CN1573110A

CN1573110A - Fuel supply apparatus

Info

Publication number: CN1573110A
Application number: CNA200410046300XA
Authority: CN
Inventors: 铃木雅词
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2003-06-04
Filing date: 2004-06-03
Publication date: 2005-02-02
Anticipated expiration: 2024-06-03
Also published as: US20040247464A1; JP2005016514A; EP1484504A1; EP1484504B1; CN100374723C

Abstract

A fuel supply pump comprising a rotary feed pump according to the present invention improves its pump performance by making smaller side clearances in an axial direction at both sides of a pump element PE. Multiple through-holes (22a and 23a) passing through in an axial direction are respectively formed at top portions of cogs of the outer rotor (22) and the inner rotor (23), which form a pump element (PE) of a feed pump (3). Accordingly, pressures in the thrust direction at both axial sides of the rotors (22 and 23) can be equalized, since the side clearance formed at both axial sides of the rotors (22 and 23) are communicated with each other. As a result, since the rotors (22 and 23) can be floated, without contacting with the pump cover (19) and the pump plate (20), the abnormal wear and seizures can be suppressed, even when side clearance between the pump cover (19) and the pump element (PE) is made smaller.

Description

Fuel facility

Technical field

The present invention relates to the fuel facility of internal-combustion engine, more particularly, relate to the rotary pump that is used for fuel injection system, wherein said ejecting system is used for supply of fuel to diesel engine.

Background technique

For example shown in the US2003/0044288 A1 U.S. Patent Application Publication file like that, as one of fuel injection system of prior art, what we had known is, fuel-injection pump has to be extracted fuel and the feed pump of fuel supply to the main pump of fuel-injection pump out from fuel tank.

As shown in Figure 6, feed pump comprises pump element 110 that the camshaft 100 by main pump drives, forms rotor chamber also pump element 110 be contained in wherein pump cover 120 and with the pump plate 130 of pump cover 120 with fluid tight manner enclosed rotor chamber opening side, wherein pump cover 120 is screwed on the side surface of pump case 140.

In addition, as shown in Figure 7, pump element 110 is a trochoidal curve type pump, comprise external rotor 111 and be positioned at external rotor and have the internal rotor 112 of external tooth with internal tooth, wherein many one of external rotor 111 gear ratio internal rotors 112, the rotating center Oi of the rotating center Oa of external rotor and internal rotor is eccentric simultaneously is provided with.As a result, when internal rotor 112 by camshaft 100 and during rotary driving, external rotor 111 is also with internal rotor 112 rotations, thereby will be gradually changed by the working chamber volume that adjacent teeth forms, fuel is extracted out from fuel tank also described fuel is extracted into main pump.

In the feed pump of Miao Shuing, as shown in Figure 6, the side clearance between pump cover 120 and pump element 110 is very little in the above, so that fuel losses amount minimum, and increase fuel feed efficient.Yet, if side clearance is too little, because the deviation of parts can not be absorbed in manufacture process, therefore heel and toe wear, jam etc. might appear.

Summary of the invention

The present invention is directed to the problems referred to above and design, the purpose of this invention is to provide a kind of fuel facility simultaneously with rotary pump, wherein the very little pump performance that makes improves in the axial side gap of pump element both sides by making, and can not produce Metal Contact simultaneously between pump element and corresponding parts.

According to a feature of the present invention, a kind of fuel facility comprises: have the rotary pump of rotor and pump chamber, the volume of described pump chamber changes along with the rotation of rotor, is used for pressurizeing and discharging the fuel of this pressurization being drawn into fuel in the pump chamber.Described rotary pump is characterised in that a plurality of through holes axially are formed in the rotor at it, and the side clearance that is formed on the rotor both sides communicates with each other by these through holes.

According to said structure, communicate with each other owing to the side clearance that is formed on the rotor both sides is formed on epitrochanterian a plurality of through hole by those, thereby the pressure of rotor both sides (promotion pressure) obtains equilibrium in the axial direction.As a result, can obtain even side clearance in the rotor both sides.In other words, rotor is floated.Therefore, by make side clearance that the rotor both sides form its axially form the very little fuel feed efficient that improved, owing to be inhibited at rotor that forms side clearance and the Metal Contact between the miscellaneous part, problems such as heel and toe wear, jam also are inhibited simultaneously.

According to other feature of the present invention, described a plurality of through holes form with equidistance on the circumferencial direction of rotor.

According to this spline structure, because the pressure (promotion pressure) in the rotor both sides obtains equilibrium by those a plurality of through holes, wherein a plurality of through holes are positioned on those aspects of equidistance of rotor circumference direction, thereby can obtain uniform side clearance on nearly all rotor circumference point.Therefore, by making the very little fuel feed efficient that improves of side clearance, owing to the Metal Contact between rotor and the miscellaneous part is inhibited, so problems such as heel and toe wear, jam also are inhibited.

According to another feature of invention, rotary pump is a trochoidal curve type pump, comprises external rotor with internal tooth and is positioned at external rotor and has the internal rotor of external tooth, and wherein through hole is formed on the top or the bottom of tooth.

Owing to form through hole on the internal rotor by camshaft actuated, internal rotor gets up with regard to floatability.As a result, in the internal rotor rotary course, suppressed the Metal Contact between internal rotor and the miscellaneous part, thereby can suppress the appearance of problems such as heel and toe wear, jam.

According to another feature of the present invention, rotary pump has through hole in each top or the bottom of tooth.

In this case, in the top or the bottom of each internal rotor tooth, the pressure on pushing direction obtains equilibrium, and internal rotor can be floating more reliably, to suppress the Metal Contact between internal rotor and the miscellaneous part.

According to another feature of the present invention, the external rotor of rotary pump has a plurality of through holes, these through holes at the top of tooth or the bottom axially to pass, wherein a plurality of through holes are arranged with equidistance at the circumferencial direction of external rotor.

Owing to, on external rotor, also formed through hole, so the promotion pressure of external rotor obtains equilibrium equally except the through hole of internal rotor.As a result, external rotor can be positively floating with internal rotor.

According to other feature of the present invention, rotary pump is as the feed pump of the fuel-injection pump of diesel engine, and wherein said feed pump comprises: the pump element (PE) that round rotor chamber, pump cover and pump plate, described pump cover are used for inner and outer rotors covers in the rotor chamber; Described pump plate is used for the opening end of pump cover with fluid tight manner enclosed rotor chamber.The pump strip has the fuel port that is communicated with rotor chamber, and pump cover is screwed into the side of the housing of fuel-injection pump, thereby the pump plate presses against on the described side.

According to said structure, the side clearance between the side clearance between pump element and the pump cover and pump element and pump plate can be designed to littler, improving fuel feed efficient, thereby and improves pump performance as feed pump.

According to other feature of the present invention, rotary pump is the leaf type pump, and described leaf type pump comprises the rotor that has blade groove and is inserted into the interior blade of blade groove movably.

In described leaf type pump, because the rotor with blade is driven by camshaft and rotates, therefore, utilize and be formed on epitrochanterian a plurality of through hole, by making the promotion isostasy, the rotor floatability is got up.As a result, the Metal Contact between rotor and miscellaneous part can be inhibited.

Description of drawings

From detailed description with reference to the accompanying drawings, above-mentioned and other purposes, feature and advantage of the present invention will become more obvious.

Fig. 1 is the sectional drawing of the feed pump of first embodiment of the invention;

Fig. 2 is the front elevation of the pump element of feed pump shown in Figure 1;

Fig. 3 is the sectional drawing that has the fuel-injection pump of feed pump of the present invention;

Fig. 4 is the front elevation of the pump element of second embodiment of the invention;

Fig. 5 is the front elevation of third embodiment of the invention pump rotor;

Fig. 6 is the sectional drawing of prior art feed pump;

Fig. 7 is the pump element front elevation of feed pump shown in Figure 6.

Embodiment

(first embodiment)

Explain the present invention below with reference to embodiment.

In first embodiment, such embodiment is described, fuel facility wherein of the present invention is used in the fuel-injection pump of public oil pipe (common rail) fuel injection system of diesel engine.

Fig. 1 is the sectional drawing of feed pump, and Fig. 2 is that front elevation and Fig. 3 of pump element is the sectional drawing of fuel-injection pump.

As shown in Figure 3, fuel-injection pump 1 has main pump 2 and feed pump 3, and wherein main pump 2 is used for fuel is pressurizeed and extracts fuel out, and feed pump 3 (see figure 1)s be used for from the fuel tank (not shown) fuel is extracted out and described fuel feed to main pump 2.

Main pump 2 comprise by the diesel engine (not shown) drive and the camshaft 4 of rotation, rotatably supporting cam wheel axle 4 pump case 5, drive in cylinder body 6 reciprocating plunger 7 etc. by camshaft 4.

Cam 8 with circular cross section is fixed on the camshaft 4, wherein the rotating center off-centre of its rotating center and camshaft.Cam ring 10 rotatably is supported on the periphery of lining 9 overhead cams 8.Form a pair of plat surface on cam ring 10, wherein said plat surface makes progress toward each other in the footpath of cam 8.

A pair of cylinder head 11 is assembled on the pump case 5 with fluid tight manner, and wherein said cylinder head 11 makes progress toward each other in the footpath of camshaft 4.

Cylinder head 11 has confession plunger 7 and is inserted into cylinder body 6 wherein, the suction ports 12 that is communicated with described cylinder body 6 etc.Safety check 13 is assembled on the cylinder head at the opposite side of cylinder body 6.Tubular union 15 is screwed on the cylinder head at the outlet side of suction ports 12, is used for being connected with fuel pipe 14.

Safety check 13 is between fuel channel (not shown) that is communicated with feed pump and cylinder body 6.In the induction stroke of plunger 7 motion downwards in cylinder body 6 (inwardly motion), safety check 13 will be opened, be incorporated into the inboard of cylinder body 6 from the fuel of feed pump 3 feedings with handle, and in the discharge stroke in plunger 7 upwards motion in cylinder body 6 (outwards motion), safety check 13 will cut out, thereby stop the fuel that is incorporated in the cylinder body 6 to flow back into feed pump 3.

Suction ports 12 has a small diameter ports and a major diameter port.Between minor diameter and major diameter port, has conical valve seating face (see figure 3).Ball valve 17 is positioned at suction ports 12, and pushes described valve base surface to by spring 16, thereby described minor diameter and major diameter port are stopped by described ball valve 17.

When fuel pressure is bigger than the thrust of spring 16, ball valve 17 will rise from described valve base surface, thereby minor diameter and major diameter port are communicated with each other, fuel pressure wherein in induction stroke by plunger 7 pressurizations.

Plunger 7 side within it has plunger head 7a, and described plunger head 7a is promoted by spring 18, and presses the outer surface (plat surface) of cam ring 10.When the rotation of camshaft 4 is delivered to cam ring 10 by cam 8, cam ring 10 moves in the mode of orbiting along its track, the rotating center of its middle orbit and camshaft 4 departs from certain distance, and simultaneously cam ring 10 keeps its orientation (cam ring 10 is rotation on the axle of itself and cam 8 not).As a result, be pressed against plunger 7 to-and-fro motion in cylinder body 6 on the plat surface of cam ring 10.

Feed pump 3 comprises pump element PE, pump cover 19 and pump plate 20, and these will illustrate below.As shown in Figure 3, feed pump 3 is fixed on the side of pump case 5 by bolt 21.

Pump element PE is the trochoidal curve type pump of knowing, and comprises the external rotor 22 with internal tooth and is positioned at external rotor 22 and has the internal rotor 23 of external tooth, and wherein internal rotor connects with camshaft 4 by key, thereby internal rotor rotates by camshaft 4.

External rotor 22 has tooth, many of gear ratio internal rotor 23, and the rotating center Oi off-centre of the rotating center Oa of external rotor 22 and internal rotor 23 is provided with (see figure 2).Therefore, when internal rotor 23 rotated by camshaft 4, external rotor 22 rotated with internal rotor 23, thereby will be changed by the working chamber volume that tooth forms, so that fuel is extracted into main pump 2 from fuel tank.

As shown in Figure 2, through hole 22a, the 23a that axially passes external rotor 22 and internal rotor 23 is respectively formed on external rotor 22 and the internal rotor 23.Have a plurality of through

hole

22a and 23a on external rotor 22 and internal rotor 23, these through holes are gone up at circumferencial direction (or rather, external rotor 22 and internal rotor 23 each tooth top portion) with equidistance and are formed.

As shown in Figure 1, pump cover 19 has round rotor chamber 19a, is used for pump element PE is contained in wherein.The internal diameter of rotor chamber 19a is bigger slightly than the external diameter (being the external diameter of internal rotor 23) of pump element PE, thereby internal rotor 23 can rotate therein.The width of rotor chamber 19a is bigger slightly than the width of pump element PE (at thickness longitudinally), thereby has kept the side clearance of certain distance between pump element PE and pump chamber internal surface.

Pump plate 20 is assembled on the pump cover 19 with fluid tight manner, to close the opening of rotor chamber 19a.Pump plate 20 has the center hole and fuel port 20a (entrance and exit) (see figure 1) around described center hole of passing for camshaft 4.Fuel port 20a is communicated with the active chamber 24 that is formed between external rotor 22 and the internal rotor 23.

Above-mentioned first embodiment's operation is described below.In above-mentioned feed pump 3, a plurality of through

hole

22a and 23a are respectively formed on external rotor 22 and the internal rotor 23, and these a plurality of through

hole

22a and 23a arrange with equidistance at the circumferencial direction of external rotor 22 and internal rotor 23.Owing to communicate with each other by those a plurality of through

hole

22a and 23a at the side clearance that axially is formed on external rotor 22 and internal rotor 23 both sides, then at the pressure of external rotor 22 and internal rotor 23 both sides pushing directions with equilibrium.As a result, can obtain uniform side clearance in the both sides of external rotor 22 and internal rotor 23.

According to said structure, external rotor 22 and internal rotor 23 can float, and do not contact with pump plate 20 with pump cover 19.Specifically, because through hole 23a is formed on each tooth top portion of internal rotor 23, described tooth top portion is corresponding with the excircle of internal rotor, can suppress the inclination of internal rotor 23 effectively, thereby can obtain along the even side clearance of two vertical sides of internal rotor 23 circumference.

Therefore, by avoiding the Metal Contact between pump element PE and pump cover 19 and the pump plate 20, even do the side clearance between pump element PE and the pump cover 19 lessly, also can suppress the appearance of problems such as heel and toe wear and jam, thereby finally improve the performance of feed pump 3 to increase supply of fuel efficient.

In the above among first embodiment, through

hole

22a and 23a are formed on external rotor 22 and internal rotor 23 on both.Yet, when through hole 23a only is formed on the internal rotor 23 that is directly driven by camshaft 4, also can obtain positive effect (suppressing heel and toe wear and jam).

(second embodiment)

Fig. 4 is the front elevation of second embodiment's pump element PE.

In first embodiment, a plurality of through

hole

22a and 23a are formed on equidistance on external rotor 22 and the internal rotor 23 at circumferencial direction.Yet, unnecessary through hole is arranged with equidistance.As shown in Figure 4, through hole 23a can not be formed on the internal rotor 23 with equidistant in a circumferential direction.Though only show the through hole that is used for internal rotor 23 among Fig. 4, through hole 22a can not be formed on the external rotor 22 with equidistant in a circumferential direction with the same way as for internal rotor 23.

(the 3rd embodiment)

Fig. 5 is the front elevation according to the 3rd embodiment's rotor 25.

The 3rd embodiment is applicable to the embodiment of leaf type pump for rotary pump of the present invention.

As shown in Figure 5, the leaf type pump has rotor 25 and blade 26, and rotor 25 is forming a plurality of blade groove 25a with equidistance on its circumferencial direction on its excircle, and blade 26 is inserted in the blade groove 25a respectively movably.

When a plurality of through hole 25b are formed on the rotor 25 and rotor 25 when floating, identical with mode among first embodiment, can avoid the Metal Contact with miscellaneous part, thereby suppress the appearance of problems such as heel and toe wear and jam.

In the embodiment shown in fig. 5, through hole 25b is formed on the both sides of respective vanes 26, and the circumferential distance of the through hole 25b between respective vanes 26 is arranged to be equal to each other simultaneously.Yet the circumferential distance of through hole 25b is unnecessary to be equated, and can be not wait.

(other embodiments)

Above among the illustrated embodiment, fuel facility of the present invention is used in the fuel-injection pump of public oil pipe fuel injection system of diesel engine.But the invention is not restricted to these embodiments, the present invention also can be used in the petrolift of petrol engine.

Claims

1. fuel facility, comprise: rotary pump (3) with rotor (22,23 and 25) and pump chamber (24), the volume of described pump chamber (24) changes along with the rotation of rotor (22,23 and 25), be used for pressurizeing and discharging the fuel of described pressurization to being drawn into fuel in the pump chamber (24), wherein:

A plurality of through holes (22a, 23a and 25b) axially are formed in the rotor (22,23 and 25b) at it, and

The side clearance that is formed on rotor (22,23 and 25) both sides communicates with each other by these through holes (22a, 23a and 25b).

2. according to the fuel facility of claim 1, wherein said a plurality of through holes (22a and 23a) form with equidistance on the circumferencial direction of rotor (22 and 23).

3. according to the fuel facility of claim 1, wherein said rotary pump (3) is a trochoidal curve type pump, comprise external rotor (22) and be positioned at external rotor (22) and have the internal rotor (23) of external tooth that wherein through hole (22a and 23a) is formed on the top or the bottom of tooth with internal tooth.

4. according to the fuel facility of claim 3, wherein rotary pump (3) has through hole (22a and 23a) in each top or the bottom of tooth.

5. according to the fuel facility of claim 3, wherein the external rotor (22) of rotary pump (3) has a plurality of through holes (22a), these through holes at the top of tooth or the bottom axially to pass.

6. according to the fuel facility of claim 3, wherein fuel facility is the fuel-injection pump (1) of diesel engine, and wherein rotary pump (3) is as feed pump, and wherein said feed pump (3) comprising:

Round rotor chamber (19a);

Pump cover (19), described pump cover are used for the pump element (PE) of inner and outer rotors (22 and 23) is covered in the rotor chamber (19a); And

Pump plate (20) is used for the opening end of pump cover (19) with fluid tight manner enclosed rotor chamber (19);

Wherein pump plate (20) has the fuel port (20a) that is communicated with rotor chamber (19a), and pump cover (19) is screwed into the side of the housing (5) of fuel-injection pump (1), thereby pump plate (20) presses against on the described side.

7. according to the fuel facility of claim 1, wherein rotary pump is the leaf type pump, and described leaf type pump comprises the rotor (25) that has blade groove (25a) and is inserted into the interior blade (26) of described blade groove (25a) movably.

8. fuel facility that is used for internal-combustion engine comprises:

Be used for the main pump (1) and be fixed to of high-pressure fuel supply to the motor is used on the described main pump (1) from fuel tank the feed pump (3) of fuel feed to main pump (1), wherein said feed pump comprises:

Form the pump case (19 and 20) of pump chamber (19a) and operationally connect the pump rotor (22,23 and 25) that also rotatably is supported in the pump chamber (19a) with main pump (1);

Wherein a plurality of through holes (22a, 23a and 25b) are formed on the rotor (22,23 and 25), thereby the side clearance between two sides of pump case (19 and 20) and rotor (22,23 and 25) communicates with each other.

9. fuel facility according to Claim 8, wherein said a plurality of through holes are formed on the rotor with equidistance at circumferencial direction.

10. fuel facility according to Claim 8, wherein feed pump (3) is a trochoidal curve type pump, described pump comprises:

The rotatable external rotor (22) that is supported in the pump case (19 and 20) and has internal tooth; And

Be positioned at external rotor (22) and have the internal rotor (23) of external tooth;

Wherein said a plurality of through hole (22a and 23a) is formed on the corresponding tooth.