CN101899850A

CN101899850A - Control method and device for reducing starting load of excavator

Info

Publication number: CN101899850A
Application number: CN 201010239609
Authority: CN
Inventors: 戴晴华; 权喜
Original assignee: Sany Heavy Machinery Ltd
Current assignee: Sany Heavy Machinery Ltd
Priority date: 2010-07-29
Filing date: 2010-07-29
Publication date: 2010-12-01
Anticipated expiration: 2030-07-29
Also published as: CN101899850B

Abstract

The invention discloses a control method for reducing the starting load of an excavator, which is characterized in that: an electromagnetic valve control switch is turned on, when the excavator starts; a pilot oil pump outputs pilot pressure oil from an electromagnetic valve port A and the pilot pressure oil flows into a standby valve to push the standby valve to start; a rear pump outputs hydraulic oil to an oil port BO of the standby valve through the standby valve; a bypass oil return pipeline is formed by communicating the oil port BO and an oil port AO of the standby valve; the hydraulic oil flows back to the standby valve from the oil port AO and then flows back to an oil tank to complete the starting process; the device for reducing the starting load of the excavator comprises the electromagnetic valve control switch and an electromagnetic valve, wherein an oil inlet P of the electromagnetic valve is connected to an oil outlet of the pilot oil pump; an output port A of the electromagnetic valve is connected with a control oil port X of the standby valve; and an oil return port T of the electromagnetic valve is connected to the oil return pipeline. By arranging the bypass oil return pipeline, the hydraulic oil bypasses an oil return box when the device is started, so the loss of the pressure and the starting load of an engine are reduced and the starting is realized at the low temperature.

Description

A kind of control method and device that reduces starting load of excavator

Technical field

The present invention relates to a kind of excavator control method and device, be specifically related to a kind of control method and device that reduces starting load of excavator.

Background technology

Hydraulic crawler excavator is a kind of common engineering machinery, has been widely used in every profession and trades such as building, water conservancy.Its power section mainly is made up of motor, hydraulic pump, and motor drives the oil pump rotation, and the pressure oil of oil pump outlet is distributed to each equipment by the work spool, and pressure oil acting back low pressure is got back to fuel tank.

In order to make static motor enter duty, must be earlier with external force rolling motor bent axle, make piston begin to move up and down, suck combustion mixture in the cylinder, and with its compression, light, volume expands rapidly and produces powerful power, promotes piston motion and drives crankshaft rotating, and motor could automatically enter working cycles.The bent axle of motor begins to turn to the overall process of motor auto idle speed running under external force, is called the starting process of motor, finishes the needed device of starting in starter.Motor is when starting, except bringing onto load (oil pump, fan etc.), also to overcome various component frictional resistance, simultaneously also will be to actings such as self inside lubricating oil pump, water pumps, especially when motor started under low-temperature condition, 1. the hydraulic oil viscosity was big, and the resistance of ducting is big, the pressure loss is big, and the power of required motor is also just big more; 2. the viscosity of engine motor oil increases, and the engine interior power demand increases, and the required starting power of motor also just increases; 3. engine fuel mist temperature is low relatively, does not reach the burning-point requirement.

Comprehensive the above, in engine starting process, when temperature is low more, the required starting power of motor increases, and motor starts by starter when just starting, starter is less with respect to the power of motor, if the maximum starting power of starter less than the power of load, motor does not just start so.In this case, normally adopt the intake air preheater of additional cold start preheating device, when piloting engine, behind the connection preheater switch, heating wire energising temperature raises and valve body is heated.Valve body is subjected to thermal stretching and drives spool to move down, and its tapering point leaves fuel feed hole.Fuel oil flows into body cavity and vaporizes because of being heated, and from the body cavity ejection, and is lighted generation flame by red-hot heating wire and sprays into admission line, makes air inlet obtain preheating.When cutting off preheating switch, the heating wire cut-off, the valve body temperature reduces and shrinks, and moves to make tapering point block fuel feed hole fray-out of flame and stop preheating on the spool.Engine charge or machine oil are carried out preheating, to reach the purpose that reduces starting power.Yet, adopt preheating device to cost an arm and a leg, and need to increase by one tunnel control circuit preheater, increase maintenance cost.

Summary of the invention

The object of the invention provides a kind of control method and device that reduces starting load of excavator, by using this control method and device, reduces starting load, and excavator can easily be started at low temperatures.

For achieving the above object, the technical solution used in the present invention is: a kind of control method that reduces starting load of excavator, when excavating machine starting, open the solenoid control switch, guide's oil pump output pilot pressure oil flows into service valve from the output of electromagnetic valve A mouth and promotes the service valve unlatching, back pump output hydraulic oil process service valve is to service valve hydraulic fluid port BO, hydraulic fluid port BO is communicated with formation bypass return line with service valve hydraulic fluid port AO, hydraulic oil flows back to service valve from hydraulic fluid port AO, flow back to fuel tank again, after finishing start-up course, close the solenoid control switch.

A kind of device that reduces starting load of excavator, comprise a solenoid control switch and an electromagnetic valve, described electromagnetic valve oil inlet P is connected on the oil-out of guide's oil pump, the delivery outlet A of this electromagnetic valve is connected with the control port X mouth of standby spool, and the oil return inlet T of described electromagnetic valve is connected on the return line.

In the technique scheme, described electromagnetic valve is generally to use at present, is the automation foundation element that is used for controlling flow direction, belongs to actuator, is generally used in the machinery control medium direction being controlled, thereby reaches control to valve switch.Among the present invention, by be connected an electromagnetic valve with standby spool, and come the keying of control electromagnetic valve by the solenoid control switch, when engine start, solenoid control switch opens control electromagnetic valve is opened, guide's oil pump output guide oil enters the electromagnetic valve from the electromagnetic valve oil inlet P, the control port X of the fuel-displaced inflow service valve of delivery outlet A of electromagnetic valve, promote service valve to right position, service valve hydraulic fluid port BO is communicated with formation bypass return line with hydraulic fluid port AO, pump hydraulic fluid port after making and directly be communicated with the bypass return line, hydraulic oil has reduced like this and has flow through the pressure loss that choke valve causes by standby spool oil sump tank, the pressure step-down of pumping hole, the required power of pump is also low, thus motor with load also light, become light thereby make to start; Behind engine start, close the solenoid control switch, electromagnetic valve resets, and guide oil is entered from oil return inlet T by electromagnetic valve P mouth and is back to the return line, returns fuel tank, and service valve resets and cuts off bypass return line, the normal engineering of oil pump, excavator normal operation.

Because the technique scheme utilization, the present invention compared with prior art has following advantage:

1. the present invention constitutes a bypass return line by service valve hydraulic fluid port BO is communicated with hydraulic fluid port AO, break-make by solenoid control bypass return line, electromagnetic valve is opened and closed by solenoid control switch control, when engine start, solenoid control switch opens electromagnetic valve provides guide oil by guide's oil pump, guide oil promotes service valve through electromagnetic valve and opens, service valve is communicated with the bypass return line, hydraulic oil bypass oil return is to fuel tank, thereby reduced the pressure loss that flows through choke valve, the pressure step-down of pumping hole, the required power of pump is also lower, so motor with load also light, make to start and to become easily, adapt to the low temp operation environment; Behind the engine start, the solenoid control switch cuts out, and electromagnetic valve turn-offs, oil pump normal fuel injection, excavator normal operation;

2. by the setting of bypass return line, make that the starting load of excavator is alleviated,, can remove the additional all kinds of cold start-up preheating devices of installing simultaneously from, reduce production costs and maintenance cost the power requirement decline of motor;

3. the present invention is simple in structure, and is easy to use, and is easy to realize, is fit to promote the use of.

Description of drawings

Fig. 1 is an electromagnetic valve open mode schematic diagram not in the embodiment of the invention one;

Fig. 2 is a schematic diagram under the electromagnetic valve open mode in the embodiment of the invention one.

Wherein: 1, solenoid control switch; 2, electromagnetic valve; 3, service valve; 4, fuel tank.

The specific embodiment

Below in conjunction with drawings and Examples the present invention is further described:

Embodiment one: shown in Fig. 1,2, a kind of device that reduces starting load of excavator, comprise a solenoid control switch 1 and an electromagnetic valve 2, described electromagnetic valve 2 oil inlet P are connected on the oil-out of guide's oil pump, the delivery outlet A of this electromagnetic valve 2 is connected with the control port X mouth of service valve 3, and the oil return inlet T of described electromagnetic valve is connected on the return line.

Referring to shown in Figure 1, when solenoid control switch 1 is not opened, electromagnetic valve 2 cuts out, when low engine speed starts, because valve core of the electromagnetic valve is not opened, cause not having pilot pressure and promote the service valve unlatching, so engine start moment front pump produces, and flow collaborates valve by scraper bowl and the negative-feedback valve carries out flowing back to fuel tank after the throttling; Back pump produces flow to be undertaken flowing back to fuel tank after the throttling by service valve 3, scraper bowl interflow valve and negative-feedback valve; Owing to cause the oil circuit pressure loss to improve through throttling, motor need overcome the load that the pressure loss produces, cause motor in the winter time low, the hydraulic oil viscosity of temperature start difficulty when big.

Referring to shown in Figure 2, when solenoid control switch 1 was opened, electromagnetic valve 2 was opened, when low engine speed starts, because valve core of the electromagnetic valve is opened, therefore electromagnetic valve output pilot pressure promotes service valve and opens, engine start moment, back pump output hydraulic oil by 3 right of service valves to service valve hydraulic fluid port BO, by outside oil circuit the BO hydraulic fluid port is communicated with service valve AO hydraulic fluid port, return service valve to fuel tank 4 by AO mouth hydraulic oil, therefore back pump hydraulic oil need not directly to flow back to fuel tank by choke valve NR2; Because without crossing throttling, so the oil circuit pressure loss reduces, and motor need not to overcome the load that the pressure loss produces, thereby is easier to start.

Claims

1. control method that reduces starting load of excavator, it is characterized in that: when excavating machine starting, open the solenoid control switch, guide's oil pump output pilot pressure oil promotes service valve from electromagnetic valve A mouth output inflow service valve and opens, and to service valve hydraulic fluid port BO, hydraulic fluid port BO is communicated with formation bypass return line to back pump output hydraulic oil with service valve hydraulic fluid port AO through service valve, hydraulic oil flows back to service valve from hydraulic fluid port AO, flow back to fuel tank again, finish start-up course after, close the solenoid control switch.

2. device that reduces starting load of excavator, it is characterized in that: comprise a solenoid control switch (1) and an electromagnetic valve (2), described electromagnetic valve (2) oil inlet P is connected on the oil-out of guide's oil pump, the delivery outlet A of this electromagnetic valve (2) is connected with the control port X mouth of service valve (3), and the oil return inlet T of described electromagnetic valve is connected on the return line.