JPH087062B2 - Flatness measuring device - Google Patents

Description

Description: [Object of the invention] (Industrial field of application) The present invention relates to a measuring device capable of accurately and reliably measuring the flatness of a flat surface of an object to be measured, and in particular, the installation state of the measuring device. The present invention relates to a flatness measuring device capable of accurately measuring a flatness.

(Prior Art) For example, since a hypoid gear used in a power transmission device of an automobile is used under a high load, it is necessary to machine it with sufficient finishing accuracy when machining it. Since the rear surface is used in a state of being assembled with other parts, it is necessary to secure the flatness of the rear surface in order to improve reliability.

As a method of measuring the flatness of a work that requires such highly precise flatness, first select the three positions that are the most convex on the surface to be measured, and set the heights of these three positions on the same plane. The method of measuring the dimensions of the recess after the installation is adopted. The difference between the maximum value of the convex portion and the minimum value of the concave portion is defined as flatness (μm).

19 to 21 are configuration diagrams showing an example of a conventional flatness measuring method and measuring apparatus, which will be described using a hypoid gear as an object to be measured.

First, as shown in FIG. 19, after applying Komeitan to the back surface 2 of the hypoid gear 1, the back surface 2 of the hypoid gear 1 and the surface plate 3 are slid, and the three most prominent points of the back surface 2 are visually selected. To do. Here, as a result of sliding the back surface 2 of the hypoid gear 1 and the surface plate 3 together, the three most prominent points on the back surface 2 are in direct contact with each other as shown in FIG. Since the exposed portion is exposed, the measurer can sensually select the three convex portions 5 (marked with X in the figure).

Then, as shown in FIG. 21, jack 6 on the surface plate 3.
The hypoid gear 1 is installed on the auxiliary surface plate 7 installed via the, and the three jacks 6 are adjusted using the dial gauge 8 attached to the height gauge 9 so that the heights of the convex portions 5 are the same at three positions. To do. Then, in this state, the entire surface of the back surface is scanned by the dial gauge 8 to measure the depth of the lowest concave portion, and the difference between the height of the convex portion 5 and the height of the concave portion is obtained by calculation. It was decided to be flatness.

(Problems to be Solved by the Invention) However, in the conventional flatness measurement, the flatness is determined by selecting the three convex portions 5, but the accurate positions of these three positions are determined by the individual of the measurer. There was an uncertain factor such as an error caused by the difference, and it was not suitable for the flatness measurement requiring an accuracy of several tens of μm.

Further, there is also a drawback that a lot of measurement time is required for preliminary work such as sliding of a hypoid carrier and flatness measurement.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a flatoid gear flatness measuring apparatus capable of accurately and reliably measuring the flatness of the back surface of a hypoid gear. To do.

[Means for Solving the Problems] (Means for Solving the Problems) The present invention for achieving the above object includes a turntable on which an object to be measured having a substantially circular measurement surface is mounted and rotated, and a turntable of the turntable. Position detection means for detecting a rotational position, a displacement sensor mounted on the turntable, which faces the measurement surface of the object to be measured, and which detects a gap dimension between the measurement surface, and the displacement sensor which passes through the rotation center of the measurement surface. The moving means for moving from one end to the other end on the straight line, and the detection signals of the displacement sensor and the position detecting means calculate an average value of two gap sizes at the same position, and Based on the average value data, the virtual reference plane is determined so that the displacements of the most protruding positions in the circumferential trisection area on the measurement surface are equal to each other, and the flatness calculation processing is performed. A flatness measuring apparatus characterized by comprising a means.

(Operation) In the present invention thus configured, the displacement sensor measures the displacement data at the measurement point on the straight line passing through the center of rotation of the measurement surface while confirming the measurement point by the position detecting means, and Store the data in the computing means.

Next, the average value of the two gap size data at the same measurement point is calculated, and this is used as the corrected gap size data, and this value is used to determine the most prominent position in the circumferential trisection region of the measurement surface. In order to equalize the displacements, the displacement data is rotationally moved by the homogenous conversion to perform the arithmetic processing for determining the virtual reference plane.

Then, the flatness is calculated from the difference between the maximum displacement and the minimum displacement in the entire area.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an entire flatness measuring apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIGS. 3 (A) and (B) are Sectional drawing which shows the modification of an adapter, FIGS. 4-12 are sectional drawings explaining the procedure which corrects the parallelism of a revolving arm, FIG. 13 is the flowchart which shows the operating procedure of the same Example, FIGS. FIG. 18 is a conceptual diagram for explaining the operation principle of the same embodiment, and FIG. 18 is a plan view showing another application example of the present invention.

In addition, although the present embodiment will be described by using a hypoid gear that requires high-precision flatness as the DUT, the flatness measuring device of the present invention is not limited to this hypoid gear, and various DUTs are measured. Can be used.

First, as shown in FIGS. 1 and 2, the flatness measuring apparatus 10 of the present embodiment includes a rear surface 2 of a hypoid gear 1 which is an object to be measured.
As a measurement surface, a turntable 11 for rotating the DUT 1 at a predetermined speed is provided. This hypoid gear 1 has a protrusion formed on the upper surface of the turntable 11.
Fit the through hole 14a of the adapter 14 into the 11a, and
Is installed on the upper surface of the turntable by fitting it into the concave portion 1a of the hypoid gear 1, so that the axis of the hypoid gear 1 and the axis of the turntable 11 coincide with each other.

Here, the shape of the hypoid gear 1 to be measured,
Particularly, when the concave portion 1a has a plurality of shapes, as shown in FIGS. 3 (A) and (B), the shape of the adapter 14 is formed so as to correspond to the shape of each hypoid gear 1, while each of these adapters is formed. It is desirable to form 14 through holes in a shape corresponding to the convex shape of the turntable 11.

As a result, even if there are multiple types of hypoid gears 1 to be measured, these multiple types of hypoid gears 1 can be combined into one turntable by simply preparing each dedicated adapter.
It becomes possible to measure at 11. For example, FIG. 3 (A)
The two hypoid gears 1 shown in (B) are recessed, respectively.
Although the shape of 1a is different, the shape of the stepped portion 14b of the adapter 14 is formed so as to correspond to the shape of these concave portions 1a, and the through hole 14a of the adapter 14 is formed in the convex portion 11a of the turntable 11. Since it corresponds to the shape, after measuring one hypoid gear and then measuring the other hypoid gear, the hypoid gear 1 can be measured by the same measuring device 10 simply by replacing the adapter 14. You can

The moving means 20 includes a swing arm 21 that swings around a support shaft 24.
Further, it has a lateral arm 22 which is orthogonal to the swivel arm 21 and linearly moves along the swivel arm 21, and a displacement sensor 23 is fixed to an end of the lateral arm 22.

This swivel arm 21 turns the DUT 1 into a turntable 11
When installed above, the displacement sensor 23 swivels to the retracted position to prevent interference between the DUT 1 and the measurement position where the displacement sensor 23 faces the measurement surface 2 (center of the back surface) during measurement. (On a straight line passing through) is fixed by turning to. The lateral arm 22 of the present embodiment is capable of reciprocating in a region from one end to the other end of the object to be measured on the revolving arm 21 via the ball screw 31 and the like by the servo motor 30 and the like. That is, on the straight line passing through the center of the hypoid gear 1 shown in FIG. 1, the gap dimension G of the region from the left end to the right end
Can be scanned. Further, at the time of measurement, a command signal is transmitted from a control means (not shown) so as to move the turntable 11 by a predetermined pitch in association with the rotating state of the turntable 11.

The amount of movement of each of the turntable 11 and the moving means 20 is configured to be detected by the position detecting means 32, whereby the current position of the displacement sensor 23 with respect to the measurement surface 2 of the hypoid gear 1 can be grasped. . Then, this detection signal is stored in the storage unit of the calculating means 25 as a displacement sensor.
It is stored in a state corresponding to the measurement data of the gap dimension G by 23.

As described above, the displacement sensor 23, which detects the gap dimension G between the hypoid gear 1 and the measurement surface 2 with high accuracy, is attached to the swivel arm 21 of the moving means 20 while the measurement surface 2 is being attached.
A magnetic sensor or the like can be used as the displacement sensor 23, and the magnetic amount of the magnet circuit varies depending on the gap dimension G between the measurement surface 2 of the hypoid gear 1 and the displacement sensor 23. Is used to detect the gap dimension G. The magnetic quantity detected by the displacement sensor 23 is converted into an electric quantity and then stored in the storage unit of the calculating means 25 as described above.
The data of the gap dimension G stored in the storage unit is further subjected to a calculation process described later to determine the flatness of the measurement surface 2 of the hypoid gear 1.

Further, the calculation means 25 is connected to a display means 26 for displaying the measurement result calculated by the calculation means. The display means 26 may be one in which a certain reference value is input in advance, and whether the measurement result satisfies the reference value is displayed as pass or fail. The measurement data may be separately displayed. In this case, the values of the measurement data are set in various ranges, for example, "red" when the measurement value with respect to the reference surface is 0 to 10 µm, "orange" when the measurement value is 10 to 20 µm, and 20 to 30
When it is μm, it can be displayed in color on the CRT display like “yellow”.

Next, the measurement procedure and the arithmetic processing method of the flatness measuring apparatus of the present embodiment configured as described above will be described with reference to FIGS.
It will be described with reference to FIG.

Measurement procedure First, after the hypoid gear 1 to be measured is installed on the turntable 11 via the adapter 14, the swivel arm 21 of the moving means 20 is swung to the measurement position, and the displacement sensor 23 causes the measurement surface 2 of the hypoid gear 1 to move. The turning arm 21 is fixed so as to be positioned at one end (the left end in FIG. 1) on a straight line passing through the center.

Then, turntable 11 is rotated and displacement sensor 23
The position detecting means 32 detects the gap size G at each position for one revolution of the hypoid gear 1 and inputs the detection signal to the calculating means 25. When the measurement for one round is completed, the moving means 20 is then driven to move the displacement sensor 23 inward in the radial direction by a predetermined pitch, and the turntable is again turned on.
11 is rotated to measure the gap size G for the next one rotation, and this measurement data is input to the calculating means 25. By repeating such an operation, the gap dimension G over the entire area from the outermost circumference to the innermost circumference of the measurement surface 2 of the hypoid gear 1 is input to the calculating means 25.

Further, when the measurement of the gap dimension G over the entire area from the outermost circumference to the innermost circumference is completed in this way, this time, from this innermost circumference to the other end of the hypoid gear 1 (the right end in FIG. 1).
The gap size up to the outermost circumference is measured by the above-mentioned procedure and input to the calculation means.

In the present embodiment, the gap size of the entire region from one end to the other end of the hypoid gear is configured to be measured when the movement locus of the displacement sensor 23 is not parallel to the rotation surface of the turntable 11. For example, as shown in FIG. 4, the turning arm 21 forms an angle α with the turntable 11.
This is because the general plane of the measurement surface to be originally measured is stored in the calculation means 25 as an erroneous plane shape in the measurement data, and the flatness is calculated based on this. It is intended to correct by a simple method without using the master for adjustment. Although this point will be described later, it can be said that the feature of the present invention is that the measurement can be performed without any adjustment by the master and regardless of the parallelism of the turning arm 21.

Calculation Processing Method First, the parallelism between the movement locus of the displacement sensor 23 and the rotation plane of the turntable 11 is corrected.

This is based on the principle described below. That is, as shown in FIG. 4, assuming that the revolving arm 21 is inclined by an angle θ with respect to the rotation surface of the turntable 11, the displacement sensor 23 starts measurement from the outermost peripheral position X of the back surface 2, and When the inner peripheral position Y is reached, the measured data at this time is measured as the hapoid gear 1 whose central portion is recessed at an angle θ as shown in FIG. On the other hand, when the displacement sensor 23 further moves from the innermost peripheral position Y to reach the outermost peripheral position Z at the other end, the measurement data at this time shows that the central portion has an angle θ as shown in FIG. Hypoid gear 1
Will be measured as. Therefore, originally the 4th
As shown in the figure, even if the measurement surface 2 has a substantially flat shape, an accurate measurement surface 2 cannot be obtained depending on the tilted state of the swivel arm 21 or the scanning range of the displacement sensor 23.
If it is configured to pass from the outermost peripheral position X to the center (rotation center) of the measurement surface and measure to the outermost peripheral position Z at the other end as in the present embodiment, on the left and right of the rotation center of the measurement surface 2, The same point is measured once, and the data of the measurement surface 2 can be obtained accurately by averaging the data measured twice.

Also, as shown in FIG. 7, the back surface 2 of the hypoid gear 1
The center part of the
Is inclined with respect to the rotation surface of the turntable 11 by an angle θ, the displacement sensor 23 moves the outermost position X on the rear surface 2.
When the measurement is started from and the innermost position Y is reached, the measurement data at this time is that it was measured as the hapoid gear 1 in which the central portion is convex from the original surface by the angle θ as shown in FIG. Becomes On the other hand, when the displacement sensor 23 further moves from the innermost peripheral position Y to reach the outermost peripheral position Z at the other end, the measured data at this time is such that the central portion is the original surface as shown in FIG. The measurement was made as the hypoid gear 1 recessed by an angle θ.

Similarly, as shown in FIG. 10, when the central portion of the rear surface 2 of the hypoid gear 1 is originally concave and the revolving arm 21 is inclined by an angle θ with respect to the rotation surface of the turntable 11. When the displacement sensor 23 starts the measurement from the outermost peripheral position X of the rear surface 2 and reaches the innermost peripheral position Y, the measured data at this time shows that the central portion is at an angle from the original surface as shown in FIG. This means that the measurement was made as the Hapodoid gear 1 recessed by θ. On the other hand, when the displacement sensor 23 further moves from the innermost peripheral position Y and reaches the outermost peripheral position Z at the other end, the measured data at this time shows that the central portion is the original one as shown in FIG. The measurement was made as the hypoid gear 1 which is convex from the surface by the angle θ.

As described above, in the present embodiment, the gap data G measured by the displacement sensor 23 is separately stored in the calculating means 25 in the range of X to Y and Y to Z, and the position data of the same point is obtained. The two gap size data G are searched and averaged to obtain corrected gap size data G.

Next, the flatness of the back surface 2 of the hypoid gear 1 is calculated from the gap size data G corrected in this way. This calculation process is performed by the flowchart shown in FIG. 13 and the procedure described below.

Conventionally, Komeitan was applied to the object to be measured, and this was rubbed on a surface plate, and the three points of contact were determined by the operator's judgment. In the present embodiment, these three points were determined. Is calculated by the following calculation procedure, and at the same time, the flatness measurement result is also calculated.

Steps 1 to 3 First, as shown in FIG.
On a straight line in the radial direction that forms 120 ° (the circumference is divided into three equal parts), the points having the largest gap size G are extracted from the storage unit of the computing means 25, and the Z axis of these three points α, β, γ. Rotate along with all displacement data so that the displacements in the directions become equal. The X axis, the Y axis, and the Z axis are orthogonal coordinates on the turntable 11.

This rotational movement starts with three points α, as shown in FIG.
Normal vector orthogonal to the plane containing β and γ And the coordinates of the three points α, β, γ with respect to the origin are α (X _α , Y _α , Z _α ), β (X _β , Y _β , Z _β ), γ (X _γ , Y _γ , Z _γ ), Vx = (yβ-yα) (zγ-zα)-(Zβ-Zα) (Yγ-Yα) Vy = (Zβ-Zα) (Xγ-Xα)-(Xβ-Xα) (Zγ-Zα) Vz = (Xβ -Xα) (Yγ-Yα)-(Yβ-Yα) (Xγ-Xα) | V | = (Vx ² + Vy ² Vz ² ) ^1/2 .

Next, the normal line However, as shown in FIG. 17, when the homogeneous transformation equation T that is parallel to the Z axis is obtained, the homogeneous transformation equation T Here, θ _x = Sin ⁻¹ (−v _x ) θ _y = tan ⁻¹ (v _y / v _z ) Thus, with respect to all displacement data, the product with the homogeneous conversion formula , Β, and γ are rotationally moved so that the displacement data are the same in the Z-axis direction.

Steps 4 to 5 Next, as shown in FIG. 16, in the state in which this rotational movement has been completed, the most prominent positions in the regions divided into three equal parts in the circumferential direction are scanned and extracted, and these new positions are extracted. The rotational movement processing of the displacement data is repeated until the displacement data at the three points α ₁ , β ₁ , and γ ₁ become substantially equal. Then, the displacement data at these three new points α, β, and γ are
A plane including the displacement data α _n , β _n , and γ _{n when} they are _equal to each other becomes a virtual reference plane. With this virtual reference plane as a reference,
The flatness of the measurement surface is calculated from the difference between the maximum displacement and the minimum displacement of the displacement data.

As described above, according to the present embodiment, accurate flatness can be measured by a simple operation regardless of the parallelism of the swivel arm and without adjusting by using the master. Further, since the reference position can be determined without including the subjective element of the measurer, the measurement can be performed accurately and with high reliability. Further, no special work is required for the flatness measurement, and the measurement time can be remarkably shortened.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be considered.

For example, as shown in FIG. 18, it is possible to divide the measurement surface into several areas and measure the flatness in each area. In this case, the measurement surface 2 of the hypoid carrier 1 is divided into three concentric regions 27, 28, 29, the maximum displacement and the minimum displacement are measured, and the flatness is calculated from the difference between the two regions, so that each area 27 , 28 and 29 are obtained. Therefore, it is possible to obtain the flatness of each of the divided areas instead of the entire area of the measurement surface 2 in more detail and accurately.

Further, when the measurement surface of the hypoid gear is provided with a bolt hole, it is possible to exclude the displacement data in the vicinity of the bolt hole and perform the above-described calculation process to calculate the flatness.

(Effects of the Invention) As described above, according to the present invention, accurate flatness can be measured by a simple operation, regardless of the parallelism of the swivel arm and without adjusting using the master. .

Further, since the reference position can be determined without including the subjective element of the measurer, the measurement can be performed accurately and with high reliability.

Furthermore, no special work is required for measuring the flatness, so that the measuring time can be significantly shortened.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an entire flatness measuring apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIGS. 3 (A) and (B) are Sectional drawing which shows the modification of an adapter, FIGS. 4-12 are sectional drawings explaining the procedure which corrects the parallelism of a revolving arm, FIG. 13 is the flowchart which shows the operating procedure of the same Example, FIGS. FIG. 18 is a conceptual diagram for explaining the calculation principle of the same embodiment, FIG. 18 is a plan view showing another application example of the present invention, and FIGS. 19 to 21 are explanatory views showing a conventional flatness measuring device. 1 ... Object to be measured, 2 ... Measuring surface, 10 ... Flatness measuring device, 11 ... Turntable, 20 ...
Moving means, 23 ... Displacement sensor, 25 ... Computing means, 26 ... Displaying means, 32 ... Position detecting means.

Claims (1)

[Claims] 1. A turntable for mounting and rotating an object to be measured having a substantially circular measuring surface, position detecting means for detecting a rotational position of the turntable, and an object to be measured mounted on the turntable. A displacement sensor that opposes the measurement surface and that detects a gap dimension between the measurement surface, and a moving unit that moves the displacement sensor from one end to the other end on a straight line that passes through the center of rotation of the measurement surface, An average value of two gap sizes at the same position is calculated by the detection signals of the displacement sensor and the position detecting means, and based on the average value data, a circumferential trisecting region on the measuring surface is calculated. In the flatness measuring apparatus, a virtual reference plane is determined so that the displacements at the most projecting positions in are equal to each other, and the flatness is calculated.