JP6802695B2 - Pulley joining method and joining structure - Google Patents

Description

The present invention relates to a joining method and a joining structure of a pulley that joins a fixed side pulley or a movable side pulley and a shaft member by laser welding.

Conventionally, in plasma welding, the processing time is long in order to secure the penetration depth, and as a result, heat is applied in a wide range, so that there is a problem that the dimensional accuracy after assembly deteriorates due to thermal strain. ..

In order to solve this problem, the application of laser welding, which enables local welding, has recently been studied.

Japanese Unexamined Patent Publication No. 2009-1977

However, when laser welding is applied to weld a circular joint, there are the following problems. That is, for example, as shown in FIG. 13, when the shaft member 101 is fitted into the fitting hole 103 of the disk member 102 and then the shaft member 101 is supported by a jig (not shown) for welding. With the jig and the shaft member 101 loose (for example, tilted from the vertical direction), laser welding is performed by irradiating laser light along the edge of the fitting hole 103, and the final product is annular. There is a problem that the welded portion 104 of the above is eccentric from the center of the pulley, resulting in poor welding due to misalignment. If an attempt is made to prevent such misalignment and use a large spot diameter so as not to cause misalignment, a large amount of power is required as a laser irradiation device, a large energy loss occurs, and the device is also large. There was another issue, such as becoming a laser.

Therefore, an object of the present invention is to provide a joining method and a joining structure of a pulley that can prevent welding defects due to misalignment with respect to a circular joining portion in order to solve the above problems.

In order to achieve the above object, the present invention is configured as follows.

According to one aspect of the present invention, one of the pulley and the shaft member for torque transmission of the vehicle is a high heat transfer member and the other is a low heat transfer member.
A shaft member is fitted into the fitting hole of the pulley , and the shaft member is fitted.
Then, in the annular joint region including the circular joint edge between the shaft member and the fitting hole, the length of the scanning path in the low heat transfer member is larger than the length of the scanning path in the high heat transfer member. by irradiating Les Za light along a scanning path which intersects a plurality of times at intervals in the circumferential direction of the joint edges while longer is, the laser welding portion of the strip of bead overlapping the joint edge of the circular Provided is a method for joining a pulley, which is formed and the pulley and the shaft member are joined and fixed.

Further, according to another aspect of the present invention, one of the pulley and the shaft member for torque transmission of the vehicle is a high heat transfer member and the other is a low heat transfer member.
In a state where the shaft member is fitted into the fitting hole of the pulley , the length of the scanning path in the low heat transfer member is longer than the length of the scanning path in the high heat transfer member, and the shaft member and the said. The pulley and the shaft member are joined and fixed at a laser welded portion of a band-shaped bead having a laser scanning mark intersecting the circular joint edge with the fitting hole and formed so as to overlap the joint edge. Provided is a welded structure of the pulley.

According to the above aspect of the present invention, it is possible to irradiate a laser beam along a scanning path that intersects a circular joint edge to form a laser welded portion of a band-shaped bead that overlaps the joint edge, and is circular. It is possible to prevent welding defects due to misalignment of the joints.

Top view of the joint structure of the pulley according to the embodiment of the present invention. Cross-sectional side view of the joint structure of FIG. 1A Explanatory drawing of joining method of pulley which concerns on embodiment of this invention Explanatory drawing of the scanning path of the pulley joining method concerning FIG. Explanatory drawing of the bead of the pulley joining method according to FIG. Partially enlarged explanatory view of the scanning path of the pulley joining method according to FIG. 3A. Enlarged view showing a photograph of laser scanning marks Explanatory drawing showing a scanning path, a photograph of a bead in a flat state, and a photograph of a blended state when the lap ratio is -17.2% on the left and 6.2% on the right in the pulley joining method. Explanatory drawing when the heat transfer properties of two members with the joint edge as a boundary are equal in the pulley joining method. Explanatory drawing when the heat transfer property of two members with a joint edge as a boundary is different in the pulley joining method Schematic explanatory view of the enlarged cross section of the bead in the method of joining the pulley. Explanatory drawing of the joining method of the pulley Schematic diagram of one example of partially scanning a circular joint edge in a pulley joining method. Schematic diagram of another example of partially scanning a circular joint edge in a pulley joining method. Explanatory drawing of joining method of pulley which concerns on modification of said embodiment Explanatory drawing of the joint method of the pulley which concerns on the 2nd modification of the said Embodiment Explanatory drawing of the joint method of the pulley which concerns on the 3rd modification of the said Embodiment Explanatory drawing of joining method of pulley which concerns on 4th modification of said embodiment Explanatory drawing of joining method of pulley which concerns on 5th modification of said embodiment Explanatory drawing of the joint method of the pulley which concerns on the 6th modification of the said Embodiment Explanatory drawing of joining method of pulley which concerns on 7th modification of said embodiment Explanatory drawing of joining method of pulley which concerns on 8th modification of said embodiment Explanatory drawing when welding to a circular joint by applying conventional laser welding

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment)
As shown in FIGS. 1A to 2, the pulley joining method and joining structure according to the embodiment of the present invention are small pulleys for vehicle torque transmission, for example, for automobiles or motorcycles for belt-type CVTs. The end portion of the shaft member 1 is press-fitted into the fitting hole 2a of the tubular portion 2b of the fixed side or movable side pulley 2 such as a pulley, and the peripheral end surface of the fitting hole 2a and the end surface of the end portion of the shaft member 1 are formed. After fitting so as to be flush with each other, laser welding is performed on the circular joint edge 3 between the outer peripheral edge of the end portion of the shaft member 1 and the inner peripheral edge of the fitting hole 2a.

As shown in FIGS. 3A and 3B, in laser welding, the entire circumference of the circular joint edge 3 in the circumferential direction or a part thereof is overlapped with the joint edge 3, for example, in the annular joint region 7 having a predetermined width. A band-shaped bead 5 having a laser scanning mark is formed as a laser welded portion by irradiating the laser beam 9 while scanning along a zigzag-shaped scanning path 8 that intersects the joint edge 3 a plurality of times at intervals. The annular joining region 7 may be, for example, an annular region having a constant width or a region having a partially different width. The laser scanning marks are linear marks extending substantially radially on the surface of the bead 5.

Specifically, in the above-described embodiment, as shown in FIG. 3A, an annular joint region 7 is set as a bead forming region including the joint edge 3. As an example of the annular joint region 7, the width dimension in the radial direction is set to be constant at 1.5 mm, and the joint edge 3 is set so as to be located near the center of the width dimension in the radial direction. The width dimension of the annular joint region 7 is an example, and can be appropriately set depending on the size and material of the object to be joined, the required joint strength, and the like, but for automobiles or motorcycles. In the joining of the small pulley 2 and the shaft member 1 as described above, a gap exceeding the spot diameter of the laser beam 9 usually does not occur at the joining edge 3, so if it is at least larger than the spot diameter, the joining Defects can be prevented. However, if the width dimension of the joint region 7 is too large, the processing time will increase. Therefore, it is desirable that the width dimension of the joint region 7 is substantially 2 to 3 times the spot diameter.
Within the annular junction region 7, the laser irradiation device 11 continuously scans the laser beam 9 along the zigzag-shaped scanning path 8 intersecting the junction edge 3.

As shown in FIG. 3C, the scanning path 8 of the zigzag-shaped laser beam 9 constitutes a V-shaped 8c composed of a first shaded portion 8a and a second shaded portion 8b, and the V-shaped shape 8c is formed. For example, it is arranged continuously along the joint edge 3 and drawn with a single stroke to perform V-shaped weaving so that continuous welding can be performed. The first shaded portion 8a is a path that intersects the joint edge 3 at the intermediate portion thereof, intersects the tangent line 8e indicated by the solid line at the intersection 8d at a predetermined angle θ1, and goes from the inside to the outside. The second shaded portion 8b is a path that intersects the joint edge 3 at the intermediate portion thereof, and at the intersection 8f, is inclined from the outside to the inside with respect to the tangent line 8g indicated by the dotted line at a predetermined angle θ2. The outer end of the first shaded portion 8a and the outer end of the second shaded portion 8b are connected to each other to form a V-shaped 8c. As an example, the distance W2 between the intersection 8d and the intersection 8f on the joint edge 3 may be constant or variable. Further, the predetermined angles θ1 and θ2 may be constant or different from each other. When connecting adjacent V-shaped 8c to each other, for example, the second shaded portion 8b and the first shaded portion 8a connected to the second shaded portion 8b form the same V-shaped shape 8h upside down. , The V-shape is not limited to the same V-shape, and may be a V-shape having a different shape.

The portion irradiated with the laser beam 9 along the zigzag-shaped scanning path 8 is partially melted by the bonding heat from the start of the zigzag-shaped formation, and the zigzag-shaped distinction does not remain clearly. As shown by the diagonal lines in FIG. 3B and the photograph in FIG. 3D, they are fused to form one thick annular band-shaped bead 5 as a whole. As is clearly shown in FIG. 3D, when the laser beam 9 is irradiated along the zigzag-shaped scanning path 8, the laser scanning marks are substantially diametered on the surface of the bead 5 along the zigzag-shaped trajectory. It remains as a linear trace extending in the direction.

The band-shaped bead 5 overlaps the circular joint edge 3 formed by the fitting hole 2a of the tubular portion 2b of the pulley 2 and the end portion of the shaft member 1, and has a penetration depth from the end portion of the shaft member 1. It is partially formed in the longitudinal direction. As a more specific example, as shown in FIGS. 3B and 4A, the bead 5 has an inner thin joint inner edge portion 5a, an outer thin joint outer edge portion 5b, and a wide annular joint body portion in the middle. It is roughly configured with 5c. The thin joint inner edge portion 5a and the thin joint outer edge portion 5b are regions that are thermally metamorphosed by heat input to the joint main body portion 5c, respectively. The annular joint body 5c is formed by being sandwiched between two thin joint inner edges 5a and a thin joint outer edge 5b, and the circular joint edges 3 are overlapped with a constant width and partially to a desired penetration depth. A penetration 6 (see FIG. 4A) is formed and welded. As an example, when the axial length of the tubular portion 2b is 5 mm and the bead 5 is partially formed from the end portion of the shaft member 1 in the penetration depth direction, the depth of the partial penetration 6 is formed. The length is 1 mm, and less than 50% of the axial length of the tubular portion 2b is the depth of the partial penetration 6. Further, the thin joint inner edge portion 5a and the thin joint outer edge portion 5b are not formed to be as deep as the annular joint main body portion 5c, respectively. Here, the laser welded portion is configured to weld only a part in the welding depth direction on the fitting surface (joining main body portion 5c) of the fitting hole 2a of the tubular portion 2b of the pulley 2. On the other hand, there is a technique related to complete penetration welding in which a laser is weaved to melt each of the two members over the entire length in the welding depth direction and the members are prevented from melting down by the backing. In welding, it was necessary to apply energy to both sides of the joint edge of the two members. However, in the joining method of the present invention, it is not necessary to apply energy to both sides of the joining edge in this way.

Further, FIG. 4D is a schematic explanatory view of an enlarged cross section of the bead 5 when the lap ratio of FIG. 4A is 6.2%. As a macroscopic explanation of the laser scanning marks, the surface of the laser welded portion of the bead 5 is formed by alternately arranging groove portions 5d and raised portions 5e extending in a direction intersecting the joint edge 3 so as to overlap the joint edge 3. The pulley 2 and the shaft member 1 are joined and fixed. Further, the laser welded portion is an adjacent portion on the inner peripheral side of the pulley 2 with respect to the groove portion 5d and the raised portion 5e (inner thin joint inner edge portion 5a) and an adjacent portion on the outer peripheral side of the pulley 2 (outer outer thin joint outer edge portion 5b). Each of them has a heat-transformed portion.

In this way, by continuously scanning the laser beam 9 in a zigzag shape so as to intersect the junction edge 3, a laser scanning mark is provided in, for example, an annular junction region 7 having a predetermined width overlapping the junction edge 3. By forming the band-shaped bead 5 as a laser welded portion, the pulley 2 and the shaft member 1 can be stably joined and fixed.

As a result, it is possible to prevent welding defects due to misalignment of the joint edge 3 as a circular joint portion. That is, the occurrence of misalignment can be prevented by crossing the scanning direction of the laser beam 9 with the junction edge 3 instead of scanning the laser beam 9 along the circular junction edge 3. Further, for example, an annular joint region 7 having a predetermined width including the circular joint edge 3 is set, and a band-shaped bead 5 overlapping the joint edge 3 is formed in the joint region 7 as a laser welded portion. Within, it is permissible that the position of the band-shaped bead 5 is slightly displaced, and as a whole, as long as the band-shaped bead 5 is formed in the joint region 7, the occurrence of misalignment can be prevented.

As an example of the scanning path 8, as shown in FIG. 3A, the scanning path 8 is formed in a zigzag manner while scanning an equal distance inside and outside the circular junction edge 3, and the interval W2 at which the circular junction edge 3 intersects is , As an example, it is even. In this way, the variation in the partially formed penetration depth can be reduced. The intersection interval W2 is not limited to equal intervals, and the intervals may be different. In such a case, the processing time can be shortened. The reason is that the dense portion and the sparse portion of the crossing interval W2 are arranged alternately, so that the processing time can be shortened in the sparse portion while ensuring the joint strength in the dense portion.

Next, a method of joining the pulleys will be described.

First, the end portion of the shaft member 1 is fitted into the fitting hole 2a of the pulley 2. As an example, the end portion of the shaft member 1 is fitted into the fitting hole 2a with almost no gap, and a circular linear joint edge 3 is formed.

Next, as shown in FIG. 2, another end side of the shaft member 1 is supported by the tubular jig 10. At this time, in order to efficiently set the shaft member 1 on the jig 10 before welding in a short time, the center of the circle of the joint region 7 (corresponding to the bead 5 after welding) and the circular shape of the pulley 2. The misalignment (eccentricity) with the center is intentionally allowed. As an example, a misalignment (eccentricity) (for example, 0.3 mm) larger than the spot diameter (for example, 0.2 mm) is generated.

Next, the laser irradiation device 11 is used to perform laser welding along a predetermined scanning path 8. That is, in the annular joint region 7 including the circular joint edge 3 between the end portion of the shaft member 1 and the fitting hole 2a, the joint edge 3 is intersected a plurality of times with an interval W2 in the circumferential direction. A laser beam 9 is irradiated along the scanning path 8 to form a band-shaped bead 5, and the pulley 2 and the shaft member 1 are joined and fixed.

Here, the spot diameter at the time of laser welding, the laser scanning speed, and the laser output can be set according to the penetration depth. For example, in the example of the pulley 2 and the shaft member 1, it is generally required to satisfy a penetration depth of at least 0.1 mm or more. Therefore, as an example, the spot diameter is set to 30 μm or more and 200 μm or less, and the laser scanning speed is set. Can be 200 mm / s or more, and the laser output can be 450 W or less. Since the smaller the spot diameter, the deeper the penetration depth, if the spot diameter is 200 μm or less, it is possible to secure a penetration depth deeper than 0.1 mm. As an example, it can be joined with a penetration depth of 0.7 mm.

When the spot diameter is reduced to 200 μm or less, deep penetration can be locally ensured, and as a result, thermal influence can be suppressed, thermal strain can be reduced, and the laser in the laser irradiation device 11 can be suppressed. The output of the oscillator can be reduced, and the price of the laser oscillator can be suppressed.

Further, if the laser scanning speed is increased to at least 200 mm / s, the welding time can be shortened as compared with the welding time other than the conventional laser welding, the thermal influence can be suppressed, and the thermal strain can be reduced. be able to.

Further, if the laser output is reduced to 450 W or less, the price of the laser oscillator can be suppressed, and by reducing the heat input, the thermal distortion can be reduced.

When the shaft member 1 is supported by the jig 10, there is a certain dimensional difference (play) between the jig 10 and the shaft member 1 in order to facilitate the attachment of the shaft member 1 to the jig 10. May be set. With this setting, laser welding is performed with the shaft member 1, that is, the pulley 2 rattling with respect to the jig 10 (for example, in a state of being tilted from the vertical direction), and the final product has an annular shape. The joint region 7 is eccentric from the center of the pulley 2 by the amount of play. Here, if the width W1 of the bead 5 is larger than this amount of eccentricity (play), the pulley 2 and the shaft member can be formed by aligning the joint edge 3 with the center of the annular joint region 7 and then starting welding. The joint edge 3 with 1 is surely fitted in the bead 5 having a width W1, and stable bonding can be performed.

That is, assuming that the rattling when the shaft member 1 is supported by the jig 10 is X mm, if the width of the annular joint region 7 is less than X mm, misalignment may occur. Therefore, if the penetration depth is satisfied in the annular joint region 7 having a width of X mm or more, misalignment failure does not occur.

Here, how to obtain the amount of eccentricity (the amount of play) will be described.

Amount of eccentricity = (accuracy of repeating laser irradiation position) + (accuracy of inner diameter of joint edge 3 and outer diameter of shaft member 1) + (accuracy of mounting jig 10 to laser irradiation equipment 19) + (jig 10) One side clearance between and the shaft member 1)
Here, the repeatability of the laser irradiation position means the maximum distance (radiation direction) (μm) at which the spot position shifts due to the shift of the optical system that occurs each time the product is processed. Further, the coaxiality between the inner diameter of the joint edge 3 and the outer diameter of the shaft member 1 means the distance (μm) between the center of the pulley 2 and the center of the shaft member 1 for each product. Further, the one-sided clearance between the jig 10 and the shaft member 1 means the maximum distance (radiation direction) (μm) of the gap generated between the jig 10 and the shaft member 1.

If the amount of eccentricity is obtained by this calculation formula and the penetration depth is satisfied in the annular joint region 7 having a width equal to or larger than this amount of eccentricity, the above-mentioned problem can be prevented from occurring.

In principle, the difference between the adjacent distance on the center side of the shaft member 1 and the adjacent distance on the outer peripheral side of the joint edge 3 should cause a difference in the penetration depth on the inner and outer circumferences. However, as the spot diameter (for example, 50 μm) wraps, laser scanning at narrow intervals when crossing the joint edges 3 can prevent a substantial difference in penetration depth from occurring on the inner and outer circumferences.

That is, in the actual band-shaped bead 5, as an example, in order to cause penetration without a gap on the entire circumference of the joint edge 3, a narrow interval such that the laser spots 9a overlap each other in the meandering back and forth inside and outside the joint edge 3. Laser scanning with. However, even if the laser spots 9a are slightly separated from each other, melting occurs around the spots 9a, so that melting can occur without gaps on the entire circumference of the joint edge 3.

Here, the overlap ratio of the spot diameters of the laser beam 9, that is, the lap ratio = the spot overlap width / the spot diameter on the joint edge 3 is defined. The spot overlap width is set to a positive value when adjacent spots 9a overlap each other, and a negative value when they do not overlap. The spot diameter is, for example, 50 μm.

When the lap ratio was −63% and separated from each other, penetration occurred without gaps on the entire circumference of the joint edge 3 in the circumferential direction, and the entire circumference processing time was about 3 sec. This is the worst example among the examples listed below, and if the minus is larger than this, there is a possibility that a part without penetration may occur repeatedly, which is not preferable.

When the lap ratio is -40% and separated from each other, the variation in the penetration depth in the circumferential direction of the joint edge 3 is 42%, but sufficient strength can be obtained and the full circumference processing time is about 7 sec. It was.

When the lap ratio was -17% and separated from each other, the variation in the penetration depth in the circumferential direction of the joint edge 3 was 36%, but the entire circumference processing time was about 10 sec.

When the lap ratio was 6% and slightly overlapped with each other, the variation in the penetration depth in the circumferential direction of the joint edge 3 was 30%, but the entire circumference processing time was about 15 sec.

When the lap ratio was 22% and overlapped with each other, the variation in the penetration depth in the circumferential direction of the joint edge 3 was 30%, and the entire circumference processing time was about 20 sec.

When the lap ratio was 30% and overlapped with each other, the variation in the penetration depth in the circumferential direction of the joint edge 3 was 10%, but the entire circumference processing time was about 30 sec.

From these examples, the lap ratio is preferably in the range of −40% or more and less than 30%. Within this range, the variation is within 42% to 10%, which not only forms beads without gaps, but also increases the non-defective rate (prevents poor bonding) and shortens the processing time compared to plasma arc welding. it can.

It should be noted that the full-circle processing time by the conventional plasma arc welding requires a time exceeding about 30 sec, but the welding by the laser beam 9 can be shorter than this about 30 sec. Here, the reason why the time can be shortened compared to plasma arc welding is that even if the power of the device is the same, in laser welding, the energy density (J / m ² ) is adjusted extremely high by condensing. On the other hand, in plasma arc welding, the energy density (J / m ² ) is a fixed value and cannot be adjusted high.

As shown in (1) of FIG. 4B, when the heat transfer properties of the two members 12a and 12b with the joint edge 3 as the boundary are equal, the penetration depth 13 of the two members 12a and 12b is (2) of FIG. 4B. It is the same as shown in (4). Note that FIG. 4B (2) shows the joint edge 3 when the laser beam 9 is irradiated at the inner end of the scanning path 8 on the first member 12a side and the intersection interval of the scanning path 8 with respect to the joint edge 3 is wide. Of the two members 12a and 12b in the radial cross section 14 as the boundary, the penetration depth 13 on the first member 12a side near the irradiation position is larger than that of the second member 12b. In FIG. 4B (3), when the laser beam 9 is irradiated at the inner end of the scanning path 8 on the first member 12a side and the intersection interval of the scanning path 8 with respect to the joining edge 3 is narrow, the joining edge 3 is used as a boundary. It shows that the penetration depths 13 of the two members 12a and 12b in the radial cross section 14 are the same. In FIG. 4B (4), when the laser beam 9 is irradiated at the joint edge 3 of the scanning path 8, the penetration depths 13 of the two members 12a and 12b in the radial cross section 15 with the joint edge 3 as a boundary are equal. It represents that.

However. As shown in (1) of FIG. 4C, the heat transfer property differs due to the difference in the carbon content between the two members 12c and 12d, and when the high heat transfer member 12c and the low heat transfer member 12d are adjacent to each other, the penetration occurs. It may become discontinuous at the joint edge 3 which is the boundary between the two members 12c and 12d, and may not reach a predetermined penetration depth on the low heat transfer member 12d side. That is, (2) of FIG. 4C shows high heat transfer among the two members 12c and 12d in the radial cross section 16 with the joint edge 3 as a boundary when the laser beam 9 is irradiated at the joint edge 3 of the scanning path 8. It shows that the penetration depth 13 of the member 12c is larger than that of the low heat transfer member 12d. Assuming that the penetration depth 13 of the high heat transfer member 12c has reached a predetermined penetration depth, the penetration depth 13 of the low heat transfer member 12d has not reached the predetermined penetration depth. In order to avoid such a case, it is necessary to set a larger laser output in accordance with the low heat transfer member 12d in which the penetration depth becomes shallow, and to secure a predetermined penetration depth on the low heat transfer member 12d side. Or performed instead of changing so the setting of the laser power, without setting the laser power changes, the laser welding in a state of setting the laser output to match the high heat transfer member 12c for penetration depth increases However, at the welded portion of the low heat transfer member 12d where the penetration depth is insufficient with the laser output, the scanning time is lengthened or the scanning path 8 is lengthened so as to secure the desired penetration depth. May be good. As an example of lengthening the scan path 8, it is conceivable to overlap the scan paths 8 or add one swirl or circle to lengthen the path.

It is not always necessary that the start point and the end point of the scanning path 8 match, and at a minimum, the path near the start point and the path near the end point need to intersect. For example, even if it is only 5 mm, it may be overlapped. By doing so, the scanning path 8 can be freely set.

According to the above embodiment, as an effect on the conventional laser welding, the laser beam is not irradiated along the edge of the shaft member 101 and the fitting hole 103 of the disk member 102, but intersects with the joint edge 3. Therefore, it is possible to prevent welding defects due to misalignment of circular joints. Further, since the laser beam 9 is locally irradiated to the vicinity of the joint edge 3, the amount of heat input is smaller than that when the conventional welding method such as plasma welding or TIG welding is adopted, and the thermal strain is large. It is possible to significantly suppress the dimensional error before and after the welding process. For this reason, in the past, in TIG welding and the like, a shaving process for removing thermal strain generated in the pulley or a fine adjustment process by a hot press was required after welding, but all of them are no longer necessary, and assembly accuracy and product accuracy are improved. Can be made to. Further, as an effect on plasma welding, since the amount of heat input can be reduced, the processing time can be shortened and the variation in the penetration depth can be reduced. As an example, the welding time in the conventional plasma welding was 40 seconds, but in the above embodiment, it is reduced to 10 seconds, which can be shortened to 1/4, and the conventional plasma welding requires a power of 600 kW. What was there was that the laser output could be reduced to 450 W or less, and the power could be significantly reduced.

The present invention is not limited to the above-described embodiment, and can be implemented in various other aspects as described below. However, in this specification and drawings, the shapes of the scanning paths 8 of various laser beams 9 such as zigzag are clearly described and illustrated for the sake of easy understanding, but in reality, they are the same as those in the previous embodiment. In addition, from the start of formation of the shape of the scanning path 8, it is partially melted by the bonding heat and melts with each other without leaving a clear distinction between the shapes of the scanning path 8 and becomes one thick band-shaped bead 5 as a whole. It has become. However, for the sake of explanation and easy understanding, the shape of the scanning path 8 will be clearly distinguished and described.

(First modification)
As a first modification of the embodiment, as shown in FIG. 5A, when laser welding is performed using the entire circumference of the circular joint edge 3 shown by the dotted line as the scanning path 8, the entire circumference is divided into a plurality of regions and adjacent to each other. It is also possible to suppress the diffusion of the thermal effect by sequentially welding not adjacent regions, for example, every other region. As an example, when the circular joint edge 3 is welded from 0 ° to 360 °, it is divided into 6 parts, then the part 18a from 0 ° to 60 ° is first welded, and then the part from 120 ° to 180 °. 18b, 240 ° to 300 ° part 18c, 60 ° to 120 ° part 18d, 180 ° to 240 ° part 18e, 300 ° to 360 ° part 18f, and so on. May be good.

Further, instead of laser welding the entire circumference, only a part of the entire circumference may be set as the scanning path 8-1 and partially laser welded to further suppress the diffusion of the thermal effect. For example, as shown in FIG. 5B, the circular joint edge 3 is partially formed by a portion 18 g of 0 ° to 5 °, a portion 18h of 120 ° to 125 °, and a portion 18i of 240 ° to 245 °. Welding may be performed in three places by partially weaving. Alternatively, as shown in FIG. 5C, 4 of a portion 18j of 0 ° to 5 °, a portion 18k of 90 ° to 95 °, a portion 18m of 180 ° to 185 °, and a portion 18n of 270 ° to 275 °. Welding may be performed by weaving the portions in the order of diagonally arranged portions such as the portion 18j, the portion 18m, the portion 18k, and the portion 18n. It is preferable that the scanning path 8 intersects the joint edge 3 at least 8 times (for example, when the lap ratio is −40%) in each portion within the angle range of 5 °. As an example, when the lap rate is -17%, it is possible to cross about 10 times.

In the above example, the scanning path 8 is formed along the joint edge 3, but the joint region 7 is rectangular in the tangential direction of the joint edge 3 without following the joint edge 3, for example, as shown in FIG. 5D. It is also possible to set -10 so that the zigzag scanning path 8-10 extends linearly in the scanning path 8-10 so that the scanning path 8-10 overlaps a part of the joint edge 3.

According to this first modification, since welding is performed only on a part of the joint edge 3 instead of the entire circumference, the variation in the penetration depth can be reduced and the thermal strain can be significantly suppressed. ..

(Second modification)
As a second modification, as shown in FIG. 6, the scanning path 8-2 intersects and curves with respect to the circular joint edge 3 so as to meander finely to continuously form a U-shape. It can also be weaved and continuously laser welded. In this way, in the previous embodiment, the scanning speed may decrease due to the zigzag-shaped folding corner, so that the heat input at the portion may increase, but in this second modification, the penetration depth The variation can be made smaller than that of the previous embodiment.

(Third modification example)
As a third modification, as shown in FIG. 7, the scanning path 8-3 intersects and curves with respect to the circular joint edge 3 so as to meander in a large S shape, and weaving in an S shape. Can also be carried out continuously. By doing so, the scanning path 8-3 can be shortened as a whole as compared with the previous embodiment, and the machining time can be shortened.

(Fourth modification)
As a fourth modification, as shown in FIG. 8, the scanning path 8-4 is intermittently intermittently performed by intermittently weaving diagonal lines intersecting the circular joining edge 3 at predetermined intervals. It may be processed as a target. In this way, the scanning path 8-4 is shorter than that of the previous embodiment as a whole, and the machining time can be shortened.

(Fifth modification)
As a fifth modification, as shown in FIG. 9, the scanning paths 8-5 are discontinuously intermittent so as to intermittently perform V-shaped weaving intersecting the circular joining edge 3 at predetermined intervals. It can also be processed as a target. By doing so, the processing time can be shortened as a whole as compared with the previous embodiment.

(6th modification)
As a sixth modification, as shown in FIG. 10, continuous spiral weaving is performed so that the scanning paths 8-6 intersect the circular joint edge 3, and the adjacent vortices are partially separated from each other. It is also possible to perform continuous laser welding so as to overlap each other. By doing so, the scanning paths 8-6 are arranged more finely on the joint edge 3 than in the previous embodiment as a whole, and the variation in the penetration depth is reduced as a whole as compared with the previous embodiment. In addition to being able to reduce the processing time. In this sixth modification, the scanning paths 8-6 are finely arranged on the joint edge 3, and the spots pass through each position of the joint edge 3 a plurality of times in a single time in close proximity to each other. It can be suppressed, and it becomes possible to use the laser irradiation device 11 having a lower power level or the like as compared with the previous embodiment.

(7th modification)
As a seventh modification, as shown in FIG. 11, a large number of circular weaving is carried out so as to intermittently partially overlap the scanning paths 8-7 so as to intersect the circular joint edge 3. , It can also be laser welded intermittently. In this way, the scanning paths 8-7 are arranged more finely on the joint edge 3 than in the previous embodiment as a whole, and the variation in the penetration depth is reduced as a whole as compared with the previous embodiment. Can be done. In this seventh modification, the scanning paths 8-7 are finely arranged on the joint edge 3, and the spots pass through each position of the joint edge 3 a plurality of times in a single time in close proximity to each other. It can be suppressed, and it becomes possible to use the laser irradiation device 11 having a lower power level or the like as compared with the previous embodiment.

(8th modification)
As an eighth modification, as shown in FIG. 12, after the scanning path 8-2 shown in FIG. 6 is set as the scanning path 8-8 of the first round and the junction edge 3 is circled, the phase in the circumferential direction of the junction edge 3 is set. The scanning path 8-2 may be shifted, and then the scanning path 8-2 shown in FIG. 6 may be used as the scanning path 8-9 for the second lap to further circle the junction edge 3 to form the scanning path 8-2 twice. .. In this way, the two-round scanning paths 8-8 and 8-9 are finely arranged on the joint edge 3, and the spots pass through each position of the joint edge 3 multiple times in a single hour. It is possible to suppress the power and the like per rotation, and it is possible to use the laser irradiation device 11 having a lower power and the like as compared with the second modification of FIG. Further, the variation in the penetration depth can be made smaller than that in the second modification of FIG.

In addition, by appropriately combining any embodiment or modification of the various embodiments or modifications, the effects of each can be achieved. Further, it is possible to combine the embodiments or the embodiments, or the embodiments and the embodiments, and also to combine the features in the different embodiments or the embodiments.

The pulley joining method and joining structure according to the present invention can prevent welding defects due to misalignment with respect to circular joining points, and are useful for application to, for example, two-wheeled vehicle parts and the like.

1 Shaft member 2 Pulley 2a Fitting hole 2b Cylindrical part 3 Joint edge 5 Bead 5a Inner thin joint inner edge 5b Outer thin joint outer edge 5c Wide annular joint Main body 5d Groove 5e Raised part 6 Penetration 7 yen Circular junction area 7-10 Rectangular junction region 8,8-1 to 8-10 Scanning path 8a 1st diagonal line 8b 2nd diagonal 8c V-shaped 8d, 8f Intersection 8e, 8g Tangent 8h Inverted V-shaped 9 Laser light 9a Spot 10 Jigger 11 Laser irradiation device 12a First member 12b Second member 12c High heat transfer member 12d Low heat transfer member 13 Penetration depth 14, 15, 16 Radial cross section 18a to 18k, 18m, 18n Joint edge part 19 Laser irradiation equipment

Claims (21)

One of the pulley and the shaft member for torque transmission of the vehicle is a high heat transfer member and the other is a low heat transfer member.
The shaft member is fitted into the fitting hole of the pulley, and the shaft member is fitted.
Then, in the annular joint region including the circular joint edge between the shaft member and the fitting hole, the length of the scanning path in the low heat transfer member is larger than the length of the scanning path in the high heat transfer member. The pulley is formed by irradiating a laser beam along a scanning path that intersects a plurality of times at intervals with respect to the circumferential direction of the joint edge to form a band-shaped bead that overlaps the circular joint edge. A method of joining a pulley for joining and fixing the shaft member and the shaft member. When the shaft member is fitted into the fitting hole, the end portion of the shaft member is placed in the fitting hole of the tubular portion of the pulley, and the peripheral end surface of the fitting hole and the end portion of the shaft member. Fit so that the end faces are flush with each other
When forming the bead, the bead overlaps the circular joint edge formed by the fitting hole of the tubular portion and the end portion of the shaft member, and the end portion of the shaft member. Partially formed in the depth direction,
The method for joining a pulley according to claim 1 . The band-shaped bead has a zigzag shape in which diagonally lined portions intersecting the circular joint edge are connected to each other.
The method for joining a pulley according to claim 1 or 2 . The scanning path has a spiral shape that intersects the circular junction edge.
The method for joining a pulley according to claim 1 or 2 . The scanning path has a curved meandering shape that intersects the circular junction edge.
The method for joining a pulley according to claim 1 or 2 . When irradiating the laser beam, the shaft member is irradiated with the laser beam while being supported by the jig, and the annular joint region with respect to the jig is more eccentric than the center of the pulley. The radial dimension of the strip-shaped bead is large,
The method for joining a pulley according to any one of claims 1 to 5 . When irradiating the laser beam, the laser beam is irradiated in a state where the spot diameter of the laser beam is smaller than the amount of eccentricity.
The method for joining a pulley according to claim 6 . The scanning paths intersect around the circular junction edge.
The method for joining a pulley according to any one of claims 1 to 7 . The scanning paths intersect at a portion of the circular junction edge.
The method for joining a pulley according to any one of claims 1 to 7 . When the scanning path meanders with respect to the junction edge and intersects the junction edge a plurality of times at intervals with respect to the circumferential direction, the spot diameter at which the laser spots of the laser beam overlap on the junction edge. When the overlap ratio of is defined as the lap ratio and the lap ratio is defined as the spot overlap width / spot diameter on the joint edge,
The lap ratio is −40% or more and less than 30%.
The method for joining a pulley according to any one of claims 1 to 9 . One of the pulley and the shaft member for torque transmission of the vehicle is a high heat transfer member and the other is a low heat transfer member.
With the shaft member fitted in the fitting hole of the pulley, the length of the scanning path in the low heat transfer member is longer than the length of the scanning path in the high heat transfer member, and the shaft member and the shaft member The pulley and the shaft member are joined by a laser welded portion of a strip-shaped bead having a laser scanning mark intersecting the circular joint edge with the fitting hole and formed so as to overlap the joint edge. Fixed pulley joint structure. The pulley has a tubular portion having the fitting hole, the shaft member has an end portion to be fitted into the fitting hole, and the fitting hole of the tubular portion is filled with the shaft member. In a state where the end portion is fitted so that the peripheral end surface of the fitting hole and the end surface of the end portion of the shaft member are flush with each other, the fitting hole of the tubular portion and the shaft member The circular joint edge is formed with the end portion, and the bead is partially formed from the end portion of the shaft member in the penetration depth direction from the end portion of the shaft member.
The joint structure of the pulley according to claim 11 . The strip-shaped bead is formed in a zigzag shape in which diagonally lined portions intersecting the circular joint edge are connected to each other and overlap the joint edge.
The joint structure of the pulley according to claim 11 or 12 . The band-shaped bead has a spiral shape that intersects the circular joint edge and is formed so as to overlap the joint edge.
The joint structure of the pulley according to claim 11 or 12 . The band-shaped bead has a curved meandering shape that intersects the circular joint edge and is formed so as to overlap the joint edge.
The joint structure of the pulley according to claim 11 or 12 . The band-shaped beads are formed so as to intersect and overlap the joint edge on the entire circumference of the circular joint edge.
The pulley joining structure according to any one of claims 11 to 15 . The strip-shaped bead is formed so as to intersect and overlap the joint edge at a part of the circular joint edge.
The pulley joining structure according to any one of claims 11 to 15 . The laser scanning marks are formed by alternately arranging grooves and ridges extending in a direction intersecting the joint edge so as to overlap the joint edge.
The joint structure of the pulley according to any one of claims 11 to 17 . The laser welded portion has a heat-transformed portion in each of an adjacent portion on the inner peripheral side of the pulley and an adjacent portion on the outer peripheral side of the pulley with respect to the groove portion and the raised portion.
The joint structure of the pulley according to claim 18 . The laser welded portion is formed approximately along the circular joint edge and around a predetermined central axis, and the central axis is eccentric from the shape center of the pulley, and the width of the band-shaped bead is larger than the amount of eccentricity. Large directional dimensions,
The pulley joining structure according to any one of claims 11 to 19 . The variation of the penetration depth in the circumferential direction in the laser welded portion is 42% to 10%.
Junction structure of the pulley according to any one of claims 11 to 20.