The control system of variable displacement pump and hydraulic moving equipment
Technical field
The present invention relates to variable displacement pump control field, particularly, relate to a kind of control system of variable displacement pump, the invention still further relates to a kind of hydraulic moving equipment.
Background technique
In hydraulic moving equipment such as existing sweeper; Usually adopt running motor to drive the walking arrangement walking; This running motor then adopts variable displacement pump to drive usually; Sense of rotation and the rotating speed of controlling running motor through the sense of rotation and the discharge capacity of controlled variable pump are controlled the direction of travel (advance or retreat) and the speed of travel of hydraulic moving equipment with this.
Variable displacement pump carries displacement control device usually, for example inclined disc type displacement control device.Existing variable displacement pump control system generally includes the variable displacement pump control mechanism, for example foot-operated plate valve or handle valve etc.The fuel-displaced pipeline of this variable displacement pump control mechanism is communicated with the pressure control mouth of the displacement control device of variable displacement pump, thereby the driver comes controlled variable pump delivery control gear through performance variable pump control mechanism, with the controlled variable pump delivery.For example, more particularly, the driver steps on foot-operated plate valve at a certain angle, makes that the hydraulic oil in the fuel-displaced pipeline of riding plate valve has corresponding pressure, and this pressure acts on the displacement control device of variable displacement pump, makes variable displacement pump export corresponding discharge capacity.So the angle that foot-operated plate valve is operated is big more, then the variable pump delivery is big more, otherwise the angle that foot-operated plate valve is operated is more little, and then the variable pump delivery is more little.
The output power of variable displacement pump is directly proportional with the product of the delivery pressure (being the pressure of the oil feed line of variable displacement pump) of variable pump delivery and variable displacement pump.Therefore; In the normal walking process of running mechanism; Under equal-wattage; If the delivery pressure of variable displacement pump is big (promptly need obtain bigger output torque); Then need reduce variable pump delivery (promptly reducing the speed of travel) usually; If the delivery pressure of variable displacement pump less (be required output torque less) then needs to increase variable pump delivery (promptly obtaining the bigger speed of travel) usually.The delivery pressure of variable displacement pump (moment of torsion) is relevant with the load of running motor, and the load of running motor is determined by road conditions.If travel in the smooth-riding surface, the load of running motor is just less, and the delivery pressure of variable displacement pump (moment of torsion) is just less, this moment if expect one faster travelling speed then to step on foot-operated bigger angle of plate valve; If travel on the upward slope road surface, the load of running motor is just bigger, and the delivery pressure of variable displacement pump (moment of torsion) is just bigger, if want that bigger climbing moment of torsion of output then will be stepped on foot-operated less angle of plate valve under onesize power.This angle is very difficult to the location, and experience that can only be through driver oneself according to engine rotation situation (like listening etc.) judgement, is ceaselessly made adjustment with this, finds a desirable walking states, so complicated operation, and labor intensity is big.In addition; As stated; Running mechanism is when going up a slope; Reduction of speed travels and must upwards lift pin and trample angle to reduce foot-operated plate valve, and to step on the operating habit of stepping on the gas at ordinary times just in time opposite with the driver for this, the driver is very easily taken place miss because of custom and will ride plate valve and trample on earth; Causing variable displacement pump can export peak rate of flow promptly climbs with top speed; Load this moment is maximum, and running mechanism is worked under top speed and Maximum Torque, the life-span of the very big loss motor of this meeting; Suppress flame-outly if motor not enough not greatly, also can take place engine power, very easily cause traffic accident under steam suddenly.
Summary of the invention
The control system that the purpose of this invention is to provide a kind of variable displacement pump; Variable displacement pump control mechanism easy operating in this variable displacement pump control system; For example when being used to drive hydraulic moving equipment, be not easy motor to be caused damage and causes traffic accident because of the misoperation of driver.
To achieve these goals; On the one hand; The present invention provides a kind of control system of variable displacement pump; The control system of this variable displacement pump comprises the variable displacement pump control mechanism; The fuel-displaced pipeline of this variable displacement pump control mechanism is communicated with the pressure control mouth of the displacement control device of variable displacement pump; Wherein, Said variable displacement pump control system also comprises the pressure limiting branch road on the other fuel-displaced pipeline that is connected on said variable displacement pump control mechanism; And; When the pressure in the oil feed line of said variable displacement pump during more than or equal to predetermined value, the conducting of said pressure limiting branch road; When the pressure in the oil feed line of said variable displacement pump during less than said predetermined value, said pressure limiting branch road breaks off.
Preferably, said pressure limiting branch road comprises the relief valve and the switch valve of mutual series connection.
Preferably, the control system of this variable displacement pump also comprises controller and the pressure-detecting device that is arranged on the oil feed line of said variable displacement pump, and this pressure-detecting device is connected with said controller with said switch valve.
Preferably, said pressure-detecting device is pressure relay or pressure transmitter.
Preferably, said variable displacement pump is a two-way variable displacement pump, is respectively arranged with said pressure-detecting device on two oil feed lines of this two-way variable displacement pump.
Preferably, the displacement control device of said variable displacement pump is inclined disc type displacement control device.
Preferably, said variable displacement pump control mechanism comprises foot-operated plate valve or handle valve.
Preferably, said switch valve is a two-position two-way solenoid valve.
On the other hand; The present invention also provides a kind of hydraulic moving equipment; This hydraulic moving equipment comprises running motor and the variable displacement pump that drives this running motor, and wherein, said hydraulic moving equipment adopts the control system of variable displacement pump as indicated above to control said variable displacement pump.
Preferably, said hydraulic moving equipment is sweeper.
Through technique scheme, when the pressure in the oil feed line of said variable displacement pump during, the conducting of pressure limiting branch road more than or equal to predetermined value, this moment the variable displacement pump control mechanism for example the actual delivery pressure of foot-operated plate valve be restricted.That is to say; Even driver's misoperation makes the variable displacement pump control mechanism export pressure maximum; Its actual delivery pressure also is limited to the pressure of pressure limiting branch road; Thereby make the variable pump delivery also correspondingly be limited within the predetermined value; Make the speed of travel of hydraulic moving machinery also be restricted; Thereby also make the output power of variable displacement pump obtain restriction, be not easy to cause output power excessive thereby motor caused damage and cause traffic accident because of the misoperation of driver.
Other features and advantages of the present invention will partly describe in detail in embodiment subsequently.
Description of drawings
Accompanying drawing is to be used to provide further understanding of the present invention, and constitutes the part of specification, is used to explain the present invention with following embodiment, but is not construed as limiting the invention.In the accompanying drawings:
Fig. 1 is the schematic block diagram according to the control system of the variable displacement pump of one embodiment of the present invention;
When Fig. 2 shows the pressure limiting branch road conducting of control system of variable displacement pump as shown in Figure 1, the relation of the operation of variable displacement pump control mechanism and variable displacement pump displacement variation.
Description of reference numerals
1 variable displacement pump control mechanism; 2 variable displacement pumps;
21 displacement control devices; 21A pressure control mouth;
11 fuel-displaced pipelines; 3 pressure limiting branch roads;
22 oil feed lines; 31 relief valves;
32 switch valves; 4 pressure-detecting devices;
5 running motors.
Embodiment
Be elaborated below in conjunction with the accompanying drawing specific embodiments of the invention.Should be understood that embodiment described herein only is used for explanation and explains the present invention, is not limited to the present invention.
Shown in Figure 1, according to an embodiment of the present invention, there is provided a variable displacement pump control system, the control system includes a variable pump variable pump control mechanism 1, the variable pump control mechanism 1 of the drain line with a variable pump 2 The displacement control apparatus 21 communicates a pressure control port 21A, wherein said variable displacement pump control system further comprises bypass the control means of said variable displacement pump 1, the drain line 11 on the limit pressure branch 3, and when The variable displacement pump 2, the pressure in the supply line 22 is greater than a predetermined value (the predetermined value of the size can be determined according to the actual situation, for example, the variable pump 2 according to the driving engine of the rated power or the power curve be determined) , said pressure limiting conduction branch 3; when the variable displacement pump 2 pressure in supply line 22 is less than the predetermined value, the limit pressure branch 3 is disconnected.
Through technique scheme, when the pressure in the oil feed line 22 of said variable displacement pump 2 during more than or equal to predetermined value, 3 conductings of pressure limiting branch road, the actual delivery pressure of variable displacement pump control mechanism this moment 1 (for example foot-operated plate valve) is restricted.That is to say; Even driver's misoperation makes variable displacement pump control mechanism 1 export pressure maximum; Its actual delivery pressure also is limited to the pressure of pressure limiting branch road 3; Thereby make the discharge capacity of variable displacement pump 2 also correspondingly be limited within the predetermined value; Make the speed of travel of hydraulic moving machinery also be restricted; Thereby also make the output power of variable displacement pump 2 obtain restriction, be not easy to cause output power excessive thereby motor caused damage and cause traffic accident because of the misoperation of driver.
More particularly, Fig. 2, shows when 3 conductings of pressure limiting branch road for foot-operated plate valve is an example with variable displacement pump control mechanism 1, the relation of trampling angle and variable displacement pump 2 displacement variation of foot-operated plate valve.In the drawings, Pr is the pressure of pressure limiting branch road 3, and Ar representes when the delivery pressure of riding plate valve equals the pressure P r of pressure limiting branch road 3, to ride the angle of trampling of plate valve.As shown in Figure 2, be flex point with Ar, when foot-operated plate valve trample angle less than Ar the time, the discharge capacity of variable displacement pump 2 changes along with the variation of trampling angle; When foot-operated plate valve trample angle greater than Ar the time, the discharge capacity of variable displacement pump 2 is constant all the time, equals to trample angle pairing discharge capacity when being Ar.That is to say that when 3 conductings of pressure limiting branch road, the angle of trampling of foot-operated plate valve extremely works in the interval less than Ar; When foot-operated plate valve trample angle greater than Ar the time; The discharge capacity of oil hydraulic pump 2 still is the corresponding discharge capacity of Ar; Can't increase with the increase of trampling angle; Thereby avoided using hydraulic moving equipment walking at a high speed under high load condition of this variable displacement pump, therefore be not easy to cause output power excessive thereby motor caused damage and cause traffic accident because of the misoperation of driver.
Said pressure limiting branch road 3 can adopt various appropriate formats to realize, for example as a kind of simple and useful embodiment, as shown in Figure 1, this pressure limiting branch road 3 can comprise the relief valve 31 and switch valve 32 of mutual series connection.The pressure of this pressure limiting branch road 3 is the overflow value that relief valve 31 is set, and can make this 3 conductings of pressure limiting branch road or disconnection easily through switch valve 32.Said switch valve 32 can adopt various suitable forms, and for example as shown in Figure 1, this switch valve 32 is a two-position two-way solenoid valve, in particular, is the bi-bit bi-pass Solenoid ball valve.
Said switch valve 32 can manually be operated, and is preferably automatic operation.As shown in Figure 1, the control system of said variable displacement pump also comprises controller (not shown) and the pressure-detecting device 4 that is arranged on the oil feed line 22 of said variable displacement pump 2, and this pressure-detecting device 4 is connected with said controller with said switch valve 32.Thereby, can be through pressure-detecting device 4 pressure on the oil feed line 22 of detection variable pump 2 in real time, controller comes the switching of control switch valve 32 automatically according to this pressure.When the pressure in the oil feed line 22 of said variable displacement pump 2 during more than or equal to predetermined value, controller control switch valve 32 is opened and is made said pressure limiting branch road 3 conductings; When the pressure in the oil feed line 22 of said variable displacement pump 2 during less than said predetermined value, controller control switch valve 32 cuts out and makes said pressure limiting branch road 3 break off.This pressure-detecting device 4 can adopt various suitable forms, for example can be pressure relay or pressure transmitter etc.Said controller also can adopt various suitable forms, and for example PLC etc. can be embedded in the control system of the hydraulic moving machinery of using said variable displacement pump 2.
Said variable displacement pump can be two-way variable displacement pump, is respectively arranged with said pressure-detecting device 4 on two oil feed lines 22 of this two-way variable displacement pump.Can control hydraulic moving machinery through the sense of rotation of control two-way variable displacement pump advances or retreats.The pressure predetermined value of setting to two oil feed lines 22 of two-way variable displacement pump can be provided with respectively according to concrete operating mode, and two pressure predetermined values can be the same or different.
The displacement control device 21 of said variable displacement pump 2 normally variable displacement pump 2 carries, can be according to the concrete form of variable displacement pump 2 and correspondingly adopt various appropriate formats, for example be generally inclined disc type displacement control device.
Said variable displacement pump control mechanism 1 also can be various concrete forms, for example can comprise handle valve or foot-operated plate valve as indicated above.
On the other hand; The present invention also provides a kind of hydraulic moving equipment; This hydraulic moving equipment comprises running motor 5 and the variable displacement pump 2 that drives this running motor 5, and wherein, said hydraulic moving equipment adopts the control system of variable displacement pump as indicated above to control said variable displacement pump 2.Certainly, said variable displacement pump control system can also be applied to other occasions except hydraulic moving equipment.
Said hydraulic moving equipment can be the hydraulic moving equipment of every field, for example can be sweeper of environmental sanitation mechanical field etc.
More than combine accompanying drawing to describe preferred implementation of the present invention in detail; But; The present invention is not limited to the detail in the above-mentioned mode of execution; In technical conceive scope of the present invention; Can carry out multiple simple variant to technological scheme of the present invention, these simple variant all belong to protection scope of the present invention.
Need to prove that in addition each the concrete technical characteristics described in above-mentioned embodiment under reconcilable situation, can make up through any suitable manner.For fear of unnecessary repetition, the present invention is to the explanation no longer separately of various possible compound modes.
In addition, also can carry out combination in any between the various mode of execution of the present invention, as long as it is without prejudice to thought of the present invention, it should be considered as the disclosed content of the present invention equally.