JPS63131018A - Apparatus for measuring inner and outer diameters - Google Patents

Abstract

PURPOSE:To perform highly accurate measurement regardless of the material quality of an article to be measured even when the origin can not be established due to the movement of the movable contact element on a base line, by forming the shape of the contact element in a spherical or columnar form and using a master gauge. CONSTITUTION:An inner diameter, an outer diameter or the size of a diameter are selected by a keyboard 24. Next, the master gauge 31 fitted to this measuring condition is set and fixed contact elements 16A, 16B are respectively inserted in contact element insert holes 13A, 13B or 15A, 15B corresponding to the inner or outer diameter and abutted with the inner or outer peripheral surface of the gauge 31 together with a movable contact element 17. In parallel to this, the inner diameter D of the gauge 31, the distance L on the base line connecting the centers of the contact elements 16A, 16B and the diameter (d) of the contact elements are inputted and the diameter (d) is set to a positive or negative value corresponding to the inner or outer diameters by a CPU 23 and the value (a) calculated based on a=[{(D-d)}+ or -{(D-d)<2>-L<2>}<1/2>]/2 is preset to a counter 22 corresponding to the size of the measured diameter. Herein, an article to be measured is set in place of the gauge 31 and the diameter thereof is calculated according to a predetermined formula.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is capable of determining the inner diameter or outer diameter of a measured object based on the positional relationship of three contacts brought into contact with the inner or outer peripheral surface of the measured object. This invention relates to an inner and outer diameter measuring device for measuring.

[Background technology and its problems]

BACKGROUND ART Conventionally, an inner/outer diameter measuring device is known that measures the inner or outer diameter of the object by bringing three contacts into contact with the inner or outer circumferential surface of the object to be measured based on the positional relationship between the three points.

The present applicant has also previously proposed an inner/outer diameter measuring device described in Japanese Utility Model Application Publication No. 58-60204. As shown in FIG. 7, two fixed contacts 2A and 2B with needle-shaped tips are provided on the frame 1 in parallel with each other, and
A spindle 5 of a displacement detector 4 having a movable contact 3 at its tip is arranged on an axis that vertically bisects the base line connecting the tips of the two fixed contacts 2A and 2B, and the amount of displacement of this spindle 5 is set as a variable. This configuration is provided with an arithmetic circuit 6 for calculating the inner diameter or outer diameter of the object 7 to be measured.

During measurement, both fixed contacts 2A and 2B are connected to the object to be measured 7.
The movable contactor 3 is brought into contact with the object to be measured 7 by movement of the spindle 5. Then, after the amount of movement of the spindle 5, that is, the amount of displacement of the movable contact 3 is detected by the displacement detector 4, the arithmetic circuit 6
given to.

Now, if we calculate the distance between the base lines connecting the tips of the two fixed contacts 2A and 2B, and let a be the displacement of the movable contact 3 from the origin P where the base line and the axis intersect, then the inner diameter of the object 7 to be measured is Alternatively, the outer diameter D" can be calculated from the following equation. That is,.

In such an inner/outer diameter measuring instrument, the fixed contact 2A.

Since the tips of the contacts 2B and the movable contact 3 are both needle-shaped, if the material to be measured 7 is relatively soft, the tips of the contacts 2A, 2B, and 3 will dig into the object 7, resulting in measurement errors. There is a problem that causes

Moreover, since the fixed contacts 2A, 2B and the movable contact 3 are configured to abut against the inner circumferential surface or outer circumferential surface of the object to be measured 7 from the same direction, it is relatively easy to use when the object to be measured 7 has a large diameter. Although it is possible to measure the inner diameter or outer diameter of the object to be measured 7 with high precision, high precision measurement cannot be expected if the diameter is small. For example, when trying to measure the outer diameter of an object to be measured whose outer diameter is slightly larger than the distance of the baseline, both fixed contacts 2A and 2B will come into contact with the outer peripheral surface close to the central axis passing through the center of the object to be measured. , it is not possible to set the fixed contacts 2A and 2B in a stable state, resulting in a measurement error.

Therefore, in the case of an object to be measured whose diameter is relatively small, the eighth
A configuration as shown in the figure may also be considered.

In other words, if both fixed contacts 2A and 2B are configured to contact the object to be measured 7 from the opposite side of the movable contact 3 with the object to be measured 7 in between, there will be three contacts 2A.

Since the object to be measured 7 is automatically centered by 2B and 3, highly accurate measurement can be achieved.

However, with this configuration, it becomes difficult to establish the origin of the movable contactor 3. That is, in the configuration shown in FIG. 7, when the fixed contacts 2A, 2B and the movable contact 3 are located on the same plane, that is, the tip of the movable contact 3 is connected to the base connecting the tips of the fixed contacts 2A, 2B. When the displacement detector 4 is positioned on the line, the value of the displacement detector 4 should be zero cents, but if the configuration is as shown in FIG. As a result, the displacement detector 4 cannot be set to zero, resulting in the problem that the displacement 'FJa cannot be determined.

[Purpose of the invention]

Here, the object of the present invention is to
Another object of the present invention is to provide an inner/outer diameter measuring device that can measure the inner diameter or outer diameter of an object with high accuracy even when the origin cannot be established by moving the movable contact on the base line.

[Means and actions to solve the problem] Therefore,
In the present invention, first, by making the contact shape spherical or columnar with diameter d, measurement errors due to the material of the object to be measured are eliminated, and the origin can be established by moving the movable contact onto the base line. Even if this is not possible, the master gauge can be used to easily establish the origin of the movable contact.

Specifically, two fixed contacts are provided on a base, each having a diameter d and a distance L on a base line connecting their centers, and a fixed contact disposed on the base along an axis that perpendicularly bisects the base line. a movable contact with a diameter of d; a displacement detector that converts the displacement of the movable contact into an electrical signal; and a displacement detector that processes the signal from the displacement detector to determine the displacement of the movable contact. a counter that obtains a measurement value, a selection of whether the measurement item is the inner diameter or the outer diameter, and a first measurement mode in which the movable contact contacts the object to be measured from the opposite side to the fixed contact; a setting means for selecting whether it is a second measurement mode of contacting from the same side; a recording means for storing the measurement conditions set by the setting means; and measurement conditions stored in the storage means; Based on the diameter d and distance, and assuming that the amount of displacement of the movable contact from the origin where the base line and the axis intersect is X, the inner diameter or outer diameter D of the object to be measured with which the three contacts are in contact. calculation means for calculating ゛ according to a preset calculation formula, and the calculation means includes:
When establishing the origin using a master gauge whose inner diameter or outer diameter is known, among the measurement conditions stored in the storage means, when the measurement item is the inner diameter, the diameter d is set to a positive value, and when the measurement item is the outer diameter, the diameter d is set to a positive value. When the diameter d is a negative value, and the first measurement mode is selected, and the second measurement mode is selected, find a,
The present invention is characterized in that a function is added to preset this value a in the counter.

Therefore, the measurement principle of the present invention will be explained with reference to FIG.

First, there are two fixed contacts 16A each having a diameter d and a distance L on the base line connecting their centers.

16B and a movable contact 17 displaceable along an axis that perpendicularly bisects the base line and having a diameter d are brought into contact with the inner circumferential surface of a master gauge 31 having a known inner diameter, for example. let At this time, the origin P where the base line and the axis intersect
When the amount of displacement of the movable contactor 17 from .

Solving this equation (3) for a, we get becomes.

Here, it can be seen that there are two solutions for a. This is the second
As shown in the figure, the first measurement mode B, that is, the small diameter measurement mode, in which the movable contact 17 contacts the master gauge 31 from the side opposite to the fixed contacts 16A and 16B [FIG. 2(A)
In the case of B)), a + sign is used for the second measurement mode, that is, the large diameter measurement mode, in which the movable contact 17 contacts the master gauge 31 from the same side as the fixed contacts 16A and 16B [Fig. C) (D)], it is sufficient to take the - sign, respectively.

In addition, in equation (4), the diameter d of the contact is −ldl
It can be seen that if it is converted to a negative value, it can also be applied to outer diameter measurement.

As a result, the displacement fJa from the origin P to the current movable contact 17 is determined. After presetting this value a as the value of the counter that obtains the displacement amount of the movable contact 17, the diameter D An object to be measured is set, and the three contacts 16A, 16B, and 17 are brought into contact with the inner or outer peripheral surface of the object.

If the amount of displacement of the movable contactor 17 from the origin P at this time is defined as X, then the following holds true, similar to the above equation (3). This (5
) Solving the equation for D' yields z. Therefore, since the diameter d of the contact, the amount of displacement X of the movable contact 17 from the origin P, and the distance on the base line are all known, the inner diameter or outer diameter of the object to be measured can be determined from the above equation (6). I can do it.

〔Example〕

Hereinafter, one embodiment of the inner and outer diameter measuring device of the present invention will be described based on FIGS. 3 to 6.

FIG. 3 shows a plan view of the same device, and FIG. 4 shows a cross section taken along the line ■--■ in FIG. 3. In these figures, a groove 12 having a width of about 1/2 of the width of the base 11 is formed in the center of the upper surface of the substantially square base 11 in the front-rear direction. Inside the groove 12, there are a total of three pairs of contact insertion holes 13A and 13B, left and right pairs, which are equidistant from the center axis in the left and right direction.
~15A.

15B are provided at predetermined intervals in the front-rear direction. In addition, when the distance between the base line connecting the centers of the insertion holes 13A and 13B and the base line connecting the centers of the insertion holes 15A and 15B is expressed as follows, the insertion hole 14A.

The distance on the baseline connecting the centers of 14B is set to L2, which is shorter than Ll. Two fixed contacts 16A, 16B each having a spherical tip are replaceably and selectively inserted into any one of these pairs of contact insertion holes 13A, 13B to 15A, 15B.

Further, at a rear position within the groove 12, a movable contact 17 having a spherical tip is arranged along an axis that vertically bisects the base line connecting the centers of both rotating contacts 16A and 16B, that is, the contact insertion hole 13 of each set.
Base line connecting the centers of A, 13B to 15A, 15B (L+
, Lx) respectively vertically into two equal parts. The movable contactor 17 includes a displacement detection device 19 fixed to the base 11 via a mounting frame 18.
is attached to the tip of a spindle 20, and is displaced along the axis by movement of this spindle 20.

The displacement detection device 19 detects the amount of displacement of the spindle 20, calculates a from this amount of displacement and various measurement conditions set by the keyboard 24 as a setting means according to the calculation formula (4), and The inner diameter or outer diameter of the object to be measured is calculated according to the calculation formula (6), and this is displayed on the display 2.
Display digitally on 6.

FIG. 5 shows the configuration of the displacement detection device 19. Displacement detector 2
1 includes, for example, a main scale provided on the spindle 20, an index scale and a light emitter/receiver provided on the stationary member side of the displacement detection device 19 opposite thereto,
The amount of displacement of the spindle 20 is converted into an electrical signal. The electrical signal from the displacement detector 21 is converted into a pulse signal by a circuit (not shown) and then counted by the counter 22. The value of the counter 22 is taken into the CPU 23 as a calculation means.

The CPU 23 stores the measurement conditions, etc. input from the keyboard 24 in the memory 25, which is a storage means, and calculates the inner diameter or Find the outer diameter,
This is displayed digitally on the display 26. Here, the keyboard 24 allows selection of whether the measurement item is the inner diameter or the outer diameter, and the movable contact 17 is applied to the object to be measured or the master gauge 31 from the side opposite to the fixed contacts 15A, 16B. In addition to selecting the first measurement mode (small diameter measurement mode) in which they touch each other or the second measurement mode (large diameter measurement mode) in which they touch each other from the same side, the diameter d, distance I5, master gauge It is formed so that the inner diameter or outer diameter of 31 can be input.

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG.

First, the measurement item and measurement mode are selected using the keyboard 24. For example, when measuring a relatively small inner diameter, select the inner diameter and small diameter measurement modes. Then, these measurement conditions are stored in the memory 25. below,
The explanation will be made according to these measurement conditions.

Next, a master gauge 31 that meets these measurement conditions is
The three contacts 16A, 16B, and 17 are brought into contact with the inner peripheral surface of the master gauge 31, and the inner diameter of the master gauge 31 is input from the keyboard 24. Note that, before this, the fixed contacts 16A and 16B are inserted into the contact insertion holes 13A and 13B, and
The distance on the base line connecting the centers of the double-sided constant contacts 16A and 16B and the diameter d are input from the keyboard 24.

The CPU 23 records the inner diameter, etc. input from the keyboard 24 in the memory 25, and then determines whether the selected measurement item is the outer diameter. If the selection of the measurement item is the outer diameter, the diameter d is set to a negative value; if it is not the outer diameter, that is, if it is the inner diameter, the diameter d is set to a positive value, and then whether or not it is a small diameter measurement mode is determined. to judge.

If the selection of the measurement mode is the small diameter measurement mode, a is calculated using the calculation formula, and if the selection is the large diameter measurement mode, the calculation formula is used to calculate a, and this value a is preset in the counter 22.

Here, when an object to be measured is set in place of the master gauge 31 and the three contacts 16A, 16B, and 17 are brought into contact with the inner circumferential surface or outer circumferential surface of this object to be measured, the origin point P
Since the displacement Wkx from to the movable contact 17 is given to the CPU 23, the CPU 23 calculates the inner diameter or outer diameter D° of the object to be measured according to the calculation formula D'=d+x+-X, and displays it digitally on the display 26. do.

In this way, by sequentially setting the objects to be measured and repeating the above-described operations, it is possible to successively measure the inner diameter or outer diameter of the objects to be measured.

On the other hand, when measuring the inner diameter or outer diameter of a workpiece with a smaller diameter, the fixed contacts 16A and 16B are replaced from the contact insertion holes 13A and 13B to the contact insertion holes 14A and 14B, and fixed in this state. The contacts 16A, 16B and the movable contact 17 are brought into contact with the inner or outer peripheral surface of a master gauge that is compatible with them. Then, in this state, the displacement amount a of the movable contact 17 from the origin P2 is calculated by the process described above, and this (i a z ) is calculated by the counter 2.
2, then measure the inner diameter or outer diameter of the object to be measured. In this case, since the distance on the baseline is L2, this distance L! is input from the keyboard 24 and rewritten.

When measuring the inner diameter or outer diameter of an object to be measured with a large diameter, the fixed contacts 16Δ and 16B are replaced with the contact insertion holes 15A and 15B, and the fixed contacts 16 in this state are
A, 16B and the movable contact 17 are brought into contact with the inner peripheral surface or outer peripheral surface of a master gauge that fits them. Then, the displacement fla of the movable contact 17 from the origin P3 in this state is calculated by the process described above, and after presetting this value a in the counter 22, the inner diameter or outer diameter of the object to be measured is measured.

Therefore, in this embodiment, the double-sided constant contact 16A is used.

Since the movable contact 16B and the movable contact 17 have a spherical shape with a diameter d, these contacts 16A, 16B, and 17 will not dig into the object even if the object to be measured is made of a soft material. Or the outer diameter can always be measured with high precision.

In addition, since the origin of the movable contact can be established using the master gauge 31, both fixed contacts 16A and 16
Even if the movable contactor 17 cannot be moved to the base line connecting the centers of B to zero-set, the inner diameter or outer diameter of the object to be measured can be measured.

Moreover, three sets of contact insertion holes 13A, 13B-15A are provided along the axial direction in which the movable contact 17 is displaced.

15B, and the fixed contacts 16A and 16B are replaced in these pairs of contact insertion holes, so when the object to be measured has a relatively small diameter, both the fixed contacts 16A and 16B are replaced.
Since the movable contactor 17 can be brought into contact with the object to be measured from the opposite side, even objects to be measured with a relatively small diameter can be measured stably and with high precision. Furthermore, this eliminates the need to increase the possible displacement range, that is, the stroke, of the spindle 20 of the displacement detector 21, so the overall size and cost are reduced.

Moreover, regarding the distance L2 on the baseline connecting the centers of the contact insertion holes 14A and 14B, the distance L2 on the base line connecting the centers of the contact insertion holes 14A and 14B is
Since the distance L1 is set shorter than the distance L1 on the baseline connecting the centers of the BSs 15A and 15B, it is possible to measure the inner diameter or outer diameter of a smaller diameter object.

In addition, in implementation, each contactor 16A, 16B, 17
The shape is not limited to the spherical shape described in the above embodiment, but may be, for example, a columnar or cylindrical shape.

Further, in the above embodiment, the contact insertion hole 13A.

Three sets of 13B to 15A and 15B are provided along the axial direction,
These insertion holes 13A, 13B to 15Δ.

By replacing the fixed contacts 16A, 16B with 15B, the movable contact 17 can be moved relative to the fixed contact 16A, 16B in the axial direction.
Conversely, the displacement detection device 19 including the movable contact 17 may be configured to be movable along the axial direction.

Further, the displacement detector is not limited to the optical displacement detector 21 described in the above embodiment, but may be a magnetic type, a capacitance type, etc., which can detect the amount of displacement of the movable contact 17 as an electrical signal. Any item is fine.

[Effects of the Invention] As described above, according to the present invention, the inner diameter or outer diameter of the object can be determined regardless of the material of the object to be measured, and even if the origin cannot be established by moving the movable contact on the base line. It is possible to provide an inner and outer diameter measuring device that can measure diameters with high precision.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the principle of measuring the inner and outer diameters of the present invention.
Fig. 2 is a diagram showing a measurement mode, Fig. 3 is a plan view showing an embodiment of the present invention, Fig. 4 is a sectional view taken along the line IV-TV in Fig. 3,
Fig. 5 is a block diagram showing the displacement detection device, Fig. 6 is a flowchart showing the measurement processing procedure, Fig. 7 is a plan view showing the measurement principle using a conventional inner and outer diameter measuring instrument, and Fig. 8 is a diagram showing the measurement principle of a conventional measuring instrument. FIG. 3 is a diagram for explaining a problem. 11... Base, 16A, 16B... Fixed contact,
17... Movable contactor, 21... Displacement detector, 22...
...Counter, 23...CPU as calculation means, 2
4...Keyboard as a setting means, 25...Memory as a storage means, 31...Master gauge. Figure 1 Figure 2 CB) (A) CD)
(C) Figure 3 ■'' Figure 4 Figure 5 Figure 6

Claims (4)

[Claims] (1) Two fixed contacts provided on a base, each having a diameter d and a distance L on the base line connecting their centers, and two fixed contacts disposed on the base and movable along an axis that perpendicularly bisects the base line. a movable contact provided and having a diameter d; a displacement detector that converts the amount of displacement of the movable contact into an electrical signal; and a signal from the displacement detector is processed to obtain the amount of displacement of the movable contact. The counter, the selection of whether the measurement item is the inner diameter or the outer diameter, and the first measurement mode in which the movable contact contacts the object to be measured from the opposite side to the fixed contact or the same side. a setting means for selecting whether it is a second measurement mode in which contact is made between the two; a storage means for storing the measurement conditions set by the setting means; and the measurement conditions, the diameter d and the distance stored in the storage means. Based on L, the inner diameter or outer diameter D' of the object to be measured is set in advance, where x is the displacement amount of the movable contact from the origin where the base line and the axis intersect. calculation means for determining the origin according to a calculation formula, and the calculation means is configured to determine the measurement conditions among the measurement conditions stored in the storage means when establishing the origin using a master gauge with a known inner diameter or outer diameter D. When the item is the inner diameter, the diameter d is a positive value, and when the item is the outer diameter, the diameter d is a negative value, and when the first measurement mode is selected, a=(D-d)+√[ (D-d)^2-L^2]/2 When the second measurement mode is selected, a=(D-d)-√[(D-d)^2-L^2]/2 An inner and outer diameter measuring device, characterized in that the device is further equipped with a function of determining a from the equation and presetting this value a in the counter. (2) The inner and outer diameter measuring device according to claim 1, wherein the movable ranges of both the fixed contacts and the movable contact are configured to be relatively movable in the axial direction. (3) The inner and outer diameter measuring device according to claim 1 or 2, wherein both the fixed contacts are provided so as to be able to approach and separate from each other at equal distances on the base line. (4) The inner and outer diameter measuring device according to any one of claims 1 to 3, wherein the fixed contact and the movable contact are formed in a spherical shape.