Back to results
US 2004/0104624 A1Published application
Linear motor drive unit for a machine
OwnerKarl Hehlinventor
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
OwnerKarl Hehlinventor
Estimating the term…
The invention relates to a drive unit for a machine, especially an injection press. Said drive unit comprises several linear motors (L1, L2) parallel to each other in a common advance direction (a-a), said motors having equally acting members which are mutually connected for common motion. Said linear motors (L1, L2) comprise magnetic elements (23, 24) in the advance direction as well as coil elements (26, 27) co-operating with the magnetic elements. According to the invention, force determination means (40) for determining the path-dependent force of the linear motors (L1, L2) are installed at least during assembly or initial operation and a controller (41) is used during operation for setting the power delivered to the linear motors (L1, L2) by the power part to a desired characteristic on the basis of the force depending from the linear motor position determined by the force determination means, whereby a smooth force characteristic can be obtained.
Drive unit (D) for a machine, more especially an injection molding machine for processing plastics materials and other plasticizable substances including a plurality of linear motors (L1, L2), which are disposed parallel to each other in a common direction of feed (a-a), the parts of the linear motors (L1, L2) with the same action being interconnected for common displacement, wherein the linear motors (L1, L2) include magnetic elements (23, 24) in the direction of feed and coil elements (26, 27) communicating therewith, wherein at least one power unit (42, 43) is associated with the linear motors, characterized in that force determining means (40) are provided for determining the path-dependent force of the linear motors (L1, L2) at least during assembly or respectively commissioning and in that, in the operating state, a controller (41) regulates, to a required characteristic, the power which is supplied to the linear motors (L1, L2) by the power unit in dependence on the force, which is dependent on the path position of the linear motors and is determined by the force determining means.
Drive unit according to one of the preceding claims, characterized in that the linear motors (L1, L2) are disposed so as to be symmetrical relative to a common effective axis, which lies parallel to the direction of feed (a-a).
Drive unit according to one of the preceding claims, characterised in that the linear motors (L1, L2) are disposed coaxially one to the other.
Drive unit according to one of the preceding claims, characterized in that the cylindrical linear motors (L1, L2) are nested into one another.
Drive unit according to one of the preceding claims, characterized in that a hollow cylindrical rotor in the form of a magnet carrier (22) includes magnetic elements (23, 24) disposed on its two lateral surfaces, which magnetic elements (23, 24) interact with coil elements (26, 27) to form the drive unit (D) which includes the two linear motors (L1, L2), said coil elements (26, 27) being disposed on lateral surfaces of coil rings (20, 21) which are configured as stators.
Drive unit according to one of the preceding claims, characterized in that the magnetic elements (24) and/or coil elements (26) of one linear motor (L2) situated on the inside are offset axially relative to the magnetic elements (23) and/or coil elements (27) of one linear motor (L1) situated on the outside.
Drive unit according to one of the preceding claims, characterized in that the displacement is v=a/(p×2),
Drive unit according to one of the preceding claims, characterized in that the magnetic elements (23, 24) at least of one linear motor (L1, L2) are offset in a stepped manner along its circumference.
Drive unit according to one of the preceding claims, characterized in that the length b of the magnetic elements (23, 24) of the individual linear motors (L1, L2) and the length a of the set of coil elements (26, 27) of the individual linear motors, which length is tuned to the length of said magnetic elements, is independent of each other.
Drive unit according to one of the preceding claims, characterized in that the coil elements (26, 27) are disposed inclinedly relative to the feed direction in the form of an ellipsoid on the lateral surface of the linear motors (L1, L2).
Dependencies are inferred from the claim text.