JPS58119959A - Motor type fuel pump - Google Patents

Abstract

PURPOSE:To obtain a miniaturized pump for a fuel injection control device, having high efficiency and low electrical power consumption, by constituting the pump such that is of non-displacemnt and non-multistage type having one impeller. CONSTITUTION:A single closed-vane type regenerative pump having an impeller and a pump chamber is used for a fuel injection pump, having 35 to 60 numbers of grooves and a 250mu gap between the impeller and the inner wall of the chamber. When the impeller 3 rotates together with the output shaft 5 of a motor body 4, fuel sucked through a suction port 2 travels through a fuel pressure-feed gap 21 under the torque of the grooves 36 which are radially arranged in the outer periphery of the impeller 3, so that the pressure of the fuel is more and more increased and then blows into a linear part 30. At this time, since a part of the fuel which flows circularly, is ejected in the tangential direction, loss due to the change of the flow direction is small and it contributes to improvement in pump efficiency. Further, due to the tangential direction, the amount of material 1a for forming a pump chamber may be less.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a motor-type fuel pump used for injecting fuel into an automobile engine, which has a rated discharge pressure of at least 0.
．． 7 [kg/cd] and the rated discharge flow rate is at least 60 [J/hour].

Conventional fuel pumps for automobiles are low-pressure ones that pump fuel into a carburetor, and centrifugal pumps have been frequently used.

However, with the advent of electronic fuel injection control devices that inject high pressure fuel directly into the engine without using a carburetor, higher pressure pumps were required. For this reason, roller pumps such as U.S. Pat. No. 4,181,473,
Displacement pumps have come to be used, but because they are displacement pumps, the rollers make sliding contact with the walls of the pump chamber, and the discharged fluid pulsates, making noise, and the complex structure makes them expensive. Ta.

For this reason, research has been conducted into using non-displacement pumps to generate high discharge pressures, and multi-stage thin-wound pumps and multi-stage centrifugal pumps have begun to be used.

This device satisfies the desired discharge pressure, that is, a discharge pressure of at least 0.7 [kg/CIA], but because it is a multistage type, it is inefficient, large, and has a complicated structure. There were drawbacks.

The reason for this decrease in efficiency is that, as is well known, in multi-stage pumps, the product of the efficiency of the pump section of each stage and the efficiency of the pump sections of other stages is the efficiency of the entire multi-stage pump. To become.

And the deterioration in efficiency increases the power consumption of the battery,
Since the motor input current is large, the durability of the plan and commutator is also shortened, and the surface of a commutator coated with fuel such as gasoline is inherently prone to damage due to rectifying arcs, so the current is high. This is a serious drawback.Moreover, multi-stage pumps have a complicated structure and high manufacturing costs.

Also, a pump for pressure-feeding fuel to a carburetor using a single-stage regeneration pump is disclosed in U.S. Patent No. 3.259.
．． 072 etc., one of these is 0.2
Only a discharge pressure of ~0.3 [kg/ad] can be produced.

In addition, there is a fuel pump that has a two-stage regeneration pump impeller as the one closest to the present invention, but although it is a two-stage type, it can only produce a discharge pressure of barely 0.7 [1n/cd]. However, the motor current was too high which made the efficiency poor.

In view of the above problems, the present invention is a single-stage non-displacement pump, which is highly efficient and has a motor outer diameter of 30 to 45 [■
], is small, has a relatively high rated discharge pressure of at least 0.7 [k*/cd], and has a rated discharge flow rate of at least 60 [J/hour].
A normal DC motor (I!
One rotation number was 4000 [rpm] or more). The purpose is to obtain a motor-type fuel pump for automobiles.

To this end, the present invention employs a single closed-blade regenerative pump type for the impeller and pump chamber, and the number of grooves around the impeller is set to 35 to 60 from experiments, and the impeller and pump chamber wall are The gap is approximately 250 [μ].

One embodiment will be described below with reference to FIGS. 1 to 4.

1 is a pump housing which has an inlet 2; 3
3 is an impeller constituting a closed vane type regeneration pump, which is connected to the output shaft 5 of the motor body 4 and rotates in the direction of the arrow in FIG. 6 is a first motor housing, and 7 is a brush housing that becomes a second motor housing. Reference numeral 8 denotes a yoke serving as a third metal motor housing provided around the outer periphery of the magnet 9 forming the calculation value of the motor body. and,
The lower end of this yoke 8 has a caulked portion 8a located at the bottom of the pump housing 1.

10 is a bearing that supports the output shaft 5 on the motor housing 6. 11 is an armature, 12 is a planar commutator, and 13 is a bearing that pivotally supports the other output shaft of the motor body. Reference numeral 14 denotes a brush, which is connected to an external lead wire 15. 16 is also a brush, and power is supplied from the other external lead wire (not shown). Numeral 17 is a small hole that communicates the inside of the pump chamber 18 and the inside of the motor housing 6, and sends a part of the fuel inside the pump chamber 18 to the armature 11 side, cools the armature 11 and the brushes 14 and 16, and sends it to the insulating cover 20. Fuel is returned to the fuel tank in which this pump is housed through the other small hole (not shown).

Reference numeral 21 denotes a fuel pumping gap, which is formed between the inner circumferential wall 22 of the pump chamber 18 and the outer circumferential end 23 of the impeller 3, and has a substantially C-shape extending from the suction port 2 to the discharge port 24; It follows a circle centered on .

27 is a turbidity prevention wall, and this wall 27 and the impeller 53 (D
The dimensional gap between the outer 11 and the end 23 is extremely small so that the rotation of the impeller 3 is not inhibited, and the fuel flows through the discharge port 24.
This prevents any leakage of power from the side to the suction port 2 side.

Reference numeral 30 denotes a straight portion formed downstream of the discharge port 24, and the cross-sectional area of the flow path increases from the upstream side to the downstream side of the fuel flow. Further, this straight portion 30 substantially extends in the tangential direction of a circle centered on the center 26 of the impeller 3, and connects the fuel pumping gap 21 and the discharge pipe 31.

The discharge pipe 31 stands up along the axial direction of the motor body 4 and is provided a little apart from the yoke 8 that forms part of the motor housing. The vane is a check valve provided within the discharge pipe 31.

Further, a chamfered portion 35 is provided at the acute-angled tip portion of the discharge side of the leakage prevention wall 27 as shown in FIG. Also, the discharge pipe 31
The intersection point between the straight line portion 30 and the straight portion 30 is a bent portion 30a, and the bending radius of this portion 30a is preferably large so that it can be bent as smoothly as possible.

Next, the operation of the above configuration will be explained.

When the impeller 3 rotates together with the output shaft 5 of the motor body 4 in the direction of the arrow in FIG. 21, the pressure gradually increases and it flows into the straight section 30. At this time, the fuel that has flowed in an arc shape along the fuel pumping gap 21 jumps out in the tangential direction, so there is less loss due to changing the flow direction of the flow path, contributing to improved pump efficiency. The amount of material 1a used to form the structure can be small. Furthermore, the flow velocity of the fuel that has reached the straight portion 30 is decreased because the cross-sectional area of the flow path is expanded. In this embodiment, the flow passage cross-sectional area of the straight portion 30 gradually expands, so that the fuel flow velocity gradually decreases and velocity energy is efficiently converted into pressure energy, and the flow rate is efficiently converted into pressure energy on the downstream side of the discharge port 24. This has been done to reduce losses.

In the above embodiment, the rotation speed of the motor 4 is 12
[V] battery drive with rated rotational speed of 6000 [r
pml is used, and the motor outer diameter is 38 [mm].
The diameter was set as φ]. Further, the number of grooves 36 was set to 45 in the range of 35 to 60 in total on the upper and lower surfaces of the impeller. Furthermore, the lower plane of the impeller 3 and the inner wall 1 of the pump chamber 18
8a (Fig. 1) is approximately 120 [μ] ~ 18
It was set to 0 [μ].

As a result, the rated discharge pressure is 1.1 [kg/cdl
, the rated discharge flow rate was 80 [#/hour], respectively.
It satisfies the requirements of at least 0.7 [kg/cdl] and at least 60 [J/hour].

Next, experimental examples conducted in accordance with the present invention will be explained.

Generally speaking, the higher the motor rotation speed, the greater the discharge pressure.Usually, motors used in this type of fuel pump for vehicles have a battery voltage of 12 [V], a magnetic field, a commutator, and a brush. Since a DC motor with a high speed is used, there is an upper limit to the number of rotations, and if the rotation speed is too high, durability may be lost or noise may be caused.

Furthermore, if a low rotational speed is used, durability will be improved and noise will be reduced, but if the rotational speed is too low, it will be extremely difficult to generate a discharge pressure. According to the present invention, the limit is about 4
000 [rpm.

In addition, the outer diameter of the motor, that is, the outer diameter of the pump, also affects the discharge pressure, and the larger the outer diameter, the easier it is to create a product with a high discharge pressure.
However, if it is too large, it will take up a lot of space in the tank since it is an in-tank pump, which is undesirable and its limit is about 45 [mmφ]. The smaller this dimension is, the better, but the limit according to the present invention is about 30 [
l1lIlφ].

Next, although the number of grooves 36 in the impeller 3 also affects the discharge pressure, it has been found that this does not have a simple proportional relationship.

Therefore, the inventor conducted an experiment to find out the interrelationship between the minimum required motor rotational speed, the outer diameter of the motor, and the number of grooves 36 in the impeller 3 in order to produce the required rated discharge pressure and rated discharge flow rate.

One of the results is shown in Figure 5, where the horizontal axis is the number of grooves and the vertical axis is the rated discharge pressure [at a rated discharge flow rate of 60 [#/hour]].
kg/cd].

From this, it is clear that the minimum discharge pressure at the lowest discharge flow rate, that is, at least 0.7 [kg/c+1] cannot be satisfied unless the number of grooves is 35 to 60 [pieces].

In addition, in this experiment, the thrust direction clearance between the bottom plane of the impeller 3 and the top plane of the pump chamber wall tea was approximately 25 mm.
The experiment was conducted with the value set to 0 [μ]. Although this gap is small, it is virtually impossible to manufacture a gap of less than 50 [μ], and creating a gap of more than 250 [μ] has little advantage in production, and This is nonsense because the leakage flow rate increases and the efficiency of the pump chamber decreases.

Therefore, in order to satisfy the requirement of a discharge pressure of 0.7 [kg/cj1 or higher and a discharge flow rate of 60 [#/hour] or higher, the impeller must be driven by a motor at a speed of 4000 rpm or higher, and the pump outer diameter must be approximately 30 mm. It has been found that the conditions must be set to φ or more, the maximum gap is 250 [μ], and the number of grooves must be set to 35 to 60 [μ]. And in this way, without using a multi-stage pump,
A non-displacement motorized fuel pump is obtained that can be used in new electronic fuel injection control systems using one impeller and with sufficient discharge pressure.

- As mentioned above, in the present invention, a new fuel injection control device (referred to as a single point injection type), which has been attracting attention recently, has a fuel pressure that is intermediate to that of this type of device, and is about 0. 7-2 [kg/ct
M ]. ) is a non-displacement pump,
In addition, it has the excellent effect of making it possible to configure the impeller as a single non-multistage pump, and the main reason for this is that the number of grooves in the impeller is increased from 35 to 60 in closed blade type regenerative pumps. ], which was a relatively large number.

And this can increase pump efficiency,
Power consumption can be reduced and the size can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical sectional view of the pump of the present invention, FIG. 2 is a bottom view of the pump shown in FIG. 1, FIG. 3 is a sectional view of the motor housing along the arrow A-A line in FIG. 1, and FIG. 1 is a plan view showing only the impeller of FIG. 1, and FIG. 5 is an experimental characteristic diagram of the pump of the present invention. l...Pump housing, 3...Impeller, 4...
・Motor body, 6.7.8...Motor housing, 1
8... Pump chamber, 2... Suction port, 24... Discharge port, 26... Impeller center, 21... Fuel pumping gap,
27... Leak prevention wall, 30... Straight section, 31...
Discharge pipe, 30a...bending part, L...outer diameter dimension,
18a... Pump indoor wall. Representative Patent Attorney Takashi Okabe Procedural amendment (spontaneous) February 7, 1980 Patent submitted on January 12, 1980 ■ 2 Name of invention Motor fuel pump 3 Relationship with the person making the amendment Patent application 1-1 Showa-cho, Kariya-shi, Aichi Prefecture (426) Nippondenso Co., Ltd. Representative Fumi Hirayori 4th generation Osamu 1-1 Showa-cho, Kariya-shi, Aichi 448 (Kame<0566>22-3311) 5 Correction Date of order (voluntary) 6 Claims column of the specification subject to amendment, Detailed description of the invention column,
and drawings. 7. Contents of amendment a. The description will be amended as follows. (The scope of claim 11 is amended as shown in the attached sheet.
The total number of grooves was determined from experiments to be 70 to 120.
[pcs]”. (3) On page 9, lines 10 to 11, the statement "The total number of pieces on the upper and lower surfaces was 45 [pieces] falling within the range of 35 to 60 [pieces]." 90 [pieces] falling within the range of ]. ” will be corrected. (4. In the 9th line of page 11, the statement ``The number of grooves must be 35 to 60 [pieces]'' has been corrected to ``The total number of grooves must be 70 to 120 [pieces]''. (5) No. 12 Correct the statement "Number of grooves 35 to 60 [pieces]" on the 6th line of the page to "Total number of grooves 70 to 120 [pieces]". (6) "35 to 60" on the 1st line of page 13 A certain r70
~120”. b. Correct Figure 5 as shown in the attached sheet. 2. Claim 1: A motor fuel pump for automobiles with a rated discharge pressure of 0.7 [kg/cj] or more and a rated discharge flow rate of at least 60 [j/hour], which is driven by an on-board battery power source. A DC motor with a rotational speed of at least 4000 [rp] and an outer diameter of 30 [m] to 45 [W], and a closed-vane regeneration pump connected to the output shaft of this DC motor. A single impeller having a large number of grooves around the front and back surfaces, and a pump housing that forms a pump chamber for storing the single impeller and is coupled to the motor housing on the DC motor side, The total number of grooves present on the front and back surfaces of the impeller is 70 to 120 [pieces], and the gap in the motor axial direction between the bottom plane of the impeller and the top plane of the wall of the pump chamber is 250 [μ] or less. Motorized fuel pump. 2. The DC motor has a field magnet fixed to the motor housing, and has a brush that slides into contact with the commutator, and the motorized fuel pump is entirely disposed in a combustion tank, and the magnet is fixed to the motor housing. The motor-type fuel pump according to claim 1, wherein the motor-type fuel pump is of an in-tank type in which the periphery of the commutator is in contact with the fuel. 3. The motor housing has a lower motor housing forming a side surface on the other side of the pump chamber and a metal outer part housing, and the outer motor housing is caulked to the lower part of the pump housing, and the lower part According to claim 1 or 2, the impeller housing and the pump housing are brought into contact with each other to determine the gap size between the pump chamber wall and the impeller. Motorized fuel pump as described. Figure 5 Mizoaki.

Claims (1)

[Scope of Claims] 1. A motor fuel pump for automobiles having a rated discharge pressure of 0.7 [kg/aj] or more and a rated discharge flow rate of at least 60 [#/hour], which is driven by an on-board battery power source. A DC motor with a rotational speed of at least 4000 [rp*] and an outer diameter of 30 [m] to 45 [day], and a closed-vane regeneration pump connected to the output shaft of this DC motor. A single impeller having a large number of grooves around the front and back surfaces, and a pump housing that forms a pump chamber for storing the single impeller and is coupled to the motor housing on the DC motor side, The total number of grooves existing on the front and back surfaces of the impeller is 35 to 6 degrees, and the gap between the bottom plane of the impeller and the top plane of the pump chamber in the motor axial direction is 250 μ or less. motorized fuel pump. 2. The DC motor has a field magnet fixed to the motor housing, and a brush that slides into contact with a commutator, and the entire single-stroke fuel pump is disposed within a combustion tank; The motor-type fuel pump according to claim 1, wherein the motor-type fuel pump is of an in-tank type in which the periphery of the magnet and commutator is in contact with the fuel. 3. The motor housing has a lower motor housing forming a side surface on the motor side of the pump chamber and an outer motor housing made of metal, and the outer motor housing is caulked to the lower part of the pump housing, and the lower motor housing and the The motor-type fuel pump according to claim 11 or 2, characterized in that the gap size between the pump chamber wall and the impeller is determined by bringing the pump housing into contact with the pump housing.