JPH11101603A - Contact sensor and fitting structure thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact sensor that can detect an object to be measured sufficiently through minute vibration of a vibrating plate with high accuracy and making it easy to fit a contact to the vibrating plate, and provide a contact sensor fitting structure ensuring fixing of the vibrating plate so as to make detection of the measured object further accurate. SOLUTION: A piezoelectric element expanded/contracted by applying voltage thereto is stuck to the center side of one face of a metal plate 21 to constitute a vibrating plate, and a root side end part of a contact 29 is fitted to the other face edge part side of the metal plate 21 in the vibrating plate to constitute a contact sensor 20. The edge part side of the metal plate 21 in the vibrating plate in this contact sensor 20 is fixed to a fitting member 30 by a plurality of screws 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a contact sensor used for a three-dimensional scanner for detecting the presence or absence of an object to be measured and a mounting structure thereof.

[0002]

2. Description of the Related Art Hitherto, a three-dimensional scanner or the like has been developed which traces the surface of an object to be measured with the tip of a contact and detects the presence / absence and outer shape of the object. . As such a contact sensor, there is one disclosed in Japanese Patent Application Laid-Open No. 8-210805.

In this contact sensor, as shown in FIG. 7, a mounting base 2 having an L-shaped cross section is provided inside a box-shaped case 1, and a rubber fixing member 3 is mounted on the mounting base 2. , The contact sensor 4 is fixed. The contact sensor 4 has a piezoelectric element 6 attached to a lower surface of a diaphragm 5 and a drive electrode 7 and a detection electrode 8 provided on the lower surface.

[0006] Lead wires 9 and 10 extend from the drive electrode 7 and the detection electrode 8 to the outside of one side of the case 1. The diaphragm 5 also serves as an electrode of the piezoelectric element 6, and a lead wire 11 extends from the diaphragm 5 toward the outside of one side of the case 1.

[0005] From the center of the upper surface of the diaphragm 5, a linear contact 1 extends toward the outside of the other side of the case 1.
2 is extended. Therefore, when the piezoelectric element 6 is vibrated by applying an AC signal to the drive electrode 7, an AC signal having a voltage proportional to the magnitude of the vibration is generated at the detection electrode 8.
In this state, the presence or absence of the object to be measured can be detected by bringing the tip of the contact 12 into contact with the object to be measured and suppressing the vibration of the diaphragm 5.

[0006]

The portions of the vibration plate 5 and the piezoelectric element 6 in the contact sensor 4 as described above have the same configuration as a piezoelectric buzzer used for general household goods. Therefore, in the case of such a contact sensor 4,
If the applied voltage is large, there is a problem that the diaphragm 5 emits a buzzer sound and the operator feels discomfort.

Further, when vibrating plate 5 and piezoelectric element 6 vibrate, contact 12 is oscillated while reversing the bending up and down as shown by broken lines a and b in FIG. . However, since the root-side end of the contact 12 is fixed to the center of the diaphragm 5, the amplitude of the swing of the contact 12 at the tip side is larger than the amplitude of the diaphragm 5 and the piezoelectric element 6. Not so big.

As a result, when the applied voltage is large, the unpleasant sound is generated as described above, and when the applied voltage is small, the contact 12 does not vibrate much, and the object to be measured contacting the tip cannot be detected. Has occurred. Contact 1
When the body 2 vibrates, its body contacts the edge of the diaphragm 5,
This contact prevents the contact element 12 from being given an appropriate vibration. As a result, there is a problem that the function as a sensor is reduced. In order to avoid this, a troublesome work such as changing the shape by bending the root side of the contact into an L-shape is required.

In the above example, since the fixing member 3 for fixing the contact sensor 4 to the mounting base 2 is made of rubber, there is a problem that strength and durability are inferior. Further, since it is difficult to reliably fix the diaphragm 5 with the rubber fixing member 3, the diaphragm 5 becomes unstable during vibration. As a result, similarly to the above, there arises a problem that it is difficult to apply an appropriate vibration to the contact 12.

The present invention has been made in view of such circumstances, and the object to be measured can be sufficiently detected by the vibration of the diaphragm to such an extent that no buzzer sound is generated, and the accuracy of the object is good. The present invention provides a contact sensor that facilitates attachment of a transducer to a diaphragm, and an attachment structure of the contact sensor that enables more accurate detection of an object to be measured by securely fixing the diaphragm. Aim.

[0011]

In order to achieve the above-mentioned object, a contact sensor according to the present invention comprises a piezoelectric element which expands and contracts when a voltage is applied to one surface of a metal plate, and vibrates. A plate is formed, and a root-side end of the contact is attached to the other side of the metal plate in the vibration plate.

That is, in this contact sensor, the root end of the contact is attached to the edge of the metal plate of the diaphragm so that the vibration width of the tip of the contact increases even when the amplitude of the diaphragm is small. In addition, the body of the contact is prevented from contacting the edge of the diaphragm.

Therefore, even when the applied voltage is reduced so that no buzzer sound is generated, the object to be measured can be reliably detected. Further, since the body of the contact does not contact the edge of the diaphragm as in the conventional example, the detection accuracy is improved.

Further, in the mounting structure of the contact sensor, the edge of the metal plate in the vibration plate is fixed to the mounting member with a plurality of screws. Therefore, as compared with the conventional example, the attachment to the attachment member is strengthened, the diaphragm vibrates more stably, and the detection accuracy is improved.

Further, the position of the root-side end of the contact on the metal plate is set at approximately the center of two adjacent screws among the plurality of screws, so that The contact can be mounted at a position farthest from the fixed portion where vibration hardly occurs. As a result, the contact is attached to a portion of the edge of the metal plate where vibration is most likely to be transmitted, and effective detection is possible.

Preferably, the diaphragm is attached to the attachment member with three or two screws, and the fixing position is at a corner of a substantially equilateral triangle inscribed in the disk-shaped diaphragm. It is preferable to use a portion corresponding to three or two places. Hereinafter, a contact sensor and a mounting structure of the contact sensor according to the present invention will be described in detail with reference to the drawings.

[0017]

1 and 2 show an example of a contact sensor according to the present invention. This contact sensor 2
At 0, a piezoelectric element 24 composed of a piezoelectric ceramics 22 and an electrode 23 is adhered to the center of one surface of a disc-shaped metal plate 21 made of brass. Then, a portion from the center to the lower end of the electrode 23 is cut in an inverted U-shape, and the piezoelectric ceramic 22 on the lower side is exposed at the portion.

The inverted U-shaped portion 22a of the electrode 23
Outside portion constitutes a main electrode 23a, and the inverted U-shaped portion 22
The inner part of a constitutes a return electrode 23b. Also,
The metal plate 21 is a ground electrode. The main electrode 23a, the return ring electrode 23b, and the ground electrode are respectively connected to lead wires 2 connected to a printed circuit board (not shown).
5, 26 and 27 are connected.

When a voltage is applied between the main electrode 23a and the metal plate 21, the piezoelectric element 24 is distorted by the piezoelectric effect.
4 expands and contracts. The metal plate 21 vibrates due to the expansion and contraction of the piezoelectric element 24, and the vibration plate 28 is formed by the piezoelectric element 24 and the metal plate 21.

A root-side end 29a of a contact 29 made of stainless steel is fixed to the other end of the diaphragm 28 by soldering.
The contact 29 is moved by the vibration of the diaphragm 28 as shown in FIG.
As shown in FIG. In FIGS. 3 and 8, the movement of the contacts 29 and 12 is overdrawn for easy understanding, but the amplitude of the tip of the actual operation is about 1 μm.

The contact sensor 20 configured as above is
It is attached to the attachment member 30 as shown in FIGS. The attachment member 30 is attached to the carriage 32 of the three-dimensional scanner 31 shown in FIG. 6, and is formed of a square plate. This mounting member 30
, Three screws 33 penetrate in a regular triangle, and the screw portion has screw holes at both ends.
One of the screw holes of the long nuts 34 is screwed and fixed (only two screws 33 and long nuts 34 are visible in the figure).

A screw 35 is screwed into the other side of the screw hole of the long nut 34, and the long nut 34 and the screw 3
5, the edge side portion of the diaphragm 28 is sandwiched.
In this case, the contact sensor 20 is positioned such that the root end 29a of the contact 29 is located at the center of the two lower screws 35. Further, two screw insertion holes 36 and 37 for mounting to the carriage 32 are formed on both left and right sides of the mounting member 30.

As shown in FIG. 6, the three-dimensional scanner 31 to which the mounting member 30 is mounted has a carriage 32.
Are movable left and right (X direction) along two rails 38 and 39 extending parallel to the horizontal direction. And
A table 41 for fixing the device under test 40 is movable back and forth (Y direction) along a rail (hidden and invisible in the figure).

The carriage 32 is provided with two rails 42 and 43 extending in parallel in the vertical direction, and the fixing member 44 is movable along the rails 42 and 43 in the vertical direction (Z direction). Installed. The mounting member 30 to which the contact sensor 20 is mounted is fixed to the fixing member 44 via two screws 45 inserted through the screw holes 36 and 37.

Therefore, the contact 29 of the contact sensor 20
Is relatively movable in the X, Y, and Z directions with respect to the measured object 40. When the tip of the contact 29 comes into contact with the measured object 40 in a vibrated state, the vibration is stopped.

In this configuration, when the object to be measured 40 is detected by the three-dimensional scanner 31, first, the contact sensor 20 is attached to the attachment member 30, and the attachment member 30 is attached to the fixing member 44 of the carriage 32. Fixed to. Next, the device under test 40 is fixed on the table 41.

Then, via the lead wires 25 and 27, 3
By applying a voltage to the piezoelectric element 24 based on a signal sent from the control unit of the dimensional scanner 31, the piezoelectric element 24 expands and contracts, and the diaphragm 28 vibrates. as a result,
The contact 29 vibrates little by little. In this state, by moving the carriage 32, the table 41, and the fixing member 44 in predetermined directions, respectively,
Is brought into contact with a predetermined portion on the surface of the device under test 40.

As a result, the vibration of the contact 29 stops, and at the same time, the vibration of the diaphragm 28 also stops. The return electrode 23b senses a voltage generated when the piezoelectric element 24 vibrates and feeds it back as data. When the voltage changes, the contact 29 comes into contact with the DUT 40. Can be understood.

The contact point between the contact 29 and the object 40 is determined as a point on the coordinates. Further, the same operation is performed by slightly changing the relative position between the contact 29 and the DUT 40 to obtain the next contact point. The shape data of the DUT 40 can be obtained by sequentially performing this process and determining the contact point over the entire surface of the DUT 40 as a point on the coordinates.

In this case, since the vibration is transmitted from the vibration plate 28 to the contact 29 sensitively, even if the voltage applied to the piezoelectric element 24 is reduced, the object 40 can be reliably detected. In addition, the accuracy of the detection is improved. Further, since the diaphragm 28 of the contact sensor 20 used in this example has the same configuration as the diaphragm of a generally used piezoelectric buzzer, this diaphragm can also be used. As a result, economical effects can be achieved at low cost.

In the mounting structure according to the above example, the mounting of the contact sensor 20 to the mounting member 30 is performed by three screws 33, a long nut 34, and a screw 3 arranged at equal intervals.
5, but the present invention is not limited to this, and each may be two or more than three. According to the experiment, in the case of two, good results could be obtained when the screw 35 and the like at the position corresponding to the top of the triangle in the above example were removed.

[0032]

As described above, in the contact sensor according to the present invention, since the root end of the contact is attached to the edge of the metal plate, the applied voltage is reduced so as not to generate a buzzer sound. However, the object to be measured can be reliably detected. Further, since the body of the contact does not contact the edge of the diaphragm, the detection accuracy is good.

Further, since the contact sensor is fixed to the mounting member by a plurality of screws, the mounting structure is strengthened and the diaphragm generates stable vibration. Thereby, the accuracy of the detection is further improved. Furthermore, since the contact position of the contact to the metal plate is set to be approximately the center of two adjacent screws,
The vibration of the diaphragm is efficiently transmitted to the contact, and the object to be measured can be effectively detected.

[Brief description of the drawings]

FIG. 1 is a rear view showing a contact sensor according to an example of the present invention.

FIG. 2 is a front view of the contact sensor.

FIG. 3 is an explanatory diagram showing a state in which a contact vibrates.

FIG. 4 is a front view showing a state where the contact sensor is mounted on a mounting member.

FIG. 5 is a side view showing a state where the contact sensor is attached to an attachment member.

FIG. 6 is a front view showing a main part of a three-dimensional scanner to which a contact sensor is attached.

FIG. 7 is a sectional view showing a contact sensor according to a conventional example.

FIG. 8 is an explanatory diagram showing a state in which a contact sensor according to a conventional example vibrates.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 ... Contact sensor 21 ... Metal plate 24 ... Piezoelectric element 28 ... Vibration plate 29 ... Contact 29a ... Root end 30 ... Mounting members 33, 35 ... Screw 34 ... Long nut 40 ... DUT

Claims (3)

[Claims] 1. A contact sensor that is attached to an attachment member that moves in the X, Y, and Z directions relative to an object to be measured, and that detects the contact by bringing the tip of a contact into contact with the object to be measured. A piezoelectric element that expands and contracts when a voltage is applied is attached to the center of one surface of the metal plate to form a vibrating plate. Attach the end and project its tip outward, apply a voltage to the piezoelectric element to expand and contract the piezoelectric element, vibrate the diaphragm, move the mounting member in that state, and move the tip of the contactor. A contact sensor characterized in that the object is detected by bringing the object into contact with the object to suppress the vibration. 2. The mounting structure of a contact sensor according to claim 1, wherein an edge of the metal plate in the contact sensor is fixed to the mounting member by a plurality of screws kept at a predetermined interval. And a contact sensor mounting structure in which a root-side end of the contact is attached to a metal plate at a substantially central portion of two adjacent screws among the plurality of screws. 3. A diaphragm is formed in a disk shape, and the diaphragm is attached to a mounting member by screwing a portion corresponding to three or two corners of a substantially equilateral triangle inscribed in the diaphragm. The mounting structure of the contact sensor according to claim 2, wherein the mounting structure is performed by fixing.