JP2547040Y2 - Contact probe device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact probe device for measuring the shape of a machined work by contact in a numerically controlled automatic machine tool. More specifically, the present invention relates to wirelessly transmitting a contact signal between a stylus and the work. The present invention relates to a structure of an antenna unit for transmitting.

[0002]

2. Description of the Related Art Conventionally, in an automatic machine tool, after processing a work with various tools, the three-dimensional shape of the processed work is measured. At this time, a contact probe device is mounted on the spindle.

This contact probe device is driven to be displaced in a three-dimensional direction together with the main shaft. Then, the shape of the work is measured from the position in each of the three-dimensional directions where the stylus and the work come into contact with each other.

In this case, it is necessary to transmit a contact signal between the stylus and the work to the control unit of the automatic machine tool. Conventionally, there are the following three transmission methods.

The first is a wired system in which the contact probe device and the control unit are directly connected by lead wires.

In this method, not only is the range of movement of the contact probe device limited by the length of the lead wire,
There is a risk of disconnection.

The second is an optical system, in which a contact signal is transmitted as an optical signal such as infrared light to a receiver located at a distant position (for example, see Japanese Patent Publication No. 3-69045).

In this method, there is no danger of an accident such as breakage of the lead wire, but it is necessary to arrange the contact probe device on the transmitting side and the receiving unit in a position where they can be seen from each other, and there are restrictions on the location.

The third is a wireless system for wirelessly transmitting a contact signal. In this system, since there is no directionality of transmission and reception unlike the optical system, neither the contact probe device nor the receiving unit is hardly restricted in location.

A conventional example of the wireless contact probe device is disclosed in US Pat. No. 4,118,871.
This device has a housing attachable to the spindle,
While providing a stylus at one end of this housing,
A transmission circuit and a battery are provided inside the housing,
The stylus also serves as a transmitting antenna element. And the stylus, which is the antenna element,
It emits a certain level of radio waves while not in contact with the workpiece. Then, when the stylus comes into contact with the work, the transmission level of the radio wave rapidly attenuates, and the control unit on the receiving side detects the contact between the stylus and the work from the attenuation of the radio wave.

[0011]

By the way, in a wireless contact probe device using a stylus as an antenna element as described above, the amount of transmission radio wave attenuation at the time of contact is small depending on the conductivity of the work, and the contact is detected. Can be difficult. Further, if the length of the stylus does not correspond to the wavelength of the radio wave used, the radiation efficiency is reduced and the transmission becomes uncertain.

Further, since the stylus as the antenna element is entirely exposed to the outside, cutting oil or cutting debris adheres to the stylus and short-circuits with other metal parts of the contact probe device, thereby generating noise. However, transmission and reception may be hindered.

The present invention has been made in view of the above-mentioned conventional problems. In a wireless contact probe device, a member different from a stylus is used as an antenna element and provided so as not to be exposed to the outside. It is another object of the present invention to reliably perform wireless transmission of a contact signal.

[0014]

In order to achieve the above object, the present invention provides a housing which can be attached to a main shaft of a machine tool, and a contact signal between a stylus attached to a tip of the housing and a work is provided. In the contact probe device for wireless transmission, a resin cylinder is provided on the outer periphery of the housing, and an antenna element having a spring property is fitted on the inner peripheral surface of the cylinder.

[0015]

In the above construction, the antenna element adheres to the inner peripheral surface of the cylindrical body by its own spring property, and is fixed in a state where it does not come into contact with other metal parts of the housing. In the mounted state, the antenna element is covered with a tubular body, and the attachment of cutting oil and cutting waste is prevented. The length of the antenna element may be set to a value corresponding to the wavelength of the used radio wave within the range of the circumference of the cylindrical body.

[0016]

FIG. 1 is a side view showing the inside of a contact probe device according to an embodiment of the present invention, with a part cut away, and FIG. 2 is an exploded perspective view of a cylindrical portion thereof.

The contact probe device of this embodiment includes a housing 1, a stylus 2, a transmission circuit 3, a battery 4,
A cylinder 5 and an antenna element 6 are provided.

The housing 1 is mounted on a main shaft of a machine tool. On the mounting side, there are a tapered portion 1a and a grip portion 1b inserted into the main shaft like a collet chuck, and a stylus 2 is mounted on the other end. Have been. The transmission circuit 3 generates a transmission signal indicating the contact between the stylus 2 and the work, and includes a circuit board 3 a and a housing 1.
And a battery 4 built in the tapered portion 1a of the housing 1 via a connector 3b.

The cylindrical body 5 is tightly fitted to the outer periphery of the central body of the housing 1 via an O-ring 7 and is fixed by screws 8, and is made of resin. 2, a circumferential groove 5a for the antenna element 6 is formed. The antenna element 6 is formed of a metal strip having a predetermined length having a spring property, and is mounted in the circumferential groove 5a of the cylindrical body 5 in a curved shape along the circumferential groove 5a. The antenna element 6 is connected to the transmitting circuit 3 via a lead wire 10 penetrating through the through hole 9 of the housing 1.

The contact probe device having the above structure is mounted on the main shaft by fitting the tapered portion 1a of the housing 1 into the mounting recess of the main shaft. Then, when the stylus 2 is displaced in the three-dimensional direction together with the main shaft and the stylus 2 contacts the work, the transmission signal indicating the contact is transmitted to the antenna element 6.
Sent from In this case, since the transmission signal is transmitted from the antenna element 6 which is a separate member from the stylus 2,
Unlike a conventional contact probe device using a stylus as an antenna element, the response of a contact signal does not become unclear due to the conductivity of the work, and the receiving side can reliably detect the presence or absence of the contact.

According to an experiment, the radio wave transmitted from the antenna element 6 has almost no directivity and can be received at an arbitrary angular position around the antenna. This is considered to be due to the mounting shape of the antenna element 6. It is desirable to set the length of the antenna element 6 to a half wavelength of the radio wave used, so that the maximum radiation efficiency can be obtained.

Further, since the antenna element 6 is covered with the cylindrical body 5, the cutting oil and the cutting debris do not adhere to the antenna element 6, and no noise is generated by the adhesion.

[0023]

According to the present invention, the contact signal between the stylus and the work can be securely transmitted wirelessly, and the measurement of the processed work can be performed quickly without any trouble.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of a contact probe device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a cylindrical portion of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Stylus 3 Transmission circuit 4 Battery 5 Cylindrical body 6 Antenna element

Continuation of the front page (56) References JP-A-62-287104 (JP, A) JP-A-62-237310 (JP, A) JP-A-59-7206 (JP, A) JP-A-3-71843 (JP) , U) Japanese Utility Model Showa 58-66310 (JP, U) Japanese Utility Model Application Hei 5-62807 (JP, U) Japanese Utility Model Utility Model Showa 64-8605 (JP, U) Japanese Utility Model Utility Model Hei 6-3323 (JP, Y2)

Claims (1)

(57) [Scope of request for utility model registration] 1. A contact probe device comprising a housing (1) attachable to a main shaft of a machine tool, wherein a contact signal between a stylus (2) attached to a tip of the housing (1) and a work is wirelessly transmitted. A resin cylinder (5) is provided on the outer periphery of the housing (1), and an antenna element (6) having a spring property is fitted on an inner peripheral surface of the cylinder (5). A contact probe device.