Piezoelectric crystal digital valve
Technical field
The present invention relates to electric liquid conversion and control element, especially relate to a kind of piezoelectric crystal digital valve.
Background technique
High-speed switch valve is a kind of new digital formula electricity liquid conversion and control element, adopt the pulse flow control mode, realize high-precision Hydraulic Servo Control, have that volume is little, reliability is high, contamination resistance is strong and advantage such as cheap, can substitute the hydraulic efficiency servo-valve of manufacture cost height, resistance tocrocking difference, have wide range of applications.Digital valve realizes trace control to improve response frequency.Can improve response frequency although reduce spool quality and the power of surging, the raising of switch valve response frequency mainly relies on increase driver active force and dwindles the response time.The driver of high-speed switch valve mainly is a strong electromagnet, and the general response time is several milliseconds; High electromagnetic force needs more Number of ampere turns, causes the solenoid valve heating, and complex structure, volume are bigger.Be subjected to factor affecting such as installing space, electromagnetic force, motional inertia, the response capability that further improves solenoid valve has run into restriction.In addition, because switch valve is subjected to the restriction of switching time, spool stroke can not be too big, so the rated flow of digital valve is restricted.Under identical driving force, increase the rated flow of valve, will reduce the speed of response of switch valve.Simultaneously along with the increase of quick closing valve working pressure, cause the surge increase of power of spool, also will reduce the speed of response of switch valve.Therefore, there is the contradiction between high-speed response and high pressure, the big flow in high-speed switch valve.At present both at home and abroad the high-speed solenoid valve of development is difficult to reach simultaneously the response time and is higher than 10L/Min less than 4ms, working pressure greater than 20Mpa, flow, thereby can only be used as pilot valve usually; And the digital valve of using pilot valve to control, although can realize high pressure, big flow, but its frequency response reduces greatly.Therefore, seek next-generation drive, to improve the response capability of straight ejector half high-speed switch valve, the contradiction that solves between high-speed response and high pressure, the big flow is the key that improves the digital valve performance, enlarges its application area.
The piezoelectric crystal driver is a kind of next-generation drive that development in recent years is got up, and has following characteristics:
1) response is fast, can reach GHz.
2) ouput force is big, can reach more than the kN.
3) low in energy consumption, than the low order of magnitude of electromagnetic actuator.
Although piezoelectric crystal can increase substantially the speed of response of switch valve,, be generally tens microns, and the hydrovalve spool travel is all more than the hundreds of micron because the output displacement only accounts for 0.1% of its length; Therefore, solving the problem that the displacement of piezoelectric crystal driver is amplified, is the key of making good use of piezoelectric crystal material.Methods such as the lever amplification of adopting in the world, the displacement amplification of buckling, hydraulic pressure amplification all do not solve piezoelectric crystal micrometric displacement scale-up problem well at present, cause also simultaneously that the piezoelectric crystal ouput force is dwindled, output frequency reduces, therefore, cause the flow of piezoelectric crystal digital valve all very little.
Summary of the invention
The object of the present invention is to provide a kind of piezoelectric crystal digital valve, it is with the driver of piezoelectric crystal as digital valve, utilize the characteristic of its high frequency sound and high ouput force, solve the contradiction between digital valve high frequency sound and high pressure, big flow, overcome under the piezoelectric crystal output displacement the stable problem of output displacement portion under the steady change simultaneously.
The technical solution adopted for the present invention to solve the technical problems is: comprise the ring piezoelectric crystal, and the piezoelectric crystal heap, valve seat, pressure spring, spool, valve gap, valve body, valve body screws nut, and locking nut is regulated bolt; Structure one end of described spool is a large cylinder, and the other end is a spool cone valve part, and the centre is formed by connecting with small cylinder; The ring piezoelectric crystal of dress pressure spring on the endoceliac valve body shoulder of valve, being provided with, spool large cylinder one side contacts with the ring piezoelectric crystal end-face, the spool small cylinder is by behind the pressure spring hole, and the spool cone valve of small cylinder bottom part can be pressed on the hydraulic fluid port of valve seat; One end of piezoelectric crystal heap is with axle sleeve, be placed on the spool great circle styletable, the other end of piezoelectric crystal heap through the protection pad be placed on valve gap on, the adjusting bolt on the valve gap withstands on the protection pad, regulates bolt and fixes with locking nut.Valve body screws nut and valve body passes through scyewed joint.Have the high-voltage oil liquid import on the valve body of spool cone valve part, the O RunddichtringO is housed between valve seat and valve body, seal ring is housed between spool large cylinder and valve body seals high pressure oil p1 in the high-voltage oil cavity in the annular piezoelectric crystal.
It is 2 O RunddichtringOs and 1 PTFE seal ring that seal ring is housed between described spool large cylinder and valve body.
The beneficial effect that the present invention has is:
1) volume is little, adopts piezoelectric crystal as final controlling element, has saved the usage space of valve;
2) the frequency response response is high, can reach more than the 200Hz;
3) working pressure height, output flow is big;
4) performance of valve is not acted upon by temperature changes.
Description of drawings
Fig. 1 is the structure principle chart of piezoelectric crystal digital valve of the present invention.
Fig. 2 is digital valve valve core movement resistance and spool travel schematic representation.
Fig. 3 is a kind of piezoelectric crystal digital valve structure erection drawing of the present invention.
Among the figure: 1, ring piezoelectric crystal, 2, piezoelectric crystal heap, 3, valve seat, 4, pressure spring; 5, spool, 6, valve gap, 7, valve body, 8, valve body screws nut; 9, locking nut, 10, regulate bolt, 11, the protection pad, 12, seal ring; 13, O RunddichtringO, 14, the O RunddichtringO, 15, the valve body shoulder, 16, axle sleeve; A, high-voltage oil liquid import, B, the outlet of digital valve fluid, C, high-voltage oil cavity; 5-1, spool large cylinder, 5-2, spool small cylinder, 5-3, spool cone valve part.A, b are respectively the positive and negative terminal of piezoelectric crystal heap, and c, d are respectively the positive and negative terminal of ring piezoelectric crystal.
Embodiment
Fig. 1 is the structure principle chart of piezoelectric crystal digital valve of the present invention.The present invention includes ring piezoelectric crystal 1, piezoelectric crystal heap 2, valve seat 3, pressure spring 4, spool 5, valve gap 6, valve body 7; Structure one end of described spool 5 is a large cylinder, and the other end is a spool cone valve part, and the centre is formed by connecting with small cylinder; The ring piezoelectric crystal 1 of dress pressure spring 4 in being provided with on the shoulder in valve body 7 chambeies, spool 5 large cylinders one side contacts with ring piezoelectric crystal 1 end face, spool 5 small cylinders are by behind pressure spring 4 holes, the spool cone valve part of small cylinder bottom can be pressed on the hydraulic fluid port of valve seat 3, and piezoelectric crystal heap 2 is placed between spool 5 great circle styletables and the valve gap 6.
Fig. 2 is digital valve valve core movement resistance and spool travel schematic representation.Spool is opening or closing moment, acts on resistance to motion (comprising the power of surging and the hydraulic coupling) maximum on the spool; Along with the increase of spool travel, the valve core movement resistance reduces rapidly.The present invention utilizes piezoelectric crystal high frequency sound, high ouput force characteristic to propose a kind of digital valve structure, adopts 2 piezoelectric crystals to open and close spool respectively.Working principle is as follows: high pressure oil p1 flows into from high-voltage oil liquid import A mouth, and under the effect of high pressure oil p1, spool 5 is crushed on the valve seat 3, and digital valve fluid outlet B mouth is closed, and does not have fluid to flow out from digital valve fluid outlet B mouth.Open spool, as shown in Figure 1a: must be electric when ring piezoelectric crystal 1, piezoelectric crystal is piled 2 dead electricity, the above momentary force F of ring piezoelectric crystal 1 output 1kN
PZT1Promote spool, promote spool 5 accelerated motions, and continue motion under the promotion of the power Fs of pressure spring 4 outputs, run to the position of piezoelectric crystal heap 2 until spool 5, digital valve fluid outlet B mouth is all opened; Close spool, shown in Fig. 1 b: ring piezoelectric crystal 1 dead electricity, piezoelectric crystal heap 2 gets electric, the above momentary force F of piezoelectric crystal heap 2 output 2kN
PZT2Promote spool 5, make spool 5 accelerated motions, and under the effect of high pressure oil p1, continue operation, close up to digital valve fluid outlet B mouth.This digital valve is utilized the high ouput force of the instantaneous generation of piezoelectric crystal, promotes spool high speed operation under high pressure, exports big flow (spool travel can reach more than the 0.2mm).Because what utilize is the impact characteristics of piezo crystals height ouput force, the realization of its output displacement logarithm word valve function does not exert an influence, therefore overcome the unsettled defective of output displacement under the little and temperature variation of piezoelectric crystal output displacement, solved the contradiction between digital valve high frequency sound, high pressure, big flow simultaneously.
Fig. 3 is a kind of piezoelectric crystal digital valve structure erection drawing of the present invention.Comprise ring piezoelectric crystal 1, piezoelectric crystal heap 2, valve seat 3, pressure spring 4, spool 5, valve gap 6, valve body 7, valve body screw nut 8, and locking nut 9 is regulated bolt 10; Structure one end of described spool 5 is large cylinder 5-1, and the other end is spool cone valve part 5-3, and the centre is formed by connecting with small cylinder 5-2; The ring piezoelectric crystal 1 of dress pressure spring 4 in being provided with on the valve body shoulder 15 in valve body 7 chambeies, spool large cylinder 5-1 one side contacts with ring piezoelectric crystal 1 end face, spool small cylinder 5-2 is by behind pressure spring 4 holes, the spool cone valve part 5-3 of small cylinder bottom can be pressed on the hydraulic fluid port of valve seat 3, and B is the outlet of digital valve fluid; One end of piezoelectric crystal heap 2 is with axle sleeve 16, be placed on the spool 5 great circle styletables, the other end of piezoelectric crystal heap 2 through protection pad 11 be placed on valve gap 6 on, the adjusting bolt 10 on the valve gap 6 withstands on protection pad 11, regulates bolt 10 usefulness locking nuts 9 and fixes; Valve body screws nut 8 and passes through scyewed joint with valve body 7.Have high-voltage oil liquid import A on the valve body 7 of spool cone valve part 5-3,7 of valve seat 3 and valve bodies are equipped with O RunddichtringO 13, and 7 of spool large cylinder 5-1 and valve bodies are equipped with 2 O RunddichtringOs 14 and 1 PTFE seal ring 12 and seal high pressure oil p1 among the high-voltage oil cavity C in the annular piezoelectric crystal 1.
The spool large cylinder 5-1 of spool 5 can slide in valve body 7, and the spool cone valve part 5-3 of spool 5 can contact with the hydraulic fluid port of valve seat 3, closes digital valve fluid outlet B.The spool large cylinder 5-1 of spool 5 comes the high pressure oil p1 of sealed high pressure oil pocket C by 2 O RunddichtringOs 14 and 1 PTFE seal ring 12; Piezoelectric crystal is piled 2 one ends and is contacted with the spool upper end, and an end contacts with the lower end surface of protection pad 11; Axle sleeve 16 is used for guaranteeing that piezoelectric crystal heap 2 in movement process, is positioned at shaft core position all the time; Protection pad 11 is used for protecting transistor heap 2 pretightening forces of coming self-regulation bolt 10; Regulate bolt 10 and connect with valve gap 6, come the displacement of regulating spool 5 by screw thread; Locking nut 9 connects with adjusting screw rod 10 by screw thread, is used for locking adjusting bolt 10; One end of valve gap 6 contacts with the upper-end surface of valve body 7, and locatees by valve body shoulder 15, and the other end of valve gap 6 contacts with the interior edge face that valve body screws nut 8; Valve body screws nut 8 and passes through scyewed joint with valve body 7.
Working principle is as follows:
Spool is closed: piezoelectric crystal heap 2 gets electric, the above impact force of output 2kN, and promotion spool 5 quickens descending, and under the effect of high-voltage oil liquid p1, closes digital valve fluid and export B.
Spool is opened: piezoelectric crystal is piled 2 dead electricity, and ring piezoelectric crystal 1 gets electric, the above impact force of output 1kN, and it is up to promote spool 5 acceleration, and under the effect of pressure spring 4 and high-voltage oil liquid p1, opens digital valve fluid and export B.
Digital valve of the present invention adopts the thread cartridge installation form, can be applied to well in the engineering reality.
The present invention adopts valve body to screw nut 8 and valve body 7 passes through scyewed joint, rather than adopts 4 bolts that valve gap 6 is connected with valve body 7, has saved the space of valve.
A, b are respectively the positive and negative terminal of piezoelectric crystal heap, and c, d are respectively the positive and negative terminal of ring piezoelectric crystal, receive the both positive and negative polarity of piezoelectric crystal power-supply controller of electric respectively.
Above-mentioned embodiment is used for the present invention that explains, rather than limits the invention, and in the protection domain of spirit of the present invention and claim, any modification and change to the present invention makes all fall into protection scope of the present invention.