JP6921646B2 - Ultrasonic welding device - Google Patents

Description

The present invention relates to an ultrasonic welding device.

Conventionally, an ultrasonic welding device has been used for welding a sheet member. For example, the welding unit of Patent Document 1 includes an anvil roller and an ultrasonic welding head that cooperates with the anvil roller. The cylindrical contact surface of the anvil roller is provided with a plurality of suction holes and a plurality of protruding teeth. A plurality of suction holes and a plurality of protruding teeth are arranged alternately in each row parallel to the axis.

Japanese Unexamined Patent Publication No. 2016-20275

By the way, as in Patent Document 1, in order to produce an anvil having a plurality of protruding teeth provided on the surface, complicated processing for attaching the plurality of protruding teeth is required. As a result, the manufacturing cost of the ultrasonic welding device increases.

The present invention has been made in view of the above problems, and an object of the present invention is to easily manufacture an anvil and reduce the manufacturing cost of an ultrasonic welding device.

The invention according to claim 1 is an ultrasonic welding apparatus, which has a cylindrical outer peripheral surface centered on a central axis, and an anvil rotating about the central axis and a direction parallel to the central axis. The tip surface extending to the anvil has a head facing the outer peripheral surface of the anvil, and includes an ultrasonic vibrating portion for welding a plurality of sheet members passing between the head and the outer peripheral surface. A plurality of recesses are provided on the outer peripheral surface, and the non-recessed region on the outer peripheral surface is the outermost region separated from the central axis by a certain distance, and the head is interposed via the plurality of sheet members at the time of welding. said to contact the front end surface of the outer peripheral surface of the anvil, the unwelded range plurality of sheet members are not welded, and the welding can weld the range of the plurality of sheet members are provided alternately in the circumferential direction The ratio of the non-recessed region to the region facing the tip surface via the plurality of sheet members at each position on the outer peripheral surface in the circumferential direction is defined as the area ratio of the non-recessed region. The area ratio of the non-concave region in the welding range is lower than the area ratio of the non-recessed region in the non-welding range, and the head passes through the welding range and the non-welding range while maintaining the ON state.

The invention according to claim 2 is the ultrasonic welding apparatus according to claim 1, wherein the non-recessed region is continuous over the entire circumference of the outer peripheral surface.

The invention according to claim 3 is the ultrasonic welding apparatus according to claim 1 or 2, wherein at least a part of the plurality of recesses is a suction hole for holding a sheet member at the time of welding.

The invention according to claim 4 is the ultrasonic welding apparatus according to any one of claims 1 to 3, wherein the area ratio of the non-recessed region on the outer peripheral surface of the anvil is 85% or more. The circumferential range is included in the non-welding range, and the circumferential range in which the area ratio of the non-recessed region is larger than 0% and 35% or less is included in the welding range.

According to the present invention, the manufacturing cost of the ultrasonic welding device can be reduced by making it possible to easily manufacture the anvil.

It is a figure which shows the structure of the ultrasonic welding apparatus. It is a figure which shows the anvil. It is a figure which shows the welding region of a laminated sheet member. It is a figure which shows another example of anvil. It is a figure which shows the anvil seen along the central axis. It is a figure which shows another example of anvil. It is a figure which shows another example of anvil.

FIG. 1 is a diagram showing a configuration of an ultrasonic welding device 1 according to an embodiment of the present invention. The ultrasonic welding device 1 is, for example, a device for ultrasonically welding a plurality of sheet members 9 including a non-woven fabric to each other, and is used for manufacturing an absorbent article.

The ultrasonic welding device 1 includes an anvil (also referred to as an anvil roll) 2, an ultrasonic vibration unit 3, and a plurality of guide rollers 4. The anvil 2 has a cylindrical outer peripheral surface 21 centered on the central axis J1. The anvil 2 is connected to a rotation mechanism 11, and the rotation mechanism 11 rotates the anvil 2 at a constant speed about the central axis J1. In the example of FIG. 1, the anvil 2 rotates clockwise about the central axis J1. The plurality of guide rollers 4 have a rotation axis parallel to the central axis J1 and guide the plurality of seat members 9 which are continuous sheets to the outer peripheral surface 21 of the anvil 2 in a state of being stacked. Each sheet member 9 is a single sheet or a laminated body of a plurality of sheets. Each part of the plurality of sheet members 9 (laminated sheet member 90 described later) that has passed through the anvil 2 is sent to the right side of FIG. On the outer peripheral surface 21 of the anvil 2, a tension of a predetermined magnitude acts on the plurality of sheet members 9. The details of Anvil 2 will be described later.

The ultrasonic vibration unit 3 includes a head 31 and an ultrasonic oscillation unit 32. The ultrasonic wave oscillator 32 generates a voltage having a frequency corresponding to the ultrasonic wave and inputs it to the head 31. The head 31 has a vibrator and a horn. The vibrator converts the voltage from the ultrasonic oscillating unit 32 into longitudinal vibration to generate ultrasonic vibration. The horn is a resonator facing the outer peripheral surface 21 of the anvil 2. The ultrasonic vibration is transmitted to the plurality of seat members 9 on the outer peripheral surface 21 via the horn. In the head 31, a booster may be provided between the vibrator and the horn. In the following description, the surface of the head 31 facing the outer peripheral surface 21 of the anvil 2, that is, the end surface of the horn in contact with the seat member 9, is referred to as "tip surface 311". The tip surface 311 extends in the axial direction parallel to the central axis J1. In the example of FIG. 1, the tip surface 311 is short in the direction perpendicular to the axial direction (tangential direction of the outer peripheral surface 21 of the anvil 2).

FIG. 2 is a diagram showing the anvil 2 and shows the outer peripheral surface 21 seen from the direction perpendicular to the central axis J1. In FIG. 2, the axial range in which the seat member 9 exists is indicated by an arrow with the same reference numeral 9. The head 31 described above is also shown in the figure. On the outer peripheral surface 21 of the anvil 2, the axial range that does not face the tip surface 311 of the head 31 (does not overlap in the normal direction) does not affect the welding of the seat member 9, and faces the tip surface 311 in the axial direction. The range of (hereinafter referred to as "effective range") is effective for welding. In the following description, the term "outer peripheral surface 21" means the region of the outer peripheral surface 21 included in the effective range.

The anvil 2 includes a plurality of circular recesses 22, and the plurality of recesses 22 are formed on the outer peripheral surface 21. In the example of FIG. 2, two or more recesses 22 arranged at regular intervals in the axial direction are defined as recess rows 23, and a plurality of recess rows 23 are arranged over the entire circumference along the circumferential direction centered on the central axis J1. .. In the anvil 2, the arrangement pattern of the plurality of recesses 22 may be appropriately changed. For example, the positions of the plurality of recess rows 23 in the axial direction may fluctuate along the circumferential direction. An example of this case is a pattern in which a plurality of recesses 22 are arranged in a staggered pattern.

The outer peripheral surface 21 of the anvil 2 is a cylindrical surface separated from the central axis J1 by a certain distance, and the plurality of recesses 22 are formed by, for example, hole processing or grooving (including deburring processing) on the outer peripheral surface 21. NS. Some of the recesses 22 of the plurality of recesses 22 are connected to the decompression mechanism via the internal space of the anvil 2. The recess 22 connected to the decompression mechanism serves as a suction hole for holding the sheet member 9 during welding. In the anvil 2, all the recesses 22 may be connected to the decompression mechanism. That is, at least a part of the plurality of recesses 22 is formed as suction holes.

When the region of the outer peripheral surface 21 excluding the plurality of recesses 22 is referred to as a non-recessed region 24, the non-recessed region 24 is the outermost region of the outer peripheral surface 21 farthest from the central axis J1. To be precise, the non-recessed region 24 may be the outermost region in the effective range of the outer peripheral surface 21. In the non-recessed region 24, the distance from the central axis J1 is the same at any position. Since the plurality of recesses 22 are provided discretely (isolated from each other), the non-recessed region 24 is continuous over the entire circumference of the outer peripheral surface 21.

In the ultrasonic welding device 1 of FIG. 1, a plurality of guide rollers 4 guide the plurality of sheet members 9 to the outer peripheral surface 21 of the anvil 2 in a state of being overlapped with each other. The plurality of sheet members 9 pass between the head 31 and the outer peripheral surface 21 in a state of being held on the outer peripheral surface 21 by the recesses 22 (suction holes) connected to the decompression mechanism. That is, between the head 31 and the anvil 2, the plurality of seat members 9 move in the same direction as the outer peripheral surface 21 at the same speed. The ultrasonic vibration is continuously generated by the continuous drive of the ultrasonic vibration unit 3, and the ultrasonic vibration is applied to each part of the plurality of sheet members 9 facing the tip surface 311 of the head 31. .. As a result, in the portion of the plurality of sheet members 9, the region facing the non-recessed region 24, which is the outermost region of the anvil 2, is welded (joined) by ultrasonic vibration. In the following description, a plurality of sheet members 9 joined to each other by welding are referred to as "laminated sheet members". In FIG. 1, reference numerals 90 are attached to the laminated sheet members.

FIG. 3 is a diagram showing a welding region 91 of the laminated sheet member 90. The welding region 91 is a region where a plurality of sheet members 9 are welded to each other, and in FIG. 3, the welding region 91 is shaded in parallel. The pattern shown by the plurality of welding regions 91 is also called a welding pattern. In the laminated sheet member 90, a region substantially overlapping the non-recessed region 24 is a welding region 91. As described above, since the ultrasonic vibration unit 3 is continuously driven, the laminated sheet member 90 is continuously formed with a welding pattern in the longitudinal direction. For example, in the production of an absorbent article such as a disposable diaper, the welding pattern of FIG. The laminated sheet member 90 is manufactured using the anvil 2) of FIG.

In the example of FIG. 2, a gap is provided between the recess rows 23 adjacent to each other in the circumferential direction. That is, the non-recessed region 24 includes a linear region extending in the axial direction over the entire effective range of the outer peripheral surface 21. In FIG. 2, one linear region is shown by a rectangle of the alternate long and short dash line with the symbol L1. In the ultrasonic welding device 1, when the tip surface 311 of the head 31 faces the linear region L1, most of the tip surface 311 comes into contact with the non-recessed region 24 via the plurality of sheet members 9. In this case, since the vibration energy is dispersed, welding of the plurality of sheet members 9 hardly occurs. As a result, in the welding pattern shown in FIG. 3, a non-welding region corresponding to the linear region L1 exists between the welding regions 91 adjacent to each other in the vertical direction of FIG. 3 corresponding to the longitudinal direction of the sheet member 9. do.

Here, at each position in the circumferential direction on the outer peripheral surface 21 of the anvil 2, the ratio of the non-recessed region 24 to the region facing the tip surface 311 of the head 31 via the plurality of seat members 9 is "non-recessed region". It is called "24 area ratio". The area ratio of the non-recessed region 24 can also be regarded as the area ratio of the outermost region of the outer peripheral surface 21. In an example of the ultrasonic welding device 1, when the area ratio of the non-recessed region 24 is 85% or more, welding of a plurality of sheet members 9 is impossible. Further, when the area ratio of the non-recessed region 24 is larger than 0% and 35% or less, welding of a plurality of sheet members 9 is possible. Actually, whether or not the plurality of sheet members 9 can be welded depends on the magnitude and frequency of the voltage applied to the head 31 by the ultrasonic oscillator 32, so that the lower limit of the area ratio at which welding is impossible and the lower limit of the area ratio, and The upper limit of the area ratio at which welding is possible varies depending on the input voltage to the head 31 and the like. Therefore, in one example of the ultrasonic welding device 1, when the area ratio of the non-recessed region 24 is within a range larger than 35% and smaller than 85%, whether or not welding is possible depends on the input voltage and the like.

For example, when the input voltage is relatively large, when the area ratio of the non-recessed region 24 is 60% or less, welding of a plurality of sheet members 9 is possible, and the area ratio of the non-recessed region 24 is 85%. When this is the case, welding of the plurality of sheet members 9 is impossible. When the input voltage is relatively small, when the area ratio of the non-recessed region 24 is 35% or less, welding of a plurality of sheet members 9 is possible, and the area ratio of the non-recessed region 24 is 60% or more. At some point, welding of the plurality of sheet members 9 is impossible.

Here, as in JP-A-2016-120275 (Patent Document 1), an anvil of a comparative example in which a plurality of protruding teeth and a plurality of suction holes are provided on the outer peripheral surface is assumed. In the anvil of the comparative example, protruding teeth and suction holes are alternately arranged in each row parallel to the central axis. In order to produce the anvil of the comparative example, complicated processing for attaching a plurality of protruding teeth to the outer peripheral surface is required. As a result, the manufacturing cost of the ultrasonic welding device using the anvil of the comparative example increases. In addition, since the heights of multiple protruding teeth (distance between the top of the protruding teeth and the central axis of the anvil) vary, the head of the ultrasonic vibrating part can be positioned appropriately with respect to the anvil (stable welding is possible). The adjustment work of arranging at the position) becomes extremely complicated.

On the other hand, in the anvil 2 of the ultrasonic welding device 1, a plurality of recesses 22 are provided on the outer peripheral surface 21, and the non-recessed region 24 on the outer peripheral surface 21 is the outermost region separated from the central axis J1 by a certain distance. .. Then, the non-recessed region 24 comes into contact with the tip surface 311 of the head 31 via a plurality of sheet members 9 during welding. Since the anvil 2 having the above structure can be easily manufactured by drilling or grooving the cylindrical member, the manufacturing cost of the ultrasonic welding device 1 can be reduced. Further, since the distance between the non-recessed region 24, which is the outermost region of the anvil 2, and the central axis J1 is constant over the entire circumference, it is easy to adjust the position of the head 31 with respect to the anvil 2. It can be carried out. Further, since at least a part of the plurality of recesses 22 is suction holes connected to the decompression mechanism, it is possible to suppress loosening of the sheet member 9 at the time of welding.

Further, in the anvil of the comparative example, the distance between the edge of the suction hole and the central axis is smaller than the distance between the apex of the protruding tooth and the central axis. That is, when the sheet member is welded, a height difference is generated between the top portion in contact with the head via the sheet member and the edge portion of the suction hole. As a result, for example, welding may be performed in a state where the sheet member is loosened according to the height difference, and wrinkles may occur in the laminated sheet member. On the other hand, in the anvil 2 of FIG. 2, the edge portion of the recess 22 which is the suction hole is included in the outermost region of the outer peripheral surface 21. Thereby, it is possible to suppress or prevent the occurrence of wrinkles on the laminated sheet member.

In the ultrasonic welding device 1 of FIG. 1, a welding pattern is continuously formed on the laminated sheet member 90 in the longitudinal direction, but a welding pattern may be formed intermittently in the longitudinal direction. FIG. 4 is a diagram showing another example of the anvil 2. Similar to the anvil 2 in FIG. 2, the outer peripheral surface 21 of the anvil 2 in FIG. 4 is a cylindrical surface separated from the central axis J1 by a certain distance, and a plurality of rectangular recesses 22 are formed by making holes in the outer peripheral surface 21. Is formed by. A part or all of the plurality of recesses 22 are suction holes connected to the decompression mechanism. The non-recessed region 24 on the outer peripheral surface 21 is the outermost region farthest from the central axis J1. The non-recessed region 24 is continuous over the entire circumference of the outer peripheral surface 21.

A set of a plurality of recessed rows 23 (two in FIG. 4) adjacent to each other in the circumferential direction is designated as a recessed row group 230, and a plurality of recessed row groups 230 are provided on the outer peripheral surface 21 at equal angular intervals in the circumferential direction. .. The plurality of recess row groups 230 are arranged at intervals of 90 degrees, for example (see FIG. 5 described later). Typically, the width of the space between the two recessed rows 230 in the circumferential direction is sufficiently larger than the circumferential length of each recess 22. Further, the gap between the recess rows 23 adjacent to each other in each recess row group 230 is smaller than the circumferential length of each recess 22. The recess row group 230 may be one recess row 23.

In the space between the recessed row groups 230, the area ratio of the non-recessed region 24 becomes high, so that welding of the plurality of sheet members 9 becomes impossible. On the other hand, in the region where the recess row group 230 is provided (excluding the gap between the recess rows 23 adjacent to each other), the area ratio of the non-recess region 24 is low, so that a plurality of sheet members 9 can be welded. As described above, in the anvil 2, the non-welding range A1 in which the plurality of sheet members 9 are not welded on the outer peripheral surface 21 and the welding range A2 in which the plurality of sheet members 9 can be welded are alternately provided in the circumferential direction.

FIG. 5 is a diagram showing an anvil 2 viewed along the central axis J1. In FIGS. 4 and 5, the non-welding range A1 is indicated by an arrow with reference numeral A1, and the welding range A2 is indicated by an arrow with reference numeral A2. Strictly speaking, in the gaps between the recessed rows 23 adjacent to each other in each recessed row group 230, the area ratio of the non-recessed region 24 becomes high, so that welding of the plurality of sheet members 9 becomes impossible. Since the width of the gap is small, the gap is also included in the welding range A2 here. In the anvil 2, with the exception of the gap in the welding range A2, the area ratio of the non-recessed region 24 in the welding range A2 is lower than the area ratio of the non-recessed region 24 in the non-welding range A1.

In the above-described example, when the area ratio of the non-recessed region 24 is 85% or more, welding of the plurality of sheet members 9 is impossible, the area ratio of the non-recessed region 24 is larger than 0%, and 35. When it is less than%, welding of a plurality of sheet members 9 is possible. In this case, on the outer peripheral surface 21 of the anvil 2, the circumferential range in which the area ratio of the non-recessed region 24 is 85% or more is included in the non-welding range A1, and the area ratio of the non-recessed region 24 is larger than 0%. Moreover, it can be said that the circumferential range of 35% or less is included in the welding range A2.

In the ultrasonic welding device 1, the anvil 2 rotates while continuously driving the ultrasonic vibrating unit 3. In other words, the head 31 alternately passes through the welding range A2 and the non-welding range A1 on the outer peripheral surface 21 of the anvil 2 while maintaining the ON state. At this time, a plurality of sheet members 9 stacked on each other pass between the head 31 and the outer peripheral surface 21. As a result, a welding pattern is intermittently formed in the longitudinal direction with respect to the laminated sheet member 90. For example, in the manufacture of pants-type disposable diapers, in the intermittent joining (side seal) between a seat member having a continuous portion corresponding to the front portion of the disposable diaper and a seat member having a continuous portion corresponding to the rear portion of the disposable diaper. , The laminated sheet member 90 is formed using the anvil 2 of FIG.

By the way, in the anvil of the above comparative example in which a plurality of protruding teeth (and a plurality of suction holes) are formed, when the region where the protruding teeth are provided and the region where the protruding teeth are not provided are alternately set in the circumferential direction, In the area where the protruding teeth are not provided, the head is separated from the anvil. At this time, if the head is maintained in the ON state, the head may be damaged, so that the head is kept in the OFF state while facing the region. However, in the head, after switching from the OFF state to the ON state, it takes a certain amount of time until welding becomes stable and possible. Therefore, when the head is switched from the OFF state to the ON state when the region where the protruding teeth are provided and the head face each other, the welding strength may be weakened at the portion of the sheet member to be welded immediately after the switching.

On the other hand, in the ultrasonic welding device 1 including the anvil 2 in FIG. 4, the non-welded range A1 in which the area ratio of the non-recessed region 24, which is the outermost region, is relatively high on the outer peripheral surface 21 of the anvil 2 and the non-welding range A1. Welding ranges A2, which have a relatively low area ratio of the recessed regions 24, are alternately provided in the circumferential direction. Then, the head 31 passes through the welding range A2 and the non-welding range A1 while maintaining the ON state. As a result, the head 31 is always in contact with the anvil 2 with the seat member 9 sandwiched between them to prevent damage to the head 31, and a plurality of seat members 9 can be stably welded in the welding range A2. It will be realized. Further, since at least a part of the recess 22 provided in the welding range A2 is a suction hole for holding the sheet member 9 at the time of welding, it is possible to suppress the loosening of the sheet member 9 at the time of welding. Further, similarly to the anvil 2 in FIG. 2, a plurality of recesses 22 are provided on the outer peripheral surface 21, and the non-recessed region 24 becomes the outermost region separated from the central axis J1 by a certain distance. As a result, the anvil 2 can be easily manufactured and the manufacturing cost of the ultrasonic welding device 1 can be reduced. Further, the work of adjusting the position of the head 31 with respect to the anvil 2 can be easily performed.

FIG. 6 is a diagram showing another example of the anvil 2. In the anvil 2 of FIG. 6, similarly to the anvil 2 of FIG. 4, the non-welding range A1 in which the plurality of sheet members 9 are not welded on the outer peripheral surface 21 and the welding range A2 in which the plurality of sheet members 9 can be welded are provided. It is provided alternately in the circumferential direction. In the welding range A2, two or more recesses 22 arranged at regular intervals in the axial direction are provided as recess rows 23. In the example of FIG. 6, one recess row 23 is the recess row group 230. Further, auxiliary recesses 22a extending in the axial direction are formed on both sides of the recess row 23 in the circumferential direction. In FIG. 6, the outer shape of each auxiliary recess 22a is shown by a two-dot chain line. Each auxiliary recess 22a is continuous with all the recesses 22 in the recess row 23 without sandwiching the non-recessed region 24. In other words, in the portion of the non-recessed region 24 existing between the two recesses 22 adjacent to each other in the recess row 23, the periphery thereof is surrounded by the two recesses 22 and the two auxiliary recesses 22a, and the portion is not. It is isolated from other parts of the recessed region 24. The portion can be regarded as a convex portion 25.

In the welding range A2, the area ratio of the non-recessed region 24 is relatively small except for the position of the auxiliary recess 22a. At the position of the auxiliary recess 22a, the area ratio of the non-recessed region 24 becomes 0, and the plurality of sheet members 9 are not welded. 22a is also included in the welding range A2. Since the width of the auxiliary recess 22a in the circumferential direction is small and the head 31 is in contact with the plurality of seat members 9 in a tense state due to tension, the head 31 is not damaged when passing through the auxiliary recess 22a. ..

In the non-welding range A1, several recesses 22b are provided. These recesses 22b are suction holes connected to the decompression mechanism. In the example of FIG. 6, the four recesses 22b are arranged in the axial direction with a sufficient gap. The area ratio of the non-recessed region 24 in the non-welded range A1 is sufficiently higher than the area ratio of the non-recessed region 24 in the welding range A2, and in the non-welded range A1, welding of a plurality of sheet members 9 becomes impossible.

Also in the ultrasonic welding device 1 including the anvil 2 of FIG. 6, the head 31 passes through the non-welding range A1 and the welding range A2 including the outermost region while maintaining the ON state. As a result, welding of the plurality of sheet members 9 can be stably performed. Further, in the welding range A2, a part (convex portion 25) of the non-recessed region 24 which is the outermost region is surrounded by the recesses 22 and 22a. As a result, in the laminated sheet member 90, a clear pattern of the welded region corresponding to the surface shape of the convex portion 25 (the shape of the surface included in the outermost region) can be formed. Further, the non-recessed region 24 on the outer peripheral surface 21 excluding the recesses 22, 22a and 22b is the outermost region separated from the central axis J1 by a certain distance. As a result, the anvil 2 can be easily manufactured and the manufacturing cost of the ultrasonic welding device 1 can be reduced. Further, the work of adjusting the position of the head 31 with respect to the anvil 2 can be easily performed.

In the anvil 2, the seat member 9 can be appropriately held by suction of the seat member 9 by the recess 22b provided in the non-welding range A1. Further, since the edge portion of the recess 22b is included in the outermost region of the outer peripheral surface 21, it is possible to suppress or prevent wrinkles from being generated in the laminated sheet member 90. The width of the seat member 9 may be made larger than the length of the auxiliary recess 22a in the axial direction. In this case, since both edges of the sheet member 9 along the longitudinal direction are in contact with both outer portions of the auxiliary recess 22a in the axial direction on the outer peripheral surface 21, the vicinity of both edges of the sheet member 9 is brought into contact with each other during welding. Loosening is suppressed.

The recess 22b, which is a suction hole, can also be provided in the welding range A2. In FIG. 7, the recess 22b is provided in the convex portion 25 existing between the two recesses 22 adjacent to each other in the recess row 23. Also in this case, the edge portion of the recess 22b is included in the outermost region of the outer peripheral surface 21. In the anvil 2 of FIG. 7, the recess 22b provided in the welding range A2 holds the sheet member 9 during welding. As described above, since the suction holes are present in the welding range A2, it is possible to suppress the loosening of the sheet member 9 at the time of welding.

The ultrasonic welding device 1 can be deformed in various ways.

The shape of the recess 22 in the anvil 2 may be changed as appropriate. As described above, since the shape of the welding region in the laminated sheet member 90 depends on the shape of the recess 22, it is possible to realize various shapes of the welding region by changing the shape of the recess 22. Of course, the number, size, and arrangement of the recesses 22 may be changed in various ways. Further, in the anvil 2, the suction hole may be omitted, and the seat member 9 may be held on the outer peripheral surface of the anvil 2 by using only the tension acting on the seat member 9.

On the outer peripheral surface 21 of the anvil 2, only one non-welding range A1 and one welding range A2 may be provided. In this case as well, it can be considered that the non-welding range A1 and the welding range A2 are alternately provided in the circumferential direction on the outer peripheral surface 21.

When the decrease in welding strength in the laminated sheet member 90 is within the permissible range, even if a welding pattern is intermittently formed in the longitudinal direction in the laminated sheet member 90 by switching ON / OFF of the head 31. good.

In the above embodiment, two sheet members 9 are welded, but three or more sheet members 9 may be welded to each other.

The ultrasonic welding device 1 may be used for purposes other than manufacturing an absorbent article. Further, the sheet member 9 may be formed of a sheet other than the non-woven fabric.

The above-described embodiment and the configurations in each modification may be appropriately combined as long as they do not conflict with each other.

1 Ultrasonic welding device 2 Anvil 3 Ultrasonic vibrating part 9 Seat member 21 Outer peripheral surface 22, 22a, 22b Recessed 24 Non-recessed area 31 Head 311 Tip surface A1 Non-welding range A2 Welding range J1 Central axis

Claims (4)

It is an ultrasonic welding device,
An anvil that has a cylindrical outer peripheral surface centered on the central axis and rotates around the central axis.
An ultrasonic vibrating unit having a head whose tip surface extending in a direction parallel to the central axis faces the outer peripheral surface of the anvil and welding a plurality of sheet members passing between the head and the outer peripheral surface. ,
With
A plurality of recesses are provided on the outer peripheral surface of the anvil.
Non-recessed region of the outer circumferential surface, a outermost regions spaced by a predetermined distance from said central axis, via a plurality of sheet members during the welding and contact with the front end surface of the head,
On the outer peripheral surface of the anvil, a non-welding range in which the plurality of sheet members are not welded and a welding range in which the plurality of sheet members can be welded are alternately provided in the circumferential direction.
The welding range is defined as the ratio of the non-recessed region to the region facing the tip surface via the plurality of sheet members at each position on the outer peripheral surface in the circumferential direction as the area ratio of the non-recessed region. The area ratio of the non-recessed region in the above is lower than the area ratio of the non-recessed region in the non-welded range.
An ultrasonic welding device characterized in that the head passes through the welding range and the non-welding range while maintaining an ON state. The ultrasonic welding apparatus according to claim 1.
An ultrasonic welding device characterized in that the non-recessed region is continuous over the entire circumference of the outer peripheral surface. The ultrasonic welding apparatus according to claim 1 or 2.
An ultrasonic welding device, wherein at least a part of the plurality of recesses is a suction hole for holding a sheet member during welding. The ultrasonic welding apparatus according to any one of claims 1 to 3.
On the outer peripheral surface of the anvil, the circumferential range in which the area ratio of the non-recessed region is 85% or more is included in the non-welding range, the area ratio of the non-recessed region is larger than 0%, and the area ratio is larger than 0%. , 35% or less of the circumferential direction is included in the welding range.

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