CN101598151B

CN101598151B - Screw full-bridge pilot structure

Info

Publication number: CN101598151B
Application number: CN2009100860825A
Authority: CN
Inventors: 吴帅; 焦宗夏; 阮健; T﹒R﹒巴顿; 俞军涛
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2009-06-03
Filing date: 2009-06-03
Publication date: 2011-10-26
Anticipated expiration: 2029-06-03
Also published as: CN101598151A

Abstract

The invention belongs to the technical field of hydraulic and pneumatic servo control, and discloses a pilot stage structure of a helical full bridge. The pilot stage structure of the helical full bridge includes a pilot control rod, a secondary motion piston, a piston barrel and a piston end cover, and the structure drives a small pilot control rod to rotate or linearly move inside the secondary motion piston through a motor. Cooperate with the piston barrel and the piston end cover to change the hydraulic or pneumatic damping full bridge to push the secondary moving piston to move to achieve the effect of hydraulic or pneumatic amplification, which can be widely used in the design of two-stage proportional servo valves. Compared with the traditional nozzle baffle or jet pilot stage structure, this pilot stage structure has the following advantages: the pilot amplification factor is large, and it is convenient to manufacture large-flow proportional valves and servo valves; the rotational inertia and inertia of the pilot control rod are very small, and the load The torque or load force is extremely small, which is convenient for control and dynamic performance improvement; the pilot stage has a simple structure and is easy to process; the requirement for oil cleanliness is reduced, and the working reliability of the pilot stage is improved.

Description

A kind of screw full-bridge pilot structure

Technical field

The invention belongs to hydraulic pressure, pneumatic servo control technique field, relate to a kind of new type hydraulic or pneumatic helical full-bridge pilot structure.

Background technique

In hydraulic pressure, pneumatic servo control technique field, servovalve is the critical component of hydraulic pressure and pneumatic servo fluid control technique, the existence of power owing to surge, make hydraulic pressure, the pneumatic servo valve core of big flow need promote very big driving force, present electromechanical actuator is difficult to reach the purpose of direct promotion, so the servovalve of big flow generally adopts two-stage or three grades of controls.Traditional nozzle flapper or jet action valve adopt the pneumatic amplification of 2-level hydraulic, solved the design problem of large-capacity valve, but its shortcoming are processing difficulties, and oil cleanliness is required height, and reliability is low.

Summary of the invention

The present invention has proposed a kind of novel screw full-bridge pilot structure in order to solve the problem that existing servovalve exists, and for development new type hydraulic, pneumatic helical full-bridge pilot stage servovalve very high Practical significance is arranged.

Screw full-bridge pilot structure provided by the invention is by the rotation of control guide control rod or the area of straight line motion change variable orifice, make hydraulic damping full-bridge disequilibrium, form pressure reduction promotion secondary moving piston and do straight line motion, make damping full-bridge balance again.This structure can utilize now very ripe electric rotating machine or linear electric motor control technique to realize the control of pilot stage.Guide's control rod loading moment or power are minimum, and is very low to the moment or the thrust requirement of motor, can select very little electric rotating machine of rotary inertia or inertia or linear electric motor for use, makes pilot stage have very high dynamic characteristic.

Screw full-bridge pilot structure of the present invention comprises guide's control rod, secondary moving piston, piston cylinder and four parts of piston end cap, and guide's control rod wherein is a cylindrical structural, and outer surface is processed with spiral chute; The secondary moving piston is processed with symmetrical piston, and paired through flow hole, piston rod one end are processed with the axial center hole of and guide's control rod equal diameters, are used to insert guide's control rod; Piston cylinder cooperates with the secondary moving piston, and the secondary moving piston can axially be slided in piston cylinder.

Described screw full-bridge pilot structure utilizes the spiral chute of guide's control rod and the through flow hole of secondary moving piston to form the variable restrictor area, be variable hydraulic pressure, pneumatic damping, form hydraulic pressure with the fixed orifice on the piston cylinder, the pneumatic damping full bridge structure, rotation or straight line motion by guide's control rod are regulated hydraulic variable, pneumatic damping, make two chambeies formation pressure reduction promotion secondary moving piston straight line motion about piston, the straight-line hydraulic pressure that makes simultaneously of secondary moving piston, the pneumatic damping full-bridge reaches new balance, the corner of guide's control rod or the one-to-one relationship between straight-line displacement and the straight-line displacement of secondary moving piston have been realized, if guide's rod adopts the corresponding ratio that control can realize guide's rod corner and the straight-line displacement of secondary moving piston by design spiral fluted pitch of rotating, if adopt straight movingly, both displacement corresponding relations of one to one will be realized.

Advantage of the present invention is:

1. simple in structure, difficulty of processing is lower, and control mode is flexible.

2. guide's control rod can adopt rotation or straight moving the driving, utilizes ripe electric rotating machine or techniques of linear motor, reduces cost.Guide's control rod loading moment or load force are minimum, and drive motor can be selected very little electric rotating machine of rotary inertia or the very little linear electric motor of inertia for use, make the dynamic characteristic of driving stage reach very high.

3. the damping change scope in adaptive damping hole is big, makes damping full-bridge power gain big.If make circular through flow hole into the square hole parallel with spiral chute, damping full-bridge variable gradient can be bigger and linear more.

4. spiral chute and through flow hole adopt symmetry processing, have natural remaining, have self-cleaning function simultaneously under the situation of arc variable restrictor hole plug, have reduced the requirement to oil cleanliness, have improved reliability greatly.

Description of drawings

Fig. 1 is a spiral pilot structure sectional view of the present invention;

Fig. 2 is guide's control rod structural drawing of the present invention;

Fig. 2 a is guide's control rod spiral fluted sectional view of the present invention;

Fig. 3 is a secondary moving piston structural representation of the present invention;

Fig. 3 a is a secondary moving piston sectional drawing of the present invention;

Fig. 4 is a piston cylinder structural representation of the present invention;

Fig. 4 a is the sectional drawing of piston cylinder of the present invention;

Fig. 5 is a piston end cap cross-sectional view of the present invention;

Fig. 6 is the pneumatic pilot structure schematic diagram of screw hydraulic of the present invention;

Fig. 7 is the hydraulic damping full-bridge schematic diagram of spiral pilot structure of the present invention.

Embodiment

Below in conjunction with accompanying drawing and example spiral pilot structure of the present invention is described in further details.

The invention provides a kind of spiral pilot structure, as shown in Figure 1, this structure comprises guide's control rod 1, secondary moving piston 2, piston cylinder 3, piston end cap 4, described piston cylinder 3 is enclosed within the outside of secondary moving piston 2, and fix by piston end cap 4, described piston end cap 4 plays the effect of sealing and 2 displacements of restriction secondary moving piston, and guide's control rod 1 is realized secondary moving piston straight line motion at secondary moving piston 2 inner back and forth rotation or straight line motions.Be that example illustrates spiral pilot structure of the present invention below with hydraulic pressure, pneumatic situation is suitable for too.

As shown in Figure 2 be the structural representation of guide's control rod 1, described guide's control rod 1 is a cylindrical structural, have axis hole 104 on first end, 102 cross sections of guide's control rod 1, be used for being connected with motor, described motor can be that electric rotating machine can be linear electric motor also, plays guide's control rod 1 rotation or straight-line effect that drive.Second end, 103 outer surfaces of guide's control rod 1 are processed with spiral chute 101, and as Fig. 2 a, spiral chute 101 adopts symmetry processing in pairs, are used for the radial force of balance guide control rod 1.

Be the structural representation of secondary moving piston 2 as shown in Figure 3, described secondary moving piston 2 adopts two rod piston structures, main body is the piston rod 201 of a cylindrical structural, these piston rod 201 1 ends have center hole 202, the internal diameter of center hole 202 is identical with second end, 103 diameters of guide's control rod 1, and second end 103 of guide's control rod 1 is made rotation or straight line motion in center hole 202.The other end of piston rod 201 can connect the motion object, as spool etc.Have piston 204 on the piston rod 201, be respectively arranged with a pair of through flow hole 203 on the piston rod 201 of piston 204 both sides, through flow hole 203 leads to center hole 202, as Fig. 3 a, this a pair of through flow hole 203 all along piston rod 201 radially but has a certain degree, and purpose is to make two through flow holes 203 be in the both sides of a certain spiral chute 101 respectively, through flow hole 203 intersects with the spiral chute 101 of guide's control rod 1, forms variable bowed segments discharge orifice.Through flow hole 203 is the same with spiral chute 101, circumferentially also is into the processing of even number symmetry, with spiral chute 101 numbers coupling, is symmetrically distributed, and the radial force of balance guide's control rod 1 also provides remaining simultaneously.Shown in Figure 4 is the structural representation of piston cylinder 3, and described piston cylinder 3 adopts cylindrical structure, and outer surface is processed annular groove 302 one, and annular groove 302 forms airtight 5, the first spaces, first space, 5 internal communication high-pressure liquids with external casing during work.As Fig. 4 a, in annular groove 302, become certain distance radially to process the fixed orifice 301 that two areas equate along piston cylinder 3, fixed orifice 301 has been communicated with the inside and outside both sides of piston cylinder 3.The internal diameter of piston cylinder 3 is identical with the external diameter of piston 204.Described through flow hole 203 is circular hole or square hole, when through flow hole 203 is circular hole, spiral chute 101 intersects the arc variable orifice of formation with through flow hole 203, arch height is by guide's control rod 1 corner or straight-line displacement decision, bow-shaped area becomes nonlinear change with arch height, in arch height hour, variable gradient is less; When through flow hole 203 is the square hole parallel with spiral chute 101, crossing area will be a rectangle, and rectangular area and rectangle height are linear, and variable gradient is a rectangle length, can select as required.

When the minute impurities particle in the fluid stops up an end variable orifice, cause long-pending the reducing of logical pasta of this throttle orifice, the liquid resistance increases, and makes hydraulic damping full-bridge disequilibrium.Under the pressure reduction in piston about 204 two chambeies, secondary moving piston 2 will produce axial motion, and axial motion will increase the variable restrictor hole area that stops up end, thereby force the impurity in the fluid to pass through throttle orifice 203, avoid blocked.

Shown in Figure 5 is piston end cap 4, and piston end cap 4 is enclosed within secondary moving piston 2 outer surfaces, and per two piston end caps 4 are one group, and piston cylinder 3 fixed constraints on the outer surface of secondary moving piston 2, are played the effect of sealing and limited piston displacement.After the installation, in the both sides of piston 204, the inside of piston cylinder 3 and piston end cap 4 form two spaces, are respectively second space 6 and the 3rd space 7.

Introduce the working principle of spiral pilot structure of the present invention below.

Fig. 6 is the fundamental diagram of spiral pilot structure of the present invention, making the charge oil pressure in first space 5 is PS, pressure in second space 6 is PA, pressure in the 3rd space 7 is PB, described second space 6 and the 3rd space 7 are communicated with first space 5 by the fixed orifice 301 on the piston cylinder 3, pressure P A in second space 6 communicates with center hole 202 and spiral chute 101 right-hand members with the variable bow-shaped area that spiral chute 101 intersects through left side through flow hole 203, and the pressure P B in the 3rd space 7 communicates with center hole 202 and spiral chute 101 right-hand members with the variable bow-shaped area that spiral chute 101 intersects through the right through flow hole 203.Spiral chute 101 right-hand members of guide's control rod 1 communicate with return pressure PT.State shown in Fig. 6 is that two crossing bow-shaped areas equate, promptly variable bowed segments discharge orifice equal and opposite in direction, and the hydraulic damping full-bridge that fixed orifice of the right and left and variable orifice form is in the equilibrium position, PA=PB, secondary moving piston 2 is in the equilibrium position.

Fig. 7 is the hydraulic damping full-bridge schematic diagram of spiral pilot structure of the present invention, and PS is system's charge oil pressure, i.e. the pressure in first space 5.PA and PB are respectively the pressure in two chambeies about piston, i.e. the pressure in second space 6 and the 3rd space 7.Between PS and PA, the PB fixed orifice 301, i.e. fixed hydraulic damping.PT is a system oil return pressure, i.e. the pressure that connected of spiral chute right-hand member.Between PA, PB and the PT variable orifice of the bow-shaped area of spiral chute 101 and through flow hole 203 formation, promptly variable hydraulic damping.Under the initial state of damping bridge balance, the arc variable restrictor hole area that the rotation of guide's control rod or straight line motion will cause spiral chute 101 and the right and left through-flow 203 to form respectively all changes, be that variable hydraulic damping changes, make hydraulic damping full-bridge disequilibrium, PA and PB change, and the secondary moving piston is done straight line motion under the effect of pressure reduction.

Rotate the working principle that is input as this structure of example explanation with guide's control rod 1.When guide's control rod 1 turns an angle, as among Fig. 1 upward to, the bow-shaped area (being the variable restrictor hole area) that spiral chute 101 is communicated with the 3rd space 7 pressure P B increases, the bow-shaped area that is communicated with second space, 6 pressure P A reduces, by liquid resistance principle as can be known, the variable liquid resistive of the 3rd space 7 pressure P B end is little, the variable liquid resistance of second space, 6 pressure P A end increases, by hydraulic pressure full-bridge equilibrium principle, the 3rd space 7 pressure P B will reduce, second space, 6 pressure P A will increase, secondary moving piston 2 will be subjected to thrust to the right, thereby straight line motion to the right, the straight line motion of secondary moving piston 2 makes spiral chute 101 reduce with the bow-shaped area that the 3rd space 7 pressure P B link to each other again, and the bow-shaped area that links to each other with second space, 6 pressure P A increases, when two variable restrictor hole areas equate, variable liquid resistance equates again, PA=PB, and secondary moving piston 2 forms new balance.The straight-line displacement that corresponding secondary moving piston 2 is certain that is the certain corner input of guide's control rod 1, the displacement of the corner of guide's control rod 1 and secondary moving piston 2 becomes one to one to concern.Secondary moving piston 2 is by PA, and the pressure reduction of PB promotes, and has reached the purpose that the guide amplifies.

The input of the straight line of guide's control rod 1 will reach the purpose same with rotating input, here replicate analysis no longer.Difference is: guide's control rod 1 usefulness is rotated input, the proportionate relationship of input corner and 2 displacements of secondary moving piston is by the diameter decision of spiral chute 101 pitch and guide's control rod 1, during the input of guide's control rod 1 straight line, all it doesn't matter for the diameter of the pitch of spiral chute 101 and guide's control rod 1 on the proportionate relationship of guide's control rod 1 and 2 displacements of secondary moving piston and the guide's control rod 1, and the 1 input displacement of guide's control rod forms one to one relation with 2 displacements of secondary moving piston.

Shown in the schematic diagram 6 a kind of feasible spiral chute 101 Hand of spiral and through flow hole 203 position distribution, if select for use another kind of Hand of spiral to need to change the relativeness of through flow hole 203 and spiral chute 101 simultaneously.

Claims

1. A pilot stage structure of a helical full bridge, characterized in that: it comprises a pilot control rod, a secondary motion piston, a piston cylinder and a piston end cap, and the described piston cylinder is enclosed within the secondary motion piston, and passes through the piston end The cover is fixed, and the piston end cover plays the role of sealing and limiting the displacement of the secondary moving piston. The reciprocating rotation or linear movement of the pilot control rod inside the secondary moving piston will push the secondary moving piston through hydraulic or pneumatic secondary amplification. The two-stage moving piston makes linear motion to realize the amplification of hydraulic or pneumatic driving force;

The pilot control rod adopts a cylindrical structure. The first end of the pilot control rod is used to connect with the motor. The outer surface of the second end of the pilot control rod is processed with spiral grooves. The spiral grooves are processed in pairs and symmetrically to balance the pilot control rod. radial force;

The two-stage moving piston adopts a double-rod piston structure, and the main body is a piston rod with a cylindrical structure. One end of the piston rod has a central hole, and the inner diameter of the central hole is the same as the diameter of the second end of the pilot control rod; The other end is connected to the moving object; there is a piston on the piston rod, and a pair of flow holes are respectively arranged on the piston rod on both sides of the piston, and the flow holes lead to the central hole. The pair of flow holes are all along the radial direction of the piston rod But at a certain angle; the flow holes are symmetrically distributed to balance the radial force of the pilot control rod;

The two flow holes are respectively located on both sides of a certain spiral groove, and the flow holes intersect with the spiral groove of the pilot control rod to form a variable arcuate throttle hole;

The piston cylinder adopts a cylindrical structure, and an annular groove is processed on the outer surface. During operation, the annular groove and the outer casing form a closed first space, and the first space communicates with high-pressure fluid inside, forming a certain distance along the piston in the annular groove. Two fixed orifices of equal area are processed radially on the barrel, and the fixed orifices connect the inner and outer sides of the piston barrel.

2. The pilot stage structure of the helical full bridge according to claim 1, wherein the motor is a rotary motor or a linear motor, which drives the pilot control rod to rotate or linearly move.

3. The pilot stage structure of the helical full bridge according to claim 1, characterized in that: the inner diameter of the piston barrel is the same as the outer diameter of the piston.