JP2006088250A - Polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To machine a surface to be worked into a flat surface or a curved surface by keeping the polishing pressure as desired, stabilizing the polishing condition, restraining heterogeneous polishing result, and facilitating securing the shape accuracy and controlling the polishing conditions for securing the shape accuracy. <P>SOLUTION: This polishing device polishes a surface to be worked W1 of a workpiece W by applying polishing pressure to a polisher 3. The polishing device 1 has air chambers 5, 6 where a fluid flows. The polishing device 1 includes: a pressure converting means 7 for converting the fluid pressure of a fluid applied to the air chambers 5, 6 to pressing force serving as the polishing pressure to a spherical tool 3; a pressure control means 8 for freely controlling the fluid pressure of the fluid to arbitrary pressure; a pipe line 9 for introducing the fluid, the pressure of which is controlled by the pressure control means 8, into the pressure converting means 7; and a releasing means 10 for releasing the fluid to a space having lower pressure than the controlled pressure of the fluid in at least one or more out of the air chambers 5, 6 of the pressure converting means 7 or the downstream pipeline passing through the pressure converting means 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a polishing apparatus for processing an optically good flat surface, curved surface, or the like of an element having an optical surface such as a lens or a prism, or a molding die for molding them.

Conventionally, various polishing apparatuses for polishing a flat surface or a curved surface are known (see, for example, Patent Documents 1 and 2).
As shown in FIG. 4, this type of polishing apparatus places and fixes a workpiece 61 on a work table 60 that can be freely controlled in three dimensions based on processing data by a control device (not shown) and a posture driving device. . A polisher 63 having a polisher shaft 62 is fastened and fixed to a spindle 64 by a chuck 65, and the spindle 64 can be rotated by a motor drive spindle 66. The motor drive spindle 66 is integrally fixed to an air static pressure bearing 67, and the air static pressure bearing 67 is inserted and guided through a guide shaft 69 fixed to the polishing head base 68.

The motor drive spindle 66 is fixed to the piston shaft 71 via the pressing force detector 70, and the piston 72 is integrated with the piston shaft 71. The piston 72 forms an upper air chamber and a lower air chamber of the cylinder 73, and receives a vertical pressure by the piston 72. Further, the piston 72 and the cylinder 73 have a static pressure bearing structure and have minimal sliding resistance.
The upper end of the piston shaft 71 is coupled to a fishing line 74, the fishing line 74 is guided by a pulley 75 that is rotatably provided on the polishing head base 68, and the other end is coupled to the upper end of a weight hanging shaft 76. The weight hanging shaft 76 is inserted into an air static pressure bearing 77 fixed to the polishing head base 68. A balance weight 78 is screwed and fixed to the bottom threaded portion of the weight hanging shaft 76.

In the upper air chamber of the cylinder 73, there is a pressing port 79, which is connected to the pressing air solenoid valve 80 by a pipe line. Further, the pressure air solenoid valve 80 is connected to the electropneumatic pressure control valve 81 and a pneumatic circuit is assembled so as to be connected to the air source 83 via the original pressure control valve 82. The electropneumatic pressure control valve 81 is controlled by a control device (not shown) and can freely control the air pressure.
The lower air chamber of the cylinder 73 has an elevating port 84 and is connected to the elevating air electromagnetic valve 85 through a pipe line. Further, the lift air solenoid valve 85 is connected to the air source 83 via the original pressure control valve 82. The pressing force detector 70 can detect the pressing force applied to the polisher 63 from the piston shaft 71 via the motor drive spindle 66, the spindle 64, the chuck 65, and the polisher shaft 62.
As described above, the polishing apparatus is configured.

Next, the case where the polishing process is performed by the polishing apparatus configured as described above will be described.
The work table 60 is maintained by the posture driving device (not shown) and the control device of the posture driving device while maintaining the posture of the processed workpiece 61 so that the processed workpiece 61 always contacts the polisher 63 in the normal direction based on the processing data. And controlled to scan the polishing site.
The polisher shaft 62 of the polisher 63 is fastened and fixed to the spindle 64 by the chuck 65, and transmits the movement of the spindle 64 rotated by the motor drive spindle 66 to the polisher 63. A polishing motion is relatively generated by the rotation of the polisher 63 and the posture control operation of the workpiece 61 to perform polishing.
At this time, the motor-driven spindle 66 is guided along the guide shaft 69 via the air hydrostatic bearing 67, so that the motor-driven spindle 66 moves up and down with a very slight sliding resistance.

  Since the motor drive spindle 66 is connected to the piston shaft 71 via the pressing force detector 70, the motor driving spindle 66 is pressed by the piston 72 and the pressing force is detected by the pressing force detector 70. The pressure of the piston 72 is generated by the air supplied under pressure control to the upper air chamber of the cylinder 73. The air supplied to the upper air chamber is reflected by the control device (not shown) based on the value detected by the pressing force detector 70, and the pressure is controlled by the electropneumatic pressure control valve 81. The air supply is opened and closed by a pressing air solenoid valve 80. The pressing force of the piston 72 acts on the polisher 63 via the piston shaft 71, the pressing force detector 70, the motor drive spindle 66, the spindle 64, the chuck 65 and the polisher shaft 62.

The lower air chamber of the cylinder 73 is for raising and lowering the piston 72, and supplies air when the polisher 63 is separated from the workpiece 61 and the polishing process is stopped. The air supply is opened and closed by a lift air solenoid valve 85. The air used for these air pressure controls is supplied from the air source 83 to the working pressure by the original pressure control valve 82 and supplied as a secondary pressure.
A fishing line 74 coupled to the piston shaft 71 is guided by a pulley 75 and is tensioned by a weight hanging shaft 76 and a balance weight 78. The tension due to the weight of the weight hanging shaft 76 and the balance weight 78 is as follows: piston 72, piston shaft 71, pressure detector 70, motor drive spindle 66, air static pressure bearing 67, spindle 64, chuck 65, polisher shaft 62 and polisher 63. Is compensated by offsetting its own weight.

Further, since the weight hanging shaft 76 and the balance weight 78 are guided by the air static pressure bearing 77, even if the polishing head base 68 is inclined, the self-weight canceling compensation is maintained. As a result, the pressing force applied to the polisher 63 at the time of polishing becomes a pressing force based on the pressure of the pressure-controlled air applied in the upper air chamber of the cylinder 73.
Therefore, between the polisher 63 and the workpiece 61 by the rotation of the polisher 63 applied by the motor-driven spindle 66, the posture control operation of the workpiece 61, and the pressing force of the polisher 63 acting by the pressing force of the piston 72. A polishing motion and a polishing pressure necessary for polishing are applied.
The polishing process is performed by interposing polishing abrasive grains between the polisher 63 and the workpiece 61, or by attaching fixed abrasive grains to the polisher 63.
Japanese Patent Laid-Open No. 10-146748 Japanese Patent Laid-Open No. 10-230448

However, the polishing apparatus described in Patent Document 1 or 2 has the following problems.
That is, even if the pressure of the air introduced into the upper chamber of the cylinder 73 is precisely controlled by the electropneumatic pressure control valve 81, the pushing force of the polisher 63 that is actually generated due to the hysteresis and mechanical characteristics of the cylinder 73 and the piston 72. The pressure is not stable. That is, the air pressure introduced into the upper air chamber of the cylinder 73 cannot be stably controlled by the electropneumatic pressure control valve 81, the pressing force of the polisher 63 is not stable, or is introduced into the upper air chamber of the cylinder 73. There is a dead zone in the pressing force of the polisher 63 against the air pressure.

  For this reason, the polishing pressure cannot be maintained at a desired pressure, and the polishing conditions vary, so that the polishing result of the workpiece 61 also varies, resulting in non-uniform polishing results, for example, sagging on the processing surface of the workpiece 61 or insufficient polishing. Or an excessively polished part occurs, resulting in a defective shape. For example, there is an error of about 0.01 mm in the posture control of the workpiece 61, and if a change caused by this error is applied in the axial direction of the piston shaft 71, an error of about 10% may be generated in the pressing force of the polisher 63. Yes, even if it is detected by the pressing force detector 70 and fed back, the follow-up cannot be immediately performed due to the mechanical follow-up characteristics of the cylinder 73 or the dead zone of the electropneumatic pressure control valve 81.

  The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to maintain the polishing pressure as desired, to stabilize the polishing conditions, and to obtain a non-uniform polishing result such as sagging, insufficient polishing or polishing. An object of the present invention is to provide a polishing apparatus that suppresses the occurrence of excessive parts, facilitates control of polishing conditions for ensuring shape accuracy and shape accuracy, and processes a processed surface into a flat surface or a curved surface.

In order to achieve the above object, the present invention provides the following means.
The invention according to claim 1 is a polishing apparatus for polishing a processed surface of a workpiece by applying a polishing pressure to a polisher, and has an air chamber into which a fluid flows, and the fluid applied to the air chamber Pressure converting means for converting the fluid pressure into a pressing force that is the polishing pressure to the polisher, pressure control means for freely controlling the fluid pressure of the fluid to an arbitrary pressure, and pressure by the pressure control means Control of the fluid in any one or more of a conduit for introducing the controlled fluid into the pressure converting means, the air chamber of the pressure converting means, or a downstream conduit passing through the pressure converting means There is provided a polishing apparatus provided with an opening means for releasing a fluid into a space whose pressure is lower than the pressure.

In the polishing apparatus according to the present invention, the processed surface can be processed into an arbitrary three-dimensional surface such as a flat surface or a curved surface by polishing the processed surface of the workpiece with a polisher to which pressure is applied.
In particular, the source (source) of the polishing pressure applied to the polisher can be generated by pressure converting means for converting the pressure of the fluid into a pressing force, and this pressing force is controlled by controlling the pressure of the fluid by the pressure control means, It can be adjusted to a desired pressing force. In addition, since the release means is provided, not all the pressure of the fluid is consumed by the pressure conversion means, but a part of it is released to the low pressure part, so that the actual amount of fluid used is increased and the fluid is always consumed. Can be.

  In this way, the pressure control means can always be in an operating state by making the pressure-controlled fluid constantly consumed and adjusting the consumption to such an extent that the pressure can be controlled while consuming the fluid. Avoid mechanical hysteresis and dead band of pressure control means and pressure conversion means, or deterioration of followability, keep polishing pressure stable and desired, stabilize polishing conditions, and make non-homogeneous polishing results such as sagging and Generation of insufficiently polished or excessively polished parts can be suppressed, shape accuracy can be secured, and these controls can be realized with a simple configuration.

  According to a second aspect of the present invention, there is provided the polishing apparatus according to the first aspect, wherein the opening means arbitrarily gives resistance to the fluid flow passing through the opening means.

  In the polishing apparatus according to the present invention, when the fluid is allowed to escape to the low pressure portion, resistance is added to the flow of the fluid, and the fluid pressure on the pressure control means side from the opening means can be maintained in a state where the pressure can be controlled.

  According to the polishing apparatus of the present invention, the pressure control means is always in an operating state by making the pressure-controlled fluid constantly consumed and adjusting the consumption so that the pressure can be controlled while the fluid is consumed. It is possible to avoid mechanical hysteresis and dead zone of pressure control means and pressure conversion means, or deterioration of followability, keep the polishing pressure stable and desired, stabilize polishing conditions, and heterogeneous polishing As a result, for example, the occurrence of sagging, insufficient polishing or excessive polishing can be suppressed, and the shape accuracy can be ensured.

Hereinafter, a polishing apparatus according to a first embodiment of the present invention will be described with reference to FIG.
The polishing apparatus 1 of the present embodiment applies a polishing pressure to the polisher 3 on the processing surface W1 of a processing work (workpiece) W placed and fixed on the upper surface 2a of the work table 2 that can be freely controlled in three dimensions. By doing so, it is an apparatus for three-dimensional polishing.
The polishing apparatus 1 includes the work table 2, the polisher 3 disposed opposite to the upper surface 2a of the work table 2, and an air chamber into which fluid flows, that is, an upper air chamber 5 and a lower air chamber 6. Then, the fluid pressure of the fluid applied to both the air chambers 5 and 6 is converted into a pressing force which becomes the polishing pressure to the polisher 3, that is, the pressure difference between the fluid pressures applied to both the air chambers 5 and 6 is pressed. An actuator (pressure converting means) 7 for converting to a pressure, an electropneumatic pressure control valve (pressure control means) 8 for freely controlling the fluid pressure of the fluid to an arbitrary pressure, and pressure control by the electropneumatic pressure control valve 8 Pressure in the one or more of the pipe line 9 for introducing the fluid into the actuator 7, both the air chambers 5 and 6 of the actuator 7, or the downstream pipe line that has passed through the actuator 7. Open fluid in low space Adjusting throttle valve and a (opening means) 10.
Moreover, in this embodiment, the adjustment throttle valve 10 is provided in the pipe line 9, and arbitrarily gives resistance to the flow of the fluid passing through the adjustment throttle valve 10.

The work table 2 can be controlled in three-dimensional attitude based on machining data by a control device (not shown) and an attitude driving device, and a workpiece W having a free-form machining surface W1 is placed on the upper surface 2a. Fix it.
A spherical polisher 3 having a polisher shaft 11 is fastened and fixed to a spindle shaft 12 by a collet-shaped chuck 13, and the spindle shaft 12 can be rotated by a motor-driven spindle 14.

The motor drive spindle 14 is integrally fixed to an air static pressure bearing 15 having an extremely low sliding resistance, and the air static pressure bearing 15 is inserted and guided through a guide shaft 17 fixed to the polishing head base 16.
The motor drive spindle 14 is fixed to a piston shaft 18, and a piston 19 is integrally provided on the piston shaft 18. The piston 19 forms the upper air chamber 5 and the lower air chamber 6 of the cylinder, and receives the vertical pressure by the piston 19. The piston 19 and the cylinder 20 constitute the actuator 7, and the piston 19 and the cylinder 20 of the actuator 7 have a static pressure bearing structure and have a minimum sliding resistance.

The upper end of the piston shaft 18 is coupled to a fishing line 21 of a thread excellent in tension, and the fishing line 21 is guided by a pulley 22 rotatably provided on the polishing head base 16, and its working direction is folded back 180 °, and the other end Is coupled to the upper end of the weight shaft 23.
The weight hanging shaft 23 is inserted into an air static pressure bearing 24 with extremely low sliding resistance fixed to the polishing head base 16 and can be moved up and down with extremely low sliding resistance. A balance weight 25 is screwed and fixed to the lower end screw portion of the weight hanging shaft 23.

The upper air chamber 5 of the cylinder 20 has a pressing port 26 for introducing air, and is connected to a pressing air solenoid valve 27 for controlling opening and closing of the air through the pipe line 9. Further, the pressure air electromagnetic valve 27 is connected to the electro-pneumatic pressure control valve 8 and further includes a pneumatic circuit so as to be connected to the air source 29 via the original pressure control valve 28. The electropneumatic pressure control valve 8 is controlled by a control device (not shown) and can freely control the air pressure.
Further, the lower air chamber 6 of the cylinder 20 has an elevating port 30 for introducing air, and is connected to an elevating air electromagnetic valve 31 for controlling the opening and closing of the air through the pipeline 9. Further, the lift air solenoid valve 31 is connected to the air source 29 via the original pressure control valve 28.
Further, the adjusting throttle valve 10 is branched and provided in the middle of the pipeline 9 between the pressing air electromagnetic valve 27 and the pressing port 26.

A case where the processing surface W1 of the workpiece W is polished by the polishing apparatus 1 configured as described above will be described.
First, the work table 2 is maintained by the posture drive device and the control device (not shown) while maintaining the posture of the workpiece W so that the workpiece W always abuts the polisher 3 in the normal L direction based on the machining data, and It is controlled to scan the polishing site.
The polisher shaft 11 of the polisher 3 is fastened and fixed to the spindle shaft 12 by the chuck 13, and transmits the motion of the spindle shaft 12 rotated by the motor drive spindle 14 to the polisher 3. By the rotation of the polisher 3 and the posture control operation of the workpiece W, a polishing motion is relatively performed and polishing is performed. At this time, since the motor drive spindle 14 is guided along the guide shaft 17 via the air hydrostatic bearing 15, the motor drive spindle 14 moves up and down with a very slight sliding resistance. The pressure of the piston 19 is generated by air supplied under pressure control to the upper air chamber 5 of the cylinder 20.

The pressure of the air supplied to the upper air chamber 5 is controlled by an electropneumatic pressure control valve 8 that is controlled by a control device (not shown). The air supply is opened and closed by a pressing air solenoid valve 27. The pressing force of the piston 19 acts on the polisher 3 via the piston shaft 18, the motor drive spindle 14, the spindle shaft 12, the chuck 13, and the polisher shaft 11.
The lower air chamber 6 of the cylinder 20 is for raising and lowering the piston 19 and supplies air when the polisher 3 is separated from the workpiece W and the polishing process is stopped. The air supply is opened and closed by a lift air solenoid valve 31. The air supplied to these air pressure controls is supplied to the working pressure from the air source 29 by the original pressure control valve 28 and supplied as a secondary pressure.

A fishing line 21 coupled to the piston shaft 18 is guided by a pulley 22 and is tensioned by a weight hanging shaft 23 and a balance weight 25. The tension due to the weights of the weighting shaft 23 and the balance weight 25 cancels and compensates for the weights of the piston 19 and the piston shaft 18, the motor drive spindle 14, the air static pressure bearing 15, the spindle shaft 12, the chuck 13, the polisher shaft 11 and the polisher 3. is doing.
Further, since the weight hanging shaft 23 and the balance weight 25 are guided by the air static pressure bearing 24, even when the polishing head base 16 is inclined, the self-weight canceling compensation is maintained.

  As a result, the pressing force applied to the polisher 3 at the time of polishing is the pressing force by the pressure-controlled air pressure applied in the upper air chamber 5 of the cylinder 20 and the weight of the apparatus is offset. The pressing force can also be controlled. Therefore, the polishing between the polisher 3 and the workpiece W is polished by the rotation of the polisher 3 applied by the motor-driven spindle 14, the movement of the workpiece W, and the pressing force of the polisher 3 acting by the pressing force of the piston 19. Polishing motion and polishing pressure required for processing are applied.

  Polishing is performed by interposing polishing abrasive grains between the polisher 3 and the workpiece W. When the pressure air solenoid valve 27 is open, the regulating throttle valve 10 releases the pressure-controlled air between the electropneumatic pressure control valve 8 and the upper air chamber 5 of the cylinder 20 to the atmosphere while resisting the flow rate with the throttle. is doing. Therefore, the air from the electropneumatic pressure control valve 8 to the upper air chamber 5 of the cylinder 20 continuously consumes air while maintaining the pressure controlled by the electropneumatic pressure control valve 8 including the inside of the pipe line 9, and In order to compensate for the exhaustion, the electropneumatic pressure control valve 8 always supplies pressure-controlled air. At this time, the static air pressure in the pipe line 9 to the upper air chamber 5 of the cylinder 20 and the electropneumatic pressure control valve 8 is equalized, and the air supply state is always maintained continuously.

  As described above, according to the polishing apparatus 1 of the present embodiment, since the electropneumatic pressure control valve 8 is always in an operating state and there is no resting state, the cylinder can be used regardless of the hysteresis or dead zone of the electropneumatic pressure control valve 8. The air pressure supplied to the 20 upper air chambers 5 is stable. Further, non-following and dead zones of the pressing force of the piston 19 due to mechanical characteristics caused by minute waviness of the workpiece W can be reduced. As a result, polishing conditions are stabilized, excessive polishing does not occur, and polishing that maintains uniform shape accuracy can be performed.

Next, a second embodiment of the polishing apparatus 40 according to the present invention will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
The difference between the second embodiment and the first embodiment is that the adjustment throttle valve 10 is employed as the opening means in the first embodiment, whereas the open / close check valve 41 is employed as the opening means in the second embodiment. It is a point to do.

That is, as shown in FIG. 2, the polishing apparatus 40 of the present embodiment processes a free-form surface on a work table 2 that can be controlled in a three-dimensional manner based on processing data by a control device and a drive device (not shown). The workpiece W having the surface W1 is placed and fixed.
A spherical polisher 3 having a polisher shaft 11 is fastened and fixed to a spindle shaft 12 by a collet-shaped chuck 13, and the spindle shaft 12 can be rotated by a motor-driven spindle 14.

The motor drive spindle 14 is integrally fixed to an air static pressure bearing 15 with extremely low sliding resistance, and the air static pressure bearing 15 is inserted and guided through a guide shaft 17 fixed to the polishing head base 16.
The motor drive spindle 14 is fixed to a piston shaft 18, and a piston 19 is integrally provided on the piston shaft 18. The piston 19 includes an upper air chamber 5 and a lower air chamber 6 of the cylinder 20, and the piston 19 receives vertical pressure. Further, the piston 19 and the cylinder 20 have a static pressure bearing structure and have minimal sliding resistance.

The upper end of the piston shaft 18 is coupled to a fishing line 21 that is excellent in tension. The fishing line 21 is guided by a pulley 22 that is rotatably provided on the polishing head base 16 and is turned back by 180 °, and the other end is a weight. It is coupled to the upper end of the hanging shaft 23.
The weight hanging shaft 23 is inserted into an air static pressure bearing 24 with extremely low sliding resistance fixed to the polishing head base 16 and can be moved up and down with extremely low sliding resistance. A balance weight 25 is screwed and fixed to the lower end screw portion of the weight hanging shaft 23.

The upper air chamber 5 of the cylinder 20 has a pressing port 26 for introducing air, and is connected to a pressing air solenoid valve 27 for controlling opening and closing of the air through the pipe line 9. Further, the pressure air electromagnetic valve 27 is connected to the electropneumatic pressure control valve 8 and further has a pneumatic circuit so as to be connected to the air source 29 via the original pressure control valve 28. The electropneumatic pressure control valve 8 is controlled by a control device (not shown) and can freely control the air pressure.
Further, the lower elevating port 30 of the cylinder 20 has an elevating port 30 for introducing air, and is connected to an elevating air electromagnetic valve 31 that controls the opening and closing of the air through the pipe 9. Further, the lift air solenoid valve 31 is connected to the air source 29 via the original pressure control valve 28. Further, the open / close check valve 41 is branched in the middle of the pressing air electromagnetic valve 27 and the pipe 9 of the pressing port 26.

A case where the processing surface W1 of the workpiece W is polished by the polishing apparatus 40 configured as described above will be described.
First, the work table 2 is maintained by the posture driving device and the control device (not shown) while maintaining the posture of the workpiece W so that the workpiece W always abuts the polisher 3 in the normal L direction based on the machining data. Operate to scan the polishing site.
The polisher shaft 11 of the polisher 3 is fastened and fixed to the spindle shaft 12 by the chuck 13, and transmits the motion of the spindle shaft 12 rotated by the motor drive spindle 14 to the polisher 3. The rotation of the polisher 3 and the operation of the workpiece W are relatively a polishing motion. Since the motor drive spindle 14 is guided along the guide shaft 17 via the air hydrostatic bearing 15, it moves up and down with a very slight sliding resistance. The pressure of the piston 19 is generated by air supplied under pressure control to the upper air chamber 5 of the cylinder 20.

The pressure of the air supplied to the upper air chamber 5 is controlled by an electropneumatic pressure control valve 8 that is controlled by a control device (not shown). The air supply is opened and closed by a pressing air solenoid valve 27. The pressing force of the piston 19 acts on the polisher 3 via the piston shaft 18, the motor drive spindle 14, the spindle shaft 12, the chuck 13 and the polisher shaft 11.
The lower air chamber 6 of the cylinder 20 is for raising and lowering the piston 19 and supplies air when the polisher 3 is separated from the workpiece W and the polishing process is stopped. The air supply is opened and closed by a lift air solenoid valve 31. The air supplied to these air pressure controls is supplied to the working pressure from the air source 29 by the original pressure control valve 28 and supplied as a secondary pressure.

  A fishing line 21 coupled to the piston shaft 18 is guided by a pulley 22 and is tensioned by a weight hanging shaft 23 and a balance weight 25. The tension due to the weight of the weighting shaft 23 and the balance weight 25 compensates for the weight of the piston 19, the piston shaft 18, the motor drive spindle 14, the air hydrostatic bearing 15, the spindle shaft 12, the chuck 13, the polisher shaft 11 and the polisher 3. is doing.

  Further, since the weight hanging shaft 23 and the balance weight 25 are guided by the air static pressure bearing 24, even if the polishing head base 16 is inclined, the self-weight canceling guarantee is maintained. As a result, the pressing force applied to the polisher 3 at the time of polishing becomes the pressing force by the pressure-controlled air pressure applied in the upper air chamber 5 of the cylinder 20 and the weight of the apparatus is offset, so that a minute pressing force is applied. The pressure can also be controlled. Therefore, the polishing between the polisher 3 and the workpiece W is polished by the rotation of the polisher 3 applied by the motor-driven spindle 14, the movement of the workpiece W, and the pressing force of the polisher 3 acting by the pressing force of the piston 19. Polishing motion and polishing pressure required for processing are applied. Polishing is performed by interposing polishing abrasive grains between the polisher 3 and the workpiece W.

  When the pressure air solenoid valve 27 is open, the open / close check valve 41 intermittently switches the pressure-controlled air between the electropneumatic pressure control valve 8 and the upper air chamber 5 of the cylinder 20 to the flow rate by instantaneous opening and closing of the valve. Open to the atmosphere while applying resistance. Therefore, the air in the upper air chamber 5 of the cylinder 20 from the electropneumatic pressure control valve 8 is instantaneously and intermittently consumed while maintaining the pressure controlled by the electropneumatic pressure control valve 8 including the inside of the conduit 9. In addition, the electropneumatic pressure control valve 8 supplies pressure-controlled air to compensate for wear. At this time, the static air pressure in the pipe line 9 to the upper air chamber 5 of the cylinder 20 and the electropneumatic pressure control valve 8 becomes equal. The opening / closing of the open / close check valve 41 is instantaneously intermittent open / close, and the air is released from the open / close check valve 41 while performing small air pulsations.

As described above, according to the polishing apparatus 40 of the present embodiment, since the electropneumatic pressure control valve 8 is always in an operating state and there is no resting state, the cylinder 20 regardless of the hysteresis or dead zone of the electropneumatic pressure control valve 8. The air pressure supplied to the upper air chamber 5 is stable. Further, non-following and dead zones of the pressing force of the piston 19 due to mechanical characteristics caused by minute waviness of the workpiece W can be reduced.
In particular, when the open / close check valve 41 is instantaneously opened and closed, it becomes a random noise that moderately accelerates operation in a region where the electro-pneumatic pressure control valve 8 to the cylinder 20 slide resistance and the electro-pneumatic pressure control valve 8 are insensitive. There is an effect to obtain a pressing function. As a result, the polishing conditions are stabilized, the polishing results do not vary, and uniform polishing results can be obtained.
Therefore, sagging due to the part, insufficient polishing, and excessive polishing do not occur, and polishing can be performed while maintaining good shape accuracy. In this way, it is possible to easily control the polishing conditions for ensuring the shape accuracy and the shape accuracy. The air pulsation is minute and has no effect on polishing when it is repeated instantaneously.

Next, a third embodiment of the polishing apparatus 50 according to the present invention will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
The difference between the third embodiment and the first embodiment is that, in the first embodiment, an adjusting throttle valve 10 provided in the conduit 9 between the electropneumatic pressure control valve 8 and the pressing port 26 is employed as the opening means. On the other hand, in the third embodiment, the adjustment throttle valve 51 provided in the downstream pipe line that has passed through the cylinder 20 is employed as the opening means.

That is, as shown in FIG. 3, the polishing apparatus 50 of the present embodiment processes a free-form surface on a work table 2 that can be freely controlled in three-dimensional orientation based on processing data by a control device (not shown) and a drive device. The workpiece W having the surface W1 is placed and fixed.
A spherical polisher 3 having a polisher shaft 11 is fastened and fixed to a spindle shaft 12 by a collet-shaped chuck 13, and the spindle shaft 12 can be rotated by a motor-driven spindle 14.

  The motor drive spindle 14 is integrally fixed to an air static pressure bearing 15 with extremely low sliding resistance, and the air static pressure bearing 15 is inserted and guided through a guide shaft 17 fixed to the polishing head base 16. The motor drive spindle 14 is fixed to a piston shaft 18, and a piston 19 is integrally provided on the piston shaft 18. The piston 19 has an upper air chamber 5 and a lower air chamber 6 of the cylinder 20, and the piston 19 receives vertical pressure. Further, the piston 19 and the cylinder 20 have a static pressure bearing structure and have minimal sliding resistance.

The upper end of the piston shaft 18 is coupled to a fishing line 21 of a thread excellent in tension, and the fishing line 21 is guided by a pulley 22 rotatably provided on the polishing head base 16, and its working direction is folded back 180 °, and the other end Is coupled to the upper end of the weight shaft 23.
The weight hanging shaft 23 is inserted into an air static pressure bearing 24 with extremely low sliding resistance fixed to the polishing head base 16 and can be moved up and down with extremely low sliding resistance. A balance weight 25 is screwed and fixed to the lower end screw portion of the weight hanging shaft 23.

The upper air chamber 5 of the cylinder 20 has a pressing port 26 for introducing air, and is connected to a pressing air solenoid valve 27 for controlling opening and closing of the air through the pipe line 9. Further, the pressure air electromagnetic valve 27 is connected to the electropneumatic pressure control valve 8 and further has a pneumatic circuit so as to be connected to the air source 29 via the original pressure control valve 28.
The electropneumatic pressure control valve 8 is controlled by a control device (not shown) and can freely control the air pressure. The lower air chamber 6 of the cylinder 20 has an elevating port 30 for introducing air, and is connected to an elevating air electromagnetic valve 31 that controls the opening and closing of the air through the conduit 9. Further, the lift air solenoid valve 31 is connected to the air source 29 via the original pressure control valve 28.

  The adjustment throttle valve 51 is provided in the upper air chamber 5 of the cylinder 20. That is, on the side of the upper air chamber 5 of the actuator 7 composed of the piston 19 and the cylinder 20 for converting the fluid pressure into the pressing force, a downstream pipe (not shown) for the fluid passing through the upper air chamber 5 is provided. An adjustment throttle valve 51 is provided in the downstream pipe line.

A case where the processing surface W1 of the workpiece W is polished by the polishing apparatus 50 configured as described above will be described.
First, the work table 2 is maintained by the posture driving device and the control device (not shown) while maintaining the posture of the workpiece W so that the workpiece W always abuts the polisher 3 in the normal L direction based on the machining data. Operate to scan the polishing site.
The polisher shaft 11 of the polisher 3 is fastened and fixed to the spindle shaft 12 by the chuck 13 and transmits the movement of the spindle shaft 12 rotated by the motor drive spindle 14 to the polisher 3. The rotation of the polisher 3 and the operation of the workpiece W are relatively a polishing motion.

  Since the motor drive spindle 14 is guided along the guide shaft 17 via the air hydrostatic bearing 15, it moves up and down with a very slight sliding resistance. The pressure of the piston 19 is generated by air supplied under pressure control to the upper air chamber 5 of the cylinder 20. The pressure of the air supplied to the upper air chamber 5 is controlled by an electropneumatic pressure control valve 8 that is controlled by a control device (not shown). The air supply is opened and closed by a pressing air solenoid valve 27. The pressing force of the piston 19 acts on the polisher 3 via the piston shaft 18, the motor drive spindle 14, the spindle shaft 12, the chuck 13 and the polisher shaft 11.

  The lower air chamber 6 of the cylinder 20 is for raising and lowering the piston 19 and supplies air when the polisher 3 is separated from the workpiece W and the polishing process is stopped. The air supply is opened and closed by a lift air solenoid valve 31. The air supplied to these air pressure controls is supplied to the working pressure from the air source 29 by the original pressure control valve 28 and supplied as a secondary pressure.

  A fishing line 21 coupled to the piston shaft 18 is guided by a pulley 22 and is tensioned by a weight hanging shaft 23 and a balance weight 25. The tension due to the weights of the weighting shaft 23 and the balance weight 25 cancels and compensates for the weights of the piston 19, the piston shaft 18, the motor drive spindle 14, the air hydrostatic bearing 15, the spindle shaft 12, the chuck 13, the polisher shaft 11, and the polisher 3. is doing.

Further, since the weight hanging shaft 23 and the balance weight 25 are guided by the air static pressure bearing 24, even when the polishing head base 16 is inclined, the self-weight canceling compensation is maintained. As a result, the pressing force applied to the polisher 3 at the time of polishing becomes the pressing force by the pressure-controlled air pressure applied in the upper air chamber 5 of the cylinder 20 and the weight of the apparatus is offset. The pressure can also be controlled.
Therefore, the polishing between the polisher 3 and the workpiece W is polished by the rotation of the polisher 3 applied by the motor-driven spindle 14, the movement of the workpiece W, and the pressing force of the polisher 3 acting by the pressing force of the piston 19. A polishing motion and a polishing pressure necessary for processing are applied. Polishing is performed by interposing polishing abrasive grains between the polisher 3 and the workpiece W.

  The adjustment throttle valve 51 provided in the downstream pipe line on the side of the cylinder 20 in the actuator 7 controls the pressure from the electropneumatic pressure control valve 8 to the upper air chamber 5 of the cylinder 20 when the pressing air solenoid valve 27 is open. The supplied air is released to the atmosphere while applying a resistance to the flow rate with a throttle. Therefore, the air in the upper air chamber 5 of the cylinder 20 is constantly exhausted while maintaining the pressure controlled by the electropneumatic pressure control valve 8, and the electropneumatic pressure control valve 8 is always in order to compensate for the exhaustion. Always supply pressure-controlled air.

As described above, according to the polishing apparatus 50 of the present embodiment, since the electropneumatic pressure control valve 8 is always in an operating state and there is no resting state, the cylinder 20 regardless of the hysteresis or dead zone of the electropneumatic pressure control valve 8. The air pressure supplied to the upper air chamber 5 is stable. Further, non-following and dead zones of the pressing force of the piston 19 due to mechanical characteristics caused by minute waviness of the workpiece W can be reduced.
Furthermore, in this embodiment, since the adjustment throttle valve 51 is provided directly in the upper air chamber 5 of the cylinder 20, the response to the pressing force is good. As a result, the polishing conditions are stabilized, the polishing results do not vary, and uniform polishing results can be obtained. Therefore, sagging due to the part, insufficient polishing, and excessive polishing do not occur, and polishing can be performed while maintaining good shape accuracy. In this way, it is possible to easily control the polishing conditions for ensuring the shape accuracy and the shape accuracy.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in each of the above embodiments, the regulating throttle valve 10, the on-off check valve 41, and the regulating throttle valve 51 are used as the opening means that opens the fluid to a space whose pressure is lower than the control pressure of the fluid. Using a rotatable disk in which a plurality of different orifices are concentrically formed and rotating around the rotation center axis of the disk, one is selected from the plurality of orifices, and the selected orifice is passed through the selected orifice. The fluid may be released.

It is a lineblock diagram of a 1st embodiment of a polish device concerning the present invention. It is a block diagram of 2nd Embodiment of the grinding | polishing apparatus which concerns on this invention. It is a block diagram of 3rd Embodiment of the grinding | polishing apparatus which concerns on this invention. It is a block diagram which shows an example of the conventional grinding | polishing apparatus.

Explanation of symbols

W Workpiece (Workpiece)
W1 Processed surface 1, 40, 50 Polishing device 2 Work table 3 Polisher 7 Actuator (pressure conversion means)
8 Electro-pneumatic pressure control valve (pressure control means)
9 Pipe line 10, 51 Adjusting throttle valve (opening means)
DESCRIPTION OF SYMBOLS 11 Polisher shaft 12 Spindle shaft 13 Chuck 14 Motor drive spindle 15, 24 Air static pressure bearing 16 Polishing head base 17 Guide shaft 18 Piston shaft 19 Piston 20 Cylinder 21 Fishing line 22 Pulley 23 Weight hanging shaft 25 Balance weight 26 Press port 27 Press Air solenoid valve 28 original pressure control valve
29 Air source 30 Elevating port 31 Elevating air solenoid valve 41 Open / close check valve (opening means)

Claims (2)

A polishing apparatus for polishing a processed surface of a workpiece by applying a polishing pressure to a polisher,
A pressure conversion means for converting the fluid pressure of the fluid applied to the air chamber into a pressing force which is the polishing pressure to the polisher, and has an air chamber into which the fluid flows.
Pressure control means for freely controlling the fluid pressure of the fluid to an arbitrary pressure;
Any one or more of a conduit that introduces the fluid whose pressure is controlled by the pressure controller into the pressure converter, the air chamber of the pressure converter, or a downstream pipe that has passed through the pressure converter And an opening means for releasing the fluid into a space whose pressure is lower than the control pressure of the fluid. The polishing apparatus according to claim 1, wherein
The polishing apparatus according to claim 1, wherein the opening means arbitrarily gives resistance to the fluid flow passing through the opening means.

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