JP2007033084A - Measurement instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measurement instrument capable of simply changing a spindle. <P>SOLUTION: The measurement instrument comprises a spindle 300 movable axially and a phase signal transmission means 400 for transmitting different signal to different rotation angle of the spindle 300 corresponding to the rotation of the spindle 300. The spindle 300 is provided with an engaging groove 320 in the axial direction. The phase signal transmission means comprises the rotor rotating integrally with the spindle 300, the stator for transmitting the phase signal corresponding to the rotational angle of the rotor provided with the state opposite to the rotor, an engaging pin 421 for engaging with an engaging groove 320 provided with a rotor bush 423, and an engaging pin support means 450 for retaining an engaging pin 421 to the rotor. The engage pin supporting means 450 is constituted by engaging an engaging pin 421 to a leaf spring 441. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a measuring instrument. For example, the present invention relates to a measuring instrument that measures the dimension of an object to be measured by moving a spindle back and forth, such as a measuring instrument represented by a micrometer, a micrometer head, or the like.

2. Description of the Related Art Conventionally, measuring instruments such as a micrometer or a micrometer head that measure the dimensions of an object to be measured by moving a spindle back and forth by screwing rotation are known (for example, Patent Document 1 and Patent Document 2).
The measuring instrument includes a main body having an internal thread, a spindle having a feed screw screwed into the internal thread of the main body, a rotation detecting means for detecting the rotation of the spindle, and a displacement of the spindle based on a signal output from the rotation detecting means. Arithmetic processing means for obtaining the quantity.

The rotation detecting means includes a rotor that rotates integrally with the spindle, and a stator that is provided in a state of facing the rotor and detects the rotation of the rotor.
An engagement groove is formed on the spindle, and an engagement pin that engages with the engagement groove is provided on the rotor.

In such a configuration, when the spindle rotates, the spindle advances and retreats in the axial direction by screwing rotation of the main body and the spindle. The rotation of the spindle at this time is detected by the rotation detecting means. That is, when the spindle rotates, the rotor rotates integrally with the spindle due to the engagement between the engaging groove of the spindle and the engaging pin of the rotor, and the rotation of the rotor is detected by the stator.
Then, the amount of displacement of the spindle is obtained based on the detected rotational phase of the rotor and the advance / retreat pitch of the spindle.
Japanese Utility Model Publication No. 49-80260 JP-A-54-130152

However, when replacing the spindle, there is a problem that when the spindle is removed from the rotor, the engaging pin falls out of the rotor. Then, the engaging pin becomes an obstacle to set the spindle on the rotor again, or the engaging pin needs to be reinserted into the rotor to be engaged with the engaging portion of the spindle.
For this reason, when the spindle was replaced, all the measuring instruments had to be disassembled and reassembled, which was very troublesome.

  The objective of this invention is providing the measuring device which can replace | exchange a spindle simply.

  The measuring instrument of the present invention includes a main body, a spindle screwed into the main body and provided so as to be able to advance and retract in the axial direction by rotation, and different values for different rotation angles of the spindle according to the rotation of the spindle. Phase signal transmitting means for transmitting a phase signal, and arithmetic processing means for calculating the phase signal to obtain an absolute position of the spindle, wherein the spindle has an engaging portion provided along the axial direction. The phase signal transmitting means includes a rotor that rotates integrally with the spindle, a stator that is provided in the main body in a state of being opposed to the rotor, and that transmits a phase signal corresponding to a rotation angle of the rotor, and the rotor And an engagement pin supporting means for retaining the engagement pin with respect to the rotor.

  In such a configuration, when the spindle is rotated, the spindle advances and retreats with respect to the main body by screwing of the spindle and the main body. At this time, a phase signal corresponding to the rotation angle of the spindle is transmitted from the phase signal transmitting means according to the rotation of the spindle. The rotational phase of the spindle is obtained from this phase signal, and the amount of displacement of the spindle is obtained from the rotational phase and the advance / retreat pitch of the spindle.

  According to such a configuration, the engaging pin is prevented from coming off from the rotor by the engaging pin support means. Then, even when the spindle is removed from the rotor, the position of the engaging pin is maintained, so that it is easy to set the spindle with respect to the rotor again. For example, if the engagement pin falls out of the rotor when the spindle is removed from the rotor, the engagement pin may get in the way to set the spindle back on the rotor, or the engagement pin may be reinserted into the rotor. Since it has to be engaged with the engaging part of the spindle, it is very laborious.

  In this regard, in the present invention, the engagement pin is prevented from coming off from the rotor by the engagement pin support means, so that the position of the engagement pin is maintained as it is even if the spindle is removed from the rotor, and the spindle is set in the rotor. Easy to do. Therefore, the spindle can be exchanged easily.

  In this invention, it is preferable that the said phase signal transmission means is provided with the pre-load provision means which pre-presses the said engaging pin toward the said engaging part.

  In such a configuration, when the spindle is rotated, the rotation of the spindle is transmitted to the rotor by the engagement between the engaging portion of the spindle and the engaging pin of the rotor. Then, the rotor is rotated by the same rotation angle as the spindle, and the rotation angle of the rotor is read by the stator. Therefore, the rotation angle of the spindle can be known, and the displacement amount of the spindle can be known from the pitch per rotation of the spindle.

According to such a configuration, since the engagement pin is preloaded toward the engagement portion by the preload applying means, the engagement pin and the engagement portion are reliably engaged without a gap, and the rotation of the spindle is performed by the rotor. Accurately communicated to. Therefore, the rotation angle of the spindle can be accurately detected by reading the rotation angle of the rotor with the stator. For example, when the amount of advancement / retraction per rotation of the spindle is large, the detection resolution of the spindle position cannot be increased unless the rotation angle of the spindle is detected with a high resolution, and a slight gap between the engagement pin and the engagement portion. However, the effect on the measurement is large.
In this regard, according to the present invention, since the engagement pin and the engagement portion are engaged with each other by the preload applying means without any gap, the rotation of the spindle can be accurately transmitted to the rotor. As a result, measurement accuracy can be improved.

  In the present invention, the engagement pin is slidably provided in a direction perpendicular to the axial direction of the spindle with respect to the rotor, and the preload applying means is hooked on the rotor and the engagement is performed. It is preferable that the pin is constituted by a leaf spring that urges the pin toward the engaging portion.

  According to such a configuration, since the engagement pin is preloaded toward the engagement portion by the elasticity of the leaf spring, the engagement pin and the engagement portion are secured while ensuring the sliding between the engagement pin and the engagement portion. Are engaged without gaps. Therefore, the rotation of the spindle is accurately transmitted to the rotor. As a result, the reading error of the spindle rotation angle is reduced, and the measurement accuracy can be improved.

  Note that the engagement pin may be pre-pressurized toward the engagement portion by screwing the engagement pin into the rotor and screwing the engagement pin until the tip of the engagement pin strongly contacts the engagement portion of the spindle. .

  In the present invention, it is preferable that the engagement pin support means is configured by engaging an engagement pin with the leaf spring.

Thus, by engaging the engagement pin with the leaf spring, even when the spindle is pulled out, the engagement pin does not fall out of the rotor, and the position of the engagement pin is substantially maintained.
As a result, it is easy to set the spindle on the rotor, and the spindle can be easily replaced.

  Note that the position of the engagement pin may be substantially fixed by screwing the engagement pin to the rotor or the rotor bush.

  In the present invention, the spindle is preferably displaced by 1 mm or more per rotation.

  Specifically, it is preferable that the main body has a female screw, the spindle has a feed screw screwed into the female screw of the main body, and the screw pitch of the female screw and the feed screw is 1 mm or more. Alternatively, the feed screw is preferably a multi-thread screw.

  In such a configuration, when the spindle is rotated, the spindle advances and retreats by 1 mm or more per rotation, so that the advance / retreat speed of the spindle is increased and the operability of the measuring instrument is improved.

  In the present invention, the main body includes a spindle operation unit that manually operates rotation of the spindle, and the spindle operation unit includes a cap cylinder that is rotatably provided on an outer surface of the main body, and the cap cylinder. When the load that is provided between the spindle and acts between the cap cylinder and the spindle is less than a predetermined value, the rotation of the cap cylinder is transmitted to the spindle, and the load is not less than the predetermined value. In some cases, it is preferable to include a constant pressure mechanism that idles between the cap cylinder and the spindle.

In such a configuration, when the cap cylinder is rotated, the rotation of the cap cylinder is transmitted to the spindle through the constant pressure mechanism below the predetermined load, and the spindle is rotated. Then, the spindle advances and retreats. Further, when the cap cylinder is rotated when the load is equal to or greater than the predetermined load, the constant pressure mechanism idles and rotation of the cap cylinder is not transmitted to the spindle. For example, since the spindle is not rotated with a force greater than or equal to a predetermined load due to idling of the constant pressure mechanism, the contact pressure when the spindle contacts the object to be measured can be regulated to a predetermined pressure or less. Therefore, the object to be measured is not damaged by the spindle.
In particular, if the advance / retreat pitch per rotation of the spindle is increased, the spindle may be displaced at a high speed, which may damage the object to be measured. In this respect, in the present invention, the spindle is more than a predetermined load by the constant pressure mechanism. The object to be measured is not damaged by the spindle.

  The measuring instrument of the present invention includes a main body, a spindle screwed into the main body and provided so as to be able to advance and retract in the axial direction by rotation, and different values for different rotation angles of the spindle according to the rotation of the spindle. A phase signal transmitting means for transmitting a phase signal; and an arithmetic processing means for calculating the absolute position of the spindle by calculating the phase signal, and the phase signal transmitting means transmits the phase signal at a predetermined pitch. The calculation processing means calculates a rotation angle of the spindle based on the phase signal, and rotates the spindle based on the rotation angle of the spindle calculated by the rotation angle calculation unit. A rotation number calculation unit that counts the number, a rotation number of the spindle counted by the rotation number calculation unit, and a rotation angle of the spindle calculated by the rotation angle calculation unit A total rotation phase calculation unit that calculates a total rotation phase of the spindle based on the spindle, and a spindle position calculation unit that calculates the absolute position of the spindle based on the total rotation phase of the spindle calculated by the total rotation phase calculation unit And preferably.

  In such a configuration, when the spindle is rotated, the spindle advances and retreats with respect to the main body by screwing of the spindle and the main body. At this time, a phase signal corresponding to the rotation angle of the spindle is transmitted from the phase signal transmitting means according to the rotation of the spindle. This phase signal has different values for different rotation angles of the spindle. The rotation angle θ is in a range of 0 ° ≦ θ <360 °, that is, a phase within one rotation. Based on this phase signal, the rotation angle of the spindle is uniquely determined by the rotation angle calculation unit. Further, since the rotation angle of the spindle is sequentially calculated by the rotation angle calculation unit, the rotation number of the spindle is calculated by the rotation number calculation unit based on the calculated rotation angle of the spindle. For example, when the rotation angle of the spindle calculated by the rotation angle calculation unit changes from 5 ° → 95 ° → 185 ° → 275 ° → 365 °, the spindle is rotated once. The number of rotations is incremented by +1.

  The total rotation phase of the spindle is calculated by the total rotation phase calculation unit based on the rotation number of the spindle counted by the rotation number calculation unit and the rotation angle of the spindle calculated by the rotation angle calculation unit. For example, if the rotation speed of the spindle is 2 and the rotation angle is 45 °, the total rotation phase is 765 ° (= 360 ° × 2 + 45 °). The absolute position of the spindle is calculated by the spindle position calculation unit based on the total rotation phase calculated by the total rotation phase calculation unit. For example, when the advance / retreat pitch per rotation of the spindle is 2 mm and the total rotation phase is 765 °, the absolute position of the spindle is 4.25 mm (= 765 ° ÷ 360 ° × 2 mm).

  According to such a configuration, when the rotation angle of the spindle is obtained based on the phase signal from the phase signal transmitting means, the phase signal has a different value for different rotation angles of the spindle. The rotation angle is uniquely determined. Conventionally, the rotation phase of the spindle is detected by incrementing the pulse signal according to the rotation of the spindle. Therefore, if the change of the pulse signal with respect to the rotation of the spindle is too early, the signal is frequently skipped and the spindle is accurately detected. The rotation phase could not be detected. For this reason, the rotation speed of the spindle is limited or the number of signal changes per rotation of the spindle is reduced so that the increment is performed accurately. However, limiting the rotation speed of the spindle limits the advance / retreat speed of the spindle, so that the operability of the measuring instrument is deteriorated. Further, if the number of changes in the signal per rotation of the spindle is reduced, the resolution of the rotation angle is lowered. There was a problem.

In this respect, in the present invention, since the rotation angle of the spindle can be uniquely determined from one phase signal transmitted from the phase signal transmitting means, it is not necessary to increment the signal as in the conventional case. Therefore, in the present invention, skipping of signals due to high-speed rotation of the spindle is not a problem, so there is no need to limit the rotation speed of the spindle, and high-speed rotation of the spindle is allowed to improve the operability of the measuring instrument. be able to. Thus, even if the spindle rotates at high speed, the rotation angle of the spindle can be obtained from the phase signal from the phase signal transmitting means.
Further, since skipping of the signal does not cause a problem, the change of the phase signal with respect to the rotation of the spindle can be refined.

  Thus, by refining the change of the phase signal with respect to the rotation of the spindle, the resolution with respect to the rotation angle of the spindle can be increased. Further, the phase signal transmitting means only needs to transmit the phase signal at a pitch that does not skip the rotation speed of the spindle in the rotation speed calculation unit, and it is not necessary to increment all the signals as in the conventional increment formula. Signal transmission timing can be reduced, and as a result, power consumption can be reduced.

  Thus, in the present invention, by providing the phase signal transmitting means for transmitting different phase signals for different rotation angles of the spindle, high-speed rotation of the spindle can be allowed, and the resolution of the rotation angle of the spindle is improved. The epoch-making effect that power consumption can be reduced is achieved.

  In the present invention, the phase signal transmitting means includes a rotor that rotates integrally with the spindle, a stator that is provided in the main body in a state of being opposed to the rotor, and that transmits a phase signal corresponding to the rotation angle of the rotor; And the stator detects the rotation of the rotor and transmits a different signal to each other. The first track that transmits the first phase signal as the two detection tracks and the first phase signal change in a different cycle. A second track for transmitting a phase signal, the phase difference between the first phase signal and the second phase signal is different for different rotation angles of the rotor, and the rotation angle calculation unit It is preferable to calculate the rotation angle of the rotor based on this.

In such a configuration, when the spindle rotates, the rotor rotates together with the spindle. Then, the rotation of the rotor is detected by the stator.
Here, the stator is provided with a first track and a second track for transmitting a phase signal. The first phase signal is output from the first track, and the second phase signal is output from the second track. . The first phase signal and the second phase signal exhibit different periodic changes with respect to the rotation of the rotor, and the phase difference between the first phase signal and the second phase signal is different in the rotor rotation angle within one rotation of the rotor. Since the values are different from each other, the rotation angle of the rotor is uniquely determined based on this phase difference.
Since the rotor and the spindle rotate integrally, the rotation angle of the rotor is the rotation angle of the spindle, and the absolute position of the spindle is obtained based on the rotation angle of the spindle.

  According to such a configuration, the rotation angle of the rotor is uniquely determined based on the phase difference between the two phase signals (first phase signal and second phase signal) showing different periodic changes with respect to the rotation of the rotor. can do. Since the phase difference between the two phase signals (the first phase signal and the second phase signal) is different for different rotation angles of the rotor, the first phase signal and the second phase signal are sampled to 2 If the phase difference between the two signals is obtained, the rotation angle of the rotor can be obtained. Therefore, since there is no need to increment the signal in order, the speed of the periodic change of the phase signal does not matter, the high-speed rotation of the spindle is allowed, and the change of the phase signal with respect to the rotation of the spindle is made fine. Thus, the resolution with respect to the rotation angle of the spindle can be increased.

  Since the rotation angle of the rotor only needs to be specified by the phase difference between the plurality of phase signals, it is a matter of course that there may be third and fourth phase signals in addition to the first phase signal and the second phase signal. .

  In the present invention, the stator includes a transmission electrode to which an AC signal is applied and a reception electrode having a predetermined number of detection patterns corresponding to one period of phase change in one unit, and the rotor includes the transmission electrode and the reception electrode. And a coupling electrode having a number of detection patterns corresponding to the receiving electrode.

  In such a configuration, when an AC signal is applied to the transmission electrode, an induction magnetic field is induced around the transmission electrode by the current of the transmission electrode. An induced current is induced in the coupling electrode that is electromagnetically coupled to the transmission electrode by an induced magnetic field induced around the transmission electrode. An induced magnetic field is induced around the coupling electrode by the induced current of the coupling electrode. An induced current is induced in the receiving electrode that is electromagnetically coupled to the coupling electrode by an induced magnetic field induced around the coupling electrode. That is, signals are transferred in the order of transmission electrode → coupling electrode → reception electrode. At this time, since the overlapping degree of the detection pattern of the coupling electrode and the reception electrode varies depending on the rotation angle of the rotor, the signal induced in the reception electrode periodically changes according to the rotation of the rotor. The rotational phase of the rotor can be detected by sampling the signal of the receiving electrode at a predetermined pitch.

  According to such a configuration, the coupling electrode and the receiving electrode are electrode tracks having detection patterns that change periodically, and the coupling electrode and the receiving electrode transmit and receive signals by electromagnetic coupling. Can be configured. For example, the detection pattern of the coupling electrode and the reception electrode can be configured by arranging a plurality of coils, and signals having different phases can be obtained depending on the degree of overlap between the coil pattern of the coupling electrode and the coil pattern of the reception electrode. When the detection pattern is composed of electrode lines, it is easy to form the electrode line pattern finely, so that each coil pattern is made fine so that changes in the phase signal with respect to the rotation of the rotor can be finely defined. It becomes easy to make it. As a result, the resolution with respect to the rotation angle of the rotor can be improved.

In addition, when an electrode plate that is electrostatically coupled is provided on the opposed surfaces of the rotor and the stator as in the prior art and the rotation angle of the rotor is detected by the potential change of these electrode plates, the gap between the rotor and the stator varies. As a result, the potential of the electrode plate fluctuates and the rotation angle of the rotor cannot be accurately detected.
In this respect, in the present invention, the transmission electrode and reception electrode of the stator and the coupling electrode of the rotor exchange signals by electromagnetic coupling, so that the rotation of the rotor is not affected by the gap variation between the stator and the rotor. The corner can be detected accurately.

  In addition, not only when the transmission electrode and the reception electrode are provided on the stator and the coupling electrode is provided on the rotor, conversely, the transmission electrode and the reception electrode may be provided on the rotor, and the coupling electrode may be provided on the stator. The coupling electrode and the reception electrode may be provided on separate members. In short, the transmission electrode, the coupling electrode, and the reception electrode only need to be electromagnetically coupled.

  In the present invention, the main body includes a spindle operation unit for manually operating the rotation of the spindle, and the phase signal transmitting means is configured to rotate the spindle at a maximum rotation speed of the spindle that can be manually operated by the spindle operation unit. It is preferable that the phase signal is sampled at a pitch at which the phase signal is acquired at least three times during one rotation.

  In such a configuration, when the spindle is rotated by manually operating the spindle operation unit, the spindle is rotated. Then, a phase signal is output from the phase signal transmission means. Based on this phase signal, the spindle rotation angle is calculated by the rotation angle calculation unit, and further, the rotation number calculation unit sequentially monitors the rotation angle calculated by the rotation angle calculation unit to calculate the rotation number of the spindle. The When the rotation speed of the spindle is counted by the rotation speed calculation section, the phase signal transmission means needs to transmit the phase signal at such a pitch that the rotation speed calculation section does not skip the rotation speed of the spindle.

  In this respect, in the present invention, if the three phase signals are output from the phase signal transmitting means during one rotation of the spindle at the highest speed by manual operation, the rotation of the spindle can be followed. The number of spindle revolutions is not skipped. On the other hand, the pitch at which the phase signal transmitting means transmits the phase signal may be such that the rotation number calculation unit does not skip the rotation number of the spindle, so that the phase signal transmission unit outputs the phase signal compared to the conventional incremental type. The number of transmissions may be much smaller. Since it is sufficient that the phase signal can be output three times per one rotation of the spindle, the rotation speed of the spindle can be allowed to be as high as the phase detection speed of the phase signal transmitting means. As a result, high-speed rotation of the spindle can be allowed and the operability of the measuring instrument can be improved.

  In the present invention, the number of detection patterns provided on the receiving electrode and the coupling electrode is preferably 9 or more.

  In such a configuration, when the spindle is rotated, the rotor is rotated together with the spindle, and a phase signal is output from the stator in accordance with the rotation angle of the rotor. Based on this phase signal, the rotation angle of the rotor, that is, the rotation angle of the spindle is detected. Since the phase signal transmission means transmits different phase signals for different rotation angles of the spindle, the rotation angle calculation unit uniquely calculates the rotation angle of the spindle from one phase signal. Here, when the rotation phase of the spindle is calculated by incrementing the signal as in the conventional case, the number of changes in the signal per revolution of the spindle is reduced so that the increment is accurately performed in order not to skip the signal. It was like that. Therefore, there has been a problem that the resolution of the rotation angle of the spindle is limited.

  In this regard, in the present invention, there is no need to increment the signal as in the prior art, so skipping of the signal is not a problem, and the change of the phase signal with respect to the rotation of the spindle can be made fine. That is, it is possible to increase the detection patterns of the receiving electrode and the coupling electrode to refine the change of the phase signal with respect to the rotation of the rotor, and to improve the resolution with respect to the rotation angle of the spindle.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be illustrated and described with reference to reference numerals attached to respective elements in the drawings.
(First embodiment)
A first embodiment according to the measuring instrument of the present invention will be described.
FIG. 1 is an overall view of a micrometer 100 as the first embodiment.
FIG. 2 is a sectional view of the micrometer 100.
FIG. 3 is a view showing the shape of the feed screw 310 of the spindle 300.
FIG. 4 is a diagram showing the configuration of the phase signal transmission means 400.

  The micrometer 100 includes a main body 200 having an anvil 213 at one end of a substantially U-shaped frame 212, and is screwed into the other end of the main body 200 to move forward and backward in the axial direction along with the screwing rotation. Spindle 300 that performs phase signal transmission means 400 that outputs a phase signal in accordance with the amount of rotation of spindle 300, arithmetic processing means that performs arithmetic processing on the phase signal to calculate the absolute position of spindle 300, and calculated absolute spindle And a digital display unit 600 as display means for displaying the position.

The main body 200 includes a front tube 210, a rear tube 220, and a spindle operation unit 230 in order from one end side. The front cylinder 210 includes a stem 211 provided at one end side opening and a U-shaped frame 212 provided outside. The U-shaped frame 212 has an anvil 213 disposed on one end side so as to face the spindle 300, the other end is fixed to the front tube 210, and a digital display unit 600 is provided on the surface.
The rear cylinder 220 is connected to the front cylinder 210 at one end, has a female screw 221 that is screwed to the spindle 300 on the inner periphery of the other end, and is slit 222 at the other end, and is fastened with a nut 223 from the outside. Has been.

  The spindle operation unit 230 includes a guide cylinder 231 stacked on the rear cylinder 220, an outer sleeve 232 provided rotatably with respect to the guide cylinder 231, and a friction spring 233 between the outer sleeve 232. A cap cylinder 235 provided on the other end side of the outer sleeve 232 and the thimble 234, and a constant pressure mechanism 240.

  The cap cylinder 235 is connected to the outer sleeve 232 by screwing. As shown in FIG. 2, the constant pressure mechanism 240 includes a support shaft 241 having one end screwed to the outer end of the spindle 300, a first ratchet wheel 242 fixed to the inner periphery of the cap cylinder 235, and a first ratchet wheel. A second ratchet wheel 243 that meshes with 242, a compression coil spring 245 that urges the second ratchet wheel 243 toward the first ratchet wheel 242, and is fixed to the support shaft 241 and abuts against the other end of the guide tube 231. A stopper 246.

  The first ratchet wheel 242 and the second ratchet wheel 243 are formed with saw-tooth teeth that mesh with each other at a constant pitch. In this state, the first ratchet wheel 242 and the second ratchet wheel 243 rotate together. However, if a load of a certain level or more is applied to the meshing surfaces of the first ratchet wheel 242 and the second ratchet wheel 243, the first ratchet wheel 242 rotates. The ratchet wheel 242 idles with respect to the second ratchet wheel 243. The second ratchet wheel 243 is provided so as to be displaceable in the axial direction with respect to the support shaft 241 by the key 244 and not rotatable about the shaft, and the second ratchet wheel 243 and the support shaft 241 rotate integrally.

  The spindle 300 is inserted through the stem 211 and protrudes from one end side of the main body 200 to the outside. A feed screw 310 is provided on the outer periphery of the other end side, and is screwed with the female screw 221 of the rear cylinder 220. The other end side of the spindle 300 is reduced in diameter by a taper and is fitted to the other end of the outer sleeve 232. The spindle 300 is provided with an engagement groove (engagement portion) 320 along the axial direction.

  As shown in FIG. 3, the feed screw 310 is a male screw having a relatively large pitch P and a relatively shallow valley depth d. That is, the pitch P of the feed screw 310 is a large pitch that is at least twice the difference between the outer diameter R and the valley diameter r, but the difference between the outer diameter R and the valley diameter r is 1/5 of the outer diameter R. It is as follows. When viewed along the screw axis A, adjacent thread valleys (thread grooves) are formed at a predetermined interval, and the screw axis lines are cross-sectioned along the screw axis A between adjacent thread valleys. There is a valley (inter-groove) that appears as a straight line along A.

The dimensions of the feed screw 310 are, for example, an outer diameter R of about 7.25 mm to 7.32 mm, a valley diameter r of about 6.66 mm to 6.74 mm, a screw pitch P of about 1 mm to 2 mm, and a vertex angle θ of the screw valley. Is about 55 ° to 65 °, and the lead angle is about 5 °.
The dimensions of the feed screw 310 are not particularly limited, and are appropriately selected depending on how much the lead that is the amount of advance / retreat per rotation of the spindle 300 is set.
For example, the pitch P of the feed screw 310 may be 3 times, 5 times, or 10 times the difference between the outer diameter R and the valley diameter r, and the difference between the outer diameter R and the valley diameter r is 7 minutes of the outer diameter R. It is good also as 1/10 of these.

  The internal thread 221 has thread ridges at the same pitch as the feed screw 310. When the female screw 221 is viewed along the screw axis A, the adjacent thread ridges are formed with a predetermined interval, and the cross section along the screw axis A is along the screw axis A between the adjacent thread ridges. There are mountains that appear as straight lines.

As shown in FIGS. 4 and 5, the phase signal transmitting means 400 is a transmission / reception that controls transmission / reception of signals to / from the stator 410, a stator 410 provided in the main body 200, a rotor 420 disposed opposite to the stator 410, and the stator 410. The controller 430, the engagement groove 320 provided in the spindle 300 along the axial direction, the engagement pin 421 provided in the rotor 420 and engaged with the engagement groove 320, and the engagement pin 421 are engaged with the engagement groove 320. A preload applying means 440 for preloading toward the rotor, and an engagement pin support means 450 for supporting the engagement pin 421 so as to prevent the engagement pin 421 from being pulled out.
In FIG. 4, the stator 410 and the rotor 420 are drawn apart from each other for the sake of clarity.

The stator 410 is fixed to one end of the rear cylinder 220 inside the front cylinder 210, and the rotation of the stator 410 is restricted. A spring 411 is interposed between the stator 410 and the rear cylinder 220, and the stator 410 is urged toward one end side. The rotor 420 includes a rotor bush 423 provided to be rotatable independently from the spindle 300, and is disposed opposite to the stator 410 on the other end side of the rotor bush 423. The rotor bush 423 is urged to the other end side by an adjustment screw 424 screwed into the stem 211. The spindle 300 is disposed so as to be inserted through the stator 410 and the rotor 420.
The configuration of transmission / reception control unit 430 and signal control to stator 410 by transmission / reception control unit 430 will be described later.

  The engagement groove 320 is provided in a straight line parallel to the axis of the spindle 300. The engagement groove 320 has a substantially V-shaped cross section and an apex angle of about 60 ° to about 90 ° (see FIG. 5).

  The engagement pin 421 is inserted into a through hole formed in the rotor bush 423, and has a spherical tip sphere at the tip. The diameter of the tip sphere is about 0.8 mm to 1.5 mm. The tip sphere is engaged with the engagement groove 320.

  The preload applying means 440 is configured by a ring-shaped plate spring 441 formed in a ring shape by winding a single plate spring. The ring-shaped leaf spring 441 may have a discontinuous ring shape in which one end and the other end are separated from each other, or the one end and the other end may overlap. The ring-shaped leaf spring 441 is fitted on the outer surface of the rotor bush 423 in a state where the engagement pin 421 is inserted, and biases the base end of the engagement pin 421 toward the spindle 300. At this time, the small pin 422 protruding from the base end of the engagement pin 421 is inserted into the ring-shaped plate spring 441 so as not to be removable, and the engagement pin 421 is hooked on the ring-shaped plate spring 441.

  Thus, the engagement pin support means 450 is comprised by the engagement pin 421 being latched by the ring-shaped leaf | plate spring 441. FIG. By engaging the engagement pin with the ring-shaped plate spring 441 by the engagement pin support means 450, even when the spindle 300 is pulled out from the rotor 420 as shown in FIG. The position of the engagement pin is substantially maintained without falling off from the rotor bush 423.

Next, the principle of detecting the rotational phase of the rotor 420 by the stator 410 in the phase signal transmission means 400 will be briefly described.
This phase signal transmitting means 400 is a so-called single-rotation ABS (absolute detection) rotary encoder.
FIG. 6 is a diagram showing the opposing surfaces of the stator 410 and the rotor 420.
FIG. 6A is a diagram showing one surface of the stator 410, and FIG. 6B is a diagram showing one surface of the rotor 420.

A surface of the stator 410 facing the rotor 420 is provided with an electrode portion that is doubled on the inside and outside, that is, a first stator electrode portion (first track) 460 is provided on the inside, and the first A second stator electrode portion (second track) 470 is provided outside the stator electrode portion 460 (see FIG. 6A).
The first and second stator electrode portions 460 and 470 are connected to the transmission / reception control portion 430. In the rotor 420, a surface facing the stator 410 is provided with an electrode portion that is doubly arranged on the inside and outside, that is, on the inside, a first coupling electrode portion 480 that electromagnetically couples with the first stator electrode portion 460. And a second coupling electrode portion 490 that electromagnetically couples with the second stator electrode portion 470 (see FIG. 6B).

  The transmission / reception control unit 430 includes a transmission control unit 431 and a reception control unit 432, the transmission control unit 431 transmits a predetermined AC signal to the first and second stator electrode units 460 and 470, and the reception control unit 432 Signals from the first and second stator electrode portions 460 and 470 are received.

First, the first stator electrode portion 460 and the second stator electrode portion 470 will be described with reference to FIG.
The first stator electrode portion 460 forms a first transmission electrode portion 461 composed of one electrode wire arranged in a ring shape, and a rhombus coil that is continuous at a predetermined pitch inside the first transmission electrode portion 461. A first receiving electrode portion 462 that is configured by the electrode wires 462A to 462C and is arranged in a ring shape as a whole.
Similarly, the second stator electrode portion 470 includes a second transmission electrode portion 471 formed of one electrode wire arranged in a ring shape, and a rhombus coil continuous at a predetermined pitch inside the second transmission electrode portion 471, respectively. And a second receiving electrode portion 472 that is configured by three electrode wires 472A to 472C to be formed and arranged in a ring shape as a whole.

The electrode wires (462A to C) constituting the first receiving electrode portion 462 constitute nine (9 periods) rhombuses, and the electrode wires (472A to C) constituting the second receiving electrode portion 472 are Each comprises 10 (10 periods) rhombuses, and in each receiving electrode portion 462, 472, three electrode lines are arranged so as to overlap with a phase shift.
In FIG. 6A, the portions where the wirings appear to cross each other are separated in a direction perpendicular to the paper surface, and insulation is ensured.

  The first receiving electrode portion 462 and the second receiving electrode portion 472 are essentially equivalent to a configuration in which each ring coil is independently connected by a single electrode wire. Equivalent to one coil.

Here, each electrode line of the first and second transmission electrode units 461 and 471 is connected to the transmission control unit 431, and a predetermined AC signal is applied to each electrode line from the transmission control unit 431.
The electrode lines of the first and second reception electrode units 462 and 472 are connected to the reception control unit 432, and the reception control unit 432 samples the signals of the first and second reception electrode units 462 and 472 at a predetermined sampling period. The

Next, with reference to FIG. 6 (B), the 1st coupling electrode part 480 and the 2nd coupling electrode part 490 are demonstrated.
The first coupling electrode portion 480 is configured by electrode wires arranged in a ring shape as a whole while drawing a rectangular wave. Similarly, the second coupling electrode portion 490 is configured by an electrode wire that is drawn in a rectangular shape as a whole while drawing a rectangular wave.
In addition, the 1st coupling electrode part 480 is a rectangular wave of 9 periods, and the 2nd coupling electrode part 490 is a rectangular wave of 10 periods. The rectangular waves of the first coupling electrode unit 480 and the second coupling electrode unit 490 are originally equivalent to a configuration in which ring coils, which are independent from each other, are connected by a single electrode wire, that is, Each square wave is equivalent to one coil.

In this configuration, when current (alternating current) (i ₁ ) is supplied from the transmission control unit 431 to the first transmission electrode unit 461 and the second transmission electrode unit 471, the first and second transmission electrode units 461, An induced magnetic field (B ₁ ) is generated around the electrode line 471.
Since the first stator electrode part 460 and the first coupling electrode part 480 are electromagnetically coupled, and the second stator electrode part 470 and the second coupling electrode part 490 are electromagnetically coupled, the first coupling electrode part An induced current (i ₂ ) is generated in 480 and the second coupling electrode portion 490, and an induced magnetic field (B ₂ , B ₃ ) is generated by the induced current (i ₂ ).

Furthermore, the first coupling electrode unit 480 and the first reception electrode unit 462 are electromagnetically coupled, and the second coupling electrode unit 490 and the second reception electrode unit 472 are electromagnetically coupled. An induced current (i ₃ ) is generated in the electrode lines of the first receiving electrode unit 462 and the second receiving electrode unit 472 due to the magnetic field patterns of the electrode unit 480 and the second coupling electrode unit 490.

  Here, since the first coupling electrode unit 480 and the first receiving electrode unit 462 have nine cycles, the second coupling electrode unit 490 and the second receiving electrode unit 472 have ten cycles, so With respect to the rotation, the first detection phase by the first reception electrode unit 462 shows a change of 10 cycles, and the second detection phase by the second reception electrode unit 472 shows a change of 9 cycles. Therefore, for the rotation angle θ of the rotor 420 (0 ° ≦ θ <360 °), the first phase signal φ1 from the first reception electrode unit 462 and the second phase signal φ2 from the second reception electrode unit 472 are different, During one rotation of the rotor 420, the phase difference Δφ between the first phase signal φ1 and the second phase signal φ2 is different with respect to the rotation angle θ of the different rotor 420. Therefore, conversely, the rotational phase θ within one rotation of the rotor 420 is uniquely determined from the phase difference Δφ between the first phase signal φ1 and the second phase signal φ2.

  Note that the sampling period of the signals for the first reception electrode unit 462 and the second reception electrode unit 472 by the reception control unit 432 is set to about 12.5 ms.

The arithmetic processing unit 500 will be described.
The arithmetic processing unit 500 includes a rotation angle calculation unit 510 that calculates the rotation angle θ of the rotor 420, a rotation number calculation unit 520 that counts and calculates the rotation number of the rotor 420, and a total calculation unit that calculates the total rotation phase of the rotor 420. A rotation phase calculation unit 530 and a spindle position calculation unit 540 that calculates the absolute position of the spindle 300 are provided.

  The rotation angle calculation unit is configured to generate the first phase signal φ1 and the second reception electrode unit by the first reception electrode unit 462 based on the signals of the first reception electrode unit 462 and the second reception electrode unit 472 sampled by the reception control unit 432. The second phase signal φ2 by 472 is obtained, and the rotation angle θ (0 ≦ θ <360 °) of the rotor 420 is calculated based on the difference Δφ between the first phase signal φ1 and the second phase signal φ2.

The rotation number calculation unit 520 monitors the rotation angle θ of the rotor 420 calculated by the rotation angle calculation unit 510 and counts the rotation number of the rotor 420. For example, in the rotation angle calculation unit 510, when the phase θ of the rotor 420 changes from 5 ° → 95 ° → 185 ° → 275 ° → 5 °, it passes 360 ° in the process of changing from 275 ° to 5 °. Therefore, it is counted that the rotor 420 has made +1 rotation.
Similarly, when the phase θ of the rotor 420 changes from 5 ° to 275 °, it means that the rotor 420 has passed 360 ° due to the reverse rotation, so that it is counted that the rotor 420 has rotated −1.

  In this way, the rotational speed calculation unit 520 counts the rotational speed N of the rotor 420 from the rotational speed 0 assuming that the spindle 300 is in the reference position. Total rotation phase calculation section 530 is configured to perform total rotation of rotor 420 based on rotation speed N of rotor 420 counted by rotation speed calculation section 520 and rotation angle θ of rotor 420 calculated by rotation angle calculation section 510. Calculate the phase. For example, if the rotation speed N of the rotor 420 counted by the rotation speed calculation unit 520 is 2 and the rotation angle θ calculated by the rotation angle calculation unit 510 is 45 °, the total rotation phase calculation unit 530 The total rotation phase calculated as described above is 765 ° (= 360 ° × 2 + 45 °).

  The spindle position calculation unit 540 calculates the absolute position of the spindle 300 based on the total rotation phase of the rotor 420 calculated by the total rotation phase calculation unit 530. When the pitch per rotation of the spindle 300 is 2 mm and the total rotational phase of the rotor 420 is 765 °, the absolute position of the spindle 300 is 4.25 mm (= 765 ° ÷ 365 ° × 2 mm).

  Here, the phase signal transmission means 400 and the arithmetic processing unit 500 constitute a detection means for detecting the spindle position.

  The digital display unit 600 displays the absolute position of the spindle 300 calculated by the spindle position calculation unit 540.

The operation of the first embodiment having such a configuration will be described.
First, when the cap cylinder 235 of the spindle operation unit 230 is rotated, the first ratchet wheel 242 is rotated integrally with the cap cylinder 235. The rotation of the first ratchet wheel 242 is transmitted to the second ratchet wheel 243 by the engagement of the first ratchet wheel 242 and the second ratchet wheel 243, and the support shaft 241 rotates together with the second ratchet wheel 243. The spindle 300 rotates together with the support shaft 241, and the spindle 300 is advanced and retracted in the axial direction by screwing between the female screw 221 of the main body 200 (rear cylinder 220) and the feed screw 310 of the spindle 300. When the spindle 300 rotates, the rotor 420 rotates together with the spindle 300 by the engagement pin 421 engaged with the engagement groove 320 of the spindle 300.

The rotation of the rotor 420 is detected by the stator 410, and signals from the electrode lines of the first reception electrode unit 462 and the second reception electrode unit 472 of the stator 410 are sampled by the reception control unit 432.
Then, the rotation angle calculation unit 510 calculates the rotation angle of the rotor 420 based on the phase difference between the first phase signal φ1 of the first reception electrode unit 462 and the second phase signal φ2 of the second reception electrode unit 472. . The rotation angle θ calculated by the rotation angle calculation unit 510 is monitored by the rotation number calculation unit 520, and the rotation number calculation unit 520 counts the rotation number of the rotor 420.

The total rotation phase of the rotor 420 is calculated by the total rotation phase calculation unit 530 from the rotor rotation angle θ calculated by the rotation angle calculation unit 510 and the rotation number of the rotor 420 counted by the rotation number calculation unit 520. Is done. Since the total rotation phase of the rotor 420 calculated by the total rotation phase calculation unit 530 is the total rotation phase of the spindle 300, the total rotation phase of the spindle 300 and the advance / retreat pitch (for example, 2 mm) per one rotation of the spindle are obtained. The absolute position of the spindle 300 is calculated by the spindle position calculator 540.
The calculated spindle position is displayed on the digital display unit 600.

  Here, when the spindle 300 is displaced by the operation by the spindle operation unit 230 and the spindle 300 contacts the object to be measured, the spindle 300 does not advance any further. At this time, if the spindle 300 is forced to rotate, a predetermined load or more is applied between the first ratchet wheel 242 and the second ratchet wheel 243. Then, the first ratchet wheel 242 rotates idly with respect to the second ratchet wheel 243. Due to the idling of the first ratchet wheel 242, the rotation operation of the spindle operation unit 230 is not transmitted to the spindle 300 above a predetermined load, so that the spindle 300 does not press the object under measurement above the predetermined pressure, and Damage is prevented.

According to 1st Embodiment provided with such a structure, there can exist the following effects.
(1) When the rotational phase of the spindle 300 is obtained based on the phase signal from the phase signal transmitting means 400, the phase difference Δφ between the first phase signal φ1 and the second phase signal φ2 is different within one rotation of the spindle 300. Since the values are different with respect to the rotation angle, the rotation angle of the spindle 300 is uniquely determined from the phase difference Δφ.
Therefore, it is not necessary to increment the signal as in the conventional case, and skipping of the signal due to high-speed rotation of the spindle 300 does not cause a problem. Therefore, it is not necessary to limit the rotation speed of the spindle 300, and high-speed rotation of the spindle 300 is allowed. Thus, the operability of the micrometer 100 can be improved.

(2) The rotation angle of the spindle 300 is uniquely determined by the phase signal from the phase signal transmitting means 400, and skipping of the signal is not a problem as in the conventional incremental method. Changes can be refined. Thus, by refining the change of the phase signal with respect to the rotation of the spindle 300, the resolution with respect to the rotation angle of the spindle 300 can be increased. In particular, in this embodiment, the advance / retreat pitch per rotation of the spindle 300 is increased in order to improve the operability. By finely adjusting the change of the phase signal with respect to the rotation of the spindle 300, the rotation angle of the spindle 300 is increased. The spindle displacement can be detected with high resolution by increasing the resolution.

(3) Since the phase signal transmission means 400 only has to transmit the phase signal at a pitch that does not skip the rotation number of the spindle 300 in the rotation number calculation unit 520, the timing of signal transmission is higher than that of the conventional increment type. As a result, power consumption can be reduced.

(4) Since the first and second stator electrode portions 460 and 470 and the first and second combined electrode portions 490 are composed of the electrode wires 462A to C and 472A to 472C, the pattern of the electrode wires is finely defined. It is easy to form. Therefore, the change in the phase signal with respect to the rotation angle of the rotor 420 can be refined to increase the resolution of the rotation angle of the rotor 420. In addition, since the first and second stator electrode portions 460 and 470 and the first and second coupling electrode portions 490 exchange signals by electromagnetic coupling, the first and second stator electrode portions 460 and 470 are affected by a gap variation between the stator 410 and the rotor 420. Therefore, the rotation angle of the rotor 420 can be accurately detected.

(5) Since the engagement pin 421 is pre-pressed toward the engagement groove 320 by the ring-shaped leaf spring 441 (pre-pressure applying means 440), the engagement pin 421 and the engagement groove 320 are surely not spaced. The rotation of the spindle 300 can be transmitted to the rotor 420 accurately. Therefore, the rotation angle of the spindle 300 can be accurately detected by reading the rotation angle of the rotor 420 with the stator 410. If the advance / retreat amount per rotation of the spindle 300 is large, a reading error of a minute rotation angle leads to a detection error of a large spindle position. Therefore, the rotation angle of the spindle 300 can be accurately detected, thereby improving measurement accuracy. Can be made.

(6) Since the position of the engagement pin 421 is maintained even when the spindle 300 is removed from the rotor 420 by the engagement pin support means 450, it is easy to set the spindle 300 with respect to the rotor 420 again. Therefore, the exchange of the spindle 300 can be easily performed.

(7) Since the constant pressure mechanism 240 is provided, when the cap cylinder 235 of the spindle operation unit 230 is rotated and the load is equal to or greater than a predetermined load, the constant pressure mechanism 240 idles and the spindle 300 rotates the cap cylinder 235. Not transmitted. Therefore, the contact pressure when the spindle 300 contacts the object to be measured can be regulated to a predetermined pressure or less. Therefore, the object to be measured is not damaged by the spindle 300. In particular, if the advance / retreat pitch per rotation of the spindle 300 is increased, the spindle 300 is displaced at a high speed, which may damage the object to be measured. In this regard, in this embodiment, the spindle 300 is fixed by the constant pressure mechanism 240. Since it is not rotated above the load, the object to be measured is not damaged by the spindle 300.

(8) The phase signal transmission means 400 is configured to detect absolute rotation angles within one rotation of the spindle 300, and is mainly composed of a rotor 420 that rotates together with the spindle 300 and a stator 410 that detects the rotation angle of the rotor 420. Therefore, the phase signal transmission means 400 can be reduced in size. For example, it is conceivable to use an encoder that detects the absolute position of the spindle 300. However, since the encoder that detects the absolute position of the linear movement is a linear type, the encoder is very large and is a small tool. It is difficult to apply to the meter 100. In this respect, in the present embodiment, only the rotation angle θ of the spindle 300 is absolute detected, so that the rotary phase signal transmitting means 400 can be obtained, and the size can be greatly reduced.

(Modification)
Modifications 1 to 4 of the present invention will be described with reference to FIGS.
The basic configurations of Modifications 1 to 4 are the same as those of the first embodiment, but are characterized by the shape of the engagement pin 421 and the configuration of the preload applying means 440.
First, Modification 1 will be described with reference to FIG. 7. The engagement pin 421 is screwed into the rotor bush 423. And the front-end | tip of the engaging pin 421 is a shape which tapers to a triangle by side view.
The modified example 2 will be described with reference to FIG. 8. The engaging pin 421 is screwed into the rotor bush 423. The tip of the engagement pin 421 has a truncated cone shape. Further, the engagement groove 320 of the spindle 300 has a shape having side walls erected from both ends of the bottom surface in the cross-sectional view of FIG.
In Modification 1 and Modification 2, the engagement pin support means 450 is configured by screwing the engagement pin 421 into the rotor bush 423.

The third modification will be described with reference to FIG. 9. The tip of the engaging pin 421 is a flat surface, and the engaging portion 320 of the spindle 300 is also formed with a flat surface.
The point that a ring-shaped plate spring 441 is fitted from the outside of the rotor bush 423 as the preload applying means 440 is the same as in the first embodiment.

Modification 4 will be described with reference to FIG.
The basic configuration of the modified example 4 is the same as that of the first embodiment. However, the preload applying means 440 has one end fixed to the rotor bushing 423 and the other end connected to the engagement groove 320 with the engagement pin 421. It is comprised by the leaf | plate spring 442 pressed toward. And the engagement pin support means 450 is comprised by the small pin 422 provided in the base end side of the engagement pin 421 being latched by the leaf | plate spring 442. FIG.

The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
The case where the spindle feed screw is a high lead of 1 mm to 2 mm has been described as an example, but the spindle feed screw may be a multi-thread screw.

The phase signal transmission means is not limited to the above-described configuration, and may be any configuration that can absolute-detect the rotation angle within one rotation of the spindle.
The phase signal transmission means only needs to detect the rotation angle of the rotor at a predetermined sampling pitch, and it is only necessary that the rotation angle calculation unit can detect the rotation angle of the rotor without skipping the rotation number of the rotor. For example, it suffices if the rotation angle of the rotor can be detected three times or more while the spindle makes one rotation at the highest possible rotation speed by manual operation.

  The rotation speed calculation unit preferably stores the rotation speed when the measuring instrument is turned off. Then, when the power is turned on again, the absolute position of the spindle can be continuously calculated without returning the spindle to the reference position where the rotational speed is zero.

The measuring instrument of the present invention is not limited to a micrometer, but may be a micrometer head or the like, and may be any measuring instrument in which a spindle as a movable member advances and retreats in the axial direction by rotation.
In the above embodiment, a digital display type micrometer is taken as an example, and the case where the engagement pin support means prevents the pin provided on the rotor of the rotary encoder from coming off has been described, but the present invention is not limited to the digital display type micrometer. .
For example, in a measuring instrument equipped with a spindle that advances and retracts by screwing rotation, such as a mechanical micrometer or a micrometer head, the amount of spindle advancement and retraction (rotation amount) is graduated on the outer surface of the main body (200). It may be a mechanical measuring device of the type that reads.
In such a case, when the member rotating with the spindle is engaged with the spindle by the engagement pin, the engagement pin is supported by the engagement pin support means of the present invention. As a result, the engagement pin is prevented from coming off, so that the spindle can be easily exchanged.

  The present invention can be used for a measuring instrument.

The figure which shows the whole structure of the micrometer as 1st Embodiment. Sectional drawing of 1st Embodiment. The figure which shows the shape of the feed screw of a spindle in 1st Embodiment. The figure which shows the structure of a phase signal transmission means in 1st Embodiment. The figure which shows the state of engagement with an engaging pin and an engaging groove in sectional drawing. The figure which shows a stator and a rotor in 1st Embodiment. The figure which shows the modification 1. FIG. The figure which shows the modification 2. FIG. The figure which shows the modification 3. The figure which shows the modification 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Micrometer, 200 ... Main body, 210 ... Front cylinder, 211 ... Stem, 212 ... U-shaped frame, 213 ... Anvil, 220 ... Rear cylinder, 222 ... Slotting, 223 ... Nut, 230 ... Spindle operation part 231 ... guide cylinder, 232 ... outer sleeve, 233 ... friction spring, 234 ... thimble, 235 ... cap cylinder, 240 ... constant pressure mechanism, 241 ... support shaft, 242 ... first ratchet wheel, 243 ... second ratchet wheel, 244 ... key, 245 ... compression coil spring, 246 ... stopper, 300 ... spindle, 320 ... engagement groove, 400 ... phase signal transmission means, 410 ... stator, 411 ... spring, 420 ... rotor, 421 ... engagement pin, 422 ... small Pins, 423 ... rotor bush, 430 ... transmission / reception control unit, 431 ... transmission control unit, 432 ... reception control unit, 440 Pre-pressure applying means, 441 ... ring-shaped leaf spring, 442 ... leaf spring, 450 ... engagement pin support means, 460 ... first stator electrode portion, 461 ... first transmitting electrode portion, 462 ... second receiving electrode portion, 462A -C ... electrode wire, 470 ... second stator electrode portion, 471 ... second transmission electrode portion, 472 ... second reception electrode portion, 472A-C ... electrode wire, 480 ... first coupling electrode portion, 490 ... second coupling Electrode unit 500... Arithmetic processing unit 510. Rotation angle calculation unit 520... Rotation number calculation unit 530... Total rotation phase calculation unit 540... Spindle position calculation unit 600.

Claims (6)

The body,
A spindle screwed into the main body and provided so as to freely advance and retract in the axial direction by rotation;
Phase signal transmission means for transmitting phase signals of different values for different rotation angles of the spindle according to the rotation of the spindle;
Arithmetic processing means for calculating the absolute position of the spindle by calculating the phase signal;
The spindle has an engaging portion provided along the axial direction,
The phase signal transmitting means is
A rotor that rotates integrally with the spindle;
A stator that is provided in the main body in a state of facing the rotor and transmits a phase signal according to a rotation angle of the rotor;
An engagement pin provided on the rotor and engaged with the engagement portion;
And a engagement pin support means for preventing the engagement pin from coming off from the rotor. The measuring instrument according to claim 1, wherein
The phase signal transmitting means is
A measuring instrument comprising preload applying means for preloading the engaging pin toward the engaging portion. The measuring instrument according to claim 2,
The engagement pin is slidable in a direction perpendicular to the axial direction of the spindle with respect to the rotor,
The preload applying means is constituted by a leaf spring that is hooked on the rotor and biases the engaging pin toward the engaging portion. The measuring instrument according to claim 3,
The measuring device, wherein the engaging pin support means is configured by engaging the engaging pin with the leaf spring. The measuring instrument according to any one of claims 1 to 4,
The spindle is displaced by 1 mm or more per rotation. The measuring instrument according to any one of claims 1 to 5,
The main body includes a spindle operation unit for manually operating rotation of the spindle,
The spindle operation unit includes a cap cylinder that is rotatably provided on the outer surface of the main body,
When the load provided between the cap cylinder and the spindle and acting between the cap cylinder and the spindle is less than a predetermined value, the rotation of the cap cylinder is transmitted to the spindle, and the load is predetermined. And a constant pressure mechanism that idles between the cap cylinder and the spindle when the value is equal to or greater than the value.

Images