CN1776215A

CN1776215A - High pressure fuel pump

Info

Publication number: CN1776215A
Application number: CN 200510125377
Authority: CN
Inventors: 井上宏史
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2004-11-16
Filing date: 2005-11-16
Publication date: 2006-05-24

Abstract

An oil seal (70) is engaged with a small diameter portion (43) of a plunger (40). Thus, even when a diameter of a large diameter portion (42) of the plunger (40) and a diameter of the cylinder (36) are increased, a modification of a design of the oil seal (70), which is engaged with the small diameter portion (43), is not required.

Description

High pressure fuel pump

Technical field

The present invention relates to a kind of high pressure fuel pump.

Background technique

Have high pressure fuel pump in the prior art, it utilizes a plunger to the fuel in pressurized chamber pressurization (can referring to corresponding to the 2001-295730 Japanese laid-open patent of 2003/0103853A1 U.S. Patent application and corresponding to the flat 8-68370 Japanese laid-open patent of No. 5567134 U. S. Patent).In these high pressure fuel pumps, fuel can leak into drive unit one side of drive plunger from housing one side that forms the pressurized chamber, and lubricant oil can leak into housing one side from drive unit one side.Owing to this reason, the high pressure fuel pump that above-mentioned two patent documentations-2001-295730 Japanese laid-open patent peace 8-68370 Japanese laid-open patent is mentioned all has seal arrangement, and this device engages with the outer circumferential face of plunger.In such a manner, engaging to the inner peripheral surface fluid-tight of the outer circumferential face of plunger and seal arrangement, to reduce the leakage of fuel and lubricant oil.In addition, disclose a kind of high pressure fuel pump in the flat 11-6475 Japanese laid-open patent, it comprises a seal arrangement, and this device engages with the inner peripheral surface of housing, and the inner peripheral surface of housing is engaging slidably with the outer circumferential face of plunger.In this manner, the inner peripheral surface of housing engages hermetically with the sealing device, to reduce the leakage of fuel and lubricant oil.

But, in the last few years, the flow requirements that goes out to flow of high pressure fuel pump was being improved constantly.Therefore, the plunger size and the size of cylinder of admitting plunger are all in continuous increase.Thereby, for disclosed technology in the above-mentioned unexamined patent document, need design again seal arrangement, with increase corresponding to plunger diameter and cylinder diameter.Thereby the product number of seal arrangement and the product number of shaping die all can increase unfriendly, and disadvantageously: need more step to estimate the performance of this new design seal arrangement.

In addition, seal arrangement engages with the outer circumferential face of plunger or the inner peripheral surface of cylinder.Like this, if plunger diameter or cylinder diameter enlarge markedly, then the total length of seal arrangement contact area will increase.Thereby fuel and lubricant oil can easily let out from this contact area.Can consider to increase the engaging force between seal arrangement and plunger or the housing (it forms described cylinder).But if engaging force increases, then the engagement relationship between seal arrangement and plunger or the housing will cause seal arrangement wearing and tearing to occur.The result is exactly that the serviceability of seal arrangement and reliability have been reduced unfriendly.

In addition, if the diameter of plunger increases, then the weight of plunger also can correspondingly increase.This will cause plunger inertia when carrying out to-and-fro motion to increase.Thereby plunger is followed the ability that drive unit moves and will be reduced unfriendly.Follow the ability of drive unit motion in order to improve plunger, need to increase the weight of actuation gear, wherein, this actuation gear is urged plunger to push up on the drive unit.The result is exactly that the driving force that is used for drive plunger will increase unfriendly, thereby make size that significant increase be arranged.

Summary of the invention

Thereby, an object of the present invention is to provide a kind of high pressure fuel pump, it can alleviate or eliminate such demand-promptly and change design with the seal arrangement of plug engages, even also like this under the situation that the diameter or the cylinder diameter of at least one part of plunger changed.Another object of the present invention provides a kind of high pressure fuel pump, and it has higher relatively sealability and higher reliability.A further object of the present invention provides a kind of high pressure fuel pump, and it has limited enlarging markedly of high pressure fuel pump size.

In order to realize these purposes of the present invention, the application provides a kind of high pressure fuel pump, and it comprises housing, plunger, drive unit and seal arrangement.Formed a cylinder in the housing.Cylinder and the fuel in the housing are gone into circulation road and a fuel and are gone out circulation road and be communicated with.Plunger can be supported in the cylinder slidingly back and forth, and it comprises axial end, large-diameter portion branch and path part.The axial end of plunger matches with housing and defines the pressurized chamber, and plunger pressurizes to the fuel in the pressurized chamber.The large-diameter portion branch has an outer circumferential face, and it engages slidably with the inner peripheral surface of housing, and wherein, the inner peripheral surface of housing forms described cylinder.An opposite axial end is connected on the external diameter that the external diameter of path part divides less than large-diameter portion, path part and plunger, and this axial end present position is opposite with the large-diameter portion branch with the pressurized chamber.Drive unit is used for reciprocally drive plunger.Drive unit is set at the opposite shaft orientation end place of plunger, and this opposite shaft orientation end is opposite with the pressurized chamber.Seal arrangement has slidingsurface, and its outer circumferential face with the path part engages hermetically.

Description of drawings

Can be expressly understood the present invention and other purpose, feature and advantage the most from following description, accompanying Claim and accompanying drawing.In the accompanying drawings:

Fig. 1 is the sectional drawing according to the high pressure fuel pump of first embodiment of the invention;

Fig. 2 is the sectional drawing of the high pressure fuel pump of first embodiment of the invention, and under shown position, plunger is in upper dead center position;

Sectional view among Fig. 3 has been represented the high pressure fuel pump according to second embodiment of the invention;

Sectional view among Fig. 4 has been represented the high pressure fuel pump according to third embodiment of the invention;

Sectional view among Fig. 5 has been represented the high pressure fuel pump according to four embodiment of the invention;

Sectional view among Fig. 6 has been represented the high pressure fuel pump according to fifth embodiment of the invention;

Sectional view among Fig. 7 has been represented the high pressure fuel pump according to sixth embodiment of the invention;

Sectional view among Fig. 8 has been represented the high pressure fuel pump according to seventh embodiment of the invention;

Sectional view among Fig. 9 has been represented the high pressure fuel pump according to eighth embodiment of the invention; And

Figure 10 is the sectional view according to the high pressure fuel pump of ninth embodiment of the invention.

Embodiment

Each mode of execution of the present invention is described below with reference to accompanying drawings.

(first mode of execution)

Fig. 1 has represented the high pressure fuel pump according to first embodiment of the invention.High pressure fuel pump 10 shown in Figure 1 is used as the fuel pump of petrol engine.10 pairs of fuel that come from the fuel tank suction of high pressure fuel pump are carried out pressurization, and the fuel after will pressurizeing goes out to flow to give the sparger (not shown).High pressure fuel pump 10 is controlled the flow that of fuel under high pressure by the switching of control electromagnetic valve 11.High pressure fuel pump 10 comprises solenoid valve 11 and pump mechanism 30.The fuel pressurization that 30 pairs of suctions of pump mechanism come, and the fuel after the discharge pressurization.High pressure fuel pump 10 is not limited to the petrolift as petrol engine, and as alternative, it also can be used as the feed pump, to the diesel engine feed fuel of the internal-combustion engine of other type-for example.

Solenoid valve 11 comprises coil mechanism 12 and valve system 20.Coil mechanism 12 is assembled by the static core body 21 round valve system 20.Coil mechanism 12 is electromagnetic drive mechanisms, and it provides driving force to valve system 20.Connector 13 is resin forming spares, and its screening is being wrapped a drum 14 and is being wrapped in coil 15 on the drum 14.One terminal 16 are connected with coil 15 holding circuits.A cover plate 17 made from metallic material is connected between a static core body 21 and the cover member 26.

Valve system 20 comprises static core body 21, movable core body 22, valve member 23, valve spring 24, valve body 25, sleeve pipe 253 and retainer 254.But be received within the cover member 26 to movable core body 22 to-and-fro motion.Valve member 23 is with movable core body 22 to-and-fro motion.On the downward direction in Fig. 1, valve spring 24 applies the effect of short top to movable core body 22.Valve body 25 has a valve seat 27, and valve member 23 can fit on this valve seat hermetically.

Valve spring 24 is urged to head on movable core body 22, makes it away from static core body 21.Static core body 21 and movable core body 22 have constituted a magnetic circuit.When to coil 15 power supplies, static core body 21 will produce a magnetic attracting force.Thereby movable core body 22 is attracted and has been overcome the short top power of valve spring 24, thus along among Fig. 1 upward to shifting to static core body.Valve body 25, sleeve pipe 253 and retainer 254 are received in housing lid 31 and the housing body 32 fully, and wherein, lid 31 and main body 32 have constituted the pump case of pump mechanism 30.Housing lid 31 and housing body 32 have formed housing of the present invention.Cover member 26 is fixed on the housing lid 31.

Valve body 25 is made into a tubular body, and has formed an intercommunicating pore 252 on this valve body, is communicated with so that tubular inner passage 251 and fuel are gone into circulation road 28.Inner passage 251 and intercommunicating pore 252 will be gone into circulation road 28 by a teasehole 254a on the retainer 254 and be communicated with a pressurized chamber 33.When valve member 23 was landed on the valve seat 27 of valve body 25, inner passage 251 just was closed.Like this, the connection of going between circulation road 28 and the pressurized chamber 33 just is turned off.Low-pressure fuel is gone out to flow to the circulation road 28 from fuel tank by a low pressure pump (not shown).When utilizing 20 pairs of valve systems to go into annexation between circulation road 28 and the pressurized chamber 33 when opening and turn-offing, just can change 33 fuel flow rates that go out to flow to into circulation road 28 from the pressurized chamber.When valve member 23 touched retainer 254, valve member 23 just was restricted to the motion of pressurized chamber's 33 1 sides.

The pump case of pump mechanism 30 comprises housing lid 31 and housing body 32.Housing lid 31 has formed goes into circulation road 28, and be made into housing body 32 be what to be separated.Housing lid 31 is hiding pressurized chamber's 33 1 sides of housing body 31, and couples together by a plurality of bolts 34 and an attachment members 35.Because have the connection power of bolt 34, housing body 32 is sandwiched between housing lid 31 and the attachment members 35.

Housing body 32 has formed a cylinder 36, but plunger 40 to-and-fro motion be supported in this cylinder.Pressurized chamber 33 is surrounded by the end face that is positioned at plunger 40 1 sides on the inner peripheral surface 253a of the inner peripheral surface 32a of housing body 32, sleeve pipe 253, the retainer 254 and the end face 41 of plunger 40.Herein, the inner peripheral surface 32a of housing body 32 has formed cylinder 36.An end that is used as the piston spring 50 of resilient member contacts with spring seat 51, and the other end contacts with another bearing 52.A spring seat 51 and a tappet guide 53 are sandwiched between between housing body 32 and the attachment members 35.Tappet guide 53 is made into to be essentially cylindrical body, and the inner peripheral surface of tappet guide 53 is engaging slidably with the periphery wall of a tappet 54.In this manner, tappet guide 53 is supporting tappet 54 according to the form of axially reciprocating.Tappet 54 has a base portion 541 and a tubular portion 542.On the inner radial position of tappet guide 53, tappet 54 is carried out to-and-fro motion vertically.

Plunger 40 has a large-diameter portion and divides 42, one path part 43, a diameter shrinkage part 44 (or dividing the Any shape concave surface of outer circumferential face indent from minor diameter part) and a head 45.Large-diameter portion divides the external diameter of 42 tools greater than the external diameter of path part 43 and the external diameter of diameter shrinkage part 44.On plunger 40, large-diameter portion divides 42, path part 43, diameter shrinkage part 44 and head 45 are made into one.Large-diameter portion divides on 42 that end face 41 with path part position opposite to surround pressurized chamber 33.Large-diameter portion divides 42 periphery wall (outer circumferential face) 42a to slide along the inner peripheral surface 32a of housing body 32, and this inner peripheral surface has formed cylinder 36.The external diameter of path part 43 divides 42 external diameter less than large-diameter portion, but greater than the external diameter of diameter shrinkage part 44.Path part 43 divides with large-diameter portion that an end opposite is connected on 42, and this end opposite is meant the position opposite with pressurized chamber 33.On plunger 40, the diameter minimum of diameter shrinkage part 44.Diameter shrinkage part 44 is formed between path part 43 and the head 45.An end place opposite with pressurized chamber 33 on plunger 40, head 45 couples together with diameter shrinkage part 44.The external diameter of head 45 equates basically with the external diameter of path part 43.Head 45 contacts with a pedestal 543, and this pedestal is formed in the base portion 541 of tappet 54.Because be provided with diameter shrinkage part 44, so, the position between path part 43 and head 45, plunger 40 caves inward diametrically.

In this embodiment, the external diameter of diameter shrinkage part 44 is set equal to or greater than 3mm.Plunger 40 is bearing the larger axial force that comes from pressurized chamber's 33 mesohigh fuel oils and a drive unit 60.Thereby plunger 40 needs the enough external diameters of maintenance, to reach required intensity.Thereby in this embodiment, the external diameter of the diameter shrinkage part 44 of diameter minimum is set equal to or greater than 3mm on the plunger 40.

Drive unit 60 comprises valve camshaft 61 and pump cam 62 of motor, and the pump cam is disposed on the valve camshaft 61.Pump cam 62 rotates with valve camshaft 61.The outside end face of tappet 54 contacts with pump cam 62, and wherein, this exterior edge face is positioned at the axial outside of base portion 541.In this manner, when pump cam 62 rotates together in company with valve camshaft 61, tappet 54 will be carried out to-and-fro motion in the axial direction according to the cam profile of pump cam 62.

In contrast, the inner side end of tappet 54 contacts with bearing 52, and wherein, interior edge face is positioned at the axial inboard of base portion 541.Piston spring 50 has the active force that expands vertically.In this manner, with the piston spring 50 that spring seat 51 and bearing 52 all contact bearing 52 and tappet 54 are urged the top to pump cam 62.The inner periphery of bearing 52 engages with the diameter shrinkage part 44 of plunger 40.Owing to there is diameter shrinkage part 44, plunger 40 caves inward diametrically.The diameter shrinkage part 44 that radially caves inward on the inner periphery of bearing 52 and the plunger 40 engages.In this manner, to pump cam 62 1 sides, wherein, tappet 54 is engaging with bearing 52 piston spring 50 with tappet 54 short tops.And piston spring 50 utilizes the bearing 52 that engages with diameter shrinkage part 44 with plunger 40 short tops to pump cam 62 1 sides.Adopt above-mentioned structure, plunger 40 and tappet 54 can be carried out to-and-fro motion according to the rule of pump cam 62 cam profiles, thereby move to upper dead center shown in Figure 2 (being also referred to as upper dead center position) from lower dead centre shown in Figure 1 (being also referred to as lower dead point position).

Spring seat 51 is made into a tubular body.Be provided with an oil sealing 70 near on the side of drive unit 60 on the spring seat 51, it is used as seal arrangement.In this manner, oil sealing 70 is set on the opposition side of housing body 32, on the axial direction of plunger 40, and the position opposite of this opposition side and pressurized chamber 33.That is to say that oil sealing 70 is set at the outside of housing body 32.

Oil sealing 70 is made into tubular body, and it is around the peripheral part of plunger 40.Oil sealing 70 comprises hermetic unit 71, supporting part 72 and ring body 73.Interior all slip surface 71a of hermetic unit 71 are engaging the outer circumferential face 43a of plunger 40 path parts 43 slidably.An axial end of supporting part 72 is supporting hermetic unit 71.Another axial end of supporting part 72 is fixed on the interior perimembranous of spring seat 51.Supporting part 72 for example is fixed on the spring seat 51 by press-fiting methods such as cooperation, welding.Ring body 73 applies an inside diametrically clamping force, thereby is radially urging to head on hermetic unit 71 on the inward direction.In this manner, hermetic unit 71 supported parts 72 are supporting, and are pushed up on the path part 43 of plunger 40 by short.As depicted in figs. 1 and 2, plunger 40 from lower dead centre to the process of upper dead center motion, oil sealing 70 is engaging with the path part 43 of plunger 40.

Make with the material of elastically deformable on the hermetic unit 71, such material for example is rubber material or resin material.The inner peripheral surface of hermetic unit 71 has formed a slidingsurface 71a, and its outer circumferential face with plunger 40 path parts 43 is engaging hermetically.Fuel after being pressurizeed in pressurized chamber 33 can partly leak into the outside of housing body 32 through the sliding area between plunger 40 and the housing body 32, specifically, can leak into drive unit 60 sides of housing body 32.Leak into fuel between plunger 40 and the housing body 32 can play lubricant oil between these two effect.

In contrast, lubricant oil is gone out stream from drive unit 60 1 sides and is given tappet 54, is beneficial to the slip of tappet 54 with respect to tappet guide 53.Like this,, be full of lubricant oil in the space of supporting part 72 outsides, then be full of fuel in supporting part 72 volume inside at oil sealing 70 places.Hermetic unit 71 is engaging hermetically with the path part 43 of plunger 40, thereby oil sealing 70 has limited the mutual mixing of Fuels And Lubricants.Utilize a return flow line (not shown), the fuel that fills in oil sealing 70 supporting parts 72 inner spaces is for example by strile-back hopper and/or go into circulation road 28 of foldback.

On housing body 32, be provided with one and go out to flow valve system 80.Go out to flow valve system 80 and comprise a shell 81.Housing body 32 has formed a fuel and has gone out circulation road 37, and it is communicated with pressurized chamber 33.Housing body 32 has a tubular portion 38, and it is positioned at the radial outside of circulation road 37.Shell 81 is made into tubular body, and it is admitting one to go out to flow valve 90.An axial end of shell 81 is fixed on the tubular portion 38.In this embodiment, shell 81 for example is fixed on the housing body 32 by being threaded.Shell 81 has a receiving portion 82, and wherein has a fuel channel 83.Receiving portion 82 is being admitted and to flow valve 90.

Going out to flow valve 90 is installed in the shell 81.Go out to flow valve 90 and comprise that a valve body 91, a valve member 92, a passage form a member 93 and a spring 94.Valve body 91 is made into tubular body, and is set at the inside of shell 81.On valve body 91, be shaped on a fuel channel 95, its with go out circulation road 37 and be communicated with.Sealably roof pressure is on an end of valve body 91 for valve member 92, and this end is positioned at passage and forms member 93 1 sides.Passage forms member 93 and is disposed on the valve body 91 on the opposition side opposite with housing body 32.Valve member 92 is made into disc-shaped bodies, and it can form axial direction to-and-fro motion in passage formation member 93 of member 93 along passage.Spring 94 is with valve member 92 short tops to valve body 91 1 sides.

If by the fuel in the pressurized chamber 33 pressurization being made on the valve body 91 and the pressure rising that goes out the fuel channel 95 that circulation road 37 is communicated with, then the short top power of fuel will increase in the fuel channel 95, this short top power applies kinetogenesis to valve member 92.Like this, if the active force that is applied by fuel in the fuel channel 95 becomes greater than the active force that is imposed on valve member 92 by fuel in the fuel channel 83 and spring 94, then valve member 92 just will be lifted away from valve body 91.In this manner, the fuel channel 83 that goes out circulation road 37 and shell 81 just will be interconnected, thereby the fuel after the pressurization is just transported out from high pressure fuel pump 10.In contrast, if the pressure of fuel channel 83 greater than the pressure that goes out circulation road 37, then valve member 92 is just being pressed seat valve body 91, thereby just stops fuel to flow to out circulation road 37 from fuel channel 83.That is to say, go out to flow the effect that valve 90 has played check valve, its allow fuel from the pressurized chamber 33 1 effluents to the outside of high pressure fuel pump 10.

In high pressure fuel pump 10, plunger 40 and tappet 54 move back and forth between upper dead center shown in Figure 2 at lower dead centre shown in Figure 1 according to the rule of pump cam 62 cam profiles.When plunger 40 when upper dead center moves to lower dead centre, solenoid valve 11 is unlocked.Thereby the fuel of prearranging quatity just is transported to the pressurized chamber 33 from going into circulation road 28.When plunger 40 from lower dead centre when upper dead center moves, the fuel in the pressurized chamber 33 is discharged in the circulation road 28.If the fuel of prearranging quatity will be discharged to the circulation road 28 from pressurized chamber 33, then solenoid valve 11 cuts out.When plunger 40 moved upward, the fuel in the pressurized chamber 33 was pressurizeed.When the pressure in pressurized chamber 33 was increased, the pressure that goes out fuel in the circulation road 37 also was increased.Become greater than the pressure of fuel in the fuel channel 83 if go out the pressure of fuel in the circulation road 37, then going out to flow valve 90 will be opened.Like this, fuel will be from the pressurized chamber 33 outsides that are discharged to high pressure fuel pump 10,

In the first embodiment, oil sealing 70 engages with the path part 43 of plunger 40.Thereby, even plunger 40 large-diameter portions divide 42 the external diameter and the internal diameter of cylinder 36 to be increased, also need not to change the diameter of the oil sealing 70 that engages with path part 43.The result is exactly, and for example requiredly goes out flow by what change that plunger 40 large-diameter portions divide that 42 external diameters and cylinder 36 internal diameters change high pressure fuel pump 10 even changed concrete index one, also do not need to change the design of oil sealing 70.In addition, owing to the design that need not to change oil sealing 70 along with the change of plunger 40, thus can prevent increasing of oil sealing 70 product numbers and increasing of oil sealing 70 mfg. moulding die product numbers, and can reduce the number of steps that is used to test oil sealing 70 performances.

In addition, in the first embodiment, oil sealing 70 engages with the path part 43 of plunger 40.Thereby even plunger 40 large-diameter portions divide 42 external diameter increase, the total length of contact area can not change yet between plunger 40 and the oil sealing 70.Thereby, even plunger 40 large-diameter portions divide 42 diameter to enlarge markedly, also can easily reach requirement to sealability between plunger 40 and the oil sealing 70.In addition, do not need to apply very big active force so that oil sealing 70 is pressed onto on the plunger 40 yet.Thereby, the friction between oil sealing 70 and the plunger 40 can be reduced, thereby reliability and serviceability can be improved.

In addition, according to first mode of execution, can under the prerequisite that does not change path part 43 external diameters, increase large-diameter portion and divide 42 external diameter.Thereby even large-diameter portion divides 42 external diameter increase, the increase of plunger 40 gross weights is also limited.If the weight of plunger 40 increases, then plunger 40 its inertia when carrying out to-and-fro motion will increase.As in the first embodiment like this, coming by pump cam 62 under the situation of drive plunger 40, if the inertia of plunger 40 becomes excessive, then plunger 40 and tappet 54 are followed the just decline of ability of pump cam 62 cam profiles, and then make the ability of carrying out axially reciprocating impaired.Follow the ability of pump cam 62 cam profiles in order to improve plunger 40 and tappet 54, just need to increase the short top power of piston spring 50.The increase of piston spring 50 short top power will cause the size of piston spring 50 significantly to strengthen.If the size of piston spring 50 significantly strengthens, then the size of tappet 54 and being used to admits the size of the tappet guide 53 of tappet 54 also will correspondingly obviously increase.In addition, if the short top power of piston spring 50 increases, then drive unit 60 is used for drive plunger 40 and tappet 54 required driving forces will increase.Like this, the size of drive unit 60 also needs significantly to strengthen, to reach required driving force.Thereby the overall dimension of high pressure fuel pump 10 need enlarge markedly, to be adapted to the increase of plunger outer diameter.But,,, also can limit the increase of plunger 40 gross weights to the full extent even large-diameter portion divides 42 external diameter to be increased according to first mode of execution.The result is exactly, and need not to enlarge markedly the size of piston spring 50, thereby, limited the obvious increasing of high pressure fuel pump 10 sizes.

(second to the 5th mode of execution)

Fig. 3 has represented second to the 5th mode of execution of the present invention respectively to Fig. 6.In the following description, will refer to identical number designation with the similar parts of first mode of execution, and for brevity, no longer be repeated in this description.

As shown in Figure 3, in second mode of execution, the shape of oil sealing is different with shape in first mode of execution.Compare with the situation in first mode of execution, in second mode of execution, housing body 32 is extended to drive unit 60 1 sides further.The end that is positioned at drive unit 60 1 sides on the housing body 32 has one and admits chamber 321, and it caves in to pressurized chamber's 33 1 sides.Oil sealing 170 is disposed in the admittance chamber 321 of housing body 32.Oil sealing 170 comprises a hermetic unit 171, a supporting part 172 and a ring body 173.Hermetic unit 171 has a slidingsurface 171a, and its outer circumferential face 43a with plunger 40 path parts 43 is engaging slidably.One end of supporting part 172 is supporting hermetic unit 171.The other end of supporting part 172 is fixed on the housing body 32.Methods such as housing body 32 for example cooperates by press-fiting with supporting part 172, welding securely couple together mutually.According to second mode of execution, the line shaft that can reduce oil sealing 170 upper support parts 172 is to length.

As shown in Figure 4, in the 3rd mode of execution, the shape of oil sealing is different with shape in first mode of execution.Compare with the situation in first mode of execution, in the 3rd mode of execution, housing body 32 is extended to drive unit 60 1 sides further.The end that is positioned at drive unit 60 1 sides on the housing body 32 has one and admits chamber 322, and it caves in to pressurized chamber's 33 1 sides.Oil sealing 270 is set in the admittance chamber 322 of housing body 32.Oil sealing 270 comprises a hermetic unit 271 and a ring body 273.Ring body 273 is mounted in the groove 323 of housing body 23.In this manner, ring body 273 is supporting hermetic unit 271 from a side opposite with pressurized chamber 33.According to the 3rd mode of execution, can cancel on the oil sealing and corresponding that part of supporting part.The result is exactly to reduce the number of parts.

As shown in Figure 5, in the 4th mode of execution, the mounting type of oil sealing is different with situation in first mode of execution.In the 4th mode of execution, the supporting part 72 of oil sealing 70 is installed on the housing body 32, but not is installed on the spring seat 51.That is to say that supporting part 72 for example is fixed on the peripheral part of housing body 32 by press-fiting methods such as cooperation, welding.

As shown in Figure 6, in the 5th mode of execution, the shape of plunger 40 is different with shape in first mode of execution.Compare with the situation in first mode of execution, in the 5th mode of execution, the large-diameter portion of plunger 40 divides 42 to be strengthened.As shown in Figure 6, if the size that enlarges markedly plunger 40 is to improve from the flow fuel of high pressure fuel pump 10 outputs, the large-diameter portion that then can further obviously strengthen plunger 40 divides 42.In the case, on plunger 40, have only large-diameter portion to divide 42 external diameter to be increased, the external diameter of path part 43 is retained as steady state value.Thereby, need not oil sealing 70 is designed, and the total length of area of contact can not increase between plunger 40 and the oil sealing 70, the weight of plunger 40 can not increase yet.

(the 6th mode of execution)

Fig. 7 has represented the high pressure fuel pump according to sixth embodiment of the invention.In the following description, will refer to identical number designation with the similar parts of first mode of execution, and for brevity, no longer be repeated in this description.

As shown in Figure 7, in the 6th mode of execution, the shape of oil sealing is different with shape in first mode of execution.According to the 6th mode of execution, oil sealing 370 comprises hermetic unit 371 and supporting part 372.One end of supporting part 372 is supporting hermetic unit 371.The interior perimembranous of hermetic unit 371 has formed a slidingsurface 371a.The other end opposite with hermetic unit 371 on the supporting part 372 comprises a standing part 373.Standing part 373 is directly mounted on the housing body 32.Housing body 32 comprises a tubular portion 324, and its projection is to valve cam 61 1 sides.Tubular portion 324 is made into tubular body, and it is communicated with cylinder 36.Standing part 373 couples together with tubular portion 324.Standing part 373 for example is fixed on the tubular portion 324 of housing body 32 by press-fiting methods such as cooperation, welding.

When plunger 40 was in lower dead centre shown in Figure 7, standing part 373 was positioned at camshaft 61 sides that large-diameter portion divides close valve camshaft 61 1 side ends on 42.Lower dead centre is meant such position: on this position, plunger 40 is in the position of below with respect to valve camshaft 61, thereby, make the volume maximum of pressurized chamber 33.If set the position of standing part 373 in the manner described above, then the large-diameter portion of plunger 40 divides 42 just can not move valve camshaft 61 1 sides that exceed standing part 373 and be in standing part 373.

Under oil sealing 370 was fixed directly to situation on the housing body 32, standing part 373 was press-fited or is welded on the housing body 32.Be performed at standing part 373 and press-fit or when welding, the tubular portion 324 on the housing body 32 may deform in some cases.If distortion has taken place housing body 32, then guiding the cylinder 36 of plunger 40 to be out of shape in it, thereby having influence on the smooth motion of plunger 40.Thereby in the first embodiment, supporting part 372 is fixed on the spring seat 51, and spring seat 51 be made into housing body 32 be what to be separated.In this manner, in the first embodiment, because supporting part 372 has been fixed on the spring seat 51, so even spring seat 51 can deform, the distortion of housing 32 also can be restrained effectively.

In the 6th mode of execution, if standing part 373 is fixed directly on the tubular portion 324 of housing body 32, then distortion slightly may appear in tubular portion 324.But as mentioned above, when plunger 40 was in lower dead centre, standing part 373 was positioned at valve camshaft 61 sides that large-diameter portion divides valve camshaft 61 side ends on 42.Thereby, when plunger 40 is carried out to-and-fro motion.The large-diameter portion of plunger 40 divides the inner radial that can not enter into standing part 373.Thereby, have only the path part 43 of plunger 40 can move to the radially inner side of standing part 373.The result is that even housing body 32 deforms, plunger 40 large-diameter portions divide the slide relative between 42 peripheral edge 42a and cylinder 36 inner peripheral surfaces also can not be affected, thereby plunger 40 level and smooth to-and-fro motion can not be affected.

In addition, in the 6th mode of execution, oil sealing 370 can be fixed directly on the housing body 32.Thereby, not needing to be provided with the spring seat 51 in first mode of execution of a special individual components-for example, these parts can limit the distortion of housing body 32.In this manner, many parts-for example be used to limit the parts of housing body 32 distortion and the sealing component that is used for sealing all is unnecessary between this distortion restrain unit and other parts (for example housing body 32).The result is exactly to reduce the number of parts and the number of number of assembling steps.

(the 7th to the 9th mode of execution)

Fig. 8 has represented the high pressure fuel pump of the 7th to the 9th mode of execution respectively to Figure 10.In the following description, will refer to identical number designation with the similar parts of first mode of execution, and for brevity, no longer be repeated in this description.

As shown in Figure 8, in the 7th mode of execution, oil sealing 470 comprises a hermetic unit 471 and a retainer 472.Hermetic unit 471 is held device 472 and is keeping.Similar with the 6th mode of execution, retainer 472 is fixed directly on the housing body 32.For example retainer 472 is fixed on the housing body 32 by press-fiting methods such as cooperation, welding.Hermetic unit 471 is arranged on two axial positions along plunger 40.Each sealing component 471 can be rubber seal member (for example O shape circle or X-shaped circle) or resin seal member, and resin seal member wherein can be made into ring shape.

As shown in Figure 9, in the 8th mode of execution, oil sealing 570 comprises a hermetic unit 571 and a retainer 572.Hermetic unit 571 is held device 472 and is keeping.Retainer 572 is fixed directly on the interior perimembranous of housing body 32.For example retainer 572 is fixed on the housing body 32, perhaps utilizes a ring body 580 keeping retainer 580 by press-fiting methods such as cooperation, welding.Sealing component 571 is not limited to the form of rubber seal member.For example, sealing component 571 can be a resin seal member.

As shown in figure 10, in the 9th mode of execution, oil sealing 670 comprises

hermetic unit

671 and 672, supporting parts 673 and a retainer 674.Hermetic unit 671 supported parts 673 are supporting, and hermetic unit 672 is held device 674 and is keeping.Supporting part 673 and retainer 674 are fixed on the interior perimembranous of housing body 32.Retainer 674 is being kept by housing body 32.For example utilize and press-fit methods such as cooperation, welding supporting part 673 is fixed on the housing body 32.In the 9th mode of execution, sealing component 671 is rubber seal members, and sealing component 672 is resin seal member.As discussed abovely like that can adopt the assemblying body of different sealing member, these sealing components are respectively to make with different materials.

The present invention is not limited to above-mentioned embodiment, under the prerequisite departing from the scope of the invention not, can implement the present invention according to variety of way.

Those skilled in the art can easily recognize other advantage and remodeling.Thereby in broad aspect, the present invention is not limited in the literary composition expression and the example of detail, representative device and the example shape of describing.In addition, should be noted that: the parts of arbitrary mode of execution all can be replaced by the parts in other mode of execution in above-mentioned each mode of execution, or make up, and this does not exceed design philosophy of the present invention and scope.

Claims

1, a kind of high pressure fuel pump, it comprises:

Housing (31,32) has formed cylinder (36) in the described housing, cylinder (36) and the fuel in the housing (31,32) are gone into circulation road (28) and fuel and gone out circulation road (37) and be communicated with;

Plunger (40), plunger can be supported in the cylinder (36) slidingly back and forth and comprise:

Axial end (41), it matches with housing (31,32) and defines pressurized chamber (33), and wherein plunger (40) pressurizes to the fuel in pressurized chamber (33);

Large-diameter portion branch (42), it has an outer circumferential face (42a), and its inner peripheral surface (32a) with housing (31,32) engages slidably, and wherein this inner peripheral surface forms described cylinder (36); And

Path part (43), its external diameter are less than the external diameter of large-diameter portion branch (42), and the path part is connected with the last opposite axial end of plunger (40), and this axial end present position is opposite with large-diameter portion branch (42) with pressurized chamber (33);

Drive unit (60), it is used for reciprocally drive plunger (40), and wherein, drive unit (60) is set at the opposite shaft orientation end place of plunger (40), and this opposite shaft orientation end is opposite with pressurized chamber (33); And

Seal arrangement (70,170,270,370,470,570,670), it has slidingsurface, engages to outer circumferential face (43a) fluid-tight of described slidingsurface and path part (43).

2, high pressure fuel pump according to claim 1 is characterized in that: also comprise:

Resilient member (50), it urgees the top to drive unit (60) one sides with plunger (40); And

Bearing (52), its short top power with resilient member (50) passes to plunger (40), wherein, plunger (40) also comprises diameter shrinkage part (44), it engages with bearing (52), and be positioned at an opposite ends place on the path opposite with large-diameter portion branch (42) part (43), and the external diameter of diameter shrinkage part (44) is less than the external diameter of path part (43).

3, high pressure fuel pump according to claim 2 is characterized in that: the external diameter of diameter shrinkage part (44) is equal to or greater than 3mm.

4, high pressure fuel pump according to claim 1 is characterized in that:

Seal arrangement (70,170,270,370,470,570,670) comprises standing part (373), and it is fixed on the housing (31,32); And

When plunger (40) when being in lower dead point position, standing part (373) is than the more close drive unit of drive unit side end (60) of large-diameter portion branch (42).

5, high pressure fuel pump according to claim 1 is characterized in that: in a side opposite with the pressurized chamber (33) of cylinder (36), seal arrangement (70,370,470) is positioned at the axial outside of housing (31,32).