JP6849970B2 - Shaft member shape measurement method and shape measurement device - Google Patents

Description

The present invention relates to a method for measuring the shape of a shaft member and a shape measuring device.

Conventionally, for example, in a long shaft member having a circle having an incomplete radial cross section as exemplified by a rack shaft of a steering device, distortion (deformation) is likely to occur in the axial direction due to its shape. Therefore, work for removing the generated distortion may be required. However, in order to remove the strain, it is first necessary to accurately grasp the state of the strain actually occurring. On the other hand, conventionally, there is a method of detecting distortion (deformation) by using a known differential transformer type displacement type which is one of the contact type sensors.

Specifically, using the differential transformer type displacement type, first, the outer shape of the long shaft portion and the short shaft portion with less distortion is measured while rotating the rack axis around the axis. Then, the control unit estimates the ideal axis position between the long axis portion and the short axis portion from the measurement results of the outer shapes of the long axis portion and the short axis portion. Similarly, the arc shape of the arc shape portion of the rack tooth forming portion formed by a circle having an incomplete radial cross section is measured by the differential transformer type displacement type. Then, the axis position of the arc-shaped portion is estimated from the measurement result, the difference between the estimated axis position of the arc-shaped portion and the above-mentioned ideal axis position is calculated, and the calculated difference is the strain amount of the rack tooth forming portion ( Deformation amount).

Japanese Unexamined Patent Publication No. 5-123753

However, as described above, the arcuate portion is not a perfect circle in its radial cross-sectional shape, but is formed by a part of a circle. Therefore, there is a limit to the accuracy of detecting the axial position of the arc-shaped portion using the differential transformer type displacement type. Further, in recent years, the shape of the teeth of the rack tooth forming portion has become complicated, and in order to cope with this, the rack tooth forming portion may be formed by forging. In this case, surplus meat is generated on both sides of the rack tooth in the forged rack shaft material in a direction parallel to the tooth muscle of the rack tooth and outward. Therefore, for example, the surplus meat is removed by milling. .. As a result, a part of the arc-shaped portion formed by the arc is further removed, so that the size of the arc is further reduced, and the detection accuracy of the axial position by the differential transformer type displacement type is further lowered. There is also a technique disclosed in Patent Document 1 as another example of strain removal of a rack shaft using a differential transformer type displacement type. The technique disclosed in Patent Document 1 also has a similar problem.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a shape measuring method and a shape measuring device for a shaft member capable of accurately measuring strain regardless of the shape of the shaft member. To do.

(1. Method of measuring the shape of the shaft member)
The method for measuring the shape of a shaft member according to the present invention is formed in a first shaft portion having a reference outer peripheral surface having a circular radial cross section and an arc shape having a radial cross section having the same diameter as the reference outer peripheral surface. This is a method for measuring the shape of a shaft member including a second shaft portion having an outer peripheral surface to be measured. The shape measuring method includes a first step of measuring the positions of a plurality of reference points located in a predetermined phase on the reference outer peripheral surface and having different axial positions by a contact type or non-contact type first sensor, and a contact type or non-contact type. The second step of measuring the position of the target point located in the same phase as the predetermined phase on the outer peripheral surface of the measurement by the contact type second sensor, and the plurality of reference points in the radial cross section including the target point. A third step of calculating the corresponding ideal target point and calculating the displacement amount of the measured outer peripheral surface with respect to the reference outer peripheral surface by comparing the ideal target point with the target point is provided.

As described above, in the present invention, a plurality of reference points having different axial positions in a predetermined phase in the circumferential direction on the reference outer peripheral surface (first axis portion) are actually measured, and the measured reference points are covered from the measured reference points. The position of the ideal target point on the outer peripheral surface (second axis) of the measurement is calculated and estimated. In addition, the position of the target point on the outer peripheral surface to be measured, which is located in the same phase as the predetermined phase of the reference point, is measured. Then, the position of the target point is compared with the position of the ideal target point to obtain the difference between the reference outer peripheral surface and the measured outer peripheral surface in the same phase, that is, the amount of displacement of the measured outer peripheral surface with respect to the reference outer peripheral surface. .. As a result, unlike the prior art, the displacement amount (strain amount) of the second shaft portion can be accurately measured even if the outer peripheral surface of the second shaft portion to be measured does not have a large arc.

(2. Shaft member shape measuring device)
The shaft member shape measuring device according to the present invention is formed into a first shaft portion having a reference outer peripheral surface having a circular radial cross section and an arc shape having a radial cross section having the same diameter as the reference outer peripheral surface. A second shaft portion having an outer peripheral surface to be measured is provided. The shape measuring device includes a contact type or non-contact type first sensor that measures the positions of a plurality of reference points that are located in a predetermined phase on the reference outer peripheral surface and have different axial positions, and the predetermined phase on the measured outer peripheral surface. A contact-type or non-contact-type second sensor that measures the position of the target point located in the same phase as the target point, and an ideal target point corresponding to the plurality of reference points in the radial cross section including the target point are calculated and described. A control unit for calculating the amount of displacement of the outer peripheral surface to be measured with respect to the reference outer peripheral surface by comparing the ideal target point with the target point is provided. As a result, by the measurement by the shape measuring device of the shaft member, even if the outer peripheral surface to be measured has a shape that does not have many arcs, the outer peripheral surface to be measured with respect to the reference outer peripheral surface is the same as the above-mentioned method for measuring the shape of the shaft member. The amount of displacement (amount of strain) can be detected accurately.

It is a side view of the rack shaft which concerns on this embodiment. It is a top view of the rack shaft which concerns on this embodiment. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 6 is a cross-sectional view taken along the line IV-IV in FIG. It is a schematic diagram seen from the axial direction of the rack shaft explaining the state which the rack tooth forming part (second shaft part) and the long shaft part (first shaft part) are relative displacement. It is a schematic diagram of a shape measuring apparatus. It is explanatory drawing of the state of measuring the position of the reference point of the reference outer peripheral surface by the 1st sensor. It is explanatory drawing of the state of measuring the position of the target point of the outer peripheral surface to be measured by the 2nd sensor. It is a flowchart of a shape measurement method.

<1. First Embodiment>
(1-1. Overview)
Hereinafter, a shape measuring device for measuring the outer peripheral surface shape of the shaft member according to the embodiment of the present invention will be described. In the present embodiment, the shaft member will be described as an example of a rack shaft used in a steering device for automobiles. Therefore, in the following, first, the rack shaft 10 to be measured will be described. Since the rack shaft of the steering device is a known product, detailed description of the functions and the like is omitted except for necessary parts.

(1-2. Rack shaft 10)
As shown in the side view of FIG. 1, the rack shaft 10 has a long shaft portion 12 (corresponding to the first shaft portion) and a rack tooth forming portion 13 (second) in order from the tip (right side in FIG. 1) to the left. It has a shaft portion) and a short shaft portion 14. The rack shaft 10 shown in FIG. 1 is described in a posture when the outer peripheral surface shape is measured by the shape measuring device 20 described later. The long shaft portion 12 (first shaft portion) includes a reference outer peripheral surface 12a which is a reference surface having a circular radial cross section (see FIG. 3). The reference outer peripheral surface 12a is formed over the entire length in the axial direction of the long shaft portion 12 (first shaft portion).

The reference outer peripheral surface 12a is used as a datum surface. Therefore, the reference outer peripheral surface 12a is such that, for example, the contour line in the circumferential direction fits between two ideal cylinders formed with a predetermined interval (range) about the axis line of the long axis portion 12. It is formed. That is, the cylindricity (see JIS B 0621) is formed so as to be within a predetermined range. At this time, the predetermined interval may be set to an arbitrary value in consideration of the shape accuracy required for each product. However, not limited to the above aspect, the reference outer peripheral surface 12a may be set so that the circumferential runout or the total runout (both refer to JIS B 0621) of the reference outer peripheral surface 12a falls within a predetermined range.

FIG. 2 is a top view of the rack shaft 10. The rack shaft 10 is obtained by removing a part (remaining thicknesses 15 and 15) of the rack shaft material 11 shown by the alternate long and short dash line by milling or the like. The surplus thicknesses 15 and 15 are burrs formed so as to project in the direction orthogonal to the axis between the forging dies when the rack tooth forming portions 13 are formed by pressing the upper and lower forging dies.

As shown in the radial cross section of FIG. 4, the rack tooth forming portion 13 (second shaft portion) is formed in an arc shape having the same diameter as the outer diameter (= φD) of the reference outer peripheral surface 12a described above. An outer peripheral surface 13a is provided. As shown in FIGS. 1 and 2, in the present embodiment, the outer peripheral surface 13a to be measured is continuously formed so as to be the same surface as the reference outer peripheral surface 12a. As shown in FIG. 4, the size of the arc of the outer peripheral surface 13a to be measured after the surpluses 15 and 15 are removed is about 140 deg around the axis. In other words, the outer peripheral surface 13a to be measured of the rack tooth forming portion 13 (second shaft portion) is formed in a range of less than 180 degrees around the axis in the circumferential direction.

As shown in FIGS. 1 and 2, the long shaft portion 12 and the short shaft portion 14 are not provided with rack teeth. The long shaft portion 12 is formed to be longer than the short shaft portion 14. In the following, the axial direction means the extension direction of the rack shaft 10, that is, the axial direction of the rack shaft 10.

A plurality of rack teeth 16 are formed on the lower surface (lower side in FIG. 1 and the back side of the paper surface in FIG. 2) of the rack tooth forming portion 13 (second shaft portion) in FIG. The plurality of rack teeth 16 are formed on a portion (corresponding to a non-arc outer peripheral surface) that faces the outer peripheral surface 13a to be measured. As described above, the rack tooth forming portion 13 is an incomplete cylinder having a non-circular outer peripheral surface formed in a non-arc shape different from the arc shape of the outer peripheral surface 13a to be measured in the circumferential direction around the axis.

The plurality of rack teeth 16 are formed by being plastically deformed by, for example, warm forging. The rack teeth 16 of the rack shaft 10 according to the present embodiment are not uniformly formed in the axial direction. That is, each rack tooth 16 is formed and arranged so that the output characteristic of a variable gear ratio (that is, variable gear ratio (VGR)) is output in meshing with the pinion shown in the drawing. A detailed description will be omitted.

(1-2-1. Reference point on the reference outer peripheral surface 12a)
Next, reference points (first to third reference points RP1, RP2, RP3) set on the reference outer peripheral surface 12a of the long shaft portion 12 (first shaft portion) measured by the first sensor 21 described later will be described. .. In explaining the reference point, first, in FIG. 3 showing the radial cross section of the long shaft portion 12 (first shaft portion), the highest point (vertex) position on the reference outer peripheral surface 12a is set to the first predetermined phase Ph1 in the circumferential direction. Is defined as. Further, as shown in FIG. 3, from the first predetermined phase Ph1, the position rotated to the left (corresponding to less than 90 deg) is set to 70 deg in the circumferential direction, and the second predetermined phase Ph2 in the circumferential direction is set to 70 deg in the circumferential direction. The position rotated to the right (corresponding to less than 90 deg) is defined as the third predetermined phase Ph3 in the circumferential direction.

Then, a plurality of points on the reference outer peripheral surface 12a in the first predetermined phase Ph1 are defined as the first reference point RP1. Further, a plurality of points on the reference outer peripheral surface 12a in the second predetermined phase Ph2 are defined as the second reference point RP2, and a plurality of points on the reference outer peripheral surface 12a in the third predetermined phase Ph3 are defined as the third reference point RP3. To do. The first to third reference points RP1, RP2, and RP3 are arbitrary two positions (corresponding to a plurality of points) having different axial positions in the axial direction of the long axis portion 12 (first axis portion), respectively. It is set at P1 and the second position P2 (see FIG. 1). That is, each of the first reference point RP1, the second reference point RP2, and the third reference point RP3 are located at the same position (in-phase) in the axial direction.

The positions (coordinates) of the first to third reference points RP1, RP2, and RP3 set at two points (first position P1, second position P2) in the axial direction are measured by the first sensor 21 described later. To. As will be described in detail later, the first sensor 21 is composed of three sensors.

Not limited to the above embodiment, the first to third reference points RP1, RP2, and RP3 are set at any three or more locations having different axial positions in the axial direction of the long axis portion 12 (first axis portion). You may. As a result, the load on the control unit during the calculation and the time required for the measurement increase, but the position accuracy of the reference outer peripheral surface 12a obtained by the calculation is improved.

Further, in the above, the position where the second predetermined phase Ph2 and the third predetermined phase Ph3 are rotated by 70 deg from the first predetermined phase Ph1 on both sides in the circumferential direction around the axis is the rack tooth forming portion 13 (second). The phase of the end of the arc (140 deg) of the outer peripheral surface 13a to be measured of the shaft portion) is matched. The positions of the second predetermined phase Ph2 and the third predetermined phase Ph3 may be changed to arbitrary other positions within the range of the outer peripheral surface 13a to be measured.

(1-2-2. Target points on the outer peripheral surface to be measured)
Next, a plurality of target points (third) having different axial positions to be measured in the axial direction of the outer peripheral surface 13a to be measured of the rack tooth forming portion 13 (second shaft portion) measured by the second sensor 22 described later. The first to third target points TP1, TP2, TP3) will be described. In the present embodiment, the target points TP1, TP2, and TP3 correspond to the first to third predetermined phases Ph1, Ph2, and Ph3 in the circumferential direction of the outer peripheral surface 13a to be measured, respectively.

On the outer peripheral surface 13a to be measured, a point located in the same phase as the first predetermined phase Ph1 is defined as the first target point TP1 (target point). Further, a point located in the same phase as the second predetermined phase Ph2 is defined as a second target point TP2 (target point). Further, a point located in the same phase as the third predetermined phase Ph3 is defined as a third target point TP3 (target point). In the present embodiment, the first target point TP1, the second target point TP2, and the third target point TP3 are set at six positions (corresponding to a plurality of positions) at different positions in the axial direction of each phase (corresponding to a plurality of positions). (See FIGS. 1 and 2).

In the present embodiment, the measured outer peripheral surface 13a of the rack tooth forming portion 13 (second shaft portion) is relative to the reference outer peripheral surface 12a of the long shaft portion 12 (first shaft portion) as shown in FIG. The explanation will proceed assuming that it is slightly displaced (deformed). At this time, the cause of the displacement does not matter. In FIG. 5, the reference outer peripheral surface 12a of the long shaft portion 12 (first shaft portion) is indicated by a two-dot chain line with respect to the measured outer peripheral surface 13a of the rack tooth forming portion 13 (second shaft portion). In this way, it is assumed that a relative displacement occurs between the outer peripheral surface 13a to be measured and the reference outer peripheral surface 12a.

The positions (coordinates) of the first to third target points TP1, TP2, and TP3 are measured by the second sensor 22, which will be described later. In the present embodiment, the second sensor 22 is composed of three sensors that are exactly the same as the first sensor 21. Then, the positions (coordinates) of the first to third target points TP1, TP2, and TP3 are measured by each of the three sensors. That is, the three sensors measure the positions of the first to third reference points RP1, RP2, RP3 and the first to third target points TP1, TP2, TP3. Details will be described later. However, not limited to the above aspect, the first sensor 21 and the second sensor 22 may be configured by three different sensors.

As described above, the first target point TP1, the second target point TP2, and the third target point TP3 are a plurality of points at different axial positions in the axial direction of the rack tooth forming portion 13 (second shaft portion) in each phase. (Multiple points) Measured. At this time, the plurality of points to be measured may be measured at predetermined distances or at random distances set arbitrarily.

(1-3. Shape measuring device)
Next, the shape measuring device 20 will be described (see FIG. 6). The shape measuring device 20 is used at each position (first to third reference points RP1, RP2, RP3, and first to third) on the reference outer peripheral surface 12a and the outer peripheral surface 13a of the rack shaft 10 (shaft member) described above. (3) Measure the target points (at each position of TP1, TP2, TP3). Then, the shape measuring device 20 calculates the amount of deformation of the measured outer peripheral surface 13a with respect to the reference outer peripheral surface 12a based on the respective positions (coordinates) of the measured reference outer peripheral surface 12a and the measured outer peripheral surface 13a.

As described above, in the shape measuring device 20, the rack shaft 10 (shaft member) is supported with the rack teeth 16 facing downward as shown in FIG. The positions A and B where the rack shaft 10 is supported are arbitrary two points in the axial direction on the reference outer peripheral surface 12a of the long shaft portion 12 (first shaft portion). However, the supported positions are not limited to two points, and may be three or more points. Also, the method of support is not limited. For example, at each support position, the rack shaft 10 may be rotatably supported around the axis by arranging three rollers at equal intervals in the circumferential direction of the reference outer peripheral surface 12a. Further, the rack shaft 10 may be supported around the axis so as not to rotate.

As shown in FIG. 6, the shape measuring device 20 mainly includes a first sensor 21 (second sensor 22), a sensor rail 30, and a control unit 40. In the present embodiment, the first sensor 21 and the second sensor 22 are the same sensor and are shared. As shown in FIGS. 7 and 8, the first sensor 21 (second sensor 22) is a laser sensor 23_Ph1 for the first predetermined phase Ph1, a laser sensor 24_Ph2 for the second predetermined phase Ph2, and a third predetermined phase, respectively. It is composed of three laser sensors called a laser sensor 25_Ph3 for Ph3. The laser sensors 23_Ph1,24_Ph2, 25_Ph3 are similar sensors and are non-contact type sensors.

The laser sensor 23_Ph1,24_Ph2, 25_Ph3 is a known laser sensor, which irradiates a measurement target portion with a laser beam from the laser irradiation surface, and is a distance from the laser irradiation surface to the nearest portion of the measurement target. It is a laser sensor that can measure.

The sensor rail 30 is arranged above the rack shaft 10 in FIG. 6 and parallel to the axis of the rack shaft 10. Each laser sensor 23_Ph1,24_Ph2, 25_Ph3 is provided on the sensor rail 30 so as to be movable along the sensor rail 30. The number of sensor rails 30 may be one, or three so that each laser sensor 23_Ph1,24_Ph2, 25_Ph3 is provided. When there is only one sensor rail 30, the laser sensors 23_Ph1,24_Ph2, 25_Ph3 are integrally configured.

The laser sensor 23_Ph1,24_Ph2, 25_Ph3 is moved in the axial direction on the sensor rail 30 by a desired amount under the control of the control unit 40. Then, as shown in FIG. 7, the laser sensors 23_Ph1,24_Ph2, 25_Ph3 (first sensor 21) are, respectively, in a direction orthogonal to the axis of the rack shaft 10 (shaft member) under the control of the control unit 40, and Each reference point (first to third reference points) in each measurement direction DR1, DR2, DR3 (corresponding to a predetermined measurement direction) in the direction passing through each reference point (first to third reference points RP1, RP2, RP3) Measure the position (coordinates) of RP1 to RP3).

In the above, the laser sensors 23_Ph1,24_Ph2, 25_Ph3 (first sensor 21), the first to third reference points RP1, RP2, RP3 and the measurement directions DR1, DR2, DR3 correspond in order from the youngest number. It shall be. For example, the reference point measured by the laser sensor 23_Ph1 is the first reference point RP1, and the measurement direction in which the laser beam LB1 of the laser sensor 23_Ph1 is irradiated is the measurement direction DR1.

The same applies to the laser sensor 24_Ph2, the reference point measured by the laser sensor 24_Ph2 is the second reference point RP2, and the measurement direction in which the laser beam LB2 of the laser sensor 24_Ph2 is irradiated is the measurement direction DR2. The same applies to the laser sensor 25_Ph3. The same applies to the sensor reference planes E1, E2, E3, the spot diameters φD1, φD2, φD3, and the shortest distances L1, L2, L3, etc., which will be described later.

As shown in FIG. 7, each laser sensor 23_Ph1,24_Ph2, 25_Ph3 (first sensor 21) has a measurement direction from each sensor reference surface E1, E2, E3, which is each laser irradiation surface, under the control of the control unit 40. Each spot diameter φD1, φD2, φD3 (corresponding to a predetermined spot diameter) in the direction of DR1, DR2, DR3 (corresponding to a predetermined measurement direction) and toward the first to third reference points RP1, RP2, RP3. Each laser beam LB1, LB2, LB3 having the above is irradiated.

At this time, the laser beams LB1, LB2, and LB3 are irradiated in a columnar shape from the sensor reference planes E1, E2, and E3 toward the first to third reference points RP1, RP2, and RP3. That is, each laser sensor 23_Ph1,24_Ph2, 25_Ph3 (first sensor 21) has a cross-sectional area of the radial cross section of the cylindrical laser beam LB1, LB2, LB3 irradiated in the direction orthogonal to the measurement directions DR1, DR2, DR3. It is provided with a measurement range (corresponding to a predetermined measurement range) according to the above. In this embodiment, each spot diameter φD1, φD2, φD3 has the same diameter. Therefore, each measurement range has the same area. However, the diameter is not limited to this and does not have to be the same.

From the above, each sensor reference plane E1, E2, E3 is also orthogonal to each measurement direction DR1, DR2, DR3 within each measurement range. Further, the sensor reference planes E1, E2, E3 and the first to third reference points RP1, RP2, RP3 (reference points) are arranged with a predetermined distance.

With such a configuration, the distance between each sensor reference surface E1, E2, E3 and the first to third reference points RP1, RP2, RP3 (reference point) is set to the sensor reference surface E1, E2, E3 and the reference outer circumference. Since the shortest distance L1, L2, L3 can be set with respect to the distance to a point other than the reference point on the surface 12a, the positions (coordinates) of the first to third reference points RP1, RP2, RP3 can be measured.

Further, as shown in FIG. 8, the second sensor 22 (laser sensor 23_Ph1,24_Ph2, 25_Ph3) also has the same operation as that of the first sensor 21, and each target point (first to third target points TP1, TP2). The position (coordinates) of TP3) can be measured. In the second sensor 22 (laser sensor 23_Ph1,24_Ph2, 25_Ph3), the first sensor 21 is read as the second sensor 22 in response to the explanation of the first sensor 21, and each reference point (first to third reference point RP1) is read. , RP2, RP3) may be read as each target point (first to third target points TP1, TP2, TP3), and the reference outer peripheral surface 12a may be read as the measured outer peripheral surface 13a. Others are the same as the description for the first sensor 21.

With such a configuration, the distance between each sensor reference surface E1, E2, E3 and the first to third target points TP1, TP2, TP3 (target points) is set between the sensor reference surfaces E1, E2, E3. Since the shortest distances L4, L5, and L6 can be set with respect to the distance to a point other than the target point on the measurement outer peripheral surface 13a, the positions (coordinates) of the first to third target points TP1, TP2, and TP3 can be measured. It becomes.

From the above, the positions of the first to third reference points RP1, RP2, RP3 and the first to third target points TP1, TP2, TP3 vary or move on the reference outer peripheral surface 12a and the measured outer peripheral surface 13a. Even so, within the predetermined measurement range, the first to third laser beams LB1, LB2, LB3 of each laser sensor 23_Ph1,24_Ph2, 25_Ph3 are reference points (first to third reference points RP1, RP2, The positions of the RP3) and the target points (first to third target points TP1, TP2, TP3) can be reliably detected.

(2. Shaft member shape measurement method)
Next, the method of measuring the shape of the outer peripheral surface 13a to be measured of the rack shaft 10 described above will be described with reference to the flowchart of FIG. The method for measuring the shape of the rack shaft 10 (shaft member) according to the present invention includes a first step (step S10-S18), a second step (step S20-S28), and a third step (step S30-S34). To be equipped.

(2-1. First step)
As described above, in the first step, a non-contact type first sensor 21 (laser sensor 23_Ph1,24_Ph2,25_Ph3) is used to perform a predetermined phase (first to third predetermined phases Ph1,) in the circumferential direction on the reference outer peripheral surface 12a. This is a step of measuring the positions (coordinates) of three reference points (first to third reference points RP1, RP2, RP3) located at Ph2, Ph3) at two points (plurality) having different axial positions.

In step S10 (first step), the laser sensor 23_Ph1,24_Ph2, 25_Ph3 is moved in the axial direction on the sensor rail 30 arranged above the rack shaft 10 (shaft member) under the control of the control unit 40. It reaches the first position P1 on the preset reference outer peripheral surface 12a (first shaft portion). If the laser sensor 23_Ph1,24_Ph2, 25_Ph3 is already located at the first position P1, it moves to the second position P2.

Next, in step S12 (first step), under the control of the control unit 40, the cylindrical laser beams LB1, LB2, LB3 are converted into the sensor reference planes E1, which are the laser irradiation surfaces of the laser sensors 23_Ph1,24_Ph2, 25_Ph3. Irradiation is performed from E2 and E3 toward the first to third reference points RP1, RP2 and RP3 (see FIG. 7). Each laser beam LB1, LB2, LB3 has each spot diameter φD1, φD2, φD3 (φD1 = φD2 = φD3), and is irradiated with each measurement range corresponding to each spot diameter.

Next, in step S14 (first step), the positions (coordinates) of the first to third reference points RP1, RP2, and RP3 are measured. As described above, at this time, the distance between the sensor reference planes E1, E2, E3 and the first to third reference points RP1, RP2, RP3 is the shortest distance L1, L2, L3 (see FIG. 7). Therefore, the positions (coordinates) of the first to third reference points RP1, RP2, and RP3 are measured.

In the above, the position (coordinates) of the first reference point RP1 is a position measured along the vertical direction (measurement direction DR1). The position (coordinates) of the second reference point RP2 is a position measured along the measurement direction DR2. Further, the position (coordinates) of the third reference point RP3 is a position measured along the measurement direction DR3. Then, in step S16 (first step), the measurement result of the position of each reference point is transmitted to the storage unit 41 of the control unit 40.

Next, in step S18 (first step), it is confirmed whether or not the measurement of the positions (coordinates) of the first to third reference points RP1, RP2, and RP3 in step S14 is the second time. If the measurement is the first time, the process proceeds to step S10 according to "N" (No).

In the second step S10, the laser sensor 23_Ph1,24_Ph2, 25_Ph3 is moved in the axial direction on the sensor rail 30 under the control of the control unit 40, and reaches the second position P2 from the first position P1. Then, in steps S12 and S14, the positions (coordinates) of the first to third reference points RP1, RP2, and RP3 at the second position P2 are measured, and in step S16, the measurement result is stored in the storage unit 41 of the control unit 40. Will be sent.

In this way, the laser sensors 23_Ph1,24_Ph2, 25_Ph3 move in the axial direction of the rack shaft 10 (shaft member), and the first to third reference points RP1, RP2, at two locations (plurality) having different axial positions. Measure the position of RP3 (reference point). Then, in the confirmation step of step S18, since the measurement is the second time, the process moves to step S20 (second step) according to “Y” (Yes).

(2-2. Second step)
In the second step, a non-contact type second sensor 22 (laser sensor 23_Ph1,24_Ph2, 25_Ph3) is used to perform a predetermined phase (first to third predetermined phases Ph1, Ph2) on the reference outer peripheral surface 12a on the outer peripheral surface 13a to be measured. This is a step of measuring the positions of the first to third target points TP1, TP2, and TP3 (target points) located in the same phase as Ph3). The second sensor 22 is shared with the first sensor 21. In the second step, the laser sensor 23_Ph1,24_Ph2, 25_Ph3 (second sensor 22) moves in the axial direction of the rack shaft 10 (shaft member), and at the same time, a plurality of target points having different axial positions on the outer peripheral surface 13a to be measured. Measure the position of.

In step S20 (second step), the laser sensor 23_Ph1,24_Ph2, 25_Ph3 is moved in the axial direction on the sensor rail 30 under the control of the control unit 40, and the preset rack tooth forming unit 13 (second shaft unit) is moved. ) Moves to an arbitrary position P3 (see FIG. 6) on the outer peripheral surface 13a to be measured.

Next, as in step S12, in step S22 (second step), the laser sensor 23_Ph1,24_Ph2, 25_Ph3 is a sensor whose cylindrical laser light LB1, LB2, LB3 is the laser irradiation surface under the control of the control unit 40. Irradiation is performed from the reference surfaces E1, E2, E3 toward the first to third target points TP1, TP2, TP3 (target points) on the outer peripheral surface 13a to be measured. Each laser beam LB1, LB2, LB3 has each spot diameter φD1, φD2, φD3 (φD1 = φD2 = φD3), and is irradiated with each measurement range corresponding to each spot diameter.

At this time, the optical axes of the laser beams LB1, LB2, and LB3 are parallel to the measurement directions DR1, DR2, and DR3, respectively. Further, the sensor reference planes E1, E2, and E3 are orthogonal to the measurement directions DR1, DR2, and DR3. As a result, in step S24 (second step), the shortest distances between the sensor reference planes E1, E2, and E3 are L4, L5, and L6 (see FIG. 8). The position (coordinates) is measured.

In the above, the position (coordinates) of the first target point TP1 is a position measured along the vertical direction (measurement direction DR1). The position (coordinates) of the second target point TP2 is a position measured along the measurement direction DR2. Further, the position (coordinates) of the third target point TP3 is a position measured along the measurement direction DR3. Then, in step S26 (second step), the position data (measurement result) of each target point is transmitted to the storage unit 41 of the control unit 40.

Next, in step S28 (second step), it is confirmed whether or not the measurement of the positions (coordinates) of the first to third target points TP1, TP2, and TP3 in step S24 has reached the preset Nth time. .. If the number of measurements has not reached N times, the process proceeds to step S20 according to "N" (No).

Then, in the second and subsequent steps S20 (second step), the laser sensor 23_Ph1,24_Ph2, 25_Ph3 is moved in the axial direction on the sensor rail 30 under the control of the control unit 40, and a preset rack tooth forming unit is formed. It moves to an arbitrary position P4 (see FIG. 6) on the outer peripheral surface 13a to be measured of 13 (second shaft portion). Then, the positions (coordinates) of the first to third target points TP1, TP2, and TP3 at the arbitrary position P4 are measured by the processing of step S20-step S24, and the position data (measurement result) is obtained by the control unit 40 in step S26. Is transmitted to the storage unit 41 of.

Then, in step S28, the process of step S20-step S28 is repeated until it is confirmed that the measurement in step S24 has been performed N times (six times in this embodiment) preset. When it is confirmed that the measurement has been performed N times in step S28, the process proceeds to step S30 (third step) according to “Y” (Yes). The number of measurements (N times), which is the determination criterion, may be arbitrarily set.

As described above, in the second step, the laser sensors 23_Ph1,24_Ph2, 25_Ph3 move in the axial direction of the rack shaft 10 (shaft member), and the first to third target points TP1, TP2, TP3 (target points) at a plurality of locations. ) Is measured.

(2-3. Third step)
In step S30 (third step), the control unit 40 has two (plurality) parts stored in the storage unit 41 in the radial cross section including the first to third target points TP1, TP2, TP3 (target points). The position data of the first to third reference points RP1, RP2, and RP3 (reference points) of the above are taken out. Then, based on the position data extracted in step S32 (third step), the first to third ideal target points ITP1, ITP2, ITP3 (ideal targets) corresponding to the first to third reference points RP1, RP2, and RP3, respectively. Point) is calculated.

Specifically, the outer peripheral surface shape calculated based on the first to third reference point RP1, RP2, RP3 (reference point) data in the reference outer peripheral surface 12a for two locations (plurality) is set as the ideal outer peripheral surface shape. Then, the calculated ideal outer peripheral surface shape is extended to a virtual radial cross section including the first to third target points TP1, TP2, TP3 (target points) for each axial position, and the intersecting points are set to the third. It is calculated as virtual first to third ideal target points ITP1, ITP2, ITP3 (ideal target points) corresponding to the first to third reference points RP1, RP2, and RP3 (see FIG. 8). In FIG. 8, the positions of the first to third reference points RP1, RP2, RP3 (reference points) and the positions of the first to third ideal target points ITP1, ITP2, ITP3 (ideal target points) coincide with each other. ing.

Then, in step S34 (third step), the position data of the first to third target points TP1, TP2, TP3 stored in the storage unit 41 is taken out, and the first to third ideal target points ITP1, ITP2, ITP3 are obtained. The first to third target points TP1, TP2, and TP3 (target points) are compared (see FIG. 8). As a result, the displacement amount (first to third displacement amounts Q1, Q2, Q3) of the measured outer peripheral surface 13a with respect to the reference outer peripheral surface 12a in each phase (first to third predetermined phases Ph1, Ph2, Ph3) is calculated. To do.

The first to third displacement amounts Q1, Q2, and Q3 are displacement amounts related to the first to third target points TP1, TP2, and TP3 (target points). Therefore, with this displacement amount (first to third displacement amounts Q1, Q2, Q3), the rack tooth forming portion 13 (second shaft portion) is displaced with respect to the reference outer peripheral surface 12a (first shaft portion). To do. As a result, it is possible to perform highly accurate strain removing work on the rack shaft 10 based on the calculated first to third displacement amounts Q1, Q2, and Q3.

(3. Others)
In the above embodiment, the phase (Ph1, Ph2, Ph3) for calculating the reference point (RP1, RP2, RP3), the target point (TP1, TP2, TP3) and the ideal target point (ITP1, ITP2, ITP3) Was set within the range of 140 deg in the circumferential direction of the rack shaft 10 (shaft member). However, the present invention is not limited to this mode, and the number of phases may be two. That is, the reference point (RP1, RP2), the target point (TP1, TP2), and the ideal target point (ITP1, ITP2) may be calculated according to the two phases. In this case, the angle formed by the two phases is preferably about 90 deg. This also has a corresponding effect.

Further, in the above embodiment, the size of the arc of the outer peripheral surface 13a to be measured in the rack tooth forming portion 13 (second shaft portion) is set to the range of 140 deg in the circumferential direction, but the present invention is not limited to this embodiment. The arc of the outer peripheral surface 13a to be measured may be any number of times as long as it is less than 180 deg. Since the arc is less than 180 deg, the shape of the outer peripheral surface 13a to be measured cannot be accurately measured in the measurement by the conventional technique using the differential transformer displacement meter, but the measurement method according to the present invention provides good accuracy. You can expect the measurement result.

Further, in the present embodiment, the shaft member has been described as the rack shaft 10, but the present embodiment is not limited to this mode. Any shaft member may be applied as long as it has a reference outer peripheral surface (first shaft portion) as a reference. For example, a shaft for a butterfly valve used for a throttle body or the like which is an engine component may be used.

Further, in the above embodiment, in the second step (steps S20-S28), the non-contact laser sensor (laser sensor 23_Ph1,24_Ph2, 25_Ph3) moves in the axial direction of the rack shaft 10 (shaft member) while moving. The positions of a plurality of target points (TP1, TP2, TP3) having different axial positions on the outer peripheral surface 13a to be measured were measured. However, the present invention is not limited to this mode, and the positions of a plurality of target points having different axial positions may be measured by using a plurality of fixed laser sensors. The same applies to the first step.

Further, in the above embodiment, a non-contact laser sensor (laser sensor 23_Ph1,24_Ph2,25_Ph3) was used to measure the outer shape of the rack shaft 10 (shaft member). However, it is not limited to this aspect. A contact type sensor may be applied instead of the non-contact type laser sensor. In this case, the applicable contact sensor has a cylindrical contact that can move in the measurement direction and is in contact with a reference point (RP1, RP2, RP3) and a target point (TP1, TP2, TP3). It suffices if the end face of is provided with a plane orthogonal to the measurement direction. Even with this, a corresponding effect can be expected.

Further, in the above embodiment, the first sensor 21 and the second sensor 22 have been described as being the same sensor. However, it is not limited to this aspect. The first sensor 21 and the second sensor 22 may be provided separately. In this case, the measurement of the reference point (first to third reference points RP1, RP2, RP3) by the first sensor 21 and the target point (first to third target points TP1, TP2, TP3) by the second sensor 22. It is efficient because the measurement can be performed at the same time.

(4. Effect of the embodiment)
According to the method for measuring the shape of the shaft member of the above embodiment, in each of the predetermined phases (first to third predetermined phases Ph1, Ph2, Ph3) in the circumferential direction on the reference outer peripheral surface 12a (first shaft portion). Multiple (two points) reference points (first to third reference points RP1, RP2, RP3) with different axial positions were actually measured, and multiple (two points) reference points (first to third reference points) were measured. The positions of the ideal target points (first to third ideal target points ITP1, ITP2, ITP3) on the outer peripheral surface 13a (second axis portion) to be measured are calculated and estimated from the points RP1, RP2, RP3). Further, the target point on the outer peripheral surface 13a to be measured is located in the same phase as the predetermined phase (first to third predetermined phases Ph1, Ph2, Ph3) of the reference points (first to third reference points RP1, RP2, RP3). The positions of (first to third target points TP1, TP2, TP3) are measured. Then, the positions of the measured target points (first to third target points TP1, TP2, TP3) and the ideal target points (third) corresponding to the measured reference points (first to third reference points RP1, RP2, RP3). By comparing the positions of the first to third ideal target points ITP1, ITP2, ITP3), the difference between the reference outer peripheral surface 12a and the measured outer peripheral surface 13a in the same phase, that is, the measured outer peripheral surface with respect to the reference outer peripheral surface 12a. The displacement amount of 13a is obtained. As a result, unlike the prior art, the displacement amount (strain amount) of the second shaft portion can be accurately measured even if the outer peripheral surface 13a to be measured of the second shaft portion does not have a large arc.

Further, according to the above embodiment, in the second step, a plurality of target points (first to third) having different axial positions on the outer peripheral surface 13a to be measured while moving in the axial direction of the rack shaft 10 (shaft member). The positions of the target points TP1, TP2, TP3) are measured, and in the third step, the displacement amount (first to third displacement amount Q1,) with respect to a plurality of target points (first to third target points TP1, TP2, TP3) is performed. Calculate Q2 and Q3). In this way, since the displacement amount of the outer peripheral surface 13a to be measured is measured while moving in the axial direction, the strain (deformation) of the rack shaft 10 (shaft member) can be measured accurately.

Further, according to the above embodiment, the first sensor (laser sensor 23_Ph1,24_Ph2, 25_Ph3) is a non-contact type sensor, and the first step is performed while moving in the axial direction of the rack shaft 10 (shaft member). , Measure the positions of a plurality of reference points (first to third reference points RP1, RP2, RP3) having different axial positions. The second sensor (laser sensor 23_Ph1,24_Ph2, 25_Ph3) is a non-contact type sensor, and in the second step, each object is moved on the outer peripheral surface 13a to be measured while moving in the axial direction of the rack shaft 10 (shaft member). The positions of the points (first to third target points TP1, TP2, TP3) are measured. In this way, the shape of the outer peripheral surface 13a to be measured is measured by the non-contact sensor while moving in the axial direction, so that distortion (deformation) occurs in a short time over the entire length of the rack shaft 10 (shaft member). It can be measured accurately.

Further, according to the above embodiment, the outer peripheral surface 13a (second shaft portion) to be measured is not provided with a non-arc outer peripheral surface formed in a non-arc shape different from the arc shape of the outer peripheral surface 13a to be measured in the circumferential direction. It is a perfect cylinder. The second shaft portion formed of such an incomplete cylinder is easily distorted, and it is difficult to measure the outer peripheral surface shape. However, in the shape measuring method according to the present invention, even an incomplete cylinder provided with a non-arc outer peripheral surface can accurately measure the outer peripheral surface shape.

Further, according to the above embodiment, the rack teeth 16 are formed on the outer peripheral surface 13a (second shaft portion) to be measured so as to face the outer peripheral surface 13a to be measured. In this way, even if the rack shaft 10 (shaft member) has the rack teeth 16, by measuring the outer peripheral surface 13a to be measured formed in the arc shape of the portion facing the rack teeth 16 with high accuracy. The shape of the outer peripheral surface can be measured.

Further, according to the above embodiment, the outer peripheral surface 13a to be measured of the second shaft portion is formed in a range of less than 180 degrees around the axis in the circumferential direction. As described above, the arc of the outer peripheral surface 13a to be measured is formed at less than 180 degrees in the circumferential direction, and even if the axis of the arc cannot be accurately detected by the differential transformer according to the prior art, the shape measuring method according to the present invention. Then, the strain of the outer peripheral surface 13a to be measured can be measured with high accuracy.

Further, according to the above embodiment, in the first step, the positions of the plurality of first reference points RP1 located at the first predetermined phase Ph1 on the reference outer peripheral surface 12a and having different axial positions, less than 90 ° from the first predetermined phase. Measure the positions of a plurality of second reference points RP2 that are located in the second predetermined phase Ph2 and have different axial positions, and are located in the third predetermined phase Ph3 that is less than 90 ° from the first predetermined phase Ph1 and have an axis. The positions of a plurality of third reference points RP3 having different directional positions are measured. In the second step, the position of the first target point TP1 located in the same phase as the first predetermined phase Ph1 and the position of the second target point TP2 located in the same phase as the second predetermined phase Ph2 are measured on the outer peripheral surface 13a to be measured. Then, the position of the third target point TP3 located in the same phase as the third predetermined phase Ph3 is measured. Further, in the third step, the first ideal target point ITP1 corresponding to the plurality of first reference points RP1 is calculated in the radial cross section including the first target point TP1. Further, the second ideal target point ITP2 corresponding to the plurality of second reference points RP2 is calculated in the radial cross section including the second target point TP2. Further, the third ideal target point ITP3 corresponding to the plurality of third reference points RP3 is calculated in the radial cross section including the third target point TP3. Then, by comparing the first ideal target point ITP1 and the first target point TP1, the displacement amount (first displacement amount Q1) of the measured outer peripheral surface 13a with respect to the reference outer peripheral surface 12a in the first predetermined phase Ph1 is calculated. .. Further, by comparing the second ideal target point ITP2 and the second target point TP2, the displacement amount (second displacement amount Q2) of the measured outer peripheral surface 13a with respect to the reference outer peripheral surface 12a in the second predetermined phase Ph2 is calculated. .. Further, by comparing the third ideal target point ITP3 and the third target point TP3, the displacement amount (second displacement amount Q3) of the measured outer peripheral surface 13a with respect to the reference outer peripheral surface 12a in the third predetermined phase Ph3 is calculated.

In this way, three phases are set in the circumferential direction on the reference outer peripheral surface 12a, and the displacement amount Q1-Q3 of the measured outer peripheral surface 13a with respect to the reference outer peripheral surface 12a is calculated for each of the three phases. Distortion (deformation) of the outer peripheral surface 13a to be measured can be detected well.

Further, according to the above embodiment, the first sensor 21 (laser sensor 23_Ph1,24_Ph2, 25_Ph3) is in a direction orthogonal to the axis of the rack shaft 10 (shaft member), and is a reference point (first to third reference points). It is a sensor that measures the position of a reference point (first to third reference points RP1, RP2, RP3) in a predetermined measurement direction DR1, DR2, DR3 that passes through the points RP1, RP2, RP3). The first sensor 21 (laser sensor 23_Ph1,24_Ph2, 25_Ph3) has a predetermined measurement range in a direction orthogonal to a predetermined measurement direction DR1, DR2, DR3. Further, the sensor reference planes E1, E2, E3 separated from the reference outer peripheral surface 12a orthogonal to the predetermined measurement directions DR1, DR2, DR3 within a predetermined measurement range are provided. The distance between the sensor reference surfaces E1, E2, E3 and the reference points (first to third reference points RP1, RP2, RP3) is other than the reference points on the sensor reference surfaces E1, E2, E3 and the reference outer peripheral surface 12a. By setting the shortest distance L1, L2, L3 with respect to the distance from the point, the positions of the reference points (first to third reference points RP1, RP2, RP3) can be measured.

The second sensor 22 (laser sensor 23_Ph1,24_Ph2, 25_Ph3) is in a direction orthogonal to the axis of the rack shaft 10 (shaft member) and passes through the target points (first to third target points TP1, TP2, TP3). It is a sensor that measures the position of a target point (first to third target points TP1, TP2, TP3) in a predetermined measurement direction DR1, DR2, DR3. The second sensor 22 has a predetermined measurement range in a direction orthogonal to the predetermined measurement directions DR1, DR2, and DR3. Further, the sensor reference planes E1, E2, and E3 separated from the outer peripheral surface 13a to be measured, which are orthogonal to the predetermined measurement directions DR1, DR2, and DR3 within a predetermined measurement range, are provided. The distance between the sensor reference surfaces E1, E2, E3 and the target points (first to third target points TP1, TP2, TP3) is other than the target points on the sensor reference surfaces E1, E2, E3 and the outer peripheral surface 13a to be measured. By setting the shortest distances L4, L5, and L6 with respect to the distance from the point, the positions of the target points (first to third target points TP1, TP2, TP3) can be measured.

With such a configuration, within a predetermined measurement range, the first and second sensors 21 and 22 have a reference point (first to third reference points RP1, RP2, RP3) and a target point (first to third objects). The positions of points TP1, TP2, TP3) can be measured accurately and reliably. That is, even if the arc of the outer peripheral surface 13a to be measured is small, the positions of the reference point and the target point can be accurately obtained, and the displacement amount of the outer peripheral surface 13a to be measured can be accurately obtained.

Further, according to the above embodiment, the first and second sensors 21 and 22 are laser sensors (laser sensor 23_Ph1,24_Ph2, 25_Ph3), and the laser sensor 23_Ph1,24_Ph2, 25_Ph3 has a predetermined spot diameter φD1, φD2, φD3. The directions of the optical axes of the laser beams LB1, LB2, and LB3 irradiated with the above coincide with the predetermined measurement directions DR1, DR2, and DR3, and the predetermined measurement range coincides with the predetermined spot diameters φD1, φD2, φD3. By increasing the spot diameters of the laser beams LB1, LB2, and LB3 in this way, a wide measurement range can be secured, and the reference point and the target point can be reliably measured, so that low cost can be supported.

Further, according to the above embodiment, the shape measuring device 20 of the rack shaft 10 (shaft member) includes a long shaft portion 12 (first shaft portion) having a reference outer peripheral surface 12a having a circular radial cross section. A rack tooth forming portion 13 (second shaft portion) having an outer peripheral surface 13a to be measured formed in an arc shape having a radial cross section having the same diameter as the reference outer peripheral surface 12a is provided. The shape measuring device 20 is located in a predetermined phase (first to third predetermined phases Ph1, Ph2, Ph3) on the reference outer peripheral surface 12a, and has a plurality of reference points (first to third reference points RP1, Ph3) having different axial positions. A non-contact type first sensor 21 (laser sensor 23_Ph1,24_Ph2, 25_Ph3) that measures the position of RP2, RP3) and a target point (first to third objects) located in the same phase as a predetermined phase on the outer peripheral surface to be measured. Corresponds to the non-contact type second sensor 22 (laser sensor 23_Ph1,24_Ph2, 25_Ph3) that measures the position of the points TP1, TP2, TP3) and a plurality of reference points having different axial positions in the radial cross section including the target point. The ideal target points (first to third ideal target points ITP1, ITP2, ITP3) to be measured are calculated, and the displacement amount of the measured outer peripheral surface 13a with respect to the reference outer peripheral surface 12a is calculated by comparing the ideal target point with the target point. The control unit 40 is provided. With this shape measuring device 20, the shape of the outer peripheral surface can be measured with high accuracy as in the case of the measurement by the above shape measuring method.

10; Shaft member (rack shaft), 12; First shaft portion (long shaft portion), 12a; Reference outer peripheral surface, 13; Second shaft portion (rack tooth forming portion), 13a; Outer peripheral surface to be measured, 20; Shape Measuring device, 21; 1st sensor, 22; 2nd sensor, 23_Ph1,24_Ph2, 25_Ph3; Laser sensor, 30; Sensor rail, 40; Control unit, 41; Storage unit, DR1, DR2, DR3; Measurement direction, E1, E2, E3; sensor reference plane, ITP1, ITP2, ITP3; ideal target point, LB1, LB2, LB3; laser beam, L1, L2, L3, L4, L5, L6; shortest distance, P1; first position, P2; Second position, Ph1, Ph2, Ph3; predetermined phase, Q1, Q2, Q3; displacement amount, RP1, RP2, RP3; reference point, TP1, TP2, TP3; target point, φD1, φD2, φD3; spot diameter.

Claims (11)

A first shaft portion having a reference outer peripheral surface having a circular radial cross section, and a second shaft portion having an arc-shaped outer peripheral surface to be measured having a radial cross section having the same diameter as the reference outer peripheral surface. A method for measuring the shape of a shaft member provided with,
A first step of measuring the positions of a plurality of reference points located in a predetermined phase and different in axial positions on the reference outer peripheral surface by a contact type or non-contact type first sensor.
A second step of measuring the position of a target point located in the same phase as the predetermined phase on the outer peripheral surface to be measured by a contact type or non-contact type second sensor.
The displacement of the outer peripheral surface to be measured with respect to the reference outer peripheral surface by calculating the ideal target point corresponding to the plurality of reference points in the radial cross section including the target point and comparing the ideal target point with the target point. The third step to calculate the quantity and
Equipped with a,
In the second step, while moving in the axial direction of the shaft member, the positions of a plurality of target points having different axial positions on the outer peripheral surface to be measured are measured.
The third step is a method for measuring the shape of a shaft member, which calculates the amount of displacement with respect to the plurality of target points. A first shaft portion having a reference outer peripheral surface having a circular radial cross section, and a second shaft portion having an arc-shaped outer peripheral surface to be measured having a radial cross section having the same diameter as the reference outer peripheral surface. A method for measuring the shape of a shaft member provided with ,
The first step of measuring the positions of a plurality of reference points located in a predetermined phase on the reference outer peripheral surface and having different axial positions by a non- contact type first sensor.
A second step of measuring the position of a target point located in the same phase as the predetermined phase on the outer peripheral surface to be measured by a non-contact type second sensor.
The displacement of the outer peripheral surface to be measured with respect to the reference outer peripheral surface by calculating the ideal target point corresponding to the plurality of reference points in the radial cross section including the target point and comparing the ideal target point with the target point. The third step to calculate the quantity and
Bei to give a,
In the first step, the positions of the plurality of reference points having different axial positions are measured while moving in the axial direction of the shaft member.
The second step is a method for measuring the shape of a shaft member, which measures the position of the target point on the outer peripheral surface to be measured. The shaft according to claim 1 or 2 , wherein the second shaft portion is an incomplete cylinder having a non-circular outer peripheral surface formed in a non-arc shape different from the arc shape of the outer peripheral surface to be measured in the circumferential direction. Method of measuring the shape of a member. The method for measuring the shape of a shaft member according to claim 3 , wherein rack teeth are formed on the non-arc outer peripheral surface of the second shaft portion so as to face the outer peripheral surface to be measured. The method for measuring the shape of a shaft member according to claim 3 or 4 , wherein the outer peripheral surface of the second shaft portion to be measured is formed in a range of less than 180 degrees around the axis in the circumferential direction. In the first step, the positions of a plurality of first reference points located in the first predetermined phase and different from each other in the axial direction on the reference outer peripheral surface, and a plurality of positions located in the second predetermined phase and different in the axial direction. Measure the position of the second reference point and
In the second step, the position of the first target point located in the same phase as the first predetermined phase and the position of the second target point located in the same phase as the second predetermined phase on the outer peripheral surface to be measured are set. Measure and
The third step is
The first ideal target point corresponding to the plurality of first reference points is calculated in the radial cross section including the first target point.
The second ideal target point corresponding to the plurality of second reference points is calculated in the radial cross section including the second target point.
By comparing the first ideal target point with the first target point, the amount of displacement of the outer peripheral surface to be measured with respect to the reference outer peripheral surface in the first predetermined phase is calculated.
Any one of claims 1-5 , which calculates the amount of displacement of the outer peripheral surface to be measured with respect to the reference outer peripheral surface in the second predetermined phase by comparing the second ideal target point with the second target point. The method for measuring the shape of a shaft member according to item 1. In the first step, the positions of a plurality of first reference points that are located in the first predetermined phase on the reference outer peripheral surface and have different axial positions, and are located in the second predetermined phase that is less than 90 ° from the first predetermined phase. The positions of a plurality of second reference points having different axial positions are measured, and a plurality of third reference points located in a third predetermined phase less than 90 ° from the first predetermined phase and having different axial positions. Measure the position of the point and
In the second step, the position of the first target point located in the same phase as the first predetermined phase and the position of the second target point located in the same phase as the second predetermined phase are measured on the outer peripheral surface to be measured. , And the position of the third target point located in the same phase as the third predetermined phase is measured.
The third step is
The first ideal target point corresponding to the plurality of first reference points is calculated in the radial cross section including the first target point.
The second ideal target point corresponding to the plurality of second reference points is calculated in the radial cross section including the second target point.
The third ideal target point corresponding to the plurality of third reference points is calculated in the radial cross section including the third target point.
By comparing the first ideal target point with the first target point, the amount of displacement of the outer peripheral surface to be measured with respect to the reference outer peripheral surface in the first predetermined phase is calculated.
By comparing the second ideal target point with the second target point, the amount of displacement of the outer peripheral surface to be measured with respect to the reference outer peripheral surface in the second predetermined phase is calculated.
Any one of claims 1-5 , which calculates the amount of displacement of the outer peripheral surface to be measured with respect to the reference outer peripheral surface in the third predetermined phase by comparing the third ideal target point with the third target point. The method for measuring the shape of a shaft member according to item 1. The first sensor is
A sensor that measures the position of the reference point in a predetermined measurement direction that is orthogonal to the axis of the shaft member and passes through the reference point.
A predetermined measurement range is provided in a direction orthogonal to the predetermined measurement direction.
A sensor reference plane away from the reference outer peripheral surface that is orthogonal to the predetermined measurement direction within the predetermined measurement range is provided.
The position of the reference point can be measured by making the distance between the sensor reference surface and the reference point the shortest distance with respect to the distance between the sensor reference surface and the point other than the reference point on the reference outer peripheral surface. Next,
The second sensor is
A sensor that measures the position of the target point in a predetermined measurement direction that is orthogonal to the axis of the shaft member and passes through the target point.
A predetermined measurement range is provided in a direction orthogonal to the predetermined measurement direction.
A sensor reference plane away from the outer peripheral surface to be measured, which is orthogonal to the predetermined measurement direction within the predetermined measurement range, is provided.
The position of the target point is measured by making the distance between the sensor reference surface and the target point the shortest distance with respect to the distance between the sensor reference surface and the outer peripheral surface to be measured other than the target point. The method for measuring the shape of a shaft member according to any one of claims 1 to 7, which is possible. The first and second sensors are laser sensors.
The direction of the optical axis of the laser beam emitted by the laser sensor with a predetermined spot diameter coincides with the predetermined measurement direction.
The method for measuring the shape of a shaft member according to claim 8 , wherein the predetermined measurement range coincides with the predetermined spot diameter. A first shaft portion having a reference outer peripheral surface having a circular radial cross section, and a second shaft portion having an arc-shaped outer peripheral surface to be measured having a radial cross section having the same diameter as the reference outer peripheral surface. A shaft member shape measuring device provided with,
A contact-type or non-contact-type first sensor that measures the positions of a plurality of reference points that are located in a predetermined phase on the reference outer peripheral surface and have different axial positions.
A contact-type or non-contact-type second that measures the positions of a plurality of target points in the same phase as the predetermined phase and different in the axial direction while moving in the axial direction of the shaft member on the outer peripheral surface to be measured. With the sensor
It calculates the ideal target point corresponding to the plurality of reference points in radial cross-section that includes the target point, the said measured outer peripheral surface with respect to the reference outer peripheral surface by comparing the target point and the ideal target point A control unit that calculates the amount of displacement for a plurality of the target points,
A shaft member shape measuring device comprising. A first shaft portion having a reference outer peripheral surface having a circular radial cross section, and a second shaft portion having an arc-shaped outer peripheral surface to be measured having a radial cross section having the same diameter as the reference outer peripheral surface. A shaft member shape measuring device provided with,
A non-contact type first sensor that measures the positions of a plurality of reference points that are located in a predetermined phase and have different axial positions while moving in the axial direction of the shaft member on the reference outer peripheral surface.
A non-contact type second sensor that measures the position of a target point located in the same phase as the predetermined phase on the outer peripheral surface to be measured.
By calculating the ideal target points corresponding to the plurality of reference points in the radial cross section including the target points and comparing the ideal target points with the target points, the said outer peripheral surface to be measured with respect to the reference outer peripheral surface. A control unit that calculates the amount of displacement related to the target point,
A shaft member shape measuring device comprising.

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