Electric machine for vehicle

Abstract

The utility model relates to a motor (100) for a vehicle, the motor is provided with a stator (101) comprising a stator main body (102), the stator main body (102) comprises alternating stator teeth (112) and stator slots (114), and the stator slots are provided with conductor elements (116) arranged therein. Wherein a yoke portion (118) having a radially extending yoke height (120) is formed on the stator body (102) radially outward of the stator slots (114), where the stator body (102) comprises a stator outer radius (122), and where a ratio (v1) of the yoke height (120) to the stator outer radius (122) is between 0.18 and 0.26.

Description

Technical Field

[0001] The utility model relates to a motor used for a vehicle. Background Art

[0002] US 9,755,463 B2 discloses an electric machine having a first carrier and a second carrier, wherein the first carrier has an electromagnetic element and the second carrier has an electromagnetic element, wherein the second carrier is movable relative to the first carrier. The electric machine has a high current density but is complex in construction.

[0003] DE 10 2018 112 347 A1 discloses an electric machine with a stator and a stator laminated core, wherein the conductor elements are arranged in the stator laminated core and are cooled by coolant channels. This is advantageous for high current densities, but there are also possibilities for optimization here. Utility Model Content

[0004] The problem solved by the utility model is to provide an improved motor. It is expected to provide a motor with relatively high current density and improved efficiency by means of simple construction.

[0005] This problem is solved by the motor described below.

[0006] The motor is used for a vehicle. The motor comprises a stator having a stator body (stator lamination stack), wherein the stator body (along the circumferential direction) alternately comprises stator teeth and stator slots, wherein one or more conductor elements are arranged in the stator slots, respectively. A yoke portion having a radially extending yoke height is formed on the stator body radially outside the stator slots and the stator teeth. The stator body has a stator outer radius. A ratio v1 of the yoke height to the stator outer radius is between 0.18 and 0.26 (0.18≤ratio v1≤0.26).

[0007] A relatively large yoke height contributes to a high efficiency of the electric machine, which is achieved by an increased lamination ratio in the stator and thus a relatively high current density. This leads to reduced iron losses and thus increases the efficiency of the electric machine.

[0008] In particular, the ratio v1 of the yoke height relative to the stator outer radius may be between 0.20 and 0.24 (0.20≤ratio v1≤0.24), further preferably between 0.21 and 0.23 (0.21≤ratio v1≤0.23). In a specific example, the ratio v1 of the yoke height relative to the stator outer radius may be 0.22 (ratio v1=0.22). By designing the stator body using these ratios, the efficiency of the machine can be further optimized.

[0009] In particular, the electric machine is a traction motor for a vehicle. The electric machine is configured and / or intended to drive, preferably drive alone, the vehicle (traction drive). The vehicle is in particular a semi-electric or fully electric motor vehicle (electric vehicle), in particular a passenger car, such as a sports car. The conductor elements are in particular stator turns.

[0010] The yoke part forms a closed annular part of the stator body along the circumferential direction. The stator body extends along the axial direction. The stator teeth and the stator slots also extend along the axial direction or parallel to the axial direction.

[0011] Preferably, the stator body may have a stator inner radius, wherein the ratio v2 of the stator inner radius to the stator outer radius is between 0.61 and 0.69 (0.61≤ratio v2≤0.69). Thus, a relatively low stator inner radius is obtained. This in turn allows the lamination share in the stator to be increased, which increases efficiency. Due to the low stator inner radius, the rotor outer radius can be kept low, which reduces friction losses and thus increases efficiency. The stator outer radius can also be kept relatively low.

[0012] In particular, the ratio v2 of the stator inner radius to the stator outer radius may be between 0.63 and 0.67 (0.63≤ratio v2≤0.67), further preferably between 0.64 and 0.66 (0.64≤ratio v2≤0.66). In a specific example, the ratio v2 of the stator inner radius to the stator outer radius may be 0.65 (ratio v2=0.65). Efficiency may be further optimized by constructing the stator body with these ratios.

[0013] Preferably, the stator outer radius may be between 105 mm and 142.5 mm (millimeters). This helps to relatively reduce friction losses and improve efficiency. In particular, the stator outer radius may be between 115 mm and 132.5 mm, and further preferably between 120 mm and 127.5 mm. In a specific example, the stator outer radius may be 122.5 mm.

[0014] Preferably, two or three stator slots can be provided or passed through each pole and each strand (one stator turn) on the stator body. Several conductor elements can form one strand or the strand (one stator turn). In other words, the number of holes (number of stator slots per pole and each strand) is q=2 or q=3. This results in efficiency advantages and a compact construction space.

[0015] Preferably, in particular when each pole and each strand has two stator slots, the ratio v3 of the stator tooth width to the stator slot width may be between 0.50 and 0.75 (0.50≤ratio v3≤0.75). In particular, in particular when each pole and each strand has two stator slots, the ratio v3 may be between 0.55 and 0.70 (0.55≤ratio v3≤0.70), further preferably between 0.60 and 0.65 (0.60≤ratio v3≤0.65).

[0016] Alternatively, in particular when each pole and each strand has three stator slots, the ratio v3 of the stator tooth width to the stator slot width can be between 1.05 and 1.50 (1.05≤ratio v3≤1.50). In particular, in particular when each pole and each strand has three stator slots, the ratio v3 can be between 1.15 and 1.40 (1.15≤ratio v3≤1.40), further preferably between 1.20 and 1.35 (1.20≤ratio v3≤1.35), and further preferably between 1.25 and 1.30 (1.25≤ratio v3≤1.30). In a specific example, the ratio v3 can be equal to 1.27. With the ratio v3, a large stator tooth width can be achieved, while the stator slot width is relatively low. Therefore, an increase in the lamination share can be achieved, which reduces iron losses. This is accompanied by a high current density.

[0017] For example, by fine-tuning the ratio v3, the motor can be configured to achieve more than 40A / mm at maximum current. 2 (ampere / square millimeter), preferably greater than 45A / mm 2 , further preferably at 45A / mm 2 With 60A / mm 2 Between, especially at 50A / mm 2 With 60A / mm 2 The maximum current density between .

[0018] Preferably, the electric machine can have a pole pair number p of p=3 (3 pole pairs, i.e. 6 poles in total). Thus, a sufficiently high number of pole pairs can be achieved in a relatively compact construction space. The relatively low frequency of the pole pair number p=3 provides efficiency advantages, in particular in combination with the geometric ratios given above.

[0019] Preferably, at the radially inner end of the stator teeth, a respective tooth head may be formed, the cross section of the tooth head being enlarged relative to the stator tooth (or the cross section of the stator tooth outside the tooth head). This is often advantageous for higher efficiency and high current density. The tooth heads may each extend radially along a defined tooth head height.

[0020] Preferably, the can can be arranged radially inside the stator body adjacent to the stator body, wherein the can can cover the stator slots when viewed in the radial direction, i.e. radially inwardly. Thus, a sealing of the stator space relative to the rotor space can be provided. The stator slots can be formed to be open radially inwardly and covered by the can. For example, the can can be abutted against the stator teeth or their tooth heads. The can is manufactured, for example, as a preferably fiber-reinforced plastic tube. However, the can can also be made of an elastic and / or flexible material fixed to the stator body. For example, the can can be configured as a radial lining of the stator.

[0021] The electric machine comprises a rotor that electromagnetically cooperates with a stator, in particular runs dry. The rotor has an outer rotor radius that is smaller than the inner stator radius by a radial air gap height (air gap). The can can also be arranged in the air gap. In particular, a clearance fit can be formed between the can and the rotor, and the rotor can be electromagnetically driven radially inside the stator.

[0022] The can seal the rotor relative to the stator so that the rotor is not wetted by a cooling medium that may be present on the stator. Fluid friction with the cooling medium can be avoided by the rotor, which is in particular dry-running. An air gap can be formed between the can and the rotor so that the rotor, which is rotatable relative to the stator, does not rub against the can. The rotor can be connected in particular to a drive train of a motor vehicle so that the motor vehicle can be driven purely electrically with the aid of an electric machine.

[0023] Preferably, the stator body may be formed by a lamination stack, wherein several stator laminations are arranged one after another in the axial direction, wherein the stator laminations each have a lamination thickness of 0.25 mm or less. This helps the motor to operate efficiently at high power. In particular, the stator laminations may have a lamination thickness of 0.10 mm to 0.25 mm.

[0024] In particular, the stator body can be made from a lamination stack, wherein several stator laminations made from sheet metal, in particular by stamping, are arranged one behind the other in the axial direction, preferably pressed together fluidly. In particular, the stator body can be manufactured inexpensively by stamping-packaging.

[0025] Preferably, the electric machine may include a cooling device, wherein the cooling device includes a plurality of cooling channels, each of which extends axially or along an axial direction through the stator body from an inlet (cooling channel inlet) to an outlet (cooling channel outlet), wherein each of the cooling channels is filled with a dielectric material serving as a cooling medium or conducts a dielectric material serving as a cooling medium. Thus, heat generated on the stator during operation of the electric machine can be reliably conducted away.

[0026] The electric machine may optionally include a housing, which may include a first sub-housing and a second sub-housing.

[0027] The first sub-housing can be arranged at the first axial end of the stator and define a first end volume together with the seam tube and the end face of the stator, which first end volume can be configured as an annular space, for example. The first end volume is fluidically connected to the cooling channel (cooling channel inlet) in the stator and is filled with a dielectric material serving as a cooling medium. The winding head / winding extension that may be configured on the conductor element can be arranged in the first end volume. Independently of this, an inlet for supplying / inputting a cooling medium can be configured on the first sub-housing.

[0028] The second sub-housing can be arranged at the second end, in particular at the other axial end of the stator, and together with the seam tube and the end face of the stator, define a second end volume, for example, the second end volume can be configured as an annular space. The second end volume is fluidically connected to the cooling channel (cooling channel outlet) in the stator and is filled with a dielectric material serving as a cooling medium. The winding head, which may be configured on the conductor element, can be arranged in the second end volume. Independently of this, an outlet for conducting the cooling medium can be formed on the second sub-housing.

[0029] The outlet on the second sub-housing can be fluidly connected to the inlet on the first sub-housing. In this fluid connection, a fluid pump for conveying a cooling medium, a cooling medium reservoir and / or one or more heat exchangers for cooling the cooling medium can be incorporated.

[0030] The cooling channels arranged in the stator body can be separate from the stator slots. Thus, the flow resistance can be kept low, since the cooling medium in the cooling channels can "flow freely" without having to flow through or around conductor elements (flow obstacles). The cooling channels can each extend axially or in an axial direction through the stator body. The central longitudinal axis of the cooling channels can each be arranged parallel to the central longitudinal axis of the stator slots.

[0031] Alternatively, for this purpose, the cooling channels can each be arranged in one of the stator slots, so that the conductor element is cooled over the entire axial length of the stator body by the dielectric material acting as a cooling medium, in particular (with respect to the conductor element) the cooling medium flows around it from the "outside". In other words, the cooling channels each coincide with the stator slots (the stator slots are also cooling channels at the same time). As a result, the conductor elements each provided with an insulating layer and arranged in the stator slots can thus be cooled directly by the cooling medium (the cooling medium or the dielectric material is in direct contact with the conductor element). Sufficient cooling is possible even at relatively high current densities. The flow direction of the cooling medium is oriented in particular along or parallel to the central longitudinal axis of the conductor element.

[0032] Thus, a flow of cooling medium, in particular oil, around the conductor elements can occur inside the stator slots and, if a first subshell (first end volume) and / or a second subshell (second end volume) is present, also at the winding heads (the part of the conductor element that protrudes axially from the stator body).

[0033] Preferably, the dielectric material may have a maximum density of 0.75 kg / L at 15°C and / or a maximum density of 6 mm at 40°C. 2 / s and / or a minimum heat capacity of 2.3 kJ / (kg*K) at 80° C. and / or a minimum thermal conductivity of 0.12 W / (m / K) at 80° C. and / or a maximum electrical conductivity of 1000 nS / m at 25° C. Advantageous cooling properties can thereby be achieved.

[0034] Preferably, the electric motor can be configured as a permanent magnet synchronous motor or a separately excited synchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other advantageous configurations of the present invention will become apparent from the following description and the accompanying drawings. The accompanying drawings show:

[0036] Figure 1 A schematic longitudinal section of the electric machine is shown, and

[0037] Figure 2 Show Figure 1 The motor moves along Figure 1 A partial cross-sectional view (section) taken along the cutting axis AA shown in FIG. DETAILED DESCRIPTION

[0038] exist Figure 1 , a longitudinal sectional view of the motor 100 is schematically shown.

[0039] The electric machine 100 comprises a stator 101 with a stator body 102 and a rotor 104 with permanent magnets 104'. The axial direction is marked with reference numeral 105. The stator body 102 surrounds the rotor 104 radially outwardly, wherein the stator body 102 and the rotor 104 are separated from each other by an air gap 106. A slot 107 is arranged in the air gap 106, which separates the space in which the rotor 104 is arranged (rotor space) from the space in which the stator 101 is arranged (stator space). In this example, several magnets 108 are arranged in the rotor 104, which magnets are optionally provided with air pockets 110 (see Figure 2 ).

[0040] The stator body 102 has stator teeth 112 and stator slots 114 that appear alternately in the circumferential direction, and conductor elements 116 are arranged in the stator slots (see Figure 2The structure of the stator body will be explained in further detail below. The conductor elements 116 each include a portion protruding axially from the stator body 102, which forms a winding head 117 (see Figure 1 ).

[0041] The electric machine 100 includes a cooling device having a plurality of cooling channels 115, each of which extends from an inlet 119 through the stator body 102 to an outlet 121. The cooling channels 115 are each filled with a dielectric material 131 (see Figure 2 ). In this example, the cooling channels 115 each coincide with a corresponding stator slot 114. The cooling medium or dielectric material is thus guided directly along the conductor element 116, which in this example is flowed around from the "outside". The dielectric material 131 can have the properties explained above.

[0042] The motor 100 includes a housing 123, which includes a first sub-housing 123' and a second sub-housing 123" (see Figure 1 ). The first sub-housing 123' is arranged at the first axial end of the stator body 102 and defines a first end volume 125' together with the slit tube 107 and the end face 103' of the stator body 102, which in the example is configured as an annular space. The first end volume 125' is fluidically connected to the cooling channel 115 (cooling passage inlet) in the stator body 102 and is filled with a dielectric material 131 serving as a cooling medium. In the first end volume 125', a winding head 117 formed on the conductor element 116 is arranged. An inlet 127 for supplying a cooling medium is configured on the first sub-housing 123'.

[0043] The second sub-housing 123" is arranged at the other axial end of the stator body 102 and, together with the seam tube 107 and the end face 103" of the stator body 102, defines a second end volume 125", which, in this example, is configured as an annular space. The second end volume 125" is fluidly connected to a cooling channel 115 (cooling passage outlet) in the stator body 102 and is filled with a dielectric material 131 acting as a cooling medium. In the second end volume 125", a winding head 117 formed on the conductor element 116 is arranged. An outlet 129 for conducting the cooling medium is configured on the second sub-housing 123". The outlet 129 can be fluidly connected to the inlet 127, as explained above.

[0044] exist Figure 2 In the figure, it is schematically shown that Figure 1A partial sectional view (cross section) or section S of the electric machine 100 is cut through the cutting axis AA in FIG. As explained above, the stator body 102 includes stator teeth 112 and stator slots 114 alternately in the circumferential direction, the stator slots having conductor elements 116 arranged therein. A yoke portion 118 having a radially extending yoke height 120 is formed on the stator body 102 radially outside the stator slots 114 and the stator teeth 112, wherein the stator body 102 has a stator outer radius 122. In this example, a ratio v1 of the yoke height 120 to the stator outer radius 122 is between 0.18 and 0.26 (0.18≤v1≤0.26).

[0045] The stator body 102 has a stator inner radius 124. In this example, the ratio v2 of the stator inner radius 124 to the stator outer radius 122 is between 0.61 and 0.69 (0.61≤v2≤0.69). In this example, the stator outer radius 122 is between 105 mm and 142.5 mm.

[0046] In this example, the motor 100 has a magnetic pole pair number p of p=3 (a total of 6 magnetic poles). In this example, three stator slots 114 are provided on the stator body 102 for each magnetic pole and a conductor element 116 forming a wire bundle or a conductor turn (in Figure 2 , three identically shown stator slots 114 correspond to one strand). In other words, the number of holes (the number of stator slots 114 per pole and per strand) q=3.

[0047] The stator teeth 112 each have a stator tooth width 126. The stator slots 114 each have a stator slot width 128. In this example, a ratio v3 of the stator tooth width 126 to the stator slot width 128 is between 1.05 and 1.50 (1.05≤v3≤1.50).

[0048] At the radially inner ends of the stator teeth 112, respective tooth heads 130 are formed which have an enlarged cross section relative to the stator teeth 112. The tooth heads 130 each extend along a defined tooth head height 132.

[0049] The rotor 104 has a rotor outer radius 134 , wherein the rotor outer radius 134 is smaller than the stator inner radius 124 by a radial height 136 of the air gap 106 (air gap height 136 ). A can 107 is also arranged in the air gap 106 .

[0050] As described above, the conductor element 116 is directly cooled. For this purpose, in the example described, a cooling channel 115 is provided in each stator slot 114 (the stator slot 114 and the cooling channel 115 coincide), wherein the conductor element 116 is cooled over the entire axial length of the stator body 102 by the dielectric material 131 acting as a cooling medium and is circulated around the dielectric material from the outside (see Figure 2 (enlarged portion in ).

[0051] The stator slots 114 are open radially inwardly and are covered or closed by the can 107 . The can 107 rests on the tooth heads 130 of the stator teeth 112 .

[0052] As explained above, the stator body 102 is formed by a lamination stack, wherein several stator laminations are arranged one after another along the axial direction 105, wherein the stator laminations each have a lamination thickness of 0.25 mm or less (see Figure 1 ).

[0053] Figure 1 and 2 The electric machine 100 shown in FIG. 1 can be used to drive a motor vehicle purely electrically. To this end, the electric machine 100 can be powered in motor operation mode by a motor vehicle battery connected to a conductor element 116 in order to generate an electrically generated magnetic field in the stator 101 , which can cooperate with permanent magnets 104 ′ of a rotor 104 , which is in particular dry-running.

Claims

1. An electric machine (100) for a vehicle, the electric machine having a stator (101) including a stator body (102), the stator body (102) including alternating stator teeth (112) and stator slots (114), the stator slots having conductor elements (116) arranged in the stator slots, a yoke portion (118) having a radially extending yoke height (120) formed on the stator body (102) radially outside the stator slots (114), the stator body (102) having a stator outer radius (122), wherein: The ratio (v1) of the yoke height (120) to the stator outer radius (122) is between 0.18 and 0.26, characterized in that a cooling device is provided, the cooling device comprising a plurality of cooling channels (115), each of the cooling channels extending from an inlet (119) along an axial direction (105) through the stator body (102) to an outlet (121), and each of the cooling channels (115) is filled with a dielectric material (131) acting as a cooling medium.

2. The electric machine (100) according to claim 1, characterized in that The stator body (102) has a stator inner radius (124), and a ratio (v2) of the stator inner radius (124) to the stator outer radius (122) is between 0.61 and 0.

69.

3. The electric machine (100) according to claim 1 or 2, characterized in that: The stator outer radius (122) is between 105 mm and 142.5 mm.

4. The electric machine (100) according to claim 1 or 2, characterized in that: Two or three stator slots (114) are arranged on the stator body (102) for each magnetic pole and each strand.

5. The electric machine (100) according to claim 1 or 2, characterized in that: The ratio (v3) of the stator tooth width (126) to the stator slot width (128) is between 0.50 and 0.75 when there are two stator slots (114) per pole and per strand, or the ratio (v3) of the stator tooth width (126) to the stator slot width (128) is between 1.05 and 1.50 when there are three stator slots (114) per pole and per strand.

6. The electric machine (100) according to claim 1 or 2, characterized in that: The electric machine (100) comprises a number p of magnetic pole pairs of p=3.

7. The electric machine (100) according to claim 1 or 2, characterized in that: A tooth head (130) is formed at each radial inner end of the stator teeth (112), and a cross section of the tooth head is enlarged relative to the stator teeth (112).

8. The electric machine (100) according to claim 1 or 2, characterized in that: A slotted tube (107) is arranged adjacent to the stator body in the radial direction inside the stator body (102), and when viewed in the radial direction, the slotted tube (107) covers the stator slot (114).

9. The electric machine (100) according to claim 1 or 2, characterized in that: The stator body (102) is formed of a lamination stack in which a plurality of stator laminations are arranged one after another in an axial direction, the stator laminations each having a lamination thickness of 0.25 mm or less.

10. The electric machine (100) according to claim 1 or 2, characterized in that: The cooling channels (115) are each arranged in one of the stator slots (114) so ​​that the conductor element (116) is cooled over the entire axial length of the stator body (102) with the dielectric material (131) acting as the cooling medium.

11. The electric machine (100) according to claim 10, characterized in that The conductor element (116) is circulated by dielectric material from the outside over the entire axial length of the stator body (102).

12. The electric machine (100) according to claim 1 or 2, characterized in that: The dielectric material (131) has a maximum density of 0.75 kg / L at 15°C and / or a maximum density of 6 mm at 40°C. 2 / s and / or a minimum heat capacity of 2.3 kJ / (kg*K) at 80°C and / or a minimum thermal conductivity of 0.12 W / (m / K) at 80°C and / or a maximum electrical conductivity of 1000 nS / m at 25°C.

13. The electric machine (100) according to claim 1 or 2, characterized in that: The motor (100) is constructed as a permanent magnet synchronous motor or a separately excited synchronous motor.

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