An EC motor for an electric hand tool having a stator in which a rotor is rotatably mounted, which comprises a rotor lamination stack, which has a passage opening and is formed of individual laminations, and a rotor shaft which is cast in the passage opening of the rotor lamination stack by means of a casting compound, and having a plurality of permanent magnets, which are received in the pockets formed in the rotor lamination stack. An annular channel, which is connected to the pockets in a fluid-conducting manner via radial channels, each of which is formed of a plurality of channel sections formed in adjacent laminations of the rotor lamination stack, is formed between the rotor shaft and the wall of the passage opening for supplying the casting compound from the annular channel to the pockets. A method is also provided for producing a rotor for an EC motor.

A speed reducer comprises a transmission shaft, an eccentric wheel, a first wheel assembly, a rotating wheel and a second wheel assembly. The first wheel assembly comprises a first wheel disc and at least one first roller. The at least one first roller is disposed on the inner wall of first wheel disc. The rotating wheel comprises a main body comprising an outer ring structure and a concave structure. The outer ring structure comprises at least one first tooth. The at least one first tooth is in contact with the corresponding first roller. At least one second roller is disposed within the concave structure. The second wheel assembly comprises a second wheel disc and at least one second tooth. The at least one second tooth is disposed on an outer periphery of the second wheel assembly. The at least one second tooth is in contact with the corresponding second roller.

A speed reducing device includes a motor and a speed reducing mechanism. The speed reducing mechanism includes at least one roller assembly, a cycloid disc, at least one fixing disc and a positioning assembly. The roller assembly is disposed within a rotor portion of the motor. While the roller assembly is rotated with the rotor portion, the roller assembly is eccentrically revolved. The roller assembly includes a wheel disc and at least one roller. The cycloid disc includes a main body and at least one cycloid tooth structure. The cycloid tooth structure is protruded from an outer periphery of the main body and in contact with the corresponding roller. While the roller assembly is eccentrically revolved, the at least one cycloid tooth structure is pushed against the corresponding roller, so that the cycloid disc is correspondingly rotated.

In the case of a laminated rotor core 10, insertion of permanent magnets 14 and filling of resin 15 into each of magnet insertion holes 13 are performed in order to cancel out a problem of an imbalanced weight estimated from a deviation of lamination thickness in a circumferential direction of a laminated core body 12, and a manufacturing method includes a step of measuring a deviation of lamination thickness in which an imbalanced weight is estimated by measuring the deviation of lamination thickness in the circumferential direction of the laminated core body 12, and a step of balance adjustment in which the insertion of the permanent magnets 14 into each of the magnet insertion holes 13 and the filling of resin 15 into each of the magnet insertion holes 13 are performed in a manner that cancels out a problem of this imbalanced weight.

A fan apparatus comprises a stator unit, a rotor unit comprising an impeller, and a casing that houses the stator unit and the rotor unit. The casing comprise a side wall portion that surrounds a periphery of the impeller, a base portion that holds the stator unit and the rotor unit, and a plurality of connection portions that connect the side wall portion and the base portion. The casing is formed by at least two members including a first member and a second member coupled to the first member. The first member includes at least one of the connection portions and at least part of the base portion, and the second member includes at least one of the connection portions.

A method of manufacturing a rotor core includes: acquiring individual weights of a plurality of permanent magnets to identify heavier permanent magnets and lighter permanent magnets based on a comparison of the individual weights; obtaining first to N.sup.th magnet sets by combining at least one of the heavier permanent magnets and at least one of the lighter permanent magnets into each magnet set, wherein N is a natural number equal to or greater than 2; preparing a core body configured to rotate around a predetermined rotational axis, the core body including first to N.sup.th attaching locations arranged in a circumferential direction of the rotational axis; and attaching each of the first to N.sup.th magnet sets to a different oneof the first to N.sup.th attaching locations.

A method of assembling an electric motor comprises axially translating a rotor of a rotor assembly in a first direction through a longitudinal bore of a stator, a first centering ring of the rotor assembly preventing a first end of the rotor from contacting an internal surface of the longitudinal bore; rotatably supporting a first end of the rotor assembly longitudinally extending from the rotor with a first support member; resting a second centering ring of the rotor assembly on the internal surface of the longitudinal bore; rotatably supporting a second end of the rotor assembly longitudinally extending from the rotor with a second support member; and axially translating the rotor assembly in a second direction, opposite the first direction, to place the rotor assembly in a position in which both the first centering ring and the second centering ring are outside the longitudinal bore.

A method for balancing rotors (10) of electrical machines, where each rotor (10) has a shaft (11) and at least one laminated core (12) arranged on the shaft. The method includes providing a rotor (10) that is to be balanced, providing blanks (13), with a length (l) that is smaller than an outside diameter (d) of the laminated core (12) of the rotor (10), ascertaining a magnitude and orientation of an initial unbalance of the rotor (10) and processing the blanks (13) by making a recess (15) in the respective blank (13) outside the center of gravity depending on the magnitude of the ascertained initial unbalance. The blank (13) can be mounted by fitting the recess (15) on the shaft (11) of the rotor (10) and mounting the processed blank (13) on the rotor (11) in an angular position that is dependent on the orientation of the ascertained initial unbalance.

An electrical machine includes a rotor including windings circumferentially spaced apart by rotor wedges. The electrical machine includes a rotor end plate mounted to the rotor. The rotor end plate includes an annular end plate body with an interior surface and axially opposed exterior surface. The interior surface includes a cavity for engaging the rotor. The interior surface has a base that is bounded by an inner rim and an outer rim radially opposite the inner rim. The interior surface is free of anti-rotation projections extending axially therefrom. The outer rim is free of anti-rotation features extending radially inward therefrom.

Hollow motor apparatuses and associated systems and methods for manufacturing the same are disclosed herein. In representative embodiment, a hollow motor apparatus includes a rotor assembly rotatable about a rotation axis, a stator assembly positioned adjacent to the rotor assembly and coaxially with the rotor assembly relative to the rotation axis, and a bearing assembly operably coupled to the rotor assembly. The rotor assembly has an inner portion around an opening configured to receive at least a portion of a payload. The bearing assembly is disposed outside the inner portion of the rotor assembly and is configured to maintain a position of the rotor assembly relative to the stator assembly.