Ultrasonic welding device

Abstract

Provided is an ultrasonic welding device comprising: a base support having a recessed portion; an ultrasound stack provided on the base support; and an adjustment housing that surrounds the ultrasonic stack and is seated inside the recessed portion, wherein the base support and the adjustment housing are configured such that the distance therebetween can be adjusted from one side.

Description

ultrasonic welding device

[0001] The present invention relates to an ultrasonic welding device, and more particularly, to an ultrasonic welding device capable of easily and precisely adjusting the horizontality of a horn relative to an anvil.

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0019386, filed February 8, 2024, the entire disclosure of which is incorporated herein by reference.

[0003] Secondary batteries, unlike non-rechargeable primary batteries, are rechargeable and dischargeable. They are widely used in electronic devices such as mobile phones, laptops, and camcorders, as well as electric vehicles. In particular, lithium secondary batteries have a higher capacity than nickel-cadmium or nickel-hydrogen batteries and a higher energy density per unit weight, leading to a rapid increase in their use.

[0004] Various manufacturing methods are being proposed and applied to manufacture secondary batteries, but various efforts are being made to reduce the defect rate of products.

[0005] The technical problem to be achieved by the present invention is to provide an ultrasonic welding device capable of easily and precisely adjusting the horizontality of a horn with respect to an anvil.

[0006] The present invention provides an ultrasonic welding device comprising: a base having a concave portion; an ultrasonic stack provided on the base; and an adjustment unit housing that surrounds the ultrasonic stack and is seated within the concave portion, in order to achieve the above technical task, wherein the base and the adjustment unit housing are configured such that a gap between them can be adjusted from one side.

[0007] In some embodiments, the adjustment housing comprises a lower housing and an upper housing, and the lower housing and the upper housing can be configured to cooperate with each other to surround a side surface of the ultrasonic stack.

[0008] In some embodiments, the lower housing may include a lower surface corresponding to a concave surface of the recess of the base.

[0009] In some embodiments, the upper housing and the lower housing may be fastened by housing fastening bolts.

[0010] In some embodiments, the adjustment member housing can be configured to rotate about an axis of rotation by adjusting the gap between the base and the adjustment member housing.

[0011] In some embodiments, the rotational axis may be substantially parallel to the extension direction of the ultrasonic stack.

[0012] In some embodiments, the adjustment unit housing includes a through hole on each side with the ultrasonic stack therebetween, and the ultrasonic welding device may further include a first bolt that is fastened to the base by passing through the through hole provided in the adjustment unit housing on one side of the ultrasonic stack, and a second bolt that is fastened to the base by passing through the through hole provided in the adjustment unit housing on the other side of the ultrasonic stack.

[0013] In some embodiments, a first compression spring may be interposed between the head of the first bolt and the adjustment housing, and a second compression spring may be interposed between the head of the second bolt and the adjustment housing.

[0014] In some embodiments, the spring constant of the first compression spring and the spring constant of the second compression spring may be different from each other.

[0015] In some embodiments, the spring constant of the first compression spring may be greater than the spring constant of the second compression spring.

[0016] In some embodiments, the ultrasonic welding device may further include an adjustment bolt that can contact the adjustment member housing while penetrating the expectation.

[0017] In some embodiments, the adjusting bolt may be configured to be capable of moving in a direction that compresses the first compression spring by its own rotation.

[0018] Another aspect of the present invention provides an ultrasonic welding device comprising: an ultrasonic stack; an adjustment housing surrounding the ultrasonic stack and having a housing protrusion on one side; a base having a support protrusion corresponding to the one side of the adjustment housing and provided to at least partially support the adjustment housing; and an adjustment bolt configured to penetrate the support protrusion and contact the housing protrusion, wherein the adjustment bolt is configured to adjust a distance between the support protrusion and the housing protrusion.

[0019] In some embodiments, the adjustment member housing may be configured to rotate at a predetermined angle about the rotation axis by advancement of the adjustment bolt.

[0020] In some embodiments, the ultrasonic stack may include a vibration generator and a horn.

[0021] The ultrasonic welding device according to embodiments of the present invention can easily and precisely adjust the horizontality of the horn with respect to the anvil, thereby significantly improving the welding quality.

[0022] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0023] FIG. 1 is a perspective view of an ultrasonic welding device according to one embodiment of the present invention.

[0024] Figure 2 is an exploded perspective view showing the main parts of an ultrasonic welding device according to one embodiment of the present invention.

[0025] Fig. 3 is a side view of the ultrasonic welding device.

[0026] Figure 4 is an enlarged partial view of part A of Figure 3.

[0027] Fig. 5 is an exploded perspective view showing the main parts of an ultrasonic welding device according to another embodiment of the present invention.

[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. It is preferable to interpret that the embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art. Like numbers refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Therefore, the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0029] While terms like "first" and "second" may be used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, a first component could be referred to as a "second component," and vice versa, without departing from the scope of the present invention.

[0030] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the inventive concept. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the expressions "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, operations, components, parts, or combinations thereof.

[0031] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Furthermore, it is to be understood that commonly used terms, such as those defined in dictionaries, should be interpreted to have a meaning consistent with their meaning within the relevant technical context, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0032] In some embodiments, where implementations are otherwise feasible, specific process sequences may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the described order.

[0033] In the accompanying drawings, variations in the shapes depicted may be expected, for example, depending on manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to the specific shapes of the regions depicted herein, but should include, for example, changes in shapes resulting from the manufacturing process. All terms "and / or" used herein include each and every combination of one or more of the mentioned components. In addition, the term "substrate" used herein may mean the substrate itself, or a laminated structure including the substrate and a predetermined layer or film formed on the surface thereof. In addition, the "surface of the substrate" in this specification may mean the exposed surface of the substrate itself, or the outer surface of a predetermined layer or film formed on the substrate.

[0034]

[0035] (Example 1)

[0036] FIG. 1 is a perspective view of an ultrasonic welding device (100) according to one embodiment of the present invention.

[0037] Figure 2 is an exploded perspective view showing the main parts of an ultrasonic welding device (100) according to one embodiment of the present invention.

[0038] Referring to FIGS. 1 and 2, the ultrasonic welding device (100) may include a base (110) having a recess (114); an ultrasonic stack (190) provided on the base (110); and an adjustment housing (120) surrounding the ultrasonic stack (190) and seated within the recess (114).

[0039] The above ultrasonic stack (190) may include a vibration generating unit (130) and a horn (140). The vibration generating unit (130) may include a vibrator (131) that converts electrical energy into mechanical vibration energy and a booster (133) that reduces or amplifies the amplitude of the vibrator (131). The vibration energy of the booster (133) may be transmitted to the horn (140) and used to fuse a work piece.

[0040] The above ultrasonic welding device (100) can weld the workpiece by frictional heat by placing the workpiece between an anvil (180) and a horn (140) and then vibrating the horn (140) while applying pressure thereto.

[0041] The anvil (180) may include an anvil base (181). The upper surface of the anvil base (181) may extend generally horizontally. The anvil (180) may support a workpiece pressed by the horn (140) from the lower side. In some embodiments, the upper portion of the anvil (180) may be configured to be detachable from the anvil base (181).

[0042] The vertical distance between the anvil (180) and the horn (140) can be adjusted. That is, the vertical distance between the anvil (180) and the horn (140) can be adjusted by adjusting the relative distance between them. In some embodiments, the relative distance between the anvil (180) and the horn (140) can be adjusted by moving at least one of them in the vertical direction. To this end, at least one of the anvil (180) and the horn (140) can be configured to be able to rise and fall.

[0043] The horn (140) may be positioned on the upper side of the anvil (180). In some embodiments, the horn (140) may have a square plate shape, and the lower end of the horn (140) may extend in one direction (e.g., the X-axis direction). The workpiece may be pressed and welded between the lower end of the horn (140) and the anvil (180).

[0044] In some embodiments, at least one of the bottom surface of the horn (140) and the top surface of the anvil (180) may be provided with a protrusion that improves contact with the workpiece. In this case, marks corresponding to the protrusion may remain on the workpiece after welding is completed.

[0045] In order to ensure excellent welding quality, the upper surface of the anvil (180) and the lower surface of the horn (140) must be maintained parallel to each other. The ultrasonic welding device (100) according to embodiments of the present invention is configured to be able to adjust the horizontality of the lower surface of the horn (140) in response to the upper surface of the anvil (180). Here, the horizontality of the lower surface of the horn (140) may mean an absolute horizontality associated with an absolute reference (e.g., the direction of gravity), but may also mean a relative horizontality with respect to the upper surface of the anvil (180).

[0046] As described above, the vibration generating unit (130) may include a vibrator (131) and a booster (133). The vibrator (131) and the booster (133) may have a generally cylindrical shape. The vibrator (131), the booster (133), and the horn (140) may be sequentially arranged in a straight line in a predetermined direction (e.g., the Y-axis direction), and the ultrasonic stack (190) may extend along the predetermined direction. Furthermore, the vibrator (131), the booster (133), and the horn (140) may have a common central axis.

[0047] The above-described adjustment unit housing (120) may surround the ultrasonic stack (190). In some embodiments, the adjustment unit housing (120) may include an upper housing (122) and a lower housing (124) that are coupled to each other with the ultrasonic stack (190) therebetween. The upper housing (122) and the lower housing (124) may be configured to cooperate with each other to at least partially surround a side surface of the ultrasonic stack (190). In some embodiments, the adjustment unit housing (120) may be configured to surround a side surface of the vibration generating unit (130).

[0048] The above adjustment unit housing (120) may further include a fastening member (128) that fastens the upper housing (122) and the lower housing (124). In some embodiments, the fastening member (128) may be a housing fastening bolt. The upper housing (122) may have a through hole through which the housing fastening bolt may pass. The lower housing (124) may have a fastening hole corresponding to the through hole through which the housing fastening bolt may be fastened.

[0049] The above-described base (110) may have a concave portion (114) capable of partially accommodating the adjustment unit housing (120). In some embodiments, the concave portion (114) may have an arc-shaped cross-section. The lower portion of the adjustment unit housing (120) may have a shape suitable for being seated in the concave portion (114). That is, the lower surface (124b) of the adjustment unit housing (120) may have a shape corresponding to the concave surface of the concave portion (114). In some embodiments, the shape corresponding to the concave surface may be a complementary shape to the concave surface.

[0050] In some embodiments, the base (110) and the adjustment housing (120) may be configured to have an adjustable gap therebetween on one side. By adjusting the gap between the base (110) and the adjustment housing (120) on one side, the adjustment housing (120) can be rotated relative to the base (110). By rotating the adjustment housing (120) relative to the base (110), the horizontality of the horn (140) can be adjusted.

[0051] The rotation axis around which the adjustment unit housing (120) rotates may be substantially parallel to the extension direction of the ultrasonic stack (190). In some embodiments, the vibrator (131), the booster (133), and the horn (140) have a common central axis, and the rotation axis may coincide with the central axis.

[0052] The above-described adjustment unit housing (120) may have through holes (124h1, 124h2) on both sides with the ultrasonic stack (190) in between. Specifically, the adjustment unit housing (120) may have first through holes (124h1) through which first bolts (151) may pass on one side of the ultrasonic stack (190). In addition, the adjustment unit housing (120) may have second through holes (124h2) through which second bolts (153) may pass on the other side of the ultrasonic stack (190). The first bolts (151) may pass through the first through holes (124h1) and be fastened to the base (110). In addition, the second bolts (153) may pass through the second through holes (124h2) and be fastened to the base (110).

[0053] The first bolts (151) may pass through the first through-holes (124h1) but may not be screw-connected to the adjustment unit housing (120). In addition, the second bolts (153) may pass through the second through-holes (124h2) but may not be screw-connected to the adjustment unit housing (120). In this case, the adjustment unit housing (120) may move in the up-and-down direction (e.g., in the Z-axis direction) along the stems of the first bolts (151).

[0054] In FIGS. 1 and 2, the first through-holes (124h1) and the second through-holes (124h2) are illustrated as being provided in the lower housing (124), but the present invention is not limited thereto. In some embodiments, the through-holes may be provided in the upper housing (122).

[0055] Figure 3 is a side view of the ultrasonic welding device (100).

[0056] Referring to FIGS. 2 and 3, a first compression spring (151sp) may be provided between the head portion (H) of the first bolt (151) and the adjustment unit housing (120). In addition, a second compression spring (153sp) may be provided between the head portion (H) of the second bolt (153) and the adjustment unit housing (120).

[0057] The first compression spring (151sp) can apply a force in a vertical direction (e.g., in the Z-axis direction) between the head portion (H) of the first bolt (151) and the adjustment unit housing (120) to the adjustment unit housing (120). Since the first bolt (151) is fastened to the base (110), the head portion (H) of the first bolt (151) receives a force from the first compression spring (151sp), but does not move in the vertical direction by the force. Meanwhile, the adjustment unit housing (120) receives a force from the first compression spring (151sp) and can move by the force.

[0058] The second compression spring (153sp) can apply a force in a vertical direction (e.g., in the Z-axis direction) between the head portion (H) of the second bolt (153) and the adjustment unit housing (120) to the adjustment unit housing (120). Since the second bolt (153) is fastened to the base (110), the head portion (H) of the second bolt (153) receives a force from the second compression spring (153sp), but does not move in the vertical direction by the force. Meanwhile, the adjustment unit housing (120) receives a force from the second compression spring (153sp) and can move by the force.

[0059] In some embodiments, the spring constant of the first compression spring (151sp) may be the same as the spring constant of the second compression spring (153sp).

[0060] In some other embodiments, the spring constant of the first compression spring (151sp) may be different from the spring constant of the second compression spring (153sp). In some embodiments, the first compression spring (151sp) may have a larger spring constant than the second compression spring (153sp). Therefore, the force required for the first compression spring (151sp) to compress the same length is greater than the force required for the second compression spring (153sp). Since the spring constant of the first compression spring (151sp) is greater than that of the second compression spring (153sp), the adjustment unit housing (120) may receive a force in a counterclockwise direction (i.e., direction 2) with respect to the drawing illustrated in FIG. 3.

[0061] The ultrasonic welding device (100) may further include an adjustment bolt (160) that penetrates the base (110) and comes into contact with the adjustment unit housing (120). In some embodiments, the adjustment bolt (160) may come into contact with the lower surface of the housing protrusion (126) of the adjustment unit housing (120). In some embodiments, the base (110) has a base protrusion (116) corresponding to the housing protrusion (126), and the adjustment bolt (160) may penetrate the base protrusion (116) and come into contact with the housing protrusion (126).

[0062] Figure 4 is an enlarged partial view of part A of Figure 3.

[0063] Referring to FIGS. 3 and 4, the adjustment bolt (160) can be moved forward or backward in a vertical direction (e.g., in the Z-axis direction) by rotation. The adjustment bolt (160) can be configured to be able to move in a direction that compresses the first compression spring (151sp) by rotation in one direction. In addition, the adjustment bolt (160) can be configured to be able to move in a direction that relaxes the first compression spring (151sp) by rotation in the opposite direction to the above direction.

[0064] Specifically, when the adjustment bolt (160) is moved forward in the vertical direction by rotation (i.e., direction 1), in other words, when it rises in the +Z direction of FIG. 3, the housing protrusion (126) in contact with the adjustment bolt (160) receives an upward force, and the adjustment unit housing (120) rises upward. As a result, the gap (G) between the adjustment unit housing (120) and the base (110) increases, and the first compression spring (151sp) can be compressed. Since the housing protrusion (126) receives an upward force, the adjustment unit housing (120) can be rotated clockwise by a predetermined angle overall with respect to the rotation axis.

[0065] Conversely, when the above adjustment bolt (160) is retracted vertically by rotation (i.e., in direction 2), that is, lowered in the -Z direction of FIG. 3, the housing protrusion (126) is forced downward by the first compression spring (151sp), and the adjustment unit housing (120) is lowered downward. As a result, the gap (G) between the adjustment unit housing (120) and the base (110) is reduced, and the first compression spring (151sp) can be relaxed. Since the housing protrusion (126) is forced downward, the adjustment unit housing (120) can be rotated overall counterclockwise by a predetermined angle with respect to the rotation axis (CL).

[0066] Therefore, by adjusting the forward and backward movement of the adjustment bolt (160) in the vertical direction, the adjustment housing (120) can be rotated clockwise or counterclockwise by a predetermined angle. As a result, it is possible to adjust the horizontality of the horn (140).

[0067] The above adjustment bolt (160) may be screw-connected to the support nut portion (117) so that the above adjustment bolt (160) can be vertically advanced or retreated by rotation. The support nut portion (117) may be a part of the support (110). In FIG. 4, the support nut portion (117) is illustrated as being exposed to the outside, but the support nut portion (117) may be provided on the inner surface of the through hole of the support (110) through which the adjustment bolt (160) passes.

[0068]

[0069] (Example 2)

[0070] Fig. 5 is an exploded perspective view illustrating the main components of an ultrasonic welding device (100) according to another embodiment of the present invention. The embodiment illustrated in Fig. 5 is substantially identical to the embodiments illustrated in Figs. 1 to 3 except that it further includes a stopper (171, 173). Therefore, the following description will focus on these differences.

[0071] Referring to FIG. 5, a first stopper (171) may be provided close to the first bolts (151).

[0072] In some embodiments, the first stopper (171) may be coupled to the base (110) by penetrating the adjustment unit housing (120) on one side of the adjustment unit housing (120). In addition, the first stopper (171) may inhibit the adjustment unit housing (120) from being lifted upward. In FIG. 5, the first stopper (171) is illustrated as including one bolt and one nut, but the present invention is not limited thereto. The first stopper (171) may be composed of one bolt, or another configuration known in the art that functions as a stopper may be employed.

[0073] When performing welding with the above ultrasonic welding device (100), the horn (140) can apply a predetermined pressure to the workpiece. In reaction to the pressure, the horn (140) and the adjustment housing (120) surrounding it can receive an upward force, thereby allowing the adjustment housing (120) to be lifted from the base (110). The first stopper (171) can serve to limit the movement of the adjustment housing (120) so that the horn (140) and the adjustment housing (120) are not lifted from the base (110).

[0074] The above first stopper (171) can be provided to the adjustment unit housing (120) and the base (110) after securing the horizontal level of the horn (140).

[0075] In some embodiments, a second stopper (173) may be further provided in proximity to the second bolts (153).

[0076] The second stopper (173) may be coupled to the base (110) by penetrating the adjustment unit housing (120) from the other side of the adjustment unit housing (120). In addition, the second stopper (173) may suppress the adjustment unit housing (120) from being lifted upward. In FIG. 5, the second stopper (173) is illustrated as including one bolt and one nut, but the present invention is not limited thereto. The second stopper (173) may be composed of one bolt, or another configuration that functions as a stopper as is known in the art may be employed.

[0077] The second stopper (173) can perform the same function as the first stopper (171). That is, the second stopper (173) can serve to limit the movement of the adjustment unit housing (120) so that the horn (140) and the adjustment unit housing (120) are not lifted from the base (110).

[0078] The second stopper (173) can be provided to the adjustment unit housing (120) and the base (110) after securing the horizontal level of the horn (140).

[0079] The ultrasonic welding device (100) described above can easily and precisely adjust the horizontality of the horn with respect to the anvil, thereby greatly improving the welding quality.

[0080] While the embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, modifications to future embodiments of the present invention will not depart from the scope of the invention.

[0081] [Explanation of symbols]

[0082] 100: Ultrasonic welding device

[0083] 110: Expectations

[0084] 114: Concave

[0085] 116: Expected protrusion

[0086] 120: Adjustment Unit Housing

[0087] 122: Upper housing

[0088] 124: Lower housing

[0089] 124h1: First through hole

[0090] 124h2: Second through hole

[0091] 126: Housing protrusion

[0092] 130: Vibration generating unit

[0093] 131: Vibrator

[0094] 133: Booster

[0095] 140: Soul

[0096] 151: First Volt

[0097] 151sp: First compression spring

[0098] 153: Second Volt

[0099] 153sp: Second compression spring

[0100] 160: Adjusting bolt

[0101] 180: Anvil

[0102] 181: Anvil Base

[0103] 190: Ultrasonic stack

Claims

1. Expectation having a concave part; Ultrasonic stack provided above expectations; and A tuning housing surrounding the ultrasonic stack and seated within the recess; Including, An ultrasonic welding device in which the above expectation and the above adjustment unit housing are configured such that their gap can be adjusted from one side.

2. In paragraph 1, The above adjustment housing includes a lower housing and an upper housing, An ultrasonic welding device characterized in that the lower housing and the upper housing are configured to cooperate with each other to surround a side surface of the ultrasonic stack.

3. In paragraph 2, An ultrasonic welding device characterized in that the lower housing includes a lower surface corresponding to the concave surface of the concave portion of the above-mentioned base.

4. In paragraph 2, An ultrasonic welding device characterized in that the upper housing and the lower housing are fastened by a housing fastening bolt.

5. In paragraph 1, An ultrasonic welding device characterized in that the above adjustment unit housing is configured to rotate about a rotation axis by adjusting the gap between the above base and the above adjustment unit housing.

6. In paragraph 5, An ultrasonic welding device, characterized in that the rotation axis is substantially parallel to the extension direction of the ultrasonic stack.

7. In paragraph 1, The above adjustment unit housing includes through holes on both sides with the ultrasonic stack in between, An ultrasonic welding device characterized in that it further includes a first bolt that is fastened to the base by penetrating the through hole provided in the adjustment unit housing on one side of the ultrasonic stack, and a second bolt that is fastened to the base by penetrating the through hole provided in the adjustment unit housing on the other side of the ultrasonic stack.

8. In paragraph 7, An ultrasonic welding device characterized in that a first compression spring is interposed between the head of the first bolt and the adjustment unit housing, and a second compression spring is interposed between the head of the second bolt and the adjustment unit housing.

9. In paragraph 8, An ultrasonic welding device characterized in that the spring constant of the first compression spring and the spring constant of the second compression spring are different.

10. In paragraph 9, An ultrasonic welding device characterized in that the spring constant of the first compression spring is greater than the spring constant of the second compression spring.

11. In paragraph 8, An ultrasonic welding device characterized in that it further includes an adjustment bolt that can contact the adjustment unit housing while penetrating the above expectation.

12. In paragraph 11, An ultrasonic welding device characterized in that the above adjustment bolt is configured to be capable of moving in a direction that compresses the first compression spring by its own rotation.

13. Ultrasonic stack; A tuning housing surrounding the ultrasonic stack and having a housing protrusion on one side; A base having a projection corresponding to the one side of the adjustment unit housing and provided to at least partially support the adjustment unit housing; An adjusting bolt configured to penetrate the above-mentioned projection and contact the above-mentioned housing projection; Including, An ultrasonic welding device characterized in that the above adjustment bolt is configured to adjust the distance between the above expected protrusion and the above housing protrusion.

14. In paragraph 13, An ultrasonic welding device characterized in that the above adjustment unit housing is configured to rotate at a predetermined angle with respect to a rotation axis by the advancement of the above adjustment bolt.

15. In paragraph 13, An ultrasonic welding device characterized in that the ultrasonic stack includes a vibration generating unit and a horn.

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