CN201218247Y - Emergency protection mechanism of three-stage electrohydraulic servo valve - Google Patents

Abstract

The utility model provides a three-stage electro-hydraulic servo valve emergency protection mechanism comprising a two-position three-way reversal valve, a thrust piston, a push rod and a strong spring; the two-position three-way reversal valve is arranged on a valve block which is used for mounting a three-stage electro-hydraulic servo valve; the thrust piston, the push rod and the strong spring are arranged at the left end cover of the three-stage electro-hydraulic servo valve. The utility model can be used for breakdown protection, can effectively improve the safety of a system, has simple structure, convenient operation, reliable performance and timely protection, can be applied to large-scale equipment which uses the three-stage electro-hydraulic servo valve, such as a multi-freedom degree motion simulator, a vibration test stand, and the like.

Description

Three-stage electro-hydraulic servo valve emergency protection mechanism

(1) Technical field

The utility model relates to the emergency protection technology of a servo valve, in particular to an emergency protection when a three-stage electro-hydraulic servo valve itself fails or a hydraulic servo system controlled by it fails.

(2) Technical background

High-performance equipment such as six-degree-of-freedom motion simulators, vibration test benches, and load loaders usually use a three-stage electro-hydraulic servo valve to control the hydraulic cylinder as the power drive part, and the valve controls the telescopic movement of the hydraulic cylinder to achieve the required functions. When the equipment fails, an emergency protection mechanism is needed to complete the failure protection and keep the equipment in a safe position. However, there is no solution to this problem by using the three-stage electro-hydraulic servo valve itself.

(3) Contents of the invention

The purpose of the utility model is to provide a three-stage electro-hydraulic servo valve emergency protection mechanism which is used for system failure protection and improves system safety.

The purpose of this utility model is achieved in this way: it includes a two-position three-way reversing valve, a thrust piston, a push rod and a strong spring, and the two-position three-way reversing valve is installed on the valve block for installing a three-stage electro-hydraulic servo valve. Above; the thrust piston, ejector rod and strong spring are installed on the left end cover of the three-stage electro-hydraulic servo valve.

The utility model also has some technical characteristics:

1. The two-position three-way reversing valve is connected to the oil supply port of the pilot valve of the three-stage electro-hydraulic servo valve and the back pressure chamber of the thrust piston;

2. The thrust piston and the ejector rod are integrally structured.

The utility model designs an emergency protection mechanism for failure of the three-stage electro-hydraulic servo valve itself or failure of the hydraulic servo system controlled by it, which can realize safety protection when the system fails. The two-position three-way reversing valve is a standard part, easy to purchase, and reliable in performance; the thrust piston, ejector rod and strong spring are installed on the left end cover of the three-stage electro-hydraulic servo valve, with simple structure, small size and reliable working performance. Under normal circumstances, the two-position three-way reversing valve is energized, the servo valve is enabled, and the pressure oil is connected to the oil supply port of the pilot servo valve. At the same time, the back pressure chamber of the thrust piston is connected to the pressure oil, and the thrust piston and the ejector rod are Push away the power stage spool, the position of the power stage spool is not restricted, and the three-stage electro-hydraulic servo valve can work normally. When the servo valve fails or the system is in an emergency situation such as power failure or pressure loss, the two-position three-way reversing valve is powered off, the oil supply port of the pilot servo valve is connected to the oil return port, and the back pressure chamber of the thrust piston is unloaded at the same time. The thrust piston is acted by a strong spring, and through the push rod, the power stage slide valve of the three-stage servo valve is pushed to an appropriate position, which just makes the piston rod of the hydraulic cylinder in the system fall back to a safe position at a certain speed.

The utility model has the advantages of simple structure, convenient realization, reliable performance, timely protection, and can greatly improve the safety of the system. It can be used in many large-scale equipment using three-stage electro-hydraulic servo valves, such as multi-degree-of-freedom motion simulators, vibration test benches, etc.

(4) Description of drawings

Fig. 1 is the hydraulic principle diagram when the emergency protection mechanism of the utility model works normally;

Fig. 2 is a schematic diagram of hydraulic pressure during emergency protection of the utility model.

(5) Specific implementation methods

Below in conjunction with accompanying drawing and specific embodiment, the utility model is further described:

1 and 2, this embodiment includes a two-position three-way reversing valve 1, a thrust piston 9, a push rod 8 and a strong spring 10, and the two-position three-way reversing valve 1 is installed on a three-stage electro-hydraulic servo On the valve block of the valve; the thrust piston 9, the ejector rod 8 and the strong spring 10 are installed on the left end cover 11 of the three-stage electro-hydraulic servo valve.

Combined with Figure 1, the components in Figure 1 of the three-stage electro-hydraulic servo valve are: 1. Two-position three-way reversing valve; 2. The pilot valve of the three-stage electro-hydraulic servo valve; 3. The right end cover of the three-stage electro-hydraulic servo valve ; 4. The right centering spring of the three-stage electro-hydraulic servo valve; 5. The power spool of the three-stage electro-hydraulic servo valve; 6. The valve body of the three-stage electro-hydraulic servo valve; 7. The left side of the three-stage electro-hydraulic servo valve Centering spring; 8. Push rod; 9. Thrust piston (Note: 8 and 9 are integrated); 10. Strong spring; 11. Left end cover of three-stage electro-hydraulic servo valve; 12. Three-stage electro-hydraulic servo valve Bolt; I. Power spool left control chamber; II. Power spool right control chamber; III. Thrust piston back pressure chamber; IV. Thrust piston low pressure chamber.

1. Normal work

Referring to Figure 1, the two-position three-way reversing valve 1 is energized, and the pressure oil enters the back pressure chamber III of the thrust piston and the P port of the pilot valve, and the thrust piston 9 and the ejector rod 8 move to the left until the thrust piston 9 touches the bolt 12. When the power spool 5 is in the neutral position under the action of the left centering spring 7 and the right centering spring 4, the movement of the power spool 5 in a certain range in the left and right directions is not restricted, and the pilot valve 2 can control the power spool 5 to be normal. sports.

2. Emergency protection

In combination with Fig. 2, the two-position three-way reversing valve 1 is powered off. The back pressure chamber III of the thrust piston and the P port of the pilot valve are connected to the oil tank, and the thrust piston 9 and the ejector rod 8 move to the right under the action of the strong spring 10 until the thrust piston 9 touches the step of the left end cover 11, at this time the ejector rod 8 Push the power spool 5 to the right to a proper position, and the movement of the power spool 5 in the left and right directions is restricted; at the same time, the pilot valve 2 has no pressure oil, so it cannot supply pressure oil to the left and right control chambers I and II of the power spool 5 , so that the movement of the power spool 5 cannot be controlled.

The pilot valve 2 cannot control the movement of the power spool 5, and the power spool 5 is pushed to a certain position by the ejector rod 8. This position just makes the piston rod of the hydraulic cylinder in the system return to a safe position at a certain speed, thereby providing emergency protection effect.

Claims (3)

1, a kind of three-level electrohydraulic servo valve emergency protection mechanism is characterized in that it comprises two position three way directional control valve, thrust piston, push rod and brute spring, and two position three way directional control valve is installed in the valve piece that is used to install three-stage electrical fluid servo valve; Thrust piston, push rod and brute spring are installed on the left end cap of three-stage electrical fluid servo valve.

2, three-level electrohydraulic servo valve emergency protection mechanism according to claim 1 is characterized in that described two position three way directional control valve connects the pilot valve oil-feed port and the thrust piston back pressure cavity of three-stage electrical fluid servo valve.

3, three-level electrohydraulic servo valve emergency protection mechanism according to claim 1 and 2 is characterized in that described thrust piston and push rod are structure as a whole.

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