JP2005125344A - Friction welded structure and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction welded structure having a high joining strength, and to provide a friction welding method for manufacturing the structure. <P>SOLUTION: The friction welded structure is obtained by relatively rotating a first and a second shaft-like member 1, 2 and friction-welding the first shaft-like member 1 into the hole of the second. A groove 112 having inclination relative to the center axis lines Z1, Z2 of the shaft-like members 1, 2 is provided in either one of the shaft surface of the first shaft-like member 1 or the hole surface of the second 2. Accordingly, in friction welding of both shaft-like members 1, 2, the material melted by the frictional heat is promoted to move, through the presence of the inclined groove 112, in the center axial direction of the shaft-like members, resulting in the acceleration of the plastic flow action of the melted material. As a result, inter-metallic solid-phase welding incidental to uniform diffusion is realized, with the joining strength increased between the shaft-like members. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a friction welding structure in which two members are relatively rotated and friction bonded, and a friction welding method thereof.

As a prior art, there is a friction welding method disclosed in Patent Document 1. This is because the shaft is pressed against the end face of a member having a hole that does not penetrate, and a joining burr generated at this time is introduced into the hole and the spline provided on the outer periphery of the shaft, so as to have a so-called key function. Is.
Japanese Patent Laid-Open No. 2001-1167

  However, with this method, even if the burr travels along the spline and enters the axial direction, strong bonding is not established.

  An object of this invention is to provide the friction welding structure with high joint strength in view of the said point. Another object of the present invention is to provide a friction welding method for manufacturing a friction welding structure having high bonding strength.

  In order to achieve the above object, according to the first aspect of the present invention, the first shaft member (1) and the hole (21, 21a) into which the first shaft member (1) is inserted are mainly used. The second shaft-shaped member (2) is formed, and the two shaft-shaped members (1, 2) are relatively rotated to rotate the holes (21, 21a) of the second shaft-shaped member (2). Is a friction welding structure formed by friction-joining the first shaft-like member (1) to the shaft surface of the first shaft-like member (1) and the hole (21 of the second shaft-like member (2)). 21a) has a linear portion (111) having an inclination with respect to the central axis (Z1, Z2) of the shaft-like member (1, 2) on any one of the surfaces of 21a).

  According to this, when the two shaft-shaped members are friction-joined, the material melted by the frictional heat is accelerated by the movement of the shaft-shaped member in the central axis direction due to the presence of the inclined linear portion. Since the plastic flow action is promoted, uniform solid-phase joining is realized and the joining strength of both shaft-like members is increased.

  As described in the second aspect of the invention, the plastic flow action can be further promoted by forming the linear portion (111) into a groove or a convex shape.

  In the invention described in claim 3, the linear portion (111) is formed on the side of the first shaft member (1) and the second shaft member (2) having a relatively high melting point. It is characterized by that.

  As described above, by forming the linear portion on the side having a high melting point, the above-described effects due to the linear portion can be effectively exhibited during friction welding.

  As in the invention described in claim 4, the first shaft-like member (1) can be made of an iron-based material, and the second shaft-like member (2) can be made of an aluminum material.

  The invention according to claim 5 is characterized in that the linear portion (111) is a groove, and the linear portion (111) is formed on the first shaft member (1).

  Thus, it is optimal in terms of processing to form a linear portion made of a groove in the first shaft member. Thereby, the molten material is filled in the groove, and an anchor effect can be exhibited.

  In the invention according to claim 6, the linear portion (111) is within a range of being inserted into the hole (21, 21a) of the second shaft-shaped member (2) in the first shaft-shaped member (1). It is characterized by being formed.

  It is important that the range in which the first shaft-like member is inserted into the hole is joined. According to the invention of claim 6, since the linear portion (111) is formed in the range, Strength increases.

  In the invention according to claim 7, the linear portion (111) is in a range of being inserted into the hole (21, 21a) of the second shaft-shaped member (2) in the first shaft-shaped member (1). It is formed over the whole.

  According to this, since the linear portion is formed over the entire insertion range, a part of the molten material surely plastically flows over the entire insertion range, and the joint strength is improved.

  In invention of Claim 8, the area | region inserted in the hole (21, 21a) of the 2nd shaft-shaped member (2) in the 1st shaft-shaped member (1), and the 2nd shaft-shaped member One of the holes (21, 21a) of (2) is characterized in that one is tapered and the other is straight.

  When the shaft-like members are both tapered, they are solid, so that it is easy to cause an increase in work driving torque and intense chatter noise during friction joining. On the other hand, according to the eighth aspect of the present invention, since there is no solid contact, it is possible to reduce the workpiece driving torque and eliminate the vibration noise when the friction bonding is performed.

  In the invention according to claim 9, the first shaft member (1) and the second shaft formed around the hole (21, 21a) into which the first shaft member (1) is inserted. The first shaft-shaped member (2) and the shaft-shaped members (1, 2) are relatively rotated so that the holes (21, 21a) of the second shaft-shaped member (2) are rotated. A friction welding method of a friction welding structure for friction welding (1), wherein the shaft surface of the first shaft member (1) and the holes (21, 21a) of the second shaft member (2) are provided. A linear portion forming step of forming a linear portion (111) having an inclination with respect to the central axis (Z1, Z2) of the shaft-like member on either one of the surfaces, and both axes after the linear portion forming step And a friction joining step of friction-joining both shaft-like members (1, 2) by relatively rotating the shaped members (1, 2).

  According to this, the same effect as that of the invention of claim 1 can be obtained.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described. 1 is a perspective view after friction welding of the friction welding structure according to the first embodiment, FIG. 2 is a cross-sectional view of the friction welding structure of FIG. 1, and FIG. 3A is an external view of the shaft before friction welding, FIG. 3B is a cross-sectional view taken along line AA in FIG. 3A, and FIG. 4 is a cross-sectional view of the screw before friction welding.

  As shown in FIGS. 1 and 2, a steel shaft 1 and an aluminum screw 2 are friction-joined to form a screw rotor as a friction welding structure. The shaft 1 corresponds to the first shaft member of the present invention, and the screw 2 corresponds to the second shaft member of the present invention.

  As shown in FIG. 3, the shaft 1 includes a straight-shaped joining shaft portion 11 having a constant outer diameter, and first and second shaft portions 12 and 13 formed on both ends of the joining shaft portion 11. Have. The first and second shaft portions 13 have a straight shape with a constant outer diameter and a smaller diameter than the joint shaft portion 11.

  In addition, a plurality of grooves 111 are formed on the outer peripheral surface of the joining shaft portion 11, and both end corner portions 112 of the joining shaft portion 11 have an R shape. More specifically, the groove 111 has an inclination θ of, for example, about 3 ° with respect to the central axis Z1 of the shaft 1, and three grooves 111 are formed, for example, at 120 ° intervals along the circumferential direction of the shaft 1. . Further, the length of the groove 111 in the direction of the central axis Z1 is substantially the same as the length of the hole 21 of the screw 2 to be described later, and as shown in FIG. 2, in the state where the shaft 1 and the screw 2 are joined, The groove 111 is positioned in the entire axial range of the hole 21 of the screw 2. The groove 111 corresponds to the linear portion of the present invention, and the step of forming the groove 111 corresponds to the linear portion forming step of the present invention.

  As shown in FIG. 4, a tapered hole 21 extending in the direction of the central axis Z <b> 2 of the screw 2 is formed at the center of the screw 2. The dimension of the maximum inner diameter portion of the hole portion 21 is set larger than the outer diameter of the joining shaft portion 11 of the shaft 1, while the dimension of the minimum inner diameter portion of the hole portion 21 is the outer diameter of the joining shaft portion 11 of the shaft 1. Is set smaller than.

  The shaft 1 and the screw 2 formed as shown in FIGS. 3 and 4 are integrated by friction joining described below.

  That is, the shaft 1 is inserted into the hole 21 of the screw 2 so that one corner 112 of the joining shaft 11 of the shaft 1 is brought into contact with the hole 21 of the screw 2 and the shaft 1 is rotated (friction joining step). ). Due to the relative rotation of the shaft 1 and the screw 2, frictional heat is generated at the contact portion between the shaft 1 and the screw 2. Since the melting point of the screw 2 is lower than that of the shaft 1, the inner surface of the hole 21 of the screw 2 is melted by the frictional heat. The shaft 1 penetrates into the hole 21 while melting the inner surface of the hole 21 of the screw 2.

  A part of the melted material enters the vicinity of one end of the groove 111 of the shaft 1. And since the groove | channel 111 has inclination (theta) with respect to the central axis Z1 of the shaft 1, the molten material which entered the groove | channel 111 is given a thrust with rotation of the shaft 1, and the one end side vicinity of the groove | channel 111 is provided. The molten material that has entered is scraped up to the other end of the groove 111.

  Thus, the plastic flow action of the molten material in the direction of the central axes Z1 and Z2 is promoted by the groove 111 having the inclination θ, and between the joint shaft portion 11 of the shaft 1 and the hole portion 21 of the screw 2 in the lifting process. The molten material is sufficiently fluidized and filled, and the shaft 1 and the screw 2 are firmly joined by intermetallic solid-phase joining accompanying uniform diffusion.

  Further, since the groove 111 is positioned in the entire range of the hole portion 21 in the axial direction, a part of the molten material surely plastically flows over the entire range in which the shaft 1 is inserted, and the bonding strength Will improve.

  In addition, as a result of filling the groove 111 with the molten material, the material in the groove 111 exhibits an anchor effect after cooling, and the joint between the shaft 1 and the screw 2 is further strengthened.

  Moreover, since the contact part of the straight-shaped joining shaft part 11 and the taper-shaped hole part 21 does not become solid at the time of friction joining, the workpiece drive torque and chatter noise at the time of friction joining can be reduced.

  In addition, since both end corners 112 of the joint shaft 11 have an R shape, the resistance when the shaft 1 and the screw 2 are brought into contact with each other for relative rotation is reduced, and plastic flow is facilitated.

(Second Embodiment)
A second embodiment of the present invention will be described. 5A is an external view of a shaft before friction welding of the friction welding structure according to the second embodiment, FIG. 5B is a cross-sectional view taken along line BB in FIG. 5A, and FIG. It is sectional drawing of the screw before friction joining. In addition, the same code | symbol is attached | subjected to the same or equivalent part as 1st Embodiment, and the description is abbreviate | omitted.

  In this embodiment, as shown in FIG. 5, the joining shaft portion 11a of the shaft 1 is tapered, while the hole portion 21a of the screw 2 is formed in a straight shape with a constant inner diameter as shown in FIG. . The dimension of the maximum outer diameter portion of the joint shaft portion 11a is set larger than the inner diameter of the hole portion 21a, while the dimension of the minimum outer diameter portion of the joint shaft portion 11a is set smaller than the inner diameter of the hole portion 21a. Has been.

  The shaft 1 and the screw 2 formed as shown in FIGS. 5 and 6 are integrated by friction welding described below.

  That is, the shaft 1 is inserted into the hole portion 21 a of the screw 2, the outer peripheral surface of the joint shaft portion 11 a of the shaft 1 is brought into contact with the one end side corner portion of the hole portion 21 a of the screw 2, and the shaft 1 is rotated. Due to the relative rotation of the shaft 1 and the screw 2, frictional heat is generated at the contact portion between the shaft 1 and the screw 2. The shaft 1 enters the hole 21 while melting the hole 21a of the screw 2 by the frictional heat.

  Hereinafter, as in the first embodiment, a part of the melted material enters the vicinity of one end of the groove 111 of the shaft 1, and the plastic flow action of the molten material in the central axis Z1 and Z2 directions by the groove 111 having the inclination θ. The molten material is sufficiently flowed and filled between the joint shaft portion 11a of the shaft 1 and the hole portion 21a of the screw 2 in the lifting process, so that the shaft 1 and the screw 2 have a uniform diffusion between the metals. Solidly bonded by solid phase bonding.

  Moreover, since the contact part of the taper-shaped joining shaft part 11a and the straight-shaped hole part 21a does not become solid at the time of friction joining, the workpiece drive torque and chatter noise at the time of friction joining can be reduced.

  Next, the results of experiments based on this second embodiment will be described.

  5A and 5B, the dimensions of the shaft 1 are as follows. The unit of each dimension is (mm).

Total length of the shaft 1: 100
Joint shaft length: 40
First shaft length × diameter: 35 × 10
Second shaft length × diameter: 25 × 10
Tip of second shaft: Arc of R2 Taper gradient of joint shaft: 1/20
Diameter of the left corner of the joint shaft: 10
Groove inclination angle: 3 °
Groove depth: R0.5
In FIG. 6, the dimensions of the screw 2 are as follows.

Screw total length x diameter: 36 x 36
Hole diameter: 9.5
The shaft 1 having the above configuration is rotated at a high speed of 3200 rpm, and the shaft 1 is moved at a moving speed (friction speed) of 60 mm / min with the tip of the second shaft portion 13 being the tip of the hole 21 a of the screw 2. With a pressing pressure (friction pressure) of 60 kN.
The diameter of the second shaft portion 13 of the shaft 1 is 10 mm and is larger than the diameter 9.5 mm of the hole portion 21a of the screw 2, but the tip of the second shaft portion 13 has an R shape of R2 mm. The tip contacts the inside of the hole 21a of the shaft 1 and generates frictional heat based on the friction speed and friction pressure.

When the hole 21a of the screw 2 is melted by this frictional heat and the plastic flow of aluminum as the material of the screw 2 starts, the pressing pressure (joining pressure) on the shaft 1 is lowered to 5 kN, and the moving speed of the shaft 1 (Joint strength) is increased to 900 mm / min.
Then, when the second shaft portion 13 of the shaft 1 is exposed from the tip of the hole portion 21a of the screw 2, the rotation of the shaft 1 is stopped.

  From the above, it was recognized that the joining shaft portion of the shaft 1 was firmly joined to the hole portion 1a of the screw 2.

(Other embodiments)
In each of the above embodiments, the groove 111 is provided in the joint shaft portions 11 and 11a of the shaft 1, but the groove 111 may be provided in the hole portions 21 and 21a of the screw 2.

  In each of the above embodiments, one of the joining shaft portion of the shaft 1 and the hole portion of the screw 2 is tapered and the other is straight, but both may be tapered. However, in this case, it is necessary to change both taper angles. That is, if the taper angle is the same, the contact portion between the joint shaft portion and the hole portion becomes a solid contact during friction welding, and the shaft 1 may be twisted and broken before the plastic flow is started by frictional heat. However, the problem can be avoided by changing the taper angle between the two.

  In each of the above embodiments, the grooves 111 are provided as the linear portions. However, a plurality of convex shapes (corresponding to the linear portions) may be provided instead of the grooves 111. In this case, the molten material enters between adjacent convex shapes. And the convex shape exhibits the same function as the groove 111, that is, the function of imparting thrust to the molten material to promote the plastic flow action of the molten material in the central axis Z1 and Z2 directions.

  Moreover, the cross-sectional shape of the groove | channel 111 in each said embodiment can be selected according to the material and shape of the shaft 1 or the screw 2, such as a quadrangle, V shape, U shape, and a half moon shape. Similarly, the number and arrangement of the grooves 111 can be selected according to the material and shape of the shaft 1 and the screw 2. Moreover, although the groove | channel 111 was formed continuously over the precursor of the joining shaft parts 11 and 11a of the screw 2, of course, you may form in an intermittently discontinuous aspect. Of course, this can also be applied to the above-described convex shape.

  In each of the above embodiments, the corners 112 of the joint shafts 11 and 11a are rounded, but the corners 112 may be chamfered.

  The present invention can also be applied to a friction welding structure other than a screw rotor.

  In addition, the screw 2 of each said embodiment can be processed by rolling, for example. As the rolling die used in that case, if a rolling die in which a plurality of (four in this example) dies 3 are stacked as shown in FIG. 7 is used, it is easy to process a tooth mold with a large undercut or lead. It is. Incidentally, the plurality of dies 3 are integrated by bolts 4.

  Moreover, in each said embodiment, although the through-hole which both ends opened was used as a hole part in the screw 2 which is a 2nd shaft-shaped member, of course, the hole part which one end opened and the other end closed may be used. is there.

  Further, in each of the above embodiments, the groove 111 for scraping the plastic fluid material by the rotation of the shaft 1 as the first shaft member is a plurality of grooves having a predetermined inclination. Of course.

  Furthermore, in each said embodiment, although the shaft 1 which is a 1st axial member was made into an iron-type material, and the screw 2 which was the 2nd axial member was made into an aluminum material, it is not limited to these materials, Basically, various combinations of materials can be applied to the present invention as long as they are a combination of materials capable of friction welding.

It is a perspective view after the friction welding of the friction welding structure which concerns on 1st Embodiment of this invention. It is sectional drawing of the friction welding structure of FIG. (A) is an external view of the shaft before friction joining, (b) is sectional drawing which follows the AA line of (a). It is sectional drawing of the screw before friction joining. (A) is an external view of the shaft before the friction welding of the friction welding structure according to the second embodiment, and (b) is a sectional view taken along line BB in (a). It is sectional drawing of the screw before friction joining. It is a typical figure of the rolling die used for processing of a screw.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Shaft (1st axial member), 2 ... Screw (2nd axial member), 21 and 21a ... Hole part, 111 ... Groove (linear part), Z1, Z2 ... Central axis.

Claims (9)

The first shaft-shaped member (1) and the second shaft-shaped member (2) formed around the holes (21, 21a) into which the first shaft-shaped member (1) is inserted are provided. Then, the first shaft-shaped member (1) is inserted into the holes (21, 21a) of the second shaft-shaped member (2) by relatively rotating the shaft-shaped members (1, 2). It is a friction welding structure formed by friction welding,
Either the shaft surface of the first shaft-shaped member (1) or the surface of the hole (21, 21a) of the second shaft-shaped member (2) has the shaft-shaped member (1, 2). A friction welding structure characterized by having a linear portion (111) having an inclination with respect to the central axis (Z1, Z2). The friction welding structure according to claim 1, wherein the linear portion (111) is a groove or a convex shape. The said linear part (111) is formed in the side with comparatively high melting | fusing point among said 1st shaft-shaped member (1) and said 2nd shaft-shaped member (2), It is characterized by the above-mentioned. Item 3. The friction welding structure according to Item 2. The friction welding structure according to claim 3, wherein the first shaft-like member (1) is made of an iron-based material, and the second shaft-like member (2) is made of an aluminum material. The linear part (111) is a groove, and the linear part (111) is formed on the first shaft-like member (1). 2. The friction welding structure according to 1. The said linear part (111) is formed in the range inserted in the said hole part (21, 21a) of the said 2nd axial member (2) in the said 1st axial member (1). The friction welding structure according to claim 5. The said linear part (111) is formed over the whole range inserted in the said hole part (21, 21a) of the 2nd axial member (2) in the said 1st axial member (1). The friction welding structure according to claim 6, wherein the friction welding structure is provided. The region inserted into the hole (21, 21a) of the second shaft-shaped member (2) in the first shaft-shaped member (1), and the region of the second shaft-shaped member (2) The friction welding structure according to any one of claims 1 to 7, wherein one of the holes (21, 21a) is tapered and the other is straight. The first shaft-shaped member (1) and the second shaft-shaped member (2) formed around the holes (21, 21a) into which the first shaft-shaped member (1) is inserted are provided. Then, the first shaft-shaped member (1) is inserted into the holes (21, 21a) of the second shaft-shaped member (2) by relatively rotating the shaft-shaped members (1, 2). A friction welding method of a friction welding structure for friction welding,
One of the axial surface of the first shaft member (1) and the surface of the hole (21, 21a) of the second shaft member (2) has a central axis (Z1, A linear portion forming step of forming a linear portion (111) having an inclination with respect to Z2);
And a friction joining step of frictionally joining the two shaft-shaped members (1, 2) by relatively rotating the shaft-shaped members (1, 2) after the linear portion forming step. Friction welding method for friction welding structure.

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