JP2002364479A - Fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply device capable of improving efficiency and achieving miniaturization. SOLUTION: A rear plate 68 provided between a feed pump cover 69 and an inner rotor 63 and an outer rotor 64 in such a manner of freely swinging can maintain a clearance from the inner rotor 63 and the outer rotor 64 in a predetermined value. Therefore, a side clearance of the inner rotor 63 and the outer rotor 64 can be maintained in a suitable value, and a leakage amount of fuel can be reduced so that oil feeding efficiency of the fuel can be improved. Accordingly, it becomes easy to reduce a size of a feed pump 60 and secure a mounting space while reducing capacity of the inner rotor 63 and the outer roller 64 and improving efficiency. The rear plate 68 swings, and thereby the inner rotor 63 and the outer rotor 64 smoothly rotate. Thus, abnormal corrosion and seizure of the inner rotor 63 and the outer rotor 64 can be prevented and reliability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel supply device, and more particularly to a fuel supply device for an internal combustion engine (hereinafter, the "internal combustion engine" is referred to as an engine).

[0002]

2. Description of the Related Art For example, in a direct injection type engine in which fuel is directly injected into a cylinder, it is necessary to increase the injection pressure in order to atomize the injected fuel. Pumped by a rotary pump such as
The pressure of the fuel is increased by a high-pressure fuel pump, and the fuel is pressure-fed to a fuel injection valve.

Generally, a high-pressure fuel pump has a drive shaft driven by a gear or a belt on a crankshaft of an engine. The drive shaft operates the plunger and feed pump of the high-pressure fuel pump while being driven by the engine. By driving the high-pressure fuel pump with the power of the engine in this way, it is easy to increase the fuel pressure.

In the case of an inner gear type trochoid pump, the feed pump changes the interdental volume between the inner rotor and the outer rotor formed by the trochoid curve, thereby pumping up the fuel in the fuel tank and discharging it to the high-pressure fuel pump. At this time, the feed pressure, which is the discharge pressure from the feed pump, is stabilized within a predetermined range by the pressure regulating valve.

[0005]

In the above-mentioned feed pump, the clearance between the inner wall of the feed pump cover that covers the inner rotor and the outer rotor and the outer wall of the inner rotor and the outer rotor in order to increase the fuel feeding efficiency. (Hereinafter referred to as side clearance) to reduce fuel leakage and increase efficiency. However, if the side clearances of the inner rotor and the outer rotor are too small, it is not possible to absorb processing variations of the members, and there is a possibility that abnormal wear or seizure of the members may occur. For this reason, it is necessary to set the above-mentioned side clearance to a predetermined value or more while sacrificing the fuel feeding efficiency. As a result, there is a problem that the size of the device becomes large and it is difficult to secure a mounting space.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a fuel supply device which achieves high efficiency and has a small size. Another object of the present invention is to provide a fuel supply device that prevents abnormal wear and seizure of members and improves reliability.

[0007]

According to the fuel supply apparatus of the present invention, the driven member can swing between the cover member that covers the driven member rotated by the drive shaft and the driven member. The plate member provided in the can maintain the clearance between the driven member and the driven member at a predetermined value, so that the side clearance between the plate member and the driven member is maintained at an appropriate value, and the amount of fuel leakage is reduced. It is possible to increase the fuel supply efficiency by reducing the fuel consumption. Thus, the efficiency of the driven member is reduced by reducing the capacity of the driven member, and it is easy to secure the mounting space by reducing the size of the device. In addition, the rotation of the driven member can be made smooth by the swinging motion of the plate member, and abnormal wear and seizure of the driven member can be prevented, thereby improving reliability.

According to the fuel supply device of the present invention, the connecting means for connecting the cover member and the plate member regulates the rotation of the plate member with respect to the cover member so that the plate member can be moved in the axial direction. Because I support
The plate member moves in the axial direction without rotating with the rotation of the driven member. This makes it easy to maintain the side clearance between the plate member and the driven member at a desired appropriate value, achieves high efficiency with a simple configuration, and can easily reduce the size of the device. .

According to the fuel supply device of the third aspect of the present invention, the urging means for urging the plate member toward the driven member is provided between the cover member and the plate member. By setting the urging force of the urging means to a load as small as possible to overcome the fuel pressure generated by the rotation of the driven member, it is possible to set the side clearance at a level at which seizure does not occur in the driven member, Reliability can be further improved. As the urging means, a simple spring member such as a leaf spring or an elastic body such as a rubber member can be used.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. One embodiment in which the fuel supply device of the present invention is applied to a fuel injection pump for a diesel engine is shown in FIGS. FIG. 2 is a sectional view of the fuel injection pump 10 shown in FIG.
And the left side surface with the rear plate 68 removed.

As shown in FIG. 1, the pump housing of the fuel injection pump 10 has a housing main body 11 and cylinder heads 12 and 13. The housing body 11 is made of aluminum. The cylinder heads 12 and 13 are made of iron, and support a plunger 30 as a movable member in a reciprocating manner. A fuel pressurizing chamber 50 is formed by the inner peripheral surfaces of the cylinder heads 12 and 13, the end surface of the check valve member 36 of the check valve 35, and the end surface of the plunger 30.

The bearing cover 14 is fixed to the housing body 11 by bolts 29 and houses the journal 15 which is a bearing for a camshaft 20 as a drive shaft. The space between the bearing cover 14 and the camshaft 20 is sealed by an oil seal 16.

The camshaft 20 is rotatably housed in the housing body 11 and the bearing cover 14. The cam 21 having a circular cross section is eccentric with respect to the camshaft 20 and is formed integrally with the camshaft 20. Plungers 30 are arranged on the opposite sides of the camshaft 20 by 180 degrees in the radial direction. The shoe 18 has a quadrangular outer shape, and the bush 1 is slidable between the shoe 18 and the cam 21 between the shoe 18 and the cam 21.
9 intervenes. Shoe 1 facing plunger 30
8 and the end face of the plunger head 30a are formed in a planar shape and are in contact with each other.

The disc portion 22 is formed integrally with the camshaft 20 ahead of the cam 21 in the direction in which the helical gear 23 urges the camshaft 20. The disk portion 22 is formed coaxially with the bearing portion 20 a of the camshaft 20 that is supported by the journal 15, and has a larger diameter than the cam 21. A washer 25 is provided between the disk portion 22 and the bearing cover 14. The end of the bearing cover 14 on the disk portion 22 side and the washer 25 constitute a locking member. Further, the housing body 11 on the side of the cam 21 opposite to the disk portion.
, A washer 26 is provided. Washers 25 and 26 are formed of a material having high hardness and low friction.

The helical gear 23 is attached to one end of the camshaft 20 and rotates together with the camshaft 20. The helical gear 23 receives a driving force from a crankshaft of the engine by a gear train (not shown). The helical gear 23 rotates in the direction of arrow A in FIG. When the helical gear 23 receives a driving force in the direction of arrow A, the camshaft 20 is urged in the direction of arrow B in FIG.

The plunger 30 is reciprocally driven by the cam 21 via the shoe 18 as the camshaft 20 rotates, and pressurizes the fuel sucked into the fuel pressurizing chamber 50 from the fuel inflow passage 51 through the check valve 35. The check valve 35 prevents fuel from flowing back from the fuel pressurizing chamber 50 to the fuel inflow passage 51.

The spring 31 urges the plunger 30 toward the shoe 18. Shoe 18 and plunger 3
Since each contact surface of 0 is formed in a flat shape,
The surface pressure between the shoe 18 and the plunger 30 decreases. Further, as the cam 21 rotates, the shoe 18 revolves without rotating while sliding on the cam 21.

Connecting members 41 and 42 for pipe connection are connected to the cylinder heads 12 and 13, respectively. A fuel discharge passage 52 is formed by the cylinder heads 12 and 13 and the connection members 41 and 42.
A check valve 37 having a check valve member 38 in the middle of the fuel discharge passage 52 is configured. The check valve 37 is connected to the fuel discharge passage 5
2 prevents the fuel from flowing back into the fuel pressurizing chamber 50. The fuel pressurized in each fuel pressurizing chamber 50 is connected to the connecting member 4.
1 and 42 are supplied to a common rail (not shown) via a fuel pipe.

As shown in FIG. 2, the inner gear feed pump 60 as a rotary pump is
The inner rotor 63 has an inner rotor 63 loosely fitted to the other end and rotated by the key 62, and an outer rotor 64 planeted by the inner rotor 63. The feed pump 60 pressurizes fuel sucked from a fuel tank (not shown) via a suction port 65 by a compression / expansion movement of gears of an inner rotor 63 and an outer rotor 64, and sends out the fuel to a discharge port 66. When the fuel pressure in the feed pump 60 exceeds a predetermined pressure, a metering valve (not shown) opens,
Excess fuel is returned to the fuel tank. Here, the inner rotor 63 and the outer rotor 64 constitute a driven member.

Inner rotor 63 and outer rotor 64
1 is provided with a front plate 67 having the above-described suction port 65 and discharge port 66. A rear plate 68 is provided on the left side surface of the inner rotor 63 and the outer rotor 64 shown in FIG. As shown in FIGS. 3 and 4,
On the surface of the rear plate 68 on the side of the inner rotor 63 and the outer rotor 64, balance ports 68a and 68b having substantially the same shape as the suction port 65 and the discharge port 66 are formed at a position facing the suction port 65 and the discharge port 66 of the front plate 67. Have been. The balance ports 68a and 68b are for allowing the fuel pressure generated by the rotation of the inner rotor 63 and the outer rotor 64 to be applied almost equally to both end surfaces of the inner rotor 63 and the outer rotor 64. A concave portion 68c is formed on the surface of the rear plate 68 on the side opposite to the inner rotor and the outer rotor, and a leaf spring 61 described later contacts the inner wall of the concave portion 68c. Also, the rear plate 68
Is formed with a pin hole 80 into which a pin 70 described later is loosely fitted. Further, on the surface of the rear plate 68, a zinc phosphate film, Ni-P plating, or CrN, WC /
Surface treatment such as ceramic coating such as C is performed to reduce the coefficient of friction and improve the surface hardness. The above surface treatment is performed at least on the rear plate 6.
8 may be applied to the surface on the inner rotor 63 and outer rotor 64 side.

Rear plate 68 as a plate member
Is connected to the feed pump cover 69 via a pin 70 fixed to the feed pump cover 69. Since the pin 70 as the connecting means is loosely fitted in the pin hole 80 of the rear plate 68, the rotation of the rear plate 68 is restricted, and the rear plate 68 is supported so as to be movable in the axial direction. The rear plate 68 can be moved to a position that maintains a predetermined clearance that is almost in close contact with the end faces of the inner rotor 63 and the outer rotor 64 on the rear plate 68 side. Swings in response to the urging force.

As shown in FIG. 1, a feed pump cover 69 as a cover member includes an inner rotor 63, an outer rotor 64, a rear plate 68, and a leaf spring 61, and a housing body 11 with a front plate 67 sandwiched by bolts 71 and the like. It is fixed to. One end of the leaf spring 61 as an urging means contacts the inner wall of the feed pump cover 69, and the other end contacts the inner wall of the recess 68 c of the rear plate 68. The leaf spring 61 urges the rear plate 68 toward the inner rotor 63 and the outer rotor 64, and the urging force of the leaf spring 61 is as small as possible to overcome the fuel pressure generated by the rotation of the inner rotor 63 and the outer rotor 64. Set to load.

Next, the operation of the fuel injection pump 10 having the above configuration will be described. The cam 21 rotates with the rotation of the camshaft 20, and the shoe 18 revolves without rotating with the rotation of the cam 21. As the shoe 18 revolves, the flat contact surfaces formed on the shoe 18 and the plunger 30 slide, whereby the plunger 30 reciprocates.

When the plunger 30 at the top dead center is lowered along with the revolution of the shoe 18, the fuel discharged from the feed pump 60 is adjusted by a metering valve (not shown). The fuel flows into the fuel pressurizing chamber 50 via the valve 35. Plunger 3 reached bottom dead center
When 0 rises again toward top dead center, the check valve 35 closes,
The fuel pressure in the fuel pressurizing chamber 50 increases. Fuel pressurization chamber 50
When the fuel pressure of the fuel cell rises above the fuel pressure on the downstream side of the check valve 37, the check valves 37 are opened alternately. The fuel supplied from the connecting members 41 and 42 to the common rail through the fuel pipe is stored in the common rail and maintained at a constant pressure. Then, high-pressure fuel is supplied from the common rail to an injector (not shown) as a fuel injection valve.

In the embodiment of the present invention described above, a rear plate 68 is swingably provided between the feed pump cover 69 and the inner rotor 63 and the outer rotor 64, and the rear plate 68 includes the inner rotor 63 and the outer rotor 64. 64 can be maintained at a predetermined value. For this reason, the side clearance between the rear plate 68 and the inner rotor 63 and the outer rotor 64 can be maintained at an appropriate value, the amount of fuel leakage can be reduced, and the fuel feeding efficiency can be increased. Accordingly, the capacity of the inner rotor 63 and the outer rotor 64 can be reduced to increase the efficiency, and the size of the feed pump 60 can be reduced to secure a mounting space. Further, the rotation of the rear plate 68 makes the rotation of the inner rotor 63 and the outer rotor 64 smooth, and the inner rotor 63 and the outer rotor 64 are rotated.
Can be prevented from abnormal wear and seizure, thereby improving reliability.

Further, in this embodiment, the rotation of the rear plate 68 is restricted by the pin 70, and the rear plate 6
8 is movably supported in the axial direction, so that the rear plate 68 moves in the axial direction without rotating with the rotation of the inner rotor 63 and the outer rotor 64. Thereby, it becomes easy to maintain the side clearance between the rear plate 68 and the inner rotor 63 and the outer rotor 64 at a desired appropriate value, thereby achieving high efficiency with a simple configuration and easily reducing the size of the feed pump 60 to a small size. Can be

Further, in this embodiment, the urging force of the plate spring 61 for urging the plate 68 toward the inner rotor 63 and the outer rotor 64 can overcome the fuel pressure generated by the rotation of the inner rotor 63 and the outer rotor 64. Since the load is set to be as small as possible, the side clearance can be set to a level at which seizure does not occur in the inner rotor 63 and the outer rotor 64, and the reliability can be further improved. In this embodiment, the leaf spring 61 is employed as the urging means, but an elastic body such as a rubber member can be used.

Further, in this embodiment, since the surface of the rear plate 68 is subjected to a surface treatment such as a zinc phosphate film, Ni-P plating, or a ceramic coating such as CrN or WC / C, the friction coefficient is increased. , And the surface hardness can be improved.
The wear of the inner rotor 63 and the outer rotor 64 can be reduced, the life of the members can be extended, and the reliability can be further improved.

In the above embodiment of the present invention, the leaf spring 61 is provided between the feed pump cover 69 and the rear plate 68. In the present invention, the leaf spring 61 can be in contact with the inner wall of the feed pump cover 69. With a protruding part,
The rear plate 68 may be provided on the outer wall on the side of the feed pump cover 69 on the side of the feed pump cover 69 so as to be capable of coming into contact with the feed pump cover 69, so that the rear plate 68 can swing about the protrusion.

Further, in this embodiment, an inner gear type trochoid pump is applied to the rotary pump of the present invention, but it goes without saying that a vane type feed pump can be applied in the present invention.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment in which a fuel supply device of the present invention is applied to a fuel injection pump for a diesel engine.

FIG. 2 is a left side view showing a state where a feed pump cover and a rear plate are removed from the fuel injection pump shown in FIG.

FIG. 3 is a plan view showing a rear plate according to one embodiment of the present invention.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

[Explanation of symbols]

 Reference Signs List 10 fuel injection pump 11 housing body (housing) 12, 13 cylinder head (housing) 20 camshaft (drive shaft) 21 cam 30 plunger (movable member) 50 fuel pressurizing chamber 60 feed pump (rotary pump) 61 leaf spring ( Urging means) 63 inner rotor (driven member) 64 outer rotor (driven member) 68 rear plate (plate member) 69 feed pump cover (cover member) 70 pin (connection means)

Claims (3)

[Claims] 1. A drive shaft, a cam that rotates together with the drive shaft, a movable member that reciprocates with the rotation of the cam to pressurize fuel sucked into a fuel pressurization chamber, and that is rotated by the drive shaft. A rotary pump for sucking and pressurizing fuel in a fuel tank by the rotation of the driven member, and discharging the fuel to the fuel pressurizing chamber. A cover member that covers the inside of the driving member, a plate member that is swingably provided between the cover member and the driven member, and that can maintain a clearance with the driven member at a predetermined value; A fuel supply device comprising: And a connecting means for connecting the cover member and the plate member, restricting rotation of the plate member with respect to the cover member, and supporting the plate member so as to be movable in the axial direction. The fuel supply device according to claim 1, wherein 3. The fuel according to claim 1, further comprising an urging means provided between the cover member and the plate member, for urging the plate member toward the driven member. Feeding device.