EP2473740A1

EP2473740A1 - Two-stage centrifugal pump

Info

Publication number: EP2473740A1
Application number: EP10734096A
Authority: EP
Inventors: Bernd Hein; Jerome Thiery; Christoph Heier
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2009-09-01
Filing date: 2010-07-13
Publication date: 2012-07-11
Also published as: IN2012DN01413A; KR20120061854A; WO2011026678A1; US20120219411A1; JP5599463B2; DE102009029069A1; JP2013503997A; CN102483067A

Abstract

The invention relates to a centrifugal pump (100), in particular for a coolant in a motor vehicle, comprising a first centrifugal pump stage (102) having a first pump housing (108), and a first impeller (110) rotatably mounted therein, and to a drive device (106) for coaxially driving the first impeller. A second centrifugal pump stage (104) has a second pump housing (114) and a second impeller (116) rotatably mounted therein and an intermediate housing (120) is located between the first and the second pump housing (108, 114) for diverting a fluid flow dispersed by the first impeller to an inlet region of the second impeller.

Description

description

title

Two-stage centrifugal pump

The invention relates to a centrifugal pump. In particular, the invention relates to a two-stage centrifugal pump for a coolant in a motor vehicle.

State of the art

Single-stage centrifugal pumps, for example for conveying a coolant, are known in various variations. For example, a single-stage centrifugal pump is shown in EP 1850448 A1, in which a rotor of an electric motor driving the centrifugal pump is integrated with an impeller of the centrifugal pump.

In complex environments, such as in a motor vehicle, varying demands are placed on a centrifugal pump. Modern motor vehicles include, for example, various additional cooling circuits, such as intercooler or for cooling of electronic modules that may require a higher pressure build-up with the same or lower delivery volume compared to a centrifugal pump used in a main cooling circuit. A basically suitable for these requirements single-stage centrifugal pump with higher performance than the main centrifugal pump is usually much more expensive and has a larger outer diameter, so that they can not be readily mounted as the main centrifugal pump in the vehicle.

It is therefore an object of the invention to provide a centrifugal pump which has compact external dimensions at high pressure build-up and is easy to assemble. The problem is solved by a centrifugal pump with the features of claim 1. Claim 9 mentions a method for mounting such a centrifugal pump; Subclaims indicate possible or advantageous embodiments.

Disclosure of the invention

According to a first aspect of the invention, a centrifugal pump, in particular for a coolant in a motor vehicle, comprises a first centrifugal pump stage with a first pump housing and a first impeller rotatably disposed therein, a drive means for coaxial drive of the first impeller, a second centrifugal pump stage with a second A pump housing and a second impeller rotatably disposed therein and an intermediate housing disposed between the first and the second pump housing for deflecting a liquid flow discharged from the first impeller to an inlet region of the second impeller.

By using a two-stage centrifugal pump, the liquid to be delivered can first be conveyed in the first centrifugal pump stage and then placed under increased pressure in the second centrifugal pump stage. Thus, an increased pressure increase compared to a single-stage centrifugal pump can be realized with a constant outer diameter, so that an existing installation space can be used unchanged and optionally fasteners such as a rubber boot can be adopted unchanged. The intermediate housing may comprise deflecting elements which deflect the fluid flow from an off-axis outflow region of the first impeller to a near-axis inlet region of the second impeller. The deflecting elements can, for example, run crescent-shaped onto a common axis of rotation of both impellers.

The intermediate housing can be materially connected to the second pump housing. The material fit allows a corrosion-resistant and thus robust and long-lasting connection. The connection can be connected, for example, by means of gluing, laser welding, ultrasonic welding, hot stamping or another known type of connection. In a further embodiment, the intermediate housing can also be connected to the first pump housing be connected. Furthermore, the intermediate housing can also be connected to one of the two pump housings by only a force fit by means of any known technique. The connection creates a unit that can be handled separately, which may be advantageous when mounting the centrifugal pump.

The pump housings of the centrifugal pump can adjoin one another and the intermediate housing can be accommodated in the first pump housing. The intermediate housing can occupy a space in the first pump housing, which is provided in a similar manner in the second pump housing, and is filled there for example by a portion of the adjacent drive means. Thus, the two pump housings may have similar or partially internal geometries, which may reduce manufacturing costs.

The drive device may comprise a bearing pin and a rotor with a drive sleeve rotatably mounted on the bearing pin, with which the second impeller is connected in a torque-locking manner. The bearing pin can be arranged rotationally fixed to a stator of the drive device. In this way, the second impeller not integrated with the rotor must be made, but can be connected torque-locked to the rotor only in the context of a pre-assembly or final assembly. In addition, the first impeller may be rotatably mounted on the bearing pin, so that an axial alignment of the drive means and both impellers is ensured by means of the bearing pin.

In this case, the first impeller may be connected by means of a driving geometry torque-locking with the drive sleeve. The entrainment geometry may include, for example, interlocking crown-shaped contours on adjacent end faces of the drive sleeve and the first impeller. The entrainment geometry can be shaped so that the first impeller can be brought into engagement with the drive sleeve without effort, so that an assembly process does not affect the precision of the arrangement.

The first impeller may also be connected by means of a driving geometry torque-locking manner with the second impeller. The first centrifugal pump stage, the second centrifugal pump stage and the drive device can be arranged axially one behind the other, and the first pump housing can comprise an intake manifold leading to a near-axis inlet region of the first impeller. As a result, in particular, a section of the two-stage centrifugal pump facing away from the drive unit can be shaped as in the single-stage centrifugal pump, so that exchangeability is facilitated.

A gap area between the rotating first impeller and the first pump housing may correspond to a gap area between the rotating second impeller and the second pump housing such that the second impeller is insertable into the first pump housing instead of the first impeller to form a single stage centrifugal pump. When manufacturing centrifugal pumps on a partially or fully automated production line, it is possible to switch between a production of single-stage centrifugal pumps and two-stage centrifugal pumps with a manageable conversion effort.

According to a second aspect of the invention, a method of mounting the above-described two-stage centrifugal pump comprises steps of pushing the second impeller onto the drive sleeve of the rotor, placing the second pump housing with the intermediate housing on the drive means, sliding the first impeller onto the bearing pin, and Placing the first pump housing on the second pump housing. Due to the selected structure of the centrifugal pump their final assembly includes only a few, with low requirements, such as precision, effort and speed, feasible steps.

The method may also include the preceding step of connecting the intermediate housing to the second pump housing. In this way, a separately manageable unit is created, which further simplifies the method of mounting. Optionally, the second impeller with the drive sleeve and the rotor of the drive device can also be assembled beforehand to form a unit that can be handled separately. The invention will now be described with reference to the accompanying drawings, in which:

Figure 1 shows a longitudinal section through a two-stage centrifugal pump;

Figure 2 is an isometric view of the second pump housing with the intermediate housing of Figure 1;

Figure 3a shows a torque-locking connection of the first with the second impeller in Figure 1;

Figure 3b shows a variation of the connection of Figure 3a; and

FIG. 4 illustrates a method of mounting the centrifugal pump of FIG. Identical or corresponding elements carry the same reference numerals in all figures.

FIG. 1 shows a longitudinal section through the centrifugal pump 100. The centrifugal pump 100 comprises a first pump stage 102, a second pump stage 104 and an electric motor 106 as a drive device. The first pump stage 102 comprises a first pump housing 108 and a first impeller 1 10, between which a first gap region 1 12 is formed. The second pump stage 104 includes a second pump housing 1 14 and a second impeller 1 16, between which a second gap region 1 18 is formed. In an area between the first pump stage 102 and the second pump stage 104, an intermediate housing 120 is arranged. The first pump housing 108 abuts the second pump housing 1 14 and is sealed by means of an O-ring 122 against this. The second pump housing 1 14 abuts the electric motor 106 and is sealed in a corresponding manner by means of an O-ring 124 with respect to this.

The electric motor 106 includes a stator 128, a rotor 130 with permanent magnets 132, a drive sleeve 134, a bearing pin 136, an electrical control device 138 and a housing 140. Bolt channels 142 pass through the first pump housing 108, the second pump housing 14 and the housing 140 the electric motor 106 to receive respective bolts (not shown) which hold the centrifugal pump 100 together.

Indicated by arrows is a flow direction of a liquid through the centrifugal pump 100. The liquid enters the bottom through an intake manifold 144 formed on the first pump housing 108 and arrives at an axle In operation, the impeller 1 10 rotates about the bearing pin 136, so that the liquid is accelerated in the radial direction and is discharged to the outside. On its left side, the intermediate housing 120 has a recess through which the flowed liquid 5 rises upwards and flows along deflecting elements 146 of the intermediate housing 120 onto the bearing pin 136. From there, the liquid continues to move upwards into an inlet region of the second impeller 1 16 close to the axis. In operation, this also rotates about the bearing pin 136, so that the liquid is accelerated again in the radial direction and is discharged to the outside 10. The second pump housing 1 14 has a larger inner diameter than the outer diameter of the second impeller 1 16, so that a radial gap is formed, along which the flowed liquid flows in the direction of a formed on the circumference of the second pump housing 1 14 pressure port 148 through which the Finally, liquid leaves the circular pump 100.

At its upper end, the bearing pin 136 is rotatably received at a portion of the stator 128, for example by means of a press or fitting connection. Rotatably mounted on the bearing pin 136 is the drive sleeve

20 134, the torsionally stable with the permanent magnet 132 and the second impeller

1 16 is connected. For attachment of the permanent magnet 132 to the drive sleeve 134 further components may be used, for example, a magnetic carrier, not shown. This may include the permanent magnets 132 liquid-tight. Apart from that, the rotor 130 is to be supported by the

25 rinsed liquid. A position of the drive sleeve 134 on the bearing pin 136 upwards is limited by contact of the drive sleeve 134 on the stator 128.

At its lower end, the bearing pin 136 is arranged in a receptacle formed on the first pump housing 108. The bearing pin 136 is chamfered at its lower end to facilitate its insertion into the receptacle. Above the receptacle, the first impeller 1 10 is rotatably disposed about the bearing pin 136. For this purpose, a bearing bush 150 is disposed between the first impeller 1 10 and the bearing pin 136, which is rotationally stable connected to the first wing gel wheel 1 10, for example by shrinking, pressing, gluing or spraying. A position of the first impeller 1 10 on the bearing pin 136 down is limited by concern of the first impeller 1 10 on the first pump housing 108. A device for transmitting torque from the second impeller 1 16 or the drive sleeve 134 to the first impeller 1 10, which also defines a position of the first impeller 1 10 upwards and the drive sleeve 134 down, is not shown in Figure 1 and will be described in detail below with reference to Figs. 3a and 3b.

Figure 2 shows an isometric view of the intermediate housing 120. In the middle, the intermediate housing 120 has a round center recess 205, in the front region a lateral recess 210 can be seen, by the liquid from the bottom of the intermediate housing 120 to the deflecting elements 146 in the region of the top of the intermediate housing 120 can flow. On an upper surface of the intermediate housing 120 five sickle-shaped deflecting elements 146 are arranged to extend from a radius of the intermediate housing 120 on the central center recess 205. The radius is selected so that a radially outer region of the upper side of the intermediate housing 120 can be surrounded by liquid without hindrance.

Each deflection element 146 has on its upper side a pin 220 for engagement in and optional bonding with corresponding recesses in the second pump housing 14 1. In another embodiment, the pins 220 are missing and the intermediate housing 120 is glued flat in the region of the deflecting elements 146 with the second pump housing 14. By connecting the intermediate housing 120 with the second pump housing 1 14, a separately manageable unit is formed.

Figure 3a shows a device, not shown in Figure 1 for transmitting torque between the first impeller 1 10 and the second impeller 1 16. The first impeller 1 10 is rotatably connected to the bearing bush 150, which is freely rotatably mounted on the bearing pin 136. Unlike the

Representation in Figure 1, the bushing 150 passes through the first impeller only in a lower portion.

The second impeller 1 16 is rotatably connected to the drive sleeve 134 which is freely rotatably mounted on the bearing pin 136. In the area of the bearing bolt

136, the second impeller is at its lower end pointing down long shaped, so that its lower end face adjacent to the upper end face of the first impeller 1 10. Thereby, a distance of the vanes 1 10 and 1 16 is limited to the bearing pin 136. In the region of the abutting end faces of the vanes 1 10 and 1 16 is a crown profile 152, of which on the right side of the bearing pin 136 a point is visible. With the help of the crown profile 152, the vanes 1 10 and 1 16 torque-stable interconnected. The engaging flanks of the crown profile 152 may, for example, extend in a rectangular, trapezoidal or wavy manner about the bearing pin 136 and one or more tines may be encompassed by the crown profile 152. Adjacent edges of the teeth can run parallel or obliquely to each other, so that a torque is preferably transmitted in one direction of rotation. As a result, an assembly of the vanes 1 10 and 1 16 each other can be facilitated. In a further embodiment, a driving pin (not shown) parallel to the bearing pin 136 can also engage in corresponding recesses of the impellers 1 10 and 16 and connect them to each other in a torque-locking manner.

FIG. 3b shows an alternative embodiment of the device shown in FIG. 3a for use in the centrifugal pump 100 from FIG. The device substantially corresponds to that of Figure 3a, with the difference that not the lower end face of the second impeller 1 16, but the lower end face of the drive sleeve 134 with the upper end face of the first impeller 1 10 via the crown profile 152 is engaged.

FIG. 4 shows a method 400 with steps 405 to 465 for mounting the centrifugal pump 100 from FIG. 1. In step 405, the method 400 is in the start state. In the first step 410, the stator 128 is oriented together with the housing 140 and the control device 138 so that the bearing pin 136 faces upward. Subsequently, in step 415, the rotor 130 with the permanent magnets 132 is pushed onto the drive sleeve 134. Thereafter, in step 420, the second impeller 1 16 pushed onto the drive sleeve 134. The thus created subassembly is pushed in the following step 425 on the bearing pin 136 and is located on the stator 128 of the electric motor 106. Thereafter, the second O-ring 124 is inserted into the second pump housing 1 14 and then in step 435, the second pump housing 1 14 placed on the electric motor 106. Now, in step 440, the first impeller 1 10 is pushed onto the bearing pin 136. Then, in step 445, the first O-ring 122 is inserted into the first pump housing 108 and the first pump housing 108 is placed on the second pump housing 14 in step 450. In the following steps 455 and 460, bolts are inserted and tightened in the bolt channels 142, such as by bolting or riveting. Thereafter, the process is in the final state 465.

By means of the method 400, the centrifugal pump 100 can be mounted efficiently, whereby only in the separately executable steps 415 and 420 and in the final step 460 greater forces must be expended. In intermediate stages between method steps 405 to 465 of method 400, already juxtaposed elements of pump 100 are held together by gravity, so that no holding or clamping devices are required. By using a crown profile 152, the bearing of the movable components 1 10, 150, 1 16, 134 of the centrifugal pump 100 along the bearing pin 136 is defined and at the same time a torque flow to the first impeller 1 10 is made without mechanical elements of the centrifugal pump 100 by the assembly process strain.

Claims

claims

1 . Centrifugal pump (100), in particular for a coolant in a motor vehicle, comprising:

- A first centrifugal pump stage (102) having a first pump housing (108) and a rotatably disposed therein first impeller (1 10);

- A drive means (106) for coaxial drive of the first impeller (1 10);

marked by

- A second centrifugal pump stage (104) having a second pump housing (1 14) and a second impeller rotatably disposed therein (1 16);

- Between the first and the second pump housing (1 14) provided intermediate housing (120) for deflecting a flow of the first impeller (1 10) flowed to an inlet region of the second impeller (1 16).

Second centrifugal pump (100) according to claim 1, characterized in that the intermediate housing (120) is materially connected to the second pump housing (1 14).

3. Centrifugal pump (100) according to claim 1 or 2, characterized in that the pump housing (108, 1 14) adjoin one another and that the intermediate housing (120) in the first pump housing (108) is accommodated.

4. Centrifugal pump (100) according to any one of the preceding claims, characterized in that the drive device (106) comprises a bearing pin (136) and a rotor (130) with a rotatably mounted on the bearing pin (136) drive sleeve (134), with the the second impeller (1 16) is connected torque-locking.

5. Centrifugal pump (100) according to claim 4, characterized in that the first impeller (1 10) by means of a driving geometry (152) is torque-connected to the drive sleeve.

Centrifugal pump (100) according to one of the preceding claims, characterized in that the first impeller (1 10) by means of a driving geometry (152) torque-locking manner with the second impeller (1 16) is connected.

7. Centrifugal pump (100) according to any one of the preceding claims, characterized in that the first centrifugal pump stage (102), the second centrifugal pump stage (104) and the drive means (106) are arranged one behind the other and that the first pump housing (108) one to a near-axis Inlet portion of the first impeller (1 10) leading intake manifold (108) includes.

8. Centrifugal pump (100) according to any one of the preceding claims, characterized in that a gap region (1 12) between the rotating first impeller (1 10) and the first pump housing (108) a Spaltbe- rich (1 18) between the rotating second Impeller (1 16) and the second pump housing (1 14) corresponds, so that the second impeller (1 16) instead of the first impeller (1 10) in the first pump housing (108) can be used to form a single-stage centrifugal pump.

9. A method for mounting the centrifugal pump (100) according to claim 4, characterized by the following steps:

- Sliding the second impeller (1 16) on the drive sleeve (134) of the rotor;

- Place the second pump housing (1 14) with the Zwischengehäu- se (120) on the drive means (106);

- Sliding the first impeller (1 10) on the bearing pin (136); and

- Place the first pump housing (108) on the second pump housing (1 14). A method according to claim 9, characterized by the preceding step of connecting the intermediate housing (120) to the second housing (1 14).