JP2000094917A - Torsion beam type suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of the part adjacent to both ends of a torsion beam by constituting the vehicle longitudinal width of a lower flat part so as to be maximum in the center and gradually reduced toward both ends of the area. SOLUTION: The U-shaped section of a torsion beam 12 is set to a form opened to the rear end of a trailing arm from the front end thereof, or backward. The depth of the U-shaped section is constant in the center of the torsion beam 12, and gradually increased toward both ends of the torsion beam 12. Since a hole 40 and an elliptic hole 42 are provided on a front edge 12A situated adjacently to a position 12H, this part is most easily deformed when a lateral force acts on a wheel. An area 12E in which the vehicle longitudinal width W1 of the lower flat part is larger than the vehicle longitudinal width Wu of the upper flat part includes the position 12H, which is the part most easily deformed when the lateral force acts thereon, and the vicinity thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a suspension for a vehicle such as an automobile, and more particularly to a torsion beam type suspension.

[0002]

2. Description of the Related Art A torsion beam type suspension is
Generally, a pair of trailing arms spaced apart from each other in the lateral direction of the vehicle and pivotally supported by the vehicle body at the front end and rotatably supporting the wheels at the rear end, and extending in the lateral direction of the vehicle by welding at both ends. A torsion beam connected to a pair of trailing arms, and when the left and right wheels bounce and rebound in opposite phases, the left and right trailing arms pivot up and down in opposite directions around the front end, As a result, the torsion beam is elastically twisted by the trailing arm, thereby generating a force that suppresses wheel bounce and rebound.

As one of such torsion beam type suspensions, as described in, for example, Japanese Utility Model Application Laid-Open No. 58-90814, a torsion beam substantially comprises a U-shaped curved portion, an upper flat portion, and a lower flat portion. A torsion beam type suspension having a U-shaped cross section opened rearward and having a lower plane portion having a width in the vehicle longitudinal direction set to be larger than the width of the upper plane portion in the vehicle longitudinal direction over the entire length of the torsion beam is already known. I have.

According to the torsion beam type suspension described in the above publication, the strength of the lower flat portion of the torsion beam which receives a tensile stress when a downward load is applied to the vehicle is improved. The durability of the torsion beam can be improved as compared with the case where the width of the portion in the vehicle front-rear direction is the same.

[0005]

In a general torsion beam type suspension, when a large lateral force acts on the wheel, for example, when the wheel collides with a curb, the most deformable portions are located at both ends of the torsion beam. It is an adjacent part. However, in the torsion beam type suspension described in the above publication, the torsion beam has a constant cross-sectional shape over its entire length, so that there is a problem that the weight efficiency is low in terms of improving the strength against the lateral force of the wheel. Since the shear center of the cross section is low, there is a problem that the roll steer of the vehicle tends to oversteer.

The present invention is directed to a conventional torsion beam type suspension in which the width of the lower plane portion of the torsion beam having a U-shaped cross section in the vehicle longitudinal direction is set to be larger than the width of the upper plane portion in the vehicle longitudinal direction. SUMMARY OF THE INVENTION It is an object of the present invention to improve the strength only at a necessary portion of a torsion beam, thereby improving the weight efficiency with respect to the strength improvement against the lateral force of a wheel and the roll of a vehicle. The purpose is to reduce oversteering of the steering.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided a vehicle having a vehicle, which is spaced apart from each other in a lateral direction of a vehicle, pivotally supported by a vehicle body at a front end, and rotatably supports a wheel at a rear end. A torsion beam having a pair of trailing arms and a torsion beam extending laterally of the vehicle and integrally connecting the trailing arms, wherein the torsion beam has a U-shaped curved portion, an upper flat portion, and a lower side. U which is substantially open in the front-rear direction of the vehicle and has a flat portion
2. A torsion beam type suspension according to claim 1, wherein said lower flat portion has a width in the front-rear direction of the vehicle larger than said upper flat portion in a region near both ends of said torsion beam. Or a pair of trailing arms spaced apart from each other in the lateral direction of the vehicle and pivotally supported by the vehicle body at the front end and rotatably supporting the wheels at the rear end, and the trailing arms extending in the lateral direction of the vehicle. And a torsion beam suspension having a torsion beam integrally connecting the torsion beam, wherein the torsion beam has a U-shaped cross section substantially opened in the vehicle front-rear direction.
As for the length of the torsion beam extending in the direction perpendicular to the longitudinal direction, the side below the bottom of the U-shaped cross section is larger than the side above the bottom in the region near both ends of the torsion beam. A torsion beam type suspension having an extension length.
Or a pair of trailing arms spaced apart from each other in the lateral direction of the vehicle and pivotally supported by the vehicle body at the front end and rotatably supporting the wheels at the rear end, and the tray extending in the lateral direction of the vehicle. In a torsion beam type suspension having a torsion beam integrally connecting a ring arm, the torsion beam includes a U-shaped curved portion, an upper flat portion, and a lower flat portion, which are substantially opened in a vehicle longitudinal direction.
A torsion beam, wherein the lower plane portion has a width in the vehicle front-rear direction larger than that of the upper plane portion in a region where a change in a section coefficient of the torsion beam is larger than another portion. This is achieved by a suspension of the type (claim 5).

According to the first aspect of the present invention, the torsion beam has a U-shaped cross section substantially opened in the front-rear direction of the vehicle, comprising a U-shaped curved portion, an upper flat portion, and a lower flat portion. The portion has a width in the vehicle front-rear direction larger than the upper flat portion in a region near both ends of the torsion beam, and according to the configuration of claim 4, the torsion beam is substantially U-shaped open in the vehicle front-rear direction. U which has a cross-section and extends in a direction perpendicular to the longitudinal direction of the torsion beam.
Since the side below the bottom of the shaped cross section has a larger extension length in the area near both ends of the torsion beam than the side above the bottom, the part that is most likely to deform when a lateral force acts on the wheel The strength of the portion adjacent to both ends of the torsion beam is effectively improved.

Similarly, according to the configuration of the fifth aspect, the torsion beam has a U-shaped cross section substantially opened in the front-rear direction of the vehicle, comprising a U-shaped curved portion, an upper flat portion, and a lower flat portion. The lower flat portion has a larger width in the vehicle front-rear direction than the upper flat portion in a region where the change in the section coefficient of the torsion beam is larger than the other portions, so that it is most easily deformed when a lateral force acts on the wheel. The strength of the area is effectively improved.

According to the first, fourth, or fifth aspect of the present invention, since the shear center of the area other than the predetermined area of the torsion beam does not become low, the lower flat portion is larger than the upper flat portion over the entire length of the torsion beam. Compared to a structure having a width in the front-rear direction of the vehicle or a structure in which a side portion below the bottom of the U-shaped cross section has a larger extension length than a side portion above the bottom over the entire length of the torsion beam, Oversteer of the roll steer is reduced.

According to the present invention, in order to effectively achieve the above-mentioned main object, in the structure of the first aspect, the depth of the U-shaped cross section at both ends of the torsion beam is set to both ends of the torsion beam. And the region is configured to include a boundary between a portion where the depth of the U-shaped cross section is constant and a portion where the depth of the U-shaped cross section is gradually increased. Configuration of item 2).

According to the structure of the second aspect, the depth of the U-shaped cross section at both ends of the torsion beam gradually increases toward both ends of the torsion beam, and the region has a portion where the depth of the U-shaped cross section is constant. And a portion where the depth of the U-shaped section gradually increases, so that one of the parts most easily deformed when a lateral force acts on the wheel without lowering the shear center in other areas. One of the boundaries is reliably strengthened.

According to the present invention, in order to effectively achieve the above-mentioned main object, in the configuration of claim 1, the torsion beam has a notch at the bottom of the U-shaped cross section near both ends, The region is configured to include a portion provided with the notch (the configuration according to claim 3).

According to the third aspect of the present invention, the torsion beam has a notch at the bottom of the U-shaped cross section near both ends, and the region includes a portion provided with the notch. Without lowering, the notch part, which is one of the parts most likely to be deformed when a lateral force acts on the wheel, is surely strengthened.

[0015]

According to a preferred aspect of the present invention, in the configuration of the first aspect, the width of the lower flat portion in the vehicle longitudinal direction is substantially at the center of the region. It is configured to be the largest and to gradually decrease toward both ends of the region (preferred embodiment 1).

According to another preferred embodiment of the present invention, in the configuration of the third aspect, the depth of the U-shaped cross section at both ends of the torsion beam gradually increases toward both ends of the torsion beam, The notch is configured to be located at or near a boundary between a portion where the depth of the U-shaped cross section is constant and a portion where the depth of the U-shaped cross section is gradually increased (preferred embodiment). 2).

According to another preferred embodiment of the present invention, in the configuration of the above-described preferred embodiment 2, the region is configured to include the boundary and the portion provided with the notch (preferred embodiment 3). ).

According to another preferred aspect of the present invention, in the configuration of the first aspect, the region includes a portion that is most easily deformed when a lateral force acts on the wheel ( Preferred embodiment 4).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned claim 4, the extension length of the side portion below the bottom of the U-shaped section is substantially at the center of the region. In this case, it is configured to be largest and to gradually decrease toward both ends of the region (preferred embodiment 5).

According to another preferred embodiment of the present invention, in the configuration of the fourth aspect, the region is configured to include a portion which is most easily deformed when a lateral force acts on the wheel ( Preferred embodiment 6).

In the present specification, the "region most susceptible to deformation" is defined as having a maximum elastic deformation when a lateral force acts on a wheel in a structure in which the features of the present invention are not incorporated. Means part.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1A and 1B are a plan view and a rear view, respectively, showing one embodiment of a torsion beam type suspension according to the present invention. FIGS. FIG. 3 is an enlarged partial plan view, an enlarged partial rear view, and an enlarged partial side view showing a portion.

In these figures, 10L and 10R denote left and right trailing arms, respectively, which are spaced apart from each other in the lateral direction of the vehicle, and 12 denotes a torsion beam extending in the lateral direction of the vehicle. The trailing arms 10L and 10R are formed of a substantially S-shaped steel tubular member, and the torsion beam 12 has a substantially U-shaped cross section.
It is formed from a shaped steel plate. The trailing arms 10L and 10R are provided with spring seat members 14 at positions rearward of the torsion beam 12 inside the vehicle.
L and 14R are fixed by welding.

The trailing arms 10L and 10R are integrally fixed to the front end, and are pivotally supported on a vehicle body (not shown) by rubber bush devices 18L and 18R having axes 16L and 16R. At the rear end of the trailing arms 10L and 10R, a bracket 20 as a wheel carrier is fixed, and the bracket 20 rotatably around a rotation axis 22 supports a wheel (not shown). ing.

In the illustrated embodiment, the U-shaped section of the torsion beam 12 is set so as to open from the front end of the trailing arm toward the rear end, that is, backward. The depth of the U-shaped cross section is constant at the center of the torsion beam 12 and gradually increases toward both ends at both ends of the torsion beam 12, so that the curved leading edge 12A of the torsion beam 12 has both ends. It is gradually displaced forward toward.

Both ends of the torsion beam 12 are connected to the trailing arms 10L and 10R by welding portions 24 at the edges thereof.
Are connected integrally. In particular, in the illustrated embodiment, as shown in FIG.
The rear portions at both ends of the vehicle are rearward and outwardly protruding portions 12.
B, the center of both ends of the torsion beam 12 in the vehicle front-rear direction extends in the vehicle front-rear direction, and the outer edge between the center of both ends in the vehicle front-rear direction and the portion 12B has a substantially arc shape.

Also, in the illustrated embodiment, the torsion beam 12 is in the form of an "H" projecting slightly upward and is located inside the U-shaped cross section of the torsion beam 12 and trailing at both ends. Arms 10L and 1
The torsion bar 26 fixed to 0R also has the shape of an "" which projects slightly upward corresponding to the torsion beam.

FIGS. 5 to 7 are a partial plan view, a partial rear view, and an enlarged right half of the torsion beam 12, respectively.
FIG. 8 is a partial bottom view, and FIGS. 8A to 8D are enlarged cross-sectional views taken along lines AA, BB, CC, and DD in FIG. 5, respectively.

As can be seen from these figures, the U-shaped cross section of the torsion beam 12 comprises a U-shaped curved portion 28, an upper flat portion 30, and a lower flat portion 32. The front edge 12A of the U-shaped curved portion 28 is located above the vertical center plane 34 at the center of the torsion beam 12 in the left-right direction,
It gradually decreases toward both ends of the torsion beam 12, and is located substantially at the center plane 34 in the vertical direction at both ends of the torsion beam 12.

The width W of the upper flat portion 30 in the longitudinal direction of the vehicle.
u is constant over the entire length of the torsion beam 12, so that the ridgeline 36 between the U-shaped curved portion 28 and the upper flat portion 30 extends linearly in the left-right direction when viewed from above the vehicle. On the other hand, the width W of the lower flat portion 32 in the vehicle longitudinal direction is
l is constant at the center of the torsion beam 12 and is substantially the same as the width Wu, but between the position 12D in the middle of the region 12C where the depth of the U-shaped section is constant and both ends of the torsion beam 12. In the area 12E between them, it gradually changes.

In particular, in the illustrated embodiment, the width Wl of the lower flat portion 32 in the vehicle front-rear direction is the boundary portion 12G between the region 12C and the region 12F in which the depth of the U-shaped section gradually increases.
At the position 12H on both ends, and the position 1
The position gradually decreases toward the position 12D and both ends from 2H, and the position 12H is located at the center between the position 12D and both ends of the torsion beam. Therefore, the ridge 38 between the U-shaped curved portion 28 and the lower flat portion 32 when viewed from above and below the vehicle extends linearly in the left-right direction at the center of the torsion beam 12. However, in the region 12E, it extends like a hypotenuse of a triangle having a vertex at a position 12H.

The front edge 12A of the region 12F where the depth of the U-shaped section gradually increases near the position 12H is provided with a hole 40 and a long hole 42 as a notch. It extends obliquely to the horizontal direction along the front edge 12A. As described above, the depth of the U-shaped cross section of the torsion beam 12 gradually increases in the region 12F, and the hole 40 and the long hole 42 are provided in the front edge 12A near the position 12H. The position 12H and the part in the vicinity thereof are parts where the section modulus of the U-shaped cross section of the torsion beam 12 changes more than in other areas, in other words, the part that is most easily deformed when a lateral force acts on the wheel.

The bracket 20 fixed to the rear ends of the trailing arms 10L and 10R has a wheel support wall 44A extending in the vehicle front-rear direction and an integral part of the wall 44A and substantially in the inboard direction of the vehicle. Front wall portion 44 extending to
B and a rear wall portion 44C, a substantially "U" -shaped member, and an outer edge and a front wall portion 4 of an inclined wall portion 44D integrally formed with the wheel supporting wall portion 44A and extending downward and inward.
4B, it is integrally fixed to the corresponding trailing arm by welding at the lower edge of the rear wall portion 44C.

In particular, in the illustrated embodiment, the rear side wall portion 44C is located at a portion of the rear end of the trailing arm which extends substantially in the vehicle front-rear direction, whereas the front side wall portion 4C is located at the rear end portion.
4B is located at a position where the trailing arm begins to curve in the inboard direction of the vehicle when viewed from the rear end toward the front end. The outboard side portion of the front side wall portion 44B extends in the lateral direction of the vehicle, while the inboard side portion extends obliquely rearward of the vehicle as viewed from above the vehicle.

Further, in the illustrated embodiment, a pin 46 for fixing a lower end of a shock absorber (not shown) is fixed to the rear end of each trailing arm. As shown in FIG. 9, the pin 46 includes a central large-diameter portion 46A, a stepped small-diameter portion 46B on the outboard side from the large-diameter portion 46A, and a small-diameter portion 46C on the inboard side from the large-diameter portion 46A. A male screw portion 46D is provided at the tip of the small diameter portion 46C.

The pin 46 is inserted into holes provided in the inboard side wall 48 and the outboard side wall 50 at the trailing end of the trailing arm.
8 and is fixed to the rear end of the trailing arm by welding the outer end of the small diameter portion 46B to the wall portion 50. In particular, in the illustrated embodiment, the inner end of the pin 46 is located below its outer end, such that the axis 52 of the pin 46 extends at an angle to the horizontal. FIG. 3
9, an alternate long and short dash line 54 indicates an axis of the shock absorber (not shown) extending perpendicular to the axis 52.

According to the embodiment configured as described above,
The torsion beam 12 has a U-shaped curved portion 28 and an upper flat portion 3.
A region 12E having a U-shaped cross section composed of the lower flat portion 32 and the lower flat portion 32, in which the width Wl of the lower flat portion 32 in the front-rear direction of the vehicle is larger than the width Wu of the upper flat portion 30 in the front-rear direction, is a torsion beam 12 Since the area includes a region where the section modulus of the U-shaped cross section of the U-shaped cross section changes more greatly than other regions, in other words, a position 12H which is the most easily deformed when a lateral force acts on the wheel and a region in the vicinity thereof, Compared with the case where the width Wl is the same as the width Wu over the entire length of the torsion beam 12, the strength of the portion which is most easily deformed when a lateral force acts on the wheel can be surely improved.

According to the illustrated embodiment, the width Wl is the largest at the position 12H, and is larger than the position 12H.
Since the width decreases gradually toward D and both ends, the degree of lowering of the shear center of the U-shaped cross section of the torsion beam is reduced as compared with the case where the width Wl is larger than the width Wu over the entire length of the torsion beam 12. Thus, oversteering of the roll steer of the vehicle can be reduced.

Further, according to the illustrated embodiment, the depth of the U-shaped cross section of the torsion beam 12 gradually increases in the region 12F as described above, and the front edge 12A at a position close to the position 12H is notched. Hole 40 and slot 42 as a chip
The portion which is most likely to be deformed when a lateral force acts on the wheel is surely located at the position 12H and the vicinity thereof. Therefore, the portion for improving the strength by setting the width Wl as described above is provided. Can be surely made the most easily deformed portion.

In general, in a torsion beam type suspension in which the torsion beam has a U-shaped cross section,
When the torsion beam is twisted by the left and right wheels bouncing and rebounding in opposite phases, the highest stress acts on the open ends of the U-shaped cross section at both ends of the torsion beam. According to the illustrated embodiment, the rear portion at both ends of the torsion beam 12 has a portion 12B protruding rearward and outward of the vehicle, and the welded portion 24 is also provided at the outer edge of the portion 12B. As compared with the case where the structure is not provided, the stress acting on the rear portions at both ends of the torsion beam 12 can be reliably carried, thereby improving the durability of the suspension.

As shown in FIG. 3, the bracket 20 as a wheel carrier receives a lateral force Fy and a moment M in addition to the longitudinal force from the wheels as the vehicle travels. The lower weld edge of the 44C is subjected to a force that causes them to separate, the greatest force being at the inboard end of the weld. Therefore, in order to ensure the durability of the bracket, measures for increasing the length of the front and rear wall portions and reducing the rigidity of the bracket have been conventionally taken. However, in the former countermeasure, the welded portion becomes longer, so that an increase in cost is unavoidable, and in the latter countermeasure, a decrease in the rigidity of the suspension is inevitable.

According to the illustrated embodiment, the bracket 20
Of the front side wall portion 44B extends in the lateral direction of the vehicle, and the inboard side portion of the front wall portion 44B extends obliquely to the rear of the vehicle as viewed from above the vehicle.
When the lateral force Fy and the moment M act on the front side wall 4
A force is applied to the welded portion at the lower edge of 4B to separate it, and a force is applied to the portion on the outboard side to deform it in the lateral direction of the vehicle.

Therefore, in comparison with the conventional structure in which the front wall portion 44B extends in the lateral direction of the vehicle as in the conventional structure, the inboard side end of the welded portion at the lower edge of the front wall portion 44B is provided. This reduces the force acting on the bracket, thereby improving the durability of the bracket. It is not necessary to increase the length of the front and rear walls and to reduce the rigidity of the bracket. Thus, it is possible to avoid an increase in cost and a decrease in rigidity of the suspension.

In the illustrated embodiment, the front side wall 4
Although only the portion on the inboard side of 4B is inclined rearward of the vehicle, the portion on the inboard side of the rear wall portion 44C may be inclined, and the inboard side of both the front wall portion 44B and the rear wall portion 44C. May be inclined. In particular, in the latter case, it is preferable that the inboard-side portions of the front wall portion 44B and the rear wall portion 44C are inclined in opposite directions.

Further, according to the illustrated embodiment, the pin 46 for attaching the lower end of the shock absorber is provided with the large diameter portion 4.
It has a stepped small diameter portion 46B on the outboard side from 6A. In the case of the conventional structure (pin 46 ') shown in FIG. 10 in which the small-diameter portion has one tapered shape, the small-diameter portion of the pin material formed by forging is cut to form the tapered portion 46.
While E must be formed, according to the pin structure of the illustrated embodiment, the pin can be formed only by forging, and the pin can be manufactured at low cost.

Since the small-diameter portion 46B of the pin 46 has a shoulder between the steps, the positioning of the pin with respect to the trailing end of the trailing arm, which is performed using a jig, can be performed with ease using the shoulder. This makes it possible to mount the pins more efficiently than in the past.

The bracket 20 in the illustrated embodiment
And the structure of the pin 46 may be applied to a torsion beam type suspension having no structure of the torsion beam 12 of the present invention, and in this case, the above-described effects can be obtained.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments may be included within the scope of the present invention. It will be clear to those skilled in the art that is possible.

For example, in the above-described embodiment, the torsion beam 12 has a U-shaped cross section including the U-shaped curved portion 28, the upper flat portion 30, and the lower flat portion 32, but in the longitudinal direction of the torsion beam. The U-shape of the torsion beam as long as the side below the bottom of the U-shaped cross section in the vertical direction has a larger extension length than the side above the bottom in a predetermined region when viewed in the vertical direction. The cross-sectional shape may be a shape such as a parabola or a semi-ellipse having no distinct upper and lower plane portions, as shown in FIG. 11 corresponding to FIG. 8, for example. In FIG. 11, parts corresponding to the parts shown in FIG. 8 are denoted by the same reference numerals as in FIG.

In the above-described embodiment, the width Wl of the lower flat portion 32 in the vehicle front-rear direction gradually changes in the region 12E, and the width Wl between the U-shaped curved portion 28 and the lower flat portion 32 is changed. The ridge line 38 extends like the hypotenuse of a triangle having a vertex at the position 12H, but as long as the width Wl at the position 12H is maximum, the ridge line 38 is shown, for example, in FIG. 12 corresponding to FIG. It may extend in a curved manner as described above. In FIG. 12 as well, portions corresponding to those shown in FIG.
Are given the same reference numerals as in FIG.

In the above-described embodiment, the trailing arms 10L and 10R are substantially S-shaped, but the trailing arm may be of any form. Torsion beam 1 in
Although the U-shaped cross section of No. 2 is set to have a shape that opens backward, the opening direction of the U-shaped cross section may be set to a direction other than the backward direction.

Further, in the above embodiment, gussets are not provided at both ends of the torsion beam 12, but
The structure of the present invention may be applied to a suspension provided with gussets at both ends of the torsion beam, in which case the predetermined region preferably includes the position of the inner end of the gusset.

[0054]

As is apparent from the above description, according to the first or fourth or fifth aspect of the present invention, the two ends of the torsion beam, which are the parts which are most likely to be deformed when a lateral force acts on the wheel, are provided. It is possible to effectively improve the strength of an adjacent portion or a region where the change of the section coefficient of the torsion beam is larger than that of the other portion, and to increase the weight efficiency with respect to the improvement of the strength of the torsion beam as compared with the related art.

According to the first, fourth, or fifth aspect of the present invention, since the shear center of the region other than the predetermined region of the torsion beam does not become lower, the lower flat portion is larger than the upper flat portion over the entire length of the torsion beam. Compared to a structure having a width in the front-rear direction or a structure in which the side below the bottom of the U-shaped cross section has a longer extending length than the side above the bottom over the entire length of the torsion beam, Oversteer of the roll steer can be reliably reduced.

According to the second or third aspect of the present invention, the boundary portion is one of the most easily deformed portions when the lateral force acts on the wheel without lowering the shear center in the other region of the torsion beam. Alternatively, the notched portion can be reliably reinforced.

[Brief description of the drawings]

1A and 1B are a plan view and a rear view, respectively, showing one embodiment of a torsion beam type suspension according to the present invention.

FIG. 2 is an enlarged partial plan view showing a part of a right trailing arm and a torsion beam.

FIG. 3 is an enlarged partial rear view showing a part of a right trailing arm and a torsion beam.

FIG. 4 is an enlarged partial side view showing a part of a right trailing arm and a torsion beam.

FIG. 5 is a partial plan view showing a right half of the torsion beam in an enlarged manner.

FIG. 6 is a partial rear view showing a right half of the torsion beam in an enlarged manner.

FIG. 7 is an enlarged partial bottom view showing the right half of the torsion beam.

FIGS. 8A to 8D are enlarged cross-sectional views taken along lines AA, BB, CC, and DD in FIG. 5, respectively.

FIG. 9 is a front view showing a pin for attaching a lower end of the shock absorber in the illustrated embodiment.

FIG. 10 is a front view showing a conventional pin.

FIG. 11 is a partial plan view similar to FIG. 5, showing a right half of a torsion beam in a modified example in an enlarged manner.

12 (A) to 12 (D) each show a line AA, a line BB, and a line C-C of FIG.
C is an enlarged sectional view of a position along line DD. FIG.

[Explanation of symbols]

 10L, 10R ... Trailing arm 12 ... Torsion beam 20 ... Bracket 26 ... Torsion bar 26 28 ... U-shaped curved part 30 ... Upper flat part 32 ... Lower flat part 40 ... Hole 42 ... Elongated hole

Claims (5)

[Claims] 1. A pair of trailing arms spaced apart from each other in a lateral direction of a vehicle and pivotally supported by a vehicle body at a front end thereof and rotatably supporting wheels at a rear end thereof; In a torsion beam type suspension having a torsion beam integrally connecting a ring arm,
The torsion beam has a U-shaped cross section substantially opened in the front-rear direction of the vehicle including a U-shaped curved portion, an upper flat portion, and a lower flat portion, and the lower flat portion is formed in a region near both ends of the torsion beam. A torsion beam suspension having a width in the vehicle front-rear direction larger than the upper flat portion. 2. The depth of the U-shaped section at both ends of the torsion beam gradually increases toward both ends of the torsion beam, and the region includes a portion where the depth of the U-shaped section is constant and the U-shaped section. The torsion beam type suspension according to claim 1, further comprising a boundary portion with a portion where the depth of the cross section gradually increases. 3. The method according to claim 1, wherein the torsion beam is provided near the both ends.
2. A notch at a bottom of the cross section, wherein the region includes a portion where the notch is provided.
The torsion beam type suspension according to 1. 4. A pair of trailing arms spaced apart from each other in the lateral direction of the vehicle and pivotally supported by the vehicle body at the front end and rotatably supporting wheels at the rear end, and the tray extends in the lateral direction of the vehicle. In a torsion beam type suspension having a torsion beam integrally connecting a ring arm,
The torsion beam has a U-shaped cross-section substantially opened in the vehicle front-rear direction, and a side portion below a bottom of the U-shaped cross-section when viewed in terms of an extension length in a direction perpendicular to a longitudinal direction of the torsion beam is the same as the above. A torsion beam suspension having a longer extension length in a region near both ends of the torsion beam than a side portion above the bottom portion. 5. A pair of trailing arms spaced apart from each other in the lateral direction of the vehicle and pivotally supported by the vehicle body at the front end and rotatably supporting wheels at the rear end, and the tray extends in the lateral direction of the vehicle. In a torsion beam type suspension having a torsion beam integrally connecting a ring arm,
The torsion beam has a U-shaped cross section substantially opened in the vehicle front-rear direction, which includes a U-shaped curved portion, an upper flat portion, and a lower flat portion, and the lower flat portion has another variation in the cross-sectional coefficient of the torsion beam. A torsion beam type suspension having a width in the vehicle front-rear direction larger than the upper flat portion in a region larger than the portion.