JP7217598B2 - How to create joint members - Google Patents

Description

TECHNICAL FIELD The present invention relates to a joining member manufacturing method .

Joining using an adhesive enables the miniaturization and higher density of parts compared to joining with screws or rivets. In addition, there are many advantages, such as the ability to join dissimilar materials at room temperature. Therefore, it is attracting attention in various fields such as the electronics industry and the automobile industry. However, when an adhesive is used, there is a problem that the strength varies more than other joining methods (joining means). In particular, variation toward the low-strength side poses a fatal problem, so it is difficult to say that industrial application of adhesion has progressed widely. Therefore, research has been conducted to improve the bonding strength by forming unevenness on the bonding surface by grinding or sandblasting, and its effectiveness has been demonstrated.

That is, conventionally, there has been proposed a method for producing a joining member and a joining structure for the purpose of improving the adhesive strength of the joining member by improving the wettability with the adhesive (Patent Document 1). In this case, as shown in FIGS. 13 and 14, a plurality of long grooves 23 that do not communicate with each other are provided in close proximity to at least one of the bonding surfaces 21a and 22a of the two members 21 and 22 to be bonded. The two members 21 and 22 are joined after forming the unevenness 25 by pressing.

That is, on one bonding surface 21a, an uneven shape with a surface roughness of 25 μm or more and 100 μm or less in terms of arithmetic mean roughness is formed, and an adhesive (adhesive material) is formed between the bonding surfaces of the two members 21 and 22 to be bonded. ) S is interposed for adhesion.

With this configuration, the adhesive material S passes through the plurality of long grooves 23 and spreads over the entire adhesive surface 21a, and the unevenness 25 formed on the adhesive surface 21a increases the contact area with the adhesive member S. be able to. Therefore, the bonding strength of the bonding member obtained by bonding is improved by spreading the bonding material S over the entire bonding surface 21a and improving the wettability between the bonding material S and the bonding surface 21a. .

JP 2010-126682 A

However, in the case of Patent Document 1, unevenness on the order of several to several tens of μm is formed on the entire bonding surface. Accuracy may be adversely affected. In addition, when an adhesive member (adhesive) with a relatively high viscosity is used, it becomes difficult to wet even the recessed portions, and voids, which are starting points of breakage, are generated, resulting in variations in the adhesive strength of the adhesive surface.

As described above, the bonding structure using an adhesive has a problem of large variations in strength compared to other bonding methods. Since variations toward the low-strength side cause a fatal problem, it is difficult to say that the industrial application of structures using adhesives has progressed widely.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a joint member and a method for manufacturing the joint member, which can improve the adhesive holding action and the wetting and spreading property, and can improve the adhesive strength and reduce the variation in the fitting portion. .

A method for manufacturing a joint member according to the present invention is a method for producing a joint member in which a fitting portion between a cylindrical outer peripheral surface and a cylindrical inner peripheral surface is joined via an adhesive. At least one of the cylindrical outer peripheral surface and the cylindrical inner peripheral surface is intermittently provided with concave grooves and a periodic structure of grating-like unevenness having a narrower periodic interval than the groove width in the concave grooves. After providing, an adhesive is interposed between the outer peripheral surface of the cylindrical surface and the inner peripheral surface of the cylindrical surface to bond the outer peripheral surface of the cylindrical surface and the inner peripheral surface of the cylindrical surface. be.

According to the manufacturing method of the joining member of the present invention, the adhesive is held inside the groove, and when the fitting portion is formed (for example, the shaft having the cylindrical outer peripheral surface is replaced with the bush having the cylindrical inner peripheral surface). The adhesive can be evenly retained on the adhesive surface when inserting the adhesive into the adhesive. Furthermore, the surface area is increased by the periodic structure of the grating-like irregularities whose periodic interval is narrower than the groove width, and the adhesive strength can be improved, and the wettability of the adhesive is further improved.

It is preferable that the unevenness of the periodic structure of the grating-shaped unevenness is 50 nm or more and 10 μm or less and the periodic pitch is 10 μm or less. By configuring in this way, the surface area magnification can be increased, and the effect of capillary action becomes remarkable, thereby improving the wettability and wetting and spreading properties of the adhesive. If the unevenness of the periodic structure is less than 50 nm, a sufficient surface area magnification cannot be obtained, and if the unevenness exceeds 10 μm, the adhesive may not wet the recesses. Moreover, when the periodic pitch exceeds 10 μm, the effect of capillary action is weakened.

It is preferable that the groove width of the concave groove is set to be five times or more the periodic pitch of the periodic structure of the grating-like unevenness. By configuring in this way, the adhesive required for adhesion can be held inside the groove. In addition, it is possible to form a plurality of periodic structures inside the groove along the direction in which the groove extends, and the adhesive can spread quickly in the direction in which the groove extends by capillary action.

The depth of the recessed groove may be provided so as to decrease stepwise or continuously along the progressing direction of the groove. With this configuration, pressure is generated in the adhesive when forming the fitting portion, and the pressure can be spread over the entire adhesive surface.

The extending direction of the concave groove may be the axial direction of the fitting portion. By configuring in this way, when forming the fitting portion, the adhesive is likely to wet and spread in the direction of insertion, and the adhesive strength can be improved and variations can be reduced.

The direction of progress of the periodic structure of the grating-like unevenness may be the axial direction of the fitting portion. By configuring in this way, when forming the fitting portion, the adhesive is likely to wet and spread in the direction of insertion, and the adhesive strength can be improved and variations can be reduced.

The periodic structure of grating-like irregularities can be formed in a self-organizing manner by irradiating a linearly polarized laser at an irradiation intensity near the processing threshold and scanning the irradiated portions while overlapping them. By forming in this manner, it is possible to easily obtain a periodic structure having a submicron periodic pitch and unevenness depth that are difficult to obtain by machining. In addition, removal of organic contaminants accompanying laser irradiation provides high wettability to the adhesive.

The concave groove and the periodic structure of the grating-like unevenness can be formed by simultaneous processing. Such simultaneous processing can improve productivity.

The joint member of the present invention is a joint member in which a fitting portion between a cylindrical outer peripheral surface and a cylindrical inner peripheral surface is an adhesive joint portion, and the cylindrical outer peripheral surface and the cylindrical surface shape are joined. On at least one of the bonding surfaces of the inner peripheral surface of the cylindrical surface and the cylindrical An adhesive joint is provided by interposing an adhesive in a fitting portion between the cylindrical inner peripheral surface and the cylindrical outer peripheral surface and the cylindrical inner peripheral surface.

According to the joining member of the present invention, the adhesive is held inside the groove, so that the adhesive can be evenly retained on the bonding surface when forming the fitting portion. Furthermore, the bonding strength can be improved by increasing the surface area due to the periodic structure of the grating-like irregularities whose periodic interval is narrower than the groove width. Further, the improvement in the wettability of the adhesive reduces defects such as voids, and thus the variation in adhesive strength can be reduced.

In the present invention, the bonding strength can be improved by increasing the surface area of the bonding surface, and the wettability of the adhesive is improved, thereby reducing defects such as voids and reducing variations in bonding strength.

1 is a simplified cross-sectional view of a joining member of the present invention; FIG. 1A is a simplified diagram of a shaft in which a periodic structure oriented in the axial direction is formed in concave grooves arranged at a predetermined pitch along the circumferential direction, and FIG. 1 is a simplified diagram of a shaft in which a periodic structure whose orientation direction is the circumferential direction is formed in concave grooves arranged at a predetermined pitch along the shaft; FIG. (a) is a simplified diagram of a shaft in which a periodic structure oriented in the axial direction is formed in grooves arranged at a predetermined pitch along the axial direction; 1 is a simplified diagram of a shaft in which a periodic structure whose orientation direction is the circumferential direction is formed in concave grooves arranged at a predetermined pitch along the shaft; FIG. FIG. 2 shows a periodic structure, where (a) is an enlarged view in which the orientation direction is the axial direction, and (b) is an enlarged view in which the orientation direction is the circumferential direction. 1 is a simplified diagram of a laser surface processing apparatus for forming a periodic structure; FIG. FIG. 4 is a simplified diagram of a state in which a shear tester is used to apply a compressive shear load to the bonding surface between the shaft and the bush. 1 shows a periodic structure, (a) is a simplified diagram of a shaft whose orientation direction is the axial direction, and (b) is a simplified diagram of a shaft whose orientation direction is the circumferential direction. It is a graph showing adhesive strength. FIG. 4 is a graph showing a displacement-load curve; It is an image view of the bonding surface after measuring the bonding strength. FIG. 4 is a graph showing a displacement-load curve; It is a graph chart showing a comparison of adhesion strength and standard deviation. FIG. 10 is a simplified perspective view of a conventional joining member before joining; FIG. 10 is an enlarged cross-sectional view of one member of a conventional joining member;

An embodiment of the present invention will be described below with reference to FIGS. 1 to 12. FIG. FIG. 1 shows a joining member according to the present invention, and this joining member is formed by joining a fitting portion 4 between a cylindrical outer peripheral surface 1a and a cylindrical inner peripheral surface 2a via an adhesive S. is. That is, the joint member includes a shaft 1 as a first member and a short cylindrical body (bush) 2 as a second member into which the shaft 1 is fitted. Between the cylindrical outer peripheral surface 1a of the shaft 1 and the cylindrical inner peripheral surface 2a of the short cylindrical body 2, a fitting portion 4 in which an adhesive S is interposed is formed.

In this case, the first member 1 and the second member 2 may be carbon steel, copper, aluminum, platinum, cemented carbide, or the like, silicon-based ceramics such as silicon carbide or silicon nitride, engineering plastics, or the like. may be

2 and 3, on at least one of the shaft-side adhesive surface S1a constituted by the outer peripheral surface 1a and the adhesive surface S2a constituted by the inner peripheral surface 2a (in this case, the shaft-side adhesive surface S1a). A plurality of grooves 5 are intermittently formed as shown in FIG. In addition, this concave groove may be simply called a groove.

As shown in FIG. 2, the concave grooves 5 may extend in the axial direction at a predetermined pitch along the circumferential direction, or may be formed in a helical shape, as shown in FIG. The cross-sectional shape of the groove 5 may be rectangular or trapezoidal. The grooves 5 extending axially at a predetermined pitch have a groove width of, for example, about 100 μm, a groove pitch of, for example, about 200 μm, and a groove depth of, for example, about 1 μm. The spiral groove 5 may extend clockwise from the lower end or may extend counterclockwise from the lower end. Also in this case, the groove width is, for example, about 100 μm, the groove pitch is, for example, about 200 μm, and the groove depth is, for example, about 1 μm.

As shown in FIGS. 4A and 4B, the periodic structure 6 of the concave groove 5 is formed by alternately arranging minute concave portions 8 and minute convex portions 9 at a predetermined pitch. It is preferable that the height difference of the unevenness of the periodic structure 6 (the height from the bottom of the recess 8 to the top of the protrusion 9) be 50 nm or more and 10 μm or less. Moreover, it is preferable to set the periodic pitch of the periodic structure 6 to 10 μm or less. In this way, the periodic structure 6 is formed so that the apex of the convex portion becomes a non-flat surface and the height changes continuously.

The periodic structure 6 is formed in a self-organizing manner by irradiating a linearly polarized laser with an irradiation intensity near the processing threshold and scanning the irradiated portions while overlapping them. Specifically, a femtosecond laser surface processing apparatus M shown in FIG. 5 is used. A laser (for example, pulse width: 120 fs, center wavelength: 800 nm, repetition frequency: 1 kHz, pulse energy: 0.25 to 400 μJ/pulse) generated by a laser generator 11 (titanium sapphire femtosecond laser generator) is It is folded back toward the workpiece W and guided to the mechanical shutter 13 . At the time of laser irradiation, the mechanical shutter 13 is opened, the laser irradiation intensity can be adjusted by the half-wave plate 14 and the polarization beam splitter 16, the polarization direction is adjusted by the half-wave plate 15, and the condenser lens (focal length : 150 mm) 17 condensed and irradiated the surface of the workpiece W on the XYθ stage 19 . A femtosecond laser is a light source in which energy is compressed in an extremely short time unit of the order of femtosecond (1/1000 trillion second).

By the way, the fitting portion 4 may be any of clearance fit, interference fit, and intermediate spring. As the adhesive S, for example, an anaerobic adhesive can be used. Here, the anaerobic adhesive cures by blocking oxygen by using metal ions when joining metals.

According to the manufacturing method of the joining member of the present invention, the adhesive S is held inside the groove, and when the fitting portion 4 is formed (for example, the shaft 1 having the cylindrical outer peripheral surface 1a is When inserting the bush 2 having the surface 2a), the adhesive S can be evenly retained on the adhesive surface S1a. Furthermore, the surface area is increased by the periodic structure 6 of grating-like irregularities whose periodic interval is narrower than the width of the groove, so that the adhesive strength can be improved, and the wettability of the adhesive S is further improved.

That is, in the present invention, the bonding strength can be improved by increasing the surface area of the bonding surface S1a, and furthermore, defects such as voids are reduced by improving the wettability of the adhesive S, and variations in bonding strength can be reduced. .

The unevenness of the periodic structure 6 of grating-shaped unevenness can be set to be 50 nm or more and 10 μm or less and the periodic pitch can be set to be 10 μm or less. By configuring in this way, the surface area magnification can be increased, and the effect of capillary action becomes remarkable, thereby improving the wettability and wetting and spreading properties of the adhesive. If the unevenness of the periodic structure is less than 50 nm, a sufficient surface area magnification cannot be obtained, and if the unevenness exceeds 10 μm, the adhesive may not wet the recesses. Moreover, when the periodic pitch exceeds 10 μm, the effect of capillary action is weakened.

Further, the groove width of the concave groove 5 can be set to be five times or more the periodic pitch of the periodic structure 6 of the grating-like unevenness. By configuring in this way, the adhesive required for adhesion can be held inside the groove. In addition, it is possible to form a plurality of periodic structures 6 along the direction in which the grooves 5 extend inside the grooves, so that the adhesive S can be quickly spread in the direction in which the grooves extend by capillary action.

Furthermore, the depth of the recessed groove 5 can be provided so as to decrease stepwise or continuously along the extending direction of the groove 5 . With this configuration, when forming the fitting portion 4 (for example, when inserting the shaft 1 having the cylindrical outer peripheral surface 1a into the bush 2 having the cylindrical inner peripheral surface 2a), the adhesive Pressure is generated in S and can be distributed over the entire bonding surface.

The extending direction of the groove 5 can be the axial direction of the fitting portion 4 . By configuring in this way, the adhesive S becomes easier to wet and spread in the inserting direction when forming the fitting portion 4, and it is possible to improve the adhesive strength and reduce variations.

The direction in which the periodic structure 6 of grating-like irregularities develops can be the axial direction of the fitting portion 4 . By configuring in this way, the adhesive S becomes easier to wet and spread in the inserting direction when forming the fitting portion 4, and it is possible to improve the adhesive strength and reduce variations.

The periodic structure 6 of grating-like unevenness can be formed in a self-organizing manner by irradiating a linearly polarized laser at an irradiation intensity near the processing threshold and scanning the irradiated portions while overlapping them. By forming in this manner, it is possible to easily obtain the periodic structure 6 having a submicron periodic pitch and unevenness depth that are difficult to machine. In addition, removal of organic contaminants accompanying laser irradiation provides high wettability to the adhesive.

The grooves 5 and the periodic structure 6 of grating-like unevenness can be formed by a laser surface processing device, and by adjusting the laser irradiation conditions, etc., the grooves 5 and the periodic structure 6 of grating-like unevenness can be simultaneously processed. can be formed in Such simultaneous processing can improve productivity. Of course, the periodic structure 6 may be formed after the groove 5 is formed.

The present invention is not limited to the above-described embodiment, and various modifications are possible. It may be formed on the bush 2 side, which is the second member, or may be formed on both sides of the first member (shaft) and the second member (bush). The shapes of the first member and the second member are not limited to those shown in the drawings. Any one having a shaped inner peripheral surface may be used. Even if the radial dimension and axial length of the outer peripheral surface that constitutes the bonding surface S1a of the first member and the radial dimension and axial length of the inner peripheral surface that constitutes the bonding surface S2a of the second member are It can be set arbitrarily within the configurable range.

The arrangement pitch, groove width, groove depth, groove length, and the like of the grooves 5 can be arbitrarily changed within a range in which the improvement of the adhesive strength, the wettability of the adhesive S, and the like can be achieved. Further, in the embodiment, the depth of the groove 5 is configured to decrease stepwise or continuously along the direction in which the groove 5 extends. It may be configured to decrease stepwise or continuously along the line. In addition, in forming the periodic structure 6, a femtosecond laser, which is a pulse laser, is used in the above embodiment, but a pulse laser such as a picosecond laser or a nanosecond laser can also be used instead of the femtosecond laser. Also, as the adhesive to be used, in the above embodiment, an anaerobic adhesive is used, but other adhesives such as epoxy, acrylic, and urethane can be used.

Joining using an adhesive enables the miniaturization and higher density of parts compared to joining with screws or rivets. In addition, there are many advantages, such as the ability to join dissimilar materials at room temperature. Therefore, it is attracting attention in various fields such as the electronics industry and the automobile industry. However, bonding has a problem that the strength varies more than other joining methods. Variation to the low-strength side poses a fatal problem, so it is difficult to say that industrial application of adhesion has progressed widely. Therefore, research has been conducted to improve the bonding strength by forming unevenness on the bonding surface by grinding or sandblasting, and its effectiveness has been demonstrated. However, due to processing restrictions, unevenness on the order of several to several tens of μm is often formed on the entire bonding surface, which may affect the fitting accuracy of fitting parts. Moreover, an adhesive with a high viscosity cannot wet even the recessed portions, and voids, which are starting points of breakage, are generated, which may increase the variation in adhesive strength.

On the other hand, a grating-like periodic structure 6 having a submicron periodic pitch can be formed by irradiating an ultrashort pulse laser at an energy density near the processing threshold. This periodic structure 6 can contain even smaller roughness of several tens of nanometers or less. As a result, the periodic structure 6 has a small surface roughness and a high surface area magnification. In addition, the removal of organic contaminants due to laser irradiation exhibits high wettability with the adhesive S, so that it is expected that the adhesive strength of fitting parts will be improved and variations will be reduced. Therefore, the periodic structure 6 was patterned as a surface texture on the shaft 1 as the first member that fits and adheres to the bushing 2 as the second member, and the effect on the bonding strength was verified.

Using a shear tester M shown in FIG. 6, a compressive shear load was applied between the contact surfaces S1a and S2a of the shaft 1 and the bush 2 as indicated by arrows, and the bond strength was measured. In this case, the work holder 10 holds the bush 2 . That is, the lower surface 2b of the bush 2 and the lower end surface 1b of the shaft 1 are aligned with each other, and the lower half of the bush 2 is fitted into the holding hole 10a of the work holder 10, so that the lower surface 2b of the bush 2 is aligned. It is in a state of being received by the stepped surface 10a1 of the holding hole 10a. Therefore, the upper half of the shaft 1 protrudes upward from the upper surface 2 c of the bush 2 . At this time, an adhesive S is interposed between the outer peripheral surface 1a of the shaft 1 and the inner peripheral surface 2a of the bush 2 to bond the shaft 1 and the bush 2 together.

The compression speed was set to 1 mm/min, and the displacement and load data of the upper part of the shaft were obtained every 10 ms. A shaft 1 (material: SUJ2, diameter: φ8h5, length: 50,100 mm, Ra 0.4) as a first member and a bush 2 (material: SKS93, inner diameter: φ8H7, length: 15 mm, Ra 1) as a second member .6) An anaerobic adhesive was used and applied only to the shaft side.

As samples, the patterns shown in FIGS. 2(a) and 2(b) and FIGS. 3(a)(b) and the patterns shown in FIGS. 7(a) and 7(b) were manufactured. 7A and 7B, the periodic structure 6 is formed on the outer peripheral surface 1a of the shaft 1 without forming the concave groove 5, and in FIG. 7A, the orientation direction of the periodic structure 6 is the axial direction. , in FIG. 7B, the orientation direction of the periodic structure 6 is the circumferential direction. In this case, the pattern in FIGS. 7A and 7B is called a full pattern, the pattern in FIGS. 2A and 2B is called an intermittent pattern, and the pattern in FIGS. 3A and 3B is called a spiral pattern. . Each periodic structure 6 had a pitch of about 900 nm and a depth of about 250 nm. An unprocessed shaft (without grooves and periodic structure) was also used as a sample.

In the intermittent pattern, periodic structures 6 were formed inside grooves (width 100 μm, depth 1 μm) arranged at regular intervals (200 μm) in the circumferential direction. The spiral pattern formed a periodic structure 6 inside spiral grooves (width 100 μm, depth 1 μm) arranged at regular intervals (200 μm) in the axial direction. The recessed grooves 5 of the intermittent pattern and the spiral pattern and the periodic structure 6 inside the grooves were simultaneously formed by adjusting the laser irradiation conditions.

FIG. 8 shows a comparison of adhesive strength in each processing pattern. Further, FIG. 9 shows displacement-load curves for an intermittent pattern, a spiral pattern, and an unprocessed shaft with a shaft length of 50 mm. Here, since the number of samples is 1 each, the focus is on capturing trends. Focusing on the macro patterns (whole surface pattern, intermittent pattern, spiral pattern), the spiral pattern tended to have unstable adhesive strength (FIG. 8). When the spiral pattern is fitted, it is difficult for the adhesive to wet and spread in the insertion direction, and voids, which are starting points for breakage, are likely to occur, which is considered to be one of the causes of the instability of the adhesive strength. On the other hand, focusing on the direction of the periodic structure 6, the periodic structure 6 in the axial direction exhibited more stable adhesive strength than the periodic structure 6 in the circumferential direction. The periodic structure 6 in the axial direction is considered to be one of the reasons for stabilizing the adhesive strength because the adhesive S tends to wet and spread in the insertion direction when fitting. In addition, in FIG. 9, the periodic structure formed product has a larger slope of the displacement-load curve than the unprocessed shaft, and high adhesive rigidity is obtained. From the viewpoint of wetting and spreading of the adhesive S, the intermittent axial direction cycle, which is a combination of the intermittent pattern and the axial direction periodic structure 6, is thought to be effective in improving the bonding strength and reducing variations.

FIG. 10 shows an image of the bonding surface S1a of the shaft 1 after measuring the bonding strength. FIG. 10(a) shows the grooves 5 and the periodic structure 6 shown in FIG. 2(a) formed, which is called intermittent axial period. 10(c) is a shaft 1 in which the concave groove 5 and the periodic structure 6 are not machined, and this is called an intermittent circumferential cycle. is called raw.

Almost no adhesive S remained on the intermittent circumferential cycle and the unprocessed shaft, and interfacial delamination on the shaft surface was dominant. On the other hand, in the intermittent axial cycle, a cohesive failure region where the adhesive remained on the shaft side was observed.

Next, the number of samples was increased and the characteristics of the intermittent axial period were evaluated. The displacement-load curves obtained from each of the 12 sample raw shafts and intermittent axial cycles are shown in FIG. Three samples (arrows in FIG. 11(a)) of the unprocessed shaft showed an unsteady decrease in adhesion stiffness. On the other hand, in the intermittent axial direction period, the behavior tendency and adhesion stiffness of all samples were almost the same.

A comparison of the bond strength (maximum, minimum, average) and standard deviation for the raw shaft and the intermittent axial cycle is shown in FIG. The intermittent axial cycle was found to improve the bond strength and decrease the standard deviation. The increase in the maximum adhesive strength is about 8%, which is considered to be mainly due to the increase in the adhesive area. The minimum bond strength, which greatly affects bond quality, increased by 39%. It is believed that the increase in the minimum adhesive strength is due to the fact that the intermittent pattern and the periodic structure 6 in the axial direction have an adhesive holding effect and improved wetting and spreadability, thereby reducing defects such as voids and suppressing stress concentration. The raw shaft had an average bond strength of 8848N with a standard deviation of 1488N. In addition, the intermittent axial period had an average bond strength of 10127N and a standard deviation of 1196N.

The coefficient of variation Cv (standard deviation σ/average μ), which is an index of variation, was 0.12 for the intermittent axial cycle, which is 30% lower than 0.17 for the unmachined shaft. When the permissible defect rate is 1/1,000,000 (4.753σ), the load P that can be applied to the bonded portion is calculated from P=μ−4.753σ. , it is presumed that a load 2.5 times or more of the unmachined shaft can be applied to the intermittent axial cycle.

The periodic structure 6 was patterned on the shaft 1 that fits and adheres to the bush 2, and the effect of the periodic structure 6 on the fit-bonding strength was verified. As a result, the following conclusions were obtained.
1. The intermittent axial period is effective for improving the bonding strength.
2. A cohesive failure region is recognized in the periodic structure 6 in the axial direction. On the other hand, the periodic structure in the circumferential direction is mainly interfacial peeling.
3. The intermittent axial cycle is effective in reducing defects caused by improved wetting and in stabilizing adhesive strength by suppressing stress concentration.

1a outer peripheral surface 2a inner peripheral surface S1a, S2a contact surface 4 fitting portion 5 concave groove 6 periodic structure M laser surface processing device S adhesive SA adhesive bonding portion

Claims (1)

A joining member producing method for producing a joining member in which a fitting portion between a cylindrical outer peripheral surface and a cylindrical inner peripheral surface is joined via an adhesive,
In at least one bonding surface of the cylindrical outer peripheral surface and the cylindrical inner peripheral surface, grooves having intermittent intervals in the axial direction and a periodic structure of grating-like unevenness having a periodic interval narrower than the width of the grooves are provided in the grooves. After providing, an adhesive is interposed in the fitting part between the cylindrical outer peripheral surface and the cylindrical inner peripheral surface to bond the cylindrical outer peripheral surface and the cylindrical inner peripheral surface. wherein the unevenness of the periodic structure of grating-like unevenness is 50 nm or more and 10 μm or less and the periodic pitch is 10 μm or less, the groove width of the groove is 5 times or more the periodic pitch of the periodic structure of grating-like unevenness, The depth of the groove is provided so as to decrease stepwise or continuously along the direction in which the groove develops, the direction in which the concave groove develops is defined as the axial direction of the fitting portion, and the direction in which the periodic structure of the grating-like irregularities develops. The axial direction of the fitting part is the axial direction, and the periodic structure of the grating-like unevenness is formed in a self-organizing manner by irradiating a linearly polarized laser with an irradiation intensity near the processing threshold and scanning the irradiated part while overlapping it, A method for producing a joining member, wherein the concave groove and the periodic structure of the grating-like unevenness are formed by simultaneous processing .

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