JPH0236693Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a polishing tool that is attached to a polishing robot or the like and used for polishing complex curved surfaces of molds and the like.

``Prior Art'' Conventionally, when polishing a complex curved surface, polishing by rotating a circular grindstone while changing the inclination of the central axis requires complicated control of the polishing robot and becomes expensive. Therefore, the grindstone is made rotatable around two mutually orthogonal axes that are perpendicular to the axis of the grindstone, so that the grindstone follows the curved surface to be machined. An example of such a polishing tool is shown in FIG. In the figure, a circular grindstone 1 is connected to a shaft 4 via a universal joint that is rotatable around a fulcrum shaft 2 and a fulcrum pin 3 that are perpendicular to each other and are provided at a height h on its center line. . That is, the fulcrum shaft 2, the fulcrum pin 3, and the shaft 4 are perpendicular to each other, and the center of the shaft 4 and the center of the grindstone 1 are aligned.

"Problem to be solved by the invention" Polishing is performed by rotating the shaft 4 and applying the lower surface of the grinding wheel 1 to the surface to be processed. However, if the surface to be processed is small and complexly curved, the diameter D of the grinding wheel 1 should be made as small as possible. This is desirable. The whetstone 1 is made up of many abrasive grains, and these abrasive grains individually cut and polish the processed surface 5 shown in FIG. However, when h/D increases,
At a certain moment, the grindstone 1 rotates around the shafts 2 and 3 and tilts due to the cutting force F acting on a certain abrasive grain. Due to the force W pressing down the shaft 4, the inclined grindstone 1 attempts to rotate while receiving an upward reaction force P from the point of contact with the processing surface 5. Due to the rotational force of the grindstone 1 rotating at the rotational speed N and the rotation force due to the reaction force P, the grindstone 1 causes a precession movement in which the grindstone 1 sequentially changes its inclination direction and rotates, a so-called dish-dancing phenomenon (see Figure 2). , polishing becomes impossible, and scratches occur because only the contact points make strong contact with the processed surface 5. This phenomenon occurs due to the rotational force of the grinding wheel 1 with a large rotational speed N and the rotational force due to the reaction force P, so the force of precession is surprisingly large, so either lowering the rotational speed N of the grinding wheel 1 or The force W that presses the grinding wheel 1 toward the machining surface 5 is the cutting resistance.
The drawback was that it could not be contained unless it was made so powerful that the rotation of the engine decreased.

The purpose of the present invention is to eliminate this drawback and provide a polishing tool that can prevent the occurrence of the countersunk phenomenon by rotating the grindstone around an axis slightly eccentric from the center of the circular grindstone.

``Means for Solving the Problems'' The configuration of the present invention is that one side of a circular plate-shaped grindstone having a required thickness is used as a polishing surface, and the other side has a polishing surface on the outer periphery on the opposite side of the grindstone at an angle of 180 degrees with respect to the axis of the grindstone. The support shaft is provided with a protruding support part perpendicular to the polishing surface, and the support shaft is rotatably supported on this support part so that its axis passes through and is orthogonal to the axis of the grindstone. A pin that passes through the intersection of the center and the axis of the grinding wheel and has an axis perpendicular to the axis of the support shaft is provided, and the base end is rotatably supported by this pin, and It is characterized by having a shaft extending in the right angle direction, and rotating this shaft by attaching it to a polishing robot or the like.

``Function'' When the whetstone is rotated around its axis, the axis is eccentric from the center of the whetstone, so the whetstone slides sideways as it rotates around its axis, causing the whetstone to tilt due to the cutting force and begin to move in a precessional motion. However, this is canceled out by sideslip and the occurrence of precession can be suppressed.

"Embodiment" FIG. 3 shows details of an embodiment of the present invention. The circular plate-shaped grindstone 6 has a polishing surface on one side, the lower surface in the figure, and supports 7, 7 protruding from the outer periphery at 180 degrees opposite to the axis of the grindstone 6 at right angles to the polishing surface on the other surface. are doing. The support shaft 8 has its axis perpendicular to the axis of the grindstone 6, and is rotatably supported at both ends by the supports 7, 7. Therefore, the axis of the support shaft 8 is parallel to the polishing surface of the grindstone 6. The pins 9 fixed to both sides of the spindle 8 have their axial centers perpendicular to the axis of the spindle 8 at the center of the grindstone 6 . A fork 11 at the base end of a shaft 10 is rotatably connected to the pin 9 . The shaft 10 has its axial center within a plane that includes the axial center of the support shaft 8, and is provided eccentrically in one direction from the axial center of the pin 9 by an eccentric amount. That is, the shaft 10 constitutes a universal joint with respect to the grinding wheel 6 by the connecting portion between the supports 7, 7 and the spindle 8, and the connecting portion between the pin 9 and the shaft 10, and the shaft center is connected to the grinding wheel 6.
The axial center of the shaft 10 is eccentric from the axial center of the grindstone 6 by an amount of eccentricity at a position perpendicular to the polishing surface. Third
Figure a shows this state.

When the shaft 10 of the polishing tool shown in FIG. 3 is attached to a polishing robot or the like and rotated, and the polishing surface of the whetstone 6 is brought into contact with the work surface to perform polishing, the whetstone 6 rotates around the spindle 8 and the pin 9 relative to the shaft 10. Since it is freely rotatable, if the surface to be processed is a curved surface, it can be freely swung to conform to the curved surface. Furthermore, since the grinding wheel 6 is eccentric with respect to the shaft 10 by the amount of eccentricity, it rotates as if being swung around the shaft 10, so that the pressing force acting toward the center of the shaft 10 is continuously directed toward the center of the grinding wheel 6. Therefore, the grindstone 6 slides sideways in the direction of rotation while rotating around the shaft 10. Grinding wheel 6 due to cutting force F
When the grinding wheel 6 is inclined and about to enter a precession movement, the precession movement due to the reaction force P due to the inclination successively changes the inclination direction of the grinding wheel 6 so that the position of the grinding wheel 6 is lowered by 90 degrees in the opposite direction to the rotation direction of the grinding wheel 6. It works. However, whetstone 6
This is canceled out by the sideslip caused by swinging around the eccentric shaft 10, and the occurrence of precession can be suppressed.

According to actual results, if the eccentricity of the shaft 10 is set to 1 to 2 mm for a grinding wheel 6 with a radius of approximately 15 mm, the rotation speed of the grinding wheel 6 used for normal polishing will be 2,000 to 3,000 per minute.
In this case, the vibration caused by the unbalanced weight of the grinding wheel 6 rotating eccentrically is of a level that does not cause any actual damage to the polishing, and the plate-dancing phenomenon does not occur. The plate dancing phenomenon is
When the axes of the shaft 10 and the grinding wheel 6 are aligned, this occurs in an attempt to stabilize the torque received from the machined surface to be small, so there is no risk of this occurring when the grinding wheel 6 is swung around the shaft 10. was actually obtained.

In FIG. 4, another embodiment of the polishing tool is shown. In this case, the grindstone part has the same structure as the conventional example shown in FIG. 4 is rotatably held, or an eccentric shaft 13 is provided on a holding portion 12 to which the shaft 4 is fixed, eccentric by the amount of eccentricity with respect to the shaft 4, and parallel to the shaft 4. This polishing tool is used for polishing by pressing the grindstone 1 against the surface to be processed while rotating the eccentric shaft 13, and its operation is the same as that shown in FIG. 3.

In this case, the purpose can be achieved simply by attaching the eccentric shaft 13 to a conventional polishing tool.

``Effects of the invention'' As is clear from the above explanation, according to the invention, the diameter of the grinding surface of the grindstone becomes smaller, there is no risk of the plate-dancing phenomenon occurring due to an increase in h/D, and it is possible to reduce the diameter of the grinding surface of the grindstone. It has great practical effects and advantages, such as making it possible to polish complex curved surfaces and improving polishing efficiency.

[Brief explanation of drawings]

Figures 1a and b are a partial cross-sectional front view and side view of the conventional example, Figure 2 is an explanatory diagram of the operation of the conventional example, and Figures 3 a and b are a partial cross-sectional front view and side view of the embodiment. ,
FIG. 4 is a partially sectional front view of another embodiment. 1... Grindstone, 2... Fulcrum shaft, 3... Fulcrum pin,
4...Shaft, 5...Machining surface, 6...Whetstone, 7...Support part, 8...Spindle, 9...Pin, 10...Shaft, 1
1... bifurcated part, 12... holding part, 13... eccentric shaft.

Claims (1)

[Claims for Utility Model Registration] Shaped as a circular plate with the required thickness, one side is a polished surface, and the other side is supported perpendicularly to the polished surface on the outer periphery 180 degrees opposite to the axis of the polished surface. A whetstone with a protruding part, and both ends rotatably supported by the support part of the whetstone,
A spindle whose axis is orthogonal to the axis of the grinding wheel, and a spindle protruding from both sides through the intersection of the axis of the spindle and the axis of the grindstone, and whose axis is perpendicular to the axis of the spindle. a pin that is orthogonal to the pin, and a shaft whose base end is rotatably supported by the pin and whose axis is perpendicular to the axis of the pin in a plane that includes the axis of the support shaft and is eccentric. A polishing tool characterized in that the shaft is attached to a polishing robot or the like and rotated.