catalogue
1. 1 Application of Horizontal Boring Machine
1.2 main structure and motion form of horizontal boring machine
Main structure 1.2. 1
1.2.2 Motion form
1.2.3 T68 requirements for electrical control circuit of horizontal boring machine
Analysis of electrical control circuit of 1.3 T68 horizontal boring machine
List of electrical components used in electrical control circuit of T68 horizontal boring machine
1.3. 1 working principle of main circuit
1.3.2 working principle of control circuit
A. control of main motor M 1
A. positive and negative rotation
B. Micromotion control
C. high-speed and low-speed selection
D. main motor parking brake
E. variable speed pulse control
B. control of fast moving motor M2
C. Interlocking function of spindle box, workbench and spindle motor feed.
D. control circuit diagram
Explanation of electrical control principle of T68 horizontal boring machine
1. 1 Application of Horizontal Boring Machine
Boring machines are mainly used for finishing holes, which are divided into horizontal boring machines, floor boring machines, coordinate boring machines and diamond boring machines. Horizontal boring machine is widely used. It can be used for drilling, boring, reaming, reaming and machining end faces. After using some accessories, you can also turn cylindrical surfaces and threads, and you can use a milling cutter to mill them. This course design mainly takes T68 horizontal boring machine as an example.
1.2 main structure and motion form of horizontal boring machine
T 68 horizontal boring machine is mainly composed of lathe bed, front column, boring machine frame, rear column, tailstock, lower slide plate, upper slide plate and workbench. Its structure is shown in the following figure.
Main structure 1.2. 1
In the process of boring machine processing, the workpiece is usually fixed on the workbench and processed by the cutter fixed on the boring bar or flat turntable (panel).
1) front column: it is fixedly installed at the right end of the lathe bed, and its vertical guide rail is equipped with a spindle box that can move up and down.
2) Spindle box: it is equipped with spindle components, main motion and feed motion variable speed transmission mechanism and control mechanism.
3) Rear column: it can move horizontally along the guide rail of the lathe bed and adjust its position, and the boring bar bracket on it can move vertically synchronously with the headstock. If necessary, it can be removed from the bed.
4) Working platform: it consists of three layers: lower slide plate, upper slide plate and turntable. The lower slide plate can move longitudinally along the horizontal guide rail on the top surface of the lathe bed, the upper slide plate can move transversely along the guide rail on the top of the lower slide plate, and the rotary table can be indexed around the vertical axis on the annular guide rail of the upper slide plate, so that the element can be adjusted to a certain angular position in the horizontal plane, so that holes and planes equal to or angled with each other can be processed in one installation.
1.2.2 Motion form
The machining movements of horizontal boring machine are:
1) Main movements: the rotation of the spindle and the rotation of the turntable.
2) Feed movement: the spindle moves in and out of the headstock; Radial feed of cutter on turntable; Lifting of headstock, i.e. vertical feed; Transverse and longitudinal feed of the workbench. These feeding movements can be manual or electric.
3) Auxiliary motion: the rotation of the turntable; Quick positioning movement of headstock and worktable. In the feeding movement; Longitudinal displacement of the rear column; Vertical displacement of tailstock.
1.2.3 T68 requirements for electrical control circuit of horizontal boring machine
1) The main motion and feed motion are driven by a two-speed motor, and high and low speeds can be selected;
2) The main motor needs positive and negative rotation and inching control;
3) The main motor should be equipped with a quick and accurate stop connecting rod;
4) The spindle speed change should have a variable speed pulse link;
5) The fast moving motor adopts forward and backward inching control mode;
6) The feed motion and uneven motion of the workbench can only be selected and must be interlocked.
Analysis of electrical control circuit of 1.2 T68 horizontal boring machine
T68 horizontal boring machine has complex motion, and many travel switches are used in the control circuit. They are all installed in corresponding positions on the bed. The main circuit has two motors.
The list of electrical components used in the electrical control circuit of T68 horizontal boring machine is shown in the following table:
1.3. 1 working principle of main circuit
T68 horizontal boring machine main motor M 1 adopts two-speed motor. Contactors KM3, KM4 and KM5 perform triangle-binary transformation to obtain the low speed and high speed of the main motor M 1. The main contacts of contactors KM 1 and KM2 control the forward and reverse rotation of the main motor M 1. Electromagnet YB is used for braking when the main motor M 1 is cut off. The forward rotation and reverse rotation of the fast moving motor M2 are controlled by contactors KM6 and KM7. Due to the short working hours of M2, it does not provide overload protection.
The following figure is the main circuit diagram of the electrical control circuit of T68 boring machine:
1.3.2 working principle of control circuit
A. control of main motor M 1
The control of spindle motor M 1 includes high-speed and low-speed motion, forward and reverse rotation, inching control and variable-speed pulse.
A. positive and negative rotation
The main contacts of contactor KM 1 and KM2 complete the change of power phase sequence, thus changing the direction of the motor. Press the start button SB2 for forward rotation, and the contactor KM 1 coil (1-91-kloc-0/3-15-17-19-2/kloc In addition, the constant contact KM 1(3 1-33) is closed to prepare for the high-speed or low-speed operation of the main motor. The main contact of KM 1 in the main circuit is closed, the power supply is connected to the stator winding through KM3 or KM4 and KM5, and the main motor is M 1.
Turn forward.
When reversing, press forward and reverse start button SB5, the corresponding contactor KM2 coil (1-9-11-kloc-0/3-15-25-27-29-6-2) is energized, and the spindle motor M. In order to prevent contactors KM 1 and KM2 from being energized at the same time, the two contactors are interlocked.
B. Micromotion control
The knife is controlled by pointing and cannot be self-locked. When the forward inching button SB3 is pressed, the normally open contact SB3( 15- 17) connects the coil circuit of the contactor KM 1; The normally closed contact SB3( 15-23) disconnects the self-locking circuit of the contactor KM 1, making it unable to self-lock and realizing inching control from the surface.
The reverse inching button SB4 also has a pair of normally open contacts, and this composite button is used to realize inching control conveniently.
C. high-speed and low-speed selection
The spindle motor M 1 is a two-speed motor, and the motor rotates at a low speed when the stator winding is triangular (KM3 is energized and pulled in). The motor rotates at high speed in a double connection mode (KM4 and KM5 are electrically attracted). The selection and conversion of high and low speed are controlled by shift handle and travel switch SQ 1.
Select the spindle speed, put the speed change handle at the corresponding low speed position, and then press the speed change handle. The travel switch SQ 1 is not pressed, and the contact of SQ 1 does not move. Because the main motor M 1 has selected forward rotation or reverse rotation, that is, KM 1 (3 1-33) or km2 (36543). At this time, the contactor KM3 coil (1-9-1-31-33-37-3935-41-6-2) is energized, and its interlocking contact KM3(43-45) is disconnected, thus realizing the contactor. The main contact of KM3 in the main circuit is closed. On the one hand, the electromagnetic brake coil YB is turned on, and the mechanical brake device is released. On the other hand, the stator winding of the spindle motor M 1 is connected with the power supply in a triangle, and the electric surface runs at a low speed.
When the spindle motor is running at high speed, in order to reduce the starting current and mechanical impact, the stator winding is connected to a low-speed connection (triangle connection) at the time of starting, that is, low-speed full-voltage starting, and then it is switched to high-speed operation after a proper delay. Its working state is to put the speed-changing handle at the corresponding high-speed position, then press the handle, the travel switch SQ 1 is pressed, its normally closed contact SQ 1(33-35) is off, its normally open contact SQ 1(33-37) is closed, and the time relay KT coil (/kloc-) is closed. However, the instantaneous contact KT(39-35) of KT immediately closes the delay contact KT(37-43), the contactor KM4 and KM5 coils (1-9-1-33-37-43-45-6-2) are energized, and the main circuit KM is switched on.
D. main motor parking brake
When running at high and low speed, press the stop button SB 1, and all the coils of KM 1~KM5 are cut off, and the self-locking is released. The electromagnetic brake coil YB is cut off, the motor shaft cannot rotate freely, and the main motor M 1 stops quickly.
E. variable speed pulse control
Considering that the speed change of this machine tool can make the gears mesh better during operation, the speed change pulse control is adopted now. The spindle speed change and feed speed change of the machine tool are adjusted by their respective speed change hole disk mechanisms. Its working state is that if you want to change the speed during exercise, you don't have to press the stop button, but pull out the speed change handle. At this time, the travel switch SQ is pressed, the contact SQ2 is turned off, and all the coils of contactors KM3, KM4 and KM5 are turned off, regardless of whether the motor M 1 originally works at a low speed (the main contact of contactor KM3 is closed, triangle connection) or at a high speed (the main contact of contactors KM4 and KM5 is closed, double star connection). At this time, you can turn the shift operation panel (perforated panel), select the required speed, and then push the shift handle back to its original position.
If the handle can be pushed back to its original position (i.e. reset), the travel switch SQ2 will be reset and the contact of SQ2 will be closed. Sometimes, whether the travel switch SQ 1 is pressed or not, the main motor M 1 will start at a low speed to facilitate gear meshing. Then switch to the new preset speed. If the handle can't be pushed back due to the top teeth, the handle can be pushed back and forth, and the handle can be pressed by the movement of the handle to release the travel switch SQ2, so that the motor M 1 can be instantly powered on and off, and an impulse force is generated. During the impulse force, the handle can be quickly engaged and pushed upward. At this time, the variable-speed pulse ends, and the spindle motor M 1 rotates at the newly selected speed.
B. control of fast moving motor M2
In the process of machining, the rapid movement of the headstock, workbench or spindle is to pull the quick handle to connect the mechanical transmission chain, and at the same time press the limit switch SQ5 or SQ6 to energize the coils of the contactors KM4 and KM7, so that the fast moving motor M2 rotates forward or backward, dragging the related parts to move quickly.
(1) Turn the snap-action handle to the "forward" position, press SQ6, and its normally open contact SQ6( 1 1-47) is closed, and the KM6 coil passes (1-9-11).
Turn the handle to the middle position, SQ6 is reset, KM6 coil loses power and releases, and M2 stops running.
(2) Turn the snap handle to the "reverse" position, press SQ5, and its normally open contact SQ5(5 1-53) will be closed, and the KM7 coil will pass (1-9-1-51-).
Turn the handle to the middle position, SQ5 is reset, KM7 coil loses power and releases, and M2 stops running.
C. Interlocking function of spindle box, workbench and spindle motor feed.
In order to prevent the workbench, headstock and spindle from feeding at the same time and damaging the machine tool or tool, interlocking measures are taken in the electrical circuit. Interlocking is realized by two related limit switches SQ3 and SQ4.
When the spindle feeds, the handle presses SQ3, and the normally closed contact SQ3(9- 1 1) of SQ3 is disconnected; When the workbench feeds, the handle presses SQ4, and the normally closed contact (9- 1 1) of SQ4 is disconnected. The normally closed contacts of the two limit switches are disconnected, which cuts off the power supply of the whole control circuit and makes M 1 and M2 unable to work.
D. Control circuit diagram (omitted)
FYI