JPH074736B2 - How to detect core drill status in core drill machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a core drill machine, in which the core drill is close to a work, or the core of the core drill is clogged with grinding powder or the cutting edge is worn. It relates to a method of detecting.

[Conventional technology]

In a core drill machine, the drill is made to approach a work by fast-forwarding, the time when the tip of the drill comes into contact with the work is detected, and this drill is fed by grinding.

This detection utilizes the fact that the work is a conductive material,
Similarly, when a core drill made of a conductive metal material comes into contact with the conductive work, it is detected by electrical means.

[Problems to be Solved by the Invention]

However, if the work is a non-conductive material such as ceramics or so-called new glass, the above detection method
There is a problem that the contact between the drill and the work cannot be electrically detected.

On the other hand, a general core drill is a tool for drilling a work by removing the core while flowing a cutting fluid or a grinding fluid into a hollow core hole, but with known core drills, ceramics, new glass, crystals, Drilling holes of very small diameter in brittle materials such as oxides is virtually impossible.

The inventor of the present invention has developed a core drill capable of drilling even a hole having an extremely small diameter in the brittle material as described above.

In this drill, the drill body is formed by a small-diameter hollow shaft that forms a hollow shaft, and a diamond to be a grinding blade is fixed to the tip by electrodeposition etc., but the developed core drill itself has an extremely small diameter. Therefore, if the approach to the work is detected by the conventional touch method, the cutting edge may be damaged. Also, when drilling holes in opaque materials such as ceramics, the blade edge is not clogged or worn during drilling, that is, the state of the hole drilling process cannot be visually recognized. Continuing, the grinding fluid from the core hole does not reach the grinding surface due to clogging or wear, and eventually grinding is performed without the supply of the grinding fluid, which may burn the cutting edge.

The present invention is a method of non-contact detection of the approach of the work of the cutting edge in a core drill machine that does not cause the above problems,
Alternatively, the problem was to develop a method for non-visually detecting clogging and wear of the cutting edge.

[Means for Solving the Problems]

The structure of the present invention made in order to solve the above-mentioned problems is to form a grinding fluid chamber in communication with a core hole of the core drill in a mounting head that attaches a core drill and rotates integrally with the drill, and to a grinding fluid in this chamber. And a communication port communicating with the chamber are formed while the core drill is sending the workpiece toward the workpiece, the supply pressure of the grinding fluid supplied to the supply port and the communication port. The first feature is to detect the pressure in the chamber from the two and compare the two detection values, and detect when the two detection values are substantially equal as the drill tip and the workpiece are close to each other, A grinding fluid chamber communicating with the core hole of the core drill is formed in the mounting head that attaches the core drill and rotates integrally with the drill, and the grinding fluid is supplied to this chamber. And a communication port that communicates with the chamber, while the core drill is being rotated to make a hole in the workpiece, the supply pressure of the grinding fluid supplied to the supply port and the communication port. The pressure in the chamber is detected from the above and both detection values are compared, and when both detection values are almost the same, whether the core drill blade edge is clogged,
Alternatively, the second feature is to detect that the cutting edge is worn and detect this.

[Action]

The grinding fluid supplied to the hollow core hole of the core drill through the grinding fluid chamber is supplied to the core drill when it flows out from the tip of the core drill without any resistance. The pressure in the chamber is lower than the pressure. However, when the tip of the core drill approaches the work and the outflow resistance of the grinding fluid increases, the pressure in the grinding fluid chamber increases. Further, when the core hole is clogged with the core drill, or the grinding fluid cannot flow out from the tip of the core hole due to clogging of the core hole or wear of the cutting edge, the pressure in the chamber increases.

Therefore, if the pressure in the grinding fluid chamber is monitored, it is possible to detect that the outflow resistance of the grinding fluid at the tip of the core drill increases for some reason.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of essential parts showing an outline of a core drill machine to which the method of the present invention is applied.

In the figure, 1 is the spindle part of the core drill machine, which is 1a.
Is a spindle connected to a motor (not shown), and 1b is a spindle case that rotatably supports the spindle 1a.

Reference numeral 2 denotes a spindle head integrally formed on the tip end side of the spindle 1a, in which a grinding fluid chamber 2a is formed, and the tip end side of the head 2 has a grinding fluid communicating with the chamber 2a on its rotation axis. A chuck 2c which is formed in the passage 2b and is used for attaching and detaching the core drill 3 is provided. Reference numeral 3a is a core hole provided on the center axis of the core drill 3 so as to penetrate therethrough, and serves as a passage for the grinding fluid.

The spindle head 2 in which the chamber 2a is formed is rotatably held by the head holder portion 4 integrated with the spindle case 1b via a seal material 4c.

Thus, in the head holder portion 4 of the spindle case 1b,
A supply passage 4a for supplying the grinding fluid into the chamber 2a and a detection passage 4b for detecting the pressure of the grinding fluid in the chamber 2a are formed on the side surface thereof.

On the other hand, the grinding fluid chamber 2a formed in the spindle head 2 has passages 21a, 21b communicating with both the passages 4a, 4b.
Is formed via a groove 21c formed on the outer peripheral surface of the chamber 2a.

With the above configuration, the grinding fluid supplied from the outside to the grinding fluid supply passage 4a enters the chamber 2a through the outer peripheral groove 21c of the spindle head 2 and the supply passage 21a, and enters from the chamber 2a to the tip side of the spindle head 2. While being discharged from the tip of the core hole 3a in the core drill 3 to the outside of the drill 3 via the passage 2b, a part of the grinding fluid in the chamber 2a flows into the detection passage 4b through the passage 21b.

Therefore, in the present invention, as shown in FIG. 2, in the supply passage 4a of the head holder portion 4 of the spindle case 1b, the cock 5a,
A grinding fluid supply pump 6 is connected through a filter 5b and the like by a pipe 5c, a pressure sensor 7 is inserted in the middle of this pipe 5c, and a pipe 8 is provided in a detection passage 4b in the head holder 4.
The pressure sensor 9 was connected via the to form an example of the detection circuit of the present invention.

By doing so, the supply pressure of the grinding fluid discharged from the core hole 3a of the core drill 3 via the passage 2b of the chamber 2a can be constantly detected by the pressure sensor 7, and the pressure of the grinding fluid inside the chamber 2a can be controlled. The pressure sensor 9 always detects. Incidentally, the pipe 8 of the pressure sensor 9 is an integral pipe so that the fluctuation of the supply source pressure of the grinding fluid itself does not have a great influence on the pressure sensor 9.

Here, as the pressure sensors 7 and 9, those which show the detected pressures P ₁ and P ₂ by electric signals (voltages) are used, but the model of the sensor and the shape of the output signal can be selected arbitrarily.

In the pressure sensors 7 and 9 described above, the pressure P ₁ detected by the pressure sensor 7 indicates the supply pressure of the grinding liquid, and the pressure P ₂ detected by the pressure sensor 9 is the grinding liquid discharged from the core hole 3 a of the core drill 3. Shows the release state of.

That is, when the grinding fluid is released from the core hole 3a only by the flow resistance of the core hole 3a, the detection pressure P ₂ (internal pressure of the chamber 2a) is the detection pressure P ₁ (grinding fluid Supply pressure).

However, when the tip of the core hole 3a is closed, for example, the grinding fluid is not discharged from the core hole 3a, so the detected pressure P ₂ gradually increases, and this pressure P ₂ and the detected pressure P ₁ become substantially equal.

The present invention focuses on the relationship between the discharge state of the grinding fluid discharged from the core hole 3a and the detected pressures P ₁ and P ₂ as described above, when the tip of the core drill 3 approaches the work W immediately before contact. The detection is performed immediately when the core hole 3a of the core drill 3 is clogged with grinding powder or the tip is worn and the grinding fluid is no longer discharged.

Hereinafter, this point will be described.

The supply pressure of the grinding fluid can be arbitrarily set by adjusting the discharge capacity of the pump 6 and the like. The preset supply pressure is converted into an electric signal by the pressure sensor 7, and this signal is supplied to the setting unit 11, for example. Supply pressure is set to pump 6,
It may be supplied to the setting unit 11 from there.

On the other hand, the pressure detected by the pressure sensor 9 is also converted into an electric signal and supplied to the comparison unit 12. In the comparison unit 12, the pressure P ₁ supplied from the setting unit 11 and the pressure supplied from the pressure sensor 9
Comparing the P _2, the predetermined value is a comparison value, for example, to output Once become substantially equal numbers, are formed by attaching a output value setting unit 12a for setting an output value.

The output of the comparison unit 12 is used to control a spindle feed motor (not shown) or a spindle motor (not shown) for stopping the feed of the spindle 1a or stopping the rotation of the spindle 1a. To be done.

In the present invention, the spindle rotation is stopped together with the control for stopping the spindle feed by detecting when the tip of the core drill 3 approaches the work W, and the spindle feed detected when the tip of the core drill 3 is clogged or worn. In order to distinguish from the control to be performed, the following is done as an example.

That is, it detects when clogging occurs during drilling,
In order to stop the spindle feed and rotation at the same time, it is preset in the comparison unit 12 on the condition that the spindle motor is rotating.

With this configuration, the spindle motor can detect the detected pressure P ₁ and P _{2 according to} the predetermined relationship even when the detected pressure approaches the workpiece and when the cutting edge is clogged under the same pressure condition. It is possible to control the spindle feed and rotation to stop at the same time when the rotation occurs.

In the above embodiment, the case where the pressure sensors 7 and 9 are separately provided has been described, but the pressures P ₁ and P ₂ may be detected respectively, and at the same time, the difference between the pressures may be taken out through a differential pressure amplifier. .

Alternatively, the grinding feed motor of the spindle may be controlled while constantly monitoring the pressure P ₂ during grinding to enable drilling by automatic feed.

〔The invention's effect〕

The present invention is as described above, and in the core drill machine, since it is possible to detect immediately before the tip of the core drill approaches and contacts the work, the tip of the core drill in a core drill machine having an extremely small diameter is most suitable for the work. It becomes possible to stop the feed of the core drill at the approached non-contact position.

In addition, when the tip of the core drill is clogged or abraded during grinding and it becomes impossible to discharge the grinding fluid, it can be detected based on the pressure detected by the grinding fluid. Even if the grinding state is a drilling process that is not visible from the outside,
Allows drilling with a core drill without causing processing defects.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an outline of a core drill machine to which the method of the present invention is applied. 1 ... Spindle part, 1a ... Spindle, 1b ... Spindle case, 2 ... Spindle head, 2a ... Grinding liquid chamber, 21a, 21b ... Chamber 2a passage, 21c ... Chamber outer peripheral groove, 2b ... … Spindle head grinding fluid passage, 2c
…… Drill chuck, 3 …… Core drill, 3a …… Core hole, 4 …… Spindle case head holder, 4a ……
Grinding fluid supply passage, 4b ... Chamber internal pressure detection passage

Claims (2)

[Claims] 1. A grinding fluid chamber communicating with a core hole of a core drill is formed in a mounting head for mounting a core drill and rotating integrally with the drill, and a supply port for supplying the grinding fluid to the chamber and the chamber. While the core drill is being sent toward the workpiece, the supply pressure of the grinding fluid supplied to the supply port and the pressure in the chamber from the communication port are detected to detect both. A method for detecting a core drill condition in a core drill machine, which compares detected values, and detects when the detected values are substantially equal as the drill tip and the work piece are close to each other. 2. A grinding fluid chamber communicating with a core hole of a core drill is formed in a mounting head for mounting a core drill and rotating integrally with the drill, and a supply port for supplying the grinding fluid to the chamber and the chamber. While the core drill is being rotated to make a hole in the workpiece, the supply pressure of the grinding fluid supplied to the supply port and the pressure in the chamber are detected from the communication port. Then, the two detection values are compared, and when the two detection values are almost equal, the cutting edge of the core drill is clogged, or
A method for detecting a core drill condition in a core drill machine, which detects that the cutting edge is worn.