JP4561761B2 - Fuel supply device - Google Patents

Description

  The present invention relates to a fuel supply device that pumps fuel in a fuel tank to an injector or the like of an internal combustion engine for a vehicle, and more particularly to a structure with improved mounting properties and vibration resistance in the fuel tank.

  In order to capture foreign matters such as dust contained in the fuel and to stably supply this fuel to the injector of the fuel injection device attached to the engine, for example, nylon such as nylon provided in the suction port of the fuel pump. First, the impurities in the fuel tank are removed by a suction filter with a relatively rough mesh. And for impurities including wear powder such as brushes and commutators that pass through this suction filter or generated in the motor part constituting the fuel pump, the downstream side of the fuel pump (see the fuel flow path, It is widely known that the fuel is captured by a high-pressure filter, for example, a paper filter element, disposed in the next stage of the fuel pump.

  By the way, since the suction filter is positioned at the so-called uppermost stream in the fuel supply, it is generally positioned at the bottom of the fuel tank so that the fuel can be supplied even when the fuel in the fuel tank decreases. On the other hand, in order to send the fuel discharged from the high-pressure filter without stagnation, for example, to a discharge pipe provided in the flange, the high-pressure filter is often disposed just below the upper surface of the flange, that is, the fuel tank. That is, as long as the fuel supply device is housed in a fuel tank having a limited height dimension, a case where the fuel supply apparatus occupies the entire height dimension is sufficiently conceivable (see, for example, Patent Document 1).

Japanese Patent No. 3256973 (page 3, right column, line 9 to page 4, left column, line 49, FIG. 1)

  As is clear from FIG. 1, in this patent document 1, since a fuel pump having a relatively large volume is used, the fuel pump and the high-pressure filter are wrapped, that is, a substantially C-shaped annular high-pressure filter (patent In Document 1, a fuel pump is accommodated in the inner periphery of a filter housing (hereinafter referred to as a housing). Therefore, the clearance between the upper surface opening of the fuel tank and the housing is extremely small. Therefore, when the fuel supply device is housed in the fuel tank, there is a risk of contact between the edge portion of the upper surface opening and the housing, and there has been a concern about fuel leakage from the housing due to damage caused by this contact.

  On the other hand, in view of the essence of this Patent Document 1, the housing is further divided into a first housing (lid) and a second housing (lower housing) in an insulating and conductive manner. Can be insert molded, and static electricity can be dissipated from the lower housing. However, as a result, a lower housing that covers the height dimension of the filter element is required, and the excess is that the welded portion between the lid and the lower housing to prevent fuel leakage is the root where high stress generation is sufficiently expected. It means that it must be in the vicinity. In general, the strength of the welded part of the resin tends to be lower than the strength of the base material of the resin.Therefore, if strong vibration or the like is applied when the vehicle travels, the welded part may be damaged, which may cause fuel leakage. there were.

  The present invention has been made to solve the above-mentioned problems, but prior to solving this problem, other inventors of the applicant of the present invention achieved further miniaturization of the fuel pump. . That is, the yoke constituting the fuel pump is a first cylindrical yoke in which a rare earth ring magnet is arranged on the inner circumference, and a first yoke provided on the outer circumference of the first cylindrical yoke at a position corresponding to the magnet. Since it is composed of two cylindrical yokes, even a rare-earth magnet with a high coercive force that requires a strong magnetizing force, the degree of freedom of the magnetic circuit configuration by this magnet and the yoke is increased, and the magnet is magnetized. A reduction in the size of the device, and in particular a reduction in the axial direction of the fuel pump, was achieved (details according to WO 2004/073145). Accordingly, an object of the present invention is to obtain a fuel supply apparatus that does not cause fuel leakage from the filter case that houses the filter element, by using a shortened fuel pump, while having a weld portion. It is what.

  A fuel supply device according to the present invention includes a flange attached to an upper opening of a fuel tank, a fuel pump that discharges fuel from the fuel tank, and a high-pressure filter that filters fuel discharged from the fuel pump, The filter case in which the high-pressure filter is installed is composed of upper and lower layers of an upper case and a lower case, and the upper case is integrally formed with the flange, and the fuel pump is disposed below the lower case. In addition, it is fitted to the high-pressure filter so as to have a substantially coaxial arrangement.

  As described above, the present invention can provide a fuel supply device that is easy to assemble in a fuel tank and has improved reliability without causing fuel leakage.

Embodiment 1 FIG.
1 is an external perspective view of a fuel supply apparatus according to Embodiment 1 of the present invention, and FIG. 2 is an exploded perspective view of FIG. FIG. 3 is a cross-sectional view of the fuel pump in FIG.

  As shown in FIG. 1, the fuel supply apparatus 101 includes an upper case 1 a that contains an element that becomes a high-pressure filter, which will be described later, and a flange 1 that is an insulating resin that includes a discharge pipe 1 b by integral molding, an upper case 1 a and heat. A lower case 2 that is also an insulating resin fixed by plate welding, a pump holder 3 that is engaged with the lower case 2 by, for example, a snap fit and holds a fuel pump, which will be described later, and an opening of the pump holder 3 The suction filter 4 is inserted and fitted into the suction port of the fuel pump. Reference numeral 1c denotes a connector which is also integrally formed with the flange 1 and supplies power to the fuel pump. However, the display of lead wires extending from the connector 1c is omitted. The upper case 1a and the lower case 2 form a filter case 5.

  The assembly procedure of the fuel supply device 101 will be described with reference to FIG. On the outer periphery of the inner cylinder 6a formed of a conductive resin having a flange on the upper and lower sides, a sheet made of a material obtained by adding resin fibers such as polyester to pulp is molded in a chrysanthemum shape around the axis of the inner cylinder 6a. The element 6 configured by mounting the prepared member 6b is inserted into the upper case 1a. The dimension in the axial direction of the upper case 1 a is equal to the total length of the element 6. That is, when the upper collar portion of the inner cylinder 6a is brought into contact with the ceiling of the upper case 1a (in other words, the bottom surface of the flange 1) for insertion, the lower end surface of the upper casing 1a and the lower collar portion of the inner cylinder 6a. The projecting surface (convex shape not shown) is flush. On the other hand, the upper end surfaces of the lower case 2 serving as the receiving surfaces for the lower end surfaces and the projecting surfaces are also plied. That is, by adhering the upper case 1a and the lower case 2 by hot plate welding, the filter case 5 is formed as described above, and the inner cylinder 6a and the lower case 2 are also welded simultaneously. The element 6 is also fixed.

  When the element 6 is fixed, if a terminal member of a conductive resin (not shown) is attached to the lower case 2 in advance so as to be exposed on the outer surface of the lower case 2, the projecting surface and the terminal member are welded, By pulling out the ground wire from this terminal member, static electricity generated in the element 6 can be dissipated. The lower part of the inner cylinder 6a is blocked by the fixing, but the inner wall of the lower case 2 penetrates and there is a gap between the inner wall of the upper case 1a and the element 6, so that the fuel 6 can flow in. In addition, a plurality of communication holes for communicating the inside and outside of the inner cylinder 6a are provided in the vicinity of the lower part of the upper flange portion of the inner cylinder 6a, and the inner cylinder 6a communicates with the discharge pipe 1b. However, the fuel flow path from the discharge pipe of the fuel pump to the discharge pipe 1b is secured through the element 6.

  An opening 3 a is provided on the bottom surface of the pump holder 3, and a recess that matches the bottom shape of the fuel pump 7 (see FIG. 3) is formed, so that the fuel pump 7 is inserted into the pump holder 3. The fuel pump 7 is held at a predetermined position in the pump holder 3. In addition, since the suction port 21a of the fuel pump 7 is located in the opening 3a described above, the fuel in the fuel tank (not shown) is supplied to the suction filter 4 by connecting the connection portion 4a of the suction filter 4 to the suction port 21a. And is sucked in by the fuel pump 7.

  The lower case 2 is provided with a fuel suction port 2a, and the snap fit between the lower case 2 and the pump holder 3 described above is achieved by fitting the fuel pump 7 with the discharge pipe 15a via the connecting pipe 8. This is performed together with the engagement. Thereby, the fuel supply apparatus 101 is completed, that is, a fuel flow path from the suction filter 4 to the discharge pipe 1b is completed. By inserting the fuel supply device 101 from an upper surface opening of a fuel tank (not shown), the upper surface opening is closed by the flange 1, and the fuel in the fuel tank is pressurized by driving the fuel pump 7. The fuel is supplied to the injector of the fuel injection device through a fuel hose (not shown) connected to the discharge pipe 1b.

  Next, the above-described fuel pump 7 and driving thereof will be described with reference to FIG. As shown in FIG. 3, the well-known fuel pump 7 includes a motor unit 10 and a pump unit 20. Among these, for the motor unit 10, a magnet 13 formed in a cylindrical shape is disposed on the inner peripheral surface of the yoke 11 at a predetermined distance from the outer peripheral surface of the armature 12. 11 and a magnetic circuit are formed. The yoke 11 is composed of a first cylindrical yoke 11a and a second cylindrical yoke 11b made of STKM (carbon steel pipe for mechanical structure), and the first cylindrical yoke 11a is axially connected to the second cylindrical yoke 11b. It press-fits until it comes into contact with the convex portion 11c of the second cylindrical yoke 11b.

  The second cylindrical yoke 11b is bent at both ends in the axial direction of the shaft 14, thereby integrating the following components, that is, the bearing holder 15, the inlet housing 21, and the outlet housing 22. The bearing holder 15 formed of an insulating resin mainly composed of polyacetal is a check valve 16, a bearing 17 that supports the shaft 14, a conductive brush 18, and presses the brush 18 against the commutator 12a. The coil spring 19 and the brush 18 are housed with lead wires 18a for supplying a current through the connector 1c (see FIG. 1).

  As for the pump unit 20, first, a shaft stopper 23 is housed in an inlet housing 21 formed of resin, and the suction port 21a described above is provided. On the other hand, the outlet housing 22 is also made of resin, and is provided with a discharge port 22a for discharging fuel boosted in the flow path 24 to the armature 12 side, and houses a bearing 25 that supports the shaft 14. In addition, a D-shaped hole at the center of an impeller (impeller) 26 that is molded from resin and has a plurality of blade grooves formed on the outer periphery thereof has an end portion of the shaft 14 that has a D-shaped cross section. A certain D-cut portion 14a is fitted. A flow path 24 is formed by the plurality of blade grooves of the impeller 26 and the respective recessed grooves 21 b and 22 b of the inlet housing 21 and the outlet housing 22.

  Next, the operation of the fuel pump 7 will be described. When current is supplied to the armature 12 from a battery (not shown) through the connector 1c, the lead wire 18a, the brush 18, and the commutator 12a, the armature 12 uses the shaft 14 as a rotation axis in accordance with the principle of a known DC motor. It rotates with the impeller 26. Along with this rotation, the fuel in the fuel tank is introduced from the suction port 21a after the contaminants are removed by the suction filter 4, and after being pressurized in the flow path 24, passes through the discharge port 22a and passes through the motor unit 10. Enter the space inside. When the pressurized fuel flows in the motor unit 10 between the armature 12 and the magnet 13, the armature 12 is cooled, and the check valve 16 is opened to be discharged from the discharge pipe 15a. The discharged pressurized fuel is introduced into the element 6, where it passes through the suction filter 4 or captures foreign matters including wear powder such as the brush 18, and is then supplied to the injector of the fuel injection device. The The above is the outline and configuration of the fuel supply apparatus according to the present invention.

  Although not described in detail, the fuel pump 7 has a particularly small length in the axial direction. Therefore, as shown in FIG. Compared with this fuel supply device, its overall length is comparable. Therefore, the filter case 5 is slimmed, specifically, the outer diameter thereof is set to be equal to or smaller than that of the pump holder 3 and the shaft cores are arranged so as to be substantially coaxial. Therefore, the opening of the outer diameter of the flange 1 and the filter case 5 can be increased without increasing (changing) the outer diameter of the flange 1. This means that a sufficient clearance is ensured between the upper surface opening and the filter case 5 without unnecessarily widening the upper surface opening of the fuel tank. When assembled to the filter case, it is possible to prevent damage to the filter case 5 due to contact between the edge of the upper opening and the filter case 5, and further fuel leakage from the damage part.

  Further, since the filter case 5 is formed by welding the upper case 1a and the lower case 2, it goes without saying that there is no fuel leakage from the fixing portion due to this welding, or no decrease in fuel pressure due to leakage. Further, in the present embodiment, static electricity generated when the pressurized fuel passes through the element 6 is dissipated through the inner cylinder 6a, so that the upper case 1a having a relatively large surface area can be inexpensively insulated. Resin was used and the flange 1 was integrally formed, so that the above-described fixing portion by welding was disposed below the element 6. That is, since the fixing portion is moved away from the root portion so that the generation of stress is remarkably reduced, it is possible to provide an inexpensive fuel supply device that does not cause fuel leakage from the fixing portion due to vibration.

  Furthermore, when the filter case 5 is formed (welded), the lower case 2 of the upper case 1a, the protruding surface of the lower flange of the inner cylinder 6a, and the lower case 2 serving as the receiving surface of the lower end surface and the protruding surface. Since each upper end surface is made to be a pitch, so-called hot plate welding becomes possible, and combined with the fact that the formation of the filter case 5 is performed simultaneously with the fixing of the element 6, it is expected that the production cost will be reduced. it can. In the present embodiment, the pressure regulator used to keep the fuel pressure constant is not included in the fuel supply, but this is not necessarily added to the fuel supply device, that is, a member constituting the fuel supply device. Needless to say, for example, a system in which the pipe for surplus fuel from the discharge pipe 1b and the injector is disposed outside the so-called fuel tank and inserted therethrough can be inserted into the fuel tank. Yes.

It is an external appearance perspective view of the fuel supply apparatus in Embodiment 1 of this invention. It is a disassembled perspective view in FIG. It is sectional drawing of the fuel pump in FIG.

Explanation of symbols

1 flange, 1a upper case, 2 lower case, 2a fuel inlet,
3 pump holder, 5 filter case, 6 element (high pressure filter),
7 Fuel pump, 101 Fuel supply device.

Claims (4)

A filter case having a flange attached to the upper opening of the fuel tank, a fuel pump for discharging the fuel from the fuel tank, and a high-pressure filter for filtering the fuel discharged from the fuel pump, and in which the high-pressure filter is installed Is a fuel supply device comprising upper and lower layers of an upper case and a lower case, and the upper case is integrally formed with the flange.
The fuel supply device, wherein the fuel pump is fitted below the lower case so as to be substantially coaxial with the high-pressure filter. 2. The fuel supply device according to claim 1, wherein a contact position between the upper case and the lower case is below the high pressure filter. 2. The contact position between the lower end surface of the upper case and the upper end surface of the lower case, and the contact position between the lower end surface of the high pressure filter and the upper end surface of the lower case are the same height. The fuel supply apparatus as described. 4. The fuel supply device according to claim 2, wherein the filter case is formed by welding at the contact position.

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