JPH0756270B2 - Electric pump - Google Patents

Description

The present invention relates to a commutator fixed to the outer periphery of a rotary shaft, a brush slidingly contacted with the commutator and connected to a power source, and a commutator. An armature fixed to the outer periphery of the rotating shaft,
The present invention relates to an electric pump including: a pair of magnets arranged on the outer circumference of an armature with a gap; and an electric motor; a liquid pump that sucks and discharges liquid by the output of a rotating shaft of the electric motor; In, it is used as a fuel pump for supplying fuel to the engine.

[Conventional technology]

The electric pump includes an electric motor and a liquid pump driven by the electric motor.

The electric motor includes a stator including a field magnet such as a yoke and a permanent magnet, a current collecting portion such as a brush and a brush holder, a support portion such as a bracket and a bearing, and an armature inserted in a slot of an armature core. , A commutator, a rotating shaft, and a rotor.

On the other hand, the liquid pump includes a roller vane type, an impeller turbine type, a multi-stage turbine type, a combination of roller vanes and a turbine, and the like.

When using such an electric pump as a fuel pump of a fuel injection device, it is necessary to maintain the pressure of the fuel supplied from the electric pump to the injector at a substantially constant pressure (for example, about 2.5 kg / cm ² ). It is necessary to release this pressure and the electric pump may be provided with a relief valve. In this relief valve, a valve seat is provided in a fuel return passage that connects a fuel discharge passage of an electric pump and a fuel tank, and an on-off valve backed up by a spring is arranged facing the valve seat.

When the discharge pressure of the fuel discharged by the electric pump rises above a predetermined constant pressure, the on-off valve opens the valve seat against the spring force of the spring by the increased fuel pressure and returns the fuel to the fuel. By returning the fuel to the fuel tank via the passage, the pressure of the fuel flowing in the fuel discharge passage can be maintained at a predetermined pressure state by releasing the fuel.
(For example, such a conventional electric pump is disclosed in Japanese Patent Laid-Open No. 60-79193.) [Problems to be Solved by the Invention] According to such a conventional electric pump, the following points are desired to be solved.

The relief valve must have good closure between the valve seat and the on-off valve. For this reason, it is necessary to improve the processing accuracy of the contact part between the valve seat and the on-off valve, which increases the manufacturing cost of the product. Be invited.

Since the fuel return passage is provided, it is necessary to consider the piping when the fuel return passage is mounted on the vehicle, and the degree of freedom in design for mounting on the engine is suppressed.

[Means for solving the problem]

An electric pump according to the present invention aims to obtain the electric pump which is inexpensive to manufacture and has a high degree of freedom in mounting on an engine. To achieve the above object, a commutator fixed to the outer periphery of a rotary shaft is provided. A brush that is in sliding contact with the commutator and that is connected to the power supply; an armature that is connected to the commutator and that is fixed to the outer circumference of the rotating shaft; An electric motor consisting of;
In an electric pump consisting of a liquid pump that sucks and discharges liquid by the output of the rotating shaft of an electric motor; in an electric pump, an air chamber whose housing communicates with the atmosphere, and a pressure chamber into which the discharge pressure of the liquid discharged from the liquid pump is introduced. A partition member for partitioning the partition member and the brush; a connecting member for mechanically connecting the partition member and the brush; a spring that is contracted in the atmosphere chamber and elastically presses the brush to the commutator through the partition member and the connecting member. And a pressure response device comprising: When the pressure of the liquid discharged from the liquid pump rises above a certain pressure, the partition facing the pressure chamber moves to the atmosphere chamber side by receiving the rising pressure. The contact between the brush and the commutator is brought into a non-contact state, and the current flowing from the brush toward the commutator is temporarily cut off.

[Action]

When the pressure of the liquid discharged by the liquid pump reaches a certain pressure or more, the pressure responding device operates due to the increased liquid pressure, and the brush separates from the commutator and becomes in a non-contact state.

According to this, the rotation of the electric motor is stopped, the liquid is not discharged from the liquid pump, and the liquid pump is stopped. Therefore, the liquid pressure in the fuel discharge passage that has risen above a certain pressure decreases, and the desired liquid discharge pressure can be maintained.

〔Example〕

An embodiment of the electric pump according to the present invention will be described below with reference to FIG. The electric pump P includes an electric motor A, a liquid pump B, and a pressure response device C.

The electric motor A will be described.

Reference numeral 1 denotes a cylindrical housing having both ends opened, and a rotary shaft 2 is arranged on a longitudinal center of the housing 1. One end of the rotary shaft 2 covers a first opening of the housing 1 by a first lid. The body 3 is rotatably supported via a bearing 4, and the other end of the rotary shaft 2 is freely rotatable via a bearing 6 to a pump body 5 of a liquid pump P, which will be described later, disposed in the other opening of the housing 1. Supported by. A commutator 7 is fixedly arranged on the outer periphery of the rotary shaft 2 concentrically with the rotary shaft 2, and the commutator 7 is further provided.
An armature 8 is fixedly arranged concentrically with the rotating shaft 2 on the outer periphery of the rotating shaft 2 on the side of, and the commutator 7 and the armature 8 are electrically connected.

Further, a pair of semi-cylindrical magnets 9A, 9B corresponding to the outer circumference of the armature 8 are fixedly arranged on the inner wall of the housing 1, and a minute gap is formed between the magnets 9A, 9B and the armature 8. .

10A and 10B are brush holding holes provided so as to face each other with the commutator 7 sandwiched between them. In the brush holding holes 10A and 10B, the outer peripheral surface of the commutator 7 is brought into contact, non-contact, and direction ( First
The brushes 11A, 11B are arranged so as to be movable in the X-Y direction in the drawing, and the inner end surfaces of the brushes 11A, 11B are in sliding contact with the outer peripheral surface of the commutator 7.

That is, the brush 11A on the lower side in FIG. 1 is elastically pressed upward in FIG. 1 by the spring force of the spring 12 and comes into contact with the commutator 7. The pressing of the upper brush 11B in FIG. 1 against the outer peripheral surface of the commutator 7 will be described later.

Then, the brushes 11A and 11B are connected to a power source (not shown). Further, 40 is a liquid discharge passage formed in the first lid body 3, one end of which is opened in the housing 1 and the other end is connected to a consumption portion such as an injector.

Next, the liquid pump B will be described.

The liquid pump B has a rotor housing recess 12 formed in the pump body 5 that covers the opening on the other side of the housing 1, and a second opening that covers the rotor housing recess 12 of the pump body 5 and opens outward. The inner rotor 15 includes a rotor housing chamber 14 formed by a lid 13, an inner rotor 15 mechanically connected to the rotating shaft 2, and an outer rotor 16 whose inner circumference is joined to the outer circumference of the inner rotor 15.
Liquid suction passage 18A formed in the second lid 13 in the pump chamber 17 formed by the outer periphery of the outer rotor 16 and the inner periphery of the outer rotor 16.
Then, the liquid discharge passage 18B formed in the pump body 5 opens. The liquid suction passage 18A is connected to a liquid storage tank (not shown), and the liquid discharge passage 18B opens into the inside 1A of the housing 1. (Note that the liquid pump B itself is known.) Next, the pressure response device C will be described.

Reference numeral 20 denotes a housing, and the housing 20 divides an atmosphere chamber 22 upward in FIG. 1 by a partition 21 such as a diaphragm.
A pressure chamber 23 is sectioned and formed below. The atmosphere chamber 22 is communicated with the atmosphere through an air introduction passage 24, and the pressure chamber 23 is formed as a pressure introduction passage.
It communicates with the inside 1A of the housing 1 via 25. on the other hand,
A connecting member 26 is integrally attached to the partition body 21, and a lower end portion 23A of the connecting member 26 has the brush 11 located in the brush holding hole 10B.
Screwed to B. In addition, one end of the compartment 2
A spring 28 arranged on the upper surface of 1 and the other end of which is arranged on the end surface of an adjuster 27 screwed to the housing 20 above the atmosphere chamber 22 is compressed.

The partition body 21 including the connecting member 26 is elastically pressed toward the pressure chamber 23 side (downward in FIG. 1) by the spring 28, whereby the inner end surface of the brush 11B moves toward the commutator 7. The outer peripheral surface is elastically pressed to make sliding contact.

Next, the operation will be described.

When the electric pump P is not driven, the brush 11A is in contact with the outer peripheral surface of the commutator 7 by the spring force of the spring 12, and the brush 11B applies the spring force of the spring 28 of the pressure responding device C to the partition body 21 and the connecting member. Since it is received via 26, it is in contact with the outer peripheral surface of the commutator 7.

In this state, when the brushes 11A and 11B are energized to drive the electric pump P and a current is passed through the commutator 7, the electric motor A is rotated by the current flowing between the magnetic force line due to the magnetic field and the armature 8. The rotation is output from the rotary shaft 2. On the other hand, in the liquid pump B, the electric motor A
The inner rotor 15 and the outer rotor 16 rotate relative to each other due to the rotation of the rotating shaft 2 to change (increase or decrease) the chamber volume in the pump chamber 17, and when the chamber volume of the pump chamber 17 increases, liquid suction is performed. The liquid is sucked into the pump chamber 17 through the passage 18A, and when the volume of the pump chamber 17 decreases, the liquid inside the pump chamber 17 is discharged from the pump chamber 17 into the inside 1A of the housing 1 through the liquid discharge passage 18B. .

Then, the liquid discharged into the inside 1A of the housing 1 flows down through the inside 1A of the housing 1, and the liquid discharge passage of the first lid 3 is discharged.
40 is discharged to the outside and consumed.

Here, when the spring force of the spring 28 in the pressure response device C is discharged from the liquid pump B to a desired liquid discharge pressure (for example, 2.5 kg / cm ² ) or more, the pressure of the liquid flowing through the inside 1A of the housing 1 is increased. The partition 21 is set to move toward the atmosphere chamber 22 against the spring force of the spring 28.

That is, for example, when the pressure of the liquid flowing in the inside 1A of the housing 1 rises to 2.6 kg / cm ² , the pressure of this liquid enters the pressure chamber 23 through the pressure introducing passage 25 communicated with the inside 1A of the housing 1. To work. According to this, the lower surface of the partition body 21 that opens into the pressure chamber 23 receives the applied pressure, and
Is moved to the atmosphere chamber 22 side (upward in FIG. 1) against the spring force of the spring 28.

The movement of the partition 21 is transmitted to the brush 11B via the connecting member 26, the brush 11B is separated from the outer peripheral surface of the commutator 7, and the commutator 7 and the brush 11B are in a non-contact state. Therefore, the electric current flowing through the armature 8 is dropped, so that the electric motor A is stopped and the liquid pump B is also stopped.

On the other hand, since the liquid in the inside 1A of the housing 1 still has the discharge pressure, it continues to be discharged through the liquid discharge passage 40. According to the consumption of the liquid from the liquid discharge passage 40,
The liquid pressure in the interior 1A of the housing 1 drops. (It changes to the atmospheric pressure side.) Then, the liquid pressure in the inside 1A of the housing 1 is, for example, 2.
At 4 kg / cm ² , the pressure in the pressure chamber 23 also decreases in synchronization with it, so that the partition body 21 moves to the pressure chamber 23 side (downward in FIG. 1) by the spring force of the spring 28, and this partition body The movement of 21 is transmitted to the brush 11B via the connecting member 26, and the brush 11B again contacts the outer peripheral surface of the commutator 7.

Therefore, a current again flows through the armature 8, the current motor A is driven, the liquid pump B performs a pumping action again, and the liquid is supplied to the inside 1A of the housing 1. After that, the electric motor A is repeatedly operated and stopped according to the pressure of the liquid discharged from the liquid pump B, so that a desired liquid discharge pressure (not higher than a constant discharge pressure) can be obtained.

Incidentally, since the discharge amount of the liquid pump B is generally set to a discharge amount sufficiently larger than the amount actually consumed through the liquid discharge passage 40, the operation of the liquid pump B is temporarily stopped. However, the discharge amount does not become insufficient even if the liquid is not discharged to the inside 1A of the housing 1.

The structure of the liquid pump and the structure of the pressure response device C are not limited to those in the embodiment. The liquid discharge pressure input to the pressure response device C may be anywhere inside the housing 1 1A and the liquid discharge passage 40 as long as it is on the discharge side of the liquid pump B.

Furthermore, the discharge pressure of the liquid discharged from the electric pump P varies depending on the equipment used. For example
Do not deliver a discharge pressure of 1 kg / cm ² or more. Do not deliver a discharge pressure of 5 kg / cm ² or more. There are various types such as the above, but when changing the discharge pressure, it is possible to respond by changing the set spring force of the spring 28 by screwing the adjuster 27.

That is, if the set spring force of the spring 28 is weakened, a weak liquid discharge pressure can be obtained, and if it is strengthened, a strong liquid discharge pressure can be obtained.

〔The invention's effect〕

As described above, according to the electric pump of the present invention, when the discharge pressure of the liquid discharged from the liquid pump rises above the set constant pressure, the pressure responding device operates by sensing the pressure of the liquid, and the brush and the rectifier are rectified. By stopping the operation of the electric pump by putting it in a non-contact state with the child, the discharge pressure of the liquid discharged from the electric pump can be suppressed above a set constant pressure, and the conventional relief valve is used. Compared with this, a valve seat and an on-off valve are not required, and since the above-mentioned member that requires particularly precise processing accuracy is not required, the manufacturing cost can be reduced.

In addition, since the fuel return passage is not required, it is possible to greatly improve the degree of freedom in designing the arrangement of the electric pump and the piping, especially when the fuel return passage is mounted on the vehicle.

Also, when changing the discharge set pressure of the electric pump,
The spring load of the spring in the pressure response device can be easily set by rotating the adjusting screw, which further expands the versatility of the electric pump.

Further, since the commutator and the brush inside the housing in which the liquid flows down are brought into contact and non-contact with each other, the contact point between the commutator and the brush is in the liquid at least during the operation of the electric pump, so The generation of sparks and wear could be suppressed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the electric pump according to the present invention. 1 …… Housing, 1A …… Internal 2 …… Rotary shaft, 7 …… Commutator 8 …… Armorature 11A, 11B …… Brush 21 …… Partition body, 22 …… Atmosphere chamber 23 …… Pressure chamber, 28 …… Spring 26 …… Coupling member, 27 …… Adjuster P …… Electric pump, A …… Electric motor B …… Liquid pump, C …… Pressure response device

Claims (2)

[Claims] 1. A commutator fixed to the outer circumference of a rotating shaft, a brush slidingly contacted with the commutator and connected to a power source, and an armature connected to the commutator fixed to the outer circumference of the rotating shaft.
An electric motor consisting of a pair of magnets arranged with a gap on the outer periphery of the armature; a liquid pump that sucks and discharges liquid by the output of the rotating shaft of the electric motor; A series of air chambers,
A partition body that divides into a pressure chamber into which the discharge pressure of the liquid discharged from the liquid pump is introduced; a connecting member that mechanically connects the partition body and the brush; A pressure responding device including a spring that elastically presses and contacts the brush to the commutator through a member; and when the pressure of the liquid discharged from the liquid pump rises above a certain pressure, the rising pressure is increased. By moving the compartment facing the air to the atmosphere chamber side, the contact between the brush and the commutator is brought into a non-contact state, and the current flowing from the brush to the commutator is temporarily cut off. pump. 2. The electric pump according to claim 1, wherein the spring set load of the spring in the atmosphere chamber can be adjusted.