Electric drive unit for a pump, and pump

Abstract

The invention relates to an electric drive unit for a pump, in particular for a centrifugal pump, comprising an electric drive motor and an electronics housing which is attached on the peripheral side of the housing of the drive motor, contains the necessary electronics for open-loop / closed-loop control of the rotational speed of the motor, and on the lower side of which, facing the drive motor, there is a cooling element, wherein at least one fan is provided which generates a cooling air flow which flows around the outer side of the motor on the peripheral side, characterized in that at least one guiding element which is configured as a separate component is introduced between the electronics housing and the motor housing, which guiding element branches off a part air flow of the cooling air flow generated by the fan and, with the cooling element of the electronics housing, forms a flow duct for the part air flow in order to cool the electronics in the electronics housing.

Description

[0001] Electric drive unit for a pump and pump

[0002] The invention relates to an electric drive unit for a pump, in particular for a centrifugal pump, comprising an electric drive motor and an electronics housing mounted circumferentially on the housing of the drive motor, which contains the necessary electronics for speed control of the motor and on whose underside facing the drive motor a heat sink is provided, wherein the drive unit has at least one fan which generates a cooling air flow flowing circumferentially around the outside of the motor.

[0003] Cost-effective and efficiently controlled pump drives generally require a high level of component integration. In particular, the electric drive motor and an inverter for speed control are becoming increasingly closely coordinated. It has proven advantageous to use a fan intended for cooling the drive motor for parallel cooling of the frequency converter. This eliminates the need for an additional fan for the converter electronics.

[0004] In known designs, the inverter's electronics housing is placed on the periphery of the motor housing. Cooling fins located on the underside of the electronics housing are surrounded by the airflow generated by the motor fan, allowing the heat loss from the electronics housing to be transferred from the electronics housing to the airflow and dissipated. However, the peripheral mounting of the electronics housing and the creation of a separate flow channel for cooling the inverter require modifications to the motor housing. For drive units produced in high quantities, the resulting development costs are acceptable; however, smaller production runs do not justify such modifications, so a solution is desirable that enables the mounting of different electronics housings on electric motors without modifications to the motor housing.

[0005] This object is achieved by an electric drive unit having the features of claim 1. Advantageous embodiments of the drive unit are the subject of the dependent claims.

[0006] According to the invention, it is proposed to insert at least one guide element configured as a separate component between the electronics housing and the motor housing. With the aid of the additional guide element, a partial air flow of a cooling air flow generated by the drive fan can be diverted and redirected to the heat sink of the electronics housing. The guide element and heat sink of the electronics housing form a flow channel for the diverted partial air flow to ensure adequate cooling of the electronics in the electronics housing.

[0007] The introduction of a separate guide element eliminates the need for costly modifications to existing motor types, especially existing motor housings, thus eliminating or at least reducing additional development effort. Ideally, no special structural provisions are required on the motor housing or motor fan to create a partial airflow for cooling the converter electronics installed on the motor. Instead, the air branching is preferably realized solely through the integrated guide element. Such an additional guide element is simpler and / or more cost-effective to manufacture.

[0008] The flow channel according to the invention is preferably formed by a specific distance between the guide element and the underside of the electronics housing. In principle, the guide element and motor housing can also be mounted at a distance from each other. The cavity formed by the distance could then also be flowed through by the cooling air from the motor fan, so that the motor housing can also be cooled in the motor housing area located directly below the guide element. However, this is not absolutely necessary for the implementation of the inventive concept and is therefore considered merely an optional feature.

[0009] The fan design is fundamentally arbitrary, but it is preferred if the fan includes a fan impeller mounted on the motor shaft. Such a fan impeller is typically located on the front of the motor housing and is covered by a separate fan cover. The branched flow channel for cooling the electronics housing is then formed, at least in the branching area, by the guide element and the fan cover or the electronics housing.

[0010] The resulting branched flow channel can, in principle, be open. However, a closed design, at least in sections, especially immediately after the branch, is preferred, since a closed channel shape typically achieves a greater cooling effect. Ideally, the flow channel is almost completely closed over its entire length, parallel to the drive shaft. At least one opening is provided at the end of the channel to release the heated air.

[0011] According to a preferred embodiment, the guide element is essentially plate-shaped, with the plate surface preferably extending parallel to the underside of the electronics housing and / or the drive shaft. The cavity existing between the plate surface and the underside of the electronics housing corresponds to the flow channel.

[0012] It may be preferred if the plate-shaped guide element comprises at least two side walls which extend at least over a partial section of the flow channel and close it off laterally towards the outside. Such side walls extend, for example, perpendicularly from the surface of the guide element in the direction of the underside of the electronics housing; ideally, these side walls contact the underside of the housing or are at a minimal distance from the underside of the housing or the heat sink. Alternatively or additionally, it is conceivable for such side walls to also extend on the underside of the electronics housing in the direction of the guide element in order to close the channel. It is also conceivable for the closed channel shape to be formed by both side walls of the electronics housing and side walls of the guide element.

[0013] In addition to the flow-guiding properties of the guide element, it can also perform a supporting function for the electronics housing. The guide element preferably comprises suitable means for supporting and / or fixing the electronics housing to the guide element. The guide element itself can be mounted circumferentially on the motor. The connection between the electronics housing and the guide element can be positive or non-positive. Screwing the guide element to the electronics housing is preferred. Screwing the guide element to the motor housing is also preferred. If the guide element does not perform a supporting function, the guide element can be provided with one or more passages for fastening devices such as screws, so that the electronics housing can be directly connected, in particular screwed, to the motor housing.If the guide element is load-bearing, the guide element also has an adapter function that enables the mounting of different electronics housings on motors without adapting the motor housings.

[0014] The guide element can also be equipped with at least one feedthrough for the electrical connection between the motor and the electronics housing. The feedthrough can be an opening which, in particular, has walls projecting from the guide element and extending in the direction of the electronics housing. This forms a type of connecting channel which runs perpendicular or almost perpendicular to the flow channel. Such a feedthrough can also be shaped to accommodate at least part of an electrical plug connection. In particular in the case of a guide element with a load-bearing function, the guide element can expediently be designed in two or more parts. Different parts of the multi-part guide element can be made from different materials. It can be useful, for example, to haveIt may be advisable to manufacture load-bearing and, if necessary, air-conducting parts of the guide element from a different material, especially a more stable material, than those parts that merely perform an air-conducting function. In general, the guide element can be manufactured from plastic and / or metal.

[0015] It can preferably be provided that the guide element is provided with one or more ribs which extend from a surface of the guide element facing the electronics housing through the formed flow channel in the direction of the electronics housing. The ribs serve as additional air guide elements in order to guide and, if necessary, redirect the air flowing in the flow channel. It is particularly preferred if at least some of these ribs form a continuation of existing ribs of the heat sink of the electronics housing, in particular a continuation of the ribs of the heat sink in the longitudinal direction of the flow channel. For example, the heat sink of the electronics housing can be provided with one or more cooling ribs which run parallel to the drive shaft in order to optimise the heat dissipation of the waste heat produced by the electronics. At the end of these cooling ribs, there can then be a continuation through ribs of the guide element in order to direct the heated air flow, for example.to divert the air outward from the flow channel in a controlled manner. The ribs of the guide element can preferably have a slope toward the drive shaft in order to direct the air flowing in the flow channel laterally out of the flow channel between the electronics housing and the guide element. It is conceivable, for example, that the ribs have a nearly perpendicular slope to the drive shaft.

[0016] The selected distance between the plate surface of the plate-shaped guide element, which runs parallel to the housing underside, and the underside of the electronics housing can vary in the longitudinal and / or transverse direction of the flow channel. In principle, the greatest possible distance between the guide element and the underside of the housing is preferred in order to achieve maximum volume flow and / or maximum dimensioning of the heat sink of the electronics housing. Specific surface contours on the outer circumference of the motor housing, such as a junction box, reduce the possible free space between the guide element and the electronics housing. However, to maximize the free space between the guide element and the electronics housing, the guide element can be designed with shoulders or steps so that the distance between the guide element and the electronics housing only needs to be reduced in certain areas, particularly in the area of ​​specific surface contours of the motor housing.

[0017] In the area where the air flow branches off from the fan's cooling flow, the guide element can have a surface section inclined relative to the drive shaft in order to branch off a partial air flow from the fan's main air flow and redirect it towards the electronics housing. The flow channel is therefore formed by a surface section running diagonally to the drive shaft, which then merges into the surface section of the guide element running parallel to the drive shaft. Furthermore, the inclined surface section can initially have a surface section that is perpendicular or almost perpendicular to the drive shaft. In this case, perpendicular does not mean that the perpendicular surface section must be at an exact angle of 90° to the drive shaft. An angle between 80° and 100° is also conceivable and sufficient.This vertical surface section extends from the guide element to the motor housing and preferably lies there in a sealing manner on the circumference, so that the air flow of the fan present across the entire width of the guide element is branched off and redirected in the direction of the electronics housing. For this purpose, the vertical surface section of the guide element has, in particular, a recess adapted to the outer contour of the motor housing, so that a sealing connection to the motor housing is possible. In this context, "sealing" does not necessarily mean a complete sealing effect; rather, it is sufficient if at least a substantial or predominant part of the air flow in this area is branched off to the electronics housing. In addition to the electric drive unit according to the invention, the present invention also relates to a pump, in particular a centrifugal pump, with an electric drive unit according to the invention.The pump therefore offers the same advantages and properties as those demonstrated above for the electric drive unit. For this reason, a repeated description is unnecessary.

[0018] Further advantages and features of the invention will be explained in more detail below with reference to the exemplary embodiments illustrated in the figures. They show:

[0019] Figure 1: a view of the fan-side end face of the electric drive unit according to the invention,

[0020] Figure 2: a side view of the drive unit according to Figure 1,

[0021] Figure 3: a longitudinal section along the section axis BB from Figure 1 ,

[0022] Figure 4: a perspective detailed view of the guide element for the inventive embodiment of Figures 1 - 3,

[0023] Figure 5: a fan-side view of a second embodiment of the drive unit,

[0024] Figure 6: a side view of the drive unit according to Figure 5,

[0025] Figure 7: a longitudinal section along the section axis BB of Figure 6,

[0026] Figure 8: another longitudinal section along the section axis AA according to Figure 5 and

[0027] Figure 9: a perspective detailed view of the guide element for the second embodiment shown in Figures 5 - 8. The invention will be described with reference to two exemplary embodiments of the electric drive unit. The electric drive unit serves to drive a hydraulic centrifugal pump which can be driven by a shaft emerging from the front of the motor housing. Figures 1 and 2 show different views of the electric drive unit. The reference numeral 1 designates the motor housing of an electric motor; the drive shaft emerging from one end of the motor housing on the drive side for driving the pump is designated 1a. On the opposite end, a fan impeller 3 is seated on the shaft 1a, whereby the fan impeller 3 generates a cooling air flow corresponding to the speed of the motor, which flows around the circumference of the motor housing 1 in the direction of the motor axis.The fan wheel 3 is covered by a fan cover 2 mounted on the front side of the motor housing 1, whereby air is sucked in by the fan wheel 3 through the grille 2a of the cover 2.

[0028] The electronics housing 4 with the necessary electronics for the implementation of a frequency converter is mounted on the circumference of the housing 1 of the electric motor.

[0029] The motor housing 1 comprises, in particular, a plurality of longitudinal cooling fins distributed over the circumference, through which the air flow generated by the fan 3 flows. However, according to the invention, a portion of the air flow distributed over the circumference of the motor housing is redirected to the electronics housing 4, in particular to a heat sink 4a located on the underside of the electronics housing 4, via which the waste heat generated by the electronics is to be dissipated into the cooling air flow.

[0030] The generated partial air flow is indicated by arrow 8 in Figure 3, which is a longitudinal section along axis BB of Figure 1. It can be seen that an additional guide element 10 is inserted between the electronics housing 4 and the motor housing 1, through which the air flow generated by the fan 3 is deflected upwards toward the electronics housing 4. Furthermore, a cavity exists between the guide element 10 and the heat sink 4a of the electronics housing, which serves as a flow channel running parallel to the drive shaft 1a, through which the branched partial flow 8 flows to the drive-side end of the electric motor. In addition to the guide element 10 and the heat sink 4a, the generated flow channel is also partially closed by the fan cover 2. The cover-like fan cover 2 is mounted on the front side of the fan-side end of the electric motor 1 and extends through a recess 2b to below the electronics housing 4.This formation 2b together with the guide element 10 forms the beginning of the flow channel.

[0031] A detailed illustration of the inserted guide element 10 can be seen in Figure 4. It can be seen here that the guide element 10 essentially has a plate-shaped surface that is spanned parallel to the underside of the electronics housing 4. At the fan-side end of the guide element 10 there is an inclined surface section 11 that runs diagonally to the motor axis and thereby deflects the air flow in the direction of the electronics housing 4. Furthermore, the inclined surface section 11 is followed by a surface section 12 that is perpendicular to the motor axis and borders the housing 1 of the electric motor. For this purpose, the vertical surface section 12 provides a circular recess 12a whose radius is adapted to the housing circumference, so that a certain degree of sealing is achieved by the contact of the surface section 12 with the motor housing 1 across the width of the guide element 10.The inclined surface section 11 also provides a recess 11a to create space for screwing an engine bearing cover onto the engine housing. Generally speaking, such a recess in this area can create space for a possible geometric element on the engine housing.

[0032] Two parallel side walls 14 extend perpendicularly from the plate surface of the guide element 10 at the side edge of the guide element. The side walls 14 extend up to the heat sink 4a, thereby completely closing the flow channel laterally. In this embodiment, however, the side walls 14 do not extend over the entire length of the guide element 10, but are provided only in a first surface section. The rear surface section of the guide element 10 no longer has side walls 14 projecting upwards toward the electronics housing, since the heat sink 4a provides corresponding ribs 4b or side walls 4b here to laterally close the flow channel.

[0033] It is also evident that the guide element 10 has a step 15, resulting in different distances between the guide element 10 and the underside of the electronics housing 4. This step 15 is due to a terminal box 1b installed on the motor housing 1, so that the rear part of the guide element 10 must be raised slightly in order to create sufficient installation space for the terminal box 1b. The terminal box is used to contact the electrical cables for the motor's power supply. For this reason, a feedthrough with a sleeve-like extension 16 towards the electronics housing 4 is provided at the level of the terminal box in order to be able to lead the connecting cables from the terminal box 1b to the electronics in a protected manner. The sleeve-like extension 16 is shaped in an aerodynamically optimized manner in order to reduce the air resistance generated in the flow channel.Alternatively, this element 16 can also be designed to serve as a receptacle for the motor-side part of a connector (not shown). With the help of a connector part mounted there, the electrical contact between the motor and the frequency converter is automatically established during assembly of the electronics housing 4.

[0034] The rear surface section of the guide element 10, which does not have side walls 14, can instead be provided with shortened side walls 13 that extend perpendicularly in the direction of the motor housing 1. These side walls are provided solely for assembly purposes. Holes 17 in both the side walls 14 and the side walls 13 enable the guide element 10 to be screwed to the electronics housing 4 or the heat sink 4a. Due to the mechanical connection between the guide element 10 and the housing 4, the guide element 10 also assumes a supporting function. The guide element can be screwed to the motor housing 1 via the holes 18 through the plate surface of the guide element 10. The guide element 10 thereby also assumes the function of an adapter that allows different converter housings 4 to be mounted on motors without modifying the motor housing 1. A slightly modified embodiment of the guide element 10 is shown in Figure 9 and Figure 10.shown in Figures 5 - 8. In this guide element 10, the side surfaces 14 are further reduced, since corresponding surface sections 4b of the heat sink 4a of the electronics housing 4 serve to close the resulting flow channel. It can also be seen that the terminal box 1b of the electric motor in this embodiment is provided at the fan-side end of the motor housing 1, so that the corresponding step shape 15 of the guide element 10 differs from the design in Figure 4. The corresponding feedthrough 16 for the cable feedthrough from the motor to the converter is therefore also provided in the first surface section of the guide element 10.

[0035] A modification of the guide element 10 is shown in Figure 9. Unlike in the embodiment shown in Figure 4, ribs 19 are formed at the end of the rear plate surface, serving as extensions of the cooling ribs 4c of the heat sink 4a of the electronics housing 4. This is evident in the sectional view shown in Figure 7, which initially shows the longitudinal ribs 4c of the heat sink 4a of the electronics housing 4, which are continued at the drive-side end by the ribs 19 of the guide element 10. The ribs 19 formed on the guide element 10 have an initial section running parallel to the motor axis and are then angled outwards by 90 degrees. The air flow 8 in the flow channel can thus be discharged to the outside.

Claims

Claims 1. Electric drive unit for a pump, in particular for a centrifugal pump, comprising an electric drive motor and an electronics housing (4) mounted circumferentially on the housing (1) of the drive motor, which electronics housing contains the necessary electronics for speed control of the motor and has a heat sink (4a) on its underside facing the drive motor, wherein at least one fan is provided which generates a cooling air flow flowing circumferentially around the outside of the motor, characterized in that at least one guide element (10) designed as a separate component is introduced between the electronics housing (4) and the motor housing (1), which guide element branches off a partial air flow (8) of the cooling air flow generated by the fan and, together with the heat sink (4a) of the electronics housing (4), forms a flow channel for the partial air flow (8) for cooling the electronics in the electronics housing (4).

2. Electric drive unit according to claim 1, characterized in that the fan comprises at least one fan wheel (3) seated on one end of the motor shaft (1a) and the guide element (10) together with a front side on the The fan cover (2) attached to the drive motor and the heat sink (4a) of the electronics housing (4) form the flow channel for the partial air flow.

3. Electric drive unit according to one of the preceding claims, characterized in that the flow channel is a closed flow channel at least in sections, in particular immediately after the branch.

4. Electric drive unit according to one of the preceding claims, characterized in that the flow channel for the partial air flow (8) runs at least in sections parallel to the drive shaft (1 a) of the drive motor.

5. Electric drive unit according to one of the preceding claims, characterized in that the guide element (10) is plate-shaped and the plate surface extends between the motor housing (1) and the electronics housing (4) parallel to the drive shaft (1 a).

6. Electric drive unit according to claim 5, characterized in that at least two side walls (14) extend between the plate-shaped guide element (10) and the heat sink (4a) of the electronics housing (4) in order to laterally close off the flow channel, wherein the side walls (14) are an integral part of the guide element (10) or of the electronics housing (4) or of the heat sink (4a).

7. Electric drive unit according to one of the preceding claims, characterized in that the guide element (10) serves as a support for receiving and fixing the electronics housing (4) and / or comprises at least one recess for the passage of a fastening means for fastening the electronics housing (4) to the motor housing (1).

8. Electric drive unit according to one of the preceding claims, characterized in that the guide element (10) has a passage (16) for the electrical connection between the motor and the electronics housing or a receptacle (10) for a part of an electrical connector.

9. Electric drive unit according to one of the preceding claims, characterized in that the guide element (10) is designed in two or more parts, wherein the guide element (10) is constructed from different types of material, in particular a supporting and optionally air-guiding part of the guide element (10) consists of a different material than a part that only guides air.

10. Electric drive unit according to one of the preceding claims, characterized in that the guide element (10) is provided with one or more ribs (19) which extend from the surface of the guide element (10) in the direction of the electronics housing (4) and serve as additional air guide elements.

11. Electric drive unit according to claim 10, characterized in that at least some of the ribs (19) form a continuation of existing ribs (4c) of the heat sink (4a) of the electronics housing (4) in the longitudinal direction of the flow channel.

12. Electric drive unit according to claim 10 or 11, characterized in that one or more of the ribs (19) of the guide element (10) run obliquely to the drive shaft (1 a) in order to divert the air flowing in the flow channel to the side.

13. Electric drive unit according to one of claims 10 to 12, characterized in that the cooling fins (4c) of the heat sink (4a) of the electronics housing (4) run parallel to the drive shaft (1a) and the adjoining fins (19) of the guide element (10) cause a deflection of the partial air flow (8) by approximately 90° outwards.

14. Electric drive unit according to one of the preceding claims, characterized in that the distance between the plate surface of the plate-shaped guide element (10) running parallel to the housing underside and the underside of the electronics housing (4) varies, in particular the guide element (10) comprises one or more steps or shoulders (15).

15. Electric drive unit according to one of the preceding claims, characterized in that the guide element (10) has in the branching area a surface section (11) inclined relative to the drive shaft (1a) in order to deflect the branched air flow (8) in the direction of the electronics housing (4).

16. Electric drive unit according to claim 15, characterized in that the inclined surface section (11) merges into a surface section (12) perpendicular to the motor shaft (1a), wherein the vertical surface section (12) in particular comprises a recess (12a) corresponding to the outer contour of the motor housing (1) in order to connect the guide element (10) to the motor housing (1) in a sealing manner in the region of the branch.

17. Pump, in particular centrifugal pump, with an electric drive unit according to one of the preceding claims.

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