JPH0238346B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method and an apparatus for forming a grinding wheel used in a machine tool by electrical discharge machining, and in particular, a running wire is used as a forming tool for a grinding wheel. The grinding wheel is formed by performing electric discharge machining between the grinding wheel and its wire electrode using electrodes.

[Conventional technology and problems]

A device for performing grinding by attaching a grinding wheel to an NC machine tool is known in Japanese Patent Laid-Open No. 60-48257.
As a method and apparatus for forming a grinding wheel used in the NC machine tool, a method and apparatus for forming a grinding wheel by rotating the grinding wheel and bringing a single point diamond tool into contact with it are well known. In addition, methods and devices for molding by grinding together grinding wheels are also known.
When forming a grinding wheel using these methods, there is no problem if the grinding wheel bond, which is the binding material for the abrasive grains, is soft, but for example, if the grinding wheel bond is hard, such as a diamond grinding wheel with metal bond or cast iron bond, it may be difficult to retain the abrasive grains. If a strong grinding wheel is formed using the conventional method, the abrasive grains will be damaged, clogging will occur, and the grinding performance of the grinding wheel will deteriorate. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method and apparatus for efficiently forming a grinding wheel without causing such problems.

[Means of solution and action]

In the present invention, a grinding wheel is attached to the main shaft of an NC machine tool, and a wire electrode is made to run in an arcuate trajectory along a guide groove formed on the outer periphery of the wire electrode guide, and power is supplied to the rotating grinding wheel while the wire electrode is running. The wire electrode supported by the arcuate orbit portion of the wire electrode guide is brought into relative contact with the surface to be formed of the grinding wheel, and the power supply brush is rotationally driven to the grinding wheel in accordance with the contacting operation. A current of one polarity is supplied to the grinding wheel while making contact with the wire electrode, and a current of the other polarity is supplied to the running wire electrode, and the grinding wheel and the wire electrode are relatively connected by the NC device of the NC machine tool. The present invention provides a method of forming a grinding wheel into a desired shape by moving the grinding wheel and performing electric discharge machining between the two. Further, as an apparatus for carrying out the method, the present invention includes:
A grinding wheel attached to the main shaft of an NC machine tool, a wire electrode guide with a guide groove on the outer periphery that supports the wire electrode in the electrical discharge machining section so that it follows a circular arc trajectory, and a wire electrode guide that is supported by the wire electrode guide and is fed out and wound. A wire electrode that is run by a mechanism and can come into contact with the forming surface of the grinding wheel when the wire electrode guide runs along the circular arc trajectory portion, and as the wire electrode comes into contact with the grinding wheel. A power supply brush configured to contact the surface of the grinding wheel to supply power and be driven to rotate in a circular shape, a power supply electron to supply power to the traveling wire electrode, and supply machining fluid to the electrical discharge machining section. An NC machine comprising: a machining fluid supply device; and a power supply device for electric discharge machining that energizes the power supply brush and the electric power supply to perform electric discharge machining between a grinding wheel and a wire electrode.
A grinding wheel and a wire electrode are relatively moved by an NC device of a machine tool, and electric discharge machining is performed between a surface to be formed of the grinding wheel and a wire electrode running on an arcuate trajectory portion of the wire electrode guide. The present invention provides an apparatus for shaping a grinding wheel into a desired shape.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings. Fig. 1 is a perspective view showing the basic principle of the grinding wheel forming method and device of the present invention, Fig. 2 is a front sectional view of the electric discharge machining head, Fig. 3 is a right side view of the electric discharge machining head, and Fig. 4 The figure is a front sectional view showing the wire electrode feeding and winding mechanism and the power supply brush rotating mechanism inside the housing, FIG. , Figure 7 shows the device according to the present invention
It is a perspective view applied to a machine tool. The present invention is the first
As shown in FIG. 7, a grinding wheel 1 is attached to the tool spindle 3 of an NC machine tool 5 via a grinding wheel holder 2, and an anode from a power source for electrical discharge machining is supplied to the grinding wheel 1 using a power supply brush 18. , wire electrode guide 1
A cathode from a power source for electrical discharge machining is supplied to the wire electrode 14 supported by the grinding wheel 1 and run by the feeding and winding mechanism, and while electrical discharge machining is performed between the grinding wheel 1 and the wire electrode 14. The purpose is to relatively move the two to form the grinding wheel 1 into a desired shape. The relative movement between the grinding wheel 1 and the wire electrode 14 is controlled by the NC machine tool 5.
This is carried out using an NC device. For example, an electrical discharge machining head 10 is attached via a housing 30 to one end of a table that moves in the X- and Y-axis directions, and a grinding wheel 1 is attached to a tool spindle 3 that moves in the Z-axis direction.
is attached and relatively moved using NC commands. Further, the grinding wheel 1 is given a rotational force by the tool main shaft 3, and the power supply brush 18 that comes into contact with the grinding wheel 1 is formed into a circular shape from a conductive metal or the like that is elastically deformed and has a pressing force. In this embodiment, the power supply brush 18 directly contacts the grinding wheel 1 to supply power to the grinding wheel 1, but it is also possible to supply power to the grinding wheel 1 by bringing a non-rotating power supply brush of a different structure into contact with the grinding wheel holder 2. Needless to say, it's a good thing.

2 and 3 show the electrical discharge machining head section 10, in which the shaft section 12 of the wire electrode guide 11 is inserted and fixed into the guide base 13, and a V is formed on the circumference of the circular wire electrode guide 11. A groove is provided to prevent the wire electrode 14 from falling off. The wire electrode 14 performs electrical discharge machining between the wire electrode 14 and the grinding wheel 1 while running using the V-groove as a guide.
The traveling path of the wire electrode 14 is regulated by a plurality of guide rollers 15 and the like, so that it does not come off the wire electrode guide 11. An insulating bushing 16 is provided inside the wire electrode guide 11 and its shaft portion 12.
A power supply brush holding shaft 17 rotatably supported on the shaft is provided, and a power supply brush 18 for supplying power to the grinding wheel 1 is attached to the tip of the shaft 17 with a collar 19 in between and a nut 20
is fixed. A gear 21 is fixed to the rear end of the power supply brush holding shaft 17 and meshes with an intermediate gear 23 . When electrical discharge machining is performed between the grinding wheel 1 and the wire electrode 14, machining fluid is normally supplied. The machining fluid may be oil-based or water, depending on the purpose. In order to inject the machining fluid to the electrical discharge machining section, a machining fluid conduit 24 provided on the guide base 13 and the power supply brush holding shaft 17 is connected to the machining fluid injection port 2.
5, and the machining fluid connected to the arrow F by a conduit from a machining fluid supply device (not shown) is injected from the machining fluid injection port 25 to the electrical discharge machining section. Note that the tip of the machining fluid conduit 24 of the power supply brush holding shaft 17 is stopped with a plug 39. Furthermore, in this embodiment, since it may be better to temporarily remove the machining fluid when starting electric discharge machining or confirming the position, air can be injected into the electric discharge machining section. Air connected in the direction of arrow G by a conduit from an air supply device (not shown) passes through an air conduit 26 and an air guide groove 27 provided in the guide base 13, and is injected from an air injection port 28 to the electrical discharge machining section. The air injection port 28 has a semicircular packing 29 inserted between the upper part of the guide base 13 and the wire electrode guide 11, and is an air injection port that opens only in the semicircle of the electrical discharge machining section. The air is injected as needed, and intermittently injecting or stopping the air is controlled by an air switching valve (not shown).

Figures 4 to 6 show the wire electrode winding mechanism and the power supply brush 18 provided in the housing 30.
2 is a diagram showing a rotating device, etc. housing 30
The electrical discharge machining head section 10 shown in Fig. 2 is shown in the upper right corner of the
is installed. Inside the housing 30, a payout bobbin 31 on which the wire electrode 14 is wound is rotatably supported by a bracket 32 with a brake mechanism so as to apply a predetermined tension to the wire electrode 14. The wire electrode 14 is engaged with the wire electrode guide 11 via a power supply roller 34 supported by a bearing bracket 33, a guide roller 35, and the guide roller 15. Furthermore, the wire electrode 14 that has passed through the guide roller 15 passes through a guide roller 36 and is stopped by a winding bobbin 38 attached to a winding motor 37, and is wound up by the winding motor 37 during electrical discharge machining. Power is supplied to the wire electrode 14 by pressing a brush 42 with a spring 43 onto a power supply roller shaft 41 supported by an insulating bush 40 on a bearing bracket 33 to engage the power supply roller 34, as shown in FIG. wire electrode 1
4. The insulating bushing 44 is attached to the bearing bracket 33, and the power supply terminal 4 is inserted therein.
5, to which power is supplied by wiring from a power source for electrical discharge machining (not shown). The electric discharge machining power supply device is similar to a power supply device used in a general electric discharge machine, and is a known one.
The guide rollers 35 and 36 are rotatably supported on a roller shaft 46, and the roller shaft 46 is supported by an insulating bushing 47.
It is fixed to the housing 30 via.

The power supply brush rotation mechanism shown in FIG.
From the power supply brush rotation motor 50 attached to 0, its pulley 51, belt 52, pulley 53, gear shaft 54, power supply gear 55, intermediate gear 23,
The rotational force is transmitted to the power supply brush 18 via the gear 21 and the power supply brush holding shaft 17. The gear shaft 54 is rotatably supported on the housing 30 via an insulating bush 56. Power is supplied to the power supply brush 18 by connecting a wire from a power supply for electrical discharge machining (not shown) to a power supply terminal 57, and pressing a brush 60 supported by an insulating bush 59 attached to a bracket 58 against the gear shaft 54 with a spring 61. The gears 55, 23,
Power is supplied to the power supply brush 18 via the power supply brush holding shaft 17 and the power supply brush holding shaft 17 . In this embodiment, the power supply brush 1
Although power is supplied to the gear shaft 54 by a brush 60, it goes without saying that it is preferable to use a structure in which power is supplied by pressing the brush directly against the power supply brush holding shaft 17. Figure 6 is the arrow view of Figure 4.
2 is a partial cross-sectional view of a plane seen from the top, and the wire electrode 14 passing through the guide roller 35 is shown in FIG.
After passing through the aforementioned guide roller 15, wire electrode guide 11, and guide roller 15, and further through the guide roller 64 and guide roller 36, it is stopped by a winding bobbin 38 attached to a winding motor 37 and wound up.

In this embodiment, the anode is connected to the grinding wheel 1, which is the workpiece, from a power source for electric discharge machining, the cathode is connected to the wire electrode 14, which is the machining tool, and machining fluid is injected to the electric discharge machining part, and the grinding wheel 1 is heated. The surface is shaped (or shaped) to produce a highly accurate grinding wheel with a desired shape. The grinding wheel 1 shown in FIG. 1 is given rotation as indicated by arrow A and linear motion as indicated by arrow D.
While giving a slow rotation arrow B to the grinding wheel 8, the grinding wheel 1, which is rotating slowly, is pressed, and power is supplied to the grinding wheel 1. The wire electrode 14 supported by the wire electrode guide 11 is fed in the direction of arrow C, and electrical discharge machining is started at a position close to the grinding wheel 1. The portion of the wire electrode 14 where the wire electrode 14 contacts the grinding wheel 1 during electrical discharge machining is supported by the wire electrode guide 11, so that the wire electrode 14 does not bend and the feed C is applied to the wire electrode 14. Since electrical discharge machining is always performed using a new wire electrode 14, highly accurate molding is possible without errors caused by so-called electrode deflection or electrode wear. The relative movement between the grinding wheel 1 and the wire electrode 14 (arrow D, arrow E) is the NC of the NC machine tool.
It is controlled by the device's program instructions. In the basic principle diagram of FIG. 1, the positions of the wire electrode guide 11 and the power supply brush 18 are reversed from those of this embodiment, but this is to make the explanatory diagram easier to read, and the present invention is not limited to either direction. It's good to have it.

FIG. 7 is a perspective view of the present device installed on an NC machine tool, in which the grinding wheel 1 is installed on the tool spindle 3 of the NC machine tool 5 via the grinding wheel holder 2. A workpiece (not shown) is attached to the table 4 of the NC machine tool 5, and is subjected to grinding processing using the grinding wheel 1. A housing 30 of the device is attached to the side of the table 4. The present invention
When the grinding wheel is worn out after the NC machine tool 5 performs grinding, or when you want to change the shape of the grinding wheel, use this device to change the grinding wheel 1 while it is attached to the NC machine tool 5. It is intended to be molded (or shaped) into a desired shape.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when the grinding wheel becomes clogged or worn, it is necessary to dress or shape the grinding wheel, but this work is performed by the NC machine tool. This can be done with the grinding wheel attached, so
This work can be done in a short time and with high precision. Furthermore, since the base material such as metal bond or cast iron bond is formed by electrical discharge machining, there is an advantage that the abrasive grains are not destroyed and the grinding performance does not deteriorate. Furthermore, in the present invention, power is supplied to the grinding wheel from the power supply brush from the device of the present invention, so there is no need to supply power from inside the spindle of the NC machine tool, and the device has the advantage of being simple and inexpensive. In particular, since the power supply brush supplies power from the surface of the grinding wheel while rotating, the power supply brush always makes even and even contact with the surface of the grinding wheel, so there is no uneven wear, and therefore the power supply effect is improved. always performed stably,
Moreover, the effect of lengthening the service life of the power supply brush can be obtained.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the basic principle of the grinding wheel forming method and device of the present invention, Fig. 2 is a front sectional view of the electric discharge machining head, Fig. 3 is a right side view of the electric discharge machining head, and Fig. 4 The figure is a front sectional view showing the wire electrode feeding and winding mechanism and the power supply brush rotation mechanism inside the housing, FIG. 5 is a left side sectional view of the wire electrode feeding and winding mechanism, and FIG.
FIG. 7 is a perspective view of the device according to the present invention applied to an NC machine tool. 1... Grinding wheel, 3... Tool spindle, 5... NC
Machine tool, 10... Electric discharge machining head section, 11...
Wire electrode guide, 14...Wire electrode, 17...
...Power supply brush holding shaft, 18...Power supply brush, 2
1, 23, 55... Gear, 30... Housing, 31... Feeding bobbin, 34... Power supply roller, 35, 36... Guide roller, 37... Winding motor, 38... Winding bobbin, 50... ...Power supply brush rotation motor.

Claims (1)

[Claims] 1. In a method of shaping the shape of a grinding wheel by electric discharge machining, the grinding wheel is mounted on the main shaft of an NC machine tool, and a wire electrode is moved along an arcuate trajectory along a guide groove formed on the outer periphery of the wire electrode guide. The wire electrode supported by the arcuate track portion of the wire electrode guide is brought into relative contact with the forming surface of the grinding wheel, and the power supply brush is rotated as the electrode and the grinding wheel come into contact with each other. A current of one polarity is supplied to the grinding wheel while the wire is in contact with the grinding wheel, and a current of the other polarity is supplied to the running wire electrode, and the NC device of the NC machine tool contacts the grinding wheel. A method for forming a grinding wheel, characterized in that the shape of the grinding wheel is formed into a desired shape by applying relative movement between the wire electrode and performing electric discharge machining between the two. 2. In a device that shapes the shape of a grinding wheel by electric discharge machining, a grinding wheel attached to the main shaft of an NC machine tool and a wire having a guide groove on the outer periphery that supports the wire electrode in the electric discharge machining part so that it follows an arcuate trajectory. an electrode guide; a wire electrode that is supported by the wire electrode guide and is run by a feeding and winding mechanism, and that is capable of coming into contact with the surface to be formed of the grinding wheel when traveling along the circular arc trajectory portion of the wire electrode guide; , a power supply brush configured to supply power by contacting the surface of the grinding wheel as the wire electrode contacts the grinding wheel, and to be driven to rotate in a circular shape; and a power supply brush configured to supply power to the running wire electrode. a machining fluid supply device that supplies machining fluid to the electrical discharge machining section; and an electric discharge that energizes the power supply brush and the power supply to perform electrical discharge machining between the grinding wheel and the wire electrode. The NC machine tool is equipped with a processing power supply device.
A device relatively moves the grinding wheel and the wire electrode to perform electrical discharge machining between the surface to be formed of the grinding wheel and the wire electrode running on the circular arc trajectory portion of the wire electrode guide, and A grinding wheel forming device characterized by forming a grinding wheel into a desired shape.