JP2016107279A - Spring pressure type joining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve stable joining even when a pressure force is increased by stabilizing a pressure force applied to a joining head during joining of a joined article having a large crushing amount.SOLUTION: The spring pressure type joining device includes: a pair of upper and lower spring case half bodies 38 and 40 respectively held to be slidable independently in a base part 10 and having a maximum defined separating space; a repulsion force setting spring 36 contracted to be provided between the spring case half bodies 38 and 40; a repulsion force adjustment mechanism 58 for setting a repulsion force of the repulsion force setting spring 36; a lifting/pressurizing actuator 22 fixed to the base part 10 to pressurize the upper spring half body 38 downward; and an air regulator 28 for setting a pressure force applied by the air actuator 22. The pressure force of the air actuator 22 and the repulsion force of the repulsion force setting spring 36 are cooperatively operated in series to be added to a joining head 88.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a spring pressure type joining apparatus that pressurizes a joining head to an object to be joined via a spring, and joins the joining head while pressing the joining head into the article to be joined.

  2. Description of the Related Art Conventionally, a reflow soldering apparatus that joins electronic components and the like to a printed wiring board, a thermocompression bonding apparatus for plastic parts, and a welding joining apparatus such as spot welding are known. There is also a laser spot welding joining apparatus for welding with laser light.

  In this type of joining device, the pressure applied by an actuator such as an air cylinder is transmitted to the joining head via a spring, and a state where the spring is compressed by a predetermined amount (a state where the set pressure is applied) is detected by a microswitch or the like. Supply heating current and welding current to the head.

JP2009-195936 JP2007-173522 JP-A-7-32177 JP2011-110574

  In Patent Documents 1, 2, and 3, the actuator held on the base part is used to raise and lower the elevating part, while the pressing shaft (rod) held on the elevating part so as to be movable up and down is downwardly applied with a pressure setting spring ( What is pressurized with a coil spring is shown. Here, in Patent Documents 1 and 3, the actuators use the pedaling force of the foot pedal, and in Patent Document 2 the servo motor is used.

  Patent Document 4 discloses an actuator that uses an air cylinder as an actuator. That is, the coil spring (78) for setting the pressure force and the air cylinder (60) are sequentially arranged on the vertical line above the joining head (heater chip 126), and the joining head is formed by the piston shaft (62) of the air cylinder (64). Is pressed against the workpiece. In this state, the compression amount of the coil spring (78) is adjusted by the pressurizing force adjusting mechanism 108 to adjust the pressing force of the bonding head to perform bonding.

  In this case, in order to limit the descending amount of the piston shaft (62), the lower limit position (pressing stroke) of the air cylinder is restricted by a stopper (dial 70). If the lowering of the piston shaft (62) is not restricted, the air pressure of the air cylinder (64) is added to the compression force of the coil spring (78), and the pressure of the joining head (126) is applied during joining. Because it becomes unstable. For this reason, the air cylinder (64) raises and lowers the piston shaft (62) at the upper limit and lower limit positions, and is fixed by air pressure at the lower limit position so as not to affect the coil spring (78).

  According to what was shown in patent document 4, when the amount of crushing of the to-be-joined object at the time of joining is small, favorable joining is possible. However, the inventors of the present application have conducted experiments on various objects to be bonded, and as a result, have found that it is difficult to obtain good bonding results when the amount of collapse of the objects to be bonded is large. As a result of the analysis, it was found that the reason is that the fluctuation of the pressing force is greatly unstable. That is, when the joining head enters deeply into the article to be joined, the amount of extension of the coil spring increases, and the fluctuation of the spring force increases.

  Such joining with a large amount of deformation includes ultrasonic joining of an aluminum stranded wire to a copper plate, and thermal welding of a resin. In particular, in ultrasonic bonding, since it is necessary to vibrate while pressing the bonded portion with a strong pressure, the amount of crushed aluminum stranded wire increases. In the case of thermal welding of resin or the like, the head greatly enters the resin side as it melts. Thus, when the amount of entry of the joining head (pressure head) is large during joining, the applied pressure becomes unstable.

  The present invention has been made in view of such circumstances, and in particular, the pressure of the bonding head is stabilized during the bonding of the workpiece to be crushed, and stable bonding is possible even when the pressure is increased. It is an object of the present invention to provide a spring pressure type joining device.

  According to the present invention, this object is provided in the base part in a spring-pressing type joining apparatus that pressurizes the joining head, which is held up and down with respect to the base part, via the repulsive force setting spring. A pair of upper and lower spring case halves, each of which is vertically slidably held on a vertical slide rail and has a maximum separation interval, and a repulsive force setting spring that is compressed between these spring case halves; A repulsive force adjusting mechanism for setting the amount of compression of the repulsive force setting spring, an elevating / pressurizing air actuator which is fixed to the base portion and pressurizes the upper half of the spring case downward, and a pressure applied by the air actuator. And an air regulator for setting pressure, wherein the pressure applied by the air actuator and the repulsive force of the repulsive force setting spring are applied in series to the joining head in cooperation with each other. This is achieved by a spring-pressurized joining device.

  By adjusting the pressure (air pressure) of the air actuator with an air regulator, this pressure is always applied from the bonding head to the object to be bonded via the repulsive force setting spring. The repulsive force of the repulsive force setting spring can be adjusted by a repulsive force adjusting mechanism. Since the pressurizing force of the air actuator and the repulsive force of the spring for setting the repulsive force are applied in series to the joining head, the pressure at which the joining head pressurizes the object to be joined is set by the air pressure of the air actuator. At this time, the repulsive force of the repulsive force setting spring and the pressure of the air actuator are in an equilibrium state.

  In this state, the joining head is pressed against the object to be joined and starts joining. When the joining head enters the object to be joined, the repulsive force setting spring is instantly extended by the same amount as the amount of entry, and the air follows this. The actuator lowers the piston shaft. In other words, when the spring extends, the spring force of the spring decreases, while the pressure applied to the air actuator is always held constant by the air pressure held constant by the regulator. The spring is compressed by lowering, and the spring is returned to the prescribed length before the start of joining.

  For this reason, the pressure force of the joining head during joining can be kept constant and stabilized. In other words, it is difficult for the air regulator to improve the follow-up performance for restoring the applied pressure against the change in applied pressure, but the repulsive force setting spring has a high follow-up performance, so that the joined object is crushed. Sometimes it is possible to improve the followability. Accordingly, it is possible to obtain a stable joining result while maintaining a certain joining condition even when the joining head enters a workpiece to be crushed with a large amount of collapse.

The front view which shows the external appearance of one Example of this invention Same left side view Similarly, a front view showing a state where the base is omitted and the cover is removed. Similarly, the left side view of a partial cross section below

  The lifting / pressurizing actuator is connected to a vertical piston shaft and has an output shaft that moves back and forth up and down, the repulsive force setting spring is a coil spring, and the output shaft is a vertical common to the repulsive force setting spring. It can be arranged on a central axis line (claim 2). In this case, the pressure applied by the air actuator and the upward reaction force applied from the workpiece to the bonding head are located on the same straight line, and the offset amount from these central axes is 0, so the bonding pressure is particularly large. Suitable for construction.

  When the bonding head is an ultrasonic bonding head that pressurizes and bonds an object to be bonded via an ultrasonic bonding horn, the pressure applied during normal bonding increases, but according to the present invention, (Claim 3).

  The joining head includes a support arm having one end fixed to a lower end of a lower spring case half, an ultrasonic vibrator fixed to the other end of the support arm, and the spring case half from the ultrasonic vibrator. An ultrasonic vibration horn extending below the support arm, and a support rod fixed to the lower surface of the support arm and supporting the ultrasonic vibration horn in the vicinity of its vibration node. .

  While holding the actuator on the base, the pressure setting spring (coil spring) is housed between a pair of upper and lower spring case halves that are slidable up and down with respect to the base. If the lower end of the actuator output shaft and the joining head are fixed to the body, the lower half of the spring case itself can be used as a pressing shaft (pressing rod), and the number of parts can be reduced.

  The repulsive force adjusting mechanism used here has a structure in which a nut block that contacts the spring seat is moved up and down by a feed screw, and the rotation amount of the feed screw can be set by a pressure setting unit. For example, a horizontal setting shaft that meshes with the feed screw via a bevel gear can be provided, and one end of the setting shaft can face an opening provided in the half of the spring case to be rotatable from the outside.

  1-2, the code | symbol 10 is a base part, and integrates the horizontal baseplate 12 and the left-right paired support | pillar part 14 which stands up from the rear part. 2, 4, and 5 are fixed to the vertical front edges of both support columns 14, and an upper horizontal portion 18 that protrudes forward is fixed to the upper edge of the holding plate 16. Has been. A reinforcing material 20 is fixed to a joint corner portion between the holding plate 16 and the upper horizontal portion 18.

  An air cylinder 22 as an actuator is fixed to the upper portion of the holding plate 16. The piston shaft 24 that is the output shaft of the air cylinder 22 is made vertical, and the cylinder is fixed to the upper surface of the upper horizontal portion 18. The piston shaft 24 protrudes downward from an opening 26 (FIG. 4) provided in the upper horizontal portion 18. The central axis 24A of the piston shaft 24 is vertical, and passes through a joining position where a joining tip 98 described later contacts an object to be joined (workpiece, not shown).

  The piston shaft 24 is fixed to a piston (not shown) that slides up and down in the cylinder, and air is supplied to two upper and lower air chambers (air chamber, not shown) defined by the piston. The piston shaft 24 moves up and down. At this time, the air pressure supplied to each air chamber can be set constant by the regulator 28 (FIG. 3).

  That is, compressed air supplied from an air compression pump (not shown) is sent to the regulator 28 after the dust is removed by the air filter 30 (FIG. 3). The compressed air is maintained at a constant pressure set by the dial 28 </ b> A here, and then guided to the air chamber of the air cylinder 22 through the electromagnetic valve 32. Here, the electromagnetic valve 32 switches the air that is maintained at a constant pressure by the regulator 28 to the upper or lower air chamber of the air cylinder 22 and is operated by a control circuit (not shown). In FIG. 3, the alternate long and short dash line indicates this air flow. The air pressure set by the regulator 28 is detected by a sensor (not shown) and displayed on the display pressure meter 34 (FIGS. 1, 2, and 4).

  Below the air cylinder 22, a coil spring 36, which is a repulsive force setting spring, is disposed coaxially with the central axis 22A. Reference numerals 38 and 40 denote a pair of upper and lower spring cases that accommodate the coil spring 36. These spring case halves 38 and 40 are held on the front surface of the holding portion 16 so as to be movable up and down. That is, the slide blocks 38A and 40A fixed to the rear surfaces of the spring case halves 38 and 40 are held by the slide rail 42 fixed to the holding portion 16 so as to be movable up and down.

  In the lower spring case half 40, a housing chamber for the coil spring 36 is formed coaxially with the central axis 22A, and a lower spring seat 44 is fixed to the inner bottom thereof. An upper spring seat 46 opposite to the lower spring seat 44 is held movably up and down at the lower portion of the upper spring case 38, and a coil spring 36 is loaded between the upper and lower spring seats 44 and 46.

  The lower surface of the nut block 48 abuts on the upper surface of the upper spring seat 46. Here, the nut block 48 can be moved up and down while its rotation is restricted in the accommodation chamber formed in the upper spring case half 38 coaxially with the central axis 22A. That is, on the outer periphery of the nut block 48, a protrusion 52 is provided in the upper spring case half 38 that is engaged with the vertically long window 50 (FIGS. 1, 3, and 4). Rotation is restricted upon hitting. The vertical dimension of the window 50 is longer than the protrusion 52, and the nut block 48 can be moved up and down.

  A feed screw 54 is screwed into the nut block 48 from above. The feed screw 54 rotates while its vertical movement is restricted by a thrust bearing 56 attached to the upper spring case half 38. A repulsive force adjusting mechanism 58 is disposed near the upper end of the feed screw 54.

  The repulsive force adjusting mechanism 58 includes a horizontal setting shaft 60 that horizontally traverses above the feed screw 54, and a miter gear 62 that is a bevel gear fixed to the feed screw 54 and the horizontal setting shaft 60. A hexagon socket head 64 provided at one end of the horizontal setting shaft 60 protrudes from a circular opening provided in the front of the upper spring case half 38, and this head 64 is located inside a long window 76 provided in a cover 72 described later. The feed screw 54 is rotated by rotating with an Allen key driver (hexagon driver) from the upper outer side, and the nut block 48 can be moved up and down. As a result, the upper spring seat 46 can be moved up and down to adjust the amount of compression of the coil spring 36, that is, the spring force.

  The protrusion 52 of the nut block 48 and the window 50 are graduated so that the repulsive force of the coil spring 36 can be confirmed by the position of the nut block 48.

  In FIG. 3, 66 and 66 are hook-shaped stoppers fixed to the lower part of the upper spring case half 38 and formed on the left and right side surfaces of the lower spring case half 40 when the upper and lower spring case halves 38 and 40 are separated from each other. A gap A is formed between the spring case halves 38 and 40 by engaging with the step portions 68 and 68. On the front side of the upper and lower spring case halves 38, 40, a position detector 70 is mounted which is composed of an optical sensor that detects a relative position change between them, that is, a change in the gap A.

  This position detector 70 has a light shielding plate fixed to the lower spring case half 40 inserted between the light sensor and the light receiving sensor fixed to the upper spring case half 38 to thereby form both spring case halves 38, Forty intervals A can be detected.

  As described above, the pressure device portion of the joining device configured on the holding plate 16 is covered with the covers 72 and 74. That is, the front and left and right side surfaces of the holding plate 16 are covered with the cover 72, and the front and left and right side surfaces of the air cylinder 22 are covered with the cover 74. Here, from the front surface of the lower cover 72, the dial 28A of the regulator 28 projects to the front surface, and the operator can rotate the dial 28A to set the air pressure. This air pressure can be confirmed by an air pressure meter 34 attached to the front surface of the upper cover 74.

  Further, as shown in FIG. 1, a long window 76 is formed on the front surface of the lower cover 72, where the projection 52 is near the center, and the head 64 of the horizontal setting shaft 60, which is a hexagon socket bolt, is near the upper edge. Respectively. Therefore, the nut block 48 can be moved up and down from the elongated hole 76 by an Allen key driver, and the repulsive force of the coil spring 36 can be visually confirmed from the position of the nut block 48. The lower cover 72 is formed with a small window 78 for visually confirming the position detector 70 from the outside.

  Therefore, if the repulsive force of the coil spring 36 is set by the horizontal setting shaft 60 and the object to be joined is sandwiched between the anvil 100 and the joining tip 98 described later, the air pressure determined by the dial 28A of the regulator 28 is increased. The force with which the cylinder (actuator) 22 presses the upper spring case half 38 downward increases. When the pressing force of the air cylinder 22 becomes larger than the repulsive force of the coil spring 36, the coil spring 36 starts to be compressed, and the gap A (FIG. 3) between the upper and lower spring case halves 38 and 40 decreases. At this time, since the repulsive force increases due to the compression of the coil spring 36, it is balanced with the increased applied pressure of the air cylinder 22. The equilibrium position at this time, that is, the changed gap A can be confirmed from the long window 78.

  An ultrasonic bonding head 80 is fixed to the lower end surface of the lower spring case half 38. The ultrasonic bonding head 80 includes a support arm 82 bolted to the lower surface of the spring case half 38 and extending horizontally rearward, an ultrasonic transducer 84 fixed below the rear end, and the ultrasonic vibration. A horn 86 projecting forward from the child 84 and reaching the central axis 24A, and projecting downward from the lower surface of the support arm 82, the horn 86 is positioned at a position of about 1/4 wavelength of the ultrasonic vibration from the tip (vibration tip) position ( And a fulcrum bar 88 that supports (presses) the horn 86 from above in the vicinity of the vibration node. The horn 86 expands the vibration amplitude of the vibrator 84. The vibrator 84 generates vibration in the front-rear direction (vibration in the direction parallel to the center line 80A of the joining head 80 shown in FIG. 2, longitudinal vibration), and vibrates the horn 86. In addition, it includes one having a cone 86A for transmitting this vibration output from the vibrator 84 to the horn 86.

  The ultrasonic transducer 84 is a cylindrical case containing the ultrasonic transducer, and vibrates the horn 84 protruding from one end in the longitudinal direction. In this cylindrical case, a flange 90 on the mounting surface side of the horn 86 is sandwiched between two sandwiching plates 92, 94 from the front and back, and one of the two is fixed to the lower surface of the rear edge of the support arm 82 (FIG. 4). Here, in the horn 86, the length from the vibrator 84 to the fulcrum bar 88 is about ½ of the vibration wavelength, and the length from the fulcrum bar 88 to the joining position of the tip is about ¼ wavelength. ing. Therefore, the amplitude of the vibration waveform is maximized at the joining position.

  The holding plate 92 has a substantially U-shaped outer periphery so that the upper edge is horizontal and can be fixed to the support arm 82, and a circular opening through which the cylindrical case of the vibrator 84 passes is formed. It is a ring shape (annular) in which an opening is formed. Here, a pair of left and right substantially triangular triangular reinforcing plates 96 are fixed in the sandwiching angle between the support arm 82 and the sandwiching plate 92 in order to strengthen the coupling between them. The tip of the horn 86 has a quadrangular cross section, and a bonding tip 98 is fixed to each surface. Each joining tip 98 makes it possible to extend the use period of the horn 86 by rotating and changing the mounting position of the horn 86 around the central axis 80A when worn. In FIGS. 1 and 2, reference numeral 100 denotes an anvil (anvil), which is fixed to the base 10 so as to face the lower side of the joining tip 98, and an object to be joined (not shown) is the anvil 100 and the joining tip 98. It is sandwiched between and joined.

  Next, the operation of this embodiment will be described. First, the workpiece (workpiece) is positioned between the joining tip 98 and the anvil 100. In order to set the applied pressure corresponding to the object to be joined, the compression pressure (pre-pressure) of the coil spring 36 of the upper spring case half 38 is set by the repulsive force adjusting mechanism 58. That is, the setting is made by rotating the head 64 of the horizontal setting shaft 60 by means of an Allen key driver.

  By turning on an operation start switch 102 (FIGS. 1 and 2) provided on the front surface of the base unit 10, supply of air pressure adjusted by the regulator 28 to the air chamber above the air cylinder 22 is started. Then, the piston shaft 24 starts to descend, and the lower spring case half 40 coupled to the upper spring case half 38 by the stopper 66 is lowered integrally. And the joining chip | tip 98 contacts a to-be-joined object.

  When the air pressure is increased by the operation of the regulator 28, the lowering of the lower spring case half 40 is restricted by the object to be joined, while the upper spring case half 38 is released from the stopper 66 and lowered. When the pressing force by the air cylinder 22 is further increased, only the upper spring case half 80 is lowered while compressing the coil spring 36. When the position detector 70 detects that the descending amount becomes a constant set amount, a control circuit (not shown) supplies a driving current having a predetermined frequency to the vibrator 84 and vibrates the bonding chip 98.

  Since the pressing force of the lower spring case half 40 is applied to the bonding tip 98 via the fulcrum rod 88, the oxide film on the surface of the bonded portion is removed by vibration, and then two bonding surfaces are bonded. Bonded according to the characteristics of the materials. Diffusion bonding is possible when dissimilar metals such as aluminum strands and copper plates are bonded. In the case of resin bonding, fusion bonding is possible by melting the resin by frictional heat.

  In the case of a material with a large amount of crushing such as an aluminum stranded wire or a resin, the joining tip greatly enters the material at the time of joining. According to this embodiment, at this time, the coil spring 36 first extends for a moment and the restoring force (repulsive force) reduces the pressing force of the joining tip, but at the same time, a constant air pressure is supplied to the air cylinder 22. By supplying the air pressure, the air cylinder 22 pressurizes the coil spring 36 that has already been extended, and returns the compression amount of the coil spring 36 to the state before the start of joining. For this reason, it is possible to reduce the fluctuation of the applied pressure during the joining and to join at a stable pressure.

  That is, at the time of joining of the joining tip at the time of joining, first, the coil spring 36 having good responsiveness to the change in length is dealt with, and then the pressurizing force of the air cylinder 22 which is less responsive than the coil spring 36 is increased to stabilize the set pressing force It is something to be made.

  The control circuit monitors changes in pressure, drive current, and the like during bonding, and ends the bonding in a state that satisfies a predetermined condition. At this time, the control circuit raises the piston shaft 24 by switching the electromagnetic valve 32 and supplying air pressure to the air chamber below the air cylinder 22. Then, the upper spring case half 40 is pushed up by the coil spring 36 and the rise is restricted by the stopper 66. Further, when the piston shaft 24 of the air cylinder 22 rises, the joining tip 98 moves away from the joined portion, and the joining operation is finished.

10 Base 22 Air cylinder (actuator)
24 Piston shaft 22A Center axis 36 Coil spring (Repulsive force setting spring)
38 Upper spring case half 40 Lower spring case half 44, 46 Spring seat 48 Nut block 54 Feed screw 58 Repulsive force adjustment mechanism 60 Horizontal adjustment shaft (hexagon socket head cap screw)
64 Hexagon socket head bolt 80 Ultrasonic bonding head 82 Support arm 84 Ultrasonic transducer 86 Horn 88 Support rod 98 Bonding tip

Claims (4)

In a spring pressurizing type joining apparatus that pressurizes a joining head held so as to be movable up and down with respect to a base part downward through a spring for setting a repulsive force.
A pair of upper and lower spring case halves, each of which is held to be vertically slidable independently on a vertical slide rail provided on the base, and has a maximum separation interval;
A repulsive force setting spring that is compacted between the spring case halves;
A repulsive force adjusting mechanism for setting a compression amount of the repulsive force setting spring;
Elevating / lowering the upper and lower spring case halves fixed to the base and pressurizing downward
An air actuator for pressurization;
An air regulator for setting the pressure applied by the air actuator;
And a pressure applying force of the air actuator and a repulsive force of the repulsive force setting spring are applied in series to the joining head in cooperation with each other.   The lifting / pressurizing actuator has an output shaft that moves vertically back and forth, the repulsive force setting spring is a coil spring, and the output shaft is disposed on a central axis common to the repulsive force setting spring. The spring pressure type joining device according to claim 1.   2. The spring pressure bonding apparatus according to claim 1, wherein the bonding head is an ultrasonic bonding head that pressurizes and bonds an object to be bonded via an ultrasonic bonding horn.   The joining head includes a support arm having one end fixed to a lower end of a lower spring case half, an ultrasonic vibrator fixed to the other end of the support arm, and the spring case half from the ultrasonic vibrator. The spring pressure type bonding apparatus according to claim 1, further comprising: an ultrasonic vibration horn extending below the support arm; and a support rod fixed to the lower surface of the support arm and supporting the ultrasonic vibration horn in the vicinity of the vibration node.

Images