JPH0727031A - Fuel pump for automobile - Google Patents

Abstract

PURPOSE:To prevent a pump operating sound from its emission by coating a housing with a sound absorbing material consisting of foaming resin material having a film occupying factor in a specific value or more, in a pump arranged in a fuel tank of an automobile by integrally building a motor part and a pump part in the housing. CONSTITUTION:In a pump main unit, a motor part 12 built in a housing 10 is driven to operate a pump part 13. Then, fuel is sucked from a suction port 30 of a pump body 7 and delivered from a delivery port 31 of a lower cover 15, and further the fuel, after it is supplied to a motor chamber 18 partitioned between an upper cover 14 and the lower cover 15, is fed out from a feed port 28 of the upper cover 14. Here in the periphery of the housing 10, a sound absorbing material 8, consisting of foaming resin material, for instance, gasolineproof polyurethane foam or the like having 75% or more film occupying factor, is wound to completely coat the housing. Thus by efficiently absorbing a pump operating sound, it is prevented from being emitted to the outside of this pump.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump for automobiles.

[0002]

2. Description of the Related Art As a fuel pump for an automobile, a so-called in-tank type in which a motor unit and a pump unit are integrally incorporated in a housing and arranged in a fuel tank of the automobile is generally used. . Further, some of the in-tank type are provided with a roller vane type, a Wesco (circumferential flow) type, and an inner gear type pump portion. In particular, the inner gear type pump portion is of a positive displacement type which performs a pumping action by the meshing of the inner teeth of the outer rotor and the outer teeth of the inner rotor. It is disclosed in the official gazette.

[0003]

Since the fuel pump, especially the fuel pump having the inner gear type pump portion, is a kind of gear pump, when the rotor of the pump portion always rotates while sliding on the wall surface of the pump chamber. A loud operating noise is generated,
The problem of loud noise remains. Further, in addition to the sliding portion between the rotor and the wall surface of the pump chamber, the operating noise is generated from the sliding portion between the armature commutator and the brush, or the sliding portion between the armature shaft and the bearing. Occur. Further, in recent years, the quality of automobiles has been improved, and the noise of the entire vehicle has been reduced. Therefore, there is a strong demand for low noise even for the fuel pump arranged in the fuel tank. However, since the fuel pump has the sliding portion as described above, there is a limit in reducing noise only by reviewing the structure without deteriorating the performance, and it is very difficult to satisfy the above requirement.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a fuel pump for an automobile capable of preventing emission of pump operating noise and reducing noise. It is in.

[0005]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems is an automobile fuel pump in which a motor unit and a pump unit are integrally incorporated in a housing and arranged in a fuel tank of the automobile. The housing has a membrane occupancy of 75
% Or more of the sound absorbing material made of foamed resin material.

[0006]

According to the above-mentioned means, the pump operating sound is effectively absorbed by the sound absorbing material made of the foamed resin material having the film occupancy ratio of 75% or more, which covers the housing, so that the pump operating sound is emitted to the outside of the pump. Is prevented.

[0007]

Embodiments of the present invention will be described with reference to the drawings. First, an in-tank type fuel pump for automobiles will be described. In FIG. 1, which is a sectional view of the fuel pump, a motor portion 12 is incorporated in a cylindrical metal housing 10, and an inner gear type pump portion 13 is incorporated under the motor portion 12. A synthetic resin upper cover 14 is press-fitted and crimped onto the upper end surface of the housing 10. Further, a lower cover 15 made of a synthetic resin and a pump body 7 are attached to the lower end surface of the housing 10 with a spacer 16 interposed therebetween. In the housing 10, the upper cover 14
A motor chamber 18 is formed between the lower cover 15 and
In addition, the lower cover 15, the pump body 7, and the spacer 1
A pump chamber 19 is formed by 6.

In the motor section 12, a pair of magnets 20 are fixed to the inner peripheral surface of the housing 10. The upper and lower ends of the shaft 4 of the armature 1 arranged in the motor chamber 18 are rotatably supported by the upper cover 14 and the lower cover 15 via slide bearings 5a and 5b, respectively. The upper cover 14 includes a brush 2 that is in sliding contact with the commutator 3 of the armature 1 and is urged by a spring 21. The brush 2 is electrically connected to an external connection terminal (not shown) via the choke coil 22. Further, the upper cover 14 is provided with a delivery port 28 for connecting a fuel supply pipe leading to a fuel injection valve of an engine (not shown). A check valve 25 for preventing a back flow of fuel is incorporated in the delivery port 28.

In the pump portion 13, the pump chamber 19 is provided with an inner rotor 6a and an outer rotor 6b which form a trochoid type internal gear. The inner rotor 6a has external teeth, and the outer rotor 6a
b has internal teeth that mesh with its external teeth. The inner rotor 6a is rotatably supported by a support shaft 27 provided on the pump body 7. A joint 28 attached to the lower end of the shaft 4 of the armature 1 is connected to the inner rotor 6a. The pump body 7 is provided with a suction port 30, while the lower cover 15 is provided with a discharge port 31.

In the vehicle fuel pump, the pump section 13 is operated as the motor section 12 is driven by turning on the ignition switch using a battery (not shown) of the vehicle or the like as a power source. As a result, the fuel in the fuel tank is pumped up from the suction port 30 to the inner gear type pump unit 13, sent to the motor chamber 18 from the discharge port 31 of the lower cover 15, and further passes through the motor chamber 18 to the delivery port of the upper cover 14. It is discharged from 28.

Next, the main part will be described in detail. In the automobile fuel pump described above, the housing 10 is wound with a sound absorbing material 8 made of a foamed resin material such as a gasoline-resistant polyurethane home or polyethylene home, and the outer periphery of the housing 10 is almost entirely covered. ing. The sound absorbing material 8 effectively absorbs the pump operating sound generated from each sliding portion by the pump operation and prevents the pump operating sound from being emitted to the outside of the pump, thereby effectively exhibiting the noise reducing effect. As a thing, the film occupancy rate is 75
% Or more is adopted. The sliding portions that generate the pump operating sound include sliding portions between the rotors 6a and 6b and the wall surface of the pump chamber 19, sliding portions between the commutator 3 of the armature 1 and the brush 2, or the armature 1. Examples thereof include sliding parts between the shaft 4 and the bearings 5a and 5b.

The film occupancy of the sound absorbing material 8 will be described with reference to the explanatory view of FIG. The foamed resin material is provided with the bubbles 8a partitioned by the bubble walls 8b, and a cross-sectional area thereof shows a film (see a hatched portion in the drawing, which is denoted by reference numeral 9) for blocking the bubbles 8a. The film occupancy X is represented by X = (A / B) × 100, where A is the number of films 9 in an area of 25 mm ² and B is the number of bubbles 8a in the same area. For example, in FIG. 2, the number A of the films 9 is 2,
Assuming that the number B of the bubbles 8a is 18, X = (2/18) × 100 = 11.1 ... and the film occupancy X is about 11%.

The relationship between the membrane occupancy X calculated as described above and the noise in the fuel of the fuel pump is shown in FIG. The relationship is that the pump speed of the fuel pump is 3600 rpm,
The pump discharge pressure was 196 kPa, and the measurement position was 3 cm from the pump in the fuel.
It is indicated by a mark. The sound absorbing material 8 is a foam resin material made of polyurethane home or polyethylene home, and has a thickness of 6 m.
m. As shown in FIG. 3, the sound absorbing material 8 having a film occupancy rate of less than 50% has almost no noise reducing effect. Note that data with a film occupancy rate of less than 50% is omitted because it is almost the same as that with no sound absorbing material. Further, when the membrane occupancy rate is increased to 50% or more, the noise in the fuel decreases, and becomes substantially constant after exceeding 75%. Therefore, as described above, a good noise reduction result can be obtained by setting the film occupancy rate of the sound absorbing material 8 to 75% or more.

Further, FIG. 4 shows the measurement results of the pump noise of the fuel pump in which the foamed resin material having the film occupancy rate of 90% is adopted as the sound absorbing material 8. In FIG. 4, the horizontal axis represents the frequency and the vertical axis represents the noise in the fuel. The solid line shows the measurement result when the fuel pump is provided with a sound absorbing material, and the fuel pump is not provided with a sound absorbing material. The measurement result of the case is shown by a chain double-dashed line. As is clear from the figure, the fuel pump provided with the sound absorbing material achieved a significant noise reduction effect as compared with the case where the sound absorbing material was not provided. The measurement conditions such as the pump rotation speed of the fuel pump, the pump discharge pressure, and the measurement position were the same as those shown in FIG. The present invention can be applied to a fuel pump having a roller vane type or Wesco type pump portion in addition to the inner gear type of the embodiment.

[0015]

According to the present invention, since the housing is covered with the sound absorbing material made of the foamed resin material having the film occupancy ratio of 75% or more, it is possible to prevent the pump operating noise from being emitted to the outside of the pump
Noise can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example.

FIG. 2 is an explanatory diagram of a film occupancy rate of a sound absorbing material.

FIG. 3 is a characteristic diagram showing a relationship between a membrane occupancy rate and pump noise.

FIG. 4 is a characteristic diagram showing measurement results of pump noise.

[Explanation of symbols]

 8 Sound Absorbing Material 10 Housing 12 Motor Section 13 Pump Section

Claims (1)

[Claims] 1. A fuel pump for an automobile, in which a motor part and a pump part are integrally incorporated in a housing and arranged in a fuel tank of the automobile, wherein the housing has a resin foam material having a film occupancy rate of 75% or more. Automotive fuel pump covered with a sound absorbing material.