Ultrasonic coupling device

Abstract

To securely join workpieces while suppressing structural complexity. [Solution] An ultrasonic bonding apparatus comprising a horn 1 and an anvil 2 that clamps a plurality of workpieces 3, 4 in a first direction, wherein the horn 1 vibrates in a second direction perpendicular to the first direction, and the anvil 2 comprises a support 10 and an oscillating body 11 that abuts against the workpiece 4 and is supported by the support 10 so as to be rotatable about a pivot axis 16 along a third direction perpendicular to the first and second directions, and vibrates at the same frequency as the horn 1 but with a different phase.

Description

Technical Field

[0001] The present invention relates to an ultrasonic bonding device for bonding a plurality of workpieces by ultrasonic vibration.

Background Art

[0002] When bonding a plurality of workpieces by ultrasonic vibration, the plurality of workpieces are clamped, for example, vertically by a horn and an anvil. Then, by vibrating the horn in the lateral direction, the plurality of workpieces are bonded together (see Patent Document 1 below). However, for example, when the plurality of workpieces are made of different metals, that is, in the case of bonding different metals, the bonding strength is likely to be insufficient, and there is also a possibility of damaging the workpieces. Also, when bonding a multilayer electrode foil and a current collector tab employed in a large-sized battery, it is not easy to bond all of the multilayer electrode foils to the current collector tab.

[0003] On the other hand, as in Patent Document 2 below, there is also a device in which horns are respectively arranged on both sides of a workpiece, but the structure becomes complicated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to improve the bonding strength between workpieces while suppressing the complication of the structure.

Means for Solving the Problems

[0006] The ultrasonic bonding apparatus according to the present invention comprises a horn and an anvil for clamping a plurality of workpieces in a first direction, wherein the horn vibrates in a second direction perpendicular to the first direction, and the anvil comprises a support body and an oscillating body that contacts the workpiece and is supported by the support body so as to be rotatable about a pivot axis along a third direction perpendicular to the first and second directions, and vibrates at the same frequency as the horn but with a different phase.

[0007] In this configuration, the anvil is equipped with an oscillating body. The oscillating body is rotatably supported by a support. When the horn vibrates, the oscillating body swings like a pendulum around a rotation axis along a third direction. The frequency of the oscillating body's vibration is the same as the frequency of the horn's vibration. On the other hand, the phase of the oscillating body's vibration is different from the phase of the horn's vibration. As a result, frictional heat is generated between the workpieces, causing them to join together.

[0008] In particular, the horn has a horn contact portion that contacts the workpiece, and the oscillating body has an anvil contact portion that contacts the workpiece. When viewed in a third direction, it is preferable that the horn contact portion, the anvil contact portion, and the rotation axis are aligned in a straight line along the first direction. With this configuration, the anvil contact portion can be efficiently vibrated along the second direction, and the amplitude of the anvil contact portion can be easily secured. Moreover, the vibration of the anvil contact portion is more stable. As a result, the bonding strength between workpieces can be further increased, damage to the workpieces can be further avoided, and workpieces can be joined together more reliably.

[0009] Furthermore, it is preferable to have a limiting stopper that faces the oscillating body with a gap in between, and which contacts the oscillating body to limit its amplitude when the amplitude exceeds a certain level. With this configuration, if the oscillating body attempts to vibrate in phase with the horn, the limiting stopper contacts the oscillating body and restricts its vibration. As a result, the oscillating body is prevented from vibrating in phase with the horn, and the oscillating body can be reliably vibrated in a different phase from the horn. In addition, the vibration of the oscillating body can be easily stabilized.

[0010] In particular, the oscillating body has an oscillating base portion extending in a second direction at the end on the support side in a first direction, and the limiting stopper is provided on the support and preferably abuts against the end of the oscillating base portion in the second direction in the first direction. With this configuration, by providing the limiting stopper on the support, the placement of the limiting stopper becomes easier. Furthermore, an oscillating base portion extending in a second direction is provided at the end on the support side in the first direction of the oscillating body, and the limiting stopper abuts against the end of the oscillating base portion in the second direction in the first direction. Therefore, setting and managing the gap between the oscillating body and the limiting stopper becomes easier, and even if the vibration of the oscillating body is minute, the limiting stopper can be properly abutted against the oscillating body. Consequently, it is easy to prevent the oscillating body from vibrating in phase with the horn, and vibration control of the oscillating body becomes easier.

[0011] Furthermore, it is preferable that the limiting stopper is provided on the support so as to be adjustable in a first direction. With this configuration, vibration control of the oscillating body becomes even easier by adjusting the position of the limiting stopper in the first direction.

[0012] Furthermore, the horn has a horn contact portion that contacts the workpiece, and the oscillating body has an anvil contact portion that contacts the workpiece, and it is preferable that the amplitude of the anvil contact portion in the second direction is smaller than the amplitude of the horn contact portion in the second direction. With this configuration, since the amplitude of the anvil contact portion in the second direction is smaller than the amplitude of the horn contact portion in the second direction, the vibration of the oscillating body is more stable, and the oscillating body is less likely to vibrate in phase with the horn.

[0013] On the other hand, the amplitude of the anvil contact portion in the second direction is preferably 20% or more of the amplitude of the horn contact portion in the second direction. With this configuration, the workpieces can be reliably joined together, and the joint strength can be easily ensured.

[0014] Furthermore, the amplitude of the anvil contact portion in the second direction is preferably 5 μm or more in terms of PP value (peak-to-peak value). This configuration allows for more reliable joining of workpieces and makes it easier to ensure joint strength.

[0015] Also, an anvil of an ultrasonic bonding apparatus according to the present invention is an anvil of an ultrasonic bonding apparatus that sandwiches a plurality of workpieces in a first direction together with a horn that vibrates in a second direction orthogonal to the first direction, and includes a support body, and a rocking body that abuts against the workpiece and is supported by the support body so as to be rotatable about a rotation axis along a third direction orthogonal to the first direction and the second direction, and that vibrates at the same vibration frequency as the horn and with a different phase.

Effect of the Invention

[0016] As described above, since the anvil is provided with a rocking body that rocks about the rotation axis at the same vibration frequency as the horn and with a different phase, the workpieces can be reliably bonded with a simple structure.

Brief Description of the Drawings

[0017] [Figure 1] Perspective view showing an anvil of an ultrasonic bonding apparatus in an embodiment of the present invention. [Figure 2] Plan view of the anvil. [Figure 3] Front view of the anvil. [Figure 4] Front view of a main part showing a bonding state of a workpiece by the apparatus. <00000​​​​​​​​​​​​​​​​​​​​​​​​​​​Plan view of the support table. [Figure 15] Front view showing the anvil of an ultrasonic bonding apparatus in another embodiment of the present invention. [Modes for carrying out the invention]

[0018] The ultrasonic bonding apparatus according to one embodiment of the present invention will be described below with reference to Figures 1 to 14. The ultrasonic bonding apparatus (hereinafter simply referred to as the apparatus) comprises a horn 1 and an anvil 2 arranged to face each other in the vertical direction, as shown in Figures 1 to 4. In the following description, the first direction will be defined as the vertical direction, the second direction perpendicular to the first direction will be defined as the left-right direction, and the third direction perpendicular to both the first and second directions will be defined as the front-back direction. In the figures, the vertical direction, left-right direction, and front-back direction are indicated by arrows Z, X, and Y, respectively. However, the directions from the first to the third direction may be arbitrary.

[0019] The device joins multiple workpieces together. The workpieces are typically made of metal or resin. The device is particularly suitable for joining metals together, and also for joining dissimilar metals. Examples include joining multilayer foil electrodes, electrode tabs, electrode busbars, and clad electrode components.

[0020] In this embodiment, multiple workpieces are designated as the first workpiece 3 and the second workpiece 4. The first workpiece 3 and the second workpiece 4 are stacked on top of each other. For example, the first workpiece 3 is stacked on top of the second workpiece 4. The stacked first workpiece 3 and second workpiece 4 are placed on the anvil 2. The first workpiece 3 and the second workpiece 4 are held between the horn 1 and the anvil 2 from above and below, as shown in Figure 4. Therefore, the horn 1 abuts against the upper surface of the first workpiece 3, and the anvil 2 abuts against the lower surface of the second workpiece 4. The horn 1 presses the first workpiece 3 and the second workpiece 4 downwards. The anvil 2 supports the first workpiece 3 and the second workpiece 4 from below. Therefore, the first workpiece 3 and the second workpiece 4 receive a downward force from the horn 1 and an upward force from the anvil 2.

[0021] Horn 1 is equipped with a horn tip 5. The tip of the horn tip 5 faces downward. That is, the horn tip 5 faces towards the anvil 2. The horn tip 5 has a horn contact portion 6 on its tip surface, i.e., its lower end surface, which contacts the first workpiece 3. The horn contact portion 6 is formed over the entire lower end surface of the horn tip 5. The horn contact portion 6 is a plane whose normal direction is in the vertical direction. Preferably, the horn contact portion 6 has a large number of fine irregularities, which can increase the frictional resistance between the horn contact portion 6 and the first workpiece 3.

[0022] The horn contact portion 6 vibrates in the left-right direction. Note that the horn contact portion 6 only needs to vibrate in the left-right direction; it may also vibrate in the front-back direction, etc. The resonant frequency of the horn contact portion 6 can vary and can be set to any frequency. The amplitude of the horn contact portion 6 may also be settable. The device is servo-driven and includes a servo motor (not shown).

[0023] <Anvil 2> Anvil 2 is positioned directly below the horn contact portion 6. The device includes a horizontal mounting table 7, as shown by the dashed lines in Figures 1 and 3. Anvil 2 is detachably mounted to the top surface of the mounting table 7, for example, by screws from above.

[0024] <Support> Anvil 2 comprises a support table 10 as a support and a swinging body 11 supported by the support table 10. The support table 10 is attached to and fixed to the mounting table 7. Specifically, the support table 10 is screwed to the upper surface of the mounting table 7. Figure 13 shows a plan view of the support table 10. The support table 10 is rectangular in plan view, and more specifically, it is a rectangle that is elongated in the left-right direction in plan view. The support table 10 is symmetrical. Mounting holes 12 that penetrate vertically are formed at the four corners of the support table 10. The support table 10 is screwed to the mounting table 7 from above through the mounting holes 12.

[0025] As shown in Figures 5 and 13, a lower groove 13 is formed on the upper surface of the support table 10, recessed downwards in the center in the left-right direction. The lower groove 13 runs along the front-rear direction. The lower groove 13 is formed along the entire length of the support table 10 in the front-rear direction. Therefore, the lower groove 13 opens on the upper surface of the support table 10 as well as on both the front and rear surfaces of the support table 10. As shown in Figures 5 and 14, a lower support rod 14 is fitted into the lower groove 13. In Figure 14, the lower support rod 14 is indicated by numerous dots. The lower support rod 14 is screwed to the support table 10 from below. The length of the lower support rod 14 in the front-rear direction is the same as that of the support table 10.

[0026] A lower support surface 15 is provided on the upper surface of the lower support rod 14. The lower support surface 15 extends across the entire upper surface of the lower support rod 14. The lower support surface 15 is a curved surface that curves along the left-right direction, and in a cross-sectional view as shown in Figure 5, it curves upward in an arc shape. The lower support surface 15 is arc-shaped in cross-section, and its center in the cross-sectional view is the rotation axis 16 along the front-rear direction. The rotation axis 16 is located in the left-right center of the lower support rod 14, and therefore, in the left-right center of the support table 10. The support table 10 and the lower support rod 14 have a left-right symmetrical shape with the rotation axis 16 as the axis of symmetry in a plan view as shown in Figure 14. The lower support surface 15 is highest at the center in the left-right direction, and this position is the top. The radius of curvature of the lower support surface 15 is arbitrary. In this embodiment, the radius of curvature of the lower support surface 15 is smaller than the vertical dimension of the lower support rod 14, but it may be the same as or larger than the vertical dimension of the lower support rod 14.

[0027] The upper surface of the support table 10 is provided with a lower opposing surface 17. The lower opposing surface 17 is parallel to the lower surface of the support table 10 and is a horizontal plane. The lower opposing surfaces 17 are provided on both the left and right sides of the lower groove 13. The lower support surface 15 protrudes above the lower opposing surface 17 at its uppermost point 15a, and the uppermost point 15a of the lower support surface 15 is located above the lower opposing surface 17.

[0028] The upper surface of the support table 10 is provided with stepped lower surfaces 18 at both the left and right ends, which are one step lower than the lower opposing surface 17. The stepped lower surfaces 18 are provided adjacent to the left and right outer sides of the lower opposing surface 17. The stepped lower surfaces 18 are formed along the entire length of the support table 10 in the front-to-back direction. The stepped lower surfaces 18 are horizontal. The mounting holes 12 described above are provided on the stepped lower surfaces 18.

[0029] On both the left and right sides of the support table 10, notched grooves 19 are formed, which are cut out inward in a plan view. The notched grooves 19 extend along the vertical direction and penetrate in the vertical direction. Therefore, the notched grooves 19 open to both the left and right sides, as well as to the lower surface of the support table 10 and the lower surface 18 of the step.

[0030] <Restriction Stopper 20> The device is equipped with limiting stoppers 20. The limiting stoppers 20 control the vibration of the oscillating body 11. The limiting stoppers 20 face the oscillating body 11 with a gap between them, and when the amplitude of the oscillating body 11 exceeds a certain level, they contact the oscillating body 11 to limit its amplitude and restrict the oscillating body 11 from vibrating in phase with the horn 1. The limiting stoppers 20 are provided on the anvil 2. A pair of limiting stoppers 20 are provided, one on the left and one on the right, and are attached to the left and right sides of the support table 10, respectively. The limiting stoppers 20 are screwed to the sides of the support table 10. Therefore, the limiting stoppers 20 can be positioned vertically by the gap between the mounting holes (not shown) for screwing the limiting stoppers 20 to the support table 10 and the screws. The upper surface 20a of the limiting stopper 20 is the stopper surface, and the height of this stopper surface can be adjusted, thereby adjusting the vertical gap between the stopper surface and the oscillating body 11. The left and right pair of limiting stoppers 20 are each independently height-adjustable. The limiting stoppers 20 cover the notched groove 19 from the outside.

[0031] <Oscillating body 11> The oscillating body 11 is provided on the upper side of the support table 10, specifically resting on the lower support rod 14. The oscillating body 11 is pivotably supported on the support table 10. The oscillating body 11 rotates like a pendulum in the left-right direction around the rotation axis 16. As described above, the rotation axis 16 is the center in the cross-sectional view of the lower support surface 15 and is located directly below the horn contact portion 6. The horn contact portion 6 and the rotation axis 16 are aligned on the same line along the vertical direction. Figure 8 shows an exaggerated rotational movement of the oscillating body 11. In Figure 8, the rotation angle of the oscillating body 11 is shown as larger than the actual rotation angle. Figure 8(a) shows the oscillating body 11 in an upright position, not tilted to the left or right. Figure 8(b) shows the state when the oscillating body 11 is tilted to the left from an upright position, and Figure 8(c) shows the state when the oscillating body 11 is tilted to the right from an upright position. However, the actual rotation angle of the oscillating body 11 is slight, less than 1 degree in the total swing angle in the left-right direction, and more specifically less than 0.1 degrees.

[0032] The rocking body 11 includes a rocking table 30 as a rocking base. The rocking table 30 is placed on top of the support table 10 and faces the support table 10. Figure 10 shows a plan view of the rocking table 30, and Figures 11 and 12 show bottom views of the rocking table 30. The rocking table 30, like the support table 10, has a symmetrical shape. The rocking table 30 has a table body 31 and a pair of left and right extensions 32 that protrude outward in the left and right directions from both ends of the table body 31. The table body 31 is rectangular in plan view, and more specifically, it is a rectangle that is long in the front-to-back direction. The extensions 32 protrude outward from the front-to-back center of both ends of the table body 31. The front-to-back dimension of the extensions 32 is smaller than the front-to-back dimension of the table body 31. The presence of a pair of left and right extension sections 32 makes the overall length of the rocking table 30 in the left-right direction longer than its overall length in the front-back direction. The thickness (vertical dimension) of the extension sections 32 is smaller than that of the table body 31.

[0033] As shown in Figures 3, 5, and 11, an upper groove 33 is formed in the center of the lower surface of the rocking table 30 in the left-right direction, and is recessed upwards. The upper groove 33 is opposite to the lower groove 13 of the support table 10. The upper groove 33 is oriented in the front-rear direction and reaches both the front and rear surfaces of the rocking table 30. Therefore, the upper groove 33 opens to the upper surface of the rocking table 30 as well as to both the front and rear surfaces of the rocking table 30.

[0034] An upper support rod 34 is fitted into the upper groove 33. In Figure 12, the upper support rod 34 is shown with numerous dots. A pair of upper support rods 34 are provided, one on the left and one on the right. The pair of upper support rods 34 are arranged symmetrically. The pair of upper support rods 34 are identical parts and are used by reversing their front and back orientations. The upper support rods 34 are screwed to the rocking table 30 from above. The length of the upper support rods 34 in the front-to-back direction is the same as that of the rocking table 30. The upper support rods 34 are opposite the lower support rod 14 in the vertical direction.

[0035] An upper support surface 35 is provided on the lower surface of the upper support rod 34. The upper support surface 35 is provided on the entire lower surface of the upper support rod 34. The upper support surface 35 is a curved surface that curves along the left-right direction, and in a cross-sectional view as shown in Figure 5, it curves downward in an arc shape. The upper support surface 35 abuts against the lower support surface 15. The contact state between the upper support surface 35 and the lower support surface 15 is a line contact along the front-rear direction, and is a point contact in a cross-sectional view. The left and right pair of upper support surfaces 35 each make point contact with the lower support surface 15 at one point in a cross-sectional view. Therefore, the left and right pair of upper support surfaces 35 make point contact with the lower support surface 15 at a total of two points in a cross-sectional view. The contact points 36 between the upper support surface 35 and the lower support surface 15 in a cross-sectional view are offset in the left-right direction with respect to the rotation axis 16, and the left and right contact points 36 are provided symmetrically with respect to the rotation axis 16. The left and right contact points 36 are separated in the circumferential direction of the lower support surface 15. The rocking table 30 is supported by the lower support surface 15 at two points in cross-sectional view. When the rocking table 30 rotates from side to side, the upper support surface 35 slides along the lower support surface 15 in its circumferential direction while making contact with the lower support surface 15 at two points in cross-sectional view.

[0036] An upper opposing surface 37 is provided on the lower surface of the oscillating table 30. The upper opposing surface 37 is located above the lower opposing surface 17 of the support table 10. When the oscillating body 11 is in an upright position and not tilted to the left or right, as shown in Figures 3 and 5, the upper opposing surface 37 is parallel to the lower opposing surface 17 and is horizontal. A vertical gap is provided between the upper opposing surface 37 and the lower opposing surface 17. The upper opposing surface 37 is provided adjacent to both the left and right sides of the upper groove 33. The upper opposing surface 37 is provided on the entire lower surface of the table body 31 except for the upper groove 33, and is continuous up to partway down the lower surface of the extension 32.

[0037] The upper support surface 35 has a portion that protrudes downward from the lower opposing surface 17. The majority of the upper support surface 35 protrudes downward from the lower opposing surface 17. The upper opposing surface 37 has screw recesses 38 formed facing upward. The screw recesses 38 are round holes, which are counterbore holes. There is a pair of screw recesses 38 on both the left and right sides of the upper groove 33.

[0038] Restricting surfaces 39 are provided at both the left and right ends of the lower surface of the rocking table 30. The restricting surfaces 39 are adjacent to the left and right outer sides of the upper opposing surface 37. The restricting surfaces 39 are located one step below the upper opposing surface 37. The restricting surfaces 39 are parallel to the upper opposing surface 37. The restricting surfaces 39 are not provided on the lower surface of the table body 31, but only on the lower surface of the extension portion 32. The restricting surfaces 39 are provided at the tip of the extension portion 32 in the protruding direction. The restricting surfaces 39 are located above the stepped lower surface 18 of the upper surface of the support table 10.

[0039] As shown in Figures 6 and 7, the restricting surface 39 of the oscillating table 30 faces the upper surface 20a of the limiting stopper 20. A small gap is provided between the upper surface 20a of the limiting stopper 20 and the restricting surface 39 of the oscillating table 30. This gap can be adjusted by adjusting the position of the limiting stopper 20 vertically. The gap is 1 mm or less, preferably 0.1 mm or less. The gap can be arbitrarily set within a range of, for example, several tens of micrometers to several hundred micrometers.

[0040] Furthermore, when the rocking table 30 is in an upright position, both of the left and right limiting stoppers 20 may be slightly elevated above the restricting surface 39 of the rocking table 30, or only one of the left and right limiting stoppers 20 may be slightly elevated above the restricting surface 39 of the rocking table 30, while the other is in contact with the restricting surface 39 of the rocking table 30. When the rocking table 30 is in an upright position, it is sufficient that at least one of the left and right limiting stoppers 20 faces the restricting surface 39 with a gap between them.

[0041] When the rocking table 30 rocks, the restricting surface 39 of the rocking table 30 comes into contact with the upper surface 20a of the limiting stopper 20. By the restricting surface 39 of the rocking table 30 coming into contact with the upper surface 20a of the limiting stopper 20, further downward tilting of the rocking table 30 is prevented. In other words, the amplitude of the rocking table 30 is restricted compared to when the limiting stopper 20 is not provided. If the amplitude of the rocking table 30 when the limiting stopper 20 is not provided is called the unlimited amplitude, then with the provision of the limiting stopper 20, the amplitude of the rocking table 30 becomes smaller than the unlimited amplitude.

[0042] A spring support surface 40 is provided on the upper surface of the rocking table 30. A pair of spring support surfaces 40 are provided on the left and right sides. A notched recess 41 for the spring is provided in the center of the upper surface of the table body 31 in the front-rear direction, opening upward and outward in the left-right direction. A spring support surface 40 is provided on the bottom surface of the notched recess 41. The spring support surface 40 is located one level above the upper surface of the extension portion 32 and is provided parallel to the upper surface of the extension portion 32.

[0043] An intermediate base 50 is provided above the oscillating table 30, and an anvil body 51 is provided above the intermediate base 50. The intermediate base 50 is screwed to the upper surface of the oscillating table 30, and the anvil body 51 is attached to the upper surface of the intermediate base 50. The anvil body 51, intermediate base 50, and oscillating table 30 oscillate together as a single unit. Thus, the oscillating table 30, intermediate base 50, and anvil body 51 are separate structures and components, but they may also be a single integrated structure or composed of a single component. The intermediate base 50 may be omitted. In this way, the number of components of the oscillating body 11 is arbitrary.

[0044] The anvil body 51 has a main part 52 and a tip part 53, as shown in Figures 1 to 5. The main part 52 is placed on the upper surface of the intermediate base 50. The main part 52 is a rectangular parallelepiped, but its shape is arbitrary. The tip part 53 protrudes upward from the upper surface of the main part 52. The tip part 53 is smaller than the main part 52. The shape of the tip part 53 is arbitrary, but for example, it is a rectangular parallelepiped that is long in the front-to-back direction when viewed from above. An anvil contact part 54 is provided on the upper surface of the tip part 53. The anvil contact part 54 is provided on the entire upper surface of the tip part 53. The shape of the anvil contact part 54 may also vary, but in this embodiment, it is long in the front-to-back direction, specifically, it is a long rectangle in the front-to-back direction.

[0045] The anvil contact portion 54 contacts the second workpiece 4. The anvil contact portion 54 is a plane with its normal direction in the vertical direction, and the anvil contact portion 54 and the horn contact portion 6 face each other vertically and are parallel to each other. Preferably, the anvil contact portion 54 has many fine irregularities formed on it, which can increase the frictional resistance between the anvil contact portion 54 and the second workpiece 4.

[0046] The anvil contact portion 54 and the horn contact portion 6 are separated vertically from each other in the state before workpiece joining as shown in Figure 3, and become close to each other when workpiece joining is performed as shown in Figure 4. As shown in Figures 3 to 5, the horn contact portion 6, the anvil contact portion 54, and the pivot axis 16 are aligned in a straight line along the vertical direction. In the front view as shown in Figure 3 and the cross-sectional view as shown in Figure 5, the straight line along the vertical direction passing through the pivot axis 16 is the center line 2a of the anvil 2. The center line 2a passes through the center of the horn contact portion 6 and the anvil contact portion 54 in the left-right direction. The horn contact portion 6, the anvil contact portion 54, and the pivot axis 16 are located on the center line 2a.

[0047] As shown in Figures 1 and 2, the anvil 2 is equipped with side covers 60. A pair of side covers 60 are provided, one at the front and one at the rear, and they are identical in shape and arranged symmetrically. Note that in the front view shown in Figure 3, the side covers 60 are not shown and are shown in a state with the side covers 60 removed. The side covers 60 are formed in a gate shape and can be screwed to the support table 10 at two points and to the rocking table 30 at two points. The side covers 60 are screwed to either the support table 10 or the rocking table 30, but in Figures 1 and 2, the side covers 60 are shown attached to the rocking table 30. The side covers 60 cover both the front and rear ends of the upper support rod 34. The side covers 60 restrict the movement of the upper support rod 34 in the front-rear direction. That is, the side covers 60 can prevent the upper support rod 34 from shifting outward in the front-rear direction due to vibration. Note that the shape of the side covers 60 is arbitrary and may be a rectangle that is long in the left-right direction, rather than a gate shape. Furthermore, the side cover 60 may be omitted.

[0048] <Spring> A spring is interposed between the support table 10 and the oscillating table 30. The oscillating table 30 is connected to the support table 10 via the spring. The springs are arranged symmetrically on both the left and right sides of the upper support rod 34 and the lower support rod 14. Various types of springs may be used, but in this embodiment, a leaf spring with the thickness direction in the vertical direction is used, and it is a flat plate without any bends. The leaf spring is made of metal.

[0049] In this embodiment, as shown in Figures 5 to 7, an upper spring 70 and a lower spring 71 are provided as springs. A pair of upper springs 70 are provided on the left and right sides, and a pair of lower springs 71 are also provided on the left and right sides. Both the upper springs 70 and the lower springs 71 are located in the center in the front-rear direction and are in an upward-downward positional relationship with each other. Therefore, in a plan view, the upper springs 70 and the lower springs 71 are arranged on the same line along the left-right direction and are located on the center line along the left-right direction of the anvil 2. Note that the springs may consist of only the upper springs 70 or only the lower springs 71. Figure 9 shows an exploded view, in which a spring retainer 72 is provided on the upper side of the upper spring 70.

[0050] <Upper spring 70> The upper spring 70 is connected to the upper surface of the rocking table 30 and applies a vertical spring force to the upper surface of the rocking table 30. The upper spring 70 has an upper fixed end 70a connected to the support table 10 at one end in the left-right direction, and an upper working end 70b connected to the rocking table 30 at the other end in the left-right direction. In this embodiment, the upper fixed end 70a is provided at the outer end of the upper spring 70 in the left-right direction, and the upper working end 70b is provided at the inner end of the upper spring 70 in the left-right direction. The width of the upper fixed end 70a is narrower than the width of the upper working end 70b. That is, the front-rear dimension of the upper fixed end 70a is smaller than that of the upper working end 70b, and the upper spring 70 is formed in a substantially T-shape.

[0051] Support columns 73 extending in the vertical direction are attached to the stepped lower surface 18 of the upper surface of the support table 10. There are two pairs of support columns 73, one in the front and one in the back, on each of the left and right stepped lower surfaces 18 of the support table 10. The front and rear pair of support columns 73 are located on both the front and rear sides of the extension portion 32 of the rocking table 30. The upper end surfaces of the support columns 73 are located slightly above the upper surface of the extension portion 32 of the rocking table 30. The upper fixed end 70a of the upper spring 70 is screwed from above to the upper end surfaces of the front and rear pair of support columns 73. The upper fixed end 70a is screwed to the front and rear pair of support columns 73 at both the front and rear ends, so as to straddle the extension portion 32 of the rocking table 30 from above in the front and rear direction.

[0052] In this way, the upper spring 70 is connected to the support table 10 via the support column 73. The height of the support column 73 is higher than the upper surface of the extension portion 32 of the rocking table 30. Therefore, there is a gap between the upper fixed end 70a of the upper spring 70 and the upper surface of the extension portion 32 of the support table 10. A spring retainer 72, which has a shape corresponding to the upper fixed end 70a, is placed on the upper surface of the upper fixed end 70a, and the upper fixed end 70a is screwed to the support column 73 together with the spring retainer 72. The spring retainer 72 is made of metal, is a flat plate, and is a rectangle that is long in the front-to-back direction.

[0053] The upper working end 70b of the upper spring 70 is connected to the upper surface of the rocking table 30. Specifically, the upper working end 70b of the upper spring 70 enters a notched recess 41 of the rocking table 30 and is screwed from above to the spring support surface 40 of the rocking table 30. The spring support surface 40 is located above the upper end surface of the support column 73. Therefore, as shown in Figure 6, the height of the upper working end 70b of the upper spring 70 is higher than the height of the upper fixed end 70a, and in the initial state, the upper spring 70 is bent upward so that the upper working end 70b is located above the upper fixed end 70a. In this way, in the initial state, the upper spring 70 presses the rocking table 30 downward, biasing the rocking table 30 downward.

[0054] <Lower spring 71> The lower spring 71 is connected to the lower surface of the rocking table 30 and applies a vertical spring force to the lower surface of the rocking table 30. The lower spring 71 is provided separately below the upper spring 70. As shown in Figure 9, the lower spring 71 has the same shape as the upper spring 70, but its orientation is reversed left to right in a plan view. The lower spring 71 has a lower fixed end 71a at one end in the left-right direction that is connected to the support table 10, and a lower working end 71b at the other end in the left-right direction that is connected to the rocking table 30. In this embodiment, the lower fixed end 71a is provided at the inner end of the lower spring 71 in the left-right direction, and the lower working end 71b is provided at the outer end of the lower spring 71 in the left-right direction. The width of the lower fixed end 71a is narrower than the width of the lower working end 71b, and the front-rear dimension of the lower fixed end 71a is smaller than that of the lower working end 71b. The lower spring 71 is formed in a roughly T-shape, similar to the upper spring 70.

[0055] As shown in Figures 6, 7, 13, and 14, the lower fixed end 71a of the lower spring 71 is connected to the upper surface of the support table 10. Specifically, two points at both the front and rear ends of the lower fixed end 71a of the lower spring 71 are screwed to the lower opposing surface 17 of the support table 10 from above. The screw recess 38 of the oscillating table 30 corresponds to the location where the lower fixed end 71a is screwed, and a clearance space is formed on the lower surface of the oscillating table 30 so that the screw heads do not interfere with the oscillating table 30.

[0056] The lower working end 71b of the lower spring 71 is positioned spaced apart above the stepped lower surface 18 of the support table 10. The lower working end 71b of the lower spring 71 is connected to the lower surface of the extension portion 32 of the rocking table 30. More specifically, the lower working end 71b is screwed from below to the restricting surface 39 on the lower surface of the extension portion 32. The point where the lower working end 71b is connected to the extension portion 32 corresponds to the notched groove 19 of the support table 10. In its initial state, the lower spring 71 is in a horizontal position without deflection. The point of application of the spring force of the upper spring 70 on the rocking table 30 and the point of application of the spring force of the lower spring 71 on the rocking table 30 are spaced apart from each other in the left-right direction.

[0057] Furthermore, the upper spring 70 and the lower spring 71 may be made of the same part as described above, or they may be made of different parts. For example, it is preferable to make the upper spring 70 relatively stronger and the lower spring 71 relatively weaker. As an example, the thickness of the upper spring 70 may be made thicker than the thickness of the lower spring 71 to create a difference in spring constant.

[0058] In the apparatus described above, when joining the first workpiece 3 and the second workpiece 4 to each other, as shown by the dashed line in Figure 3, the second workpiece 4 is placed on the anvil contact portion 54 with the horn contact portion 6 spaced upward from the anvil contact portion 54, and the first workpiece 3 is placed on top of it. Alternatively, the first workpiece 3 and the second workpiece 4 are stacked on top of each other beforehand, and then the first workpiece 3 and the second workpiece 4 are placed together on the anvil contact portion 54.

[0059] Then, as shown in Figure 4, the first workpiece 3 and the second workpiece 4 are clamped vertically by the horn contact portion 6 and the anvil contact portion 54. When the horn contact portion 6 and the anvil contact portion 54 clamp the first workpiece 3 and the second workpiece 4, one or both of the horn 1 and the anvil 2 are moved vertically to bring the horn contact portion 6 relatively closer to the anvil contact portion 54. The horn 1 may be lowered, the anvil 2 may be raised, or the horn 1 may be lowered while the anvil 2 is raised. In addition, the horn contact portion 6 may press the first workpiece 3 downwards, the anvil contact portion 54 may press the second workpiece 4 upwards, or both the horn contact portion 6 and the anvil contact portion 54 may press the first workpiece 3 and the second workpiece 4, respectively.

[0060] With the first workpiece 3 and the second workpiece 4 held between the horn contact portion 6 and the anvil contact portion 54, the horn contact portion 6 is vibrated in the left-right direction to join the first workpiece 3 and the second workpiece 4. When the horn contact portion 6 vibrates, the vibration is transmitted to the anvil 2 via the first workpiece 3 and the second workpiece 4. The oscillating table 30 swings like a seesaw relative to the support table 10 with the rotation axis 16 as the pivot point, and the oscillating body 11 swings like a pendulum in the left-right direction with the rotation axis 16 as the pivot point. The swing angle of the oscillating body 11 is small. Therefore, the anvil contact portion 54 effectively vibrates in the left-right direction.

[0061] The vibration frequency of the oscillating body 11, that is, the vibration frequency of the anvil contact portion 54, is the same as the vibration frequency of the horn contact portion 6. On the other hand, the phase of the vibration of the anvil contact portion 54 is different from the phase of the vibration of the horn contact portion 6. Therefore, the anvil contact portion 54 vibrates with the same frequency but at a different phase relative to the horn contact portion 6. The first workpiece 3 vibrates together with the horn contact portion 6, and the second workpiece 4 vibrates together with the anvil contact portion 54. That is, the first workpiece 3 and the second workpiece 4 vibrate together in the left-right direction at the same frequency as each other, but at different phases relative to each other. This results in the first workpiece 3 and the second workpiece 4 being joined together. In this way, since the oscillating body 11 is supported on the support table 10 so as to be rotatable about a rotation axis 16 along the front-rear direction, the anvil contact portion 54 can be made to vibrate in the left-right direction at the same frequency but at a different phase as the horn contact portion 6.

[0062] In particular, if the amplitude of the anvil contact portion 54 is smaller than the amplitude of the horn contact portion 6, the vibration of the anvil contact portion 54 is more stable, and the anvil contact portion 54 is less likely to vibrate in phase with the horn contact portion 6. On the other hand, if the amplitude of the anvil contact portion 54 is 20% or more of the amplitude of the horn contact portion 6, the bonding strength can be easily ensured. Also, if the amplitude of the anvil contact portion 54 is 5 μm or more in terms of PP value, the bonding strength can be easily ensured. Therefore, it is preferable that the amplitude of the anvil contact portion 54 is smaller than the amplitude of the horn contact portion 6, and is 20% or more of the amplitude of the horn contact portion 6, and has a PP value of 5 μm or more.

[0063] Furthermore, in a front view, the horn contact portion 6, the anvil contact portion 54, and the rotation axis 16 are aligned in a straight line on the center line 2a along the vertical direction. Therefore, the anvil contact portion 54 can be vibrated efficiently in the left-right direction, and the vibration of the anvil contact portion 54 is also easily stabilized. In particular, because the oscillating body 11 has a symmetrical shape, the vibration of the anvil contact portion 54 is easily stabilized. In addition, the shape of the oscillating body 11, in a front view, narrows towards the top, and has an overall mountain-like shape. And because the anvil contact portion 54 is located at the top of this mountain-shaped oscillating body 11, the vibration of the anvil contact portion 54 is easily stabilized.

[0064] Furthermore, a limiting stopper 20 is provided on the anvil 2, and the limiting stopper 20 contacts the oscillating body 11 to restrict excessive amplitude of the oscillating body 11. As a result, the oscillating body 11 can be reliably vibrated at a different phase from the horn contact portion 6, and the vibration of the oscillating body 11 can be easily stabilized. In particular, the limiting stopper 20 contacts the oscillating table 30, which corresponds to the base of the V-shaped oscillating body 11 when viewed from the front, and also contacts the left and right ends of the oscillating table 30. As a result, the amplitude of the oscillating body 11 can be easily restricted by the limiting stopper 20. Moreover, since a pair of limiting stoppers 20 are arranged on the left and right sides and contact both ends of the oscillating table 30 in the left and right directions, the vibration of the oscillating body 11 can be stabilized even more easily. Furthermore, since extensions 32 protrude outward from both ends of the table body 31 in the left-right direction, the left-right dimension of the oscillating table 30 can be easily increased, and the amplitude of the oscillating table 30 can be controlled with high precision by the limiting stopper 20.

[0065] Furthermore, since a spring is provided between the oscillating body 11 and the support table 10, the vibration of the oscillating body 11 can be easily stabilized. In particular, because the spring is a leaf spring, the spring constant can be easily increased, making it easier to stabilize the vibration of the oscillating body 11. Moreover, by arranging the leaf spring above and below the oscillating table 30, the vibration control of the oscillating body 11 becomes even easier.

[0066] Furthermore, the front-to-back dimensions of the lower support rod 14 and the upper support rod 34 are longer than the front-to-back dimensions of the anvil contact portion 54. Moreover, the lower support rod 14 and the upper support rod 34 extend symmetrically to the front and rear of the anvil contact portion 54. As a result, rattling and vibration in the front-to-back direction of the oscillating body 11 can be suppressed, and the oscillating body 11 can be stably oscillated in the left-to-right direction.

[0067] In this embodiment, a leaf spring is used as the spring, but a coil spring 80 may be used as shown in Figure 15. In the configuration shown in Figure 15, the coil spring 80 is provided on only one side, either left or right, but it may be provided on both sides. Also, the limiting stopper 20 is provided on only one side, either left or right. Thus, a pair of limiting stoppers 20 may be provided on both sides, or only on either the left or right side. Furthermore, although the limiting stopper 20 is provided on the opposite side in the left-right direction from the coil spring 80, it may be provided on the same side. Also, as shown in Figure 15, the limiting stopper 20 may abut against the upper surface of the extension portion 32.

[0068] <Comparison Test 1> We fabricated two types of anvils: a leaf spring seesaw type anvil 2, as shown in Figure 1, with a seesaw-type oscillating table 30 equipped with leaf springs (upper spring 70 and lower spring 71); and a coil spring seesaw type anvil 2, as shown in Figure 15, with a seesaw-type oscillating table 30 equipped with a coil spring 80. We also fabricated a sliding type anvil, which had a sliding table supported on a support table so as to be slidable in the left-right direction, and a coil spring placed between the sliding table and the support table. Vibration tests were performed on these three anvils 2.

[0069] In the leaf spring seesaw type anvil 2, the anvil contact portion 54 vibrated at the same frequency as the horn contact portion 6, and the phase difference between the horn contact portion 6 and the anvil contact portion 54 was approximately 150°, resulting in stable vibration of the anvil contact portion 54. When the left-right amplitude of the horn contact portion 6 was 25 μm in PP value, the left-right amplitude of the anvil contact portion 54 was approximately 9 to 13 μm in PP value, demonstrating that a large amplitude could be secured.

[0070] In the coil spring seesaw type anvil 2, the anvil contact portion 54 vibrated at the same frequency as the horn contact portion 6, similar to the leaf spring seesaw type anvil 2. The phase difference between the horn contact portion 6 and the anvil contact portion 54 was approximately 90 to 150°. Compared to the leaf spring seesaw type anvil 2, the phase difference between the horn contact portion 6 and the anvil contact portion 54 was slightly less stable. When the left-right amplitude of the horn contact portion 6 was 26 μm in PP value, the left-right amplitude of the anvil contact portion 54 was large, approximately 9 to 10 μm in PP value, which was comparable to the large amplitude achieved in the leaf spring seesaw type anvil 2.

[0071] In the sliding anvil 2, the anvil contact portion 54 vibrated at the same frequency as the horn contact portion 6, and the phase difference between the horn contact portion 6 and the anvil contact portion 54 was approximately 90°. However, when the lateral amplitude of the horn contact portion 6 was 30 μm in PP value, the lateral amplitude of the anvil contact portion 54 was small, approximately 2-3 μm in PP value, and the vibration of the anvil contact portion 54 was unstable.

[0072] Thus, a clear difference in vibration test results was observed between the seesaw-type anvil 2 and the slide-type anvil 2. This can be inferred as follows: In the case of the seesaw-type anvil 2, the rocking table 30 is inherently prone to tilting, making the structure of the rocking table 30 itself unstable. Therefore, the rocking table 30 is more susceptible to vibration in response to the vibration of the horn 1, resulting in a larger amplitude. On the other hand, in the case of the slide-type anvil 2, the slide table is highly stable, and the sliding direction of the slide table is perpendicular to the downward load from the horn contact portion 6. Therefore, even if the horn contact portion 6 vibrates in the left-right direction, the slide table is less likely to slide in that direction, resulting in a smaller amplitude.

[0073] <Comparison Test 2> Next, we compared a fixed type anvil 2 that does not swing with the coil spring seesaw type anvil 2 described above. Specifically, we performed workpiece joining tests using both the fixed type anvil 2 and the coil spring seesaw type anvil 2. The first workpiece 3 and the second workpiece 4 were made of the same material and thickness. For the workpiece samples, we used three types: A1050 (pure aluminum) with a thickness of 1 mm, A5052 (aluminum alloy) with a thickness of 10 mm, and LB3-H14 (aluminum alloy for lithium-ion battery cases) with a thickness of 1.1 mm.

[0074] In the coil spring seesaw type anvil 2, a sufficient bonding state was obtained for all three types of samples. For the A1050 sample, the tensile strength when the workpieces were pulled in a direction perpendicular to the bonding direction was 580-820N. Similarly, the tensile strength of the A5052 sample was 190-400N, and the tensile strength of the LB3-H14 sample was 230-480N. Thus, sufficient bonding strength was obtained.

[0075] On the other hand, in the case of fixed anvil 2, in the A1050 sample, only the peripheral portion of the sample was joined, while the majority of the rest was not joined. Also, in the A5052 and LB3-H14 samples, neither was joined. [Explanation of Symbols]

[0076] 1 horn 2 Anvils 2a center line 3. First Work 4. Second Work 5 Horn Tips 6. Horn contact area 7 Mounting Table 10. Support table (support) 11. Oscillator 12 mounting holes 13 Lower groove 14 Lower support rod 15 Lower support surface 15a Top 16 rotation axis 17 Lower facing surface 18 Bottom surface 19 Notched groove 20 Limit Stopper 20a top surface 30. Oscillating table (oscillating base) 31 Table body 32 Stretching section 33 Kamimizo 34 Upper support rod 35 Upper support surface 36 contacts 37 Upper facing surface 38 Screw recess 39. Regulatory aspects 40 Spring support surface 41 Notched recess 50 Mid-base 51 Anvil Body 52 Main part 53 Chip section 54 Anvil contact section 60 Side cover 70 Upper spring 70a Upper fixed end 70b Upper working end 71 Lower spring 71a Lower fixed end 71b Lower working end 72 Spring retainer 73 Pillar 80 Coil Springs

Claims

1. An ultrasonic bonding apparatus comprising a horn and an anvil for clamping multiple workpieces in a first direction, wherein the horn vibrates in a second direction perpendicular to the first direction, Anvil, Support and A oscillating body that contacts the workpiece and is supported by a support so as to be rotatable about a pivot axis along a third direction perpendicular to the first and second directions, and that vibrates at the same frequency as the horn but with a different phase, An ultrasonic bonding device equipped with the following features.

2. The horn has a horn contact portion that contacts the workpiece. The oscillating body has an anvil contact portion that contacts the workpiece. The ultrasonic bonding apparatus according to claim 1, wherein, when viewed in a third direction, the horn contact portion, the anvil contact portion, and the rotation axis are aligned in a straight line along the first direction.

3. The ultrasonic bonding apparatus according to claim 2, further comprising a limiting stopper that faces the oscillating body with a gap between them and the oscillating body when the amplitude of the oscillating body exceeds a certain level, thereby limiting the amplitude of the oscillating body.

4. The oscillating body has an end on the support side in the first direction and an oscillating base portion extending in the second direction. The ultrasonic bonding apparatus according to claim 3, wherein the limiting stopper is provided on the support and abuts in the first direction against the end of the oscillating base portion in the second direction.

5. The ultrasonic bonding apparatus according to claim 4, wherein the limiting stopper is provided on the support so as to be adjustable in a first direction.

6. The horn has a horn contact portion that contacts the workpiece. The oscillating body has an anvil contact portion that contacts the workpiece. The ultrasonic bonding apparatus according to claim 1, wherein the amplitude of the anvil contact portion in the second direction is smaller than the amplitude of the horn contact portion in the second direction.

7. The ultrasonic bonding apparatus according to claim 6, wherein the amplitude of the anvil contact portion in the second direction is 20% or more of the amplitude of the horn contact portion in the second direction.

8. The ultrasonic bonding apparatus according to claim 7, wherein the amplitude in the second direction of the anvil contact portion is 5 μm or more in P-P value.

9. An anvil for an ultrasonic bonding apparatus, which clamps multiple workpieces in the first direction together with a horn that vibrates in a second direction perpendicular to the first direction, Support and A oscillating body that contacts the workpiece and is supported by a support so as to be rotatable about a pivot axis along a third direction perpendicular to the first and second directions, and that vibrates at the same frequency as the horn but with a different phase, An anvil for an ultrasonic bonding device.

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