A servo motor with a self-locking function

Abstract

The present invention discloses a servo motor with a self-locking function, which includes a motor rotor assembly, a motor stator assembly and an electromagnetic lock; the integrated electromagnetic locking stator in the electromagnetic lock is cooperated with the outer ring of the rear bearing and fixedly connected to the rear end of the motor housing in the motor stator assembly, the front end of the transfer shaft in the electromagnetic lock is drivingly connected to the rear end of the rotor shaft in the motor rotor assembly, and the electromagnetic lock rotor in the electromagnetic lock is positioned and installed on the transfer shaft; during the operation of the servo motor, the gap between the electromagnetic lock rotor and the integrated electromagnetic locking stator is a fixed value. The servo motor with a self-locking function proposed by the present invention has the advantages of reliable operation, small size and light weight.

Description

Technical Field

[0001] The present invention relates to an electric motor for commercial airliners and industrial electric servo drive fields, and particularly to a permanent magnet synchronous motor for an electromechanical actuation system integrated with an electric motor and an electromagnetic lock, belonging to the servo drive field. Background Art

[0002] Electromechanical actuation systems are widely used in electromechanical servo systems due to their advantages such as high dynamic response, high reliability, and high power density. As a servo power component, the electric motor together with a reduction device (gearbox, planetary roller screw, etc.) constitutes an electromechanical actuator. The displacement of the electromechanical actuator (indirect measurement) and the angular position signal of the servo motor are measured through a resolver or a magnetic encoder, and a closed-loop control algorithm is run in the control driver to control the operation of the electromechanical actuator.

[0003] Currently, servo motors with self-locking functions are gradually being applied to the position control link of electric actuators because they can accurately control the position of the actuator. However, there are many disadvantages:

[0004] (1) Currently, the integration of the electromagnetic lock and the servo motor is mainly through simple external connections. The interface connection between the electromagnetic lock and the motor occupies a certain space, affecting the volume of the mechanism.

[0005] (2) The clearance of the electromagnetic lock needs to be ensured by adding or reducing adjustment gaskets at the connection interface between the electromagnetic lock and the servo motor. This not only increases the debugging difficulty, but also makes it difficult to ensure the effective clearance of the electromagnetic lock.

[0006] (3) Since the servo motor uses a wave spring to provide the axial preload of the motor, when the rotor shaft of the servo motor axially moves, the electromagnetic lock may fail due to an excessive actual clearance. Summary of the Invention

[0007] The purpose of the present invention is to overcome the above defects and provide a servo motor with a self-locking function, which solves the technical problems of large space occupation and difficult debugging of the electromagnetic lock clearance of the existing servo motor, so that during the operation of the servo motor, the clearance between the rotor of the electromagnetic lock and the integrated electromagnetic lock stator is a fixed value, and it has the advantages of reliable operation, small volume, and light weight.

[0008] To achieve the above invention purpose, the present invention provides the following technical solutions:

[0009] A servo motor with a self-locking function, comprising a motor rotor assembly, a motor stator assembly, and an electromagnetic lock;

[0010] The motor stator assembly includes a motor housing and a motor stator fixedly connected inside the motor housing; the motor rotor assembly is arranged inside the motor stator assembly, and the motor rotor assembly includes a rotor shaft, a motor rotor, a front bearing and a rear bearing mounted on the rotor shaft. The outer ring of the front bearing is fitted with the motor housing, and the front bearing and the rear bearing are respectively located in front of and behind the motor rotor.

[0011] The electromagnetic lock includes an integrated electromagnetic lock stator, an electromagnetic lock rotor and a transfer shaft; the integrated electromagnetic lock stator is fitted with the outer ring of the rear bearing, the front end of the integrated electromagnetic lock stator is fixedly connected to the rear end of the motor housing, the front end of the transfer shaft is drivingly connected to the rear end of the rotor shaft, and the electromagnetic lock rotor is positioned and mounted on the transfer shaft.

[0012] During the operation of the servo motor, the gap between the electromagnetic lock rotor and the integrated electromagnetic lock stator is a fixed value.

[0013] Further, the electromagnetic lock further includes a transfer shaft support frame and a transfer shaft bearing;

[0014] The transfer shaft support frame is a hollow structure, and the inner and outer rings of the transfer shaft bearing are respectively fitted with the transfer shaft and the inner wall of the transfer shaft support frame; the electromagnetic lock rotor is located inside the transfer shaft support frame, and the transfer shaft bearing is located behind the electromagnetic lock rotor.

[0015] The inner wall of the transfer shaft support frame is provided with an inwardly protruding transfer shaft bearing limit boss for limiting the front end face of the transfer shaft bearing.

[0016] The front end of the transfer shaft support frame is fixedly connected to the rear end of the integrated electromagnetic lock stator.

[0017] The front end of the electromagnetic lock stator is provided with an inward circular blind hole for the installation and limitation of the rear bearing.

[0018] Further, denote the axial distance from the transfer shaft bearing limit boss in the transfer shaft support frame to the rear end face of the integrated electromagnetic lock stator as H1, the axial distance from the transfer shaft bearing limit boss in the transfer shaft support frame to the rear end face of the electromagnetic lock rotor as L1, the axial width of the electromagnetic lock rotor as L2, and the axial width of the integrated electromagnetic lock stator as L3;

[0019] The gap d between the electromagnetic lock rotor and the integrated electromagnetic lock stator is d = H1 - L1 - L2 - L3;

[0020] Before the assembly of the servo motor, by adjusting the values of H1, L1, L2 and L3, d is made to reach a predetermined value.

[0021] Further, d = 0.15 mm.

[0022] Further, the integrated electromagnetic lock stator includes an integrally formed motor end cover and an electromagnetic lock stator.

[0023] Furthermore, a first semi-cylindrical boss is provided at the front end of the adapter shaft, and a second semi-cylindrical boss is provided at the rear end of the rotor shaft. The first semi-cylindrical boss cooperates with the second semi-cylindrical boss to achieve the transmission connection between the front end of the adapter shaft and the rear end of the rotor shaft.

[0024] Furthermore, the side surfaces of the first semi-cylindrical boss and the second semi-cylindrical boss both include a flat surface and an arc surface;

[0025] When the first semi-cylindrical boss cooperates with the second semi-cylindrical boss, the flat surface of the first semi-cylindrical boss contacts the flat surface of the second semi-cylindrical boss. There is an axial gap between the front end face of the first semi-cylindrical boss and the rear end face of the rotor shaft, and there is an axial gap between the rear end of the second semi-cylindrical boss and the front end face of the adapter shaft;

[0026] The axial gap is greater than the maximum displacement of the rotor shaft during axial movement.

[0027] Furthermore, the adapter shaft support frame and the adapter shaft bearing are in a transition fit, and the adapter shaft and the adapter shaft bearing are in an interference fit.

[0028] Furthermore, it also includes a wave spring;

[0029] The rear end of the wave spring contacts the front bearing, and the front end of the wave spring contacts the motor housing. When the front end of the rotor shaft is connected to an external mechanism, if there is a forward force on the rotor shaft from the external mechanism, the wave spring is compressed to make the rotor shaft move forward. At this time, the gap between the electromagnetic lock rotor and the integrated electromagnetic lock stator can remain unchanged. At this time, the rotor shaft is limited by the inner circular blind hole at the front end of the electromagnetic lock stator through the rear bearing.

[0030] Furthermore, the outer diameters of the motor housing, the adapter shaft support frame, and the integrated electromagnetic lock stator are equal.

[0031] The present invention has the following beneficial effects compared with the prior art:

[0032] (1) The present invention creatively proposes a structural scheme of integrating a servo motor and an electromagnetic lock, effectively utilizing the structural advantages of the servo motor to save connection space and improve the compactness and integration of the self-locking servo motor structure;

[0033] (2) The present invention adopts the method of designing the motor rotor and the electromagnetic lock with a split shaft, and at the same time designs the entire drive shaft system, that is, the electromagnetic lock rotor is installed on the adapter shaft, and the adapter shaft and the rotor shaft are driven separately. This effectively prevents the situation that the effective gap of the electromagnetic lock is affected by the movement of the rotor, resulting in the abnormal operation of the electromagnetic lock; the present invention not only prevents the front bearing or the rear bearing from being stuck and failing due to mechanical limit during the operation of the motor caused by the thermal expansion of the motor rotor, but also ensures that the gap of the electromagnetic lock is no longer affected during the movement of the rotor shaft, effectively improving the operation reliability of the motor with self-locking function;

[0034] (3) The present invention integrates the electromagnetic lock rotor with the motor end cover to form an integrated electromagnetic lock rotor, achieving the compactness of the motor structure and reducing the volume and weight of the self-locking servo motor.

[0035] (4) The present invention designs the transmission structure between the motor and the electromagnetic lock interface structure, that is, between the rotor shaft and the adapter shaft, so that the clearance of the electromagnetic lock can be ensured through one-time assembly without the need to additionally add gaskets for adjustment, improving the operation reliability and assembly convenience of the servo motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall servo motor in a preferred embodiment of the present invention;

[0037] Figure 2 It is a schematic diagram of the internal installation of the servo motor in a preferred embodiment of the present invention;

[0038] Figure 3 It is a schematic diagram of the total assembly of the motor rotor and the electromagnetic lock in a preferred embodiment of the present invention;

[0039] Figure 4 It is a schematic diagram of the installation of the electromagnetic lock in a preferred embodiment of the present invention;

[0040] Figure 5 It is a schematic diagram of the connection between the adapter shaft and the rotor shaft in a preferred embodiment of the present invention;

[0041] Figure 6 is Figure 5 a cross-sectional view taken along the A-A section;

[0042] Among them, 1 - adapter shaft support frame; 2 - adapter shaft; 3 - electromagnetic lock; 4 - motor stator; 5 - rotor shaft; 6 - resolver; 7 - adapter shaft bearing; 8 - front bearing; 9 - rear bearing; 10 - motor rotor; 11 - wave spring; 3-1 - integrated electromagnetic lock rotor; 3-2 - electromagnetic lock rotor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] The features and advantages of the present invention will become clearer and more definite as the following detailed description of the present invention proceeds.

[0044] The special term "exemplary" herein means "serving as an example, embodiment, or illustration". Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0045] According to the working characteristics of the servo motor electromagnetic lock, the present invention integrates the servo motor and the electromagnetic lock, which can not only save the installation space, improve the installation and adjustment efficiency of the electromagnetic lock gap, but also prevent the axial movement of the motor from affecting the effective gap of the electromagnetic lock, greatly reducing the volume of the servo motor, improving the structural compactness and enhancing the operation reliability of the servo motor.

[0046] As Figures 1 to 6 shown, a servo motor with a self-locking function according to the present invention includes a motor rotor assembly, a motor stator assembly and an electromagnetic lock;

[0047] The motor stator assembly and the motor rotor assembly are the main parts for the servo motor to realize the electro-mechanical energy conversion. The motor stator assembly includes a motor housing and a motor stator 4 fixedly connected inside the motor housing, where the motor stator 4 includes a three-phase winding and an iron core; the motor rotor assembly includes a rotor shaft 5, a motor rotor 10 mounted on the rotor shaft 5, a front bearing 8 and a rear bearing 9, where the motor rotor 10 includes a stainless steel sleeve and a permanent magnet from outside to inside.

[0048] The rear bearing 9 is fitted and installed with the integrated electromagnetic lock stator 3-1, and a transmission connection is adopted between the transfer shaft 2 and the rotor shaft 5, as Figure 6 shown. The rotor shaft 5 can axially move, and when the rotor shaft 5 axially moves, the transfer shaft 2 will not move with the rotor shaft 5 and can remain axially stationary, effectively ensuring that the gap between the integrated electromagnetic lock stator 3-1 and the electromagnetic lock rotor 3-2 remains strictly unchanged. The transfer shaft 2 and the transfer shaft bearing 7 are in interference fit, and the transfer shaft bearing 7 and the transfer shaft support frame 1 are in transitional fit.

[0049] Before assembly, the gap between the electromagnetic lock rotor 3-2 and the integrated electromagnetic lock stator 3-1 is controlled by calculating the dimension chain. The specific method is: measuring the distance H1 between the transfer shaft bearing limit boss provided on the transfer shaft support frame 1 and the integrated electromagnetic lock stator 3-1, measuring the installation distance L1 between the transfer shaft bearing limit boss in the transfer shaft support frame 1 and the electromagnetic lock rotor 3-2, the width L2 of the electromagnetic lock rotor 3-2, and the width L3 of the integrated electromagnetic lock stator 3-1, ensuring that the relationship of several dimensions is H1 - L1 - L2 - L3 = 0.15 mm. By controlling the dimensions of H1, L1, L2 and L3, and then through assembly, the gap of the electromagnetic lock 3 can be controlled to be 0.15 mm without other adjustments.

[0050] The front end of the transfer shaft is provided with a first semi-cylindrical boss, and the rear end of the rotor shaft is provided with a second semi-cylindrical boss. The first semi-cylindrical boss and the second semi-cylindrical boss cooperate to realize the transmission connection between the front end of the transfer shaft and the rear end of the rotor shaft. When cooperating, the plane of the first semi-cylindrical boss contacts the plane of the second semi-cylindrical boss, as Figure 2The shown rotor shaft 5 is axially preloaded by a wave spring 11. When the rotor shaft 5 axially creeps forward due to excessive external load, the rotor shaft 5 will overcome the friction force between the planes of the two semi-cylindrical bosses and creep in the axial clearance between the adapter shaft 2. At this time, the adapter shaft 2 remains stationary, and the position of the electromagnetic lock rotor 3-2 remains unchanged. Since the front end of the integrated electromagnetic lock stator 3-1 is fixedly connected to the rear end of the motor housing and the position of the motor housing remains unchanged, the position of the integrated electromagnetic lock stator 3-1 remains unchanged, that is, the clearance between the integrated electromagnetic lock stator 3-1 and the electromagnetic lock rotor 3-2 remains unchanged. Therefore, the clearance of the electromagnetic lock 3 does not change with the axial creep of the rotor shaft 5, improving the reliability of the electromagnetic lock 3.

[0051] The electromagnetic lock 3 is arranged inside the motor, eliminating the need for the traditional method of adjusting the clearance with gaskets for the electromagnetic lock, improving the efficiency of electromagnetic lock clearance debugging. Specifically, the electromagnetic lock 3 is located at the rear end of the rotor shaft 5, and the integrated electromagnetic lock stator 3-1 is an integrated combination of a traditional motor end cover and an electromagnetic lock stator. The resolver 6 is installed with an interference fit on the rotor shaft and mounted on the front end face of the stator 4.

[0052] The rear end of the front bearing 8 is limited by the first step surface provided on the rotor shaft 5, the front end of the motor rotor 10 is limited by the second step surface provided on the rotor shaft 5, the front end of the rear bearing 9 is limited by the third step surface provided on the rotor shaft 5. The inner surface of the electromagnetic lock stator 3-1 is provided with a circular blind hole inward at the front end and a limiting surface, and the rear end of the rear bearing 9 is limited by the blind hole limiting surface of the electromagnetic lock stator 3-1. The front bearing 8, the rear bearing 9, and the rotor 10 are all in interference fit with the rotor shaft 5 and are relatively stationary.

[0053] The servo motor of the present invention is assembled in the following order:

[0054] (1) Install the motor rotor 10, the front bearing 8, the rear bearing 9, and the wave spring 11 on the rotor shaft 5;

[0055] (2) Install the assembly assembled in step (1) into the motor stator 4;

[0056] (3) Fit the integrated electromagnetic lock stator 3-1 with the outer ring of the rear bearing 9 and fixedly connect the integrated electromagnetic lock stator 3-1 to the motor housing;

[0057] (4) Install the adapter shaft bearing 7 at the rear end of the adapter shaft 2;

[0058] (5) Install the adapter shaft support frame 1 outside the adapter shaft bearing 7 and limit the adapter shaft bearing 7 using the adapter shaft bearing limiting boss provided on the adapter shaft support frame 1;

[0059] (6) Install the electromagnetic lock rotor 3-2 on the adapter shaft 2 and make the adapter shaft 2 drive-connected to the rotor shaft 5;

[0060] (7) Fix the front end of the adapter shaft support frame 1 to the rear end of the integrated electromagnetic lock rotor 3-1.

[0061] The process for the servo motor of the present invention to achieve the self-locking function is as follows:

[0062] First, control the dimensions of H1, L1, L2, and L3. Through assembly, make the gap between the integrated electromagnetic lock rotor 3-1 and the electromagnetic lock rotor 3-2 in the electromagnetic lock 3 be 0.15 mm.

[0063] When the servo motor starts to work, a fixed gap is maintained between the integrated electromagnetic lock rotor 3-1 and the electromagnetic lock rotor 3-2 in the electromagnetic lock 3.

[0064] When the servo motor stops working, an electromagnetic attraction force is generated between the electromagnetic lock rotor 3-2 and the integrated electromagnetic lock rotor 3-1 in the electromagnetic lock 3. The spring piece in the electromagnetic lock rotor 3-2 is adsorbed onto the integrated electromagnetic lock rotor 3-1, and there is no relative displacement in the installation position between the electromagnetic lock rotor 3-2 and the adapter shaft 2, and the position of the adapter shaft 2 remains unchanged, realizing the locking of the servo motor rotor shaft 5.

[0065] The servo motor of the present invention has the following characteristics:

[0066] (1) Integrated motor design: Integrate the electromagnetic lock rotor with the motor end cover to form the integrated electromagnetic lock rotor 3-1, realizing the compactness of the motor structure and reducing the volume and weight of the self-locking servo motor.

[0067] (2) Optimized design of the motor electromagnetic lock assembly process: Design the interface structure between the motor and the electromagnetic lock, ensuring that the gap of the integrated electromagnetic lock 3 can be guaranteed through one-time assembly without the need to additionally increase shims for adjustment. It can be ensured through part dimensions and tolerances, eliminating the gap adjustment link, and improving the operation reliability and assembly convenience of the servo motor.

[0068] (3) Reliable structural design for the axial movement of the motor rotor: When the motor rotor 10 axially moves in the direction of the wave spring 11, it not only prevents the front bearing 8 or the rear bearing 9 from being stuck due to the thermal expansion of the rotor 10 during motor operation, but also ensures that the gap of the integrated electromagnetic lock 3 is not affected during the axial movement of the rotor 10, effectively improving the operation reliability of the motor with self-locking function.

[0069] The present invention has been described in detail above in combination with specific embodiments and exemplary examples. However, these descriptions should not be construed as limitations on the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications, or improvements can be made to the technical solutions and their implementation manners of the present invention, and these all fall within the scope of the present invention. The protection scope of the present invention is subject to the appended claims.

[0070] The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A servo motor with a self-locking function, characterized in that, It includes a motor rotor assembly, a motor stator assembly and an electromagnetic lock; The motor stator assembly includes a motor housing and a motor stator fixedly connected inside the motor housing; the motor rotor assembly is arranged inside the motor stator assembly, and the motor rotor assembly includes a rotor shaft (5), a motor rotor mounted on the rotor shaft (5), a front bearing (8) and a rear bearing (9). The outer ring of the front bearing (8) is fitted with the motor housing, and the front bearing (8) and the rear bearing (9) are respectively located in front of and behind the motor rotor; The electromagnetic lock includes an integrated electromagnetic lock stator (3-1), an electromagnetic lock rotor (3-2) and a transfer shaft (2); the integrated electromagnetic lock stator (3-1) is fitted with the outer ring of the rear bearing (9), the front end of the integrated electromagnetic lock stator (3-1) is fixedly connected to the rear end of the motor housing, the front end of the transfer shaft (2) is drivingly connected to the rear end of the rotor shaft (5), and the electromagnetic lock rotor (3-2) is positioned and mounted on the transfer shaft (2); During the operation of the servo motor, the gap between the electromagnetic lock rotor (3-2) and the integrated electromagnetic lock stator (3-1) is a fixed value; The front end of the transfer shaft (2) is provided with a first semi-cylindrical boss, and the rear end of the rotor shaft (5) is provided with a second semi-cylindrical boss. The first semi-cylindrical boss and the second semi-cylindrical boss cooperate to realize the driving connection between the front end of the transfer shaft (2) and the rear end of the rotor shaft (5); both the side surfaces of the first semi-cylindrical boss and the second semi-cylindrical boss include a plane and an arc surface; when the first semi-cylindrical boss and the second semi-cylindrical boss cooperate, the plane of the first semi-cylindrical boss contacts the plane of the second semi-cylindrical boss, there is an axial gap between the front end face of the first semi-cylindrical boss and the rear end face of the rotor shaft (5), and there is an axial gap between the rear end of the second semi-cylindrical boss and the front end face of the transfer shaft (2); the said axial gap is greater than the maximum displacement of the axial movement of the rotor shaft (5).

2. A servo motor with a self-locking function according to claim 1, characterized in that, The electromagnetic lock further includes a transfer shaft support frame (1) and a transfer shaft bearing (7); The transfer shaft support frame (1) is a hollow structure, and the inner ring and the outer ring of the transfer shaft bearing (7) are respectively fitted with the transfer shaft (2) and the inner wall of the transfer shaft support frame (1); the electromagnetic lock rotor (3-2) is located inside the transfer shaft support frame (1), and the transfer shaft bearing (7) is located behind the electromagnetic lock rotor (3-2); The inner wall of the transfer shaft support frame (1) is provided with an inwardly protruding transfer shaft bearing limit boss for limiting the front end face of the transfer shaft bearing (7); The front end of the transfer shaft support frame (1) is fixedly connected to the rear end of the integrated electromagnetic lock stator (3-1).

3. A servo motor with a self-locking function according to claim 1, characterized in that, Denote the axial distance from the transfer shaft bearing limit boss in the transfer shaft support frame (1) to the rear end face of the integrated electromagnetic lock stator (3-1) as H1, the axial distance from the transfer shaft bearing limit boss in the transfer shaft support frame (1) to the rear end face of the electromagnetic lock rotor (3-2) as L1, the axial width of the electromagnetic lock rotor (3-2) as L2, and the axial width of the integrated electromagnetic lock stator (3-1) as L3; The gap d between the electromagnetic lock rotor (3-2) and the integrated electromagnetic lock stator (3-1) is d = H1 - L1 - L2 - L3; Before the assembly of the servo motor, by adjusting the values of H1, L1, L2 and L3, d is made to reach a predetermined value.

4. A servo motor with a self-locking function according to claim 3, characterized in that, d = 0.15 mm.

5. A servo motor with a self-locking function according to claim 1, characterized in that, The integrated electromagnetic locking rotor (3-1) includes an integrally formed motor end cover and an electromagnetic locking rotor.

6. A servo motor with a self-locking function according to claim 2, characterized in that, There is an interference fit between the adapter shaft support frame (1) and the adapter shaft bearing (7), and an interference fit between the adapter shaft (2) and the adapter shaft bearing (7).

7. A servo motor with a self-locking function according to claim 1, characterized in that, It also includes a wave spring (11); The rear end of the wave spring (11) contacts the front bearing (8), and the front end of the wave spring (11) contacts the motor housing. When the front end of the rotor shaft (5) is connected to an external mechanism, if there is a forward acting force on the rotor shaft (5) from the external mechanism, the wave spring (11) is compressed to cause the rotor shaft (5) to move forward, and at this time the gap between the electromagnetic lock rotor (3-2) and the integrated electromagnetic locking rotor (3-1) remains unchanged.

8. A servo motor with a self-locking function according to claim 2, characterized in that, The outer diameters of the motor housing, the adapter shaft support frame (1), and the integrated electromagnetic locking rotor (3-1) are equal.

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