1 Introduction
Mechatronics technology is a comprehensive technology that organically combines various technologies such as mechanical technology, electrical and electronic technology, microelectronic technology, information technology, sensor technology, interface technology, and signal conversion technology, and comprehensively applies them to practice. Modern automatic production equipment can almost be said to be mechatronics equipment.
The rapid development of mechatronics technology has promoted the continuous progress of social industrial technology, and its application in the railway industry has become more and more extensive. Whether it is a high-speed EMU in the wheel-rail transportation system, a quasi-high-speed large railway vehicle, a heavy-duty train responsible for freight, or a trackless maglev train, as well as the operating environment foundation of the entire train, a large number of mechatronics designs are involved.
The degree of mechanical and electrical integration in the railway industry has been continuously improved, which has greatly simplified the mechanical structure, more reasonable layout and better performance. In the modern railway industry, the complexity of many mechanical designs is gradually transferred to the electromechanical control design, the electromechanical is fully coupled, and the multidisciplinary knowledge is crossed. The "intelligent" action is continuously implanted in the railway industry, so that the railway design technology is constantly innovated and the design is constantly improved.
2 Overview of the switch machine
The switch machine is the actuator of the switch control system. It is used to switch the switch point rail or core rail, and it means the position and state of the switch point rail or core rail in the supervision interlocking area.
2.1 The role of the switch machine
Generally speaking, the function of the switch machine has the following four aspects:
(1) Convert the position of the switch. Convert to in-position or inversion as required.
(2) After the switch is converted to the required position and is closely attached, it can be locked to prevent external force from converting the switch.
(3) Correctly reflect the actual position of the turnout. After the point rail of the turnout is closely attached to the basic rail, the corresponding representation is given.
(4) When the turnout is squeezed or is in the "four-open" position for some reason, an alarm and indication are given in time.
2.2 Classification of switch machines
(1) According to the action energy and transmission mode: electric pan, electric hydraulic zY, electric idle switch machine ZR.
(2) According to the type of power supply, it can be divided into DC and AC.
(3) Action speed: ordinary action (above 3.8 s. Most of them belong to this category) and fast action (below 0.8 s, generally used in hump shunting yard).
(4) According to the way of locking the switch, it is divided into internal locking and external locking: Internal locking: relying on the locking device inside the switch machine to lock the tip rail of the switch, which is an indirect locking method. outside
Locking: rely on the external locking device to directly stick the basic rail and the tip rail, and lock the repelling rail in a fixed position. Direct locking method. Reliable locking. The train has almost no impact on the switch machine.
(5) According to whether it is squeezed, it can be divided into squeezed and non-squeezable switch machines: Extrudable type: equipped with a switch protection (squeeze or squeeze) device. When the switch is squeezed, the action lever is unlocked to protect the entire switch. machine. Non-extrudable type: When the turnout is squeezed, the connection structure between the action rod and the whole machine is broken, and the whole machine should be replaced.
2.3 The basic points of the switch machine
In order to maintain the smooth operation of the railway line, the following four basic requirements are required for the switch machine:
(1) Sufficient pulling force to drive the tip rail to move back and forth in a straight line; when the tip rail is blocked and cannot move to the end, the tip rail should be restored to its original position by manipulation at any time.
(2) As a locking device, when the tip rail is not closely attached to the basic rail, it should not be locked. Once locked, it should be ensured that the turnout will not be incorrectly unlocked due to the vibration of the train passing through.
(3) As a monitoring device. The status of the turnout should be correctly reflected.
(4) After the turnout is squeezed, the turnout should not be converted until it is repaired.
3 Analysis of the working process of the electro-hydraulic switch machine
With the development of the railway industry, the speed-increasing turnout has higher and higher requirements on the action efficiency and stability of the switch machine. The electro-hydraulic switch machine has occupied half of the switch machine market in my country due to its fast action speed and reliable performance.
The electro-hydraulic switch machine is a switch device that uses electric motor drive and hydraulic transmission to convert switches. The hydraulic switch machine cancels the gear transmission and the reducer, and simplifies the mechanical structure. Minimize mechanical wear. Reduced maintenance effort. And it is suitable for speed-up turnout. However, hydraulic transmission has high requirements on hydraulic medium, high requirements on components, and low transmission efficiency.
Hydraulic transmission uses liquid as the working medium to transmit energy. Hydraulic transmission is a type of hydraulic transmission. It uses the pressure of oil to transfer energy.
3.1 The principle of hydraulic transmission of the switch machine
Hydraulic transmission transmits energy and power by means of the pressure of the liquid in a closed container. Although liquids do not have a three-dimensional aggregate shape. But there are almost unchanged containers. when it is contained in a closed system. The pressure can be transferred from one place to another. When high-pressure liquid flows in pipes and cylinders. It can transmit mechanical energy. Any hydraulic transmission is based on the transmission of mechanical energy through the flow of pressurized liquid in a closed container.
3.2 Advantages of the switch machine using hydraulic transmission
(1) It is easy to obtain a large force or moment, and it is easy to control. It is easy to use the oil pump to obtain higher pressure (7-35 MPa). The effective pressure bearing area of the oil cylinder is large, and a large force or torque can be obtained.
(2) It is easy to realize linear reciprocating motion, directly push the working mechanism, and is suitable for pulling the displacement of the switch rail.
(3) It is easy to adjust the withering speed ratio. For example, when the throttle valve is used to adjust the speed, if the flow-feed speed change is changed from 0.02L/min to 100L/min, the speed control ratio will reach 5000, which is unmatched by other transmission methods.
(4) Large output power and small size. The size of the oil pump is only 12% to 13% of the same power motor, and the weight is only 10% to 20%.
(5) The transmission is smooth and even.
(6) In reciprocating and rotating motion. Shifting and reversing can often be made quickly and without shock. Due to the light weight and low inertia of the hydraulic mechanism, high-speed response can be obtained. It takes 1 to 2 s to start a medium-power motor, while a liquid JK machine of the same power only needs 0.1 s.
(7) It is easy to obtain various complex actions; it is easy to arrange and manipulate, and multiple traction points can be added as needed; it is easy to prevent overload accidents.
(8) The manipulation force is small.
(9) Automatic lubrication, longer life of components.
(10) It is easy to cooperate with electrical equipment to produce a composite control system with good performance and high degree of automation.
3.3 The basic structure of the electro-hydraulic switch machine.
The electro-hydraulic switch machine is composed of a power system (DC motor or a flow motor), a hydraulic system, an oil circuit system, a conversion locking system and a contact (circuit) system.
3.4 The structure of ZYJ7 electro-hydraulic switch machine
The ZYJ7 switch machine is composed of the main engine and the SH6 type conversion lock (auxiliary machine), which are used for the first traction point and the second traction point respectively. The main engine and the auxiliary machine are connected by oil pipes. zYJ7 switch machine main engine is composed of electric motor, oil pump, oil cylinder, starting oil cylinder, contact system, locking rod, action rod and other parts. SH6 conversion type lock (auxiliary machine) is mainly composed of oil cylinder, extruding contact, indicating rod, action rod and so on.
3.5 Oil circuit and action principle of ZYJ7 electro-hydraulic switch machine
The oil circuit part of ZYJ7 electro-hydraulic switch is shown in Figure 1.
The oil pump is the power source of the entire system and is used to convert mechanical energy into liquid pressure energy. The flow throttle valve, overflow valve, one-way valve, etc. constitute the control device. It is used to adjust and control the flow direction, flow and pressure of hydraulic oil to realize different working cycles. The cylinder is the actuator of the system. It converts hydraulic energy into mechanical energy. Filters, fuel tanks, etc. are auxiliary devices.
