JPH0957581A - Life detector for tool gripper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a life detector which prevents beforehand tool holding failure caused by abrasion of a resin-made integrated tool gripper for holding a tool of a machining center. SOLUTION: A measuring arm 6 having two arms is provided inside an upper tool gripper 3 of a disk 2 of a tool magazine 1 in such a state as advancing to a measurement position (a) by a cylinder 11. Conductive rubbers 9A, 9B are stuck opposed to each other to the end of the two arms, the outside of the holding part of the tool gripper 3 for holding a tool which is divided by advancement to the measurement position (a) is surrounded with the conductive rubbers as sandwiching it, and when the conductive rubbers are compressed outside of the tool holding part by exceeding a prescribed compression ratio so as to become conductors, they are judged to have life in an NC device. When the compression quantity is less than a prescribed compression ratio, they are still nonconductors so that they are judged to have no life in the NC device and the life display is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the life of a tool gripper for holding a tool of an automatic tool changing device for a machine tool such as a machining center due to long-term use.

[0002]

2. Description of the Related Art For example, a machining center as shown in FIG. 7 stores a plurality of tools T in a magazine 101 in a state of being gripped by a tool gripper, and exchanges them with a spindle 102 as needed. There is. Conventionally, this type of tool gripper has two gripping claws 103a, 103 as shown in FIG.
The metal tool gripper 103 formed by combining b is used, but recently, an integrated tool gripper 104 made of resin as shown in FIG. 9 has been used.

[0003]

The resin-made integral tool gripper 104 described in the prior art has a contact portion with the tool holder, especially a tool grip portion that rubs against the tool holder when the tool is attached and detached, as compared with the metal gripper 103. The inside of is easily worn.
Therefore, as the wear of the tool gripper progresses, the tool gripping force gradually decreases, and the held tool tilts or its vertical position shifts significantly. Such misalignment of the tool has a problem that it interferes with the approaching spindle for tool exchange and damages the spindle or the magazine, or the tool cannot be handed over and the tool falls. There is.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a device for detecting the life of the integrated gripper, that is, the replacement time. is there.

[0005]

A gripper life detecting device of the present invention is a device for detecting a life due to wear of a tool gripping part of a tool holding tool gripper of a machine tool having an automatic tool changing function, and measuring the same. A movable measurement arm having two arms surrounding the outside of the tool gripping portion of the tool gripper holding the tool indexed to the position so as to be sandwiched by the tips, and the measurement arm at the standby position and the measurement The driving means for positioning the position and the measuring arm are attached to the inside of the two arms of the measuring arm so as to face each other and are electrically insulated from each other. And a means for detecting the life of the tool gripper by the change of the conductive rubber from the non-conductive body to the conductive body, and the tool gripper of the tool gripper holding the tool. Which detects the amount of deflection changes due to wear of a non-conductive material of the conductive rubber by a change in the electrical conductor.

In the tool life detecting device for an integrated tool gripper configured as described above, the measuring arm advances toward the tool gripper that holds the tool indexed at the set measuring position, and the two arms are provided. Sandwich the outside of the tool gripper of the tool gripper with. At this time, if the conductive rubber comes into contact with the outside of the tool gripping portion of the tool gripper and is compressed beyond a certain compression ratio, it is determined that it has become a conductor and has a life. Also,
When it is separated from the outside of the tool gripping portion or when it does not reach a certain compression ratio, it remains a non-conductive body, and it is determined that the life has expired and a signal and an indication are output. Therefore, the integrated tool gripper is no longer used until it cannot be used, and accidents when the tool is attached or detached can be prevented.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a tool magazine having a gripper life detecting device of the present invention, FIG.
Is a side view of the gripper life detecting device, and (b) is a top view.

In FIGS. 1 and 2, an integrated tool gripper made of resin is provided at equal intervals on the outer peripheral portion of a disc 2 which is supported by a magazine frame 4 fixed to a bed (not shown) in the tool magazine 1 so as to be rotatable in a horizontal plane. 3 is attached in a radial state with the tool grip 3a facing outward. The disc 2 is rotated and indexed by a servo motor (not shown), and the tool gripper 3 holding the tool is indexed to the measurement position a.

The measuring arm 6 of the gripper life detecting device 5 is formed in a U shape in which two parallel arms 6a and 6b project, and is formed on the upper end of the magazine frame 4 projecting upward from the central hole of the disc 2. The support arm 7 is attached to the tip of the piston rod 11a of the hydraulic or pneumatic fluid pressure cylinder 11 to be fixed.
Is fixed through. Then, the measurement arm 6 is moved forward and backward in the radial direction on the disk 2 through which the two protruding arms 6a and 6b pass through the measurement position a, so that the measurement arm 6 is positioned at the standby position at the backward end and the measurement position a at the forward end. The measuring arm 6 always stands by at the retracted end position, and after indexing the magazine, the measuring arm 6 advances to the measuring position a to project the two protruding arms 6.
a and 6b surround the tool gripper 3 holding the tool T so as to sandwich the outside of the tool gripping portion 3a. The measuring position a is set to a position different from the tool changing position at the time of automatic tool changing, but may be the same as the tool changing device.

Conductive rubbers 9A and 9A are provided inside the tips of the two arms 6a and 6b via a hard insulator 8 such as resin or rubber.
Two Bs are attached to each other. The conductive rubbers 9A and 9B are non-conductive (insulating) soft rubbers mixed with powders of conductive materials such as metal or carbon so that they do not usually come into contact with each other, and flexible conductive coatings 9a are attached to both surfaces. Has been done. When the conductive rubbers 9A and 9B are compressed by an external pressure to exceed a certain compression ratio, the mixed conductive materials come into contact with each other to become a conductor. Further, when the external pressure is removed and the shape returns to the original shape, the non-conductor has a relatively high electrical insulation resistance value.

FIG. 3 is an electric circuit diagram of this apparatus. Reference numeral 12 is a switch that is turned on when the advance of the piston rod of the fluid pressure cylinder 11 is completed and is turned off before it is retracted, and 13 is a power supply. Therefore, when the conductive rubbers 9A and 9B are compressed beyond a certain compression ratio and suddenly change from a non-conductive body to a conductive body, the voltage of the power source 13 is applied to the NC device 14, and the life of the NC device 14 is reduced to O.
Judged as K. In addition, the power supply voltage does not reach the constant compression ratio and remains the specific conductor, and the power supply voltage is NC within the timer setting time (not shown).
When the voltage is not applied to the device 14, it is determined that there is no life in the NC device 14, and the display device (not shown) indicates that no life has been reached. In addition, it is possible to notify the operator of the necessity of gripper replacement by means of an indicator light such as a patrol lamp or a buzzer.

FIG. 4A is a graph showing the relationship between the amount of flexure δ of the gripper 3 when holding the tool and the tool gripping force.
(B) is a graph showing the relationship between the amount of flexure δ of the gripper 3 when the tool is held (the amount of flexure of the conductive rubbers 9A and 9B) and the change in the electrical resistance value of the conductive rubber. As shown in this graph, the tool gripping force of the tool gripper 3, that is, the force for pulling out the tool, is increased as the bending of the tool gripper of the tool gripper is increased, so that a large holding force is generated. Therefore, when the contact portion of the tool grip 3a with the tool T is worn due to long-term use, the flexure amount δ decreases, and the amount of compression of the conductive rubbers 9A and 9B also decreases. Therefore, if the compression ratio is set so that the conductive rubbers 9A and 9B change from a non-conductive body to a conductive body with the amount of flexure (permissible value) in a worn state, which is the limit of the life of the gripper 3, the electric power of FIG. It is possible to identify and display the life of the circuit.

Next, the detecting operation of the life detecting device configured as described above will be described with reference to the flowchart of FIG. In step S1, the tool gripper 3 is indexed to the set measurement position a, and it is confirmed whether or not the tool gripper 3 indexed to the measurement position a in step S2 has the tool T. And in case of NO, it becomes END,
In the case of YES, in step S3, the measurement arm 6 at the standby position advances to the measurement position a and surrounds the outside of the tool gripper 3a of the tool gripper with the two arms 6a as shown in FIG. Next, in step S4, the switch 12 is turned off when the advancement of the measurement arm 6 to the measurement position a is completed.
N, the detection circuit becomes operable, and at the same time, a timer (not shown) in the NC device 14 starts counting.

Next, in step S5, it is confirmed whether or not the conductive rubbers 9A and 9B are conductors, and FIG.
As shown in, when the conductive rubbers 9A and 9B are separated from the outside of the tool gripping portion 3a of the tool gripper 3 or are in contact with each other but have not reached a certain compression ratio, the non-conductive body remains NO, so In S6, the NC device 1
If no signal is input even if the timer counts out within 4, it is judged that the life has expired, and the life is displayed.
Further, in step S5, as shown in FIG. 6B, if the conductive rubbers 9A and 9B have been compressed to exceed a certain compression ratio and changed into conductors, YES is given and a signal is input to the NC device 14 and there is a life. Is judged.

Then, in step S7, the switch 12 is turned off by the count-out of the timer to disconnect the electric circuit, and in step S8, the measuring arm 6 is retracted to the standby position and one cycle is completed. Note that the conductivity of the two arms 6a of the measuring arm 6 facing each other can be coped with when the material of the tool gripper 3, the displacement characteristics associated therewith, or the shape, size, etc. of the tool gripper 3 are changed. An adjusting mechanism capable of changing the distance between the rubbers 9A and 9B may be provided.

[0016]

Since the present invention is configured as described above, it has the following effects. After indexing the magazine, move the measuring arm with the conductive rubber attached to the tips of the two arms to the measuring position, and place the outside of the tool gripper of the tool gripper that holds the tool indexed at the measuring position. Enclosed with a book arm, the change in the amount of bending due to wear on the outside of the tool grip is detected by using the change from non-conductor to conductor with conductive rubber, and the life of the integrated tool gripper is displayed. As a result, the correct posture of the tool inside the gripper is maintained, there is no misalignment, tilt, etc., and it is possible to avoid problems such as damage to the spindle or magazine when changing the tool, drop of the tool, etc. You can

[Brief description of drawings]

FIG. 1 is a perspective view of a tool magazine including a life detecting device according to the present invention.

FIG. 2A is a side view of a tool gripper life detection device,
(B) is a top view.

FIG. 3 is an electric circuit diagram of the life detecting device.

FIG. 4A is a graph showing the relationship between the tool gripper bending amount and the tool gripping force, and FIG. 4B is the tool gripper bending amount (the bending amount of the conductive rubber) and the resistance value of the conductive rubber. It is a figure which shows the relationship with the change of.

FIG. 5 is a flowchart of a life detection operation of the tool gripper.

FIG. 6 is an explanatory diagram of a life detecting operation of the measuring arm and the tool gripper, (a) shows a state when there is no life, (b)
FIG. 4 is a diagram showing a state when there is a life.

FIG. 7 is a perspective view of a conventional machining center for explaining the technology.

FIG. 8 is a perspective view of a magazine having a metal tool gripper for explaining the related art.

FIG. 9 is a perspective view of a magazine having a resin-made integral tool gripper for the same technical description.

[Explanation of symbols]

 1 Tool Magazine 3 Tool Gripper 3a Tool Grip 5 Gripper Life Detecting Device 6 Measuring Arm 6a Two Arms 9A, 9B Conductive Rubber 11 Fluid Cylinder 14 NC Device 15 Spindle T Tool

Claims (1)

[Claims] 1. A device for detecting the life of a tool holding tool gripper of a machine tool having an automatic tool changing function due to wear of a tool gripping part, the tool gripper holding a tool indexed at a measurement position. Of the tool holding portion, which has two arms surrounding the outside of the tool gripping portion so as to be sandwiched between the tip ends thereof, a movable and retractable measuring arm, a driving means for positioning the measuring arm between a standby position and the measuring position, and two measuring arms. A conductive rubber that is attached to the inside of the arm of the book facing each other in an electrically insulated state and suddenly changes from a non-conductive body to a conductive body when compressed beyond a certain compression ratio; Means for detecting the life of the tool gripper by changing the rubber from the non-conductive body to the conductive body, and the change in the deflection amount due to wear of the tool gripping part of the tool gripper holding the tool Body A tool gripper life detection device, which detects by changing from a conductor to a conductor.