JPH0217801Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention particularly relates to a tool position detection device for a machine tool.

(Prior Art) As shown in FIG. 2, in a machine tool M such as an NC or MC, a tool position detection device 30 is usually attached to the tool holder 21, and this detects the relative position of the tool and the workpiece W. Detect. For example, each coordinate value at this time is input to a predetermined control device to control the position of the workpiece W and the like.

The position detection device 30 used in this case consists of a shank part 31 attached to the tool holder 21 and an arbor part (contact detection part) 32.
A contact portion 33 having a standard diameter formed at the tip of the contact portion 33 is brought into contact with the workpiece W, and a circuit 35 is connected to a battery 34 built in the shank portion 31, that is, a light emitter (lamp etc.) 36, an arbor portion 32, and a contact portion 33. , the workpiece W, the table 23, the machine body 24, the spindle portion 25, and the tool holder 21 form a closed circuit and are energized. Note that, at this time, the light emitting body 36 is lit by energization.

Conventionally, in the position detection device 30 of such a process, when focusing on the configuration of the arbor part 32, the contact part 33 is generally formed in a cylindrical shape, the outer circumferential surface of which is finished with high precision, and the arbor part 32 has a high rigidity as a whole. It forms.

However, such arbor part 32 and contact part 3
3 has no cushioning properties at all, so the operator must
2 or when the workpieces W are brought close to each other, the two accidentally collide or come into contact with each other under strong pressure and the contact portion 3
3 is often deformed, reducing position detection accuracy.

Therefore, in order to improve this point, a spring is built into the main body of the arbor part, and the other contact part 33 is formed into a steel ball of a reference diameter, and this steel ball is used to define the tip of the main body of the arbor part. A position detection device that is elastically held in place by being pulled into position has also been proposed.

(Problem to be solved by the invention) However, in the conventional position detection device described above, since the steel ball moves relative to the main body of the arbor part, the seat surface of the steel ball that occurs at the tip of the main body of the arbor part Foreign matter such as dust and iron powder can easily get into the gaps between the steel balls. In this case, since the steel ball is urged against the main body of the arbor portion with a considerably large tensile force, cleaning is extremely difficult, resulting in problems such as a decrease in detection accuracy or a tendency to cause a failure.

The present invention eliminates such defects and provides a tool position detection device that always maintains high detection accuracy, is easy to configure, easy to assemble, is low cost, and is highly reliable and less likely to break down. .

(Means and operations for solving the problems) In order to solve the above problems, the present invention particularly includes a contact detection section 2 and a shank section 3 as shown in FIG. Machine tool M shown in
By attaching it to the tool holder 21 of the tool holder 21, it detects the energization of the circuit 35 due to the contact between the contact detection part 2 and the workpiece, and detects the relative position of the tool and the workpiece. The structure includes a steel ball 4 that is brought into contact with the workpiece in the contact detection section 2, and an attraction holding section 6 that has a built-in magnet 5 and that attracts and holds the steel ball 4 in a fixed position. It is characterized in that it can be easily attached to and detached from the holding part 6.

(Embodiments) Below, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional side view of a position detection device according to the present invention.

In the figure, the shank portion 3 includes an internally hollow cylindrical body 7, and one end (upper end) of this cylindrical body 7 is closed with a cap 8. On the other hand, the upper part 10 of the contact detection part 2 is inserted into the interior through the opening at the other end (lower end) of the cylindrical body 7 via the insulating sleeve 9 and fixed.

The contact detection unit 2 includes the upper part 10 and the upper part 10.
It consists of a lower part 11 integrated into the lower end of the. Upper 10
is formed into a cylindrical shape with an open top end, into which a holding lamp (light emitter) 13 is inserted through a socket 12 and elastically supported by a coil spring 14. Furthermore, inside is a battery 1 housed in a cylindrical battery case 15.
6 and 16 are inserted, and the positive terminal of this battery is supported by the cap 8. With such a structure, the battery 16,1
The positive pole of 6 is connected to the shank part 3 via cap 8.
and the negative pole is connected to lamp 1.
3. Connected to the contact detection section 2 via a socket 12 and a spring 14. Note that the shank portion 3 and the detection portion 2 are electrically insulated by the sleeve 9. Further, the upper part 10 and the sleeve 9 at the position of the lamp 13 are provided with a lamp 13 from the outside.
A through hole 17 is provided through which the lighting can be visually confirmed.

On the other hand, the lower part 11 of the detection part 2 is a round bar-shaped support shaft 1.
8, a suction holding part 6 provided at the lower end of this support shaft 18, and a steel ball 4 suctioned and held by this holding part 6. The support shaft 18 consists of an upper shaft 18a with a relatively small diameter and a lower shaft 18b with a large diameter, and the lower shaft 18b has a cylindrical circumferential surface finished with high precision and a diameter dimension set so that the steel ball 4 can be separated from the shaft 18a. In some cases, it can function as a conventionally commonly used contact portion. On the other hand, the lower part of the lower shaft 18b has a suction holding part 6.
will be established. The adsorption/holding part 6 includes a recess 19 formed on the lower end surface of the lower shaft 18b with a circular cross section and notched upwardly and having a diameter smaller than the diameter of the lower shaft 18b, and a permanent magnet fixedly attached to the ceiling portion which is the bottom of this recess 19. 5, and a holding surface 20 that is in surface contact with the spherical surface of the steel ball 4 formed on the opening side of the recess 19.

The steel ball 4 is made to have a diameter larger than at least the diameter of the lower shaft 18b, and is formed to have a predetermined reference diameter.

With this configuration, the magnetic flux of the magnet 5 is focused on the holding surface 20, and the steel ball 4 is attracted by a strong attractive force.
At the same time as the steel ball 4 is attracted to the holding surface 20, the steel ball 4 becomes detachable from the holding surface 20. Further, the lower shaft 18b and the steel ball 4 are also electrically connected.

In addition, the explained shank part 3, upper part 9, lower shaft 1
8b, the centers of the steel balls 4 are all arranged on the same axis.

Although the embodiments have been described in detail above, the present invention is not limited to the above embodiments, and the shape, detailed structure, material, etc. can be implemented as desired. For example, any light emitting body such as a lamp LED may be used, and the magnet may be an electromagnet using a battery. Moreover, in this case, a type in which the strength of the electromagnet can be adjusted may be used. Furthermore, although the present invention has been disclosed for detecting the position of a tool in a machine tool, it can be applied to various technical fields as a position sensor for detecting the position of a tool in a machine tool.

(Effects of the invention) As described above, the tool position detection device according to the invention has a built-in steel ball that contacts the workpiece and a magnet in the contact detection part to attract and hold the steel ball in a fixed position. The following remarkable effects can be obtained because of the suction holding section.

Even if an unexpected collision or strong pressure is applied to the steel ball during work, the steel ball can be detached from the suction holding part on the main body side, so there will be no damage to the steel ball and high precision can be maintained.

Even if foreign matter gets into the gap created between the anti-adsorption and holding parts when the steel ball is detached, it can be easily cleaned by completely removing the steel ball, and high-precision detection is always possible. .

It has a simple structure, is easy to manufacture, does not cause any breakdowns, and has excellent low cost and reliability.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a position detection device according to the present invention, and FIG. 2 is a schematic side view showing the position detection device attached to a machine tool. In the drawings, 1...position detection device, 2...contact detection section, 3...shank section, 4...steel ball, 5...magnet, 6...adsorption holding section, M...machine tool, 21...
...Tool holder, 35...Circuit, W...Workpiece.

Claims (1)

[Claims for Utility Model Registration] 1. A contact detection part and a shank part are provided, and by attaching the shank part to a tool holder of a machine tool, energization of a circuit due to contact between the contact detection part and a workpiece is detected, and the tool and workpiece are connected. In a tool position detection device that detects the relative position of a workpiece, the contact detection section includes a steel ball that is brought into contact with the workpiece, and an attraction holding section that has a built-in magnet and that attracts and holds the steel ball in a fixed position. A tool position detection device comprising: 2. The tool position detecting device according to claim 1, wherein the suction holding part has a recess having a diameter smaller than the diameter of the steel ball, and a magnet is fixed to the bottom of the recess. 3. The tool position detecting device according to claim 1, wherein the open end of the recess in the suction holding section forms a holding surface that makes surface contact with the spherical surface of the steel ball.