JP2005300319A - Measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive measuring instrument of simple structure capable of highly precisely measuring. <P>SOLUTION: A spindle 4 is supported movably axial-directionally onto a main body case 1 via a bearing 3, and a displacement detector 5 is provided to detect an axial-directional displacement amount of the spindle 4. The displacement detector 5 includes a scale 5A fixed onto the main body case along a moving direction in the spindle 4, and a detection head 5B fixed to the spindle 4 opposedly to the scale, and is provided with a coil spring 11 for pressing the spindle 4 to a direction substantially orthogonal to the moving direction thereof to energizing the spindle 4 to one side of the bearing 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a measuring instrument. More specifically, the present invention relates to a measuring instrument provided with a displacement detector that supports a spindle movably in the axial direction of the spindle via a bearing and detects the amount of axial displacement of the spindle.

  A configuration in which the spindle is movably supported in the axial direction of the main body case via a bearing and a displacement detector for detecting the amount of axial displacement of the spindle is arranged along the spindle moving direction is inexpensive and saves. Many are used for space reasons.

  For example, in the indicator shown in FIG. 3, the spindle 4 is pierced and supported in the axial direction through the bearings 2 and 3 on the upper wall 1A and the bottom wall 1B of the main body case 1 and the displacement detector 5 is configured. A structure is employed in which a scale 5A is arranged along the moving direction of the spindle 4 and a detection head 5B facing the scale 5A with a predetermined clearance is attached to the spindle 4 via an attachment piece 6. A coil spring 7 for urging the spindle 4 downward in FIG. 3 is stretched between the mounting piece 6 and the bottom wall 1B of the main body case 1. A locking pin 8 is projected from the mounting piece 6. The rotation prevention pin 8 is slidably engaged with the guide groove 1 </ b> C formed in the main body case 1, so that the spindle 4 is prevented from rotating.

  However, in this structure, an error occurs due to a backlash in a lateral direction due to a clearance between the spindle 4 and the bearings 2 and 3 that support the spindle 4, that is, a backlash in a direction perpendicular to the moving direction of the spindle 4. For example, when the spindle 4 is inclined with respect to the bearings 2 and 3 due to the backlash between the spindle 4 and the bearings 2 and 3, the relative posture between the detection head 5B and the scale 5A changes. Further, when the spindle 4 is tilted in the direction orthogonal to the paper surface of FIG. 4, the clearance between the detection head 5B and the scale 5A changes, which causes problems such as errors and reduction in repeatability.

  For this reason, in a measuring instrument having a resolution of 1 μm or less, an expensive bearing such as a bearing is adopted as the spindle support (bearings 2 and 3). For example, a structure has been adopted in which a spindle is movably supported on a main body through a support structure in which a plurality of stroke bearings are arranged in series (see Patent Document 1).

JP-A-11-37746

  In the conventional spindle support structure, the spindle is movably supported on the main body via a stroke bearing, which is expensive, and a long stroke measuring instrument can be used because a plurality of stroke bearings are arranged in series. However, there is a problem that only a large storage space is required.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a measuring instrument that can solve the conventional problems and can realize high-precision measurement with an inexpensive and simple structure without increasing the size.

  The measuring device of the present invention is a measuring device provided with a displacement detector for detecting the amount of displacement of the spindle in the axial direction while the spindle is supported by the main body via a bearing so as to be movable in the axial direction. The displacement detector includes a scale fixed to the main body along the moving direction of the spindle, and a detection head fixed to the spindle opposite to the scale and moving the spindle. An urging means for urging the spindle toward one side of the bearing by pressing in a direction substantially orthogonal to the direction is provided.

  According to this configuration, in the measuring instrument in which the spindle is supported by the main body via the bearing so as to be movable in the axial direction, the spindle is pressed in a direction substantially perpendicular to the moving direction, and the spindle is moved to one side of the bearing. Since the urging means for urging is provided, the spindle is always moved in the axial direction in contact with one side of the bearing. Accordingly, since the spindle moves while the clearance between the spindle and the bearing is always kept constant, the repeatability can be maintained and high-precision measurement can be achieved. Moreover, structurally, it is only necessary to provide a biasing means for pressing the spindle in a direction substantially perpendicular to the moving direction thereof, so that it is an inexpensive and simple structure, and does not increase in size and is highly accurate. Measurement can be realized.

In the measuring instrument of the present invention, the direction in which the urging means presses the spindle is substantially perpendicular to the moving direction of the spindle and is substantially parallel to the detection surface of the scale. preferable.
According to this configuration, the direction in which the urging means presses the spindle is substantially orthogonal to the moving direction of the spindle and is substantially parallel to the detection surface of the scale. The head is moved in a direction substantially parallel to the detection surface of the scale. If the detection head moves in a direction substantially parallel to the detection surface of the scale, the clearance between the scale and the detection head is less likely to fluctuate. In general, when the clearance between the scale and the detection head varies, there is a problem that miscounting occurs in a signal processing circuit and the like, and stable high-accuracy measurement cannot be realized. Since there is little fluctuation, high-precision measurement can be guaranteed.

In the measuring instrument of the present invention, it is preferable that the biasing means is provided between the main body and the spindle in the vicinity of the bearing.
According to this configuration, since the urging means is provided in the vicinity of the bearing, that is, in the vicinity of the bearing, the spindle is pressed in a direction substantially orthogonal to the moving direction of the spindle, so the spindle against the bearing. Can be prevented from tilting. Accordingly, since the spindle is in contact with the entire length of one side surface of the bearing, the relative posture change between the scale and the detection head does not occur, and uneven wear of the bearing can be reduced.

In the measuring instrument of the present invention, it is preferable that the biasing means is a torsion coil spring having one end locked to the main body and the other end biasing the spindle.
According to this configuration, since the biasing means is constituted by the torsion coil spring, it can be configured at low cost and can be easily incorporated between the main body and the spindle. That is, it is only necessary to lock one end of the torsion coil spring to the main body and bias the spindle at the other end.

In the measuring instrument of the present invention, it is preferable that a pulley having a groove on the outer periphery that matches the shape of the axial circumferential surface of the spindle is rotatably supported at the other end of the torsion coil spring.
According to this configuration, the pulley having a groove that matches the shape of the axial circumferential surface of the spindle is rotatably supported at the other end of the torsion coil spring. Therefore, when the spindle moves in the axial direction, the pulley is rotated. Therefore, the wear generated between the pulley and the spindle can be suppressed to an extremely small amount. Therefore, a long life can be expected.

In the measuring instrument according to the present invention, the biasing means may be pivotable on the main body and arranged substantially orthogonal to the axial direction of the spindle, and parallel to the support shaft and to the support shaft. An eccentric pin having an eccentric shaft at an eccentric position, and a pulley having a groove that is rotatably supported by the eccentric shaft of the eccentric pin and has a groove that matches the shape of the spindle in the axial direction on the outer periphery. It is preferable to be configured.
According to this configuration, when the support shaft of the eccentric pin is rotated, the pulley supported rotatably on the eccentric shaft of the eccentric pin approaches or is separated from the spindle. Therefore, when the eccentric pin is rotated and adjusted, the spindle is pressed in a direction substantially orthogonal to the axial direction and is in contact with one side of the bearing. Accuracy measurement can be achieved. In addition, since an eccentric pin may be used structurally, high-precision measurement can be realized with an inexpensive and simple structure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Embodiment>
FIG. 1 shows an indicator that is a measuring instrument. In the description of the present embodiment, the same constituent elements as those shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted or simplified.
The indicator of this embodiment includes a vertically long box-shaped main body case 1 as a main body. In the main body case 1, a spindle 4 is supported so as to be movable in the axial direction, and a displacement detector 5 for detecting the amount of displacement of the spindle 4 in the axial direction is provided.

The main body case 1 has the same configuration as shown in FIG.
Similarly to the structure shown in FIG. 3, the spindle 4 is also supported on the upper wall (not shown) and the bottom wall 1B of the main body case 1 via a bearing 3 (the bearing 2 is not shown) so as to be movable in the axial direction. In addition, a measuring element 4A that comes into contact with the object to be measured is provided at the lower end. The bearings 2 and 3 are made of metal bearing bushes, but bearings may be used.

  The displacement detector 5 includes a scale 5A fixed to the main body case 1 in the vicinity of the spindle 4 and along the moving direction of the spindle 4, and a spindle 5 via a mounting piece 6 that is disposed to face the scale 5A with a predetermined clearance. 4 and a detection head 5B fixed to 4. The detection method using the scale 5A and the detection head 5B may be any detection method such as a photoelectric method or a capacitance method.

In the present embodiment, an urging means 10 is further provided for urging the spindle 4 to one side of the bearings 2 and 3 by pressing the spindle 4 in a direction substantially orthogonal to the moving direction.
The biasing means 10 is constituted by a torsion coil spring 11. The torsion coil spring 11 is wound around a pin 12 projecting from the main body case 1 near the bearing 3 one or two times, and its one end 11A is locked to the bottom wall 1B of the main body case 1, and the other end 11B is It is in contact with the spindle 4 via the pulley 13.

Thereby, the spindle 4 is pressed in a direction substantially orthogonal to the moving direction, and is urged to one side (right side in FIG. 1) of the bearing 3. That is, the direction in which the spindle 4 is pressed by the torsion coil spring 11 is set to be substantially perpendicular to the moving direction of the spindle 4 and substantially parallel to the detection surface of the scale 5A.
The pulley 13 is rotatably supported on the other end 11B of the torsion coil spring 11, and has a groove on the outer periphery that matches the shape of the axial circumferential surface of the spindle 4, specifically, a groove 13A having a semicircular cross section. Is formed.

The operation of this embodiment will be described.
In measurement, the spindle 4 is lifted upward in FIG. 1 against the urging force of the spring 7, and then the object to be measured is placed directly under the spindle 4. After that, the spindle 4 is lowered by the urging force of the spring 7 and brought into contact with the object to be measured. Then, the displacement amount of the spindle 4 up to the position where the spindle 4 contacts the object to be measured is detected by the displacement detector 5 and digitally displayed on a display (not shown).

  At this time, since the spindle 4 is urged to the right in FIG. 1 by the torsion coil spring 11, the spindle 4 is always moved in the axial direction in contact with one side of the bearings 2 and 3 (right side in FIG. 1). The Accordingly, since the spindle 4 moves while the clearance between the spindle 4 and the bearing 3 is always kept constant, the repeatability can be maintained and high-precision measurement can be achieved.

According to this embodiment, the following effects can be expected.
(1) In an indicator in which the spindle 4 is supported by the main body case 1 via the bearings 2 and 3 so as to be movable in the axial direction, the spindle 4 is pressed by pushing the spindle 4 in a direction substantially orthogonal to the moving direction. Since the urging means 10 for urging on one side of the bearings 2 and 3 is provided, the spindle 4 is always moved in the axial direction in contact with one side of the bearings 2 and 3. Therefore, since the spindle 4 moves while the clearance between the spindle 4 and the bearings 2 and 3 is always kept constant, the repeatability can be maintained and high-precision measurement can be achieved.

(2) Structurally, since it is only necessary to provide the urging means 10 that presses the spindle 4 in a direction substantially orthogonal to the moving direction, high-accuracy measurement can be realized with an inexpensive and simple structure.

(3) The direction in which the urging means 10 presses the spindle 4 is substantially perpendicular to the moving direction of the spindle 4 and is substantially parallel to the detection surface of the scale 5A. The detected head 5B is moved in a direction substantially parallel to the detection surface of the scale 5A. When the detection head 5B moves in a direction substantially parallel to the detection surface of the scale 5A, the clearance between the scale 5A and the detection head 5B is less likely to fluctuate.

(4) Since the biasing means 10 is provided in the vicinity of the bearing 3, that is, in the vicinity of the bearing 3, the spindle 4 is pressed in a direction substantially orthogonal to the moving direction of the spindle 4. On the other hand, the tilt of the spindle 4 can be suppressed. Accordingly, since the spindle 4 is in contact with the entire length of one side surface of the bearing 3, the relative posture between the scale 5A and the detection head 5B does not change, and the bearings 2 and 3 are worn unevenly. Can also be reduced.

(5) Since the biasing means 10 is constituted by the torsion coil spring 11, it can be constructed at low cost and can be easily assembled between the main body case 1 and the spindle 4. That is, since one end 11A of the torsion coil spring 11 only needs to be locked to the main body case 1 and the spindle 4 is urged by the other end 11B, the assembly can be simplified.

(6) Since the pulley 13 having the groove 13A matching the axial circumferential shape of the spindle 4 is rotatably supported at the other end 11B of the torsion coil spring 11, when the spindle 4 moves in the axial direction, the pulley Since 13 is rotated, wear generated between the pulley 13 and the spindle 4 can be suppressed to an extremely small amount. Therefore, a long life can be expected.

<Modification>
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
In the above embodiment, the biasing means 10 is constituted by the torsion coil spring 11, but the invention is not limited to this, and other configurations may be used.

  For example, as shown in FIG. 2, the urging means 10 may include an eccentric pin 21 and a pulley 13. The eccentric pin 21 is rotatable with respect to the main body case 1 and arranged substantially orthogonal to the axial direction of the spindle 4, and is parallel to the support shaft 22 and with respect to the support shaft 22. An eccentric shaft 23 is provided at an eccentric position. The pulley 13 is rotatably supported by the eccentric shaft 23 of the eccentric pin 21 and has a groove 13A that matches the shape of the axial circumferential surface of the spindle on the outer periphery.

  In such a configuration, when the support shaft 22 of the eccentric pin 21 is rotated, the pulley 13 rotatably supported by the eccentric shaft 23 of the eccentric pin 21 approaches or is separated from the spindle 4. Therefore, when the eccentric pin 21 is rotated and adjusted, the spindle 4 is pressed in a direction substantially orthogonal to the axial direction and is in contact with one side of the bearings 2 and 3. Can be maintained, and highly accurate measurement can be achieved. In addition, since only the eccentric pin 21 is required in terms of configuration, high-precision measurement can be realized with an inexpensive and simple structure.

  In addition to the example shown in FIG. 2, a plate spring may be used to press the spindle 4 in a direction substantially perpendicular to the moving direction thereof to bias the spindle 4 to one side of the bearings 2 and 3. . Even in this case, if the low friction member is provided at the end of the leaf spring that contacts the spindle 4, the movement of the spindle 4 is not hindered.

In the above-described embodiment, the spindle 4 is supported on the upper wall 1A and the bottom wall 1B of the main body case 1 so as to be movable in the axial direction via the bearings 2 and 3. The structure which supports it may be sufficient.
The displacement detector 5 may be of any type such as a photoelectric type, a magnetic type, or a capacitance type. Similarly, the measurement result may be displayed on a display provided in the main body case 1 or may be displayed on another display device. That is, it does not ask about a display form.

  In addition to dial gauges and indicators, the present invention can be applied to all measuring instruments in which a spindle is supported by a main body via a bearing and linearly moves in the axial direction.

The figure which shows the indicator concerning embodiment of this invention. The figure which shows the indicator concerning other embodiment of this invention. The figure which shows the conventional indicator. The figure which shows the problem of the conventional indicator.

Explanation of symbols

1 ... Main unit case (main unit)
2, 3 ... Bearing 4 ... Spindle 5 ... Displacement detector 5A ... Scale 5B ... Detection head 10 ... Energizing means 11 ... Torsion coil spring 11A ... One end 11B ... Other end 13 ... Pulley 13A ... Groove 21 ... Eccentric pin 22 ... Support shaft 23 ... Eccentric shaft

Claims (6)

In a measuring instrument provided with a displacement detector for detecting the amount of displacement of the spindle in the axial direction while the spindle is supported by the main body via a bearing so as to be movable in the axial direction.
The displacement detector includes a scale fixed to the main body along the moving direction of the spindle, and a detection head facing the scale and fixed to the spindle.
A measuring instrument, comprising: an urging means for urging the spindle toward one side of the bearing by pressing the spindle in a direction substantially perpendicular to the moving direction thereof. The measuring instrument according to claim 1, wherein
The measuring instrument according to claim 1, wherein a direction in which the urging means presses the spindle is substantially perpendicular to a moving direction of the spindle and substantially parallel to a detection surface of the scale. The measuring instrument according to claim 1 or 2,
The urging means is provided between the main body and a spindle in the vicinity of the bearing. In the measuring device in any one of Claims 1-3,
The biasing means is a torsion coil spring having one end locked to the main body and the other end biasing the spindle. The measuring instrument according to claim 4, wherein
A measuring instrument, characterized in that a pulley having a groove matching the shape of the axial circumferential surface of the spindle is rotatably supported at the other end of the torsion coil spring. The measuring instrument according to claim 1, wherein
The biasing means is offset to a support shaft that is pivotable to the main body and substantially orthogonal to the axial direction of the spindle, and is parallel to the support shaft and eccentric to the support shaft. An eccentric pin having a core shaft, and a pulley having a groove that is rotatably supported by the eccentric shaft of the eccentric pin and has a groove that matches the shape of the axial surface of the spindle on the outer periphery. Measuring instrument.

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