JP3587915B2 - Touch signal probe - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a touch signal probe used when measuring the shape or the like of an object to be measured by a three-dimensional measuring device or the like, and more particularly, to an improvement in a structure of a support portion of a vibrator.
[0002]
[Background Art]
Height gauges (one-dimensional measuring machines), three-dimensional measuring machines, contour measuring machines, etc. are known as measuring machines for measuring the shape, dimensions, etc. of an object to be measured. In addition, a touch signal probe for detecting contact with an object to be measured is used for the measuring device.
[0003]
A conventional structure of this touch signal probe is disclosed in Japanese Patent Application Laid-Open No. 6-221806. As shown in FIG. 6, the touch signal probe 110 includes a hollow cylindrical stylus holder 112, and a substantially columnar vibrator 114 is provided at a lower end inside the stylus holder 112 at a substantially central portion in the axial direction. It is supported by a support pin 118 that penetrates the support point.
[0004]
At the lower end of the vibrator 114, a contact ball 114A that is in contact with the object to be measured at the time of measurement is attached, and at the upper end thereof, a balancer 114B having the same weight as the contact ball 114A is attached. A piezoelectric element 116 is attached to a substantially central portion of the vibrator 114 with an adhesive or the like.
The surface electrode of the piezoelectric element 116 is divided into a vibrating element that vibrates the vibrator 114 and a detection element that extracts the vibration of the vibrator 114 as an electric signal. When electricity of an appropriate frequency is applied to the vibrating element, the vibrator 114 resonates and vibrates with the support pin 118 as a node of vibration and the contact ball 114A as an antinode of vibration.
[0005]
It is necessary to support the vibrator 114 on the stylus holder 112 so as not to restrain the resonance vibration. Ideally, the node of the vibration should be firmly supported in the arealess area. That is, if the vibration is restrained, energy loss occurs in the restrained portion, leading to deterioration in sensitivity. Therefore, the vibrator 114 must be supported by the stylus holder 112 as softly as possible.
However, the measurement principle is established on the premise that the tip contact ball 114A of the vibrator 114 has a certain geometric relationship with the stylus holder 112 directly connected to the main body of the coordinate measuring machine or the like. And the vibrator 114 must be firmly supported to keep the positional relationship constant.
Therefore, the support of the stylus holder 112 on the vibrator 114 must be soft so as not to restrict the resonance state, and must satisfy the conflicting demands of maintaining the positional relationship between them both constant without any disturbance. No.
[0006]
[Problems to be solved by the invention]
In the conventional example disclosed in JP-A-6-221806, a support pin 118 having a small diameter is inserted and attached to the center of the vibrator 114, and both ends of the pin 118 are fixed to the stylus holder 112. Although there is an advantage that the vibration of the vibrator 114 is hardly restrained, when an excessive force acts on the tip of the vibrator 114, the vibrator 114 rotates around the axis of the support pin 118, and the vibrator 114 and the stylus holder 112 There is a problem that the positional relationship is shifted.
[0007]
In order to solve this problem, as shown in FIG. 7, it is conceivable that the vibrator 114 is supported by a prism 120 having a larger sectional area than the support pin 118 instead of the support pin 118.
However, supporting both sides of the central portion of the vibrator 114 with the prism 120 restrains the vibration of the vibrator 114 and has a disadvantage that sensitivity is reduced.
[0008]
In addition, the touch signal probe shown in FIGS. 6 and 7 has a structure in which the support pins 118 and the prisms 120 are extended on both sides of the central portion of the vibrator 114 and both ends thereof are fixed to the stylus holder 112, so that the rigidity is increased. Although there is an advantage that the stylus holder 112 is strong against disturbance vibration, when there is a temperature change, it is often difficult to make the entire temperature distribution of the stylus holder 112 uniform.
Therefore, in the touch signal probe, when the shape of the stylus holder 112 is distorted due to a temperature change, thermal stress is applied to the vibrator 114 via the support portion, and the vibration mode of the vibrator 114 changes. There is a problem that.
[0009]
The present invention has been made in view of such circumstances, and its purpose is to reliably support a vibrator on a stylus holder, and to achieve high sensitivity and high accuracy without disturbing vibration even when there is a temperature change. It is to provide a touch signal probe that can be achieved.
[0010]
[Means for Solving the Problems]
Therefore, an object of the present invention is to achieve the above object by connecting a vibrator to a stylus holder in a cantilever manner via an arm extending to one side in a direction intersecting the axial direction thereof.
Specifically, the touch signal probe of the present invention includes a stylus holder, a substantially columnar vibrator that is supported by the stylus holder and has a contact portion at its tip that comes into contact with the object to be measured, and a shaft of the vibrator. A vibrating element that is disposed near a node of the direction natural vibration and vibrates the vibrator at a frequency substantially equal to the natural frequency, and disposed near a node of the axial natural vibration of the vibrator; In a touch signal probe including a detection element for detecting a change in a vibration state due to the contact when the contact portion comes into contact with an object to be measured, the vibrator includes a stylus body and an axial natural vibration of the stylus body. and a mounting portion for together provided knurl mounting the vibrating element and the detecting element, the mounting portion, the vibration in the section of the axial natural frequency of the oscillator It has an arm portion which extends to one side in the direction orthogonal to the axial direction of the child, characterized by coupling the transducer to the stylus holder at the arms.
[0011]
In the present invention having this configuration, since the vibrator and the arm, which is the support portion, are integrated and connected, the positional relationship between the stylus holder and the vibrator is maintained constant, and the support of the vibrator to the stylus holder is ensured. It can be something. In addition, since the vibrator is supported by the stylus holder in a cantilever state, even if the Stice holder is deformed due to thermal deformation, the vibrator is rarely subjected to thermal stress via the supporting portion, and the vibrator is supported by the stylus holder. The vibration mode does not change.
[0012]
In the present invention, the vibrator, the attachment portion and the stylus holder may be integrally formed structure.
With this structure, the structure of the touch signal probe can be simplified and the assembling operation can be easily performed.
[0013]
In the present invention, the stylus holder is provided with a holder-side mounting plate portion, the vibrator have a structure having a attachable stylus side mounting plate portion provided in the front Kiude portion the holder-side mounting plate portion Good.
In this structure, the vibrator is detachably attached to the stylus holder, so that the vibrator can be easily replaced.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, preferred embodiments of the touch signal probe according to the present invention will be described in detail with reference to the accompanying drawings. Here, in each embodiment, the same or similar components are denoted by the same reference numerals, and description thereof will be omitted or simplified.
FIG. 1 is a perspective view showing a main part of the touch signal probe according to the first embodiment, and FIG. 2 is an exploded perspective view of the touch signal probe of FIG.
As shown in FIG. 1, a touch signal probe 1 according to the first embodiment includes a stylus holder 2 having an L-shaped side surface, a substantially columnar vibrator 3 supported by one piece 2A of the stylus holder 2, A piezoelectric element 4 attached to the vibrator 3; a stylus holder 2 attached to a moving shaft such as a three-dimensional measuring machine (not shown); the moving shaft detects contact with an object to be measured while moving; The shape and the like are measured by reading the coordinates at the time of contact.
[0015]
The vibrator 3 has a configuration including a substantially cylindrical stylus main body 5, and a mounting portion 6 provided at a central portion of the stylus main body 5, which is a node of the natural vibration in the axial direction, for mounting the piezoelectric element 4. is there.
The stylus main body 5 has a structure having a contact ball 5A, which is a contact portion that comes into contact with the object to be measured at one end, and a balancer 5B having the same weight as the contact ball 5A at the other end. Since the contact ball 5A is attached to one end of the vibrator 3, the balancer 5B balances weight so that a node of vibration at the time of resonance does not deviate from the center of the vibrator 3, and balances the touch signal probe 1. Is moved in a direction intersecting with the vibration direction of the vibrator 3 so as not to receive a moment around the support point when receiving acceleration. Therefore, the shape of the balancer 5B may be the same as or different from that of the contact ball 5A.
[0016]
As shown in FIG. 2, the attachment portion 6 is formed in a box shape having attachment pieces 6 </ b> A on both front and back surfaces and having an insertion hole 6 </ b> B through which the stylus body 5 is inserted. After the stylus body 5 is inserted into the insertion hole 6B, it is fixed to the mounting portion 6 by brazing or the like. In order to facilitate the work of inserting the stylus body 5 into the insertion hole 6B, an insertion hole 2C is formed in the other piece 2B of the stylus holder 2, and the stylus 5A is inserted into the stylus after being inserted into the insertion hole 6B. The main body 5 is fixed by brazing or the like.
[0017]
An arm 7 extends to one side of the mounting portion 6 in a direction orthogonal to the axial direction of the stylus body 5, and the vibrator 3 is coupled to the stylus holder 2 via the arm 7. The arm 7 is formed integrally with the attachment 6 and the stylus holder 2. The cross-sectional shape of the arm 7 is not limited to the rectangular shape shown in FIGS. 1 and 2, but may be various shapes such as a circular shape and an elliptical shape.
[0018]
Two piezoelectric elements 4 having the same shape are attached to the attachment piece 6A of the attachment portion 6 by an adhesive or the like.
When the piezoelectric element 4 vibrates the vibrator 3 at a frequency substantially equal to the natural frequency of the vibrator 3, the vibrating element 4A and the contact ball 5A of the vibrator 3 contact the object to be measured. It is divided into a detection element 4B for detecting a change in the vibration state due to the contact, and these elements 4A and 4B are operated by a circuit shown in Japanese Patent Application Laid-Open No. 6-221806. That is, two signal lines (not shown) are wired to the excitation element 4A and the detection element 4B, and one of these signal lines is connected to a drive circuit that vibrates the vibrator 3 as an actuator, The other signal line is connected to a detection circuit that detects vibration of the vibrator 3. Each signal line wired from the two piezoelectric elements 4 is connected in parallel, and a common ground line is connected to the back surfaces of these piezoelectric elements 4 with the same electrode.
[0019]
Next, the operation of the touch signal probe 1 according to the first embodiment will be described.
When measuring the shape and the like of the object to be measured, electricity of an appropriate frequency is applied to the vibrating element 4A. Then, the vibration element 4A starts oscillating at a predetermined frequency, and the piezoelectric element 4 is brought into a resonance state. At the time of resonance, the arm 7 which is the center of the vibrator 3 serves as a node of vibration, and the end of the vibrator 3, that is, the contact ball 5A and the balancer 5B serve as antinodes of vibration.
When the contact ball 5A comes into contact with the measured object in the resonance state, energy loss occurs in the vibrator 3 in response to the restraint of the vibration due to the contact, so that the sensor signal of the vibrator 3 sent from the detection element 4B changes. . Then, a change in the sensor signal is detected by the circuit, and a touch signal is output to the measuring device main body. As a result, the coordinate values at that time are taken into the measuring instrument main body, and thereby the coordinate detection is performed.
[0020]
Therefore, according to the first embodiment, {circle around (1)} the substantially columnar vibrator 3 is supported on the stylus holder 2, and the vibrating element 4A and the detecting element 4B are located near the node of the vibrator 3 in the axial natural vibration. In the touch signal probe 1 in which is disposed, the arm 7 is extended to one side in a direction intersecting with the axial direction of the vibrator 3 at the node of the natural vibration of the vibrator 3 in the axial direction, and through the arm 7 Since the vibrator 3 is coupled to the stylus holder 2, the positional relationship between the stylus holder 2 and the vibrator 3 can be kept constant to ensure that the vibrator 3 is supported on the stylus holder 2, and furthermore, the vibration Since the stylus holder 2 supports the stylus holder 2 in a cantilever state, even if the stylus holder 2 is deformed due to thermal deformation, the vibrator 3 is less likely to be subjected to thermal stress and does not hinder the vibration. Achieve high sensitivity and high accuracy of the probe It can be.
[0021]
(2) Since the vibrator 3 is supported by the stylus holder 2 at the node at the time of resonance, a probe that is insensitive to disturbance vibration, that is, has high stability and does not cause erroneous detection. It is feasible.
In the first embodiment, (3) the vibrator 3 is provided on the stylus main body 5 and the node of the natural vibration in the axial direction of the stylus main body 5, and the piezoelectric element 4 (the vibrating element 4A and the detecting element 4). 4B), the mounting portion 6, the stylus holder 2 and the arm portion 7 are integrally formed, so that the structure of the touch signal probe 1 can be simplified and the assembling operation can be easily performed. Accordingly, since the assembling is easy, the touch signal probe 1 which is inexpensive and does not deteriorate in performance even for long-term use can be realized.
[0022]
Furthermore, (4) the mounting portion 6 has a structure having an insertion hole 6B through which one stylus main body 5 is inserted, so that the assembling work of the vibrator 3 can be easily performed.
(5) Since the angle between the stylus main body 5 and the arm 7 is made orthogonal, the manufacture of the touch signal probe 1 is also easy from this point.
[0023]
Next, a second embodiment of the present invention will be described with reference to FIGS.
The second embodiment is different from the first embodiment in the configuration of the stylus holder, the vibrator, and the arm, and the other configurations are the same as those in the first embodiment.
FIG. 3 is a sectional view showing a main part of the touch signal probe according to the second embodiment, and FIG. 4 is an exploded perspective view of the touch signal probe of FIG.
In these drawings, the touch signal probe 11 according to the second embodiment includes a stylus holder 12, a substantially columnar vibrator 13 supported by the stylus holder 12, and the piezoelectric device attached to the vibrator 13. The stylus holder 12 is attached to a moving shaft of a coordinate measuring machine (not shown).
[0024]
The stylus holder 12 is formed in a substantially cylindrical shape with a bottom and has a slit 12B of a predetermined length formed in the opening along the axial direction, and is integrally formed near the slit 12B of the main body 12A. And a holder-side mounting plate 12C.
The vibrator 13 includes the stylus main body 5 and a mounting portion 16 provided at a node of the stylus main body 5 for natural vibration in the axial direction and for mounting the piezoelectric element 4. 6 and the arm 16 extending to one side of the body 16A in a direction orthogonal to the axial direction of the stylus body 5 and attached to the holder-side mounting plate 12C with screws 20. And a stylus-side mounting plate 16B.
[0025]
Here, the arm 7, the main body 16A, and the stylus-side mounting plate 16B are integrally formed. The slit 12B of the stylus holder 12 has a width dimension sufficient for the arm 7 to be inserted.
The stylus body 5 is divided into a first divided body 5C having a contact ball 5A and a second divided body 5D having a ballast 5B at the center thereof, and these divided bodies 5C and 5D are inserted into the insertion hole 6B from the left and right sides. After being inserted, it is fixed to the mounting portion 16 by brazing or the like.
[0026]
In the second embodiment, the operation is the same as that of the first embodiment, and the following effects can be obtained in addition to the effects (1) and (2) of the first embodiment. it can.
That is, in the second embodiment, the stylus holder 12 includes the holder-side mounting plate portion 12C, and the vibrator 13 is provided on the stylus main body 5 and the node of the stylus main body 5 for the natural vibration in the axial direction. 4A and a mounting portion 16 for mounting the detecting element 4B. The mounting portion 16 is provided via an arm 7 extending to one side in a direction orthogonal to the axial direction of the stylus main body 5 and is provided on a holder side mounting plate. Since the stylus-side mounting plate portion 16B that can be mounted to the portion 12C is provided, the vibrator 13 is detachably mounted on the stylus holder 12, so that the vibrator 13 can be easily replaced.
[0027]
Further, since the arm 7, the main body 16 </ b> A and the stylus-side mounting plate 16 </ b> B forming the mounting part 16 are formed integrally, the structure of the vibrator 13 is simplified.
In the second embodiment, as shown in FIG. 5, the main body 16A, the arm portion 7, and the stylus-side mounting plate portion 16B are manufactured separately, and these are appropriately formed by brazing, bonding, or the like. It may be configured to be integrally connected.
[0028]
As described above, the present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to these embodiments, and various improvements and design changes may be made without departing from the gist of the present invention. Of course, it is possible.
[0029]
For example, in each of the embodiments described above, a case where the present invention is applied to a three-dimensional measuring machine is described. However, the present invention is not limited to this, and is applied to a height gauge (one-dimensional measuring machine), a two-dimensional measuring machine, a contour measuring machine, and the like. It is also possible.
In addition, the extending direction of the arm portion 7 only needs to intersect with the axial direction of the stylus main body 5 and does not necessarily need to be orthogonal.
Further, the structure in which the piezoelectric elements 4 are directly attached to the stylus body 5 may be employed without necessarily providing the attachment portions 6 and 16 in the vibrators 3 and 13.
[0030]
In each of the above embodiments, the piezoelectric element 4 constituting the vibrating element 4A and the detecting element 4B is disposed at the center of the vibrators 3 and 13. In the present invention, the piezoelectric element 4 is described in Japanese Patent Application Laid-Open No. 6-221806. May be arranged in the vicinity of a node of another axial natural vibration.
Further, the vibrating element 4A and the detecting element 4B do not necessarily need to be formed from one piezoelectric element 4. For example, these elements 4A and 4B are formed from separate piezoelectric elements, and these piezoelectric elements are different. The vibrators 3 and 13 may be arranged near nodes of the axial natural vibration.
[0031]
【The invention's effect】
As described above, according to the present invention, in a touch signal probe in which a substantially columnar vibrator is supported on a stylus holder, and a vibrating element and a detecting element are arranged near nodes of an axial natural vibration of the vibrator, The arm is extended to one side in the direction intersecting with the axis of the vibrator at the node of the vibrator's axial natural vibration, and the vibrator is connected to the stylus holder via this arm. Since the positional relationship with the vibrator is maintained constant, the vibrator can be reliably supported by the stylus holder, and furthermore, the vibrator is supported by the stylus holder in a cantilever state. Accordingly, even if the Steis holder is deformed, thermal stress is less likely to be applied to the vibrator, and high sensitivity and high accuracy of the probe can be achieved without disturbing the vibration.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main part of a touch signal probe according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view of the touch signal probe of FIG. 1;
FIG. 3 is a cross-sectional view illustrating a main part of a touch signal probe according to a second embodiment of the present invention.
FIG. 4 is an exploded perspective view of the touch signal probe of FIG. 3;
FIG. 5 is a perspective view showing details of a mounting portion of a touch signal probe according to a second embodiment.
FIG. 6 is a partially broken perspective view showing a main part of a conventional touch signal probe.
FIG. 7 is a partially cutaway perspective view showing a main part of a touch signal probe on which the present invention is based.
[Explanation of symbols]
1,11 touch signal probe 2,12 stylus holder 3,13 vibrator 4 piezoelectric element 4A vibrating element 4B detecting element 5 stylus body 6,16 mounting part 7 arm part 12C holder side mounting plate part 16B stylus side mounting plate part

Claims (3)

A stylus holder, a substantially columnar vibrator supported by the stylus holder and having a contact portion at its tip for contacting an object to be measured, the vibrator being disposed near a node of an axial natural vibration of the vibrator, and A vibrating element that vibrates the vibrator at a frequency substantially equal to a frequency, and a vibrating element that is disposed near a node of the axial natural vibration of the vibrator and the contact portion contacts the object to be measured. In a touch signal probe including a detection element for detecting a change in vibration state due to contact,
The vibrator includes a stylus main body, and a mounting portion provided at a node of the axial natural vibration of the stylus main body and mounting the vibrating element and the detection element,
The mounting portion has an arm portion which extends to one side in the direction orthogonal to the axial direction of the vibrator In the section of the axial natural frequency of the vibrator, wherein the vibrator at the arms A touch signal probe, which is coupled to a stylus holder. Touch signal probe in the touch signal probe according to claim 1, before Quito attaching portion and the stylus formal Da is characterized in that it is integrally formed. In the touch signal probe according to claim 1, wherein the stylus holder is provided with a holder-side mounting plate portion, the vibrator can be attached stylus side mounting plate portion to the holder-side mounting plate provided in the front Kiude portion A touch signal probe, comprising:

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