JP2017077966A - Work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work machine that can effectively utilize hydraulic oil in a hydraulic oil circuit without an increase in a size of a device.SOLUTION: A hydraulic pump motor 43 is driven by the hydraulic oil that flows out from a lifting cylinder 41 on which weight of a counterweight W acts when the counterweight W moves downward, whereby, the hydraulic pump motor 43 can be driven without a need of an accumulator. Thus, the hydraulic oil in the hydraulic oil circuit 42 can be effectively utilized without an increase in the size of the device.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a work machine such as a mobile crane.

  Conventionally, this type of work machine includes an actuator that drives a work device, a hydraulic pump that supplies hydraulic oil to the actuator, an engine that drives the hydraulic pump, and an operation that connects the actuator and the hydraulic pump. An accumulator provided in an oil circuit is known (see, for example, Patent Document 1).

  In the work machine, a hydraulic pump motor having a function of a hydraulic motor is used as the hydraulic pump, and when starting the stopped engine, the hydraulic pump motor connected to the engine is driven by hydraulic oil stored in the accumulator. By doing so, the load of the cell motor and the battery when starting the engine is reduced.

JP 2013-91953 A

  In the work machine, in order to increase the driving time of the hydraulic pump motor that uses hydraulic oil stored in the accumulator as a power source, it is necessary to connect a large accumulator to the hydraulic oil circuit. However, since the working machine has a limited space for installing an accumulator, it is impossible to install an accumulator having a required capacity.

  An object of the present invention is to provide a work machine that can effectively use the hydraulic oil in the hydraulic oil circuit without increasing the size of the apparatus.

  In order to achieve the above object, the present invention provides a counterweight, an elevating actuator for moving the counterweight in the vertical direction, a hydraulic fluid circuit connected to the elevating actuator, and a counterweight being moved downward by the elevating actuator. And an actuator driving means for driving another actuator connected to the hydraulic oil circuit by the hydraulic oil flowing out from the lifting actuator due to the weight of the counterweight.

  As a result, the weight of the counterweight acts to drive other actuators with the hydraulic oil flowing out from the lifting actuator, so that it is possible to drive other actuators without requiring an accumulator. .

  According to the present invention, it is possible to drive other actuators without requiring an accumulator, so that the hydraulic oil in the hydraulic oil circuit can be effectively used without increasing the size of the device. Become.

It is a side view of the mobile crane which shows one Embodiment of this invention. It is the figure which looked at the turntable which shows the connection method of a turntable and a counterweight from back. It is the figure which looked at the turntable which shows the state where the counterweight was attached with respect to the turntable from back. It is a schematic block diagram of a counterweight raising / lowering apparatus. It is a block diagram which shows a control system. It is a flowchart which shows an engine stop control process. It is a flowchart which shows an engine starting control process. It is a schematic block diagram of the counterweight raising / lowering apparatus which shows other embodiment of this invention.

  1 to 7 show an embodiment of the present invention.

  As shown in FIG. 1, a mobile crane 1 as a work machine according to the present invention is capable of turning in a horizontal direction with respect to a lower traveling body 10 for traveling on a general road or a work area, and a lower traveling body. And an upper revolving body 20 provided.

  The lower traveling body 10 includes wheels 11 provided on both sides in the width direction on the front side and the rear side of the carrier frame extending in the front-rear direction, outriggers 12 provided on both sides in the width direction on the front end portion and the rear end portion of the carrier frame, It has. The lower traveling body 10 travels using the engine E as a power source, and the jack cylinder of the outrigger 12 is driven by hydraulic oil discharged from a hydraulic pump motor (described later) that is driven by the power of the engine E transmitted through the PTO mechanism. To do.

  The upper turning body 20 is provided so as to be turnable with respect to the lower traveling body 10 via a ball bearing type or roller bearing type turning circle 30. The upper turning body 20 performs a turning operation on the lower traveling body 10 so that the turning direction can be switched by a turning motor driven by hydraulic oil discharged from the hydraulic pump motor.

  The upper swivel body 20 is provided with a swivel base 21 fixed to the swivel circle 30, a crane device 22 provided at the back of the swivel base 21, and provided in front of the swivel base 21 for performing operations related to the crane device 22. And a cab 23.

  Further, in the mobile crane 1, a counterweight W is detachably attached to the rear portion of the swivel base 21 in order to ensure stability when a load is suspended from the tip of the boom of the crane device 22.

  When the counterweight W is attached to the rear part of the swivel base 21, first, the counterweight W is suspended and moved by the crane device 22, and the counterweight W is placed slightly on the front side in the center in the front-rear direction of the lower traveling body 10. To do. Next, as shown in FIG. 2, the swivel base 21 is swung so that the rear portion of the swivel base 21 faces the counterweight W placed on the lower traveling body 10. In this state, the support base 21 a extending backward from the rear portion of the swivel base 21 and the counterweight W are connected. The rear portion of the swivel base 21 and the counterweight W are connected via an elevating cylinder 41 of a counterweight elevating device 40 described later, as indicated by a two-dot chain line in FIG. Finally, lifting the counterweight W from the lower traveling body 10 by the elevating cylinder 41 completes the attachment of the counterweight W to the swivel base 21 as shown in FIG.

  The counterweight lifting / lowering device 40 is for moving the counterweight W in the vertical direction with respect to the swivel base 21. As shown in FIG. A hydraulic oil circuit 42 for supplying the oil.

  The elevating cylinder 41 has a cylindrical cylinder tube 41a whose one end face is closed, and a piston rod 41b that is movably provided in the cylinder tube 41a. In the elevating cylinder 41, the end of the piston rod 41b is detachably connected to the support base 21a of the swivel base 21, and the bottom end of the cylinder tube 41a is connected to the counterweight W. On the outer peripheral surface in the vicinity of the bottom of the cylinder tube 41a, there is provided an extension side hydraulic oil inlet 41c through which hydraulic oil flows when the elevating cylinder 41 is extended. A reduction-side hydraulic oil inlet 41d through which hydraulic oil flows when the elevating cylinder 41 is reduced is provided on the outer peripheral surface of the cylinder tube 41a near the end on the piston rod 41b side.

  The hydraulic oil circuit 42 is connected to a hydraulic pump motor 43 as another actuator that functions as a hydraulic pump by the power of the engine E and also has a function as a hydraulic motor. The hydraulic oil inflow side of the hydraulic pump motor 43 is a hydraulic oil tank. 44. The hydraulic oil outflow side of the hydraulic pump motor 43 is connected to the P port of the electromagnetic direction switching valve 45. A hydraulic oil tank 44 is connected to a T port of the direction switching valve 45. The A port of the direction switching valve 45 is connected to a reduction-side hydraulic oil inlet 41d of the cylinder tube 41a. An extension side hydraulic oil inlet 41c of the cylinder tube 41a is connected to the B port of the direction switching valve 45. In the hydraulic oil flow path between the A port of the direction switching valve 45 and the reduction-side hydraulic oil inlet 41d of the cylinder tube 41a, the hydraulic oil flowing from the reduction-side hydraulic oil inlet 41d to the A port of the direction switching valve 45 is supplied. A check valve 46 is provided for restricting the flow. In the check valve 46, the hydraulic fluid passage is opened by the pressure of the hydraulic fluid passage between the B port of the direction switching valve 45 and the extension hydraulic fluid inlet 41c of the cylinder tube 41a, and the reduced hydraulic fluid flow. This is a pilot type check valve that allows the hydraulic oil to flow from the inlet 41d toward the A port of the direction switching valve 45.

  Further, in the hydraulic oil circuit 42, the weight of the counterweight W acts to cause the hydraulic oil flowing out from the reduction-side hydraulic oil inlet 41d of the cylinder tube 41a to flow to the hydraulic oil inflow side of the hydraulic pump motor 43. The pump motor drive channel 47 is provided.

  The pump motor drive channel 47 connects the hydraulic fluid channel between the check valve 46 and the reduction-side hydraulic fluid inlet 41d and the hydraulic fluid channel on the hydraulic fluid inflow side of the hydraulic pump motor 43. It is. The end of the pump motor drive flow path 47 on the hydraulic pump motor 43 side is a flow path switch for switching the hydraulic oil flow path on the hydraulic oil inflow side of the hydraulic pump motor 43 to the hydraulic oil tank 44 or the pump motor drive flow path 47. The hydraulic fluid is connected to a hydraulic fluid passage on the hydraulic fluid inflow side of the hydraulic pump motor 43 via a valve 48.

  Further, the output shaft of the engine E and the input / output shaft of the hydraulic pump motor 43 are configured to be switchable between a state where the clutch 49 is connected (ON) and a state where the connection is released (OFF).

  The engine E can be started by applying the rotational force of the electric starter motor 50 to the output shaft.

  The mobile crane 1 also includes a controller 60 for controlling the operation of the engine during traveling and crane work. When the controller 60 receives an input signal from a device connected to the input side, the CPU reads a program stored in the ROM based on the input signal, and stores a state detected by the input signal in the RAM. The output signal is transmitted to a device connected to the output side.

  As shown in FIG. 5, the input side of the controller 60 is stopped by a height detection sensor 61 as a height detection means for detecting the height position of the counterweight W in the vertical direction and an idling stop function described later. An engine start switch 62 for inputting an operation for starting the engine E is connected to the engine E. Further, the direction switching valve 45, the flow path switching valve 48, the clutch 49, the starter motor 50, and the engine E are connected to the output side of the controller 60.

  In the mobile crane 1 configured as described above, the controller 60 can stop the engine E by an idling stop function as an engine stop means during crane operation.

  The idling stop function is to stop the engine E when a predetermined stop condition for stopping the engine E is satisfied, for example, a state where the operation lever operated by the operator is not operated during crane work for a predetermined time or longer.

  On the other hand, the engine E stopped by the idling stop function is started when the operator operates the engine start switch 62. At this time, the engine E can be started using only the driving force of the starter motor 50. Further, the engine E can be started using the driving force of the starter motor 50 and the hydraulic oil flowing out of the elevating cylinder 41 by moving the counterweight W downward.

  When the hydraulic oil pressure flowing out from the lifting cylinder 41 is used for starting the engine E, the clutch 49 is turned on and the flow path of the flow path switching valve 48 is set on the pump motor drive flow path 47 side. To do. As a result, the hydraulic oil in the elevating cylinder 41 flows out from the reduced-side hydraulic oil inlet 41d of the elevating cylinder 41 due to the weight of the counterweight W moving downward, and flows through the pump motor drive channel 47. The fluid passes through the hydraulic pump motor 43 and rotates the input / output shaft of the hydraulic pump motor 43. The rotational force of the input / output shaft of the hydraulic pump motor 43 at this time is added to the output shaft of the engine E together with the driving force of the starter motor 50.

  Further, the controller 60 performs an engine stop control process for making the hydraulic oil stored in the elevating cylinder 41 available when the engine E is started when the engine E is stopped by the idling stop function. The operation of the CPU of the controller 60 at this time will be described using the flowchart of FIG.

(Step S1)
In step S1, the CPU determines whether a stop condition for the engine E is satisfied. If it is determined that the engine E stop condition is satisfied, the process proceeds to step S2, and if it is not determined that the engine E stop condition is satisfied, the engine stop control process is terminated.

(Step S2)
If it is determined in step S1 that the stop condition of the engine E is satisfied, in step S2, the CPU determines whether the height position of the counterweight W is equal to or greater than a predetermined height based on the detection signal of the height detection sensor 61. Determine whether or not. If it is determined that the height position of the counterweight W is greater than or equal to the predetermined height, the process proceeds to step S3, and if it is not determined that the height position of the counterweight W is greater than or equal to the predetermined height. Moves the process to step S4.

(Step S3)
If it is determined in step S2 that the height position of the counterweight W is greater than or equal to the predetermined height, in step S3, the CPU stops the engine E and ends the engine stop control process.

(Step S4)
If it is not determined in step S2 that the height position of the counterweight W is greater than or equal to the predetermined height, in step S4, the CPU performs an operation of moving the counterweight W upward and ends the engine stop control process. To do.

  Further, when starting the engine E stopped by the idling stop function, the controller 60 determines whether or not the hydraulic oil stored in the elevating cylinder 41 can be used when the engine E is started, and according to the determination result. An engine start control process for starting the engine E is performed. The operation of the CPU of the controller 60 at this time will be described using the flowchart of FIG.

(Step S11)
In step S11, the CPU determines whether or not the engine start switch 62 has been operated. If it is determined that the engine start switch 62 has been operated, the process proceeds to step S12. If it is not determined that the engine start switch 62 has been operated, the engine start control process ends.

(Step S12)
If it is determined in step S11 that the engine start switch 62 has been operated, in step S12, the CPU determines whether the height position of the counterweight W is greater than or equal to a predetermined height based on the detection signal from the height detection sensor 61. Determine whether or not. When it is determined that the height position of the counterweight W is equal to or greater than the predetermined height, the process proceeds to step S13, and when it is not determined that the height position of the counterweight W is equal to or greater than the predetermined height. Moves the process to step S15.

(Step S13)
If it is determined in step S12 that the height position of the counterweight W is equal to or greater than the predetermined height, in step S13, the CPU sets the flow path of the flow path switching valve 48 to the pump motor drive flow path 47 side, The process moves to step S14.

(Step S14)
In step S13, after setting the flow path of the flow path switching valve 48 to the pump motor drive flow path 47 side, in step S14, the CPU sets the clutch 49 in a state where the engine E and the hydraulic pump motor 43 are connected, and in step S17. Move processing to.

(Step S15)
If it is not determined in step S12 that the height position of the counterweight W is greater than or equal to the predetermined height, in step S15, the CPU sets the flow path of the flow path switching valve 48 to the hydraulic oil tank 44 side, The process moves to step S16.

(Step S16)
In step S15, after setting the flow path of the flow path switching valve 48 to the hydraulic oil tank 44 side, in step S16, the CPU sets the clutch 49 in a state in which the connection between the engine E and the hydraulic pump motor 43 is released, and step S17. Move processing to.

(Step S17)
After connecting the engine E and the hydraulic pump motor 43 in step S14, or after releasing the connection between the engine E and the hydraulic pump motor 43 in step S16, in step S17, the CPU drives the starter motor 50 to drive the engine. The start control process is terminated.

  As described above, according to the working machine of the present embodiment, when the counterweight W is moved downward, the hydraulic pump motor 43 is moved by the hydraulic oil flowing out of the lifting cylinder 41 due to the weight of the counterweight W acting. Driven.

  As a result, the hydraulic pump motor 43 can be driven without the need for an accumulator, so the hydraulic oil in the hydraulic oil circuit 42 can be used effectively without increasing the size of the apparatus. .

  Further, the rotational force of the hydraulic pump motor 43 driven by the hydraulic oil flowing out from the elevating cylinder 41 is transmitted to the engine E as the rotational force for starting the engine E.

  As a result, it is possible to reduce the load on the starter motor 50 and the battery that supplies the electric power for driving the starter motor 50 when the engine E is started, so that the life of the starter motor 50 and the battery can be extended. It becomes.

  Further, the counterweight W is moved upward by the elevating cylinder 41 before the engine E is stopped by the idling stop function.

  Thereby, when starting the engine E stopped by the idling stop function, the rotational force of the hydraulic pump motor 43 driven by the hydraulic oil flowing out from the elevating cylinder 41 can be reliably used for starting the engine E. Therefore, the load on the starter motor 50 can be reliably reduced.

  Further, when starting the engine E stopped by the idling stop function, if the mounting height of the counterweight W detected by the height detection sensor 61 is less than a predetermined height, the rotational force of the hydraulic pump motor 43 is reduced. The transmission to the engine E is regulated.

  As a result, the height position of the counterweight W can be prevented from lowering and coming into contact with the lower traveling body 10, so that the structural members of the mobile crane 1 can be prevented from being damaged.

  FIG. 8 shows another embodiment of the present invention. In addition, the same code | symbol is attached | subjected and shown to the component similar to the said embodiment.

  The hydraulic oil circuit 42 of the counterweight lifting / lowering device 40 of the present embodiment is connected to the hydraulic oil outflow side of the hydraulic pump motor 43 in parallel with the lifting / lowering cylinder 41 and turns the upper swing body 20 with respect to the lower traveling body 10. A turning motor 31 is connected as another actuator for this purpose. The rotation direction of the turning motor 31 is switched by the direction switching valve 51.

  The hydraulic oil circuit 42 is actuated by the weight of the counterweight W to actuate the hydraulic oil flowing out from the reduced-side hydraulic oil inlet 41d of the cylinder tube 41a to the P port of the direction switching valve 51. A drive channel 52 is provided.

  The actuator drive flow path 52 connects the hydraulic oil flow path between the check valve 46 and the reduction-side hydraulic oil inlet 41d and the hydraulic oil flow path connected to the P port of the direction switching valve 51. It is. The end of the actuator drive channel 52 on the direction switching valve 51 side is a flow for switching the hydraulic oil channel connected to the P port of the direction switch valve 51 to the hydraulic pump motor 43 side or the actuator drive channel 52 side. It is connected via a path switching valve 53. In addition, a check valve 54 for restricting the flow of hydraulic oil from the turning motor 31 toward the hydraulic pump motor 43 is connected to the hydraulic oil flow path positioned on the hydraulic pump motor 43 side with respect to the flow path switching valve 53. Has been.

  In the mobile crane 1 configured as described above, the turning motor 31 can be driven by the hydraulic oil discharged from the hydraulic pump motor 43 while the engine E is being driven. In addition, when the engine E is stopped, the mobile crane 1 sets the flow path of the flow path switching valve 53 to the actuator drive flow path 52 side, so that the turning motor 31 is moved by the hydraulic oil flowing out from the lifting cylinder 41. To drive.

  As described above, according to the working machine of the present embodiment, when the counterweight W is moved downward, the swivel motor 31 is driven by the hydraulic oil flowing out from the lifting cylinder 41 due to the weight of the counterweight W acting. I am letting.

  As a result, the swing motor 31 can be driven without requiring an accumulator, so that the hydraulic oil in the hydraulic oil circuit 42 can be used effectively without increasing the size of the apparatus.

  In the above embodiment, the mobile crane 1 is shown as the work machine. However, the present invention is not limited to the mobile crane as long as it is a work machine having a device for raising and lowering the counterweight.

  In the above embodiment, the hydraulic pump motor 43 and the turning motor 31 are driven by the hydraulic oil flowing out from the elevating cylinder 41. For example, an actuator for driving the telescopic boom or winch of the crane device 22 is shown. May be driven.

  Further, in the above-described embodiment, the rotational force of the input / output shaft of the hydraulic pump motor 43 is added to the output shaft of the engine E together with the driving force of the starter motor 50 to start the engine E. However, it is not limited to this. For example, the engine E may be started without driving the starter motor 50 by adding only the rotational force of the input / output shaft of the hydraulic pump motor 43 to the output shaft of the engine E.

  DESCRIPTION OF SYMBOLS 1 ... Mobile crane, 31 ... Swing motor, 40 ... Counterweight raising / lowering device, 41 ... Lifting cylinder, 43 ... Hydraulic pump motor, 47 ... Pump motor drive flow path, 48 ... Flow path switching valve, 52 ... Actuator drive flow path 53 ... Flow path switching valve, 60 ... Controller, 61 ... Height detection sensor, E ... Engine, W ... Counterweight.

Claims (4)

Counterweight,
A lifting actuator that moves the counterweight in the vertical direction;
A hydraulic fluid circuit connected to the lift actuator;
Actuator driving means for driving other actuators connected to the hydraulic fluid circuit by hydraulic fluid flowing out from the lifting actuator when the weight of the counterweight acts when the counterweight is moved downward by the lifting actuator. A working machine characterized by having. A hydraulic pump motor having the functions of a hydraulic pump and a hydraulic motor;
An engine coupled to the hydraulic pump motor and driving the hydraulic pump motor;
The rotational force transmission means which transmits the rotational force of the hydraulic pump motor as another actuator driven by the actuator drive means to the engine as the rotational force for starting the engine is provided. Work machine. Engine stop means for stopping the engine when a predetermined condition is satisfied;
The work machine according to claim 2, further comprising: a counterweight moving unit that moves the counterweight upward by an elevating actuator before the engine is stopped by the engine stop unit. A height detecting means for detecting the mounting height of the counterweight;
When the engine stopped by the engine stop means is started, if the counterweight attached height detected by the height detection means is less than a predetermined height, transmission of the rotational force to the engine by the rotational force transmission means is restricted. The working machine according to claim 2, further comprising: a rotational force transmission restricting unit that performs the operation.

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