JPH09225772A - Origin and overrun detecting device in machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an origin limit switch and an overrun limit switch arranged in a plane with a common dog, respectively, by forming the dog in such a manner that one end on the side for operating each detecting sensor has a stepped form having flat parts differed in height. SOLUTION: A dog 2 is formed by forming one metal plate in such a manner that one end on the side for operating each detecting sensor LsY, Ls+Y has a two-stage stepped form having flat parts differed in height. The overrun limit switch Ls+Y is set in a position higher than the origin limit switch LsY. Thus, the higher part 2a of the dog 2 operates the origin limit switch LsY, and the lower part 2b of the dog operates the overrun limit switch LsY.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool origin and overrun detection device for detecting the origin and movement range of a table or the like.

[0002]

2. Description of the Related Art Conventionally, in a machine tool in which a table or the like is driven by a motor under the control of a numerical controller, a rotary encoder is often provided in the motor in order to detect the amount of movement of the table. Here, the rotary encoder is roughly classified into an absolute encoder and an incremental encoder, but it is mainstream to use the incremental encoder because of its low cost and high resolution.

Since the incremental encoder only outputs pulses by rotation, a counter for counting the pulses is separately provided, and the rotation angle is recognized by referring to the counter. For this reason, this counter must be initialized before it is automatically operated in the machine tool, and such a process is generally called "origin return".

Conventionally, in order to carry out the origin return processing, a dog for detecting that it is in the vicinity of the origin and a dog for detecting that it is at the movement limit are respectively provided in the table, and the numerical controller is provided with the dog. Has taken a method of monitoring the output of a limit switch that detects that the vehicle is in a predetermined position and performing a predetermined process.

FIG. 3 is an overall view of a machine tool that returns to the origin by a conventional procedure.

In this machine tool, a column base 102 is provided on a base 101 slidably in a lateral direction (X-axis direction), and a column 103 is slidable on the column base 102 in a front-back direction (Y-axis direction). Further, a spindle head 104 is mounted on the column 103 so as to be slidable in the vertical direction (Z-axis direction). The column base 102 is driven by an X-axis motor 105, the column 103 is driven by a Y-axis motor 106, and the spindle head 104 is driven by a Z-axis motor 107. The spindle head 104 is provided with a spindle 109 that is driven to rotate by a spindle motor 108, and is equipped with a rotary magazine type automatic tool changer 110.

A fixed table 113 is fixed to the table portion 112 on the front side of the base 101. On the mounting plate 115 on the back surface of the fixed table 113, overrun limit switches Ls-X and Ls + for restricting the overrun of the column base 102 in the X-axis direction.
X and the origin limit switch LsX are arranged.

An origin dog 118 corresponding to the origin limit switch LsX and the overrun limit switch Ls-X and a dog 117 corresponding to the overrun limit switch Ls + X are fixed to the center of the front surface of the column base 102. The origin limit switch LsX,
The overrun limit switch Ls + X is fixed so that the arrangement position is different in the Z-axis direction, and the origin limit switch LsX is made lower. With this configuration, even when the column 103 moves to the right in FIG. 3 when returning to the origin, the dog 117 does not operate the origin limit switch LsX.

Regarding the Y axis, in FIG. 4, the column 1 is attached to the upper surface of the right end portion of the column base 102.
03 overrun limit switch Ls + Y that controls overrun in the + Y axis direction and origin limit switch L
sY is fixed, and the column 1
The overrun limit switch Ls-Y for controlling the overrun of 03 in the -Y axis direction is fixed. The X
Similar to the axis, the origin limit switch LsY is fixed to be lower than the overrun limit switch Ls + Y. Further, at the left end of the column 103, an origin dog 19 corresponding to the origin limit switch LsY and the overrun limit switch Ls-Y and a dog 11 corresponding to the overrun limit switch Ls + Y.
6 are fixed.

Further, an overrun limit switch Ls for controlling overrun of the spindle head 104 in the Z-axis direction.
-Z and Ls + Z are arranged on the right side surface of the column 103, and the origin limit switch LsZ is arranged below the overrun limit switch Ls + Z. The dog 120 corresponding to each of the limit switches Ls-Z and Ls + Z and the origin limit switch LsZ is attached to the spindle head 10.
It is fixed to 4.

The origin return processing of the X-axis motor 105 of the machine tool thus constructed will be described.

When an origin return command key (not shown) is pressed, the X-axis motor 105 rotates in one direction so that the column 103 moves to the right in FIG. Then
The origin dog 118 turns on the origin limit switch LsX. Further, when the X-axis motor 105 is rotated in the same direction, the origin dog 118 is located on the right side of the origin limit switch LsX in FIG. 3, and the origin limit switch LsX changes from on to off. After the origin limit switch LsX is switched from ON to OFF, first X
The origin is the point where the Z signal of the shaft motor 105 is input,
The movement of the X-axis motor 105 is stopped and a counter (not shown) is initialized. Similarly, the same applies to the Y-axis motor 106 and the Z-axis motor 107. After the origin of each axis is determined in this way, automatic operation can be performed by a control device (not shown).

If the column 103, the spindle head 104, and the column base 102 collide with a mechanical stopper (not shown) at a high speed beyond the moving range, the machine will be damaged. A switch is provided. When each of the overrun switches is turned on by each dog, the X, Y, Z axis motors 105, 106, 107 are turned off.

Therefore, each dog is connected to the column 10
3. Once the origins of the column base 102 and the spindle head 104 have been determined, there is no need to move any further, so the overrun limit switch is arranged so that overrun can be detected immediately.

Further, the time required to return to the origin depends on the length of the origin dog. In recent years, improvements in motor performance have made it possible to reduce the length of the origin dog.

On the other hand, since the origin dog and the dog are used for the same purpose of turning on and off the limit switch, it has been desired to detect the origin limit switch and the overrun limit switch with one dog.

As described above, in order to shorten the origin dog and to detect the overrun so as not to move much after the origin is determined by one dog, the overrun limit switch is used. Had to be placed near the origin limit switch.

[0018]

However, each limit switch is larger than the optical sensor. Therefore, when the overrun limit switch is planarly arranged in the vicinity of the origin limit switch, each limit switch interferes and cannot be attached.

In order to solve this problem, a method of forming dogs three-dimensionally and arranging limit switches in parallel can be considered, but there is a problem that the dog shape becomes complicated and the cost becomes high. there were.

The present invention has been made in order to solve the above-mentioned problems, and is a work capable of detecting the origin limit switch and the overrun limit switch arranged in a plane by one dog. An object is to provide a machine origin and overrun detection device.

[0021]

In order to achieve this object, an origin and overrun detection device in a machine tool according to claim 1 is provided with a origin of the movable body provided on a movable body or a fixed body of the machine tool. Origin detection sensor for detecting
An overrun detection sensor provided on the moving body or the fixed body for detecting an overrun of the moving body; and a dog for operating each detection sensor provided on the fixed body or the moving body. In particular,
The origin detection sensor and the overrun detection sensor are fixed to the moving body or the fixed body with a height difference, and the dog is provided with a flat portion having different heights at one end on the side where each detection sensor is operated. It is formed to have a two-step staircase. Therefore, it is possible to detect the origin and the overrun with one dog by causing the high portion of the dog to operate the origin detection sensor and the low portion of the dog to operate the overrun detection sensor.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a machine tool using the origin and overrun detection device of the present invention will be described below.
This will be described with reference to the drawings.

FIG. 1 is an enlarged view of the origin and overrun detecting device, and FIG. 2 is a front view of the essential parts when the origin and overrun detecting device is attached to a machine tool.

Since the machine tool of the present embodiment is the same as the conventional machine tool, the description of its construction is omitted and the same members as those in FIG. 3 are designated by the same reference numerals. In addition, the origin and overrun detection device are installed in the column base 10
Only the state (Y axis direction) attached to No. 2 will be described.

In FIG. 2, the dog 2 is fixed to the lower end of the column 103, and the mounting plate 5 is fixed to the right end of the column base 102. A mounting plate 6 having an overrun limit switch Ls-Y is fixed to the left side of the mounting plate 5. A cover 10 for protecting the sliding portion of the column base 102 is attached below the column base 102. Further, below the column 103, a cover 11 for attaching the sliding portion of the column 103 to the dust is attached.

Origin and overrun detection device 1 of the present invention
1, as shown in FIG. 1, the dog 2, the origin limit switch LsY, and the overrun limit switch L
It is composed of s + Y.

The dog 2 has a two-step staircase in which one end of one metal plate on which each of the detection sensors is operated has a flat portion of different height (higher one is 2a and lower one is 2b). Formed to have a shape.

The mounting plate 5 is formed in the shape of a metal plate, and the limit switches are mounted in a plane. Regarding the arrangement position of each of the limit switches, the overrun limit switch Ls + Y is located higher than the origin limit switch LsY.
Therefore, the dog 2b is the overrun limit switch Ls.
Corresponding to + Y, dog 2a is origin limit switch LsY
Corresponding to

Next, the operation of the origin and overrun detection device 1 in the machine tool of this embodiment will be described.

When an origin return command key (not shown) is pressed, the Y-axis motor 106 rotates in one direction so that the column 103 moves to the right in FIG. Then, the origin dog 2b first passes through the origin limit switch LsY. At this time, since the origin limit switch LsY is fixed at a low position and the origin dog 2b is low, the origin limit switch LsY does not operate. Furthermore,
When the column 103 moves to the right, the origin dog 2a comes into contact with the origin limit switch LsY. After that, when the column 103 moves to the right, the origin dog 2 passes through the origin limit switch LsY. Origin limit switch LsY
From the ON state to the OFF state, the Y point is the origin of the point where the Z signal of the Y-axis motor 106 is input.
The shaft motor 106 is stopped.

Next, when the column 103 is moved to the right in FIG. 1 by a Y-axis movement key (not shown), the dog 2b comes into contact with the overrun limit switch Ls + Y, and the overrun limit switch Ls + Y is activated,
The column 103 cannot be moved.

As is apparent from the above description, in the origin and overrun detecting device 1 in the machine tool of the present embodiment, the dog 2 is formed in a two-step staircase shape having flat portions of different heights, and Since the higher part 2a of the dog 2 operates the origin limit switch LsY and the lower part 2b of the dog operates the overrun limit switch Ls + Y, the origin limit arranged in a plane with one dog is used. The switch LsY and the overrun limit switch Ls + Y can be detected, and the entire machine tool can be downsized.

In the origin and overrun detecting device in the machine tool of this embodiment, the dog 2 is attached to the column 1
03, the limit switches LsY and Ls + Y are fixed to the column base 102 side, but the dog 2 is fixed to the column base 102 side and the limit switches LsY and Ls + Y are fixed.
May be fixed to the column 103 side.

Although the limit switches LsY and Ls + Y are used as the origin detection sensor and the overrun detection sensor, they may be composed of a light emitting element and a light receiving element. Further, a magnetic sensor may be used.

Further, in the origin and overrun detecting device in the machine tool of this embodiment, the high portion 2 of the dog 2 is used.
a corresponds to the origin limit switch LsY, and the low portion 2b of the dog 2 corresponds to the overrun limit switch Ls + Y, but conversely, the high portion 2a of the dog 2 corresponds to the overrun limit switch Ls + Y. However, the lower part 2b of the dog 2 has the origin limit switch L
It may be configured to correspond to sY.

Further, as the machine tool of this embodiment, a machining center capable of exchanging tools is used, but it may be used for other machine tools. For example, a wire cut electric discharge machine, a robot or the like may be used.

[0037]

As is apparent from the above description, the origin and overrun detecting device in the machine tool according to claim 1 forms the dog in a two-step stair shape having flat portions of different heights, Since the high part of the dog operates the origin detection sensor and the low part of the dog operates the overrun detection sensor, the origin detection sensor and the overrun arranged in a plane with one dog are used. A detection sensor can be detected.

[Brief description of drawings]

FIG. 1 is an enlarged view of an origin and overrun detection device of a machine tool according to this embodiment.

FIG. 2 is a partial side view when the origin and overrun detection device of the machine tool according to the present embodiment is used for a column.

FIG. 3 is a front view showing the overall configuration of a conventional machine tool.

FIG. 4 is a side view showing the overall configuration of a conventional machine tool.

[Explanation of symbols]

 1 Origin and overrun detector 2 Dog 5 Holding plate 102 Column base 103 Column LsY Origin limit switch Ls + Y Overrun limit switch Ls-Y Overrun limit switch

Claims (1)

[Claims] 1. An origin detection sensor for detecting an origin of the moving body provided on a moving body or a fixed body of a machine tool and an overrun of the moving body provided on the moving body or the fixed body. An origin and overrun detection device in a machine tool comprising an overrun detection sensor and a dog that operates each of the detection sensors provided in the fixed body or the movable body, wherein the origin detection sensor and the overrun detection sensor And are fixed to the movable body or the fixed body with a height difference, and the dog has a two-step staircase shape having a flat portion having different heights at one end on the side where the respective detection sensors are operated. The high part of the dog activates the origin detection sensor,
An origin and overrun detection device in a machine tool, wherein a lower portion of the dog operates the overrun detection sensor.