DE102008054753A1 - Internal gear pump - Google Patents

Abstract

An internal gear pump (14) has an internal rotor (100) which can be driven rotatably about a drive axis (104). It is proposed that the inner rotor (100) can be driven by means of a shaft (48) which can be supported or mounted in an internal combustion engine (12) and which has a shaft section (114) rotatable about the drive axis (104) of the inner rotor (100) for driving the inner rotor (100).

Description

State of the art

The The invention relates to an internal gear pump according to the preamble of Claim 1.

From the DE 10 2006 056 844 A1 is an internal gear pump for conveying a hydraulic fluid known, with a gear pair and at least two pressure outlets on the pressure side of the internal gear pump. In this way, with the help of an internal gear pump, which has only a few components, a flow rate can be varied.

Disclosure of the invention

task the present invention is to provide an internal gear pump, which takes up as little space as possible and with as few as possible Components can be produced.

These Task is by an internal gear pump with the characteristics of Claim 1 solved. Advantageous developments are in specified in the dependent claims. Furthermore find for the invention important features in the subsequent description and in the drawing, wherein the features both alone and in different combinations may be important to the invention without This is again explicitly pointed out.

By Use of a shaft portion of a in an internal combustion engine storable or mounted shaft for the rotary drive of Inner rotor claims the internal gear pump according to the invention very little space. This internal gear pump needed no usually provided, separate drive / bearing shaft. This also eliminates the need for large-scale Be wegungsübertragungseinrichtungen or coupling elements (for example a belt drive) to provide a movement of a drive to transfer to a separate drive / bearing shaft. Much more claims the internal gear pump according to the invention in Radial direction substantially only one shaft portion surrounding space. In the axial direction of the shaft optionally results in a based on the overall dimensions of the internal combustion engine only insignificant Renewal.

Of the Waiving a separate drive shaft and the possibility dispense with further motion transmission devices Being able to do that does not just mean reducing the number the components of the internal gear pump itself, but also a reduction the number of components of the entire assembly of internal combustion engine and internal gear pump.

In Advantageously, the shaft is a camshaft or a crankshaft or a balancer shaft of the internal combustion engine. A Rotational movement of such a shaft can be directly related to a rotational movement of the inner rotor are transmitted.

Prefers it is when the shaft portion by a in the axial direction of the Shaft seen is formed free shaft end, which with the inner rotor connectable or connected. It is conceivable that under Maintaining the dimensions of a housing of the internal combustion engine the shaft is extended so that a free shaft end over the Housing of the engine protrudes and this protruding End is used as a shaft portion for driving the inner rotor.

Prefers it is also when the shaft end in a central opening the inner rotor is inserted or inserted. Compared to a possible connection in principle an end face of the shaft end and the inner rotor has the insertion of the shaft end in a central opening of the inner rotor the advantage that space can be saved in the axial direction can. This allows a particularly compact design a housing of the internal gear pump.

If a joining direction for connecting the shaft and the inner rotor kotlinear to the drive axis of the inner rotor, This results in a particularly simple installation of the internal gear pump.

To An embodiment of the invention is the internal gear pump designed as a sickle-internal gear pump. This allows a compact internal gear pump provided with a particularly good volumetric efficiency become.

To an alternative embodiment of the invention is the Internal gear pump designed as a sickle-free internal gear pump, which also allows a particularly compact design.

A particularly preferred embodiment of the invention provides that the inner rotor is mounted eccentrically to an outer rotor and having a meshing with an inner toothing of the outer rotor outer toothing, and that the inner toothing of the outer rotor is formed by rotatably mounted on the outer rotor rollers. In this way, a achieved by the engagement of the external teeth with the internal teeth sealing effect is improved. Such an arrangement may also be referred to as a "planetary rotor set". A further improvement of the sealing effect can be achieved when the rollers have a roller Feinver have toothing, and when the outer toothing of the inner rotor is superimposed on a corresponding inner rotor fine toothing.

The The invention further relates to an internal combustion engine with an above described internal gear pump.

Further The invention relates to a fuel injection system for an internal combustion engine comprising an above-described Internal gear pump.

following Be embodiments of the invention with reference explained in the accompanying drawings. In the drawing demonstrate:

1 a schematic view of a fuel injection system with an internal combustion engine and with an internal gear pump for the delivery of fuel;

2 a sectional side view of the internal gear pump according to 1 in an enlarged view;

3 one of the 2 corresponding view during assembly of the internal gear pump to the internal combustion engine;

4 a plan view of a first embodiment of a gear arrangement of the internal gear pump according to 1 ; and

5 a plan view of a further embodiment of the gear arrangement of the internal gear pump according to 1 ,

An Indian 1 total with the reference numeral 10 designated fuel injection system for supplying an internal combustion engine 12 with fuel includes an internal gear pump 14 ,

The fuel injection system 10 has a reservoir 16 for storing fuel. With the help of a pre-feed pump 18 , which preferably by means of a controllable drive device, in particular in the form of an electric motor 20 is driven, fuel is from the reservoir 16 in a low pressure line 22 promoted. By the use of a controllable drive device for the prefeed pump 18 can the flow rate of the fuel injection system 10 be adjusted so that production losses can be reduced, which results by promoting an excess amount of fuel, which then back into the reservoir 16 must be returned.

To limit the fuel pressure in the low pressure line 22 is a low pressure relief valve 24 provided by means of which when exceeding a predetermined maximum pressure fuel from the low pressure line 22 back to the reservoir 16 to be led.

The low pressure line 22 flows at an entrance 26 the internal gear pump 14 , This acts on the over the entrance 26 supplied fuel with high pressure. The high-pressure fuel passes through an outlet 28 the internal gear pump 14 to a high pressure line 30 which to egg ner fuel collection device in the form of a rail 32 leads. The rail 32 supplies injectors 34 with pressurized fuel. The injectors 34 are each one of the combustion chambers of the internal combustion engine 12 assigned and allow a direct injection of the fuel into the combustion chambers.

The pressure in the rail 32 is done with the help of a pressure sensor 36 detected. A voltage signal corresponding to the detected pressure can be detected by means of a data line 38 a control unit 40 be supplied. The control unit 40 is by means of a control line 42 with the electric motor 20 coupled.

The internal combustion engine 12 includes a partially shown engine case 44 , for example in the form of a cylinder head. The engine case 44 has an outwardly facing housing surface 46 on. Furthermore, the internal combustion engine comprises 12 a wave 48 , in particular in the form of a camshaft, which about a shaft axis 50 rotatable on the engine housing 44 is stored.

In the engine housing 44 is a housing opening 52 provided, which of the shaft 48 is interspersed, leaving a shaft end 54 over the case surface 46 out into the environment of the internal combustion engine 12 extends.

The internal gear pump 14 has a cup-shaped outer casing 56 on, which in particular by means of a welded flange 58 with the engine case 44 is connected, for example by means of a screw connection. The outer housing 56 points in the direction of the internal combustion engine 12 extending housing projection 60 on, which in the housing opening 52 the internal combustion engine 12 is used. The housing projection 60 has a circular cross-section Gehäuseaussparung 62 on which a passage of the wave 48 allows.

The outer housing 56 the internal gear pump 14 and the engine casing 44 are using an annular seal 64 sealed against each other.

In the outer casing 56 a plurality of housing parts are arranged, namely a first housing part 66 , a second housing part adjacent thereto 68 and acting as a housing cover third housing part 70 , The third housing part 70 is with the outer casing 56 welded. It is preferred if the housing parts 66 . 68 and 70 have mutually parallel planar surfaces, so that the housing parts form metallic sealing surfaces with these flat surfaces. It can with the help of the third housing part 70 a sealing force can be generated which the housing parts 66 and 68 in the outer casing 56 pushes.

The first housing part 66 and the second housing part 68 serve to limit a pump chamber in the form of a receiving space 72 in which a gear arrangement 74 is arranged. The gear arrangement 74 forms the actual feed unit of the internal gear pump 14 , The gear arrangement 74 is in the axial direction between the first housing part 66 and the second housing part 68 stored. The first housing part 66 at the same time forms a radial bearing for the gear arrangement 74 ,

The internal gear pump 14 has low pressure side with the input 26 connected low-pressure channel 76 on, which in the third housing part 70 is trained. The low pressure channel 76 leads to a suction kidney 78 , which in the second housing part 68 is trained. The first housing part 66 has one of the shape of the Saugniere 78 corresponding counter kidney 80 on.

Pressure side includes the internal gear pump 14 one with the exit 28 connected high-pressure channel 82 on, which in the third housing part 70 is trained. The high pressure channel 82 is with a print kidney 84 connected, which in the second housing part 68 is trained. In the first housing part 66 is one of the form of the pressure kidney 84 corresponding counter kidney 86 arranged. With the help of opponents 80 and 86 is achieved that the gear arrangement 74 is loaded evenly from both sides with pressure.

Furthermore, the internal gear pump comprises 14 a pressure relief valve 88 , By means of which, when a predeterminable operating pressure is exceeded, a fluid connection between the high-pressure channel 82 and the low pressure channel 76 can be produced. The pressure relief valve 88 is in a connection channel 90 arranged, which is located between the high-pressure channel 82 and the low pressure channel 76 extends. The pressure relief valve 88 has one in the connection channel 90 pressed valve seat 92 , one with the valve seat 92 cooperating valve body 94 and a valve spring 96 on which the valve body 94 against the valve seat 92 suppressed. The connection channel 90 is formed in the form of a blind hole and at its open end by means of a pressed-in plug 98 locked.

The integration of the input 26 and the output 28 and the pressure relief valve 88 in the third housing part 70 allows a substantial waiver of additional sealing elements and thus a further reduction in the number of components of the internal gear pump 14 ,

The gear arrangement 74 has an inner rotor 100 which is eccentric to an outer rotor 102 is stored (see 2 and 4 ). The inner rotor 100 is around the inner rotor 100 assigned drive axle 104 rotatable. The drive axle 104 is kotlinear with the shaft axis 50 the wave 48 ,

The inner rotor 100 has a central opening 106 into which the shaft end 54 the wave 48 is insertable (cf. 3 ).

The wave 48 has a main section 108 on, which is within the engine housing 44 extends. To the main section 108 closes towards the internal gear pump 14 a wave heel 110 on, in particular a spherically shaped wave guiding surface 112 , a wave section 114 and a frontally arranged shaft journal 116 ,

The shaft heel 110 penetrates the housing recess 62 of the outer casing 56 , For sealing the shaft 48 opposite the internal gear pump 14 is a sealing device 118 provided, which is designed in particular in the form of a radial sealing ring. This is inside the housing projection 60 arranged and comprises a schematically illustrated first sealing lip 120 , by means of which an intrusion of oil from the interior of the internal combustion engine 12 in the internal gear pump 14 is prevented in it. Furthermore, the sealing device comprises 118 a second sealing lip 122 , by means of which an outlet of fuel from the interior of the internal gear pump 14 out into the interior of the internal combustion engine 12 is prevented in it.

The waveguide surface 112 is in a cylindrical storage area 124 mounted, which on the first housing part 66 is trained. To the storage area 124 closes one opposite the storage area 124 inclined centering surface 126 by means of which the insertion of the waveguide surface 112 in the storage area 124 is relieved (cf. 3 ).

The shaft section 114 points, for example se a polygonal profile, in particular a square profile. This profile acts with a corresponding profile of the central opening 106 of the inner rotor 100 together. In this way, between the shaft section 114 and the inner rotor 100 a positive, non-rotatable connection can be made.

To the shaft 48 with the internal gear pump 14 to add, be the wave 48 and the internal gear pump 14 in one of the 128 and 130 designated joining directions moved towards each other. The joining directions 128 and 130 are collinear to the drive axle 104 of the inner rotor 100 and to the shaft axis 50 the wave 48 ,

The shaft journal 116 is preferably cylindrical and serves during the insertion of the shaft end 54 in the internal gear pump 14 as another introduction aid. In the simplest case, the internal gear pump 14 on the free end of the shaft 54 attached. By guiding the waveguide surface 112 in the location area 124 a centering effect is achieved, with which a distortion of the inner rotor 100 is prevented. Damage to the sealing device 118 during the joining of the shaft 48 and the inner rotor 100 is prevented by the shaft journal 116 first in the central opening 106 of the inner rotor 100 engages before the shaft shoulder 110 in the housing recess 62 inserted and engaged with the sealing lips 120 and 122 is brought.

The gear arrangement 74 the internal gear pump 14 is in 4 shown. The on the first housing part 68 mounted outer rotor 102 is about an outer rotor axis 132 rotatably; this axis runs parallel to the drive axle 104 of the inner rotor 100 , The drive axle 104 is to the outer rotor axis 132 ver sets so that the inner rotor 100 eccentric to the outer rotor 102 is stored.

The outer rotor 102 has an internal toothing 134 on, which with an external toothing 136 of the inner rotor 100 interacts. The internal toothing 134 of the outer rotor 102 is through a plurality of roles 138 formed, which in each case on the outer rotor 102 provided pocket-shaped recesses 140 are stored.

The roles 138 have a roller fine toothing 142 on, which with an internal rotor fine toothing 144 combs which of the external teeth 136 of the inner rotor 100 is superimposed.

With the help of the wave 48 is the inner rotor 100 in a drive direction 146 rotatably driven. By the meshing engagement of the inner rotor 100 with the roles 138 These are also twisted and thereby take the outer rotor 102 in one of the driving directions 146 corresponding direction of rotation with. In this way, by means of the input 26 the internal gear pump 14 supplied fuel from a suction side 148 to a print page 150 compressed and the output 28 the internal gear pump 14 be supplied.

Instead of in 4 illustrated gear arrangement 74 ("Planetenrotorsatz") can also be a gear arrangement 74 be used, which only an inner rotor 100 and an outer rotor 102 includes, wherein the internal toothing 134 of the outer rotor 102 formed integrally with this. Such an internal gear pump 14 can also be described as a sickle-free internal gear pump.

Alternatively, an in 5 illustrated gear arrangement 74 be used, which also has an inner rotor 100 and an outer rotor 102 includes, but for the separation of the suction side 148 and print side 150 a sickle 152 is provided. Such an internal gear pump 14 can also be referred to as sickle internal gear pump.

It is preferred if at least some of the components of the internal gear pump 14 primitive, in particular tool falling, can be produced. For example, the housing parts Kings nen 66 . 68 and 70 and / or the gears of the gear assembly 74 Be sintered parts. The outer housing 56 and / or the flange 58 are formed in an advantageous manner as a sheet metal part.

Individual features of the internal gear pump described above 14 can also be advantageous if it has its own drive / bearing shaft, so not with the help of a shaft 48 an internal combustion engine 12 is driven. These features relate in particular to the construction of the housing with the outer housing 56 and the housing parts 66 . 68 and 70 , the possibility of flow adjustment of the feed pump 18 , the integration of the entrance 26 and / or the output 28 and / or the pressure relief valve 88 in the housing part 70 as well as the configuration of the gear arrangement 74 ,

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 102006056844 A1 [0002]

Claims (10)

Internal gear pump ( 14 ) with at least one about a drive axis ( 104 ) rotatably driven inner rotor ( 100 ), characterized in that the inner rotor ( 100 ) by means of a in an internal combustion engine ( 12 ) storable or stored shaft ( 48 ), which one around the drive axle ( 104 ) of the inner rotor ( 100 ) rotatable shaft section ( 114 ) for driving the inner rotor ( 100 ) having. Internal gear pump ( 14 ) according to claim 1, characterized in that the shaft ( 48 ) a camshaft or a crankshaft or a balancer shaft of the internal combustion engine ( 12 ). Internal gear pump ( 14 ) according to claim 1 or 2, characterized in that the shaft section ( 114 ) by an axial direction of the shaft ( 48 ) seen free shaft end ( 54 ) formed with the inner rotor ( 100 ) is connectable or connected. Internal gear pump ( 14 ) according to claim 3, characterized in that the shaft end ( 54 ) in a central opening ( 106 ) of the inner rotor ( 100 ) is insertable or imported. Internal gear pump ( 14 ) according to one of the preceding claims, characterized in that a joining direction ( 128 . 130 ) for connecting the shaft ( 48 ) and the inner rotor ( 100 ) collinear with the drive axle ( 104 ) of the inner rotor ( 100 ) runs. Internal gear pump ( 14 ) according to one of the preceding claims, characterized in that it is designed as a sickle-internal gear pump. Internal gear pump ( 14 ) according to one of claims 1 to 5, characterized in that it is designed as a sickle-free internal gear pump. Internal gear pump ( 14 ) according to one of the preceding claims, characterized in that the inner rotor ( 100 ) eccentric to an outer rotor ( 102 ) is mounted and one with an internal toothing ( 134 ) of the outer rotor ( 102 ) meshing external toothing ( 136 ), and that the internal toothing ( 134 ) of the outer rotor ( 102 ) by on the outer rotor ( 102 ) rotatably mounted rollers ( 138 ) is formed. Internal combustion engine ( 12 ) with an internal gear pump ( 14 ) according to one of claims 1 to 8. Fuel injection system ( 10 ) for an internal combustion engine ( 12 ) comprising an internal gear pump ( 14 ) according to one of claims 1 to 8.