JP2583135B2 - Hand device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hand device used for automatically inserting a work such as a disk having a center hole around a shaft, for example.

(Prior art) Conventionally, as a hand device for automatic insertion of this kind of work,
A controlled object such as an arm of an industrial robot is provided with a work holder having an electromagnet for magnetic attraction, a suction cup for vacuum suction, or a gripper for gripping a work, and is attached or gripped by the work holder. A type in which a workpiece is forcibly inserted into a shaft is generally used.

(Problems to be Solved by the Invention) When the above-described conventional hand device is used in a place where cleanness is required for air, for example, in a clean room used in the field of manufacturing semiconductors, etc. The contact between the workpiece and the shaft becomes a problem. In other words, if the position where the workpiece is adsorbed or gripped by the workpiece holder deviates from the proper position, or if there is an error in the positioning accuracy of the controlled object, the center of the workpiece should be aligned with the axis of the shaft. Is difficult, and the insertion in the mismatched state causes contact between the shaft and the work. Even if the contact is weak, abrasion powder is generated due to so-called galling, which adversely affects the product. Therefore, when inserting the workpiece,
Avoid the forced insertion as much as possible to prevent the workpiece from coming into strong contact, and also insert it while detecting weak contact.If the degree of contact resistance rises above a predetermined level, interrupt automatic insertion. A backup system is required.

However, actually, as a method for detecting such contact, a load cell or the like is attached to the suction means or the gripping means, and when the contact resistance detected by the load cell or the like becomes a predetermined value or more, the assembling of the work is forcibly performed. In this method, only the strong contact between the workpiece and the shaft can be detected, and at the time of detection, it is already in strong contact, and the generation of wear powder is avoided. I can't get it.

The present invention has been made in view of such a point, and an object of the present invention is to provide a means for detecting a weak contact of a work with the shaft when the work is inserted into the shaft to reduce generation of dust accompanying the work insertion. It is to reduce as much as possible and to be able to use the hand device in a clean room or the like.

(Means for Solving the Problems) In order to achieve the above object, in the invention according to claim (1), a work having a center hole is held by a work holder and inserted into a shaft by its own weight. With
At the time of insertion, the relative displacement of the work with respect to the work holder is detected, and when the relative displacement is large, it is imitated that it is caused by the work being in contact with the shaft. , Stop the automatic insertion of the work.

That is, according to the present invention, a controlled body movable in two-dimensional directions including up and down by a driving means, a hand body supported on the controlled body in a horizontal direction via a floating mechanism, and a hand body A centering tool for a pair of shafts, which is supported so as to be able to move up and down and is urged to project downward,
A work holder that is concentrically disposed around the centering tool and is supported by the hand main body so as to be vertically movable, and holds the work so as to be vertically displaceable relative to itself by an external force; Displacement amount detecting means for detecting a relative displacement amount when the workpiece is vertically displaced relative to the workpiece holder when the workpiece held by the tool is inserted into the shaft, and a workpiece detected by the displacement amount detecting means. And control means for controlling the driving means so that the movement of the controlled body is stopped when the relative displacement amount with respect to the work holder exceeds a predetermined value.

(Operation) According to the above configuration, in the invention according to claim (1), when the work is inserted into the shaft, first, the controlled body moves down by the operation of the driving means, and the work holder is moved at the lower end thereof. Hold the work. Note that this holding state is a state in which the work can be vertically displaced relative to the work holder by an external force. Then, after the work holder is raised in that state, the controlled body moves above the shaft. Then
The controlled body moves down, the centering tool aligns the hand body and the work holder with respect to the shaft, and the work is inserted around the shaft by its own weight as the controlled body moves down. At this time, the relative displacement between the workpiece and the workpiece holder when the workpiece is vertically displaced relative to the workpiece holder is detected by the displacement detector, and when the workpiece is not in contact with the shaft, the workpiece is smoothly moved to the shaft without resistance. Since it is inserted, the relative displacement does not change. However, if the work makes any contact with the shaft,
The work relatively displaces up and down with respect to the work holder due to the resistance. If the relative displacement changes more than a predetermined value,
The operation of the driving means is stopped by the control means, and the guidance of the controlled object is stopped. Therefore, the contact with the shaft at the time of inserting the workpiece is detected quickly and accurately, and the insertion operation is stopped at the time of the detection, so that the generation of wear powder due to the contact between the two can be avoided as much as possible.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 3 show a hand device A according to an embodiment of the present invention.
1 shows the entire configuration. As shown in FIGS. 2 and 3, the hand device A includes a shaft B having a vertical axis.
To, for inserting a disk W as a work having a center hole W _1, the small-diameter shaft B continuous concentrically on the upper side of disk insertion portion B ₁ and said disk insertion section B ₁ of larger diameter and the bearing insert portion B ₂ of is formed. Further, the bearing insert portion B ₂ outer periphery is formed a bearing fitting groove B _3, the bearing C is fitted having an outer diameter smaller than the disk insertion portion B ₁ represents this fitting groove B ₃ . The disk W (work) is inserted into the outer periphery of the disk insertion portion B ₁ while dive the bearing C in a center hole W ₁ from the upper shaft B.

In FIGS. 1 to 3, reference numeral 1 denotes a controlled object movable in three dimensions, that is, horizontal and vertical directions, and is attached to, for example, an arm end of an industrial robot (not shown) constituting a driving unit. A hand body 3 is suspended and supported by the controlled body 1 via a floating mechanism 2 so as to be movable in the horizontal direction. The hand body 3 is concentrically and integrally joined at its upper end to an upper part 4 having a bottomed cylindrical shape opened upward and a cylindrical part 4a hanging down from the bottom of the upper part 4 at the upper end. The upper part 4 is formed with a flange 4b extending outward in the radial direction at the upper end of the upper part 4, and the hand body 3 is attached to the flange 4b. And is attached to the floating mechanism 2.

An air cylinder 6 for biasing a centering tool having a vertical cylinder axis at its center is attached to the inner bottom surface of the upper portion 4 of the hand body 3, and a piston rod 6 a of the cylinder 6 is attached to a bottom wall of the upper portion 4. And extends downward (inside the cylindrical portion 4a). A center hole 8 is formed through the center of the bottom wall of the lower portion 5, and a slider device 9 made of a ball spline is attached to the center hole 8. This slider device 9
Is a spline nut bolted to the bottom wall of the lower part 5
9a and a spline shaft 9b which is slidably and non-rotatably inserted through the spline nut 9a and passes on the axis of the piston rod 6a of the cylinder 6. The upper end of the spline shaft 9b is a joint 11 Is connected to the lower end of the piston rod 6a of the cylinder 6 through the lower end of the spline shaft 9b, and a cylindrical centering tool 12 having substantially the same diameter as the bottom wall of the lower portion 5 of the hand main body 3 is fastened and fixed. ing. Therefore, the centering device 12 is supported by the slider device 9 so as to be vertically movable with respect to the hand main body 3, and is constantly urged downward by the extension pressure of the cylinder 6. A recess 13 having a two-stage structure is formed on the lower surface of the centering device 12.
By fitting the bearing C of the shaft B into the lower step portion 13a of the shaft 13, the hand main body 3 and a work holder 17 described later are centered with respect to the shaft B.

In addition, a sensor mounting hole 14 is formed in a peripheral portion of the centering tool 12 so as to penetrate in a vertical direction.
It is open on the upper surface of the lower step 13a. Further, a capacitance type height sensor 15 is mounted in the sensor mounting hole. The height sensor 15 detects when the bearing C of the shaft B is completely fitted into the lower step 13a of the recess 13. The signal line of the height sensor 15 is inserted into a protective tube 16 slidably penetrating the lower wall 5 of the hand body 3, the cylindrical portion 4a of the upper part 4, and the bottom wall.

A substantially cylindrical work holder 17 is located in the range of the centering tool 12.
Are arranged concentrically with the centering tool 12. That is, the work holder 17 has a center hole 19, and the centering tool 12 (the bottom wall of the lower portion 5 of the hand body 3) is provided in the center hole 19. The lower ends of the guide rods 20, 20,... Are attached and fixed to the upper end of the work holder 17 at three equally circumferential positions. Each guide groove 20 is provided in the hand body 3
Slidably penetrates the bottom wall of the upper part 4 or the cylindrical part 4a, and the upper end thereof is fixed to a ring 21 disposed around the air cylinder 6, and includes three guide rods 20, 20,. The work holder 17 is supported by the hand main body 3 by 21.
A work holder lifting / lowering air cylinder 22 having a vertical cylinder axis is attached to a peripheral portion of the inner bottom surface of the upper portion 4 of the hand body 3, and a piston rod 22 a of the cylinder 22 extends upward, and an upper end thereof is provided. The work holder 17 is moved up and down between a raised end position and a lowered end position by expansion and contraction of the cylinder 22.

At the lower end of the work holder 17, three or more suction devices 27, 27,... For holding the disc W in a non-contact state are arranged at equal angular intervals in the circumferential direction. Each of the suction devices 27 includes a chamber 28 formed at the lower end of the work holder 17 and opening downward, and a suction unit disposed at the center of the chamber 28 and having an air outlet (not shown) opened on the lower surface. 30
The suction unit 30 is connected to an air supply source (not shown) through an air blowing pipe 31. The air from the air supply source is blown out from the suction unit 30 so that the disc W is air-cooled. Due to the Bernoulli effect, the workpiece is held by suction so as to be vertically displaceable relative to the workpiece holder 17 in a non-contact state.

Further, an annular suction passage 23 is formed at the upper end of the wall of the work holder 17, and this suction passage 23 communicates with the chamber 28 of each suction device 27 via a communication passage 23a. Also,
A suction tube 24 communicating with the suction passage 23 is screwed to the upper end of the work holder 17 in an airtight manner. The suction tube 24 is connected to a suction source (not shown) such as a suction pump. The air blown into the chamber 28 from the suction unit 30 of the device 27 is sucked into the air suction source through the suction passage 23 or the suction pipe 24 and collected, thereby preventing dust from scattering.

Air cylinders 32 having a cylinder axis extending in the radial direction of the hand main body 3 are attached to the outer peripheral surface of the cylindrical portion 4a of the hand main body 3 at three equally spaced positions in the circumferential direction. The piston rod 32a faces the outside of the hand body 3, and a suspension rod 25 guided by guide rods 33, 33 is suspended and supported at the tip of the piston rod 32a. The center of 17 is made to advance and retreat. In addition, each hanging rod
The lower portion of the disk holder 25 is located on the outer peripheral side of the work holder 17, and the lower end thereof can contact the outer peripheral edge of the disk W sucked and held by the suction devices 27, 27,. An opening / closing claw 34 made of a leaf spring is attached, and the disk W
When the workpiece W is sucked and held by the work holder 17 and transported, the opening and closing claws 34 are brought into contact with the outer peripheral edge of the disk W by extending and suspending the respective The movement (idle) of the vehicle is regulated.

Further, a height sensor 35 penetrating the upper wall of the chamber 28 and facing the inside thereof is disposed in each of the suction devices 27. The height sensor 35 is of a capacitance type similar to the height sensor 15 described above. The height sensor 35 detects the height position (relative distance) of the disk W sucked and held by each suction device 27 with respect to the work holder 17, and detects the relative height. If the position is out of the proper range, a signal is output. In this embodiment, the height sensor
35 constitutes a displacement detecting means for detecting a relative displacement when the disk W is displaced upward relative to the work holder 17.

As shown in FIG. 1, the output signals of the height sensors 15 and 35 are input to a control device 37 for controlling the operation of the robot. The control device 37 constitutes a control means according to the present invention and includes a CPU. Here, determines the transport disks W in the controller 37, will be described by Figure 4 the control procedure for inserting the shaft B, first, the change of the output signal of the height sensor 35 at step S _1. This determination is made as to whether the disk W has dropped during transport, or whether the disk W has contacted the shaft B during insertion and has been displaced up and down relative to the work holder 17, and the relative displacement amount has exceeded an appropriate range. Is determined. Then, if there is no change in the output signal of the height sensor 35, the disc W is not also dropping, does not even beyond the proper range displacement, executes the delivery and insertion of the shaft B of the disc W as in step S ₂ . Conversely, if there is a change in the output signal of the height sensor 35, the disc W, as in step S ₃
Forcibly stops the transfer or insertion of the data, and issues a warning such as an alarm.

 Next, the operation of the above embodiment will be described.

At the start of the operation of the hand device A, as shown in FIG. 1, a constant extension pressure is applied to the cylinder 6, and a downward urging force is applied to the centering tool 12 by the extension pressure. Further, the cylinder 22 is in a contracted state, the work holder 17 is at the processing end position, and the lower end surface of the suction part 30 of each suction device 27 is positioned at the lowermost position of the hand device A. Further, each cylinder 32 is in an extended state, and the opening / closing claw 34 at the lower end of the hanging rod 25 is at an open position retracted from the center of the work holder 17.

From the above state, first, the controlled body 1 moves down above the work mounting table D, and the entire hand body 3 descends, and the lower end surface of the suction unit 30 of each of the suction devices 27 is moved to the disk W (work) on the work mounting table D. ), The air supplied from the air supply source is blown out from the suction unit 30 of each suction device 27, and the disk W is moved to the work holder 17 (suction device 27) by the Bernoulli effect of the air blown out from the suction unit 30. ) Are lifted and held in a non-contact state with a certain interval.

Thereafter, the cylinder 22 is extended and the work holder 17 is raised to the rising end position, and each of the cylinders 32 is contracted so that the hanging rod 25 advances toward the center of the work holder 17 and the lower end of the hanging rod 25 is moved downward. The opening / closing claw 34 comes into a closed state in which it comes into contact with the outer periphery of the disk W. Then, in this state, as shown in FIG.
It is transported upward.

At this time, since the disk W is suction-held by each suction device 27 in a non-contact state, in a normal state, there is a possibility that the disk W may fly out or shake in the horizontal direction due to inertia or the like.
However, in this embodiment, the opening / closing claw 34
, The movement of the disk W during transport is restricted by the opening / closing claw 34, so that the above problem does not occur.

Further, since the disc W is held in a non-contact state by the suction unit 30 of each suction device 27, the work holder for the disc W is held.
There is no contact with 17 itself, which can contribute to a reduction in generation of wear powder.

After the disk W is transported above the shaft B, the controlled body 1 moves downward. As shown in FIG. 3, the bearing C of the shaft B is provided on the lower step 13a of the recess 13 of the centering device 12.
Are completely fitted, and when a signal indicating this is output from the height sensor 15, the centering is completed. Thereafter, open closing pawl 34 of the hanger bar 25 the lower end by the elongation of the respective cylinder 32 is retracted, then the disk insertion portion B ₁ around the disc W is shaft B further downward movement is the controlled 1 It is inserted.

At this time, the disk W is held by the suction devices 27 and 2 of the work holder 17.
7, the disc W is inserted by its own weight because the disc W is held so as to be relatively displaceable up and down in a non-contact state. Therefore, even if the disk W makes little contact with the shaft B, the disk W is displaced sensitively with respect to the work holder 17, and the detection accuracy can be improved.

Further, since a constant extension pressure is applied to the cylinder 6, the force with which the centering tool 12 presses the bearing C of the shaft B becomes constant, and the shaft B can be stably held.

If the disc W falls during the transfer or insertion of the disc W, or a contact occurs during the insertion of the disc W into the shaft B, and the disc W is vertically displaced beyond an appropriate range, a signal from the height sensor 35 is output. Is received by the control device 37,
When the operation of the robot is stopped, a warning is given to that effect.

Then, as shown by a virtual line in FIG.
The descending movement of the controlled body 1 stops at the descending end position of 17, thereafter, the air blowing from the suction section 30 of each of the suction devices 27 stops, and the disk W is no longer held by the suction devices 27. Falls on the step of the shaft B. Thus, the insertion process for one disk W is completed. Thereafter, the same operation as described above is repeated for each disk W, and a plurality of disks W, W,.

Therefore, in this embodiment, as described above, if there is a contact between the disk W and the shaft B, even if the contact is weak, if the contact is abnormal, a signal is output by the height sensor 35 and the insertion operation is stopped. Therefore, generation of abrasion powder due to contact between the two can be prevented as much as possible.

In the above embodiment, the disk W is sucked and held in a non-contact state by the suction unit 30 of each suction device 27 in the work holder 17, but the work holder 17 may be changed as shown in FIG. Good.

That is, FIG. 5 shows another embodiment of the present invention.
The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.)
The three holder bodies 18a, 18a, ... attached to the lower end of 20
The upper end of the holder main body 18a is pivotally supported at the upper end so as to be swingable, and the disk W
Support claw 18b engaged so as to hold the outer peripheral edge of
, And the support claws 18b are driven by a driving device (not shown). A height sensor 35 is attached to each of the holder main bodies 18a.

Therefore, in this embodiment, before the disc W is held, the support claws 18b of the work holder 17 are open, and the disc W is supported by the work holder 17 by closing the support claws 18b. It is conveyed above the shaft B in this state. When the shaft B of the disk W is inserted, the contact between the two is detected by the height sensor 35 as in the above-described embodiment. Therefore, also in this embodiment, the same operation and effect as the above embodiment can be obtained.

The present invention can of course be applied to the case where a work other than the disk W is inserted into the shaft B as in the above embodiment.

Also, instead of the height sensor 35, a flow sensor for measuring the flow rate of the air blown from the suction unit 30 in the middle of the air blowing pipe 31 is provided, whereby the relative displacement amount between the disk W and the work holder 17 is changed. May be detected indirectly.

(Effects of the Invention) As described above, according to the invention of claim (1), when a work having a center hole is centered by the hand device and automatically inserted into the shaft, the work is inserted by its own weight. In addition, the relative amount of vertical displacement of the workpiece held by the workpiece holder with respect to the workpiece holder at the time of insertion is detected, and when the displacement exceeds an appropriate range, it is determined that the workpiece has abnormally contacted the shaft. By forcibly stopping the insertion of the work, abnormal contact of the work with the shaft can be detected quickly and sensitively, and generation of wear powder due to the contact can be avoided as much as possible. Therefore, the present invention has a practically excellent effect that the hand device can be used without any trouble even in a clean room or the like where cleanliness is required.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a cross-sectional view of a hand device showing a state before suction holding of a disk, FIG. 2 is a diagram corresponding to FIG. 1 showing a state of holding and transporting a disk, FIG. 3 is a diagram corresponding to FIG. 1 showing a disc inserted state, and FIG. 4 is a flowchart showing a control procedure in the control device. FIG. 5 is a sectional view showing a main part of another embodiment. A: Hand device 1: Controlled object 2: Floating mechanism 3: Hand body 6: Centering tool biasing cylinder 12: Centering tool 17, 17 ': Work holder 18b: Support Claw 22 ... Cylinder for lifting and lowering work holder 27 ... Suction device 32 ... Cylinder 35 ... Height sensor (displacement amount detecting means) 37 ... Control device (control means) B ... Shaft C ... Bearing W ... Disc (work) W ₁ …… Center hole

Claims (1)

(57) [Claims] 1. A hand device for holding a work having a center hole and inserting it around a shaft, comprising: a controlled body movable in two-dimensional directions including up and down by a driving means; and a floating mechanism mounted on the controlled body. A hand main body movably supported in the horizontal direction via a shaft; a centering device for a pair of shafts supported movably up and down by the hand body and protruding downward; and around the centering device. A work holder, which is concentrically arranged and is vertically movably supported by the hand main body, and holds the work so as to be vertically displaceable relative to itself by its external force; and Displacement amount detecting means for detecting a relative displacement amount when the work is vertically displaced relative to the work holder at the time of insertion into the shaft; and a relative position of the work detected by the detection means with respect to the work holder. Position quantity hand device which is characterized in that is a control means for controlling the driving means so that movement of the controlled member is stopped when it exceeds a predetermined value.