CN105508330A - Electromagnet-driven digital hydraulic servo actuator - Google Patents

Abstract

The invention discloses a digital hydraulic servo actuator driven by an electromagnet. The hydraulic power unit in the present invention is composed of an electromagnet, a piston, a cone valve, a cylinder block and the like. The piston is driven by the movement of the electromagnet to pressurize the hydraulic oil, and the hydraulic oil is pressed out to provide power for the actuator. There is a two-way hydraulic lock on the oil circuit of the actuator to ensure that the actuator will not suddenly lose control due to power failure and other reasons during the working process. The accumulator on the oil circuit of the mechanism stores energy during the push stroke and releases it during the return stroke to realize the quick return movement of the actuator. The servo control unit includes a displacement sensor installed on the actuator to feed back the speed and displacement of the actuator to the control system, and the control system sends corresponding control signals to realize digital servo control. The invention adopts an integrated hydraulic power unit as a power source, has small volume, large thrust, has explosion-proof performance after being sealed, is easy to realize digital servo control and can control the cost at a low level.

Description

Solenoid driven digital hydraulic servo actuator

technical field

The invention relates to a digital hydraulic servo actuator driven by an electromagnet (hereinafter referred to as the actuator). More precisely, it involves an integrated, high-precision electro-hydraulic servo actuator consisting of three modules: a hydraulic power unit driven by an electromagnet, a hydraulic execution system, and a servo control unit.

Background technique

Actuator refers to a type of mechanism that uses liquid, gas, electricity or other energy to convert energy into drive through a certain mechanical device. A hydraulic actuator is a device that uses high-pressure hydraulic oil to drive the movement of the actuator. Compared with other actuators, it has the advantages of small inertia, fast response, huge force, and stable operation. However, the existing hydraulic actuators use an independent hydraulic pump as the power source and mostly use integrated operational amplifier control, resulting in disadvantages such as poor stability, low control accuracy, large volume, poor anti-interference performance, and high cost.

With the continuous development of industrial technology, the requirements for the control accuracy, intelligence level and system stability of actuators are also increasing. Nowadays, high-end actuators are generally required to have the characteristics of high reliability, high protection, high explosion-proof grade, high intelligence, small size, light weight, etc., but traditional hydraulic actuators are difficult to meet the above requirements at the same time.

Contents of the invention

The invention proposes a digital hydraulic servo actuator based on electromagnet drive. Its basic principle is to use the hydraulic power unit driven by electromagnets (including proportional electromagnets and switch electromagnets) to provide power for a set of integrated hydraulic servo actuators, making it a high-precision, integrated, small-volume, low-cost An electro-hydraulic servo actuator with low cost and other advantages.

In order to realize the above-mentioned functional requirements, the present invention takes the following technical solutions:

The invention includes modules such as a hydraulic power unit driven by an electromagnet, a control oil circuit, an executive hydraulic cylinder, an electromagnetic reversing valve, a two-way hydraulic lock, an accumulator, a displacement sensor, a servo controller, and a power amplification unit.

As the power source of the actuator, the electromagnet-driven hydraulic power unit includes a proportional electromagnet-driven micro-hydraulic pump and multiple micro-hydraulic pumps driven by switch electromagnets.

The mechanical structure of the hydraulic power unit includes hydraulic pump body, electromagnet (including proportional electromagnet and switch electromagnet), moving plunger, one-way poppet valve, inlet (outlet) oil port and other components.

The output displacement of the micro hydraulic pump driven by the proportional electromagnet is precisely and controllable, and can be used for volumetric speed regulation. And the output displacement of the micro hydraulic pump driven by the switch electromagnet is fixed.

The hydraulic cylinder, control oil circuit, electromagnetic reversing valve, two-way hydraulic lock and accumulator constitute the hydraulic execution unit.

A displacement sensor, a servo controller, and a power amplification unit constitute a servo control unit.

The two-way hydraulic lock is composed of two hydraulically controlled one-way valves, which are respectively arranged on the oil inlet oil circuit and the oil return oil circuit of the hydraulic cylinder, and the hydraulically controlled one-way valves on each oil circuit are controlled by the other oil circuit. oil pressure.

Both the electromagnet-driven hydraulic power unit and the electromagnetic reversing valve are controlled by the servo controller, so as to realize the servo control of the motion state of the entire actuator.

It works as follows:

In the hydraulic power unit, the electromagnet generates periodic reciprocating motion after being energized, and the electromagnet drives the plunger to reciprocate, so that the volume of the pump chamber changes periodically. When the electromagnet is stretched, the pump cavity is compressed, the oil pressure increases, the one-way poppet valve at the oil outlet is pressured to open, and at the same time, the one-way poppet valve at the oil inlet is closed under pressure. At this time, the hydraulic oil is compressed from the pump cavity. out. Conversely, when the electromagnet shrinks, the hydraulic oil in the oil tank is sucked into the pump chamber. Such a cycle is repeated, making it a tiny hydraulic pump that provides power for the system.

The high-pressure oil output by the hydraulic power unit enters the hydraulic cylinder along the oil inlet path, and pushes the piston rod to move. The valve opens to allow low pressure oil in the chamber at the other end of the cylinder to flow back to the tank and the actuator moves to one end. When the reversing valve is controlled to be reversed, the hydraulic oil movement direction is reversed, and the actuator moves in the opposite direction, and during the return process, the accumulator releases energy to realize the rapid return movement. When the reversing valve is in the middle cut-off position, the two-way hydraulic lock locks the oil circuit, and the actuator keeps the position unchanged.

In the control unit, the sensor collects the motion state signal (speed, displacement, etc.) of the piston rod in the hydraulic cylinder and feeds it back to the servo control system. The control system adjusts the hydraulic power unit according to the deviation between the actual motion state of the hydraulic cylinder and the expected motion state. The proportional electromagnet in the motor makes corresponding movements to achieve the control goal.

Beneficial effects of the present invention:

1. The present invention adopts the electromagnet-driven hydraulic power unit as the power source, the volume is greatly reduced, it is easy to carry and install, and it has an explosion-proof function after packaging.

2. The total displacement of the hydraulic power unit is flexible and adjustable, and is controlled by the servo control system, so that the output displacement is precisely controllable, so that the movement speed and displacement of the actuator can be precisely controlled.

3. The output of the electromagnet is hydraulically converted, which can achieve a large output force as required.

4. The present invention uses a hydraulic power unit driven by a proportional electromagnet as the power source of the actuator, which is easier to realize digital control than the traditional power source.

5. While realizing the above functions, the cost of this actuator is much lower than similar actuators, and it can realize large output and digital servo control at low cost.

Description of drawings

Figure 1 is the overall schematic diagram of the actuator.

Fig. 2 is a sectional view of the power source of the actuator, that is, the hydraulic power unit driven by the electromagnet.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the electromagnet-driven digital hydraulic servo actuator mainly includes electromagnet-driven hydraulic power unit 1, electromagnetic reversing valve 2, two-way hydraulic lock 3, executive hydraulic cylinder 4, displacement sensor 5, and power amplifier 6 , control system 7, accumulator 8, electronically controlled two-position two-way valve 9 and other components.

As shown in Figure 2, the hydraulic power unit driven by the electromagnet consists of a plunger 11, an electromagnet 12, a unit pump body 13, an oil inlet 14, a passive one-way cone valve 15 at the oil inlet, an oil outlet 17, and an oil outlet It is composed of a one-way movable cone valve 16 and the like.

The actuator is powered by a hydraulic power unit 1 driven by an integrated electromagnet, and the hydraulic power unit is integrated with a small hydraulic pump. In the illustration, the hydraulic power unit is integrated by a small pump A driven by a proportional solenoid and small pumps B, C, and D driven by a switch solenoid. During the propulsion process of the actuator, the hydraulic pump pumps oil outward, the electric control valve 9 is in the lower position, the accumulator stores energy, the reversing valve 2 moves to the right, and the pumped hydraulic oil passes through the left oil circuit and the left side of the reversing valve 2. The side hydraulic control check valve enters the left side of the hydraulic cylinder in the figure, and the hydraulic oil opens the right hydraulic control check valve at the same time. Perform hydraulic oil return to the right side of the hydraulic cylinder.

The hydraulic cylinder piston drives the piston rod to move, and the displacement sensor 5 measures the movement speed and displacement of the piston rod and feeds it back to the digital control system 7 to form a closed-loop feedback. After the signal of the displacement sensor 5 is returned to the digital control system 7, the system judges the next motion state according to the preset program, performs the necessary switching action on the switch type electromagnet, and controls the movement amount of the proportional electromagnetic to control the plunger in the pump. Movement, changing the output displacement, thereby controlling the movement of the actuator, according to the ratio of the piston area S1 in the pump to the piston area S2 of the actuator hydraulic cylinder, the specific value of the flow rate that needs to be adjusted can be determined.

When the digital control system sends a signal to control the reverse movement of the hydraulic cylinder, the reversing valve moves to the left in the figure, the oil inlet direction and the oil output direction of the hydraulic cylinder are interchanged, and the piston moves to the left in the figure.

When the digital control system makes the reversing valve in the middle position, the oil circuit is locked, and the actuator will not move even under external force.

During the return process of the actuator, when the electronically controlled two-position two-way valve 9 is controlled to become the upper channel, the accumulator 8 releases the pressure outward, and the actuator moves at an accelerated speed to realize the rapid return movement. During the process, the electronically controlled two-position two-way valve 9 is in the lower position, and the accumulator 8 stores energy.

Power in this actuator comes from an integrated hydraulic power unit. The hydraulic power unit includes a micro-hydraulic pump A driven by a proportional electromagnet and multiple micro-hydraulic pumps B, C, D, etc. driven by a switch electromagnet. Only one tiny hydraulic pump driven by a proportional electromagnet is used to precisely control the displacement of hydraulic oil. Adopting this combination method can realize precise control of the motion state of the actuator, and at the same time reduce the control cost of the system. The present invention is illustrated by taking 4 miniature hydraulic pumps as an example, among which 3 are switch electromagnet types (B, C, D in Fig. 1), and their displacement is q . 1 proportional solenoid type (A in Figure 1), the displacement can be accurately controlled between 0- q . Then the total displacement of the hydraulic power unit is precisely controllable between 0-4 q . If a displacement output of 3.25 q is required, the controller is required to make all three switch solenoids open, and at the same time control the proportional solenoid type to output a displacement of 0.25 q , then the system realizes a flow output of 3.25 q .

As an optimization, adding a two-way hydraulic lock on the oil can ensure that the position of the actuator is maintained when the actuator is not moving, and it will not slip even if the power is cut off during the process of lifting heavy objects, which enhances the reliability of the actuator.

Preferably, the actuator is packaged in a high-strength aluminum alloy shell to ensure that the internal structure is protected, has explosion-proof performance, and is lighter than the cast steel shell.

A single electromagnet-driven miniature pump includes an oil inlet 14, an oil outlet 17, and is equipped with two passive one-way poppet valves. The electromagnet 12 is linked with the plunger 11, and a closed chamber is formed between the plunger 11 and the pump body. When the electromagnet controls the plunger to move upward, the volume of the closed cavity decreases and the oil pressure rises. At this time, the cone valve 15 of the oil inlet is closed under pressure, and the one-way cone valve 16 of the oil outlet is opened under pressure. Oil is pressed out from the oil outlet 17 to form power. When the control system controls the output rod of the proportional electromagnet 12 to move downward, the plunger 11 is driven to move downward, and the volume of the sealed chamber becomes larger, forming a negative pressure. At this time, the one-way poppet valve 16 of the oil outlet is closed under pressure, and the one-way poppet valve 15 of the oil inlet is opened under pressure, and the hydraulic oil flows back into the chamber to prepare for the next pressure oil, and so on and on.

To sum up, the power source in the present invention integrates the power unit driven by the proportional electromagnet and the power unit driven by the switch electromagnet at the same time, realizing large output and accurate control of displacement while maintaining low cost.

The switching electromagnet and the proportional electromagnet in the present invention realize digital control at the same time, thereby realizing precise servo control on the actuator.

The power source of the electromagnet in the present invention can realize a large output force through hydraulic conversion.

The actuator in the present invention is encapsulated by aluminum alloy, and after the encapsulation is completed, the volume is small and has explosion-proof performance.

The two-way hydraulic lock in the present invention can ensure that the actuator is stable in the working process, and will not reverse movement or run out of control due to problems such as power failure.

The technical solution of the present invention is not limited to the limitations of the above-mentioned specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the scope of protection of the present invention.

Claims (1)

1. the digital hydraulic servo final controlling element of solenoid actuated, primarily of hydraulic power unit, electrically-controlled valve, execution oil hydraulic cylinder, accumulator, bidirectional hydraulic lock, displacement transducer, power amplifier, numerical control system, is characterized in that:

Described hydraulic power unit oil outlet is connected with electrically-controlled valve, filler opening is connected with fuel tank, electro hydraulic valve is connected with bidirectional hydraulic lock, and bidirectional hydraulic lock is connected with oil outlet with execution hydraulic cylinder oil inlet, and displacement transducer is fixed on and performs on oil hydraulic cylinder; Accumulator is connected by the fuel-displaced oil circuit of described electrically-controlled valve and hydraulic power unit;

Described hydraulic power unit, electrically-controlled valve all accept numerical control system and send via the control of power amplifier amplifying signal, and displacement transducer is by signal feed back to numerical control system, and whole final controlling element realizes closed loop control;

Described hydraulic power unit comprises an oil hydraulic pump based on proportion electro-magnet driving and multiple oil hydraulic pump driven based on switch electromagnet, and each oil hydraulic pump comprises electromagnet, cylinder body, piston, filler opening, oil outlet, filler opening mitre velve, oil outlet mitre velve;

Electromagnet is connected with piston, and cylinder body is divided into upper and lower two spaces by piston, and upper chamber is connected with oil outlet with filler opening respectively, and filler opening and oil outlet are respectively arranged with filler opening mitre velve, oil outlet mitre velve;

Described bidirectional hydraulic lock comprises two Pilot operated check valves, is arranged in fuel-displaced oil circuit and oil return circuit respectively, one-way passage when Pilot operated check valve oil circuit control does not have pressure, ensure final controlling element rise and fall weight time can not drop.