JPH05212496A - Device for housing core - Google Patents

Abstract

PURPOSE:To prevent the chipping of a core by clamping the core with suitable clamping force matched with the strength of the core and to improve the versatility of a core housing device so as to be able to clamp the core with the suitable clamping force even to the positional deviation of the core or the different kinds of the cores. CONSTITUTION:This device is provided with actuators 1-3 provided on a robot hand 20 and capable of stopping the working at an optional position and clamping pawls 4-6 fitted to the actuators 1-3 through a holding force detecting sensors 7-9 and a controller for controlling the working of the actuators 1-3 based on the clamping force of the clamping pawls 4-6 detected with holding force detecting sensors 7-9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core housing device for housing a core in a main mold in a casting process.

[0002]

2. Description of the Related Art Heretofore, some of the core-contracting devices have been disclosed, for example, in Japanese Patent Application Laid-Open No. 63-183745 or Japanese Utility Model Application Laid-Open No. 2-87542 filed by the present applicant.

[0003] In these core receiving devices, a clamping device for clamping the core is constructed to be movable between the core transfer pallet and the main mold in the main mold line. According to this, the work to transfer the cores placed on the transfer pallet to the main mold and to put them in the predetermined position of this main mold is done automatically without manual labor, thereby saving labor of the cores. I was able to.

[0004]

However, there are the following problems in the conventional core receiving device, especially in the clamp device.

That is, in the conventional clamping device, since the gripping claw is moved by, for example, an air cylinder to grip the core, the gripping claw (air cylinder) can be stopped at an arbitrary position. However, the grip position was fixed. Further, since the gripping position is fixed, it is difficult to clamp the core with the core accurately positioned when the core is misaligned or the core size varies. It is not possible to deal with the child as it is, and in this case, it is necessary to mount a separately prepared jig on the clamp device or prepare a dedicated transfer pallet.

Also, since the clamping mechanism is based on the rod projecting force (air pressure x piston diameter) of the cylinder, the gripping force cannot be adjusted arbitrarily, and therefore the gripping force is optimally gripped according to the strength of the core. It was difficult to do so, and the core was frequently scraped. Even if the core is scraped, the gripping force cannot be changed, and the gripping force becomes unstable, which may cause the gripped core to fall. It was

As described above, the conventional clamping device is not versatile with respect to the cores of various shapes, so that the core-storing process becomes a bottleneck in automation especially in the multi-product casting process. However, since the gripping force cannot be changed according to various situations, there is a problem in that the reliability against abnormality during core clamping is lacking.

The present invention has been made in view of the problems relating to the clamp device in the conventional core-retracting device,
A core with high versatility for cores of various shapes, and with a clamp device that can flexibly cope with changes in the gripping force due to scraping of the core and prevent the core from falling down. The purpose is to provide a payment device.

[0009]

In order to solve the above-mentioned conventional problems, the present invention uses an actuator provided on a robot hand and capable of stopping operation at an arbitrary position, and a gripping force detection sensor in the actuator. It is characterized in that it is provided with a grip claw attached and a control device for controlling the operation of the actuator based on the grip force of the grip claw detected by the grip force detection sensor.

[0010]

According to the above construction, the grip claw can be stopped at an arbitrary position by stopping the operation of the actuator,
When gripping the core on the transport pallet, the actuator is operated to bring the gripping claw into contact with the core, and the gripping force at this time is detected by the gripping force detection sensor, and this gripping force is commensurate with the strength of the core. When the appropriate value is reached, the operation of the actuator is stopped and the grip claw is fixed at this position. As a result, the core is gripped with an appropriate force, and core scraping is prevented.

Further, since the gripping claw is moved until the gripping force reaches an appropriate value, the gripping position is not fixed but adapted to the position of the core, and the positional deviation is absorbed. It

[0012]

Embodiments of the present invention will now be described with reference to FIGS. In the figure, as an example, the case where the core 40 used in the casting process of the differential carrier is housed in the main mold 42 is illustrated. First, the configuration of mainly the clamp device of the core housing device of this embodiment will be described with reference to FIGS. 1 to 3.

This clamp device is attached to the tip of a general-purpose multi-axis type robot hand 20, and the clamp device is operated by operating the robot hand 20 along a predetermined moving path stored by teaching. The core 40 that has been conveyed from the process and is in a standby state at a predetermined position.
And a main mold 42 in which the core 40 is stored can be moved.

Now, this clamp device has a base 10 attached to the tip of the robot hand 20, and actuators 1 to 3 arranged at three positions on the periphery of the base 10.
3 and the rods 1a to 3a of the actuators 1 to 3,
Gripping claw 4 attached via gripping force detection sensors 7-9
~ 6 and.

Arm-shaped sub-bases 10a, 10a are attached in a bifurcated manner to one end side (the right end side in FIG. 1) of the lower surface of the base 10, and both the sub-bases 10a, 10a.
Actuators 1 and 2 are attached to the rod 1 at the tip of a
It is attached with a and 2a facing each other.

The actuator 3 is based on this base 1
0 is attached to the other end side (the left end side in FIG. 1) of the lower surface of 0 in a state in which the rod 3a is directed to the actuators 1 and 2, and the rod 3a of the actuator 3 is moved in the left-right direction in FIG. The actuators 1 to 3 are arranged so that the rods 1a and 2a of the actuators 1 and 2 respectively stroke in a direction orthogonal to the plane of the drawing.

Each of the actuators 1 to 3 uses the pulse motors 1c to 3c as a drive source, and the rods 1a to 3a.
The actuators 1 to 3 are configured in the same manner as described above by moving the holding claws 4 to 6 in the horizontal direction.

That is, the structure of the actuator 3 shown in cross section in the figure will be described as an example.
A pulse motor 3c as a power source is attached to the left end of the figure, and the output shaft 3d of the pulse motor 3c is
A nut 3e rotatably mounted inside a cylindrical case 3b via a bearing (not shown) is connected to rotate integrally. The nut 3e is attached to the rod 3
A screw shaft portion 3f formed in the left half of a in the figure is screw-fitted, and the screw shaft portion 3f and the nut 3e form a ball screw. A trapezoidal screw is used for this ball screw, so that the rod 3a does not move due to an external force even when the pulse motor 3c is cut off due to a power failure or the like. For this reason,
The gripping claw while gripping the core does not move idly, and the gripping force is retained as it is.

The rod 3a is supported in the cylindrical case 3b via a ball spline (not shown) so as to be slidable in the axial direction and non-rotatable around the axis, whereby the pulse motor 3c is rotated at a predetermined angle or a predetermined angle. When the rod 3a is normally or reversely rotated by the number of rotations, the rod 3a strokes to the left or right in the figure by a distance corresponding to it, and can be stopped at any position by stopping the pulse motor 3c. The stroke amount of the rod 3a is detected by a stroke sensor (differential transformer) 17. This stroke sensor 17
Is connected to a control device 50 described later. The stroke sensor 17 is not shown in FIGS. 1 and 2.

The support rod 11 is attached to the tips of the rods 1a to 3a of the actuators 1 to 3 constructed as described above.
13 are orthogonal to the rods 1a to 3a and are attached so as to project downward.

Each of the support rods 11 to 13 is divided into an upper part and a lower part, and the upper and lower divided rods are connected by gripping force detection sensors 7 to 9. That is, when the support rod 13 attached to the rod 3a is described as an example, the support rod 13 is divided into an upper rod 13a and a lower rod 13b, and the upper rod 13a is connected to the rod 3a at its upper end and its lower end. A gripping force detection sensor 9 is attached to the. The upper end of the lower rod 13b is connected to the gripping force detection sensor 9, while the lower end is provided with a gripping claw 6.

As shown in FIG. 3, the gripping force detecting sensor 9 is constructed by attaching strain gauges 9b to 9b to four quadrants of the periphery of a main body 9a in which a hollow portion 9c having a cross section having a substantially glasses shape is formed. The upper and lower surfaces of the main body 9a are mounting surfaces for the upper and lower split rods 13a and 13b, and are fixed by bolts (not shown). The main body 9a is made of a material having a certain elasticity, and is formed so that the axial deviation of the upper and lower split rods 13a and 13b can be accurately transmitted to the strain gauges 9b to 9b.

Each of the strain gauges 9b to 9b is relay-connected to a control device 50, which will be described later, so that a slight axial misalignment between the upper and lower split rods 13a and 13b can be prevented.
Is converted into an electric signal and input to the control device 50. The other gripping force detection sensors 7 and 8 have the same configuration, and the strains of the support rods 11 and 12 are converted into electric signals and input to the control device 50.

The gripping claws 4 to 6 are made of a material having an appropriate elasticity and a high friction coefficient. Among them, the gripping claws 4 and 5 sandwich the cylindrical portion of the core 40 at the right end in FIG. The gripping claw 6 is formed in a substantially hook shape so that it can be gripped by hooking the upper edge of the opening at the left end in the figure.

In FIG. 1, reference numeral 30 denotes a visual sensor, which includes a video camera and an image processing device for processing the video signal output by the video camera.
The concave-convex portion 42a of the main mold 42 is input as image information with a video camera, and the image is processed to detect the position of the main mold 42, that is, the storage position of the core 40. The position of the main mold 42 detected by the visual sensor 30 is made to be recognized by the robot 20 through the controller 70.

Reference numeral 41 is a carrier pallet for the core 40. The core 40 is transferred from the core process to the standby position while being placed on the pallet 41 and roughly positioned. Although not shown, a sensor for confirming the presence of the core 40 is installed at this standby position, and this sensor is also connected to the control device 50.

Next, the control device 50 for controlling the operation of the actuators 1 to 3 will be described.

As shown in FIG. 4, the controller 50 includes a pulse generator 51, an A / D converter 52, a program 53,
The input / output device 54 is mainly configured.

The pulse generator 51 includes the drive unit 5
5 to 57 to supply pulses to the pulse motors 1c to 3c of the actuators 1 to 3 so that each of the pulse motors 1c to 3c can be rotated by an angle or a rotation speed corresponding to the number of supplied pulses. Forward or reverse. It should be noted that each of the pulse motors 1c to 3c is individually supplied with a pulse to control the rotation angle thereof.

The A / D converter 52 is an analog amplifier 60.
Various analog signals input from the above are converted into digital signals, and the gripping force detection sensors 7 to 9 and the stroke sensors 15 to 17 of the actuators 1 to 3 are connected to the analog amplifier 60.

Referring to FIG. 5, the gripping force detecting sensor 7 will be described as an example. A strain detecting bridge circuit is constituted by two opposing resistances of the four strain gauges 7a to 7a in the gripping force detecting sensor 7. The output from the bridge circuit is input to the differential amplifier, and the strain of the support rod 11 (upper and lower split rods 11a, 11) is output from the differential amplifier.
An analog signal corresponding to the axis shift b) is output, and this analog signal is input to the A / D converter 52 described above.

Other strain gauges 8a-8a, 9a-9
The circuit a is similarly configured for a, and an analog signal corresponding to the distortion of each of the support rods 11 to 13 is input to the A / D converter 52.

The stroke sensors 15 to 17 are also connected to the analog amplifier 60, and each sensor 1
The analog signal corresponding to the stroke amount of each rod 1a to 3a detected by 5 to 17 is an analog amplifier 60.
To the A / D converter 52 after being amplified.

On the other hand, the operation signal of the robot hand 20 is
It is input to the control device 50 via the RS232C converter 71 and the input / output device 54.

The program 52 stores a core-containing flow shown by the flowcharts in FIGS. 6 and 7.
The robot hand 2 will be described below based on this flowchart.
0 and the operation of the actuators 1 to 3 will be described.

First, an instruction to insert the core is given to the robot hand 20 which is in a stopped state at the original position (this instruction is given by operating a start button (not shown) of the control device 50), whereby the robot is operated. The hand 20 is activated and a series of core-conveying flow starts.

When the robot hand 20 is activated, first, in step 1 (hereinafter abbreviated as S1; the same applies to the other steps), the core 4 on the transfer pallet 41 is formed.
Presence of 0 is confirmed. This is determined by a signal from a presence confirmation sensor (not shown) provided on the transport pallet 41. When the core 40 is not conveyed to the predetermined standby position, the main mold line is stopped, the robot hand 20 is stopped, and the core storage device is returned to the original position stopped state.

When the presence of the core 40 is confirmed, S2, S
The type and position are respectively confirmed in 3, and the robot hand 20 is operated based on this in S4, and each of the gripping claws 4 to 6 is moved to a position where the core 40 can be gripped.

When the grip claws 4 to 6 are moved to the proper positions, the core 40 is clamped in S5.
That is, first, the actuators 1 and 2 are actuated to press the gripping claws 4 and 5 against the core, so that one end of the core 40 (see FIG.
At the right end) is clamped. At this time, if one of the grasping claws 4 (or 5) comes into contact with the core 40 first, this is confirmed by the grasping force detection sensor 7 (or 8), and the other grasping claw 5 (or 4) is detected. The operation of the one gripping claw 4 (or 5) is stopped until the contact is made. When the contact between the gripping claws 4 and 5 is confirmed, the actuators 1 and 2 are actuated again, and the rods 1a and 2a move forward until the gripping force of the gripping claws 4 and 5 reaches the set value. When the gripping of the gripping claws 4 and 5 is completed, the actuator 3 is actuated next to bring the gripping claw 6 into contact with the other end (the left end in FIG. 1) of the core 40. This grip claw 6 is also pressed until it reaches a preset grip force.

In this way, when the gripping force of each of the gripping claws 4 to 6 reaches a preset value and the core 40 is gripped with a force commensurate with its strength, this is confirmed in S6. At S7, the operations of the actuators 1 to 3 are locked and the core 40 is fixed in the gripped state.
At 8, the position of the gripped core 40 is recognized. This gripping position is obtained based on the stroke amount of each rod 1a to 3a detected by the stroke sensors 15 to 17.

In S9, it is determined whether or not the robot hand 20 has recognized the gripping position of the core 40, and if so, the robot hand 20 operates in S10 to carry the core 40. In this transportation, the robot hand 20 moves the clamp device to a position above the main mold 42 by recognizing the position of the main mold 42 via the visual sensor 30 or based on a predetermined movement trajectory stored in advance by teaching. It is carried out by If the position of the core 40 has not been recognized in S9, S8 and S9 are repeated.

When the transport of the core 40 is started, it is determined in S11 whether or not the core 40 has dropped. If the core 40 drops and the gripping force of all the gripping claws 4 to 6 changes, that is, the strain of each of the support rods 11 to 13 is eliminated and the gripping force detection sensors 7 to 9 detect the gripping force. If the force becomes zero, the main mold line is stopped in S12, while the robot hand 20 is stopped, and this flow is stopped at this point due to the occurrence of trouble. That is, the subsequent flow is not executed, and the robot hand 20 or the clamp device is returned to the original position.

Next, the gripping force of each of the gripping claws 4 to 6 is maintained at a predetermined value, and the core 40 is conveyed to above the main mold 42 in a state where the core 40 is confirmed to be clamped. When,
In S13, the stationary of the main mold line is confirmed. That is, it is determined whether the main mold 42 has been conveyed to a predetermined position and the line is in a stopped state (standby state).
If the master die line is moving and the master die 42 has not reached the standby position yet, the robot hand 20 in S14.
Is stopped and put in a standby state, and the conveyance of the core 40 is interrupted until the main mold line stops.

When the clamping of the core 40 and the stillness of the main mold line are confirmed in S11 and S13, the core storing position, that is, the position of the main mold 42 is confirmed in S15, and the same position is further confirmed in S16. It is determined whether or not the robot hand 20 has confirmed. Here, the position of the main mold 42 is confirmed by the visual sensor 30, while the gripping position of the core 40 is the position of each gripping claw 4 to 6 (each rod detected by the stroke sensors 15 to 17) as described above. 1a to 3a stroke amount) and the position of the robot hand 20.
If the gripping position of 0 is displaced from the initially taught position with respect to the confirmed position of the main mold 42, S
At 17, the gripping position is corrected. This correction is performed by operating the robot hand 20.

When the gripping position of the core 40 is corrected to an appropriate position, the core 40 is lowered in S18 and S19, and the storage in the main mold 42 is started.

When the insertion of the core 40 is started, it is determined in S20 whether the core 40 has come into contact with the side wall of the main mold 42 (hereinafter referred to as "main mold wall"). This is because each supporting rod 11 to 11 detected by each gripping force detection sensor 7 to 9 when the gripped core 40 comes into contact with the main mold wall.
It is performed based on the change of the distortion of 13.

At the time when the core 40 is lowered by a certain amount, if the contact with the main mold wall is not confirmed, it is judged that the main mold does not exist on the main mold line, and the flow returns to S17. 20 rises and the core 40 is returned upward.

On the other hand, if there is a contact, the robot hand 20 is temporarily stopped in S21, and the contact direction and contact force are obtained. Based on this, the robot hand 20 operates in the correcting direction to move the core. The gripping position of 40 is corrected again. The contact direction and the contact force are obtained by determining how much each support rod 11 to 13 is distorted in which direction. If the gripping position of the core 40 is corrected and the contact force becomes zero, the flow proceeds to S2.
When the process goes to step 2, the lowering of the core 40 is restarted, and when the core 40 again comes into contact with the main mold wall, S21 is repeated to correct the gripping position.

When the core 40 is placed in the predetermined position of the main mold 42 while the gripping position is corrected in this way, the core is pressed with a constant force for this confirmation in S23.

It is judged that the core is set in the predetermined position by the core presser, and then the core 40 is unclamped in S24. This is for each actuator 1
It is performed by the rods 1a to 3a of 3 to 3 stroke in the retracting direction.

When the core 40 is unclamped, S25
Then, the final confirmation of the placement position of this core 40 is done,
In S26, it is determined whether or not this stored position is good. If the storage position is bad, the main mold line is stopped in S27.

When it is confirmed that the core 40 is stored in a good position, the flow proceeds to S28 and S29, and the robot hand 20 is moved up to move the clamp device out of the main mold 42 and is returned to the original position. Will be returned. Robot hand 20
When is returned to the original position, it is determined in S30 and S31 whether or not there is a deviation in each axis, and if there is a deviation, the correction is made in S32. If there is no deviation, the robot hand 20 and the clamp device, etc. At the original position, it is in a stopped state, and this ends the flow of core insertion.

As described above, in the core receiving device of this embodiment, the robot hand 20 is provided with the clamp device, and the gripping claws 4 to 6 in the clamp device are within a certain range by the operation of the actuators 1 to 3. Can be moved to any position, and the gripping force for that amount of movement is
Supporting rods 11 to 13 by gripping force detection sensors 7 to 9
The distortion is always detected by detecting the distortion. That is, the gripping force can be set arbitrarily, and the gripping force is detected and always held at an appropriate value.

From this fact, the core 40 during transportation
Is always gripped with an appropriate gripping force, so that the drop is prevented in advance. Further, when there is a drop, a change in the gripping force (a state where the gripping force is zero) is detected, and at that time, the robot hand 20 is stopped and the core packing process is interrupted. Time can be eliminated.

Further, when the core 40 comes into contact with the main mold wall when the core 40 is stored, the core 4 is deformed based on the distortion of the support rods 11 to 13 caused by the slight contact.
The gripping position of 0 is corrected, so that abrasion of the main mold 42 or the core 40 due to contact is prevented in advance.

Further, each of the gripping claws 4 to 6 is moved by the operation of the actuators 1 to 3 mainly composed of the pulse motor and the ball screw, and can be moved to any position within the movable range thereof. It is possible to easily deal with a dimensional error or a deviation of the standby position on the transport pallet 41. As a result, it is possible to handle different types of cores within a certain range, so that the core storage device can be made versatile, and therefore, the transfer pallets or jigs can be easily generalized. Therefore, it is possible to eliminate the work conventionally relied on by humans in a multi-purpose casting line, and to automate the work of core filling.

Although omitted in the flow chart of FIG. 6, when the gripping force of a part of the gripping claws is changed (reduction of gripping force) due to the core scraping during the transportation of the core, it is performed immediately. The gripping claw may be moved in the pressing direction in order to correct this change, and thereby the gripping force of the gripping claw is restored to an appropriate value on the spot, and the core 4
0 is always gripped with an appropriate gripping force, and the core 4
It is possible to avoid the situation of 0 drop as much as possible.

[0058]

According to the present invention, the robot hand is equipped with a clamp device that can be stopped at any position, and each gripping claw in this clamp device can be moved to any position. Since the gripping force is detected by the gripping force detection sensor and is held at an appropriate value corresponding to the strength of the core, core scraping can be prevented.

Further, since each grip claw can be moved to any position, the grip position can be adjusted. From this, it is possible to deal with the dimensional error of the core, and further, it is possible to grip different kinds of cores with an appropriate gripping force. Therefore, the versatility of the core delivery device is enhanced, and it becomes possible to automate the core delivery work in a versatile casting line.

[Brief description of drawings]

FIG. 1 is a front view mainly of a clamp device in a core housing device according to an embodiment of the present invention.

FIG. 2 is likewise a side view of the clamp device.

FIG. 3 is a detailed view of a gripping force detection means.

FIG. 4 is a control block diagram of the core receiving device.

FIG. 5 is a circuit diagram of an analog amplifier.

FIG. 6 is a first half portion of a flowchart showing the operation of the core feeding device.

FIG. 7 is the latter half of the flowchart showing the operation of the core delivery device.

[Explanation of symbols]

 1 to 3 ... Actuator 4 to 6 ... Gripping claw 7 to 9 ... Gripping force detection device 10 ... Base 11 to 13 ... Support rod 15 to 17 ... Stroke sensor 20 ... Robot hand 30 ... Visual sensor 40 ... Core 41 ... Conveyance pallet 42 ... Main mold 50 ... Control device 60 ... Analog amplifier 70 ... Robot controller

Front page continued (72) Inventor Shuichi Nakata 1-1 Asahi-cho, Kariya city, Aichi Toyota Koki Co., Ltd. Within

Claims (1)

[Claims] 1. An actuator provided on a robot hand, capable of stopping operation at an arbitrary position, a grip claw attached to the actuator via a grip force detection sensor, and the grip force detected by the grip force detection sensor. And a control device for controlling the operation of the actuator based on the gripping force of the gripping claws.