CN107559185B

CN107559185B - Plunger pump and plunger for supplying fuel

Info

Publication number: CN107559185B
Application number: CN201610511603.7A
Authority: CN
Inventors: 马谦; 成小磊; 周奇
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2016-06-30
Filing date: 2016-06-30
Publication date: 2021-01-12
Anticipated expiration: 2036-06-30
Also published as: CN107559185A

Abstract

The invention relates to a plunger (1) which is used for reciprocating in a plunger sleeve (2), wherein one or more sealing structures (10) are arranged on the plunger (1), the sealing structures (10) are one or more recesses (11) recessed towards the plunger (1), the contour line of the recess (11) comprises an upper intersection point A and a lower intersection point B which intersect with the plunger sleeve (2), the farthest distance from the plunger sleeve (2) on the contour line is a far dead point C, and the far dead point C is positioned below the perpendicular bisector of the upper intersection point A and the lower intersection point B. The invention can enhance the sealing effect between the plunger and the plunger sleeve.

Description

Plunger pump and plunger for supplying fuel

Technical Field

The invention relates to a plunger pump for supplying fuel and a plunger thereof, in particular to a plunger pump with a plunger having a good sealing effect and a plunger thereof.

Background

The plunger pump is one of high-pressure pumps, and has a wide application range in the industrial field. The plunger of the plunger pump makes linear reciprocating motion in the plunger sleeve through the transmission mechanism to pressurize fluid in the plunger pump. In order to keep the free sliding between the plunger and the plunger sleeve and avoid the situation that the plunger and the plunger sleeve are heated during movement and are not blocked after being deformed by high pressure, the clearance between the plunger and the plunger sleeve is necessary. However, because the plunger, when pressurized, causes a differential pressure between the area at the lower end of the plunger and the area at the upper end of the plunger, the fluid in the high pressure region has a tendency to flow toward the low pressure region. The presence of the gap causes fuel to leak from the high pressure region to the low pressure region.

Referring to fig. 1 and 2, a conventional plunger 100 is provided with a sealing structure 101, the sealing structure 101 is a groove 102 recessed toward the plunger 100, and the groove 102 has a symmetrical structure. In practical use, as shown in fig. 3, due to the pressure difference and other factors, the pressure above the plunger 100 is higher, so that the fluid in the high-pressure area enters the groove 102 and continues to be injected downwards through the groove 102 into the area below the groove 102, which is normally a lubricating oil cavity with lower pressure, therefore, the leakage at the groove 102 will make the sealing effect between the plunger and the plunger sleeve poor, and the leakage of the fluid above the plunger 100 will make the plunger pressurizing effect weaker.

It is therefore desirable to design a new type of structure to enhance the seal between the plunger and the plunger barrel.

Disclosure of Invention

The invention aims to provide a plunger pump with better sealing effect and a plunger thereof.

The invention provides a plunger of a plunger pump for supplying fuel, which is used for reciprocating in a plunger sleeve and is provided with one or more sealing structures, wherein the sealing structures are one or more depressions inwards towards the plunger, the contour line of the depressions comprises an upper intersection point A and a lower intersection point B which are intersected with the plunger sleeve, the farthest distance from the plunger sleeve on the contour line is a far dead point C, and the far dead point C is positioned below a perpendicular bisector of the upper intersection point A and the lower intersection point B.

Preferably, the upper intersection point a is close to a high-pressure region in the plunger barrel, the lower intersection point B is close to a low-pressure region in the plunger barrel, and the position of the far dead center C is lower than the lower intersection point B.

Preferably, the contour line is a smooth curve, more preferably in the shape of an eagle hook.

Preferably, the contour lines are polylines.

The invention also provides a plunger pump for supplying fuel, comprising a pump housing, a plunger sleeve arranged in the pump housing, and a plunger arranged in the plunger sleeve and reciprocating along the plunger sleeve, wherein the plunger has the characteristics as described above.

Preferably, the plunger pump further comprises a lubricating oil cavity, the lubricating oil cavity is lubricated by oil, the pressure of the lubricating oil cavity is lower than the pressure above the plunger, and the upper intersection point a is far away from the lubricating oil cavity than the lower intersection point B.

By using the structural characteristics of the invention, because the far dead point of the contour line of the depression on the plunger is lower than the perpendicular bisector of the upper and lower intersection points, compared with the traditional design, the trend of stronger vortex backflow is formed when the upper fluid enters the depression, and the sealing effect between the plunger and the plunger sleeve can be effectively improved.

Drawings

Exemplary embodiments of the present invention will be described in detail below with reference to the attached drawings, it being understood that the embodiments described below are merely illustrative of the present invention and do not limit the scope of the present invention, wherein:

FIG. 1 is a schematic diagram of a prior art plunger to show the overall structure of the plunger;

FIG. 2 is an enlarged view of a portion of the plunger of FIG. 1 to show the configuration of the recess;

FIG. 3 is a schematic view of the recess shown in FIG. 2 as fluid enters the recess to show the direction of flow of the fluid;

FIG. 4 is a schematic structural view of one embodiment of the plunger pump of the present invention;

FIG. 5 is a schematic structural view of one embodiment of the plunger of the present invention to show the overall structure of the plunger;

FIG. 6 is an enlarged partial view of the depression shown in FIG. 5;

FIG. 7 is the recess shown in FIG. 6 to show the direction of fluid flow as it fills the recess;

FIG. 8 is an enlarged partial view of another embodiment of the plunger of the present invention;

fig. 9 is an enlarged partial view of yet another embodiment of the plunger of the present invention.

Detailed Description

In different drawings, the same or similar components are denoted by the same reference numerals.

It is to be understood that the drawings are designed solely for purposes of illustration and that no limitation on the invention is intended in the form of the details of construction and the arrangement of the components set forth in the drawings.

Referring to fig. 4, the plunger pump 3 for supplying fuel according to the present invention includes a pump housing 4, a lubricating oil chamber 30 is provided in the plunger pump 3, and a transmission mechanism is provided in the lubricating oil chamber 30, and generally, the pressure in the lubricating oil chamber 30 is relatively low and is far lower than the high-pressure region above the plunger 1, which is the low-pressure region. A plunger sleeve 2 is also arranged in the plunger pump 3, a plunger 1 is arranged in the plunger sleeve 2, and the plunger 1 is driven by a transmission mechanism to reciprocate in the plunger sleeve 2. The lubricating oil in the lubricating oil chamber 30 can be diesel oil or engine oil.

With continued reference to fig. 5-7, a plurality of sealing structures 10 are provided on the plunger 1, although in other embodiments, one sealing structure 10 may be provided. The sealing structure 10 is a recess 11 recessed towards the plunger 1, and in other embodiments, the recess 11 may be provided in a plurality in series. Specifically, the contour line of the recess 11 includes an upper intersection point a and a lower intersection point B intersecting the plunger barrel 2. In the present embodiment, the upper intersection point a is farther from the low pressure region, i.e., the lubricating oil chamber 30, than the lower intersection point B. The point on the contour line farthest from the plunger barrel 2 is a far-end point C that is located below the perpendicular bisector of the upper intersection point a and the lower intersection point B. Preferably, the distal point C is slightly lower than the lower intersection point B, and the contour line is preferably a smooth curve, and the overall contour line is preferably in the shape of an eagle hook or a fishhook as a whole. As shown in fig. 7, in practical use, when the pressure above the plunger 1 is higher, the fluid enters the recess 11 under the action of the pressure difference, and the far dead center C is located below the perpendicular bisector between the upper intersection point a and the lower intersection point B, so that the fluid has a tendency of returning to form a vortex after flowing through the far dead center C, and thus the fluid is less injected into the lower part of the recess 11. Thereby increasing the sealing effect between the plunger 1 and the plunger barrel 2.

Referring to fig. 8 to 9, embodiments of a sealing structure 10 of the plunger 1 different from those shown in fig. 5 and 7 are shown. The sealing structure 10 shown in fig. 8 comprises a plurality of consecutive recesses 11. In fig. 9, the contour line of the depression 11 may be a broken line. Those skilled in the art will appreciate that the seal and recess associated with the present invention may take a variety of forms.

The invention has been described in connection with only the presently preferred embodiment considered to be the most practical and preferred embodiment, and it is to be understood that the above description is not intended to limit the invention, nor is the invention limited to the above examples, but rather, is intended to cover within the spirit and scope of the invention variations, modifications, additions and substitutions that may be made by those skilled in the art.

Claims

1. A plunger (1) of a plunger pump for supplying fuel, intended to reciprocate in a plunger barrel (2), said plunger (1) being provided with one or more sealing structures (10), characterized in that said sealing structures (10) are one or more recesses (11) recessed towards the plunger (1), said recesses (11) having, on a contour line, an upper point of intersection a and a lower point of intersection B with the plunger barrel (2), said contour line being furthest from the plunger barrel (2) a far point of intersection C, said far point of intersection C being below a mid-perpendicular to said upper point of intersection a and said lower point of intersection B, such that fluid entering said recesses (11) under the effect of a pressure difference has a tendency to flow back into vortices after passing said far point of intersection C.

2. Plunger (1) of a plunger pump for feeding fuel according to claim 1, characterized in that said upper point of intersection a is close to the high pressure area in the plunger barrel (2) and said lower point of intersection B is close to the low pressure area in the plunger barrel (2).

3. Plunger (1) of a plunger pump for supplying fuel according to claim 1 or 2, characterised in that the position of the far dead centre C is below the lower intersection point B.

4. Plunger (1) for a fuel-filling plunger pump according to claim 1 or 2, characterized in that the contour is a smooth curve.

5. Plunger (1) of a plunger pump for supplying fuel according to claim 4, characterized in that the contour is eagle-hook shaped.

6. Plunger (1) for a fuel-filling plunger pump according to claim 1 or 2, characterized in that the contour is a broken line.

7. A plunger pump (3) for supplying fuel, comprising a pump housing (4), a plunger barrel (2) being provided in the pump housing (4), a plunger (1) being provided in the plunger barrel (2) for reciprocating movement along the plunger barrel (2), characterized in that the plunger (1) is a plunger of a plunger pump for supplying fuel according to any one of claims 1 to 6.

8. The plunger pump (3) for supplying fuel as claimed in claim 7, wherein said plunger pump (3) further comprises a lubricating oil chamber (30), said lubricating oil chamber (30) being lubricated with oil.

9. The plunger pump (3) for supplying fuel according to claim 8, wherein a pressure in a lubricating oil chamber (30) of the plunger pump (3) is lower than a pressure above the plunger (1), and the upper intersection point a is located farther from the lubricating oil chamber (30) than the lower intersection point B.