JP7801952B2 - Contact probe stylus - Google Patents

Description

This disclosure relates to a stylus for a contact probe.

Patent Document 1 discloses a probing device for measuring the shape and dimensions of a workpiece machined by a machine tool. The device includes a stylus configured to contact the surface of the workpiece to measure the workpiece, and a feeder configured to hold and move the stylus. A roughly spherical contactor (tip) is provided at the tip of the stylus. The feeder moves the stylus closer to the workpiece, and the position of the contactor when it comes into contact with the workpiece is obtained, thereby measuring the shape and dimensions of the workpiece.

Japanese Patent Application Laid-Open No. 2021-181132

This disclosure describes a contact probe stylus that is highly durable and capable of measuring processed products with complex shapes.

An example of a contact probe stylus has a base end portion having a columnar shape extending along a predetermined first direction, and a tip end portion connected to the base end. The tip end portion has a generally triangular prism shape that tapers from the base end toward the tip end of the tip end portion, and includes a first main surface extending along the first direction, a second main surface located opposite the first main surface in a second direction perpendicular to the first direction and extending at an angle relative to the first direction, and a contactor located at the tip. The inclination angle formed by the first main surface and the second main surface is acute. The surface of the contactor has a generally arc shape when viewed from a third direction perpendicular to both the first and second directions. The portion of the contactor on the first main surface side protrudes beyond the first main surface in a direction from the second main surface toward the first main surface.

The contact probe stylus disclosed herein makes it possible to measure highly durable processed products with complex shapes.

FIG. 1 is a perspective view showing an example of a processing apparatus. FIG. 2 is a perspective view of an example of a stylus of a contact probe, as viewed from the rear side. FIG. 3 is a perspective view of the stylus of FIG. 2 as seen from the front side. FIG. 4 is a partial cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a diagram showing an example of the movement locus of the tip of the stylus of the contact probe when the stylus measures the processed product.

In the following description, the same elements or elements with the same functions will be designated by the same reference numerals, and redundant explanations will be omitted. In this specification, when referring to the top, bottom, right, and left of a figure, reference will be made to the orientation of the reference numerals in the figure. Figure 1 illustrates an example of a Cartesian coordinate system defined by the X, Y, and Z axes. In this Cartesian coordinate system, the Y axis extends vertically upward (first direction), the X axis extends horizontally (third direction) so as to be perpendicular to the Y axis, and the Z axis extends horizontally (second direction) so as to be perpendicular to both the X and Y axes.

[Configuration of processing device]
First, referring to FIG. 1 , a processing device 1 equipped with a contact probe 10 will be described. The processing device 1 has a function of processing a workpiece W (e.g., a metal block) and a function of measuring the shape and dimensions of a processed product P obtained by processing the workpiece W. The processed product P may be, for example, a mold part. The mold part may be, for example, a component constituting a punching device that punches out a sheet-like base material (e.g., a metal plate). The shape of the processed product P may be, for example, a rectangular parallelepiped, a cylindrical shape, a polygonal prism, or any other irregular shape.

As shown in FIG. 1, the processing device 1 includes a base unit 2, a processing unit 3, a measurement unit 4, a display 5, and a controller Ctr (control unit). The processing device 1 may further include a housing (not shown) configured to accommodate some or all of these components.

The base unit 2 includes a base 2a, a guide mechanism 2b, and a stage 2c. The base 2a is configured to support the guide mechanism 2b and the stage 2c from below. The guide mechanism 2b is attached to the base 2a. The guide mechanism 2b may be, for example, a linear actuator. The guide mechanism 2b may include, for example, a rail 2d and a block (not shown). The block may be configured to be able to move back and forth along the rail 2d (Z-axis) based on instructions from the controller Ctr.

Stage 2c is configured to suction-hold a workpiece W or a processed product P placed on its upper surface (mounting surface). Stage 2c may be, for example, a magnetic chuck or a vacuum chuck. Stage 2c may hold at least one workpiece W or processed product P, or may hold multiple workpieces W or processed products P. Stage 2c may be connected to a block of guide mechanism 2b. Therefore, when the block moves back and forth along rail 2d, the workpiece W or processed product P held on stage 2c also moves back and forth along rail 2d (Z-axis).

The processing unit 3 has the function of processing the workpiece W so that it becomes a processed product P of a predetermined shape. The processing unit 3 may be disposed above the base unit 2. The processing unit 3 includes a tool 3a, a shaft 3b, a cover member 3c, and a drive mechanism 3d.

The tool 3a is configured to process the workpiece W while in contact with the workpiece W. For example, if the processing device 1 is a grinding device, the tool 3a may be a grinding stone that grinds the workpiece W. The grinding stone may be, for example, a grinding wheel with an abrasive layer provided on a rotating wheel. The shape of the grinding wheel may be, for example, shape symbol "4B2" (so-called single V-face) defined in JIS B 4141:1998 (see Figure 1) or "1EE1" (so-called V-face). The tip diameter of the grinding wheel may be, for example, approximately 30 μm to 60 μm for finish processing and approximately 50 μm to 200 μm for rough processing. The tip angle of the grinding wheel may be, for example, approximately 10° to 40°.

The shaft 3b extends along the X-axis. The tool 3a is attached to one end of the shaft 3b. The central axis of the shaft 3b and the central axis of the tool 3a may be approximately aligned. The drive mechanism 3d is attached to the other end of the shaft 3b.

The cover member 3c is configured to prevent chips and dust generated when the workpiece W is machined by the tool 3a from scattering around. The cover member 3c is attached to the drive mechanism 3d via the plate 3e so as to cover the periphery of the tool 3a. As illustrated in FIG. 1, the cover member 3c includes a back plate that covers the back surface of the tool 3a and a pair of side plates that cover each side surface of the tool 3a, and may have a roughly C-shape when viewed from the Y-axis direction. The cover member 3c and the plate 3e may be provided with a through-hole or cutout through which the shaft 3b can be inserted.

The drive mechanism 3d is configured to support and rotate the shaft 3b based on instructions from the controller Ctr. As the shaft 3b rotates, the tool 3a also rotates, with the central axis of the shaft 3b as the axis of rotation. The drive mechanism 3d is configured to move the shaft 3b and the cover member 3c up and down along the Y axis based on instructions from the controller Ctr. At this time, the tool 3a attached to the shaft 3b also moves back and forth in the vertical direction. The drive mechanism 3d is configured to move the shaft 3b and the cover member 3c back and forth along the X axis based on instructions from the controller Ctr. At this time, the tool 3a attached to the shaft 3b also moves back and forth in the horizontal direction. The operation timing and operation speed of the shaft 3b and the cover member 3c by the drive mechanism 3d, the number of rotations of the shaft 3b, etc. may be set, for example, based on design data (e.g., CAD data) of the processed product P stored in the controller Ctr.

The measurement unit 4 is configured to measure the shape and dimensions of the workpiece W processed by the processing unit 3, i.e., the processed product P. The measurement unit 4 includes a support member 4a and a contact probe 10.

The support member 4a is attached to the plate 3e. By providing the support member 4a on the relatively rigid plate 3e in this way, vibrations are less likely to be transmitted to the support member 4a, improving the measurement accuracy of the measurement unit 4. The support member 4a may be located adjacent to the side of the cover member 3c, as shown in FIG. 1. The support member 4a supports the contact probe 10 in a suspended state. Therefore, the contact probe 10 is located above the stage 2c.

The support member 4a may include a drive mechanism (not shown) and may be configured to move the contact probe 10 up and down based on instructions from the controller Ctr. For example, the support member 4a may raise the contact probe 10 when the workpiece W is being processed by the processing unit 3, and may lower the contact probe 10 when the workpiece W is not being processed by the processing unit 3 and the processed product P is being measured.

The contact probe 10 includes a housing 11 and a stylus 20. The housing 11 is supported by a support member 4a. The housing 11 elastically holds the stylus 20 via an elastic member (e.g., a coil spring) not shown. Therefore, when the stylus 20 comes into contact with the processed product P, the stylus 20 is pushed into the housing 11. A sensor (not shown) is provided within the housing 11, and when the sensor detects a change in the position of the stylus 20, it is determined that the stylus 20 has come into contact with the processed product P.

The stylus 20 may be made of a cemented carbide (e.g., tungsten carbide). As illustrated in Figures 2 to 4, the stylus 20 includes a base end 21, a tip end 22, and a contact 23.

When attached to the housing 11, the base end 21 extends in the vertical direction (Y-axis). The base end 21 may have a rectangular prism shape (see Figures 2 and 3) or another shape (e.g., another rectangular prism shape, a cylindrical shape, etc.). The base end 21 includes a pair of principal surfaces S1, S2 that face each other in the horizontal direction (X-axis). The principal surfaces S1, S2 extend in the vertical direction (Y-axis). The principal surface S1 may be recessed toward the principal surface S2 at the lower part of the base end 21 (see Figures 2 and 4). In other words, the principal surface S1 may have a stepped shape. In this case, the portion 21a (first portion) of the upper part of the base end 21 on the principal surface S1 side protrudes outward more than the portion 21b of the lower part of the base end 21 on the principal surface S1 side.

The tip portion 22 is integrally connected to the tip (lower end) of the base portion 21. The tip portion 22 has a triangular prism shape that tapers from the base portion 21 toward the tip of the tip portion 22. Therefore, the tip portion 22 has a triangular shape when viewed from the side (Z axis).

The tip portion 22 includes a pair of principal surfaces S3, S4 that face each other in the horizontal direction (X-axis). The principal surface S3 (first principal surface) extends along the vertical direction (Y-axis). That is, the principal surface S3 extends integrally and continuously with the principal surface S1. The principal surface S4 is located on the opposite side of the principal surface S3 in the horizontal direction (X-axis). The principal surface S4 extends at an angle relative to the vertical direction (Y-axis). Therefore, the principal surface S4 extends at a bent angle from the lower end of the principal surface S2.

The inclination angle θ (see Figure 4) formed by the main surfaces S3 and S4 is an acute angle. The inclination angle θ may be set smaller than the tip angle of the grinding wheel used to machine the workpiece W. The inclination angle θ may be, for example, approximately 5° to 35°, or approximately 8° to 28°.

The contactor 23 is provided at the tip (lower end) of the tip portion 22. When viewed from the side (Z axis), the contactor 23 has a fan shape. That is, when viewed from the side (Z axis), the surface of the contactor 23 has a generally arc-like shape. In other words, the contactor 23 has a shape similar to a cylinder partially cut away along its central axis (a generally semi-cylindrical shape). The radius r of the contactor 23 may be, for example, approximately 15 μm to 200 μm, or approximately 25 μm to 150 μm. The radius r of the contactor 23 may be set smaller than the tip diameter of the grinding wheel used to machine the workpiece W, or may be set smaller than the smallest radius of curvature of the surface shape of the processed product P. The central angle φ of the contactor 23 may be, for example, approximately 150° to 200°. In this case, it is possible to increase the rigidity of the stylus 20 while making it more compact.

As illustrated in Figures 2 and 4, the portion 23a (second portion) of the contactor 23 on the main surface S3 side protrudes outward beyond the main surface S3. That is, the portion 23a of the contactor 23 on the main surface S3 side protrudes beyond the main surface S3 in the direction from the main surface S4 toward the main surface S3 (the negative side of the X-axis). In other words, the main surface S3 is recessed relative to the portion 21a of the upper part of the base end 21 on the main surface S1 side and the portion 23a of the contactor 23 on the main surface S3 side. Therefore, the main surface S3 and the portions 21a and 23a form a recess C.

When viewed from the top-bottom direction (Y-axis), portion 23a overlaps portion 21a. In this case, processing the flat plate to create the stylus 20 is easier.

As illustrated in Figure 4, when viewed from the side (Z axis), the contactor 23 and the main surface S4 are connected at the intersection Q. When viewed from the side (Z axis), the tangent to the contactor 23 at the intersection Q may be approximately coincident with the main surface S4. In this case, the contactor 23 extends continuously from the main surface S4, making it easier to ensure the rigidity of the stylus 20. In addition, this makes it easier to process the stylus 20 by machining a flat plate.

The display 5 has the function of displaying various information on the screen based on instructions from the controller Ctr. The information displayed on the display 5 may include, for example, the size of the workpiece W or the processed product P, the position of the workpiece W or the processed product P, the processing conditions, the measurement conditions, and the movement path T (see FIG. 5) described below.

The controller Ctr is configured to generate instruction signals for operating each part of the processing device 1 (guide mechanism 2b, drive mechanism 3d, measurement unit 4) based on, for example, a program recorded on a recording medium (not shown) or operation input from an operator, and to transmit these instruction signals to each of these parts. The controller Ctr is configured to receive measurement data of the processed product P measured by the measurement unit 4 from the measurement unit 4.

[Method for measuring processed products using a contact probe]
Next, a method for measuring the processed product P using the contact probe 10 will be described with reference to Fig. 5. First, the controller Ctr reads design data for the processed product P and calculates a movement path T of the stylus 20 based on the shape of the processed product P.

As illustrated in FIG. 5, the movement path T may include measurement points M for measuring the linear portions of the processed product P and measurement points N for measuring the curved portions of the processed product P. The ratio of the number of measurement points N to the length of the curved portions of the processed product P may be set to be greater than the ratio of the number of measurement points M to the length of the linear portions of the processed product P. Alternatively, the number of measurement points M may be approximately one to three per linear portion, and the number of measurement points N may be the number obtained by dividing the angle of the curved portion by a reference angle (e.g., 5° to 20°).

Next, the controller Ctr instructs each part of the processing device 1 (guide mechanism 2b, drive mechanism 3d, measurement unit 4) to move the stylus 20 along the movement path T. When the stylus 20 reaches the starting point of measurement points M and N, the controller Ctr instructs the drive mechanism 3d to lower the contact probe 10, together with the cover member 3c, toward the processed product P, bringing it into contact with the measurement point from a vertical direction.

When the stylus 20 comes into contact with the processed product P, the contact probe 10 transmits position information at that time to the controller Ctr, and the controller Ctr instructs the drive mechanism 3d to raise the contact probe 10 together with the cover member 3c. The stylus 20 is then moved along the movement path T in the same manner, and when the stylus 20 reaches the measurement points M and N, the contact probe 10 is moved up and down or horizontally to measure the shape and dimensions of the processed product P.

[Effect]
According to the above example, the tip 22 has a triangular prism shape, and the portion 23a of the contactor 23, extending from the main surface S3 to the apex, primarily contacts the workpiece P, thereby dispersing the load (reaction force) during contact. This results in a stylus 20 with superior strength compared to conventional styluses with spherical contactors attached to the tip of a stylus shaft. Furthermore, the surface of the contactor 23 has a generally arc-shaped shape with a radius of 15 μm to 200 μm. Therefore, the tip diameter of the contactor 23 is smaller than the tip diameter of commonly used machining tools. This enables measurement of extremely small machining areas. Furthermore, the portion 23a of the contactor 23 on the main surface S3 side protrudes beyond the main surface S3 in the direction from the main surface S4 toward the main surface S3. Therefore, when the portion 23a of the contactor 23 contacts the workpiece P, the main surface S3 is less likely to come into contact with the workpiece P. This increases the surface area of the contactor 23, enabling measurement of workpieces P with complex shapes.

In the above example, the tilt angle θ may be, for example, approximately 5° to 35°. When the tilt angle θ is 5° or more, the strength of the stylus 20 increases, which tends to extend the life of the stylus 20. When the tilt angle θ is 35° or less, the surface area of the contact 23 increases, which tends to enable measurement of processed products P with more complex shapes.

In the above example, the main surface S3 may be recessed relative to the portion 21a of the base end 21 on the main surface S3 side and the portion 23a of the contact 23 on the main surface S3 side. In this case, the recess (recess C) can easily create a state in which the portion 23a of the contact 23 on the main surface S3 side protrudes further than the main surface S3 in the direction from the main surface S4 toward the main surface S3.

[Modification]
The disclosure in this specification should be considered to be illustrative in all respects and not restrictive. Various omissions, substitutions, modifications, etc. may be made to the above examples without departing from the scope and spirit of the claims.

(1) The main surface S1 does not have to be stepped. That is, the upper portion 21a of the base end 21 facing the main surface S1 and the lower portion 21b of the base end 21 facing the main surface S1 may be flat. In this case, the recess C does not have to be present in the stylus 20.

[Other examples]
Example 1. An example of a stylus for a contact probe includes a base end having a columnar shape extending along a predetermined first direction and a tip end connected to the base end. The tip end has a generally triangular prism shape tapering from the base end toward the tip end of the tip end, and includes a first main surface extending along the first direction, a second main surface located opposite the first main surface in a second direction perpendicular to the first direction and extending at an angle relative to the first direction, and a contactor located at the tip. The inclination angle formed between the first main surface and the second main surface is acute. The surface of the contactor has a generally arc-shaped shape when viewed from a third direction perpendicular to both the first and second directions. A portion of the contactor on the first main surface side protrudes beyond the first main surface in a direction from the second main surface toward the first main surface. In this case, because the tip has a triangular prism shape, the contactor contacts the workpiece mainly from the first main surface side to the apex, making it easier to distribute the load (reaction force) during contact. This results in a stylus with superior strength compared to conventional styluses with spherical contactors attached to the tip of a stylus shaft. Furthermore, the portion of the contactor on the first main surface side protrudes beyond the first main surface in the direction from the second main surface toward the first main surface. Therefore, when this portion of the contactor contacts the workpiece, the first main surface is less likely to come into contact with the workpiece. This increases the surface area of the contactor, making it possible to measure workpieces with complex shapes.

Example 2. In the stylus of Example 1, the surface of the contactor may have a generally arcuate shape with a radius of 15 μm to 200 μm when viewed from the third direction. In this case, the tip diameter of the contactor is smaller than the tip diameter of a commonly used machining tool. This makes it possible to measure extremely small machining areas.

Example 3. In the stylus of Example 1 or Example 2, the tilt angle may be 5° to 35°. When the tilt angle is 5° or more, the strength of the stylus increases, which tends to extend the life of the stylus. When the tilt angle is 35° or less, the surface area of the contactor increases, which tends to enable measurement of processed products with more complex shapes.

Example 4. In any of the styluses of Examples 1 to 3, the first principal surface may be recessed relative to the portion of the base end facing the first principal surface and the portion of the contact facing the first principal surface. In this case, the recess can easily create a state in which the portion of the contact facing the first principal surface protrudes beyond the first principal surface in a direction from the second principal surface toward the first principal surface.

Example 5. In the stylus of Example 4, the first portion may overlap the second portion when viewed from the first direction. In this case, processing becomes easier when processing the flat plate to create the stylus.

Example 6. In the stylus of Example 4 or Example 5, when viewed from a third direction, the tangent to the contactor and the second main surface may coincide at the intersection of the contactor and the second main surface. In this case, the contactor extends continuously from the second main surface, making it easier to ensure the rigidity of the stylus. In addition, this makes it easier to process the stylus by machining a flat plate.

1...machining device, 10...contact probe, 20...stylus, 21...base end, 21a...portion (first portion), 22...tip end, 23...contactor, 23a...portion (second portion), C...recess, r...radius, S3...main surface (first main surface), S4...main surface (second main surface), θ...tilt angle.

Claims (6)

a base end portion having a columnar shape extending along a predetermined first direction;
a distal end connected to the proximal end,
The tip portion is
The tip portion has a generally triangular prism shape that tapers from the base end toward the tip end,
a first main surface extending along the first direction;
a second main surface located on the opposite side to the first main surface in a second direction perpendicular to the first direction and extending at an angle with respect to the first direction;
and a contact located at the tip thereof,
an inclination angle formed between the first main surface and the second main surface is an acute angle;
a surface of the contactor having a substantially arcuate shape when viewed from a third direction perpendicular to both the first direction and the second direction;
A stylus of a contact probe, wherein a portion of the contactor on the first main surface side protrudes beyond the first main surface in a direction from the second main surface toward the first main surface. The stylus of claim 1, wherein the surface of the contactor has a generally arcuate shape with a radius of 15 μm to 200 μm when viewed from the third direction. The stylus of claim 2, wherein the tilt angle is between 5° and 35°. A stylus according to any one of claims 1 to 3, wherein the first main surface is recessed relative to a first portion of the base end on the first main surface side and a second portion of the contact on the first main surface side. The stylus of claim 4, wherein the first portion overlaps the second portion when viewed from the first direction. The stylus of claim 5, wherein, when viewed from the third direction, a tangent to the contact and the second main surface coincide at the intersection of the contact and the second main surface.