CN1975171A - Pump - Google Patents

Abstract

The pump ( 10, 110, 210 ) may comprise a casing ( 39, 139, 239 ) and a substantially disk-shaped impeller ( 36, 136, 236 ) that rotates within the casing. A group of depression-shaped grooves may be formed on at least one of the front and reverse surfaces of the impeller and the two casing internal surfaces in opposition to these surfaces. The depression-shaped grooves may extend from the center towards the outer periphery of the impeller. When the impeller rotates, fuel within the clearance between the impeller and the casing is propelled, within the depression-shaped grooves, from the center towards the periphery. In this way, forces are generated in the direction that increases the clearance between the impeller and the casing. It is preferred that the group of depression-shaped grooves 38 b is formed closely spaced near the discharge hole 50 (area B), and elsewhere (area C) is formed more widely spaced. Also, it is preferred that the clearance between the surface on which the depression-shaped grooves 136 c are formed and the surface 138 b in opposition thereto increases from the center of the impeller towards the outer periphery of the impeller.

Description

Pump

The cross reference of related application

The preference of the application requires Japanese patent application 2005-341956 number, 2006-002734 number and 2006-126268 number, its full content are incorporated into the application with as a reference.

Technical field

The present invention relates to a kind of being used to sucks such as the fluid of fuel etc., the pump that increases its pressure and discharge this pressurized fuel.

Background technique

Such pump generally includes to be similar to and is discoidal impeller and holds this impeller so that the rotatable pump case of this impeller.Obverse and reverse at this impeller all forms sets of recesses.The a plurality of recesses that form each sets of recesses are in the circumferencial direction repeated arrangement.Extend to the circular groove of downstream from upstream extremity, be formed on the zone relative on two pump case internal surfaces with the sets of recesses on this impeller.Form the pump stream by sets of recesses on the impeller and the circular groove on the pump case.Inlet is formed on this pump case.This inlet connects the upstream extremity of this pump stream and the outside of pump case.Outlet is formed on this pump case.This outlet connects the downstream of this pump stream and the outside of pump case.When impeller rotated in pump case inside, fluid was inhaled in the pump stream from inlet.The fluid that is inhaled in the pump stream is pressurized in the downstream that flows to the pump stream.The fluid of pressurization is discharged to the pump case outside from outlet.

In this pump, the pressure that acts on the impeller obverse and reverse is tending towards inhomogeneous.In addition, the pressure reduction that acts on the impeller obverse and reverse is tending towards inhomogeneous according to the position on the circumferencial direction.For example, the pump stream of fluid in inlet is inhaled into pump case, and pressurized in this pump stream, and from the outlet discharge.At the upstream extremity of the pump stream that is connected with inlet, fuel is inhaled into from a surface of impeller, but fuel is not inhaled into from another surface.In addition, in the downstream of the pump stream that is connected to outlet, fuel is discharged from a surface of impeller, but fuel is not discharged from another surface of impeller.As a result, near entrance and exit, the pressure reduction that acts on the obverse and reverse of impeller becomes bigger.Change according to the position on the circumferencial direction if act on the pressure reduction of impeller, then impeller will tilt with respect to impeller shaft, and can produce the contact between impeller and the pump case.If impeller continues rotation under this condition, pump performance will reduce owing to frictional loss and wearing and tearing.

Therefore, in the disclosed pump, the sagging connected in star of U-shaped is formed at the obverse and reverse of impeller in Japanese kokai publication hei 6-280776 patent gazette.In this pump, when impeller rotated, fluid flowed in these sagging connected in stars.When the fluid in flowing into this sagging connected in star is discharged from the sagging connected in star from this, with produce along impeller shaft to velocity component.Therefore, the fluid of discharging from the connected in star that sink is exerted pressure to the pump case internal surface vertically.Like this, with the power that produces effect in the direction increasing the gap between impeller and the pump case internal surface, thereby prevent the contact between impeller and the pump case, and improve the efficient of pump.Yet, only be difficult to prevent the inclination of impeller, and can not prevent the contact between impeller and the pump case fully by in impeller, forming the connected in star that sink.

Summary of the invention

Therefore, the purpose of this invention is to provide a kind of pump that can effectively suppress the contact between impeller and the pump case.

According to a scheme of the present invention, this pump comprises: pump case, and in this pump case, rotate, be approximately discoidal impeller, wherein, obverse and reverse at this impeller all forms sets of recesses, forms the circumferencial direction repeated arrangement of a plurality of recesses of each sets of recesses along impeller; With the positive first relative pump case internal surface of this impeller on be formed with first groove, this first groove with the described sets of recesses of this impeller in one group of zone of facing in extend to downstream from upstream extremity; On the second pump case internal surface relative, be formed with second groove with this impeller reverse side, this second groove with the described sets of recesses of this impeller in the zone faced of another group in extend to downstream from upstream extremity; On this pump case, form entrance and exit, this inlet makes one upstream extremity in this first groove and second groove be connected with pump case is outside, outlet makes another the downstream in this first groove and second groove be connected with the pump case outside, therefore, when this impeller rotation, fluid is inhaled into pump case from inlet, and this fluid that is sucked into pump case is pressurizeed by impeller, and is discharged to the pump case outside from outlet.

According to a scheme of the present invention, at least on the first pump case internal surface and the second pump case internal surface, be formed with the connected in star group of sinking, described sagging connected in star encloses extension outwardly from the center, and along impeller sense of rotation skew, described sagging connected in star group asymmetricly forms according to the position of this first groove and this second groove running shaft with respect to this impeller.

In this pump, when impeller rotated, the fluid in the gap between impeller and the pump case was inhaled in this sagging connected in star group, and enclosed propelling outwardly from the center.The direction of the centrifugal force of the fluid in this direction and the gap that acts between this impeller and the pump case is identical.Therefore when impeller rotates, will sink fluid in the connected in star group of generation is effectively enclosed the power of propelling outwardly from the center.Exert pressure in this fluid pair pump case surface relative with impeller of enclosing propelling outwardly from the center in the connected in star group of sinking, and impeller is produced effective lift (that is, along the power that increases the directive effect in gap between this impeller and the pump case internal surface).

In addition, according to being formed at first groove on the pump case internal surface and the position of second groove, asymmetricly form the connected in star group of to sink.By asymmetricly forming the connected in star group of sinking, can change the size that acts on the lift on this impeller according to the zone on the impeller.Asymmetricly form this sagging connected in star group by position, can increase the lift that acts on this impeller in the big zone of pressure reduction, and can reduce to act on the lift on this impeller in the little zone of pressure reduction according to this first groove and second groove.Like this, can eliminate the inhomogeneous of pressure reduction between this impeller obverse and reverse.Can suppress the inclination of impeller, and suppress the contact between this impeller and the pump case with respect to impeller shaft.

Can realize asymmetricly forming this sagging connected in star group by the following method, for example, form the zone of compact arranged zone of groove and the sparse arrangement of groove or form the long zone of groove length and zone that groove length is short or form the dark zone of depth of groove and zone that depth of groove is shallow or form the wide zone of recess width and zone that recess width is narrow or form reeded zone and unnotched zone.

In said pump, preferably, on the pump case internal surface near the zone of outlet and/or on the pump case internal surface in the zone near inlet, act on lift on this impeller greater than the lift in other zones by what described sagging connected in star group produced.

Fluid is inhaled into pump case from inlet, and is pressurized in pump case, and discharges from outlet.Therefore, near entrance and exit, the pressure reduction that acts on the impeller obverse and reverse is tending towards bigger.The connected in star group forms the lift that makes near the effect impeller of generation inlet and/or the outlet greater than other zones if sink, and then can eliminate the pressure reduction with regional change effectively.

Alternatively, be positioned at the connected in star group of to sink on the impeller, that produce lift and can only be formed near zone of this outlet and/or near the zone this inlet.According to this structure, lift only acts on this impeller near the zone this outlet and/or near the zone this inlet, so can eliminate this pressure reduction with regional change effectively.

Preferably, each the sagging connected in star that constitutes this sagging connected in star group from the center of this impeller towards the periphery with spiral extension.By forming the spiral helicine groove that encloses from the center outwardly, can swimmingly fluid be sucked this groove.

According to another aspect of the present invention, on at least one surface among reverse side, this first pump case internal surface and the second pump case internal surface of the front of this impeller, this impeller, be formed with sagging connected in star, so that when impeller rotates, fluid in the gap between this impeller and pump case is pressurized, and produces power along the direction that increases gap between this impeller and the pump case.In addition, when the not run-off the straight of the relative pump case of impeller, periphery towards this impeller increases from the center of this impeller to be formed with the face of the connected in star that sink and the gap between the face relative with it.

In this pump, be formed with the face of the connected in star that sink and the gap between the face relative and increase towards the periphery of this impeller with it.Therefore, even this impeller slight inclination can not contact between the periphery of this impeller and the pump case internal surface yet.On the other hand, at the center of this impeller, the face and the gap between the face relative with it that are formed with the connected in star that sink are little.This gap is more little, and the lift (that is, the edge increases the power of the directive effect in the gap between this impeller and the pump case) that is produced by the fluid in this sagging connected in star is big more.Therefore, can increase the lift that produces by the fluid in this sagging connected in star.Like this, the bigger inclination of this impeller can be prevented, and contacting of this impeller and pump case can be suppressed.

In this pump, preferably, be formed with the face of the connected in star that sink and a face in the face relative and form flat surfaces, and another face forms taper, thereby make gap peripheral increase of this another side and this impeller from this impeller center towards impeller with it.According to this structure, one that is formed with in the face of the connected in star that sink and the face relative with this face forms flat surfaces, therefore makes that the processing on this plane is simple.

Preferably, this sagging connected in star from the impeller center towards the periphery with spiral extension.In addition, this sagging connected in star can be formed on this impeller or on this pump case.

According to another aspect of the present invention, entrance and exit all is formed on this pump case, and inlet makes the upstream extremity of the pump stream that formed by this sets of recesses, first groove and second groove be connected with the pump case outside.Outlet makes the downstream of this pump stream be connected with pump case is outside.Be formed on the inlet side impeller surface with the sagging connected in star of pump stream sealing and inlet side pump case internal surface at least one surface on, neither be formed on the outlet side impeller surface with the connected in star that should sink of pump stream sealing, also be not formed on the outlet side pump case internal surface.

In such pump, because the power that the pressure reduction of the fluid in the pump stream causes is along the directive effect of this impeller being pressed to inlet side pump case internal surface.In other words, it is pressurized when the upstream side (that is inlet side) from the pump stream flows to downstream side (that is outlet side) to be inhaled into the fluid of pump stream.Therefore, the fluid in the pump stream is higher than the pressure of inlet side at the pressure of outlet side.Therefore, the pressure that bear on the surface of the outlet side of this impeller is higher than the pressure that bear on the surface of inlet side, so this impeller is subjected to along the power of inlet side pump case internal surface direction.

In this pump, sagging connected in star is not formed on the outlet side impeller surface, is not formed on the outlet side pump case internal surface yet.Therefore, on this outlet side impeller surface, do not produce lift; Lift only results from this inlet side impeller surface.Lift on the inlet side impeller surface is along the directive effect (that is, along the directive effect of impeller being pressed to inlet side pump case internal surface) of offsetting the power that is produced by pump case inner fluid pressure reduction.Can suppress impeller pressed to and contact this inlet side pump case internal surface like this.

In this pump, preferably, on this outlet side pump case internal surface, be formed with circumferencial direction protuberance circlewise along this impeller.If protuberance is formed on the outlet side pump case internal surface, even there is contact between this outlet side pump case internal surface and impeller, this outlet side pump case internal surface contacts with impeller is only local.Therefore, can reduce frictional loss when impeller contacts with pump case.

In addition, preferably, this protuberance is located at pump stream inside.By this protuberance being located at pump stream inside, can suppressing this protuberance of process and flow into the fluid that from the pump stream, leaks in the gap of outlet side.Like this, can be in pump case effectively convection cell pressurize, and can improve this pump performance.

In addition, this pump also comprises the motor room that is arranged at this pump case outside and is contained in motor in this motor room that wherein this motor has rotatable axle.In this case, preferably, the outlet that the pump stream is connected with the motor room and be formed in the pump case by the through hole that machine shaft passes, and the other end of this machine shaft is installed to this impeller.

According to this structure, because high-pressure liquid is back to pump case through the gap between rotating shaft and the through hole from the motor room, this impeller is subjected to along the power of the direction of inlet side pump case internal surface.As a result, can suppress contact between this impeller and the outlet side pump case internal surface.In addition, even this impeller is subjected to along the power of inlet side pump case internal surface direction, the lift that is produced by this sagging connected in star is along the directive effect of this power of counteracting, the contact between this impeller and the inlet side pump case internal surface of therefore can drawing up.

According to another scheme of the present invention, entrance and exit is formed on this pump case, this inlet makes the upstream extremity of the pump stream that formed by this sets of recesses, first groove and second groove be connected with the outside of this pump case, and this outlet is connected the downstream of this pump stream with the outside of this pump case; This inlet side connected in star that sink is formed at least one surface in inlet side impeller surface and this inlet side pump case internal surface, so that fluid is pressurized and produce lift when the rotation of this impeller, this lift is along the directive effect that increases the gap between this inlet side impeller surface and the inlet side pump case internal surface; This outlet side connected in star that sink is formed at least one surface in this outlet side impeller surface and this outlet side pump case internal surface, so that fluid is pressurized and produce lift when the rotation of this impeller, this lift is along the directive effect that increases the gap between this outlet side impeller surface and the outlet side pump case internal surface; According to number and/or shape that the number and/or the shape of the sagging connected in star of this inlet side are determined the sagging connected in star of this outlet side, the lift that connected in star produces so that this outlet side sink is less than the lift of the sagging connected in star generation of this inlet side.

According to this pump, can also suppress this inlet side pump case internal surface is pressed to and contacted to this impeller.

These schemes and feature can be used alone or in combination to make improved pump.In addition, reading following detailed description and in conjunction with the accompanying drawings and claim, other purposes of the present invention, feature and advantage will be easy to understand.Certainly, supplementary features disclosed herein and aspect can be used separately or with above-mentioned aspect and characteristics combination.

Description of drawings

Fig. 1 is the vertical cross section according to the pump of first representative embodiment of the present invention;

Fig. 2 is for to cut open the sectional drawing of getting along the II-II line among Fig. 1;

Fig. 3 is for to cut open the sectional drawing of getting along the III-III line among Fig. 1;

Fig. 4 for according to the pump of second representative embodiment of the present invention corresponding to cut open the sectional drawing of getting along the II-II line among Fig. 1;

Fig. 5 for according to the pump of second representative embodiment of the present invention corresponding to cut open the sectional drawing of getting along the III-III line among Fig. 1;

Fig. 6 is for explaining the schematic representation of the example that is formed at the sagging connected in star on the pump case;

Fig. 7 is for explaining the schematic representation of another example that is formed at the sagging connected in star on the pump case;

Fig. 8 is for to cut open the sectional drawing of getting along the VIII-VIII line among Fig. 7;

Fig. 9 is for to cut open the sectional drawing of getting along the IX-IX line among Fig. 7;

Figure 10 is the vertical cross section according to third generation table embodiment's of the present invention pump;

Figure 11 is impeller (the outlet side surface) planimetric map of the pump shown in Figure 10;

Figure 12 is for explaining the view of the shape that is formed at the groove in the impeller outlet side surface shown in Figure 11;

Figure 13 is the sectional drawing according to the amplification of third generation table embodiment's pump;

Figure 14 is the vertical cross section according to the pump of the 4th representative embodiment of the present invention;

Figure 15 is the planimetric map from the impeller of the 4th representative embodiment of bottom observation;

Figure 16 is for explaining the schematic representation of the shape that is formed at the groove in the impeller bottom surface shown in Figure 15;

Figure 17 is the sectional drawing of the amplification of the pump of the 4th representative embodiment according to the present invention;

Figure 18 is the sectional drawing that the amplification of the pump of the 5th representative embodiment according to the present invention is shown;

Figure 19 is the planimetric map from the impeller of the 5th representative embodiment of bottom observation;

Figure 20 is the planimetric map that another example that is formed at the sagging connected in star on the impeller top surface is shown;

Figure 21 is the planimetric map that another example that is formed at the sagging connected in star on the impeller top surface is shown;

Figure 22 is the planimetric map that another example that is formed at the sagging connected in star on the impeller top surface is shown; And

Figure 23 shows the sink direction of connected in star and the schematic relation between the internal combustion direction of flow of gap.

Embodiment

First representative embodiment

Below with reference to the Wesco pump (Wesco pump) 10 of accompanying drawing explanation according to the first embodiment of the present invention.Wesco pump 10 is for being used for the petrolift of Motor Vehicle.Wesco pump 10 can be used in the fuel tank, and supplies fuel to motor vehicle engine.

As shown in Figure 1, Wesco pump 10 comprises electric motor units 12 and pump unit 14.Electric motor units 12 has rotor 18.Rotor 18 comprises rotating shaft 20, is fixed to the laminated iron core 22 in the rotating shaft 20, the commutator 24 that is wrapped in the coil (this is not shown) on the laminated iron core 22 and is connected to end turn.Rotating shaft 20 is supported by housing 16 by bearing 26,28.Permanent magnet 30 is fixed to the inside of housing 16 to center on rotor 18.Not shown terminal is located on the top cover 32 that is connected with the top of housing 16, thereby to electric motor units 12 power supplies.Coil is activated by brush 34 and commutator 24, thus rotor 18 and rotating shaft 20.

The bottom of housing 16 holds pump unit 14.This pump unit 14 comprises and is approximately discoidal impeller 36.Periphery, end face upper edge at impeller 36 has formed sets of recesses 36a.Periphery, upper edge, bottom surface at impeller 36 has formed sets of recesses 36b.Through hole is formed at the center of impeller 36, and it is connected to rotating shaft 20 to prevent relative rotation.

The pump case 39 that holds impeller 36 comprises the pump cover 38 and the pump housing 40.

As shown in Figure 2, formation groove 38a in relative with the sets of recesses 36a zone on pump cover 38.Groove 38a forms approximate C shape, and 36 sense of rotation is stretched over downstream from upstream extremity along impeller.Outlet 50 is formed on the pump cover 38, and extends to the end face of pump cover 38 from the downstream of groove 38a always.Outlet 50 connects the inside of pump case 39 with outside (that is the inner space of electric motor units 12).Form the first pump stream 44 by sets of recesses 36a and groove 38a.Sink connected in star group 38b, 38b... is located on the bottom surface of pump cover 38 and radially concentrates.This group sagging connected in star 38b, 38b... will be described hereinafter.

As shown in Figure 3, formation groove 40a in relative with the sets of recesses 36b zone on the pump housing 40.38a is similar to groove, and groove 40a forms approximate C shape, and 36 sense of rotation is stretched over downstream from upstream extremity along impeller.Inlet 42 is formed in the pump housing 40, and extends to the upstream extremity of groove 40a from the bottom surface of the pump housing 40 always.Inlet 42 connects the inside of pump case 39 with outside (that is the outside of Wesco pump 10).Form the second pump stream 46 by sets of recesses 36b and groove 40a.Sink connected in star group 40b, 40b... is located on the end face of the pump housing 40 and radially concentrates.This sink connected in star group 40b, 40b... will be described hereinafter.

When impeller 36 rotated in pump case 39, fuel 42 was inhaled into the pump unit 14 and is directed in the pump stream 44,46 from entering the mouth.Fuel is pressurized when fuel flow path 44,46 flows, and is pushed into towards electric motor units 12 from exporting 50.Passed through electric motor units 12 by the fuel that advances towards electric motor units 12, and be discharged to the external world from the exhaust port 48 that is formed on the top cover 32.

As shown in Figure 2, sagging connected in star group 38b, the 38b... that is formed on the pump cover 38 is of similar shape and size.Sink connected in star 38b from extending towards the periphery with curve-like (helical) near the center.Near the end of peripheral sagging connected in star 38b with respect to being offset near the end at center sense of rotation (in the direction of arrow A) along impeller 36.

Interval between the adjacent sagging connected in star 38b changes according to the formation zone of this groove.Compare with sagging connected in star 38b, 38b... in the zone C that is formed at the area B outside, sagging connected in star 38b, the 38b... (upstream extremity to groove 38a is extended in an end of area B) that are formed in the area B that exports 50 next doors are more tight at the center.Be provided with distance D between the peripheral end portion of sagging connected in star 38b and the internal edge of groove 38a.In other words, width is the plane annular of D, is formed between the internal edge of the peripheral end portion of sink connected in star 38b, 38b... and groove 38a.By this plane sealing sagging connected in star 38b, 38b... and groove 38a.

As shown in Figure 3, sagging connected in star group 40b, the 40b... that is formed on the pump housing 40 is of similar shape and size.Sink connected in star 40b from extending towards the periphery with curve-like (helical) near the center.The end of sagging connected in star 40b peripheral near is offset with respect near the direction (in the direction of arrow E) of the end the center along impeller 36 rotations.

Interval between the adjacent sagging connected in star 40b changes according to the formation zone of this groove.Compare with sagging connected in star 40b, 40b... in the regional G that is formed at regional F outside, sagging connected in star 40b, the 40b... (extend to inlet 42 end of regional F) that are formed in the regional F on downstream end next door of groove 40a are more tight at the center.Be provided with distance H between the peripheral end portion of sagging connected in star 40b and the internal edge of groove 40a.In other words, width is that the plane annular of H is formed between the internal edge of the peripheral end portion of sink connected in star 40b, 40b... and groove 40a.

In the Wesco pump 10 according to present embodiment, connected in star group 38b, 38b sink ... be formed at respectively in the pump cover 38 and the pump housing 40 with sagging connected in star group 40b, 40b....When impeller 36 rotations, the fuel in the gap between impeller 36 and the pump case 39 is inhaled among sink connected in star group 38b, 38b... and sagging connected in star group 40b, the 40b....The outer end of sagging connected in star 38b, 40b is offset with respect to the sense of rotation of inner end along impeller 36.Therefore, when impeller 36 rotations, the direction that fuel is sucked the viscous force among sink connected in star 38b, the 40b is to point to peripheral from the center of impeller 36.The direction that acts on the centrifugal force on the fuel in the gap between impeller 36 and the pump case 39 during 36 rotations of this direction and impeller is identical.Therefore, will produce power when impeller 36 rotations, the direction that enclose outward from the center on this power edge advances the fuel sink connected in star 38b, the 40b effectively.The fuel that encloses propelling outwardly from the center among sagging connected in star group 38b, 38b... and sagging connected in star group 40b, the 40b... pushes impeller 36 simultaneously from end face and bottom surface, so impeller 36 maintains between the pump cover 38 and the pump housing 40.

In addition, in pump cover 38, sink connected in star group 38b, 38b... near outlet 50 (area B) closely arrange, and sink connected in star group 38b, 38b... are in the sparse arrangement in other positions (zone C).In the pump housing 40, sink connected in star group 40b, 40b... near the downstream of groove 40a (regional F) closely arrange, and connected in star group 40b, 40b... (regional G) the sparse arrangement in other positions of sinking.At compact arranged area B of groove and F, more fuel is advanced to the periphery from the center, and therefore the power that acts on the impeller 36 is bigger, and the end face of impeller 36 and the pressure reduction on the bottom surface are cancelled.Like this, can suppress the inclination of impeller 36, and the contact between impeller 36 and the pump case 39 can be inhibited with respect to axle.In addition, at the zone C and the G of the sparse arrangement of groove, because therefore big flat surfaces can keep sealing.Therefore, the inclination of the impeller 36 of can drawing up, and can reduce the fuel leak that comes the self-pumping stream.

Like this, the Wesco pump 10 according to present embodiment can reduce frictional loss and wearing and tearing, and can reduce the fuel leak in the pump stream.Therefore, can effectively improve pump performance.

Second representative embodiment

Below be explained with reference to the drawings Wesco pump according to second embodiment.Be similar to Wesco pump 10 according to the structure of second embodiment's Wesco pump according to first embodiment, with first embodiment's difference only for being formed at the structure of the sagging connected in star group on the pump case.Here only explain the difference between second embodiment and first embodiment, omit explanation its common ground.

As shown in Figure 4, sagging connected in star group 68b, the 68b... that is formed on the pump cover 68 extends towards the periphery with curve-like from the center.The end of sagging connected in star 68b peripheral near is offset with respect near the sense of rotation (direction of arrow J) of the end the center along impeller 36.Interval between adjacent sagging connected in star 68b, the 68b... all equates.

There are two types shape in sagging connected in star 68b, 68b....In central authorities, be formed at the sagging connected in star group 68b1 in the regional K (end of regional K stretches to the downstream of groove 68a) that exports the 50a next door, the length of 68b1..., greater than the sagging connected in star group 68b2 in the area L that is formed at except regional K, the length of 68b2..., more close periphery is arranged near therefore peripheral end.In other words, between the end of the sagging connected in star 68b1 peripheral near and the groove 68a internal edge apart from M less than between the end of peripheral sagging connected in star 68b2 near and the groove 68a internal edge apart from N.Flat surfaces is formed in the end and the zone between the groove 68a internal edge of sagging connected in star group 68b, the 68b... periphery near.

As shown in Figure 5, sagging connected in star group 70b, the 70b... that is formed on the pump cover 70 extends towards the periphery with curve-like near the center.The end of sagging connected in star 70b peripheral near is offset with respect near the sense of rotation (direction of arrow P) of the end the center along impeller 36.Interval between adjacent sagging connected in star 70b, the 70b... all equates.

There are two types shape in sagging connected in star 70b, 70b....In centre, be formed at the interior sagging connected in star group 70b1 of regional Q (end of regional Q extends to inlet 42a) on the downstream next door of groove 70a, the length of 70b1..., greater than the sagging connected in star group 70b2 in the region R that is formed at except regional Q, the length of 70b2..., more close periphery is arranged near therefore peripheral end.In other words, between the end of the sagging connected in star 70b1 peripheral near and the groove 70a internal edge apart from S less than between the end of peripheral sagging connected in star 70b2 near and the groove 70a internal edge apart from T.Flat surfaces is formed in the end and the zone between the groove 70a internal edge of sagging connected in star group 70b, the 70b... periphery near.

In Wesco pump according to second embodiment, be similar to Wesco pump 10 according to first embodiment, sink connected in star group 68b, 68b... and sagging connected in star group 70b, 70b... are formed in the pump cover 68 respectively and in the pump case 70.In pump cover 68, sagging connected in star group 68b1, the 68b1... of (regional K) are long near the outlet 50a, and the sagging connected in star group 68b2, the 68b2... that are formed in other zones (area L) are short.In pump case 70, near sagging connected in star group 70b1, the 70b1... the downstream of groove 70a in (regional Q) is long, and sagging connected in star group 70b2, the 70b2... in other zones (region R) is short.In the regional K and Q that form long recess, more fuel encloses outward from the center and is pushed into, and the pressure reduction that therefore acts on impeller 36 end faces and bottom surface is cancelled.Like this, can suppress the inclination of impeller 36, and the contact between impeller 36 and the pump case 68,70 can be inhibited with respect to axle.In addition, in the area L and R that form short groove, because therefore big flat surfaces can keep sealing.As a result, can reduce from the fuel leak of pump stream.

In above-mentioned first embodiment and second embodiment, sink connected in star 38b, 40b, 68b, 70b are formed near the entrance and exit area B, F, K, the Q simultaneously and other zone C, G, L, R in.Yet, the invention is not restricted to such structure.For example, near the zone that sagging connected in star can be formed at the entrance and exit is interior with generation power, thereby offsets the end face of impeller and the pressure reduction on the bottom surface as much as possible, but in other zones, this sagging connected in star can omit.This is because in the zone except the entrance and exit near zone, the pressure reduction that acts on end face and bottom surface is very little.By only near entrance and exit, forming the connected in star group of sinking, can further improve sealing, and can reduce effectively from the fuel leak of pump stream.

In addition, can obtain similar effect by the shape (for example recess width, depth of groove, inflow angle etc.) (seeing Table 1) that changes the connected in star that sink.For example, as shown in Figure 6, in the area B that pressure reduction is big on impeller top surface and bottom surface, the width of the connected in star 88b that sink can increase, and in the little zone C of this pressure reduction, the width of the connected in star 88b that sink can reduce.Perhaps, as shown in Figs. 7-9, in the area B that pressure reduction is big on impeller top surface and bottom surface, the degree of depth t2 of the connected in star 98b that sink can increase (see figure 9), and in the little zone C of this pressure reduction, the degree of depth t1 of the connected in star 98b that sink can reduce (see figure 8).In addition, in the zone that pressure reduction is big on impeller top surface and bottom surface, inflow angle can form acute angle, and in the zone that pressure reduction is little on impeller top surface and bottom surface, inflow angle can form the obtuse angle.

Table 1

	Big pressure reduction	Small pressure difference
			The groove number	A plurality of	Seldom
Groove length	Long	Short
			Recess width	Greatly	Little
Depth of groove	Deeply	Shallow
			Inflow angle	Acute angle	The obtuse angle

In addition, in first and second embodiments, in pump cover and pump case, all form the connected in star that sink, but the connected in star that sink can be formed at pump cover or pump case on any one.This be because, according to the structure of type of fluid of being pressurizeed and entrance and exit etc. by Wesco pump, only pump cover or pump case one of on form the inclination that the connected in star that sink can suppress impeller.

Can select rightly the to sink number, length, sectional shape of connected in star etc.

Third generation table embodiment

Below be explained with reference to the drawings Wesco pump 110 according to the 3rd embodiment.Be similar to structure according to the structure proximate of the 3rd embodiment's Wesco pump 110 according to first embodiment's Wesco pump 10.And be that the connected in star group of sinking is formed on the impeller, and the gap between impeller and the pump case radially changes according to the 3rd embodiment's Wesco pump with difference according to first embodiment's Wesco pump 10.Here only explain in detail and first embodiment's difference, and omission to the explanation of first embodiment's common ground.

As shown in figure 10, Wesco pump 110 comprises electric motor units 112 and pump unit 114.Electric motor units 112 has and the structure identical according to the electric motor units 12 of first embodiment's Wesco pump 10.Pump unit 114 comprises the pump case 139 that is approximately discoidal impeller 136 and holds impeller 136.

As shown in figure 11, D shape through hole 136f is formed at the center of impeller 136.Through hole 136f cooperates with the bottom of rotating shaft 120.Therefore, impeller 136 can be along the moving axially of rotating shaft 120, but can't 120 rotations of phase countershaft.Therefore, when rotating shaft 120 rotations, impeller 136 also rotates.

The end face of impeller 136 and bottom surface form the plane approximately perpendicular to rotating shaft 120.On the end face of impeller 136, form sets of recesses 136a, 136a... along peripheral, and sagging connected in star group 136c, 136c... radially are located at core along impeller 136.On the bottom surface of impeller 136, form sets of recesses 136b, 136b... along peripheral, and sagging connected in star group 136d, 136d... radially are located at core.The sets of recesses 136a, the 136a... that are formed in impeller 136 end faces link to each other in concave bottom with sets of recesses 136b, 136b... in being formed at the bottom surface.

As Figure 11 and shown in Figure 12, the sagging connected in star 136c that is formed on impeller 136 end faces extends towards near its end 137a peripheral with curve-like (helical) near its end 137c the center.In addition, there is distance A between the end 137a of sagging connected in star 136c and the recess 136a.In other words, flat surfaces is formed between end 137a, the 137a... and sets of recesses 136a, 136a... of sagging connected in star group 136c, 136c... of periphery near.In addition, flat surfaces also is formed between the surface of peripheral 136e of sets of recesses 136a, 136a... and impeller 136.

Although not shown, be formed at sagging connected in star 136d on impeller 136 bottom surfaces to form with the aforesaid identical mode of sagging connected in star 136c on the end face that is positioned at.In addition, flat surfaces is formed between the end and sets of recesses 136b of periphery of the connected in star group 136d that sink.In addition, flat surfaces also is formed between the surface of peripheral 136e of sets of recesses 136b, 136b... and impeller 136.

Pump case 139 comprises the pump cover 138 and the pump housing 140.Cone shape is formed on the pump case surface 138b of pump cover 138, so that itself and the periphery increase towards impeller 136 from the center of impeller 136 of the gap of impeller 136.Groove 138a is formed on the 138b of pump case surface, and relative with sets of recesses 136a on being located at impeller 136 end faces.The pump case of the pump housing 140 surface 140b forms taper, so that the periphery towards impeller 136 increases from the center of impeller 136 with the gap of impeller 136.Groove 140a is formed on the 140b of pump case surface, and relative with sets of recesses 136b on being located at impeller 136 bottom surfaces.Groove 138a and 140a form from the upstream extremity to the downstream the approximate C shape along impeller 136 sense of rotation.The upstream extremity of groove 140a forms the inlet 142 in its connection pump housing 140.The downstream of groove 138a forms the outlet 150 in its connection pump cover 138.Form the first pump stream 144 by the groove 138a that is formed at the sets of recesses 136a in impeller 136 end faces and be formed in the pump cover 138.Form the second pump stream 146 by the groove 140a that is formed at the sets of recesses 136b in impeller 136 bottom surfaces and be formed in the pump housing 140.In Figure 10 and Figure 13, the cone angle on pump case surface 138b and the pump case surface 140b is exaggerated so that observe.In the reality, the cone angle of pump case surface 138b and pump case surface 140b is very little.

When impeller 136 rotated in pump case 139, fuel 142 was inhaled into pump unit 114 from entering the mouth, and is directed to pump stream 144,146.Pass 144,146 o'clock pressurized fuel of pump stream and be pushed into towards electric motor units 112 flowing from exporting 150.The fuel that is pushed into towards electric motor units 112 passes through electric motor units 112, and is advanced to the external world from the exhaust port 148 that is formed on the top cover 132.

When impeller 136 rotations, the fuel in the gap between impeller 136 and pump case 138, the pump housing 140 is inhaled among sink connected in star group 136c, the 136c... and among sagging connected in star group 136d, the 136d....The fuel that is inhaled among sink connected in star group 136c, the 136c... guides by the wall 137b on the side that is positioned at sagging connected in star group 136c, 136c..., and flows near the peripheral end 137a (with reference to Figure 12) of sink connected in star group 136c, 136c....Similarly, on the bottom surface of impeller 136, fuel is inhaled among sink connected in star group 136d, the 136d..., and flow in the end towards the periphery in sink connected in star group 136d, 136d....In sagging connected in star group 136c, 136c... and sagging connected in star group 136d, 136d..., enclose the fuel that is pushed into outward from the center, pump case surface 138b and pump case surface 140b are exerted pressure, and to impeller 136 produce lift (that is, along increase with pump case surface 138b and with the power of the direction in the gap of pump case surface 140b).These lift prevented impeller 136 and pump case surface 138b or and pump case surface 140b between contact.Along with the gap between impeller 136 and pump case 138, the pump housing 140 reduces, the lift that acts on the impeller 136 increases.In the Wesco pump 110 according to present embodiment, pump case surface 138b and pump case surface 140b are formed with taper, so that the periphery towards impeller 136 increases from the center of impeller 136 with the gap of impeller 136.In other words, in the position that has formed sagging connected in star group 136c, 136c... and sagging connected in star group 136d, 136d..., the gap between impeller 136 and pump case 138, the pump housing 140 is little.Therefore, bigger lift acts on impeller 136.Like this, can further reduce frictional loss and wearing and tearing.

Below explain the lift that when impeller 136 rotations, produces in detail by sink connected in star group 136c, 136c... and 136d, 136d....As previously mentioned, when impeller 136 rotation, fuel 142 is introduced into the pump stream 144,146 from entering the mouth, and this fuel is pressurized inflow pump stream 144,146 o'clock.Therefore, the closer to pump stream 144,146 upstreams, fuel pressure is low more, and the closer to the downstream of pump stream 144,146, fuel pressure is high more.In addition, pump stream 144,146 is formed on the end face and bottom surface of impeller 136, because the pressure reduction of the fuel that flows in the first pump stream 144 and the second pump stream 146, impeller 136 is subjected to the power along thrust direction thus.The pressure reduction of the fuel that flows in the first pump stream 144 and the second pump stream 146 changes according to the position on the circumferencial direction of impeller 136.Therefore, impeller 136 is subjected to uneven power, makes impeller 136 tilt slightly.On the other hand, the pump case of pump case 139 surface 138b, 140b are formed with taper, so that the periphery towards impeller 136 increases from the center of impeller 136 with the gap of impeller 136.Therefore, even impeller 136 slight inclination, the periphery of impeller 136 does not contact pump case surface 138b, 140b (with reference to Figure 13).In addition, if impeller 136 slight inclination, the part (part among Figure 13 on the right side) of sagging connected in star group 136c, 136c... is near pump case surface 138b, and the part of sagging connected in star group 136d, 136d... (part among Figure 13 on the left side) is near pump case surface 140b.So in the approaching position of these parts, the pressure of fuel increases in sink connected in star group 136c, 136c... and sagging connected in star group 136d, the 136d..., so the pressure on pump case surface 138b and the pump case surface 140b increases.This increased pressure acts on the direction that prevents impeller 136 inclinations, makes impeller 136 turn back to flat-hand position.Therefore, even impeller 136 slight inclination, impeller 136 is owing to the lift that sink connected in star group 136c, 136d produce is tending towards turning back to level.Therefore, the contact between impeller 136 and pump case surface 138b, the 140b is prevented from, and frictional loss can reduce with wearing and tearing.

According to the Wesco pump 110 of present embodiment, the lift of impeller 136 increases, thereby can suppress frictional loss and wearing and tearing.In addition, even impeller 136 slight inclination also can prevent the contact between impeller 136 and pump case surface 138b, the 140b.In addition, because the lift that sink connected in star group 136c, 136d produce, the masterpiece that is tending towards level that impeller 136 is returned to is used for impeller 136.Like this, can improve pump performance effectively.

In addition, in the Wesco pump 110 according to present embodiment, sink connected in star group 136c, 136c... and sagging connected in star group 136d, 136d... are formed on the impeller 136 of rotation, thereby produce the lift that acts on the impeller 136.Therefore, except centrifugal force and viscous force, inertial force also acts on the fuel in sink connected in star group 136c, 136c... and sagging connected in star group 136d, the 136d....Because the synergy of these power can produce more effective lift.

In addition, in the Wesco pump 110 according to present embodiment, sink connected in star group 136c, 136d are from extending towards the periphery of impeller 136 with curve-like (helical) near the center of impeller 136.Therefore, the fuel that is inhaled into can more effectively flow to the periphery, and can obtain bigger lift.

In above-mentioned Wesco pump 110, be formed at sagging connected in star group 136c, 136d on the impeller 136 from extending towards the periphery of impeller 136 with curve-like near the center of impeller 136.Yet, the invention is not restricted to this form.Can select to be formed at the number, length, sectional shape of the sagging connected in star on the impeller etc. rightly.In addition, sagging connected in star group 136c, 136d can be formed on pump case surface 138b, the 140b.

In addition, in the present embodiment, pump case surface 138b and pump case surface 140b form cone-shaped, so that increase towards the periphery near the center of impeller 136 with the gap of impeller 136.Yet, the invention is not restricted to this form.For example, the end face of impeller 136 and bottom surface can form taper, so that increase towards the periphery near the center of impeller 136 with the gap of pump case surface 138b, 140b.

The 4th representative embodiment

Below be explained with reference to the drawings Wesco pump 210 according to the 4th embodiment.According to the approximate Wesco pump 10 that is similar to according to first embodiment of the structure of the 4th embodiment's Wesco pump 210.Yet the 4th embodiment's Wesco pump is that the connected in star group of sinking only is formed in the bottom surface of impeller, and the gap between impeller top surface and the pump case radially changes with difference according to first embodiment's Wesco pump 10.Here only explain in detail and first embodiment's difference, omission to the explanation of first embodiment's common ground.

As shown in figure 14, Wesco pump 210 comprises electric motor units 212 and pump unit 214.Electric motor units 212 has and the structure identical according to the electric motor units 12 of first embodiment's Wesco pump 10.Pump unit 214 comprises the pump case 239 that is approximately discoidal impeller 236 and holds impeller 236.

The end face of impeller 236 and bottom surface form the plane approximately perpendicular to rotating shaft 220.On the end face of impeller 236, radially form sets of recesses 236b, 236b... continuously outward along being trapped among.On the bottom surface of impeller 236, radially continuously form sets of recesses 236a, 236a... along being trapped among outward, and sagging connected in star group 236c, 236c... be located at the inside of sets of recesses 236a, 236a..., and extend towards the periphery near the center of impeller 236.The sets of recesses 236b, the 236b... that are formed on impeller 236 end faces link to each other in the bottom of recess with sets of recesses 236a, 236a... on being formed at the bottom surface.

As Figure 15 and shown in Figure 16, the sagging connected in star 236c that is formed in impeller 236 bottom surfaces extends towards near its end 237a peripheral with curve-like (helical) near its end 237c the center.In addition, there is distance A between the end 237a of the sagging connected in star 236c the periphery near and the recess 236a.In other words, flat surfaces is formed between end 237a, the 237a... and sets of recesses 236a, 236a... of sagging connected in star group 236c, 236c... of periphery near.In addition, flat surfaces also is formed between the surface of peripheral 236e of sets of recesses 236a, 236a... and impeller 236.

Pump case 239 comprises the pump cover 238 and the pump housing 240.The pump case surface 240b of the pump housing 240 forms and the parallel plane shape in impeller 236 bottom surfaces.Groove 240a is formed in the 240b of pump case surface, and relative with sets of recesses 236a, 236a... on being located at impeller 236 bottom surfaces.The pump case of pump cover 238 surface 238b forms and makes the most close impeller of a part of pump case surface 238b, as shown in figure 17.This part of the most close impeller 236 (protuberance 238c) forms continuous annular along the circumferential direction.Groove 238a is formed on the 238b of pump case surface, and relative with sets of recesses 236b, 236b... on being located at impeller 236 end faces.Groove 238a and 240a form from the upstream extremity to the downstream along the approximate C shape of the sense of rotation of impeller 236.The upstream extremity of groove 240a forms with inlet 242 in the pump housing 240 and is connected.The downstream of groove 238a forms with outlet 250 on the pump cover 238 and is connected.Form the first pump stream 244 by the groove 238a that is formed at the sets of recesses 236b on impeller 236 end faces and be formed on the pump cover 238.Form the second pump stream 246 by the groove 240a that is formed at the sets of recesses 236a on impeller 236 bottom surfaces and be formed on the pump housing 240.

When impeller 236 rotated in pump case 239, fuel 242 was inhaled into pump unit 214 from entering the mouth.The fuel that is inhaled in the pump unit 214 flow to the downstream side from the upstream side of pump stream 244,246.In addition, when fuel flowed in pump stream 244,246, fuel pressure increased.When the fuel that flows in pump stream 244,246 reached the downstream of pump stream 244, fuel was discharged to electric motor units 212 from exporting 250.The fuel that is pushed into towards electric motor units 212 passes through electric motor units 212, and is pulled to the external world from exhaust port 248.

Here explain the power that when impeller 236 rotations, acts on impeller 236.As previously mentioned, when impeller 236 rotations, fuel is pressurized when its upstream side from pump stream 244,246 flow to the downstream side.When impeller 236 rotations, the pressure of fuel is higher than the pressure of fuel in the pump stream 246 in the pump stream 244.In addition, pump stream 244,246 is formed on the end face and bottom surface of impeller 236, and impeller 236 is subjected to the power of the pressure reduction generation of fuel mobile in the first pump stream 244 and the second pump stream 246 thus.In other words, because the pressure reduction of the fuel that flows in the pump stream 244,246, so impeller 236 is subjected to impeller 236 is pressed to the power of pump case surface 240b.

In addition, be discharged to small amount of fuel in the electric motor units 212 from pump unit 214, flow in the gap between the surperficial 238b of impeller 236 end faces and pump case by the gap between rotating shaft 220 and the bearing 228.Flowed into the pressure height of the small amount of fuel in this gap, thus the power that produces of the pressure of this fuel along the directive effect of pump case surface 240b in impeller 236.

In addition, in the gap between small amount of fuel inflow impeller 236 bottom surfaces and the pump case surface 240b.The fuel that has flowed into this gap is inhaled among sink connected in star group 236c, the 236c....The fuel that is inhaled among sink connected in star group 236c, the 236c... is guided by the wall 237b of sagging connected in star group 236c, 236c..., and near the end 237a (with reference to Figure 16) the periphery of the flow direction sagging connected in star group 236c, 236c....From near the fuel in sagging connected in star group 236c, 236c... that the periphery the is pushed into center, 240b exerts pressure to the pump case surface, producing lift (that is, the edge increases the power of the directive effect in the gap between impeller 236 and the pump case surface 240b) on the impeller 236.On the other hand, sagging connected in star is not formed on the end face of impeller 236, therefore can not produce lift between impeller 236 end faces and pump case surface 238b.

Like this, because the masterpiece that the power that the pressure reduction of fuel produces in the pump stream 244,246, the power that produces by the pressure of the gap between rotating shaft 220 and the bearing 228 from electric motor units 212 flow upstream to the fuel of pump unit 214 and sagging connected in star group 236c, 236c... cause is used for impeller 236.Because the power that the pressure reduction of fuel produces and because the masterpiece that the pressure of the fuel of flow upstream produces is used for impeller 236 is pressed to the direction of pump case surface 240b.The lift that is caused by sink connected in star group 236c, 236c... is along offsetting the directive effect of impeller 236 being pressed to the power of pump case surface 240b.Can not be pressed towards pump case surface 240b when therefore, impeller 236 rotates.Like this, the contact between the surperficial 240b of can draw up impeller 236 and pump case, and can reduce friction loss and wear and tear.

As previously mentioned, in Wesco pump 210, sink connected in star group 236c, 236c... are formed on the bottom surface of impeller 236, and sagging connected in star is not formed on impeller 236 end faces and the pump case surface 238b.Therefore, by the lift that produces by sink connected in star group 236c, 236c..., can offset the power of impeller 236 being pressed to pump case surface 240b.Like this, can suppress impeller 236 to be pressed to pump case surface 240b and prevent that impeller 236 from contacting with pump case surface 240b.

In addition, in Wesco pump 210, protuberance 238c is formed on the 238b of pump case surface, the inside of sets of recesses 236b, 236b..., to form the continuous annular along impeller 236 circumferencial directions.The gap of protuberance 238c and impeller 236 is less than other parts of pump cover and the gap of impeller, and therefore the fuel leak that enters by protuberance 238c the gap of outlet side from the pump stream is inhibited.Therefore, can reduce from the fuel leak of pump stream 244.Like this, the fuel in the pump case can be pressurizeed effectively, and can obtain high pump performance.

In addition, even because the fluctuation of the fuel pressure in the pump stream 244,246 makes the power that impeller 236 is pressed to pump case surface 238b increase, the pressure that flows to the fuel of pump unit 214 by the gap between rotating shaft 220 and the bearing 228 from electric motor units 212 can suppress contacting of impeller 236 and pump case surface 238b.In addition, even hypothesis impeller 236 and pump case surface 238b contact, impeller 236 will only contact protuberance 238c, so the frictional loss can minimize and suppress impeller and contact with pump case the time.

The 5th representative embodiment

As mentioned above, in the Wesco pump 210 according to the 4th embodiment, sagging connected in star only is formed on the bottom surface of impeller 236, but the connected in star that should sink also can be formed in the end face of impeller.Below explain the Wesco pump 310 according to the 5th embodiment, the connected in star that wherein sink is formed on the end face of impeller.In this omission or the simplification explanation identical with the 4th embodiment.

Wesco pump 310 according to the 5th embodiment comprises electric motor units and pump unit 314.Electric motor units has and the structure identical according to first embodiment's Wesco pump 10.Pump unit 314 comprises the pump case 339 that is approximately discoidal impeller 336 and holds impeller 336.

The structure proximate of impeller 336 is similar to the impeller 236 according to the 4th embodiment.In other words, in the end face of impeller 336, form sets of recesses 336b, 336b....On the bottom surface of impeller 336, form sets of recesses 336a, 336a... and sagging connected in star group 336c, 336c....

In addition, sagging connected in star group 336d, 336d... are formed on the end face of impeller 336.As shown in figure 19, the shape of connected in star 336d of sinking is identical with sagging connected in star 336c on being formed at impeller 336 bottom surfaces.In other words, sagging connected in star 336d extends towards near the end peripheral near the end the center with curve-like (helical).Yet the number of the connected in star 336d that sink is less than the number (seeing Figure 15 and Figure 19) of the connected in star 336c that sink.

Pump case 339 comprises the pump cover 338 and the pump housing 340.Identical with according to the 4th embodiment's the pump housing 240 of the pump case of the pump housing 340 surface 340b, groove 340a and 342 the generation type of entering the mouth.As shown in figure 18, the pump case of pump cover 338 surface 338b forms the plane shape parallel with the end face of impeller 336.In addition, identical with according to the 4th embodiment's pump cover 238 of the groove 338a of pump cover 338 and outlet 350 generation type.Form the first pump stream 344 by the groove 338a that is formed at the sets of recesses 336b in impeller 336 end faces and be formed in the pump cover 338.Form the second pump stream 346 by the groove 340a that is formed at the sets of recesses 336a in impeller 336 bottom surfaces and be formed in the pump housing 340.

Here explain the power that when impeller 336 rotations, acts on impeller 336.Similar with the 4th embodiment, the masterpiece that the pressure reduction of the fuel that flows in the first pump stream 344 and the second pump stream 346 produces is used for impeller 336.In addition, flow into the fuel generation power in the gap between impeller 336 end faces and the pump case surface 338b by the gap between rotating shaft and the bearing from electric motor units.These masterpieces are used for impeller 336 is pressed to the direction of pump case surface 340b.

In addition, sagging connected in star group 336c, the 336c... that is formed in impeller 336 bottom surfaces produces lift B.This lift B acts on the direction that the gap between impeller 336 bottom surfaces and the pump case surface 340b is increased.

In addition, the sagging connected in star group 336d, the 336d... that are formed on impeller 336 end faces produce lift C, and this lift C acts on the direction that the gap between impeller 336 end faces and the pump case surface 338b is increased.As previously mentioned, the groove number of sagging connected in star group 336d, 336d... is less than the groove number of sink connected in star group 336c, 336c....Therefore, lift C is less than lift B.

Like this, when impeller 336 rotation, owing to the power that the fuel pressure difference that flow in the pump stream 344,346 produce, flow to power, lift B and the lift C that the pressure of the fuel the pump pump case 339 produces from electric motor units and act on impeller 336.Owing to the power of fuel pressure difference generation, because power that the pressure of the fuel of flow upstream produces and lift C act on the direction of impeller 336 being pressed to pump case surface 340b.Lift B acts on the direction of these power of counteracting.Lift B is greater than lift C, therefore will deduct the power that lift C obtains and can be used for offsetting because power that fuel pressure difference produces and because the power that the pressure of the fuel of flow upstream produces from lift B.Therefore, can suppress contacting of impeller 336 and pump case surface 340b, and impeller 336 can rotate swimmingly.Like this, can improve the efficient of pump.

In addition, if impeller 336 is owing to fuel pressure fluctuates etc. compresses pump case surface 338b, then the gap between the 338b of impeller 336 end faces and pump case surface reduces.So the fuel in this gap is compressed, and lift C increases.The lift C that impeller 336 is increased exerts pressure, thereby turns back to the home position.Therefore, can draw up the contacting of impeller 336 and pump case surface 338b.

As mentioned above, in the 5th embodiment, the groove number by making sink connected in star group 336d, 336d... makes lift C (promptly less than the groove number of sink connected in star group 336c, 336c..., to the power that presses down impeller) size less than lift B (that is, upwards pressing the power of impeller).Yet, the invention is not restricted to this form.For example, as shown in figure 20, the length of the sagging connected in star 436d on the impeller top surface can form the length less than the sagging connected in star on the impeller bottom surface.In addition, as shown in figure 21, the width of the sagging connected in star 536d on the impeller top surface can form the width less than the sagging connected in star on the impeller bottom surface.Perhaps, as shown in figure 22, the inflow angle of the sagging connected in star 636d on the impeller top surface (that is the angle θ (with reference to Figure 23) that forms between the fuel flow direction in sagging connected in star and the gap) can form the inflow angle greater than the sagging connected in star on the impeller bottom surface.In addition, the degree of depth of the sagging connected in star on the impeller top surface can form the depth as shallow than the sagging connected in star on the impeller bottom surface.Like this, according to the shape of the sagging connected in star on the impeller bottom surface,, can make lift C less than lift B by determining to be formed at the shape of the sagging connected in star on the impeller top surface.

In addition, in each previous embodiment, be formed at sagging connected in star on impeller or the pump case from extending towards the periphery with curve-like (helical) near the center of impeller.Yet, the invention is not restricted to this form.Can suitably design be formed in the impeller or pump case in the number, length, sectional shape etc. of sagging connected in star.

At last, although described preferred embodiment in detail, these embodiments are schematic and nonrestrictive.Should be appreciated that, under the situation that does not deviate from the spirit and scope of the present invention, can carry out various changes and modification.In addition, disclosed supplementary features and aspect also can be used separately or use in conjunction with above-mentioned aspect and feature among the application.

Claims (12)

1. pump, comprise pump case and in this pump case, rotate, be approximately discoidal impeller, wherein

On the obverse and reverse of this impeller, all be formed with sets of recesses, form the circumferencial direction repeated arrangement of a plurality of recesses of each sets of recesses along this impeller;

With the first positive relative pump case internal surface of this impeller on be formed with first groove, this first groove with the described sets of recesses of this impeller in one group of zone of facing in extend to downstream from upstream extremity;

On the second pump case internal surface relative, be formed with second groove with the reverse side of this impeller, this second groove with the described sets of recesses of this impeller in the zone faced of another group in extend to downstream from upstream extremity;

On this pump case, be formed with entrance and exit, this inlet makes this first groove be connected with the outside of this pump case with one upstream extremity in second groove, and this outlet makes another the downstream in this first groove and second groove be connected with the outside of this pump case; And

At least on this first pump case internal surface and the second pump case internal surface, be formed with the connected in star group of sinking, described sagging connected in star group is enclosed extension outwardly from the center, and along the skew of the sense of rotation of this impeller, described sagging connected in star group asymmetricly forms according to the position of this first groove and second groove running shaft with respect to this impeller.

2. pump according to claim 1, wherein in this pump case internal surface near the zone of outlet and/or in this pump case internal surface in the zone near inlet, act on lift on this impeller greater than the lift in other zones by what described sagging connected in star group produced.

3. pump according to claim 1, wherein said sagging connected in star group only are formed near zone and/or near the zone of this inlet this outlet.

4. pump according to claim 3, each the sagging connected in star that wherein forms described sagging connected in star group from the center of this impeller towards the periphery of this impeller with spiral extension.

5. pump, comprise pump case and in this pump case, rotate, be approximately discoidal impeller, wherein

On the obverse and reverse of this impeller, all be formed with sets of recesses, form the circumferencial direction repeated arrangement of a plurality of recesses of each sets of recesses along this impeller;

With the first positive relative pump case internal surface of this impeller on be formed with first groove, this first groove with the described sets of recesses of this impeller in one group of zone of facing in extend to downstream from upstream extremity;

On the second pump case internal surface relative, be formed with second groove with the reverse side of this impeller, this second groove with the described sets of recesses of this impeller in the zone faced of another group in extend to downstream from upstream extremity;

On this pump case, be formed with entrance and exit, this inlet makes this first groove be connected with the outside of this pump case with one upstream extremity in second groove, and this outlet makes another the downstream in this first groove and second groove be connected with the outside of this pump case;

On at least one face among reverse side, this first pump case internal surface and this second pump case internal surface of the front of this impeller, this impeller, be formed with sagging connected in star, so that the fluid in the gap between this impeller and this pump case is pressurized, and when rotating, impeller increases the direction generation power in the gap between this impeller and this pump case; And

When this impeller does not tilt with respect to this pump case, be formed with the face of described sagging connected in star and the gap between the face relative and increase towards the periphery of this impeller from the center of this impeller with it.

6. pump according to claim 5, wherein be formed with the face of described sagging connected in star and a face in the face relative and form flat surfaces, and another face forms taper, and the periphery towards this impeller increases so that the gap of this another face and this impeller is from the center of this impeller with it.

7. pump according to claim 6, wherein said sagging connected in star from the center of this impeller towards the periphery of this impeller with spiral extension.

8. pump, comprise pump case and in this pump case, rotate, be approximately discoidal impeller, wherein

On the obverse and reverse of this impeller, all be formed with sets of recesses, form the circumferencial direction repeated arrangement of a plurality of recesses of each sets of recesses along this impeller;

With the first positive relative pump case internal surface of this impeller on be formed with first groove, this first groove with the described sets of recesses of this impeller in one group of zone of facing in extend to downstream from upstream extremity;

On the second pump case internal surface relative, be formed with second groove with the reverse side of this impeller, this second groove with the described sets of recesses of this impeller in the zone faced of another group in extend to downstream from upstream extremity;

Be formed with entrance and exit on this pump case, this inlet makes the upstream extremity of the pump stream that formed by described sets of recesses, this first groove and second groove be connected with the outside of this pump case, and this outlet makes the downstream of this pump stream be connected with the outside of this pump case;

Be formed at least one surface in inlet side impeller surface and the inlet side pump case internal surface with described a plurality of sagging connected in stars of this pump stream sealing, and neither be formed at the outlet side impeller surface with described a plurality of sagging connected in stars of this pump stream sealing and also be not formed on the outlet side pump case internal surface.

9. pump according to claim 8 wherein is formed with the circumferencial direction protuberance circlewise along this impeller on this outlet side pump case internal surface.

10. pump according to claim 9, wherein said sagging connected in star from the center of this impeller towards the periphery of this impeller with spiral extension.

11. pump according to claim 8, further comprise: be arranged at the motor room of this pump case outside and be contained in motor in this motor room, wherein this motor comprises rotatable axle, this outlet connects this pump stream and this motor room, the through hole that this motor shaft penetrates is formed in this pump case, and the other end of this motor shaft is installed on this impeller.

12. a pump, comprise pump case and in this pump case, rotate, be approximately discoidal impeller, wherein

On the obverse and reverse of this impeller, all be formed with sets of recesses, form the circumferencial direction repeated arrangement of a plurality of recesses of each sets of recesses along this impeller;

With the first positive relative pump case internal surface of this impeller on be formed with first groove, this first groove with the described sets of recesses of this impeller in one group of zone of facing in extend to downstream from upstream extremity;

On the second pump case internal surface relative, be formed with second groove with the reverse side of this impeller, this second groove with the described sets of recesses of this impeller in the zone faced of another group in extend to downstream from upstream extremity;

Be formed with entrance and exit on this pump case, this inlet makes the upstream extremity of the pump stream that described sets of recesses, this first groove and second groove form be connected with the outside of this pump case, and this outlet makes the downstream of this pump stream be connected with the outside of this pump case;

The inlet side connected in star that sink is formed at least one surface in inlet side impeller surface and the inlet side pump case internal surface, so that fluid is pressurized and produce lift when the rotation of this impeller, this lift is along the directive effect that increases the gap between this inlet side impeller surface and this inlet side pump case internal surface;

The outlet side connected in star that sink is formed at least one surface in outlet side impeller surface and the outlet side pump case internal surface, so that fluid is pressurized and produce lift when the rotation of this impeller, this lift is along the directive effect that increases the gap between this outlet side impeller surface and this outlet side pump case internal surface; And

According to number and/or shape that the number and/or the shape of the sagging connected in star of this inlet side are determined the sagging connected in star of this outlet side, the lift that connected in star produces so that this outlet side sink is less than the lift of the sagging connected in star generation of this inlet side.

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