Electric motor with rotor structure to prevent defect due to stress caused by temperature change, and manufacturing process for this

Abstract

An electric motor with a rotor structure and a manufacturing process for it, wherein no stress occurs due to temperature changes and no manufacturing problems arise. Each permanent magnet does not contact the others, and a deformable gripping element is positioned between the end faces of the magnets. The gripping element is an elastically or plastically deformable element, and the thickness of the gripping element in the direction of the rotor's axis of rotation is determined such that the adjacent permanent magnets, bonded to a rotor core within a manufacturing temperature range of the rotor, do not contact each other at a lower limit of the electric motor's operating temperature.

Description

Background of the invention 1. Field of the invention

[0001] The present invention relates to an electric motor and a manufacturing method for it, wherein the electric motor has a rotor structure to prevent defects such as bending of the rotor and breakage of a magnet due to thermal stresses on a magnetic steel plate, a shaft and the magnet, etc., which make up the rotor. 2. Description of the related prior art

[0002] In general, the main components for constructing the rotor of a synchronous electric motor are a magnetic steel plate, a carbon steel shaft, and a permanent magnet. The rotor structure can include: an SPM (surface permanent magnet) structure, in which a permanent magnet is attached to a rotor surface; and an IPM (interior permanent magnet) structure, in which a permanent magnet is embedded in a magnetic electric plate.

[0003] In the prior art, an electric motor is required to have a high maximum output or maximum torque, but only a low moment of inertia. Therefore, when an electric motor is designed or manufactured, its rotor structure is usually configured to extend in the axial direction. In such an electric motor, a neodymium magnet (NdFeB) with a high magnetic force is often used. An adhesive is typically used to fix the neodymium magnet to a core structure in which magnetic steel plates are stacked. A one-component, thermosetting plastic adhesive is widely used as the adhesive.

[0004] To avoid stress on a rotor with a plurality of magnets, several techniques have been proposed. For example, Japanese unexamined patent disclosure (Kokai) No. 2002-78257 discloses a rotor with a permanent magnet and describes that "a motor of the invention has a plurality of poles and a rotor, wherein a gap is formed between adjacent permanent magnets of the poles. Even when the temperature is varied, the thermal stress between the permanent magnet and the rotor is reduced, thereby limiting detachment of the component." It further describes that "in the motor of the invention, the gap between adjacent permanent magnets is filled with an adhesive and spheres."By filling the gap between permanent magnets with the adhesive and the spheres with predetermined dimensions, the thickness between the adjacent permanent magnets can be kept constant, making it easy to control the size of the rotor.”

[0005] In contrast, Japanese unexamined patent disclosure (Kokai) No. 2011-205781 discloses an electric motor with a permanent magnet and describes how “when a permanent magnet is inserted into a magnet insertion cavity formed in a rotor core, thin rubbers are temporarily attached to the upper and lower ends in relation to the insertion direction of the magnet, and then the permanent magnets are inserted sequentially. After one or more magnets have been inserted to stack the magnets in the direction of rotation, the rotor core is attracted from its two ends in such a way that pressure is exerted on the thin rubber on the end of the magnet, thereby forming a rotor structure.”

[0006] In a rotor according to the prior art, in which a neodymium magnet is bonded and fixed to a rotor core with a stacked magnetic steel plate, a stress is generated due to the difference in linear expansion coefficients of the neodymium magnet and the iron forming the rotor. After the two components with different linear expansion coefficients are bonded by an impregnating agent (or adhesive), when the temperature is varied from the point at which the adhesive has cured, a difference arises between the axial lengths of the iron and the magnet, thereby generating a stress. The following defects can be generated due to this stress. – the adhesive used to glue the magnet breaks, and the magnet can detach. – the rotor can bend due to an unevenness in the adhesive. – the magnet can be broken. – a gap can form between the stacked magnetic steel plates.

[0007] Particularly in a rotor that is comparatively long in the axial direction, a large number of magnets are stacked in the axial direction, and the defects described above can occur seriously according to its axial length.

[0008] Fig. Section 11 specifically describes the problems described above in a rotor according to the state of the art. A rotor 50 , as in Fig. Figure 11 shows an IPM rotor and features a rotor core. 54 , which is created by stacking a ring-shaped magnetic steel plate 52 is formed, a multitude of permanent magnets 56 , which are located in the rotor core 54 are embedded, and two end plates 58 on which the magnetic steel plate 52 Clamp from both sides in the axial direction. Each permanent magnet 56The magnet is a neodymium magnet with an essentially smooth shape, and the shapes of the permanent magnets are identical. The permanent magnets are designed as a plate extending in the axial direction of the rotor, and the plate is inserted into a slot. 60 inserted, which extends in the axial direction and which is in the rotor core 54 is formed. A main surface of each permanent magnet 56 is attached to an inner surface of the slot 60 using a heat-curing plastic adhesive (or impregnating agent) 62 bonded.

[0009] From the state of the section (a) according to Fig. 11, when the temperature of the rotor core 54 (at least one section of the rotor) 54 near the adhesive 62 ) a curing temperature of the adhesive 62 Once reached, the magnetic steel plate expands. 52with a comparatively high linear expansion coefficient (for example, 12 × 10 –6 / K) in the essentially axial direction of the rotor 54 (in the horizontal direction) as shown in section (b) according to Fig. Figure 11 shows the axial size of the permanent magnet. 56 not significantly changed, since the permanent magnet has a linear coefficient of expansion. 56 in the axial direction is significantly small (in the case of the neodymium magnet -0.5 × 10 –6 / K). In such a state, the adhesive 62 healed, so that the permanent magnet 56 and the magnetic steel plate 52 be bonded.

[0010] Next, when the temperature of the rotor core 54 When the operating temperature of the electric motor is lowered to a lower limit, the magnetic steel plate retracts. 52in the essentially axial direction together. In this regard, since the magnetic steel plate 52 at the permanent magnets 56 Once bonded and fixed, a section of the magnetic steel plate extends 52 near the permanent magnet 56 not together, and a section of the magnetic steel plate retracts. 52 near the outer surface or the center of the rotor core 54 together when the temperature decreases. As a result, a load is created and a voltage is present in the rotor core. 54 as shown in section (c) according to Fig. 11 shown. Furthermore, as in section (d) according to Fig. As shown in section 11, due to the stress caused by the load, a fracture can occur. 64 in the magnetic steel plate 52 If this occurs, the rotor shaft may bend (not shown) and / or a break or damage may occur in the permanent magnet. 56 appear.

[0011] In the technique described in Japanese unexamined patent disclosure (Kokai) No. 2002-78257, a gap is formed between the permanent magnets such that no stress is generated by the load due to the series of magnets. However, when this technique is applied to an IPM structure, it is difficult to create a constant gap between the magnets, either structurally or in terms of its fabrication. Conversely, when the technique is applied to an SPM structure, it is necessary to position the permanent magnets while a template, etc., is used to create a constant gap between the magnets, and therefore a manufacturing difficulty arises.

[0012] Furthermore, the Japanese unexamined patent disclosure (Kokai) No. 2002-78257 describes how the adhesive is filled into the gap between the magnets and polyethylene or silicone rubber beads are added to the adhesive. However, it is difficult to reliably fill the gap between the magnets with the adhesive, as this process depends on the properties of the adhesive and the skill of the user. Furthermore, the process requires removing any adhesive that protrudes from the gap onto the magnet surface. Additionally, adding the beads to the adhesive can adversely affect its properties. Since the distribution density of the beads in the adhesive can be uneven, the adhesive effect can become unstable.

[0013] In contrast, in the structure of Japanese unexamined patent disclosure (Kokai) No. 2011-205781, an elastic thin plate is attached to a surface of the magnet, which is axially opposite, and a clamping force is exerted on the structure from its two axial ends by means of clamping plates, so that a compressive force is exerted on the elastic thin plate. However, in the structure of Japanese unexamined patent disclosure (Kokai) No. 2011-205781, adhesives are not used to fix the permanent magnets, and thus the structure is not intended to bear the load due to the difference in the linear expansion coefficients. Furthermore, the object of the invention of Japanese unexamined patent disclosure (Kokai) No.2011-205781 in preventing damage to the magnet when the magnet is inserted and fixed in the manufacturing process of the rotor, and thus does not solve the thermal stress defect. SUMMARY OF THE INVENTION

[0014] Thus, the object of the invention is to provide an electric motor with a rotor structure and a manufacturing method for it, wherein no stress due to a temperature change occurs and no manufacturing problem arises.

[0015] One embodiment of the invention provides for an electric motor comprising a stator and a rotor configured to rotate relative to the stator, the rotor comprising: a rotor core formed by stacking magnetic steel plates; a plurality of permanent magnets aligned in one direction of a rotational axis of the rotor, the permanent magnets being bonded and fixed to the magnetic steel plate by means of adhesives; and an engagement element positioned between the permanent magnets adjacent to one another in the direction of the rotational axis, the thickness of the engagement element being determined in the direction of the rotational axis such that adjacent permanent magnets bonded to the rotor core within a manufacturing temperature range of the rotor do not contact one another at a lower limit of an operating temperature of the electric motor.

[0016] In a preferred embodiment, the engagement element is elastically or plastically deformable.

[0017] In a preferred embodiment, the permanent magnets are bonded and fixed in a magnet insertion hole formed in the rotor core and extending in the direction of the axis of rotation.

[0018] In a preferred embodiment, the permanent magnets are bonded and fixed to a surface of the rotor core.

[0019] A further embodiment of the invention provides a manufacturing method for an electric motor comprising a stator and a rotor configured to rotate relative to the stator, wherein the method comprises the steps of: forming a rotor core by stacking magnetic steel plates; aligning a plurality of permanent magnets in the direction of a rotational axis of the rotor and fixing the permanent magnets to the magnetic steel plate by means of adhesives; and positioning an engagement element between the permanent magnets adjacent to one another in the direction of the rotational axis, wherein a thickness of the engagement element in the direction of the rotational axis is determined such that adjacent permanent magnets bonded to the rotor core within a manufacturing temperature range of the rotor do not contact one another at a lower limit of an operating temperature of the electric motor.

[0020] In a preferred embodiment, the method further comprises the step of further heating the rotor after the adhesives have cured, so that the gripping element melts and flows from between adjacent permanent magnets.

[0021] In a preferred embodiment, the method comprises the step of alternately inserting the permanent magnet and the gripping element into a magnet insertion hole formed in the rotor core.

[0022] In a preferred embodiment, the method comprises the step of prior adhesion of the gripping element to an end face of the permanent magnet that is opposite in the direction of the axis of rotation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above-described and further tasks, features and advantages of the invention will become more apparent through the following description of the preferred embodiments of the invention with reference to the accompanying drawings.

[0024] They show:

[0025] Fig. 1 a view of a schematic structure of an electric motor according to an embodiment of the invention;

[0026] Fig. 2 an axial cross-sectional view of a rotor of the electric motor according to Fig. 1;

[0027] Fig. 3 a view showing an example in which an engagement element positioned between permanent magnets is a sheet metal element;

[0028] Fig. 4 a view showing an example in which the gripping element is a silicon resin or a urethane foam that is applied to the permanent magnet,

[0029] Fig. 5 a view showing an example in which the intervention element consists of foamed polystyrene beads;

[0030] Fig. 6 a view showing an example in which the engagement element is a grooved metal or resin;

[0031] Fig. 7 a view which describes a manufacturing process of the rotor according to Fig. 2 describes;

[0032] Fig. 8 a view which proposes a further manufacturing process of the rotor according to Fig. 2 describes;

[0033] Fig. 9 a view that shows a function and effect of the rotor's engagement element according to Fig. 2 describes;

[0034] Fig. 10 a view of a schematic structure of an electric motor according to a further embodiment of the invention; and

[0035] Fig. 11 An axial cross-sectional view of a rotor of a prior art electric motor, comprising a section (a) showing a condition prior to curing of adhesives, a section (b) showing a condition in which the temperature of the rotor is increased to a curing temperature of the adhesives, a section (c) showing a condition in which the temperature of the rotor is decreased from the condition according to section (b) to a lower limit of an operating temperature of the motor, and a section (d) showing a condition in which part of the stacked magnetic steel plates is broken. DETAILED DESCRIPTION

[0036] Fig. Figure 1 shows a schematic diagram of an electric motor. 10 according to an embodiment of the invention. The rotor 10 features a rotor 14 , into which a wave 12 (i.e., a rotational axis) is inserted, a stator 18, which is created by stacking ring-shaped magnetic steel plates 16 is formed, and a case 22 up, which the rotor 14 and the stator 18 includes and the wave 12 by means of a condition 20 Rotatable. Since the components that are carried by the rotor 14 Since they are different and can be conventional, a detailed description of them is omitted.

[0037] Fig. 2 shows the rotor 14 of the electric motor 10 according to Fig. 1. The rotor 14 according to Fig. 2 is a rotor with an IPM structure in which permanent magnets are embedded. The rotor 14 features a rotor core 26 , which is created by stacking ring-shaped magnetic steel plates 24 is formed, a multitude of permanent magnets 28 , which are located in the rotor core 26 are embedded, and two end plates 30on which the magnetic steel plates enclose or clamp between them from both axial sides. For example, every permanent magnet 28 a neodymium magnet with a substantially flat shape, and preferably each magnet has the same shape. As in Fig. Shown in section 2 are the permanent magnets. 28 aligned in the direction of the axis of rotation (specifically, one end face of each permanent magnet faces each other to form a magnetic plate extending in the direction of the rotor's axis of rotation) and are inserted into a magnet insertion hole or slot 32 inserted, that or the in the rotor core 26 is formed and extends in the direction of the axis of rotation. Main surfaces 34 and 36 from any permanent magnet 28 are attached to an inner surface of the slot 32 using a heat-curing plastic adhesive (or impregnating agent) 38bonded. Every permanent magnet 28 does not contact the other, and a deformable intervention element is created. 40 positioned between the end faces of the magnets.

[0038] The intervention element 40 is an elastically or plastically deformable element, and the thickness of the engagement element 40 in the direction of the rotor's axis of rotation is determined in such a way that adjacent permanent magnets 28 , which are attached to the rotor core 26 Within a manufacturing temperature range of the rotor, the components bonded together do not contact each other at a lower limit of the operating temperature of the electric motor, as described below.

[0039] Fig. 3 to Fig. Figure 6 shows different examples of an intervention element. 40 First, it shows Fig. 3. An example in which the engagement element is an elastically or plastically deformable sheet-like element. 40aIt's like rubber or resin. The sheet-like element 40a is attached to the axial end surface of the permanent magnet 28 bonded using an adhesive, etc., and functions as the engagement element.

[0040] Fig. Figure 4 shows an example where the intervention element is a liquid resin. 40b It is a material that, after it has cured, exhibits elasticity, like rubber. The liquid resin 40b is applied to the axial end surface of the permanent magnet 28 using a spatula 42 etc. is applied and functions as the intervention element after it has healed.

[0041] Fig. Figure 5 shows an example in which the intervention element is made of elastically or plastically deformable spheres. 40c consists of, for example, expanded polystyrene. The beads 40c are attached to the axial end face of the permanent magnet 28 bonded by means of an adhesive, etc., and function as the interlocking element.

[0042] Fig. Figure 6 shows an example in which the engagement element is a grooved plate element. 40d This is formed by corrugating a resin or metal plate so that the plate has a certain elasticity. The corrugated plate element 40d is attached to the axial end surface of the permanent magnet 28 bonded using an adhesive, etc., and functions as the engagement element.

[0043] Regarding the examples according to Fig. 3 to Fig. 6. In addition, a resin with a comparatively low melting point that is higher than a curing temperature of the adhesive (i.e., the electric motor is not adversely affected at the melting point), a metal such as tin (which has a melting point of 232°C), or a metal with a low melting point (e.g., an alloy with a melting point of 138°C containing bismuth, tin, lead, and cadmium) can be used as the interlocking element.In other words, if an element is used that melts at a temperature higher than the curing temperature of the adhesive (or impregnating agent) in a process of heating and curing the adhesive, the interlocking element can be melted by further increasing the temperature after the adhesive has cured, such that the interlocking element flows between the permanent magnets, thereby forming a suitable gap or space between the permanent magnets.

[0044] Next, a manufacturing process for the motor with IPM structure, as described in Fig. 2 shown, with reference to Fig. 7 and Fig. 8 will be described. First, in the embodiment according to Fig. 7, the intervention element 40 first to an axial end of the permanent magnet 28 attached or applied, and the permanent magnet becomes 28 sequentially into the slot32 inserted into the stack of magnetic steel plates 24 (In the illustrated embodiment, five permanent magnets are placed in a slot) 32 inserted). Then a heat-curing plastic adhesive is applied between the inner surface of the slot. 32 and the main surface of the permanent magnet 28 impregnated, and the rotor core becomes 26 heated to the curing temperature of the adhesive or higher to secure the permanent magnet 28 to the rotor core 26 to bond and fix.

[0045] In the embodiment according to Fig. 8 becomes the intervention element 40 not pre-attached or applied to the axial end of the permanent magnet, as in Fig. 7 shown, but instead the permanent magnet 28 and the intervention element 40 alternating in the slot 32inserted. In this regard, it is not necessary to insert the intervention element. 40 at the permanent magnets 28 to add. Then, similar to the exemplary embodiment according to Fig. 7, a heat-curing plastic adhesive is applied between the inner surface of the slot 32 and the main surface of the permanent magnet is impregnated and becomes the rotor core 26 heated to the curing temperature of the adhesive or higher to secure the permanent magnet 28 to the rotor core 26 to bond and fix.

[0046] Next, the function of the intervention element will be described. 40 , that between the permanent magnets 28 is positioned, with reference to Fig. 9 will be described. A section (a) according to Fig. Figure 9 shows part of the rotor core 26 before the adhesive has cured 38 , that between the inner surface of the slot 32 and the main surface of the permanent magnet28 is impregnated (generally at normal temperature). From the state of section (a) according to Fig. 9, when the temperature of the rotor core 26 (at least one periphery of the adhesive) 38 ) to the curing temperature of the adhesive 38 As the pressure increases, the magnetic steel plate expands. 24 with a comparatively high linear expansion coefficient (e.g. 12 × 10 –6 / K) mainly in the direction of the axis of rotation (or in the left-right direction), while the permanent magnet 28 with a significantly lower linear expansion coefficient relative to the magnetic steel plate 24 (e.g. –0.5 × 10 –6 / K in the case of a neodymium magnet) changes little in its dimensions in the axial direction, as in a section (b) according to Fig. 9 shown. In the state of the cut (b) according to Fig. 9 the adhesive 38healed, and then the permanent magnet 28 and the magnetic steel plate 24 bonded together.

[0047] Then, when the temperature of the rotor core 26 When the operating temperature of the electric motor is lowered to a lower limit, the magnetic steel plate retracts. 24 mainly in the direction of the axis of rotation, while the permanent magnet 28 It changes little in its extent. Furthermore, since the permanent magnet 28 to the magnetic steel plate 24 bonded and fixed, as in a section (c) according to Fig. Figure 9 shows an axial distance between permanent magnets. 28 reduced (more precisely, a distance between the axial end faces of adjacent permanent magnets) 28 (is reduced). Furthermore, the deformable engagement element 40 between the end faces of the permanent magnets 28When applied as described above, a voltage acts on the rotor core. 26 through the pressure deformation of the engagement element 4 in the axial direction, whereby the in Fig. The disadvantage shown in point 11 can be avoided. Furthermore, the thickness of the intervention element is... 40 determined in such a way that adjacent permanent magnets 28 do not contact each other at the lower limit of the operating temperature of the electric motor, as shown in section (c) according to Fig. 9 shown.

[0048] Although the magnetic steel plate 24 to the same extent in the radial direction of the rotor (the vertical direction in Fig. 9) due to the temperature change, the thermal stress in the radial direction of the rotor does not pose a problem, since the permanent magnet 28a relatively high linear expansion coefficient in one magnetization direction (or in one direction of slight magnetization), i.e., in the radial direction of the rotor (e.g., 6.5 × 10 –6 / K in the case of a neodymium magnet).

[0049] Fig. Figure 10 shows a further embodiment of a rotor of an electric motor according to the invention, i.e. a rotor 114 with SPM structure, in which permanent magnets are attached to a surface of the structure. The rotor 114 features a rotor core 126 , which is created by stacking ring-shaped magnetic steel plates 124 is formed, a multitude of permanent magnets 128 , which are located in the rotor core 126 are embedded, and two end plates 130 on, which the magnetic steel plates 124 to enclose or clamp between themselves from both axial sides. For example, every permanent magnet 128a neodymium magnet with a substantially smooth shape, and preferably each magnet has the same shape. As in Fig. As shown in 10, the permanent magnets are 128 aligned in the direction of the axis of rotation (specifically, one end face of each magnet faces the other to form a curved magnetic plate extending in the direction of the rotor's axis of rotation), and are attached to an outer surface of the rotor core 126 bonded. In detail, under main areas 134 and 136 from each permanent magnet 128 , the concave main surface 136 to the essentially cylindrical side surface of the rotor core 126 using a heat-curing plastic adhesive 138 bonded. Every permanent magnet 128 does not contact the other, and a deformable intervention element 140 is positioned between the end faces of the magnets.

[0050] When the permanent magnets stick 128 to the outer surface of the rotor core 126 can accommodate a variety of permanent magnets 26 , which are connected to each other via the intervention element 140 are connected between each other (as by reference signs) 128a according to Fig. 10 shown), to the rotor core 126 can be bonded. Alternatively, any permanent magnet can be used. 128 , which is the intervention element 140 where one end has, sequentially to the rotor core 126 be bonded.

[0051] The intervention element 140 and its function can be the same as that of the intervention element 40, which was described from the perspective of the rotor with IPM structure, and therefore a detailed description of it will be omitted. As such, the invention can be applied to both the IPM structure, in which the permanent magnet is embedded in the rotor core, and the SPM structure, in which the permanent magnet is bonded and fixed to the outer surface of the rotor core.

[0052] Although the permanent magnet in the exemplary embodiment is described as a neodymium magnet, the invention itself is not limited. For example, the permanent magnet could be a ferrite magnet. The invention can be applied in a case where the linear coefficients of thermal expansion of the permanent magnet and the magnetic steel (iron) plate differ in the direction of the axis of rotation.

[0053] According to the invention, even if the temperature of the rotor is lowered from the temperature at which the permanent magnet is bonded to the rotor, so that a difference in the axial direction occurs between the magnetic steel plate and the permanent magnet, the difference is compensated for by the deformation of the engagement element that is positioned between the permanent magnets, thereby avoiding the disadvantage, such as damage to the rotor.

[0054] In the invention it is not necessary to provide a gap between aligned magnets as in the prior art, and the magnets are aligned in the axial direction and bonded to the rotor surface in the same SPM structure.

[0055] Therefore, it is not necessary to intentionally create a gap between the magnets. Furthermore, it is not necessary to use a special adhesive. Moreover, when attaching the permanent magnet, it is only necessary to bond the permanent magnet to the rotor core; thus, it is not necessary to bond the magnets to each other. Therefore, the adhesive does not spread or protrude, and it is not necessary to wipe away any excess adhesive.

[0056] The element that exists between the aligned permanent magnets, at least until the adhesive has cured, is removed during the manufacturing process, creating a space between the magnets. Therefore, no stress or strain remains, even if the rotor has a relatively long axial length, and thus no rotor bending occurs. Furthermore, breakage of the permanent magnet and the adhesive is prevented. QUOTES INCLUDED IN THE DESCRIPTION

[0057] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0058] JP 2002-78257 [0004, 0011, 0012] JP 2011-205781 [0005, 0013]

Claims

[1] Electric motor ( 10 ), comprising a stator ( 18 ) and a rotor ( 14 ), which is configured to be rotated relative to the stator, where the rotor ( 14 ) includes: a rotor core ( 26 ), which is created by stacking magnetic steel plates ( 24 ) is formed; a large number of permanent magnets ( 28 ), which are in one direction of a rotational axis of the rotor ( 14 ) is aligned, with the permanent magnets attached to the magnetic steel plate ( 24 ) are bonded and fixed by means of adhesives; and an intervention element ( 40 ), which is between the permanent magnets ( 28 ) is positioned adjacent to each other in the direction of the axis of rotation, wherein a thickness of the engagement element ( 40 ) in the direction of the axis of rotation is determined such that adjacent permanent magnets ( 28 ), which are attached to the rotor core (26 ) within a manufacturing temperature range of the rotor ( 14 ) are bonded, do not contact each other at a lower limit of the operating temperature of the electric motor. [2] Electric motor according to claim 1, characterized in that the engagement element ( 40 ) is elastic or plastically deformable. [3] Electric motor according to claim 1 or 2, characterized in that the permanent magnets ( 28 ) in a magnetic insertion hole ( 32 ) are bonded and fixed, which is in the rotor core ( 26 ) is formed and extends in the direction of the axis of rotation. [4] Electric motor according to claim 1 or 2, characterized in that the permanent magnets ( 28 ) to a surface of the rotor core ( 26 ) are bonded and fixed. [5] Manufacturing process of an electric motor ( 10 ), which has a stator ( 18 ) and a rotor ( 14) includes, which is configured to be rotated relative to the stator, the procedure includes the following steps: Forming a rotor core ( 26 ) by stacking magnetic steel plates ( 24 ); Aligning a large number of permanent magnets ( 28 ) in one direction of a rotor's axis of rotation ( 14 ) and fixing the permanent magnets ( 28 ) to the magnetic steel plate ( 24 ) using adhesives; and Positioning an intervention element ( 40 ) between the permanent magnets ( 28 ), which are adjacent to each other in the direction of the axis of rotation, wherein a thickness of the engagement element ( 40 ) in the direction of the axis of rotation is determined such that adjacent permanent magnets ( 28 ), which are attached to the rotor core ( 26 ) within a manufacturing temperature range of the rotor ( 14) are bonded, do not contact each other at a lower limit of the operating temperature of the electric motor. [6] Manufacturing method according to claim 5, characterized in that the method further comprises the step of further heating the rotor ( 14 ) after the adhesives have cured, so that the intervention element ( 40 ) melts and separates between adjacent permanent magnets ( 28 ) flows. [7] Manufacturing method according to claim 5 or 6, characterized in that the method comprises the step of alternating insertion of the permanent magnet ( 28 ) and the intervention element ( 40 ) into a magnetic insertion hole ( 32 ), which is in the rotor core ( 26 ) is trained. [8] Manufacturing method according to claim 5 or 6, characterized in that the method comprises the step of prior adhesion of the engagement element ( 40) to an end face of the permanent magnet ( 28 ), which is opposite in the direction of the axis of rotation.