JPS6035560Y2 - Spindle rotation mechanism in turning machine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a spindle rotation mechanism that prevents vibrations generated from a rotary motor in a cutting machine that requires ultra-precision machining.

Generally, when a spindle with a fixed workpiece is rotated at high speed in a lathe or the like, vibrations generated from a spindle power source such as a motor or a belt may be transmitted to the workpiece and cause it to vibrate slightly.

The width of this vibration varies in size, and it is usually within the error range that affects cutting accuracy, so it is often not a problem, but as the workpiece becomes smaller and cutting accuracy within a few microns is required. In the case of ultra-precision processing machines, the vibration generated by the motor greatly affects the rotational accuracy of the spindle, negatively affecting the roundness of the workpiece or the accuracy of the finished surface, and promotes uneven wear of the cutting tool tip made of diamond, etc. This results in the disadvantage of shortening the lifespan.

The present invention was developed in view of the above, and aims to obtain a spindle rotation mechanism that is useful when applied to ultra-precision processing machines, and is mainly affected by vibrations caused by rotational power sources such as motors when cutting workpieces. The main objective is to obtain a spindle rotation mechanism for a cutting machine that eliminates all of the above.

FIG. 1 is a perspective view of main parts showing a first embodiment of the present invention,
FIG. 2 is a side sectional view of the same.

Reference numeral 1 denotes a motor as a rotational power source, and in this example, an electric motor is used.

The base 2 of the motor 1 is fixed to a flange 4 by a tightening bolt 3, and the flange 4 is formed integrally with a moving table 5.

The movable table 5 is connected to a rond (not shown) of the fluid pressure cylinder 6, and is capable of sliding over a plurality of guide surfaces 7.

One end side of the fluid pressure cylinder 6 is coupled and fixed to one end side of the base 8.

A rotating shaft 9 protrudes from the output side of the motor 1, and a key 10
A cylindrical flange 11 that connects and rotates by the cylindrical flange 11 and an annular groove 13 cut into a convex connecting member 12 with one end having a conical shape.
The spring 14 is pressurized in between and is fitted.

Furthermore, a threaded portion 9' is provided at the tip of the rotating shaft 9, and a stopper 15 is screwed into the stopper 15, and the stopper 15 is fixed by a set screw 15', and the connecting member 12 is deviated in the axial direction by the pressing force of the spring 14. It prevents

On the other hand, a concave connecting member 16 disposed opposite to the convex connecting member 12 is provided, and a friction pad 17 is interposed between the concave connecting member 16 and the convex connecting member 12. It is pasted on the surface 12'.

The concave connecting member 16 is fitted into the rear end portion 18 of the main shaft 20,
It is fixed by a pin 19 and rotates integrally.

In FIG. 2, the convex connecting member 12 and the concave connecting member 16 are connected via the friction pad 17 by the pressing force of the spring 14, and function to transmit rotational force by friction.

Further, the axes of the rotating shaft 9 and the main shaft 20 are arranged to coincide with each other.

Reference numeral 21 denotes a flywheel connected to the main shaft 20 by a connecting piece 22. The flywheel 21 is fixed to the main shaft 20 by a nut 24 screwed into the threaded portion 23 of the main shaft 20 so that its position relative to the main shaft 20 is immovable. Rotate in conjunction.

The main shaft 20 has an aerostatic pressure bearing mechanism 8 at the upper part of the base 8.
′.

That is, a flange 25 is provided protruding approximately at the center of the main shaft 20, and a feed passage 27 piped from an air pump 26 is inserted through the base and the aerostatic bearing mechanism 8' to provide a radial direction relative to the main shaft 20. The pockets 28 and 28 are connected to pockets 29 and 29 in the thrust direction from both sides of the flange 25, and compressed air is blown out from each pocket to support the main shaft 20 in a floating manner.

Each component that rotates integrally with the main shaft 20 has a configuration that takes into consideration balanced precision.

30 is a rotation sensor provided inside the base 8 and close to the flywheel 21.

The operation mode of the first embodiment is as follows.

A chuck mechanism (not shown) is attached to the tip 20' of the main shaft 20, and firmly grips the workpiece.

A cutting tool is made to protrude from a turret mounted in opposition to the workpiece, and the tip of the cutting tool is brought close to the workpiece.

Most of the workpieces subjected to ultra-precision machining are made of light alloys such as aluminum, and light cutting work is mainly performed using a diamond cutting tool, so the rotational torque on the main shaft 20 side can be relatively small.

When the fluid pressure cylinder 6 is driven in the direction of arrow A, the concave connecting member 16 connected to the main shaft 20 side and the convex connecting member 12 biased by the spring 14 from the flange 11 provided on the motor 1 side connect the friction pad 17. It is strongly pressed toward the main shaft 20 in the axial direction, so that a friction clutch is connected by spring pressure.

When the motor 1 is driven to rotate as described above, the rotation of the rotating shaft 9 is directly transmitted to the main shaft 20 via the convex connecting member 12, the friction pad 17, and the concave connecting member 16.
drive the rotation.

Therefore, the flywheel 21 also rotates in synchronization with the main shaft 0, and rotates while temporarily accumulating the rotational force of the motor 1.

At this time, the final workpiece and the cutting tool are not in contact with each other, and cutting work has not started.

When the rotation sensor 30 detects that the rotation speed of the motor 1 has been gradually increased to reach the desired rotation speed, the next stage of cutting operation is started.

That is, by moving the fluid pressure cylinder 6 in the opposite direction, that is, in the direction of the arrow, the biasing force of the spring 14 is removed, and the force of the spring 14 is reversed, that is, the convex connecting member 12 and the concave connecting member 16 are connected to the friction pad 17. When the connection is released, the pressing force is lost, and the two are separated and the motor 1 and the main shaft 20 are in a separated state.

However, since the flywheel 21 is connected to the main shaft 20 side and rotates at high speed together with the main shaft 20,
Even if the action of the friction clutch is discontinued, the rotation of the main shaft 20 continues due to the inertial force of the flywheel 21.

In other words, this rotation is separated from the motor 1 and is caused only by the inertial force of the flywheel 21, so vibrations caused by the motor 1 are not transmitted at all, and the rotation continues to be static, even though the rotational accuracy is extremely high. do.

The main objective of the present invention is to obtain an apparatus that performs ultra-precise cutting on a workpiece by utilizing the rotation of the main shaft due to the inertial force of the flywheel obtained as described above.

That is, after the friction clutch is disengaged, the cutting tool and the workpiece are brought into contact and machining is started.

As mentioned above, diamond bit machining for aluminum is light cutting, so the cutting force is small, and
Since the main shaft is floatingly supported by the aerostatic bearing mechanism, the idling torque of the main shaft is also small.

Therefore, the workpiece can be sufficiently machined using only the inertial force of the flywheel.

Furthermore, in addition to cutting, when mirror finishing a workpiece, there is almost no effect of the rotational speed of the spindle, so cutting can be performed with high precision.

The rotation sensor 30 detects the rotation speed of the main shaft 20, and when the clutch is connected again to increase the rotation speed of the main shaft after one process is completed and the next process starts, the motor 1 is controlled in advance by the inertia of the main shaft 20. By synchronizing the rotational speed with the rotation speed, it can be used effectively to smoothly engage the clutch in a relatively stationary state.

FIG. 3 shows a modification of the first embodiment, in which flywheels 21 and 21' are provided in a balanced manner on both sides of the front and rear ends of the main shaft 20 to maintain good balance when the main shaft rotates. I added some ideas.

That is, the number of flywheels is not limited to one, and it is natural that a plurality of flywheels may be installed.

FIG. 4 is a side sectional view showing a second embodiment of the present invention.

In this embodiment, the same components as in the embodiment shown in FIG. Instead, it has a configuration that uses an electromagnetic clutch.

That is, a rotor 31 is attached to the tip of the rotating shaft 9, and a stator 33 is fixed inside an aerostatic pressure bearing mechanism 8' that is integrated with the base 8 via a bearing 32.
An armature 35 fixed to the main shaft 20 side by a screw 34 is inserted, and the rotational force of the rotating shaft 9 is applied by friction to the main shaft 20 and the flywheel 21 integrally fixed thereto by magnetic force from a known excitation source (not shown). Disconnect from the opposite.

The main shaft 20 and the flywheel 21 are equipped with an aerostatic bearing mechanism 8
' is the same as the previous example, and the feed passage 27 piped from the air pump 26 is connected to the pocket 28.28 in the radial direction and the pocket 29.29 in the thrust direction with respect to the flywheel 21, Compressed air is blown out from each pocket to support the main shaft 20 and flywheel 21 in a floating manner.

In this example, the rotational force transmission/separation means is an electromagnetic clutch instead of a cylinder and a friction clutch, which has the advantage of simplifying the configuration.

FIG. 5 shows a third embodiment of the embodiment.

The present embodiment is the same as the second embodiment shown in FIG. A friction pad 37 is interposed between the two, so that the wheel portion 36a can be separated from the support cylinder 36 during rotation.

In other words, the supply path piped from the air pump 26 is connected to 27a and 2.
7b, and the feeding path 27a has a radial pocket portion 28.28 and a thrust direction pocket portion 29.2.
9 supports the support cylinder 36 in a floating manner, while the feed path 27b further branches into feed paths 38 and 39, and the feed path 38 is connected to a pocket portion 41 in the radial direction relative to the wheel portion 36a via a switching valve 40. , pocket portion 42 in the thrust direction
connected to.

On the other hand, the feed passage 39 is configured to be able to feed air to both sides of the piston 45 within the hollow cylinder 44 while switching the air feed direction using a two-way switching valve 43 .

This allows the piston rod 46 inside the hollow cylinder 44 to
is slidable in the vertical direction, and the piston rod 46
The cylindrical floating support part 47 integrally formed with the wheel part 36a moves in the vertical direction, and this movement causes the wheel part 36a and the support tube 3
By making only the wheel portion 36a float above the friction pad 37 that connects the wheels 6 to 6, the connection between the two can be separated.

When performing cutting work, after lowering the piston 45 using the two-way switching valve 43, the switching valve 40 is operated to cut off the air supply to the floating support section 47, and the weight of the wheel section 36a The main shaft 20, the support tube 36, and the wheel portion 36a rotate integrally and synchronously due to the frictional force with the support tube 36 via the friction pad 37, so that an inertial force is obtained.

The configuration of the electromagnetic clutch and other parts is the same as the example shown in FIG. 4, so detailed explanation will be omitted.

According to the third embodiment, the flywheel 2 is connected to the support tube 3.
6 and the wheel portion 36a, the wheel portion can be arbitrarily separated from the support tube 36 by operating the two-way switching valve 43.

If the rotational speed of the spindle 20 increases and you want to temporarily stop the rotation of the spindle 20 in order to finish the intended cutting operation and move on to the next step, the piston rod 46
When the wheel part 36a is levitated in the X direction, the rotational inertia force of the wheel part 36a to the support cylinder 36 is no longer transmitted, and the rotation of the main shaft side immediately stops, allowing the next stage to move smoothly and in a short time. can be transferred to the work of

The gist of the present invention has been explained in detail using the first to third embodiments. According to the present invention, when performing ultra-precision machining, vibrations caused by rotational power sources such as motors and belts can be reduced. It has the major feature that the curvature is not transmitted to the main shaft, which has the advantage of increasing the cutting accuracy of the workpiece, resulting in extremely high roundness or finished surface accuracy of the workpiece.

Normally, when performing light cutting using a diamond cutting tool, the finished surface accuracy is not affected by the rotational cutting speed, so one process can be completed using only the inertia of the flywheel.

In addition, if the rotational speed of the main shaft decreases during work, the rotational force transmission/separation means is connected again to increase the rotational speed of the main shaft.
It is also possible to continue the cutting operation again.

In this case, it goes without saying that the cutting operation is interrupted while the main shaft and motor are connected.

The number of flywheels is not limited to one, but it is also possible to attach a plurality of flywheels to better maintain balance, and a work chuck mechanism may be provided directly to the flywheel.

It is preferable to use a friction clutch or an electromagnetic clutch that utilizes spring pressure as the rotational force transmission and separation means.

In addition to the various advantages mentioned above, this invention also has the advantage of preventing damage or uneven wear due to vibration of the cutting tool fixed to the tool rest side, and prolonging the life of the tool, making it effective when applied to various cutting machines. It can be used for.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the first embodiment of the present invention;
The figure is a sectional view of the same side, and FIG. 3 shows the flywheel 21.
FIG. 4 is a side sectional view showing a second embodiment of the present invention, and FIG. 5 is a side sectional view showing a third embodiment of the present invention. 1...Motor, 2...Base, 3...
...Tightening bolt, 4...Flange, 5...
...Moving table, 6...Fluid pressure cylinder,
7... Information surface, Death... Base, 9...
...Rotating shaft, 12...Connecting member, 14...
... Spring, 15 ... Stopper, 16 ...
...Concave connecting member, 17...Friction pad,
19...pin, 20...main shaft, 21...
...Flywheel, 22...Connection piece, 2
3... Threaded part, 24... Nut, 25
...Flange, 26...Air pump,
27...Feeding path, 28.29...Pocket, 30...Rotation sensor, 31...
Rotor, 32... Bearing, 33... Stator, 35... Armature, 36...
・Support tube, 36a...Wheel part, 37...
... Friction pad, 38, 39 ... Feeding path, 4
0...Switching valve, 41.42...Pocket portion, 43...Two-way switching valve, 44...
・Hollow cylinder, 45... Zeston, 46...
... Piston Rondo.

Claims (5)

[Scope of utility model registration request] (1) A main shaft, a rotary power source that rotates the main shaft, a flywheel that is integrally attached to the main shaft, and a flywheel that is located between the main shaft and the rotary power source and transmits the rotational power to the output part of the rotational force transmission separation means to the main shaft. It consists of a rotational force transmission and separation means that has an input part of the rotational force transmission and separation means on the source side. During machining, the rotational power transmission and separation means separates the rotational power source and the main shaft, and the main shaft is separated by the inertia of the flywheel. A spindle rotation mechanism using a cutting machine, which is characterized by rotating. (2) The main shaft rotation mechanism in a cutting machine according to claim (1), wherein the main shaft is floatingly supported by an aerostatic bearing mechanism. (3) A main shaft rotation mechanism in a cutting machine according to claim (1), wherein a plurality of flywheels are installed on the main shaft. (4) The flywheel is rotatably supported by bearings,
A main shaft rotation mechanism for a cutting machine according to claim (1), which is configured such that the main shaft can be separated from the main shaft by a separating device during rotation. (5) A main shaft rotation mechanism in a cutting machine according to claim (1), wherein the flywheel is provided with a chuck mechanism for a workpiece.