Electric drive system

Abstract

The heat pipes 9a provided here in the grooves 9 of the motor side conduct heat to the end of the output shaft 2 and the heat pipes 10a in the grooves 10 of the housing of the power supply to the opposite end. A flow of heat to axially opposing ends is thus produced that always travels away from the power electronics that are arranged approximately in the center of the system.

Claims

1. In an electric drive system comprising: an electric motor having a stator with a current-feed system and an output shaft defining a rotation axis; a power supply axially adjacent the electric motor and around the rotation axis of the electric motor circumferentially, and a plurality of energy-storage cells in the power supply, the improvement wherein: the power supply is cylindrical and formed by a plurality of axially adjacent disks each in turn subdivided angularly into a plurality of segments each formed with a plurality of axially extending cylindrical seats each holding a respective one of the energy-storage cells, each seat being aligned axially with the seats of adjacent disks; each segment is aligned axially with a respective one of the segments of adjacent disks and forms therewith a respective energy-storage module extending a full axial length of the power supply, independent of the other energy-storage modules, and capable of powering the motor; a control board between opposing axial end faces of the electric motor and of the power supply; and respective power electronics on the control board each connected between a respective one of the energy storage modules and the current-feed system of the electric motor.

2. The electric drive system defined in claim 1, wherein the power supply and the motor each have a housing, the power supply housing being on an axial end of the motor housing opposite the motor output shaft.

3. The electric drive system defined in claim 1, wherein the motor output shaft passes through the power supply and the power supply extends angularly all around the motor output shaft.

4. The electric drive system defined in claim 1, wherein the power-supply has a housing that is cylindrical and whose axis is coaxial with the rotation axis of the motor, the cylindrical power-supply housing not projecting radially outwardly past the motor, radially outwardly directed side surfaces of the motor and the power-supply housing being flush with one another.

5. The electric drive system defined in claim 1, wherein each of the disks has an axial length corresponding to that of the energy-storage cells in the respective cylindrical seats.

6. The electric drive system defined in claim 1, further comprising: at least one interconnection board between two of the disks that are axially adjacent.

7. The electric drive system defined in claim 6, wherein, the at least one interconnection board electrically connects the energy-storage cells in series in groups spaced apart according to the respective segments in the disk angularly.

8. The electric drive system defined in claim 6, further comprising: a further board that extends axially in at least one radially outside region of a cylindrical housing of the power supply in at least one groove, the further board extending substantially over the entire axial length of the cylindrical power-supply housing, the further board being electrically connected to each interconnection board between two disks that are axially adjacent.

9. The electric drive system defined in claim 8, wherein the further board comprises electronics for energy-storage cell management and for checking cell voltages of each segment or in all at least logical/electrical segments of the disks at a common angular position.

10. The electric drive system defined in claim 1, wherein the stator current feed system is formed by a plurality of energizable rods that extend axially through the stator of the electric motor and are connected at one of their ends to a common short-circuit ring and at the other end to the control board.

11. The electric drive system defined in claim 2, wherein the stator current feed system has a plurality of current feed units associated with a number of greater than three phases with the difference in voltage between two phases or a phase and ground being less than or equal to 60 V.

12. The electric drive system defined in claim 1, wherein, in a cylindrical housing of the power supply, each disk is able to be plugged or pushed axially onto guide rods that extend axially from the front face of the electric motor.

13. The electric drive system defined in claim 1, wherein the power supply and the electric motor are thermally insulated from one another by axial spacing and housings of the power supply and of the electric motor are connected only by bars or guide rods.

14. The electric drive system defined in claim 13, wherein the electric motor and the power supply each have a dedicated and independent heat dissipation system in the form of heat pipes that extend axially through the electric motor and/or the power supply for transporting heat to opposite ends.

15. The electric drive system defined in claim 1, wherein at least one groove extends to an inside diameter of a stator in the housing of the motor in which a magnetic field sensor projects from the power electronics of the control board into the groove.

16. The electric drive system defined in claim 1, further comprising, in order to detect a rotation: at least one permanent magnet on the shaft of the electric motor whose magnetic field can be detected by a rotation angle sensor mounted on a front-end control board.

17. The electric drive system defined in claim 1, wherein the control board is formed by into a plurality of segmental portions each aligned with a respective one of the energy-storage modules and each carrying a respective one of the power electronics.

18. The electric drive system defined in claim 1, wherein each segment of each disk is formed with a plurality of the seats.

19. The electric drive system defined in claim 1, wherein the disks are identical.

Description

(1) A preferred embodiment of the invention is described with reference to the figures that follow:

(2) FIG. 1 shows an electric drive system according to the invention with an electric motor 1 and a power supply 6 that is axially adjacent the electric motor.

(3) The power supply 6 is in a cylindrical housing that is here subdivided mechanically axially into a plurality of disks 6a. The disks 6a are pushed onto guide rods 5 that extend axially away from a motor front end.

(4) Each disk can be subdivided logically or with respect to the circuitry embodied therein into disk segments 7 that are here separated by the wide groove 13. Each segment is at an angular position that extends here over an angular range of 90, since a subdivision into four segments angularly has been performed. However, the segmenting is not performed mechanically here, meaning that each disk 6a forms a mechanical unit. In principle, however, it is also possible to also perform the segmenting mechanically.

(5) Here standardized battery cells are used in the cylindrical seats 8 in order to form the power supply of the motor, as shown in FIG. 2. This FIG. 2 also shows stator front-side passages 3 in which a rods (not shown) are disposed in order to energize the stator. Each one or a plurality of the rods can be preferably associated with a phase, particularly with a phase voltage of less than 60 V in each case.

(6) Heat pipes can be in the grooves 9 in order to transfer heat occurring in power electronics of the control board 14 and the heat of the motor 1 to the end of the output shaft that is not shown here. The control board has corresponding terminals 14a for the rods.

(7) The disks 6a can also have grooves 10 on the outside in which heat pipes can be disposed for the purpose of heat transport.

(8) FIG. 1 also shows that interconnection boards 11 (particularly at least one) can be provided between two adjacent disks 6a, particularly between each pair of two adjacent disks 6a in order to perform the interconnection of the battery cells within a disk or the logical/electrical segments 7 thereof and between the adjoining disk 6a or its segments 7. For example, all of the battery cells contained in the disks or their segments can be connected in series in this way. Segmentation can be performed such that each segment also has a dedicated respective board.

(9) On the outer periphery, the interconnection board 11 has a plurality of contacts 12 that can be connected to a board (not shown here) that can be located in the groove 13 that extends axially and is in the outer side of each disk 6a. In performing a segmentation, boards can be provided in the number of segments that are then preferably arranged between two respective segments 7 following one another angularly. Here, the board (not shown) can manage the battery formed by the battery cells.

(10) The control board 14 shown in FIG. 2 comprises power electronics, preferably a set of power electronics 14b arrayed in a segment-like manner for each logical segment for the purpose of controlling the rods 3 of the stator that are disposed in the same angular range of the logical segment in the board 14.

(11) Here, the control board 14 covers a portion of the front end of the motor 3 and substantially all of the front end of the last and first disk 6a.

(12) Together with the control board 14, more particularly segment 14b thereof, the overall arrangement shown here of all of the logical segments 7 of a respective common angular position that are arranged in axial succession with the battery cells and boards contained therein forms a functional unit with which only the electric motor can be operated.

(13) The four functional units in this example form a power supply in terms of the invention that extends angularly over a full 360, particularly forming, in addition, a four-fold redundancy in the process.

(14) The invention is not limited to the four-fold segmentation shown here. There can be more and fewer segments.

(15) FIG. 3 shows an overview of an entire system with the motor 1 whose shaft 2 and power supply 6 that is opposed axially next to the motor 1 in a housing composed of a plurality of disks 6a. These can be secured to the motor by an intermediate plate 6b that encloses the control board(s) of the power electronics.