JPH08232852A - Fuel pump - Google Patents

Abstract

PURPOSE: To provide a compact axial tilting plate type fuel pump. CONSTITUTION: A plurality of bellows 26 composing a pump chamber 29 are arranged on a circumference while their axes being parallel to each other. The bellows 26 are extended and contracted by means of a tilting plate 39 which is oscillated accompanied with rotation of a rotary shaft 16 causing pumping action. A lead valve plate 24 formed with a suction side lead valve 52 and a discharge side lead valve 53 in every pump chamber 16 is sandwiched between a pump housing 12 and a pump head 11 and fixed thereto. On the lead valve plate 24, the suction side lead valve 25 and the discharge side lead valve 25 are alternatively arranged in an arranging direction of the bellows 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leakproof and compact axial swash plate type fuel pump used for fuel supply of an internal combustion engine.

[0002]

2. Description of the Related Art As a conventional fuel pump, for example, there is a bellows row type pump as disclosed in Japanese Patent Laid-Open No. 4-191461 (particularly FIG. 1). This is because a plurality of bellows that form a pump chamber are provided, and the axes of the bellows are parallel to each other and arranged on a straight line, while a camshaft is arranged on one end side of these bellows and a plurality of cams attached to it. By this, each bellows is made to expand and contract.

However, when the bellows are arranged in a row, the size of the pump is increased due to the structure, and the camshafts are complicated because the cams for driving the bellows are out of phase. Therefore, in order to make the pump compact, Japanese Utility Model Publication No. 2-7385 (particularly the first
As shown in the drawing), it is considered that a plurality of bellows are arranged on the circumference with their axes parallel to each other, and are driven by a swash plate which makes a swinging motion.

[0004]

However, in such a conventional fuel pump as described above, the above-mentioned actual fuel opening 2-73 is used.
As shown in Japanese Patent Publication No. 85, a suction side check valve and a discharge side check valve are provided for each pump chamber on the other end side of the bellows, but the suction side check valve and the discharge side of the same pump chamber are provided. The side check valves are arranged on the same line from the center of the pump chambers to the outside, and in order to secure space for the check valves, an extra space is needed compared to the size of each pump chamber. There was a problem that the outer diameter of the pump was large.

In view of the above-mentioned conventional problems, the present invention has an object of further downsizing the axial swash plate type fuel pump.

[0006]

For this reason, in the invention according to claim 1, a plurality of pump chambers are provided and arranged on the circumference with their axes parallel to each other, while at the one end side of these pump chambers. There is a swash plate that swings and changes the volume of the pump chamber, and one for each pump chamber at the other end of the pump chamber.
In a fuel pump including one suction side check valve and a discharge side check valve, the suction side check valve and the discharge side check valve are alternately arranged in a bellows arrangement direction.

According to the second aspect of the present invention, a plurality of bellows forming the pump chamber are provided and arranged on the circumference with their axes parallel to each other. On the other hand, the bellows oscillate at one end side. A fuel pump comprising a swash plate for expanding and contracting a bellows, and one suction-side check valve and one discharge-side check valve for each pump chamber on the other end side of the bellows. The discharge-side check valve and the discharge-side check valve are arranged alternately in the bellows arrangement direction.

Further, in the invention according to claim 3, the suction side check valve and the discharge side check valve are reed valve plates formed by forming a plurality of reed valves in one plate-like body. Is
This reed valve plate is sandwiched and fixed between the joint surfaces of the pump chamber side member holding the other end side of the pump chamber (bellows) and the port side member having the suction port and the discharge port. .

Further, the invention according to claim 4 is characterized in that a seal member is attached to each joint surface of the pump chamber side member and the port side member. Further, the invention according to claim 5 is characterized in that seal members are attached to both surfaces of the reed valve plate.

[0010]

In the invention according to claim 1, the suction side check valve and the discharge side check valve are alternately arranged in the pump chamber arrangement direction (substantially circumferential direction), so that the arrangement efficiency is improved and the outside of the pump is improved. The diameter can be made small, and the size and weight can be reduced. According to the second aspect of the present invention, the pump chamber is formed of the bellows, which is advantageous when the gasoline having less leakage and lower viscosity than the plunger pump is pressurized to a relatively high pressure. Also, compared to a diaphragm pump that does not leak like the bellows, the diameter can be reduced with respect to the pressurizing stroke, which is more advantageous for compactness.

Further, in the invention according to claim 3, the plurality of suction side check valves and the plurality of discharge side check valves can be configured as one reed valve plate, and the space between the joint surfaces of the pump chamber side member and the port side member can be increased. Since it is only necessary to sandwich it between the two, it is possible to further reduce the space / cost. Further, in the inventions according to claims 4 and 5, sufficient sealability can be ensured by effectively disposing the seal member in the sandwiching portion of the reed valve plate. Particularly, in the invention according to claim 5, the seal member is 1
Since it only has to be attached to one reed valve plate, it is easy to manufacture.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 shows a fuel injection system of an internal combustion engine to which the fuel pump according to the present invention is applied. Referring to FIG. 7, fuel is pumped from a fuel tank 1 to a suction side of a fuel pump 4 according to the present invention by a feed pump 3 driven by an electric motor 2. Here, the pressure on the suction side of the fuel pump 4 is kept substantially constant by the low pressure regulator 5.

The fuel whose pressure has been increased by the fuel pump 4 is pressure-fed to the injector 6 through the high-pressure pipe and is injected from the injector 6 into the intake air of the internal combustion engine. here,
The high-pressure regulator 7 keeps the pressure in the high-pressure pipe on the discharge side of the fuel pump 4 substantially constant. FIG. 8 shows a part of a cylinder head of an internal combustion engine in which the fuel pump according to the present invention is arranged.

Referring to FIG. 8, the fuel pump 4 according to the present invention.
Is defined by a pump head (port side member) 11, a pump housing (pump chamber side member) 12, and a casing 13. The casing 13 is fixed by a bolt 14 to the cylinder head.
It is fixed to 15 outer walls. And the rotary shaft of the fuel pump 4.
16 is an intake side camshaft with a joint 17 that is free in the axial direction.
It is connected to the end of 18 and the power is transmitted by this camshaft 18. In addition, 19 is a cam and 20 is a bracket.

A suction side joint 21 attached to the suction port and a discharge side joint 22 attached to the discharge port project from the pump head 1. FIG. 1 is a front vertical sectional view of a fuel pump according to the present invention. In the following description, reference will be made to FIG. 1 when describing the upper and lower sides. With reference to FIG. 1, a pump head 11, a pump housing 12, and a casing 13 that define the outer shape of the fuel pump 4 are connected by a bolt 23. A reed valve plate 24 is sandwiched and fixed between the joint surfaces of the pump head 11 and the pump housing 12.

The pump housing 12 is provided with three bellows storage holes 25 around its center line, and these bellows storage holes 25 are open at the end surface on the casing 13 side.
Then, each bellows storage hole 25 has a cylindrical bellows 26.
Is housed, and a bellows guide 33 is slidably fitted therein. A cap 27 for closing the bellows 26 is welded to the tip (bottom end in FIG. 1) of the bellows 26, and a flange 28 is welded to the base end (top end in FIG. 1) of the bellows 26 to form a pump chamber 29 inside the bellows 26. ing.

The flange 28 of the bellows 26 has a boss portion 30, and a communication hole is formed in the boss portion 30. Then, the boss portion 30 is fitted into the concave portion on the bottom surface of the bellows storage hole 25,
An O-ring 31 is interposed in the fitting portion to prevent fuel from leaking outside the pump chamber 29. Also, the outer diameter of the boss portion 30 is smaller than the effective diameter of the bellows 26,
Although the internal pressure of 29 acts on the upper and lower surfaces of the flange 28, the lower pressure receiving surface is larger and the internal pressure of the pump chamber 29 acts upward as a whole, so the flange 28 adds to the spring action of the bellows 26 itself. The internal pressure of the pump chamber 29 stably holds the bellows storage hole 25 of the pump housing 12. In this fuel injection system, the feed pump is provided on the upstream side of the fuel pump, and the feed pressure is applied to the pump chamber 29 even during the suction stroke.

Further, the flange 28 projects outward from the bellows 26, and an annular jig or the like having an inner diameter larger than the outer diameter of the bellows 26 acts on the projecting portion 32,
Without applying excessive load to the bellows 26 due to compression,
A bellows 26 can be mounted in the bellows storage hole 25. The cap 27 of the bellows 26 is fitted in the concave portion of the bellows guide 33, and the spherical convex surface of the tip of the cap 27 is used to form the bellows guide 33.
Is in contact with However, the clearance of this fitting part is
The dimensions are set to such an extent that the bellows 26 is prevented from falling down by absorbing a processing error such as a welding deviation of the cap 27 and the flange 28 with respect to the bellows 26.

On the center line of the casing 13, a rotating shaft 16 is rotatably supported via a bush metal 34. Reference numeral 35 is an oil seal provided between the casing 13 and the rotary shaft 16. The rotary shaft 16 is connected to the camshaft at its outer end to rotate, but has a flange 36 formed at its inner end. Here, the surface of the flange portion 36 on the casing 13 side (the lower surface in FIG. 1) is the thrust washer 37.
It is rotatably supported by the casing 13 via the, and the surface (upper surface in FIG. 1) on the pump housing 12 side is inclined.

Then, on the inclined surface of the collar portion 36 of the rotary shaft 16,
One bearing ring 37 of a thrust bearing composed of the bearing ring 37, the rolling elements 38, and the bearing ring 39 is fixed, and the other bearing ring 39 is abutted against the three bellows guides 33 as a swash plate. As a result, when the rotary shaft 16 (collar portion 36) rotates,
While the rotation is blocked by the thrust bearing, the other bearing ring (hereinafter referred to as a swash plate) 39 swings, that is, each part of the swash plate 39 is moved back and forth in the axial direction, and the bellows guide 33
The bellows 26 can be expanded and contracted via.
In addition, the reason that the rotation is blocked by the thrust bearing is
This is to prevent the twist due to the rotation of the rotating shaft 16 from being transmitted to the bellows 26.

Further, the swash plate 39 has projections 40 at two outer peripheral portions, and these projections 40 are fitted with locking grooves 41 provided in the casing 13 so that the swash plate 39 can be rotated more reliably. To prevent. In addition, the swash plate 39 has a hemispherical protrusion 42 at the center of the tip surface.
And the projection 42 faces the end surface of the pump housing 12. Therefore, the rotary shaft 16 and the swash plate 39
Even if is pushed toward the bellows 26 side, the bellows 26 is prevented from being excessively compressed.

Next, the structure of the suction portion and the discharge portion of the fuel pump will be described. 2 is a plan view seen from the pump head side, FIG. 3 is a cross-sectional view taken along the line XX of FIG. 2 (a cross-sectional view of a main part of the pump head), FIG. 4 is a plan view of the pump housing, and FIG. FIG. 6 is a cross-sectional view taken along the line YY (a cross-sectional view of a main part of the pump housing). Referring to FIGS. 1 to 5 at the same time, three concave portions are formed on the upper surface of the pump housing 12 (joint surface with the pump head 11) between the adjacent bellows storage holes 25, 25, and these are sucked in. It serves as the side reed valve operation space 43.

Further, three recesses are formed on the lower surface of the pump head 11 (joint surface with the pump housing 12) almost directly above each bellows storage hole 25 on the pump housing 12 side, and these three recesses are formed on the discharge side. It is the reed valve operating space 44.
On the other hand, a suction port 45 and a discharge port 46 are formed on the upper surface of the pump head 11.

An oil passage 47 is formed in the pump head 11 so as to be connected to the suction port 45 and branched into three oil passages 47.
On the lower surface of the pump head 11 toward the suction side reed valve operating spaces 43 on the upper surface of the pump housing 12. Then, in the pump housing 12, an oil passage 48 that extends obliquely from each suction side reed valve operation space 43 and communicates with a pump chamber 29 in the bellows 26 via a communication hole in the flange / boss portion 30.
Are formed.

Further, oil passages 49 communicating with the pump chamber 29 in the bellows 26 through the communication holes in the flange / boss portion 30 and extending upward are provided, and these oil passages 49 are pump housings.
The upper surface of the pump head 12 opens toward the discharge-side reed valve operating spaces 44 on the lower surface of the pump head 11. And pump head
Three oil grooves 50 are formed on the lower surface of 11 so as to join from the discharge side reed valve operating spaces 44 toward the center.
51 communicates with the discharge port 46.

Here, the reed valve plate 24 is sandwiched between the joint surfaces of the pump head 11 and the pump housing 12, which will be described below. FIG. 6 is a plan view of the reed valve plate. Referring to FIG. 6, the reed valve plate 24 is made of a single metal plate, and has a plurality of horseshoe shapes corresponding to the suction side reed valve operation spaces 43 and the discharge side reed valve operation spaces 44, respectively. Of the reed valve 52 on the suction side and the reed valve 53 on the discharge side.
(53-1 to 53-3) are formed alternately in the arrangement direction of bellows 26 (almost circumferential direction). With such an arrangement, the pump diameter is prevented from increasing as much as possible.

Here, the suction side reed valve 52 is located between the open end of each oil passage 47 on the pump head 11 side and each reed valve operation space 43 on the pump housing 10 side, and each oil passage 47 at the time of discharge.
The open ends of the oil passages 47 are closed, and when inhaled, the open ends of the respective oil passages 47 are opened by being deformed toward the respective operating spaces 43. The discharge side reed valve 53 is located between the reed valve operation spaces 44 on the pump head 11 side and the open ends of the oil passages 49 on the pump housing 12 side, and closes the open ends of the oil passages 49 at the time of suction. However, at the time of discharge, the operation space 44 is deformed to open the opening ends of the oil passages 49.

Next, the suction / discharge operation will be described. The swash plate 39 swings as the rotary shaft 16 rotates, and the bellows guide
The bellows 26 is expanded and contracted via 33. Here, with respect to a certain bellows 26, when the swash plate 39 moves away from the bellows guide 33, the volume of the pump chamber 29 expands downward due to the spring force and feed pressure of the bellows 26 itself, Pressure drops. Along with this, fuel is guided from the suction port 45 through the oil passage 47, pushes the suction-side reed valve 52 open, and is sucked into the pump chamber 29 through the suction-side reed valve operation space 43 and the oil passage 48. .

When the swash plate 39 moves to the bellows guide 33 side and pushes it, the bellows 26 is compressed and the pump chamber
The volume of 29 is reduced and the pressure in the pump chamber 29 rises.
Along with this, the fuel acts on the discharge side reed valve 53 through the oil passage 49, pushes it open, and the discharge side reed valve operating space 4
4, it reaches the discharge port 46 through the oil groove 50 and the oil passage 51, and is discharged.

The casing 13 is filled with lubricating oil, and the lubricating oil reduces the sliding resistance and the degree of wear of each sliding portion. The casing 13 is fixed to the cylinder head 15 of the internal combustion engine by bolts 14, and an O-ring 52 is interposed on the joint surface. Next, the reed valve plate 24
An embodiment relating to the arrangement of the seal member for ensuring the sealing performance between the pump housing 12 and the pump head 11 will be described.

9 and 10 show a first embodiment relating to the arrangement of the seal member, FIG. 9 is a plan view of the joint surface of the pump housing with the seal member, and FIG. 10 is a plane of the joint surface of the pump head with the seal member. It is a figure. In this first embodiment, a seal member (for example, a sheet-shaped synthetic rubber material) 61 is fixed (for example, adhered using a method such as vulcanization adhesion) to the entire joint surface on the pump housing 12 side (see FIG. 9). A sealing member 62 is also fixed to the entire joint surface on the pump head 11 side (see FIG. 10).

Therefore, the reed valve plate is made by the seal member 61.
The sealing property between the pump housing 12 and the pump housing 12 is improved, and the sealing member 62 improves the sealing property between the reed valve plate 24 and the pump head 11. FIG. 11 shows a second embodiment relating to the arrangement of the seal member, and this figure is a plan view of the reed valve plate with the seal member.

In the second embodiment, the seal members 63 are fixed on the entire surfaces of both sides of the reed valve plate 24. Therefore, the seal members 63 on both sides of the reed valve plate 24 improve the sealing performance between the reed valve plate 24 and the pump housing 12 and the pump head 11, and also fix the reed valve plate 24 only to the easy-to-handle reed valve plate 24. Easy to make. Further, if the reed valve portion is processed after the sealing material 63 is fixed to the reed valve plate 24, the manufacturing is further facilitated.

12 and 13 show a third embodiment relating to the arrangement of the seal member, FIG. 12 is a plan view of the joint surface of the pump housing with the seal member, and FIG. 13 is a plane of the joint surface of the pump head with the seal member. It is a figure. In the third embodiment, the first seal member 64 is fixed to a part of the joint surface on the pump housing 12 side (see FIG. 12), and the pump head 11
The second and third seal members 65 and 66 are fixed to a part of the joint surface on the side (see FIG. 13).

There are six first seal members 64 fixed to the pump housing 12, and the suction side reed valve 52 and the discharge side reed valve are provided between the pump housing 12 and the reed valve plate 24.
It is arranged so as to surround each 53 (see FIG. 12). The second seal member 65 fixed to the pump head 11 separates the outer suction side reed valve 52 group and the inner discharge side reed valve 53 group between the pump head 11 and the reed valve plate 24. (See Figure 13).

A third seal member 66 also fixed to the pump head 11 is arranged between the pump head 11 and the reed valve plate 24 so as to surround the suction side reed valve 52 (see FIG. 13). . Further, referring to FIG. 12, an annular seal member 67 surrounding the open end of the suction side oil passage 49 is provided on the joint surface on the pump housing 12 side, and referring to FIG.
An annular seal member 68 that surrounds the opening end of the discharge-side oil passage 47 is provided on the side joint surface. These seal members 67, 68
As a result, the sealability of the reed valves 52, 53 can be improved.

In the third embodiment, the seal member is directly fixed on the joint surface. However, similar to the O-ring, a groove for mounting is formed on the joint surface and is mounted in this groove. You may do it. The present invention can also be applied to other types of axial swash plate type fuel pumps, such as a type that performs a pumping action using hydraulic oil as a medium.

[0038]

As described above, according to the invention of claim 1, the suction side check valve and the discharge side check valve are arranged alternately in the pump chamber arrangement direction, so that the outer diameter of the pump is reduced. It is possible to obtain a small size, a small size and a light weight, and a space / cost reduction.

According to the second aspect of the present invention, since the bellows pump is configured, it is advantageous in pressurizing gasoline having less leakage and lower viscosity than a plunger pump to a relatively high pressure. As with the bellows, compared to a leak-free diaphragm pump, the diameter can be made smaller with respect to the pressurization stroke, and there is an effect that it is more advantageous for downsizing.

Further, according to the third aspect of the present invention, by using one reed valve plate, it is possible to further reduce the space / cost. Further, according to the inventions of claims 4 and 5, by effectively disposing the seal member in the sandwiching portion of the reed valve plate,
The effect that a sufficient sealing property can be secured is obtained. Particularly, in the invention according to claim 5, since the seal member is mounted only on the reed valve plate which is easy to handle, the manufacture is easy.

[Brief description of drawings]

FIG. 1 is a front vertical sectional view of a fuel pump showing an embodiment of the present invention.

FIG. 2 is a plan view seen from the pump head side.

3 is a cross-sectional view taken along the line XX of FIG.

FIG. 4 is a plan view of the pump housing.

5 is a sectional view taken along the line YY of FIG.

FIG. 6 is a plan view of a reed valve plate.

FIG. 7 is a diagram showing a fuel injection system of an internal combustion engine.

FIG. 8 is a diagram showing a part of a cylinder head of an internal combustion engine.

FIG. 9 is a plan view of the joint surface of the pump housing with the seal member of the first embodiment regarding the arrangement of the seal member.

FIG. 10 is a plan view of a pump head-side joint surface with a seal member according to the first embodiment.

FIG. 11 is a plan view of a reed valve plate with a seal member according to a second embodiment regarding the arrangement of the seal member.

FIG. 12 is a plan view of a joint surface on the pump housing side with a seal member of the third embodiment relating to the arrangement of the seal member.

FIG. 13 is a plan view of a joint surface on the pump head side with a seal member according to the third embodiment.

[Explanation of symbols]

 4 Fuel pump 11 Pump head (port side member) 12 Pump housing (pump chamber side member) 13 Casing 15 Cylinder head 16 Rotating shaft 18 Intake side camshaft 24 Reed valve plate 26 Bellows 27 Cap 28 Flange 29 Pump chamber 33 Bellows guide 36 Collar 37 Raceway 38 Rolling element 39 Raceway (swash plate) 43 Suction side reed valve operating space 44 Discharge side reed valve operating space 45 Suction port 46 Discharge port 47 Oil passage 49 Oil passage 52 Suction side reed valve 53 Discharge side reed Valve 61 Seal member 62 Seal member 63 Seal member 64 First seal member 65 Second seal member 66 Third seal member 67 Seal member 68 Seal member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Inoguchi Iwane 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd.

Claims (5)

[Claims] 1. A swash plate for providing a plurality of pump chambers and arranging them on the circumference with their axes parallel to each other, and swinging at one end side of these pump chambers to change the volume of the pump chambers, One for each pump chamber on the other end of the pump chamber
A fuel pump comprising two suction side check valves and a discharge side check valve, wherein the suction side check valve and the discharge side check valve are arranged alternately in the pump chamber arrangement direction. . 2. A plurality of bellows forming a pump chamber are provided.
While arranging their axes parallel to each other on the circumference, a swash plate that oscillates to expand and contract the bellows at one end side of these bellows, and one pump chamber at the other end side of the bellows A fuel pump including one intake-side check valve and a discharge-side check valve, wherein the intake-side check valve and the discharge-side check valve are alternately arranged in a bellows arrangement direction. . 3. The suction side check valve and the discharge side check valve are configured as a reed valve plate formed by forming a plurality of reed valves on a single plate-shaped body, and the reed valve plate comprises: The pump chamber side member that holds the other end side of the pump chamber and a port side member having a suction port and a discharge port are sandwiched and fixed between the joint surfaces. Fuel pump. 4. The fuel pump according to claim 3, wherein a seal member is attached to each joint surface of the pump chamber side member and the port side member. 5. The fuel pump according to claim 3, wherein seal members are attached to both surfaces of the reed valve plate.