CN107351827B - Hydrostatic drive vehicle traveling braking system - Google Patents
Hydrostatic drive vehicle traveling braking system Download PDFInfo
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- CN107351827B CN107351827B CN201710393285.3A CN201710393285A CN107351827B CN 107351827 B CN107351827 B CN 107351827B CN 201710393285 A CN201710393285 A CN 201710393285A CN 107351827 B CN107351827 B CN 107351827B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T10/00—Control or regulation for continuous braking making use of fluid or powdered medium, e.g. for use when descending a long slope
- B60T10/04—Control or regulation for continuous braking making use of fluid or powdered medium, e.g. for use when descending a long slope with hydrostatic brake
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T15/00—Construction arrangement, or operation of valves incorporated in power brake systems and not covered by groups B60T11/00 or B60T13/00
- B60T15/02—Application and release valves
- B60T15/18—Triple or other relay valves which allow step-wise application or release and which are actuated by brake-pipe pressure variation to connect brake cylinders or equivalent to compressed air or vacuum source or atmosphere
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T7/00—Brake-action initiating means
- B60T7/02—Brake-action initiating means for personal initiation
- B60T7/04—Brake-action initiating means for personal initiation foot actuated
- B60T7/06—Disposition of pedal
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Regulating Braking Force (AREA)
Abstract
The invention relates to a hydrostatic drive vehicle traveling braking system, which belongs to the technical field of hydrostatic drive vehicles and solves the problem of potential safety hazard in braking in the traveling process of the conventional hydrostatic drive vehicle. The invention adopts the matching mode of the hydrostatic closed type traveling system feedback braking and the full hydraulic braking to brake, thereby not only reducing the abrasion of the service brake, but also improving the safety of vehicle braking.
Description
Technical Field
The invention belongs to the technical field of hydrostatic drive vehicles, and particularly relates to a traveling braking system of a hydrostatic drive vehicle.
Background
The hydrostatic transmission system has the advantages of large power-to-volume ratio, wide speed regulation range, large starting torque, flexible element arrangement, convenient reversing, various control modes, reasonable power utilization, easy realization of overload protection, easy remote control and the like, and is widely applied to driving of various walking vehicles.
The hydrostatic driving vehicle traveling brake system in the prior art mainly has two forms, one kind adopts the hydraulic feedback brake system that closed traveling circuit possesses, when needs brake, the rotational speed of loosening throttle engine will reduce and be accompanied by the reduction of closed plunger pump discharge capacity, but because the inertia effect of machinery, closed plunger motor still high-speed rotation, the demand that the output flow of closed plunger pump is less than closed plunger motor can appear this moment, closed plunger motor outlet resistance increases, establish reverse torque on closed plunger motor axle and prevent the vehicle from traveling, vehicle kinetic energy will drive closed plunger motor through the wheel in reverse makes it operate under the operating mode of pump, and establish pressure at closed plunger motor oil-out, force closed plunger pump to drag the engine operation according to the motor operating mode, the kinetic energy of vehicle will be converted into heat energy and absorbed and dissipated by the cooler in engine and the hydraulic system, thereby play the braking effect. The braking mode is mainly used for driving the vehicle by hydrostatic pressure which is usually driven on a horizontal road surface or a road surface with a small gradient and has lower speed, and once a pipeline of a closed walking loop is broken, the whole vehicle can lose the braking capability.
The other braking system consists of two parts, one part is hydraulic feedback braking of the closed walking loop, and the other part is a service brake installed at each wheel end in a full hydraulic braking mode. The braking mode is mainly used for the hydrostatic driving vehicle which has larger load, higher speed and runs on the road surface with larger gradient. Because the two parts of braking systems are independent of each other, the engine flameout phenomenon often occurs in the emergency braking process of the vehicle, the whole vehicle loses power, the phenomena of incapability of steering and the like exist, and certain potential safety hazards exist. This is caused by the fact that the sum of the braking power of the full hydraulic braking system and the driving power consumed by the closed system during emergency braking is greater than the output power of the engine.
Disclosure of Invention
In order to solve the problems in the prior art, the hydrostatic drive vehicle traveling brake system is provided, the hydraulic feedback brake and the full hydraulic brake of the traveling brake system are coordinated, the safety of braking in the traveling process of the hydrostatic drive vehicle is effectively solved, and the safety of vehicle and personnel transportation is ensured.
The invention is realized by adopting the following technical scheme:
the invention provides a hydrostatic drive vehicle walking brake system which comprises a feedback brake part and a full hydraulic brake part of a hydrostatic closed walking system, wherein the full hydraulic brake part comprises a service brake valve, and a pressure control port of the service brake valve is communicated with a pilot pressure port of the feedback brake part of the hydrostatic closed walking system.
Furthermore, the feedback brake part comprises a closed plunger pump, a closed plunger motor, a pilot control handle and a gear pump,
the closed plunger pump is a DA control type inclined disc type axial plunger pump, and the swing angle of an inclined disc in the closed plunger pump is controlled by the pressure of a pilot pressure port.
Furthermore, the service brake valve comprises two three-position three-way proportional pressure reducing valves and a two-position two-way proportional pressure reducing valve, the two three-position three-way proportional pressure reducing valves comprise a first proportional three-way pressure reducing valve and a second proportional three-way pressure reducing valve, the two-position two-way proportional pressure reducing valve is a control valve, and an oil inlet of the two-position two-way proportional pressure reducing valve is a pressure control port.
Furthermore, the full hydraulic brake part also comprises a No. I energy accumulator, a No. II energy accumulator, a first front wheel brake, a second front wheel brake, a first rear wheel brake, a second rear wheel brake and a liquid charging valve;
the first proportional three-way pressure reducing valve is provided with a service brake oil inlet I, a service brake working oil port I and a service brake oil return port I, the second proportional three-way pressure reducing valve is provided with a service brake oil inlet II, a service brake working oil port II and a service brake oil return port II, and the two-position two-way proportional pressure reducing valve is provided with a pressure control oil return port;
the service brake oil inlet I and the service brake oil inlet II of the first proportional three-way pressure reducing valve and the second proportional three-way pressure reducing valve are respectively connected with an energy accumulator I and an energy accumulator II, the service brake working oil port of the first proportional three-way pressure reducing valve is connected with a first front wheel brake and a second front wheel brake, the service brake working oil port of the second proportional three-way pressure reducing valve is connected with a first rear wheel brake and a second rear wheel brake, and the service brake oil return port of the first proportional three-way pressure reducing valve, the service brake oil return port of the second proportional three-way pressure reducing valve and the pressure control oil return port of the two-position two-way proportional pressure reducing valve are respectively connected with a hydraulic oil tank through hydraulic pipelines;
the hydraulic pump is characterized in that the liquid filling valve is a double-loop liquid filling valve and is provided with a liquid filling working oil port I, a liquid filling working oil port II, a liquid filling oil inlet, a liquid filling oil return port and other working oil ports, the liquid filling working oil port I and the liquid filling working oil port II are respectively connected with a No. I energy accumulator and a No. II energy accumulator, the liquid filling oil inlet is connected with an oil outlet of the gear pump, and the liquid filling oil return port is connected with the hydraulic oil tank.
Furthermore, the driving brake valve comprises a control valve core blocking cover, a control valve core return spring, a control valve core, a control valve body, a spring seat assembly II, a control spring, a dust cover II and a control valve core sleeve, wherein the control valve core is installed in the control valve body; the limiting position of the upper end of the control valve core is limited by a positioning ring II and a clamping ring II, the positioning ring II is placed on a shoulder inside the control valve body and is fixed by the clamping ring II arranged in a clamping groove inside the control valve body, a spring seat assembly II, a control spring and a control valve core sleeve are arranged on the upper portion of the control valve core, the control valve body and the control valve core sleeve are sealed, and a dust cover II is arranged outside the control valve body and the control valve core sleeve;
the control valve core and the control valve body form a two-position two-way proportional pressure reducing valve, namely a proportional two-way pressure reducing valve, a feedback oil hole is arranged in the control valve core, and a pressure equalizing groove is arranged at the outer edge of the control valve core.
Furthermore, the service brake valve also comprises an upper valve body assembly and a lower valve body assembly,
the lower valve body assembly comprises a double-loop brake valve core blocking cover, a double-loop brake valve return spring, a lower valve body and a lower valve core, the upper valve body assembly comprises an upper valve core, an upper valve body, a positioning ring I, a clamping ring I, a spring seat assembly I, a rectangular spring, a pressure regulating spring, a double-loop brake valve core sleeve and a dust cover I,
the upper valve body and the lower valve body are fixedly connected and sealed with each other, an upper valve core and a lower valve core are installed in the upper valve body and the lower valve body in the same linear direction, a dual-loop brake valve core blocking cover for limiting the lower end of the lower valve core to move downwards is arranged below the lower end of the lower valve core, a dual-loop brake valve return spring is arranged between the lower end of the lower valve core and the dual-loop brake valve core blocking cover, and the dual-loop brake valve core blocking cover and the lower valve body are fixedly connected and sealed with each other; the upper end of the upper valve core is limited by a positioning ring I and a snap ring I, the positioning ring I is placed on a shoulder inside the upper valve body and is fixed by the snap ring I arranged in a clamping groove inside the upper valve body, the upper part of the upper valve core is provided with a spring seat assembly I, a rectangular spring, a pressure regulating spring and a double-loop brake valve core sleeve, the upper valve body and the double-loop brake valve core sleeve are sealed, a dust cover I is arranged outside the upper valve body and the double-loop brake valve core sleeve,
the upper valve core and the lower valve core respectively form a three-position three-way proportional pressure reducing valve with the upper valve body and the lower valve body, feedback oil holes are formed in the upper valve core and the lower valve core, and pressure equalizing grooves are formed in the outer edges of the upper valve core and the lower valve core.
Further, the diameter of the upper valve core is larger than that of the lower valve core.
Furthermore, the pedal assembly comprises a connecting rod, a roller rotating shaft, a brake pedal, a nut, a bolt II and a pedal rotating shaft,
the brake pedal is connected with the connecting rod through a pedal rotating shaft, is simultaneously connected with the roller through a roller rotating shaft and vertically acts on the compression rod to further act on the connecting rod and further act on the control valve core sleeve and the dual-loop brake valve core sleeve,
and a bolt II for limiting the rotation angle of the brake pedal around the pedal rotation shaft is arranged between the brake pedal and the connecting rod.
Further, the control valve assembly is connected with the upper valve body assembly through a mounting plate.
Furthermore, the closed plunger pump is a DA control type inclined disc type axial plunger pump, an inclined disc control port, namely a pilot pressure port, in the closed plunger pump is communicated with a pressure control port of a service brake valve,
the closed plunger motor is a DA control type bidirectional variable swash plate type axial plunger motor,
the pilot control handle is a direct-acting pressure reduction type control valve and consists of two three-way pressure reducing valves in a parallel structure;
the gear pump is an external gear pump;
the charging valve is a double-loop charging valve and is used for charging the No. I energy accumulator and the No. II energy accumulator simultaneously;
the No. I energy accumulator and the No. II energy accumulator are leather bag type energy accumulators;
the first front wheel brake, the second front wheel brake, the first rear wheel brake and the second rear wheel brake are hydraulic brake spring release type wet brakes,
pump work hydraulic fluid port I and pump work hydraulic fluid port II of closed plunger pump be connected with motor work hydraulic fluid port I and motor work hydraulic fluid port II of closed plunger motor (2), pump pilot signal mouth I and pump pilot signal mouth II of closed plunger pump are connected with handle work hydraulic fluid port I and handle work hydraulic fluid port II of pilot control handle respectively, pump suction port and pump draining port of closed plunger pump are connected with hydraulic tank respectively, pump control pressure mouth I and pump control pressure mouth II of closed plunger pump are connected with motor pilot signal mouth I and motor pilot signal mouth II of closed plunger motor respectively through hydraulic line, the oil supply pressure mouth of closed plunger pump is connected with the handle oil inlet of pilot control handle:
a handle oil return port of the pilot control handle is connected with a hydraulic oil tank through a hydraulic pipeline;
an oil suction port of the gear pump is connected with a hydraulic oil tank through a hydraulic pipeline, and an oil outlet is also connected with an oil inlet of an overflow valve through a hydraulic pipeline;
the oil outlet of the overflow valve is connected with a hydraulic oil tank through a hydraulic pipeline.
Compared with the prior art, the invention has the following beneficial effects:
1. the hydrostatic closed type walking system is adopted to carry out braking in a mode of matching feedback braking with full hydraulic braking, so that the abrasion of a service brake is reduced, and the braking safety of a vehicle is improved;
2. the traveling brake valve of two three-position three-way proportional pressure reducing valves and one two-position two-way proportional pressure reducing valve is adopted, so that the organic combination of the feedback brake and the full hydraulic brake of the static hydraulic closed type traveling system is realized, and the engine flameout phenomenon in the emergency brake process is eliminated;
3. the full hydraulic brake adopts a double-loop brake mode, when one loop breaks down, the other loop can still work normally, and therefore the whole vehicle brake is safer and more reliable.
Drawings
Figure 1 is a schematic diagram of the present invention,
figure 2 is a schematic structural view of a service brake valve according to the present invention,
in the figure: 1-closed plunger pump, 2-closed plunger motor, 3-pilot control handle, 4-gear pump, 5-liquid charging valve, no. 6-I accumulator, no. 7-II accumulator, 8-hydraulic oil tank, 9-first front wheel brake, 10-second front wheel brake, 11-first rear wheel brake, 12-second rear wheel brake, 13-overflow valve, 14-service brake valve,
14.1-dual circuit brake spool cap, 14.2-dual circuit brake valve return spring, 14.3-lower valve body, 14.4-lower valve spool, 14.5-upper valve spool, 14.6-upper valve body, 14.7-retaining ring i, 14.8-retaining ring i, 14.9-spring seat assembly i, 14.10-rectangular spring, 14.11-pressure regulating spring, 14.12-dual circuit brake spool sleeve, 14.13-dust guard i, 14.14-O-ring i, 14.15-O-ring ii, 14.16-control spool cap, 14.17-O-ring iii, 14.18-control spool return spring, 14.19-control spool, 14.20-control valve body, 14.21-spring seat assembly ii, 14.22-control spring, 14.23-Y-ring ii, 14.24-X-ring ii, 14.25-dust guard, 14.26-bolt i, 14.27-pedal link mounting plate ii, 14.28-pedal link mounting plate ii, 14.29-roller mounting plate i, 14.32-roller bearing ring ii, 14.31-14.32-roller bearing assembly ii, 14.16-control spool cap, 14.17-O-ring ii, 14.17-O-ring iii, 14.18-control spool return spring seat assembly ii, 14.18-control spool return spring, 14.19-control spool, 14.20-control spool, 14.14.14.14.14.14.14.14.20-pedal spindle rotation shaft assembly ii, 14.14.14.14.14.14.14.14.14.14.14.14.14.20-pedal spindle adjustment screw,
P 1 service brake oil inlet I, A 1 Service brake working oil port I, T 1 Service brake return I, P 2 Service brake oil inlet II，A 2 Service brake working oil port II, T 2 Service brake oil return II, P 3 -a pressure control port, T 3 -a pressure control return port, ps-a pilot pressure port,
A 3 -liquid-filled working ports I, A 4 Liquid-filled working ports II, P 4 -filling inlet, T 4 -a charge oil return port, O-other working oil ports,
A 9 pump working oil ports I, A 10 -pump working port II, S-pump pumping port T 6 -pump drain port, A 5 Motor working oil port I, A 6 Motor working fluid ports II, Y 1 Pump pilot signal port I, Y 2 Pump pilot signal port II, A 7 Handle working oil ports I, A 8 -handle working oil port II, P 5 -handle oil inlet, T 5 -handle return, Y 3 Motor pilot signal port I, Y 4 Motor pilot signal port II, X 1 Pump control pressure ports I, X 2 Pump control pressure port ii, fa-oil make-up pressure port.
Detailed Description
The embodiments of the present invention will be further explained with reference to the drawings.
A hydrostatic drive vehicle traveling brake system comprises a feedback brake part and a full hydraulic brake part of a hydrostatic closed traveling system, wherein the full hydraulic brake part comprises a service brake valve 14, and a pressure control port P of the service brake valve 14 3 And is communicated with a pilot pressure port Ps of a feedback braking part of the hydrostatic closed-type traveling system.
The full-hydraulic braking part comprises a service braking valve 14, a No. I energy accumulator 6, a No. II energy accumulator 7, a first front wheel brake 9, a second front wheel brake 10, a first rear wheel brake 11, a second rear wheel brake 12 and a liquid charging valve 5.
The closed plunger pump 1 is a DA control type inclined disc type axial plunger pump, control pressure Ps generated by a DA control valve is proportional to the rotating speed of an engine, and the swing angle of an inclined disc in the closed plunger pump 1 is controlled by the pressure of a pilot pressure port Ps.
The closed plunger pump 1 is a DA control type inclined disc type axial plunger pump, and the swing angle of a motor inclined disc is adjusted by the control pressure which is generated by the DA control type inclined disc type axial plunger pump and is related to the rotating speed of an engine and the working pressure of a system; pilot pressure port Ps in closed plunger pump 1 and pressure control port P of service brake valve 14 3 The connection is carried out,
the closed plunger motor 2 is a DA control type bidirectional variable swash plate type axial plunger motor,
the pilot control handle 3 is a direct-acting pressure reduction type control valve and consists of two three-way pressure reducing valves in a parallel structure;
the gear pump 4 is an external gear pump;
the charging valve 5 is a double-loop charging valve and is used for charging the No. I energy accumulator 6 and the No. II energy accumulator 7 at the same time;
the No. I energy accumulator 6 and the No. II energy accumulator 7 are leather bag type energy accumulators;
the first rear wheel brake 11, the second rear wheel brake 12, the first front wheel brake 9 and the second front wheel brake 10 are hydraulic brake spring release type wet brakes,
the pump working oil port IA of the closed plunger pump 1 9 And pump working oil port IIA 10 Motor working oil port IA with closed plunger motor 2 5 And motor working oil port IIA 6 Pump pilot signal port iy of connected, closed plunger pump 1 1 And pump pilot signal port IIY 2 Respectively connected with a handle working oil port IA of a pilot control handle 3 7 And a handle working oil port IIA 8 Oil pumping port S and oil pumping port T of closed plunger pump 1 6 Are respectively connected with a hydraulic oil tank 8, and the pump control pressure port IX of the closed plunger pump 1 1 And pump control pressure port IIX 2 Respectively connected with a motor pilot signal port I Y of the closed plunger motor 2 through a hydraulic pipeline 3 And motor pilot signal port IIY 4 An oil supplementing pressure port Fa of the closed plunger pump 1 is connected with a handle oil inlet P of the pilot control handle 3 5 Connecting:
handle oil return port T of pilot control handle 3 5 Is connected with a hydraulic oil tank 8 through a hydraulic pipeline;
an oil suction port of the gear pump 4 is connected with a hydraulic oil tank 8 through a hydraulic pipeline, and an oil outlet is also connected with an oil inlet of an overflow valve 13 through a hydraulic pipeline;
the oil outlet of the overflow valve 13 is connected with the hydraulic oil tank 8 through a hydraulic pipeline.
The driving brake valve 14 comprises two three-position three-way proportional pressure reducing valves and a two-position two-way proportional pressure reducing valve, the two three-position three-way proportional pressure reducing valves comprise a first proportional three-way pressure reducing valve and a second proportional three-way pressure reducing valve, the two-position two-way proportional pressure reducing valve is a control valve, and an oil inlet of the two-position two-way proportional pressure reducing valve is a pressure control port P 3 。
The first proportional three-way pressure reducing valve is provided with a service brake oil inlet I P 1 Service brake working oil port IA 1 Service braking oil return port I T 1 A service brake oil inlet IIP is arranged in the second proportional three-way pressure reducing valve 2 Service brake working oil port IIA 2 And a service braking oil return port IIT 2, wherein the two-position two-way proportional pressure reducing valve has a pressure control oil return port T 3 ；
Service brake oil inlet IP of first proportional three-way pressure reducing valve and second proportional three-way pressure reducing valve 1 And service brake oil inlet IIP 2 A service braking working oil port A of the first proportional three-way pressure reducing valve is respectively connected with a No. I energy accumulator 6 and a No. II energy accumulator 7 1 A service braking working oil port A of a second proportional three-way pressure reducing valve is connected with a first front wheel brake 9 and a second front wheel brake 10 2 A service braking oil return port T of the first proportional three-way pressure reducing valve is connected with a first rear wheel brake 11 and a second rear wheel brake 12 1 Service brake oil return port T of second proportional three-way pressure reducing valve 2 And a pressure control oil return port T of the two-position two-way proportional pressure reducing valve 3 Are respectively connected with a hydraulic oil tank 8 through a hydraulic pipeline;
the liquid charging valve 5 is a double-loop liquid charging valve and is provided with a liquid charging working oil port IA 3 And a liquid-filled working oil port IIA 4 Liquid filling oil inlet P 4 Liquid-filled oil return port T 4 And other working oil ports O, hydraulic working oil ports IA 3 And a liquid charging working oil port IIA 4 Is respectively connected with the No. I energy accumulator 6 and the No. II energy accumulator 7, and the liquid filling oil inlet P 4 Is connected with an oil outlet of the gear pump 4 and is provided with a liquid-filled oil return port T 4 Is connected with the hydraulic oil tank 8.
The service brake valve 14 structurally comprises a control valve assembly, an upper valve body assembly, a lower valve body assembly and a pedal assembly. The control valve assembly comprises a control valve core blocking cover 14.16, a control valve core return spring 14.18, a control valve core 14.19, a control valve body 14.20, a spring seat assembly II 14.21, a control spring 14.22, a dust cover II 14.25 and a control valve core sleeve 14.35, wherein the control valve core 14.19 is installed in the control valve body 14.20, the control valve core blocking cover 14.16 limiting the downward movement limit position of the control valve core 14.19 is arranged below the lower end of the control valve core 14.19, the control valve core return spring 14.18 is arranged between the lower end of the control valve core 14.19 and the control valve core blocking cover 14.16, and the control valve core blocking cover 14.16 and the control valve body 14.20 are fixedly connected and mutually sealed; the limit position of the upper end of the control valve core 14.19 is limited by a positioning ring II 14.36 and a snap ring II 14.37, the positioning ring II 14.36 is placed on a shoulder inside the control valve body 14.20 and is fixed by the snap ring II 14.37 arranged in a snap groove inside the control valve body 14.20, the upper part of the control valve core 14.19 is provided with a spring seat assembly II 14.21, a control spring 14.22 and a control valve core sleeve 14.35, the control valve body 14.20 and the control valve core sleeve 14.35 are sealed, and a dust cover II 14.25 is arranged outside the control valve body 14.20 and the control valve core sleeve 14.35; the control valve core 14.19 and the control valve body 14.20 form a two-position two-way proportional pressure reducing valve, a feedback oil hole is arranged in the control valve core 14.19, and a pressure equalizing groove is arranged at the outer edge.
The lower valve body assembly comprises a double-loop brake valve core blocking cover 14.1, a double-loop brake valve return spring 14.2, a lower valve body 14.3 and a lower valve core 14.4, the upper valve body assembly comprises an upper valve core 14.5, an upper valve body 14.6, a positioning ring I14.7, a clamping ring I14.8, a spring seat assembly I14.9, a rectangular spring 14.10, a pressure regulating spring 14.11, a double-loop brake valve core sleeve 14.12 and a dust cover I14.13, the upper valve body 14.6 and the lower valve body 14.3 are fixedly connected and sealed with each other, the upper valve core 14.5 and the lower valve core 14.4 are arranged in the upper valve body 14.6 and the lower valve body 14.3 in the same straight line direction, the lower end of the lower valve core 14.4 is provided with the double-loop brake valve core blocking cover 14.1 which limits the downward movement limit position, the double-loop brake valve core spring 14.2 is arranged between the lower end of the lower valve core 14.4 and the double-loop brake valve core blocking cover 14.1, and the lower valve body 14.1 are fixedly connected and the lower valve body 14.1 and sealed with each other; the limiting position of the upper end of an upper valve core 14.5 is limited by a positioning ring I14.7 and a clamping ring I14.8, the positioning ring I14.7 is placed on a shoulder inside an upper valve body 14.6 and is fixed by the clamping ring I14.8 installed in a clamping groove inside the upper valve body 14.6, a spring seat assembly I14.9, a rectangular spring 14.10, a pressure regulating spring 14.11 and a double-loop brake valve core sleeve 14.12 are arranged on the upper portion of the upper valve core 14.5, sealing is achieved between the upper valve body 14.6 and the double-loop brake valve core sleeve 14.12, a dust cover I14.13 is arranged outside the upper valve body 14.6 and the double-loop brake valve core sleeve 14.12, the upper valve core 14.5 and a lower valve core 14.4 respectively form a three-position three-way proportional pressure reducing valve together with the upper valve body 14.6 and a lower valve body 14.3, feedback oil holes are formed inside the upper valve core 14.5 and the lower valve core 14.4, and pressure equalizing grooves are formed in the outer edges. The diameter of the upper valve core 14.5 is larger than that of the lower valve core 14.4. The control valve assembly is connected to the upper valve body assembly by a mounting plate 14.27.
The pedal assembly comprises a connecting rod 14.28, a roller 14.29, a roller rotating shaft 14.30, a brake pedal 14.31, a nut 14.32, a bolt II 14.33 and a pedal rotating shaft 14.34, wherein the brake pedal 14.31 is connected with the connecting rod 14.28 through the pedal rotating shaft 14.34, the brake pedal 14.31 is simultaneously connected with the roller 14.29 through the roller rotating shaft 14.30 and perpendicularly acts on a compression rod 14.41 to further act on the connecting rod 14.28 and further act on a control valve core sleeve 14.35 and a dual-circuit brake valve core sleeve 14.12, and the bolt II 14.33 limiting the rotation angle of the brake pedal 14.31 around the pedal rotating shaft 14.34 is arranged between the brake pedal 14.31 and the connecting rod 14.28.
The working principle of the invention is as follows:
1. the walking process comprises the following steps: the high-pressure oil output by the closed plunger pump 1 directly drives the closed plunger motor 2, the closed plunger pump 1 controls the swing angle direction of a swash plate of the closed plunger pump through a pilot control handle 3, and further controls the static hydraulic drive vehicle to move forward, backward and stop, and the pressure oil in the pilot control handle 3 is provided by a quantitative gear pump arranged in the closed plunger pump 1;
when the rotating speed of the engine is low, the control pressure generated by the fixed-quantity gear pump arranged in the closed plunger pump 1 through the DA control valve is low, and the displacement of the closed plunger motor 2 is not controlled by the control pressure (namely, the pressure control port P) 3 Pressure) control is kept to be full displacement, and the speed regulation of the whole vehicle is completed by the change of the displacement of the closed plunger pump 1 in the process;
when the rotating speed of the engine reaches a certain specific value, the control pressure is increased and the displacement of the closed plunger motor 2 starts to be controlled to change, in the process, the higher the rotating speed of the engine is, the larger the control pressure is, the smaller the displacement of the closed plunger motor 2 is, the larger the working pressure of the system is, the larger the displacement of the closed plunger motor 2 is, and the speed regulation of the whole vehicle is completed by the simultaneous change of the displacement of the closed plunger pump 1 and the displacement of the closed plunger motor 2;
in the walking process, when the load is increased to exceed the rated power of an engine, the rotating speed of the engine is reduced, the flow of a quantitative gear pump arranged in the closed plunger pump 1 is reduced, the control pressure generated by a DA control valve is reduced, the angle of a swash plate is reduced, the displacement of the pump is reduced, and the walking speed of the whole vehicle is reduced; when the load is reduced, the rotating speed of the engine is increased, the flow of the built-in quantitative gear pump is increased, the control pressure generated by the DA control valve is increased, and the angle of the swash plate is increased, so that the displacement of the closed plunger pump 1 is increased, and the traveling speed of the whole vehicle is increased.
2. And (3) braking process: when the brake pedal of the service brake valve 14 is depressed (the stroke is small), the pressure control port P of the two-position two-way proportional pressure reducing valve in the service brake valve 14 3 And pressure control oil return port T 3 The communication is realized, so that the control pressure (namely the pressure of the Ps port) generated by the DA control valve is reduced in proportion, the displacement of the closed plunger pump 1 is reduced, the flow output by the closed plunger pump 1 is smaller than the requirement of the closed plunger motor 2, and the closed plunger motorAnd 2, the outlet resistance is increased, and a reverse torque is built on the shaft of the outlet resistance to prevent the vehicle from running, so that a hydraulic feedback braking effect is generated.
The brake pedal of the service brake valve 14 is continuously stepped on (the stroke is large), and service brake oil inlets IP of two three-position three-way proportional pressure reducing valves in the service brake valve 14 1 And service brake oil inlet IIP 2 Respectively connected with a service brake working oil port IA 1 And service braking working oil port IIA 2 And pressure oil in the energy accumulator I6 and the energy accumulator II 7 is decompressed through a driving brake valve 14 and then respectively enters a first front wheel brake 9, a second front wheel brake 10, a first rear wheel brake 11 and a second rear wheel brake 12, so that full hydraulic braking is realized.
In the process of full hydraulic braking, when the pressure value in any one of the accumulators 6 and 7 is lower than the lower limit value of the charging valve 5, the gear pump 4 charges the accumulators through the charging valve 5, and when the pressure values in the two accumulators are both larger than the upper limit value of the charging valve 5, the charging valve 5 is closed, and the accumulators are stopped from being charged. Two loops formed by the accumulator 6I and the accumulator 7 II and the charging valve 5 are relatively independent, when one loop breaks down, the other loop can still work normally, and the braking of the whole vehicle is safer and more reliable.
In the whole braking process, the feedback braking and the full hydraulic braking of the hydrostatic closed type traveling system are organically combined, the sum of the braking power of the full hydraulic braking system and the driving power consumed by the closed type system is smaller than the output power of an engine, the engine flameout phenomenon in the emergency braking process is eliminated, the modes of firstly braking and then braking by the feedback braking of the hydrostatic closed type traveling system are adopted, the abrasion of front and rear wheel brakes is effectively reduced, and meanwhile, the full hydraulic braking adopts a double-loop braking mode, so that the braking safety of a vehicle is further improved.
The operating principle of the service brake valve 14 is as follows:
when the brake pedal 14.31 is not depressed (initial state), the control valve core 14.19 is pressed against the positioning ring ii 14.36 by the control valve core return spring 14.18, and the positioning ring ii 14 is pressed.36 is fixed by the action of a snap ring II 14.37, and the pressure control port P is arranged at the moment 3 And pressure control oil return port T 3 In a disconnected state; the upper valve core 14.5 and the lower valve core 14.4 are propped against a positioning ring 14.7I under the action of a return spring 14.2 of the double-loop brake valve, the positioning ring I14.7 is fixed under the action of a clamping ring I14.8, and at the moment, a service brake oil inlet IP is arranged at a service brake oil inlet 1 And service brake oil inlet IIP 2 Respectively connected with a service brake working oil port IA 1 And service braking working oil port IIA 2 In a disconnected state, a service braking working oil port IA 1 And a service braking working oil port IIA 2 Respectively connected with a service brake oil return port IT 1 And service braking oil return port IIT 2 Is in a communicating state.
When the brake pedal 14.31 is stepped on, the stroke is small, pedal force acts on the control spring 14.22 through the compression rod 14.41 and the control valve core sleeve 35, and further acts on the control valve core return spring 14.18 through the spring seat assembly II 14.21 and the control valve core 14.19, so that the control valve core 14.19 moves downwards, and the pressure control port P is enabled to be 3 And pressure control oil return port T 3 Communication, by the action of an orifice, of the pressure control port P 3 The pressure of (2) reduces, and then makes closed plunger pump 1's control pressure reduce to make closed plunger pump 1's discharge capacity reduce, the flow of closed plunger pump 1 output this moment is less than closed plunger motor 2's demand, and closed plunger motor 2 exit resistance increases, has set up reverse torque on its axle and has prevented that the vehicle from traveling, produces the quiet hydraulic pressure feedback braking effect.
When the brake pedal 14.31 is continuously stepped down, the stroke is larger until a certain specific displacement is reached, at the moment, pedal force acts on the pressure regulating spring 11 through the compression rod 14.41 and the double-circuit brake valve core sleeve 14.12, and further acts on the double-circuit brake valve return spring 14.2 through the spring seat assembly I14.9, the upper valve core 14.5 and the lower valve core 14.4, so that the upper valve core 14.5 and the lower valve core 14.4 move downwards, and the service brake working oil port IA is respectively caused to move downwards 1 And service braking working oil port IIA 2 And service brake oil return port I T 1 And service braking oil return port IIT 2 The oil way between the brake pads is closed, and the service brake oil inlet is enabled to be in an IP (insulated Gate) state simultaneously 1 And service brakeOil inlet IIP 2 Respectively connected with a service brake working oil port IA 1 And a service braking working oil port IIA 2 And when the hydraulic brake is in a communicated state, the pressure oil in the energy accumulator 6I and the energy accumulator 7 II respectively enters the first front wheel brake 9, the second front wheel brake 10, the first rear wheel brake 11 and the second rear wheel brake 12, so that the full hydraulic brake is realized.
In the braking process, the control valve core 19 acts firstly to reduce the control pressure in the closed plunger pump 1 to realize hydrostatic feedback braking, and then the upper valve core 14.5 and the lower valve core 14.4 act again, so that the abrasion of the service brake is reduced to the maximum extent, the hydrostatic feedback braking is fully utilized, and the safety and the reliability of the vehicle operation are ensured.
Claims (7)
1. A hydrostatic drive vehicle walking brake system comprises a feedback brake part and a full hydraulic brake part of a hydrostatic closed walking system, wherein the full hydraulic brake part comprises a service brake valve (14), and is characterized in that a pressure control port (P3) of the service brake valve (14) is communicated with a pilot pressure port (Ps) of the feedback brake part of the hydrostatic closed walking system;
the feedback brake part comprises a closed plunger pump (1), a closed plunger motor (2), a pilot control handle (3) and a gear pump (4),
the closed plunger pump (1) is a DA control type inclined disc type axial plunger pump, and the swing angle of an inclined disc in the closed plunger pump (1) is controlled by the pressure of a pilot pressure port (Ps);
the driving brake valve (14) comprises two three-position three-way proportional pressure reducing valves and a two-position two-way proportional pressure reducing valve, the two three-position three-way proportional pressure reducing valves comprise a first proportional three-way pressure reducing valve and a second proportional three-way pressure reducing valve, the two-position two-way proportional pressure reducing valve is a control valve, and an oil inlet of the two-position two-way proportional pressure reducing valve is a pressure control port (P3);
the full hydraulic brake part also comprises a No. I energy accumulator (6), a No. II energy accumulator (7), a first front wheel brake (9), a second front wheel brake (10), a first rear wheel brake (11), a second rear wheel brake (12) and a liquid charging valve (5);
the first proportional three-way pressure reducing valve is provided with a service brake oil inlet I (P1), a service brake working oil port I (A1) and a service brake oil return port I (T1), the second proportional three-way pressure reducing valve is internally provided with a service brake oil inlet II (P2), a service brake working oil port II (A2) and a service brake oil return port II (T2), and the two-position two-way proportional pressure reducing valve is provided with a pressure control oil return port (T3);
the service brake oil inlet I (P1) and the service brake oil inlet II (P2) of the first proportional three-way pressure reducing valve and the second proportional three-way pressure reducing valve are respectively connected with a first energy accumulator (6) and a second energy accumulator (7), a service brake working oil port (A1) of the first proportional three-way pressure reducing valve is connected with a first front wheel brake (9) and a second front wheel brake (10), a service brake working oil port (A2) of the second proportional three-way pressure reducing valve is connected with a first rear wheel brake (11) and a second rear wheel brake (12), and a service brake oil return port (T1) of the first proportional three-way pressure reducing valve, a service brake oil return port (T2) of the second proportional three-way pressure reducing valve and a pressure control oil return port (T3) of the two-position two-way proportional pressure reducing valve are respectively connected with a hydraulic oil tank (8) through hydraulic pipelines;
the hydraulic filling valve (5) is a double-loop hydraulic filling valve and is provided with a hydraulic filling working oil port I (A3), a hydraulic filling working oil port II (A4), a hydraulic filling oil inlet (P4), a hydraulic filling oil return port (T4) and other working oil ports (O), the hydraulic filling working oil port I (A3) and the hydraulic filling working oil port II (A4) are respectively connected with a No. I energy accumulator (6) and a No. II energy accumulator (7), the hydraulic filling oil inlet (P4) is connected with an oil outlet of the gear pump (4), and the hydraulic filling oil return port (T4) is connected with a hydraulic oil tank (8).
2. The traveling brake system of the hydrostatic drive vehicle as claimed in claim 1, wherein the traveling brake valve (14) comprises a control valve assembly, the control valve assembly comprises a control spool cover (14.16), a control spool return spring (14.18), a control spool (14.19), a control valve body (14.20), a spring seat component II (14.21), a control spring (14.22), a dust cover II (14.25) and a control spool sleeve (14.35), the control spool (14.19) is installed in the control valve body (14.20), the control spool cover (14.16) limiting the downward movement limit position of the control spool (14.19) is arranged below the lower end of the control spool (14.19), the control spool return spring (14.18) is arranged between the lower end of the control spool (14.19) and the control spool cover (14.16), and the control spool cover (14.16) and the control valve body (14.20) are fixedly connected and sealed with each other; the limiting position of the upper end of the control valve core (14.19) is limited by a positioning ring II (14.36) and a snap ring II (14.37), the positioning ring II (14.36) is placed on a shoulder inside the control valve body (14.20) and is fixed by the snap ring II (14.37) installed in a snap groove inside the control valve body (14.20), a spring seat assembly II (14.21), a control spring (14.22) and a control valve core sleeve (14.35) are arranged on the upper portion of the control valve core (14.19), the control valve body (14.20) and the control valve core sleeve (14.35) are sealed, and a dust cover II (14.25) is arranged outside the control valve body (14.20) and the control valve core sleeve (14.35);
the control valve core (14.19) and the control valve body (14.20) form a two-position two-way proportional pressure reducing valve, namely a proportional two-way pressure reducing valve, a feedback oil hole is arranged in the control valve core (14.19), and a pressure equalizing groove is arranged at the outer edge.
3. The system as recited in claim 2, wherein said service brake valve (14) further comprises an upper valve body assembly and a lower valve body assembly,
the lower valve body assembly comprises a double-loop brake valve core blocking cover (14.1), a double-loop brake valve return spring (14.2), a lower valve body (14.3) and a lower valve core (14.4), the upper valve body assembly comprises an upper valve core (14.5), an upper valve body (14.6), a positioning ring I (14.7), a clamping ring I (14.8), a spring seat assembly I (14.9), a rectangular spring (14.10), a pressure regulating spring (14.11), a double-loop brake valve core sleeve (14.12) and a dust cover I (14.13),
the upper valve body (14.6) is fixedly connected with the lower valve body (14.3) and sealed with each other, an upper valve core (14.5) and a lower valve core (14.4) are installed in the upper valve body (14.6) and the lower valve body (14.3) in the same linear direction, a double-loop brake valve core blocking cover (14.1) for limiting the limit position of downward movement of the lower valve core (14.4) is arranged below the lower end of the lower valve core (14.4), a double-loop brake valve return spring (14.2) is arranged between the lower end of the lower valve core (14.4) and the double-loop brake valve core blocking cover (14.1), and the double-loop brake valve core blocking cover (14.1) is fixedly connected with the lower valve body (14.3) and sealed with each other; the extreme position of the upper end of an upper valve core (14.5) is limited by a positioning ring I (14.7) and a snap ring I (14.8), the positioning ring I (14.7) is placed on a shoulder inside an upper valve body (14.6) and is fixed by the snap ring I (14.8) arranged in a snap groove inside the upper valve body (14.6), the upper part of the upper valve core (14.5) is provided with a spring seat component I (14.9), a rectangular spring (14.10), a pressure regulating spring (14.11) and a double-loop brake valve core sleeve (14.12), the upper valve body (14.6) and the double-loop brake valve core sleeve (14.12) are sealed, and a dust cover I (14.13) is arranged outside the upper valve body (14.6) and the double-loop brake valve core sleeve (14.12),
the upper valve core (14.5) and the lower valve core (14.4) respectively form a three-position three-way proportional pressure reducing valve together with the upper valve body (14.6) and the lower valve body (14.3), feedback oil holes are formed in the upper valve core (14.5) and the lower valve core (14.4), and pressure equalizing grooves are formed in the outer edges of the feedback oil holes and the lower valve core.
4. The service brake system of claim 3, wherein the diameter of the upper spool (14.5) is greater than the diameter of the lower spool (14.4).
5. The hydrostatic drive vehicle service brake system of claim 4, further comprising a pedal assembly including a linkage (14.28), a roller (14.29), a roller pivot (14.30), a brake pedal (14.31), a nut (14.32), a bolt II (14.33), and a pedal pivot (14.34),
the brake pedal (14.31) is connected with the connecting rod (14.28) through a pedal rotating shaft (14.34), the brake pedal (14.31) is simultaneously connected with the roller (14.29) through a roller rotating shaft (14.30) and vertically acts on the compression rod (14.41) to further act on the connecting rod (14.28) and further act on the control valve core sleeve (14.35) and the dual-circuit brake valve core sleeve (14.12),
a bolt II (14.33) limiting the rotation angle of the brake pedal (14.31) around the pedal rotation shaft (14.34) is arranged between the brake pedal (14.31) and the connecting rod (14.28).
6. The service brake system of claim 5, wherein the control valve assembly is coupled to the upper valve body assembly by a mounting plate (14.27).
7. The traveling brake system of a hydrostatically driven vehicle according to one of claims 1 to 6, characterized in that the closed plunger pump (1) is a DA control type swash plate type axial plunger pump, a swash plate control port, i.e., a pilot pressure port (Ps), in the closed plunger pump (1) is communicated with a pressure control port (P3) of a service brake valve (14),
the closed plunger motor (2) is a DA control type bidirectional variable swash plate type axial plunger motor,
the pilot control handle (3) is a direct-acting pressure reduction type control valve and consists of two three-way pressure reducing valves in a parallel structure;
the gear pump (4) is an external gear pump;
the charging valve (5) is a double-loop charging valve and is used for charging a No. I energy accumulator (6) and a No. II energy accumulator (7) simultaneously;
the No. I energy accumulator (6) and the No. II energy accumulator (7) are leather bag type energy accumulators;
the first front wheel brake (9), the second front wheel brake (10), the first rear wheel brake (11) and the second rear wheel brake (12) are hydraulic brake spring release type wet brakes,
pump work hydraulic fluid port I (A9) and pump work hydraulic fluid port II (A10) of closed plunger pump (1) be connected with motor work hydraulic fluid port I (A5) and motor work hydraulic fluid port II (A6) of closed plunger motor (2), pump guide signal mouth I (Y1) and pump guide signal mouth II (Y2) of closed plunger pump (1) are connected with handle work hydraulic fluid port I (A7) and handle work hydraulic fluid port II (A8) of pilot control handle (3) respectively, pump suction port (S) and pump draining port (T6) of closed plunger pump (1) are connected with hydraulic tank (8) respectively, pump control pressure port I (X1) and pump control pressure port II (X2) of closed plunger pump (1) are connected with motor pilot signal mouth I (Y3) and motor pilot signal mouth II (Y4) of closed plunger motor (2) respectively through hydraulic line, the oil supply pressure port (Fa) of plunger pump (1) is connected with the oil inlet of pilot control handle (P5):
a handle oil return port (T5) of the pilot control handle (3) is connected with a hydraulic oil tank (8) through a hydraulic pipeline;
an oil suction port of the gear pump (4) is connected with a hydraulic oil tank (8) through a hydraulic pipeline, and an oil outlet is also connected with an oil inlet of an overflow valve (13) through a hydraulic pipeline;
an oil outlet of the overflow valve (13) is connected with the hydraulic oil tank (8) through a hydraulic pipeline.
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| CN201710393285.3A CN107351827B (en) | 2017-05-27 | 2017-05-27 | Hydrostatic drive vehicle traveling braking system |
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| CN201710393285.3A CN107351827B (en) | 2017-05-27 | 2017-05-27 | Hydrostatic drive vehicle traveling braking system |
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| CN107351827B true CN107351827B (en) | 2023-03-17 |
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| CN108302073A (en) * | 2018-03-26 | 2018-07-20 | 徐工集团工程机械有限公司 | A kind of automobile-used impeller rotating hydraulic system of sand throwing fire extinguishing |
| CN109319693B (en) * | 2018-10-24 | 2019-07-19 | 中南大学 | Hydrostatic lift truck chassis and three-wheel foklift truck with it |
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| GB1463915A (en) * | 1974-03-12 | 1977-02-09 | Orsta Hydraulik Veb K | Trailer brake control system for a vehicle provided with a hydrostatic drive system |
| CN104960513A (en) * | 2015-05-29 | 2015-10-07 | 徐工集团工程机械股份有限公司科技分公司 | Full hydraulic braking and fan driving system |
| CN105459993A (en) * | 2015-12-28 | 2016-04-06 | 中国煤炭科工集团太原研究院有限公司 | Hydraulic system with mechanical and hydraulic combined brake device |
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2017
- 2017-05-27 CN CN201710393285.3A patent/CN107351827B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1463915A (en) * | 1974-03-12 | 1977-02-09 | Orsta Hydraulik Veb K | Trailer brake control system for a vehicle provided with a hydrostatic drive system |
| CN104960513A (en) * | 2015-05-29 | 2015-10-07 | 徐工集团工程机械股份有限公司科技分公司 | Full hydraulic braking and fan driving system |
| CN105459993A (en) * | 2015-12-28 | 2016-04-06 | 中国煤炭科工集团太原研究院有限公司 | Hydraulic system with mechanical and hydraulic combined brake device |
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