An electronics unit for a centrifugal pump, a centrifugal pump and a method for assembling an electronics unit for a centrifugal pump

Abstract

Disclosed and claimed is an electronics unit for a centrifugal pump. A connector is attached to the electronics unit and automatically connects the electronics unit to an electric motor when the electronics unit is mounted to the electric motor in a translational movement along a translatory axis. A plate-shaped guide means aligns the connector with a contact pin of the electric motor. Contact means establish an electric connection between the connector and the contact pin. The plate-shaped guide means extends perpendicular to the translatory axis in a transversal plane and comprises an alignment opening for receiving a contact pin extending parallel to the translatory axis. The contact means comprises three or more elastic contact elements. Each contact element comprises a contact surface which is in direct contact with the contact pin and is biased towards the pin area. Further, an exemplary embodiment of centrifugal pump is disclosed and claimed.

Description

[0001] Applicant: GRUNDFOS HOLDING A / S

[0002] Title: An electronics unit for a centrifugal pump, a centrifugal pump and a method for assembling an electronics unit for a centrifugal pump

[0003] Our Ref.: GP 3806 WO

[0004] Description

[0005]

[0001] The present invention is directed to an electronics unit for a centrifugal pump with a connector for electrically connecting the electronics unit to an electric motor of the centrifugal pump. The invention is further directed to a centrifugal pump comprising an electronics unit and an electric motor as well as a method for assembling an electronics unit for a centrifugal pump.

[0006]

[0002] Centrifugal pumps which are driven by electric motors are used, for example, as heating circulation pumps. The centrifugal pumps comprise an impeller housing surrounding an impeller which pressurizes the pump fluid. The impeller is driven by the electric motor which is surrounded by a motor housing. The electric motor comprises a rotor which is attached to a drive shaft of the impeller and which may be located in a rotor can, i.e., the electric motor may be a wet-running electric motor. The rotor is surrounded by a stator. The stator is electrically powered, and its rotation is controlled by an electronics unit that is attached to the electric motor. The electronics unit may, for example, control the speed of the electric motor, provide a display with information for a user, and provide external electrical contacts.

[0007]

[0003] Commonly, the electronics unit is attached or mounted to the electric motor by a translational movement, i.e., the electronics unit moves along a translator / axis when being mounted to the electric motor without additional rotations. While the electronics unit is mounted to the electric motor, electric connections need to be established. For example, electric connections are required fordriving the coils of the stator and to ensure that a metal housing of the electric motor is connected to Earth. Multiple electric connectors are therefore provided on the electronics unit that automatically engage mating contacts at the electric motor. However, if the electronics unit and the electric motor are not correctly aligned during the mounting of the electronics unit, the electric connectors may be damaged and no or at least no reliable connection is established. Determining if the connectors where damaged can only be done during electronic unit testing. The electric connections are located inside the motor housing and the electronics unit and cannot be visually inspected. Further, since the connectors are oftentimes molded into parts of the electronics unit, if a connector is damaged the entire part may have to be discarded.

[0008]

[0004] In view of the above it is an object of the present invention to provide an improved electronics unit for a centrifugal pump with a connector. A further object of the present invention is to provide an improved centrifugal pump with an electronics unit and an electric motor as well as a method for assembling an electronics unit for a centrifugal pump.

[0009]

[0005] The object is solved by an electronics unit, a centrifugal pump and a method for assembling an electronics unit according to the corresponding independent claims. Preferred embodiments of the electronics unit and the method for assembling an electronics unit are the subject matter of the dependent claims.

[0010]

[0006] In a first aspect, the invention is directed to an electronics unit for a centrifugal pump with a connector for electrically connecting the electronics unit to an electric motor of the centrifugal pump. The connector is configured to be mounted in the electronics unit. Further, the connector is configured to automatically establish an electric connection between the electronics unit and the electric motor when the electronics unit is mounted to the electric motor by means of a translational movement along a translator / axis. The connector comprises a plateshaped guide means for aligning the connector with a contact pin formed at the electric motor and a contact means for establishing an electric connection between the connector and the contact pin. The plate-shaped guide means extends perpendicular to the translator / axis in a transversal plane and comprises an alignment opening for receiving a contact pin extending parallel to the translator / axis. The contact means comprises three or more elastic contact elements surrounding a pin area for receiving the contact pin. Each of the contact elements comprises a contact surface which is in direct contact with the contact pin when the electronics unit has been mounted to the electric motor. Each of the contact elements is further biased towards the pin area when the electronics unit has been attached to the electric motor. The pin area is aligned with the alignment opening on an axis extending parallel to the translator / axis such that when the contact pin traverses the alignment opening towards the pin area, the contact pin is aligned along the translator / axis with the pin area.

[0011]

[0007] In other words, the electronics unit comprises a connector for establishing an electric connection between the electronics unit and the electric motor. Commonly, the electric connection will be formed between a printed circuit board of the electronics unit and the stator of the electric motor. For example, the connection may be to an Earth pin provided at the stator of the electric motor. The electronics unit, for example, controls the speed and torque of the motor and may also monitor various parameters of the motor.

[0008] The connector itself is provided os a separated part that is attached to or mounted in the electronics unit before the electronics unit is mounted to the electric motor. For example, the electronics unit may comprise a plastic mounting structure that is part of the housing which holds the connector. Additional mounting structure may be provided on a printed circuit board of the electronics unit. Alternatively, the connector may be molded into the housing or a support structure of the electronics unit.

[0012]

[0009] The electronics unit is mounted to the electric motor of the centrifugal pump by means of a translational movement, i.e., the electronics unit is pushed onto the electric motor in a straight movement without any intended rotations. The translational movement is made along a translator / axis.

[0013]

[0010] The connector is configured so that when the electronics unit is mounted to the electric motor, an electric connection is established between the electric motor and the electronics unit. The connector is intended to establish a connection to a contact pin that is provided on the electric motor. For example, the contact pin may form an Earth of the conductive stator housing or motor housing of the electric motor. The contact pin extends parallel to the translator / axis when the connection is established.

[0014]

[0011] For reliably connecting the electronics unit to the contact pin of the electric motor, the connector comprises a guide means and a contact means. The guide means is provided for aligning the electronics unit with the contact pin and the contact means provides the actual electric connection between the contact pin and the connector. The guide means is generally plate-shaped and extends perpendicular to the translator / axis. The guide means could, for example, be made from a metal sheet extending in a transversal plane. An element may, for example, be deemed plate-shaped if its extension in one plane exceeds the thickness of the element perpendicular to that plane by one order of magnitude or more.

[0015]

[0012] Further, the plate-shaped guide means comprises an alignment opening in which the contact pin is received. The alignment opening is intended to define the position of the contact pin relative of the electronics unit in a plane extending perpendicular to the translator / axis and thus perpendicular to a longitudinal axis of the contact pin. For example, the edge of the pin area may have a similar shape as the outer circumference of the contact pin but is preferably wider than the contact pin. Thus, when the contact pin is inserted in the center of the pin area, it does preferably not touch the guide means if the contact pin is centered along the translator / axis with the pin aera.

[0016]

[0013] The contact means is provided on the connector for establishing the actual electric connection between the contact pin on the electric motor and the electronics unit. The contact means is formed by at least and preferably exactly three contact elements. Each of these contact elements comprises a pin area that is intended to be in contact with an outer surface of the contact pin when the electronics unit has been attached to the electric motor. The contact elements are elastic and at least the contact surface of the contact elements is intended to be pushed out of the pin area by the contact pin. This causes the contact elements to be biased against the contact bin when the electronics unit has been attached to the electronics unit and ensures a reliable electric contact. While the contact elements are deemed to deform elastically when pushed out of the pin area by the contact pin, this does not preclude that there is also a limited plastic deformation of the contact elements, i.e., the contact elements may partially deform permanently when the contact pin is pushed into pin area.

[0014] Finally, the pin area defined by the at least three contact elements and the alignment opening defined by the plate-shaped are aligned on an axis extending parallel to the translator / axis, i.e., an axis extending perpendicular to the transversal plane of the plate-shaped alignment means. Further, the width of the alignment opening is restricted so that for passing through the alignment opening, the contact pin has to be aligned with the pin area along the translator / axis. In other words, once the contact pin has passed through the alignment opening, it is necessarily aligned along the translator / axis with the pin area.

[0017]

[0015] For example, the center of the pin area as defined by the contact surfaces of the three or more contact elements may be aligned with a center of the circular alignment opening and the width of the alignment opening may be only slightly wider than the expected with of the contact pin. The alignment opening hence advantageously ensures that the contact pin is directly aligned with the subsequent pin area along the translator / axis and is centered with respect to the contact elements. This avoids damage to the contact elements due to a misaligned contact pin during assembly of the centrifugal pump. The load of a misaligned contact pin is not carried by the contact elements but by the structurally more robust alignment means.

[0018]

[0016] In a preferred embodiment, the contact surface is in an initial position when the electronics unit is detached from the electric motor. The contact surface is displaced from the initial position by the contact pin when the electronics unit is being mounted to the electric motor to a displaced position. When being displaced from the initial position to the displaced position, the contact surface moves further parallel to the translator / axis than perpendicular to the translator / axis.

[0019]

[0017] As previously discussed, the contact elements are elastic elements that are displaced when the contact pin is inserted into the pin area as defined by the contact means and thereby biased towards the contact pin. In the present embodiment, the distance the contact elements are displaced is defined in terms of the displacement parallel to the translator / axis, i.e., parallel to the movement of the contact pin, and in a transversal plane extending perpendicular thereto, i.e., in a plane extending parallel to the transversal plane of the plate-shaped alignment means. According to the preferred embodiment, the contact surfaces move further parallel to the translator / axis when displaced by the contact pin as perpendicular thereto. For example, a contact element may be configured to that it is bend by the contact pin further upwards away from the alignment opening parallel to the translator / axis as it is pushed sideways out of the pin area. This reduces the load the contact elements experience when the contact pin is inserted into the contact area.

[0020]

[0018] In a preferred embodiment, the contact elements of the connector branch off the plate-shaped guide means at a transitioning area. The contact elements are thus directly attached to or formed on the guide means which extends perpendicular to the translator / axis which makes for a particularly robust support against any forces acting perpendicular to the translator / axis.

[0021]

[0019] Preferably, in the initial position of the contact surface the contact surface is spaced perpendicular to the translator / axis further away from the transitioning area than parallel to the translator / axis. In other words, the distance between the transitioning area where the contact element is attached to the guide means and the contact surface of the contact element is greater perpendicular to the translator / axis than parallel to the translator / axis. Any displacement of the contact surface is thus predominantly parallel to the translator / axis when the contact pin is inserted into the contact area minimizing shear loads that could damage the contact elements.

[0020] Further preferably, the contact elements are S-shaped. This allows the contact element to branch off the plate-shaped guide means essentially parallel to the translator / axis, continue with an elongated section which is generally perpendicular to the to the translator / axis before merging in a contact section. The contact section extends essentially parallel to the translator / axis and comprises the contact surface. Since the contact pin extends parallel to the translator / axis, a contact surface also extending parallel to the translator / axis allows for an extended contact between the parts and an improved conductivity.

[0022]

[0021] In another preferred embodiment, each contact element comprises a leg extending radially away from the contact surface of the respective contact element. The legs of all contact elements extend essentially perpendicular to the translator / axis when the electronics unit has not been mounted to the electric motor. The legs of all contact elements are attached to a common support.

[0023]

[0022] Hence, in the preferred embodiment each contact element is formed as an elongated leg. The legs of all contact elements extend radially away from the respective contact surfaces of the contact elements. In some embodiments, this may coincide with the legs extending radially away from a common center point of all contact surfaces which may, for example, be formed by a center of the pin area. However, in other embodiments this may not be the case.

[0024]

[0023] Further, it is preferred for the contact elements to extend essentially perpendicular to the translator / axis when they are not in contact with a contact pin, i.e., when the electronics unit has not been attached to the electric motor, and all contact elements are supported on or attached to a common support. For example, the contact elements including the support could be made from a sheet of metal. When the contact elements engage the contact pin, they bend upwards, i.e., away from the guide means. Preferably, the contact elements are equidistantly spaced about the contact area, whereby the contact elements center the contact pin. However, it is noted that the contact elements may be bend slightly out of the plane and away from the plate-shaped guide means to facilitate insertion of the contact pin. While the legs of the contact elements are in this case not strictly perpendicular to the translator / axis, they are deemed to extend essentially perpendicular thereto as the extension perpendicular to the axis by far exceeds the extension parallel to the translator / axis.

[0025]

[0024] In another embodiment, two contact elements of the three or more contact elements form a generally horseshoe-shaped wall partially surrounding the pin area and extending generally parallel to the translator / axis away from the plate-shaped guide means. In this preferred embodiment, the plate-shaped guide means the contact elements do not necessarily have to be directly formed on the plate-shaped guide means. Rather, the guide means may also be formed as a separate part, for example, in form of a washer that is connected to the remainer of the connector when it is installed in the electronics housing. Two of the contact elements are formed at the opposing free ends of the horseshoe-shaped wall, whereas a third contact elements as a leg extending essentially at the center of the horseshoe-shaped wall.

[0026]

[0025] In a preferred embodiment, the plate-shaped guide means is attached via a bar extending in the transversal plane to the remainder of the connector. The bar is configured to be supported on a support structure of the electronics unit against bending out of the transversal plane when the electronics unit is being mounted to the electric motor. Hence, in the preferred embodiment the plate-shaped guide means is attached via a flat bar or rod to the remainder of the connector. The bar extends in the same plane as the plate-shaped guide means. It provides a con- nection of the guide means to the remainder of the connector. This connection is robust against displacement or deformation in the transversal plane. Furthermore, the bar is particularly suitable for being supported or held by a support structure of the electronics unit. Such a support would prevent bending of the guide means out of the transversal plane caused by the contact pin.

[0027]

[0026] Preferably, the connector is formed as a single piece. Further preferably, the connector is made from a single metal sheet. The single metal sheet may be formed as the connector by bending the pre-cut parts into shape.

[0028]

[0027] Preferably, an electronics housing of the electronics unit is formed using plastic injection molding. The connector is molded into the housing. Hence, in the preferred embodiment the connector is not installed in a prefabricated housing part of the electronics unit but placed in a mold for a part of the electronics housing. For example, the connector may be placed in a mold for a bottom part or bottom cover of the electronics housing before the mold is closed and the plastic is injected into the mold. Molding the connector into the housing secures the connector particularly well in the housing and allows a robust support of the connector against forces exerted, for example, by the contact pin when the electronics unit is attached to the electric motor. Further, when the housing part is molded with the connector in place, the housing can be tightly sealed where the connector extends through the housing. However, embedding the connector in the mold also necessitates a particularly robust connector element as the connector element cannot be replaced without replacing the entire housing part.

[0029]

[0028] In another preferred embodiment, an outer rim of the plate-shaped guide means is molded into a part of the electronics housing, thereby supporting the plate-shaped guide means against movement parallel to the translator axis. In other words, an outer rim of the plate-shaped guide means is at least partially embedded in a wall or other structure of the housing. This keeps the plate-shaped guide means in place both against movement parallel to and perpendicular to the translator / axis.

[0030]

[0029] In a second aspect, the problem underlying the present invention is solved by a centrifugal pump comprising an electronics unit according to any of the preceding embodiments and an electric motor. The electric motor comprises a contact pin extending parallel to the translator / axis. With regard to the details and advantages of the embodiments of the centrifugal pump, reference is made to the preceding description of the electronics unit.

[0031]

[0030] In a third aspect, the problem underlying the present invention is solved by a method for assembling an electronics unit according to any of the preceding embodiments. The method involves the steps of forming the plate-shaped guide means and the contact means of the connector from sheet metal and integrating the connector into the electronics unit. Preferably, the connector is cut in one or multiple parts from sheet metal using, for example, die cutting, embossing, or other cutting methods. Afterwards, the parts of the sheet are preferably brought into the desired shape by bending or other forming techniques. The preformed connector is then integrated into an electronics housing, for example, by mounting the connector on support structures in a preformed part of the electronics housing.

[0032]

[0031] However, in a preferred embodiment the step of integrating the connector into the electronics unit comprises placing the connector in a mold for a part of an electronics housing of the electronics unit and forming the part of the electronics housing using plastic injection molding. The part of the housing is preferably a bottom cover of the electronics hous- ing. The advantages of molding the connector into the electronics housing have previously been described. Therefore, reference is made to the preceding description to avoid unnecessary repetitions.

[0033]

[0032] In the following, the present invention will be described in more detail with regard to exemplary embodiments shown in the figures, wherein

[0034] Figure I shows a perspective view of an exemplary embodiment of a centrifugal pump,

[0035] Figure 2 shows a sectional view of an exemplary embodiment of an electronics unit without a front cover and part of an exemplary embodiment of an electric motor,

[0036] Figure 3 shows a top perspective of part of the exemplary embodiment of Figure 2,

[0037] Figure 4 shows a bottom view of the exemplary embodiment of Figure 2 with a different exemplary embodiment of a connector,

[0038] Figure 5 shows a top view of a lower part of an electronics housing of the exemplary embodiment of Figure 5,

[0039] Figure 6 shows a perspective view of an exemplary embodiment of a connector,

[0040] Figure 7 shows a second perspective view of the exemplary embodiment of a connector Figure 6 with part of an exemplary embodiment of an electric motor,

[0041] Figure 8 shows a detailed perspective view of a guide means and a contact means of the exemplary embodiment of a connector shown in Figures 2, 3, 6, and 7,

[0042] Figure 9 shows a detailed perspective view of a guide means and a contact means of another exemplary embodiment of a connector, Figure 10 shows a detailed perspective view of a contact means of the exemplary embodiment of a connector of Figures 4 and 5, and

[0043] Figure 1 1 shows a flow chart for an exemplary embodiment of a method for assembling an electronics unit.

[0044]

[0033] Figure 1 shows an exemplary embodiment of a centrifugal pump 1 . The centrifugal pump 1 is a heating circulation pump for domestic use. The centrifugal pump 1 comprises a pump housing 3 with a suction side inlet 5a and a pressure side outlet 5b. The pump housing 3 surrounds an impeller (not shown) which is driven by a wet-running electric motor 7. The electric motor 7 comprises a rotor and a stator (not shown in Figure 1 ) which are located inside a motor housing 9.

[0045]

[0034] On the opposite side of the pump housing 3, an electronics unit 1 1 is attached to the electric motor 7. The electronics unit 1 1 comprises an electronics housing 13 with a bottom cover 15 and a top cover 17. At the top cover 17, several illuminated symbols 1 are provided that convey information regarding the status of the centrifugal pump 1 to a pump operator. The bottom cover 15 comprises two sockets 21 a, 21 b. A first socket 21 a is used for power supply, wherein a second socket 21 b can be used for supplying signals from external sensors to the electronics unit 1 1.

[0046]

[0035] Figure 2 shows a partial cut through the bottom cover 15 of the electronics unit 1 1 . Further views of the same exemplary embodiment of a bottom cover 15 are shown in Figures 3 to 5. Figures 4 and 5 show the same bottom cover 15 as the exemplary embodiment shown in Figures 2 und 3. However, the motor housing 9 is not shown and a different connector for establishing an electric connection to the electric motor is used. Subsequently the bottom cover 15 will be described with reference to Figures 2 to 5 to discuss identical features. Relevant differences between the embodiments will be pointed out.

[0047]

[0036] As can be seen from Figure 2, the electronics unit 15 comprises a printed circuit board or PCB 23 which comprises various electronics controlling the operation of the centrifugal pump 1 and the illuminated symbols 19. The PCB 23 is not shown in Figures 3 to 5.

[0048]

[0037] The bottom cover 15 of the electronics unit 1 1 is mounted to the motor housing 9 which may also be referred to as the stator housing. In the exemplary embodiment shown in the Figures, the motor housing 9 is made from cast iron, i.e., the motor housing 9 is made from an electrically conductive material. During assembly of the centrifugal pump 1 , the electronics unit 1 1 is attached to the motor housing 9 by means of a translational movement along a translator / axis 25. In other words, the electronics unit 1 1 is pushed onto the motor housing 9 in a linear movement without any rotational movement.

[0049]

[0038] The cast iron motor housing 9 is conductive and has an Earth contact pin 27. The contact pin 27 extends generally parallel to or along the translator / axis 25 and comprises an outer thread 29a allowing the contact pin to be screwed into a mating inner thread 29b formed at the motor housing 9. The contact pin 27 is also made from a conductive material such as bronze, for example, CuSn6 R560. Hence, due to the metalmetal connection between the contact pin 27 and the motor housing 9, an electrical connection between the motor housing 9 and the contact pin 27 is established.

[0050]

[0039] At an opposing end 31 of the outer thread 29a, the contact pin 27 is configured to enable a reliable connection to a connector 33 of the electronics unit 1 1. The opposing end 31 is largely formed as cylindrical shaft 31 a with a tapering tip 31 b. Between the tapering tip 31 b and the cylindrical shaft 31 a, a necking area 31 c extending circumferentially about the contact pin 27 is formed. At the necking area 31 c, the contact pin 27 has a reduced outer diameter compared to the cylindrical shaft 31 a and the shaft-facing bottom end of the tapering tip 31 b. The necking area 31 c is provided for locking with a contact means 35 of the connector 33.

[0051]

[0040] Between the outer thread 29a and the cylindrical shaft 31 a, the contact pin 27 comprises a stepped collar 37. A lower part 37a of the stepped collar 37 delimits how far the contact pin 27 can be screwed into the motor housing 9. An upper part 37b of the stepped collar 37 is octagonal allowing the contact pin 27 to be screwed into the motor housing 9 using a common wrench as can be seen best in Figure 7. The lower part 37a and the upper part 37b of the contact pin 27 have been designated with reference numerals in Figure 7 but not in Figure 2 to keep the latter intelligible.

[0052]

[0041] Figures 2, 3 as well as 6, 7 and 8 show a first exemplary embodiment of a connector 33. While Figure 6 shows the connector 33 in isolation, Figure 7 shows the connector 33 together with part of the motor housing 9 and the contact pin 27. Figure 8 shows only a part of the connector 33. In Figures 4, 5 and 10 a second exemplary embodiment of a connector 33 is shown. Figure 9 shows another exemplary embodiment of a connector 33. The exemplary embodiments of connectors 33 only differ in the part that is used for establishing the connection with the contact pin 27. While each embodiment of the connector 33 comprises a contact means 35, the implementation of the contact means 35 differs in several features. Subsequently, the first exemplary embodiment will be described in detail before elaborating on the differences of the other embodiments.

[0042] In all embodiments the connector 33 comprises a plate-shaped guide means 39 extending in a translational plane that is generally perpendicular to the translator / axis 25. A first exemplary embodiment of a guide means 39 is shown in Figures 2,3, 6-8, a second exemplary embodiment of a guide means 39 is shown in Figures 4, 5 and 1 1 , a third exemplary embodiment of a guide means 39 is shown in Figure 9 and a fourth exemplary embodiment of a guide means 39 is shown in Figure 10.

[0053]

[0043] The plate-shaped guide means 39 is attached via a bar 41 to the remainder of the connector 33 in all embodiments. The connector 33 further comprises a press-fit PCB plug 43 in all embodiments. The PCB plug 43 engages a mating PCB socket 45 formed in the PCB 23.

[0054]

[0044] In addition to the PCB plug 42, the connector 33 comprises in all embodiments a separate external contact 47 which is located in one of the sockets 21 a that are provided on the outside of the bottom cover 15. The external contact 47 is only shown in Figures 5 and 7. It is noted that the external contact 47 is formed in one piece with the remainder of the connector 33 and provides an outside Earth connection for the motor housing 9 in the exemplary embodiment.

[0055]

[0045] The connector 33 rests in all embodiments on various support elements that are formed by the electronics housing 13 and, to be more precise, by the bottom cover 15 of the electronics unit. The bottom cover 15 thus forms a support for the connector 33 which keeps the connector 33 in place.

[0056]

[0046] As can be seen best in Figures 4 and 5, the bottom cover 15 of the electronics unit 1 1 comprises two additional connection elements 49a, 49b for establishing electric connections between the electronics unit 1 1 and the electric motor 7. A first, three-contact connection element 49a forms a power supply for the electric motor 7 through which the speed and torque of the electric motor 7 and thus the operation of the centrifugal pump 1 can be controlled. The first connection element 49a is formed a conventional plug with three pins and will therefore not be discussed in further detail.

[0057]

[0047] The second connection element 49b comprises a plate-shaped guide element 39 and a contact means 35 which are identical to the plate-shaped guide element 39 and the contact means 35 of the connector 33 of the exemplary embodiment shown in Figures 4, 5, and 1 1 . No details of the second connection element 49b are shown. However, the subsequent detailed description of the plate-shaped guide element 39 and the contact means 35 of the connector 33 shown in Figures 4, 5, and 1 1 also applies to the second connection element 49b.

[0058]

[0048] Subsequently, the contact means 35 and the plate-shaped guide means 39 of the first exemplary embodiment of a connector 33 will be described in more detail with reference to Figures 6, 7, and 8. The same exemplary embodiment of a connector 33 is also shown in Figures 2 and 3.

[0059]

[0049] The plate-shaped guide means 39 extends perpendicular to the translator axis 25 and is formed from a metal sheet. The metal sheet surrounds an alignment opening 51 which has the about the same circular outer circumference as the cylindrical shaft 31 a of the contact pin 27 but a wider diameter. The alignment opening 51 is provided to ensure that the contact pin 27 is aligned with the contact means 35 once the contact pin 27 has been inserted into the alignment opening 51. If the contact pin 27 is slightly misaligned when the electronics unit 1 1 is attached to the electric motor 7, the tapering tip 31 b of the contact pin 27 will engage an edge of the alignment opening 51 and aligns the parts along the translator / axis 25. The width of the alignment opening 51 is, therefore, limited so that it ensures that the contact pin 27 can only traverse the plate-shaped guide means 39 it is aligned along the translator / axis 25 with the pin area. It is noted that not all reference numerals designating features of the contact means 35 and the plate-shaped guide means 39 are shown in each of Figures 6, 7, and 8 to keep the Figures intelligible.

[0060]

[0050] Three elastic contact elements 53a, 53b, 53c forming the contact means 35 branch off the plate-shaped guide mean 39 at respective transitioning areas 54. The contact elements 53a, 53b, 53c are equidistantly spaced from each other. The contact elements 53a, 53b, 53c are formed from the same metal sheet as the guide means 39 and bend into an S shape. Thus, in the exemplary embodiment shown in Figures 2, 3, 6, 7, and 8, the entire connector 33 including the contact means 35 and the guide means 39 is formed from a single piece of metal sheet in one piece. The metal is preferably a copper alloy such as bronze, e.g., CuSn6 R560.

[0061]

[0051] Each of the contact elements 53a, 53b, 53c comprises a contact surface 55 which is intended to be in direct contact with the contact pin 27 when the electronics unit 1 1 has been attached to the electric motor 7. The contact surfaces 55 are arranged about a common pin area 57 which receives the contact pin 27. The pin area 57 is aligned with the alignment opening 51 along translator / axis 25. When the electronics unit 1 1 is being attached to the electric motor 7, the tapering tip 31 b first passes through the alignment opening 51 before entering the pin area 57.

[0062]

[0052] The width of the pin area 57 between the contact surfaces 55 is less than an outer diameter of the contact pin 27 at the bottom end of the tapering tip 31 a and the cylindrical shaft 31 a. The contact surfaces 55 are therefore pushed outward and the contact elements 53a, 53b, 53c are bend outwards when the contact pin 27 is inserted into the pin area 57. Since the distance between the contact surfaces 55 and the respective transitioning area 54 is greater perpendicular to the translator / axis 25 than parallel thereto, the contact surfaces 55 are displaced further along the translator / axis 25 than perpendicular thereto. This reduces the mechanical stress acting on the contact elements 53a, 53b, 53c which avoids damages. Further, bending the contact elements 53a, 53b, 53c outwards biases the contact elements 53a, 53b, 53c towards the contact pin 27 ensuring a robust electrical contact.

[0063]

[0053] In the exemplary embodiment shown in Figures 6, 7, and 8, the contact elements 53a, 53b, 53c are bend in an S-shape so that the contact surfaces 55 are protruding furthest out towards the translator / axis 25 or the center of the pin area 57. The contact surfaces 55 thus engage the necking area 31 c of the contact pin 27, thereby holding the contact pin 27 in placed and preventing unintended movement along the translator / axis 25.

[0064]

[0054] Figures 4, 5, and 10 shows a second exemplary embodiment of a connector 33 with plate-shaped guide means 39 that is very similar to the plate-shaped guide means 39 previously described with reference to Figures 6, 7, and 8. Therefore, reference is made to the previous description of the plate-shaped guide means 39.

[0065]

[0055] As can be seen best in Figure 10, the contact means 35 does not comprise three identical and equidistantly spaced contact elements 53a, 53b, 53c. Two contact elements 53a, 53b are formed by opposing free ends 60a, 60b of a horseshoe-shaped structure 59 that surrounds the pin area 57. The horseshoe-shaped structure 59 has at is end facing towards the guide means 39 protrusions or bulges 62 forming the contact surface 57. The protrusion is intended to engage the necking area 31 c on the contact pin 27 to lock a position of the contact pin 27 along the translator / axis 25.

[0056] Further, contact means 35 comprises a third contact element 53c which is formed as a leg that extends generally parallel two the translator / axis 25. The third contact element 53c is tilted towards the pin area 57 and deforms elastically when the contact pin 27 is inserted into the contact area 57. In the exemplary embodiment shown in Figure 10, the plate-shaped guide means 39 may be formed as a separate part from the contact means 35 so that the connector 33 is only assembled when it is attached to or mounted in the electronics housing 13.

[0066]

[0057] Figure 9 shows a third exemplary embodiment of contact means 35 for a third exemplary embodiment of a connector 33. The plateshaped guide means 39 is very similar to the plate-shaped guide means 39 previously described with reference to Figures 6, 7, and 8. Therefore, reference is made to the previous description of the plate-shaped guide means 39. With regard to the contact means 35, only the differences from the preceding embodiments will be described in more detail.

[0067]

[0058] The contact means 35 is in Figure 9 is also formed from a single metal sheet with three contact elements 53a, 53b, 53c. Each of the contact elements 53a, 53b, 53c is formed by a metal leg 61 extending radially away from a center of the pin area 57 and the respective contact surfaces 55. The elastic metal legs 61 are attached to a common support 63. The legs 61 are slightly bend out of the plane of the common support 63 and away from the guide means 39 to facilitate insertion of the contact pin 27. When the contact pin 27 is inserted, the legs 61 are bend further upwards and away from the guide means 39 so that they are biased towards the contact pin 27. Further, the contact surfaces 55 formed at the free ends of the legs 61 engage the necking area 31 c of the contact pin 27 to lock the position of the contact pin 27 along the translator / axis 25.

[0059] In each of the embodiments, the electronics unit 1 1 is assembled by forming the connector 33 from sheet metal in a first step 65. This may comprise in first sub-step 65a cutting connector blanks from a single metal sheet, preferably, as a single piece, and bringing the connector blanks in the shape shown, for example, in Figures 6 and 7 by plastically deforming the blanks in a second sub-step 65b.

[0068]

[0060] In a second step 67, the connector 33 is mounted in the electronics housing 13, for example, the bottom cover 15 of the electronics housing 13. Mounting the connector 33 in the bottom cover 15 can be done by placing the connector 33 in a preformed bottom cover 15. However, in a preferred embodiment the connector 33 is placed in a mold third sub-step 67a for plastic injection molding. Afterwards, the mold is closed, and plastic is injected into the mold in fourth sub-step 67b.

[0069]

[0061] Molding the connector 33 into the bottom cover 15 is particularly advantageous as the connector 33 is rigidly secured in the electronics unit 1 1 . For example, as can be seen in particularly well in Figures 8 and 10, a support structure 69 can be formed in the mold which partially clamps a rim 71 of the guide means 39. The support structure 69 forms a cylindrical or conical shape which is, however, not closed. The support structure 69 is particularly well suited for taking up loads acting along the translator / axis 25 on the guide means.

[0070]

[0062] Likewise, support ribs 73 can be formed in the electronics housing 13. The connector 33 extends through the support ribs 73, i.e., there is no opening in the support tibs 73 for inserting the connector 33 which also makes for a particularly robust mounting. Finally, molding the bottom cover 15 with the connector 33 in place ensures that any openings 77 required in an outer wall 75 of the housing 13 are strictly confined to the dimensions required for the connector 33. This reduces the risk of any liquid entering the electronics housing 1 1 . List of reference numerals

[0071] I centrifugal pump

[0072] 3 pump housing

[0073] 5a suction side inlet

[0074] 5b pressure side outlet

[0075] 7 electric motor

[0076] 9 motor housing

[0077] I I electronics unit

[0078] 13 electronics housing

[0079] 15 bottom cover

[0080] 17 top cover

[0081] 19 illuminated symbols on top cover

[0082] 21 a socket

[0083] 21 b socket

[0084] 23 printed circuit board 25 translator / axis

[0085] 27 contact pin

[0086] 29a outer thread

[0087] 29b inner thread

[0088] 31 opposing end

[0089] 31 a cylindrical shaft

[0090] 31 b tapering tip

[0091] 31 c necking area

[0092] 33 connector

[0093] 35 contact means

[0094] 37 stepped collar

[0095] 37a lower part

[0096] 37b upper part

[0097] 39 plate-shaped guide means 41 bar

[0098] 43 PCB plug 45 PCB socket

[0099] 47 external contact 49a first connection element 49b second connection element

[0100] 51 alignment opening 53a contact element

[0101] 53b contact element

[0102] 53c contact element

[0103] 54 transitioning area

[0104] 55 contact surface

[0105] 57 pin area

[0106] 59 horseshoe-shaped structure 60a, 60b free end

[0107] 61 metal leg

[0108] 62 bulge

[0109] 63 support

[0110] 65 first step

[0111] 65a first sub-step

[0112] 65b second sub-step

[0113] 67 second step

[0114] 67a third sub-step

[0115] 67b third sub-step

[0116] 69 support structure

[0117] 71 rim

[0118] 73 support ribs

[0119] 75 outer wall

[0120] 77 opening

Claims

Claims1 . An electronics unit (1 1 ) for a centrifugal pump ( 1 ) with a connector (33) for electrically connecting the electronics unit (1 1 ) to an electric motor (7) of the centrifugal pump ( 1 ), wherein the connector (33) is configured to be mounted in the electronics unit (1 1 ) and to automatically establish an electric connection between the electronics unit ( 1 1 ) and the electric motor (7) when the electronics unit (1 1 ) is mounted to the electric motor (7) by means of a translational movement along a translator / axis (25), wherein the connector (33) comprises a plate-shaped guide means (39) for aligning the connector (33) with a contact pin (27) formed at the electric motor (7) and a contact means (35) for establishing an electric connection between the connector (33) and the contact pin (27), wherein the plate-shaped guide means (39) extends perpendicular to the translator / axis (25) in a transversal plane and comprises an alignment opening (51 ) for receiving the contact pin (27) extending parallel to the translator / axis (25), wherein the contact means (35) comprises three or more elastic contact elements (53a, 53b, 53c) surrounding a pin area (57) for receiving the contact pin (27), wherein each of the contact elements (53a, 53b, 53c) comprises a contact surface (55) which is in direct contact with the contact pin (27) when the electronics unit (1 1 ) has been mounted to the electric motor (7) and wherein each of the contact elements (53a, 53b, 53c) is biased towards the pin area (57) when the electronics unit (1 1 ) has been attached to the electric motor (7), and wherein the pin area (57) is aligned with the alignment opening (51 ) on an axis extending parallel to the translator / axis (25) such that when the contact pin (27) traverses the alignment opening (51 )towards the pin area (57), the contact pin (27) is aligned along the translator / axis (25) with the pin area (27).

2. Electronics unit (1 1 ) according to claim 1 , wherein each contact surface (55) is in an initial position when the electronics unit (1 1 ) is detached from the electric motor (7), and wherein the contact surface (55) is displaced from the initial position by the contact pin (27) when the electronics unit (1 1 ) is being mounted to the electric motor (7) to a displaced position, wherein when being displaced from the initial position to the displaced position the contact surface (55) moves further parallel to the translator / axis (25) than perpendicular to the translator / axis (25).

3. Electronics unit (1 1 ) according to claim 1 or 2, wherein the contact elements (53a, 53b, 53c) of the connector (33) branch off the plateshaped guide means (39) at a transitioning area (54).

4. Electronics unit (1 1 ) according to claims 2 and 3, wherein in the initial position of the contact surface (55), the contact surface (55) is spaced perpendicular to the translator / axis (25) further away from the transitioning area (54) than parallel to the translator / axis (25).

5. Electronics unit (1 1 ) according to claim 3 or 4, wherein the contact elements (53a, 53b, 53c) are S-shaped.

6. Electronics unit (1 1 ) according to claim 1 or 2, wherein each contact element (53a, 53b, 53c) comprises a leg (61 ) extending radially away from the contact surface (55) of the respective contact element, wherein the legs (61 ) of all contact elements (53a, 53b, 53c)extend perpendicular to the translator / axis (25) when the electronics unit (1 1 ) has not been mounted to the electric motor (7) and wherein the legs (61 ) of all contact elements (53a, 53b, 53c) are attached to a common support (63).

7. Electronics unit (1 1 ) according to claim 1 or 2, wherein two contact elements (53a, 53b, 53c) of the three or more contact elements (53a, 53b, 53c) form a generally horseshoe-shaped wall (59) partially surrounding the pin area (57) and extending generally parallel to the translator / axis (25) away from the plate-shaped guide means (39).

8. Electronics unit (1 1 ) according to any of the preceding claims, wherein the plate-shaped guide means (39) is attached via a bar (41 ) extending in the transversal plane to the remainder of the connector (33), wherein the bar (41 ) and / or a rim (71 ) of the plateshaped guide means (39) is configured to be supported on a support structure (69) of the electronics unit (1 1 ) against bending out of the transversal plane when the electronics unit (1 1 ) is being mounted to the electric motor (7).

9. Electronics unit (1 1 ) according to any of the preceding claims, wherein the connector (33) element is formed as a single piece and preferably formed from a single metal sheet.

10. Electronics unit (1 1 ) according to any of the preceding claims, wherein an electronics housing (13) of the electronics unit (1 1 ) is formed using plastic injection molding, and wherein the connector (33) is molded into the housing (13).1 1 . Electronics unit ( 1 1 ) according to claim 10, wherein an outer rim (73) of the plate-shaped guide means (39) is molded into a support structure (69) of the electronics housing (13), thereby supporting the plate-shaped guide means (39) against movement parallel to the translator / axis (25).

12. A centrifugal pump (1 ) comprising an electronics unit (1 1 ) according to any of the preceding claims and an electric motor (7), wherein the electric motor (7) comprises a contact pin (27) extending parallel to the translator / axis (25).

13. A method for assembling an electronics unit (1 1 ) according to any of claims 1 to 1 1 , wherein the method comprises the steps of forming the plate-shaped guide means (39) and the contact means (35) of the connector (33) from sheet metal, and integrating the connector (33) into the electronics unit (1 1 ).

14. Method according to claim 13, wherein the step of forming the plate-shaped guide means (39) and the contact means (35) of the connector (33) from a metal sheet comprises cutting the connector (33) from a single metal sheet and bending the connector (33) in shape.

15. Method according to claim 13 or 14, wherein the step of integrating the connector (33) into the electronics unit (1 1 ) comprises placing the connector (33) in a mold for a part of an electronics housing of the electronics unit (1 1 ) and forming the part of the electronics housing (13) using plastic injection molding, wherein the part of the electronics housing (13) is preferably a bottom cover (15) of the electronics housing (13).

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