DE102009003146A1

DE102009003146A1 - Electrically driven liquid pump with a multi-part rotor and manufacturing method for such a rotor

Info

Publication number: DE102009003146A1
Application number: DE102009003146A
Authority: DE
Inventors: Christoph Heier; Bernd Hein; Jerome Thiery
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2009-05-15
Filing date: 2009-05-15
Publication date: 2010-11-18
Also published as: WO2010130522A1

Abstract

A fluid pump (100) with an electric drive (300) is described which comprises a housing (110) and a rotor (200) arranged therein, wherein the rotor (200) has a rotor structure (211) in an electrical section (201). of the electric drive (300) and in a hydraulic section (202) forms a hydraulic impeller structure (221). The rotor (200) is composed of two interconnected components (201, 202). In this case, an electrical component (201) of the rotor (200) comprises the rotor structure (211), while a hydraulic component (202) of the rotor (200) comprises the hydraulic impeller structure (221).

Description

The Invention relates to a liquid pump, for example, a liquid pump for a cooling / heating circuit of a motor vehicle. Such a liquid pump has a housing a rotor disposed therein, in an electrical part of the housing a runner an electronically commutated electric motor and in a hydraulic Part of the housing an impeller structure a hydraulic pumping device forms. According to the invention Rotor formed as a two-component molded part, wherein the the runner forming electrical component of a magnetic material and the impeller structure forming hydraulic component of a liquid and temperature-resistant plastic material are formed. The invention further relates to the two-part rotor and a method of manufacturing such a rotor.
State of the art
electrical liquid pumps are known from various technical applications. Amongst other things come powered by an electronically commutated electric motor liquid pumps as water pumps in cooling and heating circuits used, for example, as a compact additional water pump in the Automotive technology. The housing such a liquid pump includes an electrical housing part with a arranged therein electric drive device and a hydraulic housing part with a pumping device arranged therein. One in both parts of the housing arranged rotor forms both a rotor of the electric drive device as well as an impeller structure the hydraulic pumping device. The rotor is powered by a magnetic interaction of the runner with one in the housing firmly arranged stand package set in rotation. For this purpose, the rotor is magnetically formed, wherein the rotor is made of a plastoferring material by means of an injection molding process generated while the desired Magnetization state of the rotor using a magnetization cage a strong magnetic field is set. The used Plastoferrit material consists of a proportion of a temperature and hydrolysis resistant plastic, for example Polyphenylene sulfide (PPS), a proportion of a hard ferrite powder as well additional Additives. The exact material composition may vary depending on the application vary.
by virtue of the partially conflicting requirements for the material On the hydraulic and electrical side the plastoferrit material proves to be in operation the rotor but already during its production as problematic. For example, one preferably high hard ferrite content in the Plastoferrit material for one high efficiency of the electric motor necessary. On the other hand proves the plastoferrit material with increasing hard ferrite content as increasingly brittle and less elastic. The reduced mechanical load capacity the Plastoferrit material leads to restrictions both in the design of the rotor and in its manufacture. Thus, for example, this is the optimization of the hydraulic wing structures difficult in terms of hydraulic efficiency, in usually with a filigree shape of the wing contours with partially curved wing shapes accompanied. Furthermore, due to the high proportion of hard ferrite in the Plastoferrit material also difficulties in mold filling in Spraying process, whereby different, especially in filigree structures wall thickness can occur within the part contours. Because of the associated Residual stresses, especially at high temperature fluctuations reinforced be, as well as the different Schwindungsverhaltens it can in the operation of the pump easier to crack and thus total failure of the component.
Finally proves a high hard ferrite due to its abrasive effect and the associated increased Tool wear too as unfavorable for the Manufacturing process of the rotor.
outgoing From this prior art, it is an object of the invention with a liquid pump to provide an improved rotor. This task is done by a liquid pump according to claim 1, a rotor according to claim 13 and by a method of manufacturing a rotor according to claim 14 solved.
Disclosure of the invention
According to the invention a liquid pump an electric drive and a housing having disposed therein Rotor, wherein the rotor in an electrical section a Runner of the electric drive and hydraulic in a hydraulic section impeller forms. The rotor is as a two-component molded part with a the runner structure forming electrical component and an impeller structure forming hydraulic component. Due to the two-part construction The rotor simplifies manufacturing, as in each of the two Part injection processes significantly easier molded molded parts produced become. Thus, for example, the production is particularly filigree wing structures the hydraulic side facilitates.
In an advantageous embodiment of the invention, it is provided that the two components have different material properties point. The first component consists of a magnetic material and the second component of a liquid and temperature-resistant plastic material. The use of different materials allows individual optimization of both rotor parts according to their respective task. In particular, a plastic material with special mechanical properties can be used for the hydraulic impeller, with the particularly filigree Flügelradkonturen can be formed. This allows a further optimization of the hydraulic side in terms of efficiency.
A another embodiment provides that the electrical component of the rotor from a Plastoferrit material exists. This material turns out due his sputtering ability as very suitable for creating a magnetic runner. by virtue of the separate production of electrical and hydraulic Side of the rotor it is possible a Plastoferrit material with a higher hard ferrite content use to improve the efficiency of the electric motor.
According to one another embodiment The hydraulic component of the rotor is polyphenylene sulfide. This material is suitable because of its injection molding and its material properties very well as material for the hydraulic rotor side. This can be desired Material properties of this plastic, such as his Sliding property or stability, especially easy by adding suitable additives even further improve.
A another embodiment provides that the two components using connection structures form-fitting interconnected with at least one connection structure as Driver for torque transmission between the components. Due to the positive connection will be a particularly strong connection between the two parts reached. With the help of the driver can also be a simple torque transmission will be realized. Finally leave Such connection structures are particularly easy to use realize used spraying process.
According to one another embodiment is the connection structure as a radially extending guide with a T-shaped Cross section formed. This cross-sectional shape allows a safe positive Connection between the parts. The axial alignment of the connection structure allows the Function as driver for transmission the torque of the rotor on the impeller.
A another embodiment provides that the bearing of the rotor in the housing using a plain bearing takes place, which is a a housing pin receiving axial bore in the hydraulic component. By selecting a suitable plastic material, the plain bearing without an additional Carbon bushing can be realized, reducing the manufacture of the rotor is simplified. Furthermore, it is provided that the axial bore at least partially within one in the electrical section of the rotor protruding bearing pin of the hydraulic component is trained. As a result, the storage distance is extended, which with a quiet and wear-free Storage is associated.
According to one another embodiment contains the material of the hydraulic component an additive that improves the sliding properties of the plain bearing. By a suitable Selection of additives can reduce the wear of the plain bearing and thus a maintenance-free sliding bearing can be realized. Provided, as in another embodiment the case, as an additive teflon, carbon fibers and / or carbon spheres used, improve the sliding properties of the bearing especially clear. By using carbon fiber as an additive Furthermore, an improvement in the mechanical strength of the hydraulic Part of the rotor achieved. In addition, the added carbon fibers can the common used to improve the mechanical properties of the rotor Replace glass fibers.
In a further embodiment For example, the hydraulic component includes a shielding member that extends bund shape extends around the entire circumference of the rotor. The shielding element Prevents magnetic molding sand from the coolant in the electrical Pump part passes and there is abrasive.
A another embodiment provides that the electrical component is essentially the shape a hollow cylinder. This simple design is simplifies the manufacturing process of the molded part. Due to the The magnetization is also particularly simple tool of the runner enormously relieved.
According to the invention, in the production of a rotor for the liquid pump according to the invention, first a first component of the rotor is produced from a first material. Subsequently, the second component of the rotor is produced by injecting a second material to the first component. It is advantageous to provide the first component with at least one connecting structure, which is encapsulated in the production of the second component and thereby a positive connection between the two components he testifies.
According to one first embodiment of the manufacturing process becomes the first component in a first Spray process produced using a first injection molding tool and subsequently inserted in a second injection mold. The second component becomes in a second injection process using the second injection mold generated. The use of separate injection molds allows an individual Optimization of the manufacturing process for each of the two parts.
Become however, as in another embodiment of the manufacturing process provided the two components in two consecutive Spraying processes using a common injection tool generated, wherein the first component in a pre-injection process in a first part of the spray tool and the second component in a finish-spraying process in one second part of the injection mold is produced, the manufacturing process be rationalized.
in the Below, the invention will be explained in more detail with reference to figures. It demonstrate:
1 a liquid pump according to the prior art with a one-piece Plastoferrit rotor;
2 a liquid pump according to the invention with a rotor designed as a two-component injection molded part;
3 a cross-sectional view of the rotor according to the invention with an electrical part formed from Plastoferrit and formed of a plastic material hydraulic part;
4 a perspective cross-sectional view of the rotor according to the invention 3 ;
5 an exploded view of the rotor according to the invention;
6 a detailed representations of the Plastoferrit rotor from the 5 ;
7 another perspective view of the Plastoferrit rotor from the 5 with four connection structures created by means of advanced technology;
8th a perspective view of the hydraulic rotor part 5 with a trunnion and four connecting structures.
The 1 shows a means of an electronically commutated electric motor 300 driven liquid pump 100 according to the prior art. Here is the electric motor 300 together with the hydraulic pumping device 400 in a housing 110 accommodated. The integrally formed by a injection molding process of a plastic ferrite material rotor 200 forms a runner in its electrical section 211 of the electric motor 300 and in its hydraulic section, an impeller 221 the hydraulic pumping device 400 , One between the two sections 210 . 220 of the rotor 200 angeordne ter neutral rotor section 240 acts as a shielding, which separates the electrical from the hydraulic pump side.
The rotor 200 is by means of a sliding bearing 230 on a fixed housing pin 103 rotatably mounted. For this purpose, the rotor body 200 a along its axis of rotation extending axial bore for receiving the housing pin 103 on. The plain bearing is by a between rotor body 200 and housing pin 103 pickled carbon bush 233 realized.
The controlled by a special electronics stator 310 consists of several in the electrical housing part 111 along the circumference of the runner 211 arranged electric coils. These electric coils generate during operation of the electric motor 300 a rotating magnetic field through which the rotor forming the magnetic part of the EC motor 211 is set in rotation. For this purpose, the rotor 200 molded from a Plastoferrit material and the electrical rotor section 201 magnetized during the injection process in a magnetization cage. After curing of the plastoferrite material, the hard ferrite particles oriented in the external magnetic field maintain their alignment and thus produce the desired magnetization of the rotor 211 ,
The shielding element 240 serves to protect the electrical side against the ingress of molding sand from the hydraulic fluid. As a sealing element serves a labyrinth area, which by a on the runner facing side of the shield 240 arranged circumferential groove 241 and one in the groove 241 correspondingly engaging circumferential structure of the housing 110 is formed.
The 2 shows a liquid pump according to the invention 100 with a rotor formed as a two-component injection molded part 200 , This liquid pump 100 essentially has a to that of the 1 known liquid pump analog construction. In contrast to the known rotor from the 1 consists in the two-component rotor according to the invention 200 however, only the rotor made of a Plastoferrit material. Of the hydraulic rotor section 202 that with the hydraulic rotor section 201 integrally formed shielding 240 and also with the hydraulic rotor section 201 integral bearing journals 232 On the other hand, they are made of a plastic material. As a material is basically any sprayable plastic with a high temperature and hydrolysis resistance, such as a polyphenylene sulfide (PPS). It is particularly cost-effective to use a plastic material from which already other parts of the housing 110 consist. Furthermore, special plastics can be used which have optimized properties with respect to the hydraulic application.
Unlike the one from the 1 known liquid pump is no additional coal bushing in the embodiment of the invention 233 for storage of the rotor 200 on the housing pin 103 intended. This is made possible in particular by eliminating the highly abrasive hard ferrite. To improve its sliding properties, the plastic material may further comprise an additive, such. As Teflon, carbon fibers or carbon spheres are added.
The 3 shows the rotor according to the invention 200 from the 2 in a sectional view. The rotor 200 consists essentially of two components 201 . 202 , which are formed as two separate, but interconnected molded parts. In contrast to the formed in the form of a simple ring electrical component 201 , that is the hydraulic rotor section 220 , the shielding element 240 and the journal 232 comprehensive hydraulic component 202 formed as a complex molded part. In this case, the hydraulic rotor section 220 through an impeller 221 formed, the more about a slightly tapered impeller axis 223 arranged wing structures 222 includes. The wing structures 222 of which in the 3 only two are shown, adjacent to a shielding element 240 forming plate-shaped area. The number, the distribution and the shape of the here formed as a simple blades with a polygonal profile wing structures 222 can vary depending on the application. Due to the lack of hard ferrite powder, the plastic material used has significantly improved mechanical properties compared to the plastoferror material used for the conventional rotor. The design of the wing structures is therefore no longer subject to the restrictions imposed by a high hard ferrite content. Thus, an optimized especially on the hydraulic efficiency shaping of the impeller is 221 with very delicate and curved wing structures 222 without problems possible.
The from the Flügelradachse 223 , a core portion of the shielding member 240 and the journal 232 formed hub has a central bore 231 for receiving the housing pin. To comply with the installation dimensions of the conventional rotor with inserted carbon bushing and thus the installation in a conventional housing 110 is possible with the rotor shown here 200 at each of the front end of the hub in each case a paragraph 234 intended.
In order to operate the rotor 200 also to transmit high torques between the hydraulic and the electric rotor part, is a firm connection between the two components 201 . 202 intended. This is preferably achieved by means of a positive connection. For this purpose, for example, one or more connection structures 250 on a first component produced in a first injection process 201 . 202 are provided, which are overmolded in the course of the second injection process by the material of the second component. The connection structures created in this way 250 then serve simultaneously as a driver.
The in the 4 shown perspective view of the rotor according to the invention 200 illustrates the special mechanical connection between the two components 201 . 202 by means of several T-shaped connecting structures 250 , The on the hydraulic component 202 molded connection structures 250 are arranged along the interface between the two components. They engage in corresponding recesses 260 of the runner 211 representing hollow cylinder. As a result, a positive connection between the two components is realized.
To clarify the structure of the two-component rotor 200 show the 5 an exploded view of the rotor according to the invention 200 , In this case, a total of four formed as a radially extending T-shaped guides connecting structures 250 evenly arranged along the interface between the two components. The complementary connection structures 260 of the electrical counterpart 211 are as corresponding recesses for receiving the connection structures 250 educated.
The manufacture of the rotor 200 preferably by means of a two-part injection molding process. Both components can do this 201 . 202 be generated in different parts of a common injection mold. In this case, first one of the two components 201 . 202 generated in the context of a pre-injection by injecting the corresponding material in a first tool part. Subsequently, the second component is in the context of a final injection by A injecting the corresponding material into a second tool part.
Alternatively, the preparation of the two components 201 . 202 also by using two different injection tools. In this case, in a first injection process by injecting the corresponding material into a first injection molding tool first, the first component 201 . 202 prefabricated as an intermediate and then placed in a second injection mold. Here, in a subsequent second injection process, the second component is injected by injecting the appropriate material to the prefabricated first component.
Which of the two components 201 . 202 generated in the first of the two Teilspritzprozesse and which component is then injected subsequently to the already existing, depends primarily on the particular application. For example, it is advantageous to use the plastoferrite rotor 211 prefabricated as an intermediate product by means of a separate injection mold equipped with a magnetic cage and the rotor 200 then by in a second injection mold by injection molding of the hydraulic component 202 finish. Thus, the magnetization cage and thus the magnetization of the rotor can be optimized.
The 6 and 7 show two different perspective views of the runner 211 forming electrical component 201 , It can be seen that the plastoferrite rotor 211 is formed substantially as a simple molded part in the form of a hollow cylinder. The connection points 260 are preferably formed as recesses in the hydraulic side facing the end face of the hollow cylinder. Such a recess 260 has one of the shape of the associated connection structure 250 the hydraulic component 202 corresponding geometry. In the present embodiment, the recesses 260 thus formed as T-shaped grooves. Basically, the shape of the connection structures 250 . 260 and their number and distribution vary along the circumference of the hollow cylinder depending on the application.
The 8th finally shows a perspective view of the hydraulic component 202 , The injection molded part, which is produced in one piece from a liquid and temperature-resistant plastic material 202 includes a hydraulic section 220 forming impeller 221 with a total of four around a central impeller axis 223 arranged wing structures 222 , a the shielding element 240 forming plate-shaped area with one of the electrical rotor side facing circumferential groove 241 and four interconnection structures uniformly arranged along the circumference 250 and a journal 232 ,
at the objects disclosed in the foregoing description, claims and drawings these are exemplary embodiments the invention. A person skilled in the art therefore recognizes that the invention is not only to these embodiments limited is. It can be all of the inventive aspects disclosed herein individually as well as also in combination with each other for the realization of the invention prove relevant. In particular, the special design the parts, such as the type of connection between the Components shown here by way of example only.

Claims

Liquid pump ( 100 ) with an electric drive ( 300 ) comprising a housing ( 110 ) and a rotor disposed therein ( 200 ), wherein the rotor ( 200 ) in an electrical section ( 210 ) a runner structure ( 211 ) of the electric drive ( 300 ) and in a hydraulic section ( 220 ) an impeller structure ( 221 ), characterized in that the rotor ( 200 ) as a two-component molded part comprising a rotor structure ( 211 ) forming electrical component ( 201 ) and one the impeller structure ( 221 ) forming hydraulic component ( 202 ) is trained.
Liquid pump ( 100 ) according to claim 1, characterized in that the two components ( 201 . 202 ) have different material properties, wherein the electrical component ( 201 ) consists of a magnetic material, and wherein the hydraulic component ( 202 ) consists of a fluid and temperature resistant plastic material.
Liquid pump ( 100 ) according to claim 2, characterized in that as the material of the electrical component ( 201 ) of the rotor ( 200 ) a Plastoferrit serves.
Liquid pump ( 100 ) according to claim 2 or 3, characterized in that the material for the hydraulic component ( 202 ) of the rotor ( 200 ) comprises a polyphenylene sulfide.
Liquid pump ( 100 ) according to one of the preceding claims, characterized in that the two components ( 201 . 202 ) using connection structures ( 250 . 260 ) are positively connected with each other, wherein at least one connection structure ( 250 ) as a driver for Drehmo transmission between the components ( 201 . 202 ) serves.
Liquid pump ( 100 ) according to claim 5, characterized in that the connection structure ( 250 ) is formed as a radially extending guide with a T-shaped cross-section.
Liquid pump ( 100 ) according to one of the preceding claims, characterized in that the rotor ( 200 ) by means of a sliding bearing ( 230 ), one in the hydraulic component ( 202 ) and a housing pin ( 113 ) receiving axial bore ( 231 ), in the housing ( 110 ) is stored.
Liquid pump ( 100 ) according to claim 7, characterized in that the axial bore ( 231 ) at least partially within one in the electrical section ( 210 ) of the rotor extending journal ( 232 ) of the hydraulic component ( 202 ) is trained.
Liquid pump ( 100 ) according to claim 7 or 8, characterized in that the material of the hydraulic component ( 202 ) contains an additive which reduces the sliding properties of the sliding bearing ( 230 ) improved.
Liquid pump ( 100 ) according to claim 9, characterized in that Teflon, carbon fibers and / or carbon spheres are used as additive.
Liquid pump ( 100 ) according to one of the preceding claims, characterized in that the rotor ( 200 ) a shielding element ( 240 ), which forms part of the hydraulic component ( 202 ) in a bundle around the entire circumference of the rotor ( 200 ).
Liquid pump ( 100 ) according to one of the preceding claims, characterized in that the electrical component ( 201 ) has substantially the shape of a hollow cylinder.
Rotor ( 200 ) for a liquid pump ( 100 ) according to one of claims 1 to 12, wherein the rotor ( 200 ) in an electrical section ( 210 ) a runner structure ( 211 ) and in a hydraulic section ( 220 ) an impeller structure ( 221 ), characterized in that the rotor ( 200 ) as a two-component molded part comprising a rotor structure ( 211 ) forming electrical component ( 201 ) and one the impeller structure ( 221 ) forming hydraulic component ( 202 ) is trained.
Method for producing a rotor ( 200 ) having the features of claim 13, wherein the rotor ( 200 ) is produced by means of a two-part injection molding process as a two-component injection molding, comprising the method steps: providing a first component consisting of a first material ( 201 . 202 ) of the rotor ( 200 ), and - generating a second component ( 202 . 201 ) of the rotor ( 200 ) by injection of a second material to the first component ( 201 . 202 )
Method for producing a rotor ( 200 ) according to claim 14, wherein the first component ( 201 . 202 ) at least one connection structure ( 250 . 260 ), which during injection of the second component ( 202 . 201 ) is extrusion-coated by its second material in such a way that a form-locking connection between the two components ( 201 . 202 ) is produced.
A method according to claim 15, wherein the manufacture of the rotor ( 200 ) by means of two injection molds, comprising the steps: - performing a first injection process to produce the first component ( 201 . 202 ) using a first injection molding tool, - inserting the first component ( 201 . 202 ) in a second injection mold, and - performing a second injection process for producing the second component ( 202 . 201 ) using the second injection molding tool.
A method according to claim 16, wherein the manufacture of the rotor ( 200 ) by means of a single injection molding tool, comprising the steps of: - performing a first injection process in a first part of the injection molding tool to produce the first component ( 201 . 202 ), - carrying out a second injection process in a second part of the injection molding tool to produce the second component ( 202 . 201 ).