JPS6033601B2 - ultra precision lathe - Google Patents

Description

Detailed Description of the Invention The present invention has a surface roughness of 0.02-Rz and a waviness of 0.05.
The present invention relates to an ultra-precision lathe that enables ultra-precision machining on the order of '' side.

For machine tools that perform ultra-precision machining, the usual method is to accurately transfer the precision of the machine to the workpiece.

For example, when processing the surface of a computer memory disk to increase its storage capacity, surface roughness and waviness become a particular problem. Considering that it will be transferred to the surface of the disk, it must not only satisfy static accuracy but also dynamic accuracy during processing.

That is, all the moving bodies of a machine must have excellent motion functions, and the drive source that provides the driving force for the moving bodies must also be taken into consideration so as not to adversely affect the dynamic accuracy of the machine. The machine must also be constructed so that it is not affected by external vibrations, such as transmission from other vibration sources via the ground. None of the existing machine tools could meet these demands.

The present invention provides an ultra-precision lathe that can achieve the above objects, and has the following features.

01 Improving the motion function of the moving body The most important moving bodies during machining are the spindle that holds and rotates the workpiece, and the carriage that holds the cutter and reciprocates in a direction perpendicular to the center of the bag.

What governs the motion functions of these spindles and carriages are:
They are a bearing that guides and supports the radial direction and thrust direction of the main shaft, and a guide section that guides and supports the sliding surface of the carriage. The present invention uses a pressure bearing for the bearing of the main shaft and the guide portion of the carriage, thereby improving the motion function of the moving body. {2) Drive method for the main shaft and carriage The motors that are the drive sources for the main shaft and carriage are both supported by a pet that is placed separately from the pet that supports the main shaft and carriage, and the vibrations of the motor are This prevents it from being transmitted to the main unit.

Further, a flexible coupling is interposed between the motor shaft and a pulley shaft supporting the belt so that rotational vibration of the motor shaft is not transmitted to the belt connected to the main shaft.

Furthermore, a measure of the transmission of driving force between the motor shaft and the carriage,
In order to reduce the occurrence of vibration, steel wire is used, and the flexibility of this steel wire is applied to eliminate disturbances in the drive force transmission. Glue Elimination of External Vibrations In order to eliminate external vibrations from being transmitted to the main shaft, carriage, etc. through the pet that supports them, the pet has a special structure.

That is, the pet is formed using an anchor machine, and this lathe is supported by an air cushion device. Anchor boards have higher internal structural damping than steel, etc., so they are resistant to external vibrations. Cast and iron box-shaped pets have complex natural vibrations and natural vibration modes, but anchor boards have simple vibrations. In most cases, it is sufficient to consider the vibrations caused by the springs of the legs that support the anchor board. Furthermore, even if vibration occurs in the anchor machine due to the lathe and the springs in the legs, the main shaft and carriage supported by this anchor machine will vibrate as one with the anchor machine, causing the darkness between the workpiece and the cutter. Since no relative displacement occurs, there is no problem in machining the workpiece. Furthermore, the legs of the anchor board are equipped with an air cushion device, which is designed to eliminate external vibrations. As described above, the present invention is designed to improve dynamic tactility in each part.

In Figure 1, 1 is an anchor board, and the top surface has a headstock 2,
The sliding guide device 3 is fixed, and a plurality of cylindrical air cushions 4 made of rubber and filled with compressed air are fixed to the legs.

As shown in FIG. 2, the headstock 2 rotatably supports a vacuum chuck 5 that holds a workpiece (not shown) by suction and a main shaft 7 that holds a pulley 6 at both ends, and also supports the main shaft 7 in the radial direction of the main shaft 7. and static pressure bearings 8a, 8b, and 8c that respectively hold both side surfaces, that is, the thrust direction of the main shaft 7, are fixed so that the large-diameter flange portion 7' of the main shaft 7 is inserted. The sliding guide device 3 has a sliding surface perpendicular to the axial center of the main shaft 7, and a reciprocating table 9 that moves along the sliding surface is connected via a hydrostatic bearing 10 as shown in FIG. I support it. This reciprocating carriage 9 supports a tool rest 12 so as to be slidable in the centroidal direction of the main shaft 7 by a drive motor 11, and a cutter 13 is fixed to this tool rest 12. Reference numeral 14 denotes a main shaft drive motor, which is fixed on a base 15 disposed 8U from the anchor board 1 as shown in FIG. is connected to.

This pulley shaft 18 is connected to the pulley 6 of the main shaft 7 via a flat belt 19. Reference numeral 20 is a tension adjustment pulley, which is rotatably supported by a bracket 21 fixed to the base 15 via an arm 22, and is configured to apply tension to the flat belt 19 and suppress vibration of the flat belt 19. There is.

23 is fixed on a base 24 arranged separately from the anchor board 1 by means of a reciprocating carriage drive motor, and its end portion is connected to a wheel 26 via a speed reducer 25.

This foil 26 has a steel wire 27 connected at one end to one end of the carriage 11. Reference numeral 28 is a steel wire, one end of which is connected to the other end of the carriage 9, and the other end of which is connected to a balance weight 29 in the vertical direction.

The balance weight 29 uses its own weight to push and pull the carriage 9 toward the balance weight 29 to eliminate the backlash of the gear in the reducer 25. Since the steel wire 27 has flexibility in the tension direction and in the direction perpendicular thereto, it prevents disturbances in the transmission of the driving force from the foil 26 to the carriage 11. With the above configuration, when the main shaft drive motor 14 is driven after the workpiece is held by vacuum suction on the vacuum chuck 5, the main shaft 7 is rotated via the flat belt 19, thereby rotating the workpiece.

In this case, the main shaft 7 is held with high precision by hydrostatic air bearings 8a, 8b, and 8c, and the base 15 of the main shaft drive motor 14 is arranged separately from the anchor board 1, and the two tension adjustment pulleys are connected to the flat belt. Since the vibration of 19 is suppressed, the rotation accuracy of the workpiece is maintained at high accuracy. On the other hand, when the carriage drive motor 23 is driven, the wheel 26 is rotated via the reducer 25, and the carriage 11 is moved along the sliding guide device 3 via the steel wire 27 in a direction perpendicular to the axis 0 of the main shaft 7. The drive motor 11 drives the cutter 13 to move in the center direction of the main shaft 7 via the tool post 12, and the cutter 13 processes the workpiece. In this case, the carriage drive motor 23 is fixed on a base 24 separate from the anchor board 1, and a steel wire 27 prevents vibrations from the foil 26 from being transmitted to the carriage 9. Since the blade 9 is held in the sliding guide device 3 with high precision by the hydrostatic air bearing 10, the cutter 13 can machine the workpiece with high precision.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the entire ultra-precision lathe according to the present invention;
FIG. 2 is a sectional view showing the headstock, FIG. 3 is a sectional view showing the headstock driving section, and FIG. 4 is a sectional view showing the reciprocating guide section of the sliding guide device. 1... Lathe, 2... Headstock, 3... Sliding guide device, 4... Air action, 5... Vacuum chuck, 7... King shaft,
8a, 8b, 8c... Static pressure air axis length, 9... Carriage table, 1
0... Static pressure air bearing, 11... Drive motor, 12...
Turret, 13...Cuttle, 14...Main shaft drive motor, 15
...Base, 16...Flexible cutlet spring, 17...Pulley shaft, 19...Flat belt, 20...Tension adjustment pulley, 2
3... Carriage drive motor, 24... Base, 25...
...Feed reducer, 16...Foil, 27, 28...Steel wire, 29...Balance way. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Air bearings are provided in the support part of the spindle that supports the workpiece and rotates, and in the sliding guide part of the carriage that supports the cutting tool and is perpendicular to the axis of the spindle, and drives the spindle and the carriage, respectively. A base supporting the motor is provided independently from a base supporting the main shaft and the carriage, the base supporting the main shaft and the carriage is formed of an anchor board, and this anchor board is supported by an air action device. An ultra-precision lathe characterized by being configured as follows.