CN101356374B - fluid pump - Google Patents

Abstract

The invention relates to an embodiment of a semi-axial-flow electric fluid pump, in which a support rib (31) is arranged between a radially outer pump housing part (32) which radially surrounds the electric motor (1) and a radially inner first motor housing part (8), wherein the radially outer pump housing part (32) is designed in one piece with the first motor housing part (8) and the support rib (31). The wall thickness of the pump housing can therefore be made smaller than in the known embodiments, since sufficient strength is obtained by the support ribs. Thus, the number and weight of the components are reduced.

Description

fluid pump

The invention relates to a fluid pump for an internal combustion engine, which has an electric motor with a rotor arranged in a motor housing and a stator, wherein the rotor is arranged at least in a rotationally fixed manner on a drive shaft, a fixed impeller on the drive shaft, at least one guide impeller arranged behind said impeller in the flow direction of the fluid to be conveyed, and a pump housing surrounding the motor housing, impeller and guide impeller, and A pressure connection and a suction connection are arranged opposite each other at the two axial ends of the pump housing, between a radially outer pump housing part and a radially inner first motor housing part The supporting rib, the motor housing part radially surrounds the motor, wherein the radially outer pump housing part is formed in one piece with the motor housing part and the supporting rib.

Fluid pumps for internal combustion engines are used in particular as coolant pumps in coolant circuits. Although in the past there was a direct connection to the speed of the electric motor and the pump was driven via a belt drive or a chain drive, in newer engines more and more speed-adjustable electric coolant pumps with slotted tubes are used, for modern thermal management. An excess of delivered power can thus be avoided, so that, for example, the internal combustion engine can be heated up more quickly after a cold start. The delivery volume can be adjusted according to the actual required cooling power.

For example, MTZ Nr. 11 2005 (pages 872-877) discloses a pump of this type. Such an electric coolant pump includes an EC electric motor as drive and has a pump head with an axial inlet and a tangential outlet. However, the components used here, and especially the housing part, are too large for the power consumption of the pump, so that a larger drive motor must be used.

Therefore, US2002/0106290 A1 discloses a semi-axial flow electrofluid pump. When the power consumption of the motor is the same, the use of this semi-axial structure makes the motor can be designed to be smaller in order to achieve a larger rotating speed. The same throughput is achieved with a smaller structure. The electrofluid pump has a completely enclosed electric motor, on the outside of which a guide impeller is formed. Seen in the direction of flow, however, behind the guide vane there is formed an obstacle preventing electrical contact with the electronic unit from being established.

On the impeller side, the entire motor is sealed against the environment by a seal. The extent to which such seals on rotating parts are adequate is at least debatable.

The housing of the pump is designed in two parts and has different steps and through-holes for electrical contact. Different motors and housings are developed according to the highest desired throughput. Due to the short guide vanes, a completely swirl-free flow will most likely not be possible. Furthermore, the pressure losses due to the through-holes for the electrical contacts are also relatively high, so that the gain with respect to the power consumption of the electric machine is partially impaired by the pressure losses that occur.

FR 2.222.885 discloses a semi-axial flow pump with a multi-segment housing whose middle section surrounds the motor and serves as a single motor and pump housing, wherein the pump housing and the motor housing pass through Support rib connection. The electrical contacts are guided outwards behind these housing parts in the flow direction via additional conduits.

DE 20 201 183 U1 discloses an axial flow pump which likewise has such an integral motor and pump housing part. But no outwardly facing electrical contacts are disclosed.

In both pumps, the support ribs are designed straight and therefore do not act as guide impellers to reduce swirl, but instead generate high pressure losses, since the energy of the tangential components of the flow is converted almost completely into frictional losses.

Therefore, the technical problem to be solved by the present invention is to reduce the size of the pump and thus also the motor at the same delivery rate and to avoid pressure losses, ie to increase the efficiency of the pump. Furthermore, the weight and the number of parts of the pump should be reduced.

This technical problem is solved in that the supporting ribs are designed in such a way that they serve as guide impellers of the fluid pump and have such a width that electrical contact elements can pass from the electronics unit through one or more supporting ribs A hole in the center leads to the stator winding. The supporting ribs therefore take on the additional function of converting the tangential flow component into an axial flow component without higher pressure losses. Efficiency is increased and the number of parts is reduced. Electrical contacts passing through the ribs reduce flow resistance and increase pump efficiency because structures inside the flow are eliminated. Compared to known embodiments, the wall thickness of the pump housing can be reduced since sufficient strength is achieved by the supporting ribs. Therefore, the number and weight of parts are reduced.

In a further developed embodiment, the radially outer pump housing part is designed cylindrically, so that the connection of the suction-side pump housing part and the pressure-side pump housing part can be easily produced and a small loss.

In a particular embodiment, the suction-side pump housing part that expands in the direction of flow is formed in one piece with the housing part of an upstream valve. Thus, a modular construction with upstream bypass valves or thermostat valves can be realized, which again reduces components and saves costs.

The first motor housing part preferably delimits the motor on the suction side. Production, for example by aluminum die-casting, can still be carried out inexpensively, which in turn leads to a reduced number of parts, a lower susceptibility to corrosion and avoids assembly errors.

A motor has thus been created which has a low number of parts, low weight, is easy to assemble, has reduced flow losses and thus has an increased efficiency relative to known pumps.

An embodiment of the invention is shown in the drawing and described below.

The figure shows a side view of a fluid pump according to the invention in a sectional view.

The fluid pump shown in the figure is particularly suitable for use as a cooling pump in an internal combustion engine and is driven by an electronically controlled electric motor 1 consisting of a stator 2 and a rotor 4 arranged on a drive shaft 3 . At the axial end of the drive shaft 3 there is arranged an impeller 5 which is of semi-axial design and which rotates the fluid to be conveyed, in particular coolant, from the suction connection 6 substantially axially through the fluid The pump delivers to the pressure connection 7.

The electric motor 1 is arranged in a motor housing which is composed of a first suction-side motor housing part 8 and a pressure-side second motor housing part 9 . The drive shaft 3 , on which the impeller 5 is arranged, passes through the suction-side motor housing part 8 . For this purpose, the suction-side motor housing part 8 has a bore 10 in which a first bearing 11 for supporting the drive shaft 3 is arranged. Viewed from the suction side, a ceramic thrust plain bearing 12 and rubber collar 13 as well as a spacer 14 are located behind the first bearing 11 . As a result of this assembly, the drive shaft 3 of the electric motor 1 is mounted on the side of the impeller in a sufficiently vibration-damping manner. The spacer is used to lengthen the distance between the first bearing 11 and the second bearing 15 , so that the angle error during manufacture of the hole 10 for accommodating the bearings can be better balanced. Arranged on the shaft behind the spacer 14 is a rotor lamination 16 again, which has axially extending slots for accommodating magnets 17 which are associated with a stator winding 18 in a known manner. match. The rotor 4 is delimited axially and radially by an enclosure 19 . The stator winding 18 is wound on an insulator 20 and axially delimits a stator lamination 21 in a known manner. To close the magnetic circuit, the stator laminations 21 are positively connected to a yoke 22 . The yoke 22 rests against a stop 23 which is formed on the inner surface of the first suction-side motor housing part 8 .

The rotor 4 is separated from the stator 2 by a slot tube 24 which abuts on the suction side of the pump in a corresponding receiving opening 25 of the motor housing part 8 on the suction side and whose opposite axial end is in turn It is arranged in a corresponding receiving opening 26 of the motor housing part 9' on the pressure side. The stator 2 with its sensitive winding 18 is thus located in a dry space separated by the two motor housing parts 8 and 9 and the slot tube 24 .

Arranged at the pressure-side end of the slot tube 24 is a closure element 27 in which the second bearing 15 for supporting the drive shaft 3 is arranged. The locking element 27 is fixed axially by the pressure-side motor housing part 9 , which is arranged with a seal 28 in between in a receiving opening 29 of the suction-side motor housing part 8 .

The stator winding 18 is contacted radially through the pressure-side motor housing part 9 via a bore 30 . In order to prevent the flow losses caused by this additional built-in component, as is known in the prior art, the hole is guided through the support rib 31 which is necessary for sufficient strength of the pump housing and its fastening. For this purpose, the supporting ribs 31 have sufficient width and are configured like an airfoil so that no constriction of the cross section occurs. An electrical contact element (not shown) can now be guided through opening 30 to an electronic unit (not shown), which is used to control electric machine 1 .

In the embodiment shown, the support rib 31 is formed in such a way that it simultaneously serves as a guide vane, so that no additional guide vane is required directly downstream of the impeller 5 . This allows the suction-side motor housing 8 to be produced simply in one piece with the support ribs and the radially outer cylindrical pump housing part 32 . The pump housing part 32 encloses the radially inner motor housing part 8 and the entire motor 1 .

Two identical pump housing parts 33 , 34 are fastened on the downstream side and upstream side of the housing parts 8 , 31 , 32 respectively with a seal 50 in between by means of screw connections. The suction-side pump housing part 33 , which expands in the direction of flow, comprises the suction connection 6 designed as a cylindrical section 35 and an adjoining, expanded section 36 . The semi-axial impeller 5 of the fluid pump is arranged in the transition region 37 between the first section 35 and the second section 36 . In the present embodiment, a cylindrical section 38 of shorter design and larger diameter adjoins the expanded section 36 in order to achieve a smooth transition to the cylindrical pump housing part 32 .

Correspondingly, the pressure-side pump housing part 34 also has a constricted section and a cylindrical section, as seen in the flow direction, wherein the same reference numerals are used due to the uniformity of the individual parts.

Furthermore, grooves 39 are formed on the same pump housing parts 33 , 34 , into which grooves the radial ends 40 of the return guide vanes 41 engage. The return vane 41 serves as an outlet flow guide 42 by means of which a completely turbulent-free flow behind the pressure connection 7 can be achieved. The outlet flow guide 42 is formed on the surface 43 of the motor housing part 9 on the pressure side and is therefore necessary because the support ribs 31 serving as guide vanes are designed to be relatively short and in these areas of the fluid pump usually A completely swirl-free flow cannot be achieved. Furthermore, the motor housing part 9 on the pressure side can be made of plastic, whereas the motor housing part 9 on the suction side can be made of aluminum if possible and is therefore more expensive. The implementation of the guide vane in this region requires a relatively expensive production method, whereas the production of the outlet guide on the plastic housing part 9 is simple and inexpensive.

The slot 39 also determines the position of the pressure-side pump housing part 34 relative to the pressure-side motor housing part 9 . When the pump is assembled, when the bolts for fixing the pressure-side pump housing part 34 to the cylindrical pump housing part 32 are tightened, the pressure-side motor housing part 34 holds the motor housing part 9 against the motor housing via the return guide vanes 40 . The part 8 is pressed or pressed into the receiving opening 29 of the motor housing part 8 . Furthermore, the motor housing part 9 is thereby pressed against the locking element 27 or the slot tube 24 , so that no additional fixing of the two motor housing parts 8 , 9 is necessary.

When the pump is running, the fluid to be conveyed, in particular coolant, is conveyed through the space between the pump housings 32, 33, 34 and the motor housings 8 and 9 by means of the rotation of the impeller 5 consisting of several impeller blades 44, Flow through the support ribs 31, where part of the vortex has been eliminated due to the function of the support ribs as guide vanes, and further pass through the outlet guide device 42, in which the existing vortex is completely eliminated. Eliminated, the expended energy can thus be converted as completely as possible into pressure energy and thus into axial flow without causing large frictional losses.

Behind impeller 5 , a portion of the fluid flows through bore 45 , which is formed in motor housing part 8 on the suction side. A further part of the fluid also flows behind the impeller 5 to the drive shaft 3 and there flows between the first bearing 11 and the drive shaft 3 , so that the slide bearings present are sufficiently lubricated. The cold fluid in the rotor chamber is thus again conveyed between the drive shaft 3 and the second bearing 15 and through the invisible hole in the blocking element 27 into a space 46 located behind it. This space 46 communicates with the space behind it via a further bore 47 which extends axially through the pressure-side motor housing part 9 . As a result, both lubrication of the bearings 11 , 15 and possible cooling and removal of air volumes that may be present in the rotor chamber are achieved.

This semi-axial pump is characterized in that it can be constructed very small, because the pump can achieve the same delivery with the same power consumption compared to known pumps with a smaller motor size and a higher rotational speed power. This is achieved in particular by the extremely reduced pressure loss in this design, but can also be achieved by a semi-axial design.

Furthermore, pumps of this type can be produced very cheaply, since there are fewer parts for different designs. This also reduces possible errors during assembly. Elimination of additional guide vanes and integration of electrical contacts on the support ribs avoids the use of additional parts and reduces pressure losses. Thereby achieving higher efficiency overall.

Due to the simplicity of the pump housing parts 33 , 34 it is naturally also possible to equip them with flanges arranged on the pressure or suction connection. This makes it possible both to produce a connection directly on the motor housing and to connect several pumps in series in order to increase the delivered fluid volume flow. This is achieved in particular by the fact that a swirl-free flow is produced via the outlet flow guide 42 , so that the impeller 5 of the downstream pump can directly counter the flow without loss of energy. It is therefore also not necessary to construct a pump with a larger motor when double the power is required, but the corresponding number of pumps required are simply connected one after the other due to the same components.

Due to the simplicity of the pump housing part 33 in particular on the suction side, it is also conceivable to construct the pump housing part in one piece with the valve housing part, so that the pump housing part 33 has, for example, a bypass or an integrated thermostat valve receiver. The partial housing of an annular slide valve can also be produced in one piece with the suction-side pump housing part 33 .

It should be pointed out that the exemplary embodiment shown in the drawings relates only to one embodiment of the invention, the structure of which can be varied in various respects without departing from the scope of protection of the claims.

Claims (4)

1. fluid pump that is used for internal-combustion engine has:

One motor, it has a rotor and a stator that is arranged in the motor housing, and wherein, described rotor is arranged on the live axle at least antitorquely,

One active wheel, it is fixed on the described live axle,

At least one guide vane wheel, on the flow direction of the fluid that will carry, this guide vane wheel is arranged on the back of described active wheel, and

One pump casing, this pump casing surround described motor housing, described active wheel and described guide vane wheel, and axial two end part are provided with a pressure tap and a suction adapter opposed to each other on described pump casing,

A plurality of ribs (31), they are set in place in the pump casing of radially outer part (32) and the motor housing of suction side that is positioned at inner radial partly between (8), the motor housing part of this suction side is radially surrounded described motor (1), wherein, the described pump casing part (32) that is positioned at radially outer is Construction integration with the motor housing part (8) and the described ribs (31) of described suction side

It is characterized in that, described ribs (31) moulding in this wise, promptly, constitute guide vane wheel as described fluid pump, and described ribs (31) has such width, that is, an electric contacts can guide to a stator winding (18) by the hole (30) one or more described ribs (31) from an electronic unit.

2. by the described fluid pump that is used for internal-combustion engine of claim 1, it is characterized in that the described pump casing part (32) that is positioned at radially outer is designed to cylindric.

3. by claim 1 or the 2 described fluid pumps that are used for internal-combustion engine, it is characterized in that the housing parts that the pump casing part (33) and that is positioned at the suction side of streamwise expansion is connected on the valve of upstream is designed to one.

4. by the described fluid pump that is used for internal-combustion engine of claim 1, it is characterized in that the motor housing part (8) of described suction side is at the fixed described motor (1) of suction lateral confinement.

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