JP2005147098A - Gear pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear pump suitable for use in a very small fluid volume and small output region, having excellent durability, small-sized and compact body, and good productivity. <P>SOLUTION: A motor stator 11, and a motor rotor 12 rotatably disposed outside the motor stator 11 are disposed in a motor casing 10. A pump casing 30 is hermetically connected with the motor casing 10, and has a suction port 34 and a discharge port 35. A drive gear 32 attached to one end of a shaft body 21, and a driven gear 33 are disposed in the pump casing 30. A passage is formed in a pump casing 30 so that the liquid to be handled, which is sucked from the suction port 34 by the drive gear 32 and the driven gear 33 and whose pressure is increased, is guided into the motor casing 10 by the passage. A stator can 15 is disposed to the motor stator 11 to prevent the entering of the liquid to be handled into the stator 11. A rotor can 20 is disposed to the motor rotor 12 to prevent the liquid from entering into the motor rotor 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gear pump, and more particularly, to a gear pump that is configured integrally with a motor and has high functionality and high performance.

Gear pumps are often used in applications where high pressure is required for a small flow rate, particularly pump applications used in a flow rate range of 1 liter per minute or less. This is a region where the value of the specific speed Ns is extremely small in a centrifugal pump (non-displacement pump), which is partly because it is difficult to cope with actual design. For example, when a centrifugal pump having a flow rate of 1 liter per minute and a lift of 10 meters is designed at 12000 rpm, the specific speed Ns is 67 (m ³ / min, m, min ⁻¹ ). In general, it is known that the efficiency of the centrifugal pump is significantly reduced when the value of the specific speed Ns is 70 or less. In this case, the outer diameter of the impeller is about 25 mm.

Gear pumps (external gear type) are widely used as lubricating oil pumps, fuel pumps, and the like. The fluid confined in the space formed by the two teeth and the peripheral wall is carried from the suction side to the discharge side by the rotation of the gear. When this space returns from the discharge side to the suction side, the tooth of the other gear enters the space and expels the fluid, so that the fluid cannot rotate back together with the gear teeth and return to the suction side. It is discharged outside.
JP 2000-320471 A JP-A-7-27031

  Most conventional gear pumps have a shaft seal device such as a mechanical seal in the pump portion. For this reason, in an extremely small capacity pump with a shaft power of 10 W or less, much of the shaft power is consumed by the sliding torque of the shaft seal device, and the overall efficiency is not always good. On the other hand, there is a growing need for longer life and maintenance-free in small-scale cooling devices, etc. Therefore, the pumps installed in the devices are also long-life products that do not have consumable parts such as mechanical seals. Has come to be desired. In such applications, the pump is often operated continuously at all times. For this reason, a highly efficient pump is required from the viewpoint of energy saving.

  Also, in the case of pumps for lubricants and fuels, the viscosity of the handling liquid is higher than that of water and the electrical insulation is good, so it is easy to ensure the durability of each part.・ In the system using ultrapure water, it was particularly difficult to ensure durability.

  The present invention has been made in view of the above points, and provides a gear pump that is suitable for use in the region of extremely small liquid amount and small output, has excellent durability, is small and compact, and has good productivity. With the goal.

  In order to solve the above-mentioned problem, an invention according to claim 1 is provided outside a motor stator through a motor stator and a shaft supported by a bearing provided on the motor stator in a motor casing. A motor rotor arranged in a freely rotatable manner is arranged and connected to the motor casing in an airtight state or formed integrally with the motor casing, and is attached to one end of a shaft body in a pump casing having a suction port and a pump discharge port. And a driven gear that rotates by meshing with the driving gear is arranged, and a flow path for guiding the handled liquid sucked from the suction port and pressurized by the driving gear and the driven gear into the motor casing is pumped. A stator can is provided on the casing to prevent the handling liquid from entering the motor stator, and the handling liquid is prevented from entering the motor rotor. In gear pump, characterized in that a rotor scan that.

  The invention according to claim 2 is characterized in that, in the gear pump according to claim 1, the pump casing is arranged at an upper portion of the motor casing, and a suction port and a discharge port are provided at the upper portion of the pump casing. To do.

  According to a third aspect of the present invention, in the gear pump according to the first or second aspect, a through hole through which a fluid passes is provided in the motor rotor.

  By adopting the above-described configuration in the gear pump, it is possible to provide a gear pump with less pulsation even at low speed rotation, taking advantage of the stability at low speed rotation, which is a feature of the outer rotor type motor having the motor stator arranged outside the motor stator. . Further, since a shaft seal device such as a mechanical seal is not required, a gear pump having no mechanical loss in the shaft seal device and excellent in durability can be realized.

  Since the motor casing is filled with the handling liquid, and the bearing provided on the motor stator in the motor casing is effectively lubricated by the handling liquid, durability is ensured. At this time, if a gas such as air remains in the motor casing, the gas collects in the shaft center due to the centrifugal separation action, and the lubrication of the bearing sliding portion is inhibited, but the fluid passes through the motor rotor. By providing the holes, the gas is exchanged with the inflow of the handling liquid and discharged, so that the gas does not remain in the motor casing, and the lubrication of the bearing is always maintained in a good state.

  Also, by arranging the pump casing on the upper part of the motor casing and providing the suction port and the discharge port on the upper part of the pump casing, the gas such as air existing in the motor casing and in the pump casing at the initial stage of pump operation can be easily pumped. Can be discharged outside. The gas inside the pump not only inhibits sliding lubrication but also causes pump pulsation. Further, since the internal pressure rapidly increases when the temperature rises, it is important that the gas is quickly discharged to the outside at the initial stage of pump operation.

  According to the invention described in each claim, a gear pump that is suitable for use in the region of extremely small liquid volume and small output, has excellent durability, has a simple structure, is compact and compact, and has good productivity. It becomes possible to do.

  Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 5 are views showing a configuration example of a gear pump according to the present invention, FIG. 1 is a sectional view of the entire gear pump, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 4 is a cross-sectional view taken along the line C-C in FIG. 1, and FIG. 5 is a cross-sectional view taken along the line D-D in FIG. 1. This gear pump includes a motor part M and a pump part P.

  The motor unit M is a DC brushless motor using a permanent magnet for the motor rotor 12, and includes a motor casing 10. The motor stator 11 and the motor rotor 12 are accommodated in the motor casing 10. The motor stator 11 is stably and securely fixed by fitting the inner peripheral side to the outer peripheral surface of the protrusion 13a of the end cover 13 having a sheath-shaped protrusion 13a at the center. The end cover 13 is made of, for example, aluminum die cast and is attached to the lower end of the motor casing 10 to close the lower end opening. Reference numeral 15 denotes a stator can having a sheath-shaped protrusion 15 a at the center, and the stator can 15 has an outer peripheral surface of the center-shaped sheath-shaped protrusion 15 a on an inner peripheral surface of the protrusion 13 a of the end cover 13. The inner circumferential surface is fitted to the outer circumferential surface of the motor stator winding 14.

  The bottom and front of the sheath-shaped protrusion 15a of the stator can 15 form a bearing housing, and the bearings 16 and 17 are fixed to the two bearing housings by press-fitting. The bearings 16 and 17 are so-called sliding bearings and are made of a resin material such as PEEK (polyetheretherketone). The bearings 16 and 17 are shaped according to the application, and the bearing 16 (hereinafter referred to as “front bearing”) in front of the sheath-shaped protrusion 15 a supports the radial load and the axial load of the motor rotor 12. ing. The outer diameter is increased to support the axial load.

  Further, the bearing 17 (hereinafter referred to as “rear bearing”) at the bottom of the sheath-shaped protrusion 15a supports only a radial load, and has an effect of minimizing the vibration of the motor rotor 12. Since the rear bearing 17 is configured inside the sheath-shaped protrusion 15a, the outer diameter cannot be increased. Therefore, it is configured to extend the overall length and have a PV value equivalent to that of the front bearing 16. By configuring in this way, no difference in durability occurs between the front bearing 16 and the rear bearing 17. An anti-rotation structure may be provided on the outer peripheral surface of each bearing by subjecting it to partial planar processing. When the bearing housing portion is made of resin, the bearing may be loosened with respect to the bearing housing due to the difference in linear expansion, and the anti-rotation structure is important.

  A rotor frame 19 is fixed to the outer peripheral portion of a neodymium permanent magnet 18 constituting the motor rotor 12 by adhesion or fitting. The rotor frame 19 is made of, for example, a stainless alloy. A rotor can 20 is provided so as to cover the permanent magnet 18. In order to prevent the rotor can 20 from dropping during rotation, for example, a part of the rotor frame 19 is bent. The rotor frame 19 is securely fixed to the shaft body 21 supported by the front bearing 16 and the rear bearing 17 fixed to the sheath-shaped protrusion 15a of the stator can 15 by press fitting, welding, or the like. The rotor frame 19 can be easily manufactured by processing such as press molding, thereby reducing the cost during mass production.

  Further, the outer rotor type motor has a large motor rotor 12 as a rotating body, and its mass greatly affects the power consumption. The entire weight of the child 12 can be reduced, the power consumption can be reduced, and the life of the front bearing 16 and the rear bearing 17 can be extended.

  Since the rotor can 20 provided on the inner peripheral portion of the motor rotor 12 and the stator can 15 provided on the outer peripheral portion of the motor stator 11 are made of a non-metallic resin material, these rotors are provided. No eddy current is generated in the can 20 and the stator can 15, and the motor has high efficiency because there is no eddy current loss. The reason why the rotor can 20 is provided on the inner peripheral portion of the motor rotor 12 is to prevent the handling liquid from entering the permanent magnet 18 constituting the motor rotor 12 and corroding the permanent magnet 18. The reason why the stator can 15 is provided on the outer periphery of the stator 11 is to prevent the handling liquid from entering the motor stator winding 14.

  By configuring the motor unit M as described above, the handling liquid can be used even with low electrical insulation, for example, pure water. In addition, on the outer side of the motor stator 11, heat is exchanged with the handling liquid. That is, when the handling liquid is at a normal temperature level, the motor stator 11 is cooled well. Since the mass of the motor rotor 12 greatly affects power consumption, it is extremely important to reduce the mass of the motor rotor 12 by reducing the mass of the motor rotor 12 by configuring the rotor can 20 with resin. is there.

  Since the stator can 15 and the front and rear bearings 16 and 17 are made of a resin material, the stator can 15 and the front and rear bearings 16 and 17 can be integrated using the same material, and the number of parts can be reduced. It becomes possible. Further, it is possible to integrally form the stator can 15 when forming it.

  A motor casing (motor bracket) 10 is fitted to the stator can 15, and a motor rotor chamber 22 is configured by a space surrounded by the stator can 15 and the motor casing 10. The motor casing 10 is provided with a flow path 23 into which the handling liquid flows from the pump part P. The motor rotor chamber 22 is configured to be filled with the handling liquid, and the front bearing 16 and the rear bearing 17 provided in the motor rotor chamber 22 are effectively lubricated by the handling liquid, and durability is ensured. It has become so.

  At this time, if a gas such as air remains in the motor rotor chamber 22, the gas collects in the shaft center due to the centrifugal separation effect caused by the rotation of the motor rotor 12, and the lubrication of the front bearing 16 and the rear bearing 17 is obstructed. However, in this embodiment, since the motor rotor chamber 22 is arranged vertically, the handling liquid easily flows into the motor rotor chamber 22, and the front bearing 16 and the rear bearing 17 are always good. Maintained in a lubricated state. Further, in this embodiment, the gas and handling liquid inflow holes 24 are formed in the circumferentially perpendicular plane of the rotor frame 19 so that the gas hardly remains in the motor rotor chamber 22.

  Leakage of the handling liquid to the outside, penetration of the handling liquid into the motor stator 11 part, penetration of the handling liquid into the permanent magnet 18 part of the motor rotor 12, and the motor stator winding 14 part of the motor stator 11 O-rings 25, 26, and 27 are appropriately provided at the contact portions of the respective parts in order to prevent the handling liquid from entering. Parts from the pump casing 30 to the motor casing 10 and the end cover 13 are fastened and fixed by through bolts (not shown).

  The pump part P has an inner casing 31 inside the pump casing 30 and has a double structure. In this embodiment, the inner casing 31 includes an inner casing body 31a and two side plates 31b. The side plates 31b and 31b are in contact with each other so as to sandwich the inner casing body 31a. A driven gear 33 that rotates by meshing with the drive gear 32 is accommodated. The two drive gears 32 and the driven gear 33 are made of a resin material such as PEEK or a ceramic material such as zirconia. By configuring the pump portion P as described above, the tooth side surfaces and side surfaces of the drive gear 32 and the driven gear 33 are adjusted by adjusting the tooth widths of the two drive gears 32 and the driven gear 33 and the thickness of the inner casing body 31a. The gap between the plates 31b and 31b can be appropriately managed, and the performance and efficiency of the gear pump can be improved.

  The two side plates 31b and 31b are formed with bearing through holes for supporting the shafts of the two drive gears 32 and the driven gear 33. A suction port 34 and a discharge port 35 are respectively provided (see FIG. 4). The two side plates 31b and 31b and the inner casing body 31a are each positioned by a pin. By configuring the pump in this way, the inner casing body 31a secures an appropriate clearance from the outer peripheral portions of the drive gear 32 and the driven gear 33, and the two gears of the drive gear 32 and the driven gear 33 and the inner casing 31 It is possible to prevent the drive gear 32, the driven gear 33 and the inner casing 31 from being scratched or deformed to adversely affect the performance and efficiency.

  The drive gear 32 and the driven gear 33, the inner casing body 31a and the side plates 31b and 31b are always fixed by positioning, and the inner casing body 31a and the side plates 31b and 31b are in contact with each other without being supported by the pump casing 30. The surface is fixed to some extent, and the state during pump operation can be maintained. For this reason, it is possible to cope with the failure of the pump by exchanging only the inner casing 31 part, and it is possible to improve productivity by simply performing the performance test at the time of production only with the inner casing.

  Further, according to changes in performance and requirements, it is possible to cope by exchanging only 31 parts of the inner casing. In addition, as a positioning means, the means which provides an uneven | corrugated | grooved part and fits in the inner casing main body 31a and the side plates 31b and 31b is also included. When the inner casing main body 31a and the side plates 31b and 31b are manufactured by resin formation, it is extremely advantageous from the viewpoint of reducing the number of parts and ease of assembly by providing an uneven portion and fitting them together.

  The positioning pin used for the inner casing 31 penetrates to the motor casing 10, and the inner casing 31 has a structure positioned on the motor casing. By comprising in this way, the center part of the fitting part of the drive shaft of the pump part (shaft 32a of the drive gear 32) and the motor output shaft (shaft body 21) is eliminated, and stable rotation transmission can be performed. Further, it is not necessary to perform centering at the time of assembly, which can contribute to improvement of productivity and stable supply of products.

  An elastic body 36 such as rubber is provided in the axial gap between the inner casing 31 and the pump casing 30. By comprising in this way, the leakage of the handling liquid from the clearance gap between the inner casing 31 and the pump casing 30 can be prevented, and the performance and efficiency in a gear pump can be improved. In addition, even if there is some variation in the dimensions and assembly accuracy of each part, this variation can be absorbed by the tightening allowance of the elastic body 36, so that the influence on performance and efficiency can be suppressed to a small extent. It is possible to provide a gear pump having a stable performance without any problems. The elastic body such as rubber includes resin elastomers and liquid gaskets in addition to various rubbers.

  The elastic body 36 such as rubber and the motor casing 10 are provided with flow paths 37 and 28 so that the pressure of the handling liquid is applied to the bearing through holes of the two side plates 31b and 31b (see FIG. 2). With this configuration, the pressure of the liquid to be handled is applied to both side shaft ends of the two gears of the drive gear 32 and the driven gear 33, and the operation is always performed stably, thereby improving the performance and efficiency of the gear pump. be able to.

  The pump casing 30 is provided with a suction port 34 and a discharge port 35, and the suction port 34 and the discharge port 35 communicate with a suction port 34 and a discharge port 35 (see FIG. 4) provided in the inner casing 31, respectively. doing.

  By configuring the pump part P as described above, the gas present in the pump casing 30 and the motor rotor chamber 22 of the motor casing 10 at the initial stage of the gear pump operation can be easily discharged out of the gear pump. The air present in the gear pump not only inhibits the sliding lubrication of the shafts of the front bearing 16, the rear bearing 17, the drive gear 32, and the driven gear 33, but also causes pulsation of the gear pump. In addition, since the internal pressure rapidly increases when the temperature rises, it is important to quickly discharge to the outside at the beginning of the pump operation. An O-ring 39 is appropriately provided at a contact portion between the pump casing 30 and the motor casing, and is fixed together with the motor portion M by a through bolt.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. For example, in the above embodiment, the motor casing 10 and the pump casing 30 are connected in an airtight state, but the motor casing 10 and the pump casing 30 may be integrated. It should be noted that any shape, structure, or material not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited.

1 is an overall cross-sectional view of a gear pump according to the present invention. It is AA arrow sectional drawing of FIG. It is BB arrow sectional drawing of FIG. It is CC sectional view taken on the line of FIG. It is DD sectional view taken on the line of FIG.

Explanation of symbols

P pump part M motor part 10 motor casing 11 motor stator 12 motor rotor 13 end cover 14 motor stator winding 15 stator can 16 front bearing 17 rear bearing 18 permanent magnet 19 rotor frame 20 rotor can 21 shaft body 22 motor rotor chamber 23 flow path 24 inflow hole 25 O-ring 26 O-ring 27 O-ring 28 flow path 30 pump casing 31 inner casing 32 drive gear 33 driven gear 34 suction port 35 discharge port 36 elastic body 37 flow channel

Claims (3)

In the motor casing, a motor stator and a motor rotor that is rotatably arranged outside the motor stator via a shaft body supported by a bearing provided on the motor stator,
A drive gear attached to one end of the shaft body is engaged with the drive gear in a pump casing that is connected to the motor casing in an airtight state or formed integrally with the motor casing and has a suction port and a pump discharge port. The driven gear that rotates by
The pump casing is provided with a flow path for guiding the handling liquid, which is sucked from the suction port by the driving gear and the driven gear and pressurized, into the motor casing, and the handling liquid enters the motor stator. A gear pump characterized in that a stator can for preventing the rotor is provided in the motor rotor to prevent the handling liquid from entering the stator. The gear pump according to claim 1, wherein
A gear pump characterized in that the pump casing is disposed at an upper portion of the motor casing, and the suction port and the discharge port are provided at an upper portion of the pump casing. The gear pump according to claim 1 or 2,
A gear pump characterized in that a through hole through which a fluid passes is provided in the motor rotor.

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