CN114876897A - Piezoelectric and electromagnetic coil composite driven high-frequency digital valve and working method thereof - Google Patents

Abstract

The invention discloses a high-frequency digital valve driven by piezoelectricity and an electromagnetic coil in a composite mode.A sliding valve and a piezoelectric stack are respectively arranged on the left side and the right side of a movable iron core, the piezoelectric stack is used for pushing the movable iron core and driving the sliding valve to move, and the piezoelectric stack is used for instantly pushing the movable iron core to reduce the air gap reluctance at the initial excitation stage of the coil, so that the magnetic flux and the electromagnetic force of a magnetic circuit are improved, and the problem of hysteresis caused by the large inductance of the traditional electromagnetic coil is effectively solved; the working method comprises three working modes which are adjusted in real time according to the actual needs of the controlled object. The high-frequency digital valve structure has the advantages of high frequency response of the piezoelectric stack and large displacement of electromagnetic drive; the working method is beneficial to improving the working efficiency and the control precision of the high-frequency digital valve.

Description

A high-frequency digital valve driven by piezoelectric and electromagnetic coils and its working method

technical field

The invention relates to a high-frequency digital valve driven by piezoelectric and electromagnetic coils and a working method thereof.

Background technique

Traditional electro-hydraulic servo systems are widely used in high-end equipment fields such as aerospace, deep-sea exploration, weaponry and construction machinery by virtue of their high bandwidth and high precision. However, due to the inherent structural constraints of proportional/servo valves, electro-hydraulic servo systems have reliability. Low efficiency, low efficiency and high cost. Compared with the continuous throttling adjustment principle of proportional/servo valve, digital valve only works in fully open or fully closed state, and adjusts the output discrete flow by changing the ratio of opening and closing time. The digital hydraulic system based on digital valve distribution is considered to be a potential solution to replace the traditional electro-hydraulic servo system in the future due to its advantages of strong oil resistance, high work efficiency and low cost.

However, high frequency response and large displacement have always been an important problem restricting the mass application of digital valves. For the digital valve driven by the existing electromagnetic coil, it is difficult to further improve its dynamic performance due to the restriction of the large inductance of a single coil. For digital valves driven by smart materials, the high dynamic advantages of smart materials can significantly increase the frequency response of digital valves to more than 200 Hz. However, due to the constraints of the small output displacement of smart materials, digital valves are difficult to apply to large flow applications.

SUMMARY OF THE INVENTION

The present invention provides a high-frequency digital valve driven by piezoelectric and electromagnetic coils and its working method in order to solve the above-mentioned problems in the prior art. Movement, thereby improving the dynamic performance of opening, and then using electromagnetic drive to maintain a large displacement output.

In order to achieve the above purpose, the present invention provides a high-frequency digital valve driven by piezoelectric and electromagnetic coils, including a hydraulic valve body, a left end cover, a coil housing, a right end cover, a piezoelectric stack housing, a hydraulic plug, a spring, Slide valve, first sealing ring, second sealing ring, static iron core, coil skeleton, coil, moving iron core, guide sleeve, triangular magnetic isolation ring, bolt, adjusting screw, piezoelectric stack, output rod, disc spring , adjustment block, bolts; the hydraulic valve body is provided with a first step, a second step, a third step, a fourth step, a center hole, a first annular groove and a second annular groove; the left end cover is provided with There are a first inner hole, a second inner hole and a third inner hole; the slide valve is provided with a fifth step and a sixth step; the static iron core is provided with a seventh step, an eighth step and a ninth step Steps and Tenth Step.

Further, several P ports are arranged in the axial direction of the first step of the hydraulic valve body, several A ports and a first annular groove are arranged in the axial direction of the second step, and a second annular groove is arranged in the axial direction of the third step. groove; the first sealing ring and the second sealing ring are respectively placed in the first annular groove and the second annular groove of the hydraulic valve body; the hydraulic plug is placed in the hydraulic valve body inside the center hole, and the left step of the hydraulic plug is in interference fit with the center hole of the hydraulic valve body; the spring is sleeved on the right step of the hydraulic plug, and the right side of the spring is in contact with the center hole of the hydraulic valve body; The fifth step of the slide valve is in contact; the slide valve is placed in the center hole of the hydraulic valve body; the fifth step of the slide valve completely covers the P port of the hydraulic valve body, ensuring that the initial state is There is no leakage at the P port; the fourth step of the hydraulic valve body is an interference fit with the first inner hole of the left end cover; the seventh step of the static iron core is a clearance fit with the first inner hole of the left end cover, The eighth step of the static iron core is in an interference fit with the second inner hole of the left end cover.

Further, the coil bobbin is sleeved on the outside of the ninth step of the static iron core; the coil is wound on the coil bobbin; the moving iron core is placed on the right side of the static iron core, and the moving iron core is The left step of the iron core passes through the center hole of the static iron core and contacts with the sixth step of the slide valve; the guide sleeve is sleeved on the tenth step of the static iron core and the moving iron core The outer side of the right step; the triangular magnetic isolation ring is welded on the side of the guide sleeve, and the welding position can surround the gap between the static iron core and the moving iron core, so as to reduce the magnetic leakage of the main air gap; so The outer circular surface of the coil housing is in interference fit with the third inner hole of the left end cover; the right end cover and the coil housing are connected by the bolts.

Further, the piezoelectric stack housing and the right end cover are connected by the bolts; the adjusting screw plug is connected with the right central hole of the piezoelectric stack housing by screws; the piezoelectric stack is placed On the inner side of the piezoelectric stack housing, and the right end face of the piezoelectric stack is in contact with the left end face of the adjusting plug, the axial direction of the spool valve can be changed by adjusting the feed amount of the adjusting plug position; the left end face of the piezoelectric stack is in contact with the right end face of the output rod; the left end face of the output rod is in contact with the right end face of the moving iron core, for the output of the piezoelectric stack Displacement is transmitted to the moving iron core; the adjusting block is connected with the piezoelectric stack shell by screws; the disc spring is placed in the middle of the adjusting block and the output rod, and the adjusting block can be rotated by rotating the adjusting block. Change the compression amount of the disc spring, and then change the pre-pressure of the piezoelectric stack; the adjustment screw is connected to the piezoelectric stack, the output rod, the disc spring, the adjustment block, the The moving iron core and the sliding valve are on the same axis to ensure that all moving parts will not be stuck.

The invention also discloses the working method of the high-frequency digital valve, which is divided into the following three modes:

Mode 1, namely high frequency small displacement output mode;

At this time, only the piezoelectric stack works, and the piezoelectric stack pushes the moving iron core to move under the voltage excitation, which in turn drives the spool valve to reciprocate. Due to the high-frequency response and small displacement characteristics of the piezoelectric stack, the high-frequency digital valve The output flow is small, but the resolution is high, so this mode is suitable for low-speed and high-precision conditions;

Mode 2, that is, the low-frequency large-displacement output mode;

At this time, only the moving iron core works, and the coil is electrified, causing the moving iron core and the static iron core to be magnetized, which further makes the moving iron core move under the action of the magnetic field force, and drives the spool valve to reciprocate. The dynamic characteristics result in a large output flow of the high-frequency digital valve, but the accuracy is poor, so this mode is suitable for high-speed and low-precision conditions;

Mode 3, that is, high-frequency large-displacement output mode;

At this time, both the piezoelectric stack and the moving iron core are working. In the initial excitation stage of the coil, the piezoelectric stack is energized to work, pushing the moving iron core to move, resulting in the reduction of the magnetic resistance of the magnetic circuit (the working air gap is reduced), which further improves the The magnetic flux of the magnetic circuit is increased; the piezoelectric stack returns to its original position after continuous operation for 1ms, and switches to the electromagnetic drive mode. Due to the instantaneous increase of the magnetic flux of the magnetic circuit, the electromagnetic force increases rapidly, and the opening dynamic performance is significantly improved. The high-frequency digital valve can maintain a large displacement output, and finally the high-frequency digital valve can output a large displacement while obtaining a high-frequency response, so this mode is suitable for high-speed and high-precision conditions.

Compared with the prior art, the present invention has the following beneficial effects: (1) In the initial excitation stage of the coil, the piezoelectric stack is used to instantaneously push the moving iron core to move to reduce the reluctance, thereby increasing the magnetic flux of the magnetic circuit, and finally improving the opening of the coil. The structure has both the high-frequency response of the piezoelectric stack and the large displacement advantages of the electromagnetic drive; (2) the proposed high-frequency digital valve working method can adjust the working mode in real time according to the actual needs of the controlled object. The high-frequency small-displacement output mode, the low-frequency large-displacement output mode, and the high-frequency large-displacement output mode can be switched on demand, which significantly improves work efficiency and control accuracy.

Description of drawings

1 is a two-dimensional cross-sectional view of a high-frequency digital valve driven by piezoelectric and electromagnetic coils in an embodiment of the present invention;

2 is a two-dimensional cross-sectional view of a hydraulic valve body in an embodiment of the present invention;

3 is a two-dimensional cross-sectional view of the left end cap in the embodiment of the present invention;

4 is a two-dimensional cross-sectional view of a slide valve in an embodiment of the present invention;

5 is a two-dimensional cross-sectional view of a static iron core in an embodiment of the present invention;

FIG. 6 is a schematic diagram of a high-frequency large-displacement working method of a high-frequency digital valve in an embodiment of the present invention.

Among them: 1. Hydraulic valve body; 1.1, the first step; 1.2, the second step; 1.3, the third step; 1.4, the fourth step; 1.5, the central hole; 1.6, the first annular groove; 1.7, the second annular Groove; 2. Left end cover; 2.1, First inner hole; 2.2, Second inner hole; 2.3, Third inner hole; 3, Coil shell; 4, Right end cover; 5, Piezoelectric stack shell; 6, Hydraulic Plug; 7, spring; 8, slide valve; 8.1, fifth step; 8.2, sixth step; 9, first sealing ring; 10, second sealing ring; 11, static iron core; 11.1, seventh step; 11.2, the eighth step; 11.3, the ninth step; 11.4, the tenth step; 12, the coil frame; 13, the coil; 14, the moving iron core; 15, the guide sleeve; 16, the triangular magnetic isolation ring; 17, the bolt; 18 , Adjust the screw plug; 19, Piezoelectric stack; 20, Output rod; 21, Disc spring; 22, Adjustment block; 23, Bolt.

Detailed ways

The present invention is further illustrated below in conjunction with the accompanying drawings and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "center", The orientation or positional relationship indicated by "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that A device or element must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

As shown in Figures 1 to 5, the present invention discloses a high-frequency digital valve driven by piezoelectric and electromagnetic coils, comprising a hydraulic valve body 1, a left end cover 2, a coil housing 3, a right end cover 4, and a piezoelectric stack housing 5. Hydraulic plug 6, spring 7, slide valve 8, first sealing ring 9, second sealing ring 10, static iron core 11, coil bobbin 12, coil 13, moving iron core 14, guide sleeve 15, triangular magnetic isolation Ring 16, bolt 17, adjusting screw 18, piezoelectric stack 19, output rod 20, disc spring 21, adjusting block 22, bolt 23; the hydraulic valve body 1 is provided with a first step 1.1 and a second step 1.2 , the third step 1.3, the fourth step 1.4, the central hole 1.5, the first annular groove 1.6 and the second annular groove 1.7; the left end cover 2 is provided with a first inner hole 2.1, a second inner hole 2.2, Three inner holes 2.3; the slide valve 8 is provided with a fifth step 8.1 and a sixth step 8.2; the static iron core 11 is provided with a seventh step 11.1, an eighth step 11.2, a ninth step 11.3 and a tenth step 11.4;

The axial direction of the first step 1.1 of the hydraulic valve body 1 is provided with several P ports, the axial direction of the second step 1.2 is provided with several A ports and the first annular groove 1.6, and the axial direction of the third step 1.2 is provided with a number of A ports. Two annular grooves 1.7; the first sealing ring 9 and the second sealing ring 10 are respectively placed in the first annular groove 1.6 and the second annular groove 1.7 of the hydraulic valve body 1; the hydraulic plug 6 is placed in the central hole 1.5 of the hydraulic valve body 1, and the left step of the hydraulic plug 6 is in an interference fit with the central hole 1.5 of the hydraulic valve body 1; the spring 7 is sheathed in the hydraulic valve body 1. On the right step of the plug 6, the right side of the spring 7 is in contact with the fifth step 8.1 of the slide valve 8; the slide valve 8 is placed in the central hole 1.5 of the hydraulic valve body 1; the The fifth step 8.1 of the spool valve 8 completely covers the P port of the hydraulic valve body 1 to ensure that there is no leakage at the P port in the initial state; the fourth step 1.4 of the hydraulic valve body 1 and the first step of the left end cover 2 The inner hole 2.1 is an interference fit; the seventh step 11.1 of the static iron core 11 is a clearance fit with the first inner hole 2.1 of the left end cover 2, and the eighth step 11.2 of the static iron core 11 is in clearance fit with the left end cover 2. The second inner hole 2.2 is an interference fit.

In this embodiment, the coil bobbin 12 is sleeved on the outer side of the ninth step 11.3 of the static iron core 11; the coil 13 is wound on the coil bobbin 12; the moving iron core 14 is placed on the static iron core 11. On the right side of the iron core 11, the left step of the moving iron core 14 passes through the center hole of the static iron core 11 and contacts the sixth step 8.2 of the slide valve 8; the guide sleeve 15 is sleeved on The tenth step 11.3 of the static iron core 11 and the outer side of the step on the right side of the moving iron core 14; the triangular magnetic isolation ring 16 is welded on the side of the guide sleeve 15, and the welding position can surround the static iron core The gap between 11 and the moving iron core 14 is used to reduce the magnetic flux leakage of the main air gap; the outer circular surface of the coil shell 3, the third inner hole 2.3 of the left end cover 2 is an interference fit; the right end cover 4 It is connected with the coil housing 3 by the bolts 17 .

In this embodiment, the piezoelectric stack housing 5 and the right end cover 4 are connected by the bolts 23 ; the adjusting screw plug 18 is connected with the right central hole of the piezoelectric stack housing 5 by screws ; The piezoelectric stack 19 is placed inside the piezoelectric stack housing 5, and the right end face of the piezoelectric stack 19 is in contact with the left end face of the adjustment screw 18. By adjusting the adjustment screw 18 The axial position of the spool valve 8 can be changed by the feed amount; the left end face of the piezoelectric stack 19 is in contact with the right end face of the output rod 20; the left end face of the output rod 20 is in contact with the moving iron The right end face of the core 14 is in contact, for transmitting the output displacement of the piezoelectric stack 19 to the moving iron core 14; the adjustment block 22 is connected with the piezoelectric stack shell 5 by screws; the disc The spring 21 is placed in the middle of the adjustment block 22 and the output rod 20. By rotating the adjustment block 22, the compression amount of the disc spring 21 can be changed, thereby changing the pre-pressure of the piezoelectric stack 18; The adjusting screw plug 18 is on the same axis as the piezoelectric stack 19, the output rod 20, the disc spring 21, the adjusting block 22, the moving iron core 14 and the spool valve 8 to ensure that All moving parts won't get stuck.

In this embodiment, the working method of the high-frequency digital valve is divided into three modes:

Mode 1, namely high frequency small displacement output mode;

At this time, only the piezoelectric stack 19 works, and the piezoelectric stack 19 pushes the movable iron core 14 to move under the excitation of 120V voltage, thereby driving the spool valve 8 to reciprocate. Due to the high frequency response and small displacement characteristics of the piezoelectric stack, The output flow of the high-frequency digital valve is small, but the resolution is high, so this mode is suitable for low-speed and high-precision conditions;

Mode 2, that is, the low-frequency large-displacement output mode;

At this time, only the moving iron core 14 is working, first the coil 13 is energized, which causes the moving iron core 14 and the static iron core 11 to be magnetized, which further makes the moving iron core 14 move under the action of the magnetic field force, and drives the spool valve 8 to reciprocate. Due to the large displacement and low dynamic characteristics of the electromagnetic drive, the output flow of the high-frequency digital valve is large, but the accuracy is poor, so this mode is suitable for high-speed and low-precision conditions;

Mode 3, that is, high-frequency large-displacement output mode;

As shown in Figure 6, the signal generator outputs a PWM signal, which is amplified by the 24V voltage amplifier to excite the coil 13. Due to the influence of coil inductance and magnetic circuit reluctance, the electromagnetic force increases slowly; The rising edge of the PWM signal will output a pulse signal with a duration of 1ms and an amplitude of 5V. After being amplified by a 120V voltage amplifier, the piezoelectric stack 19 is driven to work. At this time, the moving iron core 14 moves, causing the magnetic circuit reluctance to decrease. (the working air gap is reduced), which further improves the magnetic flux of the magnetic circuit; when the time exceeds 1ms, the piezoelectric stack 19 returns to its original position, which is the electromagnetic drive mode. Due to the instantaneous increase of the magnetic flux of the magnetic circuit, the electromagnetic The force increases rapidly, and the dynamic performance of opening is significantly improved. Finally, the high-frequency digital valve can output large displacement while obtaining high-frequency response. Therefore, this mode is suitable for high-speed and high-precision working conditions.

It can be seen from the above that the working method proposed by the present invention can adjust the working mode in real time according to the actual needs of the controlled object, that is, realize on-demand between the high-frequency small displacement output mode, the low-frequency large-displacement output mode, and the high-frequency large-displacement output mode. Switch, significantly improve work efficiency and control precision.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to those defined by the claims.

Claims (2)

1. A piezoelectric and electromagnetic coil composite driven high-frequency digital valve is characterized by comprising a hydraulic valve body, a left end cover, a coil shell, a right end cover, a piezoelectric stack shell, a hydraulic plug, a spring, a slide valve, a first sealing ring, a second sealing ring, a static iron core, a coil framework, a coil, a movable iron core, a guide sleeve, a triangular magnetic isolation ring, a bolt, an adjusting plug, a piezoelectric stack, an output rod, a disc spring, an adjusting block and a bolt; the hydraulic valve body is provided with a first step, a second step, a third step, a fourth step, a center hole, a first annular groove and a second annular groove; the left end cover is provided with a first inner hole, a second inner hole and a third inner hole; a fifth step and a sixth step are arranged on the slide valve; a seventh step, an eighth step, a ninth step and a tenth step are arranged on the static iron core;

a plurality of P ports are axially arranged on a first step of the hydraulic valve body, a plurality of A ports and a first annular groove are axially arranged on a second step, and a second annular groove is axially arranged on a third step; the first sealing ring and the second sealing ring are respectively arranged in the first annular groove and the second annular groove of the hydraulic valve body; the hydraulic plug is placed in a central hole of the hydraulic valve body, and a left step of the hydraulic plug is in interference fit with the central hole of the hydraulic valve body; the spring is sleeved on a right step of the hydraulic plug, and the right side of the spring is in contact with a fifth step of the slide valve; the slide valve is placed in a central hole of the hydraulic valve body; the fifth step of the slide valve completely covers the port P of the hydraulic valve body, so that no leakage of the port P in an initial state is ensured; the fourth step of the hydraulic valve body is in interference fit with the first inner hole of the left end cover; the seventh step of the static iron core is in clearance fit with the first inner hole of the left end cover, and the eighth step of the static iron core is in interference fit with the second inner hole of the left end cover;

the coil framework is sleeved outside the ninth step of the static iron core; the coil is wound on the coil framework; the movable iron core is placed on the right side of the static iron core, and a step on the left side of the movable iron core penetrates through a center hole of the static iron core and is in contact with a sixth step of the sliding valve; the guide sleeve is sleeved on the outer sides of the tenth step of the static iron core and the step on the right side of the movable iron core; the triangular magnetic isolation ring is welded on the side surface of the guide sleeve, and the welding position can surround the gap between the static iron core and the movable iron core and is used for reducing the magnetic leakage of the main air gap; a third inner hole of the left end cover on the outer circular surface of the coil shell is in interference fit; the right end cover is connected with the coil shell through the bolt;

the piezoelectric stack shell is connected with the right end cover through the bolt; the adjusting plug is connected with the right center hole of the piezoelectric stack shell through threads; the piezoelectric stack is placed on the inner side of a piezoelectric stack shell, the right end face of the piezoelectric stack is in contact with the left end face of the adjusting plug, and the axial position of the slide valve can be changed by adjusting the feeding amount of the adjusting plug; the left end face of the piezoelectric stack is in contact with the right end face of the output rod; the left end surface of the output rod is in contact with the right end surface of the movable iron core and is used for transmitting the output displacement of the piezoelectric stack to the movable iron core; the adjusting block is connected with the piezoelectric stack shell through threads; the disc spring is arranged between the adjusting block and the output rod, and the compression amount of the disc spring can be changed by rotating the adjusting block, so that the pre-pressure of the piezoelectric stack is changed; the adjusting plug, the piezoelectric stack, the output rod, the disc spring, the adjusting block, the movable iron core and the slide valve are positioned on the same axis, so that the problem of clamping stagnation of all moving parts is avoided.

2. A method of operating a high frequency digital valve using a piezo-electric and solenoid compound drive as defined in claim 1, comprising the following three modes:

a first mode, a high-frequency small displacement output mode;

at the moment, only the piezoelectric stack works, the piezoelectric stack pushes the iron core to move under the excitation of voltage, and then the slide valve is driven to do reciprocating motion, and due to the characteristics of high frequency response and small displacement of the piezoelectric stack, the output flow of the high-frequency digital valve is small, but the resolution is high, so that the mode is suitable for the low-speed high-precision working condition;

a second mode, a low-frequency large-displacement output mode;

at the moment, only the movable iron core works, the coil is electrified to cause the movable iron core and the static iron core to be magnetized, the movable iron core is further caused to move under the action of magnetic field force, and the sliding valve is driven to reciprocate;

mode three, a high-frequency large-displacement output mode;

at the moment, the piezoelectric stack and the movable iron core work, and in the initial excitation stage of the coil, the piezoelectric stack works by electricity to push the movable iron core to move, so that the magnetic resistance of the magnetic circuit is reduced, and the magnetic flux of the magnetic circuit is further improved; the piezoelectric stack is recovered to the original position after continuously working for 1ms and is switched into an electromagnetic driving mode, the electromagnetic force is rapidly increased due to the instantaneous improvement of magnetic flux of a magnetic circuit, the opening dynamic performance is remarkably improved, the high-frequency digital valve can maintain large displacement output, and finally the high-frequency digital valve can output large displacement while obtaining high-frequency response, so that the mode is suitable for high-speed and high-precision working conditions.

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