DE-102024139735-A1 - Wedge for an electric motor

DE102024139735A1DE 102024139735 A1DE102024139735 A1DE 102024139735A1DE-102024139735-A1

Abstract

A rotor comprises a laminated core that defines the poles and pole shoes. The pole shoes define slots for receiving wire coils. An outer wedge is positioned within these slots. The outer wedge includes an upper section located on the rotor's outer diameter. This upper section comprises a top and a bottom surface. The top and bottom surfaces form a continuous curve that presses against the pole shoes. The top surface provides a primary seal, and the bottom surface provides a secondary seal. The outer wedge also includes a lower section that is continuously connected to the upper section and is in contact with the coil wires. The lower section comprises a winding support surface and a wedge tip surface. The winding support surface is connected to the bottom surface of the upper section. The wedge tip surface extends along the wedge's central axis to the laminated core.

Inventors

Mark R. Claywell
Brad J. Heckman
Eric F. Grimminger

Assignees

GM Global Technology Operations LLC

Dates

Publication Date: 20260513
Application Date: 20241224
Priority Date: 20241108

Claims (10)

A wedge for a rotor, the rotor comprising a laminated core defining an axis of rotation, poles, and pole shoes, the rotor defining slots for receiving wire coils, the wedge comprising: an outer wedge defining a wedge center axis perpendicular to the axis of rotation, the outer wedge being arranged in the slots, comprising: an upper section arranged on an outer diameter of the rotor, the upper section comprising: a top surface inclined away from the wedge center axis and moving radially outward and perpendicular to a rotor axis, the top surface pressing against the pole shoe to create a seal; and a bottom surface sloping toward the wedge center axis and moving radially outward and perpendicular to the rotor axis, the bottom surface sealing against the pole when a radial load is applied, the top surface and the bottom surface forming a continuous curve; and a lower section continuously connected to the upper section, comprising: a winding bearing surface connected to the bottom surface of the upper section; and a wedge tip surface, wherein the wedge tip surface extends along the wedge center axis to the laminated core, where the winding support surface and the wedge tip surface adjoin the wire coils.
Wedge after Claim 1 , wherein the outer wedge comprises a convex section located between the underside of the upper section and the winding support surface of the lower section.
Wedge after Claim 2 , further comprising lacquer distributors defined by the convex section and the pole shoes, wherein the lacquer distributors enable a lacquer to cover the wire coils and seal the spaces between the laminates forming the laminated core.
Wedge after Claim 1 , wherein the outer wedge comprises a flexible hinge connecting the underside of the upper section and the lower section of the outer wedge, the flexible hinge allowing the upper section to move independently of the lower section.
Wedge after Claim 1 , wherein the winding support surface forms an incline away from the wedge center axis and moves radially outwards and perpendicular to the rotor axis.
Wedge after Claim 1 , further comprising an inner wedge arranged in a groove of the outer wedge, wherein the inner wedge fits a contour of an inner surface of the outer wedge and a com Pressure is generated against the pole shoes and the winding contact surface.
Wedge after Claim 6 , wherein the inner wedge defines a shaped hole along an axial length of the wedge, the shaped hole increasing the absorption of the radial load and allowing an adjustable compression stiffness between adjacent poles.
Wedge after Claim 6 , furthermore comprising pockets on the inner wedge, the pockets being of different sizes to regulate stiffness over the axial length of the wedge.
Wedge after Claim 8 , wherein the pockets are located on a top side of the inner wedge, the top side of the inner wedge being arranged on the outer diameter of the rotor.
Wedge after Claim 8 , wherein the pockets are located on the sides of the inner wedge, the sides of the inner wedge being in contact with the inner surface of the outer wedge.

Description

INTRODUCTION The present disclosure relates to a wedge for an electric motor. In particular, the present disclosure relates to a wedge for a separately excited rotor in an electric motor for compressing wire coils and sealing them to the rotor in order to retain coolant therein. A separately excited synchronous motor (SESM) typically comprises a stator and a rotor. Instead of permanent magnets in the rotor, the SESM uses wire coils that generate a rotor field. The magnetic field of the rotor can therefore be adjusted by the magnitude of the current applied to the wire coils. The rotor consists of a laminated core with poles and pole shoes that form slots. The wire coils are located in the slots and wound around the poles. When an electric current is applied to the wire coils, the rotor begins to rotate at high speed. During rotation, the wire coils are subjected to radial forces and can shift. One solution is to insert a wedge into the slots. The wedge presses against the wire coils, protecting them and maintaining their alignment. While this is effective, the prior art requires an improved wedge design with a stronger seal between the wedge and the pole shoes. This would allow for the placement of additional wire coils in the slots while maintaining compression against the wire coils at high speeds. BRIEF SUMMARY OF THE INVENTION A wedge is provided for a rotor according to several aspects. The rotor comprises a laminated core that defines an axis of rotation, poles, and pole shoes, with slots for receiving wire coils. The wedge includes an outer wedge that defines a wedge center axis perpendicular to the axis of rotation. The outer wedge is positioned within the slots. The outer wedge includes an upper section located on an outer diameter of the rotor. The upper section has a top surface that slopes away from the wedge center axis, moving radially outward and perpendicular to a rotor axis. The top surface presses against the pole shoe to create a seal. The outer wedge also includes a bottom surface that slopes toward the wedge center axis, moving radially outward and perpendicular to the rotor axis. Under a radial load, the bottom surface seals against the pole shoes. The top and bottom surfaces form a continuous curve. The outer wedge also includes a lower section that is continuously connected to the upper section. The lower section comprises a winding support surface that is connected to the underside of the upper section. The lower section also includes a wedge tip surface. The wedge tip surface extends along the wedge's central axis to the laminated core. The winding support surface and the wedge tip surface are adjacent to the wire coils. In another aspect of the present disclosure, the outer wedge comprises a convex section that is arranged between the underside of the upper section and the winding support surface of the lower section. In another aspect of the present disclosure, the lacquer distributors are defined by the convex section and the pole pieces. The lacquer distributors enable a lacquer to coat the wire coils and seal the spaces between the laminates that form the laminated core. In another aspect of the present disclosure, the outer wedge comprises a flexible hinge located where the underside of the upper section and the lower section of the outer wedge are joined. The flexible hinge allows the upper section to move independently of the lower section. According to another aspect of the present disclosure, the winding support surface forms an incline away from the wedge center axis and moves radially outwards and perpendicular to the rotor axis. In another aspect of the present disclosure, the wedge also includes an inner wedge. The inner wedge is arranged in a groove of the outer wedge. The inner wedge fits the contour of the inner surface of the outer wedge and creates a compression against the pole shoes and the winding contact surface. In another aspect of the present disclosure, the inner wedge defines a formed hole along an axial length. The formed hole increases the absorption of the radial load. The formed hole also enables adjustable compression stiffness between adjacent poles. In another aspect of the present revelation, the inner wedge includes pockets. The pockets are each of different sizes in order to... To regulate stiffness across the axial length of the wedge. In another aspect of the present disclosure, the pockets are located on the upper side of the inner wedge. The upper side of the inner wedge is arranged on the outer diameter of the rotor. In another aspect of the present revelation, the pockets are located on the sides of the inner wedge. The sides of the inner wedge lie against the inner surface of the outer wedge. A wedge is provided for a rotor according to several aspects. The rotor comprises a laminated core that defines an axis of rotation, poles, and pole shoes, with slots for receiving wire coils. The wedge includes an outer wedge that defines a wedge c