JPS6363339B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a workpiece loading/unloading device attached to a machine tool such as a lathe, and more specifically, a workpiece clamp provided at the end of the workpiece loading/unloading device for handing the workpiece to the chuck of the machine tool. Regarding the configuration of the device.

When handing a columnar workpiece to a chuck in a machine tool, such as a lathe, the important points are (a) that the chuck can grip the workpiece so that the workpiece does not shift in the direction of entry and exit, and (b) that the chuck must be gripped properly. (c) The chuck can be held in the correct axis position so that there is no inclination to the axis, and (c) Excessive force that could damage the chuck, workpiece, or clamping device will not be applied during the handing process. be.

If such work handing work is performed manually, it is possible to perform the correct processing taking into account the points shown in each of the above (a) to (c), but with the automated workpiece loading/unloading equipment that is being used frequently these days, The problem is that it is not possible to perform the correct operation that satisfies each of the above requirements.

Regarding the points in the previous (a) and (b), the gripping axis of the gripping tool at the end of the arm and the gripping axis of the chuck should be controlled so that they align correctly, and at the same time, the amount of advance of the gripping tool should be controlled to be just the right amount. Of course, this can be solved by controlling the loading/unloading device precisely, but in reality, each part of the loading/unloading device must have a precise structure with no play, and it is also necessary to improve the control accuracy for positioning. There is a problem that the cost of the equipment is very high, and furthermore, the chuck and clamping tools for gripping the workpiece must be operated at the right time and with the appropriate force.
As a result of excessive force being applied to various parts due to slight axis deviation or excessive advance, accidents often occur that damage the weakest of the chuck, workpiece, and clamping tool.This problem can also be solved through design and control. The reality is that there are still issues that need to be addressed.

In view of these facts, the present invention performs two-axis control of advancement and clamping of the workpiece clamping device in an appropriately timed and sequential manner, and also adjusts the clamping pressure during clamping. The workpiece is accurately gripped by the chuck at a predetermined position, and the workpiece gripped by the clamping tool is handed over to the chuck with smooth movement, so that the workpiece can be carried in without causing any damage. In particular, a pressing piece having a flat surface that can come into contact with the end surface of the workpiece is provided close to the back of the hand side of the clamping tool for holding the workpiece, so that it can move integrally with the clamping tool. In the fluid pressure circuit that controls the two axes, the actuator for the clamping shaft is operated under high pressure on the clamping side, and the actuator for the horizontal axis for forward movement is operated under high pressure and high speed to control the pressing piece and the clamping tool. The first stage approaches to rapidly approach the chuck, the second stage approaches switches the horizontal axis actuator to low pressure and low speed operation to bring the chuck closer to the chuck at a slow speed, and in conjunction with this second stage approach, the gripping shaft actuator The actuator is switched from high-pressure operation to low-pressure operation, and the work is held under a light force that allows the work to slide against the clamping tool. After the work is clamped by the chuck and the pressing piece, the work is held by the chuck. The present invention is characterized by a configuration comprising a control means for sequentially performing each process of releasing the workpiece by changing the actuator for the clamping shaft to the release side operation before and after the gripping of the workpiece.

Hereinafter, specific contents of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic plan view showing the skeleton of an example of the device of the present invention. It includes a base 1 that is given reciprocating reciprocating motion, an arm 2 extending from the base 1 in a direction perpendicular to the rotation axis R, and two clamps 3A and 3B provided at the tip of the arm 2. and
The arm 2 is disposed between a machine tool 4 such as a lathe having a chuck 5 parallel to the rotation axis R, and a transfer device 6 that transfers the workpiece to a predetermined position P on the side of the chuck 5. By rotating forward and backward by a predetermined angle θ, the transfer machine 6 receives the unprocessed work W ₁ and hands over the processed work W ₂ .
Further, on the machine tool 4 side, the machined workpiece W ₂ is received and the unprocessed workpiece W ₁ is handed over.

In this case, the two clamping tools 3A and 3B are placed in a back-and-forth relationship on the machine tool 4 side in the extension direction of the gripping shaft extending in the horizontal direction of the processing 5, and on the transfer machine 6 side vertically above the predetermined position P. This is possible by positioning the base 1 so that the center of rotation of the arm 2 lies on a vertical line passing through the midpoint of a perpendicular line extending from the predetermined position P to the axial extension line of the chuck 5. However, like this, there are two clamping tools 3A,
3B are arranged back-to-back with the center axis of arm 2 as the axis of symmetry.The reason why the arms 2 are arranged back-to-back with the center axis of arm 2 as the axis of symmetry is that the unprocessed workpiece W ₁ is carried in and the processed workpiece is carried in during one cycle of normal and reverse rotation of arm 2. This is because the device according to the _present invention has a single structure in which only one clamping tool 3A is provided at the tip of the arm, rather than a pair of clamping tools. are also within the scope of the invention.

The arm 2 rotates around the rotation axis R;
A linear motion in the direction of the rotation axis R, that is, a horizontal axis X direction that moves the clamps 3A, 3B toward or away from the extension direction of the gripping shaft of the chuck 5, and a rotational motion centered on the automatic _R0 . However, the device according to the present invention is not limited to the three-axis structure shown in FIG. In addition to the three axes, a clamping tool 3 as described below
By providing the movement of the clamping shaft G that causes the clamping and releasing of A and 3B, it is possible to easily provide a workpiece clamping device that can move the clamping tool 3A three-dimensionally.

Reference numeral 7 denotes an actuator for the horizontal axis X, which is provided so as to be able to move the base 1 forward and backward in the direction of the rotation axis R. The operation of this actuator 7 causes the clamping tool attached to the tip of the arm 2 to move forward and backward in the direction of the rotation axis R. 3A and 3B are formed so as to be able to approach and separate from the chuck 5 on the extension of its grip axis.

The clamping tools 3A and 3B have the same structure. Therefore, referring to FIGS. 2 and 3, the clamping tool 3A will be explained using the clamping tool 3A. It has a piece 8 and a clamping piece 9 in the form of an arcuate member, and the proximal ends 8 _-1 and 9 -1 of both clamping pieces 8 and ₉ are formed into racks facing each other, and a space between the racks is formed. When the base end 8 _-1 of one of the clamping pieces 8 is moved in a reversible linear manner by the actuator 11A disposed at an appropriate location on the arm 2, both clamping pieces 8, 9
The clamping parts _8-2 and _9-2 come into contact and separate while maintaining the same distance from the center of the clamping shaft G, so that even if the diameter of the workpiece changes, it can be gripped and released centripetally. .

The pair of clamping tools 3A and 3B are provided at the tip of the arm 2 in a back-to-back arrangement with the rotational axis _R0 of the arm as the axis of symmetry, and the arm 2 is rotated around the rotational axis _R0. When rotated 180 degrees, their positions change.

Note that the clamping tool 3A according to the present invention is shown in FIGS. 2 and 3.
At least two
Various modifications are conceivable as long as the peripheral surface of the workpiece W ₁ can be clamped from a direction perpendicular to the axis of the workpiece W 1 by the clamping pieces 8 and 9 approaching each other centripetally.

Pressing piece 1 against the above pair of clamping tools 3A, 3B
2 are placed close to each other at the tip of the arm 2, and the pressing piece 12
can be moved integrally with the clamping tools 3A and 3B.

This pressing piece 12 is, for example, a flat plate-like piece having a flat surface that can come into contact with the end surface of the workpiece _W1 , and
Although the clamping tools 3A and 3B are disposed adjacent to each other on the back side of the hand, in the illustrated example, the clamping tools 3A and 3B are arranged back to back in an axially symmetrical manner, so that both clamping tools 3
The arrangement is such that it is inserted between A and 3B.

The specific structure of the device of the present invention has been described above. Next, the fluid pressure circuit for operating each operating shaft of this device will be explained with reference to FIG.

(a) Fluid pressure circuit of X-axis actuator 7, 4-port position double solenoid solenoid valve 13
, a normally open pressure reducing valve 14 with a constant secondary pressure (for example, 10 kg/cm ² ) inserted in the pump line, and a variable temperature-compensated flow rate regulating valve 15 inserted in the reservoir line. On the other hand, a manual throttle valve 16 and a normally closed secondary pressure constant (e.g. 2
Kg/cm ² ) relief valve 17 and a 4-port 2-position spring offset solenoid valve 18 are provided in the drain line for controlling the pressure reducing valve 14.

When the arm 2 and the clamping tools 3A, 3B are integrally brought closer to the chuck 5 on the machine tool 4 side, the operation is performed as follows.

When only the solenoid _S2 of the electromagnetic valve 13 is energized, the secondary pressure of the pressure reducing valve 14 is set to 10 kg/cm ² , so that the actuator 7 operates under high pressure and high speed, and the arm 2, clamping tools 3A, 3B quickly approaches Chuck 5.

When the workpiece W ₁ held by the clamping tool 3A approaches the chuck 5, this rapid downward approach (first stage approach) is performed, and then the solenoid valve 18 is activated by a command from an appropriate position detector. Further energize solenoid _S3 .

Thus, the secondary pressure of the pressure reducing valve 14 is reduced to 2 kg/cm ² by the operation of the relief valve 17. As a result, the actuator 7 operates at low pressure and low speed (second stage approach), and the workpiece W ₁ Check 5
The chuck 5 can be inserted into the chuck 5 by slowly approaching the chuck 5 without applying excessive pressing force.

When the clamping tool 3A advances a predetermined distance and hits the stopper part of the chuck 5, the pressing piece 12 and the rear end surface of the workpiece _W1 come into contact with each other, as will be described later. The work W ₁ is held between the two under a weak pressing force of about 2 kg/cm ² .

In the circuit shown in Figure 4, in accordance with the command from the detector, solenoid S ₂ is deenergized and at the same time solenoid S ₁ is energized, and solenoid S ₃ is deenergized to operate under high pressure and high speed. It is formed so that it can be switched to reverse.

(b) Fluid pressure circuit of actuator 11A for clamping shaft G, 4 ports 3 positions AR connection, spring center double solenoid solenoid valve 19, check valve 20 connected in series in the pump line, manual throttle valve 2
1, a 2-port 2-position spring offset solenoid valve 22, and when the solenoid valve 22 is opened, the pump line and the B port of the solenoid valve 19 (when the clamping tool 3A is operated in the clamping direction, the pump line is connected to the A normally open pressure reducing valve 23 with a constant secondary pressure (for example, 2 Kg/cm ² ) is provided, which is connected between the terminal and the port on the conducting side.

When the clamping tool 3A is operated to the release side by this fluid pressure circuit, the solenoid of the solenoid valve 19
It suffices to energize _S3 , and conversely, to operate to the clamping side, it suffices to energize solenoid _S4 of the solenoid valve 19. In this case, the workpiece can be clamped under high pressure.

As mentioned in the description of the operation described later that it is necessary to lightly clamp the workpiece W1, the clamping force of the clamping tool 3A needs to be weakened when the chuck 5 grips the workpiece _W1 . In that case, the pressure applied to the piston of the actuator 11A can be reduced to 2 kg/cm ² by energizing the solenoid S ₅ of the solenoid valve 22 with the solenoid valve 19 in the neutral position, thereby greatly weakening the clamping force. I can do it.

Note that the operation of supporting the workpiece _W1 with this weak clamping force may be performed in conjunction with the second-stage approach operation of the horizontal axis X, but in addition, after switching the actuator 7 to low-speed movement, After moving the actuator 7 for a predetermined distance or for a predetermined time, it may be configured to have a weak clamping force, and in short, it may be selected as appropriate depending on the use of the chuck 5.

The operation toward the release side is performed simultaneously with the gripping of the workpiece _W1 by the chuck 5.

(c) Fluid pressure circuit for the rotation axis R and rotation axis R ₀ Although the fluid pressure circuits related to the above two axes are not shown, the rotation axis R is simply rotated by a predetermined angle θ between the machine tool 4 and the transfer device 6. Since only the following operations are required, the rotation axis R can be driven by a simple fluid pressure circuit.

On the other hand, regarding the rotation axis R ₀ , the unprocessed workpiece W ₁
In addition to the operation of rotating 180° when replacing the machined workpiece W ₂ with the processed workpiece W 2, the phase angle (a fixed value )
only requires an operation to rotate during turning,
Since both are fixed angles determined at the time of design, it is possible to drive the rotation axis R ₀ with a simple fluid pressure circuit in this case as well.

The fluid pressure circuits related to each axis have been described above, and next, the handing of the workpiece _W1 by the apparatus of the present invention will be outlined.

Column workpiece held by clamping tool 3A
By controlling the rotation R and rotation R ₀ of the arm 2, the W ₁ is carried to a point where it coincides with the grip axis of the chuck 5 on an extended line.

In this case, the gripping operation is first performed so that a slight gap may exist between the end surface of the workpiece _W1 being gripped and the pressing piece 12.

Next, a first approach operation is performed in which the solenoid _S2 of the solenoid valve 13 is energized to cause the clamping tool 3A and the pressing piece 12 to rapidly approach the chuck 5.

When the tip of the workpiece W ₁ reaches a position where it is flush with the chuck 5 or slightly penetrated by this first stage approach operation, a command from the detector detecting this causes the solenoid of the solenoid valve 18 to be activated. S ₃ is applied, and the first stage approach operation is changed to the second stage at low pressure and low speed.
At the same time as switching to stage approach operation, solenoid _S5 of solenoid valve 22 is energized while solenoid valve 19 remains neutral.

In this way, a state of light contact is created between the workpiece W ₁ and the clamping pieces 8 and 9, and the clamping tool 3A clamps the workpiece W ₁ with a light force that allows it to slide while moving at a gentle speed. Closer to chuck 5,
Workpiece W ₁ can be pushed into chuck 5.

When the unprocessed work W ₁ reaches the maximum insertion position where the tip is in contact with the innermost part of the chuck 5 and does not move forward any further, only the clamping tool 3A moves against the circumferential surface of the work W ₁ . It moves forward while making sliding contact.

This forward motion is applied to the workpiece W ₁ which is braked.
This continues until the end face of the chuck 5 comes into contact with the pressing piece 12, and at the point of contact with the pressing piece 12, the state in which the chuck 5 and the pressing piece 12 lightly sandwich the unprocessed workpiece _{W1 is} maintained.

Therefore, there is no need to apply excessive force to any of the workpiece W ₁ , the clamping tool 3A, and the chuck 5, and there is no risk of damage and accidents, and the workpiece can be transferred smoothly.

When the workpiece W ₁ is kept in the clamped state in this way, the actuator 7 is brought to an approach stop by switching the approaching side operation to the retracting side in conjunction with the gripping operation of the chuck 5, and the actuator 11A is moved to the releasing side. The handing over of workpiece W ₁ is hereby completed by turning it into operation.

In this process of handing over a series of workpieces, especially when the workpiece W ₁ comes to be affected by mechanical force from both the chuck 5 and the clamping tool 3A, the clamping tool 3A
The clamping action of the workpiece W 1 is changed to a light force that is sufficient to keep the posture of the workpiece W ₁ stable, so that no excessive force is applied to each part, and furthermore, until the workpiece W 1 is securely clamped by the chuck 5. Since the workpiece _W1 is supported by the chuck 5 and the pressing piece 12, the clamping tool 3A can be smoothly released while maintaining the posture of the workpiece _W1 .

The workpiece clamping device of the present invention operates two axes, a horizontal axis X that moves the clamping tool 3A toward the chuck 5 from the extending direction of the gripping shaft of the chuck 5, and a clamping shaft G that clamps and releases the clamping tool 3A. In a device for handing a columnar workpiece W ₁ held by a clamping tool 3A to a chuck 5, a pressing piece 12 having a flat surface capable of contacting the end surface of the workpiece _W1 is provided at the tip of the arm close to the back side of the gripping tool 3A. Then, remove the clamping tool 3A and the pressing piece 12.
The clamping shaft G
The actuator 11A for the workpiece _W1 is operated under high pressure on the clamping side.The actuator 7 for the horizontal axis
and a first stage approach in which the pressing piece 12 is rapidly approached to the chuck 5, the actuator 7 is switched to low pressure and low speed operation, and the clamping tool 3A and the pressing piece 1 are
2 approach slowly to chuck 5,
In conjunction with this second stage approach, actuator 11A
is switched from high-pressure operation to low-pressure operation, the work W ₁ is held under a light force that allows the work W ₁ to slide, and after the work W ₁ is clamped by the chuck 5 and the pressing piece 12, the chuck is Work by 5 W ₁
The horizontal axis X and the clamping axis G are used to control the control means for sequentially performing each release process of the workpiece _W1 , which changes the actuator 11A to release side operation before and after the gripping of the workpiece W1.
This is provided in the fluid pressure circuit for axis operation including two axes, and when the work W ₁ is handed over to the chuck 5, the gripping tool 3A holds the work W 1 in a stable posture immediately before and after handing the work W ₁ to the chuck 5. The work is done under light pressure that maintains the
Even if the axis of W ₁ and the gripping axis of chuck 5 do not match exactly, it is possible to smoothly grip the workpiece without applying excessive force to chuck 5. There is no need to apply any external force that could cause damage to the workpiece W ₁ and the clamping tool 3A.

Furthermore, since the pressing piece 12 cooperates with the chuck 5 to clamp the workpiece W ₁ from both sides with a light force, it is possible not only to prevent damage to the chuck 5 caused by strong pressing, but also to prevent damage to the chuck 5 caused by strong pressing. Clamping tool 3A
The posture of the work W ₁ can be stably maintained during the transition period when the support is switched from the chuck 5 to the chuck 5, and the releasing operation of the clamping tool 3A can be easily and easily performed.

Furthermore, when handing over a workpiece, unlike the awkward and unreasonable movement that would occur if the workpiece _W1 is held with a similar strong clamping force, the present invention allows handing over a workpiece that corresponds to the movement of a person's fingers. It is a clamping device that can perform smooth but light operation, and prevents misalignment,
This invention is extremely useful in promoting unmanned work, as it enables the handing over of workpieces without any confusion or damage.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing the skeleton of an example of the device of the present invention, FIG. 2 is a plan view showing the main parts of a specific embodiment, FIG. 3 is a front view, and FIG. 4 is a fluid flow diagram of the device of the present invention. FIG. 3A...Holding tool, 5...Chuck, 7...Horizontal axis actuator, 8...Holding piece, 9...Holding piece, 11A
...actuator for clamping shaft, 12...pressing piece, G...
Clamping axis, W ₁ ...workpiece, X...horizontal axis.

Claims (1)

[Claims] 1 A clamping tool 3A capable of clamping the circumferential surface of the workpiece W ₁ from a direction perpendicular to its axis using clamping pieces 8 and 9 that approach centripetally from at least two directions.
at the tip of the arm, and a horizontal shaft X that allows the clamping tool 3A to move toward and away from the chuck 5 having a horizontal gripping shaft from the extending direction of the gripping shaft, and the clamping pieces 8 and 9 are moved toward and away from each other. The clamping tool 3A is
In the workpiece holding device for delivering the columnar workpiece W ₁ held by the chuck 5 to the chuck 5, the workpiece
Pressing piece 12 having a flat surface that can come into contact with the end surface of _W1
is provided on the tip of the arm in close proximity to the back side of the clamping tool 3A, so that the clamping tool 3A and the pressing piece 12 can move together, while the fluid pressure circuit includes:
The actuator 11A for the clamping shaft G is operated under high pressure on the clamping side.The actuator 7 for clamping the workpiece _W1 and the horizontal axis The first stage approaches the chuck 5, and the second stage approaches the chuck 5 by switching the actuator 7 to low pressure and low speed operation to slowly approach the clamping tool 3A and the pressing piece 12 to the chuck 5.
stage approach, switching the actuator 11A from high pressure operation to low pressure operation in conjunction with this second stage approach;
The work W ₁ is held under a light force that allows the work W ₁ to slide, and after the work W ₁ is clamped by the chuck 5 and the pressing piece 12, the work W ₁ is gripped by the chuck 5. A workpiece W ₁ that causes the actuator 11A to operate on the release side.
A workpiece holding device characterized by comprising a control means for sequentially performing each release process.