JP2003114115A - Escape mechanism of probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an escape mechanism of a probe capable of preventing failure and degradation of a probe and an object to be measured and realizing repeatability of high position recovery with a simple and cheap structure. SOLUTION: Inside a box 2 installed at the arm part of a characteristic measuring device, an actuator 13, a moving part 8 capable of seating on the box 2 and a positioning mechanism for positioning the moving body 8 at a specific position of the box 2 are provided. When abnormality is detected with a detection signal from the probe 21, the actuator 13 moves upward the moving part 8 and let the probe 21 escape. The recovery of the probe 21 position is done after waiting for a recovery command of the measuring device. If the drive force to the actuator 13 reduces, then the moving part 8 sits on the specific position of the box 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe escape mechanism used in a three-dimensional measuring device or the like.

[0002]

BACKGROUND ART In a three-dimensional measuring device, a probe movable in three dimensions is brought into contact with an object to be measured placed on a fixed base, and the moment when the probe comes into contact with the object to be measured is used as an electrical trigger. The feed coordinate values of each axis in the three-dimensional direction are read, and the dimensions and shape of the object to be measured are measured based on these coordinate values. Conventionally, as one of the contact-type probes used for this measurement, there is an ultrasonic probe disclosed in JP-A-6-221806 or Japanese Patent No. 3130289. These are equal to the axial natural frequency of the stylus holder, the stylus supported by the stylus holder and having a contactor for contacting the object to be measured at the tip, and the center of gravity of the stylus as a vibration node. A configuration including a vibrating unit that vibrates the stylus at the frequency of vibration and a detecting unit that detects the contact from the change in the vibration state that occurs at the time of contact with the object to be measured, is called a touch signal probe.

Generally, a touch signal probe has a detection mechanism for detecting a slight movement of the stylus when it comes into contact with an object to be measured, and an escape mechanism for preventing the probe from being damaged by a large movement of the probe. Equipped with. The escape mechanism has a retracting function that allows the stylus to move largely with respect to the probe housing, and a restoring function that returns the stylus to its original position before the operation after the operation. Has a function of always positioning the stylus at a fixed position (this position is referred to as a sitting position or a rest position), and high repeatability is required.

As disclosed in Japanese Patent Laid-Open No. 5-248847, the escape mechanism holds the probe in a predetermined posture in the housing by utilizing the biasing force of a spring, and when a contact force of a certain amount or more is applied to the probe, A so-called passive escape mechanism that retracts the probe by pushing it into the housing by force, and a so-called active mechanism that activates the actuator to retract the probe when it detects that the probe has contacted the DUT. The escape mechanism is known.

As the latter active escape mechanism, there are JP-A-7-318305 and JP-A-2001-141442. Japanese Patent Application Laid-Open No. 7-318305 is a touch signal probe in which an exciting coil and a fixed yoke are provided in a housing of a probe, and an armature is provided on an upper part of the stylus of the probe. When the stylus comes into contact with an object to be measured, A current flows through the exciting coil, and the magnetic attraction force pulls up the armature, thereby retracting the probe.

Further, the one disclosed in Japanese Unexamined Patent Application Publication No. 2001-141442 is a touch signal probe provided with an actuator such as a piezoelectric element provided above the stylus and a displacement sensor for monitoring the displacement of the stylus. When contact with an object is detected, the actuator contracts and retracts the probe. In order to prevent reproducibility deterioration due to actuator drift when restoring the position,
The position of the probe is monitored by a displacement sensor, and the position is restored by feedback control.

[0007]

However, the escape mechanism of the touch signal probe as described above has the following problems. 1) The passive escape mechanism applies a constant pressing force to the probe and the object to be measured while the probe is retracted, and may deform if the object to be measured is soft, and is used for a small probe. In this case, the probe may be damaged or the contact at the tip may deteriorate.

2) On the other hand, in the active escape mechanism, in the case of Japanese Patent Laid-Open No. 7-318305, a structure such as an exciting coil for performing an escape operation must be provided on the upper portion of the probe, which makes the structure complicated and expensive. In addition, JP-A-200
In the case of 1-141442, it is necessary to attach a displacement sensor in order to improve reproducibility when restoring the position after the escape operation, and the structure is also complicated and expensive.

It is an object of the present invention to provide a probe escape mechanism which prevents damage and deterioration of the probe and the object to be measured, has a simple and inexpensive structure, and can realize high position restoration reproducibility.

[0010]

Therefore, according to the present invention, an actuator and a movable part are provided in a housing of a probe, an active escape mechanism for moving the movable part by the actuator and retracting the probe is provided with a seat part and a seating part. It is intended to achieve the above-mentioned object by providing a positioning mechanism for positioning the movable part when the movable part is seated by abutting. Specifically, the escape mechanism of the probe according to claim 1 includes a casing mounted on an arm of a measuring device that measures the property of the object to be measured, and an actuator having one end fixed to the casing. A movable part that is attached to the other end of the actuator and can be seated on the housing, and a seat part and the movable part formed on the housing so that the movable part can contact the seat part. A positioning mechanism that includes a seated portion and that positions the movable part at a fixed position with respect to the housing when the movable part is seated; and a state that is attached to the movable part and changes according to the relationship with the DUT. Detecting the amount, the probe holder that couples the probe that outputs the detection signal, and monitor the detection signal,
When an abnormality of the detection signal is detected, there is provided escape operation control means for performing an avoiding operation of the actuator in a direction in which the seat portion of the movable portion is separated from the seat portion of the housing.

In the present invention having this structure, when the escape control operation control means detects an abnormality in the detection signal from the probe, the actuator is operated to retract the probe, thereby damaging both the probe and the object to be measured. Can be avoided. Further, according to the present invention, when the probe position is restored after the escape operation, since the seating portion abuts on the seat portion and the movable portion seats at the fixed position, a displacement sensor as in the prior art is not required. Therefore, high position restoration reproducibility can be realized with a simple and inexpensive structure.

The escape mechanism of the probe according to claim 2 is
2. The positioning mechanism according to claim 1, wherein the seating portion of the housing is provided with three hard balls arranged facing the seating portion and arranged at substantially equal angular intervals around the probe. To do. In the present invention having this configuration, since the three hard balls are arranged at substantially equal angular intervals, the seated portion of the movable portion can be stably seated on the seat portion of the housing, and the position of the movable portion can be restored. High reproducibility can be realized.

The escape mechanism of the probe according to claim 3 is
The probe according to claim 1 or 2, wherein the probe detects a contact with the object to be measured and outputs a detection signal according to the magnitude of the contact force.
In the present invention having this configuration, since the detection signal level changes in accordance with the contact force of the probe, it is possible to know how much the probe is pushed into the object to be measured, and use that information for escape operation control of the probe. Because you can
More precise escape operation control is possible.

The escape mechanism of the probe according to claim 4 is
The escape operation control means according to any one of claims 1 to 3, when the detection signal level changes in the abnormal direction detection direction, the detection signal level changes to a preset first threshold value. When outputting the operation stop request signal to the measuring device and detecting that the detection signal level has exceeded the first threshold value and has reached a preset second threshold value, the actuator avoidance operation is performed. It is characterized by In the present invention having this configuration, when the level of the detection signal from the probe reaches the first threshold value, the operation stop request signal is output to the measuring device, and the operation of the measuring device is stopped based on the signal. In addition, a second threshold for avoidance commands is provided separately from the first threshold for operation stop, so if the operation stop command is not issued due to some malfunction, or if it cannot be stopped immediately due to inertia etc. Also, since the probe is retracted by the avoidance command, the probe can be controlled more safely, and damage to both the probe and the object to be measured can be avoided more reliably.

The escape mechanism for the probe according to claim 5 is:
The escape operation control means according to any one of claims 1 to 4, in response to a restoration command from the measuring device in a state where a seated portion of the movable portion is separated from a seat portion of the housing. The actuator is seated in a direction in which the movable portion is seated. In the present invention having this configuration, since the position is restored after waiting for a restoration command, which is a signal for preparation for the next measurement posture from the measuring device, the probe and the object to be measured can be protected more safely and reliably from damage. For example, if the probe retracts in response to the avoidance command and the measuring device performs the touchback operation, the controller of the measuring device outputs the restoration command after receiving the completion signal of the touchback operation of the measuring device. , The avoidance command is released as soon as the probe avoids the object to be measured, and the probe does not perform the position restoration operation without waiting for the completion of the touchback operation. Damage to both sides can be avoided.

The escape mechanism for the probe according to claim 6 is:
7. The preload mechanism according to claim 1, further comprising a preload mechanism capable of adjusting a distance between the seat portion and the seat portion in a seated state and a pressing force of the seat portion with respect to the seat portion. It is characterized by In the present invention having this configuration, the distance between the seated portion and the seat portion can be adjusted so that the seated portion surely contacts the seat portion, and further, in order to surely seat when the probe position is restored. Since the pressing force can be set, the reproducibility and the repeat accuracy when restoring the probe position are improved.

The escape mechanism of the probe according to claim 7 is
In any one of Claims 1 to 6, the actuator is a piezoelectric element or a magnetostrictive element. In the present invention having this configuration, when an abnormality is detected in the detection signal from the probe, voltage is applied to or removed from the actuator, the actuator expands and contracts, and the probe retracts together with the movable part. When the position of the movable part is restored, the actuator is expanded or contracted by removing or applying a voltage to the actuator to return the movable part to the position before the movement. The probe can be retracted by simply applying or removing a voltage.
Since the position can be restored, the structure can be simplified,
It will be relatively cheap.

The escape mechanism for the probe according to claim 8 is:
In claim 2, the seating portion is any one of a flat surface, a tapered shape, and a curved surface. In the present invention having this configuration, due to these shapes, the movable portion can be reliably seated on the seat portion provided in the housing, and high position restoration performance and high repeatability can be realized. In particular, with a taper or a curved surface, the movable portion can be positioned even in the direction orthogonal to the probe axis.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. Usually, the probe has a low rigidity with respect to a displacement displaced in a direction orthogonal to the axial direction of the stylus, that is, in a lateral direction, and is less likely to be broken even if the probe comes into contact with the object to be measured and is further depressed. However, since the stylus has a high rigidity against axial displacement, it is easily buckled when pushed in this direction. In this embodiment, an example will be described in which the probe performs an escape operation in one axial direction in which the probe is most likely to be damaged.

FIG. 1 is a sectional view of this embodiment. The probe escape mechanism 1 of the present embodiment includes a housing 2 connected to an arm of a measuring device, specifically, a Z-axis spindle (a member that moves in three-dimensional directions) 41 of a three-dimensional measuring device,
An actuator 13 whose one end is fixed to this housing 2
And a movable part 8 which is attached to the other end of the actuator 13 and can be seated on the housing 2, and the movable part 8 is positioned at a fixed position with respect to the housing 2 when the movable part 8 is seated. The positioning mechanism 11 and the probe holder 14 which is mounted on the movable portion 8 and which is connected to the probe 21 that detects the state quantity that changes according to the relationship with the object 51 to be measured and that outputs the detection signal, The detection signal is monitored, and escape operation control means 17 (see FIG. 3) for causing the actuator 13 to perform an avoidance operation when an abnormality of the detection signal is detected.

The casing 2 is provided with a cylindrical case 4 and a lid member 3 which is mounted in an opening on the upper surface of the case 4 and has a shank 3A connected to the Z-axis spindle 41 on the upper surface. The case 4 has three different inner diameters that become smaller as it goes downward, and is formed by a first step portion 6 formed by the difference between the inner diameters of the uppermost portion and the central cylindrical portion and a difference between the inner diameters of the central portion and the lowermost cylindrical portion. And a second step portion 7. As shown in FIG. 2, on the upper surface of the first step portion 6, three grooves 5A that are concave at a constant distance from the central axis of the cylinder of the case 4 and are conically recessed at positions having an angle of 120 degrees to each other, A seat 5 having three hard balls 5B arranged on the groove 5A is formed.

The actuator 13 is a circular tube type laminated PZT.
It is composed of a piezoelectric element such as, and can be expanded and contracted in the length direction (vertical direction) by applying and removing voltage, and the lower end (one end)
Is fixed to the upper surface of the second step portion 7, and the upper end (the other end) is the movable portion 8
It is fixed to the underside of.

The movable portion 8 is a disk-shaped flat surface, and is seated on the hard sphere 5B at a seating portion 9 formed at a position facing the hard sphere 5B of the case 4 so as to be movable in the axial direction. A preload mechanism 10 is provided at 9. The preload mechanism 10 has screw holes 10A cut in three seating portions 9 of the movable portion 8, and screws 10B are screwed into the screw holes 10A from the lower surface. The screw 10B is
The head is formed in a flat shape, and the flat portion abuts on the hard ball 5B. When the escape mechanism 1 is assembled, the actuator 13
With the screw 10B contracted, the movable portion 8 is the head of the screw 10B by changing the height position of the screw 10B so that the three heads come into contact with the three hard balls 5B. The seating portion 9 can be adjusted so as to surely contact the hard ball 5B. Further, by further increasing the height of the screw 10B, the pressing force against the hard ball 5B at the seating portion 9 is generated, so that these pressing forces can be made constant by the three screws 10B. If the screw 10B of the preload mechanism 10 is fixed with a double nut, the play of the screw is eliminated, and the height and the pressing force can be adjusted more accurately.

The positioning mechanism 11 includes a seat portion 5 having a groove 5A and a hard ball 5B of the case 4, and a seat portion 9 of the movable portion 8.
After the escape operation is performed, the sitting portion 9 sits on the hard ball 5B to position the movable portion 8 (probe 21) at a fixed position in the vertical direction. here,
In order to improve the positioning accuracy of the tip of the probe 21, it is important that the movable portion 8 is in contact with the hard ball 5B at the seating portion 9 when the position of the probe 21 is restored. However, in reality, it is difficult to make the heights of the three hard balls 5B exactly the same. Therefore, by the preload mechanism 10, the seating portion 9 of the movable portion 8 contacts the hard ball 5B,
In addition, the pressing force is adjusted so as to be kept constant.

The probe holder 14 is connected to the center of the lower surface of the movable portion 8, penetrates the actuator 13 and the housing 2, and holds the probe 21 at the lower part. Probe holder 1
4 is for easy replacement of the probe 21,
The probe insertion hole 15 at the bottom and the insertion hole 1 for this probe
5 and a set screw 16 for fixing the probe 21 inserted in the same.

The probe 21 has a stylus 22 at the bottom.
Further, the stylus 22 is provided with a contactor 23 that comes into contact with the object to be measured 51 at the tip of the stylus 22 and always outputs a detection signal indicating the contact state of the contactor 23. This detection signal is the contact 2
3 changes when it contacts the object 51 to be measured, and when it is further pushed into the object 51 to be measured, it changes according to the contact force.

As shown in FIG. 3, the escape operation control means 17 is composed of a signal processing circuit 18 and an actuator driving amplifier 19, and the detection signal level processed by the signal processing circuit 18 is a preset first level. When the threshold is reached, the signal processing circuit 18 causes the controller 31 of the measuring device to
To stop the operation and output a coordinate reading request signal. Further, when the detection signal level exceeds the first threshold value and reaches the second threshold value set separately, the signal processing circuit 18 determines that there is an abnormality, and the actuator driving amplifier 1
The avoidance command is output to 9. The position restoration of the probe 21 saved by this avoidance command is performed by the controller 3 of the measuring device.
It is performed after waiting for the restoration command from 1.

Next, the control method of this embodiment will be described. A certain detection signal is always output from the probe 21 to the signal processing circuit 18 (see FIG. 3). The signal is rectified into a DC signal as shown in FIG. 4, and the contact state is detected by monitoring the voltage level of this DC signal.

In FIG. 3, the probe 21 is an object to be measured 5.
1 is in a non-contact state. In this state, the seating portion 9 of the movable portion 8 is seated on the hard ball 5B. When the contact 23 of the probe 21 comes into contact with the DUT 51, the voltage level of the DC signal decreases as shown in FIG. At this time, the first threshold value and the voltage level of the detection signal are compared. When the voltage level of the detection signal reaches the first threshold value, it is recognized that the probe 21 has come into contact with the DUT 51, and a request signal for operation stop and measurement coordinate reading is output to the controller 31 of the measuring device. In the normal operation, the operation of the measuring device is stopped and the coordinate reading operation is performed by the request signal, and the Z-axis spindle 41 is separated from the measured object 51 so that the probe 21 is not pushed into the measured object 51 any more. Touch back operation is performed to move to.

However, if the operation is stopped or the touchback operation is not performed due to some trouble, the probe 21
Is further pushed into the object to be measured 51, and as a result, the voltage level of the DC signal further decreases. When this voltage level reaches a second threshold value lower than the first threshold value, the sent detection signal is recognized as an abnormal signal by the signal processing circuit 18, and an avoidance command is issued from the signal processing circuit 18 as an actuator driving amplifier 19 Sent to. The actuator 13 obtains a driving force and extends upward so that the seating portion 9 of the movable portion 8 moves to the hard ball 5
Separate from B. As a result, the probe 21 moves the movable part 8
At the same time, it escapes upward.

When the avoidance command is output from the signal processing circuit 18, the actuator 13 drives to perform the escape operation, and the controller 31 of the measuring device outputs the avoidance operation command to the drive system of the Z-axis spindle 41. The Z-axis spindle 41 stops the measurement operation, and the DUT 51 and the probe 2
The touchback operation is performed in the direction away from the DUT 51 so that 1 does not interfere. When this touchback operation is completed, a completion signal from the drive system of the Z-axis spindle 41 is sent to the controller 31 of the measuring device. In response to this completion signal, the controller 31 of the measuring device outputs a position restoration command for the probe 21 to the actuator driving amplifier 19.

At this time, it is very important to restore after receiving the touchback operation completion signal from the controller 31 of the measuring device. If this command is issued only by the signal processing circuit 18, the actuator 13 escapes. The contact state of the probe 21 is released by the operation, and a restore command is issued to the actuator driving amplifier 19 before the touchback operation of the Z-axis spindle 41 is completed, and the probe 21 and the object to be measured 51 may be contacted and damaged. Because.

When the restoration command is output, the driving force applied to the actuator 13 is reduced, the actuator 13 contracts downward, and the movable portion 8 is seated on the hard ball 5B. At this time, since the movable portion 8 is provided with the preload mechanism 10 and the movable portion 8 is adjusted in advance so as to have a constant pressing force against the hard ball 5B, the reproducibility of the position restoration is further improved. I'm sure.

Therefore, according to the present embodiment, the probe 21 is retracted by detecting the contact of the probe 21 with the object 51 to be measured and operating the actuator 13 to move the movable portion 8 upward. Therefore, damage to both the probe 21 and the measured object 51 can be avoided. Further, when the position is restored, the seating portion 9 of the movable portion 8
Sits on the hard sphere 5B and the position is restored reliably, so
A displacement sensor for checking and adjusting the restored position of the probe 21 is not required. Therefore, the structure can be simplified and the cost is reduced.

Further, since the threshold value is provided for the contact detection signal in two steps, the probe 21 can be retracted even if some trouble occurs, and the probe 21 can be controlled more safely. Even when the position of the probe 21 is restored, the restoration command is output after the touchback operation of the Z-axis spindle 41 is completed, so that the probe 21 and the DUT 51 can be more reliably prevented from being damaged. .
Furthermore, since the preload mechanism 10 can adjust the movable portion 8 to be seated on the hard ball 5B with a constant pressing force, the reproducibility of the position restoration of the probe 21 is good. In addition, since the actuator 13 is a piezoelectric element, voltage application /
Since the movable part 8 can be moved up and down by removal, the structure can be simplified and the cost is relatively low.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention. For example,
Although the preload mechanism 10 is installed on the movable portion 8 side in the present embodiment, the present invention is not limited to this, and it may be provided near the hard ball 5B on the housing 2 side or on both sides. Furthermore, if the contact between the hard ball 5B and the movable portion 8 at three locations is ensured, it is possible to install the preload mechanism 10 at one location outside the lower part of the housing 2 as shown in FIG. . That is, since the preload mechanism 10 is screwed into the screw hole provided in the case 4 and the upper surface is fixed to the lower surface of the actuator 13, the pressing force can be increased by moving the upper surface of the preload mechanism 10 up and down. Can be adjusted. In this case, since the pressing force can be adjusted from the outside of the housing 2, the adjustment can be easily performed.

Further, in the present embodiment, the shape of the movable portion 8 is flat, but as shown in FIG. 6, the portion in contact with the hard sphere 5B has a downward tapered shape (A), or conversely. It may have a tapered (B) shape or an inwardly curved shape (C) as long as it can stably seat on the three hard balls 5B.

Further, in the present embodiment, the actuator 1
Although the probe 21 escaped by expanding the piezoelectric element of No. 3, the actuator 13 is arranged above the movable portion 8 as shown in FIG. 7, and the actuator 13 is expanded when the probe 21 is not in contact. The same effect as that of the present embodiment can be obtained even with a mechanism in which the seat 21 is seated, and when the probe 21 is in contact, the driving force is reduced by the avoidance command to contract the actuator 13 and the probe 21 escapes. . The material of the actuator 13 is also a piezoelectric element in the present embodiment, but any element or mechanism such as a magnetostrictive element or an electrostrictive element that generates displacement may be used.

Further, in the present embodiment, two thresholds for determining the contact state of the probe 21 are provided, but the present invention is not limited to this, and the avoidance command may be output at the first threshold, for example. In this case, the piezoelectric element operates every time the measurement operation is performed, regardless of whether the operation of the measurement device is normally stopped. Further, in the present embodiment, the hard sphere 5B is provided on the seat portion 5, but the shape is not limited to the hard sphere 5B and may be any shape such as a conical shape or a triangular pyramid shape that always supports the seating portion 9 at a fixed position. The mounting position of the seating portion 9 is provided on the movable portion 8 in the present embodiment, but it may be provided on the housing 2 side and the seat portion 5 (hard ball 5B in the present embodiment) may be provided on the movable portion 8. , A similar effect can be obtained.

Further, although the escape mechanism of the touch signal probe has been described in the present embodiment, the escape mechanism of the present invention is not limited to the contact type and can be applied to a non-contact type probe. In this case, the gap between the probe 21 and the measured object 51 is detected as the state quantity and compared with the first or second threshold value. Further, in the present embodiment, the escape mechanism in the axial direction of the probe has been described, but the present invention is not limited to the axial direction and can be applied to, for example, a direction orthogonal to the axial direction.

[0041]

As described above, according to the present invention, there is an effect that damage and deterioration of the probe and the object to be measured are prevented, the structure is simple, and high position restoration reproducibility is realized while being inexpensive.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the whole of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a control block diagram according to the embodiment.

FIG. 4 is a graph showing the displacement of the probe with respect to the object to be measured, the voltage level change of the detection signal, and the operation command in the same embodiment.

FIG. 5 shows another embodiment of the present invention, and is a cross-sectional view showing an entire case in which a preload mechanism is attached to a lower portion of a housing.

FIG. 6 shows another embodiment of the present invention and is a cross-sectional view showing a shape of a movable portion.

FIG. 7 shows another embodiment of the present invention, and is a cross-sectional view showing an entire case where an actuator is attached to the upper surface of a movable portion.

[Explanation of symbols]

1 escape mechanism 2 housing 5 seats 8 movable parts 9 Seating site 10 Preload mechanism 11 Positioning mechanism 13 Actuator 14 Probe holder 17 Escape operation control means 21 probe 51 DUT

Claims (8)

[Claims] 1. A casing mounted on an arm of a measuring device for measuring properties of an object to be measured, an actuator whose one end is fixed to the casing, and a casing mounted on the other end of the actuator, A movable part that can be seated on the housing, a seat part that is formed on the housing, and a seating portion that is formed on the movable part so as to be able to contact the seat part; A positioning mechanism for positioning the movable part at a fixed position with respect to the housing, and a probe attached to the movable part for detecting a state quantity that changes according to the relationship with the object to be measured and outputting a detection signal thereof. And a probe holder that couples the detection signal with each other, and when an abnormality of the detection signal is detected, an escape operation for avoiding the actuator in a direction in which the seated portion of the movable portion is separated from the seat portion of the housing. Motion control Probe clearance mechanism is characterized in that a stage. 2. The escape mechanism for a probe according to claim 1, wherein the positioning mechanism is arranged at a seat portion of the housing so as to face the seating portion and at substantially equal angular intervals about the probe. A relief mechanism for the probe, which is equipped with three hard balls. 3. The escape mechanism for a probe according to claim 1, wherein the probe detects contact with the object to be measured and outputs a detection signal according to the magnitude of the contact force. An escape mechanism for the probe characterized by: 4. The escape mechanism for a probe according to any one of claims 1 to 3, wherein the escape operation control means changes the detection signal level when the detection signal level changes in an abnormal detection direction. When it is detected that the preset first threshold has changed,
While outputting an operation stop request signal to the measuring device, when detecting that the detection signal level has exceeded the first threshold value and has reached a preset second threshold value, the actuator is caused to perform an avoiding operation. Characteristic probe escape mechanism. 5. The escape mechanism for a probe according to any one of claims 1 to 4, wherein the escape operation control means has a state in which a seat portion of the movable portion is separated from a seat portion of the housing. 2. A probe escape mechanism, wherein the actuator is seated in a direction in which the movable portion is seated in response to a restoration command from the measuring device. 6. The escape mechanism for a probe according to claim 1, wherein a distance between the seat portion and the seat portion in a seated state and a pressing force of the seat portion with respect to the seat portion are A probe escape mechanism comprising at least one adjustable preload mechanism. 7. The escape mechanism for a probe according to claim 1, wherein the actuator is a piezoelectric element or a magnetostrictive element. 8. The escape mechanism for a probe according to claim 2, wherein the seating portion is any one of a flat surface, a tapered shape, and a curved surface.