Ultrasonic dissolution device

Abstract

To facilitate welding in a wide range of areas.SOLUTION: An ultrasonic welding device 1 has an anvil 2 and an ultrasonic vibration unit 3 with a head 31. The anvil 2 has a cylindrical outer circumferential surface 21 having a central axis J1. The outer circumferential surface 21 of the anvil 2 has a welding surface for welding a plurality of sheet members 9 between it and the opposing head 31, and the minimum width of the welding surface is 5 mm or more. The welding surface with a minimum width of 5 mm or greater has a recess with a maximum width of 1 mm or less. In one example of the recesses, the recesses are a set of uniformly dispersed granular micro-recesses.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an ultrasonic welding apparatus for welding a plurality of sheet members using ultrasonic waves.

Background Art

[0002] Conventionally, a technique of welding a plurality of stacked sheet members by sandwiching them between an ultrasonic vibrating head and a substantially cylindrical anvil has been used in various fields. For example, in the production of disposable absorbent articles and disposable masks, ultrasonic welding is used when joining a plurality of non-woven fabric sheets. In Patent Document 1, a suction hole is provided at the tip of a protrusion provided on the outer peripheral surface of the anvil. Thereby, it is possible to suppress the sheet member from bending in the axial direction during welding.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in joining using ultrasonic welding, joining has conventionally been performed in a minute region. This is because when attempting to join in a large region, holes are likely to occur at the joining portion. That is, when joining sheet members by welding over a wide range, it becomes difficult to join uniformly due to reasons such as heat accumulation in the sheet members.

[0005] The present invention has been made in view of the above problems, and an object thereof is to easily perform welding over a wide range.

Means for Solving the Problems

[0006] One aspect of the present invention is an ultrasonic welding apparatus comprising: an anvil having a cylindrical outer surface about a central axis and rotating about the central axis; and an ultrasonic vibrating unit having a head facing the outer surface of the anvil and welding a plurality of sheet members passing between the head and the outer surface, wherein the outer surface of the anvil has a welding surface for welding the plurality of sheet members with the head, the minimum width of the welding surface is 5 mm or more, and the maximum width of the welding surface is It is a collection of granular micro-recesses smaller than 0.1 mm. It has a recess. Aspect 2 of the present invention is an ultrasonic welding apparatus comprising an anvil having a cylindrical outer surface centered on a central axis and rotating about the central axis, and an ultrasonic vibrating unit having a head facing the outer surface of the anvil and welding a plurality of sheet members passing between the head and the outer surface, wherein the outer surface of the anvil has a welding surface for welding the plurality of sheet members with the head, the minimum width of the welding surface is 5 mm or more, and the welding surface has a recess which is a collection of groove-shaped recesses with a maximum width of 0.1 mm or less.

[0007] Embodiments of the present invention 3 This is aspect 1 or 2 An ultrasonic welding apparatus wherein, when the welding surface is viewed from a direction opposite to the outer peripheral surface of the anvil, the welding surface is present around the entire circumference of the recess.

[0008] Embodiments of the present invention 4 This refers to aspect 1 or 2 (Any one of the embodiments 1 to 3 may be used.) An ultrasonic welding apparatus wherein the welding surface is the tip surface of a projection on the outer circumferential surface of the anvil, the outer circumferential surface of the anvil includes other projections that are the same height as the projection and have a maximum width of 2 mm or less, and the projection and the other projections are aligned in a direction parallel to the central axis.

[0009] Embodiments of the present invention 5 This refers to the aspect 1 or 2 (aspect 1 to 4 It may be any one of the following: an ultrasonic welding apparatus in which, when viewed macroscopically, the recesses are uniformly distributed on the welding surface, and the length between recesses on a straight line parallel to the central axis, excluding the outer edge of the welding surface, is 5 times or more and 500 times or less the length of the recesses on that straight line.

[0011] Aspect 6 of the present invention is an ultrasonic welding apparatus according to aspect 1 or 2 (or any one of aspects 1 to 5), wherein the depth of the recess is 0.05 mm or more. [Effects of the Invention]

[0012] According to the present invention, welding can be easily performed over a wide range.

Brief Description of the Drawings

[0013] [Figure 1] It is a diagram showing the configuration of an ultrasonic welding apparatus. [Figure 2] It is a diagram showing the configuration of the head. [Figure 3] It is a diagram showing the outer peripheral surface of the anvil developed. [Figure 4] It is a diagram showing the laminated sheet member after joining. [Figure 5] It is a diagram showing a wide welding surface and a part of it enlarged and shown downward. [Figure 6] It is a diagram showing a further enlarged part of the wide welding surface. [Figure 7] It is a diagram showing another example of the wide welding surface. [Figure 8] It is a diagram showing still another example of the wide welding surface. [Figure 9] It is a diagram showing still another example of the wide welding surface.

Embodiments for Carrying Out the Invention

[0014] FIG. 1 is a diagram showing the configuration of an ultrasonic welding apparatus 1 according to an embodiment of the present invention. The ultrasonic welding apparatus 1 is, for example, an apparatus for ultrasonic welding a plurality of sheet members 9 including non-woven fabric, and is used in the manufacture of disposable absorbent articles, disposable masks, and the like.

[0015] The ultrasonic welding apparatus 1 comprises an anvil (also called an anvil roll) 2, an ultrasonic vibration unit 3, and a plurality of guide rollers 4. The anvil 2 has a cylindrical outer surface 21 centered on a central axis J1. The anvil 2 is connected to a rotation mechanism 11, which rotates the anvil 2 at a constant speed around the central axis J1. In the example shown in Figure 1, the anvil 2 rotates clockwise around the central axis J1. The plurality of guide rollers 4 have rotation axes parallel to the central axis J1 and guide a plurality of sheet members 9, which are continuous sheets, stacked on top of each other, to the outer surface 21 of the anvil 2. Each sheet member 9 is either a single sheet or a laminate of multiple sheets. Each part of the laminated sheet members 9 (hereinafter referred to as "laminated sheet members 90") that has passed through the anvil 2 after joining is sent to the right side of Figure 1. On the outer surface 21 of the anvil 2, a predetermined tension acts on each sheet member 9 in its longitudinal direction.

[0016] The ultrasonic vibration unit 3 comprises a head 31 and an ultrasonic oscillator 32. The ultrasonic oscillator 32 generates a voltage with a frequency corresponding to ultrasound and inputs it to the head 31. The ultrasonic vibration unit 3 welds multiple sheet members 9 that pass between the head 31 and the outer circumferential surface 21. Figure 2 shows the configuration of the head 31. The head 31 faces the outer circumferential surface 21 of the anvil 2. The direction perpendicular to the plane of the paper in Figure 2 corresponds to the left-right direction in Figure 1. The head 31 has a transducer 311, a booster 312, and a horn 313. The transducer 311 converts the voltage from the ultrasonic oscillator 32 into vertical vibrations in the up-down direction of Figure 2 to generate ultrasonic vibrations. The ultrasonic vibrations are transmitted to the horn 313 via the booster 312 at a desired amplitude. The horn 313 is a resonator facing the outer circumferential surface 21 of the anvil 2. The magnitude of the force that sandwiches the sheet members 9 between the horn 313 and the outer circumferential surface 21 can be controlled by settings, etc.

[0017] The ultrasonic vibration is transmitted to the plurality of sheet members 9 on the outer peripheral surface 21 via the horn 313. The plurality of sheet members 9 are sandwiched so as to contact between the horn 313 and the outer peripheral surface 21 of the anvil 2. In FIG. 2, however, the horn 313, the plurality of sheet members 9 and the outer peripheral surface 21 of the anvil 2 are shown spaced apart. The booster 312 may be omitted or may be replaced with other components. The surface of the horn 313 facing the outer peripheral surface 21, that is, the end face of the horn 313 contacting the sheet member 9 is elongated in the axial direction parallel to the central axis J1 (see FIG. 1) and short in the direction perpendicular to the axial direction (the tangential direction of the outer peripheral surface 21 of the anvil 2).

[0018] FIG. 3 is a view showing the outer peripheral surface 21 of the anvil 2 developed, where the left-right direction is the direction parallel to the central axis J1 and the up-down direction corresponds to the circumferential direction. Since FIG. 3 is a developed view, it is also a view of the outer peripheral surface 21 seen from the direction facing the outer peripheral surface 21. That is, FIG. 3 is a view of the outer peripheral surface 21 seen from the radially outward direction of the anvil 2 toward the central axis J1. In FIG. 3, the end face of the horn 313 facing the outer peripheral surface 21 is shown by a two-dot chain line. FIG. 4 is a view showing the laminated sheet member 90 after joining. In FIG. 3, the end face of the horn 313 moves relatively from the upper side to the lower side of the figure. FIG. 4 shows the state of the joined region seen from the anvil 2 side, that is, the state seen from below in FIG. 1. The right side of FIG. 3 corresponds to the left side of FIG. 4, and the up-down direction of FIG. 3 corresponds to the up-down direction of FIG. 4. In FIG. 4, the laminated sheet member 90 is conveyed from bottom to top.

[0019] In the example shown in Figure 3, the outer circumferential surface 21 of the anvil 2 has one wide projection 22 and a number of narrow projections 23. The narrow projections 23 are arranged in two rows in the circumferential direction. The height of the wide projection 22 and the height of the narrow projections 23 are the same. In other words, the distance from the central axis J1 to the tip surface of the wide projection 22 is the same as the distance from the central axis J1 to the tip surface of the narrow projection 23. This makes it easy to form the wide projection 22 and the narrow projections 23 when manufacturing the anvil 2. The tip surfaces of the wide projection 22 and the tip surfaces of the narrow projections 23 are welding surfaces that weld multiple sheet members 9 together with the head 31. Hereinafter, the tip surface of the wide projection 22 will be referred to as the "wide welding surface 221," and the tip surface of the narrow projection 23 will be referred to as the "narrow welding surface 231."

[0020] The minimum width of the wide welding surface 221 is 5 mm or more. Here, "minimum width" refers to the minimum width when the object is sandwiched between two parallel lines from various directions in the unfolded diagram of Figure 3. For example, if the welding surface is circular in the unfolded diagram, the minimum width is its diameter. If the welding surface is rectangular in the unfolded diagram, the minimum width is the length of its shorter side. The maximum width of the narrow welding surface 231 is 2 mm or less. Here, "maximum width" refers to the maximum width when the object is sandwiched between two parallel lines from various directions in the unfolded diagram of Figure 3. For example, if the welding surface is circular in the unfolded diagram, the maximum width is its diameter. If the welding surface is rectangular in the unfolded diagram, the maximum width is the length of its diagonal.

[0021] By welding multiple sheet members 9 using the anvil 2 having the outer peripheral surface 21 shown in Figure 3, a laminated sheet member 90 is obtained having numerous narrow welded regions 931 and wide welded regions 921 that are spaced apart, as shown in Figure 4. Multiple sheet members 9 are welded in the wide welded regions 921 and the narrow welded regions 931. The wide welded regions 921 are the traces of welding performed between the wide projection 22 and the head 31. The narrow welded regions 931 are the traces of welding performed between the narrow projection 23 and the head 31. In Figure 4, dashed lines are shown for each full circumference of the anvil 2.

[0022] Figure 5 shows the wide welding surface 221 of the wide projection 22, and a magnified view of a part thereof (labeled 22a) below. In Figure 5, the horizontal direction (left-right direction) is parallel to the central axis J1, and the vertical direction (up-down direction) is the circumferential direction of the outer surface 21. As shown in the magnified view, countless minute recesses 222 are formed on the wide welding surface 221. In the example of Figure 5, the outer shape of each minute recess 222 is circular, and the minute recess 222 is a roughly cylindrical space. The shape of the bottom of the minute recess 222 may be flat, spherical, or conical. The maximum width of each minute recess 222 is 1 mm or less. The "maximum width" here is the same as the definition of the maximum width of the narrow welding surface 231. In Figure 5, only two dashed lines connecting the centers of the minute recesses 222 arranged horizontally are drawn, and these dashed lines are labeled 223. Hereafter, a row of minute recesses 222 arranged horizontally will be referred to as "row 223". Additionally, only two dashed lines are drawn connecting the centers of minute recesses 222 arranged vertically, and these dashed lines are labeled with the symbol 224. Hereafter, a row of minute recesses 222 arranged vertically will be referred to as "row 224". Rows 223, in which minute recesses 222 are arranged horizontally, and rows 224, in which minute recesses 222 are arranged vertically, exist in large numbers at equal intervals.

[0023] As will be described later, the wide welding surface 221 may have recesses in various forms. In the example in Figure 5, the recesses provided on the wide welding surface 221 are a collection of uniformly dispersed granular micro-recesses 222. Hereinafter, the entire set of recesses provided on the wide welding surface 221 will be referred to as "recesses 220".

[0024] Figure 6 is a magnified view of a portion of the wide welding surface 221 (labeled 22b in Figure 5). In the example shown in Figure 6, the vertical distance 225 between the center line of one row 223 of horizontally arranged minute recesses 222 (a dashed line labeled 223) and the center line of the row 223 vertically adjacent to this row 223 (same as above) is smaller than the diameter of the minute recess 222. That is, when viewed along the horizontal direction, two vertically adjacent rows 223 partially overlap. As a result, in this embodiment, when the end face of the horizontally long horn 313 faces the wide welding surface 221, it will always face one of the minute recesses 222. In the example of Figure 6, the diameter of the minute recess 222 is 0.06 mm, and the vertical distance 225 between the center lines of two horizontally extending and vertically adjacent rows is 0.05 mm. The pitch of the minute recesses 222 in each row 223 is 1.1 mm.

[0025] The lateral distance 226 between the center line of one row 224 of vertically aligned minute recesses 222 (the dashed line labeled 224) and the center line of the row 224 horizontally adjacent to this row 224 (same as above) is also smaller than the diameter of the minute recesses 222. That is, when viewed along the vertical direction, two horizontally adjacent rows 224 partially overlap. In the example in Figure 6, the lateral distance 226 between the center lines of two vertically extending and horizontally adjacent rows is 0.05 mm. Also, the pitch of minute recesses 222 in each row 224 is 1.1 mm.

[0026] The depth of the minute recess 222 is 0.05 mm or more and is less than or equal to the height of the wide projection 22. Preferably, the depth of the minute recess 222 is 5 mm or less. By making the depth of the minute recess 222 0.05 mm or more, welding is prevented or suppressed in the area of ​​the minute recess 222.

[0027] As described above, in the examples shown in Figures 5 and 6, when viewed macroscopically, numerous minute recesses 222 are uniformly distributed on the wide welding surface 221. However, minute recesses 222 are not formed at positions that overlap with the outer edge of the wide welding surface 221. That is, when the wide welding surface 221 is viewed from a direction opposite to the outer surface 21 of the anvil 2, the wide welding surface 221 is present around the entire circumference of each minute recess 222. To put it another way, the wide welding surface 221 is present around the entire circumference of the recess 220, which is a collection of minute recesses 222. This makes the contour of the wide welding region 921 clear. "The wide welding surface 221 is present around the entire circumference of the recess 220" means that all edges of the recess 220 are boundaries with the wide welding surface 221, that is, boundaries with the outermost outer surface of the outer surface 21 that contributes to welding.

[0028] Here, the expressions "the wide welding surface 221 has a recess 220" or "a recess 220 is provided in the wide welding surface 221" consider the recess 220 to be part of the wide welding surface 221, or to be included in the wide welding surface 221. On the other hand, the expression "the wide welding surface 221 exists around the entire circumference of the recess 220" considers the recess 220 to be separate from the wide welding surface 221. Thus, for the sake of explanation, when describing the location of the recess 220, the recess 220 will be considered part of the wide welding surface 221, and when describing the relationship between the area of ​​the recess 220 and the area of ​​the wide welding surface 221 other than the recess 220, the recess 220 and the wide welding surface 221 will be distinguished as separate areas. The same applies to the following explanation.

[0029] In the ultrasonic welding apparatus 1 shown in Figure 1, multiple sheet members 9 are guided to the outer circumferential surface 21 of the anvil 2 by multiple guide rollers 4, overlapping each other. The multiple sheet members 9 pass between the head 31 and the outer circumferential surface 21. That is, between the head 31 and the anvil 2, the multiple sheet members 9 move at the same speed as the outer circumferential surface 21 of the anvil 2 rotates. Furthermore, when the wide welding surface 221 passes below the head 31, ultrasonic vibrations are applied to the multiple sheet members 9 between the head 31 and the wide welding surface 221 by the ultrasonic vibration unit 3, and the area facing the wide welding surface 221 is welded. This forms the wide welding region 921 shown in Figure 4. Also, when the narrow welding surface 231 passes below the head 31, ultrasonic vibrations are applied to the multiple sheet members 9 between the head 31 and the narrow welding surface 231, and the area facing the narrow welding surface 231 is welded. This creates the narrow welding region 931 shown in Figure 4.

[0030] As described above, the wide welding surface 221 is provided with numerous minute recesses 222. If an anvil 2 without minute recesses 222 were used, heat would accumulate in the sheet member 9, causing holes to form in the sheet member 9, making it difficult to uniformly form the wide welding region 921. On the other hand, by providing minute recesses 222 on the wide welding surface 221, ultrasonic vibrations are not transmitted to the sheet member 9 in the region of the minute recesses 222, thus appropriately suppressing the melting of the sheet member 9. This makes it easy to prevent holes from forming in the laminated sheet member 90, and allows for easy welding over a wide area.

[0031] In particular, as shown in the example in Figure 3, when the wide welding surface 221 and the narrow welding surface 231 are aligned in a direction parallel to the central axis J1, that is, when the wide projection 22 and the narrow projection 23 are aligned in a direction parallel to the central axis J1, it becomes difficult to adjust the distance between the head 31 and the anvil 2 to form an appropriate wide welding region 921 and a narrow welding region 931 if the minute recess 222 is not present. In the ultrasonic welding apparatus 1, by providing the minute recess 222 on the wide welding surface 221, even when the wide welding surface 221 and the narrow welding surface 231 are aligned in a direction parallel to the central axis J1, it is possible to easily and simultaneously form an appropriate wide welding region 921 and a narrow welding region 931 while suppressing insufficient welding or the formation of holes.

[0032] Figure 7 shows another example of the wide welding surface 221. In the wide welding surface 221 of Figure 7, multiple groove-like recesses 227 are provided instead of the minute recesses 222 of Figure 5. The recesses provided in the wide welding surface 221 are a collection of groove-like recesses 227. Each groove-like recess 227 extends in a direction intersecting the direction parallel to the central axis J1. Note that the number of groove-like recesses 227 may be greater than the example shown in Figure 7, and if the wide welding surface 221 is small, only a few groove-like recesses 227 may be provided as in Figure 7. If the recess 220 is a collection of grooves, the maximum width of the recess 220 shall be determined as the width of the grooves. The minimum width of the wide welding surface 221 is 5 mm or more, and the maximum width of the groove-like recesses 227 is 1 mm or less.

[0033] Figure 8 shows yet another example of the wide welding surface 221. In the wide welding surface 221 of Figure 8, a grid-like recess 220 is provided instead of the minute recess 222 of Figure 5. Each groove constituting the grid extends in a direction intersecting the direction parallel to the central axis J1. Note that the grid of the recess 220 may be denser than in the example shown in Figure 8. When the recess 220 is grid-like, the maximum width of the recess 220 shall be determined by the width of the grooves constituting the grid. The minimum width of the wide welding surface 221 is 5 mm or more, and the maximum width of the recess 220 is 1 mm or less.

[0034] Figure 9 shows an example where each groove-shaped recess 227 in Figure 7 does not overlap with the outer edge of the wide welding surface 221. In Figure 9, when the wide welding surface 221 is viewed from a direction opposite to the outer surface 21, the wide welding surface 221 is present around the entire circumference of the recess 220. This makes the contour of the wide welding region 921 clearer. In the case of the grid-like recess 220 in Figure 8, the recess 220 may also be made so that the wide welding surface 221 is present around the entire circumference of the recess 220 by making sure that the recess 220 does not overlap with the outer edge of the wide welding surface 221.

[0035] The above description of the ultrasonic welding apparatus 1 is merely illustrative, and the ultrasonic welding apparatus 1 may be modified in various ways.

[0036] In the above embodiment, the outer circumferential surface 21 of the anvil 2 includes a narrow projection 23 that has the same height as the wide projection 22 and a maximum width of 2 mm or less, and the wide projection 22 and the other projection, the narrow projection 23, are aligned in a direction parallel to the central axis J1. "Aligned in a direction parallel to the central axis J1" means that there exists a straight line parallel to the central axis J1 that intersects both the wide projection 22 and the narrow projection 23. The wide projection 22 and the other projection, the narrow projection 23, do not have to be aligned in a direction parallel to the central axis J1, and furthermore, the narrow projection 23 does not have to exist. Even in such cases, by providing a recess 220 on the wide welding surface 221, which is the tip surface of the wide projection 22, a wide area can be stably welded.

[0037] To easily achieve proper welding over a wide area, the recesses 220 are arranged so that, when viewed macroscopically, they are uniformly present on the wide welding surface 221, as illustrated in Figures 5 to 9. "Macroscopically" means viewing the pattern of the recesses 220 over a wide area. Furthermore, as explained with reference to Figure 6, when a straight line parallel to the central axis J1 is drawn on the wide welding surface 221, the recesses 220 (micro-recesses 222) are formed so that this line always and intermittently overlaps with the recesses 220 (micro-recesses 222). The same applies to other recesses 220 illustrated in Figures 7 to 9. Here, excluding the outer edge of the wide welding surface 221, the length between recesses 220 on any straight line parallel to the central axis J1 (the length of each line segment that does not overlap with the recesses 220) is preferably 5 to 500 times the length of the recesses 220 on that straight line (the length of each line segment that overlaps with the recesses 220). This allows for stable and easy welding over a wide area. More preferably, the length between the recesses 220 is 10 to 50 times the length of the recesses 220 along the straight line. In the example shown in Figure 6, the length between the recesses 220 is approximately 15 to 25 times the length of the recesses 220 along the straight line parallel to the central axis J1.

[0038] Furthermore, as already explained, the maximum width of the recess 220 is 1 mm or less, and from a technical standpoint in processing, the maximum width of the recess 220 is 0.01 mm or more. In order to make the trace of the recess 220 difficult to recognize in the wide welding area 921, the maximum width of the recess 220 is preferably 0.1 mm or less, and in order to make the trace of the recess 220 difficult to recognize under various conditions, the maximum width of the recess 220 is preferably 0.07 mm or less. Also, from a technical standpoint, the maximum width of the recess 220 is 0.03 mm or more.

[0039] The minimum width of the wide welding surface 221 is preferably 5 mm or more, but there is no particular upper limit. Depending on the output of the transducer 311, when joining thin sheet members 9, especially when joining nonwoven fabrics, the upper limit of the minimum width of the wide welding surface 221 is about 30 mm. However, by using a transducer 311 with a high output, the minimum width of the wide welding surface 221 in the direction of the central axis J1 of the anvil 2 can be increased to the length in the direction of the central axis J1 (the length in the direction parallel to the sheet member 9 and perpendicular to the transport direction). In addition, the wide welding surface 221 can be made continuous in the circumferential direction of the outer surface 21 of the anvil 2. Depending on the embodiment, multiple horns can be placed side by side in the direction of the central axis J1 of the anvil 2.

[0040] The wide welding surface 221 can also be provided on the entire outer circumferential surface 21 of the anvil 2. In this case, the concept of a wide projection 22 is eliminated on the outer circumferential surface 21, and a recess 220 (for example, the recess 220 illustrated in Figures 5 to 9) is formed on the entire outer circumferential surface 21. In other words, the presence of a wide projection 22 is not essential when providing a wide welding surface 221 on the outer circumferential surface 21. Regardless of the presence or absence of a wide projection 22, the outer circumferential surface 21 of the anvil 2 is provided with a (wide) welding surface 221 for welding multiple sheet members 9 to the head 31.

[0041] The depth of the recess 220 is preferably 0.05 mm or more. The "depth of the recess 220" is the difference between the distance from the central axis J1 to the wide welding surface 221 and the distance from the central axis J1 to the bottom of the recess 220. By making the depth of the recess 220 0.05 mm or more, welding of the sheet member 9 in the recess 220 can be stably suppressed. The depth of the recess 220 does not need to be constant. If the wide welding surface 221 is the tip surface of the wide projection 22, the depth of the recess 220 is less than or equal to the height of the wide projection 22, and is preferably 0.2 mm or less. The "height of the wide projection 22" is the difference between the distance from the central axis J1 to the wide welding surface 221 and the distance from the central axis J1 to the area surrounding the wide projection 22. Typically, the height of the wide projection 22 is 1 mm or more and 5 mm or less.

[0042] Since the outer circumferential surface 21 of the anvil 2 is provided with wide projections 22 and recesses 220, the outer circumferential surface 21 is not strictly cylindrical, but rather approximately cylindrical. Multiple sheet members 9 pass between the outer circumferential surface 21 and the head 31 in an overlapping state, and welding is performed with the multiple sheet members 9 sandwiched between the outermost surface of the outer circumferential surface 21, i.e., the welding surface and the end face of the horn 313. The movement speed of the outermost surface and the transport speed of the multiple sheet members 9 are controlled to be the same. As a result, even if the welding surface facing the end face of the horn 313 includes wide and / or narrow welding surfaces, the (wide and narrow) welding areas are accurately formed. In this case, preferably, the welding surface is the tip surface of the projection on the outer circumferential surface 21 of the anvil 2. The length of the outer circumferential surface 21 of the anvil 2 in the direction of the central axis J1 is generally greater than the width of the multiple sheet members 9 and greater than the width of the horn 313, but is not limited to this. The width of the horn 313 may be greater or less than the width of the multiple sheet members 9.

[0043] The multiple sheet members 9 are typically nonwoven fabrics or plastic films. The multiple sheet members 9 may also be other types of sheets that can be welded together by ultrasonic vibrations. Generally, the sheet members 9 are resin sheets. Preferably, the multiple sheet members 9 include nonwoven fabrics. The nonwoven fabrics and plastic films described above are resins that melt due to the heat generated by ultrasonic vibrations.

[0044] The configurations in the above embodiments and each modified example may be combined as appropriate, as long as they do not contradict each other. [Explanation of Symbols]

[0045] 1 Ultrasonic welding device 2 Anvils 3. Ultrasonic vibration unit 9 Sheet material 21 Outer surface 22. Wide projection (projection) 23 Narrow protrusions (other protrusions) 31 heads 220 recess 221 Wide welding surface 222 Micro-recesses J1 center axis

Claims

1. An ultrasonic welding device, An anvil having a cylindrical outer surface centered on a central axis and rotating about the central axis, The anvil has a head facing the outer circumferential surface, and an ultrasonic vibration unit that welds a plurality of sheet members passing between the head and the outer circumferential surface, Equipped with, The outer circumferential surface of the anvil has a welding surface that welds the plurality of sheet members together with the head, The minimum width of the welded surface is 5 mm or more. An ultrasonic welding apparatus characterized in that the welding surface has a recess which is a collection of granular minute recesses with a maximum width of 0.1 mm or less.

2. An ultrasonic welding apparatus, An anvil having a cylindrical outer surface centered on a central axis and rotating about the central axis, The anvil has a head facing the outer circumferential surface, and an ultrasonic vibration unit that welds a plurality of sheet members passing between the head and the outer circumferential surface, Equipped with, The outer circumferential surface of the anvil has a welding surface that welds the plurality of sheet members together with the head, The minimum width of the welded surface is 5 mm or more. An ultrasonic welding apparatus characterized in that the welding surface has a recess which is a collection of groove-like recesses with a maximum width of 0.1 mm or less.

3. An ultrasonic welding apparatus according to claim 1 or 2, An ultrasonic welding apparatus characterized in that, when the welding surface is viewed from a direction opposite to the outer peripheral surface of the anvil, the welding surface is present around the entire circumference of the recess.

4. An ultrasonic welding apparatus according to claim 1 or 2, The welding surface is the tip surface of the projection on the outer circumferential surface of the anvil, An ultrasonic welding apparatus characterized in that the outer circumferential surface of the anvil includes other protrusions that are the same height as the protrusion and have a maximum width of 2 mm or less, and the protrusion and the other protrusions are aligned in a direction parallel to the central axis.

5. An ultrasonic welding apparatus according to claim 1 or 2, When viewed macroscopically, the recesses are uniformly distributed on the welded surface. An ultrasonic welding apparatus characterized in that, excluding the outer edge of the welding surface, the length between recesses on a straight line parallel to the central axis is 5 times or more and 500 times or less the length of the recess on the said straight line.

6. An ultrasonic welding apparatus according to claim 1 or 2, An ultrasonic welding apparatus characterized in that the depth of the recess is 0.05 mm or more.

Images