JP2015113359A - Manufacturing method of bar-like component, and bar-like component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a bar-like component, and the bar-like component in which a manufacturing cost can be reduced while positioning accuracy of a pipe made of carbon fiber-reinforced resin and a metal component is improved in the case of constituting a bar-like component by connecting the pipe and the metal component.SOLUTION: A bar-like component 22 has a pipe 10, and body parts 20 and extension parts 21 which are arrayed in an axial direction X of the pipe 10, and the extension parts 21 include metal components 17, 18 connected to the pipe 10 from the axial direction X. A manufacturing method of the bar-like component 22 includes: a process of winding a prepreg sheet 26 impregnated with resin 28 to a core material, which is constituted by connecting a mandrel to the extension part 21 having an outer peripheral surface 21A to which surface roughening is applied, in the axial direction X; a process of forming the pipe 10 which is externally fixed to the outer peripheral surface 21A by burning and hardening the prepreg sheet 26 wound to the core material; and a process of removing the mandrel from the pipe 10.

Description

  The present invention relates to a method for manufacturing a bar-shaped part that constitutes, for example, a steering apparatus for a vehicle and the bar-shaped part.

  In the propeller shaft of Patent Document 1 below, a thin metal ring that is substantially equal to the inner diameter of the main body cylinder is attached to the inside of the end of the FRP (fiber reinforced plastic) main body cylinder. It is manufactured by press fitting a metal joint having an outer diameter larger than the inner diameter of the ring. During the press-fitting, the hard particles arranged on the outer peripheral surface of the thin ring bite into the inner surface of the FRP main body cylinder.

  In addition, as an application example of fiber reinforced plastic, as disclosed in Patent Document 2 below, a roll body of a gravure printing roll in which a FRP cylindrical body is fitted inside a metal cylindrical body via an adhesive layer, and the following patent As in Document 3, a rack obtained by winding a prepreg around a small diameter portion of a core metal and laminating it to form a carbon fiber reinforced plastic outer shell can be mentioned.

Japanese Patent Laid-Open No. 7-91433 JP-A-5-193097 JP 2013-75533 A

  In the propeller shaft of Patent Document 1, since a thin ring exists between the FRP main body cylinder and the joint, the FRP main body cylinder and the joint are positioned so as to be coaxial (also referred to as ensuring the coaxiality). Is difficult. Furthermore, since the outer peripheral surface of the thin ring bites into the inner surface of the FRP main body cylinder due to the press fitting of the joint to the thin ring, the fibers constituting the fiber reinforced plastic of the main body cylinder may be cut. Therefore, since measures such as processing for preventing the fiber from being cut are necessary, the manufacturing cost of the propeller shaft may increase.

  The present invention has been made under such a background, and in the case where a bar-shaped part is configured by connecting a pipe made of carbon fiber reinforced resin and a metal part, the positioning accuracy between the pipe and the metal part is improved. It aims at providing the manufacturing method of the bar-shaped components which can aim at reduction of manufacturing cost, and the said bar-shaped components, improving.

  The invention according to claim 1 has a pipe (10) made of carbon fiber reinforced resin, a main body (20) aligned in the axial direction (X) of the pipe, and an extension (21) narrower than the main body. A bar-shaped part (22) including a metal part (17, 18) connected to the pipe in the extension, the metal mandrel (24) extending in the axial direction, and the metal A carbon fiber resin (28) is attached to the outer peripheral surface (23A) of the core member (23) formed by connecting the extension portion having the outer peripheral surface (21A) subjected to roughening in the part in the axial direction. ) Prepreg sheet (26) impregnated) and by baking and curing the prepreg sheet wound around the outer peripheral surface of the core, a part (10A, 10B) with respect to the outer peripheral surface of the extension portion There forming a fitted fixed the pipe, characterized in that it comprises a and a step of removing only the mandrel from the pipe out of the core material, a method for manufacturing a bar-shaped part.

The invention according to claim 2 is characterized in that the outer peripheral surface of the extension portion has a taper shape whose diameter increases as the distance from the main body portion increases in the axial direction. Is the method.
The invention according to claim 3 is characterized in that the extension portion protrudes from the outer peripheral surface thereof and includes a protrusion portion (31) for positioning the pipe in the axial direction. It is a manufacturing method of components.

According to a fourth aspect of the present invention, the step of winding the prepreg sheet around the outer peripheral surface of the core includes a step of interposing a thermal adhesive film (30) between the prepreg sheet and the outer peripheral surface of the extension portion. It is a manufacturing method of the bar-shaped component in any one of Claims 1-3 characterized by these.
A fifth aspect of the present invention is a bar-shaped part manufactured by the manufacturing method according to any one of the first to fourth aspects.

According to a sixth aspect of the present invention, in the bar-shaped component according to the fifth aspect, the bar-shaped part constitutes a rack bar (8) included in a rack-and-pinion type steering device (1). It is a part.
In addition, in the above, the numbers in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

  According to the first aspect of the present invention, the bar-shaped component includes a pipe made of carbon fiber reinforced resin and a metal component having an extension. The core material prepared in the manufacture of the bar-shaped part is an axial connection between a metal mandrel extending in the axial direction of the pipe and an extension having an outer peripheral surface that has been roughened in the metal part. It is constituted by. When manufacturing bar-shaped parts, a prepreg sheet with carbon fiber impregnated with resin is wound around the outer peripheral surface of the core material and then baked and cured, so that part of the extension is fixed to the outer peripheral surface of the extension. A pipe is formed.

Due to the calcination and hardening of the prepreg sheet, the resin that has exuded from the prepreg sheet has entered the recesses on the outer peripheral surface that has been subjected to rough surface processing (concavo-convex processing) at the extension. As a result, the pipe is in close contact with the extension and is firmly fixed.
Thus, in the bar-shaped part, the pipe and the metal part are directly connected without interposing another part between the pipe and the metal part. Therefore, the state where the pipe and the metal part are coaxially arranged can be maintained, and the positioning accuracy between the pipe and the metal part can be improved. In addition, the separate part can be omitted, and when the separate part is provided, a necessary measure for preventing the cutting of the carbon fiber is not required, and thus the manufacturing cost of the entire bar-shaped part can be reduced. .

As a result, the manufacturing cost can be reduced while improving the positioning accuracy between the pipe and the metal part.
When the outer peripheral surface of the extension portion is tapered as in the second aspect of the invention, since the pipe is difficult to be removed from the extension portion, the pipe and the metal part are difficult to disassemble. Improvements can be made.

When the protruding portion of the outer peripheral surface of the extension portion positions the pipe in the axial direction as in the invention described in claim 3, it is difficult for the pipe and the metal part to be disassembled because the pipe is difficult to be removed from the extension portion. The strength of the bar-shaped part can be improved.
When the thermal adhesive film is interposed between the prepreg sheet and the outer peripheral surface of the extension portion as in the invention described in claim 4, the outer peripheral surface of the extension portion and the pipe are not only the resin of the prepreg sheet but also the thermal adhesive film. Therefore, the extension portion and the pipe can be more firmly fixed.

According to the fifth aspect of the invention, in the bar-shaped part manufactured by the manufacturing method according to any one of the first to fourth aspects, the manufacturing cost can be reduced while improving the positioning accuracy between the pipe and the metal part. Can be planned.
As in the sixth aspect of the invention, the bar-like component may constitute a rack bar included in a rack and pinion type steering device.

FIG. 1 is a schematic front view of a steering apparatus 1 including a bar-like component 22 according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the manufacturing process of the bar-shaped component 22. FIG. 3 is a schematic cross-sectional view showing the next step of FIG. FIG. 4 is a schematic cross-sectional view showing the next step of FIG. FIG. 5 is an enlarged view of a portion surrounded by a two-dot chain line in FIG. FIG. 6 is a diagram in which the first modification of the present invention is applied to FIG. FIG. 7 is a cross-sectional view of a portion where the second metal part 18 and the pipe 10 of the second modification are connected. FIG. 8 is a diagram in which the third modification is applied to FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic front view of a steering apparatus 1 including a bar-like component 22 according to an embodiment of the present invention.
Referring to FIG. 1, steering device 1 mainly includes a steering member 2, a steering shaft 3, an intermediate shaft 5, a pinion shaft 7, a rack bar 8, and a housing 9.

  For example, a steering wheel can be used as the steering member 2. One end of a steering shaft 3 is connected to the steering member 2. The other end of the steering shaft 3 and one end of the intermediate shaft 5 are connected by a universal joint 4. Further, the other end of the intermediate shaft 5 and one end of the pinion shaft 7 are connected by a universal joint 6. The steering shaft 3, the intermediate shaft 5, and the pinion shaft 7 do not have to be on the same straight line.

Pinion teeth 14 are integrally provided on the outer peripheral surface of the other end of the pinion shaft 7. The rack bar 8 has a substantially cylindrical shape extending in the width direction of the vehicle (the left-right direction in FIG. 1). Here, the direction in which the rack bar 8 extends is defined as the axial direction X. The axial direction X is the same as the vehicle width direction (left-right direction in FIG. 1).
Rack teeth 15 that mesh with the pinion teeth 14 are formed at one place on the circumference of the outer peripheral surface of the rack bar 8. The pinion teeth 14 of the pinion shaft 7 and the rack teeth 15 of the rack bar 8 mesh with each other to constitute a rack-and-pinion type steering mechanism A.

The rack bar 8 is accommodated in the housing 9. The housing 9 is a substantially cylindrical body fixed to the vehicle body. Both end portions of the rack bar 8 protrude to both sides of the housing 9, and tie rods 12 are coupled to the respective end portions via joints 11. Each tie rod 12 is connected to a corresponding steered wheel 13 via a corresponding knuckle arm (not shown).
When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is converted into a linear motion of the rack bar 8 along the axial direction X by the pinion teeth 14 and the rack teeth 15. Thereby, the turning of the steered wheel 13 is achieved. Thus, the rack bar 8 can steer the steered wheels 13 by moving in the axial direction X in accordance with the steering of the steering member 2.

The rack bar 8 includes one end (the left end in the axial direction X in FIG. 1) 8A and the other end (the right end in the axial direction X in FIG. 1) 8B. The rack bar 8 mainly includes a pipe 10 and two metal parts, a first metal part 17 and a second metal part 18. Rack teeth 15 are provided on the second metal component 18.
The pipe 10 is made of carbon fiber reinforced resin and has a substantially cylindrical shape extending in the axial direction X. The pipe 10 is provided, for example, on the rack bar 8 on the one end 8 </ b> A side with respect to the rack teeth 15, and is disposed between the first metal component 17 and the second metal component 18 in the axial direction X. One end of the pipe 10 (the left end in the axial direction X in FIG. 1) is marked with “10A”, and the other end (the right end in the axial direction X in FIG. 1) is marked with “10B”. The reference numeral “10C” is attached to the inner peripheral surface of the pipe 10.

The first metal component 17 is adjacent to the joint 11 on the one end 8A side as one end 8A of the rack bar 8. The first metal component 17 is connected to the one end 10 </ b> A of the pipe 10 from the one end 8 </ b> A side of the rack bar 8.
The first metal component 17 integrally has a main body portion 20 and an extension portion 21 arranged in the axial direction X. The main body 20 has a cylindrical shape having a central axis extending in the axial direction X. The extension 21 is provided on the first metal component 17 on the other end 8B side of the rack bar 8 with respect to the main body 20. The extension portion 21 has a cylindrical shape extending in the axial direction X from the main body portion 20 toward the other end portion 8B side. The extension 21 is narrower than the main body 20 and is arranged coaxially with the main body 20. The first metal component 17 is formed with an insertion hole 17A extending in the axial direction X. The insertion hole 17A penetrates both the main body 20 and the extension 21 in the axial direction X through the central axes of the main body 20 and the extension 21.

  The second metal component 18 is adjacent to the joint 11 on the other end 8B side as the other end 8B of the rack bar 8. The second metal component 18 is made of, for example, a carbon steel such as S45C that has been quenched to prevent the rack teeth 15 from being worn. Examples of the quenching process include carburizing quenching and induction quenching. The second metal component 18 is connected to the other end 10 </ b> B of the pipe 10 from the other end 8 </ b> B side of the rack bar 8. Similar to the first metal component 17, the second metal component 18 integrally includes the main body portion 20 and the extension portion 21 described above. However, the main body portion 20 and the extension portion 21 of the second metal component 18 may differ from the main body portion 20 and the extension portion 21 of the first metal component 17 in dimensions (diameter and length in the axial direction X). Good.

  The main body portion 20 of the second metal component 18 has a cylindrical shape having a central axis extending in the axial direction X. Rack teeth 15 are provided on the main body 20. The extension portion 21 of the second metal component 18 is provided on the end portion 8 </ b> A side of the rack bar 8 with respect to the main body portion 20 in the second metal component 18. The extension portion 21 has a cylindrical shape extending in the axial direction X from the main body portion 20 toward the one end portion 8A side. However, the second metal part 18 does not have an insertion hole corresponding to the insertion hole 17A of the first metal part 17, and is solid.

  The extension portion 21 of the first metal component 17 is fitted from the axial direction X (left side in FIG. 1) into the hollow portion of the one end portion 10A of the pipe 10. Further, the extension portion 21 of the second metal part 18 is fitted into the hollow portion of the other end portion 10B of the pipe 10 from the axial direction X (right side in FIG. 1). Thereby, each of the 1st metal component 17 and the 2nd metal component 18 is connected with the end part (the one end part 10A or the other end part 10B) of the pipe 10 from the axial direction X in the extension part 21.

  The connected pipe 10, the first metal part 17, and the second metal part 18 are integrated to form a bar-shaped part 22 that extends in the axial direction X as a whole. This bar-shaped component 22 constitutes the rack bar 8. Since a part of the rack bar 8 is constituted by the pipe 10 made of carbon fiber reinforced resin, the weight can be significantly reduced as compared with the case where the whole rack bar 8 is constituted by metal.

Next, a method for manufacturing such a bar-shaped part 22 will be described.
FIG. 2 is a schematic cross-sectional view showing the manufacturing process of the bar-shaped component 22. The posture of each member in FIG. 2 is the same as that in FIG. 1 (the same applies to FIGS. 3 to 8 described later).
With reference to FIG. 2, a core material 23 is prepared as an initial stage of manufacturing the bar-shaped part 22. The core material 23 is a member necessary for forming the cylindrical pipe 10. The core member 23 is configured by connecting the mandrel 24 and the extended portions 21 of the first metal component 17 and the second metal component 18 in the axial direction X.

The mandrel 24 is made of metal and has a cylindrical shape extending in the axial direction X.
The outer peripheral surface 21A of each extension portion 21 of the first metal component 17 and the second metal component 18 is roughened in advance. Therefore, the outer peripheral surface 21 </ b> A has a large number of uneven portions 27. Examples of the rough surface processing here include iris knurl processing, key groove processing, spline processing, shot blast processing, acid etching, laser etching, and the like.

Further, since the second metal part 18 has been subjected to the above-described quenching process, the extension portion 21 of the second metal part 18 has improved resistance to bending stress, and the outer peripheral surface 21A of the extension portion 21 is improved. The toughness is improved in the portion subjected to the rough surface processing as compared with the material not subjected to the quenching processing. The first metal component 17 may also be quenched.
In FIG. 2, as an initial stage of the manufacturing process of the bar-shaped part 22, the core member 23 is prepared by connecting the mandrel 24 and the extended portions 21 of the first metal part 17 and the second metal part 18 in the axial direction X. Is done. Specifically, the first metal component 17 and the second metal component 18 are arranged apart from each other in the axial direction X with the extension portions 21 facing each other, and then the insertion hole 17 </ b> A of the first metal component 17. The mandrel 24 is inserted through the cable. In the mandrel 24 after insertion, part of the mandrel 24 remains in the insertion hole 17A, and the other part extends from the insertion hole 17A and extends to the second metal part 18. In the mandrel 24, the end portion 24 </ b> A on the second metal component 18 side abuts against the extension portion 21 of the second metal component 18 from the axial direction X (first metal component 17 side). Thereby, the mandrel 24 is constructed between the first metal part 17 and the second metal part 18, and the first metal part 17, the second metal part 18 and the mandrel 24 are coaxially connected, The core material 23 is completed. Of the second metal part 18 and the mandrel 24, a convex part is provided on one side, a concave part is provided on the other side, and the convex part fits into the concave part, whereby the second metal part 18 and the mandrel 24 are coaxial. In place of the concave and convex portions, a dedicated jig for positioning may be used.

The completed outer peripheral surface 23 </ b> A of the core member 23 includes an outer peripheral surface 21 </ b> A of each extension portion 21 and an outer peripheral surface 24 </ b> B of the mandrel 24 that protrudes from the insertion hole 17 </ b> A to the second metal component 18 side.
Since the first metal part 17, the second metal part 18, and the mandrel 24 are connected coaxially, the central axis C 1 of each extension 21 of the first metal part 17 and the second metal part 18 and the mandrel 24 The central axis C2 extends in the axial direction X in agreement.

FIG. 3 is a schematic cross-sectional view showing the next step of FIG.
With reference to FIG. 3, the prepreg sheet 26 used as the material of the pipe is prepared. The prepreg sheet 26 is, for example, a sheet shape in which a large number of carbon fibers (not shown) aligned in one direction (Uni-Direction) are impregnated with a resin 28. For the prepreg sheet 26, any carbon fiber typified by “Torayca” (registered trademark) T300 and “Torayca” (registered trademark) T700 can be used. The resin 28 may be a thermosetting resin such as an epoxy resin, a polyimide resin, a bismaleimide resin, and an unsaturated polyester resin. Since the rack bar 8 is used in the engine room of the vehicle, the curing temperature of the resin 28 is preferably 130 ° C. or higher.

  In the process shown in FIG. 3, the prepreg sheet 26 is wound around the outer peripheral surface 23 </ b> A of the core member 23 in a single or double manner by, for example, a sheet winding method. In the state after winding, as shown in FIG. 3, the prepreg sheet 26 straddles the mandrel 24 and each extension portion 21. Further, since the prepreg sheet 26 is in close contact with the outer peripheral surface 24B of the mandrel 24 and the outer peripheral surface 21A of each extension portion 21 and surrounds the core member 23, the prepreg sheet 26 has a substantially cylindrical shape as a whole.

  Next, the prepreg sheet 26 wound around the outer peripheral surface 23 </ b> A of the core material 23 is baked and cured. By the baking and curing here, the shape of the prepreg sheet 26 is fixed in a substantially cylindrical shape when wound around the outer peripheral surface 23 </ b> A of the core member 23. Thereafter, the prepreg sheet 26 becomes the pipe 10 after cooling at room temperature. That is, the pipe 10 is formed by baking and curing the prepreg sheet 26 wound around the outer peripheral surface 23A. In the pipe 10 in this state, a part (end portions 10A and 10B) is externally fitted to the outer peripheral surface 21A of each extension portion 21 (specifically, externally fixed as described later).

The center axis C3 of the pipe 10 coincides with the center axis C1 of each extension 21 and the center axis C2 of the mandrel 24, and the pipe 10 is arranged coaxially with each extension 21 and mandrel 24.
The prepreg sheet 26 is wound around the outer peripheral surface 23 </ b> A of the core member 23 with a main winding method (so-called helical winding) in which the extending direction of the carbon fibers is directed in the axial direction X. Therefore, in the pipe 10, since the internal carbon fibers are aligned in the axial direction X, the strength in the axial direction X is high.

FIG. 4 is a schematic cross-sectional view showing the next step of FIG.
Next, referring to FIG. 4, only the mandrel 24 of the core material 23 is removed from the pipe 10. Specifically, the entire mandrel 24 is pulled out from the insertion hole 17 </ b> A of the first metal component 17. At this time, the mandrel 24 may be contracted by cooling in order to pull it out smoothly. In that case, the force required to pull out the mandrel 24 from the pipe 10 is reduced.

  In the state where the mandrel 24 is removed, a gap 25 (for example, a gap of about 1 mm to 2 mm at the end in the axial direction X) is provided between each main body 20 and the one end 10A and the other end 10B of the pipe. It is preferable to keep it. For this purpose, in the step of winding the prepreg sheet 26 around the outer peripheral surface 23 </ b> A of the core member 23, the gap 25 may be provided between the main body portion 20 and the prepreg sheet 26 may be wound.

If the gap 25 is provided, it is possible to prevent the end portions 10A and 10B from coming into contact with the main body portions 20 when a bending stress is applied to the pipe 10, and the pipe 10 is destroyed against the bending stress. Strength can be improved.
As described above, the pipe 10 is connected to the first metal component 17 and the second metal component 18 at both end portions 10A and 10B in the axial direction X, and the bar-shaped component 22 is completed.

In this state, the center axis C1 of each extension portion 21 and the center axis C3 of the pipe 10 are kept in agreement with each other, and each extension portion 21 is kept coaxially with the pipe 10.
FIG. 5 is an enlarged view of a portion surrounded by a two-dot chain line in FIG.
Referring to FIG. 5, in the completed bar-shaped part 22, a resin 28 that exudes from the prepreg sheet 26 is interposed between the inner peripheral surface 10 </ b> C of the pipe 10 and the outer peripheral surface 21 </ b> A of each extension portion 21. Yes. In the step of winding the prepreg sheet 26 around the core material 23 and the subsequent baking and curing step (see FIG. 3), the resin 28 is formed in each concave portion 29 in the concave-convex portion 27 formed on the outer peripheral surface 21 </ b> A of each extension portion 21. Enter and harden. In the cured state where the resin 28 has entered the concave portion 29, the convex portion 35 of the concave and convex portion 27 is in close contact with the inner peripheral surface 10C of the pipe 10, but the carbon fiber in the prepreg sheet 26 has There is no contact. Therefore, the end portions 10A and 10B of the pipe 10 are externally fitted and fixed (prevented from coming off) to the outer peripheral surface 21A of the corresponding extension portion 21 in a state where the inner carbon fibers are not cut (FIG. 4). reference). Each extension 21 in this state is positioned so as not to be displaced in the axial direction X with respect to the end portions 10A and 10B of the pipe 10 or in the circumferential direction (see FIG. 4).

  Here, unlike the present embodiment, a comparative example in which the extended portion 21 that has been roughened is not used will be assumed. In the case of the comparative example, in order to screw-fasten the pipe 10 and each of the first metal part 17 and the second metal part 18, it is necessary to provide a threaded portion on the inner peripheral surface 10 </ b> C of the pipe 10. In the comparative example, when the prepreg sheet 26 is wound around the core member 23 by helical winding, the carbon in the prepreg sheet 26 in the innermost layer (most core member 23 side) is provided when the thread portion is provided on the inner peripheral surface 10C of the pipe 10. There is a risk of the fibers being cut. When the carbon fiber is cut, the strength of the pipe 10 is significantly reduced. In order to prevent the carbon fiber from being cut in the comparative example, at least the innermost prepreg sheet 26 is wound around the core member 23 in such a manner that the carbon fiber extends in the circumferential direction of the core member 23 (so-called hoop winding). There is a need.

  On the other hand, in the present embodiment, it is not necessary to provide a threaded portion on the inner peripheral surface 10C of the pipe 10, and the pipe 10 can be created only by helical winding (or by increasing the ratio of helical winding). That is, in this embodiment, compared with the comparative example, the number of windings around the core material 23 (see FIG. 3) of the prepreg sheet 26 can be reduced by the amount that can be created by one type of winding. The strength in the direction X can be increased. That is, it is possible to reduce the weight and improve the strength of the pipe 10 by roughening the extended portion 21. Further, the pipe 10 and the first metal part 17 and the second metal part 18 are directly connected without interposing another part between the pipe 10 and the first metal part 17 and the second metal part 18. Therefore, the pipe 10 and the first metal component 17 and the second metal component 18 can be kept coaxially arranged, and the positioning accuracy between the pipe 10 and the first metal component 17 and the second metal component 18 can be increased. Can be improved. In addition, since the separate part can be omitted, and when the separate part is provided, a necessary measure for preventing the cutting of the carbon fiber is not required, so that the manufacturing cost of the entire bar-shaped part 22 can be reduced. it can.

  Further, when another metal part (metal ring) is interposed between the pipe 10 and each of the first metal part 17 and the second metal part 18, the other part is baked to improve bending resistance. Since it is necessary to perform insert processing and rough surface processing, there is a concern that the manufacturing cost may increase as compared with the present embodiment. Furthermore, if each of the first metal part 17 and the second metal part 18 and another part are screwed together, it takes time for screwing and screw fastening, and the first metal part 17 and the second metal part 18 It becomes increasingly difficult to ensure the coaxiality between each pipe 10.

  Further, since the bar-shaped part 22 is not configured by press-fitting each of the first metal part 17 and the second metal part 18 into the pipe 10, the completed pipe 10, the first metal part 17 and the second metal Almost no extra force is applied to each of the parts 18. Therefore, the center axis C3 of the pipe 10 and the center axes C1 of the first metal part 17 and the second metal part 18 can be kept in agreement. That is, the pipe 10 and the first metal part 17 and the second metal part 18 can be kept coaxially arranged, and the positioning accuracy between the pipe 10 and the first metal part 17 and the second metal part 18 can be increased. Can be improved.

As a result, the manufacturing cost can be reduced while improving the positioning accuracy between the pipe 10 and the first metal component 17 and the second metal component 18.
Next, a first modification of the present invention will be described.
FIG. 6 is a diagram in which the first modification is applied to FIG. In FIG. 6, the same members as those described above are denoted by the same reference numerals, and the description thereof is omitted (the same applies to FIGS. 7 and 8 described later).

With reference to FIG. 6, a thermal adhesive film 30 is provided along the concavo-convex portion 27 on the outer peripheral surface 21 </ b> A of the extension portion 21 in the first modification.
After the core material 23 having the thermal adhesive film 30 attached to the extension portion 21 is prepared, the prepreg sheet 26 is wound around the outer peripheral surface 23A of the core material 23 as described above (see FIG. 3). Thereby, the heat bonding film 30 is interposed between the prepreg sheet 26 and the outer peripheral surface 21A. That is, in the first modified example, the step of winding the prepreg sheet 26 around the outer peripheral surface 23A of the core member 23 includes the step of interposing the thermal adhesive film 30 between the prepreg sheet 26 and the outer peripheral surface 21A. By the step of winding the prepreg sheet 26 around the outer peripheral surface 23 </ b> A of the core material 23, the thermal adhesive film 30 is sandwiched between the outer peripheral surface 21 </ b> A and the prepreg sheet 26 along the radial direction of the core material 23. And glued to. Next, the prepreg sheet 26 is baked and cured, so that the thermal adhesive film 30 is more firmly bonded to the prepreg sheet 26 and the outer peripheral surface 21A. Thereby, the extension part 21 and the pipe 10 can be fixed more firmly. In order to improve the strength, it is desirable that the thickness T of the thermal adhesive film 30 does not exceed the height H (the depth of the concave portion 29) of the convex portion 35 in the concave and convex portion 27. The thermal adhesive film 30 can also exhibit a function of relieving stress generated between the pipe 10 and the first metal component 17 or the second metal component 18.

  As the thermal adhesive film 30, a thermal adhesive film containing an epoxy resin, an acrylic resin, and a polyester resin is applicable. Among these, it is desirable to use the thermal adhesive film 30 containing an epoxy resin. If the thermal adhesive film 30 containing an epoxy resin is used, adhesive strength with the prepreg sheet 26 containing an epoxy resin will become still higher, and heat resistance will also be improved.

FIG. 7 is a cross-sectional view of a portion where the second metal part 18 and the pipe 10 of the second modification are connected.
Referring to FIG. 7, the outer peripheral surface 21 </ b> A of the extension portion 21 of the second modified example has a tapered shape that increases in diameter as the distance from the main body portion 20 increases in the axial direction X. Since the pipe 10 is baked and cured in a state of being wound along the extension portion 21, the inner peripheral surface 10 </ b> C of the pipe 10 is also tapered so as to expand in diameter in the axial direction X. With this configuration, when a force is applied to the pipe 10 in the axial direction X (outside in the axial direction X), the tapered outer peripheral surface 21 </ b> A is the inner periphery of the pipe 10 in the extension portion 21 of the second metal component 18. The surface 10C is caught from the axial direction X (inside in the axial direction X). Therefore, since the pipe 10 is difficult to be removed from the extension portion 21, the pipe 10 and the second metal part 18 are difficult to be disassembled, so that the strength of the bar-shaped part 22 can be improved. In FIG. 7, only the periphery of the second metal part 18 is shown, but of course, the outer peripheral surface 21 </ b> A of the extension 21 of the first metal part 17 is also tapered similarly to the extension 21 of the second metal part 18. It may be a shape. Then, the pipe 10 can be prevented from coming off from both the first metal part 17 and the second metal part 18.

FIG. 8 is a diagram in which the third modification is applied to FIG.
Referring to FIG. 8, the extension portion 21 of the third modified example includes a protruding portion 31 that protrudes from the outer peripheral surface 21 </ b> A and positions the pipe 10 in the axial direction X. The protruding portion 31 of the third modification is formed over the entire circumference of the outer circumferential surface 21 </ b> A at the end portion on the opposite side of the main body portion 20 in the axial direction X of the extension portion 21. The other end 10 </ b> B of the pipe 10 is fitted not only to the protrusion 31, but also to the outer peripheral surface 21 </ b> A of the extension 21 on the main body 20 side of the protrusion 31. Therefore, the protruding portion 31 bites into the inner peripheral surface 10C of the pipe 10 to such an extent that the carbon fiber is not cut, and positions the pipe 10 in the axial direction X. With this configuration, when a force is applied to the pipe 10 in the axial direction X (outside in the axial direction X), the protruding portion 31 of the second metal component 18 is caught on the inner peripheral surface 10 </ b> C of the pipe 10. Therefore, since the pipe 10 is difficult to be removed from the extension portion 21, the pipe 10 and the second metal part 18 are difficult to be disassembled, so that the strength of the bar-shaped part 22 can be improved. In FIG. 8, only the periphery of the second metal component 18 is illustrated, but of course, the extension 21 of the first metal component 17 includes the protruding portion 31 in the same manner as the extension 21 of the second metal component 18. You may go out. Then, the pipe 10 can be prevented from coming off from both the first metal part 17 and the second metal part 18.

The present invention is not limited to the embodiment described above, and various modifications can be made within the scope of the claims.
For example, considering the strength of the second metal part 18 on which the rack teeth 15 are formed, it is desirable to provide the insertion hole 17A in the first metal part 17 as in the above-described embodiment. However, if it is not necessary to consider the strength of the second metal part 18, an insertion hole corresponding to the insertion hole 17A is provided in the second metal part 18 instead of the insertion hole 17A of the first metal part 17. May be. In this case, the mandrel 24 is inserted through the insertion hole of the second metal component 18.

Moreover, the thermobonding film 30 of a 1st modification is applicable also to the bar-shaped components 22 of a 2nd modification and a 3rd modification.
Further, the tapered outer peripheral surface 21 </ b> A of the second modification may be provided only on either the first metal component 17 or the second metal component 18.
Moreover, the protrusion part 31 of a 3rd modification does not need to be provided in the perimeter in the circumferential direction of 21 A of outer peripheral surfaces. Further, the protruding portion 31 may be provided on a portion other than the end portion in the axial direction X on the outer peripheral surface 21 </ b> A of the extension portion 21. Further, the protruding portion 31 may be provided only on either the first metal component 17 or the second metal component 18.

  Further, the bar-shaped component 22 of the above-described embodiment is the rack bar 8, but may be configured as a bar-shaped component other than the rack bar 8 (for example, various shafts, rods, pipe-shaped components).

  DESCRIPTION OF SYMBOLS 1 ... Steering device, 8 ... Rack bar, 10 ... Pipe, 10A ... One end part, 10B ... Other end part, 17 ... 1st metal component, 18 ... 2nd metal component, 20 ... Main-body part, 21 ... Extension part, 21A ... outer peripheral surface, 22 ... bar-shaped part, 23 ... core material, 23A ... outer peripheral surface, 24 ... mandrel, 26 ... prepreg sheet, 28 ... resin, 30 ... thermal bonding film, 31 ... protrusion, X ... axial direction

Claims (6)

A bar-shaped part including a pipe made of carbon fiber reinforced resin, a body part aligned in the axial direction of the pipe, and a metal part connected to the pipe in the extension part, the extension part being thinner than the body part A manufacturing method comprising:
A carbon fiber is formed on the outer peripheral surface of the core member formed by connecting the metal mandrel extending in the axial direction and the extension portion having the outer peripheral surface subjected to the roughening process in the metal part in the axial direction. Winding a prepreg sheet impregnated with resin,
Forming the pipe partially fitted and fixed to the outer peripheral surface of the extension by baking and curing the prepreg sheet wound around the outer peripheral surface of the core; and
Removing only the mandrel of the core from the pipe;
The manufacturing method of bar-shaped components characterized by including these.   The method of manufacturing a bar-shaped part according to claim 1, wherein the outer peripheral surface of the extension portion has a taper shape whose diameter increases as the distance from the main body portion increases in the axial direction.   2. The method of manufacturing a bar-shaped part according to claim 1, wherein the extension part protrudes from an outer peripheral surface thereof and includes a protrusion part for positioning the pipe in the axial direction.   The step of winding the prepreg sheet around the outer peripheral surface of the core member includes a step of interposing a thermal adhesive film between the prepreg sheet and the outer peripheral surface of the extension part. The manufacturing method of the bar-shaped components in any one.   A bar-shaped part manufactured by the manufacturing method according to claim 1.   6. The bar-shaped part according to claim 5, wherein the bar-shaped part constitutes a rack bar included in a rack and pinion type steering device.

Images