JPS62291486A - Screw compressor - Google Patents

Abstract

PURPOSE:To enable the rotors of a screw compressor to rotate at a high speed by making the lead number of each thread even, and providing a cavity in each of the thread ridges at both ends of the respective rotors. CONSTITUTION:The static balance is set by making the thread length T of each of rotors 3 even times as long as the thread lead L thereof. Cavities 3b are respectively provided in the thread ridges (heavy parts) on both ends of the threads 3a of the rotors 3. The dynamic balance is set by fusing and fixing a light metal such as aluminum and the like, in each of the hollow part 3b. It is possible to make the rotors 3 rotate at a high speed.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention improves the method of balancing the rotor of a spiral screw compressor/nocer that generates vibration in the high-speed rotation region, and This invention also relates to a spiral screw combination soar that does not generate vibration.

[Conventional technology and problems]

The generally known screw compressor is
It is called TWIN 5CREW COMPRESSOR and is a product of SRM of Sweden.As shown in Figures 5 and 6, it consists of a main shaft 1 with multiple threads and a sub-shaft 2 with a thread that meshes with the main shaft. It consists of two rotors and a casing surrounding the two rotors.

The rotor has an easy-to-balance shape and can be used for relatively high-speed rotation, but on the other hand, it has a large number of teeth (number of threads) and the tooth profiles of the main shaft and sub-shaft are different. For these reasons, it is necessary to improve the meshing accuracy, and the current situation is to polish the parts with a full-form grindstone after milling or hobbing.

Therefore, the manufacturing cost is very high, and the applications are currently limited.

In addition, large capacity compressors are difficult to manufacture because they require high precision and special machine tools, so generally the ones on the market are at most lQr+? /m1n (inhalation state) is common.

Therefore, the pressure increase is usually 1 kg/cn! Currently, for blowers with a large air volume of G or higher, measures such as multi-stage Roots blowers are being taken.

However, the Roots blower is large in size, and if it is made into a multi-stage type, it not only requires a large installation area, but also costs more, and has the disadvantage that efficiency is lowered due to belt loss and the like due to the multi-stage design.

Therefore, a spiral screw compressor can be considered as an alternative to the Roots blower, but as shown in Figure 4, the thread formed by the Archinedes curve C+, the Quimby curve C2, and the circle C3 is oriented toward the center of the rotor. Generally, it was impossible to operate at a rotation speed of 1500 rpm or more because the mass was uneven and severe vibration occurred as the rotation increased.

If the rotation speed could only be used in a low speed range, the amount of air discharged would be small, and the drawback was that it would be larger than a normal compressor or Roots blower.

Moreover, when the pressure is increased, the amount of leakage also increases accordingly, resulting in a problem of decreased efficiency.

Since the amount of leakage is considered to be constant regardless of the rotation speed, the higher the rotation speed, the higher the volumetric efficiency will be.It is desirable to increase the rotation speed of the compressor, but in a spiral screw compressor, the mass relative to the center of the rotor is Due to the non-uniformity, vibrations become more intense with high-speed rotation, and it is generally impossible to operate at a rotation speed of 1500 rpm or higher.

Therefore, in order to take advantage of the advantages of a spiral screw compressor and use it efficiently, it is essential to be able to use it even in a high-speed rotation range, and for that purpose, the rotor balance must be G2.5 or higher according to JISBO905. was there.

The present invention solves the above problems and provides a spiral screw compressor that enables high-speed rotation by improving the rotor balancing method.

[Means for solving problems]

The present invention makes the number of leads of the screws of the rotor of a spiral screw compressor an even number, and also provides a cavity in the screw threads at both ends of the rotor, or casts a lightweight material into the part provided with the cavity. The reason is that the weight has been reduced and the rotor has been balanced.

〔Example〕

There are two types of balance: static balance and dynamic balance. In the case of a single thread screw, achieving static balance is achieved by multiplying the number of leads by an even number.

However, dynamic balance leaves unbalanced masses at both ends of the screw, which causes vibrational force.

That is, if the unbalanced mass existing at the screw end is m and the rotation speed is N, then the centrifugal force F is where, T: radius, ω:
It is the rotational angular velocity.

Therefore, if the screw length T is an even multiple of the length L as shown in FIG.
Here, 2n means an even number multiple.

For this reason, when the rotation speed is increased, vibrations occur due to the force couple, making it impossible for the compressor to rotate at high speed.

Based on this fact, it was conventionally said that it was impossible to balance the rotor.

As shown in FIG. 3, the present invention provides a screw length T of the rotor 3.
Static balance is maintained by setting the torsion to an even multiple of L, and as shown in Fig. The dynamic balance is achieved by providing a cavity 3b at a 180 degree angle (l6) or by welding a lightweight metal such as aluminum to the hollowed part 3b.

By achieving dynamic balance as described above, the spiral screw compressor can operate at high speeds from N=150 Orpm before balancing to more than N=360 Orpm, and can blow a large amount of air with a compact compressor. We were able to obtain a high-performance compressor that is quiet and has little vibration.

In addition, this compressor boosts the pressure to 1 kg f/cI+
! It can also be used as a blower for the following: 1600mm in one stage
It is an epoch-making device that can also be used as a vacuum pump capable of suctioning HgG, and its range of applications is wide.

〔effect〕

The present invention maintains static balance by making the screw length an even multiple of the lead, and dynamically balances the unbalanced mass by casting a material with a light specific gravity or creating a cavity, thereby reducing rotor rotation. It is now possible to operate at high speeds from 150 Orpm to over 360 Orpm.

Therefore, by increasing the speed of the compressor, it was possible to increase efficiency and create a compressor with less vibration and noise.

That is, compared to the conventional multi-stage Roots blower, the installation area is reduced to 1/2, and the shaft power can be reduced by approximately 15%.

[Brief explanation of the drawing]

Figures 1 to 3 show embodiments of the present invention, Figure 1 is a front view of the rotor showing parts that are lighter due to hollow rotor, etc., and Figures 2 (a) and (b) are the same as above. A and B arrow views, Figure 3 is a front view of a rotor with a thread length that is an even number multiple of the lead, Figure 4 is a thread outline of a spiral screw, and Figures 5 and 6 are a general screw compressor. FIG. 2 is a threaded external view of the rotor and a perspective view of the rotor. 3...Rotor, T...screw length, L...lead. Patent applicant: Taiko Kikai Kogyo Co., Ltd. (A)
(b) Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] In a spiral screw compressor that has a pair of rotors with a single right-handed and left-handed screw having a tooth profile consisting of a Quimby curve and an Archimedes curve, the number of leads of the screws is an even number, and cavities are provided in the threaded portions at both ends of the rotor. A screw compressor is characterized by having a lightweight material cast into the hollow part to reduce weight and balance the rotor.