JP2003322168A - Joining structure of rotary element with drive shaft to rotary structure and joining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joining structure of a rotary element of a rotary structure with its drive shaft and a joining method associated therewith capable of establishing large coupling strength by using both screw coupling and pressure fit coupling, eliminating the risk of the loosening of coupling between the rotary element and the drive shaft even when torque in the opposite direction relative to the normal rotating direction is applied to the drive shaft, for example, when rotation is stopped, eliminating the risk of the dislocation or inclination of the axis, and establishing coupling of high reliability. <P>SOLUTION: A rotor 1 of a vane pump is composed of the rotary element 2 made of aluminum or an aluminum alloy and the drive shaft 3 made of steel. The rotary element 2 has a preparatory hole 6 and a fitting hole 7 while the drive shaft 3 has a shaft 8, a tapping screw 9 and a pressure fitting part 10 at its joining side end, and when the tapping screw 8 is driven into the hole 6, a screw coupling part A is formed, and when the pressure fitting part 10 is fitted by pressure in the fitting hole 7, a pressure fit coupling part B is formed. The shaft 8 and a pressure fit coupling part A support two ends of the rotary element 2. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining structure for a rotating body and a drive shaft in a rotating structure and a joining method thereof.

[0002]

2. Description of the Related Art A rotary structure of a drive system, for example, a rotor of a vane pump, has a shaft, a rotor body provided on the shaft, and a plurality of sheets inserted into and retracted from a sliding groove provided on the outer periphery of the rotor body. It is composed of vanes and is designed so that it normally rotates only in one direction. Also, due to the demand for weight reduction, aluminum is being used. However, if the rotor shaft part (drive shaft) is made of aluminum, the strength will be insufficient. Therefore, the shaft part is usually made of steel to maintain torsional rigidity, and only the rotor body (rotating body) will be made of aluminum or aluminum alloy material. The rotor is manufactured by integrally manufacturing these parts.

Since it is difficult to weld dissimilar metals to each other as a joining structure of a drive shaft and a rotating body in an ordinary rotating structure, they are joined by using mechanical joining means such as bolts or friction welding (FW). : Friction Welding), Friction Stir Welding (FSW), press fitting (shrink fit), casting, forging, etc.

Of these, the FW is constructed by applying a friction pressure to a pair of metal members to be joined and rotating them relatively to each other.
With the method of joining the joints in a semi-molten state by frictional heat, there is an advantage that the joints between similar metals can be joined in a short time by an established technique, but between the dissimilar metals, the method disclosed in Japanese Patent Application Laid-Open No. Hei 5 (1999) -5 is used. As described in Japanese Patent Publication No. 293676, it is a special technique which has not yet been used for general purpose at the present time.

The FSW restrains the metal members to be joined in contact with each other, and pushes a tool into the joining end to rotate it and move it along the joining surface to cause plastic flow of the metal due to friction at the joining end. This is a method of causing the metal to join (Example: Japanese Patent Laid-Open No. 7-47480), in which each joining end of the metal member does not melt, and M
Compared to IG welding, TIG welding, etc., there is less influence of heat, and it is advantageous in terms of strength and at the same time is advantageous in terms of cost.

Another joining structure is, for example, Japanese Patent Publication No. 6-
The joint structure disclosed in Japanese Patent No. 72616 is known. This joint structure uses spline fitting,
On the outer peripheral surface of the portion of the shaft to which the rotor is joined, a concavo-convex portion that is formed alternately in the circumferential direction and has a long axial concave portion and a convex portion is provided. And the rotor are integrally joined.

[0007]

However, all of the above-described conventional joining structures employ only one type of joining method, so that there is a problem that the joining reliability is low. For example, the screw joint type joint structure prevents loosening by screwing a male screw threaded in the direction opposite to the direction of rotation during normal use. When a shock or the like in the direction is applied, the joint is loosened to lower the joint strength, the rotating body is shaken, and in the worst case, the drive shaft is disengaged from the rotating body. Friction welding cannot be said to be a well-established technique for joining dissimilar metals, and friction stir welding is difficult to replace the shaft with the prior art.

The present invention has been made to solve the above-mentioned conventional problems. The object of the present invention is to obtain a large joint strength by using a screw connection and a press-fit connection together, and to obtain a normal rotation. Even if a rotation in the opposite direction occurs, it does not loosen, nor does the axis shift or tilt, and it is possible to obtain a highly reliable joint structure. To provide a joining structure of a rotating body and a drive shaft in the above and a joining method thereof.

[0009]

In order to achieve the above object, the joint structure of the rotary body and the drive shaft in the rotary structure according to the first aspect of the present invention is a metal rotary body and has a melting point higher than that of the rotary body. In a rotating structure including a drive shaft made of high metal, the rotating body and the drive shaft are integrally joined by a screw coupling portion and a press-fitting coupling portion.

According to the first aspect of the present invention, the screw coupling portion reliably transmits the driving force when the rotating body is driven by the drive shaft, and the coupling force of the press-fitting coupling portion prevents loosening of the screw coupling portion even during stop braking. To do. In addition, the rotating body and the drive shaft are positioned to make the insertion dimension constant, and the misalignment and inclination of the axis line are corrected.

A second invention is the same as the first invention,
The rotating body is made of aluminum or an aluminum alloy material, and the drive shaft is made of steel material.

In the second aspect of the invention, the rotating body is made of aluminum or an aluminum alloy material, so that the weight of the rotating structure can be reduced. Since the drive shaft is made of steel, it has high torsional rigidity and high bending rigidity and strength.

According to a third aspect of the present invention, in the first or second aspect of the invention, the screw coupling portion includes a prepared hole formed in the rotating body and a tapping screw formed in the drive shaft and screwed into the prepared hole. The inner diameter of the prepared hole and the effective diameter of the tapping screw are substantially the same, and the prepared screw is screwed into the prepared hole to be plastically deformed to form a female screw in close contact with the tapping screw. .

In the third invention, the tapping screw is screwed while plastically deforming the pilot hole to form a female screw in the pilot hole. In this case, since the inner diameter of the prepared hole and the effective diameter of the tapping screw are almost the same, the cross-sectional area of the part that bites into the hole wall of the prepared hole of the screw of the tapping screw and the inner wall of the prepared hole The cross-sectional area of the plastically deformed portion that bulges in the direction becomes substantially equal. Therefore, the female screw formed in the prepared hole is a thread groove having substantially the same shape as the thread of the tapping screw, and the plastically deformed portion fills the gap between the prepared hole and the tapping screw. Therefore, the tapping screw and the female screw are in close contact with each other over substantially the entire surface, increasing the coupling strength of the screw coupling portion.

A fourth invention is the above-mentioned first, second or third invention.
In the invention, the tapping screw of the drive shaft is threaded in the same direction as the rotating direction of the rotating structure during normal use.

In the fourth aspect of the invention, the tapping screw is threaded in the same direction as the normal rotation direction of the rotary structure, so that the threaded connection portion is loosened even when a rotational force is applied to the drive shaft during normal rotation. There is no.

According to a fifth aspect of the present invention, in the first or second aspect of the invention, the screw coupling portion is formed by friction stir welding of a prepared hole formed in the rotating body and a male screw portion formed in the drive shaft. The inner diameter of the prepared hole and the effective diameter of the male screw portion are substantially equal to each other, and the male screw portion is rotated in a direction of advancing the metal softened to a plastically deformable state by friction heat during friction stir welding. It is pushed into the pilot hole.

In the fifth invention, the drive shaft is used as a friction stir tool at the time of friction stir welding, and is pushed into the prepared hole of the rotating body. In friction stir welding, the drive shaft is rotated at a high speed in the direction in which the male screw part moves backward and the softened metal is advanced, and is pushed into the prepared hole of the rotating body. When the male screw portion is pushed in, a plastic flow of metal is generated in the rotating body by frictional heat, and the rotating body and the screw coupling portion of the drive shaft are joined. Therefore, the threaded joint does not melt, and is less affected by heat as compared with MIG welding, TIG welding, etc. as in friction welding, and is also advantageous in strength. Since the rotation direction of the male screw at the time of friction stir welding is the direction of advancing the softened metal, the screw portion formed on the shaft and the rotating body are surely brought into close contact with each other. Further, as a result of the joining, the drive shaft can be disassembled and replaced by rotating the screw in the reverse direction with a strong force as in the case of the screw-coupled one.

A sixth aspect of the invention is the same as the fifth aspect of the invention.
The male screw portion formed on the drive shaft is threaded in the same direction as the rotating direction of the rotary structure during normal use.

In the sixth invention, since the direction of the screw of the male screw portion formed on the drive shaft is threaded in the same direction as the rotation direction of the rotary structure during normal use, the fourth invention is the same as the fourth invention. Similarly, even if a rotational force is applied to the drive shaft at the time of normal rotation, the screw connection portion does not loosen.

In a seventh aspect of the invention, in any one of the first to sixth aspects of the invention, the pilot hole of the rotary body is a non-through hole having a length substantially equal to the length from the joint side end of the drive shaft to the press-fitting portion. It is what

The seventh aspect of the invention is effective when a cantilever type drive shaft is required because the drive shaft does not penetrate the rotating body.

An eighth aspect of the present invention is any one of the first to seventh aspects, wherein the joint side end of the drive shaft has a shaft portion having the same or slightly smaller outer diameter as the prepared hole of the rotor. Is formed, and the shaft portion and the press-fitting portion support the rotating body at both ends.

In the eighth aspect of the invention, the shaft portion and the press-fitting portion are suitable for application to the drive shaft and the rotary body which support the rotary body at both ends.

According to a ninth aspect of the present invention, there is provided a method for joining a rotary body and a drive shaft in a rotary structure, wherein the drive shaft is made of a metal material having a melting point higher than that of the rotary body, and an end portion of the rotary body joined to the rotary body. To provide a tapping screw and a press-fitting part, which are threaded in the same direction as the rotating direction of the rotary structure during normal use, screw the tapping screw into the prepared hole, and press-fit the press-fitting part into the fitting hole. With this, the rotating body and the drive shaft are integrally joined.

In the ninth invention, when the tapping screw is screwed into the pilot hole and the press-fitting portion is press-fitted into the fitting hole,
The rotating body and the drive shaft are integrally joined.

In a tenth aspect based on the ninth aspect, the effective diameter of the tapping screw of the drive shaft is substantially equal to the inner diameter of the pilot hole of the rotating body, and the tapping screw is screwed into the pilot hole so that the plasticity is improved. By being deformed, a female screw that is in close contact with the tapping screw is formed.

In the tenth aspect of the invention, the prepared hole is plastically deformed by the tapping screw to form an internal thread, and the plastically deformed portion bulging toward the center of the prepared hole is in close contact with the tapping screw to bond strength. Increase.

According to an eleventh aspect of the present invention, in a method for joining a rotating body and a drive shaft in a rotating structure, a pilot hole and a fitting hole are formed in the rotating body, and the drive shaft is made of a metal material having a melting point higher than that of the rotating body. By providing a male screw portion and a press-fitting portion at the end portion on the joint side with the rotating body, and rotating the drive shaft in the direction of advancing the softened metal to a state where the male screw portion is plastically deformable by frictional heat. While pressing the male screw portion into the pilot hole of the rotating body to friction stir weld the male screw portion and the pilot hole, and press fit the press fitting portion into the fitting hole to connect the rotating body and the drive shaft. They are joined together.

In the eleventh aspect, the male screw portion and the prepared hole are friction stir welded. Friction stir welding pushes the softened metal into the prepared hole while rotating the drive shaft at a high speed in the direction of advancing the softened metal. When the male screw portion is pushed in, a plastic flow of metal is generated in the rotating body by frictional heat, and the rotating body and the screw coupling portion of the drive shaft are joined. The male screw portion is not limited to a normal screw and may be a tapping screw.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the drawings. 1 is a front view of a rotary structure adopting a joining structure according to the present invention, FIG. 2 is a right side view of the same rotary structure, FIG. 3 is an enlarged sectional view of the same rotary structure, and FIG. 4 is a view before joining. Sectional view showing the rotating body, FIG.
FIG. 6 is a front view showing a drive shaft before being similarly joined. In the present embodiment, an example applied to a rotor of a vane pump as a rotating structure is shown.

The vane pump rotor, generally designated by reference numeral 1, is composed of a rotor 2 which constitutes the rotor body, and a drive shaft 3 which is attached to the rotor 2. Rotating body 2
Is formed of aluminum or an aluminum alloy in a cylindrical shape, and two vane sliding grooves 5 into which the vanes 4 are retractably inserted are formed on the outer peripheral surface so that the vane sliding grooves 5 are 180 degrees out of phase with each other in the circumferential direction. 2 are integrally joined to each other by a screw joint portion A and a press-fit joint portion B. Therefore, the rotary body 2 is formed with a through hole at the center thereof and the drive shaft 3
A pilot hole 6 into which is screwed is formed, and a fitting hole 7 is further formed at an opening of one end of the pilot hole 6. The hole diameter of the fitting hole 7 is set sufficiently larger than the inner diameter of the pilot hole 6.

The drive shaft 3 is made of steel, which is a material for ensuring a sufficient torsional rigidity and strength as compared with the rotary body 2, and the shaft portion 8 is provided at the end portion on the joint side with the rotary body 2. The tapping screw 9 and the press-fitting portion 10 are formed in series. The shaft portion 8 supports both ends of the rotating body 2 together with the press-fitting portion 10, and the shaft hole 6
Has an outer diameter slightly smaller than the inner diameter of. The fitting between the prepared hole 6 and the shaft portion 8 is loose fitting or sliding fitting. The tapping screw 9 is threaded in the same direction as the normal rotation direction of the rotor 1 (the direction of the arrow in FIG. 2) in order to prevent the screw from loosening when a rotational force acts on the shaft portion 8 of the rotating body. There is. In other words, the tapping screw 9 is threaded in the direction in which the drive shaft advances when a rotational force for rotating the rotor 1 in the normal use direction is applied to the drive shaft. For example, a left-hand tapping screw 9 is formed when the rotor 1 rotates counterclockwise, and a right-hand tapping screw 9 is formed when the rotor 1 rotates right. The tapping screw 9 is formed so that its effective diameter is substantially equal to the inner diameter of the pilot hole 6.

The press-fitting portion 10 has a disk shape whose thickness is substantially equal to the depth of the fitting hole 7, the outer diameter thereof is set to be slightly larger than the hole diameter of the fitting hole 7, and the tapping screw 9 is lowered. When it is screwed into the hole 6, it is press-fitted into the fitting hole 7 to form the press-fitting joint portion B together with the fitting hole 7. The fit between the fitting hole 7 and the press-fitting portion 10 is preferably M or more, which has a large interference so as to increase the coupling strength and prevent the rotor 2 from loosening due to vibration, impact, reverse rotation, or the like.

To assemble the rotor 1 having such a structure, the axis of the rotary body 2 and the axis of the drive shaft 3 are aligned with each other, and the shaft portion 8 of the drive shaft 3 is fitted into the prepared hole 6 of the rotary body 2. The tapping screw 9 may be inserted into the hole 7 side and the tapping screw 9 may be cold screwed into the pilot hole 6, and the press-fitting portion 10 may be press-fitted into the fitting hole 7. When the tapping screw 9 is screwed into the pilot hole 6, since the rotating body 2 is made of aluminum or an aluminum alloy that is softer than the drive shaft 3, the top of the thread of the tapping screw 9
Strictly speaking, a portion outside the effective diameter is screwed while plastically deforming the pilot hole 6 to form the female screw 11. In this case, if the inner diameter of the prepared hole 6 and the effective diameter of the tapping screw 9 are substantially matched, the cross-sectional area of the portion of the screw of the tapping screw 9 that bites into the hole wall, and the bited portion 6 The cross-sectional area of the plastically deformed portion in which the inner wall of swells in the center direction can be made substantially equal. That is, the tapping screw 9 is transferred to the prepared hole 6. Therefore, the internal thread 11 formed in the prepared hole 6 is a thread groove having the same shape as the thread of the tapping screw 9,
The plastically deformed portion bulging in the central direction fills the gap between the pilot hole 6 and the tapping screw 9. Therefore, the tapping screw 9 and the female screw 11 are in close contact with each other over substantially the entire surface thereof, and the screw coupling portion A is formed by them.

When the tapping screw 9 is forcibly screwed into the pilot hole 6 in the cold state, the tip of the shaft portion 8 projects from the pilot hole 6 to the outside, and the press-fitting portion 10 is press-fitted into the fitting hole 7. The fitting hole 7 and the press-fitting portion 10 form a press-fitting coupling portion B, and thus the rotor 1 is assembled. That is, the rotating body 2 and the drive shaft 3 include a female screw 11 formed in the pilot hole 6 and a screw coupling portion A formed by a tapping screw 9 screwed into the pilot hole 6,
The fitting hole 7 and the press-fitting joint portion B of the press-fitting portion 10 are integrally joined.

In the rotor 1 having such a structure, the rotor 2 and the drive shaft 3 are connected to each other by the screw coupling portion A and the press-fitting coupling portion B.
Since they are joined by and, they can be joined with high joining strength. In this case, if only the screw coupling portion A is used, a rotational force in a direction in which the rotor 1 rotates in the opposite direction may act on the drive shaft due to the inertia force when the rotor 1 is stopped, and the screw coupling portion A may loosen. Since the connecting portion B is provided, the possibility thereof is small, and it is possible to reliably prevent the rotating body 2 from rattling and coming off from the drive shaft 3.

Since both ends of the rotating body 2 are supported by the shaft portion 8 and the press-fitting portion 10, the swinging motion of the rotating body 2 can be prevented. Further, the press-fitting coupling portion B defines the insertion amount of the drive shaft 3 with respect to the rotating body 2 by the press-fitting portion 10 being press-fitted into the fitting hole 7 and abutting the bottom surface thereof, and the rotating body 2 and the drive shaft 3 are aligned with each other. Position in the direction. Further, the press-fitting portion 10 is press-fitted into the fitting hole 7, so that the axis of the rotating body 2 and the axis of the drive shaft 3 are aligned with each other. Therefore, even though the structure is simple, the axes do not shift or tilt, and dissimilar metals can be accurately bonded with high bonding strength, and the rotating body of the rotating structure and the drive shaft can be bonded. The structure is optimal.

Here, in the above-mentioned embodiment,
Although the tapping screw 9 is slowly screwed into the prepared hole 6 to form the screw joint A, the screw joint A may be formed by a friction stir welding method as another method.

In the case of friction stir welding, the rotating body 2 and the drive shaft 3 are rotated at a relatively high speed (500 to 50000 rpm), and the tapping screw 9 is pushed into the prepared hole 6 to generate friction heat. Softens the metal near the inner wall of the pilot hole 6 to a state where it can be plastically worked,
After stirring and flowing by the stirring action by high-speed rotation, the rotation may be stopped and the press-fitting portion 10 may be press-fitted into the fitting hole 7 to cool and solidify the heat-softened metal. Also in this case, if the inner diameter of the prepared hole 6 and the effective diameter of the tapping screw 9 are substantially matched, the metal that has been agitated and fluidized fills the gap between the inner wall of the prepared hole 6 and the tapping screw 9 and becomes the tapping screw 9. Internal thread 11 of the same shape
Is formed, and the screw joint A can be formed by friction stir welding. Since the screw connection portion A by such friction stir welding does not utilize plastic deformation but plasticizes by utilizing frictional heat, it is possible to perform welding with a relatively small force.

When the rotary body 2 and the drive shaft 3 are joined only by the screw joint portion A by friction stir welding,
Since the metal near the inner wall of the prepared hole 6 is softened to a state where it can be plastically machined, the rotating body 2 may be eccentric with respect to the drive shaft 3 or the axis line may be inclined, but the shaft portion 8 and the press-fitting fit. Since both ends of the rotating body 2 are supported by the joint portion B, there is no risk of the rotating body 2 being eccentric with respect to the drive shaft 3 or the axis line being inclined, and stable and reliable joining can be achieved. When the threaded joint A is formed by friction stir welding, unlike the normal threaded joint A, the drive shaft 3 is softened by frictional heat and pushed into the drive shaft 3, so that the drive shaft 3 is formed. The external thread part to be used is not limited to the tapping screw 9 but a normal external thread (for example: metric thread)
You may comprise.

Further, the screw joint portion A is formed by friction stir welding.
In the case of forming a hole, a form in which the prepared hole does not penetrate (Figs. 9 to 1)
1: The friction stir welding will be described later in detail), and the threading direction of the male screw portion formed on the drive shaft 3 is preferably the same as the rotation direction of the rotating structure. In the case of friction stir welding, when the drive shaft 3 is pushed in while rotating in the direction in which the male screw portion advances, the metal softened by frictional heat is discharged from the prepared hole 6, so the male screw portion moves backward and the softened metal is advanced. It is necessary to push in while rotating in the direction. For example, when the normal rotation direction of the rotor 1 is the right direction,
If the male screw part is a right-hand screw and the drive shaft 3 is rotated to the left and pushed into the prepared hole 6 at the time of friction stir welding,
The softened metal is not discharged from the pilot hole 6, the gap between the pilot hole 6 and the male screw portion can be filled, and a favorable screw coupling portion A can be obtained.

FIG. 6 is a sectional view of a rotating structure showing another embodiment of the joining structure according to the present invention, FIG. 7 is a sectional view showing a rotating body before joining, and FIG. 8 is a driving before joining. It is a front view which shows a shaft. The same components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

In this embodiment, a boss portion 2A is integrally provided at the center of one side surface 13 of the rotating body 2 made of an aluminum alloy material, and the other side surface 14 is provided at the center of the tip end surface of the boss portion 2A. A pilot hole 6 formed of a through hole that opens is formed, and a fitting hole 7 is formed on the open end surface of the pilot hole 6 on the boss portion 2A side. On the other hand, in the drive shaft 3 made of steel, the shaft portion 8, the tapping screw 9 and the press-fitting portion 10 are formed in series at the end portion on the joint side with the rotating body 2 as in the above-described embodiment. Is inserted into the pilot hole 6 and the boss 2
The opening on the side opposite to the A side is closed, the tapping screw 9 is screwed into the pilot hole 6, and the press-fitting portion 10 is press-fitted into the fitting hole 7, so that the rotating body 2 and the drive shaft 3 are screwed together.
And the press-fitting joint B are integrally joined. The inner diameter of the prepared hole 6 and the effective diameter of the tapping screw 9 are substantially the same. The tapping screw 9 is threaded so as to be a right-hand screw when the rotor normally rotates to the right. Therefore, the structure is the same as that of the above-described embodiment except that the boss portion 2A is integrally provided on the rotating body 2, and the other structure is exactly the same.

It will be apparent that the rotating body 2 and the drive shaft 3 can be firmly joined to each other even in such a joining structure as in the above-described embodiment.

FIG. 9 is a cross-sectional view of a rotary structure showing still another embodiment of the joining structure according to the present invention, FIG. 10 is a cross-sectional view showing a rotating body before joining, and FIG. 11 is the same as before joining. It is a front view which shows a drive shaft. In this embodiment,
One side surface 13 of the rotating body 2 made of an aluminum alloy material
A boss portion 2A is integrally provided in the center of the boss 2A, a pilot hole 20 formed of a non-through hole is formed in the center of the tip surface of the boss portion 2A, and a fitting hole 21 is formed at the open end of the pilot hole 20. ing. On the other hand, in the drive shaft 3 made of steel, the shaft portion 8, the tapping screw 9 and the press-fitting portion 10 are formed in series at the end portion on the joint side with the rotating body 2 as in the above-described embodiment. Is inserted into the prepared hole 6, the tapping screw 9 is screwed into the prepared hole 20, and the press-fitting portion 10 is press-fitted into the fitting hole 21, whereby the rotary body 2 and the drive shaft 3 are press-fitted and coupled to the screw coupling portion A. The part B is integrally joined.
The shaft portion 8 has a diameter slightly smaller than the inner diameter of the prepared hole 20. The inner diameter of the prepared hole 20 and the effective diameter of the tapping screw 9 are substantially equal. That is, the present embodiment is different from the above-described embodiments in that the prepared hole 20 formed in the rotating body 2 is a non-through hole.

Thus, instead of screwing the tapping screw 9 into the pilot hole 20 to plastically deform the pilot hole 20, as another method, the threaded joint A is formed by the friction stir welding method described above. You may.

Even in such a structure, it will be apparent that the rotary body 2 and the drive shaft 3 can be firmly joined to each other as in the above-described embodiment.

In each of the above embodiments, the rotary body 2 is made of aluminum or aluminum alloy material, and the drive shaft 3 is made of steel material, but the present invention is not limited to this. It is also possible to use other dissimilar metals, and the point is that the drive shaft 3 has higher torsional rigidity / bending rigidity and strength than the rotating body 2 and has a high melting point. Good.

[0050]

As described above, in the joining structure of the rotating body and the drive shaft in the rotating structure according to the present invention and the joining method thereof, the rotating body and the drive shaft are integrally formed by the screw connecting portion and the press-fitting connecting portion. Since they are joined, a greater joining strength can be obtained compared to the case where they are joined only by screw joints or only press-fit joints, and even when a rotational force in the reverse rotation direction acts on the drive shaft due to the inertia of the rotor during stoppage, etc. The joint between the rotary body and the drive shaft does not loosen, and a highly reliable joint structure can be obtained. Further, the formation of the screw connection and the press-fit connection is advantageous in terms of cost because no special device is required. Further, the press-fitting portion defines the insertion amount of the drive shaft, and prevents the tilt by aligning the axis of the rotating body with the drive shaft.

In the invention in which the threaded joint is formed by friction stir welding, since the threaded joint does not form the joint by plastic deformation, sufficient joining strength can be obtained with a relatively small processing force. The reliability of can be increased.

In the invention in which the shaft portion protruding from the rotating body at the tip of the drive shaft is provided, both ends of the rotating body are supported by the shaft portion and the press-fitting coupling portion, so that the rotating body is inclined with respect to the drive shaft. And can be supported in a stable state.

[Brief description of drawings]

FIG. 1 is a front view of a rotary structure that employs a joining structure according to the present invention.

FIG. 2 is a right side view of the rotary structure of the same.

FIG. 3 is an enlarged cross-sectional view of the rotary structure of the same.

FIG. 4 is a cross-sectional view showing a rotating body before being joined.

FIG. 5 is a front view showing a drive shaft before being similarly joined.

FIG. 6 is a sectional view of a rotary structure showing another embodiment of the present invention.

FIG. 7 is a cross-sectional view of a rotating body before being joined.

FIG. 8 is a front view showing the drive shaft before being similarly joined.

FIG. 9 is a cross-sectional view of a rotary structure showing still another embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a rotating body before being joined.

FIG. 11 is a front view showing the drive shaft before being similarly joined.

[Explanation of symbols]

1 ... Rotor (rotating structure), 2 ... Rotating body, 3 ... Drive shaft,
6 ... Prepared hole, 7 ... Fitting hole, 8 ... Shaft part, 9 ... Tapping screw, 10 ... Press-fitting part, 11 ... Female screw, 20 ... Prepared hole, 2
1 ... Fitting hole, A ... Screw connection part, B ... Press-fit connection part.

Claims (11)

[Claims] 1. A rotating structure comprising a metal rotating body and a metal drive shaft having a melting point higher than that of the rotating body, wherein the rotating body and the drive shaft are integrated by a screw coupling portion and a press-fitting coupling portion. A structure for joining a rotating body and a drive shaft in a rotating structure, which is characterized in that they are joined together. 2. The joint structure of a rotary body and a drive shaft in a rotary structure according to claim 1, wherein the rotary body is made of aluminum or an aluminum alloy material, and the drive shaft is made of steel material. A joint structure of a rotating body and a drive shaft in a rotating structure. 3. The joint structure of a rotary body and a drive shaft in a rotary structure according to claim 1, wherein the screw coupling portion is formed in the rotary body, and a screw hole is formed in the drive shaft and screwed into the pilot hole. The internal diameter of the pilot hole is substantially the same as the effective diameter of the tapping screw, and the tapping screw is screwed into the pilot hole and is plastically deformed to form a female screw in close contact with the tapping screw. A joint structure of a rotating body and a drive shaft in a rotating structure, characterized in that 4. The joining structure for a rotating body and a drive shaft in a rotating structure according to claim 1, 2 or 3, wherein the tapping screw of the drive shaft is threaded in the same direction as the rotating direction of the rotating structure during normal use. A structure for joining a rotating body and a drive shaft in a rotating structure characterized by being provided. 5. The joint structure of a rotary body and a drive shaft in a rotary structure according to claim 1, wherein the screw coupling portion includes a prepared hole formed in the rotary body, and a male screw portion formed in the drive shaft. Is formed by friction stir welding, the inner diameter of the pilot hole and the effective diameter of the male screw portion are substantially the same, and the male screw portion is made of a metal softened to a plastically deformable state by friction heat during friction stir welding. A structure for joining a rotating body and a drive shaft in a rotating structure, which is rotated in a direction of advancing and pushed into the prepared hole. 6. The joint structure of a rotating body and a drive shaft in a rotating structure according to claim 5, wherein the direction of the screw of the male screw portion formed on the drive shaft is the same as the rotating direction of the rotating structure during normal use. A structure for joining a rotating body and a drive shaft in a rotating structure, which is characterized by being threaded into. 7. The joint structure of a rotating body and a drive shaft in a rotating structure according to claim 1, wherein the prepared hole of the rotating body is a press-fitting portion from a joint side end of the drive shaft. The structure for joining a rotating body and a drive shaft in a rotating structure is characterized in that it is a non-penetrating hole having a length substantially equal to the length. 8. The joint structure of a rotating body and a drive shaft in a rotating structure according to claim 1, wherein the joint side end of the drive shaft has a prepared hole and an outer diameter of the rotating body. A joint structure of a rotary body and a drive shaft in a rotary structure, characterized in that a shaft portion having the same or slightly smaller size is formed, and the rotary body is supported at both ends by the shaft portion and the press-fitting portion. 9. A method of joining a rotary body and a drive shaft in a rotary structure, wherein a pilot hole and a fitting hole are formed in the rotary body, and the drive shaft is made of a metal material having a melting point higher than that of the rotary body. A tapping screw and a press-fitting portion, which are threaded in the same direction as the rotation direction of the normal use of the rotary structure, are provided at the end portion on the joint side with the rotating body, and the tapping screw is screwed into the pilot hole, and the press-fitting portion A method for joining a rotary body and a drive shaft in a rotary structure, wherein the rotary body and the drive shaft are integrally joined by press-fitting into the fitting hole. 10. The method for joining a rotary body and a drive shaft in a rotary structure according to claim 9, wherein the effective diameter of the tapping screw of the drive shaft is substantially equal to the inner diameter of the pilot hole of the rotary body, and A method for joining a rotating body and a drive shaft in a rotating structure, wherein a female screw that is in close contact with the tapping screw is formed by screwing the tapping screw and plastically deforming the tapping screw. 11. A method of joining a rotary body and a drive shaft in a rotary structure, wherein a pilot hole and a fitting hole are formed in the rotary body, and the drive shaft is made of a metal material having a melting point higher than that of the rotary body. A male screw portion and a press-fitting portion are provided at the end portion on the joint side with the rotating body, and the male screw portion is rotated while the drive shaft is rotated in a direction of advancing a metal softened to a state where the male screw portion is plastically deformable by frictional heat. By pressing into the pilot hole of the rotating body to friction stir weld the male screw portion and the pilot hole, and press fit the press-fitting portion into the fitting hole to integrally join the rotor and the drive shaft. A method for joining a rotating body and a drive shaft in a rotating structure, comprising: