JP2003205342A - Method and structure for joining member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for joining a member by which the number of man-hour is reduced by unifying a forming process of a member to be formed and a joint process of the member to a base material, and also to provide a structure for joining the members. <P>SOLUTION: The base material 20 having an engagement part 25 is held in a base material holding die 41. The member to be formed 30 is fitted in the base material 20. A base material holding die 41 is rotationally driven, and the flow forming roller 46 presses the member 30 to carry out the plastic shaping of the member 30. A part of member 30 is engaged with the engagement part 25 of the base material 20 by plastic deformation to join the member 30 to the base material 20. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member joining method and a member joining structure, and more particularly to a member joining method and a member joining structure for plastically forming a member to be formed by flow forming and joining it to a base material.

[0002]

A belt type continuously variable transmission has a primary pulley and a secondary pulley respectively provided on a primary shaft and a secondary shaft arranged in parallel with each other, and a drive belt wound between these pulleys. By changing the pulley groove width of each pulley, the ratio of the effective winding diameter of the drive belt with respect to each pulley is changed to continuously change the speed.

Therefore, as shown in FIG. 8, each pulley, for example, the primary pulley, is capable of moving in the axial direction with respect to the fixed sheave 110 which is rotationally driven via a clutch or the like. The movable sheave 120 has a shaft portion 111 of the fixed sheave 110 and the boss portion 1 of the movable sheave 120 for smoothly variably controlling the pulley groove width H.
21, a plurality of ball grooves 111a each extending in the axial direction,
The fixed sheave 110 and the movable sheave 120 are formed via balls 126 which form 121a and are interposed between opposing ball grooves.
And are connected.

A cylinder member 131, which is a hydraulic actuator member, is fixed to the back surface 122 of the movable sheave 120. The cylinder member 131 is fixed to the fixed sheave 110.
The piston member 135, which is another hydraulic actuator member fixed to the shaft portion 111, constitutes the hydraulic actuator 130, and the shaft portion is controlled by the hydraulic oil supplied to and discharged from the hydraulic actuator 130 under the control of the accelerator opening degree and the like. The pulley sheave width H is variably controlled by the movable sheave 120 moving on the 111.

In the conventional example, the cylinder member 131 is formed by press-molding a metal material with a press machine, and is bolted to the back surface 122 of the movable sheave 120. As a method for connecting the cylinder member 131 to the back surface 122 of the movable sheave 120, various connection methods such as caulking connection, welding connection, press-fitting connection and the like are adopted in addition to the above-described bolt connection.

[0006]

However, in the case of the above-mentioned conventional technique, the forming process of the cylinder member 131 and the connecting process to the movable sheave 120 are separate processes independent of each other. Therefore, for example, a great number of man-hours are required for storage, transportation of the cylinder member 131, and setup setting work in the coupling process. Therefore, there is a problem that the product cost rises.

Further, the movable sheave 120 and the cylinder member 1
It is also conceivable to omit the above-described joining step by integrally molding 31 by carving or forging. However, since the pulley surface of the movable sheave 120 needs to be subjected to heat treatment such as carburizing and tempering, the movable sheave 12
When 0 and the cylinder member 131 are integrally molded and subjected to heat treatment, the heat treatment reaches the cylinder member 131 that does not require heat treatment, and post-processing for correcting heat treatment deformation is required. Also, the material of the integrally molded product is limited to a high-grade material for heat treatment. Therefore, the cost becomes high as a result.

In the above-mentioned prior art, the relationship between the movable sheave 120 and the cylinder member 131 has been described. This is formed by molding another general component, that is, a joining member and joining the joined members. This also applies to parts and has the same problems as the above problems.

The present invention has been made in view of the above points, and an object thereof is to integrate a molding process of a molded member and a bonding process to a base material to reduce the number of steps, and a member bonding method. To provide the structure.

[0010]

In the member joining method according to the invention as set forth in claim 1 for solving the above-mentioned problems, a base material having an engaging portion is held in a base material holding die, and the base material has a member to be molded. , The base material holding die is rotationally driven, and the flow forming roller is pressed against the molding target member to plastically mold the molding target member, and a part of the molding target member is plastically deformed in the engaging portion of the base material. It is characterized in that the member to be molded and the base material are joined by engaging with each other.

According to the present invention, the member to be molded can be plastically molded and bonded to the base material. Therefore, it is possible to integrate the molding process and the joining process, which are separate processes from each other in the past, into one process.
Therefore, the man-hours can be reduced by that amount, and the product cost can be reduced.

Further, before the joining of the members to be molded, the base material can be previously subjected to another treatment such as heat treatment. Therefore, it is possible to easily manufacture a product in which members of different processed materials or members of different materials are combined.

According to a second aspect of the present invention, in the member joining method according to the first aspect of the invention, the plastic forming of the member to be molded is performed by moving the flow forming roller while pressing the member to be molded. And According to the present invention, the flow forming roller is moved while being pressed against the molding target member, so that the molding target member can be molded into a precise and complicated shape.

According to a third aspect of the present invention, in the member joining method according to the first or second aspect, the plastic forming of the members to be formed is a flow forming type and a flow forming type in which the base material holding die is rotationally driven integrally. It is characterized in that it is performed in cooperation with a roller. According to the present invention, the member to be molded can be plastically molded into an arbitrary shape according to the flow forming mold. Therefore, the member to be molded can be plastically molded into various shapes by replacing the flow forming mold.

According to a fourth aspect of the invention, in the member joining method according to the third aspect of the invention, the flow forming mold is formed integrally with the base material holding mold. This invention limits the flow forming type of the invention described in claim 3, and according to this invention,
It is not necessary to provide the flow forming type separately from the base material holding type, the structure of the processing machine for performing the flow forming process can be simplified, and the control thereof can be facilitated.

According to a fifth aspect of the present invention, in the member joining method according to any one of the first to fourth aspects, the base material is
A movable sheave of a belt type continuously variable transmission pulley having a fixed sheave provided on a shaft and a movable sheave, the width of which is variably controlled, wherein a molded member is provided on the back surface of the movable sheave and is movable. A hydraulic actuator member for variably controlling a sheave, wherein an engaging portion is formed on a back surface of the movable sheave.

According to the present invention, the hydraulic actuator member can be plastically formed and coupled to the movable sheave. Therefore, the molding process and the coupling process can be integrated into one process, and the number of steps for assembling the pulley of the belt type continuously variable transmission can be reduced by that much, and the product cost can be reduced. Further, before forming and joining the hydraulic actuator member, the pulley surface of the movable sheave can be preliminarily subjected to heat treatment such as carburizing and quenching, so that the pulley can be easily manufactured and the manufacturing cost can be reduced.

According to a sixth aspect of the present invention, in the member joining method according to any one of the first to fifth aspects, the engaging portion is provided with an annular groove that is continuously formed in a circumferential shape. And The present invention limits the shape of the engaging portion. According to the present invention, a part of the member to be molded can be plastically deformed along the annular groove. Therefore, the member to be molded can be bonded to the movable sheave more easily and uniformly.

According to a seventh aspect of the invention, in the member joining method according to the sixth aspect, the annular groove has a dovetail groove cross-sectional shape in which the pair of groove vertical wall surfaces are separated from each other as the annular groove moves to the groove bottom surface. It is characterized by In the present invention, the shape of the annular groove is limited, and by forming the dovetail groove cross-sectional shape, the member to be molded can be more firmly joined to the movable sheave.

According to an eighth aspect of the present invention, in the member connecting method according to any one of the first to seventh aspects, the engaging portion has a predetermined diameter and a predetermined depth and is recessed at predetermined intervals in the circumferential direction. It is characterized in that it is provided with a detent hole.

The present invention limits the shape of the engaging portion. According to this invention, a part of the member to be molded is engaged with the detent hole by plastic deformation. Therefore, the relative rotational movement with respect to the base material can be restricted.

In the member connecting structure according to the ninth aspect of the present invention, the molded member is fitted to the base material having the engaging portion held by the base material holding die, and the base material holding die is rotationally driven, The flow forming roller is pressed against the member to be molded to plastically mold the member to be molded, and a part of the member to be molded is engaged with the engaging portion by plastic deformation to couple the member to be molded with the base material. To do.

According to the present invention, it is possible to perform the plastic forming of the member to be formed and the joining to the base material. Therefore, it is possible to integrate the molding process and the joining process, which are separate processes from each other in the past, into one process.
Therefore, the man-hours can be reduced by that amount, and the product cost can be reduced. Further, before the joining of the members to be molded, the base material can be previously subjected to another treatment such as heat treatment. Therefore, it is possible to easily manufacture a product in which members of different processed materials or members of different materials are combined.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below by taking as an example a case where a base material is a movable sheave of a belt type continuously variable transmission and a member to be molded is a cylinder member of a hydraulic actuator member. .

(First Embodiment) In FIGS. 1 and 2, a cylinder member 30 is molded and a cylinder member 3 is formed.
It is explanatory drawing which shows notionally the method of couple | bonding 0 with the movable sheave 20. 3 is a diagram for explaining the movable sheave 20, FIG. 3 (A) is a plan view showing the movable sheave 20 from the rear surface 22 side, and FIG. 3 (B) is A- of FIG. 3 (A). FIG. 3C is a cross-sectional view taken along line A in the direction of the arrow, and FIG. 3C is a view taken along the line BB of FIG.

The movable sheave 20, which is the base material, has a pulley portion 21 having a flat rear surface 22 and a tapered pulley surface 23.
And a cylindrical boss portion 24 extending in the axial direction from the back surface 22 of the pulley portion 21. The pulley surface 23 of the pulley portion 21 is preliminarily subjected to heat treatment such as carburizing and quenching, and the rear surface 22 of the movable sheave 20 has a structure shown in FIG.
As shown in (A), an annular groove 25 and a detent hole 26 are formed in advance as an engaging portion with which a part of the cylinder member 30 is engaged by plastic deformation.

The annular groove 25 has such a shape that the cylinder member 30 and the movable sheave 20 are integrally coupled in the axial direction by partly engaging the cylinder member 30 by plastic deformation. In the form, the movable sheave 20 is circumferentially continuous around the center of rotation, and the cross section thereof has a pair of groove wall surfaces 25B separated from each other as the groove moves from the back surface 22 to the groove bottom surface 25A, as shown in FIG. 3B. It has a dovetail groove cross-section.

The rotation preventing hole 26 is formed by a part of the cylinder member 30 being engaged by plastic deformation.
The movable sheave 20 and the movable sheave 20 are integrally and rotatably coupled to each other. In the present embodiment, as shown in FIG. 3C, the boss portion 24 has a constant diameter and a predetermined depth. Annular groove 2
It is recessed at four positions at a constant interval in the circumferential direction at a position between No. 5 and 5.

The cylinder member 30 connected to the movable sheave 20 is made of a metallic material and has a central hole 31 through which the boss portion 24 of the movable sheave 20 is inserted before molding, as shown in FIG. It has a disc shape having a predetermined thickness.

The flow forming machine 40 includes a base material holding die 41 for holding the movable sheave 20, and a cylinder member 3.
Flow forming mold 4 for molding 0 into a predetermined shape
2 and a flow forming roller 43 that plastically deforms the cylinder member 30.

The base material holding die 41 is rotatably provided by a rotation driving means (not shown), and is configured to be coaxially rotatable while holding the boss hole of the movable sheave 20 and the pulley surface 23 of the pulley portion 21. have.

The flow forming die 42 moves up and down above the base material holding die 41, and at the same time, the base material holding die 41.
And a central hole 42A that is rotatably provided integrally with the movable sheave 20 and has an inner diameter that can fit into the boss portion 24 of the movable sheave 20,
It has a thick-walled cylindrical shape having an outer peripheral surface 42 </ b> B for forming the cylinder member 30, which is arranged so as to stand at a predetermined height from the back surface 22 of the movable sheave 20 in the lowered state.

In the present embodiment, the flow forming mold 42 also has a function as a fixing means for sandwiching the movable sheave 20 and the cylinder member 30 with the base material holding mold 41 and integrally rotatably fixing them. is doing. For example, on the lower surface 42C of the flow forming mold 42, as shown in FIG. 4, a concave portion 33 provided in the upper surface 32 of the cylinder member 30 is provided.
A plurality of protrusions 42D that are engaged with the cylinder are formed so that the cylinder member 30 can be reliably rotated together with the flow forming die 41.
In addition, FIG. 4A is an explanatory view showing an enlarged part C of FIG.
FIG. 4B is a diagram showing FIG. 4A in the arrow direction.

The flow forming roller 43 has a first outer peripheral surface portion 43A facing the back surface 22 of the movable sheave 20,
Second outer peripheral surface portion 43 facing the flow forming mold 42
It has a short-axis cylindrical shape having B. The rotation center L2 is the base material holding die 41 and the flow forming die 42.
It is rotatably supported by a support arm (not shown) in a posture intersecting the rotation center L1. Also,
While being pressed from the upper surface 32 side of the cylinder member 30 to the second outer peripheral surface 43B, the second outer peripheral surface 43B is connected to a roller moving means (not shown) that moves along the rotation center L1 and in a direction toward or away from the rotation center L1. There is.

Next, a method of molding the cylinder member 30 and connecting it to the movable sheave 20 by using the flow forming machine 40 having the above-mentioned structure will be described.

First, the movable sheave 20 is held in the base material holding die 41, and the cylinder member before molding is fitted in the movable sheave 20, and the flow forming die 42 is lowered to form the base material holding die 41. The cylinder member 30 and the movable sheave 20 are sandwiched between them, and the base material holding die 41 and the flow forming die 42 are rotatably set together.

Positioning of the cylinder member 30 with respect to the movable sheave 20 at the time of setting is performed by a fitting operation in which the boss portion 24 of the movable sheave 20 is inserted into the center hole 31 of the cylinder member 30 and fitted therein. As another embodiment, as shown in an enlarged sectional view of a main part in FIG. 5, the flange portion 3 formed by bending the outer peripheral edge of the cylinder member 30.
4 may be positioned by engaging the outer peripheral end portion 28 of the pulley portion 21. Further, as still another embodiment, as shown in an enlarged sectional view of a main part in FIG. 6, an outer peripheral surface 35 of the cylinder member 30 and a facing surface 41A of a base material holding die 41 formed so as to face the outer peripheral surface 35. Alternatively, the positioning may be performed by the engagement of.

When the cylinder member 30 and the movable sheave 20 are set, rotation of the base material holding die 41 and the flow forming die 42 is started by driving means (not shown). Then, the first outer peripheral surface 43A of the flow forming roller 43 is pressed against the upper surface 32 of the cylinder member 30 with a predetermined pressing force, and in this pressed state, the second outer peripheral surface 43B approaches the outer peripheral surface 42B of the flow forming mold 42. The flow forming roller 43 is moved in the direction.

As a result, the cylinder member 30 is squeezed by the flow forming roller 43 and plastically deformed,
The thick portion of the cylinder member 30 is formed so as to approach the radial center (the direction of the thick arrow in FIGS. 1 and 2).
The thick portion of the cylinder member 30 that is moved closer to the radial center is pressed against the outer peripheral surface 42B of the flow forming mold 42 by the second outer peripheral surface 43B, and finally,
As shown in FIG. 2, the back surface 22 of the movable sheave 20 is formed into a cylindrical shape having a predetermined tube thickness and standing upright. Since the cylinder member 30 can be molded without causing springback in the elastic deformation region as in the conventional press molding, the accuracy can be as high as that of machining. In addition, work hardening is large due to cold plastic working,
Since the metal structure is not cut as in the cutting process, mechanical properties such as tensile strength, toughness, and fatigue strength can be enhanced more than the cylinder member 30 before forming.

Further, due to such plastic deformation, at the same time when the cylinder member 30 is formed, a part of the cylinder member 30 is pushed into the annular groove 25 and the detent hole 26 by plastic deformation. A part of the cylinder member 30 is engaged with the annular groove 25 so that the cylinder member 30 is firmly connected to the movable sheave 20,
Further, by being engaged with the rotation stop hole 26, the relative rotational movement with respect to the movable sheave 20 is restricted.

Therefore, the cylinder member 30 can be molded and connected to the movable sheave 20. Thereby, the forming process of the cylinder member 30 and the connecting process to the movable sheave, which are conventionally separate processes and independent from each other, can be integrated into one process. Therefore, the number of man-hours for assembling the pulley of the belt type continuously variable transmission can be reduced by that amount, and the product cost can be reduced.

(Second Embodiment) FIG. 7 is a schematic view for explaining the second embodiment. The same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The fixing means 45 is a base material holding type 41.
The central hole 45A into which the boss portion 24 of the movable sheave 20 supported by the above is inserted and the downward movement in synchronism with the flow forming die 47, thereby abutting on the radial center portion of the cylinder member 50 and the base material. It has a lower end surface 45B that holds the cylinder member 50 and the movable sheave 20 between the holding die 41 and the holding die 41.

The flow forming die 47 is vertically movable above the base material holding die 41, and the base material holding die 4 is provided.
1 and a lower end surface 47A that is rotatably provided integrally with the first sheave 1 and contacts the rear surface 22 of the movable sheave 20 when descending, and the rear surface 2
2 and an inner diameter hole 48 having an inner peripheral wall surface 48A rising from 2.

The flow forming roller 49 includes a first outer peripheral surface portion 49A facing the back surface 22 of the movable sheave 20, and
The flow forming die 47 has a second outer peripheral surface portion 49B facing the inner peripheral wall surface 48A. And the center of rotation L
3 is rotatably supported by a support arm (not shown) in a posture in which it intersects with the center of rotation L1 of the base material holding die 41 and the flow forming die 42. Also, the second
While being pressed from the upper surface 52 side of the cylinder member 50 to the outer peripheral surface 49B, the outer peripheral surface 49B is connected to a roller moving unit (not shown) that moves along the rotation center L1 and the direction toward or away from the rotation center L1.

Next, a method of forming the cylinder member 50 and connecting it to the movable sheave 20 by using the flow forming machine 40 having the above structure will be described. First, the movable sheave 20 is held by the base material holding die 41, and the cylinder member 50 before molding is fitted to the movable sheave 20.
Then, the fixing means 45 and the flow forming die 47 are lowered, the cylinder member 50 and the movable sheave 20 are sandwiched between the fixing means 45 and the base material holding die 41, and the base material holding die 41 and the flow forming die 47 are formed. Set so that they can rotate together.

Then, by lowering the flow forming die 47, the lower end surface 47A of the flow forming die 47 is brought into contact with the back surface 22 of the movable sheave 20, and the inner peripheral wall surface 48A of the inner diameter hole 48 is positioned at the outer side in the radial direction of the back surface 22. Deploy.
Further, the cylinder member 50 and the movable sheave 20 are held between the base material holding die 41 and the fixing means 45, and the base material holding die 41 and the flow forming die 47 are rotatably set together. Positioning of the cylinder member 50 on the movable sheave 20 at the time of setting is performed by inserting the boss portion 24 of the movable sheave 20 into the central hole 51 of the cylinder member 50, as in the first embodiment.

When the cylinder member 50 and the movable sheave 20 are set, the rotation of the base material holding die 41 is started, and the cylinder member 50 and the movable sheave 20 are integrally rotated.

Then, the flow forming roller 49
Is inserted into the inner diameter hole 48 from above the flow forming die 47 by a roller moving means (not shown), and the second outer peripheral surface 49B of the flow forming roller 49 is pressed against the upper surface 52 of the cylinder member 50 with a predetermined pressing force. . Then, while maintaining such a pressed state, it is moved outward in the radial direction and further moved upward along the inner peripheral wall surface 48A of the inner diameter hole 48. As a result, the cylinder member 50 is squeezed by the flow forming roller 49,
It causes plastic deformation.

Due to such plastic deformation, the thick portion of the cylinder member 50 is formed so as to be closer to the outside in the radial direction (the direction of the arrow in FIG. 7), and is further erected on the rear surface 22 along the inner peripheral wall surface 48A. To be molded. And
Finally, the rear surface 22 of the movable sheave 20 is formed into a cylindrical shape having a predetermined tube thickness and standing upright.

Further, due to such plastic deformation, a part of the cylinder member 50 has an annular groove 25 on the back surface 22 of the movable sheave 20.
And the detent hole 26 is engaged. The cylinder member 50 is
By engaging a part of it with the annular groove 25, it is integrally coupled to the movable sheave 20, and by engaging with the rotation stop hole 26, relative rotational movement with the movable sheave 20 is restricted.

By the above method, the cylinder member 50 can be molded and coupled to the movable sheave 20.
As a result, it is possible to integrate the forming process of the cylinder member 50 and the connecting process to the movable sheave 20, which are separate processes that are conventionally independent of each other. Therefore, the man-hours can be reduced by that amount, and the product cost can be reduced.

The above-mentioned invention is not limited to the above-mentioned embodiment, but various modifications can be made without departing from the gist of the invention. For example, in the above-described embodiment, the case of the pulley of the belt type continuously variable transmission has been described as an example, but the invention can be applied to other cases. Further, the shape of the annular groove 25 and the shape of the rotation stop hole 26 are also the cylinder member 3.
A part of 0 and 50 is engaged by plastic deformation and the movable sheave 2
It is sufficient that the cylinder members 30 and 50 can be integrally connected to 0.

Further, in the above-described embodiment, the flow forming dies 42, 47 are used to form the cylinder members 30, 50.
However, the flow forming molds 42 and 47 may not be provided.

[0054]

As described above, according to the member joining method and member joining structure of the present invention, the members to be molded can be molded and joined to the base material, so that they are independent of each other in the past. It is possible to integrate the molding process and the joining process that have been performed, and the number of assembling steps can be reduced accordingly. Further, before the forming and joining of the members to be molded, the base material can be subjected to another treatment such as heat treatment in advance, and a product in which the specific treatment is applied to a specific portion of the component can be easily manufactured.

[Brief description of drawings]

FIG. 1 is an explanatory view conceptually showing a method of molding a cylinder member and coupling it to a movable sheave.

FIG. 2 is an explanatory view schematically showing a method of molding a cylinder member and coupling the cylinder member to a movable sheave.

FIG. 3 is a diagram illustrating an engaging portion of a movable sheave.

FIG. 4 is a diagram illustrating a fixed state of a cylinder member.

FIG. 5 is a diagram illustrating a method of positioning a cylinder member on a movable sheave.

FIG. 6 is a diagram illustrating a method of positioning a cylinder member on a movable sheave.

FIG. 7 is a schematic diagram illustrating a second embodiment.

FIG. 8 is a diagram illustrating a conventional technique.

[Explanation of symbols]

Reference Signs List 20 movable sheave (base material) 22 back surface 25 annular groove (engagement portion) 26 rotation stop hole (engagement portion) 30 cylinder member (molded member in the first embodiment) 40 flow forming machine 41 base material holding Mold 42 Flow Forming Type (First Embodiment) 43 Flow Forming Roller (First Embodiment) 45 Fixing Means 47 Flow Forming Type (Second Embodiment) 49 Flow Forming Roller (Second Embodiment) Form) 50 Cylinder member (member to be molded in the second embodiment)

Claims (9)

[Claims] 1. A base material having an engaging portion is held by a base material holding die, a member to be molded is fitted to the base material, the base material holding die is rotationally driven, and a flow forming roller is attached to the base material holding die. Pressing the molding member to plastically mold the member to be molded, and engaging a part of the member to be molded with the engaging portion of the base material by plastic deformation to bond the member to be molded and the base material. And a member connecting method. 2. The member joining method according to claim 1, wherein the plastic forming of the member to be molded is performed by moving the flow forming roller while pressing the flow forming roller against the member to be molded. 3. The plastic forming of the member to be formed is performed by the cooperation of a flow forming roller and a flow forming roller that are rotationally driven integrally with the base material holding die. The method for joining members according to item 4. 4. The member joining method according to claim 3, wherein the flow forming mold is integrally formed with the base material holding mold. 5. The base material is the movable sheave of a belt type continuously variable transmission pulley having a fixed sheave provided on a shaft and a movable sheave, the pulley width of which is variably controlled. The member is a hydraulic actuator member that is provided on the back surface of the movable sheave and variably controls the movable sheave, and the engaging portion is formed on the back surface of the movable sheave. The member joining method according to any one of claims. 6. The member coupling method according to claim 1, wherein the engagement portion includes an annular groove that is continuously provided in a circumferentially recessed manner. 7. The member joining method according to claim 6, wherein the annular groove has a dovetail groove cross-sectional shape in which a pair of groove vertical wall surfaces are separated from each other as the annular groove moves to the groove bottom surface. . 8. The engagement portion has a detent hole, which has a predetermined diameter and a predetermined depth and is recessed at predetermined intervals in the circumferential direction. The member coupling method as described in 1. 9. A base material having an engaging portion held by a base material holding die is fitted with a base material, and a flow forming roller is pressed against the base material while rotating the base material holding die. The member coupling structure characterized in that the member to be molded and the base material are bonded to each other by plastically molding the member to be molded and at the same time engaging a part of the member to be molded by plastic deformation with the engaging portion.