CN104085443A - Engineering machine mechanical braking and steering system with preferentially steering front wheels - Google Patents
Engineering machine mechanical braking and steering system with preferentially steering front wheels Download PDFInfo
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- CN104085443A CN104085443A CN201410287959.8A CN201410287959A CN104085443A CN 104085443 A CN104085443 A CN 104085443A CN 201410287959 A CN201410287959 A CN 201410287959A CN 104085443 A CN104085443 A CN 104085443A
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Abstract
The invention discloses an engineering machine mechanical braking and steering system which simultaneously performs preferential steering of front wheels and braking of back wheels when the engineering machine under heavy load is in downhill and four wheels are locked. The engineering machine mechanical braking and steering system comprises a left steering cylinder, a right steering cylinder, a steering valve, a foot brake valve, a rear drive axle, a front drive axle, a rear drive axle and an oil tank, wherein a first priority valve is arranged in an oil-way from the K1 port of the foot brake valve to the front drive axle; when not in steering, the first priority valve functions as a rubber pipe for connecting, thus enabling the brake oil-way of the front drive axles to be connected; after braking, the normal simultaneous braking of front and rear drive axles can be achieved; when the front drive axle needs steering, the first priority valve under the effect of controlling the pressure of oil rapidly cuts off the brake oil-way of the front drive axle, so that the pressure oil of the front drive axle directly returns the oil tank, namely, the braking pressure of the front drive axle is reduced to be zero, and now the front drive axle can smoothly achieve normal steering and back wheels are always in braking states.
Description
Technical field
The present invention relates to the construction machinery and equipment skid steer system that a kind of front-wheel preferentially turns to, specifically one can be in the time of construction machinery and equipment heavy duty descending, and four-wheel, by under the state of locking, carries out front-wheel simultaneously and preferentially turns to the skid steer system of braking with trailing wheel.
Background technology
Construction machinery and equipment is heavily loaded in the situation that, while travelling on smooth-riding surface, chaufeur is stepped on brake pedal, four of complete machine tires are by locking completely often, because construction machinery and equipment car body weight is than large many of family car, be again heavy duty, powerful complete machine inertia makes chaufeur stepping on and to brake always, make the complete locking of wheel, control complete machine speed.Because the speed of construction machinery and equipment is than little many of automobile, unloaded maximum travel speed is generally no more than 40km/h, and the larger complete machine of weight, and the highest unloaded moving velocity is less, and fully loaded time, tractive force can become greatly, and it is less that moving velocity can become.Therefore,, while travelling in smooth-riding surface, chaufeur can be by turning to or shifting to an earlier date brake locking tire with avoiding obstacles in advance.
But in the time of descending, even if the construction machinery and equipment speed of heavy duty is very little, because the draw of gravity and the inertia of complete machine also make chaufeur stepping on and to brake always, make wheel completely by locking, reduce complete machine running velocity, now the wheel of complete machine and vehicle frame become a rigid body, four tire while slipping motions forward, even if chaufeur steering wheel rotation this moment, also cannot change the glide direction of vehicle, complete machine temporarily loses direction control.Due to construction machinery and equipment construction in the wild mostly, the situation on road surface is very complicated, in the time that descending road surface is uneven, road surface just makes complete machine because of the lack of equilibrium that jolts to the application force of complete machine, existing force unbalance, also have the overbalance of moment, under the effect of out-of-balance force, complete machine has just lost control completely.Now, in the time that there is obstacle in the front of complete machine slipping motion, complete machine is in braking state, and front axle tyre is by locking, and complete machine has just completely lost steering capability, in stays, therefore complete machine just in being in extreme danger, thereby cause occurring safety misadventure.
The feature of construction machinery and equipment:
1. car body quality is large, and more much bigger than family car, and the complete machine travelling has powerful inertia, is not easy to be checked car, therefore requires very high to brake system.
2. the speed of a motor vehicle is low, and general unloaded maximum travel speed is no more than 40km/h, far below the maximum speed of automobile, and not taking the transport that runs away as main, but taking can be to restoration in earth-rock construction operation as main.
3. stopping distance is short, once chaufeur touches on the brake, it is maximum that braking force just reaches, and makes tire by locking, and skidding distance is the shortest.Compared with family car, the frequency of utilization of " point is stopped " is few.Especially in heavily loaded descending and emergency braking, must locking tire.
4. because the speed of a motor vehicle is low, therefore after brake, seldom occur that the automobiles such as trailing wheel whipping, sideslip are in the phenomenon of appearance when brake and turning to of running at high speed.
5. the four wheel drives that adopt more, because overall mass is large, the tractive force that can provide in order to make full use of ground, industrial wheeled equipment all adopts even all-wheel drive of four wheel drive, with increasing traction.
6. the hydro-steerings that adopt more, because Engineering Machinery Quality is large, car body heaviness, pure mechanical steering can not overcome the steering resisting torque of car body, and hydro-steering can provide very large steering torque, and turn to sensitive.For this reason, construction machinery and equipment adopts hydro-steering more.
In construction machinery and equipment, traditional design concept is: under normal circumstances, Engineering Machinery Quality is large and the speed of a motor vehicle is low, when brake, does not turn to, and while turning to, does not also brake.This traditional design concept can meet most users' applying working condition.But the operating mode that each client uses is very complicated, for complete machine heavy duty descending operating mode: when braking, need to turn to and can not turn to this problem just to become the defect of traditional design theory.But, for the special operation condition of above-mentioned construction machinery and equipment, there is no at present concrete solution, thus, a kind ofly allow the construction machinery and equipment skid steer system that front-wheel preferentially turns to just to become good solution.
Summary of the invention
For solving the problems of the technologies described above, the invention provides the construction machinery and equipment skid steer system that a kind of front-wheel preferentially turns to.
The present invention is preferentially to turn to as principle, turning to prior to braking is theory, adopt the principle of pressure-gradient control valve: in the time of complete machine heavy duty downhill braking, if when chaufeur need to turn to according to operating mode, pressure-gradient control valve can be realized the brake-pressure of temporary transient releasing propons, propons is preferentially turned to, when turning to after end, pressure-gradient control valve spool self-return, brake system can be recovered rapidly the braking to propons, whole process back axle keeps braking mode always, when realizing braking and turn to, carries out.Due to rear lock, in the time that propons turns to, the force of inertia that the automobile " weight of rear wheel bearing " of running at high speed produces can make complete machine produce the inertia torque around propons, because the quality of automobile is little, rotor inertia is also very little, and speed is very large, inertia torque can make automobile produce relatively rotating around propons, and relatively rotate lasting chronic, relatively rotate angle very large, therefore automobile there will be serious whipping, sideslip, thereby makes the complete get out of hand of automobile, the life security that seriously jeopardizes chaufeur.But the construction machinery and equipment well below automobile driving speed there will not be this phenomenon completely, because rotor inertia is large, the speed of a motor vehicle is low, inertia torque make that complete machine produces around propons to relatively rotate time length very short, relatively rotate angle also very little, therefore there will not be out of control phenomenon completely.For this reason, can realize the construction machinery and equipment skid steer system of rear lock, front-wheel steering.
The present invention is achieved through the following technical solutions: the construction machinery and equipment skid steer system that a kind of front-wheel preferentially turns to, comprises left steering cylinder, right steering cylinder, convertible valve, foot brake valves, rear driving axle, front driving axle, deflector and fuel tank;
Described left steering cylinder is connected with convertible valve with right steering cylinder; E mouth on convertible valve is connected with the second pump, and the D mouth of convertible valve is connected to fuel tank;
L mouth and the R mouth of described deflector are connected to convertible valve, and the T4 mouth of deflector connects fuel tank, and the P4 mouth of deflector is connected with respectively the first pump and the first by pass valve; The described first by pass valve other end is connected to fuel tank;
The P1 mouth of described foot brake valves is connected with propons energy storage, and the K1 mouth of foot brake valves is connected to front driving axle; The P2 mouth of described foot brake valves is connected with back axle energy storage, and the K2 mouth of foot brake valves is connected to rear driving axle; T1, the T2 mouth of foot brake valves are connected to fuel tank;
To the oil circuit of front driving axle, be provided with first pressure-gradient control valve at the K1 of described foot brake valves mouth; Described the first pressure-gradient control valve is a hydraulic control two-bit triplet change-over valve, and the upper P3 of the being mouth of the first pressure-gradient control valve is communicated with K3 mouth, its next T3 of being mouth is communicated with K3 mouth; The P3 mouth of the first pressure-gradient control valve is connected with the K1 mouth of foot brake valves, and the K3 mouth of the first pressure-gradient control valve is connected to front driving axle, and the T3 mouth of the first pressure-gradient control valve is connected to fuel tank; The oil circuit control of the second pressure-gradient control valve in the oil circuit control of the first pressure-gradient control valve and described convertible valve is parallel-connection structure, and the upper control of a first pressure-gradient control valve mouthful U mouth is connected with the C mouth of convertible valve, and the lower control of a first pressure-gradient control valve mouthful V mouth is connected with the F mouth of convertible valve.
It is further: the T1 of the first described by pass valve, the D mouth of convertible valve, foot brake valves and the T3 mouth of T2 mouth and the first pressure-gradient control valve are connected to fuel tank by a precision filter.
The first described pump and the oil inlet of the second pump are connected to fuel tank by a filter.
The present invention accesses the first pressure-gradient control valve in the brake fluid line of front driving axle: in the time not turning to, the function of the first pressure-gradient control valve is equivalent to the sebific duct of connecting, and the brake fluid line of front driving axle keeps connecting, and when after brake, can realize normal forward and backward drive axle and brake simultaneously; In the time that front driving axle need to turn to, the first pressure-gradient control valve is realized fast the brake fluid line that cuts off front driving axle under the effect of control-oil pressure, make the direct oil sump tank of pressure oil of front driving axle, the brake-pressure that is front driving axle is reduced to 0, now, front driving axle just can be realized normal direction of rotation smoothly, and trailing wheel is always in braking state.After having turned to, control presssure oil and retracing spring combined action make the first pressure-gradient control valve spool return, and the pressure oil instantaneous recovery of front driving axle is connected, and after this, front and back drive axle is braking simultaneously just.
Advantage of the present invention:
1. cost increase is very little.The present invention is extra the first pressure-gradient control valve and the associated pipe of increasing in common engineering mechanical braking steering swivel system, therefore, the cost compare hundreds thousand of with construction machinery and equipment, it is little that cost increases.
2. the sensitivity of the first pressure-gradient control valve is very high.The commutation of the first pressure-gradient control valve is by hydraulic oil control, as long as a dozen turn to, the signal of controlling oil pressure just makes the first pressure-gradient control valve spool commutation fast, no matter whether brake, the tire of front driving axle is all in brake off state, thereby can turn to, and turns to back valve core Rapid reset again, front driving axle is again in braking mode, and the control of hydraulic oil is quick on the draw pressure-gradient control valve.
3. the principle of whole skid steer system is simple, easily understands, and breaks down than being easier to judgement, and attendant keeps in repair easy to detect, and maintenance cost is lower, once break down, can get rid of fast.
4. after brake, complete machine has steering capability completely, has improved the safety of complete machine.Realize the incomparable skid steer function of common car; the in the situation that of realizing in needs braking and turn to; carry out avoiding obstacles with the fastest speed and the shortest stopping distance; complete machine still has normal steering capability when seized; thereby ensure the direction control ability of chaufeur to complete machine, the life security of protection chaufeur.Safe in common car.
5. made up the design defect of four-wheel braking theory of traditional four wheel drive, the further perfect safe design theory of construction machinery and equipment.Construction machinery and equipment, in order to utilize complete machine weight to carry out increasing traction by abundant actv., all adopts four wheel drive, and has the place of driving just to have braking, therefore all adopts four-wheel braking.The present invention utilizes the principle of pressure-gradient control valve, in the situation that propons need to be braked and turn to, first turns to rear braking, and trailing wheel keeps braking mode, and " front-wheel steering, trailing wheel are braked " carries out simultaneously, increased comformability and the safety of complete machine.This engineering machinery field at four wheel drive belongs to of the present invention one large innovative point.
6. skid steer system flexibility of the present invention is extensive.Carry out " point is stopped " and braking with locked wheels in smooth-riding surface and carry out in complex road surface operating mode " point is stopped " when braking, complete machine still has propons and first turns to the ability of rear braking.And realized braking to turning to not impact, common car does not have.
Pressure-gradient control valve manufacture easy to process, be easily embodied as the supporting application of complete machine.Can easily be used in practice the survivability that has determined any patent of invention, domestic had ripe pressure-gradient control valve (two-position three-way valve) manufacturing technology, on a lot of construction machinery and equipments, realize specific function with pressure-gradient control valve, therefore the construction machinery and equipment skid steer system that, a kind of front-wheel of the present invention preferentially turns to is easy to realize application on construction machinery and equipment.
8. can alleviate the wearing and tearing of front axle tyre, because propons has been removed brake-pressure temporarily, front-wheel can Free-rolling, therefore when descending turns to, the state that front-wheel rolls in one side turn away, compared with the tire of pure slipping motion, the wearing and tearing that alleviated tire, have extended service life of front axle tyre.
9. this system is easy to be applied.Whole system is because pressure-gradient control valve is easy to process, the extra cost increasing of system is very little, and safety is higher, and system flexibility is very extensive, makes this system easily be promoted and adopt.
10. " oil circuit control adopts parallel-connection structure to turn to realize preferentially " is the most important thinking feature of the present invention.In the brake piping of front driving axle, increase by the first pressure-gradient control valve, the oil circuit control of the first pressure-gradient control valve derives from the oil circuit control of the second pressure-gradient control valve, two oil circuit controls communicate, adopt parallel-connection structure, can ensure that complete machine is in the time turning to, two pressure-gradient control valves are worked simultaneously, respond the pressure signal of oil circuit control simultaneously, thereby the recovery of rear braking is removed and turned to and turn in the braking that realizes smoothly propons.This is the concrete application of mentality of designing of the present invention on construction machinery and equipment.
11. mentality of designing main points are easily laterally promoted.The present invention adopts pressure-gradient control valve to realize preferentially and turns to, if other multiple systems of construction machinery and equipment have impact to steering swivel system, and the level of security turning to is higher than affecting its system, can additionally access pressure-gradient control valve one to one in to the influential system of steering swivel system at each so, and the oil circuit control of multiple pressure-gradient control valves is adopted to parallel-connection structure, be that oil circuit control communicates, thereby can realize the function of interim other system of releasing, allow complete machine preferentially turn to, and turn to after end, other system is just recovered rapidly normal work.
Brief description of the drawings
Fig. 1 is schematic diagram of the present invention;
Fig. 2 is the schematic diagram of convertible valve in Fig. 1;
Fig. 3 is rear each spool working diagram of right steering of brake;
Fig. 4 is rear each spool working diagram of left steering of brake;
Fig. 5 is the schematic diagram to accessing pressure-gradient control valve in influential other system of steering swivel system.
In figure: 1, left steering cylinder; 2, right steering cylinder; 3, convertible valve; 4, propons energy storage; 5, back axle energy storage; 6, foot brake valves; 7, rear driving axle; 8, front driving axle; 9, the first pressure-gradient control valve; 10, fuel tank; 11, filter; 12, precision filter; 13, the first pump; 14, the second pump; 15, the first by pass valve; 16, deflector; 17, right limit valve; 18, left limit valve; 19, shuttle valve; 20, amplifying valve; 21, the second pressure-gradient control valve; 22, the second by pass valve.
Detailed description of the invention
Be below a specific embodiment of the present invention, existing the invention will be further described by reference to the accompanying drawings.
As depicted in figs. 1 and 2, it comprises left steering cylinder 1, right steering cylinder 2, convertible valve 3, foot brake valves 6, rear driving axle 7, front driving axle 8, deflector 16 and fuel tank 10; Convertible valve 3 comprises shuttle valve 19, amplifying valve 20, the second pressure-gradient control valve 21 and the second by pass valve 22; The loculus outlet of left steering cylinder 1 exports with the large chamber of right steering cylinder 2 the B mouth that simultaneously connects shuttle valve 19 in convertible valve 3, and the large chamber outlet of left steering cylinder 1 and the loculus outlet of right steering cylinder 2 connect the A mouth of shuttle valve 19 in convertible valve 3 simultaneously; In convertible valve 3, the L2 mouth of amplifying valve 20 connects the L1 mouth of left limit valve 18, and in convertible valve 3, the R2 mouth of amplifying valve 20 connects the R1 mouth of right limit valve 17; In convertible valve 3, the C mouth of the second pressure-gradient control valve 21 connects the U mouth of the first pressure-gradient control valve 9, and in convertible valve 3, the F mouth of the second pressure-gradient control valve 21 connects the V mouth of the first pressure-gradient control valve 9; The D mouth of convertible valve 3 connects the entrance of precision filter 12, and the E mouth of convertible valve 3 connects the outlet of the second pump 14, and the N mouth of convertible valve 3 is access to other system.
The P1 mouth of the G Kou Yi road pin brake activation valve 6 of propons energy storage 4, other system is accessed on another road of its G mouth; The P2 mouth of the H Kou Yi road pin brake activation valve 6 of back axle energy storage 5, other system is accessed on another road of its H mouth; The K1 mouth of foot brake valves 6 connects the P3 mouth of the first pressure-gradient control valve 9, the K3 mouth of the first pressure-gradient control valve 9 connects the entrance of the brake piping of front driving axle 8, the K2 mouth of foot brake valves 6 connects the entrance of the brake piping of rear driving axle 7, and the T3 mouth of T1 mouth, T2 mouth and first pressure-gradient control valve 9 of foot brake valves 6 connects the entrance of precision filter 12 simultaneously.
The L0 mouth of left limit valve 18 connects the L mouth of deflector 16, and the R0 mouth of right limit valve 17 connects the R mouth of deflector 16; The return opening of the T4 mouth connected tank 10 of deflector 16, the P4 mouth of deflector 16 connects the Y mouth of the first pump 13, another road of Y mouth of the first pump 13 connects the entrance of the first by pass valve 15, the outlet of the first by pass valve 15 connects the entrance of precision filter 12, the entrance of the entrance of the first pump 13 and the second pump 14 is taken over the outlet of filter 11 simultaneously, the return opening of the outlet connected tank 10 of precision filter 12, the oil outlet of the entrance connected tank 10 of filter 11.
When chaufeur is stepped on after brake pedal, the P1 mouth of foot brake valves 6 and K1 mouth are connected, P2 mouth and K2 mouth are connected, the pressure oil of propons energy storage 4 is gone to front driving axle 8 through P3 mouth, the K3 mouth of G mouth, P1 mouth, K1 mouth, the first pressure-gradient control valve, the pressure oil of back axle energy storage 5 is gone to rear driving axle 7 through H mouth, P2 mouth, K2 mouth, front driving axle 8, rear driving axle 7 be braking simultaneously just, and front and back wheel is by locking completely.Now the oriented right steering of complete machine and left-handed turning are to two kinds of situations.
The first situation right steering
As shown in Figure 3, chaufeur turning clockwise bearing circle, the P4 mouth of deflector 16 and R mouth are connected, T4 mouth and L mouth are connected, the hydraulic oil of fuel tank 10 is under the effect of the first pump 13, through filter 11, the first pump 13, the P4 mouth of deflector 16, R mouth enters into convertible valve 3 amplifying valves 20 again R2 mouth through the R0 of right limit valve 17 mouth, R1 mouth, due to the pressure of R2 mouth be greater than L2 mouth (with fuel tank 10 cut-in pressures be 0), the spool that control-oil pressure overcomes the retracing spring promotion amplifying valve 20 of amplifying valve 20 moves to right, now:
Yi mono-tunnel: oil circuit control oil return, the spool of amplifying valve 20 moves to right and makes pressure oil get back to fuel tank 10 through L mouth, the T4 mouth of L1 mouth, L0 mouth and the deflector 16 of the L2 of amplifying valve 20 mouth, left limit valve 18, realizes the oil return of oil circuit control.
Yi bis-tunnels: the A mouth of convertible valve 3 and C mouth are connected, B mouth connect with D mouth (with fuel tank 10 cut-in pressures be 0), because A mouth pressure is higher than B mouth pressure, now shuttle valve 19 is opened, A mouth and the connection of F mouth; Now, the F mouth pressure of the second pressure-gradient control valve 21 and the pressure sum of its retracing spring are greater than the pressure of C mouth, and therefore the spool of the second pressure-gradient control valve 21 moves right, until E mouth and A mouth are connected completely.
Yi tri-tunnels: the F mouth of convertible valve 3 communicates with the V mouth of the first pressure-gradient control valve 9, the C mouth of convertible valve 3 communicates with the U mouth of the first pressure-gradient control valve 9, therefore, the V mouth pressure of the first pressure-gradient control valve 9 and the pressure sum of its retracing spring are greater than the pressure of U mouth, the spool of the first pressure-gradient control valve 9 moves up, the P3 mouth high-pressure oil passage of the first pressure-gradient control valve 9 disconnects, K3 mouth and T3 mouth are connected, the high brake pressure oil of front driving axle 8 returns to fuel tank 10 through K3 mouth, T3 mouth, the precision filter 12 of the first pressure-gradient control valve 9, pressure becomes 0, the braking of front driving axle 8 is removed temporarily for this reason, and tire can Free-rolling.
The A mouth of convertible valve 3 communicates with the loculus of the large chamber of left steering cylinder 1 and right steering cylinder 2, the large chamber of the B mouth of convertible valve 3 and the loculus of left steering cylinder 1 and right steering cylinder 2 is connected, and hydraulic oil is gone to the large chamber of left steering cylinder 1 and the loculus of right steering cylinder 2 through fuel tank 10, filter 11, the second pump 14, the E mouth of convertible valve 3, amplifying valve 20, A mouth under the effect of the second pump 14; And the fluid in the large chamber of the loculus of left steering cylinder 1 and right steering cylinder 2 returns to fuel tank 10 through the B of convertible valve 3 mouth, amplifying valve 20, D mouth, precision filter 12, front driving axle 8 is realized normal turning clockwise under the combined action of left steering cylinder 1, right steering cylinder 2 for this reason.
When chaufeur according to operating mode right-hand turning to finish after, when bearing circle no longer rotates, the P4 mouth of deflector 16 and R mouth disconnect, T4 mouth and L mouth disconnect, although the oil circuit control at amplifying valve 20 two ends is full of pipeline, and the instantaneous reduction of pressure, and the whereabouts of oil circuit is cut off, now the spool of amplifying valve 20 is retracted position in the pressure bottom left of its retracing spring, and moving to left of spool makes the pressure of L2 mouth occur negative pressure, needs repairing; And the pressure of R2 mouth increases, need to extrude unnecessary oil, the fluid that increases the R2 mouth of pressure carries out repairing through the throttling control port of amplifying valve 20 to the L2 mouth that occurs negative pressure, and the oil that R2 mouth is extruded enters and needs the L2 of repairing mouth through restriction, accurately gets back to meta thereby realize spool.
After the valve core reset of amplifying valve 20, the A mouth of convertible valve 3 and E mouth and C mouth disconnect, B mouth and D mouth disconnect, because the pressure of E mouth constantly raises under the effect of the second pump 14, therefore the pressure of C mouth constantly becomes large, until the pressure of C mouth is while being greater than the pressure sum of F mouth pressure and the second pressure-gradient control valve 21 retracing springs, the spool of the second pressure-gradient control valve 21 is just moved to the left, because the spool displacement amount of the second pressure-gradient control valve 21 is very little, the pressure oil of F mouth just has micro-fluid by laying down in whole system, until the E mouth of convertible valve 3 and N mouth are connected completely, from the pressure oil of the second pump 14 through the E of convertible valve 3 mouth, N mouth is gone to other system.
When the C mouth pressure of convertible valve 3 increases, the U mouth pressure of the first pressure-gradient control valve 9 is also increasing, until the U mouth pressure of the first pressure-gradient control valve 9 is greater than the pressure sum of V mouth pressure and its retracing spring, the spool of the first pressure-gradient control valve 9 moves down, now, the K3 mouth of the first pressure-gradient control valve 9 and P3 mouth are connected, and the pressure oil of propons energy storage 4 continues front driving axle 8 to brake through P3 mouth, the K3 mouth of the K1 of foot brake valves 6 mouth, the first pressure-gradient control valve 9.And in whole steering procedure, rear driving axle 7 keeps braking mode always.Thereby completed complete machine under the braking mode right-hand turning to function.
The second situation left steering
As shown in Figure 4, the chaufeur bearing circle that turns left, the P4 mouth of deflector 16 and L mouth are connected, T4 mouth and R mouth are connected, under the effect of the first pump 13, pressure oil is through the P4 mouth of fuel tank 10, filter 11, the first pump 13, deflector 16, L mouth enters into convertible valve 3 amplifying valves 20 again L2 mouth through the L0 of left limit valve 18 mouth, L1 mouth, and the spool of amplifying valve 20 overcomes its retracing spring and is moved to the left under the oil pressure of L2 mouth, now:
Er mono-tunnel: the fluid of the R2 mouth of amplifying valve 20 returns to fuel tank 10 through R mouth, the T4 mouth of the R1 of right limit valve 17 mouth, R0 mouth, deflector 16, realizes the oil return of oil circuit control.
Er bis-tunnels: the spool of amplifying valve 20 moves to left the B mouth of convertible valve 3 and C mouth are connected, A mouth and D mouth connect (with fuel tank 10 cut-in pressures be 0), because B mouth pressure is higher than A mouth pressure, shuttle valve 19 is opened, B mouth and F mouth are connected, the pressure sum of F mouth pressure now and the second pressure-gradient control valve 21 retracing springs is greater than the pressure of C mouth, and therefore the spool of the second pressure-gradient control valve 21 moves right, until E mouth and B mouth are connected completely.
Er tri-tunnels: because the F mouth of convertible valve 3 communicates with the V mouth of the first pressure-gradient control valve 9, C mouth communicates with the U mouth of the first pressure-gradient control valve 9, the pressure sum of the pressure of V mouth and the first pressure-gradient control valve 9 retracing springs is greater than the pressure of U mouth, on the spool of the first pressure-gradient control valve 9, move, K3 mouth and T3 mouth are connected, and the brake-pressure oil of front driving axle 8 returns to fuel tank 10 through K3 mouth, T3 mouth, the precision filter 12 of the first pressure-gradient control valve 9.The braking of front driving axle 8 is removed temporarily for this reason, and tire can Free-rolling.
Hydraulic oil is gone to the large chamber of loculus and the right steering cylinder 2 of left steering cylinder 1 under the effect of the second pump 14 through fuel tank 10, filter 11, the second pump 14, the E mouth of convertible valve 3, amplifying valve 20, B mouth; And the fluid of the large chamber of left steering cylinder 1 and the loculus of right steering cylinder 2 returns to fuel tank 10 through the A of convertible valve 3 mouth, amplifying valve 20, D mouth, precision filter 12, front driving axle 8 is realized and being turned left normally under the combined action of left steering cylinder 1, right steering cylinder 2 for this reason.
When complete machine left-handed turning is after end, when bearing circle no longer rotates, the P4 mouth of deflector 16 and L mouth disconnect, T4 mouth and R mouth disconnect, although the oil circuit control at amplifying valve 20 two ends is full of pipeline, transient pressure reduces, and the whereabouts of oil circuit is cut off, the now spool of amplifying valve 20 return to the right under the pressure of its retracing spring, moving to right of spool makes the pressure of R2 mouth occur negative pressure, needs repairing; And the pressure of L2 mouth increases, need to extrude unnecessary oil, the fluid that increases the L2 mouth of pressure carries out repairing through the throttling control port of amplifying valve 20 to the R2 mouth that occurs negative pressure, and the oil that L2 mouth is extruded enters and needs the R2 of repairing mouth through restriction, thereby realizes the parking position accuracy of spool.
After the valve core reset of amplifying valve 20, the B mouth of convertible valve 3 and E mouth and C mouth disconnect, A mouth and D mouth disconnect, because the pressure of E mouth constantly raises under the effect of the second pump, therefore the pressure of C mouth constantly becomes large, until the pressure of C mouth is while being greater than the pressure sum of F mouth pressure and the second pressure-gradient control valve 21 retracing springs, the spool of the second pressure-gradient control valve 21 is just moved to the left, because the spool displacement amount of the second pressure-gradient control valve 21 is very little, the pressure oil of F mouth just has micro-fluid by laying down in whole system, until the E mouth of convertible valve 3 and N mouth are connected completely, from the pressure oil of the second pump 14 through the E of convertible valve 3 mouth, N mouth is gone to other system.
When the C mouth pressure of convertible valve 3 increases, the U mouth pressure of the first pressure-gradient control valve 9 is also increasing, until the U mouth pressure of the first pressure-gradient control valve 9 is greater than the pressure sum of V mouth pressure and its retracing spring, the spool of the first pressure-gradient control valve 9 moves down, now, the K3 mouth of the first pressure-gradient control valve 9 and P3 mouth are connected, and the pressure oil of propons energy storage 4 continues front driving axle 8 to brake through P3 mouth, the K3 mouth of the K1 of foot brake valves 6 mouth, the first pressure-gradient control valve 9.And in whole process, rear driving axle 7 keeps braking mode always.Thereby complete complete machine turning function left under the braking mode.
Above two kinds of situations, complete machine has retained normal turning function completely.
When after chaufeur loosen the brake, foot brake valves 6 is Rapid reset under the effect of its retracing spring, the K1 mouth of foot brake valves 6 and T1 mouth are connected, K2 mouth and T2 mouth are connected, and the brake-pressure oil of front driving axle 8 returns to fuel tank 10 through K3 mouth, P3 mouth, the K1 mouth of foot brake valves 6, T1 mouth, the precision filter 12 of the first pressure-gradient control valve 9; The brake-pressure oil of rear driving axle 7 returns to fuel tank 10 through the K2 of foot brake valves 6 mouth, T2 mouth, precision filter 12.Thereby realize complete skid steer process.
After brake finishes, the working diagram of each spool is as Fig. 1.
Continuous several times is stepped on after brake pedal, and the pressure of the G mouth of propons energy storage 4, the H mouth of back axle energy storage 5 can reduce, and the topping up of propons energy storage 4, back axle energy storage 5 is completed by other system to recover its rated pressure.
The function of the first by pass valve 15 is: in the time that the Y mouth pressure of the first pump 13 is elevated to its rated pressure, the first by pass valve 15 is opened, and high pressure oil returns to fuel tank 10 through the first by pass valve 15, precision filter 12, the Hydraulic Elements in protection oil circuit.
The function of right limit valve 17 is: when complete machine right-hand turning to time, RO mouth pressure is higher than R1 mouth, in the time that right steering arrives end position, the position-limited lever of right limit valve 17 is touched, position-limited lever drives the commutation that moves right of the spool of right limit valve 17, thereby the RO mouth, the R1 mouth that have cut off right limit valve 17, right-hand turning is to termination.Now when complete machine left-handed turning to time, the oil circuit control of the R2 mouth of convertible valve 3 is opened the check valve of right limit valve 17 through the R1 of right limit valve 17 mouth, pass through again the oil return of R0 mouth, when complete machine left-handed turning is after very little angle, avoid behind limit on the right-right-hand limit position, the retracing spring of right limit valve 17 promotes the spool commutation that moves to left, and fluid returns to fuel tank 10 through R1 mouth, R0 mouth.
The functional equivalent of left limit valve 18 is in right limit valve 17.
The function of the second by pass valve 22 is: in the time that convertible valve 3 is elevated to its rated pressure towards the pressure of steering cylinder; the second by pass valve 22 is opened; high pressure oil returns to fuel tank 10 through D mouth, the precision filter 12 of the second by pass valve 22, convertible valve 3, the Hydraulic Elements in protection oil circuit.
When whole system does not touch on the brake, brake system does not produce any impact to steering swivel system, and steering swivel system does not produce any impact to brake system.When not touching on the brake, braking fluid and the fuel tank 10 of front driving axle 8 are connected, and while turning to, after moving on the spool of the first pressure-gradient control valve 9, the braking fluid of front driving axle 8 and fuel tank 10 are still connected, for this reason, the spool displacement of the first pressure-gradient control valve 9 does not affect front driving axle 8 brakes the pressure of fluid, and steering swivel system does not affect brake system.Therefore with do not have the overall performance of this " skid steer system " identical.
And step on while brake, after brake system generation effect, the effect of this system is in the time that front driving axle 8 needs braking simultaneously and turns to, and preferentially turns to, and then braking.Allow steering swivel system exert an influence to brake system, preferentially turn to thereby realize, turn to after end, front driving axle 8 continues to keep braking mode.
The oil circuit control of the oil circuit control of the first pressure-gradient control valve 9 and the second pressure-gradient control valve 21 is connected in parallel, can ensure that complete machine is in the time turning to, work when two pressure-gradient control valves, respond the pressure signal of oil circuit control, thereby the recovery of rear braking mode is removed and is turned to and turn in the braking that realizes front driving axle 8 simultaneously.
The present invention has adopted two pressure-gradient control valves to realize preferentially and has turned to, if other multiple systems of construction machinery and equipment have impact to steering swivel system, and the level of security turning to is higher than affecting its system, can additionally access pressure-gradient control valve one to one in to the influential system of steering swivel system at each so, and the oil circuit control of multiple pressure-gradient control valves is adopted to parallel-connection structure, be that oil circuit control communicates, thereby can realize the function of interim other system of releasing, allow complete machine preferentially turn to, and turn to after end, other system is just recovered rapidly normal work.This mentality of designing also should belong to the protection main points of patent of the present invention so.This mentality of designing schematic diagram refers to Fig. 5
As shown in Figure 5: Third Road system, Si road system ... X road system is in the time of work, suppose that steering swivel system cannot normally work, when the level of security turning to is during higher than other system, can between the control system of " Third Road system " and " Third Road system ", access the 3rd pressure-gradient control valve respectively, between the control system of " Si road system " and " Si road system ", access the 4th pressure-gradient control valve ... between " X road system " and the control system of " X road system ", access X pressure-gradient control valve (X is greater than 2 natural number), and pressure-gradient control valve control port adopts parallel-connection structure, it is U-3 mouth, U-4 mouth ... U-X mouth connects the U mouth of the second pressure-gradient control valve 9 simultaneously, V-3 mouth, V-4 mouth ... V-X mouth connects the V mouth of the second pressure-gradient control valve 9 simultaneously, and P-3 mouth, P-4 mouth ... P-X mouth connects respectively corresponding oil circuit control, K-3 mouth, K-4 mouth ... K-X mouth connects respectively the oil circuit of corresponding actuating system, T-3 mouth, T-4 mouth ... T-X mouth is connected tank simultaneously.So, can realize preferentially and turning to, the interim break-off of other system, waits and turns to after end, and other system is recovered again normal work.
Claims (3)
1. the construction machinery and equipment skid steer system that front-wheel preferentially turns to, comprises left steering cylinder (1), right steering cylinder (2), convertible valve (3), foot brake valves (6), rear driving axle (7), front driving axle (8), deflector (16) and fuel tank (10);
Described left steering cylinder (1) is connected with convertible valve (3) with right steering cylinder (2); E mouth on convertible valve (3) is connected with the second pump (14), and the D mouth of convertible valve (3) is connected to fuel tank (10);
The L mouth of described deflector (16) and R mouth are connected to convertible valve (3), and the T4 mouth of deflector (16) connects fuel tank (10), and the P4 mouth of deflector (16) is connected with respectively the first pump (13) and the first by pass valve (15); Described the first by pass valve (15) other end is connected to fuel tank (10);
The P1 mouth of described foot brake valves (6) is connected with propons energy storage (4), and the K1 mouth of foot brake valves (6) is connected to front driving axle (8); The P2 mouth of described foot brake valves (6) is connected with back axle energy storage (5), and the K2 mouth of foot brake valves (6) is connected to rear driving axle (7); The T1 of foot brake valves (6), T2 mouth are connected to fuel tank (10);
It is characterized in that:
K1 mouth at described foot brake valves (6) is provided with first pressure-gradient control valve (9) to the oil circuit of front driving axle (8); Described the first pressure-gradient control valve (9) is a hydraulic control two-bit triplet change-over valve, and the upper P3 of the being mouth of the first pressure-gradient control valve (9) is communicated with K3 mouth, its next T3 of being mouth is communicated with K3 mouth; The P3 mouth of the first pressure-gradient control valve (9) is connected with the K1 mouth of foot brake valves (6), and the K3 mouth of the first pressure-gradient control valve (9) is connected to front driving axle (8), and the T3 mouth of the first pressure-gradient control valve (9) is connected to fuel tank (10); The oil circuit control of the second pressure-gradient control valve (21) in the oil circuit control of the first pressure-gradient control valve (9) and described convertible valve (3) is parallel-connection structure, the upper control of the first pressure-gradient control valve (9) mouthful U mouth is connected with the C mouth of convertible valve (3), and the lower control of the first pressure-gradient control valve (9) mouthful V mouth is connected with the F mouth of convertible valve (3).
2. the construction machinery and equipment skid steer system that a kind of front-wheel according to claim 1 preferentially turns to, is characterized in that: the T1 of described the first by pass valve (15), the D mouth of convertible valve (3), foot brake valves (6) and the T3 mouth of T2 mouth and the first pressure-gradient control valve (9) are connected to fuel tank (10) by a precision filter (12).
3. the construction machinery and equipment skid steer system that a kind of front-wheel according to claim 1 preferentially turns to, is characterized in that: described the first pump (13) and the oil inlet of the second pump (14) are connected to fuel tank (10) by a filter (11).
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410287959.8A CN104085443B (en) | 2014-08-06 | 2014-08-06 | The engineering machinery skid steer system that a kind of front-wheel preferentially turns to |
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| CN201410287959.8A CN104085443B (en) | 2014-08-06 | 2014-08-06 | The engineering machinery skid steer system that a kind of front-wheel preferentially turns to |
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| CN104085443A true CN104085443A (en) | 2014-10-08 |
| CN104085443B CN104085443B (en) | 2016-05-25 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107323446A (en) * | 2017-06-30 | 2017-11-07 | 燕山大学 | Braking control system and its control method applied to hydraulic closed drive system |
| GB2572393A (en) * | 2018-03-28 | 2019-10-02 | Caterpillar Inc | Hydraulic system for a machine |
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| CN203974933U (en) * | 2014-08-06 | 2014-12-03 | 徐工集团工程机械股份有限公司 | The construction machinery and equipment skid steer system that a kind of front-wheel preferentially turns to |
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| US3847243A (en) * | 1972-10-27 | 1974-11-12 | Allis Chalmers | Auxiliary power system on a vehicle |
| CN201553138U (en) * | 2009-11-12 | 2010-08-18 | 浙江军联机械电子控股有限公司 | Loading machine walking hydraulic braking system mechanism |
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| CN107323446A (en) * | 2017-06-30 | 2017-11-07 | 燕山大学 | Braking control system and its control method applied to hydraulic closed drive system |
| GB2572393A (en) * | 2018-03-28 | 2019-10-02 | Caterpillar Inc | Hydraulic system for a machine |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104085443B (en) | 2016-05-25 |
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