Abstract
An unenclosed electric traction machine has a stator built up from a stator laminated core, and a rotor shaft with a rotor, mounted on the latter, built up from a rotor laminated core, wherein the stator laminated core is arranged between two outer pressing plates, and at least one bearing shield, which in each case has a bearing for the rotor shaft. Along a section of the periphery of the stator laminated core, and spaced apart from the stator laminated core, at least one cover, designed as a tension bar between the pressing plates, is arranged between the pressing plates so as to form at least one cooling box, with a base on the surface of the stator laminated core, wherein the at least one intermediate space between the base and the at least one cover of the cooling box is designed for the routing of a cooling fluid.
Claims
1. An unenclosed electric traction machine (1), with a stator (2) built up from a stator laminated core (3), and a rotor shaft (4) with a rotor (5), mounted on the latter, built up from a rotor laminated core (6), wherein the stator laminated core (3) is arranged between two outer pressing plates (7, 8), and at least one bearing shield (29, 30), which in each case has a bearing (24) for the rotor shaft (4), wherein, along a section of the periphery of the stator laminated core (3), and spaced apart from the stator laminated core (3), at least one cover (9), designed as a tension bar between the pressing plates (7, 8), is arranged between the pressing plates (7, 8) so as to form at least one cooling box (10), with a base (17) on the surface of the stator laminated core (3), wherein the at least one intermediate space (11) between the base (17) and the at least one cover (9) of the cooling box (10) is designed for the routing of a cooling fluid (K).
2. The unenclosed electric traction machine (1) according to claim 1, wherein two cooling boxes (10) are arranged in each case over a circumferential angle (α) of 60° to 135°, preferably of essentially 90°.
3. The unenclosed electric traction machine (1) according to claim 1, wherein webs (12) are arranged in the intermediate space (11) of each cooling box (10), and at least one inlet (13) and at least one outlet (14) for the cooling fluid (K) are arranged in at least one pressing plate (7, 8), for the meandering routing of the cooling fluid (K) between the webs (12) in the intermediate space (11).
4. The unenclosed electric traction machine (1) according to claim 1, wherein openings (15) for the cooling fluid (K) are arranged in a pressing plate (7, 8).
5. The unenclosed electric traction machine (1) according to claim 4, wherein a deflection device (16) for the cooling fluid (K) is arranged outside the pressing plate (7, 8) with the openings (15) for the cooling fluid (K).
6. The unenclosed electric traction machine (1) according to claim 1, wherein the base (17) is connected, preferably welded, to the stator laminated core (3), at least at some places.
7. The unenclosed electric traction machine (1) according to claim 1, wherein the base (17) is connected by means of a form fit to the stator laminated core (3), at least at some places.
8. The unenclosed electric traction machine (1) according to claim 1, wherein the base (17) has openings (18), preferably in the form of elongated holes (19).
9. The unenclosed electric traction machine (1) according to claim 1, wherein a heat conducting membrane (20) is arranged between the base (17) and the stator laminated core (3).
10. The unenclosed electric traction machine (1) according to claim 1, wherein the pressing plates (7, 8) are designed to be essentially rectangular.
11. The unenclosed electric traction machine (1) according to claim 1, wherein the cooling fluid (K) takes the form of cooling water.
12. The unenclosed electric traction machine (1) according to claim 1, wherein a coupling (21) for connection to a transmission (22), preferably a curved-tooth coupling (23), is arranged on the drive side (A) of the rotor shaft (4).
13. The unenclosed electric traction machine (1) according to claim 1, wherein the at least one bearing (24) in the at least one bearing shield (29, 30) takes the form of an angular contact ball bearing (25).
14. The unenclosed electric traction machine (1) according to claim 1, wherein at least one heat pipe (26), with a free end, or connected to a heat sink (27), is arranged in the rotor laminated core (6), for purposes of cooling the rotor (3).
Description
[0026] The present invention is explained in more detail with reference to the accompanying drawings. Here:
[0027] FIG. 1 shows in perspective a schematic illustration of an unenclosed electric traction machine in accordance with the invention;
[0028] FIG. 2 shows a further view in perspective of an unenclosed electric traction machine in accordance with the invention;
[0029] FIG. 3 shows a partially sectioned side view of the unenclosed electric traction machine shown in FIG. 2;
[0030] FIG. 4 shows a section through the unenclosed electric traction machine shown in FIG. 3, along the section line IV-IV;
[0031] FIG. 5 shows a section through the unenclosed electric traction machine shown in FIG. 4, along the section line V-V;
[0032] FIGS. 6a to 6c show in plan view and side view various shapes of bases for purposes of forming the cooling boxes; and
[0033] FIG. 7 shows in perspective a schematic illustration of an unenclosed electric traction machine connected to a transmission.
[0034] FIG. 1 shows in perspective a schematic illustration of an unenclosed electric traction machine 1 in accordance with the invention. The electric traction machine 1, designed as an internal rotor motor, consists of a stator 2, which is built up from an appropriate stator laminated core 3, and a moving part, the rotor 5, which is built up from a rotor shaft 4, and a rotor laminated core 6, mounted on the latter. The stator laminated core 3 of the stator 2 is arranged between two outer pressing plates 7 and 8. Outside each of the pressing plates 7 and 8 is a bearing shield 29 and 30, having appropriate bearings 24 (indicated by dashed lines) for the support of the rotor shaft 4. The electric traction machine 1 may also contain only one bearing 24 in one bearing shield 29 or 30, and the second bearing for the rotor shaft 4 may be integrated into a coupling 21 or a transmission 22 (see FIG. 7).
[0035] In accordance with the invention, along a section of the periphery of the stator laminated core 3, and spaced apart from the stator laminated core 3 between the pressing plates 7 and 8, at least one cover 9, designed as a tension bar between the pressing plates 7 and 8, is arranged so as to form a cooling box 10. In the example of embodiment illustrated, two cooling boxes 10 are formed by two covers 9 designed as tension bars. A cooling fluid K can be routed within the intermediate space 11 between the stator laminated core 3 and the respective cover 9 of each cooling box 10, so as to be able to dissipate the heat generated in the electric traction machine 1.
[0036] FIG. 2 shows in perspective a further schematic illustration of an unenclosed electric traction machine 1 in accordance with the invention. In accordance with the invention, the result is an electric traction machine 1 that has a height h that is reduced in comparison with the width b. The cooling fluid K can be conveyed into the cooling box 10, and out of the cooling box 10, by way of appropriate inlets 13 and outlets 14 in the pressing plate 7 and/or 8. For example, an inlet 13 for the cooling fluid K is located in each cooling box 10, and an outlet 14 for the cooling fluid K is located in the pressing plate 7 or 8. Openings 15 for the cooling fluid K can be arranged in the opposite pressing plate 8 or 7, where the cooling fluid K is routed out of the cooling box 10 and is led back into the latter. Appropriate deflection devices 16 serve to provide the redirection of the cooling fluid K outside the pressing plate 8 or 7.
[0037] FIG. 3 shows a partially sectioned illustration of the unenclosed electric traction machine 1 shown in FIG. 2. Here is illustrated the rotor 5 of the electric traction machine 1, consisting of a rotor shaft 4 and a rotor laminated core 6. The cooling fluid K passes from the cooling box 10, by way of the opening 15, into the deflection device 16, where the cooling fluid K is routed back into the cooling box 10 by way of a further opening 15 (see also FIG. 5). A heat pipe 26 may be arranged in the rotor shaft 4, the free end of which may be connected to a heat sink 27. The length l.sub.w of the rotor shaft 4 can be between 100 mm and 980 mm. The length l of the entire electric machine can be, for example, between 110 mm and 1,000 mm. A rotary encoder (not shown) may be arranged on the non-drive side NA of the electric traction machine 1; this may be used to control the number of rotations. A toothed disc, which generates the signals for such an encoder, could be used as a heat sink 27 for the heat pipe 26.
[0038] FIG. 4 shows the section view through the unenclosed electric traction machine 1 shown in FIG. 3, along the section line IV-IV. This section view shows a cooling box 10 with the inlet 13, the outlet 14 and a web 12. Heat from the stator laminated core 3 and the base 17 is transferred to the cooling fluid K in the cooling box by way of a heat conducting membrane 20, and dissipated accordingly. The cover 9 for purposes of forming the cooling box 10 is at the same time designed as a tension bar between the pressing plates 7, 8 of the electric traction machine 1. In the example of embodiment illustrated, the cooling box 10 extends over a circumferential angle a of somewhat less than 90°. The distance a between the cover 9 and the stator laminated core 3 is preferably 6 mm to 60 mm. The diameter d of the rotor shaft 4 is, for example, 20 mm to 100 mm.
[0039] FIG. 5 shows the section view through the unenclosed electric traction machine 1 shown in FIG. 4, along the section line V-V. The cooling fluid K enters a sub-compartment of the cooling box 10 by way of the inlet 13, which sub-compartment is separated from the other sub-compartment by the web 12. By way of an opening 15 in the pressing plate 8, the cooling fluid K also enters the region outside the cooling box 10, so as to be able also to cool the winding heads there, for example. By way of a deflection device 16, which is designed in the form of a cap-like construction arranged on the pressing plate 8 and welded to the latter, the cooling fluid K is guided by way of a further opening 15 in the pressing plate 8 into the lower part of the cooling box 10, and is led out of the electric traction machine 1 by way of the outlet 14 in the pressing plate 7.
[0040] FIGS. 6a to 6c show in plan view and side view various shapes of bases 17 for purposes of forming the cooling boxes 10. FIGS. 6a, 6b and 6c show various forms of embodiment of a base 17, which is arranged on the upper side of the stator laminated core 3, and is connected to it, for example by means of material bonding, in particular by welding. In FIG. 6a, the base 17 has a solid surface design. In FIG. 6b, openings 18 of any shape are provided in the base 17. In the variant in FIG. 6c, openings 18 in the form of elongated holes 19 are located in the base 17. When connecting the base 17 to the surface of the stator laminated core 3, a material bond is created, preferably on the periphery of the base and on the periphery of the openings 18, or elongated holes 19. Instead of a material bond, the base 17 can also be at least partially connected by means of a form fit to the stator laminated core 3.
[0041] Finally, FIG. 7 shows in perspective a schematic illustration of an unenclosed electric traction machine 1 connected to a transmission 22. A coupling 21 can be provided on the drive side A of the rotor shaft 4, for connection to a transmission 22. The coupling 21 can, for example, be implemented in the form of a curved-tooth coupling 23.
