the end of the torsion beam,
Torsion beam suspension of Ru with a recess recessed in the inclined surface. 2. The torsion beam suspension according to claim 1 , wherein the inclination is on the center side in the longitudinal direction of the torsion beam on the non-open side than on the open side in the open shape. 3. The torsion beam suspension according to claim 1, wherein a thickness of the beam joint is gradually or stepwise increased as the distance from the torsion beam increases. In the longitudinal direction of the torsion beam, the thickness of the beam joining portion includes a first region corresponding to a joint portion between the trailing arm and the torsion beam, and a second region outside the first region and corresponding to the recess. The region and the third region other than the first region and the second region, the thickness of the first region is the thinnest, the thickness of the third region is the thickest, The torsion beam suspension according to claim 1 or 2 , wherein the wall thickness changes gradually or stepwise within a difference between the wall thickness of the first region and the wall thickness of the third region. Torsion beam suspension according to claim 1 or 2, wherein the recess exhibits a rectangular cross-sectional shape. Torsion beam suspension according to claim 1 or 2, wherein the recess exhibits a cross-sectional shape of the V-shape. A plate-like shape having an open shape that opens in one direction, or a tubular long torsion beam that has an open shape that opens in one direction; and
A pair of trailing arms connected to both ends of the torsion beam,
The trailing arm includes a beam joint having a hollow structure that is joined to the torsion beam.
The thickness of the beam joint is a torsion beam type suspension that gradually or gradually increases as the distance from the torsion beam increases. The torsion beam type suspension according to claim 7, wherein a joint portion between the trailing arm and the torsion beam is inclined with respect to a reference line extending in a longitudinal direction of the torsion beam. The torsion beam suspension according to claim 8, wherein the inclination is on the center side in the longitudinal direction of the torsion beam on the non-open side than on the open side in the open shape. The end of the torsion beam becomes narrower from the non-open side to the open side in the open shape,
11. The torsion beam suspension according to claim 9, wherein an end of the beam joint includes an inclined surface that is inclined in accordance with an end shape of the torsion beam. The torsion beam suspension according to any one of claims 1 to 10 , wherein the beam joint portion has a closed cross-sectional shape. The torsion beam suspension according to any one of claims 1 to 11 , wherein the trailing arm is bifurcated from the beam joint, and each branch has an arc shape continuous from the beam joint. The trailing arm is made of a non-ferrous alloy casting,
The torsion beam suspension according to any one of claims 1 to 12 , wherein the torsion beam is an extruded product of aluminum alloy or iron alloy or a molded product of a plate material.

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