Permanent magnet rotor

Abstract

The invention relates to a permanent magnet rotor (1) comprising at least one laminated core (2) formed from at least two partial cores (3, 4), wherein: the laminated core (2) has magnet-receiving pockets (5) in which permanent magnets (6) are received; the laminated core (2) has, in its center, a receptacle (7) for a motor shaft (8); each partial core (3, 4) is formed by stacking individual laminations (9); and at least one permanent magnet (6) protrudes out of the magnet-receiving pocket (5) in at least one axial direction.

Description

[0001] Title: Permanent magnet rotor

[0002] DESCRIPTION

[0003] The invention relates to a permanent magnet rotor according to claim 1.

[0004] Permanent magnet rotors are used as an important component in electric motors, which can drive fluid pumps, for example. Brushless BLDC motors are now frequently used in such applications. A well-known example is the use of permanent magnet rotors, in which pockets are provided within a laminated core stack (made of stacked and punched individual laminations) to accommodate and secure permanent magnets. Typically, the permanent magnets within the pockets are arranged so that their axial length is adapted to the axial length of a laminated core of the permanent magnet rotor or is shorter, thus protruding behind the laminated core.

[0005] For manufacturing reasons, the lamination stack always has a significantly higher tolerance range after punching than the permanent magnets. Permanent magnets positioned behind the lamination stack lead to a reduction in the magnetic flux. Furthermore, existing permanent magnet motors are limited in their design, especially with regard to the targeted design of the lamination stack, which makes customized configurations difficult. Furthermore, there is a lack of means for targeted flow through the components if the electric motor is used to drive fluid pumps, in which the motor interior is flooded with a medium. Optimal or targeted heat dissipation of the motor components is generally not possible.

[0006] The object of the present invention is to propose an improved permanent magnet rotor that overcomes the aforementioned disadvantages, in particular, enables a customizable design and increases the effectiveness of the magnetic flux. In addition, efficient heat dissipation via the medium is to be achieved.

[0007] This problem is solved by the features of claim 1 .

[0008] A permanent magnet rotor comprises at least one laminated core which is formed from at least two sub-packages, wherein the laminated core has magnet receiving pockets in which permanent magnets are received, wherein the laminated core has a receptacle for a motor shaft in its center, wherein each sub-package is formed by stacking individual laminated cores and wherein the permanent magnets protrude from the magnet receiving pockets in at least one axial direction.

[0009] By protruding (or sticking out, or protruding from the end face) at least one permanent magnet from the magnet receiving pocket in at least one axial direction (i.e., on one or both sides of the end faces of the permanent magnet rotor), a forced media flow and media turbulence are achieved in the motor. The protruding permanent magnets act like vane tabs on the permanent magnet rotor and ensure the media flow and media turbulence. This creates a defined turbulence and circulation effect similar to a paddle wheel pump. The circulation effect can be increased by having the rotor laminated core with continuous channels. It is also possible to have the permanent magnets protrude on both sides. With known permanent magnet rotors, in which the permanent magnets are flush with the laminated core, a circulation effect is not possible.The media flow can also be increased by incorporating fluid channels into the stator. In wet-running motors, it is advantageous to selectively circulate the medium surrounding the permanent magnet rotor to ensure better heat dissipation from the stator and any electronic components.

[0010] Ideally, all permanent magnets should protrude axially on a common (radial) plane. The height of the protrusion or the extension of the permanent magnets can be individually adapted to the size of the laminated core or to the two sub-cores, depending on the desired motor parameters. The permanent magnet rotor can be designed as an I-rotor, T-rotor, or V-rotor, and in most cases as an IPM (Internal Permanent Magnet) rotor or an SPM (Surface Permanent Magnet) rotor.

[0011] The back-EMF (back-electromotive force) constant of the motor can be increased by increasing the magnetic flux density by extending the permanent magnet rotor relative to the stator length, thus increasing motor power without increasing the overall dimensions of the motor itself. Since the rotor core is often stamped in the same process as the stator core, it is advisable for the permanent magnet rotor and stator to be the same length (i.e., the same number of individual laminations in the lamination core). If the permanent magnet rotor were longer than the stator, stator laminations would be left over as waste during the stamping process.

[0012] To increase the magnetic flux density despite this, the present invention only makes the magnets longer than the lamination stack. The lamination stack is capable of capturing and utilizing the magnetic flux of the protruding magnets. This allows the back EMF constant of the motor to be increased while maintaining the same lamination stack length for the permanent magnet rotor.

[0013] The motor shaft is pressed into a holder in the center of the laminated core after the two sub-packages are joined together. The laminated core can be overmolded with a plastic before or after the motor shaft is pressed in. The plastic overmold serves to protect the laminated core from corrosion in the medium. Alternatively, the laminated core can be provided with a corrosion-resistant coating. In a further development, the individual laminations according to a first embodiment have at least one magnet receiving pocket and at least one clamping tongue in the holder. The at least one clamping tongue can be flexibly aligned upwards or downwards in the axial direction when the permanent magnet is inserted. In addition, the at least one clamping tongue enables a force-fitting and form-fitting fastening of the permanent magnet in the magnet receiving pocket. For example, the permanent magnet can have a groove for a form-fitting connection.The advantage of this fastening method is that it eliminates the need for additives such as adhesives. Furthermore, it is also advantageous to dispense with a cover on the axial end faces of the laminated core, as the clamping tongues prevent the permanent magnets from falling out. It also eliminates the need to overmold the laminated core after the permanent magnets have been inserted.

[0014] Particularly preferably, at least one fluid channel (and / or fluid bore) is formed in the individual laminations. A fluid channel promotes the flow of the medium through the permanent magnet rotor, with at least one fluid channel being arranged at a distance from the motor shaft receptacle (e.g., arranged concentrically) and forming an axial flow in the lamination stack. In addition, at least one fluid channel is formed by a clearance fit of the permanent magnets and the at least one clamping tongue in the magnet receptacle pockets. Through the fluid channels and at least one fluid bore, media circulation takes place via these and an air gap between the permanent magnet rotor and a stator.

[0015] According to one embodiment, the individual laminations according to a second embodiment form the receptacle without interruption in their periphery. This means that the receptacle has no clamping tongues, interruptions, elevations, or the like. As a result, the receptacle of the individual lamination according to the second embodiment does not come into contact with the outer diameter of the shaft in its periphery. In a laminated core formed from individual laminations according to the second embodiment, the laminated core is overmolded with plastic after the shaft is pressed in. Alternatively, the shaft can be secured in the laminated core using fasteners (e.g., adhesives).

[0016] According to a further embodiment, the individual laminations according to a third embodiment form the receptacle with a larger radial diameter than in the second embodiment. This allows, for example, a type of recess to be formed in the lamination stack to accommodate a thrust washer or an additional bearing seat in this recess.

[0017] According to one design, each sub-package is identically designed. Each sub-package has the same number of individual sheets according to the respective (first, second, or third) design. Alternatively, each sub-package can have a different number of individual sheets with different design shapes.

[0018] According to a further advantageous embodiment, each sub-package is formed from a plurality of individual sheets according to a first embodiment.

[0019] However, it is also conceivable that each sub-package is formed from a plurality of individual sheets according to a second embodiment.

[0020] It is also conceivable that each sub-package is formed from a plurality of individual sheets according to a third embodiment.

[0021] Furthermore, it is possible that each sub-package is formed from a plurality of individual sheets according to a first and / or second and / or third embodiment.

[0022] The aforementioned designs allow for a customized construction of the subpackages through different combinations of individual laminations in any combination. This allows the lamination stack to be individually adapted to specific engine requirements.

[0023] In an alternative embodiment, at least one individual lamination has at least one lamination tab on at least one axial end face of the laminated core, extending axially from the laminated core. Within this example, the forced media flow and media turbulence can also be achieved by protruding lamination tabs instead of by protruding permanent magnets, which are formed, for example, from or on the first individual lamination during punching. The lamination tab(s) can be provided in addition to the protruding permanent magnet rotors and enable additional fixation of the protruding permanent magnet. The uppermost individual lamination can deviate from the punched cut of the other individual laminations.

[0024] According to a preferred embodiment of the invention, some of the permanent magnets can be accommodated in a first sub-package and some of the permanent magnets can be accommodated in a second sub-package, and the first sub-package and the second sub-package can be combined to form a complete and common laminated core. Some of the permanent magnets are inserted into the magnet receiving pockets in the punching direction of the individual sheets. This prevents the magnets on their surfaces from being damaged by the clamping tongues in the magnet receiving pockets. When the sub-packages are assembled, the second sub-package is also applied to the first sub-package in the punching direction to prevent damage to the permanent magnet. A further advantage of dividing the permanent magnets into two sub-packages is the easier magnetization of the permanent magnets in the respective sub-packages.In an alternative embodiment, it is also possible to mount all permanent magnets in the first or second sub-package and then attach the other sub-package to the magnets.

[0025] Particularly advantageous is the inclusion of a thrust washer on the motor shaft. This thrust washer enables smooth start-up of the permanent magnet rotor and limits its axial play. The thrust washer's radial dimensions correspond to (or are smaller than) the radially enlarged diameter of the third design described above.

[0026] In particular, the permanent magnet rotor can be used in an electric motor. This is preferably a BLDC motor. However, the invention is not intended to be limited in this respect, but rather to cover all possible types of usable motors. The permanent magnet rotor is particularly preferably used in a fluid pump. It is also conceivable to use the permanent magnet rotor in an electric drive for fluid pumps or for actuators or servomotors.

[0027] If the magnets are arranged in a T- or V-shape, there is an unused space in the center towards the shaft, which consists only of unusable sheet material.

[0028] To reduce the weight of the parts and improve space utilization, the rotor can be provided with recesses at both ends. This creates space for the arrangement of bearings, some of which extend into the permanent magnet rotor.

[0029] List of reference symbols

[0030] 1 permanent magnet rotor

[0031] 2 sheet packages

[0032] 3 sub-package

[0033] 4 partial packages

[0034] 5 magnetic pocket

[0035] 6 permanent magnet

[0036] 7 Recording

[0037] 8 Motor shaft

[0038] 9 single sheets

[0039] 10a clamping tongue

[0040] 10b clamping tongue

[0041] 11 Fluid bore

[0042] 12 thrust washer

[0043] 13 sheet metal tab

[0044] 14 Front side

[0045] A First embodiment

[0046] B Second embodiment

[0047] C Third embodiment

[0048] U circumference

[0049] The invention is explained in more detail below using exemplary embodiments with reference to the attached schematic drawings.

[0050] Showing:

[0051] Fig. 1 is a perspective view of a permanent magnet rotor according to an embodiment;

[0052] Fig. 2 is a sectional view of a permanent magnet rotor according to Fig. 1;

[0053] Fig. 3 is a further sectional view of a permanent magnet rotor according to Fig. 1;

[0054] Fig. 4a-c show detailed representations of individual sheets according to a first, second or third embodiment;

[0055] Fig. 5 is a perspective view of a permanent magnet rotor according to another embodiment.

[0056] Fig. 1 shows a perspective view of a permanent magnet rotor (1) according to one embodiment. The permanent magnet rotor (1) comprises at least one laminated core (2) which is formed from at least two sub-cores (3, 4). The laminated core (2) has magnet receiving pockets (5) in which permanent magnets (6) are received. The laminated core (2) has a receptacle (7) for a motor shaft (8) in its center. Each sub-core (3, 4) is formed by stacking individual laminated sheets (9), and at least one permanent magnet (6) protrudes from the magnet receiving pocket (5) in at least one axial direction. Each sub-core (3, 4) is identically designed. Alternatively, however, it is also possible to design each sub-core differently. A thrust washer (12) is mounted on the motor shaft (8). Alternatively, a bearing can also be mounted on the motor shaft (8).

[0057] Fig. 2 shows a sectional view of a permanent magnet rotor (1) according to Fig. 1. The permanent magnet rotor (1) comprises at least one laminated core (2) which is formed from at least two sub-packets (3, 4). The laminated core (2) has magnet receiving pockets (5) in which permanent magnets (6) are received. The laminated core (2) has a receptacle (7) for a motor shaft (8) in its center. Each sub-packet (3, 4) is formed by stacking individual laminated sheets (9), and at least one permanent magnet (6) protrudes from the magnet receiving pocket (5) in at least one axial direction. Each sub-packet (3, 4) is identical. Alternatively, however, it is also possible to design each sub-packet differently. A thrust washer (12) is received on the motor shaft (8). Alternatively, a bearing can also be received on the motor shaft (8).Each sub-package (3, 4) is formed from a plurality of individual sheets (9) according to a first (A), second (B), and third (C) embodiment. Alternatively, at least one sub-package (3, 4) can be formed from a plurality of individual sheets (9) according to a first (A) embodiment, a second (B), or a third (C) embodiment. Alternatively, at least one sub-package (3, 4) can be formed from a plurality of individual sheets (9) according to a first (A) and / or second (B) and / or third (C) embodiment. Thus, all conceivable combinations of the embodiments (A to C) of the individual sheets to form at least one sub-package (3, 4) are possible. The individual sheets (9) according to a first (A) embodiment have at least one clamping tongue (10a, 10b) in at least one magnet receiving pocket (5) and in the receptacle (7).The at least one clamping tongue (10b) clamps onto the motor shaft (8), and the at least one clamping tongue (10a) securely fastens the permanent magnet (6) in the magnet receiving pocket (5). The individual sheets (9) according to a second (B) embodiment form the receptacle (7) without interruption in their circumference (U). The individual sheets (9) according to a third (C) embodiment form the receptacle (7) with a larger radial diameter than in the second (B) embodiment (B).

[0058] Fig. 3 shows a further sectional view of a permanent magnet rotor (1) according to Fig. 1. The laminated core (2) is formed from two identically designed sub-packets (3, 4). Each sub-packet (3, 4) is formed from a plurality of individual laminations (9) according to a first (A), second (B), and third (C) embodiment. Alternatively, at least one sub-packet (3, 4) can be formed from a plurality of individual laminations (9) according to a first (A) embodiment, or according to a second (B), or according to a third (C) embodiment. Alternatively, at least one sub-packet (3, 4) can be formed from a plurality of individual laminations (9) according to a first (A) and / or second (B) and / or third (C) embodiment. All conceivable combinations of the embodiments (A to C) of the individual laminations to form at least one sub-packet (3, 4) are thus possible.Some of the permanent magnets (6) are housed in a first sub-package (3), and some of the permanent magnets (6) are housed in a second sub-package (4). The first sub-package (3) and the second sub-package (4) are assembled to form a laminated core (2). Alternatively, all of the permanent magnets (6) can be housed in the first or second sub-package (3, 4), and then the second sub-package (4) or the first sub-package (3) can be pushed or pressed onto all of the permanent magnets (6) and assembled to form a laminated core (2).

[0059] Fig. 4a-c show detailed representations of individual sheets (9) according to the first (A), second (B) or third (C) embodiment.

[0060] Fig. 4a shows the individual sheet (9) according to a first embodiment (A), which has a receptacle (7) for a motor shaft (8) (not shown here) in the center. At least one clamping tongue (10b) is formed in the receptacle (7), which clamps onto the motor shaft (8) when it is pressed in and fastens the motor shaft (8) in the laminated core (2) (not shown here) with a force and a form fit. For example, the permanent magnet can have a groove for a form fit connection. The individual sheet (9) has magnet receiving pockets (5) in which permanent magnets (6) are fastened. At least one clamping tongue (10a) is provided in at least one magnet receiving pocket (5), which holds the permanent magnet (6) in the magnet receiving pocket (5). At least one fluid channel (11) is formed in at least one magnet receiving pocket (5) in the individual sheets (9). The individual sheet (9) shown here is designed for a T-rotor.Alternatively, the individual sheet (9) can also be designed for a V-rotor or I-rotor, but preferably for an SPM rotor, or alternatively for an IPM rotor. In a further alternative, the individual sheet (9) itself can have at least one fluid channel (11) (not shown here).

[0061] Fig. 4b shows the individual sheet (9) according to a second embodiment (B), which has a receptacle (7) for a motor shaft (8) (not shown here) in the center. The receptacle (7) is designed to be uninterrupted around its circumference (U). The individual sheet (9) has magnet receiving pockets (5) in which permanent magnets (6) are fastened. At least one clamping tongue (10a) is provided in at least one magnet receiving pocket (5), which holds the permanent magnet (6) in the magnet receiving pocket (5). At least one fluid channel (11) is formed in at least one magnet receiving pocket (5) in the individual sheets (9). The individual sheet (9) shown here is designed for a T-rotor. Alternatively, the individual sheet (9) can also be designed for a V-rotor or I-rotor, but preferably for an SPM rotor, or alternatively for an IPM rotor.

[0062] Fig. 4c shows the individual sheet (9) according to a third embodiment (C), which has a receptacle (7) for a motor shaft (8) (not shown here) in the center. The receptacle (7) has a larger radial diameter than in the second embodiment (B). The receptacle (7) is also uninterrupted in its circumference (U). Due to the radially larger diameter of the receptacle (7), a type of recess can be formed in the laminated core, for example, in order to accommodate a thrust washer (12) or an additional bearing seat in this recess. At least one fluid channel (11) is formed in at least one magnet receiving pocket (5) in the individual sheets (9).

[0063] Fig. 5 shows a perspective view of a permanent magnet rotor according to a further embodiment. As in the previous examples, the permanent magnet rotor (1) comprises at least one laminated core (2) which is formed from at least two partial cores (3, 4). The laminated core (2) has magnet receiving pockets (5) in which permanent magnets (6) are received. As a further development of the invention, at least one individual sheet (9) has at least one sheet metal tab (13) on at least one axial end face (14) of the laminated core (2), which extends in the axial direction from the laminated core (2). In other words, a section of the individual sheet (9) is bent upwards by 90° after the punching process. The sheet metal tabs (13) can be arranged directly next to a magnet receiving pocket (5). It is possible to provide only one sheet metal tab (13), but sheet metal tabs (13) can be provided distributed over the entire circumference. In the example in Fig.5, each magnet receiving pocket (5) on the individual sheet (9) has a sheet metal tab. It is conceivable to provide axially protruding sheet metal tabs (13) on both axial end faces of the permanent magnet rotor (1). This advantageously further improves the fixation of the protruding permanent magnets and the forced media flow and turbulence.

Claims

PATENT CLAIMS 1. Permanent magnet rotor (1) comprising at least one laminated core (2) which is formed from at least two partial cores (3, 4), wherein the laminated core (2) has magnet receiving pockets (5) in which permanent magnets (6) are received, wherein the laminated core (2) has a receptacle (7) for a motor shaft (8) in its center, wherein each partial core (3, 4) is formed by stacking individual laminated cores (9) and wherein at least one permanent magnet (6) protrudes from the magnet receiving pocket (5) in at least one axial direction.

2. Permanent magnet rotor according to claim 1, wherein the individual sheets (9) according to a first embodiment (A) have at least one clamping tongue (10a, 10b) in at least one magnet receiving pocket (5) and in the receptacle (7).

3. Permanent magnet rotor according to claim 2, wherein in the individual sheets (9) at least one fluid channel (11) is formed in at least one magnet receiving pocket (5).

4. Permanent magnet rotor according to one of the preceding claims, wherein the individual sheets (9) according to a second embodiment (B) form the receptacle (7) in its circumference (U) without interruption.

5. Permanent magnet rotor according to one of the preceding claims, wherein the individual sheets (9) according to a third embodiment (C) form the receptacle (7) with a larger radial diameter than in the second embodiment (B).

6. Permanent magnet rotor according to one of the preceding claims, wherein each sub-package (3, 4) is identically designed.

7. Permanent magnet rotor according to one of the preceding claims, wherein each sub-package (3, 4) is formed from a plurality of individual laminations (9) according to a first embodiment (A).

8. Permanent magnet rotor according to one of the preceding claims, wherein each sub-package (3, 4) is formed from a plurality of individual laminations (9) according to a second embodiment (B).

9. Permanent magnet rotor according to one of the preceding claims, wherein each sub-package (3, 4) is formed from a plurality of individual laminations (9) according to a third embodiment (C).

10. Permanent magnet rotor according to one of the preceding claims, wherein each sub-package (3, 4) is formed from a plurality of individual laminations (9) according to a first (A) and / or second (B) and / or third embodiment (C).

11. Permanent magnet rotor according to one of the preceding claims, wherein at least one individual lamination (9) has at least one lamination tab (13) on at least one axial end face (14) of the lamination stack (2) which extends in the axial direction from the lamination stack (2).

12. Permanent magnet rotor according to one of the preceding claims, wherein a part of the permanent magnets (6) is accommodated in a first partial package (3) and wherein a part of the permanent magnets (6) is accommodated in a second partial package (4) and wherein the first partial package (3) and the second partial package (4) are joined together to form a laminated core (2).

13. Permanent magnet rotor according to one of the preceding claims, wherein a thrust washer (12) is received on the motor shaft (8).

14. Permanent magnet rotor according to one of the preceding claims, wherein the permanent magnet rotor (1) is used in an electric motor.

15. Permanent magnet rotor according to one of the preceding claims, wherein the permanent magnet rotor (1) is used in a fluid pump.

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