JP7148663B2 - Outer diameter measuring device and its adjustment method - Google Patents

Description

The present invention relates to a contact-type outer diameter measuring device for measuring the outer diameter of, for example, a cylindrical work with high accuracy and an adjustment method thereof, and is particularly suitable for automatic measurement by attaching it to a machine tool or the like.

Conventionally, the dimensional measurement of precision parts and the comparative measurement of sampling are carried out by comparative measurement using a dial gauge with a block gauge or a dedicated master manufactured in advance. These measurements are performed by preparing a master or a measuring table for each measurement dimension, in order to perform comparative measurements with the master, and the operator reads the gauge value and judges whether the part dimensions are within the tolerance. will be Also, when comparatively measuring the outer diameter of a workpiece with design dimensions, the zero point of the detector must be adjusted using a master of the dimensions. This zero-point adjustment must be performed every time the dimension of the workpiece to be measured changes, requiring a great deal of time and labor.

Furthermore, regarding the flexibility and automation of processing machines as a means of production equipment that responds to market trends such as product diversification and shortening of product life, we maintain and monitor processing quality regardless of whether it is small, medium, or mass production. Inline measurement is required. In-line measurement requires highly reliable, highly accurate, and highly efficient measurement under the environment of the machining site. In addition, contact and non-contact in-line measuring instruments are used depending on the required dimensional accuracy and environmental conditions. In order to sufficiently avoid the effects of chips, cutting fluid, temperature fluctuations, mechanical vibrations, etc., a contact-type outer diameter measuring device is widely used in which a contactor is brought into contact with a master or a work.

In-line metrology must contribute to improving the accuracy, stability, efficiency and availability of processing machines, reducing scrap and downtime and increasing efficiency. You have to measure while maintaining time reduction. As a contact-type outer diameter measuring device, there is known a measuring head equipped with a measuring lever that allows easy zero point adjustment, is compact and has a simple structure, and has a contact at the tip that contacts the object to be measured. , for example, in US Pat.

Further, for highly accurate outer diameter measurement, it is necessary to precisely position the workpiece, which is the object to be measured, and to have a small gap when inserting the object to be measured into the guide. Therefore, in the case of a manual machine, workability of loading and unloading is poor, and in the case of an automatic machine, a precision positioning mechanism, a floating mechanism, and a relieving mechanism are required for the loading and unloading equipment.

Regarding the floating mechanism, when fitting the rod-shaped member to the cylindrical member, it is good to ensure that there is no misalignment on the insertion side so that accurate fitting is possible even if the relative positional relationship between the two members is slightly inaccurate. Japanese Patent Application Laid-Open No. 2002-300001 describes that a smooth insertion operation is guaranteed.

Japanese Unexamined Patent Application Publication No. 2004-109110 JP-A-7-96426

In the measuring head described in Patent Document 1, a contact having a spherical or ball tip is used as the contact. A spherical or ball contact is brought into contact with the work, and a radial clearance (a gap for inserting the work) is required between the measuring head and the work. If the work or the measuring head is placed vertically, it may tilt during measurement. Since there are variations in the direction of this tilt, the measurement accuracy becomes unstable.

Moreover, in a manufacturing line, it is common to transport a workpiece in a horizontal posture (a state in which the central axis is extended in the horizontal direction). For this reason, when measuring the diameter of a work, the work is once put in the vertical position during measurement, and then returned to the horizontal position after the measurement. Therefore, highly accurate outer diameter measurement requires precise positioning of the workpiece, which is the object to be measured. Therefore, high precision is required for parts constituting the measuring machine, resulting in high cost.

Also, when a work is inserted into the guide, the gap between the spherical or ball contactor and the work must be as small as 20 to 30 μm on at least one side in order to measure with high accuracy. Therefore, in the case of manual measurement, workability of loading and unloading is poor, and in the case of automatic measurement, a precise positioning mechanism, floating mechanism, and relieving mechanism are required for the loading and unloading equipment. However, the floating mechanism as described in Patent Document 2 has a complicated structure, is difficult to reduce in size, and increases the number of parts, which may lead to an increase in cost and a decrease in reliability.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems of the prior art, and to ensure high accuracy, stable measurement accuracy, and repeatability even when the gap between the guide and the workpiece is relatively large. To eliminate the need for precise positioning of a workpiece, which is an object to be measured, during measurement. Another object is to reduce costs by reducing the cost of the main body of the measuring machine, improving the workability of loading and unloading manual machines, and simplifying the loading and unloading equipment for automatic machines.

The present invention for achieving the above object comprises a measuring lever attached to a head body so as to be swingable in a measuring direction and a retracting direction; a detector for detecting an amount, wherein the contactor is a cylindrical bar contact that sandwiches and abuts the object to be measured; and the contact that sandwiches and abuts the object to be measured. and an angle adjustment mechanism for adjusting the parallelism of the elements, and at least one of the contact elements that sandwiches and abuts the object to be measured is provided on the measurement lever.

Moreover, it is preferable that one of the two contactors is provided on the measuring lever and the other is fixed.

Furthermore, it is desirable that the angle adjustment mechanism is provided on the measurement lever.

Further, the angle adjustment mechanism may include a slit provided in the measuring lever, and a bolt that is inserted into the slit so as to engage with the slit and tightened or loosened to change the interval between the slits. desirable.

Further, it is desirable to provide a guide for inserting the object to be measured and regulating the posture of the object to be measured.

Further, when the diameter of the object to be measured is 7 to 10 mm and the insertion range of the object to be measured into the guide is 40 to 60 mm, the gap between the object to be measured and the guide is 180 to 250 μm on one side. is desirable.

The present invention comprises a measuring lever attached to a head body so as to be capable of swinging in a measuring direction and a retracting direction, a contactor that is a cylindrical bar contact that contacts with the object to be measured sandwiched therebetween, and a displacement of the contactor. and a detector for detecting a quantity, wherein at least one of the contactors that sandwiches and abuts the object to be measured is provided on the measuring lever, A master that serves as a reference is set at the center of the contact in the axial direction to measure the diameter, the master is moved from the center in the axial direction of the contact to measure the diameter, and the change in the measured value changes the diameter of the contact. The angle of the contact is adjusted to make the contact parallel so that the change in diameter is within a permissible value.

In the above, it is desirable to adjust the angle of at least one of the contactors with which the object to be measured is sandwiched.

According to the present invention, the contactors that sandwich and abut against the object to be measured are cylindrical bar contacts, and the measurement lever on which the contactors are provided is provided with an angle adjusting mechanism that makes the two contactors parallel to each other. , it is possible to reduce the measurement error caused by the inclination of the object to be measured. As a result, even if the clearance between the guide and the work is relatively large, high accuracy, stable measurement accuracy and repeatability can be ensured. Therefore, the outer diameter of the object to be measured can be measured easily, accurately and automatically.

1 is a schematic side view of an outer diameter measuring device according to an embodiment of the present invention; FIG. FIG. 2 is a side view showing a state in which a work as an object to be measured is mounted in one embodiment; Top view of main part in FIG. Explanatory diagram showing the influence of workpiece inclination on measurement accuracy Explanatory diagram showing the influence of the outer diameter of the workpiece on the measurement accuracy Explanatory diagram showing the influence of the diameter of the contactor on the measurement accuracy Partial top view showing the effect of contactor parallelism and workpiece position on measurement error FIG. 7 is a partial top view showing an example in which the contacts are adjusted in parallel, similar to FIG. FIG. 4 is a top view showing a contactor angle adjustment mechanism in one embodiment; Flowchart showing an angle adjustment method in one embodiment

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side view showing an outline of an outer diameter measuring apparatus according to one embodiment, FIG. 2 is a side view showing a state in which a workpiece 50 as an object to be measured is mounted on a guide 51 during measurement, and FIG. It is the top view. The head main body 12 is provided with a pair of base levers 14-1 and 14-2, and the measurement direction (arrow A direction) and the retraction direction are centered on spindles 16-1 and 16-2 which are fulcrums inside the detector. (Arrow B direction) is provided so as to be swingable.

Differential transformers 18-1 and 18-, which serve as detectors for detecting the amount of displacement of the base levers 14-1 and 14-2, are provided at the base ends (lower ends in the drawing) of the base levers 14-1 and 14-2. 2 is provided. The differential transformers 18-1, 18-2 are composed of cores 18-1A, 18-2A and bobbins 18-1B, 18-2B. The cores 18-1A, 18-2A are fixed to the base ends of the base levers 14-1, 14-2, and the bobbins 18-1B, 18-2B are fixed to the head body 12.

Further, springs 20-1 and 20-2 are attached to the base ends of the base levers 14-1 and 14-2. By the biasing force of the springs 20-1 and 20-2, the base levers 14-1 and 14-2 are biased in the arrow A direction (the direction in which the tips of the base levers 14-1 and 14-2 approach each other), which is the measurement direction. It is

Nut portions 26-1 and 26-2 are formed at the tip portions (upper ends in the drawing) of the base levers 14-1 and 14-2. , 28-2 are provided. Two measurement levers 32-1 and 32-2, which are bar contact fingers, are provided on the shafts 28-1 and 28-2 so as to be capable of angle adjustment.

Contactors 34-1 and 34-2, which are cylindrical bar contacts, are attached to the tips of the measurement levers 32-1 and 32-2, respectively. The outside diameter of the workpiece 50 is measured by bringing it into contact with the workpiece 50 to be measured. The contactors 34-1 and 34-2 are portions that directly contact a cylindrical workpiece 50, which is an object to be measured, as a displacement sensor.

The contactors 34-1 and 34-2 are arranged so that their axial directions are orthogonal to the axial direction of the work 50, and are in contact with the work 50 while sandwiching it. A ball contact, a spherical contact, a roller contact, a circular flat contact, and the like are known as the contact. The contactors 34-1 and 34-2 are cylindrical bar contacts so that the workpiece 50 can be easily carried in and out of the guide 51 and the repeatability is ensured even if the gap between the workpiece 50 and the guide 51 is large. there is

FIG. 2 shows a state in which the work 50 is mounted on the guide 51. Since the inclination of the work 50 greatly affects the measurement accuracy, it serves as a guide when the work 50 is inserted from above as shown in the figure, and the posture of the work 50 is adjusted. required for regulation. In measuring the outer diameter of the workpiece 50 configured in this manner, the guide 51 is positioned precisely, and then the workpiece 50 is inserted into the hole of the guide 51. When the workpiece 50 is positioned at a predetermined depth, the two contactors 34-1, 34-2 is brought into contact with the workpiece 50;

At this time, the measurement levers 32-1 and 32-2 rotate around the support shafts 16-1 and 16-2, and the cores 18- fixed to the base ends of the base levers 14-1 and 14-2 are rotated. 1A, 18-2A are displaced. When the contacts 34-1 and 34-2 come into contact with the workpiece 50, the differential transformers 18-1 and 18-2, which serve as displacement detectors, detect the amount of displacement and generate a signal corresponding to the amount of displacement. is output as the outer diameter of the workpiece 50 .

FIG. 3 mainly shows measurement levers 32-1 and 32-2 and contactors 34-1 and 34-2 facing each other for sandwiching the workpiece 50. FIG. One measurement lever 32-1 has an angle adjusting mechanism in the A and B directions by means of slits 35-1, 35-2 and bolts 36-1, 36-2.

That is, the bolts 36-1 and 36-2 are inserted so as to engage with the slits 35-1 and 35-2, and when the bolts 36-1 and 36-2 are tightened or loosened, the slits 35-1 are inserted. , 35-2 is changed to elastically deform the measuring lever 32-1. Thereby, the angle of the contactor 34-1 with respect to the contactor 34-2 can be adjusted to make the contactor 34-1 and the contactor 34-2 parallel more strictly.

FIG. 4 shows the influence of inclination (inclination) of the workpiece 50 on measurement accuracy. -1, 34-2 showing the effect of diameter. FIG. 4A shows the case where the workpiece 50 is not tilted, the diameters of the contacts 34-1 and 34-2 are 2 mm, and the outer diameter of the workpiece 50 is 7 mm. In this case, the distance between the centers of the contacts 34-1 and 34-2 is 9 mm.

FIG. 4B shows the case where the workpiece 50 is tilted by 1°, and the distance between the centers of the contacts 34-1 and 34-2 is (1/cos (1°))×9=9.00137 mm.

FIG. 4(c) shows the case where the workpiece 50 is tilted at 5°, and the distance between the centers of the contacts 34-1 and 34-2 is similarly 9.03438 mm. That is, if the workpiece 50 is tilted, the error is in the direction of increasing the diameter, and the greater the tilt, the greater the measurement error. Therefore, as shown in FIG. 2, it is important to regulate the posture of the workpiece 50 with the guide 51 so that the inclination is as small as possible.

FIG. 5 similarly shows the influence of the inclination of the work 50 by increasing the outer diameter of the work 50 to 17 mm compared to FIG. FIG. 5(a) shows the case where the workpiece 50 is not tilted, and the distance between the centers of the contacts 34-1 and 34-2 is 19 mm. FIG. 5B shows the case where the workpiece 50 is tilted by 1°, and the distance between the centers of the contacts 34-1 and 34-2 is 19.00289 mm.

FIG. 5C shows the case where the workpiece 50 is tilted at 5°, and the distance between the centers of the contacts 34-1 and 34-2 is 19.07258 mm. That is, even if the inclination is the same, the larger the outer diameter of the workpiece 50, the larger the measurement error.

FIG. 6 similarly shows the influence of the inclination of the workpiece 50 when the diameters of the contacts 34-1 and 34-2 are increased to 4 mm. The diameters of the contacts 34-1 and 34-2 are 4 mm, and the outer diameter of the workpiece 50 is 7 mm. FIG. 6(a) shows the case where the work 50 is not tilted, and the distance between the centers of the contacts 34-1 and 34-2 is 11 mm. FIG. 6B shows the case where the workpiece 50 is tilted by 1°, and the distance between the centers of the contacts 34-1 and 34-2 is 11.00168 mm.

FIG. 6C shows the case where the workpiece 50 is tilted at 5°, and the distance between the centers of the contacts 34-1 and 34-2 is 11.04202 mm. That is, even if the inclination is the same, the larger the diameter of the contacts 34-1 and 34-2, the larger the measurement error.

FIG. 7 is a partial top view showing the influence of the parallelism of the contacts 34-1 and 34-2, which are cylindrical bar contacts, and the position of the workpiece 50 on the measurement error. The workpiece 50 may be moved or shifted in the directions A, B, C, and D as shown in FIG. 7A with respect to the contacts 34-1 and 34-2. FIGS. 7(b), 7(c) and 7(d) illustrate the case where the contacts 34-1 and 34-2 are not parallel.

FIG. 7(b) shows the case where the work 50 is positioned at the center between the contacts 34-1 and 34-2, and FIG. 7(c) shows the case where the work 50 is shifted upward in the A direction. is a case of shifting downward in the B direction. The measuring pressure is applied to the axial centers of the contacts 34-1 and 34-2.

Using FIG. 7(b) as a reference, in FIG. 7(c), the work 50 is positioned at a position where the distance between the contacts 34-1 and 34-2 is small, so the outer diameter of the work 50 is larger than it actually is. produce a measured error. Conversely, in FIG. 7(d), the work 50 is positioned at a position where the distance between the contacts 34-1 and 34-2 is large, so the outer diameter of the work 50 is measured smaller than the actual one.

When the workpiece 50 moves in the C and D directions, the difference between the two differential transformers 18-1 and 18-2 that detect the amount of displacement is calculated as the outer diameter of the workpiece 50. does not occur. Therefore, although there is no problem in the C and D directions, the work 50 must be precisely positioned in the A and B directions, and the gap between the work 50 and the guide 51 must be reduced.

FIG. 8 shows, like FIG. 7, an example in which the contacts 34-1 and 34-2, which are cylindrical bar contacts, are adjusted in parallel. As can be seen from FIG. 8, if the contacts 34-1 and 34-2 are parallel, even if the work 50 is displaced in the A and B directions, no measurement error will occur. Therefore, by increasing the gap between the workpiece 50 and the guide 51, it is possible to improve the workability of loading and unloading the workpiece 50 during measurement, simplify the loading and unloading equipment of the automatic machine, and reduce the cost of the measuring machine main body.

FIG. 9 is a top view showing an angle adjustment mechanism for parallelizing the contacts 34-1 and 34-2, and FIG. 10 is a flow chart showing the angle adjustment method. As described with reference to FIG. 3, one measuring lever 32-1 has an angle adjusting mechanism in the A and B directions by means of slits 35-1, 35-2 and bolts 36-1, 36-2. The other measurement lever 32-2 does not have an angle adjustment mechanism. A master 52 with high roundness is used as the object to be measured for angle adjustment.

The master 52 is set at the axial center of the cylindrical bar contacts 34-1 and 34-2. If the master 52 is moved in the A direction and the measured value increases, the state shown in FIG. As a result, the interval between the slits 35-2 increases, and the angle of the contactor 34-1 changes as shown in FIG. Contacts 34-1 and 34-2 can be run in parallel.

Similarly, if the master 52 is moved in the B direction and the measured value increases, the state shown in FIG. As a result, the interval between the slits 35-1 increases, and the angle of the contactor 34-1 changes as shown in FIG. Contacts 34-1 and 34-2 can be run in parallel.

When the above adjustment is performed and the master 52 is moved in the A direction and the B direction, the measured values do not fluctuate, it means that the contacts 34-1 and 34-2 are parallel. Then, the bolts 36-1 and 36-2 are fixed, and the parallel adjustment is completed. After the parallel adjustment is completed, the master 52 is used to move in the A direction and the B direction.

FIG. 10 is a flow chart showing the above procedure. First, the master 52 with high roundness is set at the center of the contactors 34-1 and 34-2 in the axial direction and the diameter is measured. The master 52 is moved from the center in the A and B directions, which are the axial directions of the contacts 34-1 and 34-2, and the diameter is similarly measured. Then, the angle is adjusted so that the contactors 34-1 and 34-2 are parallel to each other according to the change in the diameter measurement value.

Specifically, when the stencil 52 is moved in the A direction, if the measured diameter becomes larger than when it is set at the center, the state shown in FIG. and push it in. When the stencil 52 is moved in the B direction, if the measured diameter becomes larger than when it is set at the center, it is in the state of FIG. 9(c), and the bolt 36-1 is tightened and pushed. The above steps are repeated until the diameter does not change or is within the tolerance.

Next, the bolts 36-1 and 36-2 are fixed by tightening the fixing bolt 35-3 shown in FIG. In this state, the master 52 is again set at the center of the contactors 34-1 and 34-2 in the axial direction, and the diameter is measured. The master 52 is moved in the A and B directions and the diameter is similarly measured to confirm that there is no change in the diameter or that it is within the allowable range. If there is a change in diameter, loosen the bolts 36-1 and 36-2 and start over.

As described above, using the cylindrical bar contacts 34-1 and 34-2, at least one of the angle adjusting mechanisms (the slits 35-1 and 35-2 and the bolts 36-1 and 36-2 in FIG. ) is provided. As a result, the cylindrical bar contacts can be made exactly parallel, and positional accuracy in the y direction (the AB direction in FIG. 7) of the workpiece 50, which is the object to be measured, is not required.

In addition, in the x direction (CD direction in FIG. 7), if the detection magnification of the differential transformers 18-1 and 18-2, which are detectors, is the same, they are offset at any position and the measured value is stable. do. Even if the gap between the object to be measured and the guide is increased, highly accurate measurement is possible. In addition, carrying in and out of the object to be measured is facilitated. Specifically, it is possible to guarantee a repeatability of 1 μm or less with a gap that is five times greater than that of conventional measuring instruments. Although the detector has been described as a differential transformer, the same applies if it is a displacement measuring device such as an optical system.

Furthermore, the smaller the diameter of the cylindrical bar contacts 34-1 and 34-2, the smaller the measurement diameter of the object to be measured, the smaller the measurement error. As a result of diligent research by the present inventors, it has been found that the diameter of the contactors 34-1 and 34-2 is practically 2 to 4 mm and is suitable with small error.

If the measurement pressure shown in FIG. 7 is made different and one side is set to a low measurement pressure, the measurement value is stabilized. This is effective not only when measuring an object to be measured, but also when measuring a master for adjusting the angle of the contactor 34-1. In addition, although the two measurement levers 32-1 and 32-2 that are freely swingable have been described, the measurement lever 32-2 that is not provided with an angle adjustment mechanism has a smaller amount of swinging, or is substantially fixed. Even if the cylindrical bar contacts 34-1 and 34-2 are applied to an object, there is an effect of reducing the error due to the inclination of the object to be measured.

According to the above, only the inclination due to the inclination of the object to be measured becomes an error factor. In addition, by using a small-diameter bar contact, this error factor can be reduced. Specifically, when the diameter of the bar contact is 1 mm and the inclination is 0.5°, the error can be improved to about 0.4 μm.

Furthermore, although it depends on the diameter of the workpiece 50, which is the object to be measured, and the guide 51 for regulating the inclination of the object to be measured, even if the gap is about 1.5 to 10 times that of the conventional one, a repeatability of about 1 μm is achieved. became possible. Specifically, when the diameter of the object to be measured was 7 to 10 mm and the guide insertion range was 40 to 60 mm, the repeatability was 1 μm with a gap of 180 to 250 μm on one side. Conventionally, a gap of 30 μm on one side was required to achieve a repeatability of 1 μm.

As a result, the accuracy of the loader that carries the work 50 in and out of the outer diameter measuring device can be lowered. In the case of an automatic machine, a precision positioning mechanism, a floating mechanism, and a relieving mechanism can be provided at a low cost in the loading/unloading equipment.

In addition, since it is sufficient to replace the measuring lever with respect to the conventional outer diameter measuring device, there is no need to replace the detector and the like, and the increase in cost can be minimized. Furthermore, the process of measuring workpieces after machining in machine tools and dedicated machines is accelerated, and work efficiency is improved.

12... Head body 14-1, 14-2... Base lever 16-1, 16-2... Support shaft 18-1, 18-2... Differential transformer (detector)
18-1A, 18-2A... Core 18-1B, 18-2B... Bobbin 20-1, 20-2... Spring 26-1, 26-2... Nut part 28-1, 28-2... Shaft part 32-1 , 32-2... Measurement lever 34-1, 34-2... Contact 35-1, 35-2... Slit 35-3... Fixing bolt 36-1, 36-2... Bolt 50... Work 51... Guide 52... Master

Claims (7)

A measurement lever attached to a head body so as to be swingable in a measurement direction and a retraction direction, a contact provided on the measurement lever and brought into contact with an object to be measured, and a detector for detecting the amount of displacement of the contact. In an outer diameter measuring device equipped with
the contactor, which is a cylindrical bar contact that sandwiches and abuts the object to be measured;
an angle adjustment mechanism that adjusts the parallelism of the contactors that sandwich and contact the object to be measured;
wherein at least one of the contactors that clamps and abuts on the object to be measured is provided on the measuring lever, and the other is fixed . 2. The outer diameter measuring device according to claim 1, wherein the angle adjusting mechanism is provided on the measuring lever. The angle adjustment mechanism is
a slit provided in the measuring lever;
a bolt that is inserted so as to engage with the slit and is tightened or loosened to change the interval between the slits;
The outer diameter measuring device according to claim 2 , characterized by comprising: 4. The outer diameter measuring apparatus according to any one of claims 1 to 3 , further comprising a guide for inserting the object to be measured and regulating the posture of the object to be measured. When the diameter of the object to be measured is 7 to 10 mm and the insertion range of the object to be measured into the guide is 40 to 60 mm, the gap between the object to be measured and the guide is 180 to 250 μm on one side. The outside diameter measuring device according to claim 4 . a measurement lever attached to the head body so as to be swingable in the measurement direction and the retraction direction;
A method for adjusting an outer diameter measuring device comprising: a cylindrical bar contact that sandwiches and abuts an object to be measured; and a detector that detects the amount of displacement of the contact.
At least one of the contactors that sandwiches and abuts the object to be measured is provided on the measurement lever, and a master serving as a reference for the object to be measured is set at the center of the contactor in the axial direction to measure the diameter, The master is moved from the center in the axial direction of the contact, the diameter is measured, the angle of the contact is adjusted according to the change in the measured value, and the contact is made so that the change in the diameter is within the allowable value. A method for adjusting an outer diameter measuring device, characterized in that the elements are parallel. 7. The method for adjusting an outer diameter measuring device according to claim 6 , wherein the angle of at least one of the contactors with which the object to be measured is held is adjusted.

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