JP2022181280A - electric pump - Google Patents

Abstract

To constitute an electric pump that changes the speed of driving force of an electric motor and transmits it to a pump part without causing an increase in size.SOLUTION: An electric pump comprises: an electric motor M comprising a field coil 15 arranged in an annular region around a driving axis X, and a motor rotor 16 supported rotatably around the driving axis X; a speed change part G for changing the speed of rotation of the motor rotor 16 and transmitting it to a driving shaft S; a pump part P to be driven by driving force of the driving shaft S; and a housing H for housing each of the electric motor M, the speed change part G, the driving shaft S, and the pump part P. The motor rotor 16 comprises a permanent magnet 16b on an outer peripheral side of a cylindrical yoke 16a around the driving axis X. The speed change part G is housed in an internal space of the yoke 16a.SELECTED DRAWING: Figure 1

Description

The present invention relates to electric pumps.

2. Description of the Related Art Patent Document 1 and Patent Document 2 disclose electric pumps that transmit the driving force of an electric motor to a pump section by means of a gear-type reduction mechanism.

The electric pump (pump unit in the literature) of Patent Document 1 accommodates an electric motor, a pump drive shaft to which the driving force of the electric motor is transmitted, and a pump to which the force from the pump drive shaft is transmitted, in a unit housing. .

In the electric pump of Patent Document 1, the pump is configured as an internal gear pump having an inner gear (pump rotor) and an outer gear, and a speed change device consisting of a planetary gear type speed reducer is incorporated inside the inner gear. is configured to decelerate the driving force of and transmit it to the inner rotor.

In the electric pump of Patent Document 2 (two-system drive pump in the document), a planetary gear mechanism to which the driving force of the engine and the like and the driving force of the electric motor are transmitted is accommodated in the housing, and the driving force from the planetary gear mechanism is accommodated in the housing. to the pump mechanism is accommodated in the housing.

In the electric pump of Patent Document 2, when the engine is driven, the electric motor is energized so as to keep the carrier of the planetary gear mechanism stationary, and the driving force of the engine rotates the ring gear to drive the pump. Also, when the engine is stopped, the ring gear is stationary, so by driving the electric motor, the driving force of the electric motor is transmitted from the pinion of the planetary gear mechanism to the sun gear to drive the pump. .

JP 2012-189012 A JP 2019-100320 A

For example, considering an electric pump for supplying hydraulic oil in a vehicle, it is necessary to drive the electric pump with high torque when the viscosity of the hydraulic oil is high, such as in a low temperature environment. For this reason, a reduction gear is required to reduce the driving force of the electric motor and transmit it to the pump.

In order to address such a problem, it is possible to reduce the driving force of the electric motor and transmit it to the pump rotor in the case of an electric pump in which a planetary gear type speed reducer is accommodated in the pump rotor, such as the electric pump described in Patent Document 1. Become. On the other hand, since the planetary gear reducer is housed in the inner gear, the pump rotor becomes large, which not only increases the outer diameter of the rotor but also requires a clearance between the pump rotor and the planetary gear reducer. Therefore, there is a concern that the meshing of the rotor is likely to fluctuate due to load fluctuations, etc., leading to an increase in pulsation and operating noise.

In addition, in a structure that transmits two systems of driving force to a planetary gear mechanism like the electric pump described in Patent Document 2, it is possible to transmit reduced driving force to the pump. However, it was conceivable that when the electric motor was driven while the engine was stopped, the pump would rotate at a high speed, reducing the efficiency of the pump and increasing noise.

Since the electric pump described in Patent Document 2 uses a planetary gear mechanism, the pump can be driven simultaneously by the driving force of the engine and the electric motor, but the pump is driven by the driving force of the engine. In that case, it was necessary to supply current to the electric motor only to stop the rotation of the carrier, and the current was wasted.

For these reasons, there is a demand for an electric pump that changes the speed of the driving force of the electric motor and transmits it to the pump section without increasing the size.

A characteristic configuration of the electric pump according to the present invention includes a field coil arranged in an annular region around the drive shaft core, and a magnetic field of the field coil supported rotatably around the drive shaft core. an electric motor having a motor rotor that rotates due to action; a transmission section that changes the speed of rotation of the motor rotor and transmits it to a drive shaft; a pump section that is driven by the driving force of the drive shaft; the electric motor, the transmission section, the A drive shaft and a housing that accommodates the pump section are provided, and the motor rotor includes a permanent magnet on the outer peripheral side of a cylindrical yoke centered on the drive shaft core. It lies in that it is accommodated in the inner space of the yoke.

According to this characteristic configuration, when the pump section is driven, a current is supplied to the field coil to rotate the motor rotor. It is transmitted to the pump section, and the pump section is driven. In addition, since the transmission section is arranged inside the yoke that constitutes the motor rotor, for example, the internal space of the electric motor can be effectively used to shift gears without forming a space for arranging the transmission section inside the housing. It becomes possible to place the part. Moreover, in this characteristic configuration, the size of the pump portion is not increased as in Patent Document 1.
Accordingly, an electric pump has been constructed in which the driving force of the electric motor is changed and transmitted to the pump portion without causing an increase in size.

As a configuration in addition to the above configuration, the housing has a projecting portion projecting in the direction of the transmission portion inside the housing so as to support the drive shaft in a penetrating state, and the motor rotor is rotatable. A supporting bearing may be supported in contact with the protrusion.

According to this, for example, a ball bearing or a roller bearing is used as the bearing, and the motor rotor can be stably rotated only by supporting the inner race of the bearing in a state such as being externally fitted to the projecting portion of the housing. Supportable.

As a configuration in addition to the above configuration, the transmission unit includes a sun gear, a ring gear arranged in a region surrounding the sun gear, and a plurality of planetary gears meshing with the sun gear and the ring gear. It may be configured as a planetary gear type that changes the speed of the driving force and transmits it to the drive shaft.

According to this, by configuring the transmission portion in a planetary gear type, it is possible to perform transmission at a large transmission ratio while suppressing an increase in size.

In addition to the above configuration, the transmission unit includes a sun gear, a ring gear arranged in a region surrounding the sun gear, a plurality of planetary gears meshing with the sun gear and the ring gear, and a carrier supporting the plurality of planetary gears. The driving force transmitted from the motor rotor is configured as a planetary gear type to transmit the driving force transmitted from the motor rotor to the drive shaft after changing the speed, and the pump section rotates in conjunction with the first inner rotor and the first inner rotor. a first internal gear type pump mechanism having one outer rotor; and a second pump mechanism having a second inner rotor and a second internal gear type outer rotor that rotates in conjunction with the second inner rotor; a first drive shaft having one end connected to the first inner rotor and the other end connected to the carrier; one end connected to the second inner rotor and the other end connected to the ring gear; It has a cylindrical second drive shaft that is fitted rotatably relative to the shaft, and stops the operation of one of the first pump mechanism and the second pump mechanism to enable the operation of the other. A pump switching unit may be provided.

According to this, when the operation of the first pump mechanism is stopped by the pump switching unit while the electric motor is being driven, the first inner rotor and the first drive shaft of the first pump mechanism are connected to each other. In order to stop the rotation of the carrier, the rotational force of the ring gear is transmitted to the second inner rotor via the second drive shaft, allowing the fluid to be discharged by the second pump mechanism. On the other hand, when the operation of the second pump mechanism is stopped, the rotation of the ring gear, which is connected to the second inner rotor of the second pump mechanism via the second drive shaft, is stopped. It is transmitted to the first inner rotor via the first drive shaft, enabling the fluid to be discharged by the first pump mechanism. In addition, in this configuration, when switching between the first pump mechanism and the second pump mechanism, electric current is not wasted unlike in Patent Document 2.

In other words, in a planetary gear type transmission unit, the gear ratio is different between the drive mode in which the rotational force of the ring gear is extracted with the carrier constrained and the drive mode in which the rotational force of the carrier is extracted with the ring gear constrained. By selecting the mode, it is possible to drive the first pump mechanism and the second pump mechanism with different gear ratios.

As a configuration in addition to the above configuration, the pump switching section selects one of the first discharge section of the first pump mechanism and the second discharge section of the second pump mechanism to limit discharge of hydraulic oil. A channel selection valve may be provided.

According to this, by closing one of the discharge port of the first pump mechanism and the discharge port of the second pump mechanism with the passage selection valve, only one of the first pump mechanism and the second pump mechanism is driven. It becomes possible to discharge the fluid by

As a configuration added to the above configuration, an output gear provided in the inner space of the yoke so that the transmission unit rotates integrally with the motor rotor about the drive shaft, and the output gear meshes with the output gear. An input gear provided in the internal space may be provided, and rotational force of the input gear may be transmitted from the drive shaft to the pump section.

According to this, when the electric motor is driven, the rotational force of the output gear is transmitted to the input gear meshing with the output shaft, and the rotational force of the output gear is transmitted from the drive shaft to the pump section to drive the pump section. It becomes possible to In particular, in this configuration, since the output gear and the input gear are arranged in the internal space of the motor rotor, the size of the electric pump as a whole is not increased.

FIG. 4 is a cross-sectional view of the electric pump in a state where the first pump section is driven; FIG. 4 is a cross-sectional view of the electric pump in a state where the second pump section is driven; It is a hydraulic circuit diagram of an electric pump. It is sectional drawing of the electric pump of another embodiment (a). It is sectional drawing of the electric pump of another embodiment (b). It is sectional drawing of the electric pump of another embodiment (c). It is sectional drawing of the electric pump of another embodiment (d).

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
[Basic configuration]
As shown in FIGS. 1 and 2, a brushless type electric motor M, a planetary gear type transmission section G, a drive shaft S to which rotational force reduced by the transmission section G (an example of transmission) is transmitted, An internal gear type pump portion P is housed in a housing H, and a control unit C for controlling an electric motor M is provided in the housing H to form an electric pump A. As shown in FIG.

Although the electric pump A can be used in any posture, the positional relationship of each part will be described with the vertical direction determined as shown in FIGS.

1 and 2 show an electric pump A used as an oil pump for pumping hydraulic oil in a vehicle such as a passenger car. In this electric pump A, the driving force of the electric motor M is decelerated (an example of speed change) by the speed change portion G and transmitted to the pump portion P via the drive shaft S, whereby the suction port 6P formed at the end of the housing H is reduced. Hydraulic oil sucked from is delivered from the discharge port 7P.

The electric pump A is constructed such that a motor rotor 16 of an electric motor M is rotatable around a drive shaft core X. As shown in FIG. The electric pump A is configured so that the amount of hydraulic oil discharged from the pump portion P can be switched between two types. and a second drive shaft Sb that is rotatably fitted in the first drive shaft Sa. Further, the pump part P has a first pump mechanism Pa driven by the driving force of the first drive shaft Sa and a second pump mechanism Pb driven by the driving force of the second drive shaft Sb.

As shown in FIGS. 1 to 3, the first pump mechanism Pa is configured such that the diameter of the first outer rotor 32 of the first pump mechanism Pa is smaller than the diameter of the second outer rotor 34 of the second pump mechanism Pb. , the capacity of the first pump mechanism Pa is smaller than the capacity of the second pump mechanism Pb.

In particular, the electric pump A stops the operation of one of the first pump mechanism Pa and the second pump mechanism Pb to actuate the other, and transmits the driving force from the transmission unit G to the other to change the speed. It is configured such that the first drive shaft Sa and the second drive shaft Sb can be driven at a ratio. These configurations are detailed below.

〔housing〕
As shown in FIGS. 1 and 2, the housing H includes a first housing 1 made of resin that houses an electric motor M, a second housing 2 made of metal that houses a first pump mechanism Pa, and a second pump mechanism. A third metal housing 3 containing Pb, a fourth metal housing 4 arranged at the bottom, and a lid-like fifth housing arranged above the first housing 1 so as to cover the control unit C. 5 are laminated.

The first housing 1 accommodates an electric motor M, a transmission section G, and an electromagnetic switching valve V (an example of a pump switching section T). The field coil 15 of the electric motor M and the electromagnetic switching valve V are inserted into the first housing 1 during molding by a mold. The field coil 15 has a structure in which a coil wire is wound around a plurality of teeth of a stator core made of laminated electromagnetic steel plates, and is arranged in an annular region centered on the drive shaft core X. there is

The second housing 2 accommodates the first pump mechanism Pa and has a projecting portion 2a projecting into the inner space of the upper housing along the drive shaft center X. The projecting portion 2a is attached to the drive shaft. A shaft support hole through which the drive shaft S penetrates is formed coaxially with the core X. Thereby, the first drive shaft Sa of the drive shaft S is rotatably supported with respect to the shaft support hole.

The third housing 3 accommodates the second pump mechanism Pb. The fourth housing 4 has a suction passage 6 and a discharge passage 7 formed therein, and a suction port 6P connected to the suction passage 6 and a discharge port 7P connected to the discharge passage 7 are formed on the bottom surface. Further, the fourth housing 4 is internally provided with a channel selection valve 8 (an example of a pump switching section T).

The fifth housing 5 is arranged at a position to cover a recess formed in the upper portion of the first housing 1 and opening upward. A control unit C is configured by a control board 9 provided in the space covered by the fifth housing 5 . This control unit C controls the electric motor M and the electromagnetic switching valve V. As shown in FIG.

In other words, the control unit C controls the electric power control section that supplies electric power to the field coil 15 of the electric motor M, the rotation control section that controls the rotation speed (the number of rotations per unit time) of the motor rotor 16, and the electromagnetic switching valve V. and a valve control unit.

[Electric motor/transmission part]
The electric motor M includes a field coil 15 arranged in an annular region centered on the drive shaft core X, and a motor rotor 16 that rotates around the drive shaft core X by a magnetic field acting from the field coil 15. there is The motor rotor 16 is provided with a plurality of permanent magnets 16b on the outer periphery of a cylindrical yoke 16a made of a magnetic material such as iron. On the other hand, it is rotatably supported around the drive shaft center X via a roller bearing type bearing 17 .

The transmission portion G includes a sun gear 21 projecting downward coaxially with the drive shaft center X from the lower surface of a rotor plate 18 fixed to the upper end of the motor rotor 16, and an annular ring centered on the drive shaft center X. It comprises a ring gear 22 having internal teeth, a plurality of planetary gears 23 meshing with the sun gear 21 and the ring gear 22, and a pair of upper and lower carriers 25 supporting the spindles 24 of the plurality of planetary gears 23.

In particular, a sun gear 21, a ring gear 22, a plurality of planetary gears 23, and a pair of carriers 25, which constitute the transmission portion G, are accommodated in the internal space of the motor rotor 16 (the space inside the yoke 16a).

[Pump part]
As described above, the pump section P includes the first pump mechanism Pa and the second pump mechanism Pb. As shown in FIG. 3, the first pump mechanism Pa includes a first inner rotor 31 having a plurality of external teeth and a first inner rotor 31 having internal teeth whose number of teeth is one tooth larger than the number of external teeth of the first inner rotor 31 . and an outer rotor 32 . The second pump mechanism Pb includes a second inner rotor 33 having a plurality of external teeth, and a second outer rotor 34 having internal teeth whose number of teeth is one larger than that of the external teeth of the second inner rotor 33. .

The pump part P (the generic concept of the first pump mechanism Pa and the second pump mechanism Pb) includes an inner rotor (first inner rotor 31, second inner rotor 33) and an outer rotor (first outer rotor 32, second outer rotor 34). Negative pressure acts on the area where the space between the internal teeth and the external teeth expands with rotation, and positive pressure acts on the area where the space between the internal teeth and the external teeth shrinks with rotation. Therefore, the area where the negative pressure acts is communicated with the suction passage 6, and the area where the positive pressure acts is communicated with the discharge passage 7. As shown in FIG.

In particular, in the discharge path 7, the flow path selection valve 8 is arranged between the first discharge part of the first pump mechanism Pa and the discharge port 7P. A region intermediate to the selection valve 8 is referred to as a first discharge passage 7a. Further, the flow path selection valve 8 is arranged in the discharge path 7 between the second discharge part of the second pump mechanism Pb and the discharge port 7P. The region is called a second discharge passage 7b.

Note that the first discharge portion is a portion of the first pump mechanism Pa that discharges hydraulic oil as it operates, and the second discharge portion discharges hydraulic oil as it operates in the second pump mechanism Pb. It is a part.

[Drive structure/pump switching operation]
As shown in FIGS. 1 and 2, one end (upper end) of the first drive shaft Sa of the drive shaft S is connected to an end plate 26 that rotates integrally with the ring gear 22. is connected to the first inner rotor 31 of the first pump mechanism Pa.

One end (upper end) of the second drive shaft Sb of the drive shaft S is connected to the lower carrier 25 of the pair of carriers 25, and the other end (lower end) of the second drive shaft Sb is connected to the lower carrier 25 of the pair of carriers 25. ) is connected to the second inner rotor 33 of the second pump mechanism Pb.

The planetary gear type transmission unit G rotates the ring gear 22 by stopping the rotation of the carrier 25 while the sun gear 21 is rotating, and by stopping the rotation of the ring gear 22 while the sun gear 21 is rotating, the carrier 25 is It has the property of rotating.

By utilizing such properties, in the electric pump A, the rotation of the carrier 25 is stopped to take out driving force from the ring gear 22, and the rotation of the ring gear 22 is stopped to take out driving force from the carrier 25. It has a T.

The pump switching section T includes an electromagnetic switching valve V and a flow path selection valve 8 . As shown in FIGS. 1 and 2, it has a spool movably accommodated in a spool hole formed in the fourth housing 4. This spool has land portions 8a at both ends in the longitudinal direction. forming. A compression coil type spring 10 for applying pressure to one end of the flow path selection valve 8 is accommodated in the spool hole, and the other end of the flow path selection valve 8 applies pressure of hydraulic oil. A pressure chamber 11 is formed which can be acted upon.

Further, the flow path selection valve 8 is operated by the spool to select one of the first discharge path 7a through which the hydraulic fluid is delivered from the first pump mechanism Pa and the second discharge path 7b through which the hydraulic fluid is delivered from the second pump mechanism Pb. is selectively closed, and the lubricating oil from the other side can be controlled to be sent out from the discharge port 7P. Further, the second discharge passage 7b is provided with a check valve 12 which is opened and closed by the action of a ball to prevent backflow of hydraulic oil.

The channel selection valve 8 is configured to be switchable between a first selection position shown in FIG. 1 and a second selection position shown in FIG. At the first selection position, one land portion 8a closes the second discharge passage 7b and communicates the first discharge passage 7a with the discharge port 7P. Conversely, in the second selection position, the other land portion 8a closes the first discharge passage 7a and communicates the second discharge passage 7b with the discharge port 7P.

The electromagnetic switching valve V controls the flow of hydraulic fluid through a first control flow path 13 a supplied with hydraulic fluid from the discharge port 7</b>P and a second control flow path 13 b communicating with the pressure chamber 11 . The electromagnetic switching valve V reduces the pressure in the pressure chamber 11 without supplying hydraulic oil to the second control flow path 13b when the electromagnetic solenoid is not energized. As a result, the biasing force of the spring 10 sets the flow path selection valve 8 to the first selection position shown in FIG.

On the other hand, by energizing the electromagnetic solenoid, hydraulic oil from the first control flow path 13a is supplied to the second control flow path 13b, and pressure is applied to the pressure chamber 11 from the discharge port 7P. As a result, the passage selection valve 8 is set to the second selection position shown in FIG. 2 against the urging force of the spring 10 .

It should be noted that the pump switching portion T may be constructed so as to decrease the pressure in the pressure chamber 11 when the electromagnetic solenoid of the electromagnetic switching valve V is energized, and to increase the pressure in the pressure chamber 11 when the electromagnetic solenoid is not energized. good.

Although not shown in the drawings, the control unit C detects an oil temperature sensor (not shown) that detects the oil temperature of the hydraulic oil, and if the detected oil temperature is less than a set value, the control unit C controls the electromagnetic switching valve V to set the flow path selection valve 8 to the first selection position, and sets the flow path selection valve 8 to the second selection position when the detected oil temperature exceeds the set value. .

That is, when the oil temperature of the hydraulic oil is lower than the set value, the control unit C drives and rotates the electric motor M, and controls the electromagnetic solenoid of the electromagnetic switching valve V not to be energized. is lowered, and the biasing force of the spring 10 sets the passage selection valve 8 to the first selection position shown in FIG.

As a result, in the first selection position, the second inner rotor 33 is prevented from rotating because the second pump mechanism Pb cannot discharge hydraulic oil. Therefore, the transmission portion G is maintained in a state in which the carrier 25 is fixed, and the ring gear 22 rotates, so that the rotational force of the ring gear 22 is transmitted from the first drive shaft Sa to the first pump mechanism Pa. 1 pump mechanism Pa is driven, and hydraulic oil is sent out to the first discharge passage 7a. Further, when hydraulic fluid is supplied to the first discharge passage 7a in this way, the check valve 12 is opened by the pressure of the hydraulic fluid as shown in FIG.

On the other hand, when the oil temperature of the hydraulic oil exceeds the set value, the control of the control unit C drives the electric motor M to rotate and the electromagnetic solenoid of the electromagnetic switching valve V is energized. 11 pressure rises and the passage selection valve 8 is set to the second selection position shown in FIG.

As a result, the hydraulic oil cannot be discharged from the first pump mechanism Pa, so the rotation of the first inner rotor 31 is prevented. Therefore, the transmission portion G is maintained in a state where the ring gear 22 is fixed, and the carrier 25 rotates, so that the rotational force of the carrier 25 is transmitted from the second drive shaft Sb to the second pump mechanism Pb. The 2-pump mechanism Pb is driven, and hydraulic oil is sent out to the second discharge passage 7b. Further, when hydraulic oil is sent out to the second discharge passage 7b in this way, the pressure in the first discharge passage 7a decreases, so that the check valve 12 is closed as shown in FIG. Even if the hydraulic oil leaking from the valve 8 tries to flow in the direction of the first discharge passage 7a, the check valve 12 prevents the flow.

[Action and effect of the embodiment]
As described above, since the transmission portion G is accommodated inside the motor rotor 16 of the electric motor M, the driving force of the electric motor M can be reduced and transmitted to the pump portion P without increasing the size of the electric pump A. becomes possible. Further, since the transmission portion G is configured in a planetary gear type, the size of the entire electric pump A of the transmission portion G is not increased.

In the electric pump A, the yoke 16a that constitutes the motor rotor 16 of the electric motor M has a cylindrical portion that opens toward the pump portion P, and the cylindrical portion is supported by the bearing 17 on the projecting portion 2a. , realizes stable rotation of the motor rotor 16 .

Further, since the diameter of the second outer rotor 34 of the second pump mechanism Pb is larger than the diameter of the first outer rotor 32 of the first pump mechanism Pa, the frictional force acting during rotation acts on the first pump mechanism Pa. greater than the frictional force that

When the oil temperature of the hydraulic oil detected by the oil temperature sensor is below the set value, the viscosity of the hydraulic oil is high. For this reason, when the temperature of the hydraulic oil is lower than the set value, the control unit C controls the pump switching section T to drive the first pump mechanism Pa, thereby driving the second pump mechanism Pb. Hydraulic oil can be supplied by driving the electric motor M with a current smaller than the current required to do so.

On the other hand, when the oil temperature of the hydraulic oil exceeds the set value, the viscosity of the hydraulic oil is low (lower than the viscosity at high temperatures). For this reason, when the temperature of the hydraulic oil exceeds the set value, the control unit C controls the pump switching section T to drive the second pump mechanism Pb, thereby preventing the supply of a large current to the first pump. 2 pump mechanism Pb is driven to enable the supply of hydraulic oil.

In particular, when driving the second pump mechanism Pb, the second pump mechanism Pb is driven at the highest efficiency rotational speed (rotation speed per unit time), and the electric motor M is driven at the highest efficiency. It drives at various rotation speeds and realizes the supply of hydraulic oil with the highest efficiency.

In other words, the rotational speed at which the pump portion P supplies the working oil most efficiently differs from the rotational speed at which the electric motor M rotates most efficiently. For this reason, the electric pump A drives the second pump mechanism Pb at the highest efficiency rotational speed (rotational speed per unit time) when supplying hydraulic fluid at a set flow rate required for the vehicle. , the gear ratio in the transmission portion G (the gear ratio transmitted via the second drive shaft Sb) is set so as to drive the electric motor M at a rotational speed that provides the highest efficiency.

By setting the rotational speed in this manner, for example, compared to a configuration in which the rotation of the electric motor M is transmitted without changing the speed to rotate the pump portion P at high speed, it is possible to drive with improved quietness and efficiency. Since the electric motor M is effectively driven, the electric current is not wasted. Further, in order to drive the first pump mechanism Pa in a state where the electromagnetic solenoid of the electromagnetic switching valve V is not energized, for example, in a situation where a large amount of current is required in the vehicle, such as when starting the engine of the vehicle, the electromagnetic solenoid No current needs to be supplied.

[Another embodiment]
The present invention may be configured as follows other than the above-described embodiments (components having the same functions as those of the embodiments are given the same numbers and symbols as those of the embodiments).

The electric pump A is configured as in other embodiments (a) to (d). The configurations of the other embodiments (a) to (d) are respectively shown in FIGS. , and the configuration in which the transmission portion G is accommodated in the internal space of the motor rotor 16 of the electric motor M (the space inside the yoke 16a) is common to the embodiment, but the pump portion P is a single internal gear type , and the configuration of the transmission portion G is different from that of the embodiment.

In the other embodiments (a) to (d), the pump part P is accommodated in a hole-shaped part vertically penetrating the third housing 3, and is vertically sandwiched between the lower surface of the second housing 2 and the fourth housing 4. It is placed in a position where it can be A suction port 6</b>P and a discharge port 7</b>P are formed on the lower surface of the fourth housing 4 .

Although the electric pump A can be used in any posture, the positional relationship of each part will be described with the vertical direction determined as shown in FIGS. 4 to 7 also in these other embodiments.

(a) As shown in FIG. 4 , the electric pump A accommodates a planetary gear type transmission G in the inner space of the cylindrical yoke 16 a of the motor rotor 16 . The transmission portion G includes a sun gear 21, a ring gear 22, a planetary gear 23, and a pair of carriers 25 supported by a support shaft 24, as in the embodiment. The electric motor M has a yoke 16a whose lower end is rotatably supported by the protrusion 2a of the housing H through a bearing 17. As shown in FIG.

Further, the lower end of the ring gear 22 of the transmission portion G is fixed to the projecting portion 2a of the housing H in a fitted state, and the lower one of the pair of carriers 25 of the transmission portion G is connected to the drive shaft S. S is connected to the inner rotor of the pump section P.

In the electric pump A of this alternative embodiment (a), the driving force of the electric motor M is decelerated by the transmission portion G and transmitted to the drive shaft S, and the driving force of the drive shaft S is transmitted to the pump portion P. As a result, the pump portion P sucks hydraulic oil from the intake port 6P and delivers the hydraulic oil from the discharge port 7P.

In the electric pump A of this alternative embodiment (a), the reduction in size of the transmission section G is achieved by using planetary gears. The size reduction of the whole pump A is realized.

Further, the electric pump A of this alternative embodiment (a) drives the pump unit P at a rotational speed that provides the highest efficiency when supplying hydraulic oil at a set flow rate required for the vehicle, and at the same time, the electric motor M The transmission gear ratio of the transmission section G is set so as to drive at the rotational speed with the highest efficiency. By setting this gear ratio, wasteful consumption of energy during operation of the electric pump A is suppressed.

(b) As shown in FIG. 5 , the electric pump A accommodates a planetary gear-type transmission G in the inner space of the cylindrical yoke 16 a of the motor rotor 16 . The transmission unit G includes a ring gear 22 that rotates integrally with the yoke 16a on the inner circumference of the yoke 16a, a sun gear 21 on the upper end of the drive shaft S, and a plurality of planetary gears 23 that mesh with the ring gear 22 and the sun gear 21. there is The electric motor M has a yoke 16a whose lower end is rotatably supported by the protrusion 2a of the housing H through a bearing 17. As shown in FIG.

Furthermore, by supporting the support shafts 24 of the plurality of planetary gears 23 of the transmission section G on the projecting portion 2a of the second housing 2, the transmission section G is constructed in a speed increasing (an example of speed change) type. This transmission section G can be regarded as a planetary type in which the carrier 25 is fixed.

The electric pump A of this alternative embodiment (b) rotates the ring gear 22 with the driving force of the electric motor M, and this rotation is transmitted from the sun gear 21 to the drive shaft S via a plurality of planetary gears 23 to drive the drive shaft S. power is transmitted to the pump part P; The transmission section G of this alternative embodiment (b) is of a speed-increasing type, and as a result drives the pump section P at a higher speed than the electric motor M rotation speed (the number of rotations per unit time).

(c) As shown in FIG. 6, the electric pump A has a cylindrical yoke 16a of the motor rotor 16 which is rotatable around the drive shaft X, and the lower end of the yoke 16a protrudes from the housing H through a bearing 17. It is rotatably supported by the portion 2a. The transmission portion G is accommodated in the internal space of the yoke 16a.

In the electric pump A of this alternative embodiment (c), the transmission portion G protrudes downward from a pinion gear 41 (an example of an output gear) that rotates integrally with a rotor plate 18 fixed to the upper end of a motor rotor 16. Be ready with attitude. Further, the transmission portion G has a cylindrical gear 42 (an example of an input gear) formed with internal teeth meshing with the pinion gear 41 at the upper end of the drive shaft S, and transmits the driving force of the drive shaft S to the pump portion P.

The transmission portion G is of a reduction type in which the number of teeth of the cylindrical gear 42 is larger than that of the pinion gear 41 . The drive shaft S is rotatably supported by the projecting portion 2a of the housing H around a driven shaft Y parallel to the drive shaft X. As shown in FIG. Therefore, the driving force of the electric motor M is decelerated (speed-changed) by the transmission portion G, and transmitted from the drive shaft S to the pump portion P to drive the pump portion P. send out from

In this alternative embodiment (c), the miniaturization of the electric pump A is achieved by housing the speed changing portion G in the internal space of the motor rotor 16 . Further, the electric pump A of this alternative embodiment (c) drives the pump unit P at a rotational speed that provides the highest efficiency when supplying hydraulic oil at a set flow rate required for the vehicle, and at the same time, the electric motor M The transmission gear ratio of the transmission section G is set so as to drive at the rotational speed with the highest efficiency. By setting this gear ratio, wasteful consumption of energy during operation of the electric pump A is reduced.

(d) As shown in FIG. 7, the electric pump A has a cylindrical yoke 16a of the motor rotor 16 which is rotatably arranged around the drive shaft core X, and the lower end of the yoke 16a protrudes from the housing H through a bearing 17. It is rotatably supported by the portion 2a. The transmission portion G is accommodated in the internal space of the yoke 16a.

In the electric pump A of this alternative embodiment (d), the transmission portion G comprises an internal tooth type drive gear portion 44 formed on the inner circumference of the yoke 16a of the motor rotor 16, and the internal tooth type drive gear portion 44. 44 and an externally toothed driven gear 45 that meshes with the gear 44 . The driven gear 45 is provided at the upper end of the drive shaft S, and the drive force from the drive shaft S is transmitted to the inner rotor of the pump portion P. As shown in FIG.

The transmission portion G is configured as a speed increasing type in which the number of teeth of the internal tooth type drive gear portion 44 is larger than the number of teeth of the driven gear 45 . The drive shaft S is rotatably supported by the projecting portion 2a of the housing H around a driven shaft Y parallel to the drive shaft X. As shown in FIG. Therefore, the driving force of the electric motor M is accelerated (shifted) by the transmission portion G and transmitted from the drive shaft S to the pump portion P to drive the pump portion P. Send out from 7P.

In this alternative embodiment (d), the miniaturization of the electric pump A is achieved by housing the speed changing portion G in the internal space of the motor rotor 16 . Further, the transmission portion G of the electric pump A of this alternative embodiment (d) is of a speed-increasing type, and as a result, the pump portion P is driven at a higher speed than the rotational speed of the electric motor M (the number of revolutions per unit time). .

(e) The speed change portion G is not limited to the speed reduction structure shown in the embodiment or another embodiment, and may be one that uses a plurality of gears for speed change. Even with the transmission portion G having such a configuration, the size of the electric pump A can be reduced by accommodating it in the internal space of the motor rotor 16 .

(f) Two pump mechanisms are used as in the embodiment, and the flow path selection valve 8 of the embodiment is used without the electromagnetic switching valve V as the pump switching unit T for selecting operation and stop of the two pump mechanisms. Configured as an electromagnetic actuation type operated by an electromagnetic solenoid. By constructing in this way, the number of parts can be reduced and miniaturization is also possible.

INDUSTRIAL APPLICABILITY The present invention can be used for electric pumps.

2a Protruding portion 6P Suction port 7P Discharge port 8 Flow path selection valve (pump switching portion)
15 Field coil 16 Motor rotor 16a Yoke 16b Permanent magnet 17 Bearing 21 Sun gear 22 Ring gear 23 Planetary gear 25 Carrier 31 First inner rotor 32 First outer rotor 33 Second inner rotor 34 Second outer rotor 41 Pinion gear (output gear)
42 cylindrical gear (input gear)
G Transmission portion H Housing M Electric motor P Pump portion Pa First pump mechanism Pb Second pump mechanism S Drive shaft Sa First drive shaft Sb Second drive shaft T Pump switching portion V Electromagnetic switching valve (pump switching portion)
X drive shaft center

Claims (6)

an electric motor having a field coil arranged in an annular region centered on a drive shaft, and a motor rotor rotatably supported around the drive shaft and rotated by the action of the magnetic field of the field coil;
a transmission unit for transmitting the speed of rotation of the motor rotor to a drive shaft;
a pump unit driven by the driving force of the drive shaft;
a housing that accommodates each of the electric motor, the transmission unit, the drive shaft, and the pump unit;
An electric pump, wherein the motor rotor includes a permanent magnet on the outer peripheral side of a cylindrical yoke centered on the drive shaft, and the speed changer is accommodated in an inner space of the yoke. the housing has a projecting portion projecting in the direction of the transmission portion inside the housing so as to support the drive shaft in a penetrating state;
2. The electric pump according to claim 1, wherein a bearing that rotatably supports said motor rotor is supported in contact with said projecting portion. The transmission unit includes a sun gear, a ring gear arranged in a region surrounding the sun gear, and a plurality of planetary gears meshing with the sun gear and the ring gear. 3. The electric pump according to claim 1 or 2, wherein the electric pump is configured as a planetary gear for transmission to the shaft. The transmission unit includes a sun gear, a ring gear arranged in a region surrounding the sun gear, a plurality of planetary gears meshing with the sun gear and the ring gear, and a carrier supporting the plurality of planetary gears. It is configured as a planetary gear type that shifts the transmitted driving force and transmits it to the drive shaft,
The pump unit comprises an internal gear type first pump mechanism having a first inner rotor and a first outer rotor that rotates in conjunction with the first inner rotor, and a second inner rotor and an internal gear that rotates in conjunction with the second inner rotor. a second pump mechanism having a tangential gear type second outer rotor;
The drive shaft comprises: a first drive shaft having one end connected to the first inner rotor and the other end connected to the carrier; one end connected to the second inner rotor and the other end connected to the ring gear; a cylindrical second drive shaft that is rotatably fitted relative to the first drive shaft;
3. The electric pump according to claim 2, further comprising a pump switching unit that enables the operation of one of the first pump mechanism and the second pump mechanism by stopping the operation of the other. The pump switching section includes a flow path selection valve that selects one of a first discharge section of the first pump mechanism and a second discharge section of the second pump mechanism to limit discharge of hydraulic oil. The electric pump according to claim 4. The transmission unit includes an output gear provided in the inner space of the yoke so as to rotate integrally with the motor rotor about the drive shaft, and an input gear provided in the inner space so as to mesh with the output gear. and
3. The electric pump according to claim 1, wherein the rotational force of said input gear is transmitted from said drive shaft to said pump portion.

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