JP5438924B2 - Inner diameter measuring device - Google Patents

Description

  The present invention relates to an inner diameter measuring device that measures the inner diameter of a cylindrical hole such as a machining hole.

  Conventionally, a measuring apparatus for measuring the inner diameter of a hole formed in a cylindrical shape has been publicly known.

  The measuring device measures the inner diameter of the hole by inserting a guide member formed in a cylindrical shape and having a measuring element attached thereto into contact with the inner wall of the hole.

However, since the size of the guide member is fixed, when the size of the guide member does not match the inner diameter of the hole (when the probe cannot be brought into contact with the inner wall of the hole), the guide member is replaced or measured. It is necessary to replace the entire head (guide member, member that supports the guide member, etc.) to adapt the size of the guide member to the inner diameter of the object to be measured.
Therefore, when the inner diameter of the hole to be measured next is different from the inner diameter of the hole that has been measured up to now, it is necessary to replace the guide member and the measuring head before measuring the next hole. It was complicated and the work efficiency was reduced.

  As a technique for solving the above problem, there is an inner diameter measuring device described in Patent Document 1.

  The inner diameter measuring instrument described in Patent Document 1 is an inner diameter in which a head provided in a measuring instrument main body is inserted into a workpiece, and a measuring element protruding laterally from the head is brought into contact with the inner wall surface of the workpiece to measure the inner diameter. In the measuring instrument, the peripheral wall of the head is constituted by a plurality of variable guides that are independently movable in the radial direction, and the corners of the base ends of the variable guides are arranged at the central part of the measuring instrument main body. A micrometer is provided in the main body, and the spindle extending from the micrometer is fixed at a position where the spindle moves along the center line of the measuring instrument main body, and a tapered taper pin tapered to the tip of the spindle is provided. The taper surface of the taper pin is in contact with the corner portion of each variable guide base end.

The inner diameter measuring device described in Patent Document 1 can be changed by arbitrarily changing the diameter of the head formed by each variable guide by operating a micrometer, and even a workpiece with a different inner diameter can be handled with a single inner diameter measuring device. It is something to try.
In addition, the diameter of the head is accurately adjusted by accurately knowing the protrusion amount of the spindle by a micrometer.

  Moreover, as a technique for solving the above problem, an inner diameter measuring device described in Patent Document 2 can be cited.

  The inner diameter measuring device described in Patent Document 2 has a conical portion at one end, a moving shaft that is movable in the axial direction, and a moving means that is connected to the other end of the moving shaft and moves the moving shaft in the axial direction. And a plurality of measurement arms arranged substantially parallel to the movement axis around the movement axis, and the measurement arm is rotatably supported at the base side and has a distal end portion of the movement axis. An inner diameter measuring means having a measuring element which is in sliding contact with the peripheral surface of the conical portion and projecting outwardly is provided at the distal end portion of the measuring arm, and the moving shaft is moved in the axial direction by the moving means. The distal ends of these measurement arms are configured to be expandable and contractible around the axis of the moving shaft.

  The inner diameter measuring device described in Patent Document 2 can measure the inner diameter of a predetermined range of holes with a single inner diameter measuring device, and has a measuring arm that matches the inner diameter every time the inner diameter of the object to be measured changes. Therefore, it is intended to improve work efficiency without having to replace it one by one.

However, in the inner diameter measuring device described in Patent Document 1, when the spindle is moved along the center line of the measuring device main body to change the diameter of the head formed by each of the variable guides, the taper pin and the taper pin are Friction (sliding friction) occurs between the variable guides in contact with each other. As a result, when the diameter of the head is changed many times due to the movement of the spindle, the lower one of the taper pin and each of the variable guides wears out. There is a problem that the measurement accuracy is lowered such that the results are different, and the reliability of the measurement results is impaired.
In addition, the inner diameter measuring device described in Patent Document 2 is configured such that when the moving shaft moves in the axial direction, the tip of the measuring arm expands and contracts around the axis of the moving shaft. Friction (sliding friction) occurs between the arm and the conical portion of the moving shaft that is in sliding contact with the measurement arm. As a result, when the moving shaft is moved in the axial direction and the tip portion of the measuring arm is expanded and contracted many times, the conical portion of the measuring arm and the moving shaft is worn with the lower wear strength. As a result, there is a problem that the measurement accuracy is lowered such that the measurement result is different from that when not worn, and the reliability of the measurement result is impaired.
JP 2005-106695 A Japanese Patent Application Laid-Open No. 64-68601

  In view of the circumstances as described above, an object of the present invention is to provide an inner diameter measuring device having excellent measurement result reliability.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

An inner diameter measuring device according to a first aspect of the present invention includes a main body, a moving shaft supported by the main body so as to be movable back and forth in the axial direction, and an outer peripheral surface formed in a taper shape in the axial direction of the moving shaft. A tapered cone provided on the shaft; a variable guide that is rotatably supported by the main body on the base side thereof ; and that is disposed along the moving shaft; and is attached to a distal end side of the variable guide, and the variable guide A measuring element that rotates integrally with the measuring element, the variable guide is inserted into the hole, the measuring element is brought into contact with the inner wall of the hole, and the amount of change in the protruding amount of the measuring element is determined by the measuring element. the Rukoto be measured at the proximal end side, it is capable of measuring the inner diameter of the hole, the inner diameter of the distal end portion of the variable guide the forward and backward movement of the movable shaft is rotated in the direction toward and away from the said axis of movement A measuring device comprising the variable guide Optionally with the rotatably supported, comprising a bearing in contact with the outer peripheral surface of the tapered cone, and a bearing member supporting the moving shaft at both sides of the tapered cone with respect to the axial direction.

  The present invention has an effect that the reliability of the measurement result is excellent.

Below, the internal diameter measuring apparatus 10 which is one Embodiment of the internal diameter measuring apparatus which concerns on this invention is demonstrated.
The inner diameter measuring device 10 is a measuring device for measuring the inner diameter of a cylindrical hole such as a machining hole formed in a workpiece.
As shown in FIG. 1, the inner diameter measuring device 10 includes a main body 100, a moving shaft 200, a variable guide 300, and a displacement detector 400.

  The main body 100 is a member that forms the main structure of the inner diameter measuring device 10 and supports the moving shaft 200 and the variable guide 300.

The moving shaft 200 is formed in a rod shape.
The main body 100 includes bearings 110 and 110, and the moving shaft 200 is supported by the main body 100 via the bearings 110 and 110 so as to be able to advance and retreat in the axial direction of the moving shaft 200 in the middle.
The main body 100 is provided with a feed unit 500, and one end of the moving shaft 200 is connected to the feed unit 500.
The feed unit 500 includes an air cylinder 510, and the moving shaft 200 moves forward and backward in the axial direction using the air cylinder 510 as power.

  Although the air cylinder 510 is used in the feed unit 500, a motor-driven ball screw, a linear solenoid, or the like may be used instead of the air cylinder 510.

A tapered cone 210 is provided on the other end side of the moving shaft 200, and an outer peripheral surface 211 of the tapered cone 210 is formed in a tapered shape.
The tapered cone 210 is disposed at a position where the moving shaft 200 becomes an axis of symmetry, and the outer peripheral surface 211 formed in a tapered shape tapers toward the other end of the moving shaft 200. As a result, the outer peripheral surface 211 of the tapered cone 210 is inclined in the axial direction of the moving shaft 200.

  The variable guide 300 includes a shaft portion 310, a mounting portion 320, and a contact portion 330.

The shaft portion 310 is formed in a rod shape and is disposed along the movement axis 200 (in parallel with the movement axis 200 while providing an appropriate space between the movement axis 200).
One end of the shaft portion 310 is provided near the middle portion of the moving shaft 200, and the other end of the shaft portion 310 is provided near the other end side of the moving shaft 200.

A mounting portion 320 is integrally attached to one end of the shaft portion 310.
The attachment portion 320 is rotatably attached to the main body 100 by a pin 321, and the attachment portion 320 and the shaft portion 310 are integrated and in a predetermined direction (the other end of the shaft portion 310 is close to or moves to the moving shaft 200. It rotates about the pin 321 in the direction away from the shaft 200. Further, when the attachment portion 320 and the shaft portion 310 are integrally rotated, the shaft core of the shaft portion 310 and the shaft core of the moving shaft 200 are on the same plane.
The main body 100 includes a support portion 120 in the middle thereof, and the support portion 120 and the attachment portion 320 are connected by a guide return spring 130 that is an elastic member. In other words, the variable guide 300 is connected to the support portion 120 by the guide return spring 130 on the base side.
Thereby, the variable guide 300 is biased toward a predetermined direction (a direction in which the other end of the shaft portion 310 is close to the moving shaft 200).

As shown in FIG. 2, the contact portion 330 is integrally attached to the other end side of the shaft portion 310 with a screw 331, and the attachment portion 320, the shaft portion 310, and the contact portion 330 are integrally attached around the pin 321. Rotate.
The contact part 330 protrudes toward the moving shaft 200 side (taper cone 210 side).
The contact portion 330 is provided with a support shaft 340 and a ball bearing 350.
The support shaft 340 is a rod-shaped member and is attached to the contact portion 330 with a screw 341.
A support shaft 340 is inserted into the inner ring of the ball bearing 350, and the ball bearing 350 is rotatably supported by the support shaft 340.
In the support shaft 340 and the ball bearing 350, the outer ring of the ball bearing 350 is in contact with the outer peripheral surface 211 of the tapered cone 210, and the outer ring of the ball bearing 350 is on the outer peripheral surface 211 of the tapered cone 210 in the axial direction of the moving shaft 200. It is arranged at a position where it can roll.
That is, the variable guide 300 is in contact with the outer peripheral surface 211 of the tapered cone 210 via the ball bearing 350.

  The variable guide 300 is urged by a guide return spring 130 in a predetermined direction (a direction in which the other end of the shaft portion 310 is close to the moving shaft 200), so that the outer ring of the ball bearing 350 is the outer periphery of the tapered cone 210. The posture in contact with the surface 211 is maintained.

As shown in FIG. 1, the displacement detector 400 includes a measuring element 410 and a differential transformer 420.
The measuring element 410 is formed in a hemispherical shape and is integrally attached to the variable guide 300.
The measuring element 410 is disposed on the other end side of the shaft portion 310 of the variable guide 300 and slightly protrudes toward the counter moving shaft 200 side (anti taper cone 210 side).
The measuring element 410 is connected to a differential transformer 420, and the differential transformer 420 is connected to a control device (not shown).
When the probe 410 comes into contact with the inner wall of the hole, the amount of change in the protruding amount of the probe 410 is converted into an electric quantity by the differential transformer 420. As a result, the control device receives a signal from the differential transformer 420. Then, the inner diameter of this hole is calculated.

  The inner diameter measuring device 10 is provided with three other parts having the same configuration as the variable guide 300 and the displacement detector 400. The variable guides 300, 300, 300, and 300 and the displacement detectors 400, 400, 400, and 400 are They are arranged at equal intervals around the movement axis 200 (at positions where the movement axis 200 becomes a symmetrical axis).

  In the present invention, the number of variable guides and displacement detectors provided in the inner diameter measuring device is not particularly limited, and a plurality of variable guides and displacement detectors may be provided.

  Hereinafter, a case where the inner diameter of the hole is measured using the inner diameter measuring apparatus 10 will be described.

First, the operator or the like sets a reference inner diameter D ₀ in the inner diameter measuring apparatus 10.
The reference inner diameter D ₀ is set to a value slightly larger than the inner diameter of the hole desired by the operator as a measurement result (measurement value).

Specifically, the reference inner diameter D ₀ is set as follows.
When an operator or the like drives the air cylinder 510 of the feed unit 500, the moving shaft 200 moves back and forth in the axial direction.
As a result, the outer rings of the ball bearings 350, 350, 350, and 350 that are in contact with the tapered cone 210 of the moving shaft 200 roll on the outer peripheral surface 211 of the tapered cone 210 in the axial direction of the moving shaft 200.
At this time, since the outer peripheral surface 211 of the tapered cone 210 is inclined in the axial direction of the moving shaft 200, the variable guides 300, 300, 300, and 300 rotate around the pins 321, 321, 321, and 321, The other ends of the shaft portions 310, 310, 310, and 310 of the variable guides 300, 300, 300, and 300 are close to the moving shaft 200 or separated from the moving shaft 200.
That is, the direction in which the distal ends of the variable guides 300, 300, 300, and 300 are moved closer to and away from the movement shaft 200 around the pins 321, 321, 321, and 321 by the movement of the movement shaft 200 in the axial direction. To turn.
As described above, the variable guides 300, 300, 300, and 300 are rotated, whereby the axis of the moving shaft 200 and the measuring elements 410, 410, 410, and 410 attached to the shaft portions 310, 310, 310, and 310 are provided. (More strictly speaking, the distance from the outermost contour of the measuring element 410) becomes smaller or larger. Thereby, the measurement range by the inner diameter measuring device 10 is changed.
As described above, the operator or the like determines the position of the moving shaft 200 in the axial direction by driving the air cylinder 510 of the feed unit 500, and sets the distance from the outermost contour of the probe 410, that is, the inner diameter measuring device 10. The reference inner diameter D ₀ is set.

Next, the inner diameter measuring device 10 in which the reference inner diameter D ₀ is set is inserted into the hole to be measured.
Specifically, the other end side (variable guides 300, 300, 300, 300) of the moving shaft 200 is inserted into this hole. At this time, the other end side of the moving shaft 200 is inserted at a position where the core of the inner diameter of the hole coincides with the axis of the moving shaft 200. As a result, the measuring elements 410, 410, 410, and 410 come into contact with the inner wall of the hole, and the protruding amount of the measuring element 410 changes so as to conform to the shape of the inner wall of the hole. At this time, the amount of change in the protruding amount of the probe 410 is converted into an electric quantity by the differential transformer 420, and the control device receives a signal from the differential transformer 420 and calculates the inner diameter of the hole. Specifically, the control device subtracts the amount of change in the protruding amount of the measuring element 410 (the amount by which the measuring element 410 is contracted) from the reference inner diameter D ₀ set as described above, thereby reducing the inner diameter of the hole. calculate.

  As described above, the inner diameter of the hole is measured by the inner diameter measuring device 10.

As described above, when the reference inner diameter D ₀ is set by the inner diameter measuring apparatus 10, the moving shaft 200 is moved forward and backward by the feed unit 500. At this time, the outer ring 211 of the ball bearings 350, 350, 350, 350 rolls on the outer peripheral surface 211 of the tapered cone 210, and rolling friction occurs between the tapered cone 210 and the ball bearings 350, 350, 350, 350. Since the friction is smaller than when the variable guide slides on the outer peripheral surface of the taper cone and the sliding friction is generated, the variable guide 300/300/300/300 (ball bearing 350/350/350/350) and the taper cone 210 is less likely to wear. Thus, even if the moving shaft 200 is moved back and forth many times to reset the reference inner diameter D ₀ and the inner diameter measuring device 10 is used for a long period of time, the variable guides 300, 300, 300, 300 and the tapered cone 210 are Due to wear, it is possible to prevent the measurement result by the inner diameter measuring device 10 when measured under the same conditions from being significantly different between the initial measurement and the one used for a long time, and a stable measurement result can be obtained. Excellent result reliability.

As shown in FIG. 3, the line 600 includes an inner diameter measuring device (conventional one) in which the reference inner diameter D ₀ is changed when the movable shaft moves forward and backward and the variable guide slides on the outer peripheral surface of the tapered cone. An experiment was conducted to measure the inner diameter of a certain size while re-setting the reference inner diameter D ₀ using an inner diameter measuring device), and the relationship between the number of measurements and the measured value at this time was shown. Is.
The line 700 uses the inner diameter measuring device 10 and performs an experiment to measure the inner diameter of a certain size while performing the work of resetting the reference inner diameter D _0. This shows the relationship.
According to the line 600 and the line 700, the inner diameter measuring apparatus 10 is more remarkably different from the initial measurement, and the measurement result is more stable than the conventional inner diameter measuring apparatus, even if the number of measurements increases. Recognize. In particular, when the conventional inner diameter measuring apparatus is used repeatedly for a long time by resetting the reference inner diameter D ₀ , the variable guide closes (moves) compared to the initial measurement due to wear of the variable guide and the tapered cone. The measurement value becomes larger than the initial measurement.

The inner diameter measuring device 10, when changing the internal diameter D ₀ of the worker or the like as a reference, the variable guide 300, 300, 300, 300, etc. replacement only of the variable guide 300, 300, 300, 300 etc. It is not necessary to prepare, and the movable guide 200 can be moved forward and backward in the axial direction to rotate the variable guides 300, 300, 300, 300. Therefore, the inner diameter of the hole can be measured with an easy procedure.

Further, the guide member size is fixed (inner diameter D ₀ as a reference is fixed) internal diameter measurement device, the amount of projection of the gauge to reduce the guide diameter to cover a wide measuring range In general, if the diameter difference between the guide diameter of the inner diameter measuring device and the inner diameter of the hole to be measured increases, it is difficult to draw the core of the inner diameter of the hole to be measured by the inner diameter measuring device. It is known that measurement errors are likely to occur.
The inner diameter measuring device 10 can change the reference inner diameter D ₀ by moving the movable shaft 200 forward and backward in the axial direction and rotating the variable guides 300, 300, 300, 300, so that the guide diameter and the hole to be measured are changed. The difference in diameter from the inner diameter can be reduced. Thereby, the inner diameter measuring device 10 can easily draw the core of the inner diameter of the hole to be measured, and can reduce the measurement error.

The guide size is fixed member (inner diameter D ₀ as a reference is fixed) internal diameter measurement device is to increase the amount of projection of the measuring element in order to cover a wide measuring range, the measuring element is Although it is easy to contact the inner walls of various holes having different inner diameters, it is generally known that the measurement accuracy is sacrificed as the protruding amount of the probe increases.
The inner diameter measuring apparatus 10 can change the reference inner diameter D ₀ by rotating the variable guides 300, 300, 300, and 300 by moving the moving shaft 200 forward and backward in the axial direction. Even if the protrusion amount of 410 is reduced, the probe 410, 410, 410, 410 can be adjusted so as to contact the inner wall of the hole to be measured, and the inner diameter of the hole can be measured with high accuracy.

The schematic block diagram which shows one Embodiment of the internal diameter measuring apparatus which concerns on this invention. The partially expanded view of FIG. The relationship between the number of measurements and the measured value when measuring an inner diameter of a certain size under a predetermined condition using a conventional inner diameter assumption apparatus, and the conventional inner diameter assumption apparatus using the inner diameter measurement apparatus according to the present invention. The figure which shows the relationship between the frequency | count of a measurement when measured on the conditions similar to the time of and a measured value.

DESCRIPTION OF SYMBOLS 10 Inner diameter measuring apparatus 100 Main body 200 Moving shaft 210 Tapered cone 300 Variable guide 350 Ball bearing 410 Measuring element

Claims (1)

The body,
A moving shaft supported by the main body so as to be movable back and forth in the axial direction;
An outer peripheral surface formed in a taper shape in the axial direction of the moving shaft, and a tapered cone provided on the moving shaft;
A variable guide that is rotatably supported by the main body on the base side and is disposed along the movement axis;
A measuring element attached to the distal end side of the variable guide and rotated integrally with the variable guide;
Comprising
Inserting the variable guide hole, the measuring element into contact with the inner wall of the hole, by Rukoto to measure the amount of change in the amount of projection of the measuring element at the proximal end side of the gauge head, the inner diameter of the hole Is measurable,
An inner diameter measuring device in which the distal end portion of the variable guide is rotated in the direction of approaching and moving away from the moving shaft by the forward and backward movement of the moving shaft,
A bearing that is rotatably supported by the variable guide and that contacts the outer peripheral surface of the tapered cone, and a bearing member that supports the moving shaft on both sides of the tapered cone with respect to the axial direction. Inner diameter measuring device.

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