JP6983588B2 - Measuring instrument, collision evacuation mechanism used for it, and collision evacuation method - Google Patents

Description

The present invention relates to a measuring instrument for measuring the inner diameter and the like, a collision evacuation mechanism used thereof, and a collision evacuation method, and particularly suitable for a measuring instrument for automatically and continuously measuring, a collision evacuation mechanism used thereto, and a collision evacuation method. Regarding.

In machine tools such as machining centers, it is generally adopted to automate the measurement of the machined portion of the workpiece after machining for the purpose of unmanned operation or labor saving. For example, using an autochanger, the measuring instrument is automatically attached to the spindle portion to which the tool is attached, and the measuring tool is automatically moved to the machining position according to a pre-programmed procedure. At that time, since unmanned measurement is the principle, it is necessary to assume that the measuring instrument will unintentionally touch or collide with the work or the holding means for holding the work for some reason. Patent Document 1 describes such an example in which the measuring instrument is quickly retracted (released) to protect the measuring instrument when the measuring instrument collides with a work or the like.

In Patent Document 1, in order to provide a measuring head safety mechanism for an inner diameter measuring instrument that can avoid damage to the measuring head at the time of a collision, the inner diameter measuring instrument is housed in a casing while being held by a holder. .. Then, the holder is pressed against the pedestal attached to the tip of the casing by a tension spring. When the measuring head receives a collision from the front, the holder retracts from the pedestal against the urging force of the tension spring, thereby avoiding damage to the measuring head due to the impact of the collision.

Japanese Unexamined Patent Publication No. 2000-337806

In the measuring head structure described in Patent Document 1, the measuring machine main body integrated with the measuring head is held in a holder, and the entire holder is loosely fitted in a cylindrical casing. Then, the other end side of the spring whose one end side is fixed to the casing is attached to the loosely fitted holder, and the tensile force of the spring is applied in the axial direction. Further, the positioning in the circumferential direction and the radial direction is determined by the connected state of the three contacts in the circumferential direction formed on the plane perpendicular to the axis of the holder.

In the measurement head described in this publication, once the measurement head comes into contact with the edge of the hole to be measured, the entire holder moves in the axial direction against only the spring force, so that quick evacuation requiring only a small force is required. You can expect the operation. However, since the holding force of the holder is small, it is considered to be an effective method when the holder is lightweight or short, but when the holder is long or heavy, high-speed auto tool change becomes difficult.

That is, in the retracting operation of the measuring head, the entire holder moves against the spring force, so that a force acts in the vertical direction on the axis of the measuring head due to the collision, and the entire holder is displaced in the direction in which the force acts as well as the axial direction. do. When the collision force is lost after such displacement in the collision evacuation operation, the restoring force acts on the entire holder due to the tensile spring force. By the way, when a large acceleration is applied to the holder, the holder may be lifted diagonally due to the influence of inertial force. In that case, it becomes difficult to hold the holder, and erroneous detection may occur. This phenomenon becomes more remarkable as the length of the holder becomes longer and heavier, and in the worst case, the auto tool change cannot be executed. Further, if the shape of the contact is changed due to wear or the like, the contact state of the contact naturally changes, and the initial positioning cannot be achieved.

In order to solve this problem, it is conceivable to support the axial movement of the measuring head with a bearing. For example, when the measuring head is supported by a rolling bearing, the support part of the measuring head should be supported in order to withstand the impact of the measuring head at the time of collision and to prevent the measuring head from vibrating when it comes into contact with the hole at the time of measuring. It is necessary to increase the rigidity including, and the rolling bearing becomes large. This causes the measuring head itself to become large and the measuring instrument to become expensive. Further, when the measurement head is supported by a slide bearing, a bearing gap is required in the slide bearing, and this gap becomes rattling, which causes a measurement error even in normal measurement.

The present invention has been made in view of the above-mentioned defects of the prior art, and an object of the present invention is to promptly change the measuring instrument without damaging the measuring instrument even if an abnormal event such as a collision with a measuring object or the like occurs. The measuring instrument is retracted from the place where the event occurred, and at the same time, in the measurement after the retracting, the measuring instrument is accurately restored to the original position, and the measuring instrument is restored with high accuracy without causing tilting or eccentricity. It is to enable measurement.

A feature of the present invention for achieving the above object is a measuring instrument for measuring at least one of an inner diameter, an outer diameter, a depth and a thickness of an object to be measured, wherein the measuring instrument is a measuring unit having a stylus. It is provided with a sensor probe unit having a detection unit arranged close to the measurement unit, and a collision evacuation mechanism which is a portion extending in the axial direction of the sensor probe unit and is attached to the sensor probe unit. The collision evacuation mechanism has an inner tapered shaft and an outer tapered shaft having a nested structure, and each of the inner tapered shaft and the outer tapered shaft has a tapered locking portion provided in an intermediate portion and this tapered locking portion. It is to have a large-diameter and small-diameter cylindrical portion provided on both axial end sides of the portion.

In this feature, it is preferable that the large-diameter and small-diameter cylindrical portions of the inner tapered shaft and the large-diameter and small-diameter cylindrical portions of the outer tapered shaft face each other, and each of them is configured as a slide bearing. The tapered shaft is formed in an enlarged tubular shape, and a base plate is attached to the large diameter side of the expanded tubular, while the inner tapered shaft is also formed in an enlarged tubular shape, and the large diameter side of the base plate and the inner tapered shaft. It is desirable to dispose a compression spring between the and, and to urge the sensor probe portion so as to be axially separated from the collision evacuation mechanism during normal use.

Further, in the above characteristics, a relief portion extending in the axial direction is provided at the connection portion between the tapered locking portion and the small diameter cylindrical portion of the inner tapered shaft and the connecting portion between the tapered locking portion and the large diameter cylindrical portion of the outer tapered shaft. A switch having a contact connected to the sensor probe portion and a contact connected to the base plate is provided, and a signal for stopping the axial movement of the measuring instrument by the operation of the switch is sent to this measuring instrument. It may be possible to transmit to a control unit such as a machine tool to which is attached.

Another feature of the present invention that achieves the above object is that the sensor / probe portion is attached to the sensor / probe portion of the measuring instrument, and when the sensor / probe portion comes into contact with or collides with a work or the like, the sensor / probe portion is moved in the axial direction thereof. In the collision evacuation mechanism that retracts from the contact or collision position, it has an inner tapered shaft and an outer tapered shaft of a nested structure, and each of the inner tapered shaft and the outer tapered shaft is a tapered locking portion provided in an intermediate portion. And this tapered locking portion has large and small diameter cylindrical portions provided on both axial end sides, and the locking portion of the inner tapered shaft and the locking portion of the outer tapered shaft are in a normal state. The large-diameter and small-diameter cylindrical portions of the inner tapered shaft and the large-diameter and small-diameter cylindrical portions of the outer tapered shaft are substantially in close contact with each other and locked, and the sliding bearing is provided during the retracting operation. To form.

Yet another feature of the present invention that achieves the above object is a tapered locking portion attached to the sensor probe portion of the measuring instrument and provided in the intermediate portion, and both axial ends of the tapered locking portion. A collision evacuation mechanism equipped with a nested inner and outer tapered shafts and compression springs disposed between the inner and outer tapered shafts having large and small diameter cylindrical portions provided on the side. In the method used, when the sensor / probe portion comes into contact with or collides with an external object such as a work, the large-diameter and small-diameter cylindrical portions of the inner tapered shaft and the large-diameter and small-diameter cylindrical portions of the outer tapered shaft facing each other. Form a sliding bearing to retract the inner tapered shaft axially toward the outer tapered shaft, and when the sensor probe does not contact or collide with an external object, the compression spring expands and the inner tapered shaft is extended. The shaft is urged so as to be separated from the outer tapered shaft in the axial direction, and the tapered locking portion of the inner tapered shaft is substantially brought into close contact with the tapered locking portion of the outer tapered shaft. be.

According to the present invention, since the measuring instrument is provided with a shaft having slide bearing portions at both ends of the tapered shaft, even if an abnormal event such as the measuring instrument colliding with a measuring object or the like occurs, the measuring instrument is not damaged. It can be quickly evacuated from the place where the event occurred. Further, in the return measurement after retracting, since the measurement head is moved in the axial direction using the taper axis as a guide, highly accurate measurement can be performed without causing tilting or eccentricity of the measuring instrument.

It is a front view of the Example of the measuring apparatus which attached the measuring instrument which concerns on this invention. It is an exploded view of an Example of the collision evacuation mechanism of the measuring instrument which concerns on this invention. FIG. 3 is a partial cross-sectional view of a measuring instrument for explaining the operation of the collision evacuation mechanism shown in FIG. 2. It is a figure explaining the operation of the collision evacuation mechanism shown in FIG. It is sectional drawing which shows an example of the measuring head of a measuring instrument.

Hereinafter, examples of the measuring instrument according to the present invention and the collision evacuation mechanism used thereof will be described with reference to the drawings. FIG. 1 is a front view of an embodiment of a machine tool 50 incorporating the measuring instrument 80 according to the present invention, and the measuring instrument 80 is an inner diameter measuring instrument (bore gauge). In this embodiment, the inner diameter measuring instrument is taken up as an example of the measuring instrument 80, but the measuring instrument 80 is not limited to the inner diameter measuring instrument, but the outer diameter measuring instrument, the thickness measuring instrument, the depth measuring instrument, and the contact type. It can be applied to various devices such as 3D measuring instruments, non-contact measuring instruments such as laser heads and cameras, and observation machines.

In the machine tool 50 in which the main body 12 is fixedly installed on the foundation 10, a shank is attached to the spindle portion 16, and a bore gauge (measuring instrument) 80, which is an inner diameter measuring instrument according to the present invention, is attached to the shank. The bore gauge 80 can be moved in the vertical direction together with the spindle portion 16 by the Z-axis driving means 20 including the motor attached to the upper part of the main body 12. A work 40 to be measured is arranged below the bore gauge 80, and is fixedly held on the XY table 30 by the work holding means 36.

In this embodiment of the XY table 30, the upper X-axis table 32 is X-axis driven by the X-axis driving means 22 including the motor, and the lower Y-axis table 34 is X by the Y-axis driving means 24 including the motor. It is driven linearly in the direction (left-right direction in this figure) and the Y direction (vertical direction on the paper surface in this figure). Therefore, by driving the spindle portion 16 to which the bore gauge 80 is attached in the Z direction by the Z-axis drive means 20 and the work 40 in the X and Y directions by the XY table 30, the relative positions of the bore gauge 80 and the work 40 are positioned. Will be done. Or, although not shown, it is also equipped with an Θ table to enable rotational movement.

Here, a control device 14 for controlling the machine tool 50 is arranged at an appropriate position (upper left side in the figure) of the machine tool 50. The control device 14 includes a control unit (control unit) 26 and a display unit 28, and the control unit 26 controls the start / stop of the machine tool 50 and the relative positioning of the measurement hole 42 formed in the work 40 and the bore gauge 80. ..

The display unit 28 displays the current coordinates. The control unit 26 includes a control unit 70 for an inner diameter measuring device that executes control related to the measurement of the bore gauge 80, and the control unit 70 for the inner diameter measuring device and the bore gauge 80 are combined to form the inner diameter measuring device 100.

Next, the details of the bore gauge 80 as the inner diameter measuring instrument according to the present invention will be described in detail with reference to FIGS. 2 to 4. 2 (a) is an exploded view of an embodiment of the bore gauge 80 according to the present invention, and FIG. 2 (b) is a view A in FIG. 2 (a). 3A and 3B are partial vertical cross-sectional views showing a state of the bore gauge 80 in an operating state shown in FIG. 2, FIG. 3A is a view showing a measurement-compatible state, and FIG. 3B is a retracted state. It is a figure. 3 (c) and 3 (d) are enlarged views showing the details of parts _{D 1} and D _{2 of FIG. 3 (a), respectively.} 4A and 4B are diagrams for explaining the transition between the measurement-compatible state and the retracted state of the bore gauge 80, FIG. 4A is a diagram showing a retracted state substantially coaxially, and FIG. 4B is a curved or coaxial diagram. Instead, it is a diagram showing a retracted state, and FIG. 4 (c) is a diagram showing a state of returning to the measurement-compatible state.

Returning to FIG. 2, in the bore gauge 80, the collision evacuation mechanism 200 is provided on the coupling side of the sensor probe portion 110 having the stylus to the spindle portion, which is the anti-measurement side. In the collision evacuation mechanism 200, the inner tapered shaft 230 is fixed to the sensor probe portion 110 by means (not shown). The inner tapered shaft 230 has an outer shape that expands in the axial direction from the sensor probe portion 110 side. That is, the inner tapered shaft 230 is provided with a tapered portion (locking portion) 218 whose outer shape extends in a conical shape from the sensor probe portion 110 side to the open end portion in the axial intermediate portion, and the tapered portion 218 is provided at both ends in the axial direction. A small-diameter cylindrical portion 220 and a large-diameter cylindrical portion 216 are formed in. A key groove 214 is formed at one position in the circumferential direction on the open end side of the inner tapered shaft 230. The keyway 214, the key 212 is fitted from the radially outer side as shown by an arrow B _1.

Inside the inner tapered shaft 230, through holes are formed with a plurality of steps, and the smallest diameter hole passes through an axially extending strut 222 that supports the base 226 that holds the contact 228 of the switch 280. It is a through hole portion 236 for making it. One end of the lead wire 224 is connected to the switch 280, and it is used to transmit the switch 280 signal to the control unit (control unit) 26 included in the machine tool 50 such as a machining center to which the measuring instrument 80 is attached.

In FIG. 2 of the through hole portion 236, a spring fitting hole portion 234 having an outer diameter larger than that of the through hole portion 236 is formed on the left side, and a spring holding hole portion 232 having a larger diameter is further formed on the left side. It is formed. The spring fitting hole portion 234 is for positioning and holding the end portion of the compression spring 262, preventing the spring 262 from being held eccentrically and preventing the spring 262 from falling off from the inner tapered shaft 230. do. The spring holding hole portion 232 holds the spring 262 in the inner tapered shaft 230 and acts as a gap for absorbing a slight increase in the outer diameter of the spring 262 when the spring 262 is displaced in the axial direction.

The outer cylindrical outer tapered shaft 250 having a tapered portion (locking portion) 256 corresponding to the tapered portion (locking portion) 218 of the inner tapered shaft 230 on the inner diameter side has a small inner surface on the inner surface of the cylinder. The cylindrical portion 254 made of the above has a cylindrical portion 258 having an inner surface of the cylinder having a large inner diameter on the side of the large diameter end portion. A keyway 260 corresponding to the keyway 214 of the inner tapered shaft 230 is formed at one position in the circumferential direction of the inner surface of the large-diameter cylinder, enabling smooth fitting of the key 212. The key 212 acts as a detent to prevent the outer taper shaft 250 from being displaced circumferentially with respect to the inner taper shaft 230.

An oil seal holding hole 252 for holding the oil seal or the lip seal 240 is formed on the minimum inner diameter side of the outer taper shaft 250. Oil seal 240 is fitted to the oil seal holding hole portion 252 in the axial direction as shown by an arrow B _2. A disk-shaped base plate 270 that closes the shaft end of the outer tapered shaft 250 is fastened to the leftmost end of the outer tapered shaft 250 using a fastener (not shown). A through hole 272 is formed in the center of the base plate 270, and a lead wire 224 whose one end side is electrically connected to the contact 228 of the switch 280 can pass through the through hole 272. .. A spring fitting hole 268 for holding the other end side of the spring 262 is formed on the inner surface side (right side in FIG. 2) of the base plate 270. The spring fitting hole 268 prevents the spring 262 from falling off the base plate 270. The fitting hole 268 and the fitting hole portion 234 prevent the spring 262 from falling off from each of the inner tapered shaft 230 when the inner tapered shaft 230 is displaced in the axial direction with respect to the outer tapered shaft 250, and the urging force of the spring 262. Works along the central axis of the outer tapered shaft 250 and the inner tapered shaft 230.

The collision evacuation operation of the measuring instrument 80 configured in this way will be described with reference to FIGS. 3 and 4. FIG. 3A is a diagram showing a state in which the measuring instrument 80 is brought close to the workpiece 40 to be measured in order to start the measurement in a state where the measuring instrument 80 is attached to a machine tool or the like (not shown). A compression spring 262 is attached between the outer taper shaft 250 and the inner taper shaft 230, and the urging force of the compression spring 262 acts in the axial direction to cause the inner taper shaft 230 attached to the sensor probe portion 110. The tapered portion 218 of the outer tapered shaft 250 is urged to be pressed against the tapered portion 256 of the outer tapered shaft 250. As a result, the evacuation stroke st is formed between the spring mounting side end surface 242 of the inner tapered shaft 230 and the end surface 244 of the base plate 270.

At this time, the inner tapered shaft 230 and the outer tapered shaft 250 are substantially in close contact with each other at the tapered portions 218 and 256, respectively. In this embodiment, stainless steel SUS304 is used for the inner tapered shaft 230 and the outer tapered shaft 250. Since the inner taper shaft 230 and the outer taper shaft 250 are made of the same material, there is a possibility that galling, friction, or the like may occur due to sliding. In order to prevent such a problem, grease is applied to the outer peripheral surface of the inner tapered shaft 230 and the inner peripheral surface of the outer tapered shaft 250. Therefore, the fact that the tapered portions 218 and 256 are in close contact with each other also includes contact via the grease film. Since grease is applied to each of the inner taper shaft 230 and the outer taper shaft 250, an oil seal or lip seal 240 is attached to one end surface of the outer taper shaft 250 to prevent the grease from flowing out to the outside. ing.

When the measuring instrument 80 is brought close to the workpiece 40 to be measured in the state of FIG. 3A and inserted into the measuring hole, the stylus 81a and 81b are extended outward in a direction perpendicular to the axis of the sensor probe portion 110 to reduce the inner diameter. Measure. At that time, in the collision evacuation mechanism 200, the tapered portions 218 and 256 of the inner tapered shaft 230 and the outer tapered shaft 250 are in contact with each other, and the end face 242 of the inner tapered shaft 230 and the end face of the base plate 270 attached to the outer tapered shaft 250 are in contact with each other. As described above, the evacuation stroke st is formed between 244.

Incidentally, when to close the work the instrument 80 in the state of FIG. 3 (a), when accidentally the edges or the like of the measurement hole of the work by colliding C ₁ becomes the state of FIG. 3 (b), the sensor probe portion Since the stylus 81a and 81b of the 110 do not exceed the outer diameter of the sensor probe portion 110, they are protected from collision, but the sensor probe portion 110 may be damaged. Therefore, the sensor / probe unit 110 is quickly retracted from the work 40 in the axial direction.

That is, the inner tapered shaft 230 connected to the sensor probe portion 110 receives a reaction force from the work 40 due to the collision C1, and the urging force of the compression spring 262 interposed between the inner tapered shaft 230 and the outer tapered shaft 250. It moves to the left side in FIG. 3 and is displaced to the maximum position before the retract stroke st.
In this way, the position before the evacuation stroke st is to allow for a safety margin until the machine tool stops, and when the machine tool is retracted to the evacuation stroke st, the impact of the collision immediately after that is the bore gauge and the work. This is because it is transmitted to the spindle of the machine and may cause damage to the bore gauge.
For example, if the evacuation stroke st is 5 mm, it is preferable that the contacts 228 and 266 of the switch 280 come into contact with each other to detect a collision when the stroke is about 0.3 mm. As a result, the remaining stroke can be used as a safety margin from the detection of the collision to the actual stop. Therefore, even if the switch 280 moves a little after detecting the contact until it actually stops, it can stop at a position before the evacuation stroke st. At this time, a gap is formed between the inner diameter side of the outer taper shaft 250 and the outer diameter side of the inner taper shaft 230.

Since the inner taper shaft 230 moves so as to reduce the axial distance with respect to the outer taper shaft 250, the contacts 228 and 266 of the switches 280 provided in each move in contact with each other to electrically detect the collision. The detected collision is transmitted to the control unit 26 included in the machine tool 50 via the lead wire 224, and the machine tool 50 immediately stops the movement of the entire measuring instrument 80, that is, the spindle unit to the work 40. As a result, the inner taper shaft 230 finishes the collision withdrawal operation before the end face 242 of the inner taper shaft 230 comes into contact with the end face 244 of the base plate 270 of the outer taper shaft 250, that is, before the entire stroke of the retract stroke st is moved. do.

The details of collision evacuation will be described with reference to FIG. 4 (a). FIG. 4A is a schematic view showing a state in which the collision evacuation mechanism is operated. The gaps and the like are exaggerated to facilitate understanding. As described above, the inner taper shaft 230 is not always displaced by the maximum stroke st, and in many cases, the displacement is stopped in the middle due to the operation of the switch 280. In the collision evacuation operation, the inner tapered shaft 230 and the outer tapered shaft 250 release contact or disengagement at the respective tapered portions (locking portions) 218 and 256, and the large and small diameter cylindrical portions 216 and 220, respectively. A plain bearing having gaps 304 and 306 is formed between 258 and 254.

That is, in the collision evacuation operation, the slip lubricated with grease having a gap 306 between the outer peripheral surface of the small diameter cylindrical portion 220 of the inner tapered shaft 230 and the inner peripheral surface of the small diameter cylindrical portion 254 of the outer tapered shaft 250 facing the inner peripheral surface. A bearing and a grease-lubricated slide bearing having a gap 304 between the outer peripheral surface of the large-diameter cylindrical portion 216 of the inner tapered shaft 230 and the inner peripheral surface of the large-diameter cylindrical portion 258 of the outer tapered shaft 250 facing each other. , Each form. As a result, when an unexpected event such as a collision of the measuring instrument 80 occurs, the inner tapered shaft 230 is quickly retracted by using the slide bearing as a guide in the direction opposite to the moving direction of the measuring instrument 80. Since it has a slide bearing, there is almost no resistance due to retracting, and it is sufficient that only a force that opposes the spring 262 is generated by the collision. At this time, the gap 302 between the outer peripheral surface of the tapered portion 218 of the inner tapered shaft 230 and the inner peripheral surface of the tapered portion 256 of the outer tapered shaft 250 is rapidly increased from the gaps 304 and 306 of the bearing portion due to the displacement of the inner tapered shaft 230. Since it becomes large, it does not become a resistance when the inner taper shaft 230 is displaced.

Since the cylindrical portions 216, 220; 254 and 258 of the inner tapered shaft 230 and the outer tapered shaft 250 may act as bearings, the gaps 304 and 306 between them should be appropriate gaps as a slide bearing. Since a normal sliding bearing is designed to form a gap of several percent or less of the diameter of the supporting shaft, the gaps 304 and 306 are made as small as possible within the above range in this embodiment as well. The gaps 304 and 306 are necessary to quickly retract the inner taper shaft 230, that is, the sensor probe portion 110, but when the measurement state is entered while the gap is maintained, the gaps 304 and 306 become the measuring instrument 80. The rigidity of the sensor is reduced, and measurement errors are likely to occur. Therefore, as described above, at the time of measurement, the tapered portions 218 and 256 are brought into close contact with each other substantially directly to eliminate a gap between the inner tapered shaft 230 and the outer tapered shaft 250.

Returning to FIG. 3, FIG. (C), (d) is an enlarged view of a _{D 1} part and _{D 2} parts of FIG. 3 (a). FIG. 3C is a diagram showing a portion of the inner tapered shaft 230 and the outer tapered shaft 250 that transition from the large-diameter side cylindrical portions 216 and 258 to the tapered portions 218 and 256, respectively. A concave surface is formed at the boundary portion from the cylindrical portion 258 to the tapered portion 256. Generally, when a concave surface is formed by turning or the like, the influence of the cutting edge R remains at the boundary after machining (because of the radius R of the cutting edge, the machining of the angled part leaves a mark of the cutting edge radius R). .. The influence of the blade tip R interferes with the corner of the boundary from the cylindrical portion 216 to the tapered portion 218 of the corresponding inner tapered shaft 230. Therefore, the cylindrical portion 258 of the outer tapered shaft 250 is extended in the axial direction to the tapered portion 256 side, and a relief portion 290 is formed at the connecting portion between the cylindrical portion 258 and the tapered portion 256. This avoids interference between the inner taper shaft 230 and the outer taper shaft 250.

Even at the transition portion from the tapered portion 218 of the inner tapered shaft 230 to the cylindrical portion 220 having a small diameter, a concave portion on the outer surface, that is, a corner portion having a cross-sectional shape of less than 180 ° is formed, so that interference due to the cutting tool R due to turning is prevented. Therefore, the cylindrical portion 220 is extended in the axial direction at the portion, and a relief portion 292 is formed at the connection portion between the cylindrical portion 220 and the tapered portion 218. This avoids interference between the inner taper shaft 230 and the outer taper shaft 250.

Proceeding to FIG. 4, FIGS. 4A and 4B are views in which the collision evacuation mechanism 200 is operated, and in FIG. 4A, the inner tapered shaft 230 is the longitudinal axis of the measuring instrument 80 using the above-mentioned bearing. This is the case when the evacuation is carried out almost along the line. On the other hand, since the contrasting operation of the inner tapered shaft 230 is a momentary operation, it is assumed that the inner tapered shaft 230 tilts or eccentricly retracts within the range of the bearing gap due to the collision state between the measuring instrument 80 and the work 40. Will be done. FIG. 4B shows an example of such misalignment and evacuation. The central axis of the inner tapered shaft 230 no longer coincides with the central axis of the outer tapered shaft 250.

The result of extending the compression spring 262 for measurement from such a state is shown in FIG. Although the inner tapered shaft 230 is tilted within the range of the bearing gap at the time of retracting, the tapered portion 218 of the inner tapered shaft 230 and the tapered portion 256 of the outer tapered shaft 250 serve as a guide when the compression spring 262 is extended, and the tilt of the inner tapered shaft 230 is tilted. After being corrected, the tapered portions (locking portions) 218 and 256 are substantially in close contact with each other in a state where the axial center of the outer tapered shaft 250 is finally aligned with the axial center. This makes it possible to prevent the occurrence of measurement error during measurement due to bending or misalignment of the axis of the measuring instrument 80.

An example of the sensor probe portion 110 of the bore gauge (measuring instrument) 80 used in the machine tool 50 shown in FIG. 1 is shown in FIG. This figure is a partial cross-sectional front view of the sensor probe portion 110, and the upper part is omitted. The sensor probe unit 110 is for measuring the inner diameter. In FIG. 5, only the left side portion is shown in a cross-sectional view, but the same applies to the right side portion, so the description of the right side portion will be omitted. Therefore, for the right part, the subscript a of each part in the description of the left part may be replaced with b.

The sensor probe portion 110 has an outer diameter corresponding to the inner diameter of the measurement hole (or hollow portion) 42 of the work 40, and the transducers 81a and 81b described later are provided below the outer diameter so as to be movable in the radial direction. It has a long extending measuring unit 78 on the lower side of the cylindrical shape. Above the measuring unit 78, an inner diameter detecting unit 79 that converts the amount of movement of the stylus 81a and 81b into an electric signal is provided.

That is, the measuring arm 82a extends downward long along the axis of the sensor probe portion 110, and is rotatably supported by the fulcrum 83a arranged in the detection portion 79. A stylus 81a having a cylindrical shape and a hemispherical tip thereof is provided in the vicinity of one tip of the measuring arm 82a, and the axis of the stylus 81a is the measuring arm 82a. It is installed at right angles to the extending direction of. However, if the displacement in the direction orthogonal to the central axis of the sensor / probe portion 110 can be measured, the sensor / probe portion 110 may be mounted at an angle. The other end of the measuring arm 82a is a detecting arm 84a, and the detecting arm 84a extends in a direction substantially perpendicular to the axial direction of the measuring arm 82a in order to increase the displacement of the stylus 81a. There is.

A displacement detector 86a such as a linear sensor having a displacement member 85a at the tip thereof is disposed substantially facing and above the tip of the detection arm 84a. A support column 93a is arranged above the fulcrum 83a of the detection arm 84a. The support column 93a is connected to a support column 94a provided on the lower surface side of the base 87 constituting the outer shape of the detection unit 79 of the sensor probe unit 110 via a spring 88. A displacement detector 86a is attached to the lower surface of the base 87 in addition to one end of the support column 94a.

The outer peripheral sides of the measuring unit 78 and the detecting unit 79 are protected by a bottomed protective member 92. The bottom of the protective member 92 is configured to have a diameter larger than the outer diameter at the position where the stylus 81a and 81b are arranged. When positioning the sensor / probe unit 110 in the work 40, the stylus 81a and 81b are retracted inside the sensor / probe unit 110. As a result, it is possible to prevent unintended contact with an external object of the sensor / probe portion 110 due to the stylus 81a and 81b being located on the outer diameter side beyond the bottom diameter.

In the above embodiment, the lever type inner diameter measuring instrument has been described as an example, but the inner diameter measuring instrument is not limited to this, and various types can be used. Furthermore, the measuring instrument is not limited to the inner diameter measuring instrument, but is a contact type or non-contact type measuring device, an inner diameter measuring device, an outer diameter measuring device, a depth measuring device, a thickness measuring device, and a three-dimensional measurement. It can be applied to shape measuring instruments such as instruments. In addition, a compression spring is arranged between the inner tapered shaft and the outer tapered shaft to extend the axial distance between the inner tapered shaft and the outer tapered shaft, but the axial distance is extended by compression. The spring is not limited to a tension spring, and a fluid pressure such as hydraulic pressure or pneumatic pressure may be used. Further, the taper directions of the inner taper shaft and the outer taper shaft may be opposite to each other. Even in that case, it is necessary that the inner tapered shaft and the outer tapered shaft are quickly retracted when a collision event occurs and are normally pressed to extend the axial distance between them by a compression spring or the like.

Further, although grease is applied between the inner taper shaft and the outer taper shaft, the contact surfaces of both the inner taper shaft and the outer taper shaft can be surface-hardened to eliminate grease and the like. Since the retracting operation rarely occurs, surface treatment that does not cause galling between both tapered shafts may be performed.

10 ... Basic, 12 ... Main body, 14 ... Control device, 16 ... Spindle unit, 20 ... Z-axis drive means, 22 ... X-axis drive means, 24 ... Y-axis drive means, 26 ... Control unit (control unit), 28 ... Display unit, 30 ... XY table, 32 ... X-axis table, 34 ... Y-axis table, 36 ... work holding means, 40 ... work (measurement target), 42 ... measurement hole, 50 ... machine tool (dedicated machine), 70 ... Control unit for inner diameter measuring device, 78 ... Measuring unit, 79 ... Detection unit, 80 ... Bore gauge (measuring instrument), 81a, 81b ... Measuring element (contactor), 82a, 82b ... Measuring arm, 83a ... Support point, 84a ... Detection arm, 85a ... Displacement member, 86a ... Displacement detector, 87 ... Base, 88 ... Spring, 91 ... Displacement detector, 92 ... Protective member, 100 ... Inner diameter measuring device, 110 ... Sensor probe unit, 200 ... Collision retreat mechanism, 212 ... key (non-rotating), 214 ... key groove, 216 ... cylindrical part (sliding bearing), 218 ... tapered part (locking part), 220 ... cylindrical part (sliding bearing), 222 ... strut, 224 ... Lead wire, 226 ... Base, 228 ... Contact, 230 ... Inner taper shaft, 232 ... Spring holding hole, 234 ... Spring fitting hole, 236 ... Through hole, 240 ... Oil seal, 250 ... Outer taper shaft , 252 ... Oil seal holding hole, 254 ... Cylindrical part (sliding bearing), 256 ... Tapered part (locking part), 258 ... Cylindrical part (sliding bearing), 260 ... Keyway, 262 ... Compression spring, 264 ... Strut , 266 ... Contact, 268 ... Spring fitting hole, 270 ... Base plate, 272 ... Through hole, 280 ... Switch, 290, 292 ... Relief part, 302, 302a ... Tapered part gap, 304, 304a ... Bearing part gap (large) Diameter side), 306, 306a ... Bearing gap (small diameter side), st ... Retraction stroke

Claims (7)

In a measuring instrument that measures at least one of the inner diameter, outer diameter, depth, and thickness of an object to be measured.
The measuring instrument is a sensor probe unit having a measuring unit having a stylus and a detection unit arranged close to the measuring unit, and a portion extending in the axial direction of the sensor probe unit. Equipped with a collision evacuation mechanism attached to the sensor / probe section
The collision evacuation mechanism has an inner tapered shaft and an outer tapered shaft having a nested structure, and each of the inner tapered shaft and the outer tapered shaft has a tapered locking portion provided in an intermediate portion and the tapered locking portion. A measuring instrument having a large-diameter and small-diameter cylindrical portion provided on both axial end sides of the portion. The first aspect of claim 1, wherein the large-diameter and small-diameter cylindrical portions of the inner tapered shaft and the large-diameter and small-diameter cylindrical portions of the outer tapered shaft are opposed to each other and each of them is configured as a slide bearing. Measuring instrument. The outer tapered shaft is formed in an enlarged tubular shape, and a base plate is attached to the large diameter side of the expanded tubular, while the inner tapered shaft is also formed in an enlarged tubular shape, and the base plate and the inner tapered shaft are large. 1. The measuring instrument according to 2. A relief extending in the axial direction at the connection portion between the tapered locking portion of the inner tapered shaft and the cylindrical portion having the small diameter and the connecting portion between the tapered locking portion of the outer tapered shaft and the cylindrical portion having the large diameter. The measuring instrument according to any one of claims 1 to 3, wherein the portions are formed. A machine tool equipped with a switch having a contact connected to the sensor probe portion and a contact connected to the base plate, and a signal for stopping the axial movement of the measuring instrument by the operation of the switch is provided. The measuring instrument according to claim 3, which can be transmitted to the control unit of the instrument. Attached to the sensor probe of the measuring instrument, in the collision retracting mechanism the sensor probe portion retracts from the contact or contact or collision position by moving the sensor probe portion in the axial direction when colliding with the word click,
It has a nested inner taper axis and an outer taper axis,
Each of the inner tapered shaft and the outer tapered shaft has a tapered locking portion provided in the middle portion and a large-diameter and small-diameter cylindrical portion provided on both axial end sides of the tapered locking portion. Have and
Under normal conditions, the locking portion of the inner tapered shaft and the locking portion of the outer tapered shaft are substantially in close contact with each other and engaged, and the large-diameter and small-diameter cylindrical portions of the inner tapered shaft and the outer tapered shaft are engaged. A collision evacuation mechanism characterized in that the large-diameter and small-diameter cylindrical portions of the above face each other and form a slide bearing during the retracting operation. A tapered locking portion attached to the sensor probe portion of the measuring instrument and provided in the middle portion, and a large-diameter and small-diameter cylindrical portion provided on both axial end sides of the tapered locking portion. Collision using a collision evacuation mechanism equipped with a compression spring arranged so that an urging force acts in the axial direction with respect to the inner taper shaft and the outer taper shaft having a nested structure and the inner taper shaft and the outer taper shaft. In the evacuation method
Once the sensor probe portion contact or collide with the external object word click, the large-diameter and small-diameter cylindrical portion of said inner tapered shaft which face each other, the large-diameter and small-diameter cylindrical portion of the outer tapered shaft, but each A slide bearing is formed, and the inner tapered shaft is retracted axially toward the outer tapered shaft side.
When the sensor probe portion does not come into contact with or collide with an external object, the compression spring is extended to urge the inner tapered shaft so as to be axially separated from the outer tapered shaft, and the inner tapered shaft is subjected to. A collision evacuation method, characterized in that the tapered locking portion is substantially brought into close contact with the tapered locking portion of the outer tapered shaft.

Images