JP2011245566A - Chuck device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost by simplifying a structure of the whole device.SOLUTION: The chuck device 1 has forceps 20 capable of grasping a workpiece W at the front end thereof, an arm 30 contacting with the base end side of the forceps 20. a direct move type stepping motor 40 displacing the position of the arm 30 to the forceps 20 for making the forceps 20 openable by an elastic deformation, and a controller 50 having functions for decelerating the closing speed of the forceps 20 directly before grasping the workpiece, adjusting the closing distance of the closing state of the forceps 20, or accelerating the opening speed of the forceps when opening the workpiece.

Description

  The present invention relates to a chuck device that mechanically grips a workpiece or the like.

Chuck devices are widely used in machine tools, component conveying devices, and the like. When hydraulic pressure is used as the drive source of the apparatus, the apparatus itself becomes large, and therefore the work gripping portion is generally driven by an electric motor. One example is disclosed in Patent Document 1.

JP 2004-345019 A

However, in the case of the above conventional example, since the workpiece gripping member is opened and closed using a motor and a cam mechanism or the like, the entire apparatus becomes complicated, the assembly work becomes complicated, and it is difficult to reduce the cost. In addition, when it is necessary to perform high-speed driving or to control the opening / closing speed, it has been pointed out that the cam mechanism is complicated, so if it is designed in consideration of durability, it becomes more expensive. .

The present invention has been created under the above-described background, and an object of the present invention is to provide a chuck device capable of simplifying the structure of the entire apparatus.

  The chuck device according to the present invention includes a tweezers portion that can grip a workpiece on the distal end side, an arm portion that contacts the proximal end side of the tweezers portion, and an arm portion that can be opened and closed by elastic deformation. And a control unit that controls driving of the drive unit so that the tweezers can be opened and closed by elastic deformation.

  In the case of the above-described invention, when the drive of the drive unit is controlled by the control unit, and the arm unit is displaced with respect to the tweezers accordingly, the tweezers unit is elastically deformed and opened and closed by the contact of the arm unit. The overall structure of the device is simple and the number of parts is small, making assembly work easier. Therefore, it is possible to achieve a significant cost reduction compared to the conventional case.

  As for the example of the tweezers, a fulcrum portion provided on the rear end side and a pair of base end sides which are bifurcated members connected to the fulcrum portion and whose distal end side is provided obliquely outwardly with respect to the base axis direction A pair of distal end side portions, each of which is connected to the distal ends of the pair of proximal end side portions and the distal end side is provided in an obliquely inward direction with respect to the base axis direction, and the distal ends of the pair of distal end side portions. Have a pair of claw portions provided so as to face each other. As for the example of the arm part, a main body part connected to the output side of the driving part, a pair of arms respectively disposed in parallel to the front end side of the main body part around the base axis direction, and a front end side of the pair of arms And a pair of roller portions that respectively come into contact with a pair of proximal end side portions of the tweezers portion.

  The apparatus may further include a pressure sensor that detects pressure acting on the tweezers. As the control unit in this case, a control unit having a function of controlling at least the closing distance and / or the closing speed of the tweezers based on the detection result of the pressure sensor is used. For example, at the time of gripping a workpiece, the closing distance of the tweezers is obtained based on the detection result of the pressure sensor, and when the closing distance shows a predetermined value immediately before gripping the workpiece, the closing speed of the tweezers is reduced. Further, when the work is released, the open distance of the tweezers is obtained based on the detection result of the pressure sensor, and when the open distance shows a predetermined value immediately after the work is released, the opening speed of the tweezers is accelerated.

  In the case of the above invention, by properly controlling the opening / closing speed of the tweezers, the workpiece can be reliably gripped, the impact when gripping the workpiece is alleviated, or part of it when the workpiece is opened Can be scattered or misaligned. Furthermore, it becomes possible to measure the dimensions of the workpiece by a pressure-sensitive sensor when gripping the workpiece. In these respects, the device can be driven at high speed and the performance can be improved.

  The apparatus may further include a setting unit capable of setting and inputting at least a closing distance and / or a closing speed of the tweezers. As the control unit in this case, a control unit having a function of controlling the closing distance and / or closing speed of the tweezers according to the setting input of the setting unit is used.

  According to the above invention, the closing distance and / or closing speed of the tweezers when gripping the workpiece becomes appropriate according to the size, material, shape, etc. of the workpiece, and the gripping force and the like are appropriately adjusted to the workpiece. In addition, it is possible to appropriately adjust the speed from touching the workpiece to grasping it, thereby increasing the tact time and reducing the impact when gripping the workpiece. In these respects, high performance can be achieved.

  As the control unit, it is preferable to use a control unit having a function of controlling the driving of the driving unit so that the gripping force of the tweezers is increased when the workpiece is conveyed.

  In the case of the above invention, since the gripping force is increased when the workpiece is conveyed, the workpiece does not fall off from the tweezers during conveyance, and in this respect, it is possible to achieve higher speed driving and higher performance. .

  As an example of the pressure-sensitive sensor, there is a configuration including an elastic body portion sandwiched between tweezers and a detection unit that detects a force acting when the tweezers are opened and closed.

  According to the above invention, since the pressure sensitive sensor has a very simple configuration, there is an advantage in reducing the cost of the apparatus.

  As an example of the drive unit, there is a direct-acting stepping motor.

In the case of the above invention, since the stationary holding force of the stepping motor is large, the gripping of the workpiece is maintained by the tweezers only by stopping the driving of the motor. In addition, since no special motion conversion mechanism is required, the structure of the entire apparatus is simplified, and further cost reduction can be achieved.

It is a disassembled perspective view of the chuck device concerning an embodiment of the invention. It is a perspective view which shows the tweezers of the same apparatus, (a) is a figure which shows an open state, (b) is a figure which shows a closed state. It is a disassembled perspective view of the pressure sensor of the same apparatus. It is a typical side view for demonstrating operation | movement of the direct-acting stepping motor and arm part of the apparatus, (a) is a figure which shows an open state, (b) is a figure which shows a closed state. It is a block diagram which shows the electric constitution of the apparatus. It is a graph which shows the time change of the opening / closing distance of the tweezers when holding / releasing the workpiece of the apparatus.

  Hereinafter, a chuck device according to an embodiment of the present invention will be described with reference to FIGS. It should be noted that those for which the correspondence between the invention-specifying matters described in the claims and the components of the apparatus is unknown are shown together in the description of reference numerals described later.

  The chuck device 1 exemplified here is connected to a movable portion of a pick-and-place device (not shown) that transports the workpiece W (see FIG. 4) to another place, and grips / releases the workpiece W. It has a function. FIG. 4A shows the workpiece open state, and FIG. 4B shows the workpiece gripping state. In FIG. 1, 10 is a housing, 20 is tweezers, 30 is an arm portion, 40 is a direct-acting stepping motor, 50 in FIG. 5 is a controller, 51 is a driver, 52 is a setting unit, 71 is an origin sensor, and 72 is a sensor. It is a pressure sensor. The chuck device 1 is constituted by these parts. The power supply connected to the controller 50 and the driver 51 is not shown.

  As shown in FIG. 1, the housing 10 is a metal rectangular tubular body, and an arm portion 30 and tweezers 20 are provided therein. A motor housing 11 for mounting the direct acting stepping motor 40 is provided on the upper open surface of the housing 10. An origin sensor 71 is provided in the motor housing 11. A cylindrical portion 101 for attaching the tweezers 20 is provided on the inner side surface of the housing 10. A cover 12 is attached to the front open surface of the housing 10. The tip portion of the tweezers 20 is exposed from the lower open surface of the housing 10.

  The origin sensor 71 is a sensor that detects the opening of the workpiece. In the present embodiment, a micro switch is used, and whether or not a part of the arm portion 30 (the upper surface of the L angle portion 34 described later) is in contact with or close to the origin sensor 71. And the detection signal is output to the controller 50. When the arm unit 30 moves from the position shown in FIG. 4B to the position shown in FIG. 4A, the detection signal of the origin sensor 71 becomes active. However, the origin sensor 71 is not shown in FIG.

  The tweezers 20 are metal elastic plate-like members that can grip the workpiece W on the tip side, and are fixed inside the housing 10 in a hollow support form. Specifically, as shown in FIG. 2, a cylindrical tweezer pipe 21 provided on the rear end side in a direction perpendicular to the base axis direction A, and a bifurcated member connected to the tweezer pipe 21, and the tip side is The base end side portions 22a and 22b provided in the obliquely outward direction with respect to the base axis direction A and the distal ends of the base end side portions 22a and 22b are connected to the base end direction 22A and 22b. The front end side portions 23a and 23b are respectively provided toward the front end, and the claw portions 24a and 24b are provided so as to be connected to the front ends of the front end side portions 23a and 23b and to face each other. A screw 102 shown in FIG. 1 is inserted into the tweezer pipe 21. The tweezers 20 is fixed to the cylindrical portion 101 of the housing 10 by the screws 102. A pressure sensitive sensor 72 is attached to the tweezers 20.

  The arm portion 30 is a metal cross-recessed concave body whose front end side can be brought into contact with the proximal end side of the tweezers 20 and is guided by the surfaces of the proximal end side portions 22a and 22b of the tweezers 20 as shown in FIG. From the upper position shown in FIG. 4 to the lower position shown in FIG. Specifically, as shown in FIG. 1, a main body 31 connected to the tip of the screw shaft 41 of the linear stepping motor 40 and a main body 31 extending in parallel with the axial direction A are provided. Arm 32, 33, L angle portion 34 provided on the outer surface of arm 32, roller portion 35 a provided on the distal end side of arms 32, 33 and abutting on proximal end side portions 22 a, 22 b of tweezers 20, 35b.

  When the arm portion 30 is moving from the lower position shown in FIG. 4B to the upper position shown in FIG. 4A, the rollers 35a and 35b are moved to the base ends of the tweezers 20 as shown in FIG. The surfaces of the side portions 22a and 22b are moved in the direction indicated by the arrows. Along with this, the tweezers 20 are opened by the elastic force of the tweezers 20. On the other hand, when the arm portion 30 moves from the upper position shown in FIG. 4A to the lower position shown in FIG. 4B, the rollers 35a and 35b are moved to the proximal end side portion of the tweezers 20 as shown in FIG. The surfaces of 22a and 22b are moved in the direction of the arrow shown in the figure. Accordingly, the tweezers 20 are closed against the elastic force of the tweezers 20 by the pressing force of the arm portion 30.

  The pressure sensor 72 detects the pressure acting on the proximal end side portions 22 a and 22 b of the tweezers 20 and outputs this detection signal to the controller 50. Based on the detection result of the pressure sensor 72, the controller 50 not only measures the opening / closing distance between the claws 24a and 24b of the tweezers 20, but also the work W through the pattern of changes in pressure acting on the tweezers 20. Whether or not is gripped / released can be measured.

  Specifically, the pressure-sensitive sensor 72 is rubber or the like formed in a substantially triangular shape as shown in FIG. 3 and is attached by being sandwiched between the base end side portions 22a and 22b of the tweezers 20. And a detection unit 722 that is fixed to the slit portion 7211 formed in the elastic material 721 and detects a pressure acting on the tweezers 20 when the workpiece is gripped or released. About the detection part 722, the charcoal paper 7221 formed by winding in the shape of a rectangular tube, the conductors 7222 and 7223 which are copper plates inserted into the charcoal paper 7221, and the insulation sandwiched between the conductors 7222 and 7223 It has an insulator 7224 made of paper and signal output wires 7225 and 7226 electrically connected to the conductors 7222 and 7223, and converts the pressure acting through the elastic material 721 into a resistance value and outputs it. ing.

  The linear stepping motor 40 is a linear step motor for opening and closing the tweezers 20 by elastic deformation as shown in FIG. 1, and a mechanism for converting the rotational motion of the shaft of the stepping motor and the motor into linear motion. The screw shaft 41 which is the output side of the mechanism can be moved in the base axis direction A step by step. The reason why the stepping motor is used as the drive source for opening and closing the tweezers 20 is mainly because of the large static holding force, and the reason why the linear motion type is used is mainly for simplification of the mechanism.

  The setting unit 52 is a data input switch externally attached to the controller 50 as shown in FIG. 5, and the closing distances D3, D1, D0 and closing speeds V1, V2 of the tweezers 20 when gripping the workpiece. These data can be set and input for the opening speeds D0, D2, D3 and the opening speeds V3, V4 of the tweezers 20 when the workpiece is released.

   A solid line in FIG. 6 is a graph showing a temporal change in the closing distance of the tweezers 20 from the start of the workpiece gripping to the end of the workpiece gripping, and the closing speed is shown from the inclination of the graph. At the time t1 when the workpiece starts to be gripped, immediately before the workpiece gripping t2, and at the workpiece gripping t3, the closing distance of the tweezers 20 is set to D3, D1, and D0. The driving of the linear stepping motor 40 is stopped at the work gripping end t4. During the period I (t1 ≦ t <t2), the closing speed of the tweezers 20 is V1 (decreases linearly), and during the period II (t2 ≦ t <t3), the closing speed of the tweezers 20 decreases V2 (slowly in a curved line) ).

  A dashed line in FIG. 6 is a graph showing a temporal change in the opening distance of the tweezers 20 from the start of the workpiece opening to the end of the workpiece opening, and the opening speed is shown from the inclination of the graph. The opening distance of the tweezers 20 is set to D0 and D2 at the time t5 when the workpiece is opened and immediately after the workpiece is released t6. The driving of the linear stepping motor 40 is stopped at the work release end t7. In the period III (t5 ≦ t <t6), the opening speed of the tweezers 20 is V3 (slowly increases in a curve), and in the period IV (t6 ≦ t <t7), the opening speed of the tweezers 20 is V4 (increases linearly). ).

  Note that the pattern of the closing speed or opening speed shown in FIG. 6 is expressed by a polygonal line approximate expression or the like, and data such as coefficients and constants of the calculation expression is set and inputted through the setting unit 52.

  For the controller 50, in addition to the transporting stepping motor (not shown) that drives the movable part of the pick and place device to transport the workpiece W, the linear motion type stepping motor 40 is driven to grip the workpiece W. It is a control device to control. That is, detection signals from the origin sensor 71 and the pressure sensor 72, setting data of the setting unit 52, and the like are input, and pulse signals for driving the transporting stepping motor and the direct-acting stepping motor 40 according to a preset sequence. Thus, the workpiece W placed at a predetermined position is gripped and transported to another place.

  When controlling the driving of the linear stepping motor 40, the controller 50 obtains the open / close distance of the tweezers 20 in accordance with the detection result of the pressure sensor 72 as described above. While the closing distance and closing speed are controlled in accordance with the setting input of the setting unit 52 (indicated by the solid line in FIG. 6), the opening distance and opening speed of the tweezers 20 are input to the setting unit 52 when a workpiece release command is issued. (Shown by a dashed line in FIG. 6).

  The controller 50 is prepared in advance with a data table showing the relationship between the magnitude of the pressure acting on the tweezers 20 detected by the pressure sensor 72 and the magnitude of the opening / closing distance of the tweezers 20. The detection signal of the pressure sensor 72 is converted into the open / close distance of the tweezers 20. Further, a data table showing a pattern of a change in pressure acting on the tweezers 20 when the workpiece is gripped is prepared in advance, and whether or not the workpiece W is gripped by comparing the change in the detection signal of the pressure sensor 72 and the data table. It has come to measure. The process of the controller 50 when a workpiece gripping command, a workpiece transfer command, and a workpiece release command are issued in the process of sequentially processing the steps of the above sequence is as follows.

  At the time of a workpiece grip command, the direct acting stepping motor 40 is driven to rotate forward. That is, as shown in FIG. 4A, the arm portion 30 is moved downward, and the tweezers 20 is closed at a constant speed (closing speed V1) from D3 to D1. When the closing distance of the tweezers 20 indicates D1 immediately before gripping the workpiece, the closing speed of the tweezers 20 is reduced (closing speed V2). Thereafter, when the tweezers 20 has a closed distance D0 and the gripping of the workpiece W is detected based on the pressure-sensitive sensor 72, the forward drive of the linear motion stepping motor 40 is stopped. The same applies to the case where gripping of the workpiece W is not detected even though the tweezers 20 has a closing distance D0. Since the dimensions of the workpiece W are measured through the pressure-sensitive sensor 72 at the time of gripping the workpiece, the controller 50 can externally output as necessary. The deceleration start timing and the deceleration value may be set as appropriate according to the degree of partial scattering on the surface of the workpiece W when the workpiece is gripped.

  At the time of a workpiece transfer command, the direct acting stepping motor 40 is slightly forward driven. That is, the arm part 30 is moved slightly downward compared with the time of gripping the workpiece shown in FIG. 4B so that the gripping force of the tweezers 20 is increased.

  When the workpiece release command is issued, the direct-acting stepping motor 40 is driven in reverse. That is, the arm portion 30 is moved upward, and the tweezers 20 is opened at a predetermined speed (opening speed V3) until the closing distance reaches from D0 to D2. When the closing distance of the tweezers 20 indicates D2 immediately before gripping the workpiece, the opening speed of the tweezers 20 is accelerated (opening speed V4). Thereafter, when the opening of the workpiece W is detected based on the pressure-sensitive sensor 72, the reverse drive of the linear stepping motor 40 is stopped. This is the same when the detection signal of the origin sensor 71 becomes active. Note that the acceleration value and the acceleration stop timing may be set as appropriate according to the positional deviation of the workpiece W when the workpiece is released.

The driver 51 connected to the output stage of the controller 50 converts the pulse signal output from the controller 50 into an excitation signal and outputs it to the direct acting stepping motor 40 together with the direction signal.

  Hereinafter, the operation of the chuck device 1 configured as described above will be described.

  First, when a workpiece gripping command is issued, the direct-acting stepping motor 40 is driven to rotate forward. Then, the arm portion 30 shown in FIG. 4A is displaced in the downward direction in the drawing, and accordingly, a force acts in a direction in which the tip side of the tweezers 20 is closed, and the tweezers 20 is elastically deformed. After that, as shown in FIG. 4B, when the claw portions 24 a and 24 b of the tweezers 20 come into contact with the work W and the gripping of the work W is detected by the pressure sensor 72, the linear motion type stepping motor 40 Drive stops. Thus, the work W is gripped by the tweezers 20. When the driving of the direct acting stepping motor 40 is stopped, the holding force of the tweezers 20 is maintained constant by the stop holding force.

  Thereafter, when a workpiece conveyance command is issued, the linear motion type stepping motor 40 is slightly rotated forward and the gripping force of the tweezers 20 is slightly increased. In this state, the conveyance stepping motor is driven, and the workpiece W is conveyed in a predetermined pattern. When the workpiece W is conveyed and a workpiece release command is issued, the direct acting stepping motor 40 is driven in reverse. Then, the arm part 30 is displaced in the upward direction in the figure from the state shown in FIG. 4B, and as a result, the elastic deformation of the tweezers 20 is restored as shown in FIG. 4A. Return to state. When the opening of the workpiece W is detected based on the pressure sensor 72, the driving of the linear stepping motor 40 is stopped. Thus, the workpiece W is released from the tweezers 20.

  Note that the opening / closing speed and the opening / closing distance of the tweezers 20 at the time of gripping / opening the workpiece shown in FIG. What is necessary is just to set suitably according to the size, material, etc. of the workpiece | work W.

  In the case of the chuck device 1 configured as described above, the arm unit 30 is displaced with respect to the tweezers 20 to elastically deform the tweezers 20, and accordingly, the tip end side of the tweezers 20 is opened and closed to grip the workpiece W. / Since opening is possible, the overall structure of the device is simple and the number of parts is very small. Since the assembly work is also easy, the cost can be greatly reduced. In addition, since the opening / closing speed when opening and closing the tweezers 20 is controlled, the impact when gripping the workpiece W is alleviated, and part of the workpiece W is not scattered, and the workpiece W is opened. There will be no misalignment. In particular, by increasing or decreasing the closing speed from the time when the workpiece W is touched to the time when the workpiece W is gripped, the tact time can be shortened and the impact when gripping the workpiece W can be greatly reduced. Further, even when the workpiece W cannot be gripped, the driving of the direct-acting stepping motor 40 is stopped by the pressure-sensitive sensor 72 or the origin sensor 71, so that the tweezers 20 and the direct-acting stepping motor 40 are extraneous. No heavy burden. In addition, since the gripping force of the tweezers 20 is slightly increased when the work W is transported, the work W is not dropped from the tweezers 20 during transport. Therefore, it is possible to achieve high speed driving and high performance of the apparatus.

In addition, the chuck device according to the present invention is not limited to the application only of the pick and place device,
The same applies to robot hands and the like. The shape of the tweezers is not limited as long as the workpiece can be gripped on the tip side by its elastic deformation, and may be substantially V-shaped.
As for the arm part, as long as the tip side of the tweezer part can be opened and closed by its position displacement,
The form etc. which contact | contact / separate to the base end side of a tweezer part may be sufficient regardless of a shape etc. As long as the drive unit has a function of displacing the arm unit relative to the tweezers, the type thereof is not limited, and a general stepping motor, a combination of a motor, etc., and a motion conversion mechanism, or linear drive is possible. A cylinder or the like may be used, and it may be arranged separately from the apparatus main body.

1 Chuck device 10 Housing 20 Tweezers (tweezers)
21 Tweezers pipe (fulcrum)
22a, 22b Base end side portion 23a, 23b Tip end portion 24a, 24b Claw portion 30 Arm portion 31 Main body portion 32, 33 Arm 35a, 35b Roller portion 40 Direct acting type stepping motor (drive portion)
50 controller (control unit)
71 Origin sensor 72 Pressure sensor 721 Elastic material (elastic member)
722 Detector W Work

Claims (10)

A tweezers portion that can grip the workpiece on the distal end side, an arm portion that abuts on the proximal end side of the tweezers portion, a drive portion that moves in the base axis direction to displace the arm portion relative to the tweezers portion, and a tweezer portion A chuck device comprising: a control unit that controls driving of the driving unit so as to be opened and closed by elastic deformation.   2. The chuck device according to claim 1, wherein the tweezers are a fulcrum provided on the rear end side and a bifurcated member connected to the fulcrum, and the tip side is provided obliquely outward with respect to the base axis direction. A pair of proximal end sides, a pair of distal end sides connected to the distal ends of the pair of proximal end side portions, the distal end side being provided in an obliquely inward direction with respect to the proximal axial direction, and a pair of distal end sides A chuck device comprising: a pair of claw portions each provided so as to be connected to a tip of each portion and facing each other.   3. The chuck device according to claim 2, wherein the arm portion includes a main body portion connected to an output side of the driving portion, a pair of arms provided on the main body portion so as to extend in parallel to the base axis direction, and a pair of arms. A chuck device comprising: a pair of roller portions provided on a distal end side of the arm and abutting against a pair of base end side portions of the tweezers portion.   The chuck device according to claim 1, further comprising a pressure-sensitive sensor that detects pressure acting on the tweezers, wherein the control unit at least closes and / or closes the tweezers based on a detection result of the pressure-sensitive sensor. A chuck device characterized in that it has a function of controlling.   5. The chuck device according to claim 4, wherein the control unit obtains a close distance of the tweezers based on a detection result of the pressure sensor, and when the close distance indicates a predetermined value immediately before gripping the workpiece, the tweezers A chuck device having a function of decelerating the closing speed of the chuck.   5. The chuck device according to claim 4, wherein the control unit obtains an open distance of the tweezers based on a detection result of the pressure-sensitive sensor, and the tweezers when the open distance indicates a predetermined value immediately after the workpiece is opened. A chuck device having a function of accelerating the opening speed of the part.   5. The chuck device according to claim 4, further comprising a setting unit capable of setting and inputting at least a closing distance and / or a closing speed of the tweezers, wherein the control unit determines the closing distance and / or the closing speed of the tweezers. A chuck device having a function of performing control according to a setting input of a setting unit.   2. The chuck device according to claim 1, wherein the control unit has a function of controlling driving of the driving unit so that a gripping force of the tweezers is increased when the workpiece is conveyed. 3. A chuck device characterized by the above.   5. The chuck device according to claim 4, wherein the pressure-sensitive sensor includes an elastic body portion sandwiched between the tweezers and a detection unit that detects a force acting when the tweezers are opened and closed. A chuck device characterized by comprising:   2. The chuck apparatus according to claim 1, wherein a direct-acting stepping motor is used as the drive unit.

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