JP3670387B2 - High viscosity fluid application equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-viscosity fluid coating apparatus for coating a substrate with a high-viscosity fluid such as an adhesive for fixing electronic components or cream solder.
[0002]
[Prior art]
When the syringe is lifted after a highly viscous adhesive or the like is applied to the substrate, a so-called stringing phenomenon occurs in the adhesive, causing problems such as adhesion of the adhesive extending in a thread form to the terminal. On the other hand, it has been experimentally clarified that the occurrence of the thread drawing phenomenon is eliminated by slowly raising the nozzle several millimeters (at a low speed) after applying the adhesive. Therefore, in order to increase the speed of the apparatus, it is required that the syringe be lowered and raised before and after the adhesive application with high accuracy.
[0003]
The present applicant has previously filed an application (Japanese Patent Application No. 8-31480) for an applicator that allows the syringe to be lowered and raised with high accuracy. The high-viscosity fluid application apparatus in this application is configured to cause a series of operations from descending to ascending to be performed through the cam follower in each of the forward rotation operation and the reverse rotation operation of the cam. That is, the vertex of the contour curve of the cam is set as the descending end position of the siridine, and the sirizine is made to perform a series of operations from descending to ascending before and after sandwiching the apex. Therefore, a series of operations of descending, applying, and ascending the lysine is performed by forward rotation of the cam that is less than one rotation, and a series of operations of descending, applying, and ascending is performed by the subsequent reverse operation.
[0004]
[Problems to be solved by the invention]
As described above, in the conventional coating apparatus, the cam performs forward rotation and reverse rotation that are less than one rotation, so that the cam follower relatively reciprocates with respect to the peripheral surface of the cam, leaving a part that does not partially rotate. Will do. For this reason, the lubricating oil (grease) between the cam and the cam follower is brought close to the part that does not roll, and the lubricating oil (oil film) is likely to be cut off, the lubricating oil replenishment cycle is shortened, and the cam mechanism (particularly, The problem is that the life of the cam follower and its bearing) is shortened. In particular, such a problem becomes apparent when the speed of an apparatus required in recent years is increased.
[0005]
The present invention provides a high-viscosity fluid coating apparatus capable of extending the lubrication oil replenishment cycle and extending the life of the cam mechanism in a structure in which the syringe is moved up and down by forward and reverse rotation of the cam. Its purpose is to do.
[0006]
[Means for Solving the Problems]
The high-viscosity fluid application apparatus according to claim 1 lowers and raises a syringe filled with the high-viscosity fluid, and discharges the high-viscosity fluid from a nozzle attached to the tip of the syringe at the lower end position. A cam follower configured to freely rotate in the forward and reverse directions, and a cam follower that engages with the cam and causes the syringe to perform a series of operations from descending to rising in each of the forward rotation operation and the reverse rotation operation of the cam. A drive source that rotates the cam, and a control unit that outputs a rotation signal to the drive source, causes the cam to alternately perform forward rotation operation and reverse rotation operation less than one rotation, and periodically rotates the cam at least once. , Provided.
[0007]
According to this configuration, the syringe performs a series of operations of lowering, discharging, and ascending in a normal rotation operation of the cam that is less than one rotation based on a rotation signal output from the control unit to the cam drive source, and continues to one rotation. Even if the reverse rotation is less than that, the syringe performs a series of operations of lowering, discharging, and raising. The cam repeats this forward / reverse rotation alternately. In this case, since the drive source periodically rotates the cam at least once by the rotation signal output from the control unit, the lubricating oil is attracted to the peripheral surface portion of the cam where the cam follower does not roll by the application operation of the high-viscosity fluid. Can be evenly distributed over the entire circumferential surface of the cam. Note that the period (periodic) for rotating the cam at least once takes into account the operation of the apparatus, for each substrate to which the high-viscosity fluid is applied, for each driving time or number of driving of the cam, for every operating day of the coating apparatus, etc. Every time, every start of work, etc. are preferable.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a highly viscous fluid coating apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. This coating apparatus applies an adhesive for bonding electronic components onto a substrate, and FIG. 1 is a side view thereof. As shown in the figure, the coating apparatus 1 includes a coating unit 2 that coats the adhesive A on the substrate B, and a unit lifting device 3 that lifts and lowers the coating unit 2.
[0009]
The unit lifting / lowering device 3 includes a base 11, a lifting / lowering motor 12 attached downward to the upper end of the base 11, and a ball screw 13 that engages the coating unit 2 and lifts / lowers it. The ball screw 13 is rotatably supported by a pair of bearing portions 14 a and 14 b extending from the base 11 at both upper and lower ends, and is connected to the lifting motor 12 via a coupling 15 at the upper end. A nut portion 41 of a mounting plate 31 of the coating unit 2 to be described later is screwed to the ball screw 13, and a guide receiving portion 42 of the mounting plate 31 is vertically arranged on a guide portion 16 formed on the lower portion of the base 11. It is slidably engaged. When the lifting motor 12 rotates, the ball screw 13 rotates, the mounting plate 31 guided by the guide portion 16 moves in the vertical direction, and the coating unit 2 moves up and down.
[0010]
A compressed air discharge valve 21 is attached to the upper side of the mounting plate 31, and a compressed air supply pipe 22 connected to a supply source such as a compressor (not shown) is connected to the inflow side of the discharge valve 21. ing. The discharge valve 21 is composed of an electromagnetic three-way valve or the like, and supplies compressed air to the coating unit 2 to discharge the adhesive A in the syringe 34.
[0011]
The coating unit 2 includes a mounting plate 31 attached to the unit lifting device 3, a bracket 32 whose rear surface is fixed to the mounting plate 31, a lifting shaft 33 supported by the bracket 32 so as to be movable up and down and rotatable, and a lifting shaft 33. The nozzle 34 which discharges the adhesive agent A directly is attached to the lower end of the syringe 34. A syringe lifting device 36 is attached to the bracket 32. That is, the syringe 34, strictly speaking, the syringe 34, the nozzle 35, and the lifting shaft 33 are lifted and lowered by the unit lifting device 3 as a whole of the coating unit 2, and are also lifted and lowered by the syringe lifting device 36.
[0012]
In this case, the unit elevating device 3 first lowers or raises the coating unit 2 so that the nozzle (syringe 34) 35 is located at the lower end position corresponding to the substrate thickness with respect to the substrate B. Next, the syringe lifting device 36 lowers the nozzle (syringe 34) 35 from this position to a position where the adhesive A is applied to the substrate B.
[0013]
The mounting plate 31 is formed with a nut portion 41 that is screwed into the ball screw 13 of the unit lifting device 3 at the middle portion, and a guide receiving portion 42 that is slidably engaged with the guide portion 16 of the unit lifting device 3 at the lower portion. Is formed. In addition, a joint forming portion 43 that connects the discharge valve 21 and the lifting shaft 33 is formed on the upper portion of the mounting plate 31.
[0014]
The elevating shaft 33 is intermittently formed with splines at required positions in the axial direction on the outer peripheral surface, and has a hollow shaft center portion, and an air passage 33a for compressed air is formed in the hollow portion. The upper end portion of the elevating shaft 33 is joined so as to be inserted into the joint forming portion 43 of the mounting plate 31, and the discharge pipe 23 of the discharge valve 21 is connected to the joint forming portion 43 from above. A joint groove 44 is formed in the joint forming portion 43 from the lower side, and the discharge pipe 23 of the discharge valve 21 communicates with the joint groove 44 from the upper side through the joint forming portion 43. A bush 45 and a shield ring 46 are inserted into the inner peripheral surface of the joining groove 44, and an upper end portion of the elevating shaft 33 is fitted inside the bush 45 and the shield ring 46. That is, the upper end portion of the elevating shaft 33 is in airtight contact with the shield ring 46 on its outer peripheral surface and is slidably and rotatably joined in the axial direction (vertical direction). Thereby, the mutual air passage 33a is airtightly communicated between the discharge valve 21 on the fixed side and the lifting shaft 33 on the movable side.
[0015]
A pulley 51 is mounted on the elevating shaft 33 located between the joint forming portion 43 and the upper bracket portion 32 a of the bracket 32. The pulley 51 is fixed to an upper nut member 52 that passes through the upper bracket portion 32a. The upper nut member 52 is rotatably supported by the upper bracket portion 32a and is engaged with the lifting shaft 33 by spline engagement. ing. That is, the elevating shaft 33 is engaged with the pulley 51 and the upper nut member 52 so as to be slidable in the axial direction while being rotated, and the pulley 51 and the upper nut member 52 move up and down with respect to the upper bracket portion 32a. Impossible and rotatable engagement. On the other hand, a timing belt (not shown) and a motor for running the timing belt are connected to the pulley 51, and the pulley 51 is moved in a state in which the elevating shaft 33 can be moved up and down as the timing belt runs. Reverse rotation. The syringe 34 and the nozzle 35 are rotated by forward / reverse rotation of the elevating shaft 33, and a pair of nozzle main bodies (described later) 35 a constituting the nozzle 35 is rotated about the axis of the nozzle 35 by an angle θ from the reference line.
[0016]
The syringe lifting device 36 includes a support frame 61 attached so as to pass between the upper bracket portion 32a and the lower bracket portion 32b of the bracket 32, a drive source 62 such as a motor incorporated in the support frame 61, and an output shaft of the drive source 62. A plate cam 64 fixed to 63 and a “T” -shaped rotation arm 65 incorporating a cam follower 66 that engages with the plate cam 64 are provided. The plate cam 64 and the cam follower 66 constitute a cam mechanism, and the plate cam 64 is rotated within a predetermined angle range by forward and reverse rotation of the drive source 62. Therefore, when the plate cam 64 rotates, the rotating arm 65 follows and rotates. A so-called eccentric eccentric cam or the like is used for the plate cam 64, and its displacement curve is formed to draw, for example, a sine curve (a cam curve such as a modified sine or a universal curve). The cam follower 66 is composed of a roller follower and is rotatably attached to one arm end of the rotating arm 65.
[0017]
A control unit S is connected to the drive source 62, and the drive source 62 is controlled by the control unit S, whereby forward and reverse rotation of the plate cam 64 and periodic rotation of the plate cam 64 described later are performed. That is, the drive source 62 and the control unit S constitute drive means for controlling and rotating the plate cam 64.
[0018]
The rotating arm 65 is pivotally supported at the lower part of the support frame 61, and a roller 67 is rotatably attached to the other one arm end. The roller 67 is in contact with the flange-like backing plate 53 fixed to the lifting shaft 33 from the lower side. On the other hand, a coil spring 55 is attached between the abutting plate 53 and the spacer 54 disposed below the upper nut member 52 so as to be wound around the elevating shaft 33. That is, the coil spring 55 receives the spacer 54 and the upper nut member 52 and urges the lifting shaft 33 and the roller 67 downward via the contact plate 53. Therefore, when the roller 67 rotates upward, the lifting shaft 33 is moved up against the coil spring 55, and when the roller 67 rotates downward, the lifting shaft 33 is moved down by the coil spring 55.
[0019]
A lower nut member 56 is disposed in the lower bracket portion 32b so as to penetrate therethrough. The lower nut member 56 is rotatably supported by the lower bracket portion 32 b and is spline-engaged with the lifting shaft 33. That is, the elevating shaft 33 engages with the lower nut member 56 so as to be slidable in the axial direction while being rotated, and the lower nut member 56 cannot move up and down with respect to the lower bracket portion 32b and is rotatable. Is engaged.
[0020]
The nozzle 35 includes a pair of nozzle main bodies 35a, a pair of stopper pins (only one shown) 35b, and a holding portion 35c that holds the nozzle main body 35a and the stopper pins 35b. It is attached to the lower end of. The pair of nozzle main bodies 35a are disposed at a 180 degree point symmetrical position with respect to the center of the holding portion 35c, and the pair of stopper pins 35b are shifted from the nozzle main body 35a by an angle of 90 degrees to the center of the holding portion 35c. Are arranged at 180 ° point symmetrical positions. In this case, the pair of nozzle main bodies 35a apply the adhesive A for one electronic component at two places simultaneously, and the stopper pins 35b are used when the adhesive A is applied to the substrate B. A discharge space for the adhesive A is formed between the tip of 35a and the substrate B.
[0021]
FIG. 2 shows the displacement curve P of the plate cam 64 and the drive waveform Q of the drive source 62 corresponding thereto. The plate cam 64 rotates about an apex of the contour curve, which is the lowest point of the displacement curve P, by 150 degrees in the circumferential direction in a total angle range of 300 degrees. That is, the position at an angle of 180 degrees is the descending end position of the lifting shaft (nozzle 35) 33, and the positions at the angles of 30 degrees and 330 degrees are the rising end position of the lifting shaft (nozzle 35) 33. Thus, when the drive source 62 is activated, the elevating shaft (nozzle 35) 33 descends from the ascending end position, eventually reaches the descending end position, and further rises from the descending end position to return to the original ascending end position. Stop.
[0022]
The displacement of the raising / lowering shaft (nozzle 35) 33 when moving up and down draws a sine (cosine) curve. . Since the adhesive A is applied by the nozzle 35 before and after the lowered end position, the ascending / descending speed of the nozzle 35 before and after the application of the adhesive A is extremely low. The illustrated displacement curve P represents one application operation of the adhesive A. In one application operation, the drive source 62 can stop even if the plate cam 64 reaches the lower end position. Instead, it rotates at a constant speed from start to stop (although it actually shifts during start and stop). Therefore, when the drive source 62 rotates in the forward direction, any one coating operation is performed, and when the driving source 62 rotates in the next direction, the subsequent one coating operation is performed. That is, the application operation is performed in each of the forward and reverse rotations of the drive source 62.
[0023]
On the other hand, the lifting stroke of the nozzle (elevating shaft 33) 35 by the plate cam 64 is adjusted by reducing the rotation angle of the plate cam 64 around the vertex. In this embodiment, when the angle range of 300 degrees between the angles of 30 degrees and 330 degrees is used, the maximum lifting stroke is, for example, the angle range of 220 degrees between the angles of 70 degrees and 290 degrees. When is used, the lifting stroke is shortened. As a result, the nozzle 35 can be raised to a position where the stringing that is different depending on the type of the adhesive A is reliably eliminated without changing the raising / lowering operation in the vicinity of the lowered end position. Thereby, the raising / lowering stroke can be shortened to the limit where stringing is eliminated, and the operation time of each coating operation can be shortened. That is, the tact time can be shortened and the overall speed of the apparatus can be achieved.
[0024]
As described above, the drive source 62 is connected to the controller S that controls the forward / reverse rotation of the plate cam 64 and the rotation angle thereof, and at the same time periodically rotates the plate cam 64 at least once (FIG. 1). reference). The control unit S appropriately outputs a signal for controlling forward / reverse rotation and rotation angle of the output shaft 63 and a signal for rotating the output shaft 63 a predetermined number of times, and the drive source 62 is controlled by these signals. Is done. Needless to say, the output timing of these signals emitted from the control unit S can be changed as appropriate according to the setting of the control unit S.
[0025]
As shown in FIG. 3, when the forward / reverse operation of the plate cam 64 continues for a long time by a series of application operations, a grease G pool is generated on the cam surface 64a at the reverse position of the cam follower 66 (the portion that does not roll). It becomes easy for the cam surface 64a to run out of grease. Therefore, in a state in which the cam follower 66 is returned to the home position H, control is performed at a predetermined cycle (every substrate, every cam driving time or the number of times of driving, every operation day of the coating apparatus, every closing time, every starting time, etc.). A rotation signal is output from the part S, and the plate cam 64 is rotated several times. As a result, the grease G collected on the cam surface 64 a is spread evenly over the entire circumferential surface of the cam 64 by the cam follower 66, and an appropriate amount of grease G spreads between the plate cam 64 and the cam follower 66. Therefore, the filling period of the grease G can be lengthened, and the life of the plate cam 64 and the cam follower 66 (particularly, the cam follower 66 and its bearing) can be lengthened.
[0026]
In this embodiment, the cam is constituted by a plate cam. However, as long as a cam such as a swash plate cam rotates, it may be a cam of another type.
[0027]
【The invention's effect】
As described above, according to the high-viscosity fluid coating apparatus of the present invention, the control unit outputs a rotation signal to the drive source, causes the cam to alternately perform forward rotation operation and reverse rotation operation of less than one rotation, and Since the cam is periodically rotated at least once, the lubrication oil replenishment cycle in the cam mechanism portion can be extended and the life of the cam mechanism can be extended without impairing the application performance of the highly viscous fluid. Therefore, it is possible to further accelerate the speeding up of the application work by the high-viscosity fluid application device .
[Brief description of the drawings]
FIG. 1 is a side view of a coating apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing a cam displacement curve and a drive waveform of a drive source in the syringe lifting device.
FIG. 3 is an enlarged view of a main part showing a relationship between a cam and a cam follower.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Coating device 2 Coating unit 3 Unit lifting device 33 Lifting shaft 34 Syringe 35 Nozzle 36 Syringe lifting device 62 Drive source 64 Plate cam (cam)
66 Cam Follower S Controller A Adhesive B Substrate G Grease

Claims (1)

In a high-viscosity fluid application device that lowers and raises a syringe filled with a high-viscosity fluid, and discharges the high-viscosity fluid from a nozzle attached to the tip of the syringe at the lower end position,
A cam configured to freely rotate forward and reverse,
A cam follower that engages the cam and causes the syringe to perform a series of operations from descending to ascending in each of the forward rotation operation and the reverse rotation operation of the cam;
A drive source for rotating the cam;
A controller for outputting a rotation signal to the drive source, causing the cam to alternately perform forward rotation operation and reverse rotation operation of less than one rotation, and periodically rotating the cam at least once. A highly viscous fluid coating apparatus.

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