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CN-121984272-A - Stepping servo motor with power-off braking function

CN121984272ACN 121984272 ACN121984272 ACN 121984272ACN-121984272-A

Abstract

The invention relates to the field of motors, in particular to a stepping servo motor with a power-losing braking function, which comprises a motor shell, a power module arranged in the motor shell, a floating braking module arranged outside the main shaft and comprising a braking disc and a magnetic coupling component, wherein the magnetic coupling component is used for establishing non-contact magnetic torque transmission connection between the main shaft and the braking disc, and the braking component is used for applying friction braking force to the braking disc driven by the magnetic coupling component and directly guiding braking torque generated by friction braking to the motor shell.

Inventors

  • ZHU WENZHANG
  • YANG LU

Assignees

  • 常州宝龙电机股份有限公司

Dates

Publication Date
20260505
Application Date
20251225

Claims (9)

  1. 1. A stepping servo motor with a power-off braking function is characterized by comprising, A motor housing (1) composed of a front end cover (12), a housing (11) and a rear end cover (13) which are connected with each other; a power module (2) arranged in the motor housing (1); The power module (2) comprises a main shaft (21) rotatably mounted on a shell, a rotor (22) is fixedly sleeved on the outer side of the main shaft (21), a stator (23) sleeved on the outer side of the rotor (22) is fixedly mounted on the inner wall of the shell (11), a floating brake module (3) is arranged on the outer side of the main shaft (21), the floating brake module (3) comprises a brake disc (34) and a magnetic coupling assembly (31), the magnetic coupling assembly (31) is used for establishing non-contact magnetic torque transmission connection between the main shaft (21) and the brake disc (34), and the brake assembly (32) is used for applying friction braking force to the brake disc (34) driven by the magnetic coupling assembly (31) and directly guiding braking torque generated by friction braking to the motor shell (1).
  2. 2. The stepping servo motor with the power-off braking function according to claim 1, wherein the floating type braking module (3) further comprises a spline shaft sleeve (33) fixedly sleeved on the outer side of the main shaft (21), and the braking disc (34) is fixedly sleeved on the outer side of the spline shaft sleeve (33).
  3. 3. The stepping servo motor with a power-failure braking function according to claim 2, wherein the motor housing (1) is composed of a front end cover (12), a housing (11) and a rear end cover (13) which are connected with each other.
  4. 4. The stepping servo motor with the power-losing braking function according to claim 3, wherein the power module (2) further comprises a rotor (22) fixedly sleeved on the outer side of the main shaft (21), and a stator (23) fixedly sleeved on the outer side of the rotor (22) is fixedly arranged on the inner wall of the shell (11).
  5. 5. The stepping servo motor with the power-losing braking function as set forth in claim 4, wherein the magnetic coupling assembly (31) comprises a first friction disk (311) fixedly installed on the inner wall of the housing (11) and sleeved on the outer side of the main shaft (21), a permanent magnet ring (312) is fixedly installed on one side, close to the brake disk (34), of the first friction disk (311), and magnetic tension coupling is formed between the permanent magnet ring (312) and the rotor (22).
  6. 6. The stepping servo motor with the power-failure braking function as set forth in claim 5, wherein the braking assembly (32) comprises a mounting disc (321) fixedly mounted on the inner wall of the housing (11) and sleeved on the outer side of the main shaft (21), and a coil (322) is fixedly mounted on one side, close to the braking disc (34), of the mounting disc (321).
  7. 7. The stepping servo motor with the power-off braking function as set forth in claim 6, wherein a plurality of braking springs (323) are fixedly arranged on one side of the mounting disc (321) close to the braking disc (34), and a second friction disc (324) matched with the first friction disc (311) is jointly arranged at the tail ends of the braking springs (323).
  8. 8. The stepping servo motor with the power-off braking function according to claim 7, wherein the main shaft (21) is rotatably mounted on the motor housing (1) through a bearing, and the rotor (22) is made of a permanent magnet material, and the surface of the rotor is subjected to multipolar magnetization to form a permanent magnetic field.
  9. 9. The stepping servo motor with the power-failure braking function according to claim 8, wherein the spline shaft sleeve (33) is sleeved on the outer side of the main shaft (21) in a key connection mode, and the brake disc (34) is made of high-carbon steel and is fixedly sleeved on the outer side of the spline shaft sleeve (33) in a spline connection mode.

Description

Stepping servo motor with power-off braking function Technical Field The invention relates to the field of motors, in particular to a stepping servo motor with a power-off braking function. Background The stepping servo motor is used as a hybrid driving element which integrates the advantages of simple open-loop control, large holding torque, high closed-loop control precision of the servo motor, good dynamic response and the like of the stepping motor, and plays a vital role in modern industrial automation. In many practical application scenarios, such as Z-axis driving, mechanical arm joints, motion modules with inclination angles, and slewing mechanisms with larger rotational inertia, when the system is suddenly powered off or stopped in an emergency, the driving motor is required to lock the load at the current position immediately and reliably, so as to prevent the sliding, slipping or unexpected movement caused by gravity, inertia and other factors, thereby ensuring equipment safety, avoiding product damage, and maintaining system precision. To meet this core safety requirement, the prior art generally employs a solution of integrating a mechanical power-off brake (commonly referred to in the industry as a band-type brake) at the non-output end (typically the tail) of the stepper servo motor. The basic working principle of the brake is 'power-on release and power-off braking', namely when a motor works normally, an electromagnetic coil in the brake is electrified, generated electromagnetic force overcomes the force of a group of pre-pressing springs, so that a dynamic friction pair and a static friction pair are separated, the restraint on a motor shaft is removed, when the system is powered off or a sudden stop signal is received, the coil is powered off, the electromagnetic force disappears instantly, the elastic force of the pre-pressing springs is released, the friction pair is pushed to be pressed rapidly, static friction moment is generated under huge positive pressure, and the motor shaft is further locked mechanically. However, through feedback on the deep parsing and long-term engineering practices of the prior art solutions, it was found that it presents a fundamental structural defect that affects the long-term reliability and accuracy retention of the motor. This drawback arises from the unreasonable design of the transmission path of the braking load (including the large axial impact forces and braking moments). Specifically, the strong axial impact force generated by the release of the spring is transmitted directly to the motor shaft rigidly connected to the armature through the armature component of the brake at the moment of actuation of the brake. This impact force is transmitted along the motor shaft and eventually is carried by the core bearings (typically deep groove ball bearings or angular contact bearings at the motor tail) that support the motor rotor for rotation. At the same time, the braking moment generated in the braking process is mainly transmitted and balanced through the motor shaft. Because the automation equipment often needs to be frequently started, stopped and positioned, the occurrence rate of braking actions is extremely high. Such continuous, high frequency axial impact loads directly act on the precision bearing, which inevitably results in early fatigue damage to the bearing raceways and rolling elements, such as brinell indentation, increased wear, etc. The direct consequences of this are increased bearing play, reduced rotational accuracy, increased operating noise and vibrations. From the system level, the prior art scheme is essentially to carry out rigid mechanical coupling on a braking function module which bears high impact and high abrasion and a motor core moving part (rotor, main shaft and bearing) which requires high precision, high stability and long service life. This coupling, like having a sprint runner (brake) and a heart surgeon (precision bearing) share a set of nervous systems and frequently strike each other, must be done in the long term at the expense of surgeon stability (bearing accuracy) and longevity. The motor has the advantages that the service life of the whole motor is obviously shortened, the maintenance cost is increased, the positioning precision, the repeated positioning precision and the dynamic response performance of the whole servo transmission system are gradually deteriorated, and the severe requirement of high-end precision equipment on long-term stability is difficult to meet. In addition, the traditional integrated mode of the brake and the motor in a superposition mode also brings the problems of axial size increase, complex structure, mutual interference of heat dissipation paths and the like. The heat generated by friction during braking is liable to affect the temperature rise of the motor windings and the lubrication of the bearings by conduction and radiation. Therefore, how to reconstruct the transmission pat