CN-114400827-B - Multipolar magnetic circuit friction brake without axial magnetic leakage

Abstract

The invention discloses a multipolar magnetic circuit friction brake without axial magnetic leakage, which comprises a rotor, a pressing plate, an armature and a stator, wherein a spring and an air gap are arranged between the armature and the stator, a multi-polarity solenoid coil is embedded in the stator, the multi-polarity solenoid coil consists of a plurality of groups of solenoid coils, the solenoid coils of each group have the same structure and are uniformly distributed in the circumferential direction, and the current directions of two adjacent groups of solenoid coils are opposite to each other to form a pair of poles. The invention adopts the multi-polarity solenoid coil, and axial leakage magnetic flux generated by the multi-polarity solenoid coil counteracts due to positive and negative phases, and the axial magnetic flux-free effect is presented along the axial direction, thereby avoiding the reduction of the precision of the magnetic encoder axially installed by the traditional brake due to axial magnetic leakage.

Inventors

• LI DAYONG

Assignees

• 南京埃斯顿自动化股份有限公司
• 南京埃斯顿自动化股份有限公司

Dates

Publication Date

20260421

Application Date

20211222

Priority Date

20211222

Claims (4)

1. 1. The multipolar magnetic circuit friction brake without axial magnetic leakage comprises a rotor, a pressing plate, an armature and a stator, wherein a spring and an air gap are arranged between the armature and the stator, and the multipolar magnetic circuit friction brake is characterized in that a multipolar solenoid coil is embedded in the stator, the multipolar solenoid coil consists of a plurality of groups of solenoid coils, the solenoid coils of each group have the same structure and are uniformly distributed in the circumferential direction, each group of solenoid coils comprises 2 single-polarity solenoid coils, the current directions of two adjacent groups of solenoid coils are opposite to form a pair of poles, an annular groove is formed in the stator, a plurality of raised iron cores are arranged in the annular groove, and the single-polarity solenoid coils are embedded in the annular groove and sleeved on the raised iron cores; the stator is made of non-magnetic metal material, and the convex iron core is made of magnetic metal material.
2. 2. The multipolar magnetic circuit friction brake free of axial leakage according to claim 1, wherein the cross-sectional shape of the single-polarity solenoid coil is circular, elliptical, trapezoidal or polygonal.
3. 3. The multipolar magnetic circuit friction brake free of axial leakage according to claim 1, wherein the cross-sectional shape of the protruding iron core is adapted to the cross-section of the single polarity solenoid coil.
4. 4. The multipolar magnetic circuit friction brake free of axial leakage according to claim 1, wherein the protruding iron core is embedded in the annular groove of the stator when cast.

Description

Multipolar magnetic circuit friction brake without axial magnetic leakage Technical Field The invention relates to the technical field of electromagnetic brakes, in particular to a multipolar magnetic circuit friction brake without axial magnetic leakage. Background In order to realize the power-off maintaining function, a brake is required to be installed on a motor shaft of the servo motor, and one common brake is an electromagnetic friction brake. The existing electromagnetic friction brake consists of a rotor, a pressing plate, an armature and a stator, wherein a unipolar solenoid coil is embedded in the stator, and a spring and an air gap are arranged between the armature and the stator. After the brake is electrified, the unipolar solenoid coil generates a magnetic field, the armature overcomes the spring force of the spring and is attracted to the stator, and the rotor can rotate freely. After the brake is powered off, the armature is pressed on the pressing plate by the rotor under the action of the spring force of the spring, so that the brake is realized. The armature 4, the stator 2 and the unipolar solenoid coil 3 constitute a main magnetic circuit of the brake. Referring to fig. 1, a main magnetic flux 5 generated by a single-polarity solenoid coil 3 passes through a stator inner ring 21, an armature 4 and a stator outer ring 22 to form a closed circuit. The main magnetic flux 5 is radially distributed in the armature 4, and the direction changes with the positive and negative electrode connection mode of the brake. In addition to the main magnetic circuit, the unipolar solenoid coil 3 also generates an axial leakage flux 6, see fig. 2, which leakage flux 6 is axially distributed in the brake bore, passing along the main shaft where the brake is mounted to the shaft end. An encoder is arranged at the shaft end of a rotor of the servo motor and used for measuring angles and rotating speeds to serve as feedback elements, if the magnetic encoder is arranged at the shaft end, the magnetic leakage of the brake can affect the working point of the encoder, and especially when the brake is randomly connected in forward and reverse directions, the axial magnetic leakage generated by the brake is random, so that the accuracy of the magnetic encoder is seriously affected. Disclosure of Invention In order to solve the technical problems, the invention provides a multipolar magnetic circuit friction brake without axial magnetic leakage. The technical scheme adopted by the invention is as follows: A multipolar magnetic circuit friction brake without axial magnetic leakage comprises a rotor, a pressing plate, an armature and a stator, wherein a spring and an air gap are arranged between the armature and the stator, a multipolar solenoid coil is embedded in the stator, the multipolar solenoid coil consists of a plurality of groups of solenoid coils, the solenoid coils of each group have the same structure and are uniformly distributed in the circumferential direction, and the current directions of two adjacent groups of solenoid coils are opposite to each other to form a pair of poles. Further, each set of solenoid coils comprises at least 1 single polarity solenoid coil. Further, the cross-sectional shape of the unipolar solenoid coil is circular, elliptical, trapezoidal, or polygonal. Further, an annular groove is formed in the stator, a plurality of protruding iron cores are arranged in the annular groove, and the unipolar solenoid coil is embedded in the annular groove and sleeved on the protruding iron cores. Further, the cross-sectional shape of the protruding iron core is adapted to the cross-section of the unipolar solenoid coil. Further, the stator is made of a non-magnetically conductive metal material, and the protruding iron core is made of a magnetically conductive metal material. Further, the protruding iron core is embedded in the annular groove of the stator at the time of casting. The invention has the beneficial effects that: 1. The invention adopts the multi-polarity solenoid coil, and axial leakage magnetic flux generated by the multi-polarity solenoid coil counteracts due to positive and negative phases, and the axial magnetic flux-free effect is presented along the axial direction, thereby avoiding the reduction of the precision of the magnetic encoder axially installed by the traditional brake due to axial magnetic leakage. 2. The invention adopts the stator made of non-magnetic conductive metal material, the convex iron core made of magnetic conductive metal material, the main magnetic circuit structure generated by the multi-polarity solenoid coils arranged on the convex iron core changes the magnetic circuit direction in the traditional armature, and the main magnetic flux generated by one group of solenoid coils enters the convex iron core of the adjacent other group through the convex iron core and the armature of the group to form a closed loop. The stator made of non-magnetic meta