JP4869381B2 - Fuel supply device - Google Patents

Description

  The present invention relates to an electric motor and a fuel supply device that supplies fuel pressurized by the operation of a pump device driven by the electric motor.

  Conventionally, an electric motor having an electric motor chamber inside the electric motor housing, and a pump device having a pump device chamber formed in communication with the electric motor chamber inside the pump device housing including a suction port and a discharge port, the electric motor A fuel supply device is known in which the fuel flowing in from the suction port of the pump device housing through the pump is discharged from the discharge port through the pump device chamber (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2008-157055 (FIG. 1)

However, in the fuel supply device configured as described above, it is possible that a part of the fuel in the pump device chamber that has flowed in from the suction port flows into the motor chamber via the bearing and immerses the stator.
As a result, the temperature of the fuel rises due to the heat from the stator, and vapor is generated. This vapor causes vapor biting (vapor lock) in the pump device, resulting in a decrease in fuel discharge. There was a problem such as.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to obtain a fuel supply device that is unlikely to cause vapor lock in a pump device.

A fuel supply device according to the present invention includes a motor having a motor chamber inside a motor housing, and a pump having a pump device chamber formed in communication with the motor chamber inside a pump device housing including a suction port and a discharge port. And a partition body provided between the pump device and the electric motor, and the fuel that has flowed from the suction port of the pump device housing by the driving of the electric motor passes through the pump device chamber and is In the fuel supply device discharged from the discharge port, the partition body is fixed to the electric motor housing and generates a rotating magnetic field, and is provided inside the stator and rotates as the rotating magnetic field rotates. is provided between the rotor, have a cylindrical portion to which the fuel in the pump device chamber is blocked from reaching the stator, the pump unit is set to the pump device chamber A cylinder block having a plurality of cylinders provided, and a plunger which forms a pump chamber of variable volume in the cylinder and sliding in this cylinder,
With the rotation of the rotary swash plate fixed to the tip of the drive shaft of the rotor and inclined with respect to the axis of the drive shaft, the plunger whose tip surface abuts on the outer peripheral surface of the rotary swash plate moves forward and backward. The volume in the cylinder changes, and the partition body has a large diameter portion having a flange portion sandwiched between the electric motor housing and the pump device housing, and the stator and the rotor connected to the large diameter portion. And a bearing that rotatably supports the drive shaft is fitted to the opening end of the cylindrical portion on the rotating swash plate side .

  According to the fuel supply device of the present invention, the partition wall having the cylindrical portion that blocks the fuel in the pump device chamber from reaching the stator between the electric motor and the pump device and between the stator and the rotor. Since the body is provided, the fuel does not reach the stator, and there is an effect that vapor lock in the pump device is hardly generated.

1 is a configuration diagram illustrating a fuel supply system to which a fuel supply device according to a first embodiment of the present invention is applied. FIG. It is a sectional side view which shows the fuel supply apparatus of FIG. It is a figure which shows an electric motor housing among the arrow cross sections along the III-III line of the fuel supply apparatus of FIG. In the fuel supply apparatus of FIG. 1, it is a figure which shows the relationship between the elapsed time in the presence or absence of a partition body, and fuel temperature. It is a figure which shows the saturated vapor pressure characteristic of a fuel. It is a sectional side view which shows the fuel supply apparatus of Embodiment 2 of this invention. It is a front view which shows the fuel supply apparatus of Embodiment 3 of this invention.

  Hereinafter, the fuel supply device according to each embodiment of the present invention will be described with reference to the drawings. In each embodiment, the same or equivalent members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a configuration diagram showing a fuel supply system to which a fuel supply apparatus according to Embodiment 1 of the present invention is applied.
This fuel supply system includes a fuel tank 1, a fuel supply device 3 according to Embodiment 1 connected to the fuel tank 1 via a fuel supply pipe 2, and a high-pressure fuel pipe 4 connected to the fuel supply device 3. The fuel injection device 5 connected via the high pressure fuel pipe 4, the return pipe 6 branched from the high pressure fuel pipe 4 and connected to the fuel tank 1, the pressure adjusting device 7 provided in the return pipe 6, the fuel supply device 3, and the fuel injection And a control unit 8 electrically connected to the device 5.

In this fuel supply system, the fuel supply device 3 is driven by a drive signal from the control unit 8, and the fuel in the fuel tank 1 is supplied to the fuel supply device 3 through the filter 9 and the fuel supply pipe 2. The fuel pressurized by the fuel supply device 3 is adjusted to a predetermined pressure by the pressure adjustment device 7 and supplied to the fuel injection device 5 through the high-pressure fuel pipe 4.
In the fuel injection device 5, the fuel injection timing and the fuel injection amount are controlled by the drive signal from the control unit 8 based on the engine speed, the load, etc., and the fuel is injected into the intake pipe (not shown). The

FIG. 2 is a side sectional view of the fuel supply device 3, and includes an electric motor 10, a pump device 11 driven by the electric motor 10, and a partition body 38 provided between the electric motor 10 and the pump device 11. ing.
The electric motor 10 includes an electric motor housing 12 having an electric motor chamber A therein, a ring-shaped stator 14 embedded in a cylindrical wall 13 of the electric motor housing 12, and a bearing 16 on the central axis of the electric motor housing 12. A rotor 18 having a permanent magnet fixed to a drive shaft 15 rotatably supported by 17, a rotary swash plate 19 fixed to an end of the drive shaft 15 on the pump device 11 side, and the stator 14 are electrically connected. And a connector 21 having a terminal 20 exposed from the motor housing 12.

  The pump device 11 includes a pump device housing 22 having a pump device chamber B therein, a cylinder 23 provided in the pump device housing 22 and formed in plural at equal intervals in the circumferential direction, and a suction communicating with the cylinder 23. A cylinder block 24 having a passage 28, a plunger 25 that slides in the cylinder 23 to form a variable volume pump chamber, a suction valve 27 provided in each suction passage 28, and a suction valve 27 And a spring 46 biased toward the cylinder block 24.

  The pump device housing 22 includes a discharge passage 30 communicating with each cylinder 23, a discharge port 31 communicating with the discharge passage 30, and a suction port 32 communicating with the pump device chamber B and protruding vertically upward. A discharge valve 29 urged toward the cylinder 23 by a spring 33 is provided at the end of the discharge passage 30. The discharge valve 29 closes the hole 37 of the plate 36 by the elastic force of the spring 33. A spring 35 that presses the rotary swash plate 19 via the plunger 25 is provided between the cylinder block 24 and a spring stopper 34 attached to the plunger 25.

The partition body 38 has a large diameter portion 45 having a flange portion 41 sandwiched between the electric motor housing 12 and the pump device housing 22, and a bottomed portion that is connected to the large diameter portion 45 and partitions the stator 14 and the rotor 18. It has a cylindrical cylindrical portion 42 and is formed by injection molding.
The large-diameter portion 45 of the partition wall 38 that sandwiches the ring 47 in cooperation with the cylinder block 24 is a first portion that is fitted to the flange portion 41 and the inner wall surface of the edge of the pump device housing 22 via the O-ring 43. And a second fitting portion 40 fitted to the inner wall surface of the edge portion of the motor housing 12.
The partition wall 38 has the first fitting portion 39 fitted to the pump device housing 22 and the second fitting portion 40 fitted to the motor housing 12 so that the cylindrical portion 42 is inside the stator 14. Without contacting the wall surface and the outer peripheral surface of the rotor 18, the axis of the partition wall 38 and the axis of the drive shaft 15 are arranged in alignment.
As shown in FIG. 3, a labyrinth-shaped communication groove 44 is formed in the motor housing 12 where the large-diameter portion 45 of the partition wall 38 is in surface contact. A gap G between the outer peripheral wall surface of the cylindrical portion 42 and the inner peripheral wall surface of the stator 14 communicates with the outside air through a communication groove 44 directed downward.
The bearing 16 having an inner ring fixed to the drive shaft 15 has an outer ring fitted to the partition wall 38, supports the drive shaft 15 in a rotatable manner, and counteracts the drive shaft 15 due to the elastic force of the spring 35. The cylinder block 24 side (opposite side of the cylinder block 24) is supported against an axial load. Since the bearing 16 supports the load in the axial direction of the drive shaft 15, the bearing 17 provided at the bottom of the partition wall body 38 may support the load in the radial direction.
The drive shaft 15 may be rotatably supported only by the bearing 16 without providing the bearing 17.

In the fuel supply device 3 having the above-described configuration, a rotating magnetic field is generated in the stator 14 by flowing an electric current from the terminal 20, and the rotor 18 rotates in accordance with the rotating magnetic field. As the drive shaft 15 of the rotor 18 rotates , the rotary swash plate 19 also rotates.
As the rotary swash plate 19 rotates, the plunger 25 whose tip surface comes into contact with the outer peripheral surface of the rotary swash plate 19 sequentially reciprocates in the cylinder 23 in the order of the rotation direction, and from the suction port 32 to the pump device chamber B. The fuel flowing into the fuel is pressurized by the fuel supply device 3, flows into the high-pressure fuel pipe 4 through the discharge port 31, and is injected into the intake pipe from the fuel injection device 5.
That is, as the plunger 25 moves to the electric motor 10 side, the volume in the cylinder 23 increases. With this increase, the suction valve 27 moves to the discharge port 31 side against the elastic force of the spring 46 and sucks. The passage 28 is opened, and the fuel flows into the cylinder 23 through the suction passage 28 and the suction valve 27. The fuel in the cylinder 23 is pressurized in accordance with the movement of the plunger 25 on the side opposite to the electric motor 10 (the side opposite to the electric motor 10), and the discharge valve 29 opens the hole 37 of the plate 36 against the elastic force of the spring 33. The fuel flows to the discharge port 31 through the hole 37, the discharge valve 29, and the discharge passage 30.

According to the fuel supply device 3 configured as described above, the partition wall 38 is provided between the stator 14 and the rotor 18 that is provided inside the stator 14 and rotates in accordance with the rotation of the rotating magnetic field. Since the bottomed cylindrical tube portion 42 that blocks the fuel in the apparatus chamber B from reaching the stator 14 is provided, an air layer having low thermal conductivity is interposed between the stator 14 and the tube portion 42.
Therefore, the heat generated in the stator 14 is difficult to be transmitted to the fuel in the electric motor chamber A through the cylindrical portion 42, and the temperature rise of the fuel can be suppressed.

FIG. 4 is a diagram showing the relationship between the elapsed time of operation with and without the partition wall 38 of the fuel supply device 3 and the fuel temperature, and is data obtained by the inventor through experiments.
Here, the fuel temperature indicates the fuel temperature in the pump device chamber B in a state where the engine is left idle (so-called hot soak), which is a condition in which the fuel temperature tends to reach a high temperature as a representative example.
As can be seen from this figure, after a certain period of time, the fuel has decreased by about 4 ° C. as compared to the conventional fuel supply device without the partition wall 38.
Further, although the fuel pressure in the pump device chamber B communicating with the outside air is approximately the same as the atmospheric pressure , as can be seen from the saturation vapor pressure characteristic diagram of the fuel shown in FIG. Therefore, the vapor lock in the pump device 11 hardly occurs.

Further, the partition body 38 is connected to the large-diameter portion 45 and separates the stator 14 and the rotor 18 from the large-diameter portion 45 having the flange portion 41 sandwiched between the electric motor housing 12 and the pump device housing 22. The bearing 16 which rotatably supports the drive shaft 15 is fitted to the opening end of the cylindrical portion 42 on the rotary swash plate 19 side.
Accordingly, since the bearing 16 is fitted to the large-diameter portion 45, the load in the axial direction through the plunger 25, the rotary swash plate 19 and the drive shaft 15 due to the elastic force of the spring 35 and the force applied to the plunger 25 is reduced. Most of them are supported by the bearing 16, so that the load on the cylindrical portion 42 is reduced and the thickness of the cylindrical portion 42 can be reduced.
For this reason, although the cylindrical portion 42 is interposed between the stator 14 and the rotor 18, there is no need to increase the gap between the stator 14 and the rotor 18, and the partition wall 38 is provided. And the fall of the performance of the electric motor 10 can be suppressed. As a result, an increase in current flowing through the electric motor 10 can be suppressed, and an increase in fuel temperature can be suppressed.

  The large-diameter portion 45 is formed by fitting the first fitting portion 39 to the opening end portion of the pump device housing 22 and fitting the second fitting portion 40 to the opening end portion of the motor housing 12. The axial center of the partition wall 38 and the axial center of the drive shaft 15 are arranged so that the cylindrical portion 42 does not contact the inner wall surface of the stator 14 and the outer peripheral surface of the rotor 18.

A gap G is formed between the outer peripheral surface of the cylindrical portion 42 and the inner peripheral surface of the stator 14, and the gap G is in contact with the large diameter portion 45 and the large diameter portion 45. because communication with the communication groove 44 formed between the heat generated in the stator 14 is released to the outside air through the communicating groove 44.
Moreover, the pressure rise accompanying the temperature rise in the gap G can be prevented.
Furthermore, since the air in the gap G is not sealed when the partition wall 38 is assembled to the electric motor 10, the assembling work can be performed smoothly.
Further, since the communication groove 44 is directed downward and communicates with the outside air, for example, dew condensation generated on the inner wall of the stator 14 is smoothly discharged to the outside through the communication groove 44.

Since the cylindrical portion 42 of the partition wall 38 is disposed in the electric motor chamber A before the fuel is pressurized, no large pressure is applied to the cylindrical portion 42 and the strength is weaker than that of metal. It can be formed of resin.
Further, since the partition body 38 is formed of resin, the partition body 38 having a complicated shape including the large diameter portion 45 having the first fitting portion 39 and the second fitting portion 40 and the cylindrical portion 42. Can be manufactured easily and at low cost by injection molding.
In addition, since the partition wall 38 is nonmagnetic, it does not adversely affect the rotating magnetic field generated in the stator 14.

Embodiment 2. FIG.
6 is a side sectional view showing a fuel supply device 3 according to Embodiment 2 of the present invention.
In this embodiment, the partition wall 38 </ b> A has a hole formed at the bottom of the cylinder portion 42 </ b> A, and a cap 50 is fitted into the hole via an O-ring 52. A bearing member 51 is interposed between the cap 50 and the end surface of the drive shaft 15.
Other configurations are the same as those of the first embodiment.

According to this embodiment, the bearing member 51 is interposed between the cap 50 and the end surface of the drive shaft 15, and the partition wall 38 </ b> A and the bearing member 51 are configured as separate members. Since the load in the axial direction through the plunger 25, the rotary swash plate 19 and the drive shaft 15 due to the elastic force of this and the force applied to the plunger 25 is not applied to the cylinder part 42A, the wall of the cylinder part 42A of the partition wall 38A The thickness can be reduced, and a decrease in the performance of the electric motor 10 can be suppressed.
Other functions and effects are the same as those of the first embodiment.

Embodiment 3 FIG.
FIG. 7 is a front view showing a fuel supply device 3 according to Embodiment 3 of the present invention.
In this embodiment, fins 53 are formed on the outer peripheral surface of the motor housing 12.
Other configurations are the same as those of the first embodiment.

According to this embodiment, since the fins 53 are formed on the outer peripheral surface of the motor housing 12, the surface area of the motor housing 12 can be increased, the heat dissipation performance of the motor 10 is improved, and the performance of the motor 10 is improved. improves.
Other functions and effects are the same as those of the first embodiment.

In the above first to third embodiments, the pump device 11 having the rotary swash plate 19 has been described. However, the present invention can also be applied to a pump device that does not use the rotary swash plate 19 for reciprocating the plunger 25. it can.
Further, although the communication groove 44 is formed on the electric motor housing 12 side, it may be formed on the large diameter portion 45 side of the partition wall 38.

  DESCRIPTION OF SYMBOLS 10 Electric motor, 11 Pump apparatus, 12 Motor housing, 14 Stator, 15 Drive shaft, 16 Bearing, 18 Rotor, 19 Rotary swash plate, 22 Pump apparatus housing, 23 Cylinder, 24 Cylinder block, 25 Plunger, 38, 38A Partition Body, 39 first fitting portion, 40 second fitting portion, 41 flange portion, 42, 42A tube portion, 44 communicating groove, 45 large diameter portion, 51 bearing member, 53 fin, G gap.

Claims (7)

An electric motor having an electric motor chamber inside the electric motor housing;
A pump device having a pump device chamber formed in communication with the motor chamber inside a pump device housing including a suction port and a discharge port;
A partition provided between the pump device and the electric motor,
The fuel that flows in from the suction port of the pump device housing by driving the electric motor is a fuel supply device that is discharged from the discharge port through the pump device chamber,
The partition body is provided between a stator that is fixed to the electric motor housing and generates a rotating magnetic field, and a rotor that is provided inside the stator and rotates in accordance with the rotation of the rotating magnetic field. the fuel have a cylindrical portion for blocking from reaching the stator of,
The pump device includes a cylinder block provided in the pump device chamber and having a plurality of cylinders, and a plunger that slides in the cylinder to form a variable volume pump chamber in the cylinder,
With the rotation of the rotary swash plate fixed to the tip of the drive shaft of the rotor and inclined with respect to the axis of the drive shaft, the plunger whose tip surface abuts on the outer peripheral surface of the rotary swash plate moves forward and backward. The volume in the cylinder changes,
The partition body includes a large-diameter portion having a flange portion sandwiched between the electric motor housing and the pump device housing, and a cylindrical portion that is connected to the large-diameter portion and divides the stator and the rotor. And
A fuel supply device , wherein a bearing that rotatably supports the drive shaft is fitted to an opening end portion of the cylindrical portion on the rotary swash plate side . On the opposite side of the swash plate of the cylindrical portion, according to claim 1, characterized in that the bearing member for supporting a load in the axial direction from the end face in contact with the drive shaft of the drive shaft are provided Fuel supply system. The large diameter portion has a first fitting portion fitted to the opening end portion of the pump device housing, and a second fitting portion fitted to the opening end portion of the electric motor housing. the fuel supply apparatus according to claim 1 or 2, characterized in that there. A gap is formed between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the stator, and this gap is between the large diameter portion and the motor housing that is in surface contact with the large diameter portion. The fuel supply device according to any one of claims 1 to 3 , wherein the fuel supply device communicates with outside air through a communication groove formed in the outer periphery. The fuel supply device according to claim 4 , wherein the communication groove is directed downward and communicates with outside air. The fuel supply device according to any one of claim 1 to 5, characterized in that the fins are formed on the outer circumferential surface of the motor housing. The partition body, the fuel supply apparatus according to any one of claim 1 to 6, characterized in that it is made of a non-magnetic resin.

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