JP2014077765A - Circularity measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circularity measuring device, small in space required for installation, and small in error due to temperature fluctuations.SOLUTION: The circularity measuring device includes: a base 21; a rotary table 22 fixed to the base and making a mounted work rotate; two-dimensional moving mechanisms 24, 25, 51 to 55, and 71 to 75 for enabling a holder fixing part to move in parallel with a measurement plane including a rotation axis of the rotary table and a measurement point of the work; a detector holder 29 attached to the holder fixing part; and a detector 30 attached to the detector holder for enabling a measuring element 31 to displace in the measurement plane.

Description

  The present invention relates to a roundness measuring apparatus.

  A roundness measuring device that measures the roundness of a cylindrical outer peripheral surface or inner peripheral surface of an object to be measured (workpiece) is widely used.

FIG. 1 is an external view of a conventional roundness measuring apparatus.
The roundness measuring device includes a base 1 having a base, a rotatable stage 2 provided on the base 1, a rotation drive unit 3 having a motor for rotationally driving the stage 2, and a base. 1, a carriage 5 movable along the column 4, an arm 6 movable relative to the carriage 5, a detector holder 9 attached to the tip of the arm 6, and a detector And a detector 10 attached to the holder 9. The detector 10 includes a measuring element 11 and a displacement detection unit such as a differential transformer, and outputs an electrical signal indicating the displacement of the measuring element 11.

  The workpiece 12 is placed on the table 2 and rotated so that the central axis of the cylindrical surface of the workpiece 12 substantially coincides with the rotation axis of the table 2. The column 4 is a column extending in parallel with the rotation axis of the mounting table 2. The carriage 5 is movable along the column 4 and is generally moved manually along the guide surface of the column 4, but may be automatically moved using a motor or the like. The arm 6 is manually moved to the guide surface of the carriage 5, but may be automatically moved using a motor or the like. The detector holder 9 is an L-shaped member, with one end attached to the tip of the arm 6 and the detector 10 attached to the other end. In order to detect a change in the height position of the brim portion of the work 12, the detector holder 9 may be able to be attached to the tip of the arm 6 in three different directions by 90 degrees. Furthermore, the detector 10 may be attached to the detector holder 9 by changing the direction in order to change the direction of the cylindrical surface to be measured by 180 degrees.

  When performing measurement, the workpiece 12 is placed on the mounting table 2 such that the central axis of the cylindrical surface of the workpiece 12 substantially coincides with the rotation axis of the mounting table 2. The carriage 5 is moved to adjust the vertical position so that the probe 11 contacts the position measured by the workpiece 12, and the arm 6 is moved to adjust the radial position. In this state, the roundness of the workpiece 12 is measured. When high-precision measurement is performed, the workpiece 12 is rotated, and the center axis of the cylindrical portion of the workpiece 12 and the rotation axis of the mounting table 2 are rotated. The eccentricity is measured, and the XY movement mechanism provided on the mounting table 2 is adjusted so that the central axis of the cylindrical portion of the workpiece 12 accurately matches the rotation axis of the mounting table 2. At this time, it is desirable that the measuring element 11 is near the center of the displacement range.

FIG. 2 is a top view of the roundness measuring apparatus of FIG.
As shown in FIG. 2, the column 4 is provided on the right side of the mounting table 2. The arm 6, the detector holder 9, and the detector 10 are arranged on a straight line, and the rotation center axis of the stage 2 is positioned on the extension. The measuring element 11 is provided at the tip of the detector 10 and is displaced in a plane formed by this straight line and the rotation center axis of the mounting table 2. Therefore, when the diameter of the cylindrical surface to be measured by the workpiece 12 is different, the arm 6 is moved so that the probe 11 contacts the cylindrical surface to be measured. Here, the plane formed by the measurement point in contact with the cylindrical surface measured by the probe 11 and the rotation center axis of the mounting table 2 is referred to as a measurement plane, and the direction between the rotation center axis of the mounting table 2 and the measurement point is the diameter. It is called a direction. In other words, even when the diameter of the cylindrical surface to be measured is different, the arm 6, the detector holder 9, and the detector 10 are moved in the radial direction along the measurement plane, and the measuring element 11 is an intersection of the measurement plane and the cylindrical surface. It touches the cylindrical surface on the line to be moved and is displaced on the measurement plane.

  The first reason for providing the column 4 on the right side of the stage 2 (or the left side) is to move the arm 6 on the measurement plane, and the second reason is that when measuring different cylindrical surfaces, This is because the difference in the radius (diameter) of the cylindrical surface can be detected by detecting the movement amount of the arm 6.

  For the reasons described above, in the conventional roundness measuring device, the column 4 is provided on the side (right side or left side) of the mounting table 2. Therefore, the base 1 to which the column 4 is fixed is a rectangle that is long in the radial direction in the top view. Furthermore, since the arm 6 is moved in the radial direction according to the radius of the cylindrical surface to be measured, it is necessary to determine the installation space in consideration of the case where the arm 6 has moved to the maximum in the right direction. For the reasons as described above, the conventional roundness measuring apparatus has a problem that a rectangular installation space that is long in the radial direction is required, and the space required for the installation is large.

  In addition, since the conventional roundness measuring device has the long arm 6, if there is a small amount of temperature change even during a short time during measurement, the displacement of the detector 10 attached to the tip of the arm 6 and the detector holder 9 will be described. However, since the displacement directly affects the measured value, there is a problem that an error due to a temperature change is large.

JP-A-8-313247 Japanese Patent No. 2606787 JP-A-1-259211

  An object of the present invention is to realize a roundness measuring apparatus that requires a small space for installation and that has a small measurement error due to temperature conversion.

  In order to solve the above problems, the roundness measuring device of the present invention is provided with a two-dimensional movement mechanism for moving the holder fixing portion parallel to the measurement plane on the back surface of the base, and further including a detector holder on the holder fixing portion. A detector is attached to the detector holder so that the probe can be displaced in the measurement plane.

  That is, the roundness measuring device of the present invention is a measurement including a base, a turntable fixed to the base and rotating a mounted work, a holder fixing portion, a rotation axis of the turntable, and a work measurement point. It is attached to the detector holder so that the two-dimensional movement mechanism provided on the base so as to move parallel to the plane, the detector holder attached to the holder fixing part, and the probe can be displaced on the measurement plane. And a detector.

  According to the present invention, since the two-dimensional movement mechanism is provided on the back surface of the base, the installation space can be made a shape close to a square, and the installation space (the space necessary for installation) can be reduced.

  Further, in the conventional roundness measuring apparatus of FIG. 1, the detector is attached to an arm and a detector holder extending from the column along the measurement plane. Therefore, when the arm expands or contracts due to a temperature change, the amount of expansion or contraction directly affects the measured value. When the arm is long, even if the temperature changes in a short time during measurement, the amount of expansion and contraction of the arm becomes a size that cannot be ignored, resulting in a measurement error.

  On the other hand, according to the present invention, since a long arm is not used and the measuring instrument holder extends from the two-dimensional movement mechanism in a direction perpendicular to the measuring plane, even if the measuring instrument holder expands and contracts due to a temperature change, Since the amount of expansion / contraction does not directly affect the measured value, the influence of the temperature change on the measurement error can be reduced.

  The two-dimensional moving mechanism supports a first column that extends parallel to the rotation axis of the turntable and moves parallel to the measurement plane, and a holder fixing portion so as to be movable along the first column, that is, in the vertical direction. It is desirable to include a first fixing part moving mechanism. By moving the first column parallel to the measurement plane according to the radius of the cylindrical surface to be measured, the probe is brought into contact with the cylindrical surface. Further, by moving the holder fixing portion along the first column by the first fixing portion moving mechanism, the vertical position, that is, the height of the contact point with the cylindrical surface of the measuring element is adjusted.

  It is desirable that the moving mechanism that moves the first column parallel to the measurement plane includes a guide mechanism that holds the column parallel to the rotation axis of the turntable and a feed mechanism that moves the column.

  It is also possible to provide two independently movable columns so that the roundness can be measured simultaneously at two locations on the workpiece. This makes it possible to measure the diameter, minimizing the deflection even for elongated workpieces. Measurement.

  The two column moving mechanisms share a guide mechanism for holding the two columns parallel to the rotation axis of the turntable, and it is desirable that the feeding mechanism be provided independently.

  Further, the two-dimensional moving mechanism includes a column extending parallel to the rotation axis of the turntable, a moving unit supported so as to be movable along the column, and a holder fixing unit parallel to the measurement plane. And a fixed portion moving mechanism that moves to the position. In this case, since the column is fixed, the fixed portion moving mechanism can be reduced in size.

  ADVANTAGE OF THE INVENTION According to this invention, the roundness measuring apparatus with a small space required for installation is implement | achieved.

FIG. 1 is an external view of a conventional roundness measuring apparatus. FIG. 2 is a top view of the roundness measuring apparatus of FIG. FIG. 3 is an external view of the roundness measuring apparatus according to the first embodiment of the present invention as seen from the front side. FIG. 4 is an external view of the roundness measuring apparatus according to the first embodiment of the present invention viewed from the back side. FIG. 5 is a top view of the roundness measuring apparatus according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating a state in which the roundness is measured by bringing the measuring element into contact with the outer cylinder surface on the left side with respect to the rotation axis of the mounting table in the roundness measuring apparatus according to the first embodiment. FIG. 7 is a diagram for explaining the difference in the influence of the displacement of the probe due to the temperature change in the first embodiment and the conventional example shown in FIG. FIG. 8 is an external view seen from the front side of the roundness measuring apparatus according to the second embodiment of the present invention. FIG. 9 is an external view of the roundness measuring apparatus according to the second embodiment of the present invention viewed from the back side. FIG. 10 is an external view of a roundness measuring apparatus according to the third embodiment of the present invention.

  3 and 4 are external views of the roundness measuring device according to the first embodiment of the present invention as seen from the front side and the back side.

  The roundness measuring apparatus according to the first embodiment includes a table-like base 21, a rotatable table 22 provided on the base 21, and a rotational drive having a motor for rotationally driving the table 22. (Not shown), a column 24 provided on the back surface of the base 21, a carriage 25 movable along the column 24, a detector holder 29 attached to the carriage 25, and attached to the detector holder 29 Detector 30. The detector 30 has a probe 31 and a displacement detector such as a differential transformer, and outputs an electrical signal indicating the displacement of the probe 31. Since the detector holder 29 is attached, the carriage 25 is also referred to as a holder fixing portion.

  The column 24 is provided with vertical guides 51 and 52 and a vertical feed screw 53. The carriage 25 is engaged with the vertical feed screw 53 by a vertical feed nut. When the vertical feed knob 55 is rotated, the vertical feed screw 53 is rotated to move in the vertical direction. Instead of the vertical feed knob 55, a motor or the like that rotationally drives the vertical feed screw 53 may be provided to move the carriage 25 in the vertical direction. Since the carriage 25 is guided by the highly accurate vertical guides 51 and 52, the posture does not change even if it moves. Therefore, even if the detector holder 29 and the detector 30 attached to the carriage 25 move in the vertical direction, the posture does not change, and only the position (height) in the vertical direction changes.

  Further, radial guides 71 and 72 and a radial feed screw 73 are provided on the back surface of the base 21. The column 24 is engaged with the radial feed screw 73 by a radial feed nut 74, and rotating the radial feed knob 75 causes the radial feed screw 73 to rotate and move parallel to the radial direction. The column 24 is movable to the right side and the left side of the stage 22. Instead of the radial feed knob 75, a motor or the like that rotationally drives the radial feed screw 73 may be provided to move the column 24 parallel to the radial direction. Since the column 24 is guided by the high-precision radial guides 71 and 72, the posture does not change even if it moves. Therefore, even if the detector holder 29 and the detector 30 attached to the column 24 (carriage 25) move in parallel with the radial direction, the posture does not change, and only the radial position changes. In other words, in order to measure the roundness of cylindrical surfaces having different radii, even if the column 24 is moved parallel to the radial direction, the probe 31 of the detector 30 contacts the workpiece 32 on the measurement plane.

  The detector holder 29 and the detector 30 are the same as those of the conventional example shown in FIG. As described above, in order to detect a change in the height position of the collar portion of the work 32, it is desirable that the detector holder 29 can be attached to the carriage 25 in three different directions by 90 degrees. Furthermore, it is desirable that the detector 30 can be attached to the detector holder 29 by changing the direction in order to change the direction of the cylindrical surface to be measured by 180 degrees.

  When performing the measurement, the workpiece 32 is placed on the mounting table 22 such that the central axis of the cylindrical surface of the workpiece 32 substantially coincides with the rotation axis of the mounting table 22. The carriage 25 is moved to adjust the vertical position so that the probe 31 contacts the position to be measured by the workpiece 32, and the column 24 is moved to adjust the radial position. In this state, the roundness of the workpiece 32 is measured. When high-precision measurement is performed, the workpiece 32 is rotated, and the center axis of the cylindrical portion of the workpiece 32 and the rotation axis of the mounting table 22 are rotated. The eccentricity is measured, and the measurement is performed after the center axis of the cylindrical portion of the work 32 is adjusted to be exactly coincident with the rotation axis of the mounting table 22 by the XY moving mechanism provided on the mounting table 22. At this time, it is desirable that the probe 31 is near the center of the displacement range.

FIG. 5 is a top view of the roundness measuring apparatus according to the first embodiment.
As shown in FIG. 5, the column 24 is provided on the back surface of the stage 22 so as to be movable in parallel with the measurement plane. The detector holder 29 extends from the carriage 25 in a direction perpendicular to the measurement plane, and the detector 30 is attached so that the probe 31 is displaced on the measurement plane. When the diameters of the cylindrical surfaces to be measured by the workpiece 32 are different, the column 24 is moved in parallel with the measurement plane, so that the detector holder 29 and the detector 30 are moved in the radial direction along the measurement plane. 31 contacts the cylindrical surface on a line intersecting the measurement plane and the cylindrical surface, and is displaced on the measurement plane.

  As is clear from comparison between FIG. 2 and FIG. 5, the roundness measuring device of the first embodiment has a significantly longer lateral (radial) length of the base than the conventional roundness measuring device. It can be seen that the installation space is greatly reduced because the arm does not protrude sideways.

  As described above, in the conventional roundness measuring device, the difference in the radius (diameter) of the cylindrical surface can be detected by detecting the movement amount of the arm 6, but the roundness measuring device of the first embodiment. However, similarly, it can be detected by detecting the amount of movement of the column 24.

  When measuring the roundness of the inner cylindrical surface of the workpiece 32 with the roundness measuring device of the first embodiment, the inner cylindrical surface on the opposite side of the measurement point of FIG. Measured by contacting the probe 31 to

  FIG. 6 is a diagram showing a state in which the roundness is measured by bringing the probe 31 into contact with the outer cylinder surface on the left side with respect to the rotation axis of the mounting table 22 in the roundness measuring apparatus of the first embodiment. is there. In this case, as compared with the case of FIG. 3, the detector 30 is rotated 180 degrees and attached to the attachment portion 33 of the detector holder 29.

  FIG. 7 is a diagram for explaining the difference in the influence of the displacement of the probe due to the temperature change in the first embodiment and the conventional example shown in FIG.

  When a temperature change occurs, each part expands and contracts. However, the heat capacity of the base and column is large, and if the time is short, such as one measurement time, the temperature change is relatively small, and the amount of expansion and contraction resulting from the change is small. On the other hand, the arm and the detector holder have a small heat capacity and expand and contract due to temperature changes even in a short time. For example, if the arm is made of iron and is 100 mm, the expansion / contraction amount is 1 μm even if the temperature changes by 0.1 ° C.

  In the conventional example shown in FIG. 1, as shown in FIG. 7A, when the arm 6 and the detector holder 9 expand and contract due to a temperature change, the displacement d of the tip of the probe is generated in the measurement plane. The correct position 33 is displaced to the position indicated by 33a. Therefore, this displacement d becomes a deviation of the surface position of the workpiece, that is, a measurement error as it is. In the roundness measuring apparatus, a measurement error of 1 μm is a level that cannot be ignored.

  On the other hand, in the first embodiment, since the long arm is not used, the displacement of the probe is small in the first place. Furthermore, in the first embodiment, as shown in FIG. 7A, when the detector holder 9 expands and contracts due to a temperature change, the displacement d of the tip of the probe occurs in a plane perpendicular to the measurement plane. Then, the correct position 33 is displaced to the position indicated by 33b. Due to this displacement, the probe deviates from the measurement plane, but a pressure that makes contact with the workpiece is applied, and as shown in FIG. 7B, the probe contacts the surface of the cylindrical workpiece. The deviation Δ in the measurement direction at this time is very small when the displacement d is small and θ is small. Specifically, assuming that the radius of the workpiece is R, θ = sin (d / R) and Δ = R (1−cos θ). As described above, in the first embodiment, even if there is a temperature change, the influence on the measurement error is small.

  8 and 9 are external views of the roundness measuring device according to the second embodiment of the present invention as seen from the front side and the back side.

  The roundness measuring device of the second embodiment is different from the roundness measuring device of the first embodiment in that it has two sets of a column, a carriage, a detector holder, and a detector.

  As shown in the figure, the roundness measuring apparatus of the second embodiment includes a base 21, a table 22, a rotation drive unit (not shown), two columns 24 A and 24 B, 2 It has two carriages 25A and 25B, two detector holders 29A and 29B, and two detectors 30A and 30B.

The column 24A is provided with vertical guides 51A and 52A and a vertical feed screw 53A. The carriage 25A is engaged with the vertical feed screw 53A by a vertical feed nut. When the vertical feed knob 55A is rotated, the vertical feed screw 53A is rotated and moved in the vertical direction. Similarly, the column 24B is provided with vertical guides 51B and 52B and a vertical feed screw 53B. The carriage 25B is engaged with the vertical feed screw 53B by a vertical feed nut. When the vertical feed knob 55B is rotated, the vertical feed screw 53B is rotated to move in the vertical direction.
Further, radial guides 71 and 72 and two radial feed screws 73A and 73B are provided on the back surface of the base 21. The column 24A is engaged with the radial feed screw 73A by a radial feed nut. When the radial feed knob 75A is rotated, the radial feed screw 73A rotates and moves parallel to the radial direction. Similarly, the column 24B is engaged with the radial feed screw 73B by a radial feed nut 74B, and rotating the radial feed knob 75B causes the radial feed screw 73B to rotate, parallel to the radial direction. Moving. Since the columns 24A and 24B are guided by the high-precision radial guides 71 and 72, their postures do not change even if they are moved. The detector holders 29A and 29B and the detectors 30A and 30B are the same as those in the first embodiment, and the attachment direction of the detector holder 29B of the detector 30B is the attachment direction of the detector holder 29A of the detector 30A. And 180 degrees different.

  FIG. 8 shows that the measuring elements 31A and 31B of the detectors 30A and 30B are brought into contact with two points symmetrical to the rotation axis of the mounting table 22 on the outer cylindrical surface, that is, two points corresponding to the diameter of the outer cylindrical surface. Indicates the state. By calculating the change in the sum of the detection signals of the detectors 30A and 30B in this state, the change in the diameter of the outer cylinder surface can be measured.

FIG. 10 is an external view of a roundness measuring apparatus according to the third embodiment of the present invention.
In the roundness measuring apparatus of the third embodiment, the column 24 is fixed and the carriage 25 is provided with a detector holder moving mechanism 81 that moves the detector holder 29 parallel to the measurement plane. Different from the roundness measuring apparatus of the first embodiment.

  In FIG. 10, the movement mechanism of the carriage 25 provided in the column 24 is not shown, but a movement mechanism similar to that of the first embodiment is provided.

  The detector holder moving mechanism 81 is realized by a moving mechanism similar to the first embodiment, which is fixed to the carriage 25 and has a pair of guides, a feed screw, and a feed nut. Yes. The detector holder moving mechanism 81 moves the holder fixing portion to which the detector holder 29 is attached in a direction parallel to the measurement plane and perpendicular to the load 22nd rotation axis.

  In the roundness measuring device of the third embodiment, similarly to the roundness measuring device of the first embodiment, when the diameter of the cylindrical surface measured by the workpiece 32 is different, the detector holder 29 and the detector 30 are The probe 31 is moved in the radial direction along the measurement plane, and the probe 31 comes into contact with the cylindrical surface on a line intersecting the measurement plane and the cylindrical surface, and is displaced on the measurement plane. Moreover, the roundness measuring apparatus of 3rd Embodiment becomes installation space significantly small similarly to the roundness measuring apparatus of 1st Embodiment.

  The first to third embodiments have been described above. In any of the embodiments, the column is provided on the back side of the turntable, and the detector holder 29 and the detector 30 move in the radial direction along the measurement plane. Is done. In other words, a two-dimensional movement mechanism that moves a holder fixing portion (carriage or the like) to which the detector holder 29 is attached in two dimensions parallel to the measurement plane is provided on the back side of the base. As a result, the installation space can be reduced while satisfying the essential items of roundness measurement.

  As mentioned above, although embodiment of this invention was described, it cannot be overemphasized that various modifications are possible.

  The present invention is applicable to a roundness measuring device and a measuring device having a similar function.

21 Base 22 Loading table 24 Column 25 Carriage 29 Detector holder 30 Detector 31 Measuring element 32 Workpiece

Claims (6)

Base and
A turntable that is fixed to the base and rotates the mounted workpiece;
A two-dimensional movement mechanism provided on the base so as to move the holder fixing portion in parallel to a measurement plane including a rotation axis of the turntable and a measurement point of the workpiece;
A detector holder attached to the holder fixing part;
A roundness measuring apparatus comprising: a detector attached to the detector holder so that a measuring element can be displaced in the measurement plane. The two-dimensional movement mechanism is
A first column extending parallel to the rotation axis of the turntable and moving parallel to the measurement plane;
The roundness measuring device according to claim 1, further comprising: a first fixing portion moving mechanism that movably supports the holder fixing portion along the first column. A moving mechanism for moving the first column parallel to the measurement plane;
The moving mechanism is
A guide mechanism for holding the column parallel to the rotation axis of the turntable;
The roundness measuring device according to claim 2, further comprising a feed mechanism that moves the column. A second column extending parallel to the first column and movable in parallel to the measurement plane independently of the first column;
A second fixing portion moving mechanism that movably supports the second holder fixing portion along the second column;
A second detector holder attached to the second holder fixing part;
The roundness measuring device according to claim 2, further comprising: a second detector attached to the second detector holder so that the measuring element can be displaced in the measurement plane. A moving mechanism for moving the first column and the second column parallel to the measurement plane;
The moving mechanism is
A guide mechanism for holding the first column and the second column parallel to the rotation axis of the turntable;
A first feed mechanism for moving the first column;
The roundness measuring device according to claim 4, further comprising: a second feed mechanism that is independent of the first feed mechanism and moves the second column. The two-dimensional movement mechanism is
A column extending parallel to the rotation axis of the turntable;
A moving part supported movably along the column;
The roundness measuring apparatus according to claim 1, further comprising: a fixing part moving mechanism that is attached to the moving part and moves the holder fixing part parallel to the measurement plane.

Images