JPH0228722B2 - YUATSUSHIKIKENSETSUSHARYONOKUDOKAIRO - Google Patents

YUATSUSHIKIKENSETSUSHARYONOKUDOKAIRO

Info

Publication number
JPH0228722B2
JPH0228722B2 JP58116928A JP11692883A JPH0228722B2 JP H0228722 B2 JPH0228722 B2 JP H0228722B2 JP 58116928 A JP58116928 A JP 58116928A JP 11692883 A JP11692883 A JP 11692883A JP H0228722 B2 JPH0228722 B2 JP H0228722B2
Authority
JP
Japan
Prior art keywords
pressure
drive circuit
switch
rated
relief valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
JP58116928A
Other languages
Japanese (ja)
Other versions
JPS5917003A (en
Inventor
Akinori Ikeda
Fuyuki Nagai
Takashi Okuno
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Construction Machinery Co Ltd
Original Assignee
Hitachi Construction Machinery Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Construction Machinery Co Ltd filed Critical Hitachi Construction Machinery Co Ltd
Priority to JP58116928A priority Critical patent/JPH0228722B2/en
Publication of JPS5917003A publication Critical patent/JPS5917003A/en
Publication of JPH0228722B2 publication Critical patent/JPH0228722B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20538—Type of pump constant capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/25—Pressure control functions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/321—Directional control characterised by the type of actuation mechanically
    • F15B2211/324—Directional control characterised by the type of actuation mechanically manually, e.g. by using a lever or pedal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40576—Assemblies of multiple valves
    • F15B2211/40584—Assemblies of multiple valves the flow control means arranged in parallel with a check valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/41—Flow control characterised by the positions of the valve element
    • F15B2211/413—Flow control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow control characterised by the type of actuation actuated by fluid pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/47—Flow control in one direction only
    • F15B2211/473—Flow control in one direction only without restriction in the reverse direction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve
    • F15B2211/5155—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve being connected to multiple output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6653—Pressure control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/85—Control during special operating conditions

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Operation Control Of Excavators (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Fluid-Pressure Circuits (AREA)

Description

【発明の詳細な説明】 本発明は、油圧式クローラクレーン、油圧シヨ
ベル等の油圧式建設車輛の油圧駆動回路に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic drive circuit for a hydraulic construction vehicle such as a hydraulic crawler crane or a hydraulic excavator.

前記の如き油圧式建設車輛においては、あらゆ
る作業を考慮して駆動回路の定格圧力が設定され
ているが、例えば埋設された杭を引抜く場合、ド
ラグラインのバケツト引寄せ時に大石等がバケツ
トに引掛つた場合、あるいは泥ねい地からの脱出
のための走行駆動時などに定格出力以上の力を必
要とする場合がある。このような定格出力以上の
出力が要求された場合、油圧式建設車輛では、エ
ンジンのフライホイールの慣性力等により定格時
の130〜150％出力を一時的に（数秒間）出すこと
ができるが、油圧式建設車輛ではその最大出力が
油圧駆動回路のメインリリーフ弁のリリーフ圧力
によつて決定されているため、前記の如き定格出
力以上の出力が要求された場合にこれに対処する
ことができず、機械式に比べると瞬発力がないと
云われている。 In hydraulic construction vehicles such as those mentioned above, the rated pressure of the drive circuit is set in consideration of all types of work. In some cases, a force exceeding the rated output may be required when the vehicle is caught, or when driving to escape from muddy ground. When an output higher than the rated output is required, hydraulic construction vehicles can temporarily (for a few seconds) output 130 to 150% of the rated output due to the inertia of the engine's flywheel. Since the maximum output of a hydraulic construction vehicle is determined by the relief pressure of the main relief valve of the hydraulic drive circuit, it is not possible to cope with the above-mentioned requests for output exceeding the rated output. First, it is said that it does not have instantaneous force compared to mechanical types.

油圧式建設車輛の出力を大きくするには、油圧
モータと巻上ドラム等の減速比を大きくしたり回
路中のメインリリーフ弁のリリーフ圧力を高くす
ることにより可能である。しかし、ポンプ容量を
そのままにして減速比を大きくすると作業速度が
おそくなり、ポンプ容量、エンジン容量を増大さ
せて減速比を大きくすれば原価アツプや騒音乃至
燃費の増大を招く。また、メインリリーフ弁のリ
リーフ圧を高くすると、油圧ポンプ、油圧モー
タ、その他すべての油圧機器を高圧に耐えるもの
にする必要が生じ、原価アツプになり、逆に油圧
機器をそのままにしてメインリリーフ弁のリリー
フ圧のみを高めると寿命および耐久性に欠ける難
点がある。 The output of a hydraulic construction vehicle can be increased by increasing the reduction ratio of the hydraulic motor, hoisting drum, etc., or by increasing the relief pressure of the main relief valve in the circuit. However, if the reduction ratio is increased while the pump capacity remains the same, the working speed will be slow, and if the reduction ratio is increased by increasing the pump capacity and engine capacity, this will lead to increased costs, noise, and fuel consumption. In addition, if the relief pressure of the main relief valve is increased, the hydraulic pump, hydraulic motor, and all other hydraulic equipment must be made to withstand high pressure, which increases the cost. If only the relief pressure is increased, the service life and durability will be shortened.

本発明は、前述の如き従来の油圧式建設車輛の
問題点に鑑み、定格出力以上の出力が要求される
場合には、定格出力の130〜150％の如き機械式な
みのねばりのある出力を得ることができ、しか
も、油圧ポンプ、油圧モータその他の油圧機器は
従来の油圧機器と同等のものであつても何等差支
えなく、かつ、エンジン容量は従来のままであつ
てもエンストするおそれがない油圧式建設車輛の
駆動回路を提供せんとするものである。 In view of the problems of conventional hydraulic construction vehicles as described above, the present invention provides a flexible output similar to that of a mechanical type, such as 130 to 150% of the rated output, when an output higher than the rated output is required. Moreover, there is no problem even if the hydraulic pump, hydraulic motor, and other hydraulic equipment are equivalent to conventional hydraulic equipment, and there is no risk of engine stalling even if the engine capacity remains the same. The present invention aims to provide a drive circuit for a hydraulic construction vehicle.

本発明は、前記の如き目的を達成せんがため、
メインリリーフ弁のリリーフ圧を駆動回路の定格
圧力より高い圧力に設定し、このメインリリーフ
弁のベントポートに駆動回路の定格圧力と等しい
リリーフ圧に設定したベントリリーフ弁を接続
し、該ベントリリーフ弁のタンクポートを電磁切
換弁を介してタンクに接続し、他方、駆動回路内
の圧力が定格圧力に達するとこれを検出する圧力
スイツチを具備し、その圧力スイツチを前記電磁
切換弁の回路に挿入し、圧力スイツチが定格圧力
に達したことを検出していないときは前記電磁切
換弁をベントリリーフ弁のタンクポートがタンク
と遮断された位置とし、圧力スイツチが定格圧力
に達したことを検出するとそれより一定の短時間
遅れてベントリリーフ弁のタンクポートがタンク
と連通する位置に電磁切換弁を切換えるように構
成したことを特徴とする。 In order to achieve the above objects, the present invention has the following features:
The relief pressure of the main relief valve is set to a pressure higher than the rated pressure of the drive circuit, and the vent relief valve whose relief pressure is set to be equal to the rated pressure of the drive circuit is connected to the vent port of this main relief valve. The tank port is connected to the tank via an electromagnetic switching valve, and the pressure switch is equipped with a pressure switch that detects when the pressure in the drive circuit reaches the rated pressure, and the pressure switch is inserted into the circuit of the electromagnetic switching valve. However, when the pressure switch does not detect that the rated pressure has been reached, the solenoid switching valve is set to a position where the tank port of the vent relief valve is isolated from the tank, and when the pressure switch detects that the rated pressure has been reached, The present invention is characterized in that the electromagnetic switching valve is configured to switch to a position where the tank port of the vent relief valve communicates with the tank after a certain short time delay.

本発明の駆動回路は、前記の如き構成よりなる
ので、駆動回路の圧力が定格圧力に達したことを
圧力スイツチが検出してから電磁切換弁が切換わ
るまでの一定の短時間の間はベントリリーフ弁の
タンクポートがタンクと遮断されたままで駆動回
路の圧力はメインリリーフ弁に設定された圧力ま
で上昇し、その間、フライホイールの慣性力によ
りエンジントルクが一時的に定格トルクより増大
して瞬発力を得ることができ、その後はベントリ
リーフ弁に設定された定格圧力に復帰するので、
油圧機器の寿命および信頼性をそこなうおそれが
なく、かつ、エンストのおそれもない。 Since the drive circuit of the present invention has the above-described configuration, the vent is not activated for a certain short period of time after the pressure switch detects that the pressure in the drive circuit has reached the rated pressure until the solenoid switching valve switches. While the tank port of the relief valve remains isolated from the tank, the pressure in the drive circuit rises to the pressure set in the main relief valve, and during this period, the engine torque temporarily increases above the rated torque due to the inertia of the flywheel. After that, the pressure will return to the rated pressure set on the vent relief valve.
There is no risk of damaging the lifespan and reliability of hydraulic equipment, and there is no risk of engine stalling.

次に、従来の油圧式建設車輛の例を第１図に示
す巻上油圧回路について説明し、これに引続いて
本発明駆動回路の実施例を第２図以下について説
明する。 Next, as an example of a conventional hydraulic construction vehicle, a hoisting hydraulic circuit shown in FIG. 1 will be described, and then an embodiment of the drive circuit of the present invention will be described with reference to FIGS.

第１図において、１は油圧ポンプ、３は切換
弁、５はカンバラ弁、７は油圧モータ、８は減速
機、９は巻上ドラム、１２はシヨツクリリーフ
弁、１３はメインリリーフ弁を示し、油圧ポンプ
１から吐出された油は、切換弁３の操作レバー３
ａを操作して切換弁３をＡ位置にすることにより
管路２，４、カンバラ弁５、管路６を経て油圧モ
ータ７に達し、油圧モータ７を駆動する。油圧モ
ータ７から出た油は、管路１０、切換弁３、管路
１１を経てタンクへ戻る。カンバラ弁５は、巻下
げ時の吊荷の落下を防止し、シヨツクリリーフ弁
１２は管路６に発生する高圧力をカツトする。油
圧モータ７には減速機８を介して巻上ドラム９が
接続され、メインリリーフ弁１３によつて設定さ
れたリリーフ圧によつて発生するモータ駆動トル
クに応じて巻上力で巻上ドラムを駆動するが、こ
の巻上力はメインリリーフ弁１３に設定されたリ
リーフ圧以上のものを得ることはできない。 In FIG. 1, 1 is a hydraulic pump, 3 is a switching valve, 5 is a Kambara valve, 7 is a hydraulic motor, 8 is a reduction gear, 9 is a hoisting drum, 12 is a shot relief valve, 13 is a main relief valve, The oil discharged from the hydraulic pump 1 is transferred to the operating lever 3 of the switching valve 3.
By operating the switch a and setting the switching valve 3 to the A position, it reaches the hydraulic motor 7 via the pipes 2 and 4, the Kanbara valve 5, and the pipe 6, and drives the hydraulic motor 7. Oil discharged from the hydraulic motor 7 returns to the tank via a pipe line 10, a switching valve 3, and a pipe line 11. The Kambara valve 5 prevents the suspended load from falling during hoisting, and the shot relief valve 12 cuts off the high pressure generated in the pipe line 6. A hoisting drum 9 is connected to the hydraulic motor 7 via a reducer 8, and the hoisting drum is driven by a hoisting force in accordance with the motor drive torque generated by the relief pressure set by the main relief valve 13. However, this hoisting force cannot exceed the relief pressure set in the main relief valve 13.

第２図は前記第１図に示す駆動回路に本発明を
適用した一例を示す回路図である。 FIG. 2 is a circuit diagram showing an example in which the present invention is applied to the drive circuit shown in FIG. 1.

第２図において、１〜１２は第１図と同一部分
を同一符号で示す。この発明においては、メイン
リリーフ弁１３のリリーフ圧を駆動回路の定格圧
力PAより例えば130％〜150％高いリリーフ圧PC
に設定し、かつそのメインリリーフ弁１３のベン
トポートに、駆動回路の定格圧力と等しいリリー
フ圧PB（＝PA）に設定したベントリリーフ弁１４
を接続し、、さらにそのベントリリーフ弁１４の
タンクポートを電磁切換弁２４を介してタンクに
接続する。この電磁切換弁２４は、常態（Ａ位
置）においてはベントリリーフ弁１４のタンクポ
ートをブロツクし、電磁切換弁２４をＢ位置に切
換えるとベントリリーフ弁１４のタンクポートを
タンクに接続するものである。 In FIG. 2, 1 to 12 indicate the same parts as in FIG. 1 with the same symbols. In this invention, the relief pressure of the main relief valve 13 is set to a relief pressure P C that is, for example, 130% to 150% higher than the rated pressure P A of the drive circuit.
and a vent relief valve 14 set to a relief pressure P B (=P A ) equal to the rated pressure of the drive circuit at the vent port of the main relief valve 13.
and further connect the tank port of the vent relief valve 14 to the tank via the electromagnetic switching valve 24. This electromagnetic switching valve 24 blocks the tank port of the vent relief valve 14 in the normal state (A position), and connects the tank port of the vent relief valve 14 to the tank when the electromagnetic switching valve 24 is switched to the B position. .

前記電磁切換弁２４は、駆動回路の圧力をパイ
ロツト管路２−ａに接続した圧力スイツチ２５に
より検出し、駆動回路の圧力がほゞ定格圧力PA
に達したことを検出すると、ある一定の短時間お
くれてＡ位置からＢ位置に切換えられるように構
成されている。 The electromagnetic switching valve 24 detects the pressure of the drive circuit by a pressure switch 25 connected to the pilot pipe 2-a, and the pressure of the drive circuit is approximately equal to the rated pressure P A
When it is detected that the position has been reached, the position is switched from the A position to the B position after a certain short period of time.

例えば、圧力スイツチ２５は、駆動回路圧力が
定格圧力PAに達するとこれを検知して閉じる圧
力スイツチ、２６は遅延リレー素子２６−ａとリ
レースイツチ２６−ｂとよりなる遅延リレーであ
つて、リレースイツチ２６−ｂが閉じると前記電
磁切換弁２４が付勢されてＡ位置からＢ位置に切
換えられるように電源２７に接続し、かつ前記遅
延リレー２６は、圧力スイツチ２５が閉じた後一
定の短時間例えば数秒後にリレースイツチ２６−
ｂが閉じるものとする。 For example, the pressure switch 25 is a pressure switch that detects and closes when the drive circuit pressure reaches the rated pressure PA , and 26 is a delay relay consisting of a delay relay element 26-a and a relay switch 26-b, When the relay switch 26-b closes, the electromagnetic switching valve 24 is energized and connected to the power source 27 so as to be switched from the A position to the B position, and the delay relay 26 is connected to a constant voltage after the pressure switch 25 is closed. After a short period of time, e.g. a few seconds, the relay switch 26-
b is assumed to be closed.

第２図に示す実施例は、前記の如く構成されて
いるので、駆動回路圧力が定格圧力PAに達する
と、圧力スイツチ２５を閉じ、その後遅延リレー
２６に設定した例えば数秒後にリレースイツチ２
６−ｂを閉じて電磁切換弁２４をＡ位置からＢ位
置に切換える。従つて、遅延リレー２６に設定し
た時間内だけ駆動回路圧力を定格圧力PAより高
い圧力PCまで上昇させ、その後自動的に駆動回
路内圧力をPB＝PAまで復帰させる。すなわち、
この実施例においては、駆動回路内圧力が定格圧
力PAに達したことを圧力スイツチ２５により検
出した時点から電磁切換弁２４をＡ位置からＢ位
置に切換えるまでの時間を遅延リレー２６によつ
て例えば３〜５秒程度の短時間に設定しておけ
ば、その設定時間内だけ駆動回路内圧力をPCま
で上昇させて瞬発力としての増大出力を得ること
ができ、しかもその増大された出力は前記によつ
て設定された短時間だけであつて、その後は自動
的に定格出力に復帰するので、エンストのおそれ
もなく、かつ油圧機器の寿命および信頼性をそこ
なうおそれもない。 The embodiment shown in FIG. 2 is configured as described above, so that when the drive circuit pressure reaches the rated pressure P A , the pressure switch 25 is closed, and then the delay relay 26 is set, for example, after a few seconds, the relay switch 2 is closed.
6-b is closed and the electromagnetic switching valve 24 is switched from the A position to the B position. Therefore, the drive circuit pressure is increased to a pressure P C higher than the rated pressure P A only within the time set in the delay relay 26, and then the drive circuit internal pressure is automatically returned to P B =P A. That is,
In this embodiment, the delay relay 26 controls the time from when the pressure switch 25 detects that the pressure within the drive circuit has reached the rated pressure P A until the electromagnetic switching valve 24 is switched from the A position to the B position. For example, if you set it to a short time of about 3 to 5 seconds, you can increase the pressure in the drive circuit to P C only within that set time and obtain an increased output as an instantaneous force. is only for a short period of time set as described above, after which the output automatically returns to the rated output, so there is no risk of engine stalling and no risk of damaging the lifespan and reliability of the hydraulic equipment.

以上の動作を図示すると第３図のとおりであ
る。いま、駆動回路内の圧力が上昇し、定格圧力
PAに達すると、圧力スイツチ２５は閉じるが、
遅延リレー２６に設定したｔ秒間はリレースイツ
チ２６−ｂが開いているので、電磁切換弁２４は
Ａ位置を保持し、このためｔ秒間は駆動回路内の
圧力はメインリリーフ弁１３のリリーフ圧PCに
よつて決定されてPCまで上昇させ、これにより
増大出力を得ることができ、ｔ秒後電磁切換弁２
４がＡ位置からＢ位置に切換わる、駆動回路内圧
力はベントリリーフ弁１４のリリーフ圧PBにロ
→ハの如く下降し、負荷が変化しなければ圧力
PBが保持される（ハ→ニ）。 The above operation is illustrated in FIG. 3. Now, the pressure inside the drive circuit is rising and reaching the rated pressure.
When P A is reached, the pressure switch 25 closes, but
Since the relay switch 26-b is open for t seconds set in the delay relay 26, the electromagnetic switching valve 24 maintains the A position, and therefore the pressure in the drive circuit is equal to the relief pressure P of the main relief valve 13 for t seconds. C is determined by C and increases to P C , thereby obtaining an increased output, and after t seconds, the solenoid switching valve 2
4 is switched from position A to position B, the pressure inside the drive circuit decreases to the relief pressure P B of the vent relief valve 14 from B to C, and if the load does not change, the pressure
P B is maintained (C → D).

負荷が減少し、駆動回路圧力が低下すると、圧
力スイツチ２５が開き、電磁切換弁２４はＡ位置
に戻、駆動回路のリリーフ圧は再びメインリリー
フ弁１３のリリーフ圧PCに設定され、負荷が大
きくなるとPCまで上昇可能となる。 When the load decreases and the drive circuit pressure decreases, the pressure switch 25 opens, the electromagnetic switching valve 24 returns to the A position, the relief pressure of the drive circuit is again set to the relief pressure P C of the main relief valve 13, and the load decreases. When it gets bigger, it can rise up to P C.

油圧式建設車輛は、定格圧力の上限で駆動され
ることは殆んどないので、実際にはその必配はな
いが、第２図に示す実施例は、駆動回路圧力が定
格圧力PAより僅かに低い圧力になると回路のリ
リーフ圧は再びメインリリーフ弁１３のリリーフ
圧PCに設定されるので、定格圧力PAより高い圧
力PCでの使用頻度が多くなる懸念がある。 Hydraulic construction vehicles are rarely driven at the upper limit of the rated pressure, so in reality it is not necessary, but in the example shown in Figure 2, the drive circuit pressure is lower than the rated pressure P When the pressure becomes slightly lower, the relief pressure of the circuit is again set to the relief pressure P C of the main relief valve 13, so there is a concern that the pressure P C higher than the rated pressure P A will be used more frequently.

第４図はこのような点を改善し、駆動回路圧力
が一旦10Kg／cm2程度の低い圧力PDまで下降しな
い限り電磁切換弁２４がＡ位置に復帰し得ないよ
うにした例を示すものである。 Figure 4 shows an example in which this problem has been improved so that the electromagnetic switching valve 24 cannot return to the A position unless the drive circuit pressure once drops to a low pressure P D of about 10 kg/cm 2 . It is.

第４図において、１〜１４並びに２４は第２図
と同一部分を同一符号で示す。この実施例におい
ては、駆動回路圧力が定格圧力PAになるとこれ
を検知して閉じる第１の圧力スイツチ２８と、10
Kg／cm2程度の低い圧力PD以上になるとこれを検
知して閉じる第２の圧力スイツチ２９とを使用す
る。そして、遅延リレー素子３０−ａと２つのリ
レースイツチ３０−ｂ，３０−ｃとからなる遅延
リレー３０は、駆動回路内圧力が定格圧力PAに
達すると第１の圧力スイツチ２８を閉じて遅延リ
レー素子３０−ａを付勢させ、その後数秒後にリ
レースイツチ３０−ｂ，３０−ｃが共に閉じて電
磁切換弁２４を切換え、かつ該遅延リレー素子３
０−ａの回路を前記低い圧力で閉じる第２の圧力
スイツチ２９と一方のリレースイツチ３０−ｂと
を介して保持し得るように電源２７に接続する。 In FIG. 4, 1 to 14 and 24 denote the same parts as in FIG. 2 with the same reference numerals. In this embodiment, the first pressure switch 28 detects and closes when the drive circuit pressure reaches the rated pressure P A ;
A second pressure switch 29 is used which detects this and closes when the pressure reaches a low pressure P D of about Kg/cm 2 or higher. When the pressure within the drive circuit reaches the rated pressure P A , the delay relay 30 consisting of a delay relay element 30-a and two relay switches 30-b and 30-c closes the first pressure switch 28 and delays the relay. The relay element 30-a is energized, and after a few seconds, the relay switches 30-b and 30-c both close to switch the electromagnetic switching valve 24, and the delay relay element 3
The circuit 0-a is connected to a power source 27 through a second pressure switch 29 that closes the circuit at the low pressure and one relay switch 30-b so as to be maintained.

第４図に示す実施例は、前記の如く構成されて
いるので、駆動回路圧力が上昇し始めて圧力PD
に達すると第２の圧力スイツチ２９は閉じる。し
かし、リレースイツチ３０−ｂは開いているの
で、遅延リレー素子３０−ａにはまだ通電されな
い。駆動回路圧力が更に上昇し、定格圧力PAに
なると第１の圧力スイツチ２８も閉じて遅延リレ
ー素子３０−ａに通電される。このようにして遅
延リレー素子３０−ａに通電された後、ｔ秒間延
遅してリレースイツチ３０−ｂ，３０−ｃが閉じ
るまでの間に駆動回路圧力はメインリリーフ弁１
３に設定された圧力PCに一旦昇圧される。そし
て、遅延リレー素子３０−ａに通電されたｔ秒後
にリレースイツチ３０−ｂ，３０−ｃが閉じると
電磁弁２４はＢ位置に切換り、ベントリリーフ弁
１４が作動して駆動回路圧力はPB（＝PA）に下が
る（第４Ａ図参照）。 Since the embodiment shown in FIG. 4 is constructed as described above, the drive circuit pressure starts to rise and the pressure P D
When the second pressure switch 29 is reached, the second pressure switch 29 closes. However, since relay switch 30-b is open, delay relay element 30-a is not energized yet. When the drive circuit pressure further increases and reaches the rated pressure P A , the first pressure switch 28 is also closed and the delay relay element 30-a is energized. After the delay relay element 30-a is energized in this way, the drive circuit pressure decreases to the main relief valve 1 during a delay of t seconds until the relay switches 30-b and 30-c close.
The pressure is once increased to the pressure P C set at 3. Then, when the relay switches 30-b and 30-c are closed t seconds after the delay relay element 30-a is energized, the solenoid valve 24 is switched to the B position, the vent relief valve 14 is activated, and the drive circuit pressure is reduced to P. B (=P A ) (see Figure 4A).

回路圧力がさらに下がり、圧力PA以下（但し
PD以上）になるると、第１の圧力スイツチ２８
は開いてしまうが、第２の圧力スイツチ２９およ
びリレースイツチ３０−ｂにより遅延リレー素子
３０−ａは通電状態が維持され、駆動回路のリリ
ーフ圧はPB＝定格圧力PAを維持される（第４Ｂ
図参照）。 The circuit pressure further decreases to below pressure P A (however,
P D or higher), the first pressure switch 28
is opened, but the delay relay element 30-a is kept energized by the second pressure switch 29 and relay switch 30-b, and the relief pressure of the drive circuit is maintained at P B = rated pressure P A ( 4th B
(see figure).

第４図に示す実施例は、前記の如く構成されて
いるので、駆動回路内圧力を定格以上の圧力PC
に一旦上昇させた後、電磁切換弁２４をＢ位置に
切換えると、その後駆動回路内圧力が第２の圧力
スイツチ２９により設定した圧力PD以下になら
ない限り、遅延リレー素子３０−ａを第２の圧力
スイツチ２９とリレースイツチ３０−ｂとを介し
て保持し、駆動回路内圧力が前記PD以下まで降
下すると始めて電磁切換弁２４を復帰させるの
で、最高圧力PCの使用頻度もある程度抑制する
ことができる。 The embodiment shown in FIG. 4 is constructed as described above, so that the pressure inside the drive circuit is raised to a pressure higher than the rated pressure P C
When the electromagnetic switching valve 24 is switched to the B position, the delay relay element 30-a is switched to the second position unless the pressure inside the drive circuit becomes lower than the pressure P D set by the second pressure switch 29. The pressure is maintained via the pressure switch 29 and the relay switch 30-b, and the electromagnetic switching valve 24 is reset only when the pressure inside the drive circuit drops below the above-mentioned P D , so the frequency of use of the maximum pressure P C is also suppressed to some extent. be able to.

第４図に示す実施例は、前述の如く、駆動回路
内圧力が一時的に定格圧力以上に昇圧させて瞬発
力としての増大出力が得られるようにし、その後
は回路内圧力が例えば10Kg／cm2の如き低い圧力
PDまで降下しない限り再び定格圧力以上に昇圧
し得ないように構成してあるので、通常の操作で
は定格圧力以上の高負荷が短時間内に断続的にか
かるおそれがない。しかし、連続して大きな出力
が必要な場合、一旦定格圧力以上の高い圧力PC
を発生させた後、操作レバーを操作して駆動回路
圧力をPD以下に低下させれば、短時間内に再度
定格圧力以上の高い圧力PCを発生させることが
できる。 In the embodiment shown in FIG. 4, as described above, the pressure inside the drive circuit is temporarily increased to above the rated pressure to obtain an increased output as an instantaneous force, and then the pressure inside the circuit is increased to 10 kg/cm, for example. 2 low pressure
Since the structure is such that the pressure cannot rise above the rated pressure again unless it drops to P D , there is no risk of a high load above the rated pressure being applied intermittently within a short period of time during normal operation. However, if continuous large output is required, the pressure P C
After generating , if the drive circuit pressure is lowered below P D by operating the operating lever, a high pressure P C higher than the rated pressure can be generated again within a short time.

第５図はこのような点をも考慮し、一旦駆動回
路圧力を定格圧力以上に上昇させると、その後は
駆動回路圧力や操作の如何に拘らず、保安上必要
とするある一定時間内は定格圧力以上の圧力を発
生し得ないようにしたものである。 Figure 5 takes these points into account, and once the drive circuit pressure is raised above the rated pressure, it will remain at the rated pressure for a certain period of time required for safety, regardless of the drive circuit pressure or operation. This prevents the generation of pressure greater than the pressure.

第５図において、１〜１４，２４〜２７は第２
図と同一部分を同一符号で示す。この実施例にお
いては、遅延リレー２６のリレースイツチ２６−
ｂと直列に遅延復旧特性をもつタイマー３１のタ
イマー素子３１−ａを接続し、かつその遅延復旧
タイマースイツチ３１−ｂを電磁切換弁２４の回
路中に接続したものである。 In Fig. 5, 1 to 14, 24 to 27 are the second
The same parts as in the figure are indicated by the same reference numerals. In this embodiment, the relay switch 26- of the delay relay 26 is
A timer element 31-a of a timer 31 having a delay recovery characteristic is connected in series with the delay recovery timer switch 31-b, and the delay recovery timer switch 31-b is connected in the circuit of the electromagnetic switching valve 24.

第５図に示す実施例は、前述の如く構成されて
いるので、駆動回路圧力が定格圧力PAに達して
圧力スイツチ２５を閉じ、遅延リレー２６を動作
させて例えば数秒間だけ駆動回路圧力をPAから
PCに上昇させ、しかる後リレースイツチ２６−
ｂを閉じて電磁切換弁２４を切換え、駆動回路圧
力を定格圧力PAに復帰させると、その後回路圧
力が降下して圧力スイツチ２５が開いても、タイ
マースイツチ３１−ｂはそのタイマーによつて設
定された時間、例えば数十秒間は閉じたままで電
磁切換弁２４の回路を維持するので、駆動回路圧
力の如何に拘らず遅延復旧タイマー３１に設定し
た時間中は再び定格圧力以上に昇圧することを不
可能ならしめる。従つて、遅延復旧タイマーの設
定時間を、保安上必要とする例えば数十秒程度に
設定しておけば、高負荷が油圧機器にかゝる頻度
を制限し、油圧機器の耐久性並びに信頼性を維持
することができる。 The embodiment shown in FIG. 5 is constructed as described above, so that when the drive circuit pressure reaches the rated pressure P A , the pressure switch 25 is closed and the delay relay 26 is activated to reduce the drive circuit pressure for, for example, a few seconds. From P A
Raise it to P C and then turn the relay switch 26-
b is closed and the electromagnetic switching valve 24 is switched to return the drive circuit pressure to the rated pressure P A. Even if the circuit pressure subsequently drops and the pressure switch 25 is opened, the timer switch 31-b is activated by the timer. Since the circuit of the electromagnetic switching valve 24 is maintained by remaining closed for a set time, for example, several tens of seconds, the pressure cannot be increased to above the rated pressure again during the time set in the delay recovery timer 31, regardless of the drive circuit pressure. make it impossible. Therefore, by setting the delay recovery timer to a value of several tens of seconds, which is necessary for safety reasons, it will limit the frequency at which high loads are applied to the hydraulic equipment and improve the durability and reliability of the hydraulic equipment. can be maintained.

以上述べたように、本発明によれば、油圧ポン
プの吐出側に設けたリリーフ弁によつて駆動回路
最高圧力が設定されるように構成した油圧式建設
車輛において、駆動回路の圧力が定格圧力に達し
たことを検出すると、一定の短時間内のみ駆動回
路の圧力を定格圧力よりも上昇させ、しかる後自
動的に定格圧力に復帰せしめるので、油圧ポン
プ、油圧モータ、その他の油圧機器は従来の油圧
機器と同等のものを使用して、機械式と同様にね
ばりのある定格出力以上の瞬発力を得ることがで
き、しかも油圧機器の耐久性や信頼性を維持し、
エンストを起すおそれがない効果がある。 As described above, according to the present invention, in a hydraulic construction vehicle configured such that the maximum pressure of the drive circuit is set by the relief valve provided on the discharge side of the hydraulic pump, the pressure of the drive circuit is set to the rated pressure. When it detects that the pressure has reached the rated pressure, the pressure in the drive circuit is raised above the rated pressure only within a certain short period of time, and then automatically returned to the rated pressure, so hydraulic pumps, hydraulic motors, and other hydraulic equipment By using hydraulic equipment equivalent to the hydraulic equipment of
The effect is that there is no risk of engine stalling.

なお、前記各実施例においては、電磁切換弁の
切換時間を遅延リレーによつて制御した例を示し
たが、遅延リレーに代えてタイマースイツチなど
を使用することもできる。 In each of the above embodiments, an example was shown in which the switching time of the electromagnetic switching valve was controlled by a delay relay, but a timer switch or the like may be used instead of the delay relay.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は従来の油圧式建設車輛の駆動回路の一
例を示す油圧回路図、第２図は本発明の第１の実
施例を示す油圧回路図、第３図は本発明による圧
力状態の説明図、第４図は第２の実施例を示す回
路図、第４Ａ図および第４Ｂ図は第４図に示す実
施例の作用説明図、第５図は第３の実施例を示す
回路図である。 １……油圧ポンプ、２，４，６，１０，１１…
…管路、３……切換弁、５……カンバラ弁、７…
…油圧モータ、８……減速機、９……巻上ドラ
ム、１３……メインリリーフ弁、１４……ベント
リリーフ弁、２４……電磁切換弁、２５，２８，
２９……圧力スイツチ、２６，３０……遅延リレ
ー、２７……電源、３１……遅延復旧タイマ。 Fig. 1 is a hydraulic circuit diagram showing an example of a drive circuit of a conventional hydraulic construction vehicle, Fig. 2 is a hydraulic circuit diagram showing a first embodiment of the present invention, and Fig. 3 is an explanation of the pressure state according to the present invention. 4A and 4B are circuit diagrams showing the second embodiment, FIGS. 4A and 4B are action explanatory diagrams of the embodiment shown in FIG. 4, and FIG. 5 is a circuit diagram showing the third embodiment. be. 1... Hydraulic pump, 2, 4, 6, 10, 11...
...Pipeline, 3...Switching valve, 5...Kanbara valve, 7...
... Hydraulic motor, 8 ... Speed reducer, 9 ... Hoisting drum, 13 ... Main relief valve, 14 ... Vent relief valve, 24 ... Solenoid switching valve, 25, 28,
29...Pressure switch, 26, 30...Delay relay, 27...Power supply, 31...Delay recovery timer.

Claims (1)

【特許請求の範囲】[Claims] １ 油圧ポンプの吐出側に設けたリリーフ弁によ
つて回路最高圧力が決定されるように構成した油
圧式建設車輛において、メインリリーフ弁のリリ
ーフ圧を駆動回路の定格圧力より高い圧力に設定
し、このメインリリーフ弁のベントポートに駆動
回路の定格圧力と等しいリリーフ圧に設定したベ
ントリリーフ弁を接続し、該ベントリリーフ弁の
タンクポートを電磁切換弁を介してタンクに接続
し、他方、駆動回路内の圧力が定格圧力に達する
とこれを検出する圧力スイツチを具備し、その圧
力スイツチを前記電磁切換弁の回路に挿入し、圧
力スイツチが定格圧力に達したことを検出してい
ないときは前記電磁切換弁をベントリリーフ弁の
タンクポートがタンクと遮断された位置とし、圧
力スイツチが定格圧力に達したことを検出すると
それより一定の短時間遅れてベントリリーフ弁の
タンクポートがタンクと連通する位置に電磁切換
弁を切換えるように構成したことを特徴とする油
圧式建設車輛の駆動回路。1. In a hydraulic construction vehicle configured such that the circuit maximum pressure is determined by a relief valve provided on the discharge side of the hydraulic pump, the relief pressure of the main relief valve is set to a pressure higher than the rated pressure of the drive circuit, A vent relief valve set to a relief pressure equal to the rated pressure of the drive circuit is connected to the vent port of this main relief valve, and a tank port of the vent relief valve is connected to the tank via an electromagnetic switching valve. The pressure switch is equipped with a pressure switch that detects when the internal pressure reaches the rated pressure, and the pressure switch is inserted into the circuit of the electromagnetic switching valve, and when the pressure switch does not detect that the rated pressure has been reached, the The solenoid switching valve is placed in a position where the tank port of the vent relief valve is isolated from the tank, and when the pressure switch detects that the rated pressure has been reached, the tank port of the vent relief valve communicates with the tank after a certain short delay. 1. A drive circuit for a hydraulic construction vehicle, characterized in that the drive circuit is configured to switch an electromagnetic switching valve depending on the position.
JP58116928A 1983-06-30 1983-06-30 YUATSUSHIKIKENSETSUSHARYONOKUDOKAIRO Expired - Lifetime JPH0228722B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP58116928A JPH0228722B2 (en) 1983-06-30 1983-06-30 YUATSUSHIKIKENSETSUSHARYONOKUDOKAIRO

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP58116928A JPH0228722B2 (en) 1983-06-30 1983-06-30 YUATSUSHIKIKENSETSUSHARYONOKUDOKAIRO

Related Child Applications (1)

Application Number Title Priority Date Filing Date
JP59051135A Division JPS60109605A (en) 1984-03-19 1984-03-19 Drive circuit for hydraulic construction vehicle

Publications (2)

Publication Number Publication Date
JPS5917003A JPS5917003A (en) 1984-01-28
JPH0228722B2 true JPH0228722B2 (en) 1990-06-26

Family

ID=14699153

Family Applications (1)

Application Number Title Priority Date Filing Date
JP58116928A Expired - Lifetime JPH0228722B2 (en) 1983-06-30 1983-06-30 YUATSUSHIKIKENSETSUSHARYONOKUDOKAIRO

Country Status (1)

Country Link
JP (1) JPH0228722B2 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07116731B2 (en) * 1989-02-23 1995-12-13 油谷重工株式会社 Hydraulic circuit of hydraulic construction and work machinery
JP4727488B2 (en) * 2006-04-03 2011-07-20 日立建機株式会社 Steering control device for work vehicle

Also Published As

Publication number Publication date
JPS5917003A (en) 1984-01-28

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