JPH04203287A - Vehicle fuel pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Field of Application] The present invention relates to a fuel pump in which a pump part is driven by a rotational force output from a motor part to perform a pumping action, and is suitable for use in vehicles such as two-wheeled vehicles and four-wheeled vehicles. Regarding the vehicle fuel pump installed.

[Prior Art] A vehicular phase pump (hereinafter referred to as a fuel pump) conventionally used for -e will be explained with reference to FIG.

The fuel pump is composed of a motor section M and a pump section P.

Reference numeral 1 denotes a cylindrical housing made of a magnetic material such as iron, which is open at both ends, and has a hole near each open end.
Step portions IA are formed on the inner circumferential surface of the housing 1, respectively.

The opening of the housing 1 is closed by the bearing holder 2 and the pump casing 3, and these, the holder 2, and the pump casing 3 are connected to the stepped portion 1 of the housing 1. AJ2 is fixedly placed to close the opening.

The bearing holder 2 is formed with a fuel passage 4 whose negative side (the left side in FIG. 2) opens with a recess into the housing J, and whose other side opens to the outside via a fuel outflow passage F.
A bearing 5 is fixedly disposed within this fuel flow path 4 via a retainer 6.

The bearing 5 is disposed at the center of the housing 1, and the retainer 6 is further provided with a communication hole 7 through which the fuel flow path 4 divided by the retainer 6 is communicated.

A pump cover 8 is disposed facing the outer end surface of the pump casing 3, and the left opening [J of the housing 1 is substantially closed by the pump casing 3 and the pump cover 8. .

The annular shape is formed by four annular portions 3A formed on the end surface near the outer periphery of the pump casing 3 and an annular recess 8A formed on the end of the pump cover 8 near the outer periphery opposite to the end surface of the pump casing 3. A pump channel 9 is formed, and a fuel suction channel 1O provided in the pump cover 8 opens into this pump channel 9, and a fuel discharge channel (not shown) provided in the pump casing 3 opens therein.

This fuel discharge passage communicates into the housing 1.

Further, a bearing 11 is fixedly disposed in the pump casing 3, and this bearing 11 is disposed at the center of the housing 1.

A rotary shaft 12 is rotatably supported by a bearing 5.11 arranged in the bearing holder 2 and the pump casing 3. reaches the recess 8A.

Thus, the rotating shaft 12 is in a concentric relationship with the housing 1.

Then, an armature 13 is fixed to the rotating shaft 12, which is made of a laminated steel plate 13A made by stacking a plurality of plate-shaped steel plates with a plurality of slit grooves, and a coil wire wound around the slit grooves of the laminated steel plate. A commutator 14 is fixedly arranged and connected to the coil wire.

The armature 13 and the commutator 14 are in a concentric relationship with the housing 1, and the commutator 14 is in sliding contact with a pair of brushes 15 that are symmetrically arranged opposite to each other, and the brushes 15 are connected to a power source.

(The slits and grooves of the laminated steel plate 1.3A, the coil wire, the other brush of the pair of brushes 15, and the power source are not shown.) A pair of cylindrical permanent magnets are arranged symmetrically and facing each other, and there is a small gap between the inner circumferential surfaces of the permanent magnets 16A and 16B and the outer circumferential surface of the armature 13. It is formed.

As mentioned above, Q[1<, housing 1. A pair of permanent magnets 1
6A, 16B, armature 13, commutator] 4,
The rotating shafts 12 are in a concentric relationship, and the motor section M is mainly formed by the configuration 111j.

The rotating shaft 12 located within the recess 8Δ of the pump cover 8
A disc-shaped impeller 17 is integrally disposed at the end of the impeller 17, and a blade groove 17A is formed over the entire circumference at the outer peripheral end of the impeller 17 facing the pump flow path 9.

A pump portion P is formed by the impeller 17, the blade groove +7A, and the pump channel 9.

As a result, the rotating shaft 1 is turned on by energizing the motor section M.
2 rotates, the pump part P is driven and the fuel suction passage 10 is rotated.
The fuel is sucked in through the fuel outflow path R, and the fuel is discharged through the fuel outflow path r.

This fuel pump is disclosed, for example, in Japanese Patent Laid-Open No. 60-79193.

In such a conventional fuel pump, a minute gap (for example, about 20!L) is formed between the inner diameter of the bearings 5, ], l and the outer diameter of the rotating shaft I2.

This is necessary in order to rotatably support the rotary shaft 12 by the bearing 5.11.

-One note, 3 on the armature. The rotating shaft 12 including the commitake J4 must be accurately balanced in the direction of rotation.

This is the rotation axis! 8 in order to suppress the swinging of the rotating shaft 12 (center runout of the rotating shaft 12) within the bearings 5.1 and 1 during the rotation of the rotary shaft 12.

If the rotating shaft 12 is not balanced accurately,
The rotating shaft 11 and the bearing 5.11 swing in the bearing 5, ]], and as a result, the rotating shaft 12 and the bearing 5.11 collide irregularly, producing a banging sound, which may be particularly harmful to the driver when mounted on a vehicle. 1j sense β1 is not desirable.

On the other hand, there has been a trend toward smaller fuel pumps in recent years.

This will reduce the weight of the fuel pump by making it smaller, reduce the weight of the entire vehicle, improve fuel economy, and allow the fuel pump to be mounted on the P fuel tank to which it is attached. It is necessary to increase the degree.

[Problems to be Solved by the Invention] Under such circumstances, it is effective to reduce the outer diameter of the housing in order to downsize the fuel pump. It needs to be small in diameter.

By reducing the outer diameter of the impeller, the circumferential speed of the blade grooves on the outer periphery of the impeller decreases, and the amount of fuel discharged from the fuel pump tends to decrease.

(Here, the amount of fuel discharged by the fuel pump is determined by the engine on which it is installed, and the amount of fuel discharged must not decrease due to the miniaturization of the fuel pump.) In order to suppress this decrease in fuel discharge II- , it is necessary to increase the rotation speed of the motor section.

For example, at armature outer diameter + 30mm, 4,, OOO
When the RPM is downsized to the outer diameter of the armature + 25mm, it is increased to 8.000R1)M.

Since the rotational speed of the motor section is increased by -F in this way, it is necessary to balance the rotating shaft including the armature and commutator with much higher precision than in the past.

For example, 4.000 at armature outer diameter + 30mm
The surface unbalance regulation value of the armature at 1≧PM was balanced at 90 mmgr', but it was changed to 8. OOORP
M, the armature surface unbalance regulation value is 1. It needs to be managed by ommgr.

In this way, it is necessary to balance the rotating shaft including the armature and commutator with extremely high precision, which means that the balancer machine is used as a machine tool for balancing, or the balancer machine is used as a machine tool for balancing, or as a balancer with a device for stopping at a fixed position for detection. It is necessary to prepare testing machines, and these devices are extremely expensive due to the improvement in control accuracy.Furthermore, they increase the number of man-hours for processing and inspection, leading to an increase in the manufacturing cost of the fuel pump. Not desirable.

The vehicle fuel pump of the present invention was developed in view of the problem described in 111j, and when downsizing the fuel pump, there is no need to maintain and manage the balance of the rotating shaft including the armature and commutator with extremely high precision. It is an object of the present invention to provide the fuel pump that is inexpensive to manufacture.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the vehicle fuel pump according to the present invention includes a bearing that is integrally attached to the housing and is rotatable in a concentric relationship with the housing. A supported rotary shaft, a pair of cylindrical permanent magnets disposed facing each other in the housing in a concentric relationship with the rotary shaft, and a pair of cylindrical permanent magnets that are integrally attached to the rotary shaft in a concentric relationship with the permanent magnets. a commutator that is integrally attached to the rotating shaft and connected to the armature; a brush that is in sliding contact with the commutator; a motor section formed by the motor; In a vehicle fuel pump that does not perform pumping action due to the rotation of the rotating shaft of the part, the outer periphery of the bearing that rotatably supports the rotating shaft is attached to a cylindrical interference member made of liquid crystal polymer. The shafts 1 and 0 are surrounded by the housing, and the shafts 1 and 0 are attached to the housing via a cylindrical member.

[Function] According to this configuration, even if the rotating shaft and the bearing randomly collide with each other due to the swinging of the rotating shaft during operation of the fuel pump, and a hammering sound is generated, the vibration of the bearing due to the collision is absorbed by the liquid crystal polymer. Since the vibration is absorbed by the cylindrical straddle member, the hitting sound caused by vibration can be greatly reduced.

As a result, a quiet fuel pump can be obtained without having to maintain or manage the balancing precision of the rotating shaft including the armature and the armature at an extremely high level of precision.

[Example] Hereinafter, an example of the fuel pump according to the present invention will be described with reference to FIG.

Note that the same reference numerals are used for the same structures as in FIG. 2, and the description thereof will be omitted.

A cylindrical bearing 20 supports one end of the rotating shaft 12 in the bearing holder 2 via the retainer 6, and is made of, for example, a copper sintered alloy.

+1 Here, in the fuel pump of the present invention, the outer circumference 2OA of the bearing 20 is made of liquid crystal polymer (Liguid Cr-ys).
It is surrounded by a cylindrical interference member 21 formed by injection molding using t;al Polymer).

That is, the inner periphery of the bearing 20 rotatably supports the outer periphery of the rotating shaft 12, and the outer periphery 2OA of the bearing 20 is fitted into the inner periphery of a cylindrical interference member 21 made of liquid crystal polymer. is the bearing holder 2 via the retainer 6.
is attached to.

On the other hand, 22 is a cylindrical bearing that rotatably supports the other end of the rotating shaft 12 in the pump casing 3, and is made of, for example, a copper sintered alloy.

The outer periphery 22A of the bearing 22 is surrounded by a cylindrical interference member 23 made of liquid crystal polymer.

That is, the inner periphery of the bearing 22 rotatably supports the outer periphery of the rotating shaft 12, the outer periphery 22A of the bearing 22 is fitted into the inner periphery of the cylindrical interference member 23 made of liquid crystal polymer, and the outer periphery of the cylindrical interference member 23 is It is attached to the pump casing 3.

Liquid Crystal Polymer (Liguid Crystal)
Polymer-r) will be explained in detail.

Liquid crystal polymers are, for example, all-aromatic polyesters, which are made of rigid polymers, and even in the molten state, the molecules and chains remain bent (rod-like), with little entanglement of molecules during melting, and a slight shear stress. Orient it in one direction by receiving it.

When this is cooled, the molecules are assimilated in a coordinated state, and that state is maintained stably.

The following characteristics are characteristic of such liquid crystal polymers.

1:3 (1) Large vibration characteristics...See Table 1 Logarithmic damping rate = 1
Attenuation per second ,
Rotating shaft 1 including armature 13 and commutator 14
2 starts rotation, at this time Armadure 13,
In situation F, where the balancing accuracy of the rotating shaft 12 including the commutator 14 is not adjusted to an extremely high level of accuracy (
Armature surface unbalance regulation value is 90mmgr
High-speed rotation of the rotating shaft 12 (8, OO
ORPM) causes the rotating shaft 12 to irregularly collide with the bearings 20, 22, producing a hammering sound.

However, in the fuel pump according to the present invention, the bearing 2
0.22 surrounding the cylindrical interference member 21.23 formed of liquid crystal polymer] 5, the collision with the rotating shaft 12 causes the bearing 20.2 to
The vibrations generated in the pump 2 are absorbed and attenuated by the cylindrical interference members 21 and 23, and are not transmitted to the housing 1 via the bearing holder 2 and the pump casing 3.

Therefore, the housing 1 forming the outermost part of the fuel pump
This eliminates the emission of vibrations to the outside of the fuel pump, that is, the hammering noise, and makes it possible to obtain a quiet fuel pump.

In the cylindrical interference member 23 formed of liquid crystal polymer,
The reason why vibrations are absorbed particularly efficiently compared to other materials is due to the large logarithmic damping ratio, as is clear from Table 1.

The use of plastic as the cylindrical interference member is also considered, but since plastic has a smaller logarithmic attenuation rate than liquid crystal polymer, it is difficult to efficiently absorb vibrations like liquid crystal plastic. is difficult and cannot be adopted.

The plastic mentioned here is defined by JIS K6900 [artificial material made mainly of polymeric substances] E5, and is a solid that has been formed into a useful shape. However, textiles, rubber, coatings, adhesives, etc. are excluded.

Furthermore, the use of rubber as the cylindrical interference member is also considered, but the mechanical properties (tensile modulus) of rubber
, because its heat resistance is inferior to that of liquid crystal plastic,
When adopting such a method, it is necessary to conduct various verification tests, and the research investment required to achieve its adoption would be large, making it impossible to implement it immediately.

[Effects of the Invention] As described in Section 2 below, according to the vehicle fuel pump of the present invention, the fuel pump is rotatably supported by a bearing integrally attached to the housing in a concentric relationship with the housing. a rotating shaft; a pair of cylindrical permanent magnets disposed facing each other in the housing in a concentric relationship with the rotating shaft; and a pair of cylindrical permanent magnets that are integrally attached to the rotating shaft in a concentric relationship with the permanent magnets. a motor section formed by an armature, a commutator integrally attached to a rotating shaft and connected to the armature, and a brush in sliding contact with the commutator; and a pump driven by rotation of the rotating shaft of the motor section. In a vehicle fuel pump that has a pump part that performs an action in a housing, the outer periphery of the bearing that rotatably supports the rotating shaft is surrounded by a cylindrical interference member made of liquid crystal polymer, and the bearing is surrounded by a cylindrical interference member. Since it is attached to the housing via a member, if the balance of the rotating shaft is not maintained and managed with extremely high precision (conventional level of balancing management), the rotating shaft will swing within the bearing, causing the rotating shaft and bearing to Even if the wheels collide irregularly and generate a hammering sound, the hammering sound is transmitted from the rotating shaft to the housing through the bearing holder and pump casing to the outside.
That is, since vibrations are absorbed by the cylindrical interference member made of liquid crystal polymer, it is possible to provide an extremely quiet fuel pump, which is especially suitable for use in vehicles where quietness is desired.

In addition, since there is no need to maintain and manage the balance of the rotating shaft with extremely high precision (the same level of management as before is sufficient), there is no need to invest in especially expensive machine tools for balancing and testing machines for detection. This eliminates the need for fuel pump manufacturing costs.

Furthermore, increases in processing and inspection time due to improvements in control accuracy can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part showing an embodiment of a vehicle fuel pump according to the present invention, and FIG. 2 is a vertical cross-sectional view of a main part showing a conventional fuel pump. I, housing 2 bearing holder 3.4 pump casing 61. Retainer 12, rotating shaft 13, armature 14 commutator 1.6A, 16B permanent magnet 20.22 bearing 21.23 cylindrical interference member M motor part P9. Pump part

Claims (1)

[Scope of Claims] A rotating shaft rotatably supported in a bearing integrally attached to the housing in a concentric relationship with the housing; a pair of cylindrical permanent magnets, an armature that is concentric with the permanent magnets and integrally attached to the rotating shaft, and a commutator that is integrally attached to the rotating shaft and connected to the armature. , a motor section formed by a pair of brushes facing and in sliding contact with a commutator, and a pump section that performs a pumping action by rotation of a rotating shaft of the motor section. A vehicular fuel pump, in which the outer periphery of a bearing that rotatably supports a rotating shaft is surrounded by a cylindrical interference member made of liquid crystal polymer, and the bearing is attached to a housing via the cylindrical interference member.