JP3725151B2 - Micrometer - Google Patents

Description

  The present invention relates to a digital display type micrometer. More specifically, the present invention relates to a micrometer in which the spindle is displaced in the axial direction while rotating, and the cost is reduced and the operability is improved.

Compared with a mechanical scale display type measuring instrument, an electronic digital display type measuring instrument is becoming widespread in general measuring instruments because of its high accuracy and easy reading.
Even in the case of a micrometer, digital display incorporating a rotary encoder has been advanced for a type in which the spindle is displaced in the axial direction as the thimble rotates.

Therefore, the structure of a conventional digital display micrometer will be described with reference to FIG.
In FIG. 7, an anvil 2 is fixed to the inner surface of one end portion of a frame 1 as a main body formed in a substantially U shape, and is displaced relative to the anvil 2 while being displaced in the axial direction at the other end portion. An advancing / retreating spindle 21 is provided. 4 is a digital display for digitally displaying the displacement amount of the spindle 21, 5 is a power on / off switch, and 6 is a zero set switch.

  A bearing cylinder 11 is fixed to the inner surface of the other end of the frame 1 on which the spindle 21 is provided, and a holding ring 12 is screwed to the outer surface. At the center of the holding ring 12, one end of an inner sleeve 13 and an outer sleeve 14 that are fitted in a double cylinder structure inside and outside is held. The inner sleeve 13 has a small-diameter cylindrical portion 13A on one end side, and the other end side 13B is formed in a cylindrical shape that can be expanded and contracted in the radial direction by a plurality of slits 15 formed along the axial direction. On the other end side 13B, an internal thread portion 16 is formed along the axial direction on the inner peripheral surface, and an external thread portion 18 into which the taper nut 17 is screwed is formed on the outer peripheral surface. The spindle 21 is screwed to the female thread portion 16.

  The spindle 21 includes a shaft portion 21A that is slidably supported by the bearing cylinder 11, a screw portion 21B that is formed slightly larger in diameter than the shaft portion 21A and has a screw formed on the outer peripheral surface thereof, and the screw portion. And a tapered portion 21C formed integrally with the other end of 21B. A groove 22 having a V-shaped cross section is formed along the outer peripheral axis direction of the shaft portion 21A. The screw portion 21B is screwed to the female screw portion 16. The other end portion of the thimble 23 that is rotatably fitted to the outer peripheral surface of the outer sleeve 14 is fitted and fixed to the tapered portion 31C. At the other end of the thimble 23, there is provided a ratchet knob 24 that idles when a certain load is applied to the spindle 21. Accordingly, when the thimble 23 or the ratchet knob 24 is rotated, the spindle 21 is displaced in the axial direction while rotating. At this time, the amount of displacement of the spindle 21 is determined from the main scale 25 formed at regular intervals along the outer peripheral surface axial direction of the outer sleeve 14 and the vernier scale 27 formed along the outer periphery of the thimble 23. Can be read.

  A rotating cylinder 31, a first spacer 32, and a second spacer 33 are fitted on the outer periphery of the spindle 21 between the end surface of the small-diameter cylindrical portion 13A of the inner sleeve 13 and the bearing cylinder 11 so as to be sequentially displaceable in the axial direction. In addition, a spring 34 for urging the second spacer 33, the first spacer 32, and the rotating cylinder 31 in the right direction in FIG. 7 is inserted between the second spacer 33 and the bearing cylinder 11. A screw 35 having a projection 35 </ b> A that is slidably engaged with the groove 22 is screwed into the rotating cylinder 31. Thereby, the rotating cylinder 31 and the spindle 21 are rotated synchronously, and displacement of the spindle 21 in the axial direction is allowed.

  An encoder 41 that detects the amount of axial displacement of the spindle 21 from the amount of rotation of the spindle 21 is provided between the small-diameter cylindrical portion 13A of the inner sleeve 13 and the rotating cylinder 31. The encoder 41 is fixed to the plate 42 fixed to the holding ring 12 and has a fixed plate 43 having a transmission electrode and an output electrode (not shown), and is opposed to the rotary plate 31 with a fixed gap. And a rotating plate 44 having a receiving electrode and a coupling electrode (not shown) that are bonded and fixed to each other, and when a signal having a different phase is applied to the transmitting electrode, it corresponds to the relative rotation angle between the fixed plate 43 and the rotating plate 44 Signal to be obtained. A signal corresponding to the relative rotation angle between the fixed plate 43 and the rotating plate 44 detected by the encoder 41 is processed by an electric circuit (not shown) and then digitally displayed on the digital display 4.

  The above-described conventional digital display micrometer has a mechanical scale display mechanism so that it can be used even when the life of the power source (battery) for driving the digital display 4, the encoder 41, and the electric circuit is exhausted. It is. That is, the outer sleeve 14 is provided on the frame 1 side, the thimble 23 is provided on the spindle 21 side, the main scale 25 is provided along the outer peripheral surface axial direction of the outer sleeve 14, and the minor scale 27 is provided along the outer periphery of the thimble 23. It has a formed structure. As a result, the assembly is complicated and the cost is high.

  In the conventional structure, for measurement, for example, the object to be measured is held with the left hand, the frame 1 is gripped with the right hand, and the spindle 21 is moved away from the anvil 2 while turning the ratchet knob 24 with the thumb and index finger of the right hand. As it is displaced, the ratchet knob 24 gradually moves away from the frame 1, so that there is a drawback that it becomes difficult to operate when the spindle 21 is greatly displaced.

  An object of the present invention is to provide a micrometer capable of eliminating the conventional drawbacks, reducing costs, and improving operability.

Micrometer of the present invention includes a body having an anvil at one end, a spindle displaced in the axial direction while rotating with the screwed its screwing rotation to the other end of the body, the spindle from the rotation amount of the spindle In a micrometer including an encoder for detecting an axial displacement amount and a digital display for digitally displaying a measurement value based on an output signal of the encoder, a thimble is fixed on the other end side of the main body in the axial direction of the spindle. And a rotation transmitting means for transmitting the rotation of the thimble between the thimble and the spindle to the spindle to rotate the spindle and permitting axial displacement of the spindle. The rotation transmission means transmits rotation of the thimble to the spindle; More than predetermined load to the spindle is a ratchet mechanism for idling the thimble to the spindle when applied, the thimble is characterized in that it is configured to include a cap for covering the other end of the spindle

According to such a configuration, since the main scale and the sub-scale, which are provided in the conventional micrometer, are omitted, the costs associated with the processing can be reduced. In addition, since the outer sleeve for forming the main scale can be eliminated, the number of parts and the number of assembly steps can be reduced. Therefore, the cost can be reduced.
In the measurement, when the thimble is rotated, the rotation of the thimble is transmitted to the spindle via the rotation transmission means. Since the spindle is screwed into the main body, it is displaced in the axial direction as it rotates. Then, after the displacement amount of the spindle is detected by the encoder, it is digitally displayed on the digital display. At this time, even if the spindle is displaced in a direction away from the anvil, the thimble is rotatably provided at a fixed position of the main body, that is, the thimble is not displaced together with the spindle. However, it is possible to solve the problem that the operability is lowered.

Moreover, rotation transmission means is configured to transmit the rotation of said thimble to the spindle, because more than predetermined load to the spindle there is a ratchet mechanism for idling the thimble to the spindle when applied, the spindle and the anvil When the object to be measured is clamped and a load of a certain level or more is applied to the spindle, the thimble is idled with respect to the spindle. Therefore, highly accurate measurement can be ensured.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same components as those in FIG. 7 described above are denoted by the same reference numerals, and the description thereof is omitted or simplified.
In the micrometer of this embodiment, as shown in FIGS. 1 and 2, the outer sleeve 14 is omitted, and a sleeve 51 shorter than the inner sleeve 13 is held by the holding ring 12. . In the other end portion of the sleeve 51, a nut member 52 having a female screw formed on the inner peripheral surface is press-fitted and fixed. A spindle 61 is screwed into the nut member 52.

  The spindle 61 includes a shaft portion 61A that is slidably supported by the bearing cylinder 11, and a screw that is formed to have the same diameter as the shaft portion 61A and that has an external thread that engages with the nut member 52 on the outer peripheral surface. Part 61B. A V-shaped groove 62 with which the projection 35A of the screw 35 engages is formed along the axial direction from the middle of the shaft portion 61A to the entire length of the screw portion 61B.

  A cylindrical thimble 71 having a flange portion 71A at one end is provided on the outer periphery of the sleeve 53 so as to be rotatable about the axis of the spindle 61, and the collar portion 71A is fitted from the outside to fit the thimble 71. A cap nut 72 that holds the screw in a fixed position in the axial direction is screwed. The thimble 71 includes a cylindrical body 73 that is supported on the outer periphery of the sleeve 51 so as to be rotatable about the axis of the spindle 61, and a cap that is screwed to the other end of the cylindrical body 73 and covers the other end side of the spindle 61. 74. The inner diameter of the cap 74 is formed to be slightly larger than the outer diameter of the spindle 61, and also serves as a stopper that abuts on an end face of a leaf spring 85 described later when screwed into the other end of the cylindrical body 73.

  Between the thimble 71 and the spindle 61, there is provided rotation transmission means 81 that transmits the rotation of the thimble 71 to the spindle 61 and allows the axial displacement of the spindle 61. Here, a ratchet mechanism 82 that transmits the rotation of the thimble 71 to the spindle 61 and idles the thimble 71 with respect to the spindle 61 when a load exceeding a certain level is applied to the spindle 61 is used as the rotation transmitting means 81. ing.

  3 and 4, the ratchet mechanism 82 includes a ratchet ring 84 that is fixed in the thimble 71 and has a serrated projection 83 on the inner peripheral surface, and an outer peripheral surface of the ratchet ring 84 and the spindle 61. Between one end 85 </ b> A and the other end 85 </ b> B against the sawtooth projection 83 of the ratchet ring 84. The plate spring 85 is biased.

In the above configuration, when assembling, the cap 74 is removed from the cylinder 73 of the thimble 71, and the ratchet mechanism 82 is incorporated in the cylinder 73. That is, after the ratchet ring 84 is press-fitted and fixed, the leaf spring 85 is inserted along the ratchet ring 84.
The cylinder 73 in this state is fitted on the outer periphery of the sleeve 51, and a cap nut 72 is screwed from the outside to hold the cylinder 73 rotatably. At this time, while looking through the hole at the other end of the cylindrical body 73, the cylindrical body 73 is rotatably held while rotating and adjusted so that one end 85 </ b> A of the leaf spring 85 fits into the groove 62 of the spindle 61. Thereafter, the cap 74 is screwed onto the cylinder 73.

  In measurement, for example, when holding the object to be measured (not shown) with the left hand, holding the frame 1 with the right hand, and rotating the thimble 71 with the thumb and index finger of the right hand, the rotation of the thimble 71 causes the ratchet mechanism 82 to rotate. And transmitted to the spindle 61. Then, since the spindle 61 is screwed into the nut member 52 provided on the frame 1 side, the spindle 61 is displaced in the axial direction as it rotates. Then, the displacement amount of the spindle 61 is detected by the encoder 41 and then digitally displayed on the digital display 4.

  If the object to be measured is sandwiched between the anvil 2 and the spindle 61 while the spindle 61 is displaced, the spindle 61 cannot be displaced further in the direction approaching the anvil 2, that is, rotate in the same direction. Therefore, the ratchet ring 84 idles with respect to the leaf spring 85 of the ratchet mechanism 82. Therefore, if the display value of the digital display 4 at this time is read, measurement can be performed at a constant measurement pressure.

  According to the present embodiment, the main scale and the sub-scale, which are provided in the conventional micrometer, are omitted, so that an outer sleeve for forming the main scale can be eliminated. Therefore, the costs associated with these processes can be reduced, and the number of parts and the number of assembling steps can be reduced, so that the cost can be reduced.

  Further, the thimble 71 is rotatably provided on the other end side of the frame 1 via the sleeve 51, and the rotation transmitting means 81 is provided between the thimble 71 and the spindle 61. Therefore, the thimble 71 is rotated for measurement. Then, since the rotation of the thimble 71 is transmitted to the spindle 61 via the rotation transmitting means 81, the spindle 61 is displaced in the axial direction. Then, the displacement amount of the spindle 61 is detected by the encoder 41 and then digitally displayed on the digital display 4. At this time, even if the spindle 61 is displaced in a direction away from the anvil 2, the thimble 71 is rotatably provided at a fixed position of the frame 1, that is, the thimble 71 is not displaced together with the spindle 61. Even if the spindle 61 is greatly displaced, the problem that the operability is lowered can be solved.

Further, since the rotation transmitting means 81 is constituted by the ratchet mechanism 82, when the measured object is sandwiched between the spindle 61 and the anvil 2 and a load of a certain level or more is applied to the spindle 61, the thimble 71 is idled with respect to the spindle 61. Therefore, measurement can always be performed at a constant measurement pressure. Therefore, highly accurate measurement can be ensured.
Further, the ratchet mechanism 82 is fixed in the thimble 71 and has a serrated projection 83 on its inner peripheral surface, and a leaf spring 85 inserted between the ratchet ring 84 and the outer peripheral surface of the spindle 61. Therefore, the number of parts can be reduced to a compact size, the assembly is advantageous, and the cost can be reduced. Moreover, since the leaf spring 85 is biased in the direction of opening outward, the threaded portion 61B of the spindle 61 is rarely damaged.

Further, since the thimble 71 is composed of a cylindrical body 73 rotatably supported on the other end side of the frame 1 and a cap 74 screwed to the other end of the cylindrical body 73, the leaf spring of the ratchet mechanism 82 When one end 85A of 85 is locked to the groove 62 of the spindle 61, the work can be performed while looking through the hole of the cylindrical body 73, so that the one end 85A of the leaf spring 85 can be easily locked to the groove 62 of the spindle 61. The groove 62A also serves as a groove that allows the spindle 61 to be displaced in the axial direction while rotating the rotary cylinder 31 synchronously with the spindle 61. Therefore, the groove 62A is a groove for locking the one end 85A of the leaf spring 85. No special processing is required.
In addition, since the inner diameter of the cap 74 is slightly larger than the outer diameter of the spindle 61, when the spindle 61 is displaced in the axial direction, the leaf spring 85 also tries to move in the axial direction. Therefore, the leaf spring 85 can be held in a fixed position.

In the embodiment described above, the ratchet mechanism 82 is used as the rotation transmitting means 81. However, any other structure can be used as long as it can transmit the rotation of the thimble 71 to the spindle 61 and allow the axial displacement of the spindle 61. But you can.
For example, as shown in FIGS. 5 and 6, a groove 62A having a rectangular cross section is provided along the axial direction of the spindle 61, and a pin 91 slidably engaged with the groove 62A is provided on the inner surface of the thimble 71. The structure may be sufficient. Even in such a structure, the rotation of the thimble 71 is transmitted to the spindle 61 via the pin 91 and the groove 62A, and the axial displacement of the spindle 61 can be allowed by the groove 62A engaged with the pin 91.

  The form of the encoder 41 is not limited to the rotary encoder comprising the fixed plate 43 and the rotating plate 44 described in the above embodiment, but a cylindrical encoder having a coaxial cylindrical structure (for example, Japanese Patent Application No. 6-330689). Or the like). Furthermore, not only the electrostatic capacity type encoder but also a photoelectric type or a magnetic type may be used.

  The present invention can be used for a digital display type micrometer.

It is the front view which notched one part which shows one Embodiment of the micrometer concerning this invention. It is an enlarged view which shows the principal part of embodiment same as the above. It is the III-III sectional view taken on the line of FIG. It is a disassembled perspective view which shows the ratchet mechanism of embodiment same as the above. It is an enlarged view which shows the principal part of other embodiment of the micrometer concerning this invention. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. It is the front view which notched a part which shows the conventional digital display type | mold micrometer.

Explanation of symbols

1 ... Frame (body)
2 ... anvil 4 ... digital display 41 ... encoder 61 ... spindle 62 ... groove 71 ... thimble 73 ... cylinder 74 ... cap 81 ... rotation transmission means 82 ... ratchet mechanism 83 ... serrated projection 84 ... ratchet ring 85 ... leaf spring 85A ... One end of leaf spring 85B ... The other end of leaf spring

Claims (1)

Detecting a body having an anvil at one end, a spindle displaced in the axial direction while rotating with the screwed its screwing rotation to the other end of the body, the axial displacement of the spindle from the rotation amount of the spindle In a micrometer comprising an encoder and a digital display for digitally displaying a measurement value based on the output signal of the encoder,
A thimble is provided at the other end side of the main body at a fixed position in the axial direction of the spindle and rotatable about the spindle axis,
A rotation transmitting means is provided between the thimble and the spindle to transmit the rotation of the thimble to the spindle to rotate the spindle, and to allow axial displacement of the spindle,
The rotation transmission means is a ratchet mechanism that transmits rotation of the thimble to the spindle and idles the thimble with respect to the spindle when a load of a certain level or more is applied to the spindle.
The thimble is configured to include a cap that covers the other end side of the spindle .

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