JP2014206072A - Gear pump and electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear pump that can control both thermal expansion in a radial direction and thermal expansion in an axial direction of a gear pump rotor to suppress meshing imbalance between gear teeth, and also can enhance a pump efficiency, and to provide an electric pump.SOLUTION: In the gear pump, the gear pump rotor 40 is accommodated in a pump housing chamber 33 formed in a pump enclosure 31. An outer rotor 41 and an inner rotor 42 of the gear pump rotor 40 are formed of super engineering plastic. The super engineering plastic contains carbon fiber F so that the longitudinal direction of the carbon fiber F is oriented in the radial direction. The gear pump rotor 40 has a lower thermal expansion in the radial direction than that in the axial direction.

Description

  The present invention relates to a gear pump and an electric pump.

  Conventionally, in a gear pump, a gear pump rotor housed in a pump housing chamber is made of resin instead of iron, and it has been proposed to achieve corrosion resistance and weight reduction to achieve high pump efficiency ( For example, Patent Document 1).

  Further, fiber reinforced resin gear pump rotors have been proposed in which fillers such as glass fibers are kneaded to increase the strength of resin gear pump rotors (for example, Patent Document 2 and Patent Document 3).

Japanese Utility Model Publication No. 62-11348 Utility Model Registration No. 3046977 Japanese Utility Model Publication No. 63-1028

  By the way, in the resin-made gear pump rotor (which is the same for metal), power loss due to sliding friction between the gear pump rotor and the pump housing occurs, and volume efficiency increases as the clearance between the gear pump rotor and the pump housing increases at high temperatures. It has become a problem that it falls.

Therefore, when the liquid to be pumped is at a high temperature (for example, about 200 ° C.), it is desirable to allow a predetermined thermal expansion in the axial direction of the gear pump rotor.
However, if excessive thermal expansion in the axial direction is allowed, thermal expansion in the radial direction of the gear pump rotor causes imbalance between the inner teeth of the outer rotor of the gear pump rotor and the outer teeth of the inner rotor, resulting in excessive engagement of the teeth. There is a possibility that biting occurs and the contact surface pressure is increased.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to control the gear pump rotor thermal expansion in the radial direction and the thermal expansion in the axial direction so that the meshing unbalance between the gear teeth. It is providing the gear pump and electric pump which can suppress pumping and can improve pump efficiency.

  In order to solve the above-mentioned problems, a gear pump includes an outer rotor having inner teeth on the inner side, and an inner rotor having outer teeth that are disposed on the inner side of the outer rotor and rotate integrally with a rotation shaft and mesh with the inner teeth of the outer rotor. A gear pump rotor, and a pump housing having a pump housing chamber surrounding the gear pump rotor so as to oppose both the outer side surface and the outer circumferential surface in the axial direction of the gear pump rotor, wherein the gear pump rotor has a shaft It was more difficult to thermally expand in the radial direction than in the direction.

  According to this configuration, even if the liquid temperature and the outside air temperature change, thermal expansion in the radial direction of the gear pump rotor is suppressed, and the occurrence of meshing imbalance between the external teeth and the internal teeth can be suppressed. Further, when the liquid temperature or the outside air temperature is low, the gear pump rotor is thermally contracted in the axial direction, and friction between the gear pump rotor and the pump housing can be reduced.

The said structure WHEREIN: It is preferable that both the inner rotor and outer rotor of the said gear pump rotor consist of the same material.
According to this configuration, since the inner rotor and the outer rotor are made of the same material, wear hardly occurs between the external teeth and the internal teeth that mesh with each other. Further, since the inner rotor and the outer rotor are made of the same material, the linear expansion coefficient is the same, so that the meshing between the gear teeth is good.

  In the above configuration, the molding base material of the gear pump rotor including the inner rotor and the outer rotor is made of a resin containing a fibrous filler, and the fibrous filler contained in the molding base material is It is preferable that the gear pump rotor is formed to be less likely to thermally expand in the radial direction than in the axial direction by being oriented so that the longitudinal direction is directed to the radial direction of the gear pump rotor.

  According to this configuration, since the resin-made gear pump rotor is used, the gear pump rotor can be reduced in weight and power efficiency can be improved, and the gear pump rotor can be easily molded. Further, since the fibrous filler is dispersed so that the fiber orientation is longitudinal in the radial direction, thermal expansion in the radial direction of the gear pump rotor can be suppressed, while thermal expansion in the axial direction is allowed. be able to.

The said structure WHEREIN: It is preferable that the said fibrous filler is a fiber which has lubricity.
According to this configuration, power loss due to friction between the gear pump rotor and the pump housing can be reduced.

The said structure WHEREIN: It is preferable that the fiber which has the said lubricity is a carbon fiber.
According to this configuration, power loss due to friction between the gear pump rotor and the pump housing can be reduced.

The said structure WHEREIN: It is preferable that the shaping | molding base material of the said gear pump rotor consists of super engineering plastics.
According to this configuration, while being lighter than metal, it is rich in heat resistance, strength, and the like, and it is possible to ensure improvement in pump efficiency and reliability as a product equivalent to metal.

The said structure WHEREIN: It is preferable that the shaping | molding base material of the said gear pump rotor consists of self-lubricating resin.
According to this configuration, in addition to the friction between the gear pump rotor and the pump housing, the friction between the inner rotor and the outer rotor of the gear pump can be reduced, which can contribute to the reduction of power loss.

The said structure WHEREIN: It is preferable that the said inner rotor is formed so that at least one part of the said rotating shaft may be embedded at the time of shaping | molding.
According to this configuration, the rotary shaft does not need to be press-fitted and fixed to the resin inner rotor, and deformation of the inner rotor due to press-fitting does not occur. Therefore, it is possible to avoid the deterioration of the engagement between the external teeth and the internal teeth by connecting and fixing the inner rotor to the rotating shaft.

The said structure WHEREIN: It is preferable that the inner rotor of the said gear pump rotor formed the notch recessed part in the predetermined location of at least any one outer surface of both axial direction outer surfaces.
According to this configuration, since the notch recess is formed on the outer surface in the axial direction of the inner rotor, the friction area between the outer surface in the axial direction of the inner rotor and the pump housing can be reduced, so that friction can be reduced.

The said structure WHEREIN: It is preferable that the outer rotor of the said gear pump rotor formed the notch recessed part in the axial direction in the predetermined location of at least any one outer surface of both axial direction outer surfaces.
According to this configuration, since the notch recess is formed in the outer side surface of the outer rotor in the axial direction, the friction area between the outer side surface of the outer rotor in the axial direction and the pump housing can be reduced, so that the friction can be reduced.

In order to solve the above-described problem, an electric pump is provided with a motor that rotates and rotates a rotation shaft provided in the gear pump to any one of the above-described gear pumps.
According to this configuration, an electric pump that increases pump efficiency can be realized by using a gear pump rotor that is less likely to thermally expand in the radial direction than in the axial direction.

The said structure WHEREIN: It is preferable that the rotating shaft provided in the said gear pump shared the rotating shaft of the said motor.
According to this configuration, by making the rotation shaft of the gear pump and the rotation shaft of the motor the same, it is possible to realize a motor with a small required torque, and it is possible to reduce the size of the motor and the electric pump.

  ADVANTAGE OF THE INVENTION According to this invention, while controlling the thermal expansion to the radial direction and axial expansion of a gear pump rotor, the meshing imbalance between gear teeth can be suppressed, and pump efficiency can be improved.

Sectional drawing which shows the state which assembled | attached the electric pump of 1st Embodiment to the transmission. Similarly, the front view seen from the axial direction for demonstrating the motor rotor of an electric pump. Similarly, the front view seen from the axial direction for demonstrating the gear pump rotor of an electric pump. Similarly, the perspective view for demonstrating the gear pump rotor of an electric pump. Similarly, the sectional view on the AA line of FIG. The front view seen from the axial direction for demonstrating the gear pump rotor of the electric pump of 2nd Embodiment. Similarly, the BB sectional drawing of FIG. The front view seen from the axial direction which shows another example of the gear pump rotor of an electric pump. Similarly, the CC sectional view taken on the line of FIG. Sectional drawing seen from the radial direction which shows the shape of the filler of another example. Sectional drawing seen from the radial direction which shows the orientation of the filler of another example.

(First embodiment)
Hereinafter, an embodiment of an electric pump will be described with reference to FIGS.
As shown in FIG. 1, the electric pump 1 of this embodiment is an electric oil pump that is mounted on a transmission 2 mounted on a vehicle and supplies hydraulic oil of an oil pan (not shown) to the transmission 2. The electric pump 1 is assembled in such a manner that a part of the electric pump 1 is embedded in a pump mounting recess 3 that is recessed in the wall surface 2 a of the main body of the transmission 2.

  The pump mounting recess 3 is a recess having a circular cross section, and an inner peripheral surface 3 a thereof is an arc surface centered on the central axis L <b> 1 of the pump mounting recess 3. The inner peripheral surface 3a of the pump mounting recess 3 is formed so as to expand toward the opening, and the expanded surface is used as a fitting surface 3b.

  An oil outlet passage 4 having a circular cross section is formed in the inner surface 3c of the pump mounting recess 3. The oil lead-out path 4 is formed at a position where the center axis L2 is parallel to the center axis L1 of the pump mounting recess 3 and deviates from the center axis L1. The pump mounting recess 3 is formed with an oil introduction path (not shown) communicating with the oil pan on the inner peripheral surface 3a near the back surface 3c.

As shown in FIG. 1, the electric pump 1 assembled in the pump mounting recess 3 includes a motor unit 10, a circuit unit 20, and a pump unit 30.
(Motor unit 10)
The motor unit 10 includes a motor case 11 made of a substantially cylindrical metal material (preferably iron) that is closely fitted and fixed to the fitting surface 3 b of the pump mounting recess 3. The motor case 11 is formed so that the central axis of the inner peripheral surface thereof coincides with the central axis L1 of the pump mounting recess 3. Further, the motor case 11 has a thick portion 11 a having an outer peripheral surface near the opening of the pump mounting recess 3 having a large diameter, and the outer peripheral surface of the thick portion 11 a serves as a fitting surface 3 b of the pump mounting recess 3. Close fitting.

  The motor case 11 is formed with a flange 11b extending outward in the radial direction on the entire circumference of the end of the pump mounting recess 3 on the opening side. The flange portion 11b is in contact with the wall surface 2a in which the pump mounting recess 3 is provided, and is fixed to the wall surface 2a. The circuit unit 20 is connected to the flange portion 11 b of the motor case 11. In addition, a pump unit 30 is connected to the opening of the motor case 11 on the side of the rubbing portion 11b.

  As shown in FIG. 1, an annular motor stator 12 is fixed to the inner peripheral surface of the motor case 11. The motor stator 12 has a stator core 13 made of a plurality of electromagnetic steel plates laminated in the axial direction. The stator core 13 is formed with a plurality of teeth 13a extending radially inward, and a coil 14 is wound around each tooth 13a.

  The outer peripheral surface of the stator core 13 is in metal contact with the inner peripheral surface of the motor case 11. The central axis of the motor stator 12 is configured to coincide with the central axis of the motor case 11 (the central axis L1 of the pump mounting recess 3). The coil 14 is inserted into a space (slot) formed between the circumferential directions of the teeth 13a.

  As shown in FIG. 1, a motor rotor 15 is disposed inside the motor stator 12. The motor rotor 15 includes a rotating shaft 16 and a substantially cylindrical rotor core 17 in which a plurality of electromagnetic steel plates are laminated in the axial direction and are fitted and fixed (press-fit) to the rotating shaft 16. The rotary shaft 16 is made of stainless steel, which is a nonmagnetic metal, and the central axis O thereof is arranged so as to coincide with the central axis of the motor case 11, that is, the central axis L 1 of the pump mounting recess 3. The output end of the rotary shaft 16 protrudes to the pump unit 30 described later, is rotatably supported by the pump unit 30, and drives the pump unit 30.

  As shown in FIG. 2, a plurality of (four in this embodiment) magnet magnetic pole portions 18 a that are radially opposed to the teeth 13 a of the stator core 13 are formed at equal intervals in the circumferential direction. . Each magnet magnetic pole portion 18 a is formed by embedding a plate-like magnet 19 in the peripheral portion of the rotor core 17. That is, the motor rotor 15 of the present embodiment is configured as an embedded magnet type (IPM type) motor rotor.

  Specifically, magnet housing holes 17a drilled in the axial direction are provided at the peripheral edge portion of the rotor core 17 at equal intervals (90-degree intervals) in the circumferential direction, and the radial direction of the rotor core 17 is provided in each magnet housing hole 17a. Each magnet magnetic pole portion 18a is formed by accommodating and fixing each magnet 19 in an orthogonal manner. Each magnet 19 is disposed so that the magnetic pole surface on the radially outer side of the rotor core 17 has the same polarity (for example, S pole). As a result, four magnet magnetic pole portions 18a having the same polarity (S pole) are formed in the motor rotor 15 at substantially equal intervals (approximately 90 ° intervals) along the circumferential direction. Between the circumferential directions of the magnet magnetic pole portions 18a, an iron core portion 18b of the rotor core 17 is formed to project outward in the radial direction. Then, due to the magnetic action of the magnet 19, a pseudo N-pole magnetic pole having a polarity different from that of the adjacent magnet magnetic pole part 18a is formed in each iron core part 18b. That is, the motor rotor 15 is configured as a so-called continuous pole type rotor.

  Here, the number of slots of the motor stator 12 (the number of teeth 13a) is set to an integral multiple of the number of magnet magnetic pole portions 18a. That is, in this embodiment, since the number of the magnet magnetic pole portions 18a is 4, the number of slots of the teeth 13a is set to an integral multiple of 4. As a result, when a certain magnet magnetic pole portion 18a faces one tooth 13a, the magnet magnetic pole portion 18a and the tooth 13a also face each other at other locations. Can be reduced.

(Circuit unit 20)
As shown in FIG. 1, the circuit unit 20 includes a circuit case 21 that closes the flange 11b side opening of the motor case 11 and is fixed to the wall surface 2a of the transmission 2 together with the flange 11b. Yes. In the circuit case 21, a circuit board 23 on which various circuit elements 22 for controlling the rotation of the motor unit 10 are mounted is accommodated.

(Pump unit 30)
As shown in FIG. 1, the pump unit 30 includes a pump housing 31 made of an aluminum material that is a columnar nonmagnetic metal that closes the opening of the motor case 11 on the side of the flange 11 b. The end of the pump casing 31 on the side of the motor case 11 has a large diameter, and the outer peripheral surface of the large diameter section is press-fitted and fixed to the inner peripheral surface of the opening portion of the motor case 11 near the pump casing 31. Has been.

  The cylindrical pump housing 31 has a fitting recess 32 formed in the outer surface on the side of the motor case 11 in the axial direction, and the fitting recess 32 has a pump housing whose diameter is smaller than the inner diameter of the fitting recess 32 on the back surface. The chamber 33 is recessed.

  The fitting recess 32 has a pump housing in which the axis-perpendicular section of the inner peripheral surface thereof is a circle centered on the central axis O (center axis L1) of the rotating shaft 16 and is recessed in the inner surface of the fitting recess 32. A lid portion 34 that closes the chamber 33 in a liquid-tight manner is fitted.

  The lid 34 is made of an aluminum material that is the same nonmagnetic metal as the pump housing 31, and forms a pump housing with the pump housing 31. The cover part 34 is formed with a shaft support hole 34a penetrating in the axial direction at the center position, and projects the rotating shaft 16 of the motor part 10 into the pump housing chamber 33 and rotatably supports it. The distal end portion of the rotating shaft 16 protruding into the pump housing chamber 33 is fitted and supported rotatably in a shaft supporting recess 33 a that is recessed in the inner surface of the pump housing chamber 33.

  The pump housing chamber 33 has a circular shape with the axis orthogonal cross section of the inner peripheral surface thereof centered on the axis (eccentric axis Ox) at a position eccentric with respect to the central axis O (center axis L1) of the rotating shaft 16. A gear pump rotor 40 is disposed in the pump storage chamber 33.

  As shown in FIGS. 3 and 4, the gear pump rotor 40 is a toroidal type (inscribed gear type) gear pump rotor, and includes an outer rotor 41 and an inner rotor 42. When the number of teeth 41a formed on the radially inner surface of the outer rotor 41 is n (n is a natural number of 3 or more), the number of teeth 42a formed on the radially outer surface of the inner rotor 42 is n-1. There is an individual relationship. In the present embodiment, the number of teeth of the inner teeth 41a of the outer rotor 41 is five, and the number of teeth of the outer teeth 42a of the inner rotor 42 is four.

  The outer rotor 41 is housed in the pump housing chamber 33 such that its radially outer circumferential surface 41b is in sliding contact with the inner circumferential surface 33b of the pump housing chamber 33 and is rotatable. That is, the outer rotor 41 is housed in the pump housing chamber 33 so as to be rotatable about the eccentric axis Ox that is the central axis of the pump housing chamber 33 as a rotation center.

  The inner rotor 42 is disposed on the inner side of the outer rotor 41, is fixed to the rotary shaft 16 that penetrates the pump housing chamber 33, and rotates integrally with the rotary shaft 16. That is, the inner rotor 42 rotates about the central axis O of the rotation shaft 16 as the rotation center.

  As a result, the outer rotor 41 is assembled eccentrically with respect to the inner rotor 42, and the outer teeth 41 are rotated in accordance with the rotation of the inner rotor 42 by engaging the inner teeth 41a and the outer teeth 42a having different numbers of teeth. Rotate following direction. In addition, the volume of the gap between the outer rotor 41 and the inner rotor 42 varies depending on the position due to the eccentric assembly and the different number of teeth.

  Then, a suction port (not shown) is provided at a position where the volume starts to increase, and a discharge port 33c having a small volume is provided, so that the pump unit 30 sucks the hydraulic oil from the suction port and the hydraulic oil from the discharge port 33c. Performs a pumping action to discharge water.

Accordingly, when the motor unit 10 is driven and the rotating shaft 16 rotates, the pump unit 30 performs a pumping action.
As shown in FIG. 1, the pump housing 31 has a cylindrical discharge port 43 protruding from the outer surface on the side opposite to the motor case 11 in the axial direction. The center axis of the discharge port 43 is shifted from the center axis L1 of the pump mounting recess 3 and coincides with the center axis L2 of the oil outlet path 4 formed on the inner surface 3c of the pump mounting recess 3, and the oil outlet path 4 The opening inner peripheral surface 4a is inserted and connected. The discharge port 43 communicates the discharge port 33c of the pump storage chamber 33 and the oil outlet passage 4 and also prevents a ball 44a from preventing the oil from flowing from the oil outlet passage 4 to the discharge port 33c of the pump storage chamber 33. A check valve 44 is provided from the compression coil spring 44b.

  An oil inflow space S is formed between the pump housing 31 and the pump mounting recess 3 on the outer peripheral portion of the pump housing 31. In the oil inflow space S, hydraulic oil from the oil pan is introduced through an oil introduction path (not shown) formed in the inner peripheral surface 3 a of the pump mounting recess 3. The hydraulic oil introduced into the oil inflow space S is supplied to a suction port (not shown) of the pump housing chamber 33 via a guide passage (not shown) formed in the pump housing 31.

Next, the material of the outer rotor 41 and the inner rotor 42 of the gear pump rotor 40 will be described.
In the present embodiment, the outer rotor 41 and the inner rotor 42 are made of a resin excellent in heat resistance, durability, and mechanical properties (abrasion resistance and impact strength) as a molding base material, for example, a polyimide material or a polyamide. Molded with super engineering plastic made of materials.

  As shown in FIGS. 1 and 5, the outer rotor 41 and the inner rotor 42 contain carbon fibers F as fillers (fillers) in the super engineering plastic. The carbon fiber F has a linear expansion coefficient smaller than the linear expansion coefficient of the super engineering plastic that is the forming base material. And the carbon fiber F is orientated so that the longitudinal direction of the carbon fiber F is directed in the radial direction, and is contained in the super engineering plastic.

  That is, the carbon fiber F of the outer rotor 41 is oriented so that the longitudinal direction of the carbon fiber F is directed in the radial direction with the eccentric axis Ox as the central axis, and is contained in the super engineering plastic. As a result, the outer rotor 41 has a smaller thermal expansion than the thermal expansion in the axial direction due to the orientation of the carbon fibers F.

  On the other hand, the carbon fiber F of the inner rotor 42 is oriented so that the longitudinal direction of the carbon fiber F faces the radial direction with the central axis O of the rotating shaft 16 as the central axis, and is contained in the super engineering plastic. As a result, the inner rotor 42 has a smaller thermal expansion in the radial direction than in the axial direction due to the orientation of the carbon fibers F.

  Note that the carbon fibers F as fillers shown in FIGS. 1 and 5 are exaggerated for easy understanding. Further, the carbon fibers F shown in FIGS. 1 and 5 are expressed as being contained in the outer rotor 41 and the inner rotor 42, but some of the carbon fibers F are both in the axial direction of the outer rotor 41 and the inner rotor 42. It is exposed to form part of the outer surface. Similarly, a part of the carbon fibers F is exposed so as to form a part of the radially outer side surface and the inner side surface of the outer rotor 41 and the inner rotor 42.

Next, the operation of the electric pump 1 configured as described above will be described.
When the motor unit 10 is driven and the rotary shaft 16 rotates, the inner rotor 42 of the pump unit 30 rotates. When the inner rotor 42 rotates, the outer rotor 41 in which the outer teeth 42a and the inner teeth 41a of the inner rotor 42 mesh with each other is driven to rotate in the same direction. Thus, the gear pump rotor 40 housed in the pump housing chamber 33 performs a pumping action of sucking the working oil from the suction port and discharging the working oil from the discharge port 33c.

  Further, since the outer rotor 41 and the inner rotor 42 are formed of super engineering plastic, the gear pump rotor 40 is light in weight, reduced in power loss, and excellent in heat resistance and strength, and has the same reliability as that of metal. Sex is secured.

  At this time, since the outer rotor 41 and the inner rotor 42 are made of the same material, wear hardly occurs between the engaging inner teeth 41a and outer teeth 42a. Further, since the outer rotor 41 and the inner rotor 42 are made of the same material, the linear expansion coefficient is the same, and the engagement between the inner teeth 41a and the outer teeth 42a is improved.

  Further, the outer rotor 41 and the inner rotor 42 contain carbon fibers having a linear expansion coefficient smaller than that of the super engineering plastic in the super engineering plastic so that the longitudinal direction of the carbon fibers F is directed in the radial direction. Oriented. And about the outer rotor 41 and the inner rotor 42, it is made for the thermal expansion to radial direction to become smaller than the thermal expansion to an axial direction.

  Thereby, even if the oil temperature or the outside air temperature of the hydraulic oil becomes high, the thermal expansion in the radial direction of the gear pump rotor 40 is suppressed, so that the meshing imbalance between the external teeth 42a and the internal teeth 41a is suppressed, There is no risk of teeth biting too much and biting.

  In addition, when the oil temperature or the outside air temperature of the hydraulic oil is low, the gear pump rotor 40 is thermally contracted in the axial direction, so that both axially outer side surfaces of the gear pump rotor 40 form the pump housing chamber 33. Friction when sliding between the casing 31 and the lid portion 34 can be reduced.

  At this time, since the carbon fiber F is a lubricating fiber, the friction when sliding between the pump casing 31 surrounding the gear pump rotor 40 and the lid 34 can be reduced, and the power loss due to the friction can be reduced. can do.

Next, the effect of the said embodiment is described below.
(1) According to this embodiment, the outer rotor 41 and the inner rotor 42 contain the carbon fiber F having a small linear expansion coefficient in the super engineering plastic so that the longitudinal direction of the carbon fiber F faces the radial direction. Oriented. Thereby, the outer rotor 41 and the inner rotor 42 have a smaller thermal expansion in the radial direction than in the axial direction.

  Therefore, even if the oil temperature or the outside air temperature of the hydraulic oil becomes high, thermal expansion in the radial direction of the gear pump rotor 40 can be suppressed, the meshing imbalance between the external teeth 42a and the internal teeth 41a is suppressed, and the teeth mesh with each other. You can prevent biting. Further, when the oil temperature or the outside air temperature of the hydraulic oil becomes low, the gear pump rotor 40 is thermally contracted in the axial direction, so that both axially outer side surfaces of the gear pump rotor 40 form the pump housing chamber 33. Friction when sliding between the casing 31 and the lid portion 34 can be reduced.

Therefore, the motor unit 10 having a small output torque can be used, and an electric pump having a small size and high pump efficiency can be realized.
(2) According to the present embodiment, since the outer rotor 41 and the inner rotor 42 are formed of super engineering plastic, the gear pump rotor 40 is light in weight, can reduce power loss, and is excellent in heat resistance and strength. Reliability equal to that of the product can be ensured.

  At this time, since the outer rotor 41 and the inner rotor 42 are formed of the same material, wear does not easily occur between the meshing inner teeth 41a and the outer teeth 42a, and the linear expansion coefficient is the same, so that the inner teeth 41a and the outer teeth 42a mesh. Will also be good.

  (3) According to the present embodiment, since the carbon fiber F contained in the outer rotor 41 and the inner rotor 42 formed of super engineering plastic is a lubricious fiber, the pump casing 31 and the lid that surround the gear pump rotor 40 The friction at the time of sliding with the part 34 can be reduced, and the power loss due to the friction can be reduced.

Therefore, the motor unit 10 having a smaller output torque can be used, and an electric pump having a smaller size and higher pump efficiency can be realized.
(4) According to the present embodiment, since the rotation shaft 16 of the motor unit 10 is also used as a rotation shaft for directly rotating the inner rotor 42 of the gear pump rotor 40 provided in the pump unit 30, the power loss can be reduced. The motor unit 10 having a small output torque can be used, and a smaller electric pump with high pump efficiency can be realized.

(Second Embodiment)
Next, 2nd Embodiment of an electric pump is described according to FIG.6 and FIG.7.
Since the present embodiment is characterized by the gear pump rotor 40, the gear pump rotor 40 will be described in detail, and the configuration common to the first embodiment will be omitted for convenience of description. And of course, the gear pump rotor 40 of this embodiment is used for the electric pump 1 of 1st Embodiment.

  As shown in FIGS. 6 and 7, the outer rotor 41 and the inner rotor 42 of the gear pump rotor 40 are formed of super engineering plastic containing carbon fibers F, as in the first embodiment. And the carbon fiber F is orientated so that the direction of the longitudinal direction of the carbon fiber F may turn to radial direction like 1st Embodiment.

  First notch recesses 41d are respectively provided in the axial direction at positions corresponding to the inner teeth 41a on the both outer side surfaces 41c of the outer rotor 41 in the axial direction. 41 d of 1st notch recessed parts are dented so that the cross-sectional shape of an axial orthogonal direction may be elliptical.

  On the other hand, the second notch recesses 42d are respectively provided in the axial direction at positions corresponding to the outer teeth 42a on both axially outer side surfaces 42c of the inner rotor 42. The second cutout recess 42d has a rectangular cross-sectional shape in the direction perpendicular to the axis.

Next, the operation of the gear pump rotor 40 configured as described above will be described.
First notch recesses 41d are formed on both outer side surfaces 41c of the outer rotor 41 in the axial direction. Therefore, the friction area between the inner surface of the pump housing chamber 33 slidably in contact with both outer axial surfaces 41c of the outer rotor 41 and the side surface of the lid housing 34 on the side of the pump housing chamber 33 is reduced, and sliding friction is reduced.

  Similarly, second notch recesses 42d are formed in both axially outer side surfaces 42c of the inner rotor 42, respectively. Therefore, the friction area between the inner surface of the pump housing chamber 33 and the side surface on the side of the pump housing chamber 33 on the lid portion 34 slidably in contact with both axially outer side surfaces 42c of the inner rotor 42 is reduced, and sliding friction is reduced.

Next, in addition to the effect of 1st Embodiment, the said embodiment has the following effects.
(1) According to the present embodiment, the first notch recesses 41 d are respectively provided in the axially outer side surfaces 41 c of the outer rotor 41, and the second notch recesses 42 d are respectively recessed in the axially outer side surfaces 42 c of the inner rotor 42. Set up. The outer side surfaces of the gear pump rotor 40 in the axial direction can reduce the friction area between the inner surface of the pump housing chamber 33 that is in sliding contact with the outer surfaces of the gear pump rotor 40 and the side surface of the lid housing 34 on the side of the pump housing chamber 33. To reduce.

Therefore, the motor unit 10 having a smaller output torque can be used, and a smaller electric pump with high pump efficiency can be realized.
In addition, you may change each said embodiment as follows.

  In each of the above embodiments, the carbon fiber F is used as the filler (filler). However, if the filler is oriented so that the longitudinal direction of the filler is in the radial direction, other linear expansion such as glass fiber is possible. You may implement using a filler with a small ratio.

Even in this case, the thermal expansion in the radial direction of the outer rotor 41 and the inner rotor 42 can be made smaller than the thermal expansion in the axial direction.
In each of the above embodiments, the gear pump rotor 40, that is, the outer rotor 41 and the inner rotor 42 are molded from super engineering plastic. This may be performed by molding with a self-lubricating resin such as polyamide or polyacetal as a molding base material. Of course, fillers (fillers) such as carbon fibers and glass fibers are contained in the self-lubricating resin, and the longitudinal direction of fillers (fillers) such as carbon fibers and glass fibers is the radial direction. Of course, it is oriented so as to face the direction.

  In this case, both axial outer side surfaces of the gear pump rotor 40 can reduce sliding friction with the inner surface of the pump housing chamber 33 that is in sliding contact with the outer surfaces of the gear pump rotor 40 and the side surface of the lid housing 34 on the pump housing chamber 33 side. In addition, friction between the outer rotor 41 and the inner rotor 42 can be reduced. As a result, the power loss is reduced, and the motor unit 10 having a small output torque can be used, and a small-sized electric pump with high pump efficiency can be realized.

  In the first embodiment, the rotation shaft 16 of the motor unit 10 is configured to be rotatably supported by the shaft support recess 33 a that has a tip penetrating the inner rotor 42 and formed in the inner surface of the pump housing chamber 33. . Alternatively, the rotation shaft 16 may be fixed to the inner rotor 42 without the shaft support recess 33 a and without causing the tip of the rotation shaft 16 to protrude from the inner rotor 42.

  Further, when the inner rotor 42 and the rotating shaft 16 are fixed integrally, when the inner rotor 42 is resin-molded using a mold, outsert molding, that is, in a state where the rotating shaft 16 is disposed in the cavity of the mold. Alternatively, the inner rotor 42 and the rotating shaft 16 may be fixed integrally by injecting resin.

  In this case, the rotary shaft 16 does not need to be press-fitted and fixed to the resin inner rotor 42, so that the inner rotor 42 is not deformed by press-fitting. As a result, it is possible to avoid the deterioration of the meshing of the outer teeth 42a and the inner teeth 41a due to the connection and fixing of the inner rotor 42 to the rotating shaft 16.

  In the second embodiment, the first notch recesses 41 d are respectively provided in the both axial outer side surfaces 41 c of the outer rotor 41, and the second notch recesses 42 d are respectively provided in the both axial outer side surfaces 42 c of the inner rotor 42. .

This may be carried out by omitting the cutout concave portion of either the outer rotor 41 or the inner rotor 42.
In addition, although the first notch recess 41d is provided in each of the axially outer side surfaces 41c of the outer rotor 41, the first notch recess 41d may be provided only in one of the outer side surfaces 41c. Similarly, although the second notch recesses 42d are respectively provided in the both axial outer side surfaces 42c of the inner rotor 42, the second notch recess 42d may be provided only in one of the outer side surfaces 42c.

  In the first embodiment, as shown in FIGS. 8 and 9, the first resin member 51 that is a resin that does not contain a filler and has a large linear expansion coefficient is applied to both axially outer side surfaces 41 c of the outer rotor 41. Or it adheres and adheres by outsert. Similarly, a second resin member 52 that is a resin that does not contain a filler and has the same linear expansion coefficient as the first resin member 51 is applied or adhered to the both outer side surfaces 42c of the inner rotor 42 by adhesion or outsert. Stick.

Thereby, the thermal expansion in the axial direction can be made larger than the thermal expansion in the radial direction of the outer rotor 41 and the inner rotor 42.
In each of the above embodiments, the outer rotor 41 or the inner rotor 42 is molded from resin. A plurality of reinforced sheets having a very low linear expansion coefficient such as metal sheets and super engineering plastic sheets are laminated, and a resin sheet having a higher linear expansion coefficient than the reinforced sheet is interposed between the reinforced sheets and the reinforced sheets. May be carried out. Thereby, the thermal expansion in the radial direction of the outer rotor and the inner rotor can be made smaller than the thermal expansion in the axial direction.

In each of the above embodiments, the carbon fiber F is a straight fiber as a filler (filler), but may be a crimped carbon fiber F (filler) as shown in FIG.
In each of the above embodiments, the carbon fibers F as fillers (fillers) are oriented so that the longitudinal direction is in the radial direction. However, the orientation in which the longitudinal direction is oriented in the radial direction is, as shown in FIG. 11, oriented so that the carbon fibers F are not parallel to the axial direction but inclined toward the outside in the radial direction as seen from the radial direction. It is also included when doing.

  In addition, in the orientation in which the longitudinal direction is directed in the radial direction, in addition to the orientation state shown in each of the above embodiments and FIG. The case where it is oriented is also included.

  In each of the above embodiments, the inner teeth 41a of the outer rotor 41 and the outer teeth 42a of the inner rotor 42 are formed in a spur gear shape, but may be implemented in a helical gear shape.

  DESCRIPTION OF SYMBOLS 1 ... Electric oil pump (electric pump), 2 ... Transmission, 2a ... Wall surface, 3 ... Pump mounting recessed part, 3a ... Inner peripheral surface, 3b ... Fitting surface, 3c ... Back surface, 4 ... Oil lead-out path, 4a ... Inner peripheral surface of the opening, 10 ... motor part, 11 ... motor case, 11a ... thick part, 11b ... collar part, 12 ... motor stator, 13 ... stator core, 13a ... teeth, 14 ... coil, 15 ... motor rotor, 16 ... rotation Shaft, 17 ... rotor core, 17a ... magnet housing hole, 18a ... magnet magnetic pole part, 18b ... iron core part, 19 ... magnet, 20 ... circuit part, 21 ... circuit case, 22 ... circuit element, 23 ... circuit board, 30 ... pump , 31 ... Pump housing, 32 ... Fitting recess, 33 ... Pump housing chamber, 33 a ... Shaft support recess, 33 b ... Inner peripheral surface, 33 c ... Discharge port, 34 ... Lid, 34 a ... Shaft support hole, 40 ... Gear pump rotor, DESCRIPTION OF SYMBOLS 1 ... Outer rotor, 41a ... Internal tooth, 41b ... Outer peripheral surface, 41c ... Outer side surface (axial direction), 41d ... 1st notch recessed part, 42 ... Inner rotor, 42a ... Outer tooth, 42c ... Outer side surface (axial direction), 42d ... 2nd notch recessed part, 43 ... discharge port, 51, 52 ... 1st and 2nd resin member, L1, L2, O ... center axis, Ox ... eccentric axis, S ... oil inflow space, F ... carbon fiber.

Claims (12)

A gear pump rotor comprising: an outer rotor having inner teeth on the inner side; and an inner rotor disposed on the inner side of the outer rotor and integrally rotated with a rotating shaft and having outer teeth meshing with the inner teeth of the outer rotor;
A gear pump comprising: a pump housing having a pump housing chamber that surrounds the both axial outer side surfaces and the radially outer peripheral surface of the gear pump rotor;
The gear pump rotor, wherein the gear pump rotor is formed to be less susceptible to thermal expansion in the radial direction than in the axial direction. The gear pump according to claim 1, wherein
An inner rotor and an outer rotor of the gear pump rotor are both made of the same material. The gear pump according to claim 1 or 2,
The molding base material of the gear pump rotor composed of the inner rotor and the outer rotor is made of a resin containing a fibrous filler, and the fibrous filler contained in the molding base material is oriented in the longitudinal direction. Is oriented so as to face the radial direction of the gear pump rotor, the gear pump rotor is formed so as to be less susceptible to thermal expansion in the radial direction than in the axial direction. The gear pump according to claim 3,
The gear pump, wherein the fibrous filler is a fiber having lubricity. The gear pump according to claim 4,
The gear pump according to claim 1, wherein the fiber having lubricity is a carbon fiber. In the gear pump according to any one of claims 3 to 5,
A gear pump characterized in that a molding base material of the gear pump rotor is made of super engineering plastic. In the gear pump according to any one of claims 3 to 5,
A gear pump characterized in that a molding base material of the gear pump rotor is made of a self-lubricating resin. The gear pump according to any one of claims 3 to 7,
The gear pump is characterized in that the inner rotor is formed so as to embed at least a part of the rotating shaft during molding. In the gear pump according to any one of claims 1 to 8,
An inner rotor of the gear pump rotor is characterized in that a notch recess is formed at a predetermined location on at least one of the outer surfaces in the axial direction. In the gear pump according to any one of claims 1 to 9,
The outer pump of the gear pump rotor is characterized in that a notch recess is formed in the axial direction at a predetermined location on at least one of the outer surfaces in the axial direction. The electric pump which attached the motor which rotationally drives the rotating shaft provided in the gear pump to the gear pump as described in any one of Claims 1-10. The electric pump according to claim 11, wherein
An electric pump characterized in that a rotating shaft provided in the gear pump also serves as a rotating shaft of the motor.