Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-11-12
2001-12-25
Tamai, Karl (Department: 2834)
Metal working
Method of mechanical manufacture
Electrical device making
C310S235000, C310S236000
Reexamination Certificate
active
06332263
ABSTRACT:
PRIOR ART
The invention is based on a rotor for a commutator machine.
With a known rotor of this type (WO 90/04864), the connection lugs on the collector or commutator lamellas are embodied as hooks that are bent back at an acute angle to the lamellas each of whose hook bases respectively has a winding wire running around it. The electrical and mechanical connection between the winding wires and the connection lugs takes place by means of bending the hooks over and by means of ultrasonically welding the hook ends to the collector lamellas, for which a sonotrode of an ultrasonic torsion welding device is simultaneously used as a bending tool.
With a known ultrasonic torsion welding device for fastening the winding wires to the connection lugs of commutator lamellas (DE 89 02 562 U1) with a sonotrode which produces high-frequency mechanical vibrations and presses with an axial force against the wire windings of the winding wires disposed around the connection lugs, and with an anvil that supports the connection lugs during the welding process, the anvil and the free end of each connection lug are provided with support faces that absorb the sonotrode pressure and the sonotrode vibrations lateral to the pressing direction, which support faces can be placed against each other before the beginning of the welding process by means of a relative movement of the anvil and the connection lugs. The support face, which is embodied on the anvil that can be moved radial to the sonotrode axis, thereby engages behind the connection lugs of the commutator lamellas on their back side oriented away from the sonotrode and consequently absorbs the axial pressure of the sonotrode to a large extent. The sonotrode has a flat, annular welding surface, which is pressed onto the winding wires.
In both cases, the use of the ultrasonic torsion welding process requires a particular geometric embodiment of the connection lugs that contain the winding wires and this in turn requires a particular winding technique of the rotor winding. Furthermore, a certain minimum distance between the rotor body and the commutator is required in order to be able to guide the support faces of the anvil radially behind the connection lugs.
ADVANTAGES OF THE INVENTION
The rotor according to the invention, has the advantage that the ultrasonic torsion welding, with its technical manufacturing advantages, can also be used with conventional rotors, in fact with no changes or with only slight changes to the rotor geometry.
Through the support according to the invention of the complete commutator against the rotor body the commutator is secured against moving on the rotor shaft during the welding so that a separate anvil is not required to absorb the high axial forces of the sonotrode. For the possible, but not absolutely required absorption of the remaining slight axial forces acting on the connection lugs, it is sufficient to supply corresponding low-volume support faces of the anvil to the rotor shaft, for the supply of which, even in conventional rotors, there is still sufficient space between the winding heads of the rotor winding on the rotor body and the connection lugs on the commutator or by means of recesses in the rotor body.
Alternatively and independently of the geometry of the connection lugs, according to an advantageous embodiment of the invention, the connection lugs can also be supported against the insulation material body, at least in the region in which they bend away from the commutator lamellas.
By means of the alternative or additional bending, of the connection lugs by approximately 90° outward and the hook-like bending of the end of the connection lugs into a securing hook to prevent the connection wires wound around the connection lugs from slipping out during the welding process, an automatically executable hooking technique can be produced, which is quite similar to the technique in existing products. According to an advantageous embodiment of the invention, an additional wire securing for the winding process is produced by means of the T-shaped embodiment of the free end of the connection lugs.
According to an alternative or improved embodiment of the invention if wire catches are provided on the inner surfaces of the connection lugs that are bent outward by approximately 135°, which inner surfaces are oriented toward the commutator lamellas, then in conventional rotors, the previous hooking technique can be maintained, wherein the wire catches prevent the connection wires from slipping into the bottom of the bend or hook during the welding process.
A device for ultrasonic torsion welding, which takes into account the embodiment of the rotor has been set forth herein.
If the intent is to avoid changes to the connection lugs in order to stop the connection wire windings from slipping out during the welding process, then according to an alternative embodiment of the device, the wire catches can be moved from the connection lugs to the support faces of an anvil that supports the connection lugs during the welding process. To this end, according to the device for ultrasonic torsion welding, the support faces of the anvil that extend at a 45° angle to the sonotrode axis are provided with wire clamping segments and after the placement of the support faces against the outer faces of the connection lugs oriented away from the commutator lamellas, these wire clamping segments protrude beyond the inner surface of the connection lugs on at least one side of each connection lug in the vicinity of the bottom of the bend or hook enclosed with the commutator lamellas.
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Abstract of Japanese Patent 61-085,037, Apr. 1986.
Kobschaetzky Hans
Schmidt Ralf
Greigg Ronald E.
Robert & Bosch GmbH
Tamai Karl
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