JPH0719155A - Plunger pump - Google Patents

Abstract

PURPOSE:To prevent the mixing of a liquid medium and lubricating oil by an atmospheric air lead-in hole with a simple device. CONSTITUTION:With the reciprocating motion of a plunger 6, a liquid medium is pressurized in a pressure chamber 50 and discharged, and lubricating oil is led into the sliding part of a cylinder from a lubricating oil feed passage 9. The change of pressure caused by the reciprocating motion of the plunger 6 is suppressed by an atmospheric air lead-in hole, and the liquid medium and lubricating oil still moving are accumulated at collar parts and collected separately in recovery spaces for recovery. The contact and mixing of the liquid medium and lubricating oil are thereby prevented completely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plunger pump in which one end of a plunger comes into contact with a rotating cam so that the plunger reciprocates in a cylinder bore, and a fluid medium is pumped from a pressure chamber formed at the other end of the plunger. .

[0002]

2. Description of the Related Art A plunger pump has been proposed which realizes a pumping action by a plunger that reciprocates by contacting one end with a rotating swash plate. Such a plunger pump can be used as a fuel pump in a fuel system of an internal combustion engine. For example, Japanese Patent Laid-Open No. 5-44629 discloses a pump of this type. Hereinafter, description will be given with reference to FIG.

One end of the plunger 6b is always in contact with a disk (cam) 7 fixed to the rotating shaft 1 and rotating integrally with the disk spring 8 which urges the disk 7 through a tappet 6a. A pressure chamber 50 is formed at the other end of the plunger 6b, and the liquid medium is sent at a low pressure from the fuel supply port. The liquid medium is discharged at a high pressure to the outside of the pump (not shown) via the check ball 31 due to the change in the volume of the pressure chamber 50 due to the reciprocating movement of the plunger 6b which is interlocked with the rotation of the swash plate 7.

Lubricating oil is supplied from the lubricating oil supply passage 9 to the outer peripheral surfaces of the plunger 6b and the tappet 6a which reciprocate here. For this reason, the lubricating oil on the outer peripheral surface of the plunger 6b and the liquid medium leaked under pressure may move along the plunger 6b due to the pressure change generated by the reciprocating motion of the plunger 6b, and may be mixed. Therefore, as a countermeasure against this, an air pressure feeding member 70 that is rotationally driven by the same drive source (rotary shaft 1) as the disk 7 is provided between the lubricating oil supply port 9a on the outer peripheral surface of the tappet 6a and the pressure chamber 50. An air supply groove 76 for supplying air from the air pressure feeding member 70 is provided, and the mixing of the lubricating oil and the fluid medium is blocked by the flow of air supplied from the air supply groove 76 and passing through the air recovery hole 68 and the like.

[0005]

In the plunger pump having the above structure, the air pumping member is required to solve the problem that the liquid medium and the lubricating oil are mixed with each other, and the lubricating oil is consumed and the function thereof is deteriorated. Therefore, the size of the plunger pump body is increased, the structure is complicated, and since the pneumatic force is fed by the rotational force of the cam, there is a problem that power loss for moving the plunger occurs.

Therefore, an object of the present invention is to suppress the pressure change generated in the space due to the reciprocating motion of the plunger only by opening the space provided in the cylinder bore to the atmosphere,
It is to prevent contact and mixing of liquid medium and lubricating oil.

[0007]

As means for solving the above-mentioned problems, the present invention has one end of a plunger abutting against a cam rotating through a tappet, whereby the plunger reciprocates in a cylinder bore, and the plunger moves. In a plunger pump that pumps a liquid medium supplied from a liquid medium supply port in a pressure chamber formed between the other end and a cylinder bore, a lubricating oil that supplies a lubricating oil different from the liquid medium to the sliding surface of the tappet. A supply port is provided, and a cylinder bore intermediate the lubricating oil supply port and the pressure chamber is communicated with the atmosphere through an atmosphere introduction hole, and an opening of a communication passage for collecting lubricating oil on the tappet side and the pressure chamber side. A space having an opening of a communication passage for collecting the liquid medium.

[0008]

According to the above means, the tappet slides in the axial direction, the reciprocating motion of the tappet and the plunger occurs, and the volume of the space provided in the cylinder bore changes. However, the pressure change in the space is suppressed by the air introduction hole. Therefore, the liquid medium and the lubricating oil do not move over the respective recovery paths due to the bias due to the pressure change, and both contact and
No more mixing.

[0009]

The first embodiment of the present invention will be described below. The first embodiment is an application of the present invention to a fuel injection pump for an internal combustion engine. FIG. 1 schematically shows a cross section of the plunger pump of the first embodiment. 2 to 9
2 is a detailed sectional view and side view according to the first embodiment. The rotary shaft 1 is rotatably supported by the pump body 2 via ball bearings 3 and 4, and is driven by power (not shown) such as an engine crankshaft. At one end of the rotary shaft 1 on the pump body 2 side, a disc 7 is formed concentrically with the rotary shaft. On one of the end faces in the axial direction of the disk 7, an inclined surface 7a that is slightly inclined with respect to the axis of the rotating shaft 1 is formed.

Inside the pump main body 2, a first cylinder bore 12a, a space 17, a second cylinder bore 12b, a space 13 and a third cylinder bore 12c are formed coaxially in parallel with the rotary shaft 1 in the order closer to the disk 7. . In this embodiment,
In the pump body 2, the cylinder bores 12a, 12b, 1
Five sets of 2c and spaces 13, 17 are formed at equal intervals in the circumferential direction of the rotary shaft 1. The tappet 5 is slidably inserted into the first cylinder bore 12a. The plunger 6 is attached to the second cylinder bore 12b and the third cylinder bore 12c.
Is slidably inserted, and the plunger 6 is disposed so as to penetrate through the second cylinder bore 12b and the spaces 13 and 17. The plunger 6 is urged toward the disk 7 side by a coil spring 8 whose both ends are supported by the pump body 2 and the disk 7 side end of the plunger 6. Therefore, the tappet 5 is urged by the end of the plunger 6 on the side of the disk 7 so as to always contact the disk 7. Due to this sliding, the lubricating oil supply passage 9 is formed on the inner circumference of the first cylinder bore 12a.
Of the lubricating oil supply passage 9 is open at one end of
(FIG. 4). Lubricating oil is supplied to the oil supply port 39 from an oil pump (not shown). Also the third
A pressure chamber 50 is formed at the tip of the plunger 6 fitted in the cylinder bore 12c, and the low pressure fuel is supplied from the fuel supply port 40 through the fuel supply passage 10 and the annular groove 49 (FIG. 3). Plunger 6 supplied to chamber 50
The fuel pumped by the reciprocating motion of the check ball 3
1 through the fuel discharge path 11 and is discharged from a discharge port 42 (FIG. 4) to a fuel injection nozzle (not shown).

Atmosphere introduction capable of introducing atmosphere into a space 17 having a cylindrical shape for collecting lubricating oil provided between the first cylinder bore 12a and the second cylinder bore 12b and having a diameter larger than that of the first cylinder bore 12a and the second cylinder bore 12b. Lubricating oil recovery passage 1 for collecting lubricating oil from hole 21 and lubricating oil supply passage 9
One end of 9 is opened. Also, the second cylinder bore 12
b and the third cylinder bore 12c, the same atmosphere introducing hole 20 and the same leaking fuel are collected in the cylindrical space 13 for collecting the leaking fuel and having a diameter larger than the second cylinder bore 12b and the third cylinder bore 12c. One end of the fuel recovery passage 15 is opened. Further, as can be seen by referring to FIGS. 7 and 8, the atmosphere introduction holes 20 and 21 (the communication passages 57, 58, 59, 60, 61, 73, 74 by the annular passages 56, 70,
Connected to 75, 76, 77. ) Is preferably opened at a position above when mounted. Plunger 6 has
In order to stop the movement of the fuel through the plunger 6, the collar portions 18 and 14 are provided so as not to hinder the movement of the plunger corresponding to the space 17 for collecting the lubricating oil and the space 13 for collecting the fuel.

FIGS. 2 and 4 are side views of the plunger pump after assembly, which are fixed by bolts 43, and have a lubricating oil external supply port 39, a fuel external supply port 40 and a fuel recovery port 41. Is open to connect with the outside. 5 and 9 are cross-sectional views of the plunger pump before assembling and the positioning pins 46 and 47 are provided.
Is provided. 6, FIG. 7 and FIG. 8 are sectional views of the designated position in FIG. 3 and substantially correspond to FIG. The atmosphere introduction hole 21 of FIG. 1 is provided with 73, 74, 75, 76, 7 of FIG.
7, the lubricating oil recovery passage 19 of FIG. 1 is connected to 65, 66, 67, 68, 69 of FIG. 6, and similarly, the atmosphere introduction hole 20 is 57, 58 of FIG. 59, 60, 6
First, the fuel recovery passage 15 is provided with 51, 52, 53, 5 in FIG.
It is connected to 4, 55. Further, the lubricating oil recovery hole 19 (which is connected to the communication passages 65, 66, 67, 68, 69 by the annular passage 70) and the fuel recovery hole 15 (the communication passages 51, 52, 53, 54, 55 by the annular passage 56) are connected. Is preferably provided below the center of each plunger so that the lubricating oil and fuel can be recovered by gravity.

Therefore, the pressure change generated in the space 17 for collecting the lubricating oil and the space 13 for collecting the leaked fuel is suppressed by opening the atmosphere introducing holes 20 and 21 to the atmosphere. As a result, the movement of the lubricating oil and the fuel through the second cylinder bore 12b is suppressed, and the lubricating oil and the fuel are separately collected by the lubricating oil recovery passage 19 and the fuel recovery passage 15 before the contact between the lubricating oil and the fuel. Further, the collar portion 18 is provided to stop the movement of the lubricating oil transmitted through the tappet 5.

When the disc 7 is rotated by the rotating shaft 1,
Inclined surface 7 where the plunger 6 becomes thinner in the axial direction
When contacting a, the plunger 6 moves to the coil spring 8
When the plunger 6 comes into contact with the inclined surface 7a where the thickness of the disk 7 increases, the plunger 6 moves to the left in the figure.
Moves to the right in the figure against the coil spring 8. When the plunger 6 comes to a position where the opening 10a communicates with the pressure chamber 50, the low-pressure medium is sucked into the pressure chamber 50 through the opening 10a. When the plunger moves to the right in the figure, after the opening 10a is closed, the medium in the pressure chamber 50 is compressed by the plunger 26, and the pressure of the medium pushes the check ball 31 against the spring 31a. It is opened and the liquid medium is pumped. The lubricating oil and the fuel, the movements of which are suppressed in this process, move along the plunger 6 and the tappet 5 in a small amount. The small amounts of lubricating oil and fuel are stopped from moving by the collar portions 14 and 18, and drip from the collar portions 14 and 18 into the spaces 13 and 17, and are collected by the recovery passages 15 and 19 provided in the spaces 13 and 17, respectively. Be recovered.

Next, a second embodiment will be described with reference to FIGS. 10, 11 and 12. The direction of the force between the disk (not shown) and the plunger 6 in FIG. 10 is orthogonal to the inclined surface (not shown) via the tappet (not shown), and the inclined surface and the axis 81 of the plunger 6 are inclined with respect to each other.
Due to the force perpendicular to the inclined surface from the disk, the plunger 6 is not limited to the force in the direction of its axis 81, but also the coaxial line 8
A force (lateral pressure) in the direction orthogonal to 1 is applied. Therefore, the third cylinder bore 12c of the plunger 6, which is directly involved in pressurization
When the edge portion 84 of the tip fitted in the guide portion A does not have the guide portion A, there is a possibility that the side pressure is directly applied to the edge portion 84 to cause contact and wear to increase fuel leakage. However, when the guide portion A that does not hinder the suction of the liquid medium is provided in the plunger tip portion 84, the guide portions 22 and 23 receive the lateral pressure,
In order to protect the wear of the portion 84 directly related to the pressurization,
There is no risk of uneven wear of the plunger and an increase in the amount of liquid medium leaking from the sliding surface. Further, in order to prevent wear of the cylinder bore 12c, the TIN-treated half sleeve B is press-fitted as shown in FIG.
When the IN treatment is applied, the plunger 6 and the cylinder bore 1
(2) Uneven wear can be prevented, leakage of the liquid medium can be minimized, and increase in the amount of leakage can be suppressed. Although a half sleeve is used here, a tubular sleeve may be used as long as the TIN process can be performed.

[0016]

EFFECT OF THE INVENTION Since the air pressure feeding portion which is required in the conventional device is not required and no power is required, the plunger pump main body can be downsized and simplified. Furthermore, the pressure change generated by the reciprocating motion of the plunger is suppressed by the air introduction hole,
The movement of the fluid medium and the lubricating oil is suppressed, and since the lubricating oil is not mixed with the fluid medium, the consumption of the lubricating oil is eliminated. In addition, it is possible to prevent the reduction of the lubrication effect due to the mixing of the fluid medium with the lubricating oil as in the conventional case, and maintain the good lubricity.

[Brief description of drawings]

FIG. 1 is a schematic view of a cross section of a plunger pump according to a first embodiment of the present invention.

FIG. 2 is a side view of the plunger pump according to the first embodiment of the present invention on the rotating shaft side.

FIG. 3 is a sectional view of the plunger pump according to the first embodiment of the present invention.

FIG. 4 is a side view on the discharge port side of the plunger pump according to the first embodiment of the present invention.

5 is a cross-sectional view taken along the line I-I of FIG.

6 is a cross-sectional view taken along the line II-II of FIG.

7 is a cross-sectional view taken along the line III-III in FIG.

8 is a cross-sectional view taken along the line IV-IV in FIG.

9 is a cross-sectional view taken along the line VV of FIG.

FIG. 10 is a sectional view of a plunger provided with a guide portion according to a second embodiment of the present invention.

FIG. 11 is a transverse sectional view of a plunger pump using a plunger provided with a guide portion according to a second embodiment of the present invention.

FIG. 12 is a cross-sectional view of a plunger pump according to a second embodiment of the present invention, in which a half sleeve and a plunger are subjected to TIN treatment.

FIG. 13 is a sectional view showing an example of a conventional plunger pump.

[Explanation of symbols]

 1 ... Rotating shaft 2 ... Pump body 3, 4 ... Ball bearing 5 ... Tappet 6 ... Plunger 7 ... Disc (cam) 8, 31a ... Coil spring 12a ... -First cylinder bore 12b ... Second cylinder bore 12c ... Third cylinder bore 13, 17 ... Recovery space 14, 18 ... Collar portion 50 ... Pressure chamber A ... Guide portion B ... Half sleeve

Claims (1)

[Claims] 1. A tappet is formed between the other end of the plunger and the cylinder bore by abutting the tappet on one end of a plunger mounted in a cylinder in the pump body and driving the tappet in the axial direction of the plunger by a cam. In the plunger chamber that pressure-feeds the liquid medium supplied from the liquid medium supply port in the pressure chamber, a lubricating oil supply port that supplies a lubricating oil different from the liquid medium to the sliding surface of the tappet with the cylinder bore is provided, A cylinder bore intermediate the lubricating oil supply port and the pressure chamber is in communication with the atmosphere through an air introduction hole, and a liquid medium is recovered in the opening of the communication passage for recovering the lubricating oil in the tappet side and in the pressure chamber side. A plunger pump having a space having an opening of a communication passage.