JP2019049425A - Measuring instrument, collision retreat mechanism used for the same, and collision retreat method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly evacuate a measuring instrument from a place where the event occurs without damaging the measuring instrument even if an abnormal event such as a collision with a measuring object or the like occurs, and to move the measuring instrument in the measurement after the evacuation. Accurately restores to the original position and enables highly accurate measurement. A measuring instrument 80 has a measuring unit having measuring elements 81a and 81b, a sensor probe unit 110 having a detection unit arranged close to the measuring unit, and an axial direction of the sensor probe unit 110. A collision evacuation mechanism 200, which is an extending portion and is attached to the sensor / probe portion 110, is provided. The collision evacuation mechanism 200 has an inner tapered shaft 230 and an outer tapered shaft 250 having a nested structure. Each of the inner tapered shaft 230 and the outer tapered shaft 250 has a large diameter provided on both axial end sides of the tapered locking portions 218 and 256 provided in the intermediate portion and the tapered locking portions 218 and 256. It has a cylindrical portion 216, 258 and a small diameter cylindrical portion 220, 254. [Selection diagram] Fig. 2

Description

  The present invention relates to a measuring instrument for measuring an inner diameter and the like, a collision evacuation mechanism used therefor, and a collision evacuation method, and in particular, a measuring instrument suitably used for automatic continuous measurement, a collision evacuation mechanism used therefor, and a collision evacuation method About.

  In a machine tool such as a machining center or the like, it is generally adopted to automate measurement of a processing part of a work after processing for the purpose of unmanned operation or labor saving. For example, the measuring instrument is automatically attached to the spindle unit to which the tool has been attached using an autochanger, and the measuring tool is automatically moved to the processing position according to a preprogrammed procedure. At that time, since unmanned measurement is the principle, it is necessary to also assume that the measuring instrument unintentionally touches or collides with the holding means for holding the work or the work for some reason. Patent Document 1 describes an example of protecting a measuring instrument by rapidly retracting (relying) 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 device capable of avoiding breakage of the measuring head at the time of a collision, the inner diameter measuring device is housed in a casing while being held by a holder. . The holder is pressed by a tension spring against a pedestal attached to the front end of the casing. When the measuring head receives a frontal collision, the holder retracts from the pedestal against the biasing force of the tension spring, thereby avoiding breakage of the measuring head due to the impact of the collision.

JP 2000-337806 A

  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 holder which is loosely fitted, 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 connection state of three circumferential contact points formed on the plane perpendicular to the axis of the holder.

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

  That is, since the entire holder moves against the spring force in the retraction operation of the measuring head, a force in the vertical direction acts on the axis of the measuring head due to a collision, and the entire holder is displaced in the axial direction as well as in the force acting direction. Do. After such displacement in the collision retraction operation, when the collision force is lost, a restoring force acts on the entire holder by the tension spring force. By the way, when a large acceleration is applied to the holder, the holder may be lifted obliquely due to the influence of the inertial force. In that case, it becomes difficult to hold the holder, and false detection may occur. This phenomenon becomes more pronounced as the holder length increases and the weight increases, and in the worst case, auto tool change can not be performed. In addition, when the contact changes its shape due to wear or the like, the contact condition of the contact naturally changes, making it impossible to achieve initial positioning.

  In order to eliminate this problem, it is also conceivable to support the axial movement of the measuring head by means of bearings. For example, when the measuring head is supported by a rolling bearing, the support of the measuring head should be used to withstand the impact of the measuring head on impact and not to cause vibration etc. of the measuring head at the time of contact with the hole at the time of measurement. It is necessary to increase the rigidity included, and the size of the rolling bearing increases. This causes the size of the measuring head itself to be increased and the cost of the measuring instrument to be increased. In addition, when the measuring head is supported by a slide bearing, a bearing gap is necessary in the slide bearing, and this gap is rattling, and this rattling causes a measurement error in normal measurement as well.

  The present invention has been made in view of the above-mentioned problems of the prior art, and the object of the present invention is to rapidly measure the measuring instrument without damaging it even if an abnormal event such as collision with the measuring object occurs. Evacuate the measuring instrument from the place where the event occurred, and at the same time, in the measurement after withdrawal, accurately restore the measuring instrument to its original position, and return with high accuracy without causing the inclination or eccentricity of the measuring instrument It is about making measurement possible.

  A feature of the present invention for achieving the above object is a measuring device 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 device comprises a measuring unit having a measuring element It has a sensor probe unit having a detection unit disposed close to the measurement unit, and a collision evacuation mechanism attached to the sensor probe unit as a portion extending in the axial direction of the sensor probe unit. The collision / retraction mechanism has a nested structure inner tapered shaft and an outer tapered shaft, and each of the inner tapered shaft and the outer tapered shaft has a tapered locking portion provided at an intermediate portion and the tapered locking. It has a large diameter and a small diameter cylindrical portion provided on both axial direction end sides of the portion.

  And 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 are made to face each other and configured as slide bearings, respectively; The tapered shaft is formed in an enlarged tubular shape, and the base plate is attached to the large diameter side of the enlarged tubular, while the inner tapered shaft is also formed in the enlarged tubular shape, and the large diameter side of the base plate and the inner tapered shaft Preferably, a compression spring is provided between the sensor and the probe, and the compression spring biases the sensor / probe portion axially away from the collision / retraction mechanism during normal use.

  Further, in the above-mentioned feature, the relief portion extending in the axial direction to the connecting portion between the tapered locking portion of the inner tapered shaft and the small diameter cylindrical portion and the connecting portion between the tapered locking portion of the outer tapered shaft and the large diameter cylindrical portion And a switch having a contact point connected to the sensor / probe portion and a contact point connected to the base plate, and a signal for stopping an axial movement of the measuring means by the operation of the switch. It may be possible to transmit to a control unit such as a machine tool or the like to which is attached.

  Another feature of the present invention for achieving the above object is that it is attached to a sensor probe portion of a measuring instrument, and moves the sensor probe portion in its axial direction when the sensor probe portion contacts or collides with a work or the like. Collision retracting mechanism for retracting from the contact or collision position, having a nested inner tapered shaft and an outer tapered shaft, each of the inner tapered shaft and the outer tapered shaft being a tapered locking portion provided at an intermediate portion And a large diameter and a small diameter cylindrical portion provided on both axial ends of the tapered locking portion, the locking portion of the inner tapered shaft and the locking portion of the outer tapered shaft in a normal state The large-diameter, small-diameter cylindrical portion of the inner tapered shaft and the large-diameter, small-diameter cylindrical portion of the outer tapered shaft of the inner tapered shaft face each other, and the sliding bearing is It is about forming.

  Yet another feature of the present invention for achieving the above object is a tapered locking portion provided at the middle portion and attached to the sensor probe portion of the measuring instrument, and both axial ends of the tapered locking portion. Collision retracting mechanism comprising a nested inner and outer tapered shaft having a large diameter and a small diameter cylindrical portion provided on the side, and a compression spring disposed between the inner tapered shaft and the outer tapered shaft In the method of use, when the sensor probe portion contacts or collides with an external object such as a workpiece, the large and small diameter cylindrical portions of the inner tapered shaft and the large and small diameter cylindrical portions of the outer tapered shaft face each other. Forms 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 extends and the inner The tapered shaft is biased axially away from the outer tapered shaft, and the tapered locking portion of the inner tapered shaft is brought into substantially close contact with the tapered locking portion of the outer tapered shaft. It is in.

  According to the present invention, since the shaft having the slide bearing portion at both ends of the tapered shaft is provided in the measuring instrument, even if an abnormal event such as the measuring instrument collides with the measuring object occurs, the measuring instrument is not damaged. It can be quickly evacuated from the place where the event occurred. Further, in return measurement after retraction, the measuring head is moved in the axial direction with the tapered shaft as a guide, so that high-precision measurement can be performed without causing inclination or eccentricity of the measuring instrument.

It is a front view of one example of a measuring device which attached a measuring instrument concerning the present invention. It is an exploded view of one example of a collision evacuation mechanism of a measuring instrument concerning the present invention. It is a fragmentary sectional view of a measuring instrument explaining operation of a collision retreat mechanism shown in FIG. It is a figure explaining the operation | movement of the collision evacuation mechanism shown in FIG. It is sectional drawing which shows an example of the measuring head of a measuring device.

  Hereinafter, embodiments of a measuring device according to the present invention and a collision evacuation mechanism used therefor will be described using the drawings. FIG. 1 is a front view of an embodiment of a machine tool 50 incorporating a measuring device 80 according to the present invention, the measuring device 80 being an inside diameter measuring device (bore gauge). In this embodiment, the inner diameter measuring device is taken as an example of the measuring device 80, but the measuring device 80 is not limited to the inner diameter measuring device, and an outer diameter measuring device, a thickness measuring device, a depth measuring device, a contact type The present invention can be applied to various devices such as three-dimensional measuring devices, non-contact measuring devices such as laser heads and cameras, and observation devices.

  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 device) 80 which is an inner diameter measuring device according to the present invention is attached to the shank. The bore gauge 80 is vertically movable with the spindle portion 16 by Z-axis drive means 20 including a motor attached to the upper portion of the main body 12. A workpiece 40 to be measured is disposed below the bore gauge 80 and fixedly held on the XY table 30 by the workpiece holding means 36.

  In this embodiment, the X-axis table 32 on the upper side of the X-Y table 30 includes the motor by the X-axis drive means 22 and the Y-axis table 34 on the lower side includes the motor by the Y-axis drive means 24 respectively. It is linearly driven in the direction (left and right direction in this figure) and in the Y direction (vertical direction in the figure). Therefore, the relative position of the bore gauge 80 and the work 40 is positioned by driving the spindle unit 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. Be done. Or, although not shown in the drawings, it further comprises a weir table to enable rotational movement.

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

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

Next, details of the bore gauge 80 as an inner diameter measuring device according to the present invention will be described in detail using FIGS. 2 to 4. Fig.2 (a) is an exploded view of one Example of the bore gauge 80 which concerns on this invention, FIG.2 (b) is an A view in FIG. 2 (a). FIG. 3 is a partial vertical cross-sectional view showing a state of the bore gauge 80 shown in FIG. 2 in the operating state, and FIG. 3 (a) is a view corresponding to measurement, and FIG. 3 (b) is in the retracted state. FIG. Figure 3 (c), (d) is an enlarged view showing the _D 1, _{D 2} parts of details, respectively, of FIG 3 (a). FIG. 4 is a diagram for explaining the transition between the measurement-ready state and the retracted state of the bore gauge 80, and FIG. 4 (a) is a view showing the retracted state substantially coaxially, and FIG. 4 (b) is bent, ie coaxial FIG. 4C is a view showing a state of recovery to the measurement corresponding state.

Returning to FIG. 2, in the bore gauge 80, a collision evacuation mechanism 200 is provided on the side of the sensor / probe unit 110 having the measuring element connected to the spindle unit which is the counter measurement side. In the collision evacuation mechanism 200, the inner tapered shaft 230 is fixed to the sensor probe portion 110 using a 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 conically spreads from the sensor probe portion 110 side to the open end portion in the axially middle portion, and both axial end portions of the tapered portion 218 A small diameter cylindrical portion 220 and a large diameter cylindrical portion 216 are formed in the. A key groove 214 is formed at one open end side of the inner tapered shaft 230 and in one circumferential direction. The keyway 214, the key 212 is fitted from the radially outer side as shown by an arrow B _1.

  A plurality of stepped holes are formed in the interior of the inner tapered shaft 230, and the smallest diameter holes pass through the axially extending columns 222 supporting the pedestal 226 holding the contacts 228 of the switch 280. Through holes 236 for making the One end of a lead wire 224 is connected to the switch 280 and is used to transmit a switch 280 signal to a control unit (control unit) 26 provided in a machine tool 50 such as a machining center to which the measuring instrument 80 is attached.

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

  The outer cylindrical 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 diameter cylindrical inner surface on the small diameter end side. The cylindrical portion 254 is formed of a cylindrical portion 258 having an inner diameter and a large diameter cylindrical inner surface on the large diameter end side. A key groove 260 corresponding to the key groove 214 of the inner tapered shaft 230 is formed in one circumferential direction of the large diameter cylindrical inner surface, and enables the key 212 to be smoothly fitted. The key 212 acts as a detent to prevent circumferential displacement of the outer tapered shaft 250 relative to the inner tapered shaft 230.

An oil seal holding hole 252 for holding the oil seal or lip seal 240 is formed on the minimum inner diameter side of the outer tapered 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 disc-like base plate 270 closing the axial 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 is electrically connected to the contact point 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 234 prevent the springs 262 from falling off when the inner tapered shaft 230 is axially displaced with respect to the outer tapered shaft 250, and the biasing force of the spring 262 Work along the central axes of the outer tapered shaft 250 and the inner tapered shaft 230.

  The collision evacuation operation of the measuring device 80 configured as described above will be described with reference to FIGS. 3 and 4. FIG. 3A is a diagram showing a state in which the measuring device 80 is brought close to the workpiece 40 to be measured in order to start measurement in a state where the measuring device 80 is attached to a machine tool or the like (not shown). A compression spring 262 is attached between the outer tapered shaft 250 and the inner tapered shaft 230, and the biasing force of the compression spring 262 acts in the axial direction to attach the inner tapered shaft 230 attached to the sensor probe portion 110. Of the tapered portion 218 is urged to press the tapered portion 256 of the outer tapered shaft 250. As a result, a retraction stroke st is formed between the spring attachment 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 in close contact with each other at the respective tapered portions 218 and 256. In the present embodiment, stainless steel SUS304 is used for the inner tapered shaft 230 and the outer tapered shaft 250. Since the inner tapered shaft 230 and the outer tapered shaft 250 are the same material, there is a risk that galling or friction may occur due to the sliding. 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 in order to prevent such problems. Therefore, the substantially intimate contact between the tapered portions 218 and 256 also includes contact via a grease film. In addition, since grease is applied to each of the inner tapered shaft 230 and the outer tapered shaft 250, the oil seal or lip seal 240 is attached to one end face of the outer tapered shaft 250 to prevent the grease from flowing out. 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 measuring elements 81a and 81b are extended outward in the direction perpendicular to the axis of the sensor probe portion 110 to make the inner diameter taking measurement. At that time, in the collision retraction mechanism 200, the tapered portions 218 and 256 of the inner tapered shaft 230 and the outer tapered shaft 250 are in contact, and the end surface of the inner tapered shaft 230 and the end surface of the base plate 270 attached to the outer tapered shaft 250 As described above, the retraction 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 The probe elements 81a and 81b of 110 are protected from collision because they do not exceed the outer diameter of the sensor probe portion 110, but the sensor probe portion 110 may be damaged. Therefore, the sensor / probe unit 110 is quickly retracted from the workpiece 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 biasing force of the compression spring 262 interposed between the inner tapered shaft 230 and the outer tapered shaft 250 3 to the left in FIG. 3 and is displaced up to a position before the retraction stroke st.
As described above, the position before the retraction stroke st is allowing for a safety margin until the machine tool stops. When the retraction stroke st is retracted, the impact of the collision is the bore gauge and the workpiece immediately after that. It is because it may be transmitted to the main shaft of the machine and cause damage to the bore gauge.
For example, if the retraction stroke st is 5 mm, it is preferable that the contacts 228 and 266 of the switch 280 contact and detect a collision when the stroke is about 0.3 mm. In this way, the remaining stroke can be a safety margin from the detection of a collision to the actual stop. Therefore, even if the switch 280 slightly moves from the detection of the contact to the actual stop, it can be stopped at a position before the retraction stroke st. At this time, a gap is formed between the inner diameter side of the outer tapered shaft 250 and the outer diameter side of the inner tapered shaft 230.

  As the inner tapered shaft 230 moves so as to close the axial distance with respect to the outer tapered shaft 250, the contacts 228 and 266 of the switches 280 provided respectively come into contact and electrically detect a collision. The detected collision is transmitted to the control unit 26 provided to the machine tool 50 through the lead wire 224, and the machine tool 50 immediately stops the movement of the entire measuring unit 80, that is, the spindle unit to the workpiece 40. As a result, before the end surface 242 of the inner tapered shaft 230 contacts the end surface 244 of the base plate 270 of the outer tapered shaft 250, that is, before moving the entire stroke of the retraction stroke st, the inner tapered shaft 230 ends the collision retraction operation. Do.

  Details of the 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 activated. In order to facilitate understanding, the gaps and the like are illustrated exaggeratingly. As described above, the inner tapered shaft 230 is not necessarily displaced by the maximum stroke st, and the displacement is often stopped halfway by the operation of the switch 280. In the collision retraction operation, the inner tapered shaft 230 and the outer tapered shaft 250 release the contact or the locking at the respective tapered portions (locking portions) 218 and 256, and the large and small diameter cylindrical portions 216 and 220, respectively. Forming a sliding bearing with gaps 304, 306 between 258, 254;

  That is, in the collision retraction operation, the slip lubricated by the grease having a gap 306 between the inner peripheral surface of the small diameter cylindrical portion 254 of the outer tapered shaft 250 opposed to the outer peripheral surface of the small diameter cylindrical portion 220 of the inner tapered shaft 230 A bearing and a slide bearing lubricated with grease 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 opposed to each other; , Each form. As a result, when an unexpected event of collision of the measuring device 80 occurs, the inner tapered shaft 230 quickly retracts with the slide bearing as a guide in the direction opposite to the moving direction of the measuring device 80. Since a slide bearing is provided, there is almost no resistance associated with retraction, and it is only required that only a force against the spring 262 be generated by a 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 released from the gaps 304 and 306 of the bearing due to the displacement of the inner tapered shaft 230. Because it becomes large, it does not become resistance when the inner tapered shaft 230 is displaced.

  Since each cylindrical portion 216, 220; 254, 258 of the inner tapered shaft 230 and the outer tapered shaft 250 may act as a bearing, the gaps 304, 306 between them make a proper gap as a sliding bearing. In the normal sliding bearing, a gap of several percent or less of the diameter of the shaft to be supported is formed, so that the gaps 304 and 306 are as small as possible within the above range in this embodiment as well. In order to quickly retract the inner tapered shaft 230, that is, the sensor probe portion 110, the clearances 304, 306 are necessary, but when the measurement state is entered with the clearance held, the clearances 304, 306 become the measuring device 80. Lower the rigidity of the sensor and make it more prone to measurement errors. Therefore, as described above, at the time of measurement, the tapered portions 218 and 256 are substantially in direct contact with each other, thereby eliminating the 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 view showing the transition from the large-diameter cylindrical portions 216 and 258 of the inner tapered shaft 230 and the outer tapered shaft 250 to the tapered portions 218 and 256, respectively. A concave surface is formed at the boundary between the cylindrical portion 258 and the tapered portion 256. Generally, when the concave surface is formed by turning etc., the influence of the blade tip R (the mark of the tip radius R of the blade remains for processing of the angled portion due to the radius R of the blade tip) remains at the boundary after machining . 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 axially extended to the tapered portion 256 side, and the relief portion 290 is formed at the connection portion between the cylindrical portion 258 and the tapered portion 256. This avoids interference between the inner tapered shaft 230 and the outer tapered shaft 250.

  Even at the transition from the tapered portion 218 of the inner tapered shaft 230 to the small diameter cylindrical portion 220, the outer surface is recessed, that is, a corner with a cross-sectional shape of less than 180 ° is formed, thereby preventing interference by the cutter R by turning. Therefore, the cylindrical portion 220 is axially extended at this portion, and the relief portion 292 is formed at the connection portion between the cylindrical portion 220 and the tapered portion 218. Thereby, the interference of the inner tapered shaft 230 and the outer tapered shaft 250 is avoided.

  4 (a) and 4 (b) show the operation of the collision retraction mechanism 200, and FIG. 4 (a) shows the longitudinal axis of the measuring device 80 by using the above-mentioned bearing. When it is evacuated along almost On the other hand, since the relative movement of the inner tapered shaft 230 is an instantaneous operation, it is assumed that the inner tapered shaft 230 retreats by tilting or eccentrically within the range of the bearing gap due to the collision state of the measuring device 80 and the work 40 Be done. FIG. 4 (b) shows an example in which such misalignment and retraction are performed. The central axis of the inner tapered shaft 230 is no longer coincident 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. At the time of retraction, although the inner tapered shaft 230 is inclined within the range of the bearing gap, when the compression spring 262 is extended, the tapered portion 218 of the inner tapered shaft 230 and the tapered portion 256 of the outer tapered shaft 250 become guides and the inclination of the inner tapered shaft 230 The tapered portions (locking portions) 218 and 256 come into substantially close contact with each other with the axial center of the outer tapered shaft 250 being aligned with the axial center of the outer tapered shaft 250 after correction. As a result, it is possible to prevent the occurrence of measurement error at the time of measurement caused by bending or deviation of the axial center of the measuring device 80.

  An example of the sensor probe portion 110 of the bore gauge (measuring device) 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 is a view with the upper portion omitted. The sensor / probe unit 110 is for measuring the inner diameter. In FIG. 5, only the left part is shown in a cross-sectional view, but the same applies to the right part, so the description of the right part will be omitted. Therefore, for the right part, the suffix a of each part in the description of the left part may be replaced with b.

  The sensor / probe unit 110 has an outer diameter corresponding to the inner diameter of the measurement hole (or hollow portion) 42 of the work 40, and below the below-described measurer 81a, 81b is provided movably in the radial direction It has a measuring section 78 which is extended to the lower side of the cylindrical shape. Above the measurement unit 78, an inner diameter detection unit 79 is provided that converts the amount of movement of the tracing styluses 81a and 81b into an electrical signal.

  That is, the measuring arm 82 a extends long downward along the axis of the sensor / probe unit 110, and is rotatably supported by the fulcrum 83 a disposed in the detection unit 79. A probe (contactor) 81a which is cylindrical and has a hemispherical tip is provided in the vicinity of one end of the measurement arm 82a, and the axis of the probe 81a is the measurement arm 82a. It is attached at right angles to the direction of extension of. However, as long as the displacement in the direction orthogonal to the central axis of the sensor / probe unit 110 can be measured, it may be attached obliquely. The other end of the measurement arm 82a is a detection arm 84a, and the detection arm 84a extends in a direction substantially perpendicular to the axial direction of the measurement arm 82a in order to expand the displacement of the probe 81a. There is.

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

  The outer peripheral sides of the measurement unit 78 and the detection unit 79 are protected by a bottomed protection member 92. The bottom of the protective member 92 is larger in diameter than the outer diameter of the position at which the probes 81a and 81b are disposed. When the sensor / probe unit 110 is positioned in the workpiece 40, the probes 81 a and 81 b are retracted inside the sensor / probe unit 110. As a result, it is possible to prevent contact with an object outside the sensor probe unit 110 which is not intended due to the measurement elements 81a and 81b being positioned to the outer diameter side beyond the bottom diameter and the like.

  In the above embodiment, the lever-type internal diameter measuring device has been described as an example, but the internal diameter measuring device is not limited to this, and various types can be used. Furthermore, the measuring device is not limited to the inner diameter measuring device, and an inner diameter measuring device, an outer diameter measuring device, a depth measuring device, a thickness measuring device, and a three-dimensional measurement which are arranged in the vicinity of a work in contact or non-contact type. It can be applied to shape measuring instruments such as In addition, a compression spring is disposed between the inner tapered shaft and the outer tapered shaft so as to extend the axial distance between the inner tapered shaft and the outer tapered shaft, but it is necessary to extend the axial distance by compression. Not only the spring but also a fluid pressure such as a tension spring, oil pressure or air pressure may be used. Furthermore, the tapers of the inner and outer tapered shafts may be in opposite directions. Even in this case, the inner tapered shaft and the outer tapered shaft need to be quickly retracted by a compression spring or the like in the event of a collision event, and normally be extended to extend the axial distance between each other.

  Although grease is applied between the inner tapered shaft and the outer tapered shaft, the contact surfaces of both the inner tapered shaft and the outer tapered shaft can be surface-hardened to eliminate grease and the like. Since the occurrence of the retracting operation is rare, it is sufficient to perform a surface treatment that does not cause galling between both taper shafts.

  DESCRIPTION OF SYMBOLS 10 ... Foundation, 12 ... Main body, 14 ... Control device, 16 ... Spindle part, 20 ... Z-axis drive means, 22 ... X-axis drive means, 24 ... Y-axis drive means, 26 ... Control part (control part), 28 ... Display unit, 30: XY table, 32: X axis table, 34: Y axis table, 36: work holding means, 40: work (measurement object), 42: measurement hole, 50: machine tool (special machine), 70 Control unit for inner diameter measuring device 78 Measurement unit 79 Detection unit 80 Bore gauge (measuring device) 81a, 81b Measuring element (contactor) 82a, 82b Measuring arm 83a fulcrum 84a ... detection arm, 85a ... displacement member, 86a ... displacement detector, 87 ... base, 88 ... spring, 91 ... displacement detector, 92 ... protection member, 100 ... inside diameter measuring device, 110 ... sensor probe unit, 200 ... ... Collision evacuation mechanism, 21 ... Key (rotational stop), 214 ... Key groove, 216 ... Cylindrical part (slide bearing), 218 ... Tapered part (locking part), 220 ... Cylindrical part (slide bearing), 222 ... Post, 224 ... Lead wire, 226 ... stand portion, 228 ... contact point, 230 ... inner tapered shaft, 232 ... spring holding hole, 234 ... spring fitting hole, 236 ... through hole, 240 ... oil seal, 250 ... outer tapered shaft, 252 ... oil seal Holding hole portion 254: cylindrical portion (slide bearing) 256: tapered portion (locking portion) 258: cylindrical portion (slide bearing) 260: key groove 262: compression spring 264: support column 266: contact point 268: spring fitting hole, 270: base plate, 272: through hole, 280: switch, 290, 292: relief portion, 302, 302a: taper portion gap, 304, 304a: bearing portion gap (large diameter side), 306 , 30 a ... bearing portion gap (small diameter side), st ... retracting stroke

Claims (7)

In a measuring instrument that measures at least one of an inner diameter, an outer diameter, a depth and a thickness of an object to be measured,
The measuring instrument is a sensor / probe section having a measuring section having a measuring element and a detecting section disposed close to the measuring section, and an axially extending section of the sensor / probe section. It has a collision evacuation mechanism attached to the sensor probe section,
The collision / retraction mechanism has a nested inner tapered shaft and an outer tapered shaft, and each of the inner tapered shaft and the outer tapered shaft has a tapered locking portion provided at an intermediate portion and the tapered locking. A measuring instrument characterized by having a large diameter and a small diameter cylindrical portion provided on both axial direction end sides of the portion.   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 made to face each other, and they are respectively configured as slide bearings. 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 enlarged tubular, while the inner tapered shaft is also formed in an enlarged tubular shape, and the large diameter of the base plate and the inner tapered shaft A compression spring is disposed between the radial side and the compression spring, and the compression spring biases the sensor / probe unit axially away from the collision / retraction mechanism during normal use. The measuring device as described in 2.   Recesses extending in the axial direction respectively at the connecting portion between the tapered locking portion of the inner tapered shaft and the small diameter cylindrical portion and at the connecting portion between the tapered locking portion of the outer tapered shaft and the large diameter cylindrical portion The measuring instrument according to any one of claims 1 to 3, characterized in that a part is formed.   A machine tool is provided with a switch having a contact point connected to the sensor / probe unit and a contact point connected to the base plate, and a signal for stopping axial movement of the measuring machine by the operation of the switch is a machine tool to which the measuring machine is attached The measuring instrument according to claim 3, which can transmit data to the control unit. A collision / evacuation mechanism attached to a sensor / probe unit of a measuring instrument, and when the sensor / probe unit contacts or collides with a workpiece or the like, moves the sensor / probe unit in its axial direction and withdraws from the contact or collision position.
With nested inner and outer tapered shafts,
Each of the inner tapered shaft and the outer tapered shaft has a tapered locking portion provided at the middle portion and a large diameter and a small diameter cylindrical portion provided on both axial direction end sides of the tapered locking portion. Have
The locking portion of the inner taper shaft and the locking portion of the outer taper shaft are substantially in close contact and locked in a normal state, and the large diameter, small diameter cylindrical portion of the inner taper shaft and the outer taper shaft What is claimed is: 1. A collision retracting mechanism characterized in that the large diameter, small diameter cylindrical portions of each face each other, and form a sliding bearing during retraction operation. It is attached to the sensor probe section of the measuring instrument, and has a tapered locking section provided in the middle section, and a large diameter and a small diameter cylindrical section provided on both axial end sides of the tapered locking section. A collision retracting method using a collision retracting mechanism comprising a nested tapered inner and outer tapered shafts, and a compression spring disposed between the inner and outer tapered shafts;
When the sensor / probe unit contacts or collides with an external object such as a workpiece, the large and small diameter cylindrical portions of the inner tapered shaft and the large and small diameter cylindrical portions of the outer tapered shaft slide against each other. Forming a bearing to axially retract the inner tapered shaft toward the outer tapered shaft;
When the sensor probe does not contact or collide with an external object, the compression spring extends and biases the inner tapered shaft axially away from the outer tapered shaft to taper the inner tapered shaft 4. A collision retracting method characterized in that a hook-shaped locking portion is substantially in close contact with the tapered locking portion of the outer tapered shaft.