Electric motor

Abstract

The utility model relates to an electric motor. The electric motor comprises a stator (1); a rotor (3) surrounding the stator (1); a shaft (5) connected to the rotor (3) in a rotationally fixed manner; a housing having a first housing part (6) and a second housing part (7) which together enclose a motor compartment in which the stator (1) and the rotor (3) are arranged; a cooling channel (16) extending in an inner space surrounded by the stator (1), in which a first end of the shaft (5) is arranged in the motor compartment, a second end of the shaft (5) protrudes from the housing, and the first housing part (6) has an inner portion protruding into the stator (1). According to the utility model, it is assumed that an insert (20) is arranged in the internal space surrounded by the stator (1), and the insert and the internal part of the first housing part (6) jointly define at least one section of the cooling channel (16).

Description

Technical Field

[0001] The utility model relates to an outer rotor motor with an internal cooling stator. Background Art

[0002] The present invention is based on an electric motor, which is known from the technology of EP3091638B1, for example.

[0003] An outer rotor motor with an internally cooled stator, ie cooling channels extending through the interior space surrounded by the stator, enables high performance and a compact design. Utility Model Content

[0004] The object of the present invention is to demonstrate the manner in which an electric motor of the above-mentioned type can be produced without difficulty.

[0005] This object is achieved by means of the electric motor of the present invention. The present invention also has advantageous improvements.

[0006] According to the present invention, an electric motor is provided, which includes: a stator; a rotor, which surrounds the stator; a shaft, which is connected to the rotor in a rotationally fixed manner; a housing, which includes a first housing component and a second housing component that jointly enclose a motor compartment, and the stator and the rotor are arranged in the motor compartment; a first cooling channel section, which extends in an internal space surrounded by the stator; wherein a first end of the shaft is arranged in an engine compartment, a second end of the shaft protrudes from the housing, and the first housing component includes an internal portion protruding into the stator, wherein an insert is arranged in the internal space surrounded by the stator, and the insert and the internal portion of the first housing component together define at least one section of the first cooling channel section.

[0007] According to the electric motor of the present invention, the insert is positioned in the first housing component by means of a tongue and groove joint.

[0008] According to the electric motor of the present invention, the insert has a groove extending in the axial direction, and the tongue portion of the inner portion of the first housing component engages with the groove.

[0009] According to the electric motor of the present invention, the insert has a first rib extending in the axial direction, and the first cooling channel section extends along the first rib.

[0010] According to the electric motor of the present invention, the first rib extending in the axial direction extends along the entire length of the insert in the axial direction.

[0011] According to the electric motor of the utility model, wherein, the insert has at least one second rib extending along a circumferential direction, the first cooling channel section extends along the at least one second rib.

[0012] According to the electric motor of the utility model, wherein, the insert has a plurality of second ribs extending along a circumferential direction and arranged adjacent to each other, and a sub-section of the first cooling channel section extends between the plurality of second ribs.

[0013] According to the electric motor of the utility model, wherein, the sub-sections of the first cooling channel section are arranged one after another along a flow direction.

[0014] According to the electric motor of the utility model, wherein, the sub-sections of the first cooling channel section extend side by side along an axial direction in the inner space.

[0015] According to the electric motor of the utility model, wherein, the first cooling channel section has a plurality of sub-sections connected in series, and the plurality of sub-sections extend side by side along a circumferential direction in the inner space.

[0016] According to the electric motor of the utility model, wherein, the insert is covered by a cooling plate, the first cooling channel section extends along a lower face of the cooling plate, and an upper face of the cooling plate abuts against electronic components of control electronics.

[0017] According to the electric motor of the utility model, wherein, the insert surrounds an annular space, and a first end of the shaft is arranged in the annular space.

[0018] In the electric motor according to the utility model, an insert is arranged in an inner space surrounded by a stator, which insert jointly defines at least one section of a cooling channel with an inner portion of a housing component. The insert has recesses on its outer surface to form the section of the cooling channel and is then inserted into a suitable opening in the housing component, and the insert can be produced cost-effectively. In particular, the cost is lower than the cost of forming a channel inside the housing component, for example, using a lost foam casting process. Furthermore, the insert can be made of a material different from that of the housing component, for example, made of plastic.

[0019] The housing component jointly defining the section of the cooling channel with the insert has an inner portion that protrudes into the stator, for example, into a central opening of an annular stack of stator laminations. The inner portion in turn has an opening for the insert to be inserted therein. Thus, the housing component delimits the cooling channel on the radially outer side in the inner space surrounded by the stator. The cooling channel can be delimited radially inward and laterally by the insert.

[0020] An advantageous refinement of the present invention provides that the insert is positioned in the housing component by means of a tongue-and-groove joint. This allows for effortless positioning of the insert relative to the housing component at its rotational angle. The tongue of the tongue-and-groove joint can be formed on the housing component or on the insert. However, generally speaking, it is preferred to provide the tongue of the tongue-and-groove joint on the housing, as this reduces the thickness of the wall in contact with the stator and thus allows for better thermal coupling of the cooling channel to the stator. The groove of the tongue-and-groove joint can extend over the entire axial length of the insert. However, in many cases, a short groove at one axial end of the insert is sufficient.

[0021] Another advantageous development of the invention provides that the insert surrounds an annular space in which one end of the shaft is arranged. Advantageously, the cooling channel defined by the insert and the housing part can also be used to cool the shaft bearing arranged in the annular space.

[0022] Another advantageous improvement of the present invention provides that the insert has a first rib extending in the axial direction, and the cooling channel extends along the first rib. In this way, the mechanical stability of the insert can be advantageously improved.

[0023] Another advantageous refinement of the present invention provides that the insert is covered by a cooling plate, with cooling channels extending along the lower surface of the cooling plate, and the upper surface of the cooling plate resting against the electronic components of the control electronics. In this way, the cooling channels can also advantageously be used to cool one or more electronic components, such as power transistors used to switch the power supply to the stator winding. The cooling plate can have protrusions on its lower surface that protrude into the cooling channels. The cooling channels can extend along the lower surface of the cooling plate in the flow direction and then open into the interior space surrounded by the stator, or vice versa, that is, the cooling channel section on the lower surface of the cooling plate is located downstream of the cooling channel section in the interior space surrounded by the stator. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Further details and advantages of the present invention are explained with reference to examples of embodiment and the accompanying drawings. Identical and corresponding parts are marked with corresponding reference numerals. In the drawings:

[0025] Figure 1 shows a cross-sectional view of an example embodiment of an electric motor according to the present invention;

[0026] Figure 2 The three sections defining the cooling passages of the electric motor are shown;

[0027] Figure 3 shows a schematic representation of another embodiment example of an insert forming a cooling channel design in the interior space surrounded by the stator;

[0028] Figure 4 shows a schematic representation of another embodiment example of an insert forming a cooling channel design in the interior space surrounded by the stator;

[0029] Figure 5 shows a schematic representation of another embodiment example of an insert forming a cooling channel design in the interior space surrounded by the stator;

[0030] Figure 6 A schematic representation showing an example of the course of cooling channels in the interior space surrounded by the stator;

[0031] Figure 7 shows a schematic representation of another example of the course of cooling channels in the interior space surrounded by the stator;

[0032] Figure 8 a schematic representation showing another example of the course of cooling channels in the interior space surrounded by the stator; and

[0033] Figure 9 A schematic representation of another example of the course of cooling channels in the interior space surrounded by the stator is shown. DETAILED DESCRIPTION

[0034] Figure 1 The electric motor shown comprises a stator 1 with a stator winding 2, a rotor 3 with permanent magnets 4, and a shaft 5 connected to the rotor 3 in a rotationally fixed manner (e.g., by means of a screw connection or welding). The rotor 3 and the stator 1 are enclosed in a motor compartment defined by a first housing part 6 and a second housing part 7. The second housing part 7 has an opening through which the shaft 5 protrudes.

[0035] The first housing part 6, together with the third housing part 8, defines an electronics compartment, in which a circuit board 9 with control electronics is arranged. The motor compartment and the electronics compartment are separated from each other by a wall 10 of the first housing part 6. The printed circuit board 9 faces this wall 10, i.e., is oriented substantially at right angles to the longitudinal axis of the shaft 5. The motor compartment and the electronics compartment are sealed from each other. The cables connecting the stator winding 2 to the printed circuit board 9 of the control electronics are routed through a sealed opening in the wall 10 of the first housing part 6.

[0036] The first housing component 6 has an inlet 11 and an outlet 12 for the coolant. The cooling channel leading from the inlet 11 to the outlet 12 comprises a first cooling channel section 16 for cooling the stator 1 and a second cooling channel section 15 for cooling electronic components 17 of the control electronics. The first cooling channel section 16 and the second cooling channel section 15 are connected in series. In the illustrated embodiment, the second cooling channel section 15 for cooling the electronic components 17 is arranged upstream of the first cooling channel section 16 for cooling the stator 1. However, it is also possible to allow the flow to pass through the second cooling channel section 15 only after passing through the first cooling channel section 16.

[0037] A first cooling channel section 16 for cooling stator 1 extends within the interior space surrounded by stator 1. Consequently, this first cooling channel section 16 is also bounded by wall 10, which separates the motor compartment from the electronics compartment. In the illustrated embodiment, wall 10 forms an annular space surrounded by stator 1, into which insert 20 is inserted, which together with wall 10 defines first cooling channel section 16.

[0038] First housing component 6 carries a cooling plate 18, along whose lower face coolant flows during operation. For example, cooling plate 18 and wall 10 (which separates the engine compartment from the electronics compartment) can together define the beginning and end sections of a cooling channel, and in particular, a second cooling channel section 15 for cooling electronic components 17 of the control electronics. One or more electronic components 17 of the control electronics rest against the upper face of cooling plate 18. To improve heat dissipation, cooling plate 18 can have protrusions 19 on its lower face that protrude into second cooling channel section 15.

[0039] Figure 2 Three components are shown that together define a cooling channel, namely a first housing part 6, an insert 20, and a cooling plate 18. The first housing part 6 has an inner portion that projects into the stator 1 and forms a receiving space for the insert 20. In the embodiment example shown, this receiving space is an annular space surrounding the end section of the shaft 5 and the first and second bearings 21, 22 of the shaft 5.

[0040] The insert 20 can be positioned in the first housing part 6, for example, by means of a tongue-and-groove joint. The insert 20 has a first rib 23 extending in the axial direction, along which the cooling channel runs. This first axial rib 23 has the effect of reinforcing the insert and extends over the entire axial length of the insert 20.

[0041] In the illustrated embodiment, the insert 20 has a plurality of second ribs 24 extending circumferentially, along which the cooling channels extend. Cooling channel segments extend circumferentially between these second ribs 24, which are arranged parallel to one another. These segments are arranged one behind the other in the flow direction. Consequently, the cooling channels extend without branches in the interior space.

[0042] Figure 2 The illustrated insert 20 defines two sub-segments (both connected in series) extending in the circumferential direction of the first cooling channel segment 16. The number and shape of the sub-segments of the first cooling channel segment 16 may vary.

[0043] Figure 3 A schematic representation of another embodiment example of an insert 20 forming a design for a first cooling channel segment 16 for stator cooling is shown. In this embodiment example, the cooling channel segment for stator cooling branches into a plurality of subsegments connected in parallel; these subsegments are defined by second ribs 24 extending parallel to one another in the circumferential direction. First ribs 23 extending in the axial direction over the entire axial length of the insert 20 mechanically stabilize the insert 20 and separate the start and end sections of the subsegments from one another.

[0044] Figure 4 A schematic representation of another exemplary embodiment of an insert 20 for forming a design of a first cooling channel segment 16 for stator cooling is shown. In this exemplary embodiment, the insert has a plurality of first ribs 23 extending in the axial direction, with cooling channel subsegments extending in the axial direction between each first rib. These subsegments are connected in series; therefore, the cooling channel has no branches.

[0045] Figure 5 A schematic representation of another embodiment example of an insert 20 forming a design of a first cooling channel section 16 for stator cooling is shown. Figure 4 In an exemplary embodiment, the insert has a plurality of first ribs 23 extending in the axial direction, with cooling channel subsections extending axially between each of the first ribs. In this exemplary embodiment, the subsections have varying cross-sections. The axially extending subsections narrow toward one of their two axial ends.

[0046] Figure 6 Schematically, an example of the course of the first cooling channel segment 16 is shown. The first cooling channel segment 16 has no branches but has three sub-segments which extend parallel to one another in the circumferential direction.

[0047] Figure 7 The first cooling channel section 16 is schematically shown relative to Figure 3 The progression of the insert 20 is shown. Figure 8 The first cooling channel section 16 is schematically shown relative to Figure 4 The progression of the insert 20 is shown. Figure 9 The first cooling channel section 16 is schematically shown relative to Figure 5 The progression of the insert 20 is shown.

[0048] List of Reference Numerals

[0049] 1st stator

[0050] 2 stator winding

[0051] 3 rotors

[0052] 4 permanent magnets

[0053] 5-axis

[0054] 6 First housing component

[0055] 7 Second housing component

[0056] 8 Third housing component

[0057] 9 circuit boards

[0058] 10 walls

[0059] 11Entrance

[0060] 12 exits

[0061] 16 first cooling channel section

[0062] 15 Second cooling channel section

[0063] 17 Electronic components

[0064] 18 cooling plates

[0065] 19 protrusions

[0066] 20 inserts

[0067] 21 First Bearing

[0068] 22 Second bearing

[0069] 23 first rib

[0070] 24Second rib.

Claims

1. An electric motor comprising stator (1), a rotor (3), said rotor surrounding said stator (1), a shaft (5) connected to the rotor (3) in a rotationally fixed manner, A housing comprising a first housing part (6) and a second housing part (7) which together enclose a motor compartment in which the stator (1) and the rotor (3) are arranged, a first cooling channel section (16), which extends in an interior space surrounded by the stator (1), in, The first end of the shaft (5) is arranged in the engine compartment, the second end of the shaft (5) protrudes from the housing, and The first housing member (6) comprises an inner portion protruding into the stator (1), It is characterized in that An insert (20) is arranged in an interior space surrounded by the stator (1), which together with an inner part of the first housing component (6) defines at least one section of the first cooling channel section (16).

2. The electric motor according to claim 1, wherein The insert (20) is positioned in the first housing part (6) by means of a tongue and groove joint.

3. The electric motor according to claim 1, wherein The insert (20) has a groove extending in the axial direction, into which groove a tongue of the inner part of the first housing component (6) engages.

4. The electric motor according to claim 1, wherein The insert (20) has a first rib (23) extending in the axial direction, along which the first cooling channel section (16) extends.

5. The electric motor according to claim 4, wherein: The first rib (23) extending in the axial direction extends over the entire length of the insert (20) in the axial direction.

6. The electric motor according to claim 1, wherein The insert (20) has at least one second rib (24) extending in the circumferential direction, and the first cooling channel section (16) extends along the at least one second rib.

7. The electric motor according to claim 1, wherein The insert (20) has a plurality of second ribs (24) arranged adjacent to one another and extending in the circumferential direction, with subsections of the first cooling channel section (16) extending between the second ribs.

8. The electric motor according to claim 7, wherein: The subsections of the first cooling channel section (16) are arranged one after another along the flow direction.

9. The electric motor according to claim 7, wherein: Subsections of the first cooling channel section (16) extend side by side in the axial direction in the interior space.

10. The electric motor according to claim 7, wherein The first cooling channel section (16) has a plurality of subsections connected in series, and the plurality of subsections extend side by side in the circumferential direction in the inner space.

11. The electric motor according to claim 1, wherein The insert (20) is covered by a cooling plate (18), along the lower face of which the first cooling channel section (16) extends, and the upper face of which abuts against electronic components (17) of the control electronics.

12. The electric motor according to claim 1, wherein The insert (20) surrounds an annular space in which the first end of the shaft (5) is arranged.

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