JPH11337325A - Method and device for controlling move of measurement head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a measurement head from moving in a direction other than the measurement direction of a measurement head due to program mistakes and electrical noises by positioning the measurement head at a measurement position while power feed to a drive motor that is in charge of a move in a direction that orthogonally crosses the measurement direction is interrupted. SOLUTION: Before a measurement head 20 starts entering a measurement hole H from a measurement preparation position P2 located outside the axial direction of a measurement hole H, the supply of power to drive motors Mx and My for X and Y axes is turned off, and power supply to the drive motors Mx and My for X and Y axes is turned on after the measurement head 20 has returned to the measurement preparation position P2 again. During this period, the motors Mx and My do not rotate, even if a program regarding the move in the direction of X and Y axes exists in the traveling program of the measurement head 20 which is inputted to a control device in advance or an external electrical noise operates on the control device for causing X and Y operations to run out of control, thus preventing the measurement head 20 from colliding against the inner wall of the measurement hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for moving a workpiece and a measuring head relative to each other in three orthogonal directions perpendicular to each other, and positioning the measuring head at a measurement preparation position facing a portion to be measured of the workpiece. More particularly, the present invention relates to a technology for permitting only the axial movement of the measurement head and completely locking the other movement directions when the measurement head is in a measurement state.

[0002]

2. Description of the Related Art As a conventional measuring apparatus, there is one disclosed in Utility Model Registration No. 2549430. According to this, a plurality of measuring heads are selectively set in a standby position and a measurement position protruding axially forward from a moving head that moves in three axial directions orthogonal to each other, that is, in the left and right, front and rear, and vertical directions. It is provided so as to be movable, and is inserted into a hole to be measured of a workpiece in a state where one of the measuring heads protrudes to a measurement position to measure the hole diameter. Also, a plurality of quill spindles are provided on an elevating frame that moves left and right and up and down so as to move in the axial direction (front-back direction) (Japanese Patent Laid-Open No. 55-85).
No. 202) or a tool that measures by attaching a measuring head to a spindle by a tool changing function (Japanese Patent Laid-Open No. 52-58179).
Etc. are also known. In such a measuring device, the measuring head is rapidly moved in two axes directions other than the axial direction (measuring direction) of the measuring head to make the hole coordinates to be measured coincide with the measuring head. Move it,
Fast-forward to the measurement preparation position, which is axially opposed to the entrance of the hole to be measured, or rapidly control the three axes simultaneously to the measurement preparation position, and then slowly feed the measurement head in its axial direction. Then, the measuring head is moved into the hole to be measured, and is moved in the axial direction or stopped at a predetermined axial position to measure the hole diameter at a desired axial position.

[0003]

In the above measuring apparatus, the three axes are electrically controlled by a program, and the measuring head is positioned at the measurement preparation position, and thereafter, enters the hole to be measured in the axial direction. Conventionally, since the above-described control is performed in a state where power is supplied to three drive motors for driving the three axes, a program error or an electrical noise to an electrical control system that executes the program is performed. Due to the unexpected factor described above, while the measuring head is located in the hole to be measured, there is a possibility that the measuring head may move in one of two other directions except for the axial direction of the measuring head. If such a malfunction occurs, there is a problem that the measuring head collides with the inside of the hole and the measuring head is damaged, so that the subsequent measuring operation cannot be performed. The object of the present invention is to
If the measuring head moves in a movement direction other than the measurement direction, the measurement head will move in a direction other than the measurement direction even if there is a program error or electrical noise when the measurement head is in a position that causes damage due to interference with the workpiece. To avoid moving to Another object of the present invention is to provide a mechanism for more securely locking the movement of the measuring head in the direction of gravity. Still another problem is that when there is a plurality of locations to be measured, when moving from one measurement to the next, moving in the measurement direction causes the measurement head to move in the axial direction while the measurement head interferes with the workpiece. It is an object of the present invention to provide a mechanism which can be completely locked to prevent the measuring head from advancing in the axial direction and interfering with a workpiece due to a programming error or electric noise.

[0004]

In order to solve the above-mentioned problems, in the present application, a measuring head moves relative to a workpiece in a measuring direction and an operation in a direction perpendicular to the measuring direction, so that the measuring head is moved to a measured portion of the workpiece. In a measuring device that moves from a confronting measurement preparation position in the measurement direction to a measurement position for measuring a location to be measured, in a state where power supply to a drive motor that controls movement in a direction orthogonal to the measurement direction is cut off, measurement is performed. The head is positioned at a measurement position (claim 1). According to this, while the measurement head moves from the measurement preparation position to the measurement position, no power is supplied to the drive motor that controls the movement in the direction perpendicular to the measurement direction. Even if it enters, it will never work,
The measurement head can be prevented from moving in the orthogonal direction.

Further, in the present application, the measuring head is moved relative to the workpiece by movement in the axial direction and movement in a direction perpendicular thereto, and the hole to be measured and the measuring head formed in the workpiece are defined by the holes. After the measurement head is moved in the axial direction of the hole after being confronted in the axial direction, the measuring device enters the inside of the hole to reach the measurement position. When the measuring head is located in the hole, it is orthogonal to the hole axis direction. The power supply to the drive motor that controls the movement in the orthogonal axis direction is cut off (claim 2). According to this, while the measuring head is located in the hole, power is not supplied to the drive motor that controls the movement in the orthogonal axis direction orthogonal to the hole axis direction. Does not operate even if the gas enters, the measuring head is prevented from moving in the orthogonal direction, and the measuring head can be prevented from colliding with the inside of the hole and being damaged.

In the apparatus of the present invention, the measurement head and the measurement head face each other by moving the measurement head and the measurement head relative to each other in at least two orthogonal directions orthogonal to the axial direction of the measurement head. Two drive motors for moving in the orthogonal two-axis directions in a measuring device which is positioned at a measurement preparation position, and from which the measurement head moves relative to the measured position in the axial direction to reach the measurement position. An electric opening / closing means is interposed in the middle of the power line, and the electric opening / closing means is used while the measuring head returns to the measurement preparation position from the start of the axial movement from the measurement preparation position to the measurement position.
It is open (claim 3). According to this, power is not supplied to the drive motor that moves in two directions orthogonal to the axial movement of the measurement head until the measurement head moves in the axial direction from the measurement preparation position and returns to the measurement preparation position again. .

[0007] Further, the measuring head is provided so as to be movable in three axial directions including the axial direction of the measuring head and orthogonal to each other, a driving motor for moving the measuring head in each of the axial directions, and controlling each driving motor. A measuring device comprising a motor drive unit and a measuring head for moving a measuring head in an axial direction to reach a measuring position after a measuring head is opposed to a measuring preparation position facing a measured portion of a workpiece. A drive motor that moves in two orthogonal directions except the above and a corresponding motor drive unit are connected via an electromagnetic contactor, and the electromagnetic contactor is provided with opening and closing command means for opening and closing based on position information of the measuring head. (Claim 4). According to this, the arrival of the measurement head at the measurement preparation position is detected based on its position information, for example, based on the rotation amount of the drive motor, whereby the remaining orthogonal biaxial movement except the axial direction of the measurement head is detected. When the electromagnetic contactor for the drive motor to be performed is opened to cut off the power supply to the two drive motors, the measurement head is moved in the axial direction while the state is maintained, and the measurement is performed. Close the magnetic contactor. Specifically, the drive motor is a servomotor, and the opening / closing command means checks that the measurement head has reached the measurement preparation position based on the position information of the measurement head. Is turned off (claim 5). The measuring head measures the inner diameter of the hole (claim 8).

The axial direction of the measuring head is the horizontal axis direction, and two orthogonal axes of the left and right axes are the left and right axes and the vertical axis.
It is preferable that the brake is operated together with the FF (claim 6). According to this, since the brake is applied to the vertical axis, even if an attempt is made to move downward due to gravity, this can be prevented, and the vertical axial movement can be more reliably prevented. Further, in the present application, a measuring head provided so as to be movable in three axial directions including the axial direction of the measuring head and orthogonal to each other, a driving motor for moving the measuring head in each of the axial directions, and a motor drive unit for controlling each driving motor A measuring device that moves the measuring head in the axial direction to reach the measuring position after the measuring head is opposed to the measurement preparation position facing the measured portion of the workpiece. An open / close command means for connecting the drive motor to be performed and the corresponding motor drive unit via an electromagnetic contactor, and for opening and closing the electromagnetic contactor based on position information of the measuring head is provided. In this configuration, in addition to the operation of claim 4, for example, one of a plurality of measured locations
When moving from the location to the next measurement location, with the power supply to the drive motor performing axial movement of the measurement head turned off, the movement can be performed by the remaining orthogonal two-axis control,
It is possible to prevent the measuring head from moving in the axial direction and interfering with the workpiece during the movement from the measuring point to the next measuring point due to a program error or the like.

[0009]

1, a pair of left and right guide rails 2 are provided on a bed 1 and extend in the front-rear direction.
A guide member 3 is linearly guided on the guide rail 2, and the guide member 3 is integrally fixed to a lower surface of a front-rear movement base 4. The forward / backward movement base 4 rotates the feed screw shaft 6 of the Z-axis (front-rear direction) feed screw mechanism 5 by a Z-axis drive motor (Z-axis motor) Mz, so that the measurement direction (axial direction of the measurement head; In the Z-axis direction). The movable base 4 is provided with a pair of front and rear left and right guide rails 7.
A column 9 is connected to the left and right guide rails 7 via a guide member 8.
Are movably guided in the left-right (X-axis) direction. The column 9 moves in the left-right direction when the X-axis feed screw shaft 11 of the X-axis feed screw mechanism 10 is rotated by the X-axis drive motor (X-axis motor) Mx. In column 9,
The lifting head 12 is moved by a vertical guide rail (not shown).
Are movably guided in the vertical (Y-axis) direction. The lifting head 12 is driven by a Y-axis drive motor (Y-axis motor) My attached to the column 9 to rotate the Y-axis feed screw mechanism 13 in the Y-axis direction.
The shaft feed screw shaft 14 is moved up and down by being rotated. A measuring head 20 for measuring the inner diameter is attached to the tip of the elevating head 12. The measuring head 20 is an open / close arm type electric micrometer disclosed in Utility Model Registration No. 2549430, as well as Japanese Patent Application Laid-Open No. 55-85202.
And a bore gauge comprising the air micrometer disclosed in the above-mentioned publication. A work table 21 is provided on the bed 1 in front of the column 9, and a workpiece (measurement target: work) W is held on the work table 21 by a clamp mechanism (not shown).

Each drive motor Mx, M for X, Y, Z axes
y and Mz are servo motors, respectively, and control means 30 for controlling them is housed in a control box 29.
The control means 30 includes a control device (NC control device) 31 and a motor drive unit 32. The control device 31 executes a control program described later to exchange various kinds of information with the motor drive unit 32, controls the movement of the measuring head 20 by moving the X, Y, and Z axes, and controls the motor drive unit 32. Relay contacts MCx1-3, MCy1-3, MCz included in
A control unit 33 that controls the relays (electromagnetic contactors: electric switching means) MCx, MCy, and MCz that control the opening and closing of 1-3.
And a storage section 34 for storing the control program and for storing the measured values from the measuring head 20.
The motor drive unit 32 includes the three drive motors Mx and Mx.
Servo drive units (motor drive units) Svx, Svy, and Svz for controlling y and Mz are provided. Servo drive units Svx, Svy, Sv
z and the corresponding drive motors Mx, My, and Mz are located on the three-phase power line 35 connecting them, one for each of the three phases.
Each relay contact MCx1-3, MCy1-3, MC
z1-3 is interposed. Each drive motor Mx, My,
Mz includes encoders Ex, Ey, and Ez for detecting the rotation amounts of the respective motors from the origin.
Servo drive unit Sv corresponding to Ey, Ez
A feedback signal is sent to x, Svy, and Svz. These encoders Ex, Ey, E
The signal z is transmitted to the control device 31 as position information indicating the three-dimensional position of the measuring head 20. The drive motor My further includes a brake device B. The brake device B is also controlled by the control device 31.

Each control step in the control flowchart shown in FIG. 3 represents a function realizing means. Step S1 is
A movement command is output to the X, Y axis motors Mx, My to output X, Y
Of the measuring head 20
Is located at a position P1 that is considerably away from the hole entrance on the axis of the measurement hole H, which is exemplified as a location to be measured, and then the Z-axis motor Mz is driven to rapidly move the measurement head 20 to measure near the entrance of the measurement hole H. The fast-forward commanding means for moving to the measurement preparation position P2 for moving to the measurement preparation position P2 facing the hole H in the Z-axis direction, and Step S2 includes encoders Ex to Ez of each motor.
From the measurement preparation position P2
The determination means for determining whether or not has been reached, step S3,
After the servo drive units Svx and Svy of the X and Y axes are turned off (power OFF), the relays MCx and Svx are turned off.
MCy is disconnected from the normally open relay contact MCx1-
3, MCy1-3, and a command means for outputting a command to operate the brake device B of the Y-axis motor My with brake.
When the control is shifted to step S3 through step S3, a command to turn on the Z-axis servo drive unit Svz after turning on the relay MCz is further output.

A step S4 controls the Z-axis motor Mz to measure and feed (slow-speed feed) the measuring head 20 in the Z-axis direction (measuring direction) and send it to the measuring position P3. Measurement completion determining means for determining whether all the measurements in the measurement hole H have been completed, step S6
Is a fast-forward retreat command means for controlling the Z-axis motor Mz to quickly retreat the measurement head 20 in the Z-axis direction and return the measurement head 20 to the measurement preparation position P2. Step S7 is to return to the measurement preparation position P2. Is confirmed by signals from the encoders Ex to Ez, step S8 is a means for determining whether there is another measurement hole H1 to be subsequently measured, and step S9 is a relay MCx when there is no other measurement hole H1. ,
When MCy is energized, its normally open relay contact MCx1-3, M
After closing Cy1-3 and turning on the drive motors Mx and My for the X and Y axes, the servo drive units Svx and Svx
command means for turning on the servo vy and outputting a command to release the brake device B of the Y-axis motor My, step S10
Drives the X, Y, Z axis motors Mx, My, Mz,
Origin returning means for quickly returning the measuring head 20 to a predetermined origin position P0. Step S11 is a step S8 in which, when there is another measuring hole H1 in step S8, in addition to the command of step S9, Z
Command means for turning off the relay MCz after turning off the axis servo drive unit Svz and opening the contacts MCz1-3 to cut off the power supply to the Z-axis motor Mz. Step S12 is a measurement reference for the other measurement holes H1. This is a fast-forward command means for moving the measuring head 20 by moving the X and Y axes to a position. The opening / closing command means in the present application includes the command means of steps S3, S9, and S11.

The brake device B is released, and the three relays MCx, MCy, MCz are turned on, all the relay contacts MCx1-3, MCy1-3, MCz1-3 are closed, and the servo drive units Svx, Svy, Sv are closed.
When a fast-forward command is issued from the control device 31 in step S1 in a state where z is servo-ON (power supply), first, the X and Y axis motors Mx and My are driven to set the respective screws in the X and Y axis directions. The measuring head 2 is fed via the feed mechanisms 10 and 13.
0 is rapidly moved to a position P1 which is considerably away from the measurement hole H on the axis of the measurement hole H. Further, the measuring head 20 is quickly moved along the column 9 in the Z-axis direction by the Z-axis motor Mz, and reaches the measurement preparation position P2 close to the entrance of the measuring hole H. In step S2, when it is confirmed from the signals from the encoders Ex to Ez of the respective drive motors Mx to Mz that the measuring head 20 has reached the measurement preparation position P2, the servo drive units Svx and Svy are turned off in step S3. After that, the relay contacts MCx1-3, MCy1
Open -3. Thereby, the X and Y axis drive motors Mx,
My is completely turned off electrically. Further, in step S3, subsequently, the brake device B of the Y-axis motor My is braked to mechanically lock the Y-axis motor My. Generally, a servo drive unit is provided with a failure detection circuit that considers disconnection and other abnormalities when power supply to a drive motor to be controlled is cut off in a state where the servo drive unit is electrically ON (servo ON). Therefore, in step S3, after the servo drive units Svx and Svy are turned off, the relay contacts M
The reason why Cx1-3 and MCy1-3 are opened is that such a failure detection circuit operates and does not generate an alarm.

Next, in step S4, a slow rotation command is issued to the Z-axis motor Mz, and the measuring head 20 moves forward on the axis of the measuring hole H toward the measuring hole H. Measurement hole H
In the process of entering the position, the feed in the Z-axis direction is stopped at the axial position to be measured, that is, at the measurement position P3, and the inside diameter of the measurement hole H is measured by the measurement head 20 at that position. The measurement data is sent to the control device 31, and it is determined whether or not the measurement data is within a predetermined processing error range. Same measurement hole H
In, when there is another measurement position having a different axial position, the measurement head 20 moves again in the Z-axis direction, reaches the next measurement position, and performs measurement.

If it is determined in step 5 that the measurement of the inner diameter of the measurement hole H for which the measurement is currently being performed has been completed, the measurement head 20 moves backward in the Z-axis direction at a rapid traverse in step S6. When it is confirmed in step S7 that the workpiece W has returned to the measurement preparation position P2 and has slipped out of the measurement hole H in the axial direction, in step S8, another measurement to be performed on the workpiece W currently being measured is performed. It is determined whether or not there is a hole H1.
After closing the relay contacts MCx and MCy in step 9, the servo drive units Svx and Svy are turned on and the braking state of the brake device B is released. Then, the rotation of the three drive motors Mx, My, and Mz is controlled, and the measurement head 20 is returned to the origin position P0 by rapid traverse.

On the other hand, if there is another measurement hole H1 in step S8, in addition to the same control as step S9 in step S11, the Z-axis servo drive unit Svz
After the servo is turned off, the relay contact MCz is opened. As a result, the drive motor Mz is turned off. Next, at step S12, the drive motors Mx, M
y is driven and controlled to coincide with the hole axis of the next measurement hole H1,
It moves to the measurement preparation position P2a approaching the entrance of the measurement hole H (here, the front surface WF (the surface facing the measurement head 20) of the work is described as a surface orthogonal to the Z axis: FIG. 1). Then, in step S2, the measurement preparation position P
2a, it is confirmed that step S11 has been reached.
In step S3, the servo drive units Svx and Svy are servo-off, the relay contacts MCx1-3 and MCy1-3 are opened, and the brake device B of the Y-axis motor My is braked. Then, after closing the relay contact MCz, the servo drive unit Svz is set to servo ON, and thereafter, the steps S4 and thereafter are executed as described above.

As is apparent from the above description, the measurement head 20 is positioned at the measurement preparation position P2 located outside the measurement hole H in the axial direction.
Before starting to enter the measuring hole H from the above, the power supply to the X and Y axis drive motors Mx and My is turned off, and the measuring head 2 is turned off.
Since the power supply to the X and Y axis drive motors Mx and My is turned ON after 0 returns to the measurement preparation position P2 again, during this time (while the measurement head 20 is located in the measurement hole H).
In the movement control program of the measuring head 20 previously input to the control device 31, there is a program error relating to the movement in the X and Y axis directions, or external electrical noise acts on the control device 31, X, Y
Even if you try to make the axis motion runaway,
The X and Y axis motors x and My never rotate, so that the collision of the measuring head 20 with the inner wall of the measuring hole H can be completely eliminated, and the expensive measuring head 20 may be damaged or not. It is possible to reliably prevent the subsequent measurement from being impossible due to severe damage. In the above embodiment, the drive motor M in the direction of the gravitational force (Y-axis direction) is used.
Since y is mechanically locked by the brake device B, the effect of gravity acting downward on the lifting head 12 can be completely avoided, and the measurement head 20 can be more reliably fixed in the Y-axis direction.

When there are a plurality of measurement holes H in the same work W, the measurement head 20 is moved to the measurement preparation position P.
2, the measurement preparation position P2a for the next measurement hole H1 is returned.
Before moving by the X and Y axis movements, the Z axis motor Mz is turned off, and when it reaches the measurement preparation position P2a of the next measurement hole H1, the X and Y axis motors Mx and My are turned off and the Z axis is turned off. Since the power of the motor Mz is turned on, during the rapid traverse movement from the measurement preparation position P2 to the next measurement preparation position P2a,
The measuring head 20 does not absolutely move in the Z-axis direction due to a program error, electric noise, or the like. In particular, as in the above embodiment, the measuring head 20 is kept very close to the entire surface of the work. In the case where the measuring head 20 moves in the X and Y axis directions, the measuring head 20 is prevented from unexpectedly moving in the Z axis direction during the movement, and interference with the workpiece W in the Z axis direction can be completely avoided. .

In the above-described embodiment, the rapid movement of the measurement head 20 to the measurement preparation position P2 may be achieved by simultaneously driving three drive motors Mx, My and Mz. The measurement preparation position P2 is an axial position very close to the measurement hole H on the axis of the measurement hole H. In particular, one work is provided with many measurement holes H, and the entrance of each measurement hole H When the positions are different in the Z-axis direction, the measurement preparation position P2 is the measurement hole H whose Z-axis direction position is closest to the measurement head 20 among the plurality of measurement holes H.
It may be located close to the entrance of the building. Further, in the embodiment of the present application, the example in which the movement in the Z-axis direction is performed by moving the entire column has been described. However, the present invention is not limited to this, and the quill system in which only the main shaft on which the measuring head is mounted moves in the Z-axis direction. Is also good.

[0020]

As described above, according to the present invention, while the measuring head moves from the measurement preparation position to the measurement position, no electric power is supplied to the drive motor that controls the movement in the direction orthogonal to the measurement direction. Even if a program error or an electric noise enters, it never operates and the measuring head can be prevented from moving in the orthogonal direction. Also, in the present application, while the measuring head is located in the hole to be measured, power is not supplied to the drive motor that controls the movement in the orthogonal axis direction orthogonal to the hole axis direction. Even if the target noise enters, it never operates and the measuring head is prevented from moving in the orthogonal direction, so that the measuring head can be prevented from hitting the inside of the hole and being damaged. Further, in the present application, when the axial direction of the measuring head is the horizontal axis direction, and two orthogonal axes of the left and right are the upper and lower axes, the drive motor for the upper and lower axes is a motor with a brake.
Since the brake is actuated together with the electromagnetic contactor OFF, even if the measuring boat head attempts to move downward due to gravity, this can be prevented, and the vertical movement in the vertical direction is more reliably prevented.

Further, in the present application, when moving from one of a plurality of measuring points to the next measuring point, the power supply to the drive motor for moving the measuring head in the axial direction is cut off, and the remaining two orthogonal axes are moved. The movement can be performed by the control, and it is possible to prevent the measurement head from moving in the axial direction and interfering with the workpiece during the movement from the measurement location to the next measurement location due to a program error or the like.

[Brief description of the drawings]

FIG. 1 is an overall side view of a measuring device.

FIG. 2 is a diagram showing control means of a measuring head.

FIG. 3 is a control flowchart.

FIG. 4 is a diagram showing movement of a measuring head.

[Explanation of symbols]

 Reference Signs List 20 measurement head 35 power line H measurement hole P0 origin position P2 measurement preparation position P3 measurement position Mx drive motor for X axis My drive motor for Y axis Mz drive motor for Z axis MCx relay (electromagnetic contactor: electric opening / closing means) ) MCy relay (electromagnetic contactor: electrical switching means) MCz relay (electromagnetic contactor: electrical switching means) Svx servo drive unit (for X-axis motor) Svy servo drive unit (for Y-axis motor) Svz servo drive unit (for Z-axis motor) For) W work

Claims (8)

[Claims] 1. A measuring head moves relative to a workpiece by movement in a measuring direction and movement in a direction perpendicular to the measuring direction, and moves from a measurement preparation position facing a measured portion of the workpiece in the measuring direction. A measuring device that reaches a measuring position for measuring a measurement target position, wherein the measuring head is positioned at the measuring position in a state where power supply to a drive motor that controls movement in a direction orthogonal to the measuring direction is cut off. Method for controlling the movement of the measuring head. 2. A method according to claim 1, wherein the measuring head is moved relative to the workpiece in an axial direction and in a direction perpendicular to the axial direction, so that a hole to be measured formed in the workpiece and the measuring head are moved in the axial direction of the hole. After the measurement head is moved in the hole axis direction, the measurement device enters the hole and reaches the measurement position. When the measurement head is positioned in the hole,
A movement control method for a measuring head, wherein power supply to a drive motor that controls movement in an orthogonal axis direction orthogonal to a hole axis direction is cut off. 3. A measuring part of a workpiece and a measuring head are:
The measurement head is positioned at a measurement preparation position facing the measurement target position by relatively moving at least in two orthogonal directions perpendicular to the axial direction of the measurement head, and the measurement head is moved from the measurement preparation position to the measurement measurement position. In a measuring device that relatively moves in the axial direction and reaches a measurement position, in the middle of a power line to two drive motors that move in the orthogonal two-axis direction,
The electric opening / closing means is interposed, and the electric opening / closing means is opened while the measuring head returns from the start of the axial movement from the measurement preparation position to the measurement position to the measurement preparation position again. Head movement control device. 4. A measuring head provided movably in three axial directions including a measuring head axial direction and orthogonal to each other, a driving motor for moving the measuring head in each axial direction, and controlling each driving motor. A measuring device comprising a motor drive unit and a measuring head for moving a measuring head in an axial direction to reach a measuring position after a measuring head is opposed to a measuring preparation position facing a measured portion of a workpiece. A drive motor that moves in two orthogonal directions except the above and a corresponding motor drive unit are connected via an electromagnetic contactor, and the electromagnetic contactor is provided with opening and closing command means for opening and closing based on position information of the measuring head. A movement control device for the measuring head. 5. The drive motor is a servomotor, and the opening / closing command means turns off the motor drive unit when it confirms that the measurement head has reached the measurement preparation position based on the position information of the measurement head. 5. The movement control device of the measuring head according to claim 4, wherein the control device is configured to turn off. 6. An axis direction of a measuring head is a horizontal axis direction, and two orthogonal axes of the left and right are vertical and vertical axes, and a drive motor for the vertical axis is a motor with a brake. The movement control device of the measuring head according to claim 4 or 5, wherein the device is configured to operate. 7. A measuring head provided movably in three axial directions including the measuring head axial direction and orthogonal to each other, a driving motor for moving the measuring head in each of the axial directions, and controlling each driving motor. A measuring device comprising a motor drive unit and a measuring head for moving the measuring head in an axial direction to reach a measuring position after the measuring head is opposed to a measuring preparation position facing a measured portion of the workpiece; Measuring head comprising opening / closing command means for connecting a driving motor for movement and a corresponding motor drive unit via an electromagnetic contactor, and for opening / closing the electromagnetic contactor based on positional information of the measuring head. Movement control device. 8. The movement control device for a measurement head according to claim 3, wherein the measurement head is for measuring the inner diameter of the hole, and enters the hole of the workpiece by axial movement.