JP6063233B2 - Probe support mechanism and probe - Google Patents

Description

  The present invention relates to a probe support mechanism and a probe, for example, a probe support mechanism and a probe used for shape measurement.

  Today, in order to inspect the processing accuracy of a product having a three-dimensional shape, a shape measuring means such as a three-dimensional measuring machine is used. Such a three-dimensional measuring machine performs shape measurement, for example, by moving the scanning probe along a three-dimensional shape.

  The probe is provided with a contact that contacts the measurement object at the tip of the stylus. The contact has, for example, a spherical shape. In this case, the contact is referred to as a tip sphere. When the tip sphere comes into contact with the object to be measured, the tip sphere is displaced under the force of the contact. The three-dimensional measuring machine scans the surface of the measurement object so that the displacement of the tip sphere is constant, and outputs a measurement result by calculating the acquired coordinate value.

  The following functions are required for the probe of the CMM. The first is a sensing function that detects minute displacements ΔX, ΔY, ΔZ in the X, Y, and Z axis directions of the measuring element. As a result, it is possible to perform shape measurement that accurately captures changes in the probe. Second, there is no anisotropy in detecting displacement of the probe in the X, Y, and Z axis directions. Thereby, errors and distortions of the measured shape can be prevented. Thirdly, disturbances such as probe speed fluctuations and drive vibrations occur during probe scanning by the coordinate measuring machine (approach to the measurement object and movement such as scanning measurement of the surface to be measured). In order to prevent the measurement accuracy from being deteriorated due to such disturbance, it is required to have robustness against displacement due to the inertial load of the probe movable part.

  Regarding the above-described sensing function and removal of anisotropy, various measures are possible as the function of the probe alone. Regarding the robustness against the occurrence of displacement, a measurement system that provides robustness by control or correction algorithm is known (Patent Document 1). For example, when scanning measurement is performed along an arc surface of a measurement object, the movable part including the probe probe and the driving mechanism of each axis of the coordinate measuring machine receive acceleration toward the arc center. Therefore, due to the centrifugal force corresponding to the acceleration, each part is deformed and a measurement error occurs. Therefore, a sphere having a known radius of curvature or an arc of a cylinder is measured in advance by changing measurement conditions such as measurement speed, measurement direction, and measurement location, and a reference value is acquired. Then, the difference between the shape of the measurement object and the reference value and the measurement conditions are stored in the data processing apparatus as correction parameters. When actually performing the copying measurement, the correction parameter corresponding to the measurement condition is read, and the result of correcting the measurement data is output as the measurement result.

JP 2008-89578 A

  However, the inventor has found that the above-described method has the following problems. CMMs differ in basic structure, size of measurement range, drive guide mechanism, control method, etc., due to differences in measurement accuracy grades. Therefore, the disturbance applied to the probe has a different aspect.

  Also, the probe is caused by disturbances caused by measurement operations such as acceleration when approaching the measurement object, vibration due to driving until reaching the measurement object contact, and friction at the time of contact with the measurement object Subject to nonlinear mechanical disturbances such as stick-slip.

  It is difficult to obtain reference values in advance for random errors such as disturbances due to measurement environments, disturbances caused by measurement operations, and nonlinear mechanical disturbances. Therefore, the above-described correction algorithm cannot cope with such disturbance.

  The measuring element support mechanism according to the first aspect of the present invention includes a shaft member having a first direction as an axis in a state where a measuring element can be attached to a tip and no load is applied to the measuring element, A shaft member is inserted, and has elasticity that allows displacement of the shaft member in the first direction and prevents displacement of the shaft member in a plane perpendicular to the first direction. A first elastic member; a second elastic member through which the shaft member is inserted and allowing displacement of the shaft member in the axial direction of the shaft member; the first elastic member and the second elastic member; And a third elastic member that can be expanded and contracted and has flexibility.

  A probe support mechanism according to a second aspect of the present invention is the probe support mechanism described above, wherein the third elastic member is between the first elastic member and the second elastic member. The shaft member is disposed so as to surround the shaft member.

  The probe support mechanism according to the third aspect of the present invention is the probe support mechanism described above, wherein the third elastic member has one end joined to the first elastic member and the other end connected to the first elastic member. This is a bellows joined to the elastic member 2.

  A probe support mechanism according to a fourth aspect of the present invention is the probe support mechanism described above, wherein the third elastic member is between the first elastic member and the second elastic member. The space between the shaft member and the third elastic member is sealed.

  A measuring element support mechanism according to a fifth aspect of the present invention is the above-described measuring element support mechanism, which is extendable and flexible and connects the first elastic member and the second elastic member. And a fourth elastic member between the first elastic member and the second elastic member and between the third elastic member and the shaft member. It arrange | positions so that the said shaft member may be surrounded, and seals the space between a said 3rd elastic member and a said 4th elastic member.

  A probe support mechanism according to a sixth aspect of the present invention is the probe support mechanism described above, wherein the fourth elastic member has one end joined to the first elastic member and the other end connected to the first elastic member. This is a bellows joined to the elastic member 2.

  A measuring element support mechanism according to a seventh aspect of the present invention is the above-described measuring element support mechanism, wherein the space between the third elastic member and the fourth elastic member is partially filled. An incompressible viscous fluid, and a gas that fills a portion of the space between the third elastic member and the fourth elastic member that is not filled with the incompressible viscous fluid. Is.

  A probe support mechanism according to an eighth aspect of the present invention is the probe support mechanism described above, wherein the pressure of the gas is adjustable.

  A probe support mechanism according to a ninth aspect of the present invention is the probe support mechanism described above, further including a support member fixed to an external member, wherein the first elastic member is attached to the support member. The support member includes a tube portion that connects the space between the third elastic member and the fourth elastic member and the outside of the probe support mechanism, and the gas includes the tube The pressure is adjusted by a pressure adjusting device outside the probe support mechanism via the unit.

  A probe support mechanism according to a tenth aspect of the present invention is the probe support mechanism described above, wherein the third elastic member has one end joined to the first elastic member and the other end connected to the first elastic member. This is a coil spring joined to the elastic member 2.

  A probe support mechanism according to an eleventh aspect of the present invention is the probe support mechanism described above, wherein the third elastic member has one end joined to the first elastic member and the other end connected to the first elastic member. It is a three-way spring joined to the elastic member.

  A probe support mechanism according to a twelfth aspect of the present invention is the probe support mechanism described above, wherein the first elastic member and the second elastic member are arranged in the center at an opening provided in the center. This is a diaphragm composed of a disk-shaped elastic member through which the member is inserted.

  A probe support mechanism according to a thirteenth aspect of the present invention is the probe support mechanism described above, wherein the second elastic member allows displacement of the shaft member in the axial direction of the shaft member, And it has the elasticity which prevents the displacement of the said shaft member in the surface perpendicular | vertical to the axial direction of the said shaft member.

  A probe support mechanism according to a fourteenth aspect of the present invention is the probe support mechanism described above, wherein the second elastic member allows displacement of the shaft member in the axial direction of the shaft member, And it has the elasticity which accept | permits the displacement of the said shaft member in the surface perpendicular | vertical to the axial direction of the said shaft member.

  The probe according to the fifteenth aspect of the present invention has a measuring element in contact with a measuring object, and the measuring element can be attached to the tip, and the first direction is set in a state where no load acts on the measuring element. A shaft member serving as a shaft; and the shaft member is inserted, allows displacement of the shaft member in the first direction, and is perpendicular to the first direction. A first elastic member having elasticity for preventing displacement; a second elastic member through which the shaft member is inserted and allowing displacement of the shaft member in an axial direction of the shaft member; and the first elastic member. And a third elastic member that is extendable and flexible and connects the second elastic member.

  ADVANTAGE OF THE INVENTION According to this invention, the measuring element support mechanism and probe which can suppress the influence of a disturbance are realizable.

  The above and other objects, features and advantages of the present invention will be more fully understood from the following detailed description and the accompanying drawings. The accompanying drawings are presented for purposes of illustration only and are not intended to limit the present invention.

It is a perspective view which shows typically the structure of the shape measuring apparatus 100 concerning Embodiment 1. FIG. 1 is a functional block diagram of a shape measuring apparatus 100 according to a first embodiment. 3 is a cross-sectional view of the scanning probe 101 in the XZ plane. FIG. It is principal part sectional drawing of the joint parts 150 and 170 in the IV-IV line shown in FIG. It is a top view of the joint part 150 at the time of seeing from the A direction shown in FIG. It is a top view of the joint part 170 at the time of seeing from the A direction shown in FIG. FIG. 5 is an overhead view when a diaphragm 142 is viewed from the Z-axis direction. It is an overhead view at the time of looking down on the diaphragm 145 from the Z-axis direction. It is a figure which shows typically the motion of the scanning probe 101 when the contactor 182 is pushed in the Z-axis plus direction. It is a figure which shows typically the motion of the scanning probe 101 when the contactor 182 is pushed in the direction (X direction, Y direction) perpendicular | vertical to a Z-axis direction. 3 is a cross-sectional view of the scanning probe 201 in the XZ plane. FIG. 3 is a cross-sectional view of the scanning probe 301 in the XZ plane. FIG. The graph which shows the relative displacement magnification regarding the vibration amplitude between the slider 16 and the movable part of the scanning probe 301 when the probe which has arbitrary natural frequencies is mounted | worn with the three-dimensional measuring machine whose natural frequency of the slider 16 is 60 Hz. It is.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary.

Embodiment 1
First, the shape measuring apparatus 100 according to the first embodiment will be described. FIG. 1 is a perspective view schematically showing the configuration of the shape measuring apparatus 100 according to the first embodiment. The shape measuring apparatus 100 includes a coordinate measuring machine 1 and a computer 2. The coordinate measuring machine 1 and the computer 2 are connected via a cable 3.

  The coordinate measuring machine 1 is configured, for example, as shown in FIG. 1. A surface plate 11 is placed on a vibration isolation table 10, and its upper surface (base surface) coincides with a horizontal plane (XY plane in FIG. 1). To be installed. A Y-axis drive mechanism 14 extending in the Y direction is installed on one end of the surface plate 11 in the X direction. On the Y-axis drive mechanism 14, a beam support 12a is erected. Thereby, the Y-axis drive mechanism 14 drives the beam support 12a in the Y direction. On the other end of the surface plate 11 in the X direction, a beam support 12b is erected. The lower end of the beam support 12b is supported by an air bearing so as to be movable in the Y-axis direction. The beam 13 extending in the X-axis direction is supported at both ends by beam supports 12a and 12b, and supports a column 15 extending in the vertical direction (Z-axis direction). The column 15 is driven along the beam 13 in the X-axis direction. The column 15 is provided with a slider 16 so as to be driven in the Z-axis direction along the column 15. A scanning probe 17 is attached to the lower end of the slider 16. The stylus 17b is detachably attached to the attachment portion of the stylus 17b of the scanning probe 17. For example, a spherical tip sphere 17a is provided at the tip of the stylus 17b.

  The tip sphere 17a contacts the object to be measured 31 placed on the surface plate 11, and is pushed in from the reference position (neutral position) by a predetermined pushing amount. The tip sphere displacement detector 19a built in the scanning probe 17 outputs the push-in amount (in the X, Y, and Z axis directions), and the XYZ coordinate value (shift amount from the reference position) of the tip sphere 17a at that time. Is captured by the computer 2.

  The computer 2 drives and controls the coordinate measuring machine 1 to take in necessary measurement values, and executes arithmetic processing necessary for calculating the surface property of the object to be measured. The computer 2 includes a computer main body 21, a keyboard 22, a mouse 23, a monitor 24, and a printer 25. Since the keyboard 22, mouse 23, monitor 24, and printer 25 can be general ones, detailed description thereof will be omitted. Details of the computer main body 21 will be described later.

 Next, the functional configuration of the shape measuring apparatus 100 will be described with reference to FIG. FIG. 2 is a functional block diagram of the shape measuring apparatus 100 according to the first embodiment. The coordinate measuring machine 1 includes an XYZ axis driving unit 18 and a scale unit 19b. The XYZ axis drive unit 18 drives the scanning probe 17 in the XYZ axis direction. The scale unit 19b outputs a movement pulse in each axial direction of the slider 16 with the movement in the XYZ axial directions.

  The scale unit 19b includes an X-axis scale unit 19bx, a Y-axis scale unit 19by, and a Z-axis scale unit 19bz. The X-axis scale unit 19bx is disposed on the beam 13 and detects the displacement of the column 15 in the X-axis direction. The Y-axis scale unit 19by is disposed in the vicinity of the Y-axis drive mechanism 14, and detects the displacement in the Y-axis direction of the beam support 12a. The Z-axis scale portion 19bz is disposed in the column 15 and detects the displacement of the slider 16 in the Z-axis direction. The detected displacement information of the tip sphere 17a (the respective shift amounts of the XYZ axes output from the tip sphere displacement detection unit 19a) and the displacement information of the slider 16 (the respective displacements of the XYZ axes output from the scale unit 19b) are: The data is output to the calculation unit 212 described later. The scale portion 19b is adjusted to output the reference position of the tip sphere 17a when no relative displacement has occurred between the scale portion 19b and the reference position of the tip sphere 17a.

  The computer main body 21 of the computer 2 includes a storage unit 211, a calculation unit 212, a display control unit 213, and I / Fs (interfaces) 214 to 216. The storage unit 211 stores input information. The calculation unit 212 includes a CPU or the like, and includes a motion controller 2121, for example. The calculation unit 212 issues a drive command from the motion controller 2121 to the servo amplifier unit 41 included in the coordinate measuring machine 1. The servo amplifier 41 supplies electric power according to the received command to the actuator of the XYZ axis drive unit built in the coordinate measuring machine 1. In addition, the calculation unit 212 performs drive control based on feedback signals from the scale unit 19b and the tip sphere displacement detection unit 19a by the motion controller 2121 and further calculates a measurement value. The display control unit 213 controls the image displayed on the monitor 24. Note that the storage unit 211 stores a surface property measurement program for driving the coordinate measuring machine 1, a detection value detected by the measurement, a design value of the object to be measured, and the like. The calculation unit 212 reads the surface texture measurement program from the storage unit 211 and measures the shape of the object to be measured.

  The calculation unit 212 receives operator instruction information input from the keyboard 22 and the mouse 23 via the I / F (interface) 214. Further, the calculation unit 212 takes in the detected tip sphere displacement information and slider displacement information. Based on the input information, operator instruction information, and the program stored in the storage unit 211, the calculation unit 212 performs various processes such as movement of the slider 16 by the XYZ axis driving unit 18 and correction processing of measured values. To do. The calculation unit 212 outputs measurement values calculated by various processes to the printer 25 via an I / F (interface) 215. The I / F (interface) 216 is used to convert CAD data of the device under test 31 provided from an external CAD system (not shown) into a predetermined format and input it to the computer main body 21.

  Next, the scanning probe 101 will be described. FIG. 3 is a cross-sectional view of the scanning probe 101 in the XZ plane. The scanning probe 101 corresponds to the probe 17 in FIGS. The scanning probe 101 includes a probe housing 110, a probe main shaft 120, a probe main shaft support mechanism 130, a stylus module 160, and a detected portion 190. The probe housing 110 extends from the lower end of the slider 16 in the negative direction of the Z axis. A probe spindle support mechanism 130 is attached to the end of the probe housing 110 on the negative side of the Z axis. A stylus module 160 is attached to the end of the probe spindle support mechanism 130 on the negative side of the Z axis. The probe main shaft 120 is also simply referred to as a shaft member.

  Although FIG. 3 shows the XZ plane of the scanning probe 101, the scanning probe 101 has a configuration that is generally axisymmetric with respect to the Z axis. Therefore, the structure of the cross section in the plane parallel to the Z axis is substantially the same as FIG.

  The probe housing 110 is a member having a cylindrical shape. The central axis of the probe housing 110 is parallel to the Z axis. The probe housing 110 is fixed to the coordinate measuring machine 1. Specifically, it is joined to the lower end of the slider 16.

  The probe spindle support mechanism 130 includes an elastic support mechanism 140 and a joint portion 150. The probe spindle support mechanism 130 is also referred to as a probe support mechanism. The elastic support mechanism 140 includes a bellows end flange 141, a diaphragm 142, a bellows 143, a bellows end flange 144, and a diaphragm 145.

  The bellows end flange 141 is also referred to as a support member. The diaphragm 142 is also referred to as a first elastic member. The diaphragm 145 is also referred to as a second elastic member. The bellows 143 is also referred to as a third elastic member.

  The bellows end flange 141 is fixed to the end of the probe housing 110 on the negative side of the Z axis. The bellows end flange 141 has a donut-shaped flat disk shape having an opening at the center, and is attached to the probe housing 110 in a state where the main surface is perpendicular to the Z-axis.

  Diaphragm 142 is fixed on the Z-axis plus side surface of bellows end flange 141. An opening is provided in the center of the diaphragm 142. The probe main shaft 120 passes through the opening, and the diaphragm 142 supports the probe main shaft 120. The diaphragm 142 is an elastic member having a rigidity that allows displacement of the probe main shaft 120 in the Z-axis direction but does not allow displacement of the probe main shaft 120 in a direction perpendicular to the Z-axis (in the main surface of the diaphragm 142). Composed.

  Since the bellows end flange 141 is fixed to the probe housing 110, the displacement between the probe main shaft 120 and the diaphragm 142 in the direction perpendicular to the Z axis (in the main surface of the diaphragm 142) is limited to almost zero. The Therefore, the probe main shaft 120 can only move in the Z-axis direction and pivot about the joint between the probe main shaft 120 and the diaphragm 142 with respect to the diaphragm 142.

  The bellows 143 is an elastic member having an expandable bellows shape. In other words, the bellows 143 is a flexible elastic member that can expand and contract in the main axis direction. The bellows 143 has a structure in which thin annular plates of rolled metal are superposed and the inner and outer circumferences are alternately subjected to precision welding by laser. The bellows 143 has a very large surface area relative to the space volume occupied for mechanical integration. The end portion of the bellows 143 in the Z-axis plus direction is joined to the surface of the bellows end flange 141 on the minus side of the Z-axis. The end of the bellows 143 in the negative Z-axis direction is joined to the surface of the bellows end flange 144 on the positive Z-axis direction. That is, the bellows 143 is arrange | positioned so that expansion-contraction between the bellows end flange 141 and the bellows end flange 144 is possible.

  The diaphragm 145 is joined to the surface on the negative side of the Z-axis of the bellows end flange 144. An opening is provided in the center of the diaphragm 145. The probe main shaft 120 passes through the opening, and the diaphragm 145 supports the probe main shaft 120. The diaphragm 145 is configured by a member having rigidity that allows displacement of the probe main shaft 120 in the axial direction but does not allow displacement of the probe main shaft 120 in a direction perpendicular to the axial direction (in the main surface of the diaphragm 145). The

  Unlike the bellows end flange 141, the bellows end flange 144 is not fixed to the probe housing 110. Accordingly, following the pivot movement of the probe spindle 120, the joint between the probe spindle 120 and the diaphragm 145 can be displaced not only in the Z-axis direction but also in the X-axis direction and the Y-axis direction. .

  The joint unit 150 includes a joint disk 151, rollers 152, and permanent magnets 153. The joint disk 151 is joined to the surface on the negative side of the Z-axis of the bellows end flange 144 so as to cover the diaphragm 145. The Z-axis minus side end of the probe main shaft 120 is joined to the joint disk 151. Three rollers 152 are provided on the surface on the negative side of the Z-axis of the joint disk 151. A permanent magnet 153 is provided at the center of the Z-axis minus side surface of the joint disk 151.

  The stylus module 160 has a joint part 170 and a measuring element 180. The joint unit 170 includes a joint disk 171, a ball 172, and a suction plate 173. A ball 172 is provided on the surface of the joint disk 171 on the Z axis plus side. For example, two balls 172 are provided as a set. A suction plate 173 is provided in the center of the positive surface of the Z axis of the joint disk 171. The suction plate 173 is made of, for example, a member containing iron and is attracted by the permanent magnet 153. Thereby, the stylus module 160 is detachably attached to the probe spindle support mechanism 130.

  Here, the joining of the joint part 150 and the joint part 170 will be described. 4 is a cross-sectional view of main parts of joint portions 150 and 170 taken along line IV-IV shown in FIG. When the rollers 152 of the joint portion 170 are fitted into a set of two balls 172, the position of the joint portion 170 with respect to the joint portion 150 is determined.

  FIG. 5A is a plan view of the joint portion 150 when viewed from the A direction shown in FIG. 3. A direction shown in FIG. 3 is a direction from the minus side of the Z axis toward the plus side. Three rollers 152 are provided on the joint disk 151 so as to be spaced 120 degrees apart on a concentric circle with respect to the center of the joint disk 151. Each roller 152 is fitted with two balls 172 fixed to the joint disk 171. A permanent magnet 153 is fixed at the center of the joint disk 151.

  FIG. 5B is a plan view of the joint portion 170 when viewed from the B direction shown in FIG. 3. The direction B shown in FIG. 3 is a direction from the plus side to the minus side of the Z axis. Three pairs of two balls 172 are provided on the joint disk 171 at 120 ° intervals on a concentric circle with the center of the joint disk 171 as a reference. The roller 152 fixed to the joint disk 151 is fitted to each set of balls 172. A suction plate 173 is fixed at the center of the joint disk 171.

  Returning to FIG. 3, the configuration of the stylus module 160 will be described. The measuring element 180 includes a stylus shaft 181 and a contact 182. The Z axis plus side end of the stylus shaft 181 is joined to the Z axis minus side surface of the joint disk 171. A contact 182 that is in contact with the object to be measured is joined to the negative end of the Z-axis of the stylus shaft 181.

  The detected part 190 includes a reflecting mirror 191 and a reflecting mirror holder 192. The reflector holder 192 is fixed to the Z-axis plus side end of the probe main shaft 120. The reflecting mirror 191 is fixed to the Z-axis plus side end of the reflecting mirror holder 192. Although not shown, laser light is irradiated from a light source to the reflecting mirror 191 and reflected by the reflecting mirror 191. Then, when the light receiving unit receives the reflected light, the displacement of the reflecting mirror 191 is detected. The reflecting mirror 191 is connected to the contact 182 via the reflecting mirror holder 192, the probe main shaft 120, the joint portion 150, the joint portion 170, and the stylus shaft 181. Therefore, the coordinate measuring machine can detect the displacement of the contact 182 of the measuring element 180 by detecting the displacement of the reflecting mirror 191.

  Next, the configuration of the diaphragm 142 will be described. FIG. 6A is an overhead view when the diaphragm 142 is viewed from the Z-axis direction. The diaphragm 142 is made of a disk-shaped thin plate elastic material. The disk member 142A of the diaphragm 142 is disposed such that the main surface is perpendicular to the Z axis in a state where no load is applied to the contact 182. In the diaphragm 142, a circular opening 142B is formed in the center of the disk member 142A. The disk member 142A outside the opening 142B is provided with three punching grooves 142C. The three cutout grooves 142C have a substantially “<” shape formed of a straight portion and an arc portion, and are spaced apart by 120 ° with the opening 142B as the center.

  The disk member 142A between the opening 142B and the three extraction grooves 142C is fixed by being uniformly pressed against the tapered portion of the Z-axis plus side end of the probe main shaft 120. The disk member 142A outside the three punching grooves 142C is fixed by being pressed uniformly against the surface on the plus side of the Z-axis of the bellows end flange 141. The probe main shaft 120 passes through the opening 142B, and is supported by the diaphragm 142 by contacting the opening 142B.

  Next, the configuration of the diaphragm 145 will be described. FIG. 6B is an overhead view when the diaphragm 145 is viewed from the Z-axis direction. The diaphragm 145 has the same configuration as the diaphragm 142. The diaphragm 145 is made of a disk-shaped thin plate elastic material. The disk member 142A of the diaphragm 145 is disposed so that the main surface is perpendicular to the Z axis in a state where no load is applied to the contact 182. In the diaphragm 145, a circular opening 145B is formed at the center of the disk member 145A. In addition, the disk member 145A outside the opening 145B is provided with three hollows 145C. The three extraction grooves 145C have a substantially “<” shape formed of a straight line portion and an arc portion, and are spaced apart by 120 ° with the opening portion 145B as the center.

  A disk member 145A between the opening 145B and the three extraction grooves 145C is fixed by being uniformly pressed against the tapered portion of the Z-axis minus side end of the probe main shaft 120. The disk member 145A outside the three cutout grooves 145C is fixed by being uniformly pressed against the surface on the negative side of the Z-axis of the bellows end flange 144. The probe main shaft 120 passes through the opening 145B, and is supported by the diaphragm 145 by contacting the opening 145B.

  When the contact 182 is not loaded, the center of the diaphragm 142 (opening 142B) and the center of the diaphragm 145 (opening 145B) are aligned on the Z axis.

  Next, the operation of the scanning probe 101 at the time of scanning measurement will be described. A case where the contact 182 of the measuring element 180 comes into contact with the measurement target and is pushed in the positive direction of the Z axis will be described. FIG. 7A is a diagram schematically showing the movement of the scanning probe 101 when the contact 182 is pushed in the Z-axis plus direction. In FIG. 7A, the probe main shaft 120, the bellows end flange 141, the diaphragm 142, the bellows 143, the diaphragm 145, the stylus shaft 181 which are components necessary for understanding the operation of the scanning probe 101 are shown for simplification of the drawing. The contact 182 is displayed.

  In this case, the contact 182 receives the measuring force F1 in the positive direction of the Z axis, and the probe main shaft 120 is displaced in the positive direction of the Z axis. At this time, the probe main shaft 120 displaces the opening 142B of the diaphragm 142 and the opening 145B of the diaphragm 145 in the positive direction of the Z axis. Then, the probe main shaft 120 is displaced in the Z-axis plus direction, whereby the bellows 143 is compressed in the Z-axis direction. That is, the probe main shaft 120 is supported while the diaphragm 142, the diaphragm 145, and the bellows 143 are deformed.

  Next, the case where the contact 182 of the measuring element 180 comes into contact with the measurement target and is pushed in the direction perpendicular to the Z-axis direction (X direction, Y direction) will be described. FIG. 7B is a diagram schematically showing the movement of the scanning probe 101 when the contact 182 is pushed in a direction (X direction, Y direction) perpendicular to the Z-axis direction. In FIG. 7B, for the sake of simplification of the drawing, the components necessary for understanding the operation of the scanning probe 101 are the probe main shaft 120, the bellows end flange 141, the diaphragm 142, the bellows 143, the diaphragm 145, the stylus shaft 181; The contact 182 is displayed.

  In this case, the contact 182 receives a measuring force F2 in a direction perpendicular to the Z axis. As described above, the diaphragm 142 is fixed to the probe housing 110, and has a rigidity that does not allow displacement of the probe main shaft 120 in a direction perpendicular to the Z axis (in the main surface of the diaphragm 142). Therefore, the contact portion of the probe main shaft 120 with the opening 142B is not displaced in the direction perpendicular to the Z axis (X direction and Y direction).

  On the other hand, as described above, the diaphragm 145 is not fixed to the probe housing 110 and is connected to the bellows end flange 141 via the bellows 143. Therefore, the opening 145B of the diaphragm 145 can be displaced in the direction (X direction and Y direction) perpendicular to the Z axis by the above-described conical motion.

  Therefore, the probe main shaft 120 performs a conical motion accompanied by the bending of the bellows 143, with the center of the opening 142B on the Z-axis being the center of rotation. The bellows 143, the diaphragm 142, and the diaphragm 145 are parts made of an elastic material, and have a flexible spring constant that allows displacement due to conical movement of the contact portion of the probe main shaft 120 to the diaphragm 145 and displacement in the Z-axis direction. . Note that the bellows 143 has high rigidity with respect to torsion around the main axis of the bellows 143. Therefore, even if the bellows 143 is bent by conical motion, the rotational motion around the main axis does not occur. Therefore, the measurement result of the scanning probe 101 is not mixed with an error due to the rotational motion around the main axis of the bellows 143.

  According to this configuration, the scanning probe 101 supports the probe main shaft 120 by the diaphragm 142, the diaphragm 145, and the bellows 143 that are elastic members. Therefore, propagation of vibration (that is, disturbance) can be prevented or alleviated by the elastic member via the bellows end flange 141 fixed to the slider 16. Therefore, according to this configuration, it is possible to prevent or alleviate the propagation of disturbance transmitted to the probe 180, and to suppress deterioration in measurement accuracy due to disturbance caused by measurement operation or non-linear disturbance.

  According to this configuration, the diaphragm 145 on the contact 182 side has a greater degree of freedom of movement than the diaphragm 142 on the detected portion 190 side, and is displaced in the direction perpendicular to the Z axis (X direction and Y direction). It is possible. Therefore, even when the pushing amount in the direction perpendicular to the Z axis (X direction and Y direction) is large, the contact 182 can follow the shape of the measurement object.

  Therefore, according to this configuration, it is possible to perform surface shape measurement with a large unevenness or a complicated shape as compared with the case where the diaphragm 145 on the contact 182 side is fixed. Therefore, according to this configuration, more advanced shape measurement can be realized.

Embodiment 2
Next, the scanning probe 201 according to the second embodiment will be described. The scanning probe 201 corresponds to the probe 17 in FIGS. FIG. 8 is a cross-sectional view of the scanning probe 201 in the XZ plane. The scanning probe 201 has a configuration in which the probe spindle support mechanism 130 of the scanning probe 101 is replaced with a probe spindle support mechanism 230. The probe spindle support mechanism 230 has a configuration in which the elastic support mechanism 140 of the probe spindle support mechanism 130 is replaced with an elastic support mechanism 240.

  In FIG. 8, the XZ plane of the scanning probe 201 is shown, but the scanning probe 201 has a substantially axially symmetric configuration with respect to the Z axis. Therefore, the structure of the cross section in the plane parallel to the Z axis is substantially the same as FIG.

  The elastic support mechanism 240 has a configuration in which a bellows 146 is added to the elastic support mechanism 140. The bellows 146 is also referred to as a fourth elastic member. The bellows 146 is an elastic member having a bellows shape that has a smaller inner diameter than the bellows 143 and can be expanded and contracted. In other words, the bellows 146 is a flexible elastic member that can expand and contract in the main axis direction. The bellows 146 has a structure in which thin annular plates of rolled metal are superposed and the inner and outer circumferences are alternately subjected to precision welding by laser. Bellows 146 has a very large surface area relative to the space volume it occupies for mechanical integration.

  The bellows 146 is disposed between the bellows end flange 141 and the bellows end flange 144 so as to be surrounded by the bellows 143. The end of the bellows 146 in the positive Z-axis direction is joined to the end of the bellows end flange 141 on the negative side of the Z-axis. The end of the bellows 146 in the negative Z-axis direction is joined to the end of the bellows end flange 144 on the positive side of the Z-axis. That is, the bellows 146 is disposed between the bellows end flange 141 and the bellows end flange 144 so as to be extendable and contractible.

  By arranging the bellows 146 as described above, the bellows 143 and the bellows 146 constitute a double bellows 147. A sealed space exists between the bellows 143 and the bellows 146. Incompressible viscous fluid 148A and gas 148B are enclosed in this space. The incompressible viscous fluid 148A is typically a liquid, and uses a fluid that has negligible compressibility and expandability compared to the gas 148B. For example, various mineral oils can be used for the incompressible viscous fluid 148A. A gas such as air or nitrogen can be used as the gas 148B.

  Since the incompressible viscous fluid 148A is enclosed in a sealed space, it flows without leaking to the outside regardless of the bending state of the double bellows 147. In addition, since the incompressible viscous fluid 148A is isolated from the external atmosphere, it is possible to prevent deterioration of the incompressible viscous fluid 148A over time.

  Since the other configuration of the scanning probe 201 is the same as that of the scanning probe 101, the description thereof is omitted.

  Next, the operation of the scanning probe 201 will be described. For example, when the contact 182 is in contact with the measurement object, or when the scanning probe 201 is accelerated or travels normally, if driving vibration is applied to the scanning probe 201, the probe spindle 120 is displaced. As described above, in the scanning probe 201, the incompressible viscous fluid 148A is enclosed between the two bellows 143 and the bellows 146 of the double bellows 147. Therefore, when the displacement of the probe main shaft 120 due to the drive vibration occurs, the incompressible viscous fluid 148 </ b> A flows and resistance against the bending of the double bellows 147 occurs. The flow resistance of the incompressible viscous fluid 148A increases in proportion to the wall surface area of the solid (bellows 143, bellows 146) involved in the flow and the flow velocity of the incompressible viscous fluid 148A along the wall surface. .

  Therefore, when vibration from the outside of the coordinate measuring machine 1 or the driving vibration described above is applied as a disturbance to the scanning probe 201, the flow resistance of the incompressible viscous fluid 148A causes the object 31 of the probe 180 to be measured. It is possible to attenuate an unnecessary displacement (vibration amplitude) of the probe main shaft 120 which is an error caused by vibration acceleration, which is different from the displacement caused by the contact.

  In general, in a coordinate measuring machine, vibration is applied to the probe in an environment where high-speed driving of the probe or acceleration / deceleration motion having a large acceleration is performed. However, according to this configuration, it is possible to prevent the occurrence of errors in the shape measurement of the coordinate measuring machine due to disturbances such as vibrations from the outside of the coordinate measuring machine and the drive vibration described above. Further, the force damping effect due to the fluid resistance of the viscous fluid is not accompanied by hysteresis. Therefore, measurement errors due to hysteresis can be prevented. As a result, it is possible to achieve high measurement accuracy even in an environment where high-speed driving of the probe and acceleration / deceleration motion with large acceleration are performed.

Embodiment 3
Next, the scanning probe 301 according to the third embodiment will be described. The scanning probe 301 corresponds to the probe 17 in FIGS. FIG. 9 is a cross-sectional view of the scanning probe 301 in the XZ plane. The scanning probe 301 is a modification of the scanning probe 201. In the scanning probe 301, the pressure of the gas 148B enclosed in the double bellows 147 is variable.

  The scanning probe 301 has a configuration in which the probe spindle support mechanism 230 of the scanning probe 201 is replaced with a probe spindle support mechanism 330. The probe spindle support mechanism 330 has a configuration in which the elastic support mechanism 240 of the probe spindle support mechanism 230 is replaced with an elastic support mechanism 340.

  Although FIG. 9 shows the XZ plane of the scanning probe 301, the scanning probe 301 has a configuration that is generally axisymmetric with respect to the Z axis. Therefore, the structure of the cross section in the plane parallel to the Z axis is substantially the same as FIG.

  The elastic support mechanism 340 has a configuration in which the bellows end flange 141 of the elastic support mechanism 240 is replaced with a bellows end flange 341. The bellows end flange 341 was perforated between an opening 342A provided in a space in which the gas 148B of the double bellows 147 was sealed and an opening 342B provided on the outer side surface of the bellows end flange 341. A tube portion 342C is provided.

  A pressure adjustment device 310 is provided outside the scanning probe 301. The pressure adjustment device 310 may be incorporated in the coordinate measuring machine 1 or may be provided outside the coordinate measuring machine 1. The pressure adjusting device 310 is connected to the opening 342 </ b> B through the gas pipe 311, and receives a command from the computer 2 to control the pressure of the gas 148 </ b> B inside the double bellows 147.

  Since the other configuration of the scanning probe 301 is the same as that of the scanning probe 201, the description thereof is omitted.

  Next, the operation of the scanning probe 301 will be described. As described above, in the scanning probe 301, the pressure of the gas 148 </ b> B inside the double bellows 147 can be adjusted by a command from the computer 2.

  If the pressure of the gas 148B in the double bellows 147 is increased, the air spring constant ka of the gas 148B is added to the spring constant kb of the double bellows 147 itself. Therefore, when it sees as the whole elastic support mechanism 340, the spring constant which acts on the probe main axis | shaft 120 can be enlarged. That is, by increasing the pressure of the gas 148B in the double bellows 147, the natural frequency of the scanning probe 301 determined by the mass of the movable portion of the scanning probe 301 and the spring constant can be set high.

  On the other hand, if the pressure of the gas 148B in the double bellows 147 is lowered, the internal pressure of the gas 148B is balanced with the atmospheric pressure if the pressure of the gas 148B is made equal to the atmospheric pressure, and the conditions are the same as those of the scanning probe 201. That is, the minimum value of the spring constant of the elastic support mechanism 340 is the spring constant kb of the double bellows 147 itself.

  In general, in a CMM, in order to achieve higher measurement accuracy and improved control performance in an environment where the probe is driven at high speed and acceleration / deceleration movement with large acceleration is performed, the natural frequency of the CMM can be increased. Need to set high. On the other hand, a probe attached to a coordinate measuring machine having a high natural frequency needs to avoid resonance with the coordinate measuring machine main body.

  FIG. 10 shows a relative displacement related to the vibration amplitude between the slider 16 and the movable portion of the scanning probe 301 when a probe having an arbitrary natural frequency is mounted on a CMM having a natural frequency of 60 Hz. It is a graph which shows a magnification. In FIG. 10, the horizontal axis indicates the natural frequency of the probe mounted on the coordinate measuring machine, and the vertical axis indicates the relative displacement magnification between the slider 16 and the movable portion of the scanning probe 301. In the graph, ζ represents an attenuation ratio of the scanning probe 301.

  When a natural frequency is 60 Hz and a probe with a damping ratio ζ of 0.15 is attached, the relative displacement magnification that is a measurement error exceeds three times. On the other hand, when a probe with an attenuation ratio ζ of 0.5 is attached, the relative displacement magnification approaches one. In this configuration, by injecting the incompressible viscous fluid 148A into the double bellows 147, attenuation without hysteresis is provided, and the relative displacement magnification that becomes a measurement error can be kept small. As a result, improvement in measurement accuracy can be realized. However, if the attenuation ratio ζ is improperly large, the followability of the probe is deteriorated when performing a scanning measurement with a coordinate measuring machine. Therefore, it is desirable to set the attenuation ratio in consideration of the followability.

  On the other hand, when performing deep hole measurement or the like, a long and large measuring element is used. For this reason, an increase in the inertial mass of the probe applied to the movable part of the probe may reduce the natural frequency of the probe, which may approach a resonance state with the three-dimensional measuring machine 1 main body. When the probe spindle 120 performs a conical motion by contact with a measurement object like the scanning probe 301, if a long probe is attached while the spring constant of the elastic support mechanism 340 is the same, the probe becomes longer as a result of the lever principle. The measuring force at the contact 182 is reduced. Therefore, the spring constant of the elastic support mechanism must be changed according to the length of the probe. If the spring constant of the elastic support mechanism cannot be adjusted, it is necessary to replace the elastic support mechanism in accordance with the measuring element.

  However, in this configuration, since the spring constant of the elastic support mechanism 340 can be set high, it is possible to compensate for a decrease in measuring force due to the length of the probe. Thereby, it becomes possible to mount measuring elements of various lengths without exchanging the elastic support mechanism. As a result, replacement of the measuring element is facilitated, and a situation where a plurality of elastic support mechanisms having different spring constants must be prepared can be avoided.

Other Embodiments The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention. For example, in the scanning probe 101 according to the first embodiment, the case where the bellows 143 is used has been described. However, the bellows 143 can be replaced with another elastic member. For example, the bellows 143 can be replaced with a coil spring. The coil spring has a stronger rotational force around the main shaft in response to expansion and contraction than the bellows, but is sufficiently applicable in a measurement environment where measurement accuracy can be relaxed. For example, the bellows 143 can be replaced with a triple spring. Here, the three-row spring has a structure in which three normal springs, machined springs made by machining, and the like are rotated by 120 ° with respect to the main shaft. Compared with a single coil spring, the triple spring cancels the rotational force around the main shaft according to expansion and contraction, and can reduce anisotropy that affects measurement accuracy.

  The bellows 143 can be replaced with a plurality of bellows. In this case, by arranging a plurality of bellows at equal intervals around the probe main shaft 120 between the bellows end flange 141 and the bellows end flange 144, the diaphragm 145 is similar to the scanning probe 101 with respect to the diaphragm 142. It is possible to perform exercises.

  Further, the double bellows 147 can be replaced with a plurality of double bellows. In this case, a plurality of double bellows are arranged at equal intervals around the probe main shaft 120 between the bellows end flange 141 and the bellows end flange 144, so that the diaphragm 145 and the probe 142 follow the scanning probe 201. Alternatively, it is possible to perform an exercise similar to 301.

  In the above-described embodiment, the diaphragm 145 allows the displacement of the probe main shaft 120 in the axial direction, but does not allow the displacement of the probe main shaft 120 in the direction perpendicular to the axial direction (in the main surface of the diaphragm 145). Although described as a member having rigidity, this is merely an example. For example, if the displacement of the probe spindle 120 in the axial direction can be allowed, the diaphragm is replaced with a diaphragm having rigidity sufficient to allow displacement of the probe spindle 120 in the direction perpendicular to the axial direction (in the principal surface of the diaphragm 145). Is also possible.

DESCRIPTION OF SYMBOLS 1 CMM 2 Computer 3 Cable 10 Isolation table 11 Surface plate 12a Beam support 12b Beam support 13 Beam 14 Y-axis drive mechanism 15 Column 16 Slider 17 Probe 17a Tip sphere 17b Stylus 18 XYZ-axis drive 19a Tip sphere Displacement detection unit 19b Scale unit 19bx X-axis scale unit 19by Y-axis scale unit 19bz Z-axis scale unit 21 Computer main body 22 Keyboard 23 Mouse 24 Monitor 25 Printer 31 Device under test 41 Servo amplifier 100 Shape measuring device 101, 201, 301 Copy probe 110 Probe housing 120 Probe spindle 130, 230, 330 Probe spindle support mechanism 140, 240, 340 Elastic support mechanism 141, 144, 341 Bellows end flange 142, 145 Diaphragm 142A, 145A Disk member 142B, 145B Opening 142C, 145C Ditch groove 143, 146 Bellows 147 Double bellows 148A Incompressible viscous fluid 148B Gas 150 Joint portion 151, 171 Joint disk 152 Roller 153 Permanent magnet 160 Stylus module 170 Joint 171 Joint disk 172 Ball 173 Suction plate 180 Measuring element 181 Stylus shaft 182 Contactor 190 Detected part 191 Reflecting mirror 192 Reflecting mirror holder 211 Storage part 212 Calculation part 213 Display control part 213 to 216 I / F
310 Pressure adjustment device 311 Gas piping 342A, 342B Opening 342C Pipe 2121 Motion controller

Claims (15)

A shaft member having a first direction as an axis in a situation where a probe can be attached to the tip and no load is applied to the probe,
The shaft member is inserted and has elasticity to allow displacement of the shaft member in the first direction and to prevent displacement of the shaft member in a plane perpendicular to the first direction. A first elastic member;
A second elastic member that is inserted through the shaft member and allows displacement of the shaft member in the axial direction of the shaft member;
A third elastic member that is extendable and flexible and connects the first elastic member and the second elastic member;
Probe support mechanism. The third elastic member is disposed so as to surround the shaft member between the first elastic member and the second elastic member.
The probe support mechanism according to claim 1. The third elastic member is a bellows having one end joined to the first elastic member via a first flange and the other end joined to the second elastic member via a second flange. ,
The measuring element support mechanism according to claim 1 or 2. The third elastic member seals a space between the shaft member and the third elastic member between the first elastic member and the second elastic member;
The probe support mechanism according to claim 3. A fourth elastic member that is extendable and flexible and connects the first elastic member and the second elastic member;
The fourth elastic member is
Between the first elastic member and the second elastic member, and disposed so as to surround the shaft member between the third elastic member and the shaft member; and Sealing a space between the fourth elastic member;
The probe support mechanism according to claim 4. The fourth elastic member has one end joined to the first elastic member via the first flange and the other end joined to the second elastic member via the second flange. Is,
The probe support mechanism according to claim 5. An incompressible viscous fluid partially filled in the space between the third elastic member and the fourth elastic member;
Of the space between the third elastic member and the fourth elastic member, further comprising a gas said incompressible viscous fluid fills the are not already partially filled,
The probe support mechanism according to claim 5 or 6. The gas is adjustable in pressure,
The probe support mechanism according to claim 7. A first flange fixed to the external member;
Said first flange is provided with the space between the third elastic member and the fourth elastic member, and the outside of the measuring element support mechanism, a tube portion which connects,
The pressure of the gas is adjusted by a pressure adjusting device outside the probe support mechanism via the tube portion.
The probe support mechanism according to claim 8. The third elastic member is a coil spring having one end joined to the first elastic member via a first flange and the other end joined to the second elastic member via a second flange. is there,
The measuring element support mechanism according to claim 1 or 2. The third elastic member is a triple spring having one end joined to the first elastic member via a first flange and the other end joined to the second elastic member via a second flange. is there,
The measuring element support mechanism according to claim 1 or 2. The first elastic member and the second elastic member are diaphragms composed of a disk-shaped elastic member through which the shaft member is inserted into an opening provided in the center.
The probe support mechanism according to any one of claims 1 to 11. The second elastic member has elasticity that allows displacement of the shaft member in the axial direction of the shaft member and prevents displacement of the shaft member in a plane perpendicular to the axial direction of the shaft member. Have
The probe support mechanism according to any one of claims 1 to 12. The second elastic member has elasticity that allows displacement of the shaft member in the axial direction of the shaft member and allows displacement of the shaft member in a plane perpendicular to the axial direction of the shaft member. Have
The probe support mechanism according to any one of claims 1 to 12. A probe that contacts the measurement object;
A shaft member having the first direction as an axis in a situation in which a load is not applied to the probe;
The shaft member is inserted and has elasticity to allow displacement of the shaft member in the first direction and to prevent displacement of the shaft member in a plane perpendicular to the first direction. A first elastic member;
A second elastic member that is inserted through the shaft member and allows displacement of the shaft member in the axial direction of the shaft member;
A third elastic member that is extendable and flexible and connects the first elastic member and the second elastic member;
probe.

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