JP4690028B2 - Caliper type micrometer - Google Patents

Description

  The present invention relates to a caliper type micrometer. Specifically, in a general micrometer, a pair of measurement claws are attached to the main body and the tip of a forward / backward rod that advances and retreats with respect to the main body, and is opposed to each other and perpendicular to the axis of the forward / backward rod. The present invention relates to a caliper type micrometer that measures the inner dimension and the outer dimension of the object to be measured by bringing the object into contact with the measurement site of the object to be measured.

A caliper type micrometer is known that uses the micrometer mechanism to measure the inner dimension of the object to be measured, or to measure the object to be measured in a narrow space (for example, Patent Document 1). reference).
As shown in FIG. 5, the caliper-type micrometer is a general micrometer that is provided so that it can be advanced and retracted at one end side (anvil side) of the U-shaped main body frame 1 and at the other end of the main body frame 1. A pair of measuring claws 2, 13 are attached to the tip of the rod 10 so as to face each other and at right angles to the axis of the advance / retreat rod 10, and the rotation of the thimble 43 prevents the advance / retreat rod 10 from rotating. It is configured to move forward and backward.

Conventionally, the structure shown in FIG. 6 or the structure shown in FIG. 7 has been adopted as a mechanism for the advance / retreat rod 10 to advance and retract in the axial direction without rotating.
In the structure shown in FIG. 6, a V groove 101 is formed along the axial direction on the outer peripheral surface of the advance / retreat rod 10, and the advance / retreat rod 10 is attached to the main body frame 1 (specifically, the bearing cylinder 3 provided on the main body frame 1). A screw hole 102 orthogonal to the axis is formed, and a first screw 103 having a conical key 103A at the tip and a normal second screw 104 are screwed into the screw hole 102.
In the structure shown in FIG. 7, a V groove 101 is formed along the axial direction on the outer peripheral surface of the advance / retreat rod 10, and the advance / retreat rod 10 is attached to the main body frame 1 (specifically, the bearing tube 3 provided on the main body frame 1). A screw hole 102 perpendicular to the axis is formed, and a cylindrical body 106 having an engagement piece 105 having a protrusion 105A having a trapezoidal cross section at the tip is screwed into the screw hole 102. The cap 107 is screwed to the outer end.

Japanese Utility Model Publication No. 39-22286

  In any of the above-described structures, when an impact is applied from the outside, the screws 103 and 104 and the cylindrical body 106 are loosely screwed by the impact, and the conical key 103A and the trapezoidal protrusion 105A are lifted from the V groove 101. It may become a state. In such a state, a clearance is created between the V-groove 101 and the key 103A or the protrusion 105A, so that the advance / retreat rod 10 is rotated by the clearance. Then, the measuring claw 13 on the advancing / retracting rod 10 side rotates about the axis of the advancing / retreating rod 10, so-called measurement claw play occurs. Arise.

  This is because not only when an impact is applied from the outside, but also when the measuring rod is used, the forward / backward rod 10 repeats forward / backward movement in the axial direction. Therefore, the conical key 103A and the trapezoidal ridge 105A always have V Since a force floating from the V-groove 101 works through the groove 101, it is a problem caused by use. In particular, the conventional V-groove 101 has a V-groove angle of 60 °. Therefore, the component force in the direction of floating the conical key 103A and the trapezoidal ridge 105A from the V-groove 101 is large. This is a possible problem.

  It is an object of the present invention to provide a caliper type micrometer that can eliminate such conventional drawbacks and can reduce the occurrence of backlash of a measuring claw.

The caliper type micrometer of the present invention includes a main body, an advancing / retracting rod provided on the main body through a linear guide mechanism so as not to be rotatable and capable of moving back and forth in the axial direction, and a front end of the advancing / retreating rod and the main body. And a pair of measuring claws provided at right angles to the axis of the advance / retreat rod, a spindle screwed to the main body, and a thimble provided integrally with the spindle. In the caliper type micrometer equipped with an advance / retreat mechanism for moving the advance / retreat rod in the axial direction, the linear guide mechanism is formed along the axial direction on the outer peripheral surface of the advance / retreat rod, and the groove width increases toward the inside from the outer peripheral surface. and a cross-sectional trapezoidal shape of the key groove gradually narrowed, is slidably configured to include a key frustoconical engaging said keyway provided in the body, before Wherein the angle formed by the lateral walls of the keyway is formed in the range of 7 ° to 30 °.

Here, the diameter of the key at the maximum groove width and maximum groove width position of the key groove, the range of 1.2Mm～2.4Mm, preferably in the range of 1.4Mm～2.2Mm, more preferably 1. It is good to form in the range of 6 mm-2.0 mm.

  According to this configuration, when the thimble of the advance / retreat mechanism is turned, the spindle integrated with the thimble is displaced in the axial direction while rotating. Then, the advance / retreat rod is restricted in rotation by the linear guide mechanism and can move only in the axial direction, so that it is displaced in the axial direction together with the spindle. After the pair of measuring claws are brought into contact with the measurement site of the object to be measured by the axial displacement of the advancing / retreating rod, the value of the means for displaying the displacement of the advancing / retreating rod (for example, a digital display or scale) can be read. Thus, the dimension of the object to be measured can be measured.

In the present invention, the linear guide mechanism includes a key groove having a trapezoidal cross section formed along the axial direction on the outer peripheral surface of the advance / retreat rod, and a frustoconical key that slidably engages with the key groove. Therefore, it is possible to reduce the occurrence of play of the measuring claw as compared with the conventional structure.
In particular, the angle formed by the side walls on both sides of the key groove is in the range of 7 ° to 30 °. Therefore, compared to the conventional V groove (V groove angle is 60 °), the component force in the direction of floating the key from the key groove is also Since it is small, it is possible to reduce the occurrence of play of the measurement nail.
In addition, since the angle formed by the side walls on the both sides of the key groove is in the range of 7 ° to 30 °, the key groove depth dimension tolerance can be increased in comparison with the conventional V groove processing. In other words, if the groove width is to be controlled within the specified dimension, the angle formed by the side wall of the trapezoidal key groove is smaller (7 ° to 30 °) than the angle of the conventional V groove (60 °). The tolerance of the groove depth can be increased.
Further, since the maximum groove width dimension of the key groove and the key diameter dimension at the maximum groove width position are formed to be 1.2 mm to 2.4 mm, the conventional V groove (V groove angle is 60 °). Compared to a conical key or a conical key, the cross-sectional area can be increased, and therefore the strength can be increased.

In the caliper type micrometer of the present invention, the main body is formed with a screw hole orthogonal to the axial direction of the advance / retreat rod, and a first screw having the key at the tip is screwed into the screw hole. It is preferable.
Further, it is preferable that the second screw is screwed into the screw hole in contact with the rear end of the first screw.
According to this configuration, by screwing the first screw, it is possible to adjust the degree to which the key at the tip is fitted into the key groove, and thus it is possible to ensure an appropriate sliding resistance. That is, it is possible to secure a fitting state in which the advance / retreat rod can smoothly move in the axial direction without rotating. Furthermore, if the first screw and the second screw are screwed in series, the looseness of these screws can be reduced, so that an appropriate fitting state can be maintained for a long period of time.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
<Description of FIG. 1>
FIG. 1 shows a main part of the caliper type micrometer of the present embodiment.
Although only a part of the caliper type micrometer is shown in FIG. 1, the caliper type micrometer includes a frame 1 as a main body formed in a substantially U shape similar to the frame 1 of FIG. Although not shown, the measurement claw 2 shown in FIG. 5 is fixed to one end of the frame 1, and the bearing cylinder 3 is fixed to the other end, and the bearing cylinder 3 is connected to the bearing cylinder 3 via a linear guide mechanism 70. An advancing / retracting rod 10 is provided so as to be able to advance and retract in the axial direction and toward the measuring claw 2.

  The advancing / retracting rod 10 is a columnar first rod portion 11 that is movably supported by the bearing cylinder 3, and a columnar shape that is integrally connected to the rear end of the first rod portion 11 and is thinner than the first rod portion 11. The second rod portion 12 is provided. A measurement claw 13 shown in FIG. 5 is provided at the tip of the first rod portion 11 so as to face the measurement claw 2 and at a right angle to the axis of the advance / retreat rod 10. A taper receiving piece 14 is screwed to the end of the second rod portion 12.

  An indicator mounting plate 20 is screwed into the outer end portion of the bearing tube 3. The display mounting plate 20 is provided with a digital display 21 for digitally displaying the amount of displacement of the advance / retreat rod 10 and various switches such as a power on / off switch 22, a zero set switch 23, an inch / mm switch 24, and the like. The holding ring 25 is screwed to the outer surface side. One end of an inner sleeve 30 and an outer sleeve 35 that are fitted in a double cylinder structure inside and outside is held at the center of the holding ring 25.

The other end 30B of the inner sleeve 30 is formed in a cylindrical shape that can be expanded and contracted in the radial direction by a plurality of slits (not shown) formed along the axial direction. On the other end side 30B, an internal thread portion 32 is formed along the axial direction on the inner peripheral surface thereof, and an external thread portion 34 into which the taper nut 33 is screwed is formed on the outer peripheral surface. A spindle 40 is screwed into the female thread portion 32.
A main scale (not shown) is engraved on the outer peripheral surface of the outer sleeve 35 at a constant pitch along the axial direction.

  The spindle 40 has a length corresponding to the second rod portion 12 of the advance / retreat rod 10 (specifically, the length from the boundary position between the first rod portion 11 and the second rod portion 12 to the taper receiving piece 14). It is formed in a shape and is rotatably inserted into the outer periphery of the second rod portion 12. In the spindle 40, a V-groove 41 is formed along the axial direction on the outer peripheral surface on one end side from the intermediate position in the longitudinal direction, and a screw 42 is formed on the outer peripheral surface in front of the other end side from the intermediate position. The other end portion of the thimble 43 that is rotatably fitted to the outer peripheral surface of the outer sleeve 35 is fitted and fixed to the outer peripheral surface via a taper bush 44. The taper bush 44 is screwed with a tightening nut 45 for fixing the thimble 43 to the taper bush 44, and the tightening nut 45 is provided with a ratchet knob 46 that rotates idly when a certain load is applied to the advance / retreat rod 10. It has been.

  Thereby, when the thimble 43 or the ratchet knob 46 is rotated, the spindle 40 is displaced in the axial direction while rotating. Then, the advance / retreat rod 10 is advanced and retracted in the axial direction together with the spindle 40. At this time, the amount of displacement of the advance / retreat rod 10 can be read from a main scale formed on the outer peripheral surface of the outer sleeve 35 and a vernier scale 47 formed along the outer periphery of the thimble 43. Here, a spindle 40 screwed to the inner sleeve 30 and a thimble 43 provided integrally with the spindle 40 are included. It is configured.

  A rotating cylinder 51, a first spacer 52, and a second spacer 53 are fitted on the outer periphery of the spindle 40 between the one end surface of the inner sleeve 30 and the bearing cylinder 3 so as to be sequentially displaceable in the axial direction. A spring 54 for urging the second spacer 53, the first spacer 52, and the rotating cylinder 51 in the right direction in FIG. 1 is inserted between the two spacers 53 and the bearing cylinder 3. A screw 55 having a protrusion 55 </ b> A that is slidably engaged with the V-groove 41 is screwed into the rotating cylinder 51. Thereby, the rotating cylinder 51 and the spindle 40 are rotated synchronously, and displacement of the spindle 40 in the axial direction is allowed.

  An encoder 60 is provided between one end of the inner sleeve 30 and the rotating cylinder 51 to detect the amount of axial displacement of the spindle 40 from the amount of rotation of the spindle 40. The encoder 60 is bonded and fixed to a plate 62 fixed to the holding ring 25 and has a transmission electrode and an output electrode (not shown), and is bonded to the rotating cylinder 51 in a state of facing the fixed plate 63 with a certain gap. A signal corresponding to the relative rotation angle between the fixed plate 63 and the rotating plate 64 from the output electrode when signals having different phases are applied to the transmitting electrode, including a rotating plate 64 that is fixed and has a receiving electrode and a coupling electrode (not shown). Can be obtained. A signal corresponding to the relative rotation angle between the fixed plate 63 and the rotating plate 64 detected by the encoder 60 is processed by an electric circuit (not shown) and then digitally displayed on the digital display 21.

<Description of FIGS. 2 and 3>
2 is an enlarged view of the linear guide mechanism 70, and FIG. 3 is a cross-sectional view taken along line III-III in FIG.
The linear guide mechanism 70 includes a key groove 71 formed along the axial direction on the outer peripheral surface of the first rod portion 11 of the advance / retreat rod 10, and is orthogonal to the axial direction of the advance / retreat rod 10 provided in the bearing cylinder 3. The screw hole 73 is formed, and includes a first screw 74 and a second screw 75 screwed into the screw hole 73.

The key groove 71 is formed in a trapezoidal cross-sectional shape in which the groove width is gradually narrowed from the outer peripheral surface toward the inside, the groove width (maximum groove width at the opening position) is 1.8 mm, and the angle formed by both side walls is 15 Formed at °.
The first screw 74 has a screw portion 74A that is screwed into the screw hole 73, and a key 74B that is integrally formed at the tip of the screw portion 74A and that is slidably engaged with the key groove 71. The key 74B is formed in a truncated cone shape, and the diameter of the key groove 71 at the outer peripheral surface position (the maximum groove width position of the key groove 71) is 1.8 mm.
The second screw 75 includes a screw portion 75 </ b> A that is screwed into the screw hole 73.

<Action>
In measurement, for example, when the thimble 43 or the ratchet knob 46 is rotated, the spindle 40 is displaced in the axial direction while rotating. Then, the rotation of the spindle 40 and the movement in the axial direction are transmitted to the advance / retreat rod 10. At this time, the advancing / retreating rod 10 is restricted by the linear guide mechanism 70 and is only allowed to move in the axial direction, and is thus moved in the axial direction together with the spindle 40.
While moving the advancing / retracting rod 10 in the axial direction, the object to be measured is sandwiched between the measuring claws 2 and 13, and the display value of the digital display 21 at this time is read. Alternatively, if the amount of displacement of the advance / retreat rod 10 is read from the main scale formed on the outer peripheral surface of the outer sleeve 35 and the vernier scale 47 formed along the outer periphery of the thimble 43, the dimensions of the object to be measured, etc. Can be measured.

<Effect of embodiment>
(1) A linear guide mechanism 70 includes a key groove 71 having a trapezoidal cross section formed on the outer peripheral surface of the advance / retreat rod 10 along the axial direction, and a frustoconical key that is slidably engaged with the key groove 71. 74B, it is possible to reduce the occurrence of play of the measuring claw as compared with the conventional structure.
(2) In particular, since the angle formed by the side walls on both sides of the key groove 71 is 15 °, compared to the conventional V groove (V groove angle is 60 °), the direction in which the key 74B is floated from the V groove 71 Since the force is also small, it is possible to reduce the occurrence of play on the measuring claw.

(3) Since the angle formed by the side walls on both sides of the key groove 71 is 15 °, when the key groove 71 is processed, the tolerance of the depth dimension of the key groove 71 can be increased compared to the conventional V groove processing.
In the case of the conventional V-groove 101, as shown in FIG. 4A, the V-groove angle is 60 ° and the maximum groove width is 0.8 mm. One side width of 101 changes A. Here, since A = B × tan 30 °, for example, when B = 0.01 mm, A = 0.006 mm.
In the present embodiment, as shown in FIG. 4B, the angle formed by the side walls of the key groove 71 is 15 °, and the maximum groove width is 1.8 mm. Here, if the one-side width change amount of the key groove 71 is 0.006 mm which is the same as that in FIG. 4A, B = A / tan 7.5 ° = 0.045 mm. Therefore,
In this embodiment, the tolerance of the depth dimension of the key groove 71 is 4.5 times the processing tolerance of the conventional V groove (under the same amount of change in one side width, the conventional V groove has B = 0.01 mm). The keyway of the present embodiment can be improved to B = 0.045 mm).

(4) Since the maximum groove width dimension of the key groove 71 and the diameter dimension of the key 74B at the maximum groove width position are 1.8 mm, the conventional V groove (V groove angle is 60 °). In comparison, the cross-sectional area can be increased, and therefore the strength can be increased.
(5) Since a screw hole 73 orthogonal to the axial direction of the advance / retreat rod 10 is formed in the bearing cylinder 3, a first screw 74 having a key 74B at the tip is screwed into the screw hole 73. By screwing the first screw 74, the degree to which the key 74B is fitted into the key groove 71 can be adjusted, and the fitting can be performed with an appropriate sliding resistance.
Further, since the second screw 75 is screwed into the screw hole 73 in contact with the rear end of the first screw 74, that is, since the two screws are screwed in series, the screw is loosened. Can also be reduced.

<Modification>
The present invention is not limited to the configuration of the embodiment described above, and includes the following examples.
In the above-described embodiment, an example in which the present invention is applied to a caliper type micrometer for outside measurement has been described. However, the present invention can also be applied to a caliper type micrometer for measuring inside such as a hole diameter and a groove width. In this case, a contactor that contacts the object to be measured may be provided outside the measurement claws 2 and 13.

  In the above-described embodiment, the spindle 40, the thimble 43 provided integrally with the spindle 40, and the like are included, and the advance / retreat mechanism 48 is configured to advance and retract the advance / retreat rod 10 in the axial direction as the spindle 40 is screwed. However, the advance / retreat mechanism 48 is not limited to this structure. In short, any other structure may be used as long as the advance / retreat rod 10 can be moved back and forth in the axial direction by a small amount.

  The form of the encoder 60 is not limited to the rotary encoder comprising the fixed plate 63 and the rotating plate 64 described in the above embodiment, but a cylindrical encoder having a coaxial cylindrical structure (for example, Japanese Patent Application No. 6-330689). Reference). 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 caliper type micrometer for measuring an outer dimension and an inner dimension.

The front view which notched one part which shows one Embodiment of the caliper type micrometer concerning this invention. The enlarged view which shows the principal part of embodiment same as the above. III-III sectional view taken on the line of FIG. The figure for demonstrating the point on which the trapezoid-shaped keyway in embodiment same as the above is advantageous on a process with respect to V groove. The perspective view which shows a common caliper type micrometer. The figure which shows the conventional linear guide mechanism. The figure which shows the conventional linear guide mechanism.

Explanation of symbols

1. Body frame (main body)
DESCRIPTION OF SYMBOLS 2,13 ... Measuring claw 10 ... Advance / retreat rod 40 ... Spindle 43 ... Thimble 48 ... Advance / retreat mechanism 70 ... Linear guide mechanism 71 ... Key groove 73 ... Screw hole 74 ... 1st screw 74B ... Key 75 ... 2nd screw

Claims (4)

A main body, an advancing / retracting rod provided on the main body through a linear guide mechanism so as not to be rotatable and capable of moving back and forth in the axial direction; A pair of measuring claws provided at right angles to each other, a spindle screwed into the main body and a thimble provided integrally with the spindle, and advancing and retreating the advancing and retracting rod in the axial direction as the spindle is screwed. Caliper type micrometer equipped with a mechanism,
The linear guide mechanism includes a key groove having a trapezoidal cross section formed in the outer peripheral surface of the forward / backward rod along the axial direction and having a groove width that gradually decreases from the outer peripheral surface toward the inside, and the key groove provided in the main body. And a frustoconical key that slidably engages with ,
A caliper-type micrometer characterized in that an angle formed by both side walls of the key groove is in a range of 7 ° to 30 ° . The caliper type micrometer according to claim 1 , wherein the key groove has a maximum groove width and a diameter of the key at a position of the maximum groove width of 1.2 to 2.4 mm. Caliper type micrometer. 3. The caliper type micrometer according to claim 1 , wherein a screw hole perpendicular to an axial direction of the advance / retreat rod is formed in the main body, and the first key having the key at the tip is formed in the screw hole. A caliper type micrometer characterized by screws being screwed together. The caliper type micrometer according to claim 3 , wherein a second screw is screwed into the screw hole in contact with a rear end of the first screw.

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