JP2002005037A - Seal device for high-pressure plunger pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal device for a high-pressure pump chamber of a high-pressure plunger pump, which make sure the seal of a high-pressure pump chamber of a high-pressure plunger pump with the pressure of 150 MPa and above, and not necessary to form drain route connected to the suction to avoid the leaking of liquid outside. SOLUTION: This seal device is so constituted that an outlet flat surface 53 of an end edge 52 of cylinder bore 51 forming a pump chamber 6, is formed in a taper shape, and a seal surface 21 of plug 30 for sealing a pump chamber 6 in a taper seal surface 21 with taper angle β, which is different from taper angle α of edge 52 outlet surface 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device for a high-pressure plunger pump that reliably seals a high-pressure pump chamber of a high-pressure plunger pump having a pump chamber in which a reciprocating pump plunger pressurizes by a reciprocating drive device.

[0002]

2. Description of the Related Art A conventional sealing technique for a pump chamber of a high-pressure plunger pump is disclosed in Japanese Patent Application Laid-Open No. 9-11271, in which an annular groove is provided inside an end of a cylinder hole forming a pump chamber. An annular ring having the same diameter as the cylinder hole and having an axial length longer than the annular groove is fitted, the annular ring is pressed against the bottom surface of the suction check valve housing that closes the pump chamber, the suction check valve housing is operated, and the suction check valve is operated. The bottom of the housing of the suction check valve was pushed by the screw of the housing of the closing solenoid valve, and the annular ring was tightened to seal. As a seal for the high-pressure pump chamber of the high-pressure plunger pump, the outlet plane of the end edge of the cylinder hole forming the high-pressure pump chamber is formed in a horizontal plane, as disclosed in WO 99/02858, and FIG. A small-diameter annular projection edge is provided on the bottom surface of the plug that seals the opposing high-pressure pump chamber, the plug is fastened with a screw, and the small-diameter annular projection edge on the bottom surface of the plug is tightened by increasing the surface pressure to a horizontal plane to perform sealing.

[0003]

However, in the structure disclosed in Japanese Patent Application Laid-Open No. 9-11271, processing accuracy such as surface roughness and parallelism of the sheet surface is important in order to eliminate leakage from the pump chamber. When the pressure was 150 MPa or more, the sealing property was extremely poor, and it was extremely difficult to completely seal. Further, as disclosed in FIG. 3 of WO 99/02858, a method of sealing by contacting a small-diameter annular projection edge provided on the plug bottom surface with an outlet horizontal surface of a cylinder hole end edge forming a pump chamber is disclosed. When sealing a high pressure of MPa or more, a deformation of several μm in the radial direction of the cylinder hole due to the high pressure in the cylinder hole forming the pump chamber occurs every time the pressure rises due to the reciprocation of the pump plunger, and the deformation received repeatedly causes the annular ring of the plug. The contact portion between the protruding edge and the exit horizontal surface of the end edge of the cylinder hole was worn, the sealing performance was impaired, the leakage of the high-pressure portion increased, and the volume efficiency was reduced. Further, since there is a possibility of leakage, it is necessary to form a drain passage communicating with the suction side so that the leaked liquid does not go outside, and there is no design freedom.

An object of the present invention is to provide a high-pressure plunger pump.
High-pressure plunger pump high-pressure pump chamber seal that can reliably seal the high-pressure pump chamber at 150 MPa or more and does not need to form a drain passage communicating with the suction side so that leaked liquid does not go outside. It is to provide a device.

[0005]

According to the present invention, the pump chamber is formed in a high-pressure plunger pump having a pump chamber formed in a pump housing and pressurized by a pump plunger reciprocating by a reciprocating drive device. The exit plane of the cylinder hole end edge is formed as a tapered surface, and the sealing surface of the plug that seals the pump chamber is
A taper seal surface having a taper angle different from the taper angle of the exit plane of the edge, and the taper seal surface is brought into contact with the taper surface, and either the edge or the taper seal surface end edge, or the The object has been achieved by providing a sealing device for a high-pressure plunger pump, wherein an edge and an end edge of the tapered seal surface are edge-sealed.

According to this structure, in the structure of the prior art, the processing accuracy such as the surface roughness of the sheet surface, the parallelism of the contact surface, and the flatness is important, and the cost is high, and the surface pressure to be suppressed due to the contact between the flat surfaces is low. When the pressure is 150 MPa or more, the sealing performance is extremely poor, and it is extremely difficult to completely seal even if the pressing force is increased.However, according to the present invention, the sealing portion of the high-pressure pump chamber has a different angle. Since the sheet part is in line contact with the edge by receiving it at the tapered part, processing accuracy such as flatness and surface roughness is not required, and even if the pressing force is small, the tapered seal surface is brought into contact with the tapered seal surface. The edge of the cylinder bore or the edge of the taper seal surface forming the pump chamber, or the edge and the edge of the taper seal surface are edge-sealed. Utilizing the deformation of the metal edge caused by the tightening pressure, the high-pressure plunger pump can reliably seal even at a high pressure of 150 MPa or more and does not need to form a drain passage communicating with the suction side so that leaked liquid does not go outside. The present invention provides a high-pressure pump chamber sealing device.

Preferably, the taper angle α of the taper seal surface of the plug is set to an acute angle smaller than the taper angle β of the outlet taper surface of the end edge of the cylinder hole, and the sealing surface of the plug is tightened by the tightening pressure of the plug. The amount of deformation may be greater than the amount of deformation of the cylinder hole end edge due to the pressure in the cylinder chamber. Further, a small-diameter hole having a diameter of 0.5 to 0.7 times the inner diameter of the pump chamber is provided on the bottom surface of the plug, and the small-diameter hole of the plug is deformed outward by the fluid pressure of the fuel oil in the pump chamber. Of the present invention. Further, the outlet plane of the end of the cylinder hole forming the pump chamber is formed as a tapered surface, and a shallow medium-diameter hole having substantially the same diameter as the diameter of the pump chamber is provided on the bottom surface of a plug for sealing the pump chamber. The medium pressure hole of the plug is deformed outward by the fluid pressure of the fuel oil pressurized to a high pressure in the chamber, and an annular concave tapered surface is formed between the outer periphery of the bottom surface of the plug and the outer periphery of the medium diameter hole. Further, between the cylinder hole end edge and the plug, a tapered lens seal surface having a different taper angle from the annular concave taper surface on the bottom surface of the plug and the outlet taper surface on the cylinder hole end edge, respectively, are provided. A lens seal may be inserted, and the annular concave tapered surface and the tapered lens seal surface, and the outlet tapered surface and the tapered lens seal surface may be brought into contact with each other to utilize deformation of two metal edges.

[0008]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall schematic sectional view of a high-pressure plunger pump in which a sealing device for a high-pressure plunger pump according to an embodiment of the present invention is used. FIGS. 2 to 6 show a plug 20 and a high-pressure pump chamber of the high-pressure plunger pump in FIG.
FIG. 6 is a partially enlarged cross-sectional view of a sealing device of a high-pressure plunger pump, showing six different parts, showing different first to fifth embodiments of the present invention. A high-pressure plunger pump shown in FIG. 1 in which a sealing device for a high-pressure plunger pump according to an embodiment of the present invention is used, is formed in a pump housing 1 and is urged by a spring 2 and rotated by an input shaft 3. Pump plunger 5 reciprocating via cam 4 (pump plunger 5 may be reciprocated by another reciprocating device such as a solenoid valve), pump chamber 6 in which pump plunger 5 pressurizes, and pump chamber 6 A pump is actuated by a suction check valve 9 arranged at the suction port 7 and connected to the feed fuel passage 8 and a discharge check valve 11 connected to the discharge port 10 of the pump chamber.
Reference numerals 31 and 32 denote sliding bearings interposed by the input shaft 3 supporting the cam 4 at both ends, and reference numeral 33 denotes a sliding bearing interposed between the cam 4 and the cam outer ring 35. The pump plunger 5 is arranged so as to face the cam 4, but may be arranged at an angle of 120 ° radially at equal intervals in the circumferential direction.

In operation, an input shaft 3 is rotated by an engine (not shown), and a fuel oil supply pump 12 incorporated in a rear portion of the inside of the pump housing 1 and rotated by the input shaft 3 is connected to a fuel oil suction port from a tank 13.
Inhale the fuel oil through 15. The fuel oil discharged from the supply pump 12 is connected to the suction port 7 side of the high-pressure plunger pump through a feed fuel passage 8. The cam driven by the external power is rotated, and the pump plunger 5 in contact with the cam 4 is driven reciprocally. A suction check valve element 92 is disposed in the pump housing 1 at the suction port 7 of the pump chamber 6 and communicates with the feed fuel passage 8, and the suction check valve element 92 is pressed against a valve seat by a suction check valve spring 91. . Pump plunger 5 is cam 4
When the pressure difference between the negative pressure in the pump chamber 6 and the set pressure of the relief 14 in the feed fuel passage 8 becomes larger than the force of the suction check valve spring 91, the suction check valve
Reference numeral 92 opens to allow the fuel oil sent from the fuel oil supply pump 12 to enter the pump chamber 6. When the pump plunger 5 moves up along the cam 4, the fuel oil pressurized to a high pressure of 150 MPa or more in the pump chamber 6 closes the suction check valve 92, opens the discharge check valve 11, and pressurizes the fuel oil from the discharge port 16. Is discharged to a common rail device (not shown).

In the sealing device for a high-pressure plunger pump according to the first embodiment of the present invention shown in FIG. 2, an outlet flat surface 53 of an end edge 52 of a cylinder bore 51 forming a pump chamber 6 is formed on a tapered surface 53. The sealing surface 21 of the plug 20 for sealing the pump chamber 6 is a taper sealing surface 21 having a taper angle β different from the taper angle α of the outlet plane 53 of the edge 52. In the present invention, the seal of the pump chamber 6 is attached to the end of the end of the cylinder hole 51.
Seal surface 21 of plug 20 for sealing with outlet taper surface 53 of 52
The taper seal surface 21 is brought into contact with the taper surface 53 so that the edge seal E is formed at the end edge 52 of the cylinder hole 51. It is not necessary to form a drain passage for reliably sealing even at a high pressure of 150 MPa or more and communicating with the suction side so that leaked liquid does not go outside. In the sealing device for the high-pressure plunger pump shown in FIG.
The taper angle α of the seal surface 21 of the plug 20 is set to an acute angle smaller than the taper angle β of the outlet taper surface 53 of the end edge 52 of the cylinder hole 51, and the sealing surface of the plug 20 due to the tightening pressure of the plug 20
The amount of deformation 21 is larger than the amount of deformation of the cylinder hole end edge 52 due to the pressure in the cylinder chamber 6. Further, a small-diameter hole 23 which is 0.5 to 0.7 times the inner diameter of the pump chamber 6 is provided on the bottom of the plug 20.
The plug small-diameter hole 23 is deformed outward by the fluid pressure f of the fuel oil pressurized to a high pressure in the pump chamber 6, thereby providing a higher-pressure pump chamber sealing device.

In a sealing device for a high-pressure plunger pump according to a second embodiment of the present invention shown in FIG. 3, a taper seal surface 21 is brought into contact with an outlet taper surface 53 of an end edge 52 of a cylinder hole 51 so that a cylinder hole is formed. 2 except that an end seal 52 is formed between the end edge 52 and the end edge 22 of the taper seal surface.
This is the same as the sealing device of the high-pressure plunger pump according to the first embodiment shown in FIG. 4, and has the same effect as that shown in FIG. In the sealing device according to the second embodiment shown in FIG. 3, the tapered seal surface end edge 22 is made smaller in diameter, and the tapered seal surface end edge 22 abuts on the outlet tapered surface 53 of the cylinder bore 51 end edge 52. Even if the taper seal surface end edge 22 is edge-sealed, the same effect as that of the sealing device shown in FIG. 3 can be obtained.

In a sealing device for a high-pressure plunger pump according to a third embodiment of the present invention shown in FIG. 4, an outlet flat surface 53 of an end edge 52 of a cylinder bore 51 forming a pump chamber 6 is formed on a tapered surface 53. A shallow medium-diameter hole 44 having substantially the same diameter as the inner diameter of the pump chamber 6 is provided on the bottom surface of the plug 40 that seals the pump chamber 6, and the plug medium-diameter hole 44 is formed by the fluid pressure f of the fuel oil pressurized to a high pressure in the pump chamber 6. Is deformed outward, and plug 40
An annular concave taper surface 47 is formed between the outer periphery of the bottom surface of the plug 40 and the outer periphery of the medium diameter hole 44. Further, between the end edge 52 of the cylinder hole 51 and the plug 50, the annular concave taper surface 47 of the bottom surface of the opposing plug 40 is formed. And the exit plane 53 of the cylinder hole 51 end edge 52 is tapered surface 53
And a lens seal 55 having a taper lens seal surface 48, 49 having a different taper angle, and an annular concave taper surface 47, a taper lens seal surface 49, and an outlet taper surface.
53 and the tapered lens sealing surface 48 are brought into contact with each other, and between the outer peripheral edge of the tapered lens sealing surface 49 and the annular concave tapered surface 47, and between the outer peripheral edge of the tapered lens sealing surface 58 and the exit edge 52 of the cylinder hole 51 end edge 52. 53 and taper lens seal surface 58
A higher pressure seal can be achieved by utilizing the deformation of the two metal edges between the inner peripheral edges.

In a sealing device for a high-pressure plunger pump according to a fourth embodiment of the present invention shown in FIG. 5, a lens seal 55 inserted between an end edge 52 of a cylinder bore 51 and a plug 50 is provided.
Between the outer peripheral edge of the tapered lens sealing surface 59 and the annular concave tapered surface 57, and between the outer peripheral edge of the tapered lens sealing surface 58, the exit tapered surface 53 of the cylinder hole 51 end edge 52, and the inner peripheral edge of the tapered lens sealing surface 58. Except for utilizing the deformation of the two metal edges, the sealing device according to the third embodiment of the present invention shown in FIG. 4 has the same effect as that shown in FIG.

In a sealing device for a high-pressure plunger pump according to a fifth embodiment of the present invention shown in FIG. 6, a lens seal 65 inserted between an end edge 52 of a cylinder bore 51 and a plug 60 is provided.
Is made longer in the axial direction than the lens seals 45 and 55 in FIGS. 4 and 5, the taper angle of the taper lens seal surfaces 68 and 69 is made a small acute angle, and the pressing force (sealing force) by pressure is obtained.
And two metal edges between the inner peripheral edge of the tapered lens seal surface 69 and the outer peripheral edge of the middle diameter hole 64 on the bottom of the plug 60, and between the inner peripheral edge of the tapered lens seal surface 68. Is the same as the sealing device of the third embodiment of the present invention shown in FIG.
It provides a stronger sealing effect than the sealing device shown in FIGS.

[0015]

As described above, according to the present invention, it is possible to greatly improve the processing accuracy of the high pressure seal of the pump chamber of the high pressure plunger pump of 150 MPa or more, which is extremely difficult, such as the surface roughness and parallelism of the seat surface. It can be performed without any trouble, and due to the repeated deformation of the cylinder hole, such as when the small diameter annular projection edge provided on the plug bottom surface is brought into contact with the outlet horizontal surface of the cylinder hole end edge and sealed, the annular projection edge of the plug is There is no need to form a drain passage communicating with the suction side so that the leaked liquid does not come out to the outside because there is no high pressure leakage because the contact part of the suction check valve is not worn and the sealability is not impaired. High-pressure plan that can be freely designed in position and can respond to dimensional restrictions (reducing the height or changing the position of the suction check valve) when mounted on a vehicle It was intended to provide a seal device of the high-pressure pump chamber Yaponpu. Preferably, a small-diameter hole having a diameter of 0.5 to 0.7 times the inner diameter of the pump chamber is provided on the bottom surface of the plug,
The sealing structure of the tapered surface and the fluid pressure in the pump chamber deform the plug small-diameter hole outward, so that even if the pressure in the pump chamber increases, the sealing force is increased without reducing the sealing force. By adopting a self-sealing structure that does not cause relative sliding of the parts, the finishing accuracy is simple, and even at a high pressure of 150 MPa or more, sealing is ensured, and the reduction of volumetric efficiency and external leakage can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic elevation sectional view of a high-pressure plunger pump in which a sealing device for a high-pressure plunger pump according to an embodiment of the present invention is used.

FIG. 2 is an enlarged schematic sectional view showing a sealing device of the high-pressure plunger pump according to the first embodiment of the present invention.

FIG. 3 is an enlarged schematic sectional view showing a sealing device for a high-pressure plunger pump according to a second embodiment of the present invention.

FIG. 4 is an enlarged schematic sectional view showing a sealing device for a high-pressure plunger pump according to a third embodiment of the present invention.

FIG. 5 is an enlarged schematic sectional view showing a sealing device for a high-pressure plunger pump according to a fourth embodiment of the present invention.

FIG. 6 is an enlarged schematic sectional view showing a sealing device for a high-pressure plunger pump according to a fifth embodiment of the present invention.

[Explanation of symbols]

1 Pump housing 5 Pump plunger 6 Pump chamber 20, 30, 40, 50, 60
... Plug 21 ... Taper seal surface of plug 30 22 ... Taper seal surface end edge 23 ... Small diameter hole 44 ... Medium diameter hole 45,55,65 ... Lens seal 47,57・ ・ ・ Circular concave tapered surface 48, 49, 58, 59, 68, 69 ・ ・ ・ Tapered lens seal surface 51 ・ ・ ・ Cylinder hole 52 ・ ・ ・ Cylinder hole end edge 53 ・ ・ ・ Cylinder hole end edge outlet Plane

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yama ▲ saki ▼ 1-1-1, Fujikoshi-Honcho, Toyama-shi, Toyama Pref. No. 1 Stock Company Fujikoshinai F-term (reference) 3H070 AA01 BB02 BB07 BB17 BB23 BB25 CC29 DD01 3H071 AA03 BB01 CC28 DD06 DD51 3H075 AA02 BB03 BB20 CC16 DA03 DB23

Claims (5)

[Claims] 1. A high-pressure plunger pump having a pump chamber formed in a pump housing and pressurized by a reciprocating pump plunger by a reciprocating drive device, wherein an outlet plane of an end edge of a cylinder hole forming the pump chamber is formed. A sealing surface of a plug formed on a tapered surface and sealing the pump chamber is a tapered sealing surface having a taper angle different from a taper angle of an exit plane of the edge, and the tapered sealing surface is brought into contact with the tapered surface. A sealing device for a high-pressure plunger pump, wherein either the edge or the tapered sealing surface end edge, or the edge and the tapered sealing surface end edge are edge-sealed. 2. The taper seal surface of the plug has a taper angle α smaller than the taper angle β of the outlet taper surface of the end edge of the cylinder hole, and the plug seal surface is deformed by the tightening pressure of the plug. 2. The sealing device for a high-pressure plunger pump according to claim 1, wherein the amount is larger than an amount of deformation of said cylinder hole end edge due to a pressure in said cylinder chamber. 3. The pump chamber inner diameter is provided on the bottom surface of the plug.
3. A high-pressure plunger pump according to claim 1, wherein a small-diameter hole having a diameter of 0.5 to 0.7 times is provided, and the plug small-diameter hole is deformed outward by a fluid pressure of fuel oil in the pump chamber. Sealing device. 4. An outlet plane of an end edge of a cylinder hole forming the pump chamber is formed into a tapered surface, and a shallow medium-diameter hole having a diameter substantially equal to a diameter of the pump chamber is provided on a bottom surface of a plug for sealing the pump chamber. The middle diameter hole of the plug is deformed outward by the fluid pressure of the fuel oil pressurized to a high pressure in the pump chamber, and an annular concave tapered surface is formed between the outer periphery of the bottom surface of the plug and the outer periphery of the middle diameter hole. A lens seal having a different taper angle between the cylindrical hole end edge and the plug, and an annular concave taper surface on the bottom surface of the plug and an outlet taper surface of the cylinder hole end edge facing each other. The lens seal having a tapered surface is inserted, and the annular concave tapered surface and the tapered lens seal surface and the outlet tapered surface and the tapered lens seal surface are brought into contact with each other. Sealing device of the high-pressure plunger pump according to any one of. 5. The pump plunger is reciprocated by a cam mechanism formed in the pump housing, each of which is biased by a spring and is driven to rotate by an input shaft. Is located opposite the mechanism or 1
The sealing device for a high-pressure plunger pump according to any one of claims 1 to 4, wherein the sealing device is arranged radially at equal intervals in the circumferential direction at an angle of 20 °.