JP3351156B2 - Fuel pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art As a conventional fuel pump, there is, for example, a bellows row type pump as disclosed in Japanese Patent Application Laid-Open No. 4-191461 (in particular, FIG. 1). This is because a plurality of bellows constituting a pump chamber are provided, their axes are arranged in a straight line in parallel with each other, and a camshaft is arranged at one end of these bellows, and a plurality of cams attached to this are mounted. This allows each bellows to expand and contract.

However, when the bellows are arranged in a row, the size of the pump becomes large in structure, and the camshaft is complicated because a cam for driving each bellows is shifted in phase. To reduce the size of the pump, Japanese Unexamined Utility Model Publication No. Hei.
As shown in FIG. 1, it has been considered that a plurality of bellows are arranged on the circumference with their axes parallel to each other and driven by a swash plate that swings.

[0004]

However, in such a conventional fuel pump, the fuel pump disclosed in Japanese Utility Model Application Publication No.
As shown in Japanese Patent Publication No. 85, one suction-side check valve and one discharge-side check valve are provided for one pump chamber at the other end of the bellows. The side check valves are arranged on the same line from the arrangement center of the plurality of pump chambers to the outside, and in order to secure a space for the check valves, an extra amount is required compared to the size of each pump chamber. There is a problem that the outer diameter of the pump is large.

The present invention has been made in view of such conventional problems, and has as its object to further reduce the size of an 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 their axes are arranged on the circumference in parallel with each other, while one end of each of these pump chambers is arranged on the circumference. A swash plate that oscillates to change the volume of the pump chamber, and one swash plate at the other end of the pump chamber for each pump chamber.
In a fuel pump including one suction-side check valve and one 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 constituting the pump chamber are provided, and their axes are arranged on the circumference in parallel with each other. 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 is 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 configured as a reed valve plate formed by forming a plurality of reed valves on a single plate-like body. And
The reed valve plate is sandwiched and fixed between joining surfaces of a pump chamber side member holding the other end of the pump chamber (bellows) and a port side member having a suction port and a 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. Furthermore, the invention according to claim 5 is characterized in that seal members are mounted on both sides of the reed valve plate.

[0010]

According to the first aspect of the invention, since the suction-side check valve and the discharge-side check valve are alternately arranged in the pump chamber arrangement direction (almost in the circumferential direction), the arrangement efficiency is increased, and the outside of the pump is improved. The diameter can be made small, and miniaturization and weight reduction can be achieved. According to the second aspect of the present invention, the pump chamber is formed of bellows, which is advantageous when pressurizing gasoline having no leakage and low viscosity as compared with the plunger pump to a relatively high pressure. Further, as compared with a diaphragm pump which does not leak like the bellows, the diameter can be reduced with respect to the pressurizing stroke, which is further advantageous for downsizing.

According to the third aspect of the present invention, the plurality of suction-side check valves and the discharge-side check valves can be formed as a single reed valve plate. , The space / cost can be further reduced. Further, in the invention according to claims 4 and 5, a sufficient sealing property can be secured by arranging the sealing member effectively at the sandwiching portion of the reed valve plate. In particular, in the invention according to claim 5, the sealing member is 1
It is easy to manufacture because it only needs to be mounted on one reed valve plate.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 shows a fuel injection system for 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 pressurized by the fuel pump 4 is fed under pressure to an injector 6 through a high-pressure pipe, and is injected from the injector 6 into intake air of an internal combustion engine. here,
The pressure in the high-pressure pipe on the discharge side of the fuel pump 4 is kept substantially constant by the high-pressure regulator 7. FIG. 8 shows a part of a cylinder head of an internal combustion engine provided with a fuel pump according to the present invention.

Referring to FIG. 8, a fuel pump 4 according to the present invention will be described.
The outer shape of is determined by a pump head (port side member) 11, a pump housing (pump chamber side member) 12, and a casing 13.
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
The camshaft 18 is connected to an end of the camshaft 18 to transmit power. Incidentally, reference numeral 19 denotes a cam, and reference numeral 20 denotes a bracket.

From the pump head 1, a suction-side joint 21 attached to the suction port and a discharge-side joint 22 attached to the discharge port protrude. FIG. 1 is a front vertical sectional view of a fuel pump according to the present invention. In the following description, the upper and lower parts will be described with reference to FIG. Referring 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 bolts 23. Further, a reed valve plate 24 is sandwiched and fixed between the joining surfaces of the pump head 11 and the pump housing 12.

The pump housing 12 is formed with three bellows storage holes 25 around its center line, and these bellows storage holes 25 are open at the end face on the casing 13 side.
Each of the bellows storage holes 25 has a cylindrical bellows 26.
And a bellows guide 33 is slidably fitted. A cap 27 for closing the bellows 26 is welded to the tip (lower end in FIG. 1) of the bellows 26, and a flange 28 is welded to the base end (upper end in FIG. 1) to form a pump chamber 29 inside the bellows 26. ing.

The flange 28 of the bellows 26 has a boss portion 30 in which a communication hole is formed. Then, the boss portion 30 is fitted into the concave portion on the bottom surface of the bellows storage hole 25,
Further, an O-ring 31 is interposed in the fitting portion to prevent fuel from leaking to the outside of the pump chamber 29. The outer diameter of the boss portion 30 is configured to be smaller than the effective diameter of the bellows 26, so that the pump chamber
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. Thus, the inner pressure of the pump chamber 29 stably holds the bellows storage hole 25 of the pump housing 12. In this fuel injection system, a feed pump is provided upstream of the fuel pump, and a feed pressure is applied to the pump chamber 29 even during the suction stroke.

The flange 28 projects outward from the bellows 26, and an annular jig having an inner diameter larger than the outer diameter of the bellows 26 is applied to the overhanging portion 32, so that
Without applying excessive load due to compression to the bellows 26,
The bellows 26 can be attached to the bellows storage hole 25. The cap 27 of the bellows 26 fits into the concave portion of the bellows guide 33, and the spherical convex
Is in contact with However, the clearance of this fitting part is
The dimensions are set to such a degree as to absorb processing errors such as displacement of welding of the cap 27 and the flange 28 to the bellows 26 and prevent the bellows 26 from falling down.

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

Then, on the inclined surface of the flange 36 of the rotating shaft 16,
One of the bearing rings 37 of the thrust bearing constituted by the bearing ring 37, the rolling elements 38 and the bearing ring 39 is fixed, and the other bearing ring 39 is brought into contact with three bellows guides 33 as swash plates. As a result, when the rotating shaft 16 (the flange 36) rotates,
While the rotation is cut off by a thrust bearing, the other race (hereinafter referred to as a swash plate) 39 is oscillated, that is, each part of the swash plate 39 is moved back and forth in the axial direction, so that a bellows guide 33 is provided.
The bellows 26 is made to expand and contract via the.
The reason why the rotation is blocked by the thrust bearing is
This is to prevent the torsion caused by the rotation of the rotating shaft 16 from being transmitted to the bellows 26.

Further, the swash plate 39 has projections 40 at two locations on the outer peripheral portion, and these projections 40 are fitted into locking grooves 41 provided on the casing 13 to more reliably rotate the swash plate 39. Has been prevented. The swash plate 39 has a hemispherical projection 42 at the center of the tip surface.
The projection 42 faces the end face of the pump housing 12. Therefore, the rotating shaft 16 and the swash plate 39 can be used during assembly.
Is pressed against the bellows 26, so that the bellows 26 is not excessively compressed.

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

On the lower surface of the pump head 11 (joining surface with the pump housing 12), three concave portions are formed almost directly above the bellows storage holes 25 on the pump housing 12 side, and these are formed on the discharge side. The reed valve operation space 44 is provided.
On the other hand, on the upper surface of the pump head 11, a suction port 45 and a discharge port 46 are formed.

An oil passage 47 is formed in the pump head 11 and connected to the suction port 45 and branched into three.
The lower surface of the pump head 11 opens toward the suction side reed valve operation space 43 on the upper surface of the pump housing 12. An oil passage 48 extends obliquely from each suction side reed valve operation space 43 in the pump housing 12 and communicates with the pump chamber 29 in the bellows 26 through a communication hole in the flange boss portion 30.
Is formed.

Further, an oil passage 49 is provided which communicates with a pump chamber 29 in the bellows 26 through a communication hole in the flange boss portion 30 and extends upward, and these oil passages 49 are provided in the pump housing.
The upper surface of the pump head 12 is open toward the discharge side reed valve operation spaces 44 on the lower surface of the pump head 11. And the pump head
On the lower surface of 11, three oil grooves 50 are formed, which merge from the discharge side reed valve operation space 44 toward the center.
The communication port 51 communicates with the discharge port 46.

Here, the reed valve plate 24 is interposed between the joining surfaces of the pump head 11 and the pump housing 12, which will be described next. FIG. 6 is a plan view of the reed valve plate. Referring to FIG. 6, the reed valve plate 24 is formed of one 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. Cuts, whereby the suction side reed valve 52 (52-1 to 52-3) and the discharge side reed valve 53
(53-1 to 53-3) are formed alternately in the arrangement direction of the bellows 26 (almost circumferential direction). With such an arrangement, an increase in the pump diameter is suppressed 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.
Are closed, and when inhaled, they are deformed toward the respective operation spaces 43 to open the open ends of the oil passages 47. The discharge side reed valve 53 is located between each reed valve operation space 44 on the pump head 11 side and the open end of each oil passage 49 on the pump housing 12 side, and closes the open end of each oil passage 49 during suction. However, at the time of discharge, each of the oil passages 49 is deformed toward the operation space 44 to open the opening end of each oil passage 49.

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

When the swash plate 39 moves toward the bellows guide 33 and pushes it, the bellows 26 is compressed and the pump chamber is compressed.
The volume of the pump 29 is reduced, and the pressure in the pump chamber 29 increases.
Along with this, the fuel acts on the discharge side reed valve 53 via the oil passage 49 and pushes it open to open the discharge side reed valve operating space 4.
4. The oil reaches the discharge port 46 via 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 of each sliding portion and the progress of wear. 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, reed valve plate 24
A description will be given of an embodiment relating to an arrangement of a seal member for ensuring a sealing property between the pump housing 12 and the pump head 11.

FIGS. 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 on the pump housing side with the seal member, and FIG. 10 is a plan view of the joint surface on the pump head side with the seal member. FIG. In the first embodiment, a seal member (for example, a sheet-like synthetic rubber material) 61 is fixed (adhered using, for example, a vulcanization method) to the entire joint surface on the pump housing 12 side (see FIG. 9). Further, a seal member 62 is similarly fixed to the entire joint surface on the pump head 11 side (see FIG. 10).

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

In the second embodiment, a sealing member 63 is fixed to the entire surface of both sides of the reed valve plate 24. Therefore, the sealing members 63 on both sides of the reed valve plate 24 improve the sealing property between the reed valve plate 24 and the pump housing 12 and the pump head 11, and are fixed only to the reed valve plate 24 which is easy to handle. Manufacturing becomes easier. Further, if the reed valve portion is processed after the sealing material 63 is fixed to the reed valve plate 24, the production is further facilitated.

FIGS. 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 on the pump housing side with the seal member, and FIG. 13 is a plan view of the joint surface on the pump head side with the seal member. FIG. In the third embodiment, a first seal member 64 is fixed to a part of the joint surface on the pump housing 12 side (see FIG. 12).
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 between the pump housing 12 and the reed valve plate 24, the suction side reed valve 52 and the discharge side reed valve
53 are arranged so as to surround each of them (see FIG. 12). The second seal member 65 fixed to the pump head 11 separates the outer suction side reed valve group 52 and the inner discharge side reed valve group 53 between the pump head 11 and the reed valve plate 24. (See FIG. 13).

A third sealing member 66 similarly fixed to the pump head 11 is disposed 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 with reference to FIG.
An annular seal member 68 surrounding the open end of the discharge-side oil passage 47 is provided on the joint surface on the side. These sealing members 67, 68
Thereby, the sealing performance of the reed valves 52 and 53 can be improved.

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

[0038]

As described above, according to the first aspect of the invention, the outer diameter of the pump is reduced by disposing the suction-side check valve and the discharge-side check valve alternately in the pump chamber arrangement direction. It is possible to reduce the size and weight of the device, and it is possible to reduce the space and cost.

According to the second aspect of the present invention, the configuration as a bellows pump is advantageous in that gasoline having no leakage and low viscosity is pressurized to a relatively high pressure as compared with a plunger pump. As compared with a diaphragm pump which does not leak like the bellows, the diameter can be reduced with respect to the pressurizing stroke, and the effect of being more advantageous for downsizing can be obtained.

According to the third aspect of the present invention, the use of a single reed valve plate has an effect that the space / cost can be further reduced. Furthermore, according to the invention according to claims 4 and 5, by effectively arranging the seal member at the sandwiching portion of the reed valve plate,
The effect that sufficient sealing performance can be obtained is obtained. In particular, 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 the drawings]

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

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

FIG. 3 is a sectional view taken along line XX of FIG. 2;

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

FIG. 5 is a sectional view taken along the line YY of FIG. 4;

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

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

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

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

FIG. 10 is a plan view of a joint surface on the pump head side with the 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 relating to the arrangement of the seal member.

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

FIG. 13 is a plan view of the joint surface on the pump head side with the 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 Rotary shaft 18 Intake side cam shaft 24 Reed valve plate 26 Bellows 27 Cap 28 Flange 29 Pump room 33 Bellows guide 36 Collar part 37 Raceway ring 38 Rolling element 39 Raceway ring (swash plate) 43 Suction side reed valve operation space 44 Discharge side reed valve operation space 45 Suction port 46 Discharge port 47 Oil passage 49 Oil passage 52 Suction side reed valve 53 Discharge side lead 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

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Inouguchi Iwane 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (56) References JP-A-4-191461 (JP, A) JP-A-4- 358773 (JP, A) Japanese Utility Model Showa 60-183281 (JP, U) Japanese Utility Model Application 2-7385 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04B 1/16 F04B 43 / 08 F04B 53/10

Claims (5)

(57) [Claims] 1. A swash plate provided with a plurality of pump chambers and arranged on a circumference with their axes parallel to each other and swinging at one end of these pump chambers to change the volume of the pump chambers; One for each pump chamber at 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 alternately arranged in a pump chamber arrangement direction. . 2. A plurality of bellows constituting a pump chamber are provided,
Each of these bellows is arranged on the circumference while being parallel to each other, while a swash plate that swings to extend and contract the bellows at one end of the bellows and a pump chamber at the other end of the bellows are provided for each pump chamber. A fuel pump comprising one suction-side check valve and one discharge-side check valve, wherein the suction-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-like body. The pump chamber side member holding 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 joining surfaces of the port side member having the suction port and the discharge port. Fuel pump. 4. The fuel pump according to claim 3, wherein seal members are mounted on respective joining surfaces of the pump chamber side member and the port side member. 5. The fuel pump according to claim 3, wherein seal members are mounted on both sides of the reed valve plate.