CN102648350A

CN102648350A - External Gear Pump

Info

Publication number: CN102648350A
Application number: CN2010800556614A
Authority: CN
Inventors: S·芙洛; H·西格尔; J·阿诺德
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2009-12-08
Filing date: 2010-10-11
Publication date: 2012-08-22
Anticipated expiration: 2030-10-11
Also published as: WO2011069713A2; WO2011069713A3; CN102648350B; DE102009047610A1; EP2510239A2

Abstract

An external gear pump (14) comprises two rotatable gear wheels (100, 102) that mesh with each other. According to the invention, at least one gear wheel (100) is mounted, in relation to the rotational axis (132) thereof, in the radial direction by the contact of tooth tips (162) directed radially outward with a mounting surface (136) located radially outward. The operating behavior and efficiency of the external gear pump (14) according to the invention are improved by optimized guidance of the liquid to be delivered both on the suction side and on the pressure side by means of openings (170, 174) and channels (172, 176).

Description

External gear pump

Technical field

The present invention relates to a kind of external gear pump according to claim 1 preamble.

Background technique

By the known a kind of external gear pump of DE 10 2,006 056 843A1, this external gear pump has two rotatable, pitch wheels.These gear supports are in housing.At the run duration of external gear pump at suction side draw fluid, on-load pressure and input on the pressure side.

By disclosed DE 10 2,008 054 751.4 known a kind of external gear pumps in the back, wherein pitch wheel is bearing in the housing ring through tooth top.This housing articulating is received between first housing member and second housing member, wherein, the axially directed of gear and/or supporting is carried out through first and second housing members.

When external gear pump is designed to the highest transmission power (this especially realizes through the facewidth of increase gear and the corresponding coupling of housing ring simply); Possibly when disadvantageous operating point, when the high rotating speed of external gear pump, cause in suction channel, forming bubble owing to restriction loss on the suction side at external gear pump, these bubbles are sucked in the tooth cavity and there then possibly cause undesirable cavitation effect.

Summary of the invention

Task of the present invention provides a kind of external gear pump, even if it especially has enough big flow cross section in suction side when big feed flow, makes in all operating points, not form or only in very little scope, form bubble.In addition, should make simply especially by external gear pump of the present invention and be durable.

The external gear pump of the characteristic of this task through having claim 1 solves.Favourable expanded configuration provides in the dependent claims.In addition, in the important characteristic specification below of the present invention and find in the accompanying drawings, wherein, these characteristics not only can individually and can be important for the present invention with different combinations, and this is not needed to spell out once more.

Be that suction areas and low-pressure channel hydraulically interconnect with a double big cross section of the mode with first approximation through what can realize by housing ring design proposal of the present invention.Obviously reduce the pressure loss on the suction side of external gear pump thus.Therefore even if in the external gear pump of gear with non-constant width and corresponding big transmission power, cavitation erosion do not occur yet.

Because by additional flow path of the present invention; I.e. perforation and at least one passage; Be arranged in the housing ring and this housing ring just in time the facewidth with gear is identical thick; So what be easy to realize is that when transmission power was big especially, the housing ring was provided with by perforation and the passage in the housing ring of the present invention all the time.Be that the facewidth of gear and the thickness of housing ring are same big.Therefore, in the housing ring, there are enough materials all the time, so that reserve by perforation of the present invention and passage.

Possible in addition is, the different modification with different transmission powers by external gear pump of the present invention are provided, and wherein, these different modification are being distinguished aspect the thickness of the width of gear and housing ring each other.In the modification of transmission power, additionally also in the housing ring, constitute by perforation of the present invention and passage with increase.

Reaching significant cost thus reduces; Because the gear pump with little transmission power and corresponding thin housing ring not perforation and passage also can be dealt with, and it is corresponding thicker and have by perforation of the present invention and passage to be used to have the housing ring of external gear pump of big transmission power.All other member can be used for this two pump modification.

Additional flow cross section is set up by the passage that the present invention reserves through perforation with on distolateral, and this perforation is with two distolateral interconnecting of housing ring, and passage will be bored a hole and is connected with the suction areas or the pressure span of external gear pump.This moulding is advantageous particularly especially therefore, because it has symmetrical structure, this is in flow characteristic and act on and play positive effect aspect the pressure on the gear.In addition, this moulding also is fit to through the sintering manufacturing very much, because perforation and passage also can be processed through the sintering mold of two-piece type easily.Also manufacturing expense is kept very low thus.

By in the housing ring of the present invention, between these two passages that on the housing ring is distolateral, extend, be provided with a dividing plate.Realized that thus housing is around the cornerite of gear and the supporting of gear in the housing ring can be through not reducing by passage of the present invention thus.Therefore, even if in gear pump, also obtain gear through the extraordinary supporting on the leaving a blank of the corresponding circle of its tooth top in the housing ring with big transmission power.

In the another kind of preferred design proposal by gear pump of the present invention, first housing member, second housing member and/or housing ring are welded to each other on excircle.Make these three described members fixing relative to each other thus.This means of fixation especially is particularly well adapted for producing in enormous quantities because they be can fine automation and on technology, move as safe as a housely.

In order to make the not outstanding outer diameter that surpasses housing member and/or housing ring of radially outward of weld seam, on housing member and/or housing ring, chamfering is set.In this chamfering, place weld seam.

Also realized other advantage thus, promptly weld beans can columniform outer surface attached to housing ring and housing member on, this can influence the manufacturing of the member that welds together and originally unfriendly by the assembling in the external casing of gear pump of the present invention.

The invention still further relates to a kind of fuel injection system with above-described external gear pump.Its design proposal and advantage are set forth in the above.At this point with reference to these elaborations.

Description of drawings

Set forth mode of execution of the present invention with reference to the accompanying drawings.Shown in the drawings:

Fig. 1 illustrates the schematic views with internal-combustion engine and fuel injection system of the external gear pump that is used for transfer the fuel;

Fig. 2 illustrates by the external gear pump of Fig. 1 view along the cutting line that in Fig. 3, marks with II-II;

Fig. 3 illustrates by the external gear pump of Fig. 1 view along the cutting line that in Fig. 2, marks with III-III;

Fig. 4 illustrates the zoomed-in view by the gearing of the external gear pump of Fig. 1; With

Fig. 5 illustrates the longitudinal section of passing housing ring 72 along the cutting line that in Fig. 3, marks with IV-IV;

Embodiment

In Fig. 1 generally with reference character 10 expression be used for provide the fuel injection system of fuel to comprise external gear pump 14 to internal-combustion engine 12.

Fuel injection system 10 has the storage vessel 16 that is used for fuel-in-storage.By means of preparatory transfer pump 18 fuel is transported to the low pressure line 22 from storage vessel 16, this preparatory transfer pump is preferably through adjustable drive unit, the especially drive unit driving of motor 20 forms.Through using the quantity delivered that adjustable drive unit that is used for preparatory transfer pump 18 can fuel metering ejecting system 10, thereby can reduce the conveyance loss that obtains through the fuel of carrying unnecessary amount, the fuel of this unnecessary amount must be transmitted back in the storage vessel 16 again.

For the fuel pressure that limits in the low pressure line 22 is provided with low voltage limit valve 24, when can predetermined pressure maximum being exceeded, fuel is transmitted back to the storage vessel 16 from low pressure line 22 through this low voltage limit valve.

Low pressure line 22 leads to the input end 26 of external gear pump 14.External gear pump loads high pressure to the fuel that is transfused to through input end 26.Be loaded the output terminal 28 arrival pressure ducts 30 of the fuel of high pressure through external gear pump 14, this pressure duct leads to the fuel collection device of rail 32 forms.This rail 32 provides the fuel that is loaded pressure for injection valve 34.These injection valves 34 are configured to a firing chamber in the firing chamber of internal-combustion engine 12 respectively and can realize that direct fuel injection is in the firing chamber.

Pressure in the rail 32 detects by means of pressure transducer 36.Can flow to control gear 40 by means of data circuit 38 with detected pressure correspondent voltage signal.This control gear 40 is connected with motor 20 through control wiring 42.

The internal-combustion engine housing 44 that internal-combustion engine 12 is illustrated with comprising a section, for example the internal-combustion engine housing of cylinder cap form.This internal-combustion engine housing 44 has a surface of shell 46 that outwards points to.In addition, this internal-combustion engine 12 comprises an axle, the especially axle of camshaft form, and this centers on the live axle 48 that axis 50 is rotatably supported on the internal-combustion engine housing 44 and is formed for external gear pump 14.Conversion ground, live axle 48 can constitute through the axle that separates with internal-combustion engine 12.

In internal-combustion engine housing 44, be provided with a housing opening 52, this housing opening driven shaft 48 passes, and makes shaft end 54 exceed in the surrounding environment that surface of shell 46 extends to internal-combustion engine 12.

External gear pump 14 has the external casing 56 of jar shape, and this external casing especially is connected with internal-combustion engine housing 44 by means of the flange 58 in the welding, for example through being threaded.External casing 56 has a case protrusion 60 of extending towards the direction of internal-combustion engine 12, and this case protrusion is inserted in the housing opening 52 of internal-combustion engine 12.Case protrusion 60 has a rounded housing of cross section and leaves a blank 62, and this housing is left a blank and can be supplied live axle 48 to pass.

The external casing 56 of external gear pump 14 seals with the seal arrangement 64 of internal-combustion engine housing 44 by means of annular each other.

Externally be provided with a plurality of housing members in the housing 56, promptly first housing member 66, with isolated second housing member 68 of first housing member and as the 3rd housing member 70 of housing lid.The 3rd housing member 70 and external casing 56 welding.Preferably, these

housing members

66,68 and 70 have the plane that is parallel to each other, and make these housing members form the sealing surface of metal with these planes.At this, can produce sealing force by means of the 3rd housing member 70, sealing power is pressed into

housing member

66 and 68 in the external casing 56.

Between first housing member 66 and second housing member 68, a housing ring 72 is set in the axial direction, in this housing ring, gearing 74 is set.This gearing 74 forms the real supply unit of external gear pump 14.This gearing 74 is bearing between first housing member 66 and second housing member 68 in the axial direction.Housing ring 72 is used for supporting gear device 74 radially.

For make

housing member

66 and 68 and housing ring 72 relative to each other locate, they are welded to each other through weld seam 168 (see figure 2)s.Weld seam 168 needs not to be liquid seal; Weld seam also can interrupt.Weld seam 168 is divided into two about segmental arcs of 100 ° in Fig. 3.Weld seam 168 preferably is arranged on the place that housing ring 72 has big material thickness.For weld seam 168 is not stretched out above

housing member

66 and 68 and housing ring 72 diametrically, on these members, construct chamfered edge (not being with reference character), weld seam 168 is arranged in these chamfered edges.

External gear pump 14 has a low-pressure channel 76 that is connected with input end 26 in low voltage side, and this low-pressure channel is configured in the 3rd housing member 70.Low-pressure channel 76 leads to suction kidney shape hole 78 (see figure 1)s, and this suction kidney shape hole is configured in second housing member 68.First housing member 66 is provided with a shape with suction kidney shape hole 78 and matches kidney shape hole 80 (see figure 2)s accordingly.

External gear pump 14 comprises a high-pressure channel 82 that is connected with output terminal 28 on the pressure side, and this high-pressure channel is configured in the 3rd housing member 70.High-pressure channel 82 is connected with pressure kidney shape hole 84, and this pressure kidney shape hole is configured in second housing member 68.Shape with pressure kidney shape hole 84 is set in first housing member 66 matches kidney shape hole 86 accordingly.By means of what pairing kidney shape hole 80 and 86 can be realized be, from both sides equably to gearing 74 on-load pressures.

In addition, external gear pump 14 comprises pressure limit valve 88 (referring to Fig. 2), and the fluid that when can predetermined operating pressure being exceeded, can set up between high-pressure channel 82 and the low-pressure channel 76 by this pressure limit valve connects.Pressure limit valve 88 is arranged in the connecting passage 90, and this connecting passage extends between high-pressure channel 82 and low-pressure channel 76.Pressure limit valve 88 has the valve body 94 and the valve spring 96 that are pressed into valve seat 92 in the connecting passage 90, one and these valve seat 92 mating reactions, and this valve spring is pressed onto valve body 94 on the valve seat 92.Connecting passage 90 seals by means of bulged-in plug 98 with the form formation of blind hole and on the open end of this connecting passage.

Input end 26 and output terminal 28 and pressure limit valve 88 are integrated in the 3rd housing member 70, can eliminate additional seal element to a great extent and can further reduce the number of components of external gear pump 14 thus.

Gearing 74 comprises first gear 100, this first gear and 102 engagements of second gear.First gear 100 has the diameter littler than second gear 102.First gear 100 is driven (referring to Fig. 2 and 3) by second gear 102.

Second gear 102 can be around spin axis 104 rotations (referring to Fig. 4) that set to this gear.This spin axis 104 at least approximately and axis 50 conllinear of live axle 48.

Second gear 102 has central opening 106, and the shaft end 54 of live axle 48 is inserted in this central opening.Live axle 48 has primary section 108, and this primary section is extended in the inside of internal-combustion engine housing 44.On primary section 108, connect the axle guide surface 112 of an axle stepped part 110, an especially spherical shaping, an axle section 114 and an axle bolt 116 that is provided with towards the direction of external gear pump 14 distolaterally.

Axle stepped part 110 is passed the housing of external casing 56 and is left a blank 62.In order to make live axle 48 with respect to external gear pump 14 sealings, a seal arrangement 118 is set, the sealing device especially constitutes with the form of radial seal ring.The sealing device is arranged on case protrusion 60 inside and comprises first sealing lip 120 that only schematically illustrates, and stops from internal-combustion engine 12 inner oil through this first sealing lip to enter into external gear pump 14.In addition, seal arrangement 118 comprises second sealing lip 122, stops from external gear pump 14 inner fuel through this second sealing lip to be discharged in the inner room of internal-combustion engine 12.

Axle guide surface 112 is bearing in the columniform supporting surface 124, and this supporting surface is formed on first housing member 66.On supporting surface 124, connect a centering face 126 that tilts with respect to supporting surface 124, can more easily axle guide surface 112 be incorporated in the supporting surface 124 through this centering face.

Axle section 114 for example has polygonal profile, especially hexagonal profile.The hexagonal profile mating reaction of the central opening 106 of this profile and second gear 102.Opening 106 makes second gear 102 be connected with live axle 48 with a gap diametrically less times greater than the profile of axle section 114.

For live axle 48 is engaged with external gear pump 14, live axle 48 and external gear pump 14 on 128 and 130 direction of engagement represented towards moving each other.The spin axis 104 of the direction of engagement 128 and 130 and second gear 102 and axis 50 conllinear of live axle 48.

Axle bolt 116 preferable configuration are columniform and during being incorporated into shaft end 54 in the external gear pump 14, are used as other insertion auxiliary device.In the simplest situation, external gear pump 14 is set to freely on the shaft end 54.Between the joint aging time of the live axle 48 and second gear 102, stop the damage of seal arrangement 118 in the following manner; Promptly an axle bolt 116 at first is coupled in the central opening 106 of second gear 102, and axle stepped part 110 is inserted into housing and leaves a blank in 62 and the cooperating of formation and sealing

lip

120 and 122 then.

First gear 100 can be around spin axis 132 rotations.The spin axis 132 of first gear 100 and the spin axis 104 of second gear 102 are band gaps with respect to the position of the plane of rotation of gear.Gear 100,102 is through their the intermeshing cooperation in mesh regional 134 and through being supported with the contacting of supporting surface that sets to one of these gears 100,102 diametrically.

First gear 100 is bearing in a section ground and is on first supporting surface 136 of cylinder side face shape.This first supporting surface 136 for example about 70 ° extend to about 90 ° segmental arc 138.First supporting surface 136 carries out the transition in the first housing face 140 that a same section ground is cylinder side face shape.

Be provided with second supporting surface 142 that a section ground is cylinder side face shape in order to support second gear 102, this second supporting surface for example about 30 ° extend to about 50 ° segmental arc 144.Second supporting surface 142 carries out the transition in the second housing face 146 that a same section ground is cylinder side face shape.

Supporting

surface

136 and 142 and

housing face

140 and 146 surround gear 100,102.Gear 100,102 has the diameter that obviously differs from one another, and makes that thus said cornerite is big especially.

Supporting

surface

136 and 142 and mesh regional 134 between them, limit a suction areas 148, can give external gear pump 14 inputs medium to be carried through this suction areas.Mesh regional 134 with a transition part between

housing face

140 and 146 in the pressure span 150 that on the pressure side limits external gear pump 14.

External gear pump 14 comprises first force generating apparatus 152, and this force generating apparatus especially constitutes with the form of pressure chamber 154.Pressure chamber 154 has the chamfering geometrical shape, referring to Fig. 2.This pressure chamber 154 extends around first gear 100 with the first housing face 140.

External gear pump 14 also comprises second force generating apparatus 156 of second pressure chamber, 158 forms.This pressure chamber also has the chamfered edge geometrical shape and extends around second gear 102 with the second housing face 146.

Plane of rotation with gear 100,102 is reference, and

pressure chamber

154 and 158 is arranged on the both sides of gear 100,102 respectively doublely, makes gear 100,102 be loaded identical pressure in the axial direction from both sides.

Gear 100,102 has a plurality of teeth 160 respectively.These teeth 160 have the Topland of outside sensing, and these Toplands are according to the curvature bending of the supporting surface that matches 136,142.

At the run duration of external gear pump 14, give this external gear pump input fluid to be carried through input end 26.On driving direction 164, drive second gear 102 by means of live axle 48.Can be from the suction areas 148s along supporting

surface

142 and 136 and input to pressure span 150 with this mode along the fluid that

housing face

140 and 146 will be to be carried.

Force generating apparatus

152 and 156 by means of

pressure chamber

154 and 158 forms produces power through the fluid to be carried that is loaded pressure, and this power is pressed onto gear 100,102 on the supporting surface 136,142 that sets to this gear.Thus, the Topland 162 of the radially outward of gear 100,102 sensing forms respectively with the sealing of the supporting surface that matches 136,142 and contacts.Can realize that with this mode gear 100,102 is only being supported and realizing simultaneously that good seal action is to open suction areas 148 and pressure span in 150 minutes in the radial direction on the supporting surface and in mesh regional 134.

In the elongation line of high-pressure channel 82 and/or low-pressure channel 76, in housing ring 72, constitute a perforation 170,174 respectively by the present invention.To bore a hole and 170 be connected with the tooth cavity hydraulic pressure of gearing 74 through being configured in passage 172,176 in the housing ring 72 equally with 174.Not only in the suction areas 148 of gearing 74 but also in pressure span 150, increase flow cross section thus, this pro influences the roadability and the efficient of gear pump.

Between

passage

172 and 176, remain with a dividing plate 178 (referring to Fig. 5), make the cornerite of the gear 100,102 that on top circle, is supported keep size constant.

Claims

1. external gear pump (14); It has two rotatable, pitch wheels (100,102), wherein; These gears (100; 102) be arranged in the housing ring (72), it is characterized in that, in said housing ring (72), constitute the hydraulic pressure between low-pressure channel (76) and suction areas (148) and connect.

2. external gear pump (14); It has two rotatable, pitch wheels (100,102), wherein; These gears (100; 102) be arranged in the housing ring (72), it is characterized in that, in said housing ring (72), constitute the hydraulic pressure between high-pressure channel (76) and pressure span (150) and connect.

3. according to the external gear pump (14) of claim 1 or 2; It is characterized in that; In said housing ring (72), there is first perforation (170); Said first perforation (170) is arranged on the elongation line of said low-pressure channel (76), and said first perforation (170) is connected with said suction areas (148) through at least one first passage (172).

4. according to the external gear pump (14) of claim 2 or 3; It is characterized in that; In said housing ring (72), there is second perforation (174); Said second perforation (174) is arranged on the elongation line of pressure channel (150), and said second perforation (174) is connected with said pressure span (150) through at least one second channel (176).

5. according to the external gear pump (14) of claim 2 or 3, it is characterized in that, in said housing ring (72), between two first passages (172) and/or two second channels (176), have a dividing plate (178).

6. according to the external gear pump (14) of one of above claim; It is characterized in that; Said housing ring (72) is arranged between first housing member (66) and second housing member (68), and said housing ring (72) is fixing through being welded to connect (168) with respect to said first housing member (66) and/or said second housing member (68).

7. according to the external gear pump (14) of one of above claim, it is characterized in that said housing ring (72), said first housing member (66) and/or said second housing member (68) are through sintering, especially processed by welding agglomerated material.

8. the fuel injection system (10) that has external gear pump (14) according to one of above claim.