Connecting strut for a vehicle

Abstract

Connecting strut (1) for a vehicle with: a rod section (10) which is formed into a solid rod shape; and two coupling sections (20a, 20b), each having a ring shape, wherein the two coupling sections (20a, 20b) are arranged at both ends of the rod section (10) and each have a bearing eye (21) into which a coupling element (50) can be inserted, which can be coupled to either a vehicle body element or a wheel bearing element, wherein the connecting strut (1) is entirely made of a fiber-reinforced plastic, the two coupling sections (20a, 20b) each comprise a plastic (A) reinforced with continuous fibers, in which the continuous fibers are aligned along a circumferential direction of the bearing eye (21) over a region at a distal end side of the connecting strut (1) which extends continuously around at least half a circumference (R1) about a central axis (L2) of the bearing eye (21), wherein the region includes a position which lies in a plane (Fa, Fb) which is perpendicular to a straight line (L1) which connects the centers (Oa, Ob) of the bearing eyes (21), wherein the plane passes through the center (Oa, Ob) of the bearing eye (21), characterized in that the fiber-reinforced plastic comprises the plastic (A) reinforced with continuous fibers in which continuous fibers are bonded together by a synthetic resin, and a plastic (B) reinforced with randomly distributed fibers in which non-continuous fibers are bonded together by a synthetic resin in random orientations, and the rod section (10) comprises the plastic (B) reinforced with randomly distributed fibers.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to a connecting strut or a suspension arm for a vehicle according to the preamble of claim 1. 2. Explanation of the state of the art

[0002] A connecting strut for a vehicle is an element designed to couple a vehicle body component and a wheel bearing component using coupling elements. For example, the connecting strut comprises a rod section and annular coupling sections at both ends of the rod section. Each coupling section has a bearing eye into which an elastic sleeve or a ball joint is inserted. One of the coupling sections is coupled to a suspension component, the vehicle body component, and the other coupling section is coupled to a support, the wheel bearing component.

[0003] In recent years, a connecting strut has also become known that is made from a fiber-reinforced plastic instead of a previously used metal (iron or aluminum) in order to achieve a reduction in weight.

[0004] For example, in a connecting strut disclosed in DE 10 2013 007 284 A1, the strut is made entirely of fiber-reinforced plastic in which continuous fibers are impregnated with a synthetic resin.

[0005] The connecting strut is positioned between the vehicle body element and the wheel bearing element, and thus a tensile and a compressive load act primarily in one axial direction of the rod section. The closed-fiber reinforced plastic exhibits high tensile strength in one direction of the continuous fibers, but low compressive strength in the opposite direction to the tensile load. In the connecting strut proposed in DE 10 2013 007 284 A1, the continuous fibers of the rod section are oriented in the axial direction of the rod section. Therefore, this connecting strut is strong with respect to the tensile load acting on the rod section, but weak with respect to the compressive load acting on the rod section.

[0006] DE 10 2015 216 966 A1 discloses a strut according to the preamble of claim 1.

[0007] In light of this, a structure is considered in which the connecting strut is entirely made of a plastic reinforced with non-directional or randomly distributed fibers, in which discontinuous fibers are randomly oriented as reinforcing fibers. The plastic reinforced with randomly oriented fibers exhibits high compressive strength but low tensile strength. As in Fig. Figure 4 illustrates that the maximum possible tensile load in the connecting strut acts on sections W in bearing eyes or coupling sections Y, which are located at both ends of a strut section X. If the connecting strut is made of a plastic reinforced with randomly oriented fibers, the sections W become the weakest sections with the lowest tensile strength, and thus the necessary fatigue strength is not achieved. Fig. Figure 4 illustrates an elastic sleeve Z and a bearing eye U into which the elastic sleeve Z is inserted. SUMMARY OF THE INVENTION

[0008] The present invention was made to solve the problem explained above, and its objective is to create a connecting strut that has the required strength and is weight-reduced.

[0009] According to the present invention, a connecting strut or suspension arm for a vehicle is created with the features listed in claim 1.

[0010] The connecting strut for a vehicle according to the present invention comprises the rod section, which is designed as a solid rod, and the two coupling sections arranged at both ends of the rod section. The connecting strut is fully integrated and made of fiber-reinforced plastic. The coupling section has the bearing eye into which the coupling element can be inserted, which is to be coupled to a vehicle body element or a wheel carrier element. The coupling element is, for example, an elastic sleeve or a ball joint.

[0011] The fiber-reinforced plastic comprises continuous fiber-reinforced plastic, in which the continuous fibers are bonded together via a synthetic resin (a synthetic resin containing the continuous fibers as reinforcing fibers), and random fiber-reinforced plastic, in which the non-continuous fibers are bonded together via a synthetic resin in random orientations (a synthetic resin containing the randomly oriented non-continuous fibers as reinforcing fibers), and the continuous fiber-reinforced plastic and the random fiber-reinforced plastic are selected appropriately depending on the section of the connecting strut.

[0012] The rod section is made of plastic reinforced with randomly distributed fibers. Therefore, the rod section can maintain the required strength under both tensile and compressive loads. Meanwhile, the two coupling sections are each made of plastic reinforced with continuous fibers, in which the continuous fibers are oriented circumferentially around the bearing eye over the area on the distal end of the connecting strut. This continuous area extends at least half the circumference around the central axis of the bearing eye, encompassing the position in the plane perpendicular to the straight line connecting the centers of the bearing eyes and passing through the center of the bearing eye.Thus, the weakest section with the lowest strength with respect to (compared to) the tensile load is made of the plastic reinforced with continuous fibers, and thus the necessary strength can be maintained even in the weakest section.

[0013] In this case, in the fiber-reinforced plastic where the fibers are oriented in one direction, it is preferred that the fibers are arranged in a circumferential direction of the bearing eye such that they are parallel to a plane perpendicular to the central axis of the bearing eye. Furthermore, in the fiber-reinforced plastic where the fibers are woven into a fabric, it is only necessary that the fibers are arranged around the circumferential direction of the bearing eye when viewed from the direction of the central axis of the bearing eye.

[0014] According to one embodiment of the present invention, at least one of the two coupling sections comprises the area (R1, R2) which is made of the plastic reinforced with continuous fibers, wherein the area (R1, R2) is formed as an arc around the central axis of the bearing eye, and an area on the side of the rod section opposite the area (R1, R2) which is formed as the arc, wherein the area on the side of the rod section consists of the plastic reinforced with randomly distributed fibers.

[0015] According to one embodiment of the present invention, in at least one of the coupling sections, the continuous fiber-reinforced plastic is formed as an arc around the central axis of the bearing eye, and the area on the side of the rod section relative to the arc-shaped area of ​​the continuous fiber-reinforced plastic is made of randomly distributed fiber-reinforced plastic. The cost of the continuous fiber-reinforced plastic is higher than that of the randomly distributed fiber-reinforced plastic. Therefore, according to one embodiment of the present invention, the required tensile strength can be maintained at a lower cost.

[0016] According to one embodiment of the present invention, at least one of the two coupling sections comprises the area (R3) which is made of the plastic reinforced with continuous fibers, wherein the area is formed into a ring shape which surrounds the central axis of the bearing eye.

[0017] According to one embodiment of the present invention, the area formed from the continuous fiber-reinforced plastic in at least one of the coupling sections is designed as a ring around the central axis of the bearing eye. Thus, the composite surface in which the continuous fiber-reinforced plastic and the randomly distributed fiber-reinforced plastic are joined is not formed circumferentially around the central axis of the bearing eye, thereby improving fatigue strength. Furthermore, formability can be improved and manufacturing simplified.

[0018] According to one embodiment of the present invention, at least one of the two coupling sections is made from the plastic reinforced with continuous fibers in a radial direction in a part of the thickness, and is made from the plastic reinforced with randomly distributed fibers in a remaining part of the thickness in a radial direction.

[0019] According to one embodiment of the present invention, in at least one of the coupling sections, the portion of the thickness in the radial direction (the radial direction of the bearing eye) is made of the plastic reinforced with continuous fibers. Furthermore, the remaining portion of the thickness in the radial direction is made of the plastic reinforced with randomly distributed fibers. Thus, by determining the thickness of the plastic reinforced with continuous fibers with regard to the required strength, this strength can be maintained at low cost with respect to the tensile load.

[0020] According to one embodiment of the present invention, the continuous fibers and the randomly arranged fibers comprise carbon fibers.

[0021] According to one embodiment of the present invention, high-quality mechanical properties are obtained.

[0022] For better understanding of the invention, the structures of the invention used in the embodiment are identified by reference numerals in the description of the embodiment. However, it is not intended to limit the components of the invention by the embodiment discussed with reference numerals. BRIEF EXPLANATION OF THE FIGURES Fig. Figure 1 is a perspective view of a connecting strut according to an embodiment of the present invention. Fig. 2A, Fig. 2B and Fig. Figures 2C are each a sectional view to explain the arrangement of a plastic A reinforced with continuous fibers and a plastic B reinforced with randomly distributed fibers in a coupling section of the connecting strut seen from an axial direction of the coupling section. Fig. Figure 3 is a sectional view to illustrate the arrangement of the plastic A reinforced with continuous fibers and the plastic B reinforced with randomly distributed fibers in the coupling section of the connecting strut, viewed from an axial direction of the coupling section. Fig. Figure 4 is a view to illustrate the weakest sections with respect to the tensile load seen from the axial direction of the coupling section. Fig. Figure 5 is a perspective view to illustrate a method for manufacturing the connecting strut according to the embodiment. Fig. Figure 6 is a perspective view to illustrate the method for manufacturing the connecting strut according to the embodiment. EXPLANATION OF THE EXECUTION FORMS

[0023] A connecting strut for a vehicle according to one embodiment of the present invention will now be described with reference to the figures. The connecting strut for a vehicle is shown in the following embodiment: Fig. 1 shown.

[0024] A connecting strut 1 is an element designed to couple a vehicle body element and a wheel bearing element by connecting coupling elements. The connecting strut 1 is formed from an integrated rod section 10 and two coupling sections 20a and 20b, which are formed at both ends of the rod section 10. The two coupling sections 20a and 20b have a common basic structure and are therefore referred to below as "coupling section 20" unless a distinction is necessary for other reasons.

[0025] The rod section 10 is a solid, rod-shaped body formed into a rectangular prism shape with rounded edges in this embodiment. The rod section 10 of this embodiment is shaped as a curved rod to prevent collisions or mutual interference with other components, but it can also be shaped as a straight rod.

[0026] The coupling sections 20 are each annular bodies. One coupling section 20 (20a) is coupled to a vehicle body element (for example, a suspension element), and the other coupling section 20 (20b) is coupled to a wheel bearing element (for example, a support). Each of the coupling sections 20 has a bearing eye 21 into which an elastic sleeve or a ball joint, which is a coupling element, is inserted and fastened. The in Fig. 1. The illustrated connecting strut 1 is in a state in which an elastic sleeve 50 is mounted in the bearing eye 21. The elastic sleeve 50 has a cylindrical rubber-elastic body 52 which is firmly attached to an outer circumference of a metal cylindrical tube 51.

[0027] One coupling section 20 (20a) is coupled to the vehicle body element by inserting a (not shown) fastening bolt or fastening screw into the cylinder tube 51, and the other coupling section 20 (20b) is coupled to the wheel bearing element by inserting a (not shown) fastening bolt or fastening screw into the cylinder tube 51.

[0028] A connecting strut in the prior art consists of metal (iron or aluminum). However, for the purpose of weight reduction, the connecting strut 1 in this embodiment is manufactured entirely from carbon fiber reinforced plastic (CFRP), in which carbon fibers serving as reinforcing fibers are bonded together using synthetic resin. The connecting strut 1 is formed by using two types of carbon fiber reinforced plastics containing different forms of carbon fibers.One of the carbon fiber reinforced plastics is a plastic A, which is reinforced with continuous fibers, in which carbon fibers formed from continuous fibers are bonded together via a synthetic resin (a synthetic resin which includes the carbon fibers formed from continuous fibers as reinforcing fibers), and the other is a plastic B, which is reinforced with randomly distributed fibers, in which carbon fibers formed from discontinuous fibers, oriented in any direction, are bonded together via a synthetic resin (a synthetic resin which contains the carbon fibers formed from randomly oriented discontinuous fibers as reinforcing fibers).

[0029] The continuous fiber-reinforced plastic A is a known continuous fiber-reinforced plastic in which continuous fibers arranged in one direction are impregnated with a synthetic resin, and a continuous fiber-reinforced plastic in which continuous fibers woven in a fabric-like structure are impregnated with a synthetic resin. Any one of these continuous fiber-reinforced plastics can be used. In this embodiment, the continuous fiber-reinforced plastics A are plastics reinforced with unidirectional carbon fibers in which continuous fibers aligned in one direction are bonded together by a synthetic resin. Furthermore, the carbon fibers used in the randomly distributed fiber-reinforced plastic B in this embodiment are cut to a length of up to approximately 25 mm.

[0030] Materials with comparable thermal characteristics are used as matrices (base materials) in the continuous fiber-reinforced plastics A and the random fiber-reinforced plastics B. These materials can be thermoplastic resins (e.g., polyamide resins (PA6, PA66) and polypropylene resins) or thermosetting resins (e.g., epoxy resins). If the connecting strut 1 is produced using a manufacturing process for processing fiber-reinforced plastics or an SMC (Sheet Molding Compound) process, the thermosetting resin is used. If the connecting strut 1 is produced by injection molding, the thermoplastic resin is used.

[0031] The connecting strut 1 is arranged between the vehicle body element and the wheel bearing element. This results in a tensile and a compressive load acting primarily in an axial direction along the rod section 10, i.e., along an axis L1 that connects a center point Oa of the bearing eye 21 of the coupling section 20a and a center point Ob of the bearing eye 21 of the coupling section 20b. The centers Oa and Ob of the bearing eyes 21 coincide with the centers of opening holes 51a of the cylindrical tubes 51 of the elastic sleeves 50.

[0032] In a product made from carbon fiber reinforced plastic (CFRP), there is a difference between the strength under tensile load (tensile strength) and the strength under compressive load (compressive strength), depending on the arrangement of the carbon fibers (reinforcing fibers). For example, plastic B, reinforced with randomly distributed fibers, exhibits low tensile strength and high compressive strength. In contrast, plastic A, reinforced with continuous fibers, exhibits significantly high tensile strength and low compressive strength in the direction of the continuous fibers.

[0033] In the connecting strut 1, a load acts mainly on the coupling section 20 by introducing stress in the direction of the axis line L1. In the coupling section 20, a section with the lowest tensile strength (designated as the "weakest section W") is a section W of the Fig. 1. The weakest section W is positioned in a region around a position X located in a plane Fa(Fb) perpendicular to the axis line L1 and passing through the center point Oa(Ob) of the bearing eye 21. Meanwhile, when pressure occurs in the direction of the axis line L1, the load acts primarily on the entire rod section 10.

[0034] In light of the above, with reference to rod section 10, the randomly distributed fiber-reinforced plastic B is used as a fiber-reinforced plastic over the entire longitudinal direction of the rod. That is to say, the entire rod section 10 is made of randomly distributed fiber-reinforced plastic B.

[0035] Meanwhile, with reference to the coupling section 20, the continuous fiber-reinforced plastic A is used over an area on a distal end side of the connecting strut 1, which extends continuously around at least half the circumference about a central axis L2 through the center point Oa(Ob) of the bearing eye 21, the area encompassing position X (there are two opposing positions X), and the randomly distributed fiber-reinforced plastic B is used in an area on the side of the rod section 10 relative to the area, which extends continuously around at least half the circumference.This means that the coupling section 20 in the area on the distal end side of the connecting strut 1 is made of the continuous fiber-reinforced plastic A, which extends continuously around at least half the circumference around the central axis L2 of the bearing eye 21, wherein the area encompassing positions X intersects the plane Fa(Fb) which is perpendicular to the axis line L1 connecting the centers Oa and Ob of the bearing eyes 21, and passes through the center Oa(Ob) of the bearing eye 21, and the area of ​​the coupling section 20 on the side of the rod section 10 opposite the area extending continuously around at least half the circumference is made of the randomly distributed fiber-reinforced plastic B.

[0036] The fiber-reinforced plastic A contains the fibers oriented circumferentially around the bearing eye 21. In this case, in the fiber-reinforced plastic A, where the fibers are oriented in one direction, the fibers are arranged circumferentially around the bearing eye 21 such that they are parallel to a plane perpendicular to the central axis L2 of the bearing eye 21. Furthermore, in the fiber-reinforced plastic A, where the fibers are woven in a fabric-like structure, it is only necessary that the fibers be arranged circumferentially around the bearing eye 21 when viewed from the top, looking down from the direction of the central axis L2 of the bearing eye 21.

[0037] In the Fig. In the coupling section 20 shown in Figure 2A, a semi-circular circumferential region R1, extending continuously between positions X, can be made of the plastic A reinforced with continuous fibers, and as shown in Figure 2A. Fig. Figure 2B illustrates that a C-shaped arc region R2, which is longer in the circumferential direction than the semi-circular circumferential region R1, can be made from the plastic A reinforced with continuous fibers.

[0038] Furthermore, in coupling section 20, as in Fig. Figure 2C shows an annular region R3, which is longer in the circumferential direction than the C-shaped arc region R2, made of the continuous fiber-reinforced plastic A. The annular region R3 can extend to the side of the rod section 10 up to a boundary region where the coupling section 20 and the rod section 10 are connected. In the boundary region, it is desirable that the continuous fiber-reinforced plastic A and the randomly distributed fiber-reinforced plastic B are designed to overlap each other in the thickness direction of the rod.

[0039] Furthermore, coupling section 20 can be used as in Fig. Figure 3 illustrates that the continuous fiber-reinforced plastic A can be manufactured from only a portion of its thickness in a radial direction (radial direction of the bearing eye 21). In this example, only a portion of the C-shaped arc region R2 on a radially inner side is manufactured from the continuous fiber-reinforced plastic A, but only a portion of the C-shaped arc region R2 on a radially outer side can be manufactured from the continuous fiber-reinforced plastic A. Furthermore, only a portion of the half-circumference arc region R1 on either the radially inner or radially outer side can be manufactured from the continuous fiber-reinforced plastic A. Additionally, only a portion of the annular region R3 on either the radially inner or radially outer side can be manufactured from the continuous fiber-reinforced plastic A.

[0040] The areas of the in the Fig. 2A to 2C and Fig. The 3 shown plastics A, reinforced with continuous fibers, have a common cross-section at each position in the axial direction of the coupling section 20 (axial direction of the bearing eye 21).

[0041] Furthermore, in both coupling sections 20a and 20b, it is not necessary for the areas in which the plastic A reinforced with continuous fibers is formed to be identical, and these areas can be defined independently of each other.

[0042] The connecting strut described above can be manufactured seamlessly, for example, using the SMC manufacturing process or injection molding. Fig. 5 and Fig. Figure 6 illustrates an example of the SMC manufacturing process. The connecting strut is formed using layers that are base materials for obtaining randomly distributed carbon fiber reinforced plastics (commonly referred to as SMC materials and hereinafter referred to as "SMC materials") and layers that are base materials for obtaining unidirectional carbon fiber reinforced plastics (commonly referred to as UD prepregs and hereinafter referred to as "UD prepregs"). "UD" is an abbreviation for "unidirectional".

[0043] SMC material is a layered material in a partially cured state, in which randomly oriented carbon fibers (for example, carbon fibers cut to a length of approximately 25 mm or less) are mixed into a thermoplastic resin. UD prepreg is a layered material in a partially cured state, in which carbon fibers oriented in one direction are impregnated with a thermosetting resin.

[0044] As in Fig. Figure 5 shows a recessed section 110, designed to form the underside (one side in the axial direction of the coupling section) of the connecting strut 1, formed or inserted in a lower mold (metal mold) 100. The recessed section 110 comprises a rod section generation area 111 and coupling section generation areas 112a and 112b. The rod section generation area 111 is located in the center and is designed to generate the underside of the rod section 10. The coupling section generation areas 112a and 112b are arranged on both sides of the rod section generation area 111, extending through the rod section generation area 111, and are designed to generate the lower parts of the coupling sections 20.

[0045] As in Fig. Figure 6 illustrates how SMC materials 200 are arranged vertically overlapping in the rod section generation area 111 such that they are parallel to a longitudinal direction of the rod section 10. The number of overlapping SMC materials 200 and their respective layer shapes are determined to match the shape of the rod section 10. Furthermore, the elastic sleeves 50, each comprising several UD prepregs 300 wound overlapping around an outer circumference (a cylindrical surface), are arranged in the coupling section generation areas 112a and 112b. In this case, the direction of each of the UD prepregs 300 is determined such that its continuous fibers are aligned in the circumferential direction of the elastic sleeve 50 (aligned in the circumferential direction of the bearing eye 21 so that they are parallel to a plane perpendicular to the central axis L2 of the bearing eye 21).This example corresponds to the case where the ring-shaped region R3 is as in . Fig. 2C is made from the continuous fiber reinforced plastic A, and the UD prepregs 300 are attached so that they are wrapped around the entire circumference of the elastic sleeve 50.

[0046] After the SMC materials 100 and the elastic sleeves 50, each having the UD prepregs 300 wrapped around them, are inserted into the lower mold 100 as described above, an upper mold (not shown) (a metallic casting mold) is lowered (a mold having a recessed section designed to produce a top surface of the connecting strut 1 in the same way as in the lower mold 100), and the SMC materials 200 and the elastic sleeves 50 are pressurized and heated simultaneously with the upper and lower molds. During this process, suction is also performed.

[0047] Consequently, the SMC materials, the UD prepregs 300 and the elastic sleeves 50 are seamlessly integrated to form the connecting strut 1.

[0048] Furthermore, the UD prepregs 300 are, for example, provisionally attached to a circumferential region of an outer circumferential surface of the elastic sleeve 50, which corresponds to the semicircular arc on circumferential region R1 or the C-shaped arc region R2, and the SMC materials 200 are provisionally attached to another circumferential region if the semicircular arc on circumferential region R1 and the C-shaped arc on region R2 as in the Fig. 2A and Fig. Figure 2B illustrates that the components are made from the continuous fiber-reinforced plastic A. It is then only necessary to arrange the elastic sleeve 50 with the SMC materials 200 and the UD prepregs 300, which are temporarily attached to it, in each of the coupling section formation areas 112a and 112b. Similarly, the UD prepregs 300 are temporarily fixed to a section of the elastic sleeve 50 where the continuous fiber-reinforced plastic A is to be formed, if a portion of the thickness of the coupling section 20 in the radial direction is made of continuous fiber-reinforced plastic A as shown in Figure 2B. Fig. Figure 3 illustrates this, and the SMC materials 200 are temporarily fixed to another section. Then it is only necessary that the elastic sleeve 50 with the SMC materials 200 and the UD prepregs 300, which are temporarily attached to it, is arranged in each of the coupling section generation areas 112a and 112b.

[0049] Furthermore, in this embodiment, the UD prepregs 300 are used as the base material to obtain the fiber-reinforced plastic, but instead of the UD prepregs 300, a layer obtained by impregnating a carbon fiber woven fabric with a synthetic resin can be used (generally and hereinafter referred to as "fabric prepreg"). In this case, it is only necessary that several fabric prepregs, overlapping each other in the same manner as in the UD prepregs 300, are arranged in each of the coupling section generating areas 112a and 112b in a state in which they are wound onto the outer circumferential surface of the elastic sleeve 50 by at least half a circumference. Consequently, the continuous carbon fibers in the fabric prepregs are arranged in the circumferential direction of the bearing eye 21 when viewed from the top view from the direction of the central axis L2 of the bearing eye 21.

[0050] In the connecting strut 1 according to the embodiment described above, the two coupling sections 20 are each made of the fiber-reinforced plastic A, in which the fibers are oriented circumferentially around the bearing eye 21 over the area on the distal end of the connecting strut 1. This area extends continuously around the central axis of the bearing eye 21 for at least half a circumference. This area includes the position that intersects the plane perpendicular to the straight line connecting the centers of the bearing eyes 21 and passing through the center of the bearing eye 21. Thus, the weakest section with the lowest tensile strength is made of the fiber-reinforced plastic A, and consequently, the weight can be reduced while maintaining the required strength even in the weakest section.

[0051] Furthermore, the cost of the fiber-reinforced plastic A is higher than that of the fiber-reinforced plastic B. Therefore, the required tensile strength can be maintained at low cost with the connecting strut 1, in which the fiber-reinforced plastic A is used as in the Fig. 2A and Fig. Figure 2B illustrates the arc-shaped arrangement around the central axis of the bearing eye 21.

[0052] Furthermore, in the connecting strut 1, in which the area made of continuous fiber-reinforced plastic A has a ring shape that corresponds to the central axis of the bearing eye 21 as in Fig. Figure 2C illustrates a composite surface on which the continuous fiber-reinforced plastic A and the randomly distributed fiber-reinforced plastic B are bonded together, not in the circumferential direction around the central axis of the bearing eye 21, and consequently the fatigue strength can be improved. In addition, the manufacturing process can be simplified.

[0053] Furthermore, as in Fig. Figure 3 illustrates how the required tensile strength can be obtained at low cost if the connecting strut 1, in which part of the thickness in the radial direction of the coupling section 20 (the radial direction of the bearing eye 21) is made of the continuous fiber reinforced plastic A, and the remaining part of the thickness in the radial direction is made of the randomly distributed fiber reinforced plastic B, is made by setting the thickness of the continuous fiber reinforced plastic A to suit the required strength.

[0054] Furthermore, the connecting strut 1 can be seamlessly formed, and consequently the fatigue strength is high even against the application of cyclic fatigue.

[0055] The connecting strut for a vehicle of this embodiment has been described above, but the present invention is not limited to the embodiment described above, and various modifications are possible in areas that do not deviate from the field of the present invention. Reference symbol list 12 Connecting strut 10 rod sections 20 a Coupling section 20 b Coupling section 21 Bearing eye (insertion hole) 50 Coupling element (elastic sleeve) 51 a Opening holes 51 Cylinder tube (metal cylindrical tube) 52 cylindrical rubber-elastic bodies 100 metal molds 110 recessed section 111 Bar section production area 112 a Coupling section generation area 112 b Coupling section generation area 200 SMC materials 300 UD prepregs A plastic reinforced with continuous fibers B. Plastic reinforced with randomly distributed fibers Fa, Fb Level L 1 straight line (connecting the centers of the bearing eyes) L 2 Central axis through the center of the bearing eye The center of the camp eye Whether center of the storage eye R 1 semi-circular circumferential area R 2 C-shaped arc area R 3 ring-shaped area W weakest section X position in plane Fa perpendicular to the axis line and through Oa

Claims

[1] Connecting strut (1) for a vehicle with: a rod section (10) which is formed into a solid rod shape; and two coupling sections (20a, 20b), each having a ring shape, wherein the two coupling sections (20a, 20b) are arranged at both ends of the rod section (10) and each have a bearing eye (21) into which a coupling element (50) can be inserted, which can be coupled to either a vehicle body element or a wheel bearing element, wherein the connecting strut (1) is entirely made of a fiber-reinforced plastic, the two coupling sections (20a, 20b) each comprise a plastic (A) reinforced with continuous fibers, in which the continuous fibers are aligned along a circumferential direction of the bearing eye (21) over a region at a distal end side of the connecting strut (1) which extends continuously around at least half a circumference (R1) about a central axis (L2) of the bearing eye (21), wherein the region includes a position which lies in a plane (Fa, Fb) which is perpendicular to a straight line (L1) which connects the centers (Oa, Ob) of the bearing eyes (21), wherein the plane passes through the center (Oa, Ob) of the bearing eye (21), characterized by, that the fiber-reinforced plastic comprises the continuous fiber-reinforced plastic (A) in which continuous fibers are bonded together by a synthetic resin, and a randomly distributed fiber-reinforced plastic (B) in which non-continuous fibers are bonded together by a synthetic resin in random orientations, and the rod section (10) comprises the plastic (B) reinforced with randomly distributed fibers. [2] Connecting strut (1) for a vehicle according to claim 1, wherein at least one of the two coupling sections (20a, 20b) comprises the following: a region (R1; R2) comprising the continuous fiber-reinforced plastic (A), wherein the region (R1; R2) is shaped as an arc around the central axis (L2) of the bearing eye (21); and an area on the side of the rod section (10) opposite the area (R1; R2) which is shaped as an arc, wherein the area on the side of the rod section (10) comprises the plastic (B) reinforced with randomly distributed fibers. [3] Connecting strut (1) for a vehicle according to claim 1, wherein at least one of the two coupling sections (20a, 20b) comprises a region (R3) comprising the plastic (A) reinforced with continuous fibers, wherein the region (R3) surrounds the central axis (L2) of the bearing eye (21) as a ring. [4] Connecting strut (1) for a vehicle according to one of claims 1 to 3, wherein at least one of the two coupling sections (20a, 20b) comprises the plastic (A) reinforced with continuous fibers in a part of the thickness in a radial direction, and comprises the plastic (B) reinforced with randomly distributed fibers in a remaining part of the thickness in the radial direction. [5] Connecting strut (1) for a vehicle according to any one of claims 1 to 4, wherein the continuous fibers and the non-continuous fibers comprise carbon fibers.

Images