JP2000086387A - Apparatus for pulling single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for pulling a single crystal capable of reducing the vibration of a driving system, miniaturizing the apparatus and pulling the high-quality single crystal. SOLUTION: This apparatus for pulling a single crystal is obtained by installing a motor 13 for a high speed and a motor 14 for a low speed as driving sources for hoisting, connecting a first harmonic drive gearing 17 as a speed reducer to the motor 14 for the low speed, connecting a second harmonic drive gearing 18 in series with as a speed reducer the first harmonic drive gearing 17, providing a transmitting means separate from internal teeth in a circular spline having the internal teeth of the second harmonic drive gearing 18, interlocking the transmitting means with another transmitting means connected to an output shaft of the motor 13 for the high speed, taking out a power from a flex spline of the second harmonic drive gearing 18 and carrying out the hoisting operations in the apparatus having a constitution for hoisting a wire 30 to which a seed single crystal is attached with a hoisting drum 23 and pulling the single crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single crystal pulling apparatus having a structure in which a wire to which a seed crystal is attached is wound by a winding drum to pull a single crystal.

[0002]

2. Description of the Related Art A single crystal pulling apparatus requires a very low speed feed when pulling a single crystal and a high speed feed except when pulling. Since the speed difference between the two feed operations is large, generally, two prime movers, a high speed motor and a low speed motor, are used, and switching between high speed and very low speed is performed by a clutch.

A very low speed feed requires a large reduction ratio, but conventionally, a high reduction ratio is obtained by combining a plurality of speed reducers using spur gears and worm gears. In order to connect a plurality of reduction gears, a plurality of shaft couplings are also required.

[0004]

In pulling a single crystal, extremely high-precision fine low-speed feed control is required.

[0005] However, in the conventional pulling device, since a plurality of shaft couplings and clutches are used, loss of the transmission system, speed unevenness, and occurrence of vibration cannot be avoided. When vibration due to backlash or the like increases, the quality of the pulled single crystal often deteriorates.

On the other hand, recently, a single crystal having a large diameter is pulled up, so that the apparatus tends to be complicated and large in size. From this point, simplification and downsizing of the transmission system are required.

[0007] In view of such problems of the prior art, the present invention can reduce the vibration of the drive system and can reduce the size.
It is an object of the present invention to provide a single crystal pulling apparatus capable of pulling a high quality single crystal.

[0008]

A solution of the present invention is to provide a single crystal pulling apparatus having a structure in which a wire on which a seed crystal is attached is wound up by a winding drum to pull up a single crystal. Motor and low speed motor,
A single crystal pulling device, wherein a first wave gear device is connected to a low-speed motor as a speed reducer, and a second wave gear device is connected in series to the first wave gear device.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A single crystal pulling apparatus according to the present invention has a structure in which a wire on which a seed crystal is mounted is wound by a winding drum to pull the single crystal, and a high-speed motor is provided in a drive system for winding. And a low-speed motor are separately provided, a first wave gear device is connected to the low-speed motor as a speed reducer, and a wave generator of a second wave gear device is connected in series to the first wave gear device. .

Further, it is preferable that a hard gear having internal teeth of the second wave gear device is provided with first transmission means different from the internal teeth, and the first transmission means is connected to a high-speed motor. In conjunction with the second transmission means, power is taken out from the soft gear of the second wave gear device to perform a hoisting operation.

Preferably, a gear having external teeth is fixed to the rigid gear of the second wave gear device. This gear is one aspect of the first transmission means.

The power taken from the soft gear of the second wave gear device can be transmitted directly to the hoist drum via the bearing with magnetic seal.

The first wave gear device and the second wave gear device use a 1 / 1-1 / 2 at high speed and a 1/25 at low speed.
If a reduction ratio of 00 to 1/2600 can be obtained with a clutchless structure, more preferable transmission characteristics can be obtained.

Further, by providing the brake means for the high-speed motor and the low-speed motor, the rigid gear of the second wave gear device can be reliably stopped at the time of low-speed feeding.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial sectional view showing a rotary pulling unit of the single crystal pulling apparatus of the present invention, and FIG. 2 is an enlarged sectional view showing a pulling drive unit. In the figure, the external teeth of the soft gear and the internal teeth of the hard gear in the wave gear device are omitted for clarity.

The single crystal pulling apparatus 10 pulls up a single crystal 31 from a crucible (not shown) in a melting chamber by winding a wire 30 on which a seed crystal is attached while rotating it by a rotary pulling unit 27. is there.

The rotary pulling unit 27 has a rotary stage driven by a rotary drive motor 29.
The rotating stage is a bearing unit 2 with a magnetic seal
8 supported.

A vacuum chamber 26 is provided on the rotary stage, and a winding drum 23 for winding the wire 30 is disposed therein. The shaft of the hoisting drum 23 is
It is supported by a bearing unit 24 with a magnetic seal and a normal bearing 25. Hoisting drum 23
Is connected to the pull-up drive unit 22.

The pull-up drive section 22 includes a motor 13 with a high-speed brake and a motor 14 with a low-speed brake.

A first wave gear device 17, for example, a "harmonic drive" (trade name) is connected to the output shaft of the motor 14 with a brake for low speed as a speed reducer, and further connected to the first wave gear device 17 in series. And the second wave gear device 1
8 are connected.

As is well known, the wave gear devices 17 and 18 have cylindrical hard gears (circular splines) 17a and 18a having internal teeth, external teeth having a slightly smaller number of teeth than the hard gears, and have elliptical shapes. And a flexible spline gear (flex spline) 17b, 18b composed of a cup-shaped member in which some of the teeth mesh with the internal teeth of the hard gear. The gears include wave generators (wave generators) 17c and 18c for sequentially moving the meshing positions of the external teeth with the internal teeth of the hard gear while deforming the soft gear. The wave generators 17c and 18c are constituted by members that substantially function as cams.

The first wave gear device 17 is used as a normal speed reducer.

That is, in the first wave gear device 17,
The wave generator 17c is connected to the output shaft of the low-speed brake motor 14, and is driven to rotate as the input shaft of the wave gear device 17. The hard gear 17a having internal teeth is fixedly supported by the casing. The soft gear 17b meshing with the rigid gear while deforming becomes the output shaft of the first wave generator 17 and is connected to the second wave gear unit 18.

On the other hand, the second wave gear device 18 is connected in series to the first wave gear device 17.

That is, the wave generator 18c of the second wave gear device 18 is connected to the output shaft (soft gear 17b) of the first wave gear device 17 and is driven to rotate as an input shaft. Further, the shaft of the soft gear 18b becomes the output shaft 19, and drives the winding drum 23 to rotate.

In the second wave gear device 18, the gear 16 having external teeth is coaxially fixed to the hard gear 18a. The external teeth of the gear 16 function as transmission means different from the internal teeth of the hard gear 18a. The gear 16 meshes with the gear 15 connected to the output shaft of the motor 13 with a high-speed brake.

Here, the operation of the drive unit 22 will be described.

First, the operation during high-speed feeding will be described. During high-speed feeding, the high-speed brake motor 13 is driven, and the low-speed brake motor 14 is stopped.

The rotation of the high-speed brake motor is transmitted to a gear 16 from a gear 15 provided with a backlash removing mechanism.

The gear 16 has a rigid gear 1 of a wave gear device 18.
8a is fixed and the motor 14 with the brake for low speed is stopped, the wave generator 18c does not rotate, the power is reduced from the hard gear 18a to the soft gear 18b, and the output shaft 19
Is transmitted to.

Here, the reduction ratio between the hard gear 18a and the soft gear 18b is about 1/1. The reduction ratio of gears 15 and 16 is 1 /
When i _1, the speed reduction ratio at the time of high-speed feed about ₍₁ / i 1) ·
(1/1).

The reduction ratio at the time of high-speed feeding is, for example, 1/1 to 1
/ 2 can be set.

Next, the operation during low-speed feeding will be described. At the time of low-speed feeding, the low-speed brake motor 14 is driven, and the high-speed brake motor 13 is stopped.

The rotation of the low-speed brake motor 14 is transmitted to the wave generator 17c of the first wave gear device 17,
It is taken out of the soft gear 17b after being decelerated.

Further, the rotation of the soft gear 17b is transmitted to the wave generator 18c of the second wave gear device 18. Since the motor 13 with the high-speed brake is stopped, the rigid gear 18
a does not rotate and power is supplied from the wave generator 18c to the soft gear 18
b and is transmitted to the output shaft 19.

Here, the first and second wave gear devices 17,
Assuming that the reduction ratio of 18 is 1 / i ₂ and 1 / i ₃ , the reduction ratio at the time of low-speed feeding is (1 / i ₂ ) · (1 / i ₃ ).

The reduction ratios 1 / i ₂ and 1 / i ₃ are 1 /
It can be set to about 50 to 1/160 or 1/50 to 1/160. Therefore, the net reduction ratio at the time of low-speed feeding is, for example, 1
/ 2500 to 1/2600.

In order to surely stop the hard gear 18a at the time of low-speed feeding, the two gears are slightly shifted in the rotation direction,
A motor 13 with a high-speed brake via a gear 15 with a backlash removing mechanism in which the gear is fixed by a plurality of bolts
However, it is also possible to use a high-speed geared motor without a brake, and to hold the shaft of the gear 15 with the backlash removing mechanism by the brake means.

The present invention is not limited to the above embodiment. For example, the transmission means provided on the hard gear of the second wave gear device (apart from the internal teeth) may be a pulley for driving a belt. In this case, a pulley is also provided on the output shaft of the high-speed motor, and both are linked by a belt. Further, external teeth may be formed directly on the hard gear of the second wave gear device.

[0041]

According to the single crystal pulling apparatus of the present invention, the first
By using the second wave gear device and the second wave gear device, switching between high speed and very low speed can be performed without a clutch, and vibration of the drive system caused by the clutch can be completely eliminated.

Further, by using the wave gear device, vibration of the drive system such as backlash can be reduced.

As described above, since vibration during pulling can be greatly reduced, pulling of a high-quality single crystal with stable quality can be performed.

By using the first and second wave gear devices in series, a high reduction ratio can be obtained.

Further, a large number of reduction gears and shaft couplings conventionally required can be reduced, and the driving system can be simplified to reduce the space.

Therefore, the output from the drive unit can be directly transmitted to the winding drum in the vacuum housing via the bearing unit with the magnetic seal.

Then, it is possible to reduce the size of the apparatus as a whole.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a rotary pulling unit of a single crystal pulling apparatus of the present invention.

FIG. 2 is an enlarged sectional view showing the lifting drive unit of FIG. 1;

[Explanation of symbols]

Reference Signs List 10 single crystal pulling device 13 motor with brake for high speed 14 motor with brake for low speed 15 second transmission means 16 first transmission means (gear) 17 first wave gear device 18 second wave gear device 17a, 18a circular spline ( Hard gear) 17b, 18b Flex spline (soft gear) 17c, 18c Wave generator (wave generator) 24 Bearing unit with magnetic seal 30 Wire

Claims (6)

[Claims] 1. A high-speed motor (13) as a drive source for winding in a single crystal pulling apparatus configured to pull up a single crystal by winding a wire (30) on which a seed crystal is attached by a winding drum (23). And a low-speed motor (14), a first wave gear device (17) is connected as a speed reducer to the low-speed motor (14), and a second wave gear is connected in series with the first wave gear device (17). An apparatus for pulling a single crystal, comprising an apparatus (18) connected thereto. 2. A first transmission means (16) provided on a hard gear (18a) having internal teeth of a second wave gear device (18), which is different from the internal teeth. And other second transmission means (15) connected to the high-speed motor,
The single crystal pulling apparatus according to claim 1, wherein power is taken out from the soft gear (18b) of the second wave gear device (18) to perform a hoisting operation. 3. A gear (16) having external teeth is used as said first transmission means, and said gear (16) is fixed to a rigid gear (18a) of a second wave gear device (18). The single crystal pulling apparatus according to claim 1. 4. The power taken from the soft gear (18b) of the second wave gear device (18) is transmitted to a winding drum (23) via a bearing part (24) with a magnetic seal. The single crystal pulling apparatus according to any one of claims 1 to 3. 5. The first wave gear device (17) and the second wave gear device (18) are used at a high speed in a range of 1/1 to 1/1.
2. A reduction ratio of 1/2500 to 1/2600 at low speed is obtained by a clutchless structure.
The single crystal pulling apparatus according to any one of the above. 6. The high-speed motor (13) and the low-speed motor (14) are provided with a second wave gear device (18) during low-speed feeding.
The single crystal pulling apparatus according to any one of claims 1 to 5, further comprising brake means for stopping the hard gear (18a).