Drive and method for operating a drive

Patent metadata

Field	Value
Publication number	US-10626973-B2
Application number	US-201615094106-A
Country	US
Kind code	B2
Filing date	Apr 8, 2016
Priority date	Apr 10, 2015
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

Drive having a commutated electric motor (10), having a coaxial gearing (20) which is connected to the electric motor (10) and which comprises: an internal gear with an internal toothing (5); a tooth carrier (11) in which there are received a multiplicity of teeth (7) for engagement with the internal toothing, wherein the teeth are mounted so as to be radially displaceable relative to the tooth carrier (11) in the longitudinal direction of the teeth (7); a drive-input element with a profiling (22) for the radial drive of the radially displaceably mounted teeth (7), and having a gearing rotary encoder (30) which is connected to the drive output (25) of the gearing (20), wherein the gearing rotary encoder (30) is arranged and designed to detect a drive-output angular position and to output said drive-output angular position as a drive-output angle signal (δ).

First claim

The invention claimed is:

1. A drive, comprising:
a commutated electric motor ( 10 ) having a drive-output side (B), a non-drive-output side (A) and a hollow shaft ( 15 ) at the drive-output side (B), the hollow shaft ( 15 ) being driven by the motor ( 10 );
a coaxial gearing ( 20 ) which is driven by the hollow shaft ( 15 ), the coaxial gearing ( 20 ) comprising:
an internal gear ( 3 ) with an internal toothing ( 5 );
a tooth carrier ( 11 );
a multiplicity of teeth ( 7 ) received within the tooth carrier ( 11 ) and radially displaceable relative to the tooth carrier ( 11 ) in a longitudinal direction of the teeth ( 7 ) for engaging the internal toothing ( 5 ) of the internal gear ( 3 ); and
a drive-input element having a profiling ( 22 ) for radial drive of the multiplicity of teeth ( 7 );

a drive output shaft ( 25 ) which is driven by the coaxial gearing ( 20 ), the drive output shaft ( 25 ) passing through the hollow shaft ( 15 ) and having a drive-output end ( 26 ) for driving a load ( 70 ) and a non-drive-output end ( 27 ) opposite from the drive-output end ( 26 ); and
a gearing rotary encoder ( 30 ) which is connected to the drive output shaft ( 25 ) of the gearing on the non-drive output end ( 27 ), wherein the gearing rotary encoder ( 30 ) is arranged and configured to detect a drive-output angular position of the drive output shaft ( 25 ) of the gearing and to output the drive-output angular position as a drive-output angle signal (δ), wherein the gearing rotary encoder ( 30 ), the commutated electric motor ( 10 ), the coaxial gearing ( 20 ), and the load ( 70 ) are positioned along the drive output shaft ( 25 ), in that order, from the non-drive-output end ( 27 ) to the drive-output end ( 26 ).

2. The drive according to claim 1 , wherein the gearing ( 20 ) and the electric motor ( 10 ) are connected to one another by way of the hollow shaft ( 15 ) for the transmission of a drive torque of the electric motor ( 10 ).

3. The drive according to claim 1 , wherein the teeth ( 7 ) of the gearing ( 20 ) are guided in each case at least one of radially or linearly in the tooth carrier ( 11 ).

4. The drive according to claim 1 , wherein the drive-input element comprises a cam disk ( 21 ).

5. The drive according to claim 1 , further comprising:
a commutation device ( 40 ) for the electric motor ( 10 ), wherein the commutation device ( 40 ) is configured to determine, from the drive-output angle signal (δ), a calculated rotor angular position of the electric motor ( 10 ) and to generate a commutation signal (k), containing a setpoint torque signal, for the electric motor ( 10 ) using the calculated rotor angular position.

6. The drive according to claim 5 , wherein the commutation device ( 40 ) is further configured to:
determine an estimated angular position deviation value between the calculated rotor angular position and an estimated rotor angular position from the setpoint torque signal and from a rigidity of the gearing ( 20 );
determine a corrective signal for the rotor angular position from the deviation value; and
superpose the corrective signal on the commutation signal.

7. The drive according to claim 6 , wherein the commutation device ( 40 ) is further configured to:
estimate an estimated rotor angular position of the electric motor ( 10 ) from a measured back-EMF;
determine an angular position deviation value between the calculated rotor angular position and the estimated rotor angular position; and
determine a drive output torque from the rotational angle position deviation value and from the rigidity of the gearing.

8. The drive according to claim 1 , wherein a rotational degree of freedom of the teeth ( 7 ) relative to the tooth carrier ( 11 ) about the longitudinal axis of the gearing ( 1 ) is blocked.

9. The drive according to claim 1 , further comprising:
a commutation device ( 40 ) for the electric motor ( 10 ), wherein the commutation device ( 40 ) is configured to determine, from the drive-output angle signal (δ) and from a transmission ratio of the coaxial gearing ( 20 ), a calculated rotor angular position of the electric motor ( 10 ) and to generate a commutation signal (k) for the electric motor ( 10 ) using the calculated rotor angular position.

10. The drive according to claim 1 , wherein the commutated electric motor ( 10 ) is free of a motor rotary encoder.

11. A method for operating a drive comprising:
a commutated electric motor ( 10 ) having a drive-output side (B), a non-drive-output side (A) and a hollow shaft ( 15 ) at the drive-output side (B), the hollow shaft ( 15 ) being driven by the motor ( 10 );
a coaxial gearing ( 20 ) which is driven by the hollow shaft ( 15 ), the coaxial gearing comprising:
an internal gear with an internal toothing ( 5 );
a tooth carrier ( 11 );
a multiplicity of teeth ( 7 ) received within the tooth carrier ( 11 ) and radially displaceable relative to the tooth carrier ( 11 ) in a longitudinal direction of the teeth ( 7 ) for engaging the internal toothing ( 5 ) of the internal gear ( 3 ); and
a drive-input element having a profiling ( 22 ) for radial drive of the multiplicity of teeth ( 7 );

a drive output shaft ( 25 ) which is driven by the coaxial gearing ( 20 ), the drive output shaft ( 25 ) passing through the hollow shaft ( 15 ) and having a drive-output end ( 26 ) for driving a load ( 70 ) and a non-drive-output end ( 27 ) opposite from the drive-output end ( 26 ); and
a gearing rotary encoder ( 30 ) which is connected to the drive output shaft ( 25 ) of the gearing on the non-drive output end ( 27 ), wherein the gearing rotary encoder ( 30 ) is arranged and configured to detect a drive-output angular position of the drive output shaft of the gearing and to output the drive-output angular position as a drive-output angle signal (δ), wherein the gearing rotary encoder ( 30 ), the commutated electric motor ( 10 ), the coaxial gearing ( 20 ), and the load ( 70 ) are positioned along the drive output shaft ( 25 ), in that order, from the non-drive-output end ( 27 ) to the drive-output end ( 26 ), the method comprising the steps of:
detecting the drive-output angular position on the drive-output side (B) of the coaxial gearing ( 20 );
calculating a calculated rotor angular position of the electric motor ( 10 ) from the detected drive-output angular position and from a transmission ratio of the coaxial gearing ( 20 ); and
providing a commutation signal (k) for the electric motor ( 10 ) using the calculated rotor angular position.

12. The method according to claim 11 , wherein the commutation signal (k) contains a setpoint torque signal, and further comprising the steps:
determining an estimated angular position deviation value between the calculated rotor angular position and an estimated rotor angular position from the setpoint torque signal and from the rigidity of the gearing ( 20 );
determining a corrective signal for the rotor angular position from the deviation value; and
superposing the corrective signal on the commutation signal.

13. The method according to claim 12 , further comprising the steps:
measuring a back-EMF at an exciter coil of the electric motor ( 10 );
estimating an estimated rotor angular position of the electric motor ( 10 ) from the back-EMF;
determining an angular position deviation value between the calculated rotor angular position and the estimated rotor angular position; and
determining a drive output torque from the rotational angle position deviation value and from the rigidity of the gearing.

14. The method according to claim 13 , wherein the calculated rotor angular position and/or the estimate

Assignees

• Wittenstein Ag
• Wittenstein Se

Inventors

• Burger Tobias
• Hoffmann Rolf
• Isabey Philippe

Classifications

• H02P3/00

  Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters (stopping of synchronous motors with electronic commutators H02P6/24; stopping dynamo-electric motors rotating step by step H02P8/24; vector control H02P21/00) · CPC title

• F16H2049/003

  Features of the flexsplines therefor · CPC title

• H02P1/00

  Arrangements for starting electric motors or dynamo-electric converters (starting of synchronous motors with electronic commutators H02P6/20, H02P6/22; starting dynamo-electric motors rotating step by step H02P8/04; vector control H02P21/00) · CPC title

• F16H49/001 Primary

  Wave gearings, e.g. harmonic drive transmissions · CPC title

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title