Torsion bar unit

Abstract

To fix a torsion bar securely without processing an FRP at an end of the torsion bar using the FRP.SOLUTION: A torsion bar unit according to an embodiment of the invention includes: a cylindrical torsion bar formed of a fiber composite material; a first holding member having a first groove part for holding an end of the torsion bar; and a second holding member which has a second groove part for holding the end of the torsion bar at a position facing the first groove part and sandwiches and holds the end of the torsion bar with the first groove part and the second groove part by the first holding member overlapping therewith.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One embodiment of the present invention relates to a torsion bar unit.

Background Art

[0002] Conventionally, a torsion bar type suspension has been used as a vehicle suspension. The torsion bar type suspension includes an arm mechanism that supports a wheel and is rotatably connected to a vehicle body, and a torsion bar spring (hereinafter abbreviated as a torsion bar) that is connected between the arm mechanism and the vehicle body and is torsionally deformed according to the swing of the arm mechanism.

[0003] When connecting the torsion bar to the arm mechanism, at the end of the torsion bar, a serration formed by cutting or the like is fitted into a hole formed in a torque arm which is a part of the arm mechanism, thereby fixing the rotation direction.

[0004] In addition, although a steel torsion bar has the disadvantages of being long and heavy, it is desired to reduce the weight of the torsion bar by using a fiber reinforced synthetic resin (hereinafter also referred to as FRP) (see Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Conventionally, it has been difficult to form serrations at the ends of a torsion bar made of FRP due to the difficult-to-machine property caused by the presence of fibers and the concern about strength reduction due to fiber cutting. Also, due to variations in the material itself, it has been difficult for FRP to achieve a shape accuracy sufficient to withstand press-fitting. Therefore, when forming a torsion bar using FRP, it is necessary to individually machine the torque arms according to the shape of the ends.

[0007] One object of an embodiment of the present invention is to securely fix a torsion bar without machining the FRP at the ends of the torsion bar made of FRP.

Means for Solving the Problems

[0008] A torsion bar unit according to an embodiment of the present invention comprises a torsion bar having a cylindrical shape extending in a first direction and made of a fiber-reinforced composite material, a first holding member having a first groove portion for holding an end portion of the torsion bar, and a second holding member having a second groove portion for holding the end portion of the torsion bar at a position facing the first groove portion, and by overlapping the first holding member, the end portion of the torsion bar is sandwiched and held by the first groove portion and the second groove portion.

[0009] In the above configuration, it further has a mandrel inserted into the cylindrical hollow portion at the end portion.

[0010] In the direction in which the mandrel is inserted into the cylindrical hollow portion, the corner portion of the tip of the mandrel has a rounded shape or a tapered shape.

[0011] In the above configuration, the shape of the end portion of the torsion bar is a polygonal cylindrical shape.

[0012] In the above configuration, the polygonal cylindrical shape is a square cylindrical shape, a hexagonal cylindrical shape, or an octagonal cylindrical shape.

[0013] In the above configuration, the second holding member has a through hole near the second groove portion, the first holding member has a bolt hole at a position facing the through hole, and the first holding member is fixed to the second holding member by a bolt inserted into the through hole of the second holding member.

[0014] In the above configuration, the second holding member has an inlay convex portion protruding from a surface facing the first holding member near the second groove portion and a through hole penetrating the inlay convex portion, and the first holding member has an inlay concave portion engaging with the inlay convex portion and a bolt hole formed on the bottom surface of the inlay concave portion and provided at a position corresponding to the through hole.

[0015] In the above configuration, the second holding member has an inlay concave portion provided on a surface facing the first holding member near the second groove portion and a through hole penetrating the inlay concave portion, and the first holding member has an inlay convex portion engaging with the inlay concave portion and a bolt hole provided at a position corresponding to the through hole in the inlay convex portion.

[0016] In the above configuration, the first holding member is fixed to the second holding member by an adhesive.

[0017] In the above configuration, the first groove portion extends along the first direction, a third groove portion is provided in the first groove portion, the second groove portion extends along the first direction, and a fourth groove portion is provided in the second groove portion.

[0018] In the above configuration, the first holding member and the second holding member are fixed by welding.

[0019] In the above configuration, the thickness of the end portion is thicker than the thickness of the portion other than the end portion in the torsion bar.

[0020] The first holding member is integrally formed with a suspension arm, an anchor arm, or a torque arm.

Advantages of the Invention

[0021] According to an embodiment of the present invention, the torsion bar can be securely fixed without processing the FRP at the end of the torsion bar using FRP.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11A

Figure 11B

Figure 12

Modes for Carrying Out the Invention

[0023] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. However, the present invention can be implemented in various forms without departing from the gist thereof, and should not be construed as being limited to the description of the embodiments exemplified below.

[0024] For the sake of clearer explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but this is merely an example and does not limit the interpretation of the present invention. Also, in each embodiment of the present invention, elements having the same functions as those described with respect to the previously shown drawings may be denoted by the same reference numerals, and redundant explanations may be omitted.

[0025] In this specification and the like, when collectively representing a plurality of identical or similar configurations, they may be denoted by the same reference numeral or the same reference numeral with a capital letter appended. When separately denoting a plurality of parts within one configuration, the same reference numeral may be used, and further, a hyphen and a natural number may be used.

[0026] In this specification and the like, the characters such as "first", "second", or "third" appended to each configuration are for convenience in distinguishing each configuration and have no further meaning unless otherwise specified.

[0027] (First Embodiment) In this embodiment, a torsion bar unit 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 12.

[0028] FIG. 1 is a schematic view of a torsion bar unit 100 according to an embodiment of the present invention. FIG. 2A is an overall view of the torsion bar 110, and FIG. 2B is an enlarged view of an end portion 112 of the torsion bar 110. The torsion bar unit 100 includes a torsion bar 110, and holding members 121 and 122 that hold the torsion bar 110. The torsion bar unit 100 fixes one end portion 112 of the torsion bar 110 by the holding members 121 and 122, and attaches the other end portion 112 to a torque arm or the like, thereby realizing a spring mechanism.

[0029] As shown in FIG. 2A, the torsion bar 110 is made of a fiber-reinforced composite material and has a cylindrical shape extending in a first direction. As the fiber-reinforced composite material, for example, a fiber-reinforced plastic such as carbon fiber-reinforced plastic, glass fiber-reinforced plastic, or aramid fiber-reinforced plastic is used. As the fiber, natural-derived fibers such as CNF (cellulose nanofiber), basalt fiber, or flax fiber may be used. Examples of the matrix resin of the fiber-reinforced composite material include epoxy, polyurethane, and unsaturated polyester. The compressive strength of epoxy is 103 MPa to 173 MPa, the compressive strength of polyurethane is 138 MPa, and that of unsaturated polyester is 89 MPa to 207 MPa.

[0030] The torsion bar 110 has a main body portion 111 and an end portion 112. Here, the main body portion 111 of the torsion bar 110 refers to the portion other than the end portion 112. As shown in FIG. 2B, in the torsion bar 110, the cylindrical shape of the end portion 112 is different from the cylindrical shape of the main body portion 111. While the shape of the main body portion 111 is cylindrical, the shape of the end portion 112 is polygonal cylindrical. In the torsion bar 110, a cylindrical space (also referred to as the hollow portion 113) is provided across the main body portion 111 and the end portion 112. That is, the inner diameter (diameter of the cylinder) of the polygonal cylindrical shape of the end portion 112 is substantially the same as the inner diameter (diameter of the cylinder) of the cylindrical shape of the main body portion 111. In this specification and the like, the direction in which the torsion bar 110 extends is referred to as the first direction D1. The torsion bar 110 is formed, for example, by a sheet winding method or a filament winding method. The torsion bar 110 is formed by winding a sheet or filamentous material around a mandrel for molding and compressing only the end portion 112 with a mold or the like to form a polygonal cylindrical shape. Since the end portion 112 is compressed with a mold or the like, it becomes thinner compared to the thickness of the main body portion 111.

[0031] The end portion 112 of the torsion bar 110 is a portion held by being sandwiched between a holding member 121 and a holding member 122. Therefore, it is preferable that the end portion 112 of the torsion bar 110 has high compressive strength. As the matrix resin of the fiber-reinforced composite material, the materials listed above are suitable because they have high compressive strength.

[0032] In order to increase the compressive strength of the end portion 112, a mandrel 130 may be provided in the cylindrical hollow portion 113 of the end portion 112 of the torsion bar 110. Examples of the material of the mandrel 130 include metals such as iron, steel, and aluminum, alloys, or hard resins. It is preferable that the compressive strength of the mandrel 130 is higher than the compressive strength of the matrix resin. As the material of the mandrel, a material having a higher compressive strength than the compressive strength of the matrix resin may be appropriately selected. In FIG. 2B, the mandrel 130 is illustrated as a solid material, but an embodiment of the present invention is not limited thereto, and the mandrel 130 may be a hollow material.

[0033] Figures 3A and 3B are enlarged views of the end portion 112 of the torsion bar 110. In the direction (first direction D1) of inserting the mandrel 130 into the cylindrical hollow portion 113, the corner portion 131b of the tip portion 131a of the mandrel 130 may be chamfered. The chamfering is preferably R-chamfering or C-chamfering. C-chamfering is a method of chamfering the pin angle at an angle of 45 degrees in a plane. R-chamfering is a method of rounding the corner. As shown in FIG. 3A, it is preferable that the corner portion 131b of the tip portion 131a of the mandrel 130 has a tapered shape (C-chamfering). Alternatively, as shown in FIG. 3B, it is preferable that the mandrel 130 has a shape in which the corner portion 131b of the tip portion 131a is rounded (R-chamfering). When the corner portion 131b of the tip portion 131a of the mandrel 130 has a tapered shape or a rounded shape, it becomes easier to insert the mandrel 130 into the hollow portion 113. Alternatively, when the mandrel 130 is inserted into the hollow portion 113, damage to the hollow portion 113 of the torsion bar 110 can be suppressed.

[0034] The shape of the end portion 112 of the torsion bar 110 is a polygonal cylinder shape. In other words, the cross-sectional shape of the end portion 112 along the second direction D2 perpendicular to the first direction D1 in which the torsion bar 110 extends is a polygon. Each corner of the polygonal cylinder shape may be chamfered. The chamfering is preferably R-chamfering or C-chamfering. In the present embodiment, the shape of the end portion 112 is a square cylinder shape, and the case where each corner of the square cylinder shape is chamfered will be described, but one embodiment of the present invention is not limited thereto. For example, the shape of the end portion 112 may be a triangular cylinder shape, a pentagonal cylinder shape, a hexagonal cylinder shape, a heptagonal cylinder shape, an octagonal cylinder shape, or the like. Considering the ease of forming the end portion 112 of the torsion bar 110, the shape of the torsion bar 110 is preferably a square cylinder shape, a hexagonal cylinder shape, or an octagonal cylinder shape. Further, each corner of the polygonal cylinder shape may not be chamfered along the first direction D1.

[0035] In this embodiment, a case where the thickness of the end portion 112 of the torsion bar 110 is thinner than the thickness of the main body portion 111 will be described. Here, the thickness of the end portion 112 refers to the diameter of the inscribed circle of the cross-sectional shape at the end portion 112. Further, since the cross-sectional shape of the main body portion 111 is circular, the thickness of the main body portion 111 refers to the diameter of the circle.

[0036] Next, the length of the mandrel 130 inserted into the end portion 112 of the torsion bar 110 will be described with reference to FIGS. 4A and 4B.

[0037] FIG. 4A illustrates a case where the length L2 of the mandrel 130 is shorter than the length L1 of the end portion 112. FIG. 4B illustrates a case where the length L2 of the mandrel 130 is longer than the length L1 of the end portion 112. As illustrated, the length L2 of the mandrel 130 in the first direction may be longer than, shorter than, or the same as the length L1 of the end portion 112 in the first direction D1. It may be appropriately set according to the required characteristics.

[0038] FIG. 5 is a front view of the holding members 121 and 122. The holding member 121 has a groove portion 1212 so as to hold the end portion 112 of the torsion bar 110 from the third direction D3. The holding member 122 has a groove portion 1222 that holds the end portion 112 of the torsion bar 110 from the third direction D3 at a position facing the groove portion 1212. Further, each of the groove portion 1212 and the groove portion 1222 extends along the first direction D1. In the holding member 121, the surface on which the groove portion 1212 is formed is referred to as the first surface 1211. Also, in the holding member 122, the surface on which the groove portion 1222 is formed is referred to as the first surface 1221. Examples of the materials of the holding members 121 and 122 include metals such as iron, steel, and aluminum, alloys, or hard resins, but are not particularly limited.

[0039] When the holding member 121 and the holding member 122 are overlapped, by opposing the groove portion 1212 and the groove portion 1222, a shape corresponding to the shape of the end portion 112 of the torsion bar 110 is obtained. In the present embodiment, since the outer shape of the end portion 112 is a quadrangular prism, a quadrangular prism shape is formed by opposing the groove portion 1212 and the groove portion 1222. For example, when the outer shape of the end portion 112 is a hexagonal prism, the shape formed by the groove portion 1212 and the groove portion 1222 is a hexagonal prism. Note that the outer shape of the end portion 112 and the shape formed by opposing the groove portion 1212 and the groove portion 1222 may be different. Even when the outer shape of the end portion 112 is a hexagonal prism, the shape formed by the groove portion 1212 and the groove portion 1222 may be a rhombus that holds only four sides out of the six sides of the hexagonal prism. The end portion 112 can be held by sandwiching the end portion 112 of the torsion bar 110 between the groove portion 1212 of the holding member 121 and the groove portion 1222 of the holding member 122.

[0040] In FIG. 1, the cross-sectional shape of the end portion 112 is a quadrangle, and the direction of one axis of the diagonal of the quadrangle substantially coincides with the second direction D2. By adopting such a shape, high machining accuracy is not required when forming the groove portion 1212 and the groove portion 1222. In the present embodiment, the case where the direction of one axis of the diagonal of the quadrangle substantially coincides with the second direction D2 will be described, but an embodiment of the present invention is not limited thereto. When the cross-sectional shape of the end portion 112 is a quadrangle, the groove portion 1212 and the groove portion 1222 may be formed such that the direction of one axis of the symmetry line of the quadrangle substantially coincides with the second direction D2.

[0041] As shown in FIG. 5, the groove portion 1212 has inner walls 1212a, 1212b, and a ridge 1212c sandwiched between the inner wall 1212a and the inner wall 1212b. Similarly, the groove portion 1222 also has inner walls 1222a, inner walls 1222b, and a ridge 1222c sandwiched between the inner wall 1222a and the inner wall 1222b. The ridges 1212c, 1222c may be rounded.

[0042] As shown in FIG. 1, the holding member 122 has a through hole 1223 near the groove portion 1222. The holding member 121 has bolt holes (not shown in FIG. 1) at positions facing the through hole 1223 near the groove portion 1212. In FIG. 1, four through holes 1223 are provided near the groove portion 1222. Also, four bolt holes are provided near the groove portion 1212. The positions of the four through holes 1223 face the positions of the four bolt holes. After the end portion 112 is sandwiched between the holding member 121 and the holding member 122, bolts are inserted into the through hole 1223 and the bolt holes. Thereby, the holding member 121 and the holding member 122 can be firmly fixed. The number of through holes provided in the holding member 122 is not limited to four, and may be appropriately set according to the size of the holding member 122 and the size of the groove portion 1222. Also, the bolt holes provided in the holding member 121 may be appropriately set according to the position where the through holes are provided.

[0043] FIG. 6 is a front view of the holding member 121 and the holding member 122 in a state where the end portion 112 of the torsion bar 110 is sandwiched. As shown in FIG. 6, it is preferable that a gap L3 is provided between the holding member 121 and the holding member 122. The gap L3 is also referred to as a tightening allowance. By providing a tightening allowance between the holding member 121 and the holding member 122, the end portion 112 can be firmly fixed when the holding member 121 and the holding member 122 are fixed by bolts.

[0044] Conventionally, for a torsion bar using FRP, it has been difficult to form serrations at the end portions due to the difficult-to-machine property caused by the presence of fibers and the concern about strength reduction due to fiber cutting. FRP has difficulty achieving shape accuracy sufficient to cope with press-fitting due to variations in the material itself. Therefore, when forming a torsion bar using FRP, it is necessary to individually machine the torque arms according to the shape of the end portions.

[0045] The torsion bar unit 100 according to an embodiment of the present invention has an end portion 112 of a torsion bar 110 in a polygonal cylinder shape, and is held between a holding member 121 and a holding member 122 in which groove portions 1212 and 1222 corresponding to the polygonal cylinder shape of the end portion 112 are formed. Since the end portion 112 of the torsion bar 110 can be fixed using the holding member 121 and the holding member 122, in the torsion bar 110 using FRP, there is no need to process the end portion 112 after molding the torsion bar 110. Since there is no need to individually process the torque arms according to the shape of the end portion 112, the manufacturing cost can be reduced. Further, since the end portion 112 of the torsion bar 110 is structured to be fixed by bolts to the holding member 121 and the holding member 122, the end portion 112 of the torsion bar 110 can be securely fixed. Also, the torsion bar 110 can be easily replaced.

[0046] (Modification 1) In the present embodiment, the case where the through holes 1223 provided in the holding member 122 and the bolt holes provided in the holding member 121 face each other has been described, but an embodiment of the present invention is not limited thereto. The holding member 121 and the holding member 122 may be engaged by an inlay structure.

[0047] FIG. 7 is a diagram showing a first surface 1221 of the holding member 122. FIG. 8 is a diagram showing a first surface 1211 of the holding member 121. As shown in FIG. 7, in the vicinity of the groove portion 1222, through holes 1223a to 1223d are formed at four positions. The through holes 1223a to 1223d are arranged along the groove portion 1222. In the peripheral portions of the through holes 1223a and 1223b, inlay convex portions 1225a and 1225b protruding from the first surface 1221 are provided. In other words, the through holes 1223a and 1223b are provided so as to penetrate the inlay convex portions 1225a and 1225b.

[0048] As shown in FIG. 8, in the vicinity of the groove portion 1212, bolt holes 1214a to 1214d corresponding to the through holes 1223a to 1223d are formed at four locations. The bolt holes 1214a to 1214d are arranged along the groove portion 1212. In the peripheral portions of the bolt holes 1214a and 1214b, inro recesses 1215a and 1215b that engage with the inro protrusions 1225a and 1225b are provided. In other words, the bolt holes 1214a and 1214b are provided on the bottom surfaces of the inro recesses 1215a and 1215b. When the holding member 121 and the holding member 122 are faced to each other, the inro protrusions 1225a and 1225b protruding from the first surface 1221 are fitted into the inro recesses 1215a and 1215b provided on the first surface 1211. Thereby, the positioning of the holding member 121 and the holding member 122 can be facilitated. In this state, bolts are inserted into and fixed to each of the through holes 1223a to 1223d. Thereby, the holding member 121 and the holding member 122 can be firmly fixed.

[0049] In FIG. 7, the inro protrusions 1225a and 1225b are provided so as not to be adjacent in both the first direction D1 and the second direction D2. In FIG. 8, the inro recesses 1215a and 1215b are provided so as not to be adjacent in both the first direction D1 and the second direction D2. Thereby, the positioning accuracy between the holding member 121 and the holding member 122 is improved. Also, the rigidity against the relative displacement between the holding member 121 and the holding member 122 is improved.

[0050] In FIG. 7, the case where the inro protrusions 1225a and 1225b are provided so as not to be adjacent in both the first direction D1 and the second direction D2 has been described, but an embodiment of the present invention is not limited thereto. The inro protrusions may be provided in all of the through holes. Also, a plurality of inro protrusions may be adjacent in the first direction D1 or the second direction D2.

[0051] Also, in FIG. 8, the inlay recesses 1215a and 1215b have been described as being provided so as not to be adjacent in both the first direction D1 and the second direction D2. However, an embodiment of the present invention is not limited to this. If inlay protrusions are provided in all of the through holes of the holding member 122, the inlay recesses may also be provided in all of the bolt holes. Thus, the number of the inlay protrusions and the inlay recesses may be appropriately set according to the size of the holding member 121 and the size of the groove portion 1212.

[0052] In FIG. 7, an example in which inlay protrusions 1225a and 1225b are provided on the holding member 122 and in FIG. 8, inlay recesses 1215a and 1215b are provided on the holding member 121 has been shown. However, an embodiment of the present invention is not limited to this. Instead of the positions where the inlay recesses 1215a and 1215b are provided on the holding member 121, inlay protrusions may be provided, and instead of the positions where the inlay protrusions 1225a and 1225b are provided on the holding member 122, inlay recesses may be provided. In this case, the holding member 122 may have an inlay recess provided on a surface facing the holding member 121 in the vicinity of the groove portion 1222 and a through hole 1223 penetrating the inlay recess, and the holding member 121 may have an inlay protrusion engaging with the inlay recess and a bolt hole provided at a position corresponding to the through hole 1223 in the inlay protrusion.

[0053] (Modification 2) In the present embodiment, the case where the shape of the end portion 112 of the torsion bar 110 is a square tube shape has been described. However, an embodiment of the present invention is not limited to this. For example, as shown in FIG. 9, the shape of the end portion 112 may be an octagonal tube shape.

[0054] When the shape of the end portion 112 is an octagonal tube shape, the shape formed by the groove portion 1212 and the groove portion 1222 facing each other is an octagonal prism. Also, even when the outer shape of the end portion 112 is an octagonal prism, the shape formed by the groove portion 1212 and the groove portion 1222 may be a diamond shape that holds only 4 sides out of the 8 sides of the octagonal prism. Further, when the cross-sectional shape of the end portion 112 is an octagon, one axis direction of the diagonal of the octagon substantially coincides with the second direction D2. By adopting such a shape, high machining accuracy is not required when forming the groove portion 1212 and the groove portion 1222, which is preferable. Also, since the octagonal tube shape is closer to the cylindrical shape than the square tube shape and the hexagonal tube shape, the stress generated by torsion is made uniform.

[0055] In addition, in the present embodiment, the case where one axis direction of the diagonal of the polygon substantially coincides with the second direction D2 has been described, but one embodiment of the present invention is not limited to this. The groove portion 1212 and the groove portion 1222 may be formed such that one axis of the symmetry line of the polygon coincides with the second direction D2.

[0056] (Modification 3) In the present embodiment, the case where the thickness of the end portion 112 of the torsion bar 110 is thinner than the thickness of the main body portion 111 has been described, but one embodiment of the present invention is not limited to this. The thickness of the end portion 112 may be thicker than the thickness of the main body portion 111.

[0057] FIG. 10 is an enlarged view of an end portion 112 of a torsion bar 110. For example, the diameter of the inscribed circle of the cross-sectional shape at the end portion 112 may be larger than the diameter of the cross-sectional shape of the main body portion 111 of the torsion bar 110. In this case, when holding the torsion bar 110 between the holding members 121 and 122, the compressive strength of the end portion 112 can be improved. Further, when the diameter of the inscribed circle of the cross-sectional shape at the end portion 112 is larger than the diameter of the cross-sectional shape of the main body portion 111 of the torsion bar 110, the shape may be such that stress concentration does not occur at the boundary between the main body portion 111 and the end portion 112. For example, at the boundary between the end portion 112 and the main body portion 111, the shape may be such that the diameter of the inscribed circle of the cross-sectional shape continuously changes. When forming the torsion bar 110, by winding a sheet or filamentous material around the end portion 112 more times than the main body portion 111, the thickness of the end portion 112 can be made larger than the thickness of the main body portion 111.

[0058] In FIG. 10, the case where the shape of the end portion 112 is a square tube shape has been described, but even if the shape of the end portion 112 is another polygonal tube shape, it is the same as the case of the square tube shape.

[0059] (Modification 4) In the present embodiment, the method of fixing the holding members 121 and 122 with bolts has been described, but one embodiment of the present invention is not limited to this. The holding members 121 and 122 may be fixed with an adhesive. In this case, when the end portion 112 of the torsion bar 110 is sandwiched between the holding members 121 and 122, no gap (tightening allowance) is provided between the holding members 121 and 122.

[0060] FIG. 11A is a view showing a first surface 1211 of the holding member 121. As shown in FIG. 11A, a groove portion 1216 is provided in the groove portion 1212 of the holding member 121. The groove portion 1216 extends along a direction intersecting the direction in which the groove portion 1212 extends. Although not shown, a groove also extends in the holding member 122 in a direction intersecting the direction in which the groove portion 1222 extends. The groove portion provided in the holding member 122 may face the groove portion 1216.

[0061] When fixing the holding member 121 and the holding member 122 with an adhesive, apply the adhesive to the first surface 1211 and the groove portion 1212 of the holding member 121, and the first surface 1221 and the groove portion 1222 of the holding member 122. Then, with the end portion 112 sandwiched therebetween, bond the first surface 1211 and the first surface 1221, and bond the groove portion 1212, the groove portion 1222, and the end portion 112. At this time, the adhesive enters the groove portion 1216 and the groove portion provided in the holding member 122. Thereby, it is possible to suppress the adhesive from oozing out.

[0062] FIG. 11B is a diagram showing the first surface 1211 of the holding member 121. As shown in FIG. 11B, the groove portion 1218 extends along a direction parallel to the direction in which the groove portion 1212 extends. The groove portion 1219 extends along a direction parallel to the direction in which the groove portion 1222 extends. The position where the groove portion 1218 is provided corresponds to the ridge 1212c shown in FIG. 5. The position where the groove portion 1219 is provided corresponds to the ridge 1222c shown in FIG. 5. The groove portions 1218 and 1219 can suppress the adhesive from oozing out.

[0063] Even when the holding member 121 and the holding member 122 are fixed by bolts, the end portion 112 may be fixed by an adhesive. As shown in FIGS. 7 and 8, even when an inlay structure is formed by the holding member 121 and the holding member 122, the holding member 121 and the holding member 122 may be bonded by an adhesive. For example, in the holding member 121 shown in FIG. 8, a groove portion extending in a direction intersecting the direction in which the groove portion 1212 extends may be provided, or a groove portion extending in a direction parallel to the direction in which the groove portion 1212 extends may be provided. In the holding member 122 shown in FIG. 7, a groove portion extending in a direction intersecting the direction in which the groove portion 1222 extends may be provided, or a groove portion extending in a direction parallel to the direction in which the groove portion 1222 extends may be provided. By fixing the holding member 121 and the holding member 122 with bolts and using an adhesive, the holding member 121 and the holding member 122 can be firmly fixed.

[0064] In FIGS. 11A and 11B, the groove portion 1216 intersecting the groove portion 1212 is shown for the case where it is provided at one location, but it may be provided at a plurality of locations. Similarly, the groove portions intersecting the groove portion 1222 provided in the holding member 122 may be provided at a plurality of locations.

[0065] Further, the end portion 112 of the torsion bar 110 may be fixed by welding the holding member 121 and the holding member 122. In this case, there may be a gap (tightening allowance) between the holding member 121 and the holding member 122 in a state where the end portion 112 of the torsion bar 110 is sandwiched between the holding member 121 and the holding member 122. It is preferable to perform welding while applying a load in a state where the end portion 112 is sandwiched between the holding member 121 and the holding member 122. Further, the through hole provided in the holding member 121 and the bolt hole provided in the holding member 122 can be omitted. By fixing the holding member 121 and the holding member 122 by welding, the end portion 112 can be firmly fixed by the holding member 121 and the holding member 122.

[0066] (Modification 5) In the present embodiment, the case where the torsion bar unit 100 is attached to the torque arm has been described, but an embodiment of the present invention is not limited thereto. For example, one of the holding members 121 and 122 may be integrally formed with a vehicle body, an arm, or the like. Further, it may be integrally formed with a suspension arm, an anchor arm, a torque arm, or the like.

[0067] FIG. 12 is a schematic view of a torsion bar unit 200. As shown in FIG. 12, one end portion 112 of the torsion bar 110 is held by being sandwiched between a holding member 121A and a holding member 122A. The holding member 121A functions as a suspension arm. The holding member 122A is fixed to the holding member 121A by a bolt (not shown). For the mechanism of sandwiching and holding the end portion 112 by the holding member 121A and the holding member 122A, reference may be made to the description of the holding member 121 and the holding member 122 in FIGS. 1 to 11B.

[0068] The other end 112 of the torsion bar 110 is held sandwiched between a holding member 141 and a holding member 142. The holding member 141 and the holding member 142 are provided on the vehicle body side. The holding member 142 is fixed to the holding member 141 by a bolt (not shown). For the mechanism that holds the end 112 by sandwiching it between the holding member 141 and the holding member 142, reference may be made to the description of the holding member 121 and the holding member 122 in FIGS. 1 to 11B. The holding member 141 is connected to a vehicle height adjustment bolt 151. The vehicle height adjustment bolt 151 is connected to the vehicle body by a fixing portion 152. As shown in FIG. 12, at least one of the holding members 121 and 122 and at least one of the holding members 141 and 142 are integrally formed with other components, whereby the number of components can be reduced.

[0069] The torsion bar units 100, 200, etc. described above as embodiments of the present invention can be implemented in appropriate combinations as long as they do not conflict with each other. Also, based on each embodiment, those in which a person skilled in the art appropriately adds, deletes, or changes the design of components are included in the scope of the present invention as long as they have the gist of the present invention.

[0070] Also, other operational effects different from those brought about by the above-described embodiments, which are obvious from the description in this specification or can be easily predicted by a person skilled in the art, are naturally understood to be brought about by the present invention.

Description of Reference Numerals

[0071] 100, 200: Torsion bar unit, 110: Torsion bar, 111: Main body part, 112: End part, 113: Hollow part, 121, 122: Holding members, 130: Mandrel, 131a: Tip part, 131b: Corner part, 141, 142: Holding members, 151: Vehicle height adjustment bolt, 152: Fixed part, 1211: First surface, 1212: Groove part, 1212a, 1212b: Inner walls, 1212c: Ridge, 1214a - 1214d: Bolt holes, 1215a, 1215b: Inlet recesses, 1216: Groove part, 1221: First surface, 1222: Groove part, 1222a, 1222b: Inner walls, 1222c: Ridge, 1223: Through hole, 1223a - 1223d: Through holes, 1225a, 1225b: Inlet protrusions

Claims

1. A torsion bar unit comprising a tubular torsion bar made of a fiber-reinforced composite material and extending in a first direction, a first holding member having a first groove for holding an end portion of the torsion bar, a second holding member having a second groove for holding the end portion of the torsion bar at a position facing the first groove, and sandwiching and holding the end portion of the torsion bar between the first groove and the second groove by overlapping the first holding member, and a mandrel inserted into the tubular hollow portion at the end portion.

2. The torsion bar unit according to claim 1, wherein, in a direction in which the mandrel is inserted into the tubular hollow portion, a corner portion of a tip end portion of the mandrel has a rounded shape or a tapered shape.

3. The torsion bar unit according to claim 1, wherein a shape of the end portion of the torsion bar is a polygonal tubular shape.

4. The torsion bar unit according to claim 3, wherein the polygonal tubular shape is a square tubular shape, a hexagonal tubular shape, or an octagonal tubular shape.

5. The second holding member has a through hole in the vicinity of the second groove, the first holding member has a bolt hole at a position facing the through hole, and the first holding member is fixed to the second holding member by a bolt inserted into the through hole of the second holding member. The torsion bar unit according to claim 1.

6. A torsion bar unit comprising a tubular torsion bar made of a fiber-reinforced composite material and extending in a first direction, a first holding member having a first groove for holding an end portion of the torsion bar, a second holding member having a second groove for holding the end portion of the torsion bar at a position facing the first groove, and sandwiching and holding the end portion of the torsion bar between the first groove and the second groove by overlapping the first holding member, wherein the second holding member has an inlay convex portion protruding from a surface facing the first holding member in the vicinity of the second groove, and a through hole penetrating the inlay convex portion, and the first holding member has an inlay concave portion engaging with the inlay convex portion, and a bolt hole formed on a bottom surface of the inlay concave portion and provided at a position corresponding to the through hole.

7. A torsion bar unit comprising a tubular torsion bar made of a fiber-reinforced composite material and extending in a first direction, a first holding member having a first groove for holding an end portion of the torsion bar, It has a second groove portion that holds the end portion of the torsion bar at a position facing the first groove portion, and by overlapping the first holding member, it has a second holding member that sandwiches and holds the end portion of the torsion bar between the first groove portion and the second groove portion. The second holding member has an inlay recess provided on a surface facing the first holding member in the vicinity of the second groove portion, and a through hole penetrating the inlay recess. The first holding member has an inlay projection that engages with the inlay recess, and a bolt hole provided at a position corresponding to the through hole in the inlay projection, and is a torsion bar unit.

8. The first holding member is fixed to the second holding member by an adhesive, and the torsion bar unit according to claim 1.

9. The first groove portion extends along the first direction. A third groove portion is provided in the first groove portion. The second groove portion extends along the first direction. A fourth groove portion is provided in the second groove portion, and the torsion bar unit according to claim 8.

10. The first holding member and the second holding member are fixed by welding, and the torsion bar unit according to claim 1.

11. The thickness of the end portion is thicker than the thickness of the portion other than the end portion in the torsion bar, and the torsion bar unit according to claim 1.

12. The first holding member is integrally formed with a suspension arm, an anchor arm, or a torque arm, and the torsion bar unit according to claim 1.

13. It further has a mandrel inserted into the cylindrical hollow portion at the end portion, and the torsion bar unit according to claim 6 or 7.

14. In the direction in which the mandrel is inserted into the cylindrical hollow portion, the corner portion of the tip of the mandrel has a rounded shape or a tapered shape, and the torsion bar unit according to claim 13.

15. The shape of the end portion of the torsion bar is a polygonal cylindrical shape, and the torsion bar unit according to claim 6 or 7.

16. The polygonal cylindrical shape is a square cylindrical shape, a hexagonal cylindrical shape, or an octagonal cylindrical shape, and the torsion bar unit according to claim 15.

17. The first holding member is fixed to the second holding member by a bolt inserted into the through hole of the second holding member, and the torsion bar unit according to claim 6 or 7.

18. The torsion bar unit according to claim 6 or 7, wherein the first holding member is fixed to the second holding member by an adhesive material.

19. The first groove portion extends along the first direction, a third groove portion is provided in the first groove portion, the second groove portion extends along the first direction,

20. The torsion bar unit according to claim 18, wherein a fourth groove portion is provided in the second groove portion.

20. The torsion bar unit according to claim 6 or 7, wherein the thickness of the end portion is thicker than the thickness of the portion other than the end portion in the torsion bar.

21. The torsion bar unit according to claim 6 or 7, wherein the first holding member is integrally formed with a suspension arm, an anchor arm, or a torque arm.

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