JP3359740B2 - Two-shaft positive displacement pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive displacement pump for delivering a fluid by moving or changing a closed space between a casing and a movable member inscribed therein, and more particularly to a two-shaft positive displacement pump comprising two shafts. is there.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 7, a pump of this type is installed separately from a pump section P and a motor M for driving the pump section P. Are connected by connecting the respective main shafts 31 and 32 with a coupling 33.

The pump section P has a casing 35 in which a pump screw 36 fixed to the main shaft 31 is provided.
And a pump screw 38 fixed to the driven shaft 37. Gears 39 and 40 meshing with each other are fixed to the main shaft 31 and the driven shaft 37, respectively.
Power is transmitted to the driven shaft 37 from the drive shaft 1. Reference numeral 41 denotes a bearing, and reference numeral 42 denotes a seal portion.

[0004]

The conventional pump shown in FIG. 7 is installed separately from the pump section and the prime mover for driving the pump as described above, and the pump section and the prime mover each have a main shaft coupled to each other. It is connected by being connected by. With this configuration, the pump section must be provided with a seal section (reference numeral 42 in FIG. 7), which requires sealing performance and maintenance of the seal section. Also, it is necessary to rotate the driven shaft of the pump section synchronously via a transmission device such as a gear, and the gear needs lubricating oil, but the problem of scattering and leakage of the lubricating oil and the problem of noise of the gear are required. There was a point.

On the other hand, even if the shaft seal portion is eliminated by using a canned motor and the motor main shaft and the pump main shaft are integrated, the driven shaft of the pump portion can be driven by a gear or the like which can rotate synchronously. A force transmission device had to be installed, which was not at a satisfactory level in terms of miniaturization, low noise and low cost.

The present invention has been made in view of this problem, and does not require a motor sealing mechanism and has two pump rotors supported in parallel without a driving force transmission device such as a gear. It is an object of the present invention to provide a two-shaft positive displacement pump that can directly perform synchronous reversal driving of a pump.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides two rotors having permanent magnets arranged around 2n poles (n is an integer) so that the permanent magnets of each rotor do not contact each other. And a magnetic coupling is formed by opposing the different magnetic pole surfaces of each rotor so that the two rotors can be easily inverted in synchronization with each other. Is provided with a pump section, and a stator for driving the two rotors in opposite directions is provided outside the permanent magnet, and the fluid or powder trapped between the casing and the pump section is inverted with respect to the two-axis rotor. In this manner, the pump is moved spatially to perform a pump action. The pump section is provided on an outer peripheral side or both side sections of the permanent magnet.

[0008]

According to the present invention, a permanent magnet is provided on the inner peripheral surface of the stator.
The two rotors provided around 2n poles (n = integer) of alternating poles and S poles are arranged while maintaining a predetermined clearance so as not to come into contact with each other, and magnetic coupling is formed by opposing the different magnetic pole faces of each rotor. Thus, a two-axis rotor in which the two rotors can be easily synchronized and inverted can be configured. The rotor is provided with a pump section, and a stator for driving the two rotors in opposite directions to each other outside the permanent magnet. A two-axis rotor is provided by a magnetic field generated by the permanent magnets provided around the two rotors and a rotating magnetic field of the stator. Is directly driven, a synchronous inversion transmission device such as a gear for synchronously inverting the two rotors is not required, and a seal mechanism between the pump unit and the motor unit can be eliminated.

Further, if the magnetic poles of the two rotors are arranged not to be the same but to be synchronously inverted at a constant rotational speed ratio corresponding to the magnetic pole ratio, for example, in the case of a screw compressor, In this manner, each pump rotor can be driven at a constant rotational speed ratio. Furthermore, by disposing the motor part consisting of the permanent magnet and the stator in the center part of the rotor, and disposing the pump parts on both sides, the thrust loads generated by the pumps on both sides are opposite to each other and cancel each other. Therefore, no thrust bearing is required. In addition, even if a slight thrust load occurs, the rotor can be pulled to the center by the attractive force between the permanent magnet and the stator even if a slight thrust load occurs, resulting in the necessity of a thrust bearing. do not do.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing one embodiment of a two-shaft positive displacement pump of the present invention, and FIG.
FIG. 2B is a sectional view taken along line I (b) -I (b) of FIG. This embodiment is configured as a two-screw pump. As shown in FIG. 1, a cylindrical pump casing 6 having both ends opened is fixed to the frame 10.
At both ends of the pump casing 6, suction casings 8 are provided.
And the discharge casing 9 are fixed. A pair of rotors Ra and Rb are provided in the pump casing 6, and the rotors Ra and Rb are rotatably supported by bearings 7. The two rotors Ra and Rb are provided circumferentially so that magnetic flux is generated in the radial direction at equal intervals symmetrically about the permanent magnets 2a and 2b of 2n poles (n is an integer). In this embodiment, each rotor Ra, R
b is n = 2, and S, N, S, N four-pole permanent magnets are provided around each rotor.

Outside the pump casing 6, stators Sa and Sb having a structure symmetrical with respect to a center line between the two rotors Ra and Rb and an extension C thereof are provided. The stators Sa and Sb are respectively composed of stator cores 1a and 1b.
And a coil 4 mounted on the stator cores 1a and 1b. In this embodiment, there are a total of six slots of three slots each having a stator core opening angle of 30 ° per rotor. With such a configuration, the stator S is configured so that the rotors Ra and Rb are continuously inverted.
When current is supplied to a and Sb, the different magnetic pole surfaces of the N pole and the S pole on the outer periphery of the rotor face each other and are synchronously inverted. At this time, a suction force acts between the two rotors simultaneously with the magnetic coupling,
In order to cancel the suction force, the rotor R on the C-axis is pulled so as to suck the same force in the opposite direction to the suction force.
Magnetic bodies 5a and 5b for balancers are arranged outside of a and Rb.

On the outermost periphery of the rotors Ra and Rb around which the permanent magnets 2a and 2b are provided, there are provided pump portions 3a and 3b each composed of a screw.
Reference numerals a and 3b are fitted to the pump casing 6 to constitute a two-shaft positive displacement pump.

Next, the operation of the two-shaft positive displacement pump constructed as described above will be briefly described. Rotors Ra, Rb
Due to the magnetic field generated in the radial direction of the 2n-pole permanent magnets 2a and 2b provided around the pump rotors, the magnetic poles of the pump rotors Ra and Rb face each other to form magnetic coupling. At the same time, the stators Sa and Sb separated by the pump casing 6 generate a rotating magnetic field such that the rotors Ra and Rb are reversed.

As described above, although magnetic attraction forces interact with the magnetically coupled rotors Ra and Rb, the magnetic members 5a and 5b for the balancer obtain magnetic forces in opposite directions to cancel the magnetic attraction forces. No excessive biasing force is applied to 7, and the rotors Ra and Rb can obtain stable rotation. By the rotation of the rotors Ra and Rb, the fluid can be transferred by the pump units 3a and 3b provided on the rotors. That is, the fluid flowing from the suction port 8a of the suction casing 8 is discharged from the discharge port 9a of the discharge casing 9 after being pressurized by the pump units 3a and 3b.

FIG. 2 is a view showing a second embodiment of the present invention. FIG. 2 (a) is a sectional view, and FIG. 2 (b) is II in FIG. 2 (a).
FIG. 2 is a sectional view taken along line (b) -II (b). This embodiment is configured as a screw compressor. In this embodiment, the number of magnetic poles of the rotor Ra and the rotor Rb is changed.
The rotor Ra has six poles and the rotor Rb has four poles. The outer peripheral lengths of the opposing different magnetic pole faces are set to the same length. The tooth ratio between the pump portions 3a and 3b provided on the outer peripheral portions of the rotors Ra and Rb is set to the same (6: 4) as the magnetic pole ratio (6: 4).

Therefore, the rotor Ra and the rotor Rb have a constant rotational speed ratio corresponding to the magnetic pole ratio, that is, the rotor Ra
And the rotor Rb are rotatable at a rotation speed ratio of 4: 6. Other configurations are the same as those of the embodiment shown in FIG.

FIG. 3 is a view showing a third embodiment of the present invention. FIG. 3 (a) is a sectional view, and FIG. 3 (b) is a sectional view of FIG. 3 (a).
FIG. 3 is a sectional view taken along the line I (b) -III (b). This embodiment is configured as an external gear pump. That is, pump portions 3a and 3b formed of external gears meshing with each other are provided on the outermost peripheral portions of the rotor Ra and the rotor Rb. Other configurations are the same as those of the embodiment shown in FIG.

FIG. 4 shows a fourth embodiment of the present invention. FIG. 4 (a) is a sectional view, and FIG.
It is a (b) -IV (b) line sectional view. This embodiment is configured as a roots type pump. That is, the rotor Ra
And the outermost portion of the rotor Rb has two leaves (Two Lob).
e) pump sections 3a and 3b are provided. Other configurations are the same as those of the embodiment shown in FIG.

FIGS. 5 and 6 show a fifth embodiment of the present invention. FIG. 5 is a sectional view, and FIG. 6 is a sectional view taken along line VI-VI of FIG. This embodiment is configured as a two-screw pump as in the first embodiment, and the pump units are arranged on both sides of the permanent magnet in the center of the rotor. 5 and 6, components having the same functions and functions as the components in FIG. 1 will be described with the same reference numerals.

As shown in FIG. 5 and FIG.
0 has a cylindrical pump casing 6 having both open ends.
6 is fixed. Brackets 12, 12 are fixed to the ends of the pump casings 6, 6, respectively. A pair of rotors Ra, Rb are disposed in the pump casings 6, 6, and the rotors Ra, Rb are provided at both ends.
Fixed bearings 7a, 7b fixed to bracket 12 and rotating bearings 8a, 8 attached to main shafts 11a, 11b.
and are rotatably supported in parallel by b. At the center of the two rotors Ra and Rb, permanent magnets 2a and 2b each having 2n poles (n is an integer) are provided circumferentially at equal intervals symmetrically about the axis so that magnetic flux is generated in the radial direction. In this embodiment, each of the rotors Ra and Rb has n = 2, and four-pole permanent magnets of S, N, S and N are provided around each rotor.

Outside the permanent magnets 2a, 2b, stators Sa, Sb having a structure symmetrical with respect to a center line between the two rotors Ra, Rb and an extension line C thereof are provided on the rotor case 13.
a, 13b and the stator cases 14a, 14b. The stators Sa and Sb include stator cores 1a and 1b, respectively, and a coil 4 mounted on the stator cores 1a and 1b. With such a configuration, if the stators Sa and Sb are energized so that the rotors Ra and Rb are continuously inverted, the N pole and S
The different magnetic pole faces of the poles are opposed to each other and synchronously inverted. At this time, a suction force acts between the two rotors at the same time as the magnetic coupling. In order to cancel the suction force, the suction force is applied in the opposite direction to the suction force by the same magnitude on the C axis. Magnetic bodies 5a and 5b for balancers are arranged outside the rotors Ra and Rb.

Further, on both sides of the permanent magnets 2a and 2b,
Pump parts 3a, 3a;
b, 3b, and these pump parts 3a, 3a;
b and 3b are fitted with the pump casing 6, respectively.
Left and right suction ports 6a, 6a are formed in the pump casing 6, and left and right discharge ports 12 are formed in the brackets 12, 12.
a, 12a are formed, thereby constituting a two-shaft positive displacement pump.

Next, the operation of the two-shaft positive displacement pump constructed as described above will be briefly described. Rotors Ra, Rb
Due to the magnetic field generated in the radial direction of the 2n-pole permanent magnets 2a and 2b provided around the pump rotors, the magnetic poles of the pump rotors Ra and Rb face each other to form magnetic coupling. At the same time, the stators Sa and Sb separated by the rotor cases 13a and 13b and the stator cases 14a and 14b
Generates a rotating magnetic field such that the rotors Ra and Rb are reversed.

As described above, magnetic attraction is mutually acting on the magnetically coupled rotors Ra and Rb. However, the bearings are provided by the balancer magnetic bodies 5a and 5b that obtain the opposite magnetic force to cancel the magnetic attraction. An excessively biased force is not applied to 7a and 7b, and stable rotation of the rotors Ra and Rb is obtained. By the rotation of the rotors Ra and Rb, the fluid can be transferred by the pump sections 3a, 3a; 3b, 3b provided on the rotors. That is, the fluid flowing from the suction ports 6a, 6a of the pump casings 6, 6
a, 3a; after the pressure is increased by 3b, 3b, the pressure is discharged from the discharge ports 12a, 12a of the left and right brackets 12, 12.

The pump thrust load generated at this time becomes opposite to each other and is canceled out to zero (0) because the pump portion is disposed on both sides of the motor portion including the permanent magnet and the stator. Therefore, the thrust bearing can be eliminated. Even if the pump thrust loads are out of balance with each other and a thrust load is generated, the thrust bearing can be eliminated because it is supported at the position of the fixed stator by the magnetic attraction of the permanent magnet.

[0026]

As described above, according to the two-shaft positive displacement pump of the present invention, the synchronous reversal of the pump rotor is directly driven, thereby eliminating the need for a seal mechanism and gears for performing the synchronous reversal, thereby providing a stable pump. A compact, low-noise and long-life pump capable of high-speed rotation can be realized.

According to the present invention, by disposing the pump sections on both sides of the motor section, the thrust load can be eliminated by the magnetic attraction of the stator and the permanent magnet, and the thrust bearing can be eliminated.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a two-shaft positive displacement pump according to the present invention, wherein FIG. 1 (a) is a cross-sectional view and FIG. 1 (b) is FIG.
It is an I (b) -I (b) line sectional view of (a).

FIG. 2 is a view showing a second embodiment of a two-shaft positive displacement pump according to the present invention, wherein FIG. 2 (a) is a sectional view and FIG. 2 (b) is FIG.
FIG. 2A is a sectional view taken along line II (b) -II (b).

FIG. 3 is a view showing a third embodiment of a two-shaft positive displacement pump according to the present invention, wherein FIG. 3 (a) is a sectional view and FIG. 3 (b) is FIG.
FIG. 3A is a sectional view taken along line III (b) -III (b).

FIG. 4 is a view showing a fourth embodiment of a two-shaft positive displacement pump according to the present invention, wherein FIG. 4 (a) is a sectional view and FIG. 4 (b) is FIG.
FIG. 4A is a sectional view taken along line IV (b) -IV (b).

FIG. 5 is a sectional view showing a fifth embodiment of a two-shaft positive displacement pump according to the present invention.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5;

FIG. 7 is a sectional view showing a conventional two-shaft positive displacement pump.

[Explanation of symbols]

 Ra, Rb Rotor Sa, Sb Stator 1a, 1b Stator core 2a, 2b Permanent magnet 3a, 3b Pump unit 4 Coil 5a, 5b Magnetic body for balancer 6 Pump casing 7 Bearing 8 Suction casing 9 Discharge casing 10 Frame 11a, 11b Main shaft 12 Bracket 13a, 13b Rotor case 14a, 14b Stator case

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasushi Kube 11-1 Haneda Asahimachi, Ota-ku, Tokyo Ebara Corporation (56) References JP-A-63-302189 (JP, A) JP-A-60-81488 (JP, A) JP-A-2-153281 (JP, A) JP-A-53-101103 (JP, A) JP-A-4-1755491 (JP, A) JP-A-6-4385 (JP) , U) Japanese Utility Model Hei 3-23679 (JP, U) Japanese Utility Model Application Sho 53-57307 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04C 2/16 F04C 2/18 F04C 18/16 F04C 18/18

Claims (5)

(57) [Claims] 1. Two rotors having permanent magnets arranged around 2n poles (n is an integer) are arranged while maintaining a predetermined clearance so that the permanent magnets of the rotors do not come into contact with each other. A two-axis rotor is formed so as to oppose a magnetic coupling so that the two rotors can be easily and reversibly synchronized with each other. The rotor is provided with a pump unit, and the two rotors are provided outside the permanent magnet. A stator for driving the fluid in the opposite directions to each other, and performing a pumping action by spatially moving the fluid or powder confined between the casing and the pump unit by inverting the two-axis rotor. Features a two-shaft positive displacement pump. 2. The pump unit according to claim 1, wherein the stator is divided without intersecting the center line of the two-axis rotor and an extension of the two-axis rotor and obtaining a suction force in a direction opposite to a suction force between the rotors. 2. The two-shaft positive displacement pump according to claim 1, wherein the two-shaft positive displacement pump is disposed on an outer periphery of the pump. 3. The apparatus according to claim 1, wherein the two rotors are not made to have the same number of magnetic poles, and the two-axis rotors are synchronously inverted at a constant rotational speed ratio according to the magnetic pole number ratio.
Or the two-shaft positive displacement pump according to 2. 4. The two-shaft positive displacement pump according to claim 1, wherein the pump section is provided on an outer peripheral side of the permanent magnet. 5. The two-shaft positive displacement pump according to claim 1, wherein the pump section is provided on both sides of the permanent magnet.