DE102008040242A1 - Injection pump for injecting diesel fuel into internal combustion engine in motor vehicle, has double-C-frame supported on rolling body tracks by rolling bodies, which are rolled off on rolling body tracks in peripheral direction - Google Patents

Abstract

The pump has a cylinder head (1) comprising a cylinder bore in which a piston (2) is held. The piston is movable to and fro by an eccentric cam of a drive shaft (6), which is rotated around an axis. A double silencer comprises two pot-like edges (4.2) that extend parallel to the axis. The pot-like edges are defined radially at inner and outer sides of rolling body tracks. A double-C-frame is supported on the rolling body tracks by rolling bodies (7.1, 7.2), where the rolling bodies are rolled off on the rolling body tracks in a peripheral direction.

Description

Technical area

The The invention is based on an injection pump, in particular of a Injection pump according to the preamble of claim 1.

State of the art

Such an injection pump is out of the DE 19515191 A1 known. The piston is supported on the outside facing him facing an eccentric and resiliently pressed by the force of a pressure spring acting on it. With a rotating eccentric he therefore follows the radial relative movements of the eccentric, which is used to suck fuel into the pump room to compact it and via a high pressure valve into a high-pressure collector to be connected to the various injectors of an internal combustion engine, the Einsprit tion of the highly compressed fuel into the combustion chambers of the internal combustion engine effect.

requirement for a correct function are the compression springs. These are very voluminous designed and they need therefore a lot of space. In addition, the production and Assembly of the pressure springs consuming. You need to be installed in a prestressed condition. There is therefore a desire to be able to dispense with the installation of such springs.

Disclosure of the invention

Advantages of the invention

The injection pump according to the invention with the features according to claim 1 has the advantage that compression springs for the proper functioning of the Injection pump is no longer needed. This accounts also the problems of the installation needed Space, assembly and material fatigue and a insufficient elasticity due to persistent, mechanical Load at an elevated temperature stress. Besides that is it is no longer necessary during normal use the injection pump constantly compress a preloaded compression spring and subsequently relieve it again. This results in a considerable Fuel savings.

In the dependent claims are advantageous embodiments and further developments of the injection pump according to the invention specified.

In The training according to claim 2 is a design shown to be particularly robust in terms of generating highest Pressures of more than 2000 bar and that is very easy to assemble and disassemble.

By The embodiment according to claim 3 becomes a design shown, which has an extremely good longevity at the highest Having pumping pressures. The with the radially outer Peripheral surface engaging roller or rollers have a greater length than the inside lying roles together. The one on the at least one, outside lying over the roller for the high pressure compression the forces required to transmit the fuel, is therefore subject to a lower specific surface pressure as the radially inner rollers over which only the needed for the suction stroke of the injection pump, transmitted much lower forces.

In The embodiment according to claim 4 is a design shown, which is particularly easy to install producible.

In The embodiment according to claim 5 is a design shown, which is easy to assemble and during their use form-fitting correctly together. Also vibrations can not endanger the cohesion.

The Training according to claim 6 has the advantage that the piston in essential Relieved from shear forces in the high-pressure compression be transmitted by fuel from the drive shaft can.

By The embodiment according to claim 7 is achieved, that the rolling elements Touch the roller tracks under all operating conditions without play. The Occurrence of rattling noises is excluded and always a complete filling of the pump room with fresh fuel and a consistent pumping action guaranteed.

By The embodiment according to claim 7 achieves the advantage that the Flow rate can be increased cost-effectively and without on a further or larger injection pump to have to fall back.

drawing

One Embodiment of the invention is in the drawing shown. It will be explained in more detail below. Show it:

The 1 an injection pump in cross-sectional view, in which the piston touches the edge of the cup with rolling elements radially inside and outside in the range of raceways;

the 2 after the injection pump 1 in longitudinal section.

Description of the embodiment

In the 1 and 2 shown injection pump for diesel fuel is intended for the supply of an internal combustion engine. It can be used in a motor vehicle. The fuel is supplied to the injection pump by a fuel pump, not shown, with a pre-pressure of about 3 bar and fed via a suction valve in the pump chamber, while the piston moves down. In the following working cycle, the suction valve closes and the fuel is pressed under high pressure of up to 2000 bar via a high pressure valve from the pump room and fed into a high-pressure collector. The suction and the high pressure valve may be formed as a spring-loaded check valves. They make sure that the fuel is the pump room 3 just in the direction of in 1 marked arrows can happen. When Sauhub opens only the suction valve and the working stroke, only the high pressure valve, which leads to the passage of fuel through the pump room 3 leads in the direction of the arrow. To the high-pressure accumulator injectors, also not shown, are connected, which cause the injection of the fuel into the combustion chambers of the internal combustion engine. The flow direction of the fuel is in 2 through the injection pump is indicated by arrows.

In The following detailed description refers to the same Reference numerals of the figures matching objects.

The illustrated injection pump comprises a cylinder head 1 with a cylinder bore, in which a piston 2 is received, with the one end a pump room 3 limited and projecting beyond the cylinder bore with the other end and by an eccentric facing him one about an axis 5 rotating drive shaft 6 in the direction of the pump room 3 can be moved back and forth.

The eccentric forms part of a non-rotatable on the drive shaft 6 fixed double pot 4 , which in the region of the outer periphery by two in the axial direction mirror image outwardly projecting pot edges 4.2 is limited, which is parallel to the axis 5 extend and the radially inside and outside by Wälzkörperlaufbahnen 4.3 . 4.4 are limited, wherein the cylinder bore projecting end of the piston 2 the axially projecting pot edges 4.2 of the double pot 4 with a mirror image axially in the direction of the two pot edges 4.2 U-shaped double C-bar 7 engages radially inside and outside, wherein the double C-bracket 7 by rolling elements ( 7.1 . 7.2 ) on the radially inner and outer side rolling element raceways 4.3 . 4.4 is supported and wherein the rolling elements 7.1 . 7.2 in the circumferential direction on the Wälzkörperlaufbahnen 4.3 . 4.4 are rebated.

The drive shaft 6 is over the double pot 4 extended axially and on the opposite side of the double pot 4 in an additional, second support bearing of the housing 8th stored and rotated stored. Deflections of the drive shaft 6 in the area of the double pot 4 or the occurrence of vibrations in the the double pot 4 supporting end of the drive shaft 6 is countered by this.

The double pot 4 is integrally formed. It can be made entirely of hardened steel or, alternatively, an oval hardened steel tire shrunk onto a support flange made of unhardened steel.

With rotating drive shaft 6 move the raceways of the double pot at the piston 2 facing circumferential point successively on the axis 5 the drive shaft 6 to and from it again. This relative movement is due to the rolling elements and the double C-bracket 7 on the piston 2 transferred, causing the piston 2 alternately in the radial direction on the axis 5 the drive shaft 6 moved away from and to. Accordingly, the pump space increases and decreases 3 the injection pump with rotating drive shaft cyclically consecutive, which is used to fuel in the pump room 3 suck in, compress it and feed under high pressure in a pressure collector.

The rolling elements 7.1 . 7.2 are in the design after 1 and 2 by rollers and the rolling element rolling tracks by roller tracks 4.3 . 4.4 educated. As a result, larger forces can be transmitted than with balls and thus achieve higher pump pressures.

The roller tracks 4.3 . 4.4 have parallel to the axis 5 a length equal to that of each roll thereafter rollable 7.1 . 7.2 essentially coincides. For the high-pressure compression of diesel fuel are therefore large specific wings of the roles 7.1 available, which allows to achieve the highest pressures. For this purpose, those with the radially outer roller track 4.4 in suitable standing roles 7.1 have a larger diameter and a greater overall length than the much less loaded, inner rollers 7.2 , which are needed only for the suction stroke. The diameter of the outer rollers 7.1 can be 2 to 5 times larger than that of the inside rollers 7.2 ,

The double C-hanger 7 consists of a fixed to the piston end support plate and two C-arms, with facing C-opening to the transverse to the axis 5 extending end faces of the support plate 2.1 are fixed. The C-hanger 7 are on the of the support plate 2.1 opposite sides of one with the end of the piston 2 connected support sleeve 2.2 overstretched and thereby to the support plate 2.1 pressed.

The support sleeve 2.2 is cylindrical in a partial region and parallel to the longitudinal direction of the piston 2 on a cylindrical guide surface of the cylinder head 1 or one with the cylinder head 1 slidably connected pump housing. The first-mentioned design is preferred within the scope of the invention because this results in a completely concentric assignment of the support sleeve 2.2 to the axis of the piston 2 easier to ensure.

The radially inner rolling elements 7.2 are through the double C-hanger 7 in the radial direction resiliently to the Wälzkörperlaufbahnen 4.3 pressed. As a result, it is imposed that game arises and it is achieved that the injection pump generates a clearly defined flow rate and performance under all operating conditions, even after a long service life. Of course, deviating from the illustration, also several circumferentially distributed ends of pistons 2 the peg edges facing them 4.2 of the double pot 4 with axial in the direction of the two pot edges 4.2 U-shaped double C-arms 7 encompass radially inside and outside, with the respective double C-bracket 7 through rolling elements 7.1 . 7.2 on the radially inner and outer side rolling element raceways 4.3 . 4.4 are supported and wherein the rolling elements 7.1 . 7.2 in the circumferential direction on the Wälzkörperlaufbahnen 4.3 . 4.4 are rebated. In accordance with the number of sub-pumps used, this makes it possible to multiply the delivery rate by using modularly assembled components and to use the injection pump for engines of different sizes, which is of great economic advantage.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19515191 A1 [0002]

Claims (9)

Injection pump for diesel fuel, comprising a cylinder head ( 1 ) with a cylinder bore in which a piston ( 2 ), which at one end has a pump space ( 3 ) is limited and projects beyond the cylinder bore with the other end and by an eccentric facing it one about an axis ( 5 ) rotating drive shaft ( 6 ) in the direction of the pump chamber ( 3 ) is reciprocable, characterized in that the eccentric part of a double pot ( 4 ), which in the region of the outer periphery by two in the axial direction mirror image outwardly projecting pot edges ( 4.2 ) parallel to the axis ( 5 ) and the radially inside and outside by Wälzkörperlaufbahnen ( 4.3 . 4.4 ) are limited, that the cylinder bore projecting end of the piston ( 2 ) the axially projecting pot edges ( 4.2 ) of the double pot ( 4 ) with an axial in the direction of the two pot edges ( 4.2 ) U-shaped double C-bar ( 7 ) radially inwardly and externally surrounds that the double C-bracket ( 7 ) by rolling elements ( 7.1 . 7.2 ) on the radially inner and outer side Wälzkörperlaufbahnen ( 4.3 . 4.4 ) of the pot edges ( 4.2 ) is supported and that the rolling elements ( 7.1 . 7.2 ) in the circumferential direction on the Wälzkörperlaufbahnen ( 4.3 . 4.4 ) are rollable. Injection pump according to claim 1, characterized in that the rolling bodies ( 7.1 . 7.2 ) by rollers and the rolling element raceways ( 4.3 . 4.4 ) are formed by roller raceways. Injection pump according to claim 2, characterized in that the diameter of the outer rollers ( 7.1 ) 2 to 5 times as that of the internal rollers ( 7.2 ). Injection pump according to claim 2 or 3, characterized in that the rolling body raceways ( 4.3 . 4.4 ) parallel to the axis ( 5 ) have a length which substantially coincides with that of the respective rollers which can be rolled on it. Injection pump according to one of claims 1 to 4, characterized in that the double C-bracket ( 7 ) from a support plate fixed to the piston end ( 2.1 ) and two C-arms, with facing C-opening at the transverse to the axis ( 5 ) extending end faces of the support plate ( 2.1 ). Injection pump according to claim 5, characterized in that the C-brackets on the of the support plate ( 2.1 ) facing away from one with the end of the piston ( 2 ) associated support sleeve ( 2.2 ) and to the support plate ( 2.1 ) are pressed. Injection pump according to claim 6, characterized in that the support sleeve ( 2.2 ) is cylindrical in a partial region and parallel to the longitudinal direction of the piston ( 2 ) on a cylindrical guide surface of the cylinder head ( 1 ) or one with the cylinder head ( 1 ) connected pump housing ( 8th ) is displaceable. Injection pump according to one of claims 1 to 7, characterized in that the radially inner rolling elements ( 7.2 ) through the double C-bracket ( 7 ) in the radial direction resiliently to the Wälzkörperlaufbahnen ( 4.3 . 4.4 ) are pressed. Injection pump according to one of claims 1 to 8, characterized in that a plurality of circumferentially distributed ends of piston ( 2 ) the pot edges ( 4.2 ) of the double pot ( 4 ) with a U-shape in the direction of the two pot edges ( 4.1 . 4.2 ) opened double C-ironing ( 7 ) radially inward and outward embrace that the double C-bracket ( 7 ) by rolling elements ( 7.1 . 7.2 ) on the radially inner and outer side Wälzkörperlaufbahnen ( 4.3 . 4.4 ) are supported and that the rolling elements ( 7.1 . 7.2 ) in the circumferential direction on the Wälzkörperlaufbahnen ( 4.3 . 4.4 ) are rollable.