WO2003027505A1

WO2003027505A1 - Hydraulic circuit of working machine

Info

Publication number: WO2003027505A1
Application number: PCT/JP2002/009809
Authority: WO
Inventors: Masami Kondo
Original assignee: Yanmar Co.,Ltd.
Priority date: 2001-09-25
Filing date: 2002-09-24
Publication date: 2003-04-03
Also published as: JP2003097505A

Abstract

A hydraulic circuit of a working machine capable of preventing all actuators from being functionally stopped when a pilot hydraulic pressure supply source fails to assure the least safety, wherein an unloading oil passage selector valve (35) is installed between an unloading hydraulic passage leading to an oil tank and oil passages (36) and (40) for supplying oil to the control valves of the hydraulic actuators, and a first hydraulic pump (31), and a directional control valve (50) is installed in the discharge oil passage of a second hydraulic pump (32) in the working machine formed so that the hydraulic pressure supply controls of the plurality of hydraulic actuators are performed by the corresponding control valves and the selecting operations of the control valves are performed by using pilot-operated means and the other operating means such as manual operating means, the directional control valve (50) comprises two ports having oil feed directions different from each other and the ports are made switchable between a direction for supplying pressure oil from the second hydraulic pump (32) and a direction for supplying pressure oil to the oil tank by a safety lever (50a).

Description

T / JP02 / 09809 Description Hydraulic circuit of work machine

The present invention relates to a technology of a hydraulic circuit of a hydraulic working machine such as an excavation turning vehicle. More specifically, the present invention relates to a lock mechanism technology for preventing an erroneous operation of an operation lever such as turning. Background art

An operating lever is provided in the driver's seat to operate the hydraulic actuators in order to perform the turning operation of the pump, arm, bucket, etc., which are the working machines of the excavation and turning work vehicle, and to turn and run. ing. The operation lever is configured to directly operate the spool of the switching valve, or to switch the switching valve by operating the pilot valve.

Conventionally, in a circuit for supplying pressure oil to the switching valve, as shown in FIG. 5, two output oil passages 1 1 3 1 1 4 of a pump 1 1 1 serving as a pressure oil supply source are unloaded. The oil passage switching valve 1 10 is communicated, and the unload oil passage switching valve 1 10 is connected to the center oil passage 1 15 * 1 16 and the unload oil passage 1 1 2 leading to the oil tank. ing. Each switching valve 1 17 ···· is connected to the center oil passage 1 1 · 5 · 1 1 · 6 so as to drive each hydraulic actuator.

On the other hand, in a circuit for supplying pilot pressure oil to the pilot valve, an oil passage 102 is connected to the discharge side of a pump 101 serving as a pilot pressure oil supply source, and the other end of the oil passage 102 is Connect to the safety pulp 103 pump port. The tank port of the safety valve 103 is connected to the oil tank, and when the safety valve 103 locks, the pressure oil from the pump 101 flows into the oil tank. Then, one end of a pilot oil passage 104 is connected to the output port of the safety valve 103.

The other end of the pipe oil passage 104 is connected to one end of a pilot oil passage 105 and one end of a branch pilot oil passage 106 from a branch point. In addition, the pilot oil passage 105 The other end is connected to a first pilot oil passage 107 and a second pilot oil passage 1 ′ 08 via a branch point, and the first pilot oil passage 107 and the second pilot oil passage 108 are connected to each other. Each is connected to a pilot switching valve (remote control valve) 109/109. On the other hand, the branch pilot oil passage 106 is connected to the pilot port 110 a of the operation section of the unload oil passage switching valve 110.

The pilot oil passages 90 to 97 from the pilot switching valve 109 * 109 are connected to pilot ports 90 to 97 of the same reference numerals of the respective switching valves 117,.

A technique for controlling the driving of each hydraulic factor by switching the safety valve 103 in such a circuit is known from Japanese Patent No. 3153118. In the hydraulic circuit described above, when the pump 101, which is the pilot pressure oil supply source, fails, unloading occurs because pressure oil is not supplied to the pilot operation section 110a of the unload oil path switching valve 110. The oil passage switching valve 1 10 was not switched and remained open.

Therefore, the pressure oil supplied to the unloading oil passage switching valve 110 from the pump 111, which is a pressure oil supply source, is sent from the unloading oil passage 112 to the oil tank. 1 1 7 ························································· 1 1 7 ························································

However, in the case of a work machine that operates in a poor working environment, depending on the factory, if the function stops, the work machine itself and the operator may be seriously damaged. In other words, there is a hydraulic work station where the prevention of the function stop is given priority over the prevention of erroneous operation, and there is a problem in that all the hydraulic work stations stop functioning.

For example, in the case of backhoes, turning accidents are the most common, and erroneous turning operations must be completely prevented. On the other hand, it is imperative to always have a system that enables escape in the event of a secondary disaster, such as fire restoration work.However, running, the largest escape function, is added to prevent accidental operation. If the function is stopped due to the failure of the installed equipment, there will be a safety problem. Disclosure of the invention

The present invention is configured such that the hydraulic pressure supply control for a plurality of hydraulic factories is performed by each corresponding control valve, and the switching operation of each control valve is performed by both operating means of pilot operating means and other operating means. An unloading oil passage leading to an oil tank, an oil passage to be supplied to a control valve of each of the hydraulic actuators, and an unopening oil passage switching valve are provided between a hydraulic supply source. The unopened oil passage switching valve is loaded as a pilot operated type when the pilot hydraulic pressure is not applied, a discharge oil passage from a pilot hydraulic supply source, an oil tank, and the pilot operation. A direction switching valve interlocking with a safety lever is provided between a supply oil passage to the means and a pilot oil passage connected to an operation portion of the unsealed oil passage switching valve; Directional valve A position for supplying pressure oil to the pilot operating means and opening the unloading oil passage switching valve, and a position for draining the pressure oil of the pilot operating means and unloading the unopening oil passage switching valve When the safety lever is operated in the non-working state, all the actuators are disabled, and the safety lever is released to the working state to release all the actuators. The evening can be activated. If the pilot pressure oil supply source does not operate due to a failure or the like, the unloading oil passage switching valve is switched to the opening side, and pressure oil is supplied to the control valve. The function operated by the pilot operating means stops functioning, but pressure oil is supplied to the control valve operated by other operating means to operate the actuator, and the operation of the actuator is started. It is possible to secure the minimum safety.

Further, in the present invention, the turning motor is included in the hydraulic actuator controlled by the above-mentioned pilot operating means, and the traveling motor is included in the hydraulic actuator controlled by the other operating means. With this configuration, if the pilot pressure oil supply source of a hydraulic work vehicle such as a backhoe fails, the swing motor is not operated, preventing erroneous operation and ensuring safety.The traveling motor can be operated, ensuring safety. For this reason, the driver can drive and drive to run and escape to maintain an escape system at all times.

Further, the present invention provides a pressure sensor in a discharge oil passage of the above-described pilot pressure oil supply source. The pressure sensor is connected to an alarm and an alarm is issued when the pressure becomes lower than the set pressure. Thus, erroneous operation by other operation means can be prevented. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an overall side view of an excavation turning work vehicle having a hydraulic circuit according to the present invention. FIG. 2 is a hydraulic circuit diagram when the directional control valve is closed.

FIG. 3 is a hydraulic circuit diagram when the direction switching valve is unlocked.

FIG. 4 is a hydraulic circuit diagram when a pressure switch and an alarm are provided.

FIG. 5 is a conventional hydraulic circuit diagram. BEST MODE FOR CARRYING OUT THE INVENTION

Next, an embodiment in which the lock mechanism of the present invention is provided as a hydraulic working machine in a digging and turning work vehicle (backhoe) will be described.

As shown in FIG. 1, the excavating and turning work vehicle supports a turning frame 8 so as to be able to turn via a turning table bearing 7 having a vertical axis at the upper center of the crawler-type traveling device 1. A blade 10 is disposed at one of the front and rear ends of the crawler traveling device 1 so as to be vertically rotatable.

Above the revolving frame 8, a bonnet 9 for covering an engine or the like is arranged, and a seat 22 is attached above the bonnet 9. In front of the seat 22, levers for performing a traveling operation, a turning operation, and an operation of the work machine 2 are provided on a front column 19. A step 20 is arranged between the front column 19 and the hood 9.

A work machine 2 is mounted on a front end of the revolving frame 8, and a boom bracket 12 is attached to the work machine 2 so as to be rotatable left and right. The lower end of the boom 6 is attached to the boom bracket 12. It is supported to be able to rotate back and forth. The boom 6 is bent forward at an intermediate portion, and is formed in a substantially “C” shape in a side view. An arm 5 is rotatably supported at the other end of the boom 6, and a bucket 4 as a work attachment is rotatably supported at the end of the arm 5. In addition, a boom cylinder 23 is interposed between the boom bracket 12 and a boom cylinder bracket 25 provided at the front of the middle of the boom 6, and a ram cylinder bottom bracket 2 provided at the back of the middle of the boom 6 is provided. An arm cylinder 29 is interposed between a bucket cylinder bracket 27 provided at the base end of the arm 6 and the arm 5, and a stage 11 is connected to the bucket cylinder bracket 27 and the bucket 4. A bucket cylinder 24 is interposed between them.

Thus, the boom 6 is rotated by the boom cylinder 23, the arm 5 is rotated by the arm cylinder 29, and the bucket 4 is rotated by the bucket cylinder 24. The cylinder 23, the arm cylinder 29, and the bucket cylinder 24 are constituted by hydraulic cylinders as actuators, and each cylinder 23, 29, 24 is an operation provided on the front column 19. By operating the lever, the switching valve disposed below is switched, and the hydraulic pressure is supplied from the hydraulic pump to drive the expansion and contraction.

A swing cylinder 17 is disposed on the side of the swing frame 8, and its base is pivotally supported by the swing frame, and the tip of the cylinder rod of the swing cylinder 17 is connected to the beam bracket 12. The swing cylinder 17 allows the boom bracket 12 to rotate left and right with respect to the turning frame 8, thereby enabling the work machine 2 to rotate left and right.

Further, the turning frame 8 can be turned left and right by 360 degrees by the operation of a turning module 13 provided above the turning table bearing 7. It can be moved up and down by the operation of a blade cylinder 14 interposed between it and the track frame 3 of the traveling device 1. The swing motor 13 is constituted by a hydraulic motor. Further, traveling hydraulic motors are disposed inside the driving sprockets 16-16 disposed on one side of the front and rear of the track frame 3, respectively, so that the traveling device 1 can be driven to travel.

The hydraulic cylinder / hydraulic motor, which constitutes the hydraulic actuator, can be driven by operating an operation lever or pedal provided on the front column 19 and the step 20.

Next, a hydraulic cylinder, which will be used as a hydraulic actuator, and a drilling machine with a hydraulic motor The hydraulic circuit of the rotating work vehicle will be described with reference to FIG.

First, a first hydraulic pump 31 and a second hydraulic pump 32, which are hydraulic pressure sources, are driven in parallel and connected in parallel to an output shaft of an engine E housed in the bonnet 9. An unloading oil passage switching valve 35 is connected to the two output oil passages 3 3 and 3 4 of the first hydraulic pump 31, and a center oil passage 3 is connected to the unloading oil passage switching valve 35. The unloading oil passage 49 leading to the oil tank is connected to 6 · 40 and the center oil passage 36 · 40 is connected to each control valve so that each hydraulic actuator can be driven. The unopened oil passage switching valve 35 is configured as a pilot operated type, and when the pilot oil pressure is applied to the pilot port 35 a of the operation unit, the output oil passages 33, 34 are unloaded. When unloaded by connecting to oil passage 49 and the pilot oil pressure is not supplied, the output oil passages 33, 34 are connected to the center oil passage 36, 40, and the hydraulic oil is supplied to each control valve. It is loaded and each actuary is operational. A relief valve (not shown) for setting the output oil pressure is connected in parallel to the first center oil passage 36 on the output side of the output oil passage 33, and the vehicle travels on one of the left and right sides (the right side in this embodiment). To the hydraulic motor 45, a directional switch valve for traveling motor 37 that switches oil supply to the hydraulic motor 45, to the boom cylinder 23, a directional valve for boom 38 that switches oil supply to the cylinder 23 (Fig. 1), and to the swing hydraulic motor 13. And a turning direction switching valve 39 for switching the oil supply of the fuel tank is connected in tandem. A pilot port 38 a · 38-39 a-39 b is formed in the operation part of the boom direction switching valve 38 and the turning direction switching valve 39, and by operating the operation lever 43. A hydraulic valve (boom cylinder 23, swing hydraulic motor 13) can be operated by switching a control valve by switching a pilot valve described later.

Further, a second center oil passage 40 can be connected to the output oil passage 34, and a relief valve (not shown) for setting an output oil pressure is connected in parallel to the second center oil passage 40. Directional switching valve 37 L for traveling motor for switching oil supply to the traveling hydraulic motor 46 on the side (left side in this embodiment) and directional switching valve for swing for switching oil supply to swing cylinder 17 (Fig. 1) The directional control valve 42 for switching the oil supply to the arm cylinder 29 (Fig. 1) is connected in tandem with 41. The pilot port is connected to the operating parts of the swing direction switching valve 41 and the arm direction switching valve 42. G 41 a '41 b' 42 a '42 b is formed. By operating the operation lever 44, the pilot valve, which will be described later, is switched to switch the control valve, and the hydraulic actuator (swing cylinder 17, Arm cylinder 29) can be operated.

However, in this embodiment, the number of the switching valves 37 R, 38, 39, 37 L, 41, and 42 as control valves is six, but the number and the number of hydraulic actuators to be operated are not limited. Other switching valves can be added.

Traveling the travel motor directional control valve ₃ 7 R mode Isseki directional switching valve 37 L by operating the operation lever one 37 a · 37 b, and the boom directional control valve 38, the turning direction switching valve 39, The swing direction switching valve 41 and the arm direction switching valve 42 are neutral in that the hydraulic oil from the first and second hydraulic pumps 31 and 32 is not supplied to the hydraulic actuator by operating the operation levers 43 and 44. From position X, it can be switched to pressure oil supply position Y for supplying pressure oil to one input / output port of the corresponding hydraulic actuator or supply position 供給する for supplying pressure oil to the other input / output port .

Of these switching valves, the swing, arm, boom, and swing switching valves 41, 42, 38, and 39, which are switched by operating levers 43 and 44, are pilot operated, and each pilot valve described later From 56, 57, 58, 59, each pilot port 38 a-38 b * 39 a-39 b-41 a * 41 b-42 a 'formed on each switching valve 38, 39, 41, 42 By supplying the pilot pressurized oil to 42b, it is configured to switch from the neutral position X to the pressurized oil supply position Y or Z.

Also, the left and right traveling motor direction switching valves 37R and 37L can be switched by manual operation, and are distinguished from the pilot-type operation means. This operation means is not limited to manual operation, and is electrically operated. (Electromagnetic valve type). The left and right traveling motor direction switching valves 37R and 37L are connected to the respective switching valves via links and the like, and are operated from the operation levers 37a and 37b to operate from the neutral position X to the hydraulic oil supply position Y or It is configured as a manual type that switches to Z. Next, the pilot hydraulic pressure supply circuit of the present invention will be described with reference to FIG. The second hydraulic pump (hydraulic supply source) 32 is configured so that part of the pressure oil supplied from it is used as pilot oil pressure. The pressure oil discharged from the second hydraulic pump 32 is supplied to a direction switching valve (safety valve) 50 via a pilot hydraulic discharge oil passage 51.

The direction switching valve 50 is a 4-port 2-position switching valve, and is a safety valve capable of locking and unlocking the operation of the hydraulic actuator. The directional control valve 50 is provided with a safety lever 50a, and the safety lever 50a can switch between locking and unlocking of the hydraulic actuator. However, it is also possible to use a remotely controllable valve such as an electromagnetic valve to link with the safety switch / safety lever.

The pump port of the direction switching valve 50 is connected to the pilot hydraulic discharge oil passage 51, and the tank port is connected to an oil tank.

Also, of the two output ports on the secondary side, the first port is connected to the oil passage 53 to each pilot valve 56, 57, 58, 59, and the second port is connected to the unload oil passage switching valve 35. Connected to pilot oil passage 52 to pilot port 35a.

A branch is formed at the other end of the oil passage 53, and one end of the first oil passage 54 and one end of the second oil passage 55 are connected. The other end of the first oil passage 54 is connected to pump ports of a boom pilot valve 56 and a turning pilot valve 57, and the other end of the second oil passage 55 is connected to a swing pilot valve 58 and an arm pilot. The pump is connected to the pump port of the valve 59, so that the hydraulic oil from the second hydraulic pump 32 can be supplied to each of the pilot valves 56, 57, 58, 59.

From the pilot valves 56, 57, 58, and 59 for the boom, swing, swing, and arm, the pilot hydraulic pressure is changed from the direction switching valve 38, 39, 41, for the boom, swing, swing, and arm. 42 pilot ports 38a-38b-39a-39b-41a-41b-42a-42b.

The pilot ports 38a, 38b-39a-39b-41a-41b-42a-42b of the directional valves 38, 39, 41, 42 have 90 These are designated by pilot valves 56-57-58.

• It means that they are connected to the pilot oil passages 90-97 from 59 with the same sign respectively.

With the above configuration, when the safety lever 50a is locked, as shown in Fig. 2, the pressure oil from the pump port flows to the pilot port oil path 52 to the Oil is fed, and the unopened oil passage switching valve 35 switches to the unload side.

In this state, the pressure oil from the first hydraulic pump 31 is supplied to the unload oil passage switching valve 35 via the output oil passages 33 and 34, and the unload oil passage switching valve 35 is switched to the unload side. Therefore, the pressure oil from the output oil passages 33 and 34 is sent to the tank from the unload oil passage 49 without flowing to the center oil passages 36 and 40. Then, no pressure oil is supplied to each control valve, and even if the operating levers 37 a '37 b' 43 '44 are operated, the hydraulic actuator does not operate.

Therefore, when the safety lever 50a is locked, pressure oil is not supplied to the control valve regardless of the operation of the operation lever 37a'37b43b44, so the hydraulic actuator does not operate, Malfunction of the operation lever can be prevented. When the safety lever 50a is unlocked, as shown in Fig. 3, the hydraulic oil from the pump port is passed through the oil passage 53 to the boom, swing, swing and arm pilot valves 56 and 57. Supplied to 58 and 59, operating lever 43

• By operating 44, each pilot valve 56, 57, 58, 59 is switched, and each control valve 38, 39, 41, 42 Pilot port 38a, 38b, 39a-39b-41a -41 b-42 a-42 b is supplied with pressurized oil. In addition, the unload oil passage switching valve 35 is not supplied with the pipe hydraulic pressure from the direction switching valve 50, and the spool is switched to the load side (unopened one-side release side) by the biasing force of the panel.

On the other hand, the pressure oil from the first hydraulic pump 31 is supplied to the unopened oil passage switching valve 35 via the output oil passages 33 and 34. Since the unloading oil passage switching valve 35 is switched to the opening side, the pressure oil is supplied to the center oil passages 36 and 40. Therefore, hydraulic oil is applied to each pilot valve 56, 57, 58, 59 and control valve. When the control valve is switched by operating each of the operation levers 37 a · 37 b · 43 · 44, the hydraulic actuator can be operated.

Also, if the second hydraulic pump 32, which is the pilot pressure oil supply source, does not operate due to a failure or the like, or if oil leakage or the like occurs, the hydraulic oil from the second hydraulic pump 32 causes the direction switching valve 50 and The oil is not supplied to the oil passage 53, and the pilot valves 56, 57, 58, 59 become inoperable.

Also, since pressure oil is not supplied to the pilot oil passage 52, the oil is not supplied to the pilot port 35a, so that the unloading oil passage switching valve 35 is on the load side and the center oil passage 36, 40 In this case, the hydraulic oil is supplied, and the hydraulic actuator connected to the control valve by another operating means other than the pilot means can be operated.

That is, in this embodiment, since the control valves of the operation means other than the pilot means are the left and right traveling motor direction switching valves 37 L and 37 R, even if the second hydraulic pump 32 is not operated, The hydraulic actuator connected to the left and right traveling motor direction switching valves 37 L-37 R becomes operable, and a system that enables traveling even when the pilot pressure oil supply source fails can be established.

In addition, since the operation of the hydraulic actuator for turning in which the pilot operating means is used becomes inoperable, erroneous operation of turning when the pilot pressure oil supply source fails is ensured.

As shown in FIG. 4, a pressure sensor, for example, a pressure switch 60 is provided in the pilot hydraulic discharge oil passage 51 so as to detect the oil pressure. The pressure switch 60 is provided with a lamp, a buzzer, or the like. When the second hydraulic pump 32, which is a pilot pressure oil supply source, is connected to the alarm 61, the alarm 61 can be activated.

That is, if the pressure in the pilot hydraulic discharge oil passage 51 becomes equal to or less than the set value when the second hydraulic pump 32 fails or an oil leak occurs, the pressure connected to the pilot hydraulic discharge oil passage 51 is reduced. When the switch 60 is turned on, the alarm 61 connected to the pressure switch 60 is activated to issue an alarm, thereby notifying that the second hydraulic pump 32 has failed. The alarm 61 operates only when the engine E is operating, and the alarm 61 issues an alarm by light or sound, etc., and is not limited. No.

With this configuration, when the pilot pressure oil supply source fails, an alarm is issued to notify the operator of the failure and prevent erroneous operation. Industrial applicability

As described above, the hydraulic circuit of the hydraulic working machine according to the present invention is suitable for use in a digging and turning work vehicle such as a backhoe.

Claims

The scope of the claims

1. The hydraulic supply control for multiple hydraulic actuators is configured to be performed by each corresponding control valve, and the switching operation of each control valve is performed by both the pilot operating means and the other operating means. An unloading oil passage switching valve is provided between an unopening oil passage leading to an oil tank, an oil passage for supplying a control valve for each of the hydraulic actuators, and a hydraulic supply source. The unopened oil passage switching valve is set as a pilot operated type to be loaded when the pilot hydraulic pressure is not pressurized, and a discharge oil passage from a pilot hydraulic supply source, an oil tank, and a supply oil passage to the pilot operation means. A directional switching valve interlocking with a safety lever is provided between the pilot oil passage connected to the operating section of the unloading oil passage switching valve, and a directional switching valve; Switch between the position where the hydraulic oil is supplied to the port operating means and the unload oil path switching valve is loaded, and the position where the pressure oil of the pilot operating means is drained and the unload oil path switching valve is unloaded A hydraulic circuit for a working machine, characterized by being configured as possible.

2. The hydraulic motor controlled by the pilot operating means includes a turning motor, and the hydraulic motor controlled by another operating means includes a traveling motor. The hydraulic circuit of a working machine according to claim 1, wherein

3. A pressure sensor is provided in a discharge oil passage of the pilot pressure oil supply source, the pressure sensor is connected to an alarm device, and an alarm is issued when the pressure falls below a set pressure. Hydraulic circuit of the work machine according to item 1.