JP3654744B2 - Roundness measuring machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a roundness measuring machine for measuring the roundness and cylindrical shape of an object to be measured (referred to as “work” in the present specification), and among them, a detector rotating type roundness measuring machine. About.
[0002]
[Prior art]
Roundness measuring machines include a table rotating type that mounts a work on a rotating table provided on the base and moves the detector provided on the column fixed or moved up and down, or a work on a table that does not rotate. There is a detector rotation type that is mounted and measured by rotating or vertically moving the detector. The table rotation type is used for small parts, and the detector rotation type is used for large parts.
[0003]
As shown in FIG. 3, the detector rotation type roundness measuring machine is provided with an XY table 12 supported on a base 11 so as to be movable in the horizontal direction (XY direction), and a column 13 is set up on the base 11. A Z table 15 is supported by a Z guide 14 provided in the column 13 so as to be movable in the vertical direction (Z direction). A rotation support portion is built in the front side of the Z table 15, and a spindle 16 is rotatably supported by the rotation support portion.
A support arm 17 is fixed to the lower end of the spindle 16, and a slide block 18 is supported on the support arm 17 so as to be movable in the horizontal uniaxial direction. A detector holder 18a is fixed to the lower surface of the slide block 18, and a detector 19 is attached to the detector holder 18a.
[0004]
The detector rotation type roundness measuring machine is configured in this way, and with the workpiece W placed and fixed on the XY table 12, the XY table 12 is driven to center the measurement portion of the workpiece. After aligning the rotation center of the detector 19 roughly (within the measurable range of the detector 19), the detector 19 is rotated by the spindle 16 to measure the circumference of the workpiece W, and the roundness is calculated from the measured data. To do.
Further, since the detector 19 can be moved in the Z direction by the Z table 15, it is possible to measure the roundness of an arbitrary position in the Z direction of the workpiece (hereinafter referred to as “measurement section” or simply “section”). This makes it possible to calculate the coaxiality and the cylindrical shape from the roundness data in each measurement section.
[0005]
[Problems to be solved by the invention]
However, when the Z table 15 moves in the Z direction, the horizontal fluctuation occurs due to the movement accuracy of the Z guide 14. As a result, the rotation center of the spindle 16 is displaced with respect to the center of the workpiece measurement portion (hereinafter referred to as “work center”), and the following measurement error occurs.
[0006]
This is shown in FIG. C represents the workpiece center, Ro represents the distance from the rotation center of the spindle 16 to the detector 19, and So represents the distance from the detector 19 to the point where the probe 19a contacts the workpiece.
If the rotation center of the spindle 16 coincides with the workpiece center C, the distance So from the detector 19 to the probe 19a does not change even if the detector 19 rotates, but the rotation center of the spindle 16 does not change from the workpiece center C. When displaced by α, the distance from the detector 19 to the measuring element 19a changes from Sb to Sc. As a result, an error δ expressed by the following equation occurs.
δ = Sc−Sb = 2α
[0007]
If only the roundness of one cross section of the workpiece is simply measured, the error δ is proportional to the rotation circumferential angle of the detector 19, so that correct roundness can be calculated by correction calculation. When the roundness of the cross section is measured to obtain the coaxiality and the cylindrical shape, the error δ becomes a measurement error as it is.
[0008]
The present invention has been made in view of such circumstances, and when the roundness of a plurality of cross sections of a workpiece is measured by a roundness measuring machine of a detector rotation type to obtain the coaxiality, An object of the present invention is to provide a method capable of measuring without being affected by the motion accuracy.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a detector guide 21 on the slide block 18 of a detector-rotating roundness measuring machine, and places the detector 19 along the detector guide 21 in an arbitrary position in the Z direction. Can be set to And when calculating | requiring the concentricity of a workpiece | work, the Z table 15 is not moved but the detector 19 is moved.
In this way, even if the detector 19 is moved to a plurality of measurement sections, the rotation center of the spindle 16 with respect to the workpiece center C is not displaced, and thus the error δ described above does not occur.
[0010]
Embodiment
An overall view of an embodiment of a roundness measuring machine according to the present invention is shown in FIG. 1, a detailed view near a detector is shown in FIG. 2, and a measurement explanatory diagram is shown in FIG.
[0011]
The roundness measuring machine shown in FIG. 1 has the same basic configuration as that described in the prior art (FIG. 3). The difference from the prior art is the structure that supports the detector.
That is, as shown in FIG. 2, the detector guide 21 is fixed to the lower surface of the slide block 18, and the detector holder 22 is supported so as to be movable in the Z direction along the detector guide 21 (the rotation is restricted). ) A detector 19 is attached to the detector holder 22. The detector holder 22 can be fixed at an arbitrary position in the Z direction with a fixing screw 23.
[0012]
The detector rotation type roundness measuring machine according to the present invention is configured in this way, and the workpiece XY table 12 is driven to measure the workpiece while the workpiece W is placed and fixed on the XY table 12. After the center of the portion is approximately aligned with the rotation center of the detector 19 (within the measurable range of the detector 19), the detector 19 is rotated by the spindle 16 to measure the circumference of the workpiece W. Calculate the circularity. Up to this point, the method is the same as that described in the prior art.
[0013]
The difference from the conventional technique is a case where another cross section is measured. In the present invention, the Z table 15 is fixed as it is, and the detector holder 22 is moved in the Z direction.
As a result, when the detector holder 22 is moved in the Z direction, the horizontal position of the detector 19 is displaced due to the movement accuracy of the detector guide 21, but the Z table 15 is not moved in the horizontal direction and the center of rotation of the spindle 16 is displaced. Therefore, the error δ as in the conventional technique does not occur.
[0014]
That is, as shown in FIG. 4, even if the distance from the work center C to the detector 19 changes from Ro to Ra and thus the distance from the detector 19 to the probe 19a changes from So to Sa, the spindle 16 Since the center of rotation always coincides with the workpiece center C, the distance from the detector 19 to the probe 19a is the same at any circumferential angle in the same cross section. Therefore, no error occurs.
[0015]
Although the embodiment is an example in which the position of the detector holder 22 is manually moved, this is automatically driven using a feed screw mechanism, a rack and pinion mechanism, a roller transmission mechanism, an air actuator mechanism, and the like. If configured to do so, automatic measurement is also possible.
[0016]
【The invention's effect】
As described above, according to the present invention, the detector guide 21 is provided in the horizontally movable slide block 18 that supports the detector 19 in the detector rotation type roundness measuring machine, and the detector 19 is detected. It can be set at any position in the Z direction along the vessel guide 21. And when measuring the roundness of several cross sections of a workpiece | work and calculating | requiring a coaxial degree, the Z table 15 did not move but the detector 19 was moved. Therefore, since the Z table 15 does not fluctuate in the horizontal direction and the rotation center of the spindle 16 is always located at the work center C, measurement can be performed without being affected by the motion accuracy of the Z guide 14.
[Brief description of the drawings]
1 is an external view of an embodiment of a roundness measuring apparatus according to the present invention. FIG. 2 is a detailed view of a detector portion of FIG. 1. FIG. 3 is an external view of a conventional roundness measuring apparatus. ] Measurement explanatory diagram of the embodiment of the roundness measuring machine according to the present invention [FIG. 5] Measurement explanatory diagram of a conventional roundness measuring machine [Explanation of symbols]
W ... Work 11 ... Base 12 ... XY table 13 ... Column 14 ... Z guide 15 ... Z table 16 ... Spindle 17 ... Support arm 18 ... Slide block 19 ... Detector 19a ... Measurement Child 21 …… Detector guide 22 …… Detector holder

Claims (1)

An XY table supported by a base so as to be horizontally movable;
A Z table supported on the Z guide provided on the column erected on the base so as to be movable in the vertical direction;
A spindle rotatably supported on a rotation support part built in the Z table;
A slide block supported by a support arm fixed to a lower end of the spindle so as to be movable in a horizontal uniaxial direction;
A detector guide provided in a vertical direction on the slide block;
A detector supported by the detector guide in a vertically movable manner;
Consisting of
A roundness measuring machine characterized in that, when the roundness of a plurality of cross sections of a workpiece is measured to determine the coaxiality, the Z table does not move but the detector moves in the vertical direction.

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