TWI486267B - Torsion beam, torsion beam assembly and torsion beam suspension - Google Patents

Description

Torsion beam, torsion beam assembly and torsion beam suspension device Field of invention

The invention relates to a torsion beam suspension device for automobiles, in particular to a torsion beam capable of suppressing metal fatigue, a torsion beam assembly having the torsion beam and a torsion beam type suspension device.

Background of the invention

As is well known, in the field of automobiles, torsion beam suspension devices are widely used. The torsion beam type suspension device includes a pair of right and left arm members and a torsion beam that connects the arm members to each other. Each of the arm members is configured such that the base end portion is rotatably coupled to the vehicle body, and the wheel is rotatably attached to the front end portion. A damper is attached between each arm member and the vehicle body. A spring receiving portion is provided in the vicinity of each end portion of the torsion beam, and a coil spring is disposed between the spring receiving portion and the vehicle body. The torsion beam is applied to the vehicle body by the main torsional stiffness of the torsion beam under the condition that the vehicle body is subjected to external force from the road surface. The torsion beam has a cross-sectional shape that can exhibit appropriate torsional rigidity in consideration of the roll stiffness of the vehicle body. Generally, the cross-sectional shape is formed to be symmetrical in the front-rear direction of the vehicle body (for example, refer to Patent Document 1).

Prior technical literature Patent literature

[Patent Document] Japanese Patent Laid-Open Publication No. 2005-306177

Summary of invention

According to the external force from the road surface, a complex stress distribution occurs in the torsion beam system, and the metal fatigue of the torsion beam is easy to develop according to the use condition of the vehicle.

The present invention is to solve such a conventional technical problem as a technical subject, and to provide a torsion beam for use as a suspension system for an automobile, which can effectively suppress metal fatigue, a torsion beam assembly having the torsion beam, and a torsion beam Suspension device for the purpose.

The inventors made a definitive study on the relationship between the torsional stiffness of the torsion beam and the stress distribution. For the cross-sectional shape in which the longitudinal direction of the torsion beam is perpendicular, it is found that by controlling the apex of the outer wall portion and the apex of the inner wall portion The relative position allows the stress distribution of the torsion beam to be changed as desired while maintaining the torsional stiffness of the torsion beam constant.

According to the present invention, the present invention is provided to be configured to be rotatably coupled to an automobile body in a vertical direction about a pivot axis at one end, and to be rotatable at an end portion on the opposite side of the end portion to which the automobile body is coupled A torsion beam for use in a vehicle suspension device for mounting a pair of arm members extending in the front-rear direction of the vehicle, the torsion beam having a recess extending in the longitudinal direction, whereby the torsion beam is perpendicular to the longitudinal direction The first and second leg portions in the plane and have an approximately V-shaped or approximately U-shaped cross-section The torsion beam system includes: a connecting portion provided at both ends of the torsion beam and coupled to the arm member; a fixed shape portion provided at a central portion of the torsion beam in a longitudinal direction; and a fixed shape portion provided in the fixed shape portion In the asymmetrical shape portion between the connecting portions, the recess has a certain depth in the fixed shape portion, and the first and second leg portions have approximately the same thickness or width dimension, and the asymmetric shape portion is in the asymmetrical shape portion. The depth of the recess is gradually deeper from the connecting portion toward the fixed shape portion, and the first leg portion has a torsion beam having a width larger than a width dimension of the second leg portion.

According to the torsion beam according to the present invention, the torsion beam is independently controlled independently of the value of the maximum principal stress occurring in the torsion beam and the torsional stiffness of the torsion beam, and the value of the maximum principal stress and the torsion beam stiffness can be effectively set. As a result, it is possible to reduce the value of the maximum principal stress of the torsion beam while ensuring the desired suspension performance, and to effectively reduce the metal fatigue occurring in the torsion beam.

According to the torsion beam, the torsion beam assembly and the torsion beam suspension device according to the present invention, the maximum principal stress occurring in the torsion beam can be independently controlled separately from the torsion beam stiffness, and the maximum principal stress value can be effectively set and Torsion beam stiffness. The result is improved durability of the torsion beam for metal fatigue.

1‧‧‧Torque beam rear suspension

10‧‧‧Torque beam assembly

11L, 11R‧‧‧ front positioning arm

12, 42, 52, 62, 72, 82, 92‧‧‧ Torsion beams

13‧‧‧ Certain shape department

14a‧‧‧1st asymmetric shape

14b‧‧‧2nd asymmetric shape

15a‧‧‧1st connection

15b‧‧‧2nd connection

16L, 16R‧‧ ‧ spring bearing

17‧‧‧ recess

18a‧‧‧1st foot

18b‧‧‧2nd foot

19a‧‧‧Outer wall

19b‧‧‧Inside wall

20‧‧‧ Spring

30‧‧‧ damper

JL, JR‧‧ ‧ pivot

WL, WR‧‧‧ wheels

C1, C2‧‧‧ intersection

The middle face of the first foot of IPa‧‧

The middle face of IPb‧‧‧2nd foot

Thickness or width dimension of LF‧‧‧1st foot

LR‧‧‧The thickness or width of the second foot

L1, L2, L3‧‧‧ Straight line

P1, P2‧‧‧ front end point

P3, P4‧‧‧ vertex

OV‧‧‧ axis

P1, P2‧‧‧ compressive stress

Fig. 1 is a schematic perspective view of a torsion beam type suspension device as an example of a suspension device to which the present invention is applicable.

2 is a view showing a torsion beam combination provided with a torsion beam according to the present invention A schematic perspective view of an example of a piece.

Figure 3 is a schematic plan view of the torsion beam assembly of Figure 2.

Figure 4 is a schematic bottom view of the torsion beam assembly of Figure 2 taken along with the principal stresses occurring in the torsion beam.

Figure 5A is a schematic cross-sectional view of the torsion beam along arrow line A-A of Figure 2 .

Figure 5B is a schematic cross-sectional view of the torsion beam along arrow line B-B of Figure 2.

Figure 5C is a schematic cross-sectional view of the torsion beam along arrow line C-C of Figure 2.

Figure 5D is a schematic cross-sectional view of the torsion beam along arrow line D-D of Figure 2.

Fig. 6 is an enlarged view of a section (Fig. 5B) along the arrow line B-B of Fig. 2.

Fig. 7 is a schematic view showing a change in the cross section of the torsion beam according to the first embodiment.

Fig. 8A is a schematic cross-sectional view showing a perspective view of a torsion beam according to a second embodiment, and is a torsion beam taken along an arrow line A-A of Fig. 2;

Fig. 8B is a schematic cross-sectional view showing a perspective view of a torsion beam according to a second embodiment, and is a torsion beam taken along an arrow line B-B of Fig. 2;

Fig. 8C is a schematic cross-sectional view showing a torsion beam of the torsion beam according to the second embodiment, and is a torsion beam along the arrow line C-C of Fig. 2;

Fig. 8D is a schematic cross-sectional view showing a perspective view of a torsion beam according to a second embodiment, and is a torsion beam taken along an arrow line D-D of Fig. 2;

Fig. 9A is a schematic cross-sectional view showing a perspective view of a torsion beam according to a third embodiment, and is a torsion beam taken along an arrow line A-A of Fig. 2;

Fig. 9B is a schematic cross-sectional view showing a perspective view of a torsion beam according to a third embodiment, and is a torsion beam taken along an arrow line B-B of Fig. 2;

Figure 9C is a schematic cross-sectional view showing the torsion beam according to the third embodiment. Figure, and is a schematic cross-sectional view of the torsion beam along arrow line C-C of Figure 2.

Fig. 9D is a schematic cross-sectional view showing a torsion beam of the torsion beam according to the third embodiment, and is a torsion beam along the arrow line D-D of Fig. 2;

Fig. 10A is a schematic cross-sectional view showing a perspective view of a torsion beam according to a fourth embodiment, and is a torsion beam taken along an arrow line A-A of Fig. 2;

Fig. 10B is a schematic cross-sectional view showing a perspective view of a torsion beam according to a fourth embodiment, and is a torsion beam taken along an arrow line B-B of Fig. 2;

Fig. 10C is a schematic cross-sectional view showing a torsion beam of the torsion beam according to the fourth embodiment, and is a torsion beam along the arrow line C-C of Fig. 2;

Fig. 10D is a schematic cross-sectional view showing a torsion beam of the torsion beam according to the fourth embodiment, and is a torsion beam along the arrow line D-D of Fig. 2;

Fig. 11A is a schematic cross-sectional view showing a perspective view of a torsion beam according to a fifth embodiment, and is a torsion beam taken along an arrow line A-A of Fig. 2;

Fig. 11B is a schematic cross-sectional view showing a perspective view of a torsion beam according to a fifth embodiment, and is a torsion beam taken along an arrow line B-B of Fig. 2;

Fig. 11C is a schematic cross-sectional view showing a schematic cross section of the torsion beam according to the fifth embodiment, and is a torsion beam along the arrow line C-C of Fig. 2;

Fig. 11D is a schematic cross-sectional view showing a perspective view of a torsion beam according to a fifth embodiment, and is a torsion beam taken along an arrow line D-D of Fig. 2.

Fig. 12A is a schematic cross-sectional view showing a perspective view of a torsion beam according to a sixth embodiment, and is a torsion beam taken along an arrow line A-A of Fig. 2;

Fig. 12B is a schematic cross-sectional view showing a perspective view of a torsion beam according to a sixth embodiment, and is a torsion beam taken along an arrow line B-B of Fig. 2;

Figure 12C is a schematic cross-sectional view showing the torsion beam according to the sixth embodiment. The drawing is a schematic sectional view of the torsion beam along the arrow line C-C of Fig. 2.

Fig. 12D is a schematic cross-sectional view showing a perspective view of a torsion beam according to a sixth embodiment, and is a torsion beam taken along an arrow line D-D of Fig. 2;

Fig. 13A is a schematic cross-sectional view showing a perspective view of a torsion beam according to a seventh embodiment, and is a torsion beam taken along an arrow line A-A of Fig. 2;

Fig. 13B is a schematic cross-sectional view showing a perspective view of a torsion beam according to a seventh embodiment, and is a torsion beam taken along arrow line B-B of Fig. 2;

Fig. 13C is a schematic cross-sectional view showing a perspective view of a torsion beam according to a seventh embodiment, and is a torsion beam taken along an arrow line C-C of Fig. 2;

Fig. 13D is a schematic cross-sectional view showing a perspective view of a torsion beam according to a seventh embodiment, and is a torsion beam taken along an arrow line D-D of Fig. 2;

Form for implementing the invention

Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. Further, the symbols F and R shown on the drawing indicate the front and rear of the vehicle when the torsion beam is attached to the vehicle body.

First, a first embodiment of the present invention will be described with reference to Figs. 1 to 7 .

In FIG. 1, the torsion beam type rear suspension device 1 includes a torsion beam assembly 10, a spring 20 disposed between the torsion beam assembly 10 and the vehicle body, and a damper 30. As shown in FIG. 1 and FIG. 2, the torsion beam assembly 10 is provided with a pair of left and right arm members extending forward and backward in the vehicle front and rear direction, and positioning arms 11L and 11R. The torsion beam 12 of the front positioning arms 11L, 11R. The torsion beam assembly 10 further has: a support bomb A pair of left and right spring receiving portions 16L and 16R of the lower end portion of the spring 20; and a damper receiving portion (not shown) that supports the lower end portion of the damper 30. The base end portions of the front positioning arms 11L and 11R are coupled to the vehicle body so as to be swingable in the vertical direction or the vertical plane around the pivots JL and JR. The front end portions of the positioning arms 11L and 11R are rotatably attached to the front end portions of the positioning arms 11L and 11R on the side opposite to the base end portion.

The torsion beam 12 is composed of a hollow member extending between the front positioning arms 11L and 11R and extending in the left-right direction of the automobile, that is, in the width direction. The spring receiving portions 16L and 16R are formed on the opposite side of the pivot shafts JL and JR with respect to the torsion beam 12, and are the rear side of the automobile in the present embodiment, and are formed between the front positioning arms 11L and 11R and the torsion beam 12, A damper receiving portion (not shown) is provided in the vicinity of the spring receiving portions 16L, 16R among the front positioning arms 11L, 11R.

The torsion beam 12 according to the first embodiment includes a fixed shape portion 13 provided at approximately the center in the longitudinal direction thereof, and first and second connecting portions 15a provided at both end portions and coupled to the front positioning arms 11L and 11R. And 15b; and first and second asymmetrical shape portions 14a and 14b provided between the fixed shape portion 13 and the first and second connecting portions 15a and 15b. As shown in FIGS. 3, 4, and 5A to 5D, the torsion beam 12 has a first leg portion 18a disposed on the side closer to the pivots JL and JR when mounted on the vehicle body, and is disposed away from the pivot axis JL. The second leg portion 18b on the JR side has an approximately inverted V or U-shaped cross section. A recess 17 extending in the longitudinal direction of the torsion beam 12 is formed between the first and second leg portions 18a and 18b. The recess 17 is formed so that the first and second connecting portions 15a and 15b are directed toward the fixed shape portion 13 and the depth is gradually deepened by the first and second asymmetric shape portions 14a and 14b, and is formed in the fixed shape portion 13 The depth is roughly fixed.

The fixed shape portion 13 is a region in which the cross-sectional shape perpendicular to the longitudinal direction of the torsion beam 12 does not slightly change in the longitudinal direction of the torsion beam 12 .

The first and second connecting portions 15a and 15b have an appropriate shape to couple the torsion beam 12 to the front positioning arms 11L and 11R. Further, in the first and second connecting portions 15a and 15b, the shallow recess 17 is formed only in the region adjacent to the first and second asymmetric shaped portions 14a and 14b (Fig. 5D). In the present embodiment, the recess 17 is not formed at the front end of the torsion beam 12 coupled to the front positioning arms 11L, 11R and a portion adjacent to the front end. Alternatively, the recesses 17 may not be provided in the first and second connecting portions 15a and 15b. The first and second connecting portions 15a and 15b may be configured to have a region having a length approximately equal to a diameter corresponding to the first and second connecting portions 15a and 15b from the distal end of the torsion beam 12.

As shown in FIGS. 5A and 5B, the first and second asymmetrical shape portions 14a and 14b have the first and second asymmetrical shape portions such that the first leg portion 18a is thicker than the second leg portion 18b. The cross sections of 14a and 14b are formed in an asymmetrical region in the front-rear direction.

Here, when referring to the enlarged view of the cross section (Fig. 5B) along the arrow line BB of Fig. 2, that is, Fig. 6, the torsion beam 12 is composed of the outer wall portion 19a and the inner wall portion 19b, and is formed therebetween. Internal space. The outer wall portion 19a is a wall portion from the front end point P1 of the first leg portion 18a passing through the vertex P4 to the front end point P2 of the second leg portion 18b. The inner wall portion 19b passes from the vertex point P1 of the first leg portion 18a to the wall portion of the tip end point P2 of the second leg portion 18b through the vertex P3 of the recess portion 17. The axis OV is an axis that passes through the center between the front end points P1 and P2 of the first and second leg portions 18a and 18b perpendicularly to the line segment P1P2. Twisted according to the first embodiment In the force beam 12, the apex P4 of the outer wall portion 19a is disposed on the axis OV, but the apex P3 of the inner wall portion 19b is offset from the axis OV at the rear in the asymmetrical shape portions 14a, 14b, that is, with the pivot The direction in which JL and JR are separated.

Further, in Fig. 6, the straight line L1 is a common wire that is joined to the front end points P1 and P2 of the first and second leg portions 18a and 18b. The straight line L2 is a straight line parallel to the straight line L1 and joined to the apex P3 of the recess 17. The straight line L3 is a straight line parallel to the straight lines L1 and L2 and equidistant from the straight lines L1 and L2. Among the asymmetrically shaped portions 14a and 14b, among the portions where the first and second leg portions 18a and 18b intersect the straight line L3, the thickness or width dimension of the first leg portion 18a is made smaller than the thickness of the second leg portion 18b or The width is larger. The thickness or width dimension of the first leg portion 18a may be the outer wall portion 19a and the inner wall portion 18b passing through the intersection C1 between the intermediate surface IPa between the outer wall portion 19a and the inner wall portion 18b and the straight line L3 in the first leg portion 18a. The distance between LF. Similarly, the thickness or width dimension of the second leg portion 18b can be defined as the outer wall portion 19a and the inner wall passing through the intersection C2 of the intermediate surface IPb between the outer wall portion 19a and the inner wall portion 19b and the straight line L3 in the second leg portion 18b. The distance LR between the portions 18b.

In the first and second asymmetrical shape portions 14a and 14b, the ratio α=LF/LR of the thickness or the width dimension of the first and second leg portions 18a and 18b varies in the longitudinal direction of the torsion beam 12, but In the first embodiment, the maximum αmax is 1.8. The inventors of the present invention found the following facts from the numerical analysis of the torsion beam 12.

(1) When the value of α is larger, the tensile stress S1 occurring in the inner wall portion 19b where the recess 17 is formed in the first leg portion 18a is reduced.

(2) When the value of α is larger, it occurs in the second leg portion 18b in the formation of the recess 17 The tensile stress S2 of the wall portion 19b increases.

From the above reasons (1) and (2), it is understood that the ratio of the thickness or the width dimension of the first and second leg portions 18a and 18b in the first and second asymmetrical shape portions 14a and 14b is α. The value system has an appropriate range, and the numerical analysis system is preferably 1.1 ≦ α ≦ 2.5. Further, when the value of α is larger than necessary, the formability when the torsion beam 12 is press-formed from the metal pipe member is lowered. Further, from the numerical analysis, it is found that the dimensions of the first and second asymmetrical shape portions 14a and 14b in the longitudinal direction are equal to each other in order to achieve a sufficient stress relaxation effect, and 5% of the length of the torsion beam 12 The above is better. Further, the dimension of the first and second asymmetrical shape portions 14a and 14b in the longitudinal direction is preferably 40% or less of the length of the torsion beam 12. Further, in the first embodiment, the lengths of the first and second asymmetrical shape portions 14a and 14b are 20% of the length of the torsion beam 12.

Next, the action of the torsion beam 12 according to the first embodiment will be described with reference to Fig. 4 .

When one of the pair of right and left front positioning arms 11R and 11L swings around the pivots JR and JL, the other front positioning arm swings toward the opposite side. For example, when the right wheel mounted on the torsion beam type rear suspension device 1 receives an upward force, the right front positioning arm 11R swings upward with the pivot JR as the center, and the left front positioning arm 11L is The front positioning arm 11R on the right side relatively swings downward. As a result, as shown in FIG. 4, in the right half of the torsion beam 12, a large tensile stress S1 is generated in the inner wall portion 18b of the first leg portion 18a in the direction F1, and in the left half in the second leg portion. The inner wall portion 19b of 18b generates a tensile stress S2 smaller than S1 in the direction F2. On the contrary, in the right half of the torsion beam 12, a compressive stress P1 occurs in the inner wall portion 19b of the second leg portion 18b, in the left half. The compressive stress P2 is generated in the inner wall portion 18b of the first leg portion 18b. Further, in the case where the left wheel receives the upward force and the left front positioning arm 11L swings upward, it can be understood that the opposite effect is exerted.

According to the torsion beam 12 of the first embodiment, the first and second asymmetrical portions 14a and 14b of the torsion beam 12 can greatly reduce the stretching in the direction F1 of the inner wall portion 18b of the first leg portion 18b. Stress S1. This is because the first leg portion 18a is thickened in the first and second asymmetrical shape portions 14a and 14b of the torsion beam 12, that is, the distance LF between the outer wall portion 19a and the inner wall portion 18b is increased. In the asymmetric shape portions 14a and 14b, the cross-sectional rigidity of the first leg portion 18a is increased to reduce the tensile stress. On the other hand, among the first and second asymmetrical shape portions 14a and 14b of the torsion beam 12, the distance LR between the outer wall portion 19a and the inner wall portion 19b in the second leg portion 18b is larger than that of the first leg portion 18a. The distance LF between the outer wall portion 19a and the inner wall portion 18b is smaller, thus reducing the section rigidity. Therefore, in the first and second asymmetrical shape portions 14a and 14b of the torsion beam 12, the tensile stress S2 of the inner wall portion 19b of the second leg portion 18b is increased, but the asymmetric shape portion is formed. The α value in 14a and 14b is appropriately adjusted so that the tensile stress S2 can be made smaller than the tensile stress S1.

According to the torsion beam 12, the torsion beam 12 assembly 10, and the torsion beam type rear suspension device 1 of the first embodiment, the torsion beam 12 is provided with an interval LF between the outer wall portion 19a and the inner wall portion 19b in the vehicle front and rear direction. LR is the first and second asymmetrical shape portions 14a and 14b formed asymmetrically, so that the stress occurring in the torsion beam 12 can be independently controlled separately from the stiffness of the torsion beam 12, and the torsion beam 12 can be easily and appropriately set. The value of torsional stiffness and maximum principal stress.

Further, the torsion beam 12 according to the first embodiment is similar to the conventional torsion beam, and the outer wall portion 19a can be easily replaced with a conventional torsion beam type by forming a cross-sectional shape that is symmetrical with respect to the axis OV in the front-rear direction. Suspension device. According to the torsion beam 12 according to the present embodiment, the value of the maximum principal stress of the torsion beam 12 can be reduced while maintaining the desired suspension performance, and the metal fatigue occurring in the torsion beam 12 can be effectively reduced.

Next, a second embodiment of the present invention will be described with reference to Figs. 8A to 8D. In FIGS. 8A to 8D, the same components as those in the embodiment shown in FIGS. 5A to 5D are denoted by the same reference numerals.

Similarly to the torsion beam 12 according to the first embodiment, the torsion beam 42 of the second embodiment includes the fixed shape portion 13 (FIG. 8A), the asymmetric shape portions 14a and 14b (FIGS. 8B and 8C), and the connection. In the portions 15a and 15b (Fig. 8D), the first leg portions 18a are formed thicker than the second leg portions 18b in the asymmetric shape portions 14a and 14b. However, in the second embodiment, the apex P4 of the outer wall portion 19a is offset from the axis OV, that is, the direction separating from the pivots JL and JR, which is different from the first embodiment. The apex P3 of the inner wall portion 19b is also offset rearward from the axis OV.

According to the torsion beam 42 according to the second embodiment, since the position of the vertex P4 of the outer wall portion 19a is not limited to the axis OV, the fixed shape portion and the asymmetrical shape portion 14a, 14b can be more freely selected than in the first embodiment. Compared with the torsion beam 12 according to the first embodiment, the cross-sectional shape can further reduce the tensile stress while suppressing the torsional rigidity of the torsion beam 42.

Next, a third embodiment of the present invention will be described with reference to FIGS. 9A to 9D. form. In FIGS. 9A to 9D, the same components as those in the embodiment shown in FIGS. 5A to 5D are denoted by the same reference numerals.

Similarly to the torsion beam 12 according to the first embodiment, the torsion beam 52 of the third embodiment includes a constant shape portion 13 (FIG. 9A), asymmetrical shape portions 14a and 14b (FIGS. 9B and 9C), and a connection. In the portions 15a and 15b (Fig. 9D), the first leg portions 18a are formed thicker than the second leg portions 18b in the asymmetric shape portions 14a and 14b. However, in the third embodiment, the apex P4 of the outer wall portion 19a is disposed on the axis OV in the fixed shape portion 13, but the asymmetrical shape portions 14a and 14b and the connecting portions 15a and 15b are offset from the axis OV in the front. That is, the point in the direction in which the pivots JL and JR are close to each other is different from that in the first embodiment. Further, in the third embodiment, the apex P3 of the inner wall portion 19b is disposed on the axis OV in the fixed shape portion 13, but is offset from the axis OV in the asymmetric shape portions 14a, 14b and the connecting portions 15a, 15b. The point at the rear is also different from that of the first embodiment.

According to the torsion beam 52 according to the third embodiment, the cross-sectional shape of the inner wall portion 19b is changed within a small range as compared with the first embodiment, and the stress reduction equivalent to that of the first embodiment can be achieved. The point of sexual excellence is favorable.

Next, a fourth embodiment of the present invention will be described with reference to Figs. 10A to 10D. In FIGS. 10A to 10D, the same components as those in the embodiment shown in FIGS. 5A to 5D are denoted by the same reference numerals.

Similarly to the torsion beam 12 according to the first embodiment, the torsion beam 62 of the fourth embodiment includes the fixed shape portion 13 (FIG. 10A), the asymmetric shape portions 14a and 14b (FIGS. 10B and 10C), and the connection. In the portions 15a and 15b (Fig. 10D), the first leg portion 18a is formed to be smaller than the second leg portion in the asymmetric shape portions 14a and 14b. 18b is thicker. However, in the fourth embodiment, the apex P4 of the outer wall portion 19a is disposed on the axis OV in the fixed shape portion 13, but is offset from the axis OV in the front side in the asymmetric shape portions 14a and 14b and the connecting portions 15a and 15b. That is, the point in the direction in which the pivots JL and JR are close to each other is different from that in the first embodiment. Further, in the fourth embodiment, the apex P3 of the inner wall portion 19b covers the entire length of the recess 17 on the axis OV.

According to the torsion beam 62 according to the fourth embodiment, since the shape selection range of the outer wall portion 19a is widened, the α value can be increased in the asymmetric shape portions 14a and 14b as compared with the first embodiment, even if it is small. The same effect can be obtained also in the asymmetric shape portions 14a and 14b.

Next, a fifth embodiment of the present invention will be described with reference to Figs. 11A to 11D. In FIGS. 11A to 11D, the same components as those in the embodiment shown in FIGS. 5A to 5D are denoted by the same reference numerals.

Similarly to the torsion beam 12 according to the first embodiment, the torsion beam 72 of the fifth embodiment includes a constant shape portion 13 (FIG. 11A), asymmetrical shape portions 14a and 14b (FIGS. 11B and 11C), and a connection. In the portions 15a and 15b (Fig. 11D), the first leg portions 18a are formed thicker than the second leg portions 18b in the asymmetric shape portions 14a and 14b. However, in the fifth embodiment, the apexes P4 and P3 of both the outer wall portion 19a and the inner wall portion 19b are arranged on the axis OV, which is different from the first embodiment.

According to the torsion beam 72 according to the fifth embodiment, the α value in the asymmetric shape portions 14a and 14b can be increased, and the same effect as that of the asymmetric shape portions 14a and 14b can be obtained as compared with the first embodiment. At the same time, since the apexes P4 and P3 of the outer wall portion 19a and the inner wall portion 19b are all on the axis OV, Since it is located in the center of the width direction of the torsion beam 12, it is excellent in formability compared with the first embodiment.

Next, a sixth embodiment of the present invention will be described with reference to Figs. 12A to 12D. In FIGS. 12A to 12D, the same components as those in the embodiment shown in FIGS. 5A to 5D are denoted by the same reference numerals.

Similarly to the torsion beam 12 according to the first embodiment, the torsion beam 82 of the sixth embodiment includes the fixed shape portion 13 (FIG. 12A), the asymmetric shape portions 14a and 14b (FIGS. 12B and 12C), and the connection. In the portions 15a and 15b (Fig. 12D), the first leg portions 18a are formed thicker than the second leg portions 18b in the asymmetric shape portions 14a and 14b. However, in the sixth embodiment, the apexes P4 and P3 of both the outer wall portion 19a and the inner wall portion 19b are arranged on the axis OV, which is different from the first embodiment. Further, the recess 17 is formed in a symmetrical shape with respect to the axis OV in the front-rear direction of the automobile.

According to the torsion beam 82 according to the sixth embodiment, the α value in the asymmetric shape portions 14a and 14b can be increased, and the same effect as that of the asymmetric shape portions 14a and 14b can be obtained as compared with the first embodiment. Further, in the torsion beam 82 according to the sixth embodiment, since the apexes P4 and P3 of the outer wall portion 19a and the inner wall portion 19b are both on the axis OV of the torsion beam 82, the formability is better than that of the first embodiment. .

Next, a seventh embodiment of the present invention will be described with reference to Figs. 13A to 13D. In FIGS. 12A to 12D, the same components as those in the embodiment shown in FIGS. 5A to 5D are denoted by the same reference numerals.

Similarly to the torsion beam 12 according to the first embodiment, the torsion beam 92 of the seventh embodiment has a constant shape portion 13 (Fig. 13A) and an asymmetrical shape. The portions 14a and 14b (Figs. 13B and 13C) and the connecting portions 15a and 15b (Fig. 13D) have the first leg portions 18a formed thicker than the second leg portions 18b in the asymmetrically shaped portions 14a and 14b. In the seventh embodiment, the apexes P4 and P3 of both the outer wall portion 19a and the inner wall portion 19b are disposed on the axis OV, that is, at the center in the width direction of the torsion beam, and are different from the first embodiment. different. Further, the recess 17 is formed in a symmetrical shape with respect to the axis OV in the front-rear direction of the automobile.

According to the torsion beam 72 according to the seventh embodiment, the α value in the asymmetric shape portions 14a and 14b can be increased, and the same effect as that of the asymmetric shape portions 14a and 14b can be obtained as compared with the first embodiment. At the same time, since the tops of the outer wall portion 19a and the inner wall portion 19b are located at the center in the width direction of the torsion beam, the formability can be improved as compared with the first embodiment.

<Example>

Next, an embodiment of the present invention will be described.

Table 1 shows the simulation results using a torsion beam of approximately V-shape or U-shape forming a vertex above. Further, in Table 1, the simulation results of the respective examples are shown by using a ratio of a conventional torsion beam, that is, a comparative example. The approximate dimensions of the torsion beam used in the simulation were 1000 mm in the longitudinal direction, 95 mm in the longitudinal direction, and 55 mm in the longitudinal direction. Further, the simulation was performed by applying a reverse external force of 5000 N to the left and right wheels and shifting the height difference between the left and right wheels to 140 mm.

The torsion beam system as a comparative example does not have an asymmetrical shape portion, and the entire length of the torsion beam is symmetrically formed in the front-rear direction.

The first embodiment is a torsion beam according to the first embodiment, and the asymmetrically shaped portions 14a and 14b are extended across the longitudinal direction of the torsion beam. 200 mm, a torsion beam with an alpha value of 1.8 in the asymmetric shape portions 14a, 14b.

The second embodiment is a torsion beam according to the second embodiment, and the α value is 1.8 in the asymmetric shape portions 14a and 14b by extending the asymmetric shape portions 14a and 14b over one side in the longitudinal direction of the torsion beam by 400 mm. The torsion beam.

The third embodiment is a torsion beam according to the third embodiment, and the α value is 1.8 in the asymmetric shape portions 14a and 14b by extending the asymmetric shape portions 14a and 14b over a length of 200 mm on one side in the longitudinal direction of the torsion beam. The torsion beam.

The fourth embodiment is a torsion beam according to the fourth embodiment, and the α value is 1.8 in the asymmetric shape portions 14a and 14b by extending the asymmetric shape portions 14a and 14b over one side in the longitudinal direction of the torsion beam by 150 mm. The torsion beam.

The fifth embodiment is the torsion beam according to the fifth embodiment, and the α value is 1.8 in the asymmetric shape portions 14a and 14b by extending the asymmetric shape portions 14a and 14b over one side in the longitudinal direction of the torsion beam by 150 mm. The torsion beam.

The sixth embodiment is a torsion beam according to the sixth embodiment, and the α value is 1.8 in the asymmetric shape portions 14a and 14b by extending the asymmetric shape portions 14a and 14b over one side in the longitudinal direction of the torsion beam by 150 mm. The torsion beam.

The seventh embodiment is the torsion beam according to the seventh embodiment, and the α value is 1.8 in the asymmetric shape portions 14a and 14b by extending the asymmetric shape portions 14a and 14b over one side in the longitudinal direction of the torsion beam by 150 mm. Torque Liang.

In addition, in Table 1, the moldability is determined by the positional accuracy in the width direction and the height direction of the apex of the outer wall portion 19a and the inner wall portion 19b based on the FEM-based forming analysis result, and is set in the outer wall portion 19a and The case where the positional accuracy in the width direction and the height direction of the apex of the inner wall portion 19b exceeds 2 mm is Δ, and when it is more than 1 mm and is 2 mm or less, it is ○, and when it is 1 mm or less, it is ◎.

As can be understood from Table 1, in Example 2, the value of the maximum principal stress was reduced by 10%, and the torsional stiffness was approximately equal. Further, in the seventh embodiment, the formability is the same as that of the conventional torsion beam, and the value of the maximum principal stress is reduced by 6%, and the torsional rigidity is approximately equal. Since the fatigue durability of the torsion beam is about 1.5 times when the value of the maximum principal stress is reduced by 6%, and the fatigue durability of the torsion beam is about 2 times when the value of the maximum principal stress is reduced by 10%, according to the present invention, It can be understood that it is possible to obtain the torsional stiffness while maintaining one. Set, while improving the fatigue durability of the torsion beam.

The present invention is not limited to the embodiments described above, and various modifications and improvements can be made without departing from the spirit and scope of the invention.

For example, in the embodiment described above, the torsion beam 12, 42, 52, 62, 72, 82, 92 having an approximately V-shaped or approximately U-shaped apex formed at the upper side is opened for the lower opening, but is described. The configuration may be such that the opening is upward and the apex is formed on the lower side.

Further, in the embodiment described above, the asymmetric shape portions 14a and 14b are formed between the fixed shape portion 13 and the connecting portions 15a and 15b, and are gradually deformed from the fixed shape portion 13 toward the connecting portions 15a and 15b. Although the case will be described, the asymmetric shape portions 14a and 14b may be arbitrarily set at any position in the longitudinal direction of the torsion beam or in the deformation of the fixed shape portion 13 and the connecting portions 15a and 15b.

Further, the vertices of the cross sections orthogonal to the longitudinal directions of the torsion beams 12, 42, 52, 62, 72, 82, and 92 are disposed above and below, or how the vertices are displaced to the front and rear directions of the vehicle and Any direction in the up and down direction can be arbitrarily selected.

Further, in the embodiment described above, the case where the torsion beam type suspension device is the torsion beam type rear suspension device 1 will be described. However, the present invention can also be applied to, for example, the rear positioning arm type suspension device.

Industrial availability

Because it suppresses the fatigue of the metal of the torsion beam that constitutes the torsion beam suspension device, and improves the fatigue strength of the torsion beam suspension device, it is produced. Industry availability.

12‧‧‧Torque beam

14a, 14b‧‧‧Asymmetric shape

17‧‧‧ recess

18a‧‧‧1st foot

18b‧‧‧2nd foot

19a‧‧‧Outer wall

19b‧‧‧Inside wall

C1, C2‧‧‧ intersection

The middle face of the first foot of IPa‧‧

The middle face of IPb‧‧‧2nd foot

Thickness or width dimension of LF‧‧‧1st foot

LR‧‧‧The thickness or width of the second foot

L1, L2, L3‧‧‧ Straight line

P1, P2‧‧‧ front end point

P3, P4‧‧‧ vertex

OV‧‧‧ axis

Claims (18)

A torsion beam is a torsion beam for a vehicle suspension device having a pair of arm members, and the pair of arm members extend toward the front and rear direction of the vehicle, and is configured to be swingable in the up and down direction about a pivot center in one end. The wheel is coupled to the automobile body, and the wheel is rotatably mounted at an end portion on the opposite side of the end portion connected to the automobile body, and the torsion beam has a recess extending in the longitudinal direction, whereby the torsion beam system a first leg portion close to the pivot axis and a second leg portion remote from the pivot axis in a plane perpendicular to the longitudinal direction, and having a V-shaped or approximately U-shaped cross-sectional shape, the torsion beam having: a connecting portion at both ends of the torsion beam coupled to the arm member; a fixed shape portion provided at a central portion of the torsion beam in a longitudinal direction; and an asymmetrical shape portion disposed between the fixed shape portion and the connecting portion, In the fixed shape portion, the recess has a certain depth, and the first and second leg portions have approximately the same thickness or width dimension, and in the asymmetrical shape portion, Said recess depth is from the connecting portion toward the shaped portion becomes gradually deeper, and the first leg portion has a larger width dimension of the second leg than the width dimension. For example, the torsion beam of claim 1 of the patent scope, wherein before assembly When the suspension device for the torsion beam is attached to the vehicle body, the first leg portion is disposed closer to the pivot than the second leg portion. The torsion beam of claim 1, wherein each of the asymmetrical shape portions has a length of 5% or more and 40% or less of the length of the torsion beam. The torsion beam according to the first aspect of the invention, wherein the first leg portion has a width dimension of 1.1 times or more and 2.5 times or less the width dimension of the second leg portion. The torsion beam of claim 1, wherein each of the first and second leg portions has a distal end point, and the torsion beam is formed by forming a recess between the front end points of the first and second leg portions The inner wall portion and the outer wall portion other than the outer wall portion, wherein the apex of the outer wall portion is disposed in the asymmetric shape portion and disposed between the first and second leg portions The line passing through the front end point is perpendicular to the axis. The torsion beam of claim 5, wherein the apex of the inner wall portion is disposed in the asymmetrical shape portion and disposed on the axis. The torsion beam of claim 5, wherein the apex of the inner wall portion is in the asymmetrical shape portion, and is offset from the axis to the first leg portion side. The torsion beam according to claim 5, wherein the apex of the inner wall portion is in the asymmetrical shape portion, and is offset from the axis to the second leg portion side. For example, the torsion beam of the first application of the patent scope, wherein the first and second Each of the leg portions has a distal end point, and the torsion beam is formed by forming an inner wall portion of the recess between the distal end points of the first and second leg portions, and an outer wall portion other than the outer wall portion. The apex of the outer wall portion is in the asymmetrical shape portion, and is offset from the first leg portion in the middle of the front end point of the first and second leg portions and is perpendicular to an axis passing through the straight line at the front end point. side. The torsion beam of claim 9, wherein the apex of the inner wall portion is disposed in the asymmetrical shape portion and disposed on the axis. The torsion beam according to claim 9, wherein the apex of the inner wall portion is in the asymmetrical shape portion, and is offset from the axis to the first leg portion side. The torsion beam of claim 9, wherein the apex of the inner wall portion is in the asymmetrical shape portion, and is offset from the axis to the second leg portion side. The torsion beam of claim 1, wherein each of the first and second leg portions has a distal end point, and the torsion beam is formed by forming a recess between the front end points of the first and second leg portions The inner wall portion and the outer wall portion other than the outer wall portion, wherein the apex of the outer wall portion is in the asymmetrical shape portion from the middle of the first and second leg portions The axis perpendicular to the straight line passing through the front end point is offset on the second leg side. The torsion beam of claim 13, wherein the apex of the inner wall portion is disposed in the asymmetrical shape portion and disposed on the axis. The torsion beam of claim 13, wherein the inner wall portion The apex is offset from the axis to the first leg side in the asymmetrical shape portion. The torsion beam of claim 13, wherein the apex of the inner wall portion is in the asymmetrical shape portion, and is offset from the axis to the second leg portion side. A torsion beam assembly comprising: a pair of arm members extending in a front-rear direction of the vehicle, and configured to be pivotally coupled to the vehicle body in a vertical direction about a pivot axis at one end, and in the foregoing The end portion of the opposite side of the end portion of the automobile body is rotatably mounted to the wheel; and the torsion beam according to any one of claims 1 to 16. A torsion beam type suspension device comprising: a pair of arm members extending in a front-rear direction of a vehicle, and configured to be coupled to the automobile body in a vertical direction about a pivot axis at one end thereof, and a wheel is rotatably mounted at an end portion of the opposite side of the end portion to which the automobile body is coupled; a coil spring is disposed between the vehicle body and the arm member; and a damper is disposed on the vehicle body and the arm Between the members; and the torsion beam described in any one of claims 1 to 17.