JPH0419376A - Motor-driven pump - Google Patents

Abstract

PURPOSE:To restrain a delivery pressure within a predetermined constant pressure by constituting so that contact between a motor brush and a commutator is brought into a non-contact state by a pressure-actuating device in the case where a pressure of a liquid delivered from a liquid pump exceeds a constant pressure. CONSTITUTION:When brushes 11A, 11B are electrified to feed an electric current to a commutator 7 so as to drive a motor-driven pump P, an electric motor A is rotated by a magnetic line of force due to a magnetic field and an electric current flowing in an armature 8. In a liquid pump B, because of this rotation, an inner rotor 15 and an outer rotor 16 mutually rotate to pressurize a liquid drawn into a pumping chamber 17 through a liquid intake passage 18A for delivery from a liquid delivery passage 18B. When a pressure of a liquid flowing through the inside 1A of a housing 1 exceeds a preset pressure, a partitioning body 21 for receiving this liquid pressure via a pressure introduction passage 25 moves upward against a spring 28. Accordingly, the brush 11B is separated from the outside periphery of the commutator 7 to stop the electric motor A.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention comprises a commutator fixed to the outer periphery of a rotating shaft, a brush that is in sliding contact with the commutator and connected to a power source, and a brush that is connected to the commutator. an armature fixed to the outer periphery of the rotating shaft;
An electric pump consisting of a pair of magnets arranged with a gap around the outer periphery of an armature, an electric motor, and a liquid pump that sucks in and discharges liquid by the output of the rotating shaft of the electric motor, and is used in internal combustion engines. , used in fuel pumps, etc. to supply fuel to engines.

[Conventional technology]

An electric pump is composed of an electric motor and a liquid pump driven by the electric motor.

An electric motor consists of a stator consisting of field poles such as a yoke, permanent magnets, current collectors such as brushes and brush holders, supporting parts such as brackets and bearings, and an armature inserted into a slot in the armature core. , a commutator, a rotating shaft, and a rotor consisting of:

On the other hand, liquid pumps include roller vane types, impeller turbine types, multistage turbine types, roller vane and turbine combination types, and the like.

When using such an electric pump as a fuel pump for 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). It may be necessary to release the increased pressure, and an electric pump may be provided with a relief valve. This relief valve has a valve seat provided in a fuel return passage connecting a fuel discharge passage of an electric pump and a fuel tank, and an on-off valve backed up by a spring arranged opposite to this valve seat.

When the discharge pressure of the fuel discharged from the electric pump rises above a predetermined constant pressure, the opening/closing valve opens the valve seat against the spring force due to this increased fuel pressure, and returns the fuel. The fuel is returned to the fuel tank via the passage, and by releasing the fuel, the pressure of the fuel flowing in the fuel discharge passage can be maintained at a predetermined pressure state. (
Such a conventional electric pump is disclosed in Japanese Patent Application Laid-open No. 60-7919, for example.
Shown in No. 3. ) [Problems to be Solved by the Invention] This conventional electric pump is desired to solve the following points.

■The sealability between the valve seat and the on-off valve in a relief valve must be good. For this purpose, it is necessary to improve the machining accuracy of the contact area between the valve seat and the on-off valve, which increases the manufacturing cost of the product. Invite high.

■By providing a fuel return passage, it is necessary to consider piping when installing it in a vehicle, which limits the degree of freedom in design for installing it in an engine.

[Means to solve problems]

The purpose of the electric pump of the present invention is to obtain an electric pump that is inexpensive to manufacture and has a high degree of freedom in mounting on an engine. a brush that is in sliding contact with the commutator and connected to a power source; an armature that is connected to the commutator and fixed to the outer periphery of the rotating shaft; and a pair of permanent magnets that are arranged with a gap around the outer periphery of the armature. An electric motor consisting of;
In an electric pump consisting of a liquid pump that sucks in and discharges liquid using the output of the rotating shaft of an electric motor, when the pressure of the liquid discharged from the liquid pump rises above a certain pressure, contact between the brush and commutator is prevented. A non-contact state is achieved using a pressure-responsive device.

[Effect]

When the liquid pressure discharged from the liquid pump reaches a certain pressure or more, the pressure response device is activated by this increased liquid pressure, and the brush is separated from the commutator and becomes in a non-contact state.

According to this, the rotation of the electric motor is stopped, 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 increased above a certain pressure is reduced, 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.

Electric motor A will be explained.

Reference numeral 1 denotes a cylindrical housing with both ends open. A rotating shaft 2 is disposed on the longitudinal axis inside the housing 1. One end of the rotating shaft 2 is connected to a first lid that covers one side opening of the housing 1. The other end of the rotating shaft 2 is rotatably supported by the body 3 via a bearing 4, and the other end of the rotating shaft 2 is connected via a bearing 6 to a pump body 5 of a liquid pump P, which will be described later, and which is disposed on the other side of the housing l. A commutator 7 is fixedly disposed concentrically with the rotary shaft 2 on the outer periphery of the 0-rotation shaft 2 which is rotatably supported by the rotary shaft 2. An armature 8 is fixedly arranged concentrically with the commutator 7 and the armature 8 are electrically connected.

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

10A and IOB are brush holding holes provided facing each other with the commutator 7 in between;
Brushes IIA and IIB are disposed within 0A and IOB so as to be movable in contact with, non-contact with, and in directions (X-Y directions in FIG. 1) with respect to the outer circumferential surface of the commutator 7. The other end surface is in sliding contact with the outer peripheral surface of the commutator 7.

That is, the brush 11A located below 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. Note that the pressing of the brush IIB located above in FIG. 1 against the outer circumferential surface of the commutator 7 will be described later.

And brushes IIA and IIB are power supplies (not shown)
connected to. Further, 40 is a liquid discharge path bored in the first lid 3, one end of which opens into the housing l, and the other end connected to a consumption part such as an injector.

Next, liquid pump B will be explained.

The liquid pump B includes a rotor storage recess 12 formed in the pump body 5 that covers the opening on the other side of the housing 1, and a second rotor storage recess 12 that covers the opening that opens toward the outside of the rotor storage recess 12 of the pump body 5. It consists of a rotor storage chamber 14 formed by the lid 13, an inner rotor 15 mechanically connected to the rotating shaft 2, and an outer rotor 16 whose inner periphery is joined to the outer periphery of the inner rotor 15. A liquid suction passage 18A formed in the second lid 13 and a liquid discharge passage 18B formed in the pump body 5 open into the pump chamber 17 formed by the outer periphery of the pump chamber 17 and the inner periphery of the seventh outer rotor 1B. The liquid suction path 18A is connected to a liquid storage tank (not shown), and the liquid discharge path 18B is connected to a liquid storage tank (not shown).
opens into the interior LA of the housing 1. (The liquid pump B itself is well known.) Next, the pressure response device C will be explained.

Reference numeral 20 denotes a housing, and in FIG. 1, the housing 20 defines an atmospheric chamber 22 in the upper part and a pressure chamber 23 in the lower part by partitions 21 such as diaphragms.

This atmospheric chamber 22 is communicated with the atmosphere via an atmospheric air introduction passage 24, and the pressure chamber 23 is communicated with the housing l through a pressure introduction passage 25.
It communicates with the internal IA of. On the other hand, a connecting member 2B is integrally attached to the partition body 21, and the lower end 26A of this connecting member 26 is screwed onto the brush IIB located in the brush holding hole 10B. Also, inside the atmospheric chamber 22.

A spring 28 is contracted, with one end disposed on the upper surface of the partition body 21 and the other end disposed on the end surface of the adjuster 27 screwed onto the upper casing 20 of the atmospheric chamber 22.

Thus, the partition body 21 including the connecting member 26 is connected to the spring 28
The brush IIB is elastically pressed toward the pressure chamber 23 (downward in FIG. 1), and the inner end surface of the brush IIB is elastically pressed and comes into sliding contact with the outer peripheral surface of the commutator 7.

Next, its effect will be explained.

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

In such a state, when the brushes IIA and IIB are energized and current is passed through the commutator 7 in order to drive the electric pump P, the electric motor A is caused by the lines of magnetic force caused by the magnetic field and the armature 8.
The rotation is caused by the current flowing between the two, and this rotation is output from the rotating shaft 2. On the other hand, in the liquid pump B, the inner rotor 1 is rotated by the rotation of the rotating shaft 2 of the electric motor A.
5 and the outer rotor 16 mutually rotate to open the pump chamber 1.
The volume of the chamber in pump chamber 1 changes (increases or decreases).
When the chamber volume of 7 increases, liquid is sucked into the pump chamber 17 from the liquid suction path 18A, and when the chamber volume of the pump chamber 17 decreases, the liquid in the pump chamber 17 is sucked from the pump chamber 17 through the liquid discharge path 18B. It is discharged into the interior IA of the housing 1.

The liquid discharged into the interior IA of the housing 1 flows down the interior LA of the housing 1, is discharged to the outside from the liquid discharge passage 40 of the first lid 3, and is consumed.

Here, the spring force of the spring 28 in the pressure responsive device C is set to a desired liquid discharge pressure (for example, 2.5 kg/cm'').
When the pressure of the liquid discharged from the liquid pump B and flowing through the interior IA of the housing 1 increases, the partition body 21 is set to move toward the atmospheric chamber 22 against the spring force of the spring 28.

That is, for example, when the pressure of the liquid flowing in the interior IA of the housing 1 rises to 2.8 kg/cm'', the pressure of this liquid flows into the pressure chamber 23 through the pressure introduction path 25 communicating with the interior IA of the housing 1. According to this, the lower surface of the partition body 21 that opens into the pressure chamber 23 receives a pressing force, and the partition body 21 is moved against the spring force of the spring 2B toward the atmospheric chamber 22 side (in the upper direction in the first rI4). ).

This movement of the partition body 21 is performed by the brush I via the connecting member 2B.
Brush IIB is separated from the outer peripheral surface of commutator 7, and commutator 7 and brush IIB are in a non-contact state. Therefore, the electric motor A stops because the current flowing through the armature 8 drops, and the liquid pump B also stops pumping.

On the other hand, the liquid in the interior IA of the housing l still has a discharge pressure and 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 in the interior IA of the housing l continues to be discharged through the liquid discharge passage 40. Pressure decreases. (Changes to the atmospheric pressure side.) Then, when the liquid pressure in the interior IA of the housing l reaches, for example, 2.4 kg/cm'', the pressure in the pressure chamber 23 also decreases in synchronization with it, so the partition body 21 spring 2
8 moves toward the pressure chamber 23 side (downward in FIG. 1), and this movement of the partition body 21 is transmitted to the brush IIB via the connecting member 2B, and the brush 11B is moved again to the outer peripheral surface of the commutator 7. Contact.

Therefore, the electric wave flows through the armature 8 again, the electric motor A is driven, and the liquid pump B performs a pumping action again, supplying liquid to the interior IA of the housing 1. Thereafter, the electric motor A is operated according to the pressure of the liquid discharged from the liquid pump B.

By repeating the stoppage, a desired liquid discharge pressure (which does not rise above a constant discharge pressure) can be obtained.

In addition, since the discharge amount of the liquid pump B is set to be sufficiently large compared to the amount actually consumed through the liquid discharge path 40 during boat fishing, the operation of the liquid pump B may sometimes occur. Even if the liquid stops and the liquid is not discharged into the interior IA of the housing 1, the discharge amount will not be insufficient.

Note that the structure of the liquid pump and the structure of the pressure-responsive device C are not limited to the embodiments.

In addition, if the liquid discharge pressure is input to the pressure response device C on the discharge side of the liquid pump B, the input is the internal IA of the housing l,
The liquid discharge path 40 may be located anywhere.

Furthermore, the required discharge pressure of the liquid discharged from the electric pump P varies depending on the equipment used. For example, the discharge pressure should not exceed 1 kg/cm", or 5 kg/cm
There are various types, such as 0, which do not produce a discharge pressure higher than crn', but when changing the discharge pressure, it can be done by changing the set spring force of the spring 28 by screwing the adjuster 27.

That is, by weakening the set spring force of the spring 28, a weak liquid discharge pressure can be obtained, and by increasing it, a strong liquid discharge pressure can be obtained.

〔Effect of the invention〕

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 a preset constant pressure, the pressure of this liquid is sensed and the pressure responsive device is operated, and the brush and rectifier are activated. By stopping the operation of the electric pump by keeping the electric pump in a non-contact state, the discharge pressure of the liquid discharged from the electric pump can be suppressed to a set constant pressure or less. In comparison, there is no need for a valve seat or an on-off valve, and there is no need for the above-mentioned members that require particularly precise machining accuracy, making it possible to reduce manufacturing costs.

Furthermore, since the fuel return passage is no longer necessary, the degree of freedom in the design of the arrangement of the electric pump and the piping, especially when mounted on a vehicle, can be greatly improved.

Also, when changing the discharge setting pressure of the electric pump,
The spring load of the spring in the pressure-responsive device could be easily set by rotating the adjustment screw, which further expanded the versatility of the electric pump.

In addition, since the commutator and the brushes in the housing through which the liquid flows are in contact and non-contact states, the contact points between the commutator and the brushes are in the liquid at least during operation of the electric pump, so the This prevents spark generation and wear.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the electric pump according to the present invention. 1.../Using 2, Rotating shaft 8, Armature 11A, IIB, Brush 21, Division body 23, Pressure chamber 2B, Connecting member P, Electric pump B, Liquid pump 1 A, Internal 7, Commutator 22, Atmospheric chamber 28, Spring 27, Adjuster A, ,,,Electric motor C,,,,Pressure response device

Claims (3)

[Claims] (1) A commutator fixed to the outer periphery of the rotating shaft, a brush in sliding contact with the commutator and connected to a power source, an armature connected to the commutator and fixed to the outer periphery of the rotating shaft, and the outer periphery of the armature. a pair of magnets spaced apart from each other;
An electric motor consisting of an electric motor; a liquid pump that sucks in and discharges liquid by the output of the rotating shaft of the electric motor; An electric pump that uses a pressure-responsive device to make contact with the commutator non-contact. (2) The pressure-responsive device includes a casing; a partitioning body that divides the casing into an atmospheric chamber connected to the atmosphere and a pressure chamber into which the discharge pressure of the liquid discharged from the liquid pump is introduced; the partitioning body and a brush; Claim 1, comprising: a connecting member that mechanically connects; and a spring that is compressed in the atmospheric chamber and brings the brush into elastic pressing contact with the commutator via the partition and the connecting member. Electric pump as described. (3) The electric pump according to claim 2, wherein the spring setting load of the spring in the atmospheric chamber can be adjusted.