JPS6347587B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improvement of a friction polishing device, which uses a specially configured rotary polishing tool and enables stable polishing by controlling the rotation.

Conventionally, there are various types of rotary polishing devices, such as those using a grindstone tool and those using soft buffing, but the machining speed is low and they cannot be applied to arbitrary machining surfaces.

The present invention was devised in view of this point, and has two parts attached to the end face of a cylindrical body (including a solid body and a cylinder body) in the axial direction.
This method uses a polishing tool in which more than one polishing wire is planted, and this polishing tool is connected to a motor that rotates at high speed with a cylindrical body as an axis. It is then polished. During the polishing process, a detection device is provided that detects the contact friction state between the polishing wire and the workpiece by a change in electrical resistance between the polishing wire and the workpiece, and a detection signal is used to detect the contact friction between the polishing wire and the workpiece. By controlling the rotational speed, processing is performed so that the grinding pressure between the two is always constant.

The present invention will be described below with reference to an embodiment of the drawings. FIG. 1 shows an embodiment of the polishing tool, in which a is a diagram showing a static state and b is a diagram of a rotating state. Reference numeral 1 denotes a cylindrical body, 2 a rotating shaft, and 3 an abrasive wire that is planted parallel to the axial direction of the cylindrical body or with its tip converging.
This wire material includes piano wire, brass wire, CuBe wire, iron wire, WC wire, TiNi wire, _B4C wire, FeCr wire, WC coated wire, _B4C coated wire, and even hard materials such as diamond grains and BN grains. Wires to which materials are attached, glued, painted, or coated, plastic wires, glass wires, and other abrasive wires are used. This wire is used as round wire, square wire, etc., and the wire diameter is usually 0.1 to 0.5
It is about mmφ to 1mmφ. The number of wire rods to be planted in the cylindrical body should be two or more, and if there are many, about 20 wire rods should be planted for use. Incidentally, if the number is too large, the beating effect will be small and the polishing performance will also be reduced. Of course, it also depends on the radius of the cylinder. It is best to plant symmetrically around the central axis to allow for smooth rotation. If there are many, plant them around the circumference. Using a chuck type for fixing the planting is convenient because the wire can be easily replaced and repairs can be made after wear and tear. As shown in figure b,
When the wire rod 3 is rotated at high speed, the wire rod 3 spreads out, and the side surface or tip surface of the wire rod 3 is brought into contact with the surface to be processed and polished by contact friction. The rotational speed is set to a desired value of about 500 to 20,000 rpm so that the wire 3 is sufficiently spread.

FIG. 2 shows a polishing apparatus configured to polish a workpiece using the polishing tool, in which a rotating shaft 2 is connected to a motor 4 to provide desired high-speed rotation. 5
7 is a power source for rotationally driving the motor 4; 6 is an object to be polished; and 7 is a power source to detect the contact friction between the abrasive wire 3 and the object 6; 8 is a detection resistor thereof, and 9 is a control circuit for controlling the motor drive power source based on a detection signal. The control is to control the rotation speed of the motor so that the grinding pressure between the polishing wire and the workpiece is always constant.

The polishing device composed of the polishing tool, rotary motor, etc. described above performs polishing by manually moving the processing surface of the workpiece 6 or by attaching it to a table of a mechanical device and moving it. It's okay. Of course, the processing surface of the workpiece may be moved by NC control or program control.

The processing action of the polishing tool is as follows. Due to the high-speed rotation of the polishing tool, the wire rod 3 spreads around the planted area, and when the rotation is stopped, the wire rod 3 returns to its original state and narrows. Therefore, the configuration is such that the spread of the wire 3 can be controlled by controlling the rotational speed. When the wire rods 3 that are spread by the rotation are brought into contact with the processing surface of the workpiece 6 as shown in the figure, each wire rod 3 planted in the cylindrical body is bent by the rotation and becomes bent and fitted to the polished surface. They touch, rub, and pass. Each wire 3 leaves the abrasive surface with each revolution, spreads out due to rotational centrifugal force, rotates with kinetic energy stored, and collides with the abrasive surface.
While giving a beating, it fits onto the polished surface and creates contact friction.

The friction state of the wire 3 is such that when using a conventional whetstone polishing tool, the contact area increases considerably compared to point contact depending on the shape of the polishing surface, and the wire rod 3 is fitted over a wide area and then the next These significantly increase the polishing speed due to the contact friction passing from one to the next. Efficient polishing is carried out by the contact collision of each wire 3 with the polishing surface and the elastic tapping action. During this polishing, the polishing portion is moved by relative movement between the polishing tool and the workpiece, so that the entire polishing surface is uniformly polished.

As for the polishing action, highly efficient finish polishing can be performed as described above just by the frictional action of the wire 3 itself, but hard abrasive grains coated and adhered to the surface of the wire 3 or free abrasive grains supplied to the polishing gap can be used. Furthermore, by using a polishing action such as a polishing liquid, an even more effective polishing action can be achieved. The polishing liquid is supplied by spouting the polishing liquid mixed with abrasive grains, if necessary, along the surface of the wire 3 from, for example, inside the cylindrical hollow cylindrical body. Further, by using an electrolytic solution as the polishing solution and further supplying electricity, an electrolytic polishing action can also be used.

However, during machining, if the contact friction between the polishing tool and the workpiece changes for some reason, the rotational speed of the polishing tool 1 and the spreading state of the wire 3 will change, the grinding pressure will change, and the condition of the polished surface will change. The amount of processing changes and uniform polishing becomes impossible.

Therefore, the present invention attempts to detect the contact friction state between the wire rod and the workpiece as a change in the current-carrying electrical resistance between the two, and based on this detection, control the rotational speed of the motor so that the grinding pressure is kept constant. It is something to do.

That is, the electrical resistance, which changes depending on the contact friction state between the abrasive wire 3 and the workpiece 6, is detected by applying current between the two from the power source 7, and the circuit current is detected as a voltage drop across the resistor 8 terminal. That is, if the contact resistance increases, the signal voltage of the resistor 8 will decrease, and on the other hand, if the contact resistance decreases due to strong contact, the signal voltage will increase. Therefore, this signal is applied to the control circuit 9 to control the motor drive power source 5 so that the grinding pressure between the abrasive wire 3 and the workpiece 6 is constant. The polishing wire 3 of the polishing tool spreads due to rotation, that is, due to rotational centrifugal force, and this spreading force is applied to the surface of the workpiece 6 for polishing. Therefore, by controlling the rotational speed of the motor 4, the grinding pressure can be adjusted. can be controlled. Increasing the rotational speed increases the contact pressure and the frictional force, which increases the grinding pressure. Conversely, if the rotational speed is lowered, the grinding pressure will be lowered.

Therefore, by controlling the rotational speed of the motor so that the grinding pressure is always constant, the contact friction, collision friction, etc. of the wire 3 against the processing surface 6 can be controlled at a constant level, and the processing action can be kept constant. The entire machined surface can be polished to a uniform surface roughness and uniform dimensional accuracy, resulting in extremely efficient polishing.

As described above, the present invention is a polishing tool in which two or more polishing wires are planted on the end face of a rotating cylindrical body in the axial direction, preferably parallel to each other or with their tips converging, and which are rotated at high speed by a rotary motor. As a result, the abrasive wire spreads out, and this spread abrasive wire is brought into contact with and rubbed against the processing surface of the workpiece to perform polishing, so the contact friction and striking collision friction provide a high polishing effect. In addition to being able to perform efficient polishing, a detection device is installed that detects the state of contact friction between the polishing wire and the workpiece by detecting changes in electrical resistance between the two, and the rotation of the rotary motor is controlled by the detection signal. Since the speed is controlled so that the grinding pressure is always constant, the contact friction, collision friction, etc. mentioned above can be controlled at a constant level, the polishing action can be continued at a constant level, stable polishing can be achieved, and the entire machined surface can be polished. A uniform polished finish can be achieved with constant surface condition and dimensional accuracy.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the polishing tool of the present invention, in which a is a diagram showing a static state, b is a diagram showing a rotating state, and FIG. 2 is a diagram showing an embodiment of the entire apparatus of the present invention. DESCRIPTION OF SYMBOLS 1... Cylindrical body, 2... Rotating shaft, 3... Wire for polishing, 4... Motor, 5... Drive power source, 6... Workpiece, 7... Energizing power source, 8... Detection resistor, 9 ……
control circuit.

Claims (1)

[Claims] 1. A polishing tool in which two or more polishing wires are distributed on the end face of a cylindrical body in a rotationally balanced manner on a circumference concentric with the center of rotation, and are mounted parallel to the axial direction of the cylindrical body or tapered at the tip; A rotary motor that rotates the polishing tool at high speed around a cylindrical body is provided, and the side surface of the polishing wire rotating at high speed is brought into contact with the surface of the workpiece to be polished by friction. A detection device is provided that detects the contact friction state between the polishing wire and the workpiece by a change in electrical resistance between the workpieces, and the rotation speed of the rotary motor is adjusted based on the detection signal of the device. A polishing device equipped with a control circuit that controls the grinding pressure between the workpiece and the workpiece to be constant.