JPH04203288A - 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 Application Field] 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 applicable to two-wheeled vehicles, four-wheeled vehicles, etc. A reliable fuel pump for LII vehicles mounted on the vehicle.

[Prior Art] A vehicular fuel t-t pump (hereinafter referred to as a fuel pump) conventionally used in the groin will be explained with reference to FIG.

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

1 is a cylindrical housing made of a magnetic material such as iron, and both ends thereof are open. .

Then, the opening [] of the housing l is connected to the bearing holder 2,
The bearing holder 2 and the pump casing 3 are fixedly disposed on the stepped portion lAl- of the housing l to close the gap.

The bearing holder 2 is formed with a fuel passage 4 whose negative side (left side in FIG. 2) opens into the housing 1 through a recess, and whose other side opens to the outside via a fuel outflow passage r-'. 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 that communicates the fuel flow path 4 divided by the retainer 6.

A GJ water pump bar 8 is disposed facing the outer end of the pump casing 3, and the housing l
The left-hand opening "I" is substantially closed by the pump casing 3 and the pump cover 8.

An annular recess 3A formed in the end surface near the outer periphery of the pump casing 3 and an annular four part 8Δ formed in the end surface near the outer periphery opposite to the end of the pump casing 3 of the pump cover 8 form an annular shape. A pump passage 9 is formed, and a fuel suction passage lo provided in the pump cover 8 is opened [=1 and the pump casing 3
A fuel discharge passage (not shown) provided in the opening is opened.

This fuel discharge passage communicates into the housing l.

Further, the pump casing 3 has a bearing 1. ] is fixedly arranged, and this bearing 11 is arranged 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.

The rotating shaft 12 includes a laminated steel plate 13A, which is made by stacking a plurality of plate-shaped steel plates each having a plurality of slit grooves. j) A coil wire wound in the slit [/groove of the laminated steel plate] An armature 13 made of the following is fixedly disposed, and a commutator 14 connected to the coil wire is fixedly disposed.

The armature 13 and the commutator 14 are in a concentric relationship with the housing l, 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 slit groove of the laminated steel plate 13Δ, the coil wire, the other brush of the pair of brushes 15, and the power source are not shown.) 16A and 16B are attached to the inner circumference of the housing l.
A pair of cylindrical permanent magnets are arranged concentrically and symmetrically opposite each other, and between the inner circumferential surface of the permanent magnets 16A and 16B and the outer circumferential surface of the armature 13. minute voids are formed.

- As mentioned above, housing 1. A pair of permanent magnets 16
A, 16B, the armadure 13, the commutator 14, and the rotating shaft 12 form a concentric relationship, and the motor section M is mainly formed by the above configuration.

The rotating shaft 12 located within the four parts 8A of the pump cover 8
A disc-shaped impeller 17 is integrally disposed at the end of the impeller 17, and a blade groove 7A 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 17A, 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 lO
The fuel is sucked in through the fuel outflow path F, and the fuel is discharged through the fuel outflow path F.

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

In such a conventional fuel pump, there is a small gap (for example, 2.5 mm) between the inner diameter of the bearing 5.11 and the outer diameter of the rotating shaft
(approximately 0μ) is formed.

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

On the other hand, the rotating shaft 12 including the armature 13 and commutator 14 must be accurately balanced in the rotational direction.

When the rotating shaft 12 rotates, (11I + receiver 5,
This is necessary in order to suppress the swinging of the rotating shaft 12 (center runout of the rotating shaft 12) within the range IJ2.

If the rotating shaft 12 is not balanced accurately,
The rotating shaft 12 swings within the bearings 5 and 11, and as a result, the rotating shaft 12 and the bearings 5 and 11 collide irregularly, producing a banging sound, which can especially affect the driving sensation of the driver when mounted on a vehicle. This is not a good thing to hear.

In recent years, there has been a particular trend toward smaller fuel pumps.

This reduces weight by downsizing the fuel pump, reduces overall vehicle weight, improves fuel economy, and increases flexibility in mounting the fuel pump in the fuel tank to which it is attached. It is necessary for this purpose.

[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 is low, and the amount of fuel discharged from the fuel pump tends to decrease.

(Here, the fuel discharge amount of the fuel pump is determined by the engine on which it is mounted, and the fuel discharge amount must not decrease due to miniaturization of the fuel pump.) In order to prevent this decrease in fuel discharge h1, the motor It is necessary to increase the rotation speed of the unit by 2".

For example, 4.00OR at armature outer diameter + 30mm
1) When M is downsized to the outer diameter of the armature + 25 mm, the speed is increased to 8.000 RPM.

Since the rotational speed of the motor section has been greatly increased in this manner, the rotating shaft including the armature and commutator must be balanced with much higher precision than in the past.

For example, outside the armature? 'l + 30 mm at 4. During OOORPM, the surface unbalance regulation fift of the armature was balanced at 90 mm gr, but at armature outer diameter + 25 mm it was 8. OOOI' (PM), it is necessary to control the armature surface unbalance regulation value at 10 mmgr.

In this way, it is necessary to balance the rotating shaft including the armature and commutator with extremely high precision, which is why balancer machines are used as machine tools for balancing or balancing tests with fixed position stop devices for detection. These devices are extremely expensive due to the need for control accuracy, and furthermore, they increase the number of man-hours for processing and inspection, which reduces the manufacturing cost of the fuel pump. This is not a good thing as it leads to increase.

The vehicle fuel pump of the present invention has been developed in view of the above-mentioned problems, and is manufactured without the need to maintain and manage the balance of the rotating shaft including the armature and commutator with extremely high accuracy when downsizing the fuel pump. It is an object of the present invention to provide the fuel pump at low cost.

[Means for Solving the Problems] In order to achieve the above object, the fuel pump for a vehicle according to the present invention has 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 motor section formed by a rotary shaft armature, a commutator integrally attached to a rotating shaft and connected to the armature, and a brush in sliding contact with the commutator; A fuel pump for a vehicle is equipped with a pump part that performs a pumping action by rotation in a housing, and a bearing that rotatably supports a rotating shaft is made of liquid crystal polymer.

[Operation] According to this configuration, when the rotating shaft and the bearing collide irregularly due to the rocking of the rotating shaft at O during operation of the fuel pump, the impact on the bearing of the rotating shaft is absorbed by the bearing made of liquid crystal polymer. As a result, the hitting noise caused by impact can be significantly reduced.

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

[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.

20 is a cylindrical bearing that supports one end of the rotating shaft 12 in the bearing holder 2 via the retainer 6; 21 is a cylindrical bearing that supports one end of the rotating shaft 12;
It is a cylindrical bearing whose other end is rotatably supported with respect to the pump casing 3, and these bearings 20 and 21 are made of liquid crystal polymer (Liguid Cr-ys shear a1.Po1.y
It is formed by injection molding.

], ] Here, liquid crystal polymer (Liguid Crystal
Polymer-r) will be explained in detail.

Liquid crystal polymers, for example, are wholly aromatic polyesters, which are made of rigid polymers, and their molecular chains are hard to bend and maintain a rod shape even in the molten state.There is little entanglement of molecules when molten, and it can be easily stabilized even when subjected to a slight shear stress. Orient in a direction.

When this is cooled, the molecules solidify in an oriented state, and this state is stably maintained.

The following characteristics are characteristic of such liquid crystal polymers.

(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 situations where the balancing accuracy of the rotating shaft 12 including the commutator 14 is not adjusted to a 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 randomly collide with the bearings 20.21.

However, in the fuel pump according to the present invention, the bearing 2
0.21 is made of liquid crystal polymer, bearing 2
0.21 collides with the rotating shaft 12, and the vibration generated is caused by the bearing 2.
0.21 and is not transmitted to the housing 1 via the bearing boulder 2 and pump casing 3.

Therefore, the housing l 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.

The reason why vibrations are absorbed particularly efficiently in the bearings 20 and 21 made of liquid crystal polymer compared to other materials is due to the large logarithmic damping rate, as is clear from Table 1.

In addition, the use of plastic as a bearing is also considered, but since plastic has a smaller logarithmic attenuation rate than liquid crystal polymer, liquid crystal plastic glue (a material that efficiently absorbs vibrations) is difficult and cannot be adopted.

The plastic mentioned here is defined by JIS K6900 [a solid material made of polymeric substances as a main raw material and shaped into a human-like and useful shape. J (j) Excludes textiles, rubber, paints, adhesives, etc.

Furthermore, the use of rubber as a bearing is also considered, but since rubber has inferior mechanical properties (tensile modulus) and heat resistance compared to liquid crystal plastic, various proofs are required before its use. It is necessary to conduct tests, and the research investment required for adoption would be large, making it impossible to implement immediately.

[Effects of the Invention] As described above, according to the vehicle fuel pump of the present invention,
A rotating shaft supported by a rotating shaft in a concentric relationship with the housing on a bearing integrally attached to the housing, and a rotating shaft supported in a rotating shaft concentrically with the housing, and a rotating shaft disposed facing each other in the housing in a concentric relationship with the rotating shaft. a pair of cylindrical permanent magnets, an armature integrally attached to the rotating shaft in a concentric relationship with the permanent magnets, and a commutator integrally attached to the rotating shaft and connected to the armature; A fuel pump for a wide vehicle that includes a brush in sliding contact with a commutator, a motor part formed by the brush, and a pump part that performs a pumping action by rotation of a rotating shaft of the motor part, in a housing. Since the bearing that rotatably supports the rotating shaft is made of liquid crystal polymer, if the balancing of the rotating shaft is not maintained and managed with extremely high precision (conventional level of balancing management), the rotating shaft will oscillate within the bearing. Even if the rotating shaft and the bearing collide irregularly, the sound or vibration transmitted from the rotating shaft to the outside from the housing via the bearing holder and pump casing will be absorbed by the bearing made of liquid crystal polymer. Since the fuel is absorbed, it is possible to provide an extremely quiet fuel pump, which is particularly suitable for use in vehicles where quietness is desirable.

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 man-hours for pressurization and inspection time due to improved 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. 1, housing 2, bearing holder 3, pump casing 6, retainer 12, rotating shaft l;3. Armadure 14 Commitator +6A, 16B Permanent magnet 20.2I Bearing M, 6 Motor section P Pump section agent Patent attorney Ike 1] Hiroshi

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 vehicle fuel pump in which a bearing that rotatably supports a rotating shaft is made of liquid crystal polymer.