JPH09324747A - Axial plunger pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the flow in of an operation liquid around the drive shaft support part in a housing and operate constitution parts smoothly. SOLUTION: A swash plate 16 is installed on the end of a drive shaft 13 and a cylinder block 11 is arranged on a position facing to the swash plate 16 in a housing 6. An auxiliary plate 38 is installed to the swash plate 16 relatively and rotatably and a plunger 19 is push-pressed through this auxiliary plate 38. A welded bellows 45 for partitioning the inside of the housing 6 to an operation liquid room 48 and a lubrication liquid room 49, while surrounding the drive shaft 13 is arranged between the auxiliary plate 38 and the housing 6. A filter 55 is interposed between the drive shaft 13 and the welded bellows 45. As the periphery area of the drive shaft 13 is partitioned by the welded bellows 45, the operation liquid is not streamed in the drive shaft 13 and its support part. As the foreign material like the worn powder generated in the support part of the drive shaft 13 is caught by the filter 55, the entering to the clearance of the welded bellows 55 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial plunger pump used for a fuel pressurizing pump or the like of a fuel injection device of an automobile, and more particularly to an axial plunger pump in which a drive shaft supporting portion in a housing is enhanced in lubricating performance.

[0002]

2. Description of the Related Art As an axial plunger pump, there is a structure in which a swash plate is integrally provided at an end of a drive shaft, and a cylinder block is fixedly provided in a housing at a position facing the swash plate. In this axial plunger pump, when the swash plate oscillates as the drive shaft rotates, a plurality of plungers on the cylinder block facing the swash plate are sequentially pressed by the swash plate to repeatedly project and retract, and each plunger is The hydraulic fluid sucked into the cylinder hole from the suction passage when projecting is sent out to the discharge passage when the plunger retreats (actual opening 2-92).
No. 073).

By the way, this type of axial plunger pump has come to be used as a fuel pressurizing pump of a fuel injection device of an automobile in recent years. But,
When the axial plunger pump is used in such applications, low-viscosity hydraulic fluid such as gasoline that is sucked and discharged in the cylinder block leaks into the peripheral area of the drive shaft support inside the housing, It is conceivable that the lubrication performance of the bearings and seal parts in the region will deteriorate.

To cope with this, an axial plunger pump as described in Japanese Patent Application No. 7-342693 previously filed by the present applicant has been devised.

In this axial plunger pump, an auxiliary plate is attached to the end surface of the swash plate on the cylinder block side so as to be relatively rotatable, and a drive shaft is surrounded between the auxiliary plate and the housing to form a hydraulic fluid chamber in the housing. A welding bellows is provided so as to be separated from the lubricating liquid chamber, and the lubricating liquid chamber separated by the welding bellows is filled with a relatively high-viscosity lubricating liquid. According to this pump, since the peripheral areas of the drive shaft and the drive shaft supporting portion are always filled with the relatively high-viscosity lubricating liquid, there is no problem that the lubrication performance of the bearings and seal parts in the peripheral area of the drive shaft deteriorates. .

[0006]

However, in the above-mentioned axial plunger pump, since the inside of the housing is divided into the working fluid chamber and the lubricating fluid chamber by the welding bellows, as shown in FIG. When a foreign substance a such as abrasion powder generated in the shaft support portion or the like enters a very small gap between the bellows elements of the welding bellows 80, the foreign substance a
Therefore, there is another problem that the smooth operation of the bellows 80 is hindered.

Therefore, the present invention is intended to provide an axial plunger pump capable of surely preventing the working fluid from flowing into the peripheral region of the drive shaft and maintaining the smooth operation of the components. .

[0008]

As a means for solving the above-mentioned problems, the present invention provides a swash plate fixed to the end of a drive shaft rotatably supported in a housing.
A cylinder block, which holds a plurality of plungers so as to be movable back and forth along the axial direction, is fixedly provided in the housing at a position facing the swash plate, and the plurality of plungers are sequentially pressed by the rotation of the swash plate. In the axial plunger pump that discharges the hydraulic fluid sucked from the suction passage to the discharge passage, an auxiliary plate is attached to the end surface of the swash plate on the cylinder block side so as to be relatively rotatable, and a drive shaft is provided between the auxiliary plate and the housing. A welding bellows which surrounds the housing and separates the working fluid chamber and the lubricating fluid chamber is provided, and a filter is provided between the welding bellows and the drive shaft. The lubricating fluid chamber in the peripheral region of the drive shaft is completely separated from the hydraulic fluid chamber by the cooperation of the auxiliary plate and the welding bellows. In addition, foreign matter such as abrasion powder generated in the drive shaft support portion and the like is reliably captured by the filter and does not enter the gap between the bellows elements of the welded bellows.

The filter may be fixed to either the housing or the auxiliary plate. In this case, the structure of the filter itself can be simplified and the assembling can be facilitated.

Further, the filter may be formed of a flexible material, and both ends of the filter may be fixed to the housing and the auxiliary plate. In this case, it is possible to completely block the foreign matter, which tends to enter the gap of the welding bellows from the drive shaft side, with the filter.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

In this embodiment, the axial plunger pump 1 according to the present invention is applied to a fuel pressurizing pump of a fuel injection system for an automobile, and as shown in FIG. Fuel (working fluid) such as gasoline, which has been supplied in a low pressure state via the, is pressurized to a predetermined pressure by the axial plunger pump 1 and supplied to the injector 4, and the fuel is injected into the injector 4.
The fuel is injected into the cylinder (not shown) of the engine and the excess fuel is returned from the injector 4 to the suction passage 5 of the pump 1.

In this axial plunger pump 1, the housing 6 has a housing body 8 having a recess 7 for accommodating components, and a front cover 9 attached to the front end thereof.
The valve block 10 and the cylinder block 11 are joined together by bolts 12 in the recess 7 of the housing body 8 in a superposed state. A drive shaft 13 is supported by the front cover 9 via radial bearings 14 and 15 composed of needle bearings and metal bearings, and the drive shaft 13 is provided at its end facing the inside of the housing 6. A swash plate 16 having an end surface inclined at a predetermined angle with respect to the axis is integrally formed, and a cup for coupling with a camshaft (not shown) of the engine is provided at an end portion of the housing 6 on the side projecting to the outside. A ring 17 is provided.

The cylinder block 11 is formed with a plurality of cylinder holes 18 along the axial direction at equal intervals in the circumferential direction. In each of the cylinder holes 18, a plunger 19 spring-biased in the direction of the swash plate 16 is formed. Is housed so that it can move back and forth. A hemispherical recess 20 is formed on the top surface of each plunger 19, and a shoe 21 described later is rotatably fitted in the recess 20.

A plurality of suction ports 22 and a discharge port 23 communicating with each cylinder hole 18 of the cylinder block 11 are formed in the valve block 10 on the back side of the cylinder block 11, and each suction port 22 is connected to each suction port 22. Is provided with a suction check valve 24, and each discharge port 23 is provided with a discharge check valve 25. All the suction ports 22 are communicated with a suction side annular groove 26 formed in the housing body 8 on the back surface of the valve block 10, and are communicated with the suction passage 5 of the housing body 8 through the annular groove 26. On the other hand, all the discharge ports 23 described above communicate with the discharge side annular groove 27 formed on the outer circumference of the valve block 10, and the annular groove 2
7 to communicate with the discharge passage 28 of the housing body 8. Therefore, each plunger 19 is attached to the cylinder hole 18
When it moves forward and backward inside, the working fluid is sucked into each cylinder hole 18 through the suction side annular groove 26, and the working fluid is sent out to the discharge passage 28 through the discharge side annular groove 27.

Reference numeral 29 in the drawing is a low pressure regulator provided between the suction pipe connection port (not shown) of the suction passage 5 and the suction side annular groove 26 to maintain the suction pressure at a constant low pressure. , Drain port 30 of this low pressure regulator 29
Communicate with the fuel tank 2 through a return pipe 31. Further, in FIG. 2, 36 is an accumulator for preventing pulse pressure connected to the discharge side annular groove 27, 37 is a discharge pressure sensor, and 34 is a high pressure regulator.

On the other hand, a disk-shaped auxiliary plate 38 is attached to the end surface of the swash plate 16 formed on the drive shaft 13 so as to be relatively rotatable. A boss 39 is provided at the center of the auxiliary plate 38, and the boss 39 is fitted into a support hole 40 formed at the center of the end face of the swash plate 16 so as to be relatively rotatable. A thrust plate 41 having a high hardness and a small friction coefficient is rotatably attached to the end surface of the auxiliary plate 38 on the cylinder block 11 side by a bolt 42, and the thrust plate 41 is fitted to each plunger 19 described above. The shoe 21 is slidably abutted. Since each plunger 19 is biased by the spring in the direction of the swash plate 16 as described above, each shoe 21 is constantly pressed against the thrust plate 41 by the biasing force of the plunger 19. Further, a load supporting flange 43 is provided at a rear position of the swash plate 16 of the front cover 9, and the load supporting flange 43 is provided.
Between the swash plate 16 and the swash plate 16, and between the swash plate 16 and the auxiliary plate 38, a thrust bearing 44 composed of a needle bearing.
a and 44b are interposed. This thrust bearing 44
Reference characters a and 44b are for causing the load supporting flange 43 of the front cover 9 to support the axial component of the reaction force received by the auxiliary plate 38 from the plunger 19, and the radial component of the reaction force received from the plunger 19 is The boss 39 of the auxiliary plate 38 and the support hole 40 of the drive shaft 13 are supported by a fitting portion.

A well-known welded bellows 45, which is formed by joining a plurality of annular metal plates, is joined to the outer peripheral edge of the auxiliary plate 38 in a hermetically sealed state. From the peripheral area to the peripheral area of the swash plate 16 are covered. The other end of the welded bellows 45 is also hermetically joined to an annular mounting flange 46, and the outer peripheral edge portion of the mounting flange 46 is interposed between the joint portion of the housing body 8 and the front cover 9. The front cover 9 with the bolt 47.
Together with this, it is connected to the housing body 8. The welding bellows 45 divides the inside of the housing 6 into an outer working fluid chamber 48 and an inner lubricating fluid chamber 49.
The inside is filled with the hydraulic fluid (fuel) leaking from the cylinder block 11, and the inside of the lubricating liquid chamber 49 is filled with the lubricating liquid having a relatively high viscosity.

Here, as shown in FIG. 3, a metallic filter 55 axially extending from the mounting flange 46 along the inner peripheral surface of the welding bellows 45 is provided on the inner peripheral portion of the mounting flange 46. It is fitted and fixed. This filter 5
5 is a housing 6 in the state of being unitized with a mounting flange 46, an auxiliary plate 38, a welding bellows 45, etc.
As shown in FIG. 1, the drive shaft 13 is installed in the housing 6 in this manner.
And the welded bellows 45. The filter 55 has a predetermined gap with the auxiliary plate 38 in the assembled state so as not to interfere with the auxiliary plate 38 when the auxiliary plate 38 tilts.

Reference numeral 50 in the figure denotes an oil seal provided adjacent to the radial bearing 14 that supports the drive shaft 13. The oil seal 50 and the radial bearing 14 have a load support flange 43 of the front cover 9. The lubricating liquid is surely introduced through the introduction hole 51 formed in. The swash plate connecting corner portion of the drive shaft 13 is formed with an introduction hole 52 that connects the bottom portion of the support hole 40 of the swash plate 16 and the peripheral space of the drive shaft 13 to each other.
Through this, the lubricating liquid can be introduced also into the fitting gap between the support hole 40 and the boss 39 of the auxiliary plate 38. Reference numeral 53 in the drawing denotes a return passage for returning the hydraulic fluid leaking into the recess 7 (the hydraulic fluid chamber 48) of the housing body 8 to the fuel tank 2.

In the above structure, when the drive shaft 13 rotates with the start of the engine, the swash plate 16 integral with the drive shaft 13 rotates, whereby the auxiliary plate 38 is blocked by the bellows 45 from rotating. While swinging relative to the plate 16, it swings (swings) integrally with the swash plate 16. When the auxiliary plate 38 swings in this way, the plunger 19 on the cylinder block 11 repeats the forward / backward movement in sequence via the thrust plate 41 and the shoe 21 slidingly contacting the thrust plate 41, so that the pump action is continuously performed. . At this time, the suction passage 5 from the fuel tank 2 via the supply pump 3
The hydraulic fluid supplied to the cylinder is regulated to a set low pressure by a low pressure regulator 29 in the middle of the passage, and then sucked into the cylinder hole 18 through the suction side annular groove 26, the suction port 22, and the suction check valve 24 in this order. , Here Plunger 1
After being pressurized by 9, the fuel is supplied to the injector 4 from the cylinder hole 18 through the discharge check valve 25, the discharge port 23, the discharge side annular groove 27, and the discharge passage 28 in order. Then, the surplus of the hydraulic fluid used in the injector 4 is returned to the suction passage 5.

Thus, the axial plunger pump 1
If the operation is continued, hydraulic fluid will leak into the recess 7 of the housing body 8 through the gap between the cylinder block 11 and the valve block 10, the sliding gap between the cylinder hole 18 and the plunger 19, etc. Since the inside of the recess 7 is completely sealed by the auxiliary plate 38 and the welding bellows 45 into the working fluid chamber 48 and the lubricating fluid chamber 49,
The low-viscosity hydraulic fluid (fuel) does not enter the bearings 14, 15, 44a, 44b around the drive shaft 13 and the oil seal 50. The lubricating liquid chamber 49 is filled with a relatively high-viscosity lubricating liquid, and the bearings 14, 15, 44a,
Since this lubricating liquid is always spread over the 44b and the oil seal 50, the bearings 14, 15, 44a, 44
b and the oil seal 50 can maintain the initial performance for a long period of time.

When the operation of the axial plunger pump 1 is continued, foreign matter such as abrasion powder may be generated from the peripheral region of the drive shaft 13 in the lubricating liquid chamber 49.
Since the filter 55 is disposed between the welding bellows 45 and the welding bellows 3 so as to cover almost the entire area of the welding bellows 45 in the axial direction, foreign matter generated in the peripheral region of the drive shaft 13 as shown in FIG. The a is reliably captured by the filter 55 and does not enter the gap between the bellows elements of the welded bellows 45. Therefore, in this pump 1,
The malfunction of the welding bellows 45 due to the biting of the foreign matter a does not occur.

Further, in this axial plunger pump 1, one end side of the metallic filter 55 is fitted and fixed to the mounting flange 46 and the other end side is not fixed to the auxiliary plate 38, but is in a free end state. The structure of the filter 55 itself is simple, and the assembling work of the filter 55 is easy, so that the filter 55 can be manufactured at low cost.

The embodiment of the present invention is not limited to the one described above. For example, the filter 55 is formed of a flexible resin or the like which can follow the deformation of the bellows 45, and the filter is formed. Both ends of 55 may be fixed to the mounting flange 46 (housing) and the auxiliary plate 38. In this case, the gap between the filter 55 and the auxiliary plate 38 is eliminated, so that the filter 55 can more reliably block foreign substances that try to enter the gap of the welding flange 45.

[0026]

As described above, according to the present invention, the auxiliary plate is attached to the end surface of the swash plate on the cylinder block side so as to be relatively rotatable, and the drive shaft is surrounded between the auxiliary plate and the housing to operate in the housing. Since a flexible partitioning member that separates the liquid chamber and the lubricating liquid chamber is provided and a filter is provided between the welding bellows and the drive shaft, a low-viscosity hydraulic fluid is generated in the peripheral region of the drive shaft support portion. It is possible to reliably prevent the inflow, and it is possible to prevent foreign matter such as abrasion powder generated in the drive shaft support portion or the like from being caught in the welding bellows. Therefore, according to the present invention, the lubrication performance around the drive shaft can be reliably improved, and the smooth operation of the welding bellows can be maintained for a long period of time.

When the filter is fixed to either the housing or the auxiliary plate, the structure of the filter itself is simplified and the assembly is easy, and as a result, the manufacturing cost can be reduced. become.

Furthermore, when the filter is made of a flexible material, and both ends of the filter are fixed to the housing and the auxiliary plate, foreign matters that try to enter the gap of the welding bellows from the drive shaft side are filtered by the filter. It can be shut off more completely.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1 showing the same embodiment.

FIG. 3 is a sectional view of a component showing the same embodiment.

FIG. 4 is an enlarged cross-sectional view showing the same embodiment.

FIG. 5 is an enlarged cross-sectional view showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Axial plunger pump, 5 ... Suction passage, 6 ... Housing, 11 ... Cylinder block, 13 ... Drive shaft, 16 ... Swash plate, 19 ... Plunger, 28 ... Discharge passage, 38 ... Auxiliary plate, 45 ... Welding bellows, 48 ... Working fluid chamber, 49 ... Lubricating fluid chamber, 55 ... Filter.

Claims (3)

[Claims] 1. A cylinder block, wherein a swash plate is fixedly attached to an end of a drive shaft rotatably supported in a housing, and a plurality of plungers are movably held in an axial direction. An axial plunger pump fixedly provided at a position facing the swash plate in the housing, wherein the plurality of plungers are sequentially pressed by the rotation of the swash plate to send the working fluid sucked from the suction passage to the discharge passage, A welding bellows is attached to the end surface of the swash plate on the cylinder block side so that relative rotation is possible, and a drive shaft is surrounded between the auxiliary plate and the housing to separate the inside of the housing into a working fluid chamber and a lubricating fluid chamber. And an axial plunger pump characterized in that a filter is provided between the welding bellows and the drive shaft. 2. The axial plunger pump according to claim 1, wherein the filter is fixed to either the housing or the auxiliary plate. 3. The axial plunger pump according to claim 1, wherein the filter is made of a flexible material, and both ends of the filter are fixed to the housing and the auxiliary plate.