1 electrical control panel
As shown in Figure 4- 18, the electric control panel has the following functions:
Figure 4- 18 Electrical Control Panel
1 7 output Ⅱ jack; 2, 6 —— Output two indicator lights; 3,21-output I indicator light; 4.20— output I jack; 5— Power input interface (DC24V); 8- control group 2; 9, 17— normally open start; 10, 18- normally closed stop; 1 1, 14— commutation Ⅱ; 12, 15— commutation Ⅰ; 13, 16— Stop; 19- control group 1
(1) rated voltage: 220V；; Rated current: 7a; Frequency: 50Hz.
(2) The oil pump motor has interlocking function with commutation Ⅰ and Ⅱ, that is, when the oil pump motor is not started, the control circuits of commutation Ⅰ and Ⅱ cannot work.
(3) Pay attention to the fact that when starting the oil pump motor, first turn the speed regulating knob of the motor governor counterclockwise to the slowest position, then start the button, and then turn the governor knob clockwise to the speed or working pressure required by the oil circuit.
(4) The electric control circuit of the reversing valve has three working states: stop, reversing Ⅰ and reversing Ⅱ, which can control both the three-position four-way solenoid valve and the two-position four-way solenoid valve.
(5) During commutation, the "small three-wire" socket outputs one of two groups of 220V voltages to control the electromagnet.
(6) When the 2-position 4-way (2-position 2-way) solenoid valve is controlled, the commutation I-state electromagnet is powered off or the commutation II-state electromagnet is powered off and does not work.
(7) The reversing I state can be directly controlled by the button, or automatically controlled from the outside by a normally closed stop jack (normally open start jack) with a travel switch and a pressure relay.
(8) The normally open starting jack requires the normally open contact to be connected with the jack. The normally open contact is closed once, and the "small three-wire" socket commutates to Group I to output 220V voltage, and the line has self-locking function. The normally closed stop jack requires that the normally closed contact be connected with the jack. When the normally closed contact is opened once, the "small three-wire" socket has no voltage output.
(9) The operation and function of commutation ⅰ and commutation ⅱ control circuits are exactly the same.
2 oil pump motor and speed regulating circuit
Because each oil circuit of the test-bed has the characteristics of large loop pressure range and inconsistent flow requirements, the oil pump motor adopts small DC motor and its governor. The oil pump motor governor is shown in Figure 4- 19. This DC motor governor adopts patented technology, which can directly convert 220-volt alternating current into a set of 220-volt fixed excitation DC power supply and a set of 0-220-volt adjustable armature DC power supply for DC motors. It has the advantages of small volume, wide speed range, good overload protection performance and convenient use.
Technical parameters of DC motor: motor model Z400-200；; ; The rated current is 2.5A；; Rated power 400W；; Rated voltage DC 220 volts; The speed range is 0 ~ 4000 rpm.
3 Hydraulic pump and hydraulic motor
In hydraulic system, hydraulic pump and hydraulic motor (motor) are both energy conversion elements. Hydraulic pump is a power element that converts mechanical energy into liquid pressure energy. Hydraulic motor is the reverse device of hydraulic pump, which converts the pressure energy of liquid into mechanical energy and outputs motion, and is the executive element. Hydraulic pump and hydraulic motor used in hydraulic system are both positive displacement, and their working principle is to generate pressure energy (hydraulic pump) or output mechanical energy (hydraulic motor) by using the change of sealing volume.
Gear pump is a commonly used hydraulic pump, which has two structural modes: external meshing and internal meshing. It has the advantages of simple structure, convenient manufacture, low price, reliable work, good self-absorption, and insensitivity to oil pollution. The disadvantage is that the flow and pressure pulsation is large and the noise is also large.
The gear oil pump is shown in Figure 4-20, and the structure refers to the domestic CB- 10 gear oil pump. The upper shell and gear are made of imported transparent plexiglass, the transmission shaft is made of 45 # medium carbon steel, and the sliding bearing is made of brass. It has the advantages of transparency, intuition and vivid image, and can be used as a teaching model or experimental component. When running the gear oil pump at low speed, you can observe the process of oil absorption, gear rotation with oil, meshing and oil discharge, and intuitively understand the working principle.
4 hydraulic cylinder
Hydraulic cylinder is an executive element in hydraulic system, and it is an energy conversion device that converts the pressure energy of liquid into mechanical energy, which is used to drive the working mechanism to realize linear reciprocating motion or reciprocating swing. The hydraulic cylinder is simple in structure and reliable in operation. It has been widely used in the hydraulic system because it omits the deceleration mechanism, has no transmission gap, has stable transmission and fast response when doing linear reciprocating motion.
Figure 4- 19 oil pump motor governor
1- oil drain switch; 2- factory number; Three speed control knob
Figure 4-20 Gear Oil Pump
1-N hole (oil drain); 2-hexagon socket head bolt; 3m hole (oil suction hole); 4- transmission shaft; 5 gears; 6 stitches
As shown in figure 4-2 1, it is a double-acting cylinder. Among them, the cylinder body, end cover, stroke bump and bump bracket are made of imported transparent plexiglass material, and the ejector pin is made of 45 medium carbon steel, which is assembled with standard parts such as oil joint, sealing ring and hexagon socket bolt, which is transparent and clear. Through it, we can clearly observe the structure and working process of piston, ejector rod, oil seal, oil hole and spring. It is vivid and reliable, and can be used as a teaching model or a hydraulic experimental component for experimental demonstration.
Fig. 4-2 1 double-acting cylinder
1- a hole; 2- piston; 3-b hole; 4— Rear end cover; 5— Cylinder block; 6— Front end cover; 7- ejector pin
5 Hydraulic control valve
In the hydraulic system, the hydraulic control valve (hydraulic valve for short) is used to control the pressure, flow and flow direction of oil, so as to control the start, stop, movement direction, speed and acting force of the hydraulic actuator and meet the requirements of hydraulic equipment for various working conditions. There are many kinds of hydraulic valves with different functions, which are an important part of the hydraulic system.
1) Classification of hydraulic valves
Hydraulic valves can be divided into directional control valves (such as one-way valves and directional valves). ), pressure control valve (such as relief valve, pressure reducing valve, sequence valve, etc. ) and flow control valves (such as throttle valves, speed control valves, etc. ) depending on the purpose. These three types of valves can cooperate with each other to form a compound valve, so as to reduce pipeline connection and make the structure compact, such as one-way sequential valve.
Hydraulic valves can be divided into manual type, motor type, electric type, hydraulic type and electro-hydraulic type according to different working modes.
According to different control methods, hydraulic valves can be divided into fixed value or on-off control valves, electro-hydraulic proportional control valves, electro-hydraulic servo control valves and digital valves.
Hydraulic valves are divided into tubular (threaded) connecting valves, plate connecting valves, superimposed connecting valves and cartridge valves according to different installation methods.
2) Requirements for hydraulic valves
The basic requirements of hydraulic transmission system for hydraulic valves are:
(1) is sensitive in action, reliable in work, and less in impact and vibration during work;
(2) the pressure loss is small when the oil passes through;
(3) Good sealing performance, less internal leakage and no external leakage;
(4) Compact structure, convenient installation, debugging and maintenance, and good versatility.
3) directional control valve
The function of directional control valve is to control the direction of liquid flow in hydraulic system. The working principle of directional control valve is to use the change of relative position between valve core and valve body to realize the connection or disconnection between oil circuits, so as to meet the requirements of the system for the direction of oil circuits.
Figure 4-22 shows a one-way valve, and Figure 4-23 shows a three-position five-way manual reversing valve.
Figure 4-22 Check Valve
1- spool; 2— Valve plug; 3- spring; 4-P2 hole (oil outlet); 5— Valve body; 6-P 1 hole (oil inlet)
Figure 4-23 Three-position five-way manual reversing valve
1- handle; 2- a hole; 3-b hole; 4- valve core; 5- spring; 6— Rear end cover; 7— Spring seat; 8—O2 hole (oil return hole); 9-P hole (oil inlet hole); 10-o1hole (oil return hole); 11-cover; 12 needle
4) Pressure control valve
In the hydraulic system, the valves that control the liquid pressure are collectively called pressure control valves. It has the same feature that it works by using the principle of balance between liquid pressure and spring force acting on the valve core. Commonly used pressure control valves include safety valve, pressure reducing valve, sequence valve and pressure relay.
Figure 4-24 shows the safety valve, and Figure 4-25 shows the sequence valve.
5) Flow control valve
The flow control valve changes the hydraulic resistance by changing the size of the control port, so as to adjust the flow through the valve port and change the movement speed of the actuator. There are many kinds of flow control valves, such as throttle valve, speed regulating valve, overflow throttle valve and diverter valve. Among them, the throttle valve is the most basic flow control valve. Figure 4-26 shows the speed regulating valve and Figure 4-27 shows the throttle valve.
6 Auxiliary device of hydraulic system
The auxiliary devices of hydraulic system include accumulator, oil filter, oil tank, heat exchanger, seal, pipe fitting, travel switch, pressure gauge, tee, etc. Figure 4-28 shows the oil tank, figure 4-29 shows the tee, figure 4-30 shows the travel switch, and figure 4-3 1 shows the pressure gauge.
Figure 4-24 Overflow Valve
1- adjusting nut; 2- adjusting lever; 3- valve cover; 4-O hole (oil inlet hole); 5— Rear cover; 6- valve core; 7-P hole (oil return hole); 8-spring; 9— Lock nut
Figure 4-25 Sequence Valve
1- valve cover; 2- adjusting nut; 3- adjusting lever; 4— Lock nut; 5-P2 hole (oil outlet); 6- valve core; 7— Rear cover; 8—P 1 hole (oil inlet hole); 9-L hole (oil drain hole)
Figure 4-26 Speed Control Valve
1- adjusting handle, 2- spring; 3-P3 hole (oil outlet); 4-p1hole (oil inlet hole)
Figure 4-27 Throttle valve
1—P2 hole (oil outlet); 2— Valve body; 3- spring; 4-p1hole (oil inlet hole)
Figure 4-28 Oil Tank
1-oil suction hole; 2-nut oil; 3— Oil return hole; 4-Install the side strip; 5- isolation plate; 6- Oil filter
Figure 4-29 tee
Figure 4-30 Travel switch
1-the stroke is concave and convex; 2- microswitch; 3- signal line; 4— Travel fixing block; 5- signal line; 6— Microswitch
Figure 4-3 1 pressure gauge
1- pressure gauge; 2- Install the base; 3- oil connector