CN100402206C - Intelligent high-speed machining electric spindle with controllable preload - Google Patents

Abstract

The pretightening force controllable intelligent high-speed machining electric spindle relates to a spindle unit equipment for high-speed machining of CNC machine tools. The electric spindle is composed of a mechanical part and an electric control part. The mechanical part includes: a spindle (1), a motor (2) , rolling bearing (3), actuator (9), linear bearing (10), electric control part includes: encoder (4), single chip microcomputer (5), switching power amplifier (6), proportional solenoid valve (7), hydraulic oil Station (8); the motor (2) is installed in the middle of the main shaft, the front and rear ends of the main shaft are supported by rolling bearings (3), the rolling bearings (3) at the rear end of the main shaft are supported on linear bearings (11), and the actuator (9) Located on the rolling bearing (3) at the rear end of the main shaft; the encoder (4) is the signal input end of the electronic control part, located on the side of the front end of the main shaft, and sends the collected signal of the main shaft to the single-chip microcomputer (5) for processing, and the proportional solenoid valve is electronically controlled Part of the signal output end, the proportional solenoid valve is connected with the actuator through the constant pressure oil circuit.

Description

Intelligent high-speed machining electric spindle with controllable preload

technical field

The invention relates to a spindle unit equipment for high-speed machining of a numerical control machine tool, which belongs to the technical field of mechanical and electrical integration equipment manufacturing.

Background technique

During the rough machining of the electric spindle in high-speed machining, the cutting speed is low, but the cutting volume is large, and the cutting vibration force of the tool is large, which requires the electric spindle to output a large torque. At this time, the electric spindle system requires a large pre-tightening force to increase the support. Rigidity and support damping, to resist the forced vibration brought by the large exciting force and the self-excited vibration caused by the cutting process of the workpiece; during finishing machining, the cutting speed is high, but the cutting amount is small, and the electric spindle is required to output high power. As the rotating speed increases, the temperature of the rolling bearing will rise sharply. At this time, it is hoped that the preload of the bearing should be reduced as much as possible under the premise of meeting the dynamic characteristics of the spindle system.

At present, the size of the constant pressure pretightening force of the traditional electric spindle is comprehensively determined by taking into account the two factors of low speed, high torque and high speed and high power. The ability of forced vibration and self-excited vibration is weak, which often shows that the remaining vibration marks on the machined surface of the workpiece are relatively large; for the high-speed section, the pre-tightening force is too large, and the temperature rise of the bearing is too high, which restricts the high-speed motorized spindle and shortens the The service life of the bearing will reduce the rotation accuracy of the electric spindle.

Contents of the invention

Technical problem: Aiming at the existing problems in the vibration control and pre-tightening force design of the traditional electric spindle, the present invention proposes a controllable pre-tightening force intelligent high-speed machining electric spindle, which is a hybrid of elastic elements and hydraulic actuators. The new type of electric spindle with pre-tightening method is intelligently controllable through the pre-tightening force of the electric spindle, so as to obtain an electric spindle with excellent dynamic quality in the entire working speed range of low-speed high-torque section and high-speed high-power section.

Technical solution: The technical solution adopted in the present invention is: use a spring-hydraulic hybrid pre-tightening force actuator to replace the traditional electric spindle spring single pre-tightening force; The components of the device are: photoelectric encoder speed sensor-D/A converter-digital controller-power amplifier-hydraulic proportional solenoid valve-hydraulic actuator-electric spindle rolling bearing, etc.; The front-end element of the force-applying electromechanical device is connected to the end of the main shaft with a photoelectric coded speed sensor to measure the rotational speed of the main shaft end. The axial pre-tightening force hydraulically actuates the force-applying electromechanical device to control the hydraulic actuator of the end element and the rear bearing of the electric spindle. It can be connected with the spring to realize the intelligent control of the pre-tightening force.

Structurally, the pretightening force controllable intelligent high-speed machining electric spindle is composed of a mechanical part and an electric control part. The mechanical part includes: spindle, motor, rolling bearing, actuator, linear bearing, and the electric control part includes: encoder, Single-chip microcomputer, switching power amplifier, proportional solenoid valve, hydraulic oil station; the motor is installed in the middle of the main shaft, the front and rear ends of the main shaft are supported by rolling bearings, the rolling bearings at the rear end of the main shaft are supported on linear bearings, and the actuator is located on the rolling bearings at the rear end of the main shaft; The encoder is the signal input terminal of the electronic control part, located on the side of the front end of the main shaft, and sends the collected signal of the main shaft to the single-chip microcomputer for processing. The proportional solenoid valve is the signal output terminal of the electronic control part. The actuators are connected. The output terminal of the encoder is connected to the input terminal "P1.1" of the single-chip microcomputer, the output terminal "P1.3" of the single-chip computer is connected to the input terminal "Hin, Lin" of the switching power amplifier, the output terminal of the switching power amplifier is connected to the proportional solenoid valve, and the hydraulic oil station The output terminal is connected to the input terminal of the proportional solenoid valve. The actuator is an oil chamber with a pre-tightening spring inside. The oil chamber is connected to the proportional solenoid valve through a pipeline. The two ends of the pre-tightening spring are respectively supported on the two bearing sleeves of the linear bearing.

The analog signal of the rotor speed of the electric spindle is measured by the photoelectric coding speed sensor, and the analog signal is converted into a digital signal by the A/D conversion module, which is input to the single-chip controller, and the proportional electromagnetic corresponding to the corresponding speed is read in the data memory through the look-up algorithm. The valve controls the optimal current, and then through the D/A conversion module, the digital signal is converted into an analog signal, and the amplified current is output by the power amplifier to control the proportional solenoid valve, and the hydraulic cylinder (used together with the spring preload) applies axial force to the bearing Preload, in order to realize the intelligent vibration control of optimal preload of high-speed motorized spindle.

At the highest speed, the preload is provided by the elastic element. When the speed is low, the control oil pressure applies the preload through the hydraulic cylinder piston (used together with the elastic element) to achieve the best preload suitable for the speed. The new electro-spindle unit technology with excellent dynamic quality over the entire operating speed range.

The pretightening force controllable intelligent high-speed machining electric spindle of the present invention has the working process as follows: the electric spindle adopts a mixed pretightening method of elastic elements and hydraulic actuators, with the help of speed sensor-controller-amplifier-hydraulic actuator - The preload controllable open-loop system of the electric spindle, at the highest speed, the preload is provided by the elastic element, when the speed is low, the control oil pressure applies the preload through the hydraulic cylinder piston (used together with the elastic element) Force, in order to achieve the best preload value suitable for the speed, so as to obtain an electric spindle with excellent dynamic quality in the entire working speed range including the low-speed high-torque section and the high-speed high-power section.

Beneficial effects: the vibration of the spindle is suppressed through the intelligent control of the pre-tightening force, breaking through the technical problem that the pre-tightening force at the low-speed section of the traditional high-speed machining spindle is too small, while the pre-tightening force at the high-speed section is too large, and it is expected to truly achieve high-speed machining. Four-in-one technological breakthroughs such as chemicalization, high rigidity, high precision, and long life. The pre-tightening force of the electric spindle is intelligently controllable to obtain an electric spindle with excellent dynamic quality in the entire working speed range of low-speed high-torque section and high-speed high-power section.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the intelligent high-speed machining electric spindle with controllable pretightening force of the present invention.

Fig. 2 is a structural principle diagram of the electric control part in Fig. 1 .

Fig. 3 is a structural principle diagram of the actuator part in Fig. 1 .

The above figure includes: main shaft 1, motor 2, rolling bearing 3, encoder 4., single chip microcomputer 5, switching power amplifier 6, proportional pressure valve 7, hydraulic oil station 8, actuator 9, bearing sleeve 9-1, oil chamber 9-2, preload spring 9-3, linear bearing 10.

Detailed ways

The controllable pre-tightening force intelligent high-speed machining electric spindle of the present invention is composed of the following main components:

Encoder 4 adopts photoelectric encoder: EPC-755A, American ENCODER PRODUCTS company;

Single-chip microcomputer 5 adopts digital controller: Intel single-chip microcomputer (8 bits), 83C51GB, 87C51GB;

The switching power amplifier 6 adopts an A/D converter: ADC0808, National Semiconductor Company of the United States; and a D/A converter: DAC0830 series, National Semiconductor Company of the United States;

Proportional pressure valve 7 is: PV21-6;

The power amplifier adopts devices such as IRF540 and MUR820;

Hydraulic oil station 8 is: Southeast University Hydraulic Component Factory, DNHY-12 type.

The mechanical part includes: main shaft 1, motor 2, rolling bearing 3, actuator 9, linear bearing 10, the electric control part includes: encoder 4, single chip microcomputer 5, switching power amplifier 6, proportional solenoid valve 7, hydraulic oil station 8; motor 2 Installed in the middle of the main shaft 1, the front and rear ends of the main shaft 1 are supported by the rolling bearing 3, the rolling bearing 3 at the rear end of the main shaft 1 is supported on the linear bearing 10, the actuator 9 is located on the rolling bearing 3 at the rear end of the main shaft 1; the encoder 4 is electric The signal input terminal of the control part is located on the side of the front end of the main shaft 1, and the collected signal of the main shaft 1 is sent to the single chip microcomputer 5 for processing. The proportional solenoid valve 7 is the signal output terminal of the electronic control part, and the proportional solenoid valve 7 communicates with the constant pressure oil circuit. Actuators 9 are connected. The output terminal of the encoder 4 of the electric control part is connected to the output of the single-chip microcomputer 5.

The input terminal "p1.1", the output terminal "P1.3" of the single chip microcomputer 5 is connected to the input terminal "Hin, Lin" of the switching power amplifier 6, the output terminal of the switching power amplifier 6 is connected to the proportional solenoid valve 7, and the output terminal of the hydraulic oil station 8 Connect to the input terminal of the proportional solenoid valve 7. The actuator 9 is an oil chamber 9-2 with a pre-tension spring 9-3 inside. The oil chamber 9-2 is connected to the proportional solenoid valve 7 through a pipeline. On the two bearing sleeves 9-1 of the bearing 10.

Claims (2)

1. An intelligent high-speed machining electric spindle with controllable pretightening force, characterized in that the electric spindle is composed of a mechanical part and an electric control part, wherein the mechanical part includes: spindle (1), motor (2), rolling bearing (3) , actuator (9), linear bearing (10), electric control part includes: encoder (4), single-chip microcomputer (5), switching power amplifier (6), proportional solenoid valve (7), hydraulic oil station (8); The motor (2) is installed in the middle of the main shaft (1), the front and rear ends of the main shaft (1) are supported by rolling bearings (3), and the rolling bearings (3) at the rear end of the main shaft (1) are supported on linear bearings (10). The encoder (9) is located on the rolling bearing (3) at the rear end of the main shaft (1); the encoder (4) is the signal input terminal of the electronic control part, located on the side of the front end of the main shaft (1), and sends the collected signal of the main shaft (1) to to the single-chip microcomputer (5) for processing, the proportional solenoid valve (7) is the signal output terminal of the electric control part, and the proportional solenoid valve (7) is connected with the actuator (9) through the constant pressure oil circuit; the actuator (9) is An oil chamber (9-2) with a pre-tension spring (9-3) inside, the oil chamber (9-2) is connected to the proportional solenoid valve (7) through a pipeline, and the two pre-tension springs (9-3) Ends are supported on the two bearing sleeves (9-1) of the linear bearing (10) respectively. 2. The intelligent high-speed machining electric spindle with controllable pretension force according to claim 1, characterized in that the output terminal of the encoder (4) of the electronic control part is connected to the input terminal P1.1 of the single-chip microcomputer (5) , the output terminal P1.3 of the single-chip microcomputer (5) is connected to the input terminal Hin and the input terminal Lin of the switching power amplifier (6), the output terminal of the switching power amplifier (6) is connected to the proportional solenoid valve (7), and the output of the hydraulic oil station (8) The terminal is connected to the input terminal of the proportional solenoid valve (7).

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