阅读说明：本技术 带推力控制的压缩机 (Compressor with thrust control ) 是由 V·M·西什特拉 于 2020-05-11 设计创作，主要内容包括：一种电马达包括定子和构造成相对于定子旋转的转子。定子具有长度L_s,且转子具有长度L_r。转子的长度L_r小于定子的长度L_s,使得转子不伸出定子。还公开了一种压缩机和压缩流体的方法。(An electric motor includes a stator and a rotor configured to rotate relative to the stator. The stator has a length L s And the rotor has a length L r . Length L of rotor r Less than the length L of the stator s So that the rotor does not protrude beyond the stator. A compressor and a method of compressing a fluid are also disclosed.)

1. An electric motor comprising:

a stator; and

a rotor configured to rotate relative to the stator, wherein the stator has a length L_sAnd the rotor has a length L_rAnd wherein the length L of the rotor_rLess than the length L of the stator_sSo that the rotor does not protrude beyond the stator.

2. An electric motor according to claim 1, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between the lengths L of the rotors_rBetween about 1% and 5%.

3. An electric motor according to claim 2, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between the lengths L of the rotors_rBetween about 1% and 3%.

4. An electric motor according to claim 3, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between is the length L of the rotor_rAbout 1.5%.

5. The method of claim 1Characterized in that the length L of the rotor_rAnd the length L of the stator_sThe difference between is the length L of the rotor_rAbout 2 to 5 times the predetermined manufacturing tolerance value.

6. An electric motor according to claim 5, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between is the length L of the rotor_rAbout 2 to 3 times the predetermined manufacturing tolerance value.

7. The electric motor of claim 1, wherein the electric motor is an electric motor in a compressor, and the electric motor is configured to drive at least one impeller via a shaft.

8. A compressor, comprising:

an electric motor, comprising:

a stator; and

a rotor configured to rotate relative to the stator, wherein the stator has a length L_sAnd the rotor has a length L_rAnd wherein the length L of the rotor_rLess than the length L of the stator_s；

At least one impeller configured to be driven by the electric motor via a shaft; and

at least one bearing configured to facilitate rotation of the shaft.

9. The compressor of claim 8, wherein the compressor is a centrifugal compressor.

10. The compressor of claim 8, wherein the compressor is configured to compress a fluid, and the fluid is a refrigerant.

11. The compressor of claim 8, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between the lengths L of the rotors_rBetween about 1% and 5%.

12. The compressor of claim 11, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between the lengths L of the rotors_rBetween about 1% and 3%.

13. The compressor of claim 12, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between is the length L of the rotor_rAbout 1.5%.

14. The compressor of claim 8, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between is the length L of the rotor_rAbout 2 to 5 times the predetermined manufacturing tolerance value.

15. The compressor of claim 14, wherein the length L of the rotor_rAnd the length L of the stator_sThe difference between is the length L of the rotor_rAbout 2 to 3 times the predetermined manufacturing tolerance value.

16. The compressor of claim 8, further comprising at least one balance piston configured to balance aerodynamic forces on the shaft, the aerodynamic forces being substantially aligned with an axis of the compressor.

17. The compressor of claim 16, wherein a sum of electromagnetic forces generated by the electric motor in a direction generally aligned with the axis is less than about 10% of the aerodynamic force.

18. A method of compressing a fluid, comprising:

rotating an impeller with an electric motor, the impeller configured to compress a fluid, the electric motor comprising:

a stator; and

a rotor configured to rotate relative to the stator, wherein the stator has a length L_sAnd the rotor has a length L_rAnd wherein the length L of the rotor when the rotor is rotating_rLess than the length L of the stator_s。

19. The method of claim 18, wherein an electric motor rotates the impeller via a shaft, and wherein at least one bearing facilitates rotation of the shaft.

20. The method of claim 18, wherein the fluid is a refrigerant.

Background

The compressor compresses fluid by rotating one or more impellers via a shaft. For example, in a centrifugal compressor, the shaft and impeller may be rotated by a motor, such as an electric motor. For example, in a centrifugal compressor, an impeller imparts kinetic energy to a fluid, which then passes through a diffuser that slows the flow of the fluid and converts the kinetic energy into an increase in pressure (e.g., compression).

During operation of the compressor, forces generated within the compressor may cause the compressor components to become misaligned with one another. Misalignment can cause wear and shorten the life of certain compressor components.

Disclosure of Invention

An electric motor according to an example of the present disclosure includes a stator and a rotor configured to rotate relative to the stator. The stator has a length L_sAnd the rotor has a length L_r. Length L of rotor_rLess than the length L of the stator_sSo that the rotor does not protrude beyond the stator.

In another example of the foregoing embodiment, the length L of the rotor_rLength L of stator_sThe difference between them being over the length L of the rotor_rBetween about 1% and 5%.

In another example of any of the foregoing embodiments, the length L of the rotor_rLength L of stator_sThe difference between them being over the length L of the rotor_rBetween about 1% and 3%.

In another example of any of the foregoing embodiments, the length L of the rotor_rLength L of stator_sThe difference between is the length L of the rotor_rAbout 1.5%.

In another example of any of the foregoing embodiments, the length L of the rotor_rLength L of stator_sThe difference between them being over the length L of the rotor_rBetween about 2 and 5 times the predetermined manufacturing tolerance value.

In another example of any of the foregoing embodiments, the length of the rotorL_rLength L of stator_sThe difference between them being over the length L of the rotor_rBetween about 2 and 3 times the predetermined manufacturing tolerance value.

In another example of any of the preceding embodiments, the electric motor is an electric motor in a compressor, and the electric motor is configured to drive the at least one impeller via a shaft.

A compressor according to an example of the present disclosure includes an electric motor, a stator, and a rotor configured to rotate relative to the stator. The stator has a length L_sAnd the rotor has a length L_r. Length L of rotor_rLess than the length L of the stator_s. At least one impeller is configured to be driven by an electric motor via a shaft. At least one bearing is configured to facilitate rotation of the shaft.

In another example of the foregoing embodiment, the compressor is a centrifugal compressor.

In another example of any of the foregoing embodiments, the compressor is configured to compress a fluid, and the fluid is a refrigerant.

In another example of any of the foregoing embodiments, the length L of the rotor_rLength L of stator_sThe difference between them being over the length L of the rotor_rBetween about 1% and 5%.

In another example of any of the foregoing embodiments, the length L of the rotor_rLength L of stator_sThe difference between them being over the length L of the rotor_rBetween about 1% and 3%.

In another example of any of the foregoing embodiments, the length L of the rotor_rLength L of stator_sThe difference between is the length L of the rotor_rAbout 1.5%.

In another example of any of the foregoing embodiments, the length L of the rotor_rLength L of stator_sThe difference between them being over the length L of the rotor_rBetween about 2 and 5 times the predetermined manufacturing tolerance value.

In another example of any of the foregoing embodiments, the length L of the rotor_rLength L of stator_sThe difference between being in the rotorLength L_rBetween about 2 and 3 times the predetermined manufacturing tolerance value.

In another example of any of the preceding embodiments, the at least one balance piston is configured to balance aerodynamic forces on the shaft, and the aerodynamic forces are substantially aligned with an axis of the compressor.

In another example of any of the preceding embodiments, a sum of the electromagnetic forces generated by the electric motor in a direction generally aligned with the axis is less than about 10% of the aerodynamic force.

A method of compressing a fluid according to an example of the present disclosure includes: an impeller is rotated with an electric motor, the impeller configured to compress a fluid. The electric motor includes a stator and a rotor configured to rotate relative to the stator. The stator has a length L_sAnd the rotor has a length L_r. Length L of rotor when rotor is rotating_rLess than the length L of the stator_s。

In another embodiment of the foregoing method, the electric motor rotates the impeller via a shaft, and the at least one bearing facilitates rotation of the shaft.

In another example of any of the foregoing methods, the fluid is a refrigerant.

Drawings

Fig. 1 schematically shows a compressor.

Fig. 2 schematically shows a detailed view of the motor of the compressor of fig. 1.

Detailed Description

An exemplary compressor 10 is schematically illustrated in fig. 1. In this example, the compressor 10 is a centrifugal compressor, although other compressors are contemplated by the present disclosure. The compressor 10 includes a suction (inlet) port 12 and a discharge (outlet) port 14. The compressor 10 includes one or more impellers 16 that rotate to draw fluid from the suction port 12 and compress the fluid. An exemplary fluid is a refrigerant.

An electric motor 18 drives the impeller 16 via a shaft 20. Bearings 21 facilitate rotation of shaft 20. In this example, the compressor 10 comprises one shaft 20 driving two impellers 16, each associated with a suction port 12 and a discharge port 14, although other arrangements are conceivable.

The motor 18 includes a stator 22 and a rotor 24. As is well known, the stator 22 remains stationary while the rotor 24 rotates due to electromagnetic forces generated by the interaction of the rotor 24 and the stator 22. The rotor 24 rotates the shaft 20, which in turn rotates the impeller 16 as described above.

During operation of compressor 10, axial forces, such as those generally aligned with axis a of compressor 10, are generated by aerodynamic and electromagnetic forces. These axial forces are represented by additive vectors and may be collectively characterized as the "net thrust" of compressor 10. The axial force may cause various components of compressor 10 to be urged out of alignment with one another. This in turn can cause stress and wear on the bearing 21, particularly if the fluid is a low viscosity fluid like a refrigerant. Thus, reducing the axial force (e.g., reducing the "net thrust") improves the life of the bearing 21 and, in some cases, allows for the use of a smaller bearing 21.

Axial aerodynamic forces are generated by fluid traveling through compressor 10 and being compressed. In one example, axial aerodynamic forces are controlled or reduced by a balance piston 26 on the shaft 20. In the example of fig. 2, there is one balance piston 26 associated with each impeller 16, but more or fewer balance pistons 26 may be used. The balance pistons 26 are arranged and sized in a manner such that they balance the axial aerodynamic forces exerted on the shaft 20 to reduce the overall axial aerodynamic forces within the compressor 10.

The axial electromagnetic force is generated by misalignment of the rotor 24 relative to the stator 22. Misalignment may be caused by displacement of the rotor 24 and stator 22 during operation of the motor 18 and/or a dimensional mismatch of the rotor 24 and stator 22 due to manufacturing tolerances. Specifically, as the rotor 24 extends out of the stator 22 on either side, the axial electromagnetic force increases. That is, during operation, the rotor 24 may be displaced in either axial direction from being centered relative to the stator 22 such that the protrusion occurs on one side of the rotor 24. Additionally or alternatively, the overhang may be caused by a length mismatch of the rotor 24 and stator 22, for example due to manufacturing tolerances in the case where the rotor 24 is slightly longer than the stator 22.

Fig. 2 shows a detailed view of the motor 18. As shown, the rotor 24 has a length L_rLess than the length L of the stator 22_s. Length L_sChosen to minimize the protrusion of the rotor 24 as described above. Alternatively, when the rotor 24 is centered relative to the stator 22, as shown in fig. 2, the stator 22 protrudes the rotor 24 distances D1 and D2 on either side. Thus, the length L of the rotor 24_rLength L of stator 22_sThe difference Δ therebetween is equal to the sum of D1 and D2. Because of the length L of the rotor 24_rLess than the length L of the stator 22_sSo that no axial displacement of the rotor 24 relative to the stator 22 or manufacturing tolerances will cause protrusion.

In a particular example, the difference Δ is over the length L of the rotor 24_rBetween about 1 and 5%. For example, if the rotor 24 has a length of 10 inches (25.4 centimeters), the difference Δ is between about 0.1 inches (2.54 millimeters) and 0.5 inches (12.7 millimeters), and the stator 22 has a length of between about 9.9 inches (25.1 centimeters) and 9.5 inches (24.1 centimeters). .

In a more specific example, the difference Δ is over the length L of the rotor 24_rBetween about 1% and 3%.

In a more specific example, the difference Δ is about the length L of the rotor 24_r1.5% of.

In another example, the difference Δ is between about 2 to 5 times the manufacturing tolerance of the length of the rotor 24. The manufacturing tolerance for the length of the rotor 24 is a predetermined tolerance value. For example, in this example, if the rotor 24 is at a desired length L that must be at the rotor 24_rIs manufactured to within 0.1 inch (2.54 millimeters), the difference delta is between about 0.2 (5.08 millimeters) and 0.3 inches (7.62 millimeters).

In a more specific example, the difference Δ is between about 2 to 3 times the manufacturing tolerance of the length of the rotor 24.

The compressor 10 as described above with the stator 22 and the rotor 24 (with the difference Δ in their respective lengths) results in a lower axial electromagnetic force, because the difference Δ ensures that the rotor 24 does not protrude beyond the stator 22. As a result, the bearing 21 is subjected to less stress and wear. Thus, the life of the bearing 21 is improved, and in some cases, a smaller bearing 21 may be used.

In one example, the axial electromagnetic force caused by the compressor 10 as described above with the stator 22 and rotor 24 (having the difference Δ in their respective lengths) is about 10% or less of the axial aerodynamic force described above.

The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.