JPH0552542A - Moving mechanism of measuring piece of displacement detecting apparatus - Google Patents

Abstract

PURPOSE:To obtain a moving mechanism of a measuring piece of a displacement detecting apparatus, which is excellent in operability and, besides, in dustproofness and of which the structure can be simplified. CONSTITUTION:A driving mechanism 30 which drives a release rod 34 forward and backward in the direction of movement of a measuring piece 101, and a communication hole 22 formed along the fore end part of the release rod 34 of the main body 101, are provided. Moreover, an engaging mechanism 38 which is so disposed as to pierce the communication hole 22 and makes the release rod 34 and the measuring piece 101 engage with each other when the release rod 34 is moved in the direction of retrogression of the measuring piece 101, and a case 21 which closes up the release rod 34 to the engaging mechanism 38 by covering them up integrally, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracing stylus moving mechanism for moving a tracing stylus of a displacement detecting device during measurement or the like.

[0002]

2. Description of the Related Art Conventionally, as a device for measuring the size, shape, etc. of an object to be measured, a measuring element such as a spindle is provided, and the tip of the measuring element is brought into contact with the object to be measured from one direction. An apparatus of the type in which the displacement and the displacement are measured to measure the size and shape is often used. In some of such displacement detecting devices, a tracing stylus moving mechanism is mounted in order to displace the tracing stylus arbitrarily.

As the above-mentioned measuring element moving mechanism, first,
There is one in which the fingertip portion provided on the tracing stylus allows the tracing stylus to be displaced manually. However, in such a finger-hook type probe moving mechanism, although the structure is simple, it is easy to inadvertently apply a force other than the moving direction of the probe during operation, which causes a measurement error. In addition, the finger hooks protruding from the stylus may hinder the measurement work.

On the other hand, a tracing stylus moving mechanism using a release mechanism for indirectly operating the tracing stylus via a wire is adopted. In such an indirect release type tracing stylus moving mechanism, the driving force for the tracing stylus is constantly measured regardless of the direction of the operating side by holding the tracing stylus connection side of the wire in a fixed direction along the tracing stylus. The direction can be along the child, and the error due to the force in the other direction can be reduced.

On the other hand, in such an indirect release type probe head moving mechanism, in addition to a manual type in which the probe is manually operated, a remote controllable drive mechanism such as an air cylinder is used to automate the movement of the probe. Has been planned. In particular, when performing in-line measurement in the manufacturing process, it is possible to automate even the measurement operation in response to automation of the line, and in such a case, a remotely controllable stylus moving mechanism is extremely useful. is there.

A structure as shown in FIG. 7 has been proposed by the applicant of the present invention as a probe moving mechanism that can be remotely controlled by air or the like (Japanese Patent Application No. 2-95970). In FIG. 7, the displacement detection device 100 has a cylindrical main body 101.
The tip end side of 101 has a built-in stylus 110 that can move back and forth, and the main body 101 has a built-in detection mechanism 120 that detects the amount of movement of the stylus 110 on the base end side of the main body 101. Is equipped with a stylus moving mechanism 130.

The tracing stylus 110 has a rod-shaped spindle 111, and its tip has a contact tip 112 that abuts against an object to be measured.
Is provided. Spindle 111 is a bearing 115 consisting of balls 114 held in place by a retainer 113.
It is held in the main body 101 via the through so that it can move back and forth. A guide pin 116 is planted on the base end side of the spindle 111, and a guide hole 117 is formed in a portion of the main body 101 facing the guide pin 116 over a predetermined length. Guide pin 11
The tip end of 6 is inserted into and engaged with the guide hole 117, whereby the spindle 111 is movable for a predetermined stroke but its rotation is restricted.

A compression coil spring 118 is interposed between the base end of the spindle 111 and the main body 101.
As a result, the spindle 111 is urged toward the tip side of the main body 101, and when the object to be measured (not shown) in contact with the contact tip 112 moves, the spindle 111 follows. A stretchable tubular rubber boot 119 is mounted between the contact tip 112 and the tip of the main body 101. The rubber boot 119 always shields the part of the spindle 111 that extends from the main body 101 from the outside to ensure dustproofness. Has been done.

The detection mechanism 120 comprises a scale 121 connected to the base end side of the spindle 111, and a detector 122 fixed to the main body 101 at a position along the movement path of the scale 121. The scale 121 is a scale for optical reading, and has a stripe pattern formed on a transparent substrate at fine constant intervals.

The detector 122 is composed of a light emitting section 123 and a light receiving section 124 fixed to the main body 101 so as to sandwich the scale 121, and the light receiving section from the light emitting section 123 through the scale 121.
Every time the light beam reaching 124 is blocked by the striped pattern of the scale 121, the displacement is integrated and the movement of the scale 121, that is, the movement of the spindle 111 is detected. Detector 122
A cable 125 extending from the base end side of the main body 101 to the outside is connected to this, and by this cable 125, power supply and signal transmission from an external measuring device (not shown) to the light receiving part 123 and the light emitting part 124 are performed. There is.

The tracing stylus moving mechanism 130 includes a case 131 fixed to the main body 101, a slide plate 132 movably provided in the case 131, and a drive mechanism 133 for moving the slide plate 132 with respect to the case 131. Is equipped with. Case 13
1 is installed so as to cover the guide hole 117 of the main body 101, and has a communication hole 134 corresponding to the guide hole 117.

A contact pin 135 is planted on the tip side of the side surface of the main body 101 of the slide plate 132, and the contact pin 135 is a communication hole.
It is projected through 134 into the guide hole 117 and normally abuts on the guide pin 116 of the spindle 111 which is biased toward the tip side. A compression coil spring 136 is interposed between the slide plate 132 and the case 131.
When the slide plate 132 is biased toward the tip side of the main body 101 by the 136, and the spindle 111 and the guide pin 116 move to the base end side due to the movement of the object to be measured and the mutual contact is released. However, it is held in a fixed position.

The drive mechanism 133 has a case 137 connected to the bent portion on the base end side of the slide plate 132, and the case 137 is provided with a push rod 138 projecting toward the tip side. The tip of push rod 138 is case 131
And is driven by the internal air cylinder mechanism 140 to move forward and backward from the case 137 to move the slide plate 132 with respect to the case 131.

The air cylinder mechanism 140 includes a piston 141 slidably housed in a cylindrical portion inside a case 137.
The base end of the push rod 138 is connected to the piston 141. The piston 141 is a compression coil spring 14
At 2, the case 137 is constantly urged toward the base end side. Also,
A pressure pipe 143 reaching an unillustrated compressed air supply source is connected to the pressure chamber 143 on the base end side of the piston 141.

Here, the pressure chamber 14 is passed through the pressure pipe 144.
By introducing the compressed air into 3, the piston 141 moves toward the tip side of the case 137 against the coil spring 142, and the push rod 138 moves out of the case 137. As a result, the slide plate 132 is driven toward the base end side with respect to the case 131 together with the case 137, the contact pin 135 contacts the guide pin 116 and moves it toward the base end side, and the spindle 111 moves to the compression coil spring 118. It is moved to the proximal side against
Is retracted to the base end side of the main body 101.

Further, the pressure chamber 143 is passed through the pressure pipe 144.
By discharging the compressed air, the piston 141 moves to the base end side of the case 137 by the coil spring 142, and the push rod 138 retracts into the case 137. As a result, the slide plate 132 is driven together with the case 137 toward the front end side with respect to the case 131, and the guide pin 116 and the spindle 111, which come into contact with the contact pin 135 as the contact pin 135 moves toward the front end side, are moved forward by the compression coil spring 118. Moved to the contact point 11
0 is advanced to the tip side of the main body 101.

In the displacement detecting device 100 having such a tracing stylus moving mechanism 130, advance / retreat of the tracing stylus 110 can be freely controlled remotely by switching the air supply. Therefore, when applied to in-line measurement or the like, a great deal of automation and omission can be realized. In addition, since the direction of air driving when moving the tracing stylus 110 is along the moving axis of the tracing stylus 110, it is possible to prevent an error or the like due to a force in another direction. Since the tracing stylus moving mechanism 130 is provided along the main body 101 of the displacement detecting device 100, it is possible to eliminate obstacles such as interference with the surroundings due to upsizing of the device or restrictions on installation. Therefore, application to in-line measurement and the like can be performed very easily and in a wide range.
Furthermore, by exchanging the drive mechanism 133 attached to the slide plate 132 with a manual wire release type drive mechanism, it is possible to change it to a tracing stylus moving mechanism by manual operation.

[0018]

By the way, in the displacement detecting apparatus 100 having the tracing stylus moving mechanism 130 described above, since the replacement of the driving mechanism 133 is considered, the case 131 of the tracing stylus moving mechanism 130 and the driving mechanism 133 are considered. Since the case 137 is separated from the case 137 and the slide plate 132 needs to be partially exposed, the case 131 needs an opening.

However, when the case 131 has such an opening, surrounding oil, dust, and the like enter the case 131 through the opening when the case is used for in-line measurement during the manufacturing process, and further, the communication hole 134. Also, there is a possibility of entering the main body 101 through the guide hole 117. And the main body 101
If oil, dust, etc. enter inside, there is a problem that it will affect the detector 122, which requires precise optical characteristics, and it will not be possible to make accurate measurements. There is also a problem that the movement is hindered and accurate measurement cannot be performed.

Further, the tracing stylus moving mechanism 13 shown in FIG.
0 has a problem that the number of parts is large, the mechanism is complicated, assembly and maintenance are complicated, and it is difficult to reduce the manufacturing cost. Therefore, simplification of the structure is desired.

An object of the present invention is to provide a tracing stylus moving mechanism of a displacement detecting device which has good operability, good dust resistance and a simple structure.

[0022]

SUMMARY OF THE INVENTION The present invention is directed to a measuring element which is related to an object to be measured, a detecting device body which slidably supports the measuring element, and a measuring element which is installed in the detecting device body. A releaser which is attached to a displacement detection device equipped with a detector for detecting the amount of movement, and which is a probe moving mechanism for moving the probe in a desired direction, is supported by the detector body and has its tip exposed. A drive mechanism that drives the rod to move back and forth in the moving direction of the probe, a communication hole formed in a portion along the tip of the release rod of the detection device main body, and a release hole that is disposed so as to penetrate the communication hole. An engaging mechanism for engaging the release rod and the measuring element when the rod moves in the backward direction of the measuring element, and a case for integrally covering and sealing the release rod or the engaging mechanism. And wherein the door.

Here, the drive mechanism is a cylinder fixed to the main body of the detection device and having an axis set parallel to the moving direction of the probe, and a cylinder movably arranged in the cylinder and of the release rod. A piston having a base end connected thereto is preferable.

[0024]

[Operation] In the present invention as described above, in the measurement, when the probe contacts the object to be measured at the distal end side and moves to the proximal end side, the engagement mechanism causes the engagement between the release rod and the probe. Since the adjustment is canceled appropriately, the tracing stylus can perform normal measurement. Then, by moving the release rod to the proximal end side of the measuring element by the drive mechanism, the release rod engages with the measuring element via the engaging mechanism, and the measuring element is moved to the proximal end side together with the release rod. become. Further, by moving the release rod to the tip side of the tracing stylus by the drive mechanism, the tracing stylus moves to the tip side with the movement of the release rod via the engagement mechanism. Therefore, the tracing stylus can be moved by remote control as in the conventional case, and good operability can be obtained.

On the other hand, in the present invention, since the release rod of the drive mechanism and the tracing stylus are engaged with each other through the engagement mechanism which can be directly released, the conventional mechanical portion such as the slide plate is eliminated. Therefore, the structure can be simplified. In addition, the release rod or the engagement mechanism is integrally covered with the case and hermetically sealed to ensure high dust resistance, and the case is downsized by simplifying and downsizing the structure of the drive mechanism part as described above. You can do it. Therefore, the simplification of the structure and the securing of the dustproof property are realized while obtaining the good operability by these, and thus the above-mentioned object is achieved.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the displacement detecting device 10 of the present embodiment.
Has a cylindrical main body 101, a movable tip 110 is installed on the tip side of the main body 101, and a detection mechanism 120 for detecting the movement amount of the probe 110 is built in on the base end side of the main body 101. On the surface of the middle part of the main body 101,
20 are installed. Of these, the main body 101, the probe 110,
The detection mechanism 120 is the same as the conventional example of FIG. 7 described above, and for the sake of simplification, the description thereof will be omitted here, and hereinafter, the tracing stylus moving mechanism 20 which is a part different from the conventional one will be described.

The tracing stylus moving mechanism 20 has a case 21 fixed to the main body 101, and the case 21 is a guide hole of the main body 101.
It is installed so as to cover 117 and has a communication hole 22 corresponding to the guide hole 117. Further, a drive mechanism 30 is connected and fixed to the base end side surface of the case 21.

The drive mechanism 30 comprises an intermediate block 31 connected to the case 21, and a cylinder case 32 connected in a sealed state to the base end side of the intermediate block 31. A piston 33 is housed in the cylinder case 32, and the piston 33 is movable in the axial direction parallel to the detector 110.
A release rod 34 is connected to the tip end side of the piston 33,
The release rod 34 penetrates the intermediate block 31 and extends into the case 21. A tip member 35 is attached to the tip of the release rod 34, and a contact pin 36 is attached to the tip member 35.
Has been planted. The contact pin 36 is projected into the guide hole 117 through the communication hole 22 and is normally in contact with the guide pin 116 of the spindle 111 which is biased toward the tip side.

A cylinder case 32 is provided on the base end side of the piston 33.
A compression coil spring 37 is interposed between the compression coil spring 37 and the inner surface of the base end of the piston 33. The piston 33 is urged toward the tip side of the main body 101 by the coil spring 37, and the release rod 34 and the contact pin 36 also contact the main body 10.
It is urged toward the tip side of 1, and is held at a fixed position even when the spindle 111 and the guide pin 116 move to the base end side due to the movement of the object to be measured and the mutual contact is released. It is like this. These tip members 35,
The abutment pin 36, the compression coil spring 37, and the guide pin 116 constitute the engagement mechanism 38, and when the release rod 34 moves in the proximal direction, that is, in the backward direction of the probe 110, the release rod 34 and the probe 110 are separated from each other. It is adapted to be engaged.

As shown in FIG. 2, the piston 33 has a piston member 41 which is clamped and fixed to the base end of the release rod 34, and a ring-shaped lip type between both flanges of the piston member 41. The seal member 42 is fitted.
The lip of the seal member 42 is directed toward the tip side, and the piston 33
When a pressure is applied to the tip end of the cylinder, it is set so as to make sliding contact with the inner circumference of the cylinder case 32 while maintaining a high sealing property.

A protrusion 43 is formed on the tip side surface of the intermediate block 31 coaxially with the release rod 34, and the intermediate block 31 presses the protrusion 43 into an opening 44 of the case 21 to press the case 21.
Is combined with. The entire circumference between the protrusion 43 and the opening 44 is hermetically sealed.

A protrusion 46 is formed on the base end side of the intermediate block 31 coaxially with the release rod 34, and the intermediate block 31 is formed by screwing the protrusion 46 into the inner circumference of the opening of the cylinder case 32. Is combined with. A sealing agent or the like is applied to the threaded portion of the protrusion 46, and the cylinder case 32
The inner circumference of the opening is hermetically sealed so as to be airtight.

A vent hole 51 is formed on the end face of the base end side protrusion 46 of the intermediate block 31 toward the tip side along the release rod 34, and a vent hole formed from the upper surface of the intermediate block 31 at the tip part thereof. 52 are in communication.

An inlet pipe 53 is connected to the vent hole 52, and compressed air is supplied to the inlet pipe 53 by a tube 54 from an external compressed air supply device (not shown). Where the tube
Compressed air supplied from 54 is introduced from the introduction pipe 53 to the ventilation holes 52,
The pressure chamber 55 between the front end side of the piston 33 and the pressure chamber 55 is filled via 51, whereby the piston 33 is moved to the base end side. Further, the compressed air in the pressure chamber 55 is introduced from the vent holes 51 and 52 by exhausting the compressed air from the tube 54 with the compressed air supply device.
After being discharged through 53, the piston 33 is moved to the tip side by the above-mentioned compression coil spring 37.

A cylindrical ventilation adjusting member 56 coaxially arranged with the release rod 34 is inserted into the ventilation hole 51. A male screw portion 57 is formed in a partial region on the outer circumference of the ventilation adjusting member 56, and the male screw portion 57 is formed on the inner circumference of the ventilation hole 51 over a predetermined length from the base end side opening portion to the female screw portion 58. Is screwed to. As a result, the air passing through the ventilation hole 51 is throttled through the gap between the male screw portion 57 and the female screw portion 58, and the flow velocity is suppressed. In addition, ventilation adjustment member
A flange 59 is formed on the proximal end of 56, and this flange
The reference numeral 59 also serves as a stopper that comes into contact with the piston 33 and restricts movement toward the tip side.

In this embodiment having such a configuration, various operations are performed by the following operations. Normally, by not supplying compressed air into the pressure chamber 55,
The piston 33 and the release rod 34 are compression coil springs 37.
Is maintained at the forward limit of the tip side. And the probe 11
0 is biased toward the tip side by the compression coil spring 118, and is maintained at the position where the guide pin 116 is locked by the contact pin 36 (normal state, see FIG. 3).

When performing measurement, the object to be measured is brought into contact with the tip of the probe 110. The contact point 11
0 retreats to the base end side against the compression coil spring 118. Then, the guide pin 116 is separated from the contact pin 36. At this time, the contact point 110 is kept in contact with the object to be measured by the compression coil spring 118, and the contact point 110 undergoes a displacement D corresponding to the contact position of the object to be measured, and this displacement D is detected. Bowl 120
(Measured state, see FIG. 4). In addition, the probe 11
If the object to be measured is removed from the tip of 0, the compression coil spring 11
The stylus 110 is moved forward by 8 and automatically returns to the normal state of FIG.

When the probe 110 is forcibly retracted, compressed air is supplied from the tube 54 to the pressure chamber 55. Due to this supply of compressed air, the piston 33 retracts toward the base end side against the compression coil spring 37, and the release rod 34 and the contact pin 36
Also retreat by the same distance R. As a result, the guide pin 116 abutted and locked by the abutment pin 36 is driven toward the base end side, and the tracing stylus 110 is retracted by the distance R against the compression coil spring 118 (release state, see FIG. 5). .. At this time, the compressed air supplied from the tube 54 to the pressure chamber 55 is throttled by the ventilation adjusting member 56, and the flow velocity of the gas flowing into the pressure chamber 55 is suppressed. There is no shock or the like caused by a sudden motion.

When releasing the release, the compressed air in the pressure chamber 55 is discharged from the tube 54. Due to the discharge of the compressed air, the piston 33 is moved forward by the compression coil spring 37, and the release rod 34 and the contact pin 36 are also moved forward integrally. As a result, the guide pin 116, which has been abutted and locked by the abutment pin 36, can be moved to the distal end side, and the tracing stylus 110 is advanced by the compression coil spring 118 and returns to the normal state of FIG. 3 (release release state). , See FIG. 6). Even at this time, the compressed air discharged from the pressure chamber 55 to the tube 54 is throttled by the ventilation adjusting member 56, and the outflow velocity from the pressure chamber 55 is suppressed, so that the piston 33 is slowly moved forward and measured. A shock or the like due to a sudden motion is not generated in the child 110 or the like.

In each state, the probe 110, the guide pin 116, the contact pin 36, the release rod 34, etc., which are the operating parts, are sealed by the main body 101 and the case 21 and are shielded from the outside, so that oil and dust are not present. Etc. will not enter.

According to this embodiment as described above, there are the following effects. That is, when measuring,
When 110 contacts the object to be measured at the tip side and moves to the base end side, the engagement mechanism 38 by the contact between the contact pin 36 and the guide pin 116 engages the release rod 34 and the probe 110. Is appropriately released, so that the tracing stylus 110 moves to the tracing stylus moving mechanism 20.
Regardless, the usual measurement can be performed.

By driving the piston 33 of the drive mechanism 30 with compressed air, the release rod by the engagement mechanism 38 is driven.
34 and the contact point 110 are engaged with each other, and the contact point 110 can be retracted (released) together with the release rod 34 toward the base end side or advanced toward the tip end side (release release). Therefore, by the operation of supplying or discharging compressed air,
The contact point 110 can be released and released by remote control, and good operability can be obtained as in the conventional case.

At this time, in the present embodiment, the contact pin 36
Further, since the release rod 34 and the tracing stylus 110 are directly engaged with each other through the engaging mechanism 38 by the contact of the guide pin 116, the conventional mechanical portion such as the slide plate is eliminated and the structure is simplified. Can be converted.

The case 21 can be miniaturized by simplifying the structure of the portion from the tracing stylus 110 to the driving mechanism 30 such as the release rod 34 via the engaging mechanism 38, and the tracing stylus moving mechanism 20 and thus the displacement can be realized. The detection device 10 can be made compact and lightweight.

Further, the release rod 34 or the engagement mechanism
Since 38 is integrally covered and sealed by the case 21,
It is possible to secure high dust resistance against oil and dust from the outside.
Therefore, high accuracy and reliability can be ensured for a long period of time even when used for in-line measurement in a manufacturing process or the like.

Further, in the drive mechanism 30 of this embodiment,
A ventilation adjusting member 56 is provided in the passage of compressed air for driving the piston 33, and the flow of compressed air is restricted by passing through the gap between the male screw portion 57 and the female screw portion 58 to suppress the flow velocity. 33 or probe
The movement of 110 can be slowed down. For this reason, it is possible to prevent an impact or the like on the detector 120 or the like that requires high accuracy, and also in this respect, the accuracy and reliability can be maintained for a long time.

The present invention is not limited to the above embodiments, but the following modifications and the like are included in the present invention. For example, the shape and material of the main body 101, the case 21, the intermediate block 31, and the cylinder case 32, the mounting position and shape, the shape of the communication hole 22 that connects the inside of the case 21 and the inside of the main body 101, and the like may be appropriately selected for implementation. In short, it suffices that the engaging mechanism 38 reaching the main body 101 or the drive mechanism 30 and the mechanical parts such as the release rod 34 can be integrally sealed in a communicating state.

Further, the measuring element 110 in the displacement detecting device 10
The specific structure, format, specifications, etc. of the detector 120 are not limited to those in the above-described embodiment, and may be appropriately selected. Further, the specific structure and type of the release rod 34 and the drive mechanism 30 in the tracing stylus moving mechanism 20 may be appropriately selected. The structure of the piston 33 in the drive mechanism 30, the flow path form of the compressed air in the intermediate block 31, the take-out form of the tube 54, etc. are not limited to those in the above-described embodiment, and may be appropriately selected.

In particular, although the drive mechanism 30 which moves forward and backward by compressed air is used in the above embodiment, the forward movement when the compressed air is released is not limited to the compression coil spring 37 and the like, but other types of springs, magnetic forces, pistons, etc. Alternatively, compressed air may be supplied to the base end side of 33. Alternatively, the drive is not limited to the drive by compressed air, and other drive such as electromagnetic force may be performed, and a manually operated release mechanism or the like may be used as long as the wire protrudes by an operation.

Further, the concrete structure of the engagement structure 38 is also arbitrary, and the attachment structure and the engagement state of the contact pin 36 of the release rod 34 and the guide pin 116 of the probe 110 may be selected as appropriate, and the rotation can be performed. The engagement may be performed by using a portion other than the guide pin 116 of the stopper.

[0051]

As described above, according to the present invention, the feeler and the release rod are directly disengaged from each other, and these mechanical portions are integrally covered, whereby the operability by remote operation is improved. It is possible to improve the dustproof property while simplifying the structure, and to simplify the structure.

[Brief description of drawings]

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

FIG. 2 is an enlarged cross-sectional view showing a main part of the embodiment.

FIG. 3 is a schematic view showing a normal state of the embodiment.

FIG. 4 is a schematic diagram showing a measurement state of the embodiment.

FIG. 5 is a schematic view showing a release state of the embodiment.

FIG. 6 is a schematic view showing a release release state of the embodiment.

FIG. 7 is a sectional view showing a conventional example.

[Explanation of symbols]

 10 Displacement detecting device 20 Measuring element moving mechanism 21 Case 22 Communication hole 30 Drive mechanism 33 Piston 34 Release rod 36 Abutment pin 38 Engaging mechanism 56 Ventilation adjusting means 101 Main body 110 Measuring element 116 Guide pin 120 Detector

Claims (2)

[Claims] 1. A measuring element relating to an object to be measured, a detecting device body for slidably supporting the measuring element, and a detector installed in the detecting device body for detecting a moving amount of the measuring element. Attached to a displacement detecting device, for moving the tracing stylus in a desired direction, a release rod supported at the sensing device main body and having a tip exposed is a moving direction of the tracing stylus. Drive mechanism for moving forward and backward, a communication hole formed in a portion along the tip of the release rod of the detection device main body, and a release rod arranged so as to penetrate the communication hole in the retracting direction of the probe. Displacement detection characterized by comprising an engaging mechanism for engaging the release rod and the tracing stylus when moved, and a case for integrally covering and sealing the release rod or the engaging mechanism. Location of the measurement piece moving mechanism. 2. The measuring element moving mechanism of the displacement detecting device according to claim 1, wherein the drive mechanism is fixed to the detecting device main body, and an axis thereof is set parallel to a moving direction of the measuring element. And a piston which is movably arranged in the cylinder and to which a base end portion of the release rod is connected, and a tracing stylus moving mechanism of a displacement detecting device.