DRIVE UNIT FOR A CONSTRUCTION AND/OR MATERIAL HANDLING MACHINE

Abstract

The invention relates to a drive unit for a construction and/or material handling machine or lifting equipment such as a crane, comprising a torque density of more than 20 Nm/l at a predetermined output speed, wherein the drive unit comprises a drive motor and a connected transmission, wherein a fast-running electric motor is provided as the drive motor, wherein the motor speed thereof is at least two times said output speed of the drive unit and is reduced by the transmission by a factor of at least 2 to the output speed of the drive unit.

Claims

1. A drive unit for a construction and/or material handling machine or lifting equipment such as a crane, comprising: a torque density of more than 20 Nm/l at a predetermined output speed, wherein the drive unit comprises a drive motor and a connected transmission, wherein the drive motor comprises a fast-running electric motor, wherein the motor speed thereof is at least two times said output speed of the drive unit and is reduced by the transmission by a factor of at least 2 to the output speed of the drive unit.

2. The drive unit of claim 1, wherein the torque density of the drive unit is in the range of 20 to 40 Nm/l or 25 to 30 Nm/l and an engine speed in working operation is more than 4,000 rpm or more than 8,000 rpm or more than 12,000 rpm.

3. The drive unit of claim 1, wherein the electric motor has a speed range of 0 to 5,000 rpm or 0 to 10,000 rpm or 0 to 15,000 rpm.

4. The drive unit of claim 1, wherein the transmission has a transmission ratio of more than 3 in an underdrive ratio.

5. The drive unit of claim 1, wherein the transmission and the electric motor are arranged coaxially to each other, wherein the drive motor comprises a motor shaft, wherein the transmission comprises a transmission output shaft, and wherein the motor shaft is coaxial to a transmission output shaft.

6. The drive unit of claim 5, wherein the transmission is flanged to the electric motor at the end face.

7. The drive unit of claim 1, wherein the drive motor comprises a motor housing, and wherein the transmission comprises a transmission housing, and wherein the motor housing and the transmission housing have approximately the same diameter.

8. The drive unit of claim 7, wherein the motor housing is separate from the transmission housing and said motor and transmission housings are rigidly, releasably connectable to each other.

9. The drive unit of claim 7, wherein the transmission and the electric motor are in a common housing and the motor housing and transmission housing are integrally connected to one another in one homogeneous piece.

10. The drive unit of claim 1, wherein the drive unit has a length/diameter ratio (L/d) in the range of 2 to 4.

11. The drive unit according to claim 1, wherein the drive motor and the transmission have a common coolant circuit.

12. The drive unit of claim 11, wherein the transmission and the electric motor are liquid-cooled.

13. The drive unit of claim 1, wherein the coolant circuit has an inlet at a transmission-side end portion of the electric motor and a coolant outlet at an end portion of the electric motor facing away from the transmission.

14. The drive unit of claim 1, wherein the transmission comprises a coaxial transmission stage.

15. The drive unit of claim 14, further comprising an upright planet carrier fixedly connected to a motor and/or transmission housing, and wherein the upright carrier carries a pivot bearing for a transmission input shaft and/or a motor shaft.

16. A drive unit of claim 1, wherein the drive unit has a collar-shaped mounting flange for attachment to a machine unit to be driven, wherein the mounting flange is at a frontal transmission housing end portion.

17. A method for using the drive unit of claim 1 for replacement with a hydraulic drive for driving a machine unit of a construction and/or material handling machine or lifting equipment.

18. A drive set comprising the drive unit of claim 1 and a hydraulic drive, wherein the drive unit and the hydraulic drive have corresponding connection flanges and have torque densities that differ from each other by less than 50%.

19. A drive set comprising the drive unit of claim 1 and a hydraulic drive, wherein the drive unit and the hydraulic drive have corresponding connection flanges and have torque densities that differ from each other by less than 30%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention is explained in more detail below on the basis of a preferred exemplary embodiment and the corresponding drawings. The drawings show:

[0028] FIG. 1: shows a perspective view of a drive unit with a high-speed electric motor and a speed-reducing transmission according to an advantageous embodiment of the invention;

[0029] FIG. 2: shows a side view of the drive unit of FIG. 1, wherein the bearing of the output shaft is shown partially cut; and

[0030] FIG. 3: shows a longitudinal portion through the drive unit from the previous figures, showing the frontal, coaxial connection of the transmission to the electric motor.

DETAILED DESCRIPTION

[0031] As shown in the figures, the drive unit 1 comprises a drive motor 2, which is configured as a high-speed electric motor, and a speed-reducing gear 3 connected thereto, which reduces the motor speed of the electric motor to the output speed of the drive unit 1.

[0032] The drive motor 2 and the transmission 3 can advantageously be arranged coaxially to each other, whereby in particular the transmission output shaft 4 can be arranged coaxially to the motor shaft 5, cf. FIG. 3.

[0033] The transmission 3 may be housed in a—roughly speaking—cylindrical transmission housing 6, which may have a collar-shaped mounting flange 7 by means of which the drive unit 1 can be mounted on the installation environment of a machine unit to be driven.

[0034] The drive motor 2 may comprise a motor housing separate from the transmission housing 6, wherein the transmission housing 6 may be flanged to the motor housing 8 at the end face. As an alternative to separate motor and transmission housings, however, it would also be possible to accommodate the electric motor and the transmission in a common housing and/or to integrally form said transmission and motor housings 6 and 8.

[0035] Advantageously, the motor housing 8 and the transmission housing 6 can have at least approximately the same diameter, so that the drive unit 1 as a whole forms a slim, elongated, approximately cylindrical unit.

[0036] As FIG. 1 and FIG. 3 show, on one end face of the drive unit 1 the transmission output shaft 4 can project a little way out of the housing of the drive unit 1 in the manner of a stub shaft. Electrical connections for supplying and/or controlling the electric motor 2 can be provided on the opposite end face of the drive unit 1, see FIG. 3.

[0037] The electric motor can be of various designs, with synchronous and asynchronous motors basically being considered. For example, the electric motor can be a synchronous motor with permanent magnet.

[0038] The electric motor 2 is configured for a high speed range as intended, wherein a speed range of 4,000 to 20,000 rpm or 5,000 to 15,000 rpm or 8,000 to 12,000 rpm intended for working operation can be provided. The entire speed range can, of course, start at 0 and in this respect range from 0 to 20,000 rpm or 0 to 15,000 rpm in order to be able to start from standstill in working mode.

[0039] Advantageously, the electric motor has a maximum speed that is at least 10,000 rpm. Advantageously, the motor can be operated at speeds in the range from 8,000 to 16,000 rpm or 10,000 to 14,000 rpm.

[0040] The transmission 3 connected to the electric motor 2 advantageously has a transmission ratio of more than 2 or even more than 3, wherein the transmission ratio can advantageously be 4 to 5. The motor speed of the electric motor 2 is thus reduced by at least a factor of 2 or a factor of 3, in particular by a factor of 4 to 5, so that the output speed can be in the range of ½ to ⅕ of the motor speed. For example, if the electric motor runs at the speed of 14,000 rpm, the output speed of the drive unit 1, that is, the speed of the transmission output shaft 4 is approximately 3,000 If the electric motor 2 can be run at a speed range of zero to 14,000, the output speed of the drive unit 1 is zero to 3,000.

[0041] In order to be able to achieve said transmission ratio with a slim design, the transmission 3 can comprise at least one planetary gear stage 9. As FIG. 3 shows, such a planetary gear stage 9 may comprise an upright planet carrier 10, which may be rigidly connected to the motor housing 8 and/or the transmission housing 6. Advantageously, said planet carrier 10 can carry or support a pivot bearing 11 on which the motor shaft 5 and/or a transmission input shaft 12 is supported.

[0042] As FIG. 3 shows, the sun gear 13 may be rotationally fixed to the transmission input shaft 12 and in rolling engagement with the planets rotatably mounted on the planet carrier 10. A ring gear 14, which is in rolling engagement with the planet gears, can drive the transmission output shaft 4, in particular be connected to it in a rotationally fixed manner.

[0043] The drive unit 1 comprising the electric motor 2 and the transmission 3 may have a torque density of more than 20 Nm/l, for example a torque density of 20 to 40 or 25 to 30 Nm/l.

[0044] The drive unit 1 can provide a torque of, for example, more than 500 Nm or more than 1,000 Nm, for example in a range of 500 to 2,000 Nm or 1,000 to 1,500 Nm. Advantageously, however, the drive unit 1 can also start up very gently and also provide small torques starting at 0, which can then be raised to the level mentioned in the desired manner.