JP7565488B2 - Shape measuring instrument and measuring force adjustment method - Google Patents

Description

The present invention relates to a shape measuring instrument that measures the shape of an object to be measured and a method for adjusting the measuring force.

There is known a shape measuring machine that measures the surface roughness and shape of the object, such as the outline, by moving a detector equipped with a measuring element along the surface of the object, converting the amount of displacement of the tip of the measuring element into an electrical signal and reading it into a processing device such as a computer. In a shape measuring machine, a stylus equipped with a measuring element at its tip is biased to bring the stylus at the tip of the measuring element into contact with the surface of the part to be measured.

In conventional detectors that do not have a mechanism for adjusting the measuring force, the measuring force depends on the mass and length of the stylus. This means that when the stylus is replaced, the measuring force changes before and after the stylus replacement. In addition, because conventional detectors do not have a mechanism for measuring the measuring force, a separate load gauge or the like must be prepared when measuring the measuring force.

Patent Document 1 describes a surface-following measuring instrument equipped with a measuring force detection means for detecting the measuring force applied to the measuring probe. The surface-following measuring instrument described in the same document is equipped with a measuring force detection means for detecting the measuring force in addition to a displacement detection means for detecting the amount of displacement of the tip of the measuring probe. The measuring force detection means detects the measuring force based on the detection signal of a strain gauge.

Patent Document 2 describes a surface-following measuring machine equipped with a means for detecting the measuring force. The surface-following measuring machine described in this document has a piezoelectric element inserted between the stylus and the contact needle, and detects the measuring force based on the output voltage of the piezoelectric element.

Patent No. 3273026 Patent No. 5009564

However, both of the surface tracking measuring instruments described in Patent Document 1 and Patent Document 2 are equipped with a mechanism for detecting the measuring force in addition to the mechanism for detecting the amount of displacement of the tip of the measuring probe. This leads to problems such as increased costs due to the larger size of the detector and the more complex circuitry for processing the detection signals.

The present invention was made in consideration of these circumstances, and aims to provide a shape measuring instrument that can measure the measuring force using a sensor that measures the amount of displacement at the tip of the measuring probe.

To achieve the above objective, the following aspects of the invention are provided:

The shape measuring machine according to the first aspect is a shape measuring machine that measures the shape of an object to be measured by moving a measuring probe provided at the tip side of a first arm rotatably supported by a rotation fulcrum relative to the object to be measured, and is equipped with a sensor attached to the first arm and outputting a detection signal corresponding to the displacement of the measuring probe, a measuring force applying unit that biases the first arm in the rotation direction of the first arm to apply a measuring force to the measuring probe, a second arm that is connected to the first arm at a position on the base end side of the first arm relative to the mounting position of the sensor on the first arm, a regulating unit that regulates the rotation of the second arm connected to the first arm when the first arm is biased, a memory unit that regulates the position of the second arm using the regulating unit and stores the relationship between the reference measuring force derived when the first arm is biased to deflect the second arm and the detection value of the sensor, a measuring force calculation unit that refers to the memory unit and calculates the measuring force of the object to be measured based on the detection value of the sensor, and a measuring force information output unit that outputs information on the measuring force of the object to be measured calculated using the measuring force calculation unit.

According to the first aspect, the position of the second arm is regulated, and the detection signal of the sensor is acquired while the second arm is bent. With reference to the relationship between the reference measurement force and the detection value of the sensor, the measurement force of the measurement object applied to the measurement probe is calculated from the detection value of the sensor that detects the displacement amount of the measurement probe, and information on the measurement force of the measurement object is output. In this way, the measurement force applied to the measurement probe can be measured using the sensor that detects the displacement amount of the measurement probe.

An example of a probe configuration is one that includes a probe that is brought into contact with the object to be measured, and a stylus to which the probe is attached.

An example of the sensor configuration is one that includes a mover that is attached to a first arm and moves in response to the displacement of the first arm, and an electrical signal conversion unit that converts the displacement of the mover into an electrical signal.

In a second aspect, in the shape measuring machine of the first aspect, the tip of the second arm may be connected to the base end of the first arm, and the restricting part may be arranged in a position that restricts the base end of the second arm.

In the second embodiment, a regulating part may be disposed at the end of the movement range of the probe to regulate the position of the second arm when the first arm is stopped.

In a third aspect, in the shape measuring machine of the first or second aspect, the sensor may be attached to a position closer to the base end of the first arm than the position of the rotation fulcrum of the first arm.

According to the third aspect, the sensor can output a detection signal according to the amount of displacement of the base end position of the first arm.

In a fourth aspect, in a shape measuring machine according to any one of the first to third aspects, the sensor may be a differential transformer type sensor.

According to the fourth aspect, the displacement of the probe can be converted into an electrical signal using a differential transformer type sensor.

In a fifth aspect, in the shape measuring machine of any one of the first to fourth aspects, the regulating unit may be configured to include a stopper member that contacts the second arm to regulate the position of the second arm.

According to the fifth aspect, the position of the second arm can be regulated by contacting the second arm with the stopper member.

In a sixth aspect, in the shape measuring machine of the first aspect, the sensor may be a scale-type sensor attached to a position closer to the tip of the first arm than the position of the rotation fulcrum of the first arm.

According to the sixth aspect, a scale-type sensor can be used to output a detection signal corresponding to the deflection of the second arm.

In a seventh aspect, in the shape measuring machine of the sixth aspect, the second arm may be connected to the first arm via an attachment member that is connected between the scale-type sensor on the first arm and the rotation fulcrum.

In the seventh aspect, it is preferable for the mounting member to have the same rigidity as the first arm. The mounting member may be made of the same material.

In an eighth aspect, in the shape measuring machine of the seventh aspect, the second arm may be arranged along a direction from the mounting member toward the tip side of the first arm, and the restricting portion may be arranged in a position that restricts the tip of the second arm.

In the eighth embodiment, the first arm and the second arm may be arranged in parallel.

Parallel may include non-parallel but essentially parallel, which can be considered parallel.

In a ninth aspect, in a shape measuring instrument according to any one of the first to eighth aspects, a display unit is provided that displays the measuring force of the object to be measured calculated using the measuring force calculation unit, and the measuring force information output unit may be configured to output information on the measuring force of the object to the display unit.

According to the ninth aspect, the operator or the like can understand the measurement force displayed on the display unit.

In the tenth aspect, the shape measuring instrument of the ninth aspect may be configured to include a measuring force adjustment unit that adjusts the measuring force applied to the probe based on the measuring force measured using the measuring force calculation unit.

According to the tenth aspect, the measurement force can be adjusted to a target measurement force.

According to the present invention, the position of the second arm is regulated, and the detection signal of the sensor is acquired while the second arm is bent. With reference to the relationship between the reference measurement force and the detection value of the sensor, the measurement force applied to the probe is calculated from the detection value of the sensor that detects the amount of displacement of the probe, and information on the measurement force is output. In this way, the measurement force applied to the probe can be measured using the sensor that detects the amount of displacement of the probe.

FIG. 1 is a diagram showing the overall configuration of a roughness measuring instrument. FIG. 2 is a schematic diagram of the gauge head and the displacement detector. FIG. 3 is a schematic diagram of the reference measuring force measurement. FIG. 4 is a schematic diagram of the measurement of the lower detection limit. FIG. 5 is a graph showing the relationship between the lower limit detection value and the measuring force. FIG. 6 is a block diagram showing an example of the configuration of the signal processing unit. FIG. 7 is a flow chart showing the steps of the measuring force adjustment method when the stylus is replaced. FIG. 8 is a schematic diagram showing the configuration of a displacement detector according to a modified example of the stopper. FIG. 9 is a schematic diagram showing the configuration of a displacement detector according to a modified example of the sensor.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings. In this specification, the same components as those previously described will be designated by the same reference numerals, and the description will be omitted as appropriate.

[Overall configuration of roughness measuring instrument]
Fig. 1 is an overall configuration diagram of a roughness measuring instrument. The roughness measuring instrument 10 shown in the figure comprises a surface plate 12, a support 14, an X-axis drive unit 16, a displacement detector 18, a probe 20, an input device 22, and a display device 24. The roughness measuring instrument 10 also comprises a control device (not shown). Reference numeral 52 shown in Fig. 1 denotes an engagement mechanism. The roughness measuring instrument 10 corresponds to an example of a form measuring instrument.

The workpiece to be measured is placed on the surface plate 12. The surface of the surface plate 12 on which the workpiece is placed is an XY plane parallel to the X-axis direction and the Y-axis direction. Support columns 14 extending in the Z-axis direction are erected on the surface plate 12.

The X-axis drive unit 16 is attached to the support 14 so that it can move freely in the Z-axis direction. The X-axis drive unit 16 is attached to a displacement detector 18 so that it can move freely in the X-axis direction. The displacement detector 18 is attached to a probe 20 so that it can be attached and detached freely.

The input device 22 transmits signals representing instructions to the control device. FIG. 1 illustrates a keyboard as the input device 22. The display device 24 displays the measurement results, etc., represented by the display signal transmitted from the control device.

The control device (not shown) is connected to the input device 22 via a specified interface. The control device is also connected to the display device 24 via a specified interface. The control device may be a computer. That is, the control device may include a processor, a memory, a storage device, and an input/output controller.

[Configuration of the Displacement Detector]
Fig. 2 is a schematic diagram of the gauge head and the displacement detector. The displacement detector 18 shown in Fig. 2 includes a detection arm 42, a stylus 44, and a differential transformer type sensor 46. The detection arm 42 is rotatably supported by an arm rotation fulcrum 40 that is engaged with a housing 48. Note that Fig. 2 shows the housing 48 in a schematic manner.

The arrow in FIG. 2 indicates the direction of rotation of the detection arm 42. The detection arm 42 is an example of a first arm.

The tip 42A of the detection arm 42 is connected to the base end 44B of the stylus 44. The detection arm 42 and the stylus 44 are connected using the engagement mechanism 52 shown in FIG. 1. The engagement mechanism 52 is not shown in FIG. 2.

In this specification, the tip portion refers to an area that is a certain distance from the tip. In this specification, the base end portion refers to an area that is a certain distance from the base end. An example of a certain distance is a distance of less than one-quarter of the total length. The tip may be the end on the stylus 50 side. The base end may be the end opposite the tip.

A contact needle 50 is attached to the tip 44A of the stylus 44. The stylus 44 and the contact needle 50 constitute the probe 20 shown in Figure 1.

The displacement detector 18 includes a biasing member 54 and a measuring force adjustment mechanism 56. In FIG. 2, a coil spring is illustrated as the biasing member 54. One end of the biasing member 54 is attached to the detection arm 42. The other end of the biasing member 54 is attached to the measuring force adjustment mechanism 56. The biasing member 54 corresponds to an example of a measuring force application section.

The measuring force adjustment mechanism 56 is a mechanism that varies the amount of extension of the biasing member 54 attached to the detection arm 42. The measuring force adjustment mechanism 56 varies the tension of the biasing member 54 to vary the measuring force.

The measuring force adjustment mechanism 56 may include a lifting mechanism that raises and lowers the base end position of the biasing member 54, and a motor that drives the lifting mechanism. The measuring force adjustment mechanism 56 may include a linear actuator that integrates the lifting mechanism and the motor. The motor and the linear actuator may be controlled based on a command signal transmitted from the control device. The measuring force adjustment mechanism 56 corresponds to an example of a measuring force adjustment unit.

The displacement detector 18 includes a detector arm 60 and a stopper 62. The detector arm 60 is connected to the base end 42B of the detection arm 42. The stopper 62 is positioned so that it comes into contact with the unbent detector arm 60 when the stylus 44 is lowered to its lowest position. The detector arm 60 corresponds to an example of a second arm. The stopper 62 corresponds to an example of a regulating portion and an example of a stopper member.

[Surface roughness measurement]
When measuring the surface roughness of a workpiece using the roughness measuring instrument 10, the probe 50, to which a certain measuring force is applied, is brought into contact with the surface of the workpiece placed on the surface plate 12. In this state, the probe 20 is moved along the X-axis direction using the X-axis drive unit 16. The probe 50 is displaced in the Z-axis direction according to the shape of the workpiece surface. The displacement detector 18 outputs an electrical signal according to the displacement of the probe 50.

The control device (not shown) calculates the measurement value of the surface roughness of the workpiece based on the electrical signal output from the displacement detector 18. The control device can display the measurement value using the display device 24. The display device 24 corresponds to an example of a display unit.

[Derivation of the relationship between the reference measuring force and the lower limit detection value]
The relationship between the reference measuring force F ₀ and the lower limit detection value D _t is derived according to the following procedure. The reference measuring force F ₀ is measured using a reference stylus 44. The reference stylus 44 may be any stylus 44, such as the stylus 44 that is most frequently used.

[Measurement of reference measuring force F0 _]
Fig. 3 is a schematic diagram of measuring the measuring force. As shown in Fig. 3, the load at the tip of the stylus 50 is measured using a load meter 70 while the detector arm 60 and the stopper 62 are in a non-contact state. The measured value of the load meter converted into a force is the reference measuring force _F0 .

The reference measuring force F ₀ may be measured when the detector arm 60 is in contact with the stopper 62 and the detector arm 60 is not deflected.

₃ indicates the overall length of the stylus 44 used to measure the reference measuring force F _0. The overall length of the stylus 44 refers to the distance from the attachment position of the contact needle 50 of the stylus 44 to the arm rotation fulcrum 40. The same applies to the overall length of any stylus 44 described later.

[Measurement of the lower detection limit]
4 is a schematic diagram of the measurement of the lower limit detection value Dt. The lower limit detection value _Dt is the detection value of the differential transformer type sensor 46 when the stylus 44 is in the lower limit position.

After measuring the reference measuring force _F0 , the stylus 44 is moved to its lower limit position. The detector arm 60 hits the stopper 62 and bends in response to the reference measuring force _F0 . The detection value of the differential transformer sensor 46 changes in response to the amount of bending of the detector arm 60. The detection value of the differential transformer sensor 46 in this state is set as the lower limit detection value _Dt . The reference measuring force _F0 and the lower limit detection value _Dt are stored as measurement data.

Next, the reference measuring force _F0 is changed using the measuring force adjustment mechanism 56. The reference measuring force _F0 is measured using a load meter 70 as shown in Fig. 3. Thereafter, the stylus 44 is moved to its lower limit position and a lower limit detection value _Dt is measured. The reference measuring force _F0 and the lower limit detection value _Dt are stored as measurement data.

This procedure is repeated to obtain and store a specified number of measurement data of the reference measuring force _F0 and the lower limit detection value _Dt . In deriving the relationship between the specified number of reference measuring forces _F0 and the lower limit detection value _Dt , an integer of 3 or more is applied as the specified number.

The dashed double-dashed line in FIG. 4 represents the state in which the detector arm 60 is in contact with the stopper 62 and is not bent when the stylus 44 is lowered to its lowest position.

The solid line in FIG. 4 indicates the state in which the detector arm 60 is in contact with the stopper 62 and is bent when the stylus 44 is lowered to its lowest position. Note that in FIG. 4, the reference numerals 42A, 42B, 44A, and 44B shown in FIG. 2 and FIG. 3 are omitted.

5 is a graph showing the relationship between the measuring force and the lower limit detection value. Reference numerals 100, 102, 104, 106, 108, and 110 shown in FIG. 5 represent the lower limit detection value _Dt for each reference measuring force _F0 .

As shown in Fig. 5, a straight line 112 showing the relationship between the reference measuring force _F0 and the lower limit detection value _Dt is derived using the measurement data of the lower limit detection value _Dt for each reference measuring force _F0 . Instead of the straight line 112 shown in Fig. 5, a table of the reference measuring force _F0 with the lower limit detection value _Dt as a parameter may be derived, or a function of the reference measuring force _F0 with the lower limit detection value _Dt as a parameter may be derived.

[Configuration of the signal processing section]
Fig. 6 is a block diagram showing an example of the configuration of a signal processing unit. The relationship between the reference measuring force _F0 and the lower limit detection value _Dt shown in Fig. 5 can be derived and stored using a signal processing unit 200 shown in Fig. 6. The signal processing unit 200 corresponds to an example of a measuring force calculation unit.

The signal processing unit 200 includes a sensor signal input unit 202, a measuring force input unit 204, a calculation unit 206, a memory unit 208, and an output unit 210. The sensor signal input unit 202 acquires a sensor signal representing a detection value from the differential transformer type sensor 46. The sensor signal input unit 202 can be an electrical circuit capable of inputting the sensor signal output from the differential transformer type sensor 46.

The measuring force input unit 204 acquires an electrical signal representing the reference measuring force F _0. The measuring force input unit 204 can be an electrical circuit capable of inputting a signal representing the reference measuring force F _0. The calculation unit 206 processes the sensor signal and the electrical signal representing the reference measuring force F ₀ to derive, for example, a relationship between the reference measuring force F ₀ and the lower limit detection value D _t, such as the straight line 112 shown in FIG. 5 .

The calculation unit 206 can refer to the relationship between the reference measuring force _F0 and the lower limit detection value _Dt , and derive the measuring force F of the object to be measured using the detection value of the differential transformer sensor 46 according to the amount of deflection of the detector arm 60. The calculation unit 206 may include a derivation processing unit that derives the relationship between the reference measuring force _F0 and the lower limit detection value _Dt , and a measuring force calculation unit that calculates the measuring force F of the object to be measured. The calculation unit 206 corresponds to an example of a component of the measuring force calculation unit.

The calculation unit 206 can be configured to include a processor such as a CPU (Central Processing Unit) and a memory such as a RAM (Random Access Memory).

The storage unit 208 stores the relationship between the reference measuring force _F0 and the lower limit detection value _Dt derived using the calculation unit 206. The storage unit 208 can be a storage element that non-temporarily stores various data, such as a semiconductor memory.

The output unit 210 outputs information on the measuring force F of the measurement object derived by referring to the relationship between the reference measuring force _F0 and the lower limit detection value _Dt stored in the storage unit 208. The output unit 210 may output information on the relationship between the reference measuring force _F0 and the lower limit detection value _Dt stored in the storage unit 208. An example of the information on the relationship between the reference measuring force _F0 and the lower limit detection value _Dt is the graph shown in FIG.

The output unit 210 can be an electrical circuit that outputs an electrical signal that represents the measuring force F of the object to be measured. For example, a video signal that represents the measuring force F of the object to be measured may be transmitted to the display device 24 via the output unit 210. The display device 24 can display the measuring force F of the object to be measured based on the transmitted video signal. The output unit 210 corresponds to an example of a measuring force information output unit.

The signal processing unit 200 shown in FIG. 6 can be implemented as a computer equipped with a processor, memory, and an input/output interface.

The roughness measuring instrument 10 shown in Fig. 1 includes a storage unit that stores the relationship between the reference measuring force _F0 and the lower limit detection value _Dt . The roughness measuring instrument 10 may include a signal processing unit 200. The signal processing unit 200 may be provided in a control device (not shown). The relationship between the measuring force and the lower limit detection value may be derived and stored during manufacturing inspection of the displacement detector 18.

[How to adjust the measuring force after replacing the stylus]
Using the above-mentioned relationship between the reference measuring force _F0 and the lower limit detection value _Dt , it is possible to obtain a target measuring force for the stylus 44 after the stylus 44 has been replaced. A method for adjusting the measuring force after the stylus has been replaced will be described below.

Figure 7 is a flow chart showing the steps of the measuring force adjustment method when replacing the stylus. The measuring force measurement method shown in Figure 7 can be realized by executing a measuring force measurement program using a control device.

In the stylus changing process S10, the stylus 44 is replaced. After the stylus changing process S10, the process proceeds to the lower limit detection value measuring process S12.

In the lower limit detection value measuring step S12, the lower limit detection value _Dt is measured. That is, the stylus 44 is moved to the lower limit position, and the detection value of the differential transformer type sensor 46 is obtained. After the lower limit detection value measuring step S12, the process proceeds to a measuring force calculation step S14.

In the measuring force calculation step S14, the measuring force F of the replaced stylus 44 is calculated. First, the lower limit detection value _Dt measured in the lower limit detection value measurement step S12 is converted to a reference measuring force _F0 using the relationship between the reference measuring force _F0 and the lower limit detection value _Dt shown in Fig. 5. The measuring force F of the measurement target of the replaced stylus 44 is calculated using the reference measuring force _F0 corresponding to the lower limit detection value _Dt .

When the total length of the replaced stylus 44 is L, the measurement force F of the measurement object of the replaced stylus 44 is expressed by the following formula 1.

F=(L ₀ /L)×F ₀ ...Formula 1
After the measuring force calculation step S14, the process proceeds to a determination step S16. After the measuring force calculation step S14, a display step of displaying the measuring force using the display device 24 may be executed. In the determination step S16, It is determined whether the measuring force F of the measurement object calculated in step S14 matches the target value of the measuring force of the replaced stylus 44.

In the judgment step S16, if the measuring force F of the measurement object calculated in the measuring force calculation step S14 does not match the target value of the measuring force of the replaced stylus 44, the result is No. Note that the term "match" here may include cases where there is an error within a specified range.

In other words, in the judgment step S16, if the measuring force F of the measurement object calculated in the measuring force calculation step S14 is outside the target range of the measuring force of the replaced stylus 44, a No judgment may be made. If the judgment is No, the process proceeds to the measuring force adjustment step S18.

In the measuring force adjustment step S18, the measuring force F of the object to be measured is adjusted using the measuring force adjustment mechanism 56 shown in Fig. 2 so as to become the lower limit detection value _Dt corresponding to the target value of the measuring force. After the measuring force adjustment step S18, the process proceeds to the lower limit detection value measurement step S12, and each step from the lower limit detection value measurement step S12 to the measuring force adjustment step S18 is repeatedly executed until the judgment step S16 is judged as Yes.

On the other hand, in the judgment step S16, if the measuring force F of the measurement object calculated in the measuring force calculation step S14 matches the target value of the measuring force of the replaced stylus 44, the judgment is Yes. If the judgment is Yes, the measuring force measurement method is terminated.

[Action and Effect]
According to the roughness measuring instrument 10 and the measuring force measuring method configured as above, the following advantageous effects can be obtained.

[1]
The device includes a detector arm 60 connected to the base end of the detection arm 42, and a stopper 62 that regulates the position of the detector arm 60 at the lower end position of the stylus 44. A detection value of the differential transformer sensor 46 corresponding to the deflection of the detector arm 60 is obtained. The measuring force F of the measurement object is derived by referring to a relationship between a reference measuring force _F0 and a lower limit detection value _Dt that is stored in advance. This makes it possible to measure the measuring force applied to the measuring point 20 using the differential transformer sensor 46 that detects the amount of displacement of the measuring point 20.

[2]
The measuring force F of the measured object is displayed using the display device 24. This allows an operator or the like to grasp the measuring force for each stylus 44.

[3]
A measuring force adjustment mechanism 56 is provided. The measuring force F of the measurement object is adjusted while measuring the lower limit detection value _Dt . This makes it possible to adjust the measuring force F of the measurement object to a target measuring force.

[Modifications of the detector arm]
2 can be made of the same material as the detection arm 42. That is, the detector arm 60 can be configured by extending the base end 42B of the detection arm 42. When the base end 42B of the detection arm 42 is extended, the base end side of the connection part with the differential transformer type sensor 46 functions as the detector arm 60.

The detector arm 60 may be made of a material different from that of the detection arm 42. The detector arm 60 may be made of a material that is more flexible than the detection arm 42. A connecting member may be used to connect the detection arm 42 and the detector arm 60.

The detector arm 60 may be made of a material that is partially flexible. For example, a flexible material may be used on the side where it is connected to the detection arm 42.

The detector arm 60 may have the same shape as the detection arm 42. A similar shape may include a case where the shape is different in the strict sense, but can be considered to be substantially the same shape. A shape different from the detection arm 42 may be used. Examples of the shape of the detector arm 60 include a cylinder and a square prism.

[Modification of the stopper]
Fig. 8 is a schematic diagram of a displacement detector according to a modified example of the stopper. The displacement detector 18A shown in Fig. 8 includes a detector arm 60A instead of the detector arm 60 shown in Fig. 2. Also, the stopper 62 is replaced by a stopper 62A.

A magnetic material is applied to the detector arm 60A shown in FIG. 8. An electromagnet using a coil is applied to the stopper 62A. That is, in the displacement detector 18A shown in FIG. 8, the detector arm 60A is fixed to the position of the stopper 62A using magnetic force. In other words, the stopper 62A regulates the position of the detector arm 60A.

The displacement detector 18A shown in FIG. 8 moves the stylus 44 to its upper limit position and obtains the detection value of the differential transformer sensor 46.

A stopper moving unit may be provided to move the stopper 62A, and the position of the detector arm 60 may be restricted at any position between the upper limit position and the lower limit position of the stylus 44, and a detection signal from the differential transformer sensor 46 may be obtained when the detector arm 60 is deflected.

[Modification of the sensor]
Fig. 9 is a schematic diagram of a displacement detector according to a modified example of the sensor. Fig. 9 shows an example of application to a contour measuring machine. The displacement detector 18B shown in Fig. 9 includes a scale type sensor 46B instead of the differential transformer type sensor 46 shown in Fig. 2.

In addition, the displacement detector 18B has a detector arm 60B instead of the detector arm 60 shown in FIG. 2, and has a stopper 62B instead of the stopper 62.

The scale-type sensor 46B is attached to a position closer to the tip of the detection arm 42 than the arm rotation fulcrum 40. The detector arm 60B is attached to the detection arm 42 via an attachment member 63. The attachment member 63 is connected to the base end of the detector arm 60B.

The attachment position of the detector arm 60B on the detection arm 42 is a position closer to the tip of the detection arm 42 than the arm rotation fulcrum 40, and is a position closer to the base end of the detection arm 42 than the position of the scale-type sensor 46B.

The mounting member 63 preferably has the same rigidity as the detection arm 42. Similar rigidity indicates the range in which the same action and effect can be obtained. For example, the same material as the detection arm 42 may be used. The detection arm 42 and the detector arm 60B may be arranged in parallel. Parallel may include substantially parallel, which can be considered as parallel, among non-parallel.

The stopper 62B is positioned so that it comes into contact with the tip of the detector arm 60B. The stopper 62B is attached to the fixing member 47 that fixes the scale-type sensor 46B.

The displacement detector 18B has a measuring force adjustment mechanism 56B instead of the measuring force adjustment mechanism 56 shown in FIG. 2. The measuring force adjustment mechanism 56B has a weight 57A, a screw 57B, and a frame 57C. The weight 57A is supported by the screw 57B so as to be freely movable along the detection arm 42. The screw 57B is attached to the detection arm 42 by the frame 57C.

The measuring force adjustment mechanism 56B can adjust the position of the weight 57A by operating the screw 57B. The measuring force adjustment mechanism 56B can adjust the measuring force by changing the overall center of gravity position of the detection arm 42 and the stylus 44 according to the position of the weight 57A. The measuring force adjustment mechanism 56B corresponds to an example of a measuring force applying section and an example of a measuring force adjusting section.

The above-described embodiment of the present invention may have its constituent elements modified, added, or deleted as appropriate without departing from the spirit of the present invention. The present invention is not limited to the above-described embodiment, and many modifications may be made by a person having ordinary knowledge in the relevant field within the technical concept of the present invention.

10...Roughness measuring instrument, 18...Displacement detector, 18A...Displacement detector, 18B...Displacement detector, 20...Probe, 24...Display device, 40...Arm rotation fulcrum, 42...Detection arm, 42A...Tip, 42B...Base, 44...Stylus, 46...Differential transformer type sensor, 46B...Scale type sensor, 50...Sensor, 54...Pressing member, 56...Measuring force adjustment mechanism, 60...Detector arm, 60A...Detector arm, 60B...Detector arm, 62...Stopper, 62A...Stopper, 62B...Stopper, 200...Signal processing unit, 206...Calculation unit, 208...Storage unit

Claims (5)

1. A shape measuring machine for measuring a shape of a workpiece by moving a measuring element attached to a tip end side of an arm rotatably supported on a rotation fulcrum relative to the workpiece, comprising:
a sensor attached to the arm for obtaining a detection value corresponding to a displacement amount of a tip of the measuring element;
a measuring force applying unit attached to the arm and biasing the arm to apply a measuring force to the tip of the probe;
a restricting portion that restricts a base end portion of the arm on the opposite side to the arm tip portion;
Equipped with
The sensor obtains the detection value corresponding to the measuring force in a state in which the position of the base end of the arm is regulated by the regulating portion by biasing the arm. The shape measuring machine according to claim 1, wherein the sensor obtains the detection value corresponding to the measuring force when the base end of the arm is bent. The shape measuring instrument according to claim 1 or 2, further comprising a measuring force adjustment mechanism attached to the other end of the measuring force applying section opposite to the end attached to the arm, for adjusting the measuring force applied to the tip of the measuring probe. The shape measuring instrument according to claim 3, wherein the measuring force adjustment mechanism adjusts the measuring force to a target measuring force of the tip of the probe based on the relationship between the detection value and the measuring force. 1. A method for adjusting a measuring force applied to a tip end of a measuring probe applied to a shape measuring machine comprising: an arm rotatably supported on a rotation fulcrum, the arm having an arm tip and an arm base end opposite the arm tip, the measuring probe attached to the arm tip side being moved relative to a workpiece to measure the shape of the workpiece, the method comprising:
Replace the probe,
The arm is biased to regulate the position of the base end of the arm and obtain a detection value.
calculating the measuring force based on the relationship between the detection value and the measuring force and the obtained detection value;
A measuring force adjusting method for adjusting the measuring force applied to the tip of the probe to a target measuring force of the tip of the probe.

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