CN100392257C - Hydraulic working machine - Google Patents

Abstract

A hydraulic circuit for a hydraulic working machine is composed of a main pump 21 , a boom cylinder 11 arranged for extension or contraction by pressure oil from the main pump 21 , a directional control valve 22 for controlling flows of pressure oil to be fed from the main pump 21 to a bottom chamber 11 a and rod chamber 12 b of the boom cylinder 11 , a control unit 23 for performing a change-over control of the directional control valve 22 , a pilot pump 24 , a jack-up selector valve 25 for controlling a flow of pressure oil delivered from the pilot pump 24 , a flow control valve 26 connected on an upstream side of the directional control valve 22 to a meter-in port of the directional control valve 22 such that the flow control valve 26 can be changed over by the jack-up selector valve 25 , and a center bypass selector valve 27 connected on a downstream side of the directional control valve 22 to a center bypass port of the directional control valve 22 such that the center bypass selector valve 27 can be changed over by the jack-up selector valve 25 . The hydraulic circuit performs a change-over of the jack-up selector valve 25 in accordance with a bottom pressure on the boom cylinder 11.

Description

Hydraulic working machine

Technical field

The present invention relates to hydraulic working machines such as hydraulic shovel, particularly relate to the structure of the oil hydraulic circuit of the cylinder bottom chamber of Pressure oil feeder oil hydraulic cylinder and piston rod chamber with job factors such as dbl act Driven by Hydraulic Cylinder arm, cantilever and scraper bowls.

Background technique

In the past, known hydraulic working machine has, possess the walking states feeler mechanism of the walking states that detects hydraulic shovel and switch to disconnect or be communicated with and transmit the descend switching valve of position of first rodding of pilot signal of (direction that arm dwindles with oil hydraulic cylinder) usefulness of arm according to signal from this walking states feeler mechanism, by when above-mentioned walking state detection mechanism detects walking states, switching above-mentioned switching valve in the position that is communicated with above-mentioned first rodding, handle is used the piston rod chamber of oil hydraulic cylinder from the Pressure oil feeder arm of main pump when walking the composite move of action and arm down maneuver, utilize the hydraulic working machine (for example, opening flat 6-2344 communique (Fig. 1)) that arm can the lifting car body with reference to patent documentation 1 spy.

In addition, also knowing in the past has, when the arm step-down operation, make from arm and regenerate with the piston rod chamber of oil hydraulic cylinder at arm with the oil that returns of the cylinder bottom chamber of oil hydraulic cylinder, to scheme to reduce the consumption power of main pump, and can prevent to be accompanied by and act on the hydraulic working machine (for example, with reference to patent documentation 2 spies open flat 5-302604 communique (Fig. 1)) of arm with the change of the arm movement speed of the variation of the external force of oil hydraulic cylinder etc.

Summary of the invention

Among the above-mentioned prior art, patent documentation 1 described technology since only when walking the composite move of action and arm down maneuver the piston rod chamber of using oil hydraulic cylinder from the Pressure oil feeder arm of main pump, so in the way of simple arm step-down operation when extruding force acts on arm, arm becomes vacuum state and produces the space with the piston rod chamber of oil hydraulic cylinder, has the shortcoming that is easy to arm operation generation action delay.

On the other hand, technology described in the patent documentation 2 is owing to be always the structure of using the piston rod chamber of oil hydraulic cylinder from the Pressure oil feeder arm of main pump when the arm step-down operation, so, concerning the simple arm down maneuver of the extruding force that do not need to be used for the lifting car body, not from the Pressure oil feeder arm of main pump piston rod chamber with oil hydraulic cylinder, have than only make from main pump return oil the regeneration of piston rod chamber the time make pump consumption power become big shortcoming on the contrary.In addition, arm is fallen and when driving other job factors, owing to be supplied to the piston rod chamber of arm, thereby the delivery volume of the pressure oil of the actuator that is used to drive other job factors is reduced relatively, have the shortcoming of energy efficiency variation with oil hydraulic cylinder from the pressure oil of main pump ejection.In addition, when for example when moorland is deviate from or when large slope descends, walking simultaneously, carry out lifting with arm indication italic.

The present invention proposes in order to solve shortcoming of the prior art, its purpose can reduce the consumption power of main pump and improve energy efficiency when being to be provided at simple job factor down maneuver, and can produce the hydraulic working machine of the big extruding force of the lifting power etc. of car body.

In order to achieve the above object, the present invention the 1st is, stretch from the pressure oil of main pump ejection possessing utilization, drive the dbl act oil hydraulic cylinder of job factor, the position control valve of the flow direction of the pressure oil of above-mentioned oil hydraulic cylinder is supplied with in control from above-mentioned main pump, carry out in the hydraulic working machine of operation equipment of handover operation of this position control valve, make it have following feature: to possess, when the supply pressure to above-mentioned oil hydraulic cylinder reaches the regulation pressure, the lifting switching valve that stream is switched, the handover operation of following this switching valve is the stream shifting mechanism that the stream of the pressure oil of inlet restriction (meter in) supply of above-mentioned position control valve is altered to open circuit side or closed circuit side from above-mentioned main pump, when above-mentioned job factor down maneuver, the maintenance of above-mentioned oil hydraulic cylinder is pressed in afore mentioned rules and presses when above, above-mentioned lifting switching valve is switched to the 1st switching position, above-mentioned stream shifting mechanism is switched to closed circuit side, supply side is not pressed in the non-maintenance of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from above-mentioned main pump, when above-mentioned job factor down maneuver, when the maintenance pressure of above-mentioned oil hydraulic cylinder does not arrive the afore mentioned rules pressure, above-mentioned lifting switching valve is switched to the 2nd switching position, above-mentioned stream shifting mechanism is switched to the open circuit side, side is pressed in the maintenance of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from above-mentioned main pump through above-mentioned position control valve.

In addition, in order to achieve the above object, the present invention the 2nd is, possessing main pump, job factor, utilization is stretched from the pressure oil of above-mentioned main pump ejection, drive the dbl act oil hydraulic cylinder of above-mentioned job factor, the position control valve of the flow direction of the pressure oil of the cylinder bottom chamber of above-mentioned oil hydraulic cylinder and piston rod chamber is supplied with in control from above-mentioned main pump, carry out in the hydraulic working machine of operation equipment of handover operation of this position control valve, make it have following structure: to possess, cylinder bottom pressure at above-mentioned oil hydraulic cylinder reaches the lifting switching valve that switches when regulation is pressed, the handover operation that is accompanied by this lifting switching valve is the stream shifting mechanism that the stream of the pressure oil of the inlet restriction supply of above-mentioned position control valve is transformed to open circuit side or closed circuit side from above-mentioned main pump, the cylinder bottom of above-mentioned oil hydraulic cylinder is pressed in afore mentioned rules and presses when above when above-mentioned job factor down maneuver, above-mentioned lifting switching valve is switched to the 1st switching position and makes above-mentioned stream shifting mechanism switch to closed circuit side, not the piston rod chamber of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from above-mentioned main pump, the cylinder bottom of above-mentioned oil hydraulic cylinder is pressed in afore mentioned rules and presses when following when above-mentioned job factor down maneuver, above-mentioned lifting switching valve is switched to the 2nd switching position and makes above-mentioned stream shifting mechanism switch to the open circuit side, and the above-mentioned position control valve of process is the piston rod chamber of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from above-mentioned main pump.

For example, at the state that external force does not act on, bearing as the weight of the arm of job factor or cantilever etc. and making cylinder bottom chamber side is high pressure to the arm that is located at hydraulic shovel with oil hydraulic cylinder.To this, when extruding force acted on job factor, tensile force acted on the arm oil hydraulic cylinder, and the cylinder bottom chamber of oil hydraulic cylinder is a low pressure.Therefore, monitor the variation that this cylinder bottom is pressed, the cylinder bottom that drives the oil hydraulic cylinder of this job factor when the job factor down maneuver is pressed in regulation and presses when above, the lifting switching valve is switched to the 1st switching position and makes the stream shifting mechanism switch to closed circuit side, not the words of the piston rod chamber of the Pressure oil feeder oil hydraulic cylinder that sprays from main pump, pump consumption power in the time of can reducing the down maneuver of simple job factor of the extruding force that does not need to be used to make the car body lifting, and, when making a job factor fall and make other job factor composite moves, owing to can increase the pressure oil of supplying with the actuator be used to drive other job factors from main pump relatively, thereby can improve the energy efficiency of hydraulic working machine.In addition, the cylinder bottom of oil hydraulic cylinder is pressed in regulation and presses when following when the job factor down maneuver, the lifting switching valve is switched to the 2nd switching position and makes the stream shifting mechanism switch to the open circuit side, the process position control valve is the words of the piston rod chamber of the Pressure oil feeder oil hydraulic cylinder that sprays from main pump, owing to can produce very big extruding force to job factor, thereby make the lifting of car body become possibility.

In addition, in order to achieve the above object, the present invention the 3rd is, possessing the 1st and the 2nd main pump, the 1st traveling gear that the pressure oil that is sprayed from above-mentioned the 1st main pump drives, the 2nd traveling gear that the pressure oil that is sprayed from above-mentioned the 2nd main pump drives, the 1st position control valve of the flow direction of the pressure oil of above-mentioned the 1st traveling gear is supplied with in control from above-mentioned the 1st main pump, the 2nd position control valve of the flow direction of the pressure oil of above-mentioned the 2nd traveling gear is supplied with in control from above-mentioned the 2nd main pump, job factor, utilization is stretched from the pressure oil of the above-mentioned the 1st and the 2nd main pump ejection, drive the dbl act oil hydraulic cylinder of above-mentioned job factor, the 3rd position control valve of the flow direction of the pressure oil of the cylinder bottom chamber of above-mentioned oil hydraulic cylinder and piston rod chamber is supplied with in control from above-mentioned the 1st main pump, the 4th position control valve of the flow direction of the pressure oil of the cylinder bottom chamber of above-mentioned oil hydraulic cylinder and piston rod chamber is supplied with in control from above-mentioned the 2nd main pump, carry out the above-mentioned the 1st and the 1st operation equipment of the handover operation of the 2nd position control valve, carry out the above-mentioned the 3rd and the hydraulic working machine of the 2nd operation equipment of the handover operation of the 4th position control valve in, make it have following structure: to possess, cylinder bottom pressure at above-mentioned oil hydraulic cylinder reaches the lifting switching valve that switches when regulation is pressed, the handover operation that is accompanied by this lifting switching valve is the stream shifting mechanism that the stream of the pressure oil of the inlet restriction supply of above-mentioned the 3rd position control valve is transformed to open circuit side or closed circuit side from above-mentioned the 1st main pump, the cylinder bottom of above-mentioned oil hydraulic cylinder is pressed in afore mentioned rules and presses when above when above-mentioned job factor down maneuver, above-mentioned lifting switching valve is switched to the 1st switching position and makes above-mentioned stream shifting mechanism switch to closed circuit side, not the piston rod chamber of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from the above-mentioned the 1st and the 2nd main pump, the cylinder bottom of above-mentioned oil hydraulic cylinder is pressed in afore mentioned rules and presses when following when above-mentioned job factor down maneuver, above-mentioned lifting switching valve is switched to the 2nd switching position and makes above-mentioned stream shifting mechanism switch to the open circuit side, and process the above-mentioned the 3rd and the 4th position control valve is the piston rod chamber of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from the above-mentioned the 1st and the 2nd main pump.

In this structure, also performance and the same effect of above-mentioned the 2nd problem solution, the consumption power of pump and improve the energy efficiency of hydraulic working machine in the time of can reducing simple job factor down maneuver, and, can produce very big extruding force to job factor.In addition, owing to possess the oil hydraulic circuit of walking usefulness, thus by the action and the composite move of job factor down maneuver of walking, make the lifting of car body become possibility.

In addition, in order to achieve the above object, the present invention the 4th is, the above-mentioned the 1st or the hydraulic working machine of the 2nd structure in, make it have following structure: to possess the regenerative circuit of inlet restriction oil of a part of regeneration of the outlet throttling oil of discharging from the cylinder bottom chamber of above-mentioned oil hydraulic cylinder being supplied with the piston rod chamber of above-mentioned oil hydraulic cylinder.

Like this, the words that possess regenerative circuit, when extruding force acts on job factor in the step-down operation way of simple job factor, owing to be supplied to the piston rod chamber of oil hydraulic cylinder from the recovered oil of cylinder bottom chamber, the piston rod chamber of oil hydraulic cylinder becomes vacuum state can not produce the space, can keep the quiet run of job factor yet.

In addition, in order to achieve the above object, in the hydraulic working machine of above-mentioned each structure, make it have following structure: to possess hydraulic pilot formula switching valve as above-mentioned lifting switching valve.

Like this, possess the words of hydraulic pilot formula switching valve as above-mentioned lifting switching valve, only the cylinder bottom chamber of the signal port of lifting switching valve and oil hydraulic cylinder is coupled together and get final product with oil duct, because it is simple in structure, the consumption power of pump and improve the energy efficiency of hydraulic working machine in the time of can reducing simple job factor down maneuver, can implement at an easy rate can the lifting car body hydraulic working machine.

In order to achieve the above object, the present invention the 5th is, at the variable capacity type oil hydraulic pump that possesses as main pump, control the control mechanism that verts of above-mentioned variable capacity type hydraulic pressure pump delivery, at least one job factor, utilization is stretched from the pressure oil of above-mentioned variable capacity type oil hydraulic pump ejection, drive at least one actuator of above-mentioned job factor, the position control valve of the flow direction of the pressure oil of above-mentioned oil hydraulic cylinder is supplied with in control from above-mentioned variable capacity type oil hydraulic pump, control the pilot operated device of the amount of movement of above-mentioned position control valve, according to from the signal of pilot operated device in the hydraulic working machine of the indicating device of verting of the above-mentioned control mechanism output tilt control signal that verts, make it have following structure: to possess, maintenance pressure in above-mentioned actuator reaches the lifting switching valve that switches when regulation is pressed, the handover operation that is accompanied by this lifting switching valve is the stream shifting mechanism that the stream of the pressure oil of the inlet restriction supply of above-mentioned position control valve is transformed to open circuit side or closed circuit side from above-mentioned variable capacity type oil hydraulic pump, the maintenance of above-mentioned actuator is pressed in afore mentioned rules and presses when above when the decline of above-mentioned job factor, above-mentioned lifting switching valve is switched to the 1st switching position and makes above-mentioned stream shifting mechanism switch to closed circuit side, the pressure oil of above-mentioned actuator is supplied with in disconnection from above-mentioned variable capacity type oil hydraulic pump, and, control reduces above-mentioned variable capacity type hydraulic pressure pump delivery, the maintenance of above-mentioned actuator is pressed in afore mentioned rules and presses when following when above-mentioned job factor down maneuver, above-mentioned lifting switching valve is switched to the 2nd switching position and makes above-mentioned stream shifting mechanism switch to the open circuit side, the above-mentioned position control valve of process is the above-mentioned actuator of Pressure oil feeder from above-mentioned variable capacity type oil hydraulic pump ejection, and, utilize the above-mentioned indicating device's control of verting to increase above-mentioned variable capacity type hydraulic pressure pump delivery.

For example, at the state that external force does not act on, bearing as the weight of the arm of job factor or cantilever etc. and making cylinder bottom chamber side is high pressure to the arm that is located at hydraulic shovel with oil hydraulic cylinder.To this, when extruding force acted on job factor, tensile force acted on the arm oil hydraulic cylinder, thereby the cylinder bottom chamber is a low pressure.Therefore, the variation that the maintenance of the actuator of the cylinder bottom pressure of supervision arm usefulness oil hydraulic cylinder etc. is pressed, the maintenance that drives the actuator of this job factor when the job factor down maneuver is pressed in regulation and presses when above, the lifting switching valve is switched to the 1st switching position and makes the stream shifting mechanism switch to closed circuit side, not the words of the Pressure oil feeder actuator that sprays from variable capacity hydraulic pump as main pump, the consumption power of the pump in the time of can reducing the decline of simple job factor of the extruding force that does not need to be used to make the car body lifting, and, when making a job factor fall and make other job factor composite moves, owing to can increase the pressure oil of supplying with the actuator be used to drive other job factors from main pump relatively, thereby can improve the energy efficiency of hydraulic working machine.In addition, the maintenance of actuator is pressed in regulation and presses when following when the job factor down maneuver, the lifting switching valve is switched to the 2nd switching position and makes the stream shifting mechanism switch to the open circuit side, the process position control valve is the words of the Pressure oil feeder actuator that sprays from the variable capacity hydraulic pump as main pump, owing to can produce very big extruding force to job factor, thereby make the lifting of car body become possibility.Have again, the maintenance that drives the actuator of this job factor when the job factor down maneuver is pressed in regulation and presses when above, control reduces variable capacity type hydraulic pressure pump delivery, the maintenance of actuator is pressed in regulation and presses the words of utilizing the indicating device's control increase variable capacity type hydraulic pressure pump delivery that verts when following when the job factor down maneuver, the consumption power of pump in the time of can reducing the decline of simple job factor, can reduce the fuel cost of hydraulic working machine, and, because can be when the squeeze job of job factor, thereby can successfully carry out change from the down maneuver of simple job factor to the squeeze job of job factor promptly the Pressure oil feeder actuator of necessary amount.

In addition, in order to achieve the above object.The present invention the 6th is, at the 1st and the 2nd variable capacity type oil hydraulic pump that possesses as main pump, control the 1st and the 2nd of the above-mentioned the 1st and the 2nd variable capacity type hydraulic pressure pump delivery control mechanism that verts respectively, the 1st traveling gear that the pressure oil that is sprayed from above-mentioned the 1st variable capacity type oil hydraulic pump drives, the 2nd traveling gear that the pressure oil that is sprayed from above-mentioned the 2nd variable capacity type oil hydraulic pump drives, the 1st position control valve of the flow direction of the pressure oil of above-mentioned the 1st traveling gear is supplied with in control from above-mentioned the 1st variable capacity type oil hydraulic pump, the 2nd position control valve of the flow direction of the pressure oil of above-mentioned the 2nd traveling gear is supplied with in control from above-mentioned the 2nd variable capacity type oil hydraulic pump, at least one job factor, utilization is stretched from the pressure oil of the above-mentioned the 1st and the 2nd variable capacity type oil hydraulic pump ejection, drive at least one actuator of above-mentioned job factor, the 3rd position control valve of the flow direction of the pressure oil of above-mentioned actuator is supplied with in control from above-mentioned the 1st variable capacity type oil hydraulic pump, the 4th position control valve of the flow direction of the pressure oil of above-mentioned actuator is supplied with in control from above-mentioned the 2nd variable capacity type oil hydraulic pump, carry out the above-mentioned the 1st and the pilot operated device of the handover operation of the 2nd position control valve, according to from the signal of above-mentioned pilot operated device in the hydraulic working machine of the indicating device of verting of the above-mentioned control rotation mechanism output tilt control signal that inclines, make it have following structure: to possess, maintenance pressure in above-mentioned actuator reaches the lifting switching valve that switches when regulation is pressed, the handover operation that is accompanied by this lifting switching valve transforms to the pressure oil stream of the inlet restriction of above-mentioned the 3rd position control valve being supplied with from above-mentioned the 1st variable capacity type oil hydraulic pump the stream shifting mechanism of open circuit side or closed circuit side, when the down maneuver of above-mentioned job factor, being pressed in afore mentioned rules in the maintenance of above-mentioned actuator presses when above, above-mentioned lifting switching valve is switched to the 1st switching position and make above-mentioned stream shifting mechanism switch to closed circuit side, the pressure oil of above-mentioned actuator is supplied with in disconnection from the above-mentioned the 1st and the 2nd variable capacity type oil hydraulic pump, and control reduces by the above-mentioned the 1st and the 2nd variable capacity type hydraulic pressure pump delivery, when the decline of above-mentioned job factor, the maintenance of above-mentioned actuator is pressed in afore mentioned rules and presses when following, above-mentioned lifting switching valve is switched to the 2nd switching position and above-mentioned stream shifting mechanism is switched to the open circuit side, through the above-mentioned the 3rd and the 4th position control valve the above-mentioned actuator of Pressure oil feeder from the ejection of the above-mentioned the 1st and the 2nd variable capacity type oil hydraulic pump, and, utilize the above-mentioned indicating device's control of verting to increase by the above-mentioned the 1st and the 2nd variable capacity type hydraulic pressure pump delivery.

In this structure, brought into play and the same effect of above-mentioned the 2nd problem solution, the energy efficiency of the consumption power of pump and raising hydraulic working machine in the time of can reducing simple job factor down maneuver, and can produce very big extruding force to job factor, and, can successfully carry out change from the down maneuver of simple job factor to the squeeze job of job factor.In addition, owing to possess the oil hydraulic circuit of walking usefulness, thus by the action and the composite move of job factor down maneuver of walking, make the lifting of car body become possibility.

In addition, in order to achieve the above object, the present invention the 7th is, in the hydraulic working machine of above-mentioned the 1st, the 2nd or the 5th structure, make it have following structure: above-mentioned stream shifting mechanism is by constituting with lower member: the upstream side at position control valve is connected with the inlet restriction mouth of this position control valve, switch to closed circuit position when above-mentioned lifting switching valve switches to the 1st switching position, switch to the flow control valve of open-circuit position when above-mentioned lifting switching valve switches to the 2nd switching position; Downstream side at position control valve is connected with the center by-pass flow mouth of this position control valve, switch to the open-circuit position when above-mentioned lifting switching valve switches to the 1st switching position, switch to the center by-pass flow switching valve of closed circuit position when above-mentioned lifting switching valve switches to the 2nd switching position.

Like this, constitute the 1st by the flow control valve and the center by-pass flow switching valve that switch according to the switching position of lifting switching valve, the the 2nd or the 5th problem solves the words of the stream shifting mechanism in the mechanism, when lifting switching valve to the 1 switching position, the i.e. occasion that falls because of deadweight at job factor, because flow control valve is switched to closed circuit position, and center by-pass flow switching valve is switched to the open-circuit position, so, return the pressure fuel tank from the pressure oil of main pump ejection through the center by-pass flow mouth and the center by-pass flow switching valve of position control valve, the supply of the pressure oil of the piston rod chamber of oil hydraulic cylinder is stopped.In addition, when the lifting switching valve is switched to the 2nd switching position, be that extruding force is when affacting job factor, because flow control valve is switched to the open-circuit position, and, center by-pass flow switching valve is switched to closed circuit position, so, be supplied to the piston rod chamber of oil hydraulic cylinder through the inlet restriction mouth of flow control valve and position control valve from the pressure oil of main pump ejection.Therefore, the consumption power of pump and improve the energy efficiency of hydraulic working machine in the time of can reducing simple job factor down maneuver, and, can produce very big extruding force to job factor, make the lifting of car body become possibility.

In addition, in order to achieve the above object, the present invention the 8th is, the above-mentioned the 3rd or the hydraulic working machine of the 6th structure in, make it have following structure: above-mentioned stream shifting mechanism is by constituting with lower member: the upstream side at above-mentioned the 3rd position control valve is connected with the inlet restriction mouth of the 3rd position control valve, switch to closed circuit position when above-mentioned lifting switching valve switches to the 1st switching position, switch to the flow control valve of open-circuit position when above-mentioned lifting switching valve switches to the 2nd switching position; Downstream side at above-mentioned the 3rd position control valve is connected with the center by-pass flow mouth of above-mentioned the 3rd position control valve, switch to the open-circuit position when above-mentioned lifting switching valve switches to the 1st switching position, switch to the center by-pass flow switching valve of closed circuit position when above-mentioned lifting switching valve switches to the 2nd switching position.

In this structure, brought into play and the same effect of above-mentioned the 3rd problem solution, the consumption power of pump and improve the energy efficiency of hydraulic working machine when reducing simple job factor down maneuver, and, walk the composite move of the down maneuver of action and job factor by carrying out the heart, make the lifting of car body become possibility.

In addition, in order to achieve the above object, the present invention the 9th is, in the hydraulic working machine of above-mentioned the 7th to the 9th structure, make it have following structure: to possess hydraulic pilot formula switching valve as above-mentioned lifting switching valve, on the pilot port of this hydraulic pilot formula switching valve, possess throttling.

Like this, possess the words of the switching valve of hydraulic pressure guiding as the lifting switching valve, only get final product with the signal port of oil duct connection lifting switching valve and the cylinder bottom chamber of oil hydraulic cylinder, because it is simple in structure, thereby the consumption power of pump and improve energy efficiency in the time of can reducing simple arm and descend, can implement at an easy rate can the lifting car body hydraulic working machine.In addition, possess throttling, can prevent the swing of hydraulic pilot formula switching valve in the pilot port of oil pressure leading type switching valve, can be smoothly and carry out change reliably from the down maneuver of simple job factor to the squeeze job of job factor.

In addition, in order to achieve the above object, the present invention the 10th is, in the hydraulic working machine of above-mentioned the 1st to the 9th structure, adopt following structure, also be provided with: control the electromagnetic type switching valve of the switch motion of above-mentioned lifting switching valve, detect the Pressure testing mechanism of force value of the cylinder bottom chamber of above-mentioned oil hydraulic cylinder, based on utilizing the detected pressure of above-mentioned Pressure testing mechanism to make the electric control mechanism of above-mentioned electromagnetic type switching valve action.

Like this, possess the electromagnetic type switching valve as the lifting switching valve, owing to can omit the oil duct of the signal port of the cylinder bottom chamber (keeping pressing side) that connects oil hydraulic cylinder and lifting switching valve at least, so, can simplify oil hydraulic circuit.

In addition, in order to achieve the above object, the present invention the 11st is, the above-mentioned the 5th or the hydraulic working machine of the 6th structure in, make it have following structure: the above-mentioned indicating device of verting is constituting by a plurality of shuttle valves of the maximum pressure of the operation signal pressure group of selecting regulation among the operation signal pressure that utilizes above-mentioned pilot operated device to produce.

Like this, use the words of the combination of a plurality of shuttle valves as the indicating device of verting, owing to can select desired operation signal pressure really with simple loop structure, so, utilize the indicating device's control of verting to increase the hydraulic working machine of variable capacity type hydraulic pressure pump delivery in the time of can being implemented in the squeeze job of job factor at an easy rate.In addition, utilize this indicating device of verting to select the words of maximum pressure among the predetermined operation signal pressure group, because can be positively the Pressure oil feeder actuator of necessary amount when the squeeze job of job factor, so, can be smoothly and carry out change reliably from the down maneuver of simple job factor to the squeeze job of job factor.

In addition, in order to achieve the above object, the present invention the 12nd is, in the hydraulic working machine of above-mentioned each structure, make it have following structure: the job factor that carries out above-mentioned down maneuver is an arm, and above-mentioned actuator is the arm oil hydraulic cylinder.

Like this, possesses arm as above-mentioned job factor, possess arm and use oil hydraulic cylinder,, brought into play at the above-mentioned the 5th and the 6th described action effect of problem solution concerning possessing arm and arm with the hydraulic working machines such as hydraulic shovel of oil hydraulic cylinder as above-mentioned actuator.

In addition, in order to achieve the above object, the present invention the 13rd is, in the hydraulic working machine of structure, make it have following structure: to possess supplying with the regenerative circuit of above-mentioned arm with a part of regeneration of the outlet throttling oil of the cylinder bottom chamber discharge of oil hydraulic cylinder with the inlet restriction oil of the piston rod chamber of oil hydraulic cylinder from above-mentioned arm the above-mentioned the 12nd.

Like this, the words that possess regenerative circuit, when extruding force acts on arm in the way of the step-down operation of simple job factor, because the recovered oil from the cylinder bottom chamber is supplied to the piston rod chamber of arm with oil hydraulic cylinder, so, arm becomes vacuum state and can not produce the space with the piston rod chamber of oil hydraulic cylinder, can keep the operation smoothly of arm.

In addition, here so-called regulation is pressed above and is not arrived regulation and press, because be expression being benchmark with the regulation pressure presses the different occasions of big occasion and little occasion than regulation, so, make the switching position of the lifting switching valve of the occasion that regulation presses be the 1st switching position or be the 2nd switching position, the item of the design of when design, suitably setting.

Like this, possess the words of hydraulic pilot formula switching valve as the lifting switching valve, because as long as oil duct connects the cylinder bottom chamber of oil hydraulic cylinder and the signal port of lifting switching valve, can simplified structure, so the consumption power of pump and improve the energy efficiency of hydraulic working machine in the time of can reducing simple job factor down maneuver makes the lifting of car body become possibility.

Like this, possess the electromagnetic type switching valve as the lifting switching valve, owing to can omit the oil duct of the signal port of the cylinder bottom chamber that links oil hydraulic cylinder and lifting switching valve at least, so can simplify oil hydraulic circuit.

As mentioned above, hydraulic working machine of the present invention, monitor the variation of the cylinder bottom pressure of the oil hydraulic cylinder that drives job factor, because when the job factor down maneuver, the cylinder bottom that drives the oil hydraulic cylinder of this job factor is pressed in regulation and presses when above, make the stream shifting mechanism switch to closed circuit side owing to the lifting switching valve being switched to the 1st switching position, not the piston rod chamber of the Pressure oil feeder oil hydraulic cylinder that sprays from main pump, so consumption power of the pump in the time of can reducing the decline of simple job factor of the extruding force that needn't be used to make the car body lifting, and, when making a job factor fall and make other job factor composite moves, owing to can increase the pressure oil of supplying with the actuator be used to drive other job factors from main pump relatively, thereby can improve the energy efficiency of hydraulic working machine.In addition, when the cylinder bottom of oil hydraulic cylinder is pressed not to the regulation pressure when the job factor down maneuver, make the stream shifting mechanism switch to the open circuit side owing to the lifting switching valve being switched to the 2nd switching position, the process position control valve is the piston rod chamber of the Pressure oil feeder oil hydraulic cylinder that sprays from main pump, so can produce the driving force of the necessary job factor of lifting of car body, the composite move by the walk action and the down maneuver of job factor makes the lifting of car body become possibility.

Description of drawings

Fig. 1 is the side view of hydraulic working machine of the present invention.

Fig. 2 is the circuit diagram of the 1st embodiment's oil hydraulic circuit.

Fig. 3 is the pie graph of operation equipment.

Fig. 4 is the circuit diagram of the oil hydraulic circuit of the 2nd mode of execution.

Fig. 5 is the circuit diagram of the oil hydraulic circuit of the 3rd mode of execution.

Fig. 6 is the circuit diagram of the oil hydraulic circuit of the 4th mode of execution.

Fig. 7 is the circuit diagram of the oil hydraulic circuit of the 5th mode of execution.

Fig. 8 is the circuit diagram of the oil hydraulic circuit of the 6th mode of execution.

Fig. 9 is the circuit diagram of major component of showing the oil hydraulic circuit of the 6th mode of execution.

Figure 10 is the circuit diagram of the oil hydraulic circuit of the 7th mode of execution.

Figure 11 is the circuit diagram of the oil hydraulic circuit of the 8th mode of execution.

Figure 12 is the circuit diagram of the oil hydraulic circuit of the 9th mode of execution.

Figure 13 is the circuit diagram of the oil hydraulic circuit of the 10th mode of execution.

Figure 14 is the structural drawing of the shuttle valve group that oil hydraulic circuit possessed of the 10th mode of execution.

Embodiment

(surface structure of hydraulic working machine)

The surface structure of hydraulic working machine of the present invention at first, is described with Fig. 1.Fig. 1 is the side view of hydraulic working machine of the present invention.

This routine hydraulic working machine is a hydraulic shovel, as shown in Figure 1, it is mainly by constituting with lower member, by pairing left and right traveling gear 1,2 runneies of forming 3, rotation is installed in the solid of rotation 4 on this runner 3 freely, the arm 5 that one end combines with solid of rotation 4 freely with the pin rotation, the cantilever 6 that one end combines with arm 5 freely with the pin rotation, the scraper bowl 7 that one end combines with cantilever 6 freely with the pin rotation, drive traveling gear 1,2 the 1st and the 2nd walking fluid pressure motor 8,9, the rotation of rotary driving body 4 fluid pressure motor 10, drive the arm oil hydraulic cylinder 11 of arm 5, drive the cantilever oil hydraulic cylinder 12 of cantilever 6, drive the scraper bowl oil hydraulic cylinder 13 of scraper bowl 7.

(the 1st example of oil hydraulic circuit)

Secondly, the 1st example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Fig. 2 and Fig. 3.Fig. 2 is the circuit diagram of major component of the 1st embodiment's oil hydraulic circuit, Fig. 3 is the structural drawing of operation equipment, and from these figure as can be known, this routine oil hydraulic circuit is characterised in that, possess hydraulic pilot formula switching valve as the lifting switching valve, and will be from the Pressure oil feeder oil hydraulic cylinder of a main pump.

As shown in Figure 2, this routine oil hydraulic circuit is mainly by constitute main pump 21 with lower member, utilization is stretched from the pressure oil of main pump 21 ejection, drive the dbl act arm oil hydraulic cylinder 11 of arm 5, control is supplied with the position control valve 22 of arms with the flow direction of the pressure oil of the cylinder bottom chamber 11a of oil hydraulic cylinders 11 and piston rod chamber 11b from main pump 21, the operation equipment 23 of the handover operation of travel direction control valve 22, pioneer pump 24, control is from the lifting switching valve 25 of the flow direction of the pressure oil of pioneer pump 24 ejections, upstream side at position control valve 22 is connected with the inlet restriction mouth of position control valve 22, utilize lifting switching valve 25 to carry out the flow control valve 26 of handover operation, downstream side at position control valve 22 is connected with the center by-pass flow mouth of position control valve 22, utilize lifting switching valve 25 to carry out the center by-pass flow switching valve 27 of handover operation, fuel tank 28.In addition, lifting switching valve 25 is to be communicated with the inlet restriction side and the hydraulic pilot formula switching valve that switches in order to make from the pressure oil of main pump 21 ejection when carrying out lifting, and center by-pass flow switching valve 27 is the switching valves that are used to open and close the center by-pass flow.

In addition, flow control valve 26 is made up of the leading type switching valve 262 of the pumping hole side of poppet valve 261 and connection, the back pressure chamber that disconnects this poppet valve 261 and position control valve 22.

Above-mentioned position control valve 22 possesses the regenerative circuit of being made up of throttling 29a, 29b and one-way valve 29c.

In addition, as shown in Figure 3, aforesaid operations device 23 rises side reduction valve 23c by operating stem 23a, the arm decline side reduction valve 23b, arm that utilize this operating stem 23a to carry out handover operation and constitutes.

Between main pump 21 and position control valve 22, be provided with the oil ducts 31 that directly are communicated with from main pump 21 and pass through the oil duct 32,33 that flow control valves 26 are communicated with the inlet restriction mouth of position control valve 22, between position control valve 22 and arm are with oil hydraulic cylinder 11, be provided with oil duct 34 that is communicated with cylinder bottom chamber 11a and the oil duct 35 that is communicated with piston rod chamber 11b from main pump 21 with the center by-pass flow mouth of position control valve 22.In addition, being provided with cylinder bottom between the signal port of arm with the cylinder bottom chamber 11a of oil hydraulic cylinder 11 and lifting switching valve 25 presses signal to supply with oil duct 36.Have again, the oil duct of connecting direction control valve 22 and fuel tank 28 is divided into the oil duct 37 of position control valve 22 sides and the oil duct 38 of fuel tank 28 sides through center by-pass flow switching valve 27, is provided with the oil duct 39 that is used for the part of the pressure oil of discharging from cylinder bottom chamber 11a guiding fuel tank 28 between the oil duct 38 of position control valve 22 and fuel tank 28 sides.In addition, between the signal port of operation equipment 23 and position control valve 22, be provided with the arm dropping signal and supply with the first rodding 40 and the arm rising signals of usefulness and supply with, and be provided with through lifting switching valve 25 arm is descended with the switching signal supply of first pilot guiding centre by-pass flow switching valve 27 with first rodding 42,43 with first rodding 41.In addition, at pioneer pump 24 with constitute to be provided with through the switching signal of lifting switching valve 25 between the signal port of switching valve 262 of flow control valve 26 and supply with first rodding 44,45.

Below, the action of above-mentioned such the 1st embodiment's who constitutes hydraulic working machine is described.

Operating stem 23a is in the neutral position, as shown in Figure 2, when tensile force does not act on arm with oil hydraulic cylinder 11, position control valve 22 is at neutral position 22b, arm with the cylinder bottom chamber 11a of oil hydraulic cylinder 1 owing to the deadweight of supporting arm etc. becomes high pressure, lifting switching valve 25 switches to switching position 25a, and the switching valve 262 of flow control valve 26 switches to switching position 26a, center by-pass flow switching valve 27 maintaining valve position 27a.Therefore, be directed to fuel tank 28 from the pressure oil of main pump 21 ejection center by-pass flow mouth, oil duct 37, center by-pass flow switching valve 27 and the oil duct 38 by oil duct 31, position control valve 22.

From this state to illustrated left ten thousand, promptly to the words of arm descent direction operating operation bar 23a, the pressure oil of supplying with from pioneer pump 24 is depressurized valve 23b decompression, this first pilot that is depressurized exports to first rodding 40 as the arm dropping signal, and position control valve 22 is switched to switching position 22a.And, regenerate at piston rod chamber 11b through throttling 29b, one-way valve 29c and oil duct 35 from the part of returning oil of cylinder bottom chamber 11a, and the remaining oil that returns is returned fuel tank 28 by throttling 29a and oil duct 39.

In this occasion, when the regulation switch pressure that is set by the spring 25c of lifting switching valve 25 in the cylinder bottom pressure ratio is higher, because the switching position of lifting switching valve 25 maintains switching position 25a, so the switching position of flow control valve 26 also maintains switching position 26a, in addition, center by-pass flow switching valve 27 also maintains valve position 27a.Therefore, be directed to fuel tank 28 from the pressure oil of main pump 21 ejection through center by-pass flow mouth, oil duct 37, center by-pass flow switching valve 27 and the oil duct 38 of oil channel 31, position control valve 22, owing to press oil not to be supplied to cylinder bottom chamber 11a and the piston rod chamber 11b of arm with oil hydraulic cylinder 11, thereby have only recovered oil to be directed to piston rod chamber 11b, deadweight because of arm 5, arm dwindles with oil hydraulic cylinder 11, and arm 5 is to descent direction rotation (so-called deadweight falls).

On the other hand, at operating stem 23a to the operated occasion of arm descent direction, when the switch pressure of cylinder bottom pressure ratio lifting switching valve 25 is lower, lifting switching valve 25 is switched to switching position 25b, owing to the pressure oil from pioneer pump 24 of the signal port of the switching valve 262 that is supplied to flow control valve 26 through first rodding 44 and first rodding 45 is disconnected, so switching valve 262 is switched to valve position 26b, the back pressure of poppet valve 261 is identical with pipeline 33 pressure, from the pressure oil of main pump 21 ejection through oil channel 32, the poppet valve 261 of flow control valve 26, oil duct 33 is supplied to the inlet restriction mouth of position control valve 22.In addition, be accompanied by the switching of lifting switching valve 25, be supplied to the signal port of center by-pass flow switching valve 27 through first rodding 40, first rodding 42, lifting switching valve 25, first rodding 43 owing to pressure oil from pioneer pump 24 ejections, so center by-pass flow switching valve 27 is switched to switching position 27b, the downstream of the center by-pass flow of position control valve 22 is disconnected.Therefore, the pressure oil from main pump 21 of the inlet restriction mouth by oil duct 33 feeding direction control valves 22 is supplied to the piston rod chamber 11b of arm with oil hydraulic cylinder 11 with the recovered oil of discharging from cylinder bottom chamber 11a by oil duct 35, can produce the strong extruding forces such as lifting power of car body.

In addition, right-hand to diagram at operating stem 23a, i.e. the occasion of arm ascent direction operation is utilized the pressure oil of supplying with from pioneer pump 24, and arm rises and exports to first rodding 41 with first pilot, and position control valve 22 is switched to switching position 22c.Like this, because the pressure oil of discharging from piston rod chamber 11b returns fuel tank 28 by oil duct 35, position control valve 22, oil duct 39, so it is compared with the lower pressure of the working pressure of heavy switching valve 25 that cylinder bottom is pressed, lifting switching valve 25 is switched to switching position 25b, and flow control valve 26 switches to switching position 26b.Therefore, the pressure oil of main pump 21 that is supplied to the inlet restriction mouth of position control valve 22 through oil channel 32, flow control valve 26, oil duct 33 is supplied to cylinder bottom chamber 11a by oil duct 34, and arm stretches with oil hydraulic cylinder 11, and arm 5 rotates to ascent direction.

The hydraulic working machine of present embodiment monitors the variation that arm is pressed with the cylinder bottom of oil hydraulic cylinder 11, arm is pressed in regulation with the cylinder bottom of oil hydraulic cylinder 11 and presses when above when the arm down maneuver, lifting switching valve 25 is switched to switching position 25a, like this, the switching valve 262 of flow control valve 26 is switched to switching position 26a, and make center by-pass flow valve 27 be valve position 27a, because not from the Pressure oil feeder arm of main pump 21 ejection piston rod chamber 11b, so the consumption power of pump can be reduced in the simple arm down maneuver of the extruding force that do not need to be used for the lifting car body time with oil hydraulic cylinder 11.In addition, since when simple arm down maneuver from the Pressure oil feeder arm of main pump 21 ejections piston rod chamber 11b with oil hydraulic cylinder 11, thereby make arm 5 and other job factors for example when cantilever 6 or scraper bowl 7 composite moves, can make and supply with cantilever from main pump and increase over the ground, can improve the energy efficiency of hydraulic working machine with oil hydraulic cylinder 12 or scraper bowl pressure oil phase with oil hydraulic cylinder 13.On the other hand, arm is pressed in regulation with the cylinder bottom of oil hydraulic cylinder 11 and presses when following when the arm down maneuver, lifting switching valve 25 is switched to valve position 25b, like this, the switching valve 262 of flow control valve 26 is switched to switching position 26b, and center by-pass flow switching valve 27 is switched to switching position 27b, because the piston rod chamber 11b that uses oil hydraulic cylinder 11 from the Pressure oil feeder arm of main pump 21 ejections, thereby can produce very big extruding force to arm 5, make the lifting of car body become possibility.

In addition, the hydraulic working machine of present embodiment, because with possessing the control valve of the regenerative circuit of forming by throttling 29a, 29b, one-way valve 29c as position control valve 22, so when extruding force acts on arm 5 in simple arm step-down operation way, for the recovered oil from cylinder bottom chamber 11a is supplied with the piston rod chamber 11b that arm is used oil hydraulic cylinder 11, arm becomes vacuum state with the piston rod chamber 11b of oil hydraulic cylinder 11 can not produce the space yet, can keep the operation stably of arm 5.

In addition, the hydraulic working machine of present embodiment is owing to possess hydraulic pilot formula switching valve as lifting switching valve 25, get final product so only the signal port of lifting switching valve 25 and arm are coupled together with the cylinder bottom chamber 11a of oil hydraulic cylinder 11 with oil duct 36, simple structure, the consumption power of pump and improve energy efficiency in the time of can reducing simple arm down maneuver, can implement at an easy rate can the lifting car body hydraulic working machine.

(the 2nd example of oil hydraulic circuit)

Secondly, the 2nd example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Fig. 4.Fig. 4 is the circuit diagram of the 2nd embodiment's oil hydraulic circuit, and from this figure as can be known, this routine oil hydraulic circuit is characterised in that the switching of carrying out lifting switching valve and center by-pass flow valve with solenoid valve.

In Fig. 4, symbol 51 is to detect the pressure transducer that arm is pressed with the cylinder bottom of oil hydraulic cylinder 11, symbol 52 is the solenoid valves that are used to switch lifting switching valve 25 and center by-pass flow valve 27, symbol 53 is the controllers that read the instruction current value of the output signal of pressure transducer 51 and the signal input part that solenoid valve 52 is supplied with in output, symbol 54 is that before rodding 40 is told, the oil duct that is communicated with solenoid valve 52, symbol 55 is to connect the signal port of lifting switching valve 25 and the first rodding of solenoid valve 52, symbol 56 is the signal port of connection center by-pass flow switching valve 27 and the first rodding of solenoid valve 52, in addition, to part with it the identical symbolic representation corresponding with Fig. 2.

In controller 53, store with pressure transducer 51 detected arms the cylinder bottom pressure value of oil hydraulic cylinder 11 and the relation of the instruction current value of the signal input part of supplying with solenoid valve 52, in scope with the cylinder bottom pressure value of pressure transducer 51 detected cylinder bottom pressure values when the arm deadweight falls, promptly regulation is pressed the above occasion of P0, solenoid valve 52 maintaining valve position 52a, be in the scope of cylinder bottom pressure value of occasion that extruding force acts on arm 5 with pressure transducer 51 detected cylinder bottom pressure values, promptly press the lower pressure applications of P0 than regulation, output switches to solenoid valve 52 instruction current of switching position 52b.

Occasion at solenoid valve 52 maintaining valve position 52a, because becoming the first pilot of arm dropping signal is disconnected by solenoid valve 52, because formerly rodding 55,56 is not set up first pilot, so lifting switching valve 25 maintaining valve position 25a, the switching valve 262 of flow control valve 26 is switched to switching position 26a, and, center by-pass flow switching valve 27 maintaining valve position 27a.To this, be switched to switching position 52b at solenoid valve 52, in the occasion of carrying out the arm operation, be supplied to first rodding 55,56 owing to become the first pilot of arm dropping signal through solenoid valve 52, so lifting switching valve 25 is switched to switching position 25b, the switching valve 262 of flow control valve 26 is switched to switching position 26b, and center by-pass flow switching valve 27 is switched to switching position 27b.

Be switched to switching position 26a at switching valve 262, and the occasion of center by-pass flow switching valve 27 maintaining valve position 27a, as illustrating in the 1st embodiment, the pressure oil of supplying with piston rod chamber 11b only is the recovered oil of discharging from cylinder bottom chamber 11a, and arm 5 falls because of deadweight.On the other hand, switch to switching position 25b at lifting switching valve 25, and center by-pass flow switching valve 27 switches to the occasion of switching position 27b, as the 1st embodiment illustrated, recovered oil and from pressure oil interflow that main pump 21 is supplied with and supply with piston rod chamber 11b can access the strong extruding forces such as lifting power of car body.

The hydraulic working machine of present embodiment play with the same effect of the 1st embodiment's hydraulic working machine beyond connect the oil duct of arm owing to can omit at least, thereby can simplify oil hydraulic circuit with the signal port of the cylinder bottom chamber 11a of oil hydraulic cylinder 11 and lifting switching valve 25.

(the 3rd example of oil hydraulic circuit)

Secondly, the 3rd example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Fig. 5.Fig. 5 is the circuit diagram of the 3rd embodiment's oil hydraulic circuit, from this figure as can be known, this routine oil hydraulic circuit possesses 2 solenoid valves as the lifting switching valve, and, press with the cylinder bottom of oil hydraulic cylinder and the first pilot of position control valve is controlled the switching of these 2 solenoid valves according to arm.

In Fig. 5, symbol 51 be detect arm with the cylinder bottom of oil hydraulic cylinder 11 press the 1st pressure transducer, symbol 61, the 62nd, the 1st and the 2nd solenoid valve of formation lifting switching valve, symbol 63 is that the first pilot that detects first rodding 40 gets the 2nd pressure transducer, symbol 64 is that the output signal and the output of reading the output signal of the 1st pressure transducer 51 and the 2nd sensor 63 are used to switch the 1st and the 2nd solenoid valve 61, the controller of the instruction current value of 62 switching position, symbol 65 is the first roddings of signal port that connect the switching valve 262 of the 1st solenoid valve 61 and flow control valve 26, symbol 66 is the first roddings that connect the signal port of the 2nd solenoid valve 62 and center by-pass flow switching valve 27, in addition, for the symbolic representation identical of the part of Fig. 2 correspondence with it.

As shown in Figure 5, controller 64 is by constituting with lower member: the 1st reservoir 71, and it stores with the 1st pressure transducer 51 detected arms the cylinder bottom pressure value (BM/B pressure) of oil hydraulic cylinder 11 and the relation of the instruction current value of the signal input part of supplying with the 1st and the 2nd solenoid valve 61,62; The 2nd reservoir 72, it stores with the first pilot (arm dropping signal) of the 2nd pressure transducer 63 detected first roddings 40 and the relation of the instruction current value of the signal input part of supplying with the 1st solenoid valve 62; Minimum value is selected loop 73, and it is selecting little instruction current value to supply with the signal input part of above-mentioned the 1st solenoid valve 62 from the instruction current value of above-mentioned the 1st reservoir 71 outputs with between the instruction current value of above-mentioned the 2nd reservoir 72 outputs.

And, adopt the words of this routine controller 64, in with the scope of pressure transducer 51 detected arms with the cylinder bottom pressure value of cylinder bottom pressure value when arm falls because of deadweight of oil hydraulic cylinder 11, promptly regulation is pressed the above occasion of P0, because from the instruction current value of the 1st reservoir 71 outputs is little value, thus the 1st solenoid valve 61 maintaining valve position 61a, in addition, select the little instruction current of loop 73 output values from minimum value, and irrelevant with the size of the instruction current of exporting from the 2nd reservoir 72.For this reason, also maintaining valve position 62a of the 2nd solenoid valve 62.Therefore, owing to the signal port of the pressure oil that sprays from pioneer pump 24 through the switching valve 262 of the 1st solenoid valve 61 and first rodding 65 supply flow control valves 26, so, switching valve 262 is switched to switching position 26a, and, oily from the pressure of pioneer pump 24 ejections owing to disconnected by the 2nd solenoid valve 62, formerly do not set up first pilot in the rodding 66, center by-pass flow switching valve 27 maintaining valve position 27a.

On the other hand, with pressure transducer 51 detected arms with the cylinder bottom pressure value of oil hydraulic cylinder 11 in extruding force affacts the scope of cylinder bottom pressure value of occasion of arm 5, promptly press the lower pressure applications of P0 than regulation, because from the instruction current value of the 1st reservoir 71 outputs is big value, thereby the 1st solenoid valve 61 switches to switching position 61b.In addition, select loop 73 outputs and the corresponding electric current of exporting from the 2nd reservoir 72 of instruction current from minimum value.Therefore, when carrying out the arm down maneuver, the 2nd solenoid valve 62 switches to switching position 62b, and center by-pass flow switching valve 27 switches road switching position 27b.Conversely, in the occasion of not carrying out the arm step-down operation, because the 2nd solenoid valve 62 maintaining valve position 62a, so center by-pass flow switching valve 27 maintaining valve position 27a.

Switching valve 262 at flow control valve 26 is switched to switching position 26a, and the occasion of center by-pass flow switching valve 27 maintaining valve position 27a, as illustrating in the 1st embodiment, only the recovered oil of discharging from cylinder bottom chamber 11a is supplied with piston rod chamber 11b, arm 5 falls because of deadweight.On the other hand, be switched to switching position 61b, 62b respectively at the 1st solenoid valve 61 that constitutes lifting switching valve 25 and the valve position of the 2nd solenoid valve 62, and center by-pass flow switching valve 27 switches to the occasion of switching position 27b, as having illustrated among the 1st embodiment, owing to recovered oil with from pressure oil interflow and supply piston rod chamber 11b that main pump 21 is supplied with, thus the strong extruding forces such as lifting power of generation car body.

In addition,, also know characteristic difference separately to the above-mentioned the 1st and the 2nd reservoir 71,72 from Fig. 5.This be because, all have lifting switching valve 25 and center by-pass flow switching valve 27 to link respectively and the relation switched with respect to the above-mentioned the 1st and the 2nd embodiment, in the 3rd embodiment, lifting switching valve 25 and center by-pass flow switching valve 27 have the independent separately relation of switching.As previously mentioned, when arm cylinder bottom pressure ratio P0 is lower in the 1st reservoir 71, no matter whether the arm step-down operation is carried out the 1st solenoid valve 61 that constitutes lifting switching valve 25 is switched to switching position 61b.

On the other hand, P0 is lower in arm cylinder bottom pressure ratio, and when not carrying out the arm step-down operation, because from the instruction current value pi of the 1st reservoir 71 outputs is big value, from the instruction current value pi of the 2nd reservoir 72 outputs is little value, thereby instruction current value pi little among both selects loop 73 to be output from minimum value, and center by-pass flow switching valve 27 can not be switched at switching position 27a.Therefore, suppose earlier center by-pass flow switching valve 27 to be switched to switching position 27b before the 1st solenoid valve 61 is switched to switching position 61B, the pump ejection is pressed invalidly and is risen, and the result makes energy utilization efficiency variation.

The hydraulic working machine of present embodiment also can play the effect same with the 2nd embodiment's hydraulic working machine.

(the 4th example of oil hydraulic circuit)

Secondly, the 4th example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Fig. 6.Fig. 6 is the circuit diagram of the 4th embodiment's oil hydraulic circuit, from this figure as can be known, this routine oil hydraulic circuit is characterised in that the first pilot that produces according to the reduction valve 23b that constitutes operation equipment 23, promptly according to the switching of arm dropping signal travel direction control valve 22, flow control valve 26 and center by-pass flow switching valve 27.

In Fig. 6, symbol 51 is to detect the 1st pressure transducer that arm is pressed with the cylinder bottom of oil hydraulic cylinder 11, symbol 81, the 82nd, the 1st and the 2nd solenoid valve of formation lifting switching valve, symbol 83 is that the output signal and the output of reading pressure transducer 51 are used to switch the 1st and the 2nd solenoid valve 81, the controller of the instruction current value of 82 switching position, symbol 84 is that before rodding 40 separates, the first rodding that is connected with the 1st solenoid valve 81, symbol 85 is that before rodding 40 separates, the first rodding that is connected with the 2nd solenoid valve 82, symbol 86 is the first roddings of signal port that connect the switching valve 262 of the 1st solenoid valve 81 and flow control valve 26, symbol 87 is the first roddings that connect the signal port of the 2nd solenoid valve 82 and center by-pass flow switching valve 27, symbol 88 is to connect on the arm that the 2nd solenoid valve 82 and operation equipment 23 possessed lift operations with the first rodding of reduction valve 23c, symbol 89 is provided in a side of the one-way valve of the tie point of first rodding 87 and first rodding 88, in addition, part with it the identical symbolic representation corresponding with Fig. 2.

As shown in Figure 6, controller 83 is by constituting with lower member: the 1st reservoir 91, and it stores with the 1st pressure transducer 51 detected arms the cylinder bottom pressure value of oil hydraulic cylinder 11 and the relation of the instruction current value of the signal input part of supplying with the 1st solenoid valve 81; The 2nd reservoir 92, it stores with the cylinder bottom pressure value of the 1st pressure transducer 51 detected oil hydraulic cylinders 11 and the relation of the instruction current value of the signal input part of supplying with the 2nd solenoid valve 82.In addition, the default current value of above-mentioned instruction current value as benchmark, the current value of this setting as the instruction current value.

And, words according to this routine controller 83, in with the scope of pressure transducer 51 detected arms with the cylinder bottom pressure value of cylinder bottom pressure value when the arm deadweight falls of oil hydraulic cylinder 11, promptly in the occasion of stipulating to press more than the P0, the 1st solenoid valve 81 utilizes from the instruction current value maintaining valve position 81a of the 1st reservoir 91 outputs, and the 2nd solenoid valve 82 utilizes from the instruction current value maintaining valve position 82a of the 2nd reservoir 92 outputs.Therefore, in the occasion of carrying out the arm step-down operation, before rodding 40 is supplied to the signal port of the switching valve 262 of flow control valve 26 through first rodding the 84, the 1st solenoid valve 81 and first rodding 86, because switching valve 262 is switched to switching position 26a, and, elder generation's rodding 85 is disconnected by the 2nd solenoid valve 82, so formerly rodding 87 is not set up first pilot, and center by-pass flow switching valve 27 maintaining valve position 27a.

On the other hand, with pressure transducer 51 detected arms with the cylinder bottom pressure value of oil hydraulic cylinder 11 in extruding force acts on the scope of cylinder bottom pressure value of occasion of arm 5, promptly press the lower occasion of P0 than regulation, the 1st solenoid valve 81 utilizes from the instruction current value of the 1st reservoir 91 outputs and switches to switching position 81b, and the 2nd solenoid valve 82 utilizes from the instruction current value of the 2nd reservoir 92 outputs and switches to switching position 82b.Therefore, because first rodding 84 is disconnected by the 1st switching valve 81, so formerly rodding 86 is not set up first pilot, flow control valve 26 is switched to switching position 26b, and, become the state that first rodding 40 and first rodding 87 are communicated with.Therefore, carry out the words of arm step-down operation, because descending, arm is supplied to the signal port of center by-pass flow switching valve 27 with the first rodding 40 of first pilot process, first rodding the 85, the 2nd solenoid valve 82 and first rodding 87, so center by-pass flow switching valve 27 is switched to switching position 27b.

Switching valve 262 at flow control valve 26 is switched to switching position 26a, and center by-pass flow switching valve 27 is switched to the occasion of switching position 27a, as the 1st embodiment illustrated, only the recovered oil of discharging from cylinder bottom chamber 11a is supplied with piston rod chamber 11b, arm 5 falls because of deadweight.On the other hand, be switched to switching position 81b, 82b at the 1st solenoid valve 81 and the 2nd solenoid valve 82 that constitute lifting switching valve 25, and center by-pass flow switching valve 27 switches to the occasion of switching position 27b, as having illustrated among the 1st embodiment, owing to recovered oil with from pressure oil interflow and supply piston rod chamber 11b that main pump 21 is supplied with, thus the strong extruding forces such as lifting power of generation car body.

In addition, same with above-mentioned the 3rd embodiment, in the present embodiment, concerning the above-mentioned the 1st and the 2nd reservoir 91,92, characteristic difference separately.This is because same with the 3rd embodiment, lifting switching valve 25 and center by-pass flow switching valve 27 have the independent respectively relation of switching.Particularly in the present embodiment, have different separately characteristics, can change lifting switching valve 25 and center by-pass flow switching valve 27 switching timing is separately set by making 2 reservoir.For example, words with reference to the characteristic relation of Fig. 6, press (BM/B pressures) to liken the lower occasion of setting pressure P0 at the arm cylinder bottom into benchmark, because pressing Pi in instruction when set pressing the littler value of P0 be relation from the 1st reservoir 91 ratios from the more Zao output of the 2nd reservoir 92, so switching valve 262 is than center by-pass flow switching valve 27 more Zao being switched.Like this, by lifting switching valve 25 is switched more earlier than center by-pass flow switching valve 27, can work well with the same energy efficiency of the 3rd embodiment.

The hydraulic working machine electricity of present embodiment plays the effect same with the 2nd embodiment's hydraulic working machine.

(the 5th example of oil hydraulic circuit)

Secondly, the 5th example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Fig. 7.Fig. 7 is the circuit diagram of the 5th embodiment's oil hydraulic circuit, and from this figure as can be known, this routine oil hydraulic circuit is characterised in that, traveling gear is driven with oil hydraulic circuit and arm driving make up with oil hydraulic circuit.

In Fig. 7, symbol 8 is right lateral fluid pressure motors, symbol 9 is left lateral fluid pressure motors, symbol 101 is the 2nd main pumps, symbol 102 is that control is supplied with 2nd position control valve of right lateral with the flow direction of the pressure oil of fluid pressure motor 8 from main pump 21, symbol 103 is that control is supplied with 3rd position control valve of left lateral with the flow direction of the pressure oil of fluid pressure motor 9 from the 2nd main pump 101, symbol 104 is to supply with 4th position control valve of arm with the flow direction of the pressure oil of oil hydraulic cylinder 11 from the 2nd main pump 101 when being controlled at the arm down maneuver, symbol 105 is to be used for the switching valve of the Pressure oil feeder left lateral of supplying with from the 1st main pump 21 with fluid pressure motor 9 sides in the occasion of carrying out the arm step-down operation, symbol 106 is in the occasion of carrying out the arm operation, switching signal is given the shuttle valve of switching valve 105, symbol 107 is the oil ducts that are communicated with the 2nd main pump 101 and the 4th direction switching valve 104, symbol 108 is the center by-pass flow paths that are communicated with the 2nd main pump 101 and fuel tank 28, symbol 109 is oil ducts that connection the 4th direction switching valve 104 and arm are used the piston rod chamber 11b of oil hydraulic cylinder 11, symbol 110 is oil ducts that connection the 4th direction switching valve 104 and arm are used the cylinder bottom chamber 11a of oil hydraulic cylinder 11, symbol 111 is provided in a side of the one-way valve on the oil duct 110, symbol 112 is the oil ducts that connect main pump 21 and switching valve 105, symbol 113 is provided in a side of the one-way valve of oil duct 112, symbol 114 is the oil ducts that connect switching valve 105 and the 3rd position control valve 103, symbol 115 is the first rodding of the first pilot guiding lifting switching valve 25 that becomes the arm dropping signal, symbol 116 is first roddings of the arm dropping signal being supplied with the signal port of the 4th position control valve 104, symbol 117 is first roddings of the arm rising signals being supplied with the signal port of the 4th position control valve 104, symbol 118 is first roddings of switching signal being supplied with the signal port of switching valve 105, in addition, part with it the identical symbolic representation corresponding with Fig. 2.

Below, the 5th embodiment's that as above constitutes hydraulic working machine is described.

As shown in Figure 7, in the occasion of operating stem 23a in the neutral position, position control valve 22 and the 4th position control valve 104 maintain a neutral position separately 22b and neutral position 104b, lifting switching valve 25 switches to switching position 25a because of arm with the pressure of the cylinder bottom side of oil hydraulic cylinder 11.At this state, first rodding 43 is communicated with fuel tank 28, center by-pass flow switching valve 27 maintaining valve position 27a, switching valve 105 maintaining valve position 105a.Therefore, be directed to fuel tank 28 from the pressure oil of main pump 21 ejections through center by-pass flow mouth, oil duct 37, center by-pass flow switching valve 27 and the oil duct 38 of oil channel 31, position control valve 22, in addition, owing to be directed to fuel tank 28 through the center by-pass flow mouth of oil channel 107, oil duct the 108, the 3rd position control valve 103, press oil not to be supplied to cylinder bottom chamber 11a and the piston rod chamber 11b of arm with oil hydraulic cylinder 11 from the pressure oil of the 2nd main pump 101 ejections.

From this state to illustrated left to, i.e. arm descent direction operating operation bar 23a, 24 that supply with from pioneer pump, be depressurized the first pilot that valve 23b reduced pressure and exported to first rodding 40, position control valve 22 is switched to switching position 22a.On the other hand, because this elder generation's pilot is directed to first rodding 115, process lifting switching valve 25 is directed to the signal port of switching valve 262, so switching valve 262 is switched to switching position 26a.Like this, through throttling 29b, one-way valve 29c and oil duct 35 and in piston rod chamber 11b regeneration, and the remaining oil that returns returns fuel tank 28 through throttling 29a and oil duct 39 from the part of returning oil of cylinder bottom chamber 11a.

In this occasion, when the working pressure of cylinder bottom pressure ratio lifting switching valve 25 is higher, because lifting switching valve 25 maintains valve position 25a, so, the switching position of flow control valve 26 also maintains switching position 26a, and in addition, center by-pass flow switching valve 27 also maintains valve position 27a.Therefore, from the pressure oil of main pump 21 ejection through oil channel 31, the center by-pass flow mouth of position control valve 22, oil duct 37, center by-pass flow switching valve 27 and oil duct 38 and be directed to fuel tank 28, in addition, oily from the pressure of the 2nd main pump 101 ejections because through oil channel 107, oil duct 108, the center by-pass flow mouth of the 3rd position control valve 103 and be directed to fuel tank 28, so, press oil not to be supplied to cylinder bottom chamber 11a and the piston rod chamber 11b of arm with oil hydraulic cylinder 11, only will supply with piston rod chamber 11b from the recovered oil that cylinder bottom chamber 11a discharges, deadweight because of arm 5, arm dwindles with oil hydraulic cylinder 11, and arm 5 falls because of deadweight.

On the other hand, in the occasion of operating stem 23a to the operation of arm descent direction, when the working pressure of cylinder bottom pressure ratio lifting switching valve 25 is lower, because lifting switching valve 25 is switched to switching position 25b, so first rodding 45 is communicated with fuel tank 28 through lifting switching valve 25, the switching valve 262 of flow control valve 26 is switched to valve position 26b.Therefore, be supplied to the inlet restriction mouth of position control valve 22 through oil channel 32, flow control valve 26, oil duct 33 from the pressure oil of main pump 21 ejections.In addition, be accompanied by the switching of lifting switching valve 25, owing to be supplied to the signal port of center by-pass flow switching valve 27 through first rodding 115, lifting switching valve 25, first rodding 43 as the first pilot of arm dropping signal, so, center by-pass flow switching valve 27 is switched to switching position 27b, and, because the first rodding 116 of process is supplied to the signal port of the arm decline side of the 4th position control valve 104, so the 4th position control valve 104 is switched to switching position 104a.Therefore, be supplied to the piston rod chamber 11b of arm from the pressure oil of main pump 21 ejections with oil hydraulic cylinder 11, and, be supplied to the piston rod chamber 11b of arm from the pressure oil of the 2nd main pump 101 ejections through the 4th position control valve 104, oil duct 109 and oil duct 35 with oil hydraulic cylinder 11, be supplied to piston rod chamber 11b owing to the recovered oil of discharging with from the pressure oil of main pump 21 supplies and from the pressure oil interflow that the 2nd main pump 101 is supplied with, thereby can produce the strong extruding forces such as lifting power of car body from cylinder bottom chamber 11a.

In addition, because the arm operation is directed to switching valve 105 with first pilot through shuttle valve 106, oil duct 118, so, switching valve 105 is switched to switching position 105b, and the pressure oil that sprays from main pump 21 is supplied to walking fluid pressure motor 8,9 about each through the 2nd position control valve 102 and the 3rd position control valve 103.Like this, operate arm and when walking at the same time, because the walking motor 8,9 about being supplied to from the pressure oil of main pump 21, be supplied to arm with oil hydraulic cylinder 11 from the pressure oil of the 2nd main pump 101, so the lifting of the car body of the composite move of feasible walking operation and arm down maneuver becomes possibility.

In addition, in above-mentioned the 5th embodiment, used hydraulic pilot formula switching valve as lifting switching valve 25, but same with above-mentioned the 2nd to the 4th embodiment's hydraulic working machine, also can use electromagnetism hydraulic type or electromagnetic type switching valve.

(the 6th example of oil hydraulic circuit)

Secondly, the 6th example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Fig. 8 and Fig. 9.Fig. 8 is the major component circuit diagram of the oil hydraulic circuit of the 6th mode of execution, Fig. 9 is the pie graph of the shuttle valve group that oil hydraulic circuit possessed of the 6th mode of execution, from these figure as can be known, this routine oil hydraulic circuit is characterised in that, possess hydraulic pilot formula switching valve as the lifting switching valve, and the Pressure oil feeder oil hydraulic cylinder from a variable capacity hydraulic pump.

This routine oil hydraulic circuit is with respect to the 1st embodiment shown in Figure 2, as shown in Figure 2, mainly by constituting: variable capacity hydraulic pump (main pump) 21 with lower member, modulating valve (control mechanism verts) 21a of the discharge capacity of control variable capacity hydraulic pump 21, stretch because of the pressure that sprays from variable capacity hydraulic pump 21 is oily, drive the dbl act arm oil hydraulic cylinder 11 of arm (job factor) 5, control is supplied with the position control valve 22 of arms with the flow direction of the pressure oil of the cylinder bottom chamber 11a of oil hydraulic cylinders (actuator) 11 and piston rod chamber 11b from variable capacity hydraulic pump 21, the pilot operated device 23 of the handover operation of travel direction control valve 22, pioneer pump 24, control is from the lifting switching valve 25 of the flow direction of the pressure oil of pioneer pump 24 ejections, be connected with the inlet restriction mouth of position control valve 22 at the upstream side of position control valve 22, utilize lifting switching valve 25 to carry out the flow control valve 26 of handover operation, be connected with the center by-pass flow mouth of position control valve 22 in the downstream side of position control valve 22, utilize lifting switching valve 25 to carry out the center by-pass flow switching valve 27 of handover operation, fuel tank 28 outputs to tilt control signal according to the signal from pilot operated device 23 and not shown other pilot operated devices that go out the shuttle valve group (indicating device of verting) 30 of modulating valve 21a.

Above-mentioned position control valve 22 possesses the regenerative circuit of being made up of throttling 29a, 29b and one-way valve 29c.

As shown in Figure 3, above-mentioned pilot operated device 23 is made of operating stem 23a, the arm decline side reduction valve 23b, the arm uplifted side reduction valve 23c that utilize this operating stem 23a to carry out handover operation.

Pilot port at above-mentioned lifting switching valve 25 possesses the swing of preventing throttling 25d.

Above-mentioned flow control valve 26 is by poppet valve 261, and the leading type switching valve 262 that is communicated with, disconnects the pumping hole side of the back pressure chamber of this poppet valve 261 and position control valve 22 is formed.

As shown in Figure 9, above-mentioned shuttle valve group 30 is combined by shuttle valve 301～315 and hydraulic pressure switching valve 317,318.In addition, this shuttle valve group 30 also can connect the valve group of each shuttle valve and hydraulic pressure switching valve in order to pipe arrangement, also can be used in pack into the valve group of desired shuttle valve and hydraulic pressure switching valve of one in the piece main body.

Among the shuttle valve 301～315, shuttle valve 301～307 is configured in the epimere of shuttle valve group 30, shuttle valve 301 is selected the high pressure side of the right back operation signal pressure Ar that advances of the right front operation signal pressure Af that advances of walking and walking, shuttle valve 302 is selected the high pressure side of the left back operation signal pressure Br that advances of the left front operation signal pressure Bf that advances of walking and walking, the high pressure side of the operation signal pressure Cc of shuttle valve 303 selection scraper bowl grouting (バ ケ Star ト Network ラ ウ De) and the operation signal pressure Cd of scraper bowl dumping, the high pressure side of the operation signal Du that shuttle valve 304 selection arms rise and the operation signal pressure G of lifting, the high pressure side of the operation signal pressure Ec of shuttle valve 305 selection cantilever grouting and the operation signal pressure Ed of cantilever dumping, the high pressure side of the operation signal pressure Fr of shuttle valve 306 selection right rotations and the operation signal pressure F1 of anticlockwise, the high pressure side that shuttle valve 307 is selected from the operation signal pressure of 1 pair of pilot valve, this pilot valve are the pilot valves that preparation actuator is connected to the pilot operated device of preparation that is provided with when preparing position control valve.

Shuttle valve 308～310 is configured in the 2nd section of shuttle valve group 30, shuttle valve 308 is selected with the shuttle valve 301 of epimere and the high pressure side of the selected separately operation signal pressure of shuttle valve 302, shuttle valve 309 is selected with the shuttle valve 304 of epimere and the high pressure side of the selected separately operation signal pressure of shuttle valve 305, and shuttle valve 310 is selected the high pressure side with the selected separately operation signal pressure of the shuttle valve 306 of epimere and shuttle valve 307.

Shuttle valve 311,312 is configured in the 3rd section of shuttle valve group 30, shuttle valve 311 is selected with the shuttle valve 303 of epimere and the high pressure side of the 2nd section selected separately operation signal pressure of shuttle valve 309, and shuttle valve 312 is selected the high pressure side with the 2nd section shuttle valve 309 and the selected separately operation signal pressure of shuttle valve 310.

Shuttle valve 313,314 is configured in the 4th section of shuttle valve group 30, shuttle valve 313 is selected with the shuttle valve 301 of epimere and the high pressure side of the 3rd section selected separately operation signal pressure of shuttle valve 311, and shuttle valve 304 is selected the high pressure side with the 3rd section shuttle valve 311 and the selected separately operation signal pressure of shuttle valve 312.

Shuttle valve 315 is configured in the 5th section of shuttle valve group 30, selects with the 4th section shuttle valve 314 selected operation signal pressure and the high pressure side of arm step-down operation signal pressure Dd.

Hydraulic pressure switching valve 317 is to be directed to compression zone 317a, to produce the proportional pressure-reducing valve of control signal pressure (pump control signal Xp1) based on its maximum pressure work, by the pressure of pioneer pump 24 with the maximum pressure that shuttle valve 313 is selected.This hydraulic pressure switching valve 317, at the maximum pressure of selecting with shuttle valve 313 when tank pressure is following, in illustrated position and make control signal pressure be reduced to fuel tank to press, the maximum pressure of selecting with shuttle valve 313 is when tank pressure is above, be switched from illustrated position, the pressure of pioneer pump 24 reduced pressure and the horizontal control signal corresponding pressure of this maximum pressure and output.The modulating valve 21a of variable capacity hydraulic pump 21 utilizes this control signal pressure (pump control signal Xp1) work.

Modulating valve 21a has the characteristic of verting and increasing that makes variable capacity hydraulic pump 21 along with the pressure rising of pump control signal Xp1, gives pump control signal Xp1, the then corresponding therewith ejection flow increase and decrease that makes variable capacity hydraulic pump 21.Like this, when guide's operation equipment 23 is operated, position control valve 22 is switched, and, from the pressure oil of variable capacity hydraulic pump 21 ejections with the corresponding flow of operation signal pressure (operation amount of pilot operated device 23), this pressure oil is supplied to cylinder bottom chamber 11a or the piston rod chamber 11b of arm with oil hydraulic cylinder 11, and arm is stretched with oil hydraulic cylinder 11.

Hydraulic pressure switching valve 318 is that the maximum pressure of selecting with shuttle valve 315 is directed to compression zone 318a, based on its maximum pressure work, is produced the proportional pressure-reducing valve of control signal pressure (preceding operation Xf) by the pressure of pioneer pump 24.This hydraulic pressure switching valve 318, at the maximum pressure of selecting with shuttle valve 315 when tank pressure is following, make control signal pressure be reduced to fuel tank presses in illustrated position, the maximum pressure of selecting with shuttle valve 315 is when tank pressure is above, be switched from illustrated position, the pressure of pioneer pump 24 reduced pressure and the horizontal control signal corresponding pressure of this maximum pressure and output.Scheme unshowned rotating regulation valve and utilize this this control signal pressure (preceding operation Xf) work with the walking connecting valve.

The 6th embodiment is with respect to the 1st embodiment, that modulating valve (control mechanism verts) 21a is set is different with the structure of the shuttle valve group that tilt control signal is outputed to this modulating valve 21a (indicating device of verting) 30 owing to only have basically, so only the action of the 1st embodiment and structure connection is described.

Operating stem 23a is in the neutral position, from tensile force do not act on arm with the state of oil hydraulic cylinder 11 to the diagram left to, i.e. arm descent direction operating operation bar 23a, arm 5 is to descent direction rotation (so-called deadweight falls).

When arm 5 deadweights fell, the pressure oil that produces with pilot operated device 23 did not enter the lifting signal input G of shuttle valve group 30, enters arm dropping signal inlet opening Dd.The pressure of lifting signal input G is being selected other a plurality of operation signals and maximal pressure and is being switched to hydraulic pressure switching valve 317 but do not have operated occasion at not shown other pilot operated devices that go out, and hydraulic pressure switching valve 317 is not switched, and keeps the state of Fig. 9.Like this, fuel tank is pressed and is output from shuttle valve group 30 as pump control signal Xp1, through modulating valve 21a control variable capacity hydraulic pump 21 minimizing capacity.

On the other hand, at operating stem 23a to the operated occasion of arm descent direction, when the switch pressure of cylinder bottom pressure ratio lifting switching valve 25 is lower, same with the 1st embodiment, come to be supplied to the piston rod chamber 11b of arm with the recovered oil of discharging by oil duct 35, can produce the strong extruding forces such as lifting power of car body with oil hydraulic cylinder 11 from cylinder bottom chamber 11a since the pressure oil of the variable capacity hydraulic pump 21 of the inlet restriction mouth of oil duct 33 feeding direction control valves 22.

When lifting, the pressure oil that produces on guide's operation equipment 23 enters the lifting signal input G of shuttle valve group 30, selects other a plurality of signals and maximal pressure and switches hydraulic pressure switching valve 317.Like this, export from the shuttle valve group as pump control signal Xp1 with the corresponding pressure of above-mentioned maximal pressure, through modulating valve 21a, control variable capacity hydraulic pump 21 increase capacity.

In addition, to illustrated right, i.e. the occasion of arm ascent direction operation is utilized the pressure oil of supplying with from pioneer pump 24 at operating stem 23a, and arm rises and exported to first rodding 41 with first pilot, and position control valve 22 switches to switching position 22c.Like this, because the pressure oil of discharging from piston rod chamber 11b returns fuel tank 28 through oil channel 35, position control valve 22, oil duct 39, so, cylinder bottom presses to compared with the lower pressure of the working pressure of heavy switching valve 25, lifting switching valve 25 is switched to switching position 25b, and flow control valve 26 switches to switching position 26b.Therefore, pressure oil from the variable capacity hydraulic pump 21 of the inlet restriction mouth that is supplied to position control valve 22 through oil channel 32, flow control valve 26, oil duct 33, be supplied to cylinder bottom chamber 11a through oil channel 34, arm 5 usefulness oil hydraulic cylinders 11 are stretched, and arm rotates to ascent direction.

When arm rose, the pressure oil that produces on guide's operation equipment 23 entered the arm rising signals inlet opening Du of shuttle valve group 30, selects other a plurality of signals and maximal pressure and switches hydraulic pressure switching valve 317.Like this, export from shuttle valve group 30 as pump control signal Xp1 with the corresponding pressure of above-mentioned maximal pressure, by modulating valve 21a, control variable capacity hydraulic pump 21 increase capacity.

The hydraulic working machine of present embodiment monitors the variation that arm is pressed with the cylinder bottom of oil hydraulic cylinder 11, arm is pressed in regulation with the cylinder bottom of oil hydraulic cylinder 11 and presses when above when the arm down maneuver, lifting switching valve 25 is switched to switching position 25a, like this, the switching valve 262 of flow control valve 26 is switched to switching position 26a, and make center by-pass flow valve 27 be valve position 27a, because not from the Pressure oil feeder arm of variable capacity hydraulic pump 21 ejection piston rod chamber 11b, so the consumption power of pump can be reduced in the simple arm down maneuver of the extruding force that do not need to be used for the lifting car body time with oil hydraulic cylinder 11.In addition, owing to when simple arm down maneuver, the Pressure oil feeder arm that sprays from variable capacity hydraulic pump 21 is not used the piston rod chamber 11b of oil hydraulic cylinder 11, thereby when making arm 5 and other job factors such as cantilever 6 or scraper bowl 7 composite moves, can make and supply with cantilever from variable capacity hydraulic pump and increase over the ground, can improve the energy efficiency of hydraulic working machine with oil hydraulic cylinder 12 or scraper bowl pressure oil phase with oil hydraulic cylinder 13.On the other hand, arm is pressed in regulation with the cylinder bottom of oil hydraulic cylinder 11 and presses when following when the arm down maneuver, lifting switching valve 25 is switched to valve position 25b, like this, the switching valve 262 of flow control valve 26 is switched to switching position 26b, and center by-pass flow switching valve 27 is switched to switching position 27b, because the piston rod chamber 11b that uses oil hydraulic cylinder 11 from the Pressure oil feeder arm of variable capacity hydraulic pump 21 ejections, thereby can produce very big extruding force to arm 5, make the lifting of car body become possibility.

In addition, because arm is pressed in regulation with the cylinder bottom of oil hydraulic cylinder 11 and presses when above when arm 5 down maneuvers, control reduces the discharge capacity of variable capacity type oil hydraulic pump 21, arm is pressed in regulation with the cylinder bottom of oil hydraulic cylinder 11 and presses when following when arm 5 down maneuvers, utilize modulating valve 21a control to increase the discharge capacity of variable capacity type oil hydraulic pump 31, thereby the consumption power of pump in the time of can reducing simple arm down maneuver, can reduce the fuel cost of hydraulic working machine, and, thereby owing to can be promptly when the squeeze job of arm 5 can steadily successfully carry out change to the Pressure oil feeder arm of necessary amount with oil hydraulic cylinder 11 from the simple down maneuver of arm 5 to squeeze job.

In addition, there are not the each several part of special instruction and the action and above-mentioned the 1st mode of execution of each several part to constitute comparably, move comparably.

In addition, in the various embodiments described above, is that example is illustrated to be used to drive arm with the oil hydraulic circuit of oil hydraulic cylinder 11, but main idea of the present invention is not limited thereto, and also can adopt and above-mentioned same structure the oil hydraulic circuit of the oil hydraulic cylinder that is used to drive other job factors.

For example, the oil hydraulic cylinder of using as other job factors can exemplify out cantilever oil hydraulic cylinder 12.Utilize this cantilever to be with the action that oil hydraulic cylinder 12 carries out lifting, at first, cantilever 6 is positioned at than the part that connects cantilever 6 and arm 5 front side more, with oil hydraulic cylinder 12, cantilever 6 is rotated to the driver's seat direction erect up to cantilever from the state stretching cantilever that scraper bowl 7 is squeezed in ground.In order to carry out this action, pressing oil to import the not shown cylinder bottom chamber side that go out of cantilever with oil hydraulic cylinder 12, stretching cantilever usefulness oil hydraulic cylinder 12.At this moment, monitor the pressure of cantilever, when the pressure in this piston rod chamber is low,,, just can when lifting, produce strong power by adopting this structure pressing oil to import the cylinder bottom chamber of cantilever cylinder with the piston rod chamber of oil hydraulic cylinder 12.

(the 7th example of oil hydraulic circuit)

Secondly, the 7th example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Figure 10.Figure 10 is the circuit diagram of the 7th embodiment's oil hydraulic circuit, and from this figure as can be known, this routine oil hydraulic circuit is characterised in that the switching of carrying out lifting switching valve and center by-pass flow switching valve with solenoid valve.

In Figure 10, symbol 51 is to detect the pressure transducer that arm is pressed with the cylinder bottom of oil hydraulic cylinder 11, symbol 52 is the solenoid valves that are used to switch lifting switching valve 25 and center by-pass flow switching valve 27, symbol 53 is the controllers that read the instruction current value of the output signal of pressure transducer 51 and the signal input part that solenoid valve 52 is supplied with in output, symbol 54 is that before rodding 40 is told, the oil duct that is communicated with solenoid valve 52, symbol 55 is to connect the signal port of lifting switching valve 25 and the first rodding of solenoid valve 52, symbol 56 is the signal port of connection center by-pass flow switching valve 27 and the first rodding of solenoid valve 52, in addition, to part with it the identical symbolic representation corresponding with Fig. 8.

In controller 53, store with pressure transducer 51 detected arms the cylinder bottom pressure value of oil hydraulic cylinder 11 and the relation of the instruction current value of the signal input part of supplying with solenoid valve 52, in scope with the cylinder bottom pressure value of pressure transducer 51 detected cylinder bottom pressure values when the arm deadweight falls, promptly in the occasion of stipulating to press more than the P0, solenoid valve 52 maintaining valve position 52a, with pressure transducer 51 detected cylinder bottom pressure values in extruding force acts on the scope of cylinder bottom pressure value of occasion of arm 5, promptly press the lower pressure applications of P0 than regulation, output switches to solenoid valve 52 instruction current of switching position 52b.

Occasion at solenoid valve 52 maintaining valve position 52a, because becoming the first pilot of arm dropping signal is disconnected by solenoid valve 52, formerly rodding 55,56 is not set up first pilot, so, lifting switching valve 25 maintaining valve position 25a, the switching valve 262 of flow control valve 26 switches to switching position 26a, and, center by-pass flow switching valve 27 maintaining valve position 27a.To this, solenoid valve 52 is switched to switching position 52b, in the occasion of carrying out the arm operation, be supplied to first rodding 55,56 by the first pilot of doing as the arm dropping signal through solenoid valve 52, so lifting switching valve 25 is switched to switching position 25b, the switching valve 262 of flow control valve 26 is switched to switching position 26b, and center by-pass flow switching valve 27 is switched to switching position 27b.

Be switched to switching position 26a at switching valve 262, and the occasion of center by-pass flow switching valve 27 maintaining valve position 27a, as illustrating in the 1st embodiment, the pressure oil of supplying with piston rod chamber 11b only is the recovered oil of discharging from cylinder bottom chamber 11a, and arm 5 falls because of deadweight.And, in this occasion, utilize shuttle valve group 30, press suitable pump control signal Xp1 to be output to modulating valve 21a with fuel tank, control reduces the discharge capacity of variable capacity hydraulic pump 21.On the other hand, switch to switching position 25b at lifting switching valve 25, and center by-pass flow switching valve 27 switches to the occasion of switching position 27b, as the 1st embodiment illustrated, recovered oil and from pressure oil interflow that variable capacity hydraulic pump 21 is supplied with and supply with piston rod chamber 11b can access the strong extruding forces such as lifting power of car body.And, in this occasion, utilize shuttle valve group 30 to output to modulating valve 21a with the corresponding pump control signal Xp1 of maximal pressure that selects with shuttle valve group 30, control increases the discharge capacity of variable capacity hydraulic pump 21.

The hydraulic working machine of present embodiment play with the same effect of the 6th embodiment's hydraulic working machine beyond connect the oil duct of arm owing to can omit at least, thereby can simplify oil hydraulic circuit with the signal port of the cylinder bottom chamber 11a of oil hydraulic cylinder 11 and lifting switching valve 25.

(the 8th example of oil hydraulic circuit)

Secondly, the 8th example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Figure 11.Figure 11 is the circuit diagram of the 8th embodiment's oil hydraulic circuit, from this figure as can be known, this routine oil hydraulic circuit is characterised in that to possess two solenoid valves as the lifting switching valve, and, press with the cylinder bottom of oil hydraulic cylinder and the first pilot of position control valve is controlled the switching of these two solenoid valves according to arm.

In Figure 11, symbol 51 is to detect the 1st pressure transducer that arm is pressed with the cylinder bottom of oil hydraulic cylinder 11, symbol 61, the 62nd, the 1st and the 2nd solenoid valve of formation lifting switching valve, symbol 63 is the 2nd pressure transducers that detect the first pilot of first rodding 40, symbol 64 is that the output signal and the output of reading the output signal of the 1st pressure transducer 51 and the 2nd sensor 63 are used to switch the 1st and the 2nd solenoid valve 61, the controller of the instruction current value of 62 switching position, symbol 65 is the first roddings of signal port that connect the switching valve 262 of the 1st solenoid valve 61 and flow control valve 26, symbol 66 is the first roddings that connect the signal port of the 2nd solenoid valve 62 and center by-pass flow switching valve 27, in addition, for part with it the identical symbolic representation corresponding with Fig. 8.

As shown in figure 11, controller 64 is by constituting with lower member: the 1st reservoir 71, and it stores with the 1st pressure transducer 51 detected arms the cylinder bottom pressure value of oil hydraulic cylinder 11 and the relation of the instruction current value of the signal input part of supplying with the 1st and the 2nd solenoid valve 61,62; The 2nd reservoir 72, it stores with the first pilot (arm dropping signal) of the 2nd pressure transducer 63 detected first roddings 40 and the relation of the instruction current value of the signal input part of supplying with the 1st solenoid valve 62; Minimum value is selected loop 73, and it is selecting little instruction current value to supply with the signal input part of above-mentioned the 1st solenoid valve 62 from the instruction current value of above-mentioned the 1st reservoir 71 outputs with between the instruction current value of above-mentioned the 2nd reservoir 72 outputs.

And, adopt the words of this routine controller 64, in with the scope of pressure transducer 51 detected arms with the cylinder bottom pressure value of cylinder bottom pressure value when arm falls because of deadweight of oil hydraulic cylinder 11, promptly regulation is pressed the above occasion of P0, because from the instruction current value of the 1st reservoir 71 outputs is little value, thus the 1st solenoid valve 61 maintaining valve position 61a, in addition, select the little instruction current of loop 73 output values from minimum value, and irrelevant with the size of the instruction current of exporting from the 2nd reservoir 72.For this reason, also maintaining valve position 62a of the 2nd solenoid valve 62.Therefore, owing to the signal port of the pressure oil that sprays from pioneer pump 24 through the switching valve 262 of the 1st solenoid valve 61 and first rodding 65 supply flow control valves 26, so, switching valve 262 is switched to switching position 26a, and, oily owing to disconnected by the 2nd solenoid valve 62 from the pressure of pioneer pump 24 ejections, formerly 66 kinds of first pilots of rodding do not increase, center by-pass flow switching valve 27 maintaining valve position 27a.

On the other hand, with pressure transducer 51 detected arms with the cylinder bottom pressure value of oil hydraulic cylinder 11 in extruding force affacts the scope of cylinder bottom pressure value of occasion of arm 5, promptly press the lower pressure applications of P0 than regulation, because from the instruction current value of the 1st reservoir 71 outputs is big value, thereby the 1st solenoid valve 61 switches to switching position 61b.In addition, select loop 73 outputs and the corresponding electric current of exporting from the 2nd reservoir 72 of instruction current from minimum value.Therefore, when carrying out the arm down maneuver, the 2nd solenoid valve 62 switches to switching position 62b, and center by-pass flow switching valve 27 switches road switching position 27b.Conversely, in the occasion of not carrying out the arm step-down operation, because the 2nd solenoid valve 62 maintaining valve position 62a, so center by-pass flow switching valve 27 maintaining valve position 27a.

Switching valve 262 at flow control valve 26 is switched to switching position 26a, and the occasion of center by-pass flow switching valve 27 maintaining valve position 27a, as illustrating in the 1st embodiment, only the recovered oil of discharging from cylinder bottom chamber 11a is supplied with piston rod chamber 11b, arm 5 falls because of deadweight.And, in this occasion, utilize 30 pump control signal Xp1s suitable of shuttle valve group to output to modulating valve 21a with the fuel tank pressure, control reduces the discharge capacity of variable capacity hydraulic pump 21.On the other hand, be switched to switching position 61b, 62b respectively at the 1st solenoid valve 61 that constitutes lifting switching valve 25 and the valve position of the 2nd solenoid valve 62, and center by-pass flow switching valve 27 switches to the occasion of switching position 27b, as having illustrated among the 1st embodiment, owing to recovered oil with from pressure oil interflow and supply piston rod chamber 11b that variable capacity hydraulic pump 21 is supplied with, thus the strong extruding forces such as lifting power of generation car body.And, in this occasion, utilize shuttle valve group 30 to output to modulating valve 21a with the corresponding pump control signal Xp1 of maximal pressure that selects with shuttle valve group 30, control increases the discharge capacity of variable capacity hydraulic pump 21.

The hydraulic working machine of present embodiment also can play the effect same with the 7th embodiment's hydraulic working machine.

(the 9th example of oil hydraulic circuit)

Secondly, the 4th example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Figure 12.Figure 12 is the circuit diagram of the 9th embodiment's oil hydraulic circuit, from this figure as can be known, this routine oil hydraulic circuit is characterised in that, utilize the first pilot of the reduction valve 23b generation that constitutes pilot operated device 23, i.e. the switching of arm dropping signal travel direction control valve 22, flow control valve 26 and center by-pass flow switching valve 27.

In Figure 12, symbol 51 is to detect the 1st pressure transducer that arm is pressed with the cylinder bottom of oil hydraulic cylinder 11, symbol 81, the 82nd, the 1st and the 2nd solenoid valve of formation lifting switching valve, symbol 83 is that the output signal and the output of reading the 1st pressure transducer 51 are used to switch the 1st and the 2nd solenoid valve 81, the controller of the instruction current value of 82 switching position, symbol 84 is that before rodding 40 is told, the first rodding that is connected with the 1st solenoid valve 81, symbol 85 is that before rodding 40 is told, the first rodding that is connected with the 2nd solenoid valve 82, symbol 86 is the first roddings of signal port that connect the switching valve 262 of the 1st solenoid valve 81 and flow control valve 26, symbol 87 is the first roddings that connect the signal port of the 2nd solenoid valve 82 and center by-pass flow switching valve 27, symbol 88 is the first roddings that connect the reduction valve 23c that lift operations is used on the arm that the 2nd solenoid valve 82 and pilot operated device 23 possessed, symbol 89 is provided in a side of the one-way valve of the tie point of first rodding 87 and first rodding 88, in addition, for part with it the identical symbolic representation corresponding with Fig. 8.

As shown in figure 12, controller 83 is by constituting with lower member: the 1st reservoir 91, and it stores with the 1st pressure transducer 51 detected arms the cylinder bottom pressure value of oil hydraulic cylinder 11 and the relation of the instruction current value of the signal input part of supplying with the 1st solenoid valve 81; The 2nd reservoir 92, it stores with the 1st pressure transducer 51 detected arms the cylinder bottom pressure value of oil hydraulic cylinder 11 and the relation of the instruction current value of the signal input part of supplying with the 2nd solenoid valve 82.

And, adopt the words of this routine controller 83, in with the scope of pressure transducer 51 detected arms with the cylinder bottom pressure value of cylinder bottom pressure value when arm falls because of deadweight of oil hydraulic cylinder 11, promptly in the occasion of stipulating to press more than the P0, the 1st solenoid valve 81 utilizes from the instruction current value maintaining valve position 81a of the 1st reservoir 91 outputs, and the 2nd solenoid valve 82 utilizes from the instruction current value maintaining valve position 82a of the 2nd reservoir 92 outputs.Therefore, in the occasion of carrying out the arm step-down operation, before rodding 40 is supplied to the signal port of the switching valve 262 of flow control valve 26 through first rodding the 84, the 1st solenoid valve 81 and first rodding 86, because switching valve 262 is switched to switching position 26a, and first rodding 85 is disconnected by the 2nd solenoid valve 82, so, formerly rodding 87 first pilots are not set up, center by-pass flow switching valve 27 maintaining valve position 27a.

On the other hand, with pressure transducer 51 detected arms with the cylinder bottom pressure value of oil hydraulic cylinder 11 in extruding force acts on the scope of cylinder bottom pressure value of occasion of arm 5, promptly press the lower occasion of P0 than regulation, the 1st solenoid valve 81 utilizes from the instruction current value of the 1st reservoir 91 outputs and switches to switching position 81b, and the 2nd solenoid valve 82 utilizes from the instruction current value of the 2nd reservoir 92 outputs and switches to switching position 82b.Therefore, because first rodding 84 is disconnected by the 1st switching valve 81, so formerly rodding 84 is not set up first pilot, flow control valve 26 is switched to switching position 26b, and, become the state that first rodding 40 and first rodding 87 are communicated with.Therefore, carry out the words of arm step-down operation, because descending, arm is supplied to the signal port of center by-pass flow switching valve 27 by first rodding 40, first rodding the 85, the 2nd solenoid valve 82 and first rodding 87, so center by-pass flow switching valve 27 is switched to switching position 27b with first pilot.

Switching valve 262 at flow control valve 26 is switched to switching position 26a, and center by-pass flow switching valve 27 is switched to the occasion of switching position 27a, as the 1st embodiment illustrated, only the recovered oil of discharging from cylinder bottom chamber 11a is supplied with piston rod chamber 11b, arm 5 falls because of deadweight.And, in this occasion, utilize 30 pump control signal Xp1s suitable of shuttle valve group to output to modulating valve 21a with the fuel tank pressure, control reduces the discharge capacity of variable capacity hydraulic pump 21.On the other hand, be switched to switching position 81b, 82b at the 1st solenoid valve 81 and the 2nd solenoid valve 82 that constitute lifting switching valve 25, and center by-pass flow switching valve 27 switches to the occasion of switching position 27b, as having illustrated among the 1st embodiment, owing to recovered oil with from pressure oil interflow and supply piston rod chamber 11b that variable capacity hydraulic pump 21 is supplied with, thus the strong extruding forces such as lifting power of generation car body.And, in this occasion, utilize shuttle valve group 30 will with output to modulating valve 21a with the corresponding pump control signal Xp1 of the maximal pressure of shuttle valve group 30 choices, control increases the discharge capacity of variable capacity hydraulic pump 21.

The hydraulic working machine of present embodiment also plays the effect same with the 7th embodiment's hydraulic working machine.

(the 10th example of oil hydraulic circuit)

Secondly, the 10th example of the oil hydraulic circuit that above-mentioned hydraulic working machine possesses is described with Figure 13 and Figure 14.Figure 13 is the circuit diagram of the 10th embodiment's oil hydraulic circuit, Figure 14 is the structural drawing of the 10th embodiment's the shuttle valve group that oil hydraulic circuit possessed, by these figure as can be known, this routine oil hydraulic circuit is characterised in that, traveling gear is driven with oil hydraulic circuit and arm driving make up with oil hydraulic circuit.

In Figure 13, symbol 8 is right lateral fluid pressure motors, symbol 9 is left lateral fluid pressure motors, symbol 101 is the 2nd variable capacity hydraulic pumps, symbol 102 is that control is supplied with 2nd position control valve of right lateral with the flow direction of the pressure oil of fluid pressure motor 8 from variable capacity hydraulic pump 21, symbol 103 is that control is supplied with 3rd position control valve of left lateral with the flow direction of the pressure oil of fluid pressure motor 9 from the 2nd variable capacity hydraulic pump 101, symbol 104 is to supply with 4th position control valve of arm with the flow direction of the pressure oil of oil hydraulic cylinder 11 from the 2nd variable capacity hydraulic pump 101 when being controlled at the arm down maneuver, be used for the switching valve of the Pressure oil feeder left lateral of supplying with from the 1st variable capacity hydraulic pump 21 in the occasion of carrying out the arm step-down operation during symbol 105 with fluid pressure motor 9 sides, symbol 106 is in the occasion of carrying out the arm operation, switching signal is given the shuttle valve of switching valve 105, symbol 107 is the oil ducts that are communicated with the 2nd variable capacity hydraulic pump 101 and the 4th direction switching valve 104, symbol 108 is the center by-pass flow paths that are communicated with the 2nd variable capacity hydraulic pump 101 and fuel tank 28, symbol 109 is oil ducts that connection the 4th direction switching valve 104 and arm are used the piston rod chamber 11b of oil hydraulic cylinder 11, symbol 110 is oil ducts that connection the 4th direction switching valve 104 and arm are used the cylinder bottom chamber 11a of oil hydraulic cylinder 11, symbol 111 is provided in a side of the one-way valve on the oil duct 110, symbol 112 is the oil ducts that connect variable capacity hydraulic pump 21 and switching valve 105, symbol 113 is provided in a side of the one-way valve of oil duct 112, symbol 114 is the oil ducts that connect switching valve 105 and the 3rd position control valve 103, symbol 115 is the first rodding of the first pilot guiding lifting switching valve 25 that becomes the arm dropping signal, symbol 116 is first roddings of the arm dropping signal being supplied with the signal port of the 4th position control valve 104, symbol 117 is first roddings of the arm rising signals being supplied with the signal port of the 4th position control valve 104, symbol 118 is first roddings of switching signal being supplied with the signal port of switching valve 105, in addition, part with it the identical symbolic representation corresponding with Fig. 8.

In addition, as shown in figure 14, the shuttle valve group 30 that the oil hydraulic circuit that this is routine possessed is the structure of additional shuttle valve 316 and hydraulic pressure switching valve 319 on the shuttle valve group of Fig. 9.Shuttle valve 316 is configured in the 6th section of shuttle valve group 30, selects the high pressure side of the operation signal pressure selected separately with the shuttle valve 302 of epimere and the 3rd section shuttle valve 312.In addition, hydraulic pressure switching valve 319 is that the maximum pressure of selecting with shuttle valve 316 is directed to compression zone 319a, based on its maximum pressure work, produces the proportional pressure-reducing valve of control signal pressure (pump control signal Xp2) from the pressure of pioneer pump 24.This hydraulic pressure switching valve 319, at the maximum pressure of selecting with shuttle valve 316 when tank pressure is following, in illustrated position and make control signal pressure be reduced to fuel tank to press, the maximum pressure of selecting with shuttle valve 316 is when tank pressure is above, be switched from illustrated position, the pressure of pioneer pump 24 reduced pressure and the horizontal control signal corresponding pressure of this maximum pressure and output.The modulating valve 101a of the 2nd variable capacity hydraulic pump 101 utilizes this control signal pressure (pump control signal Xp2) work.

Below, the action of the 10th embodiment's that as above constitutes hydraulic working machine is described.

As shown in figure 13, in the occasion of operating stem 23a in the neutral position, position control valve 22 and the 4th position control valve 104 maintain a neutral position separately 22b and neutral position 104b, lifting switching valve 25 switches to switching position 25a because of arm with the pressure of the cylinder bottom side of oil hydraulic cylinder 11.At this state, first rodding 43 is communicated with fuel tank 28, center by-pass flow switching valve 27 maintaining valve position 27a, switching valve 105 maintaining valve position 105a.Therefore, be directed to fuel tank 28 from the pressure oil of variable capacity hydraulic pump 21 ejections through center by-pass flow mouth, oil duct 37, center by-pass flow switching valve 27 and the oil duct 38 of oil channel 31, position control valve 22, in addition, owing to be directed to fuel tank 28 through the center by-pass flow mouth of oil channel 107, oil duct the 108, the 3rd position control valve 103, press oil not to be supplied to cylinder bottom chamber 11a and the piston rod chamber 11b of arm with oil hydraulic cylinder 11 from the pressure oil of the 2nd variable capacity hydraulic pump 101 ejections.

From this state to illustrated left to, i.e. arm descent direction operating operation bar 23a, 24 that supply with from pioneer pump, be depressurized the first pilot that valve 23b reduced pressure and exported to first rodding 40, position control valve 22 is switched to switching position 22a.On the other hand, because this elder generation's pilot is directed to first rodding 115, process lifting switching valve 25 is directed to the signal port of switching valve 262, so switching valve 262 is switched to switching position 26a.Like this, through throttling 29b, one-way valve 29c and oil duct 35 and at piston rod chamber 11b, and the remaining oil that returns returns fuel tank 28 through throttling 29a and oil duct 39 from the part of returning oil of cylinder bottom chamber 11a.

In this occasion, when the working pressure of cylinder bottom pressure ratio lifting switching valve 25 is higher, because lifting switching valve 25 maintains valve position 25a, so, the switching position of flow control valve 26 also maintains switching position 26a, and in addition, center by-pass flow switching valve 27 also maintains valve position 27a.Therefore, from the pressure oil of variable capacity hydraulic pump 21 ejection through oil channel 31, the center by-pass flow mouth of position control valve 22, oil duct 37, center by-pass flow switching valve 27 and oil duct 38 and be directed to fuel tank 28, in addition, oily from the pressure of the 2nd variable capacity hydraulic pump 101 ejections because through oil channel 107, oil duct 108, the center by-pass flow mouth of the 3rd position control valve 103 and be directed to fuel tank 28, so, press oil not to be supplied to cylinder bottom chamber 11a and the piston rod chamber 11b of arm with oil hydraulic cylinder 11, only the recovered oil of discharging from cylinder bottom chamber 11a is supplied to piston rod chamber 11b, utilize the deadweight of arm 5, arm dwindles with oil hydraulic cylinder 11, and arm 5 falls because of deadweight.

When arm 5 deadweights fell, the pressure oil that produces with pilot operated device 23 did not enter the lifting signal input G of shuttle valve group 30, enters arm dropping signal inlet opening Dd.The pressure of lifting signal input G is being selected other a plurality of operation signals and maximal pressure and is being switched to hydraulic pressure switching valve 317 but do not have operated occasion at not shown other pilot operated devices that go out, and hydraulic pressure switching valve 317 is not switched, and keeps the state of Fig. 4.Like this, fuel tank is pressed and is output from shuttle valve group 30 as pump control signal Xp1, Xp2, through modulating valve 21a, 101a control variable capacity hydraulic pump 21,101 minimizing capacity.

On the other hand, in the occasion of operating stem 23a to the operation of arm descent direction, when the working pressure of cylinder bottom pressure ratio lifting switching valve 25 is lower, because lifting switching valve 25 ripples switch to switching position 25b, so first rodding 45 is communicated with fuel tank 28 through lifting switching valve 25, the switching valve 262 of flow control valve 26 is switched to valve position 26b.Therefore, be supplied to the inlet restriction mouth of position control valve 22 through oil channel 32, flow control valve 26, oil duct 33 from the pressure oil of variable capacity hydraulic pump 21 ejections.In addition, be accompanied by the switching of lifting switching valve 25, owing to be supplied to the signal port of center by-pass flow switching valve 27 through first rodding 115, lifting switching valve 25, first rodding 43 as the first pilot of arm dropping signal, so, center by-pass flow switching valve 27 is switched to switching position 27b, and, because the first rodding 116 of process is supplied to the signal port of the arm decline side of the 4th position control valve 104, so the 4th position control valve 104 is switched to switching position 104a.Therefore, be supplied to the piston rod chamber 11b of arm from the pressure oil of variable capacity hydraulic pump 21 ejections with oil hydraulic cylinder 11, and, be supplied to the piston rod chamber 11b of arm from the pressure oil of the 2nd variable capacity hydraulic pump 101 ejections through the 4th position control valve 104, oil duct 109 and oil duct 35 with oil hydraulic cylinder 11, the pressure oil of supplying with owing to the recovered oil of discharging with from variable capacity hydraulic pump 21 and be supplied to piston rod chamber 11b from the pressure oil interflow that the 2nd variable capacity hydraulic pump 101 is supplied with from cylinder bottom chamber 11a, thus the strong extruding force of the lifting power etc. of car body can be produced.

When lifting, the pressure oil that produces on guide's operation equipment 23 enters the lifting signal input G of shuttle valve group 30, selects other a plurality of signals and maximal pressure and switches hydraulic pressure switching valve 317.Like this, export from shuttle valve group 30 as pump control signal Xp1, Xp2, through modulating valve 21a, 101a control variable capacity hydraulic pump 21,101 increase capacity with the corresponding pressure of above-mentioned maximal pressure.

In addition, because the arm operation is directed to switching valve 105 with first pilot through shuttle valve 106, oil duct 118, so, switching valve 105 is switched to switching position 105b, and the pressure oil that sprays from variable capacity hydraulic pump 21 is supplied to walking fluid pressure motor 8,9 about each through the 2nd position control valve 102 and the 3rd position control valve 103.Like this, when operating arm and walking at the same time, because the walking motor 8,9 about being supplied to from the pressure oil of variable capacity hydraulic pump 21, pressure oil from the 2nd variable capacity hydraulic pump 101 is supplied to arm oil hydraulic cylinder 11, so the lifting of the car body of the composite move of feasible walking operation and arm down maneuver becomes possibility.

In addition, in above-mentioned the 10th embodiment, use hydraulic pilot formula switching valve as lifting switching valve 25, but same with above-mentioned the 7th to the 9th embodiment's hydraulic working machine, also can use electromagnetism hydraulic type or electromagnetic type switching valve.

In addition, in the various embodiments described above, is that example is illustrated to be used to drive arm with the oil hydraulic circuit of oil hydraulic cylinder 11, but main idea of the present invention is not limited thereto, and also can adopt and above-mentioned same structure the oil hydraulic circuit that is used to drive the oil hydraulic cylinder that other job factors use.

Claims (24)

1. hydraulic working machine, it possesses: utilize the dbl act oil hydraulic cylinder that stretches, drives job factor from the pressure oil of main pump ejection; The position control valve flow direction, that have center by-pass flow mouth of the pressure oil of above-mentioned oil hydraulic cylinder, the operation equipment that carries out the handover operation of this position control valve are supplied with in control from above-mentioned main pump,

It is characterized in that possessing: when the supply pressure to above-mentioned oil hydraulic cylinder reaches the regulation pressure, the lifting switching valve that stream is switched; The handover operation of following this switching valve is altered to the stream shifting mechanism of open circuit side or closed circuit side to the stream of the pressure oil of the inlet restriction of above-mentioned position control valve being supplied with from above-mentioned main pump,

When above-mentioned job factor down maneuver, the maintenance of above-mentioned oil hydraulic cylinder is pressed in afore mentioned rules and presses when above, above-mentioned lifting switching valve is switched to the 1st switching position, above-mentioned stream shifting mechanism is switched to closed circuit side, even switch above-mentioned position control valve on descent direction so that above-mentioned job factor moves, supply side is not pressed in the non-maintenance of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from above-mentioned main pump yet, but allow and press oil to flow to the center of above-mentioned position control valve by-pass flow mouth

When above-mentioned job factor down maneuver, when the maintenance pressure of above-mentioned oil hydraulic cylinder does not arrive the afore mentioned rules pressure, above-mentioned lifting switching valve is switched to the 2nd switching position, above-mentioned stream shifting mechanism is switched to the open circuit side, side is pressed in the non-maintenance of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from above-mentioned main pump through above-mentioned position control valve.

2. hydraulic working machine, it possesses: main pump; Job factor; The dbl act oil hydraulic cylinder of above-mentioned job factor is stretched, drives in utilization from the pressure oil of above-mentioned main pump ejection; The position control valve flow direction, that have center by-pass flow mouth of the pressure oil of the cylinder bottom chamber of above-mentioned oil hydraulic cylinder and piston rod chamber is supplied with in control from above-mentioned main pump; Carry out the operation equipment of the handover operation of this position control valve,

It is characterized in that possessing: press at the cylinder bottom of above-mentioned oil hydraulic cylinder to reach the lifting switching valve that switches when regulation is pressed; Be accompanied by the handover operation of this lifting switching valve, the stream of the pressure oil of the inlet restriction of above-mentioned position control valve being supplied with from above-mentioned main pump transformed to the stream shifting mechanism of open circuit side or closed circuit side,

When above-mentioned job factor down maneuver, being pressed in afore mentioned rules at the cylinder bottom of above-mentioned oil hydraulic cylinder presses when above, above-mentioned lifting switching valve is switched to the 1st switching position and makes above-mentioned stream shifting mechanism switch to closed circuit side, even switch above-mentioned position control valve on descent direction so that above-mentioned job factor moves, also not the piston rod chamber of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from above-mentioned main pump, but allow and press oil to flow to the center of above-mentioned position control valve by-pass flow mouth

When above-mentioned job factor down maneuver, when the cylinder bottom pressure of above-mentioned oil hydraulic cylinder does not arrive the afore mentioned rules pressure, above-mentioned lifting switching valve is switched to the 2nd switching position and makes above-mentioned stream shifting mechanism switch to the open circuit side, and the above-mentioned position control valve of process is the piston rod chamber of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from above-mentioned main pump.

3. a hydraulic working machine possesses: the 1st and the 2nd main pump; The 1st traveling gear that the pressure oil that is sprayed from above-mentioned the 1st main pump drives; The 2nd traveling gear that the pressure oil that is sprayed from above-mentioned the 2nd main pump drives; The 1st position control valve of the flow direction of the pressure oil of above-mentioned the 1st traveling gear is supplied with in control from above-mentioned the 1st main pump; The 2nd position control valve of the flow direction of the pressure oil of above-mentioned the 2nd traveling gear is supplied with in control from above-mentioned the 2nd main pump; Job factor; The dbl act oil hydraulic cylinder of above-mentioned job factor is stretched, drives in utilization from the pressure oil of the above-mentioned the 1st and the 2nd main pump ejection; The 3rd position control valve flow direction, that have center by-pass flow mouth of the pressure oil of the cylinder bottom chamber of above-mentioned oil hydraulic cylinder and piston rod chamber is supplied with in control from above-mentioned the 1st main pump; The 4th position control valve of the flow direction of the pressure oil of the cylinder bottom chamber of above-mentioned oil hydraulic cylinder and piston rod chamber is supplied with in control from above-mentioned the 2nd main pump; Carry out the above-mentioned the 1st and the 1st operation equipment of the handover operation of the 2nd position control valve; Carry out the above-mentioned the 3rd and the 2nd operation equipment of the handover operation of the 4th position control valve,

It is characterized in that possessing: press at the cylinder bottom of above-mentioned oil hydraulic cylinder to reach the lifting switching valve that switches when regulation is pressed; The handover operation that is accompanied by this lifting switching valve transforms to the stream shifting mechanism of open circuit side or closed circuit side to the stream of the pressure oil of the inlet restriction of above-mentioned the 3rd position control valve being supplied with from above-mentioned the 1st main pump,

When above-mentioned job factor down maneuver, being pressed in afore mentioned rules at the cylinder bottom of above-mentioned oil hydraulic cylinder presses when above, above-mentioned lifting switching valve is switched to the 1st switching position and makes above-mentioned stream shifting mechanism switch to closed circuit side, even switch above-mentioned position control valve on descent direction so that above-mentioned job factor moves, also not the piston rod chamber of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from the above-mentioned the 1st and the 2nd main pump, but allow and press oil to flow to the center of above-mentioned position control valve by-pass flow mouth

When above-mentioned job factor down maneuver, when the cylinder bottom pressure of above-mentioned oil hydraulic cylinder does not arrive the afore mentioned rules pressure, above-mentioned lifting switching valve is switched to the 2nd switching position and makes above-mentioned stream shifting mechanism switch to the open circuit side, and process the above-mentioned the 3rd and the 4th position control valve is the piston rod chamber of the above-mentioned oil hydraulic cylinder of Pressure oil feeder that sprays from the above-mentioned the 1st and the 2nd main pump.

4. according to claim 2 or 3 described hydraulic working machines, it is characterized in that,

Possesses the regenerative circuit of inlet restriction oil of a part of regeneration of the outlet throttling oil of discharging from the cylinder bottom chamber of above-mentioned oil hydraulic cylinder being supplied with the piston rod chamber of above-mentioned oil hydraulic cylinder.

5. according to any described hydraulic working machine in the claim 1 to 3, it is characterized in that possessing hydraulic pilot formula switching valve as above-mentioned lifting switching valve.

6. hydraulic working machine according to claim 1 is characterized in that,

Above-mentioned main pump is the variable capacity type oil hydraulic pump, and this hydraulic working machine also possesses: the control mechanism that verts of controlling this variable capacity type hydraulic pressure pump delivery; And according to from the signal of the aforesaid operations device indicating device of verting to the above-mentioned control mechanism output tilt control signal that verts,

When the down maneuver of above-mentioned job factor; Being pressed in afore mentioned rules in the maintenance of above-mentioned hydraulic cylinder presses when above; Above-mentioned lifting transfer valve is switched to the 1st switching position and makes above-mentioned stream mapping device switch to closed circuit side; Even switch above-mentioned directional control valve so that above-mentioned job factor moves at descent direction; Also disconnect the force feed of supplying with above-mentioned hydraulic cylinder from above-mentioned variable capacity type hydraulic pump; And; Control reduces above-mentioned variable capacity type hydraulic pressure pump delivery; Allow that force feed flows to the center by-pass flow mouth of above-mentioned directional control valve

When the down maneuver of above-mentioned job factor, when the maintenance of above-mentioned oil hydraulic cylinder presses the end to press to afore mentioned rules, above-mentioned lifting switching valve is switched to the 2nd switching position and makes above-mentioned stream shifting mechanism switch to the open circuit side, the above-mentioned position control valve of process is the above-mentioned oil hydraulic cylinder of Pressure oil feeder from above-mentioned variable capacity type oil hydraulic pump ejection, and, utilize the above-mentioned indicating device's control of verting to increase above-mentioned variable capacity type hydraulic pressure pump delivery.

7. hydraulic working machine according to claim 3 is characterized in that,

The the above-mentioned the 1st and the 2nd main pump is the 1st and the 2nd variable capacity type oil hydraulic pump, and this hydraulic working machine also possesses: control the 1st and the 2nd of the 1st and the 2nd variable capacity type hydraulic pressure pump delivery control mechanism that verts respectively; And according to from the signal of above-mentioned the 1st operation equipment indicating device of verting to the above-mentioned control mechanism output tilt control signal that verts,

When the down maneuver of above-mentioned job factor; Being pressed in afore mentioned rules in the maintenance of above-mentioned hydraulic cylinder presses when above; Above-mentioned lifting transfer valve is switched to the 1st switching position and make above-mentioned stream mapping device switch to closed circuit side; Even switch above-mentioned directional control valve so that above-mentioned job factor moves at descent direction; Also disconnect the force feed of supplying with above-mentioned hydraulic cylinder from the above-mentioned the 1st and the 2nd variable capacity type hydraulic pump; And; Control reduces by the above-mentioned the 1st and the 2nd variable capacity type hydraulic pressure pump delivery; Allow that force feed flows to the center by-pass flow mouth of above-mentioned directional control valve

When the down maneuver of above-mentioned job factor, when the maintenance pressure of above-mentioned oil hydraulic cylinder does not arrive the afore mentioned rules pressure, above-mentioned lifting switching valve is switched to the 2nd switching position and above-mentioned stream shifting mechanism is switched to the open circuit side, through the above-mentioned the 3rd and the 4th position control valve the above-mentioned oil hydraulic cylinder of Pressure oil feeder from the ejection of the above-mentioned the 1st and the 2nd variable capacity type oil hydraulic pump, and, utilize the above-mentioned indicating device's control of verting to increase by the above-mentioned the 1st and the 2nd variable capacity type hydraulic pressure pump delivery.

8. according to any described hydraulic working machine in the claim 1,2 and 6, it is characterized in that,

Above-mentioned stream shifting mechanism comprises: the upstream side at above-mentioned position control valve is connected with the inlet restriction mouth of this position control valve, switch to closed circuit position when above-mentioned lifting switching valve switches to the 1st switching position, switch to the flow control valve of open-circuit position when above-mentioned lifting switching valve switches to the 2nd switching position;

Downstream side at above-mentioned position control valve is connected with the center by-pass flow mouth of this position control valve, switch to the open-circuit position when above-mentioned lifting switching valve switches to the 1st switching position, switch to the center by-pass flow switching valve of closed circuit position when above-mentioned lifting switching valve switches to the 2nd switching position.

9. according to claim 3 or 7 described hydraulic working machines, it is characterized in that,

Above-mentioned stream shifting mechanism comprises: the upstream side at above-mentioned the 3rd position control valve is connected with the inlet restriction mouth of the 3rd position control valve, switch to closed circuit position when above-mentioned lifting switching valve switches to the 1st switching position, switch to the flow control valve of open-circuit position when above-mentioned lifting switching valve switches to the 2nd switching position;

Downstream side at above-mentioned the 3rd position control valve is connected with the center by-pass flow mouth of above-mentioned the 3rd position control valve, switch to the open-circuit position when above-mentioned lifting switching valve switches to the 1st switching position, switch to the center by-pass flow switching valve of closed circuit position when above-mentioned lifting switching valve switches to the 2nd switching position.

10. according to claim 6 or 7 described hydraulic working machines, it is characterized in that,

Possess hydraulic pilot formula switching valve as above-mentioned lifting switching valve, possess throttling in the pilot port of this hydraulic pilot formula switching valve.

11. hydraulic working machine according to claim 8 is characterized in that,

Possess hydraulic pilot formula switching valve as above-mentioned lifting switching valve, possess throttling in the pilot port of this hydraulic pilot formula switching valve.

12. hydraulic working machine according to claim 9 is characterized in that,

Possess hydraulic pilot formula switching valve as above-mentioned lifting switching valve, possess throttling in the pilot port of this hydraulic pilot formula switching valve.

13. according to any described hydraulic working machine in the claim 1 to 3, it is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

14. hydraulic working machine according to claim 4 is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

15. hydraulic working machine according to claim 5 is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

16. according to claim 6 or 7 described hydraulic working machines, it is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

17. hydraulic working machine according to claim 8 is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

18. hydraulic working machine according to claim 9 is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

19. hydraulic working machine according to claim 10 is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

20. hydraulic working machine according to claim 11 is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

21. hydraulic working machine according to claim 12 is characterized in that,

Also possess: control the switch motion of above-mentioned lifting switching valve the electromagnetic type switching valve, detect above-mentioned oil hydraulic cylinder the cylinder bottom chamber force value Pressure testing mechanism, according to the electric control mechanism that makes above-mentioned electromagnetic type switching valve action by the detected pressure of above-mentioned Pressure testing mechanism.

22. according to claim 6 or 7 described hydraulic working machines, it is characterized in that,

The above-mentioned indicating device of verting is made of the combination of a plurality of shuttle valves of the maximum pressure of the operation signal pressure group of selecting regulation among the operation signal pressure that utilizes above-mentioned pilot operated device to produce.

23. hydraulic working machine according to claim 6 is characterized in that,

The job factor of above-mentioned down maneuver is an arm, and above-mentioned actuator is the arm oil hydraulic cylinder.

24. hydraulic working machine according to claim 22 is characterized in that,

Possess supplying with the regenerative circuit of above-mentioned arm with a part of regeneration of the outlet throttling oil of the cylinder bottom chamber discharge of oil hydraulic cylinder with the inlet restriction oil of the piston rod chamber of oil hydraulic cylinder from above-mentioned arm.

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