JP2005344766A - Oil-hydraulic circuit of work vehicle - Google Patents
Oil-hydraulic circuit of work vehicle Download PDFInfo
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- JP2005344766A JP2005344766A JP2004162676A JP2004162676A JP2005344766A JP 2005344766 A JP2005344766 A JP 2005344766A JP 2004162676 A JP2004162676 A JP 2004162676A JP 2004162676 A JP2004162676 A JP 2004162676A JP 2005344766 A JP2005344766 A JP 2005344766A
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- 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
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
- F15B11/162—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for giving priority to particular servomotors or users
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/02—Controlling of coolant flow the coolant being cooling-air
- F01P7/04—Controlling of coolant flow the coolant being cooling-air by varying pump speed, e.g. by changing pump-drive gear ratio
- F01P7/044—Controlling of coolant flow the coolant being cooling-air by varying pump speed, e.g. by changing pump-drive gear ratio using hydraulic drives
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- 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
- F15B2211/20546—Type of pump variable capacity
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- 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
- F15B2211/255—Flow 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
- F15B2211/60—Circuit components or control therefor
- F15B2211/62—Cooling or heating means
-
- 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
- F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
- F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
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- 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
- F15B2211/6652—Control of the pressure source, e.g. control of the swash plate angle
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- 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
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
- F15B2211/7058—Rotary output members
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- 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
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
-
- 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
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/78—Control of multiple output members
- F15B2211/781—Control of multiple output members one or more output members having priority
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
Description
本発明は、作業車両の油圧回路に関する。 The present invention relates to a hydraulic circuit for a work vehicle.
従来から、ラジエータやオイルクーラを冷却するための冷却ファンを油圧モータで駆動するようにした作業車両がある。例えば、特許文献１には、固定容量型の油圧ポンプから吐出した圧油を圧力補償付き流量制御弁で分流して、一部を冷却ファンを駆動する固定容量型の油圧モータに供給すると共に、残りの圧油を作業機へ供給するようにした油圧回路が開示されている。 Conventionally, there is a work vehicle in which a cooling fan for cooling a radiator or an oil cooler is driven by a hydraulic motor. For example, in Patent Document 1, pressure oil discharged from a fixed displacement hydraulic pump is divided by a flow control valve with pressure compensation, and a part thereof is supplied to a fixed displacement hydraulic motor that drives a cooling fan, A hydraulic circuit is disclosed in which the remaining pressure oil is supplied to the work machine.
また、特許文献２に開示された油圧回路では、鉄道車両等の車両に搭載されたエンジン及び油圧装置の冷却ファンを駆動する装置に関して、可変容量型の油圧ポンプからの吐出油を、可変絞り型の絞り機構を有する絞りを経由して、冷却ファン駆動用の固定容量型の油圧モータに供給している。そして、前記絞り前後の差圧すなわちエンジン回転数に応じて前記可変容量型の油圧ポンプの吐出量を制御したり、また冷却水温に応じて前記絞りの開口面積を制御することによって、冷却ファン駆動用の油圧モータの回転数を一定にしている。 Further, in the hydraulic circuit disclosed in Patent Document 2, with respect to a device that drives an engine mounted on a vehicle such as a railway vehicle and a cooling fan of the hydraulic device, oil discharged from a variable displacement hydraulic pump is supplied to a variable throttle type. This is supplied to a fixed displacement hydraulic motor for driving a cooling fan through a diaphragm having a diaphragm mechanism. Then, the cooling fan drive is controlled by controlling the discharge amount of the variable displacement hydraulic pump according to the differential pressure before and after the throttling, that is, the engine speed, and controlling the opening area of the throttling according to the cooling water temperature. The rotational speed of the hydraulic motor is kept constant.
しかしながら、特許文献１に記載の油圧回路によると、次のような問題がある。作業機駆動用と冷却ファン駆動用とを１個の固定容量型油圧ポンプで兼用しているので、固定容量型油圧ポンプから吐出した圧油のうち、冷却ファン駆動用の油圧モータに供給した残りを作業機駆動回路に常時供給している。ところが、この作業機駆動回路においては、作業機を作動させないときでも圧油を作業機駆動用の方向切換弁の中立回路を経由してタンクにドレーンさせており、効率が良いとは言えないという問題がある。 However, the hydraulic circuit described in Patent Document 1 has the following problems. Since the work machine drive and cooling fan drive are shared by a single fixed displacement hydraulic pump, the remaining pressure supplied to the cooling fan drive hydraulic motor out of the pressure oil discharged from the fixed displacement hydraulic pump Is constantly supplied to the work machine drive circuit. However, in this work machine drive circuit, even when the work machine is not operated, the pressure oil is drained to the tank via the neutral circuit for driving the work machine, and it cannot be said that the efficiency is good. There's a problem.
特許文献２に記載の油圧回路では、冷却ファン駆動用として可変容量型の油圧ポンプを用いているが、作業機駆動回路に関しては記載が無い。 In the hydraulic circuit described in Patent Document 2, a variable displacement hydraulic pump is used for driving the cooling fan, but there is no description regarding the work machine drive circuit.
本発明は、上記の問題点に着目してなされたもので、効率を向上して、冷却ファン駆動及び作業機駆動に好適な作業車両の油圧回路を提供することを目的とする。 The present invention has been made paying attention to the above-mentioned problems, and an object thereof is to provide a hydraulic circuit for a work vehicle that improves efficiency and is suitable for driving a cooling fan and a work implement.
上記目的を達成するために、第１発明は、作業車両の油圧回路において、作業機アクチュエータと、冷却ファン駆動用アクチュエータと、前記作業機アクチュエータ及び前記冷却ファン駆動用アクチュエータの両方へ圧油を供給する共通の可変容量型油圧ポンプと、前記作業機アクチュエータへの圧油の流量及び前記冷却ファン駆動用アクチュエータへの圧油の流量を制御する制御装置とを備える構成としている。 To achieve the above object, according to a first aspect of the present invention, in a hydraulic circuit of a work vehicle, pressure oil is supplied to a work machine actuator, a cooling fan drive actuator, and both the work machine actuator and the cooling fan drive actuator. And a control device that controls the flow rate of pressure oil to the working machine actuator and the flow rate of pressure oil to the cooling fan drive actuator.
第２発明は、第１発明において、前記可変容量型油圧ポンプの最大吐出量が、作業機駆動に必要な最大流量と冷却ファン駆動に必要な最大流量とを加算した流量よりも少ないものであり、
前記制御装置はさらに、前記油圧ポンプの吐出量が作業機駆動に必要な流量と冷却ファン駆動に必要な流量とを加算した流量よりも不足する場合には、作業機に必要な流量を優先的に供給し、残りの流量を冷却ファン駆動に供給するように圧油の流量制御をおこなうものである。
According to a second invention, in the first invention, the maximum discharge amount of the variable displacement hydraulic pump is less than a flow rate obtained by adding a maximum flow rate required for driving the work implement and a maximum flow rate required for driving the cooling fan. ,
The control device further gives priority to the flow rate required for the work implement when the discharge amount of the hydraulic pump is less than the flow rate required for driving the work implement and the flow rate required for driving the cooling fan. The flow rate of the pressure oil is controlled so that the remaining flow rate is supplied to the cooling fan drive.
第１発明によると、作業機アクチュエータと冷却ファン駆動用アクチュエータへ圧油を供給するポンプを共通のものとすることにより、ポンプ数を減らすことができる。また、このポンプを可変容量型とし、作業機アクチュエータへの圧油の流量と冷却ファン駆動用アクチュエータへの圧油の流量とを制御する制御装置を有することにより、ポンプからは常に必要な流量のみが吐出されるので、効率を向上できる。 According to the first invention, the number of pumps can be reduced by using a common pump for supplying pressure oil to the work machine actuator and the cooling fan driving actuator. In addition, this pump is of a variable capacity type and has a control device that controls the flow rate of pressure oil to the work implement actuator and the flow rate of pressure oil to the cooling fan drive actuator, so that only the necessary flow rate is always available from the pump. Is discharged, so that the efficiency can be improved.
第２発明によると、可変容量型油圧ポンプを、従来の作業機駆動に必要な最大流量と冷却ファン駆動に必要な最大流量とを単に加算した最大吐出量を有するものよりも小型化することができ、製作コストを低減できる。また、油圧ポンプの吐出量が作業機駆動に必要な流量と冷却ファン駆動に必要な流量とを加算した流量よりも不足する場合には、作業機に必要な流量を優先的に供給し、残りの流量を冷却ファン駆動に供給するため、作業機の作業能率を低下させずに作業できる。従って、特にブルドーザ等のように作業機操作時間が少ない作業車両では、冷却ファンの冷却能力を大きく低下させることがないため、特に好適である。 According to the second invention, the variable displacement hydraulic pump can be made smaller than the conventional one having the maximum discharge amount obtained by simply adding the maximum flow rate required for driving the work implement and the maximum flow rate required for driving the cooling fan. Manufacturing costs can be reduced. In addition, if the discharge rate of the hydraulic pump is less than the flow rate required for driving the work implement and the flow rate required for driving the cooling fan, the flow rate required for the work implement is preferentially supplied and the remaining Since the flow rate is supplied to the cooling fan drive, the work efficiency of the work machine can be reduced without deteriorating. Therefore, in particular, a work vehicle such as a bulldozer that has a short work machine operation time is particularly suitable because the cooling capacity of the cooling fan is not greatly reduced.
以下、本発明に係る作業車両の油圧回路の実施形態について図面を参照して説明する。尚、以下では、本発明の適用機例としてブルドーザを取り挙げて説明する。 DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a hydraulic circuit for a work vehicle according to the present invention will be described with reference to the drawings. In the following, a bulldozer will be described as an example of an application machine of the present invention.
図２及び図３に示すように、本発明が適用されるブルドーザ１は、車体フレーム２の下部に左右１対のクローラ式走行装置３，３を備え、車体フレーム２の後側上部に運転室４を備えている。エンジン１９と、ラジエータ及びオイルクーラ等の冷却装置１７とは前記車体フレーム２の内側前部に設けられており、冷却装置１７の冷却風の風下側近傍には冷却ファン１８が設けられている。冷却ファン１８は油圧モータ１０で回転駆動される。また、上面視Ｕ字型の作業機支持フレーム６は、その開口側を車両後方へ向け、該開口側の端部が車体フレーム２の左右側部に上下揺動自在に取り付けられている。そしてブレード５は、この作業機支持フレーム６の、車両前方を向いて左寄り前部に形成された前方突出部６ｅの前端部に、自在連結部６ａを介して上下方向軸回りに前後傾動（以下、アングルという。）自在に、及び前後方向軸回りに左右傾動（以下、チルトという。）自在に装着されている。 As shown in FIGS. 2 and 3, a bulldozer 1 to which the present invention is applied includes a pair of left and right crawler type traveling devices 3, 3 at a lower part of a body frame 2, and a driver's cab at the rear upper part of the body frame 2. 4 is provided. The engine 19 and a cooling device 17 such as a radiator and an oil cooler are provided at the inner front portion of the vehicle body frame 2, and a cooling fan 18 is provided near the leeward side of the cooling air of the cooling device 17. The cooling fan 18 is rotationally driven by the hydraulic motor 10. Further, the U-shaped work implement support frame 6 in a top view has its opening side directed toward the rear of the vehicle, and ends of the opening side are attached to the left and right side portions of the body frame 2 so as to be swingable up and down. Then, the blade 5 tilts forward and backward around the vertical axis via the universal connection portion 6a to the front end portion of the front projecting portion 6e formed on the front left side of the work machine support frame 6 facing the front of the vehicle (hereinafter referred to as the vertical axis). , And can be freely tilted to the left and right (hereinafter referred to as tilt) around the longitudinal axis.
左右１対のリフトシリンダ７，７は、それぞれ作業機支持フレーム６の開口側の左右上面部と車体フレーム２の左右側面部との間に取り付けられ、作業機支持フレーム６を昇降駆動するものである。また、ブレード５をアングル駆動するアングルシリンダ８は、作業機支持フレーム６の前記前方突出部６ｅとブレード５の背面の右側端部との間に取り付けられている。また、作業機支持フレーム６の前記前方突出部６ｅの上部に設けられたブラケット６ｂと、ブレード５とは、前記自在連結部６ａの上方に位置する自在連結部６ｄを介してリンク６ｃで連結されている。ブレード５をチルト駆動するチルトシリンダ９は、前記リンク６ｃの一端部と作業機支持フレーム６の開口側左部との間に取り付けられている。 The pair of left and right lift cylinders 7 and 7 are respectively mounted between the left and right upper surface portions on the opening side of the work implement support frame 6 and the left and right side portions of the vehicle body frame 2 to drive the work implement support frame 6 up and down. is there. An angle cylinder 8 that drives the blade 5 at an angle is attached between the forward projecting portion 6 e of the work machine support frame 6 and the right end portion of the back surface of the blade 5. Further, the bracket 6b provided on the upper part of the forward projecting portion 6e of the work implement support frame 6 and the blade 5 are connected by a link 6c via a universal connection portion 6d located above the universal connection portion 6a. ing. A tilt cylinder 9 for tilting the blade 5 is attached between one end of the link 6 c and the left side on the opening side of the work implement support frame 6.
図１は、実施形態に係るブルドーザの油圧回路のブロック図である。冷却ファン駆動用アクチュエータである前記油圧モータ１０は、方向切換弁１３によってその圧油の流量及び方向を制御されている。また、同様に、前記リフトシリンダ７，７、チルトシリンダ９及びアングルシリンダ８の各作業機アクチュエータは、その圧油の流量及び方向をそれぞれ方向切換弁１４，１５，１６によって制御されている。これらの方向切換弁１３，１４，１５，１６は、パイロット操作式の方向切換弁で構成されている。 FIG. 1 is a block diagram of a hydraulic circuit of a bulldozer according to an embodiment. The hydraulic motor 10, which is a cooling fan driving actuator, is controlled in its flow rate and direction by a direction switching valve 13. Similarly, the working machine actuators of the lift cylinders 7, 7, the tilt cylinder 9 and the angle cylinder 8 are controlled by the direction switching valves 14, 15, 16 respectively for the flow rate and direction of the pressure oil. These directional control valves 13, 14, 15, 16 are constituted by pilot operated directional control valves.
電磁式パイロット操作弁２１ａ，２１ｂは、そのソレノイド部にコントローラ２０からの制御信号を入力し、該制御信号の大きさに応じたパイロット圧を出力するものである。電磁式パイロット操作弁２１ａ，２１ｂの出力パイロット圧は、パイロット管路３１ａ，３１ｂを介して前記方向切換弁１３のパイロット操作部に入力されている。また、パイロット操作弁２２ａ，２２ｂ，２３ａ，２３ｂ，２４ａ，２４ｂは、それぞれリフト操作レバー４１、チルト操作レバー４２及びアングル操作レバー４３の操作量に応じたパイロット圧を出力するものであり、それぞれパイロット管路３２ａ，３２ｂ，３３ａ，３３ｂ，３４ａ，３４ｂを介して方向切換弁１４，１５，１６のパイロット操作部に接続されている。 The electromagnetic pilot operation valves 21a and 21b are for inputting a control signal from the controller 20 to the solenoid portion and outputting a pilot pressure corresponding to the magnitude of the control signal. The output pilot pressure of the electromagnetic pilot operation valves 21a and 21b is input to the pilot operation portion of the direction switching valve 13 through the pilot pipe lines 31a and 31b. The pilot operation valves 22a, 22b, 23a, 23b, 24a, and 24b output pilot pressures corresponding to the operation amounts of the lift operation lever 41, the tilt operation lever 42, and the angle operation lever 43, respectively. The pipes 32a, 32b, 33a, 33b, 34a, and 34b are connected to the pilot operating portions of the direction switching valves 14, 15, and 16 respectively.
また、前記パイロット管路３２ａ，３２ｂ，３３ａ，３３ｂ，３４ａ，３４ｂには、パイロット圧を検出する圧力センサ２５ａ，２５ｂ，２６ａ，２６ｂ，２７ａ，２７ｂがそれぞれ設けられており、これらの圧力センサ２５ａ，２５ｂ，２６ａ，２６ｂ，２７ａ，２７ｂの検出信号はそれぞれリフト操作レバー４１、チルト操作レバー４２及びアングル操作レバー４３の操作量信号としてコントローラ２０に入力されている。 The pilot pipes 32a, 32b, 33a, 33b, 34a, 34b are provided with pressure sensors 25a, 25b, 26a, 26b, 27a, 27b, respectively, for detecting the pilot pressure, and these pressure sensors 25a. 25b, 26a, 26b, 27a, and 27b are input to the controller 20 as operation amount signals of the lift operation lever 41, the tilt operation lever 42, and the angle operation lever 43, respectively.
エンジン１９（図２参照）で回転駆動される可変容量型の油圧ポンプ１１の制御回路は、油圧ポンプ１１の斜板角（吐出量に対応する。）が、各方向切換弁１３，１４，１５，１６の開口量（すなわち要求流量）に応じて制御される、所謂ロードセンシング回路となっている（但し、図１のブロック図にはそのロードセンシング回路の詳細図示を省いている。）。つまり、ポンプ吐出圧と負荷圧との差圧（各方向切換弁１３，１４，１５，１６の前後の差圧）が、負荷圧に関係なく同一になるように油圧ポンプ１１の斜板角を調整する斜板駆動シリンダ１２ａを制御している。各方向切換弁１３，１４，１５，１６の開口量が小さければ、同一の差圧を発生させるのに少ない流量しか必要とせず、逆に開口量が大きければ、同一の差圧を発生させるのに大流量を必要とする。したがって、上記ロードセンシング回路により、油圧ポンプ１１の斜板角は、常に各方向切換弁１３，１４，１５，１６の開口量に応じた流量を吐出するように自動的に調整されることとなる。なお、ロードセンシングによる油圧ポンプ１１の斜板角の制御は、油圧サーボ、電気サーボ、電気−油圧サーボなどの方法を用いることができるが、これらの技術は公知であるので、詳しい説明は省略する。ここでは、油圧回路を制御するための上記油圧サーボ、電気サーボ、電気−油圧サーボなどの各構成油圧機器及びコントローラ２０を含めた全体を制御装置５０と呼ぶ。 In the control circuit of the variable displacement hydraulic pump 11 that is rotationally driven by the engine 19 (see FIG. 2), the swash plate angle (corresponding to the discharge amount) of the hydraulic pump 11 is set to each of the directional control valves 13, 14, 15. , 16 is a so-called load sensing circuit controlled according to the opening amount (that is, the required flow rate) (however, the load sensing circuit is not shown in detail in the block diagram of FIG. 1). That is, the swash plate angle of the hydraulic pump 11 is set so that the differential pressure between the pump discharge pressure and the load pressure (differential pressure before and after each direction switching valve 13, 14, 15, 16) becomes the same regardless of the load pressure. The swash plate drive cylinder 12a to be adjusted is controlled. If the opening amount of each directional control valve 13, 14, 15, 16 is small, only a small flow rate is required to generate the same differential pressure. Conversely, if the opening amount is large, the same differential pressure is generated. Requires a large flow rate. Therefore, the swash plate angle of the hydraulic pump 11 is automatically adjusted by the load sensing circuit so as to always discharge a flow rate corresponding to the opening amount of each direction switching valve 13, 14, 15, 16. . Note that the control of the swash plate angle of the hydraulic pump 11 by load sensing can use methods such as a hydraulic servo, an electric servo, and an electro-hydraulic servo. . Here, the entirety including the constituent hydraulic devices such as the hydraulic servo, the electric servo, the electro-hydraulic servo, and the controller 20 for controlling the hydraulic circuit is referred to as a control device 50.
また油圧ポンプ１１は、その最大吐出量Ｑmax が、作業機駆動に必要な最大流量ＱＷmax （リフト操作レバー４１、チルト操作レバー４２及びアングル操作レバー４３の各操作量が全て最大のときの流量）と冷却ファンを最大回転数で駆動するときに必要な最大流量ＱＦmax
とを単に加算した吐出量よりも小さいものが用いられている。すなわち、最大吐出量Ｑmax は、例えば次式「Ｑmax ＝ＱＷmax ＋ＱＦmax ×α、但しα＝０．２〜０．５」を満たすように選定される。
In the hydraulic pump 11, the maximum discharge amount Qmax is the maximum flow rate QWmax (the flow rate when the operation amounts of the lift operation lever 41, the tilt operation lever 42, and the angle operation lever 43 are all the maximum) necessary for driving the work machine. Maximum flow rate QFmax required to drive the cooling fan at maximum speed
Is smaller than the discharge amount obtained by simply adding. That is, the maximum discharge amount Qmax is selected so as to satisfy, for example, the following expression “Qmax = QWmax + QFmax × α, where α = 0.2 to 0.5”.
コントローラ２０は、例えばマイクロコンピュータ等の演算装置から構成されており、前記圧力センサ２５ａ，２５ｂ，２６ａ，２６ｂ，２７ａ，２７ｂの検出信号、すなわちリフト操作レバー４１、チルト操作レバー４２及びアングル操作レバー４３の操作量に基づき、リフトシリンダ７，７、チルトシリンダ９及びアングルシリンダ８の各作業機アクチュエータへの供給流量を求め、作業機駆動に要する全流量（以下、作業機流量と言う。）ＱＷを演算によって求める。なお、コントローラ２０は、その記憶装置内に、圧力センサ２５ａ，２５ｂ，２６ａ，２６ｂ，２７ａ，２７ｂの検出圧力値とリフトシリンダ７，７、チルトシリンダ９及びアングルシリンダ８への供給流量との対応を表すデータテーブル、又は演算式を記憶している。 The controller 20 is constituted by an arithmetic unit such as a microcomputer, for example, and the detection signals of the pressure sensors 25a, 25b, 26a, 26b, 27a, 27b, that is, the lift operation lever 41, the tilt operation lever 42, and the angle operation lever 43 are detected. Based on the manipulated variable, the supply flow rates to the work machine actuators of the lift cylinders 7, 7, the tilt cylinder 9 and the angle cylinder 8 are obtained, and the total flow rate (hereinafter referred to as work machine flow rate) QW required to drive the work machine is obtained. Calculate by calculation. In the storage device, the controller 20 correlates the detected pressure values of the pressure sensors 25a, 25b, 26a, 26b, 27a, and 27b with the supply flow rates to the lift cylinders 7, 7, the tilt cylinder 9, and the angle cylinder 8. A data table or an arithmetic expression is stored.
また、コントローラ２０は、エンジン水温センサ３６、作動油温センサ３７及びエンジン回転数センサ３８でそれぞれ検出したエンジン水温、作動油温及びエンジン回転数を入力し、これらの入力値に応じてエンジン水温、作動油温が許容値以下になるように冷却ファン１８の目標回転数を演算により求め、該目標回転数に相当する油圧モータ１０への流量（以下、ファン流量と言う。）ＱＦを求める。そして、求めた前記作業機流量ＱＷおよびファン流量ＱＦの合計流量と、予め設定されている油圧ポンプ１１の最大吐出量Ｑmax とを比較演算し、その比較結果に基づいて次のように電磁式パイロット操作弁２１ａ，２１ｂに制御信号を出力して、方向切換弁１３の開口量つまりファン流量を制御している。 In addition, the controller 20 inputs the engine water temperature, the hydraulic oil temperature, and the engine speed detected by the engine water temperature sensor 36, the hydraulic oil temperature sensor 37, and the engine speed sensor 38, respectively, and the engine water temperature, The target rotational speed of the cooling fan 18 is obtained by calculation so that the hydraulic oil temperature is lower than the allowable value, and the flow rate (hereinafter referred to as fan flow rate) QF to the hydraulic motor 10 corresponding to the target rotational speed is obtained. Then, the calculated total flow rate of the work implement flow rate QW and the fan flow rate QF is compared with the preset maximum discharge amount Qmax of the hydraulic pump 11, and based on the comparison result, the electromagnetic pilot is as follows. A control signal is output to the operation valves 21a and 21b to control the opening amount of the direction switching valve 13, that is, the fan flow rate.
（１）ＱＷ＋ＱＦ≦Ｑmax のとき
コントローラ２０は、前記求めたファン流量ＱＦを油圧モータ１０に供給するように、電磁式パイロット操作弁２１ａ，２１ｂを介して方向切換弁１３の開口量を制御する。
（２）ＱＷ＋ＱＦ＞Ｑmax のとき、
コントローラ２０は、前記作業機流量ＱＷとファン流量ＱＦとの合計流量が可変容量型油圧ポンプ１１の最大吐出量Ｑmax よりも大きい、すなわちポンプ吐出量が不足しているときには、ファン流量として「Ｑmax −ＱＷ」を演算により求め、この「Ｑmax −ＱＷ」に等しい流量を油圧モータ１０に供給するように、電磁式パイロット操作弁２１ａ，２１ｂを介して方向切換弁１３の開口量を制御する。これにより、作業機流量ＱＷの供給が優先され、冷却ファン１８は必要ファン流量ＱＦよりも少ない流量「Ｑmax
−ＱＷ」に対応する回転数で回転することになる。
(1) When QW + QF ≦ Qmax The controller 20 controls the opening amount of the direction switching valve 13 via the electromagnetic pilot operation valves 21a and 21b so as to supply the obtained fan flow rate QF to the hydraulic motor 10.
(2) When QW + QF> Qmax,
When the total flow rate of the work implement flow rate QW and the fan flow rate QF is larger than the maximum discharge amount Qmax of the variable displacement hydraulic pump 11, that is, the controller 20 sets the fan flow rate as “Qmax− "QW" is obtained by calculation, and the opening amount of the direction switching valve 13 is controlled via the electromagnetic pilot operated valves 21a and 21b so as to supply the hydraulic motor 10 with a flow rate equal to "Qmax-QW". Accordingly, the supply of the work machine flow rate QW is prioritized, and the cooling fan 18 has a flow rate “Qmax smaller than the required fan flow rate QF.
The rotation speed corresponds to “−QW”.
なお、上記（１）（２）のいずれの場合でも、作業機アクチュエータ駆動用の方向切換弁１４，１５，１６の開口量は前述のロードセンシング回路によってそれぞれパイロット操作弁２２ａ，２２ｂ，２３ａ，２３ｂ，２４ａ，２４ｂの操作パイロット圧に応じて自動的に調整されているため、作業機へは常に前記作業機流量ＱＷが供給される。 In both cases (1) and (2), the opening amounts of the direction switching valves 14, 15, and 16 for driving the work machine actuator are respectively controlled by the pilot operation valves 22a, 22b, 23a, and 23b by the load sensing circuit. , 24a, 24b is automatically adjusted according to the operation pilot pressure, so that the work implement flow rate QW is always supplied to the work implement.
上記実施形態によると、作業機アクチュエータに供給する圧油と冷却ファン駆動用アクチュエータに供給する圧油とを両者共通の可変容量型油圧ポンプ１１で吐出しているので、油圧ポンプの個数が少なくなる。可変容量型油圧ポンプ１１の吐出量は、冷却ファン駆動用及び作業機駆動用の方向切換弁１３，１４，１５，１６の開口量に応じた流量を吐出するように自動的に制御されている。これにより、作業機が操作されてないときには、可変容量型油圧ポンプ１１の吐出量はファン流量のみになり、よって損失を非常に小さくすることができ、効率を向上できる。 According to the above embodiment, since the pressure oil supplied to the work implement actuator and the pressure oil supplied to the cooling fan drive actuator are discharged by the common variable displacement hydraulic pump 11, the number of hydraulic pumps is reduced. . The discharge amount of the variable displacement hydraulic pump 11 is automatically controlled so as to discharge a flow rate corresponding to the opening amount of the direction switching valves 13, 14, 15, 16 for driving the cooling fan and driving the work machine. . As a result, when the work implement is not operated, the discharge amount of the variable displacement hydraulic pump 11 is only the fan flow rate, so that the loss can be greatly reduced and the efficiency can be improved.
そして、コントローラ２０は、可変容量型油圧ポンプ１１の最大吐出量Ｑmax が作業機流量ＱＷとファン流量ＱＦとの合計流量よりも不足しているときには、作業機流量ＱＷの供給を優先し、冷却ファン駆動用の方向切換弁１３の開口量を制御してファン流量が「Ｑmax
−ＱＷ」になるようにしている。これによって、作業機駆動が優先され、冷却ファン１８の回転数は減少するが、特にブルドーザの場合は押土作業やレベリング作業が主であるから、作業機の作動時間が短く、全体的に走行が主に行われるため、一時的に冷却ファン駆動用の流量を減少させても全体的な冷却能力への影響は小さい。可変容量型油圧ポンプ１１は、その最大吐出量Ｑmax が、作業機駆動に必要な最大流量ＱＷmax と冷却ファン１８を最大回転数で駆動するときに必要な最大流量ＱＦmax とを単に加算した吐出量よりも小さいものとしているため、小型の油圧ポンプを用いることができる。
When the maximum discharge amount Qmax of the variable displacement hydraulic pump 11 is less than the total flow rate of the work implement flow rate QW and the fan flow rate QF, the controller 20 gives priority to the supply of the work implement flow rate QW, and the cooling fan The fan flow rate is set to “Qmax by controlling the opening amount of the driving direction switching valve 13
-QW ". As a result, the work machine drive is given priority and the number of rotations of the cooling fan 18 is reduced. In particular, in the case of a bulldozer, since the main work is earthing work and leveling work, the work machine operation time is short, and the entire machine travels. Therefore, even if the flow rate for driving the cooling fan is temporarily reduced, the influence on the overall cooling capacity is small. The variable displacement hydraulic pump 11 has a maximum discharge amount Qmax based on a discharge amount obtained by simply adding the maximum flow rate QWmax required for driving the work implement and the maximum flow rate QFmax required for driving the cooling fan 18 at the maximum rotation speed. Therefore, a small hydraulic pump can be used.
以上、本発明の実施形態を説明したが、これらは本発明の説明のための例示であり、これらの実施形態のみに発明の範囲を限定する趣旨ではない。従って、本発明は、その要旨を逸脱することなく、他の様々な形態で実施することは可能である。 As mentioned above, although embodiment of this invention was described, these are the illustrations for description of this invention, and are not the meaning which limits the scope of the invention only to these embodiment. Therefore, the present invention can be implemented in various other forms without departing from the gist thereof.
例えば、作業機操作レバー４１，４２，４３でパイロット操作弁を操作する構成の油圧回路例で説明したが、これに限らず、作業機操作レバーは電気式レバーで構成し、このレバーの操作量信号をコントローラ２０に入力し、コントローラ２０が操作量信号に応じて電磁式パイロット操作弁に指令を出力して作業機駆動用方向切換弁を制御する構成の回路であっても、本発明を適用可能である。
また、作業機流量ＱＷは、各作業機操作のパイロット圧に基づき演算により求められているが、各作業機操作レバー４１，４２，４３（上記電気式レバーの場合も含む。）の操作ストロークに基づき演算により求めるようにしてもよい。
For example, the example of the hydraulic circuit configured to operate the pilot operating valve with the work implement operating levers 41, 42, and 43 has been described. The present invention is applied even to a circuit having a configuration in which a signal is input to the controller 20 and the controller 20 outputs a command to the electromagnetic pilot operation valve according to the operation amount signal to control the directional control valve for driving the work machine. Is possible.
Further, the work implement flow rate QW is obtained by calculation based on the pilot pressure of each work implement operation, but the operation stroke of each work implement operation lever 41, 42, 43 (including the case of the electric lever) is also included. You may make it require | calculate based on a calculation.
さらに、油圧ポンプ１１はエンジンで回転駆動されるものに限らず、電動機で回転駆動される構成であっても構わない。
また、本発明は、ブルドーザに限らず、ホイルローダ、その他の作業車両にも適用可能である。
Furthermore, the hydraulic pump 11 is not limited to be driven to rotate by the engine, and may be configured to be driven to rotate by an electric motor.
Moreover, this invention is applicable not only to a bulldozer but to a wheel loader and other work vehicles.
１…ブルドーザ、３…クローラ式走行装置、５…ブレード、６…作業機支持フレーム、７…リフトシリンダ、８…アングルシリンダ、９…チルトシリンダ、１０…油圧モータ（冷却ファン駆動用アクチュエータ）、１１…油圧ポンプ、１３，１４，１５，１６…方向切換弁、１７…冷却装置、１８…冷却ファン、２０…コントローラ、２１ａ，２１ｂ…電磁式パイロット操作弁、２２ａ，２２ｂ，２３ａ，２３ｂ，２４ａ，２４ｂ…パイロット操作弁、２５ａ，２５ｂ，２６ａ，２６ｂ，２７ａ，２７ｂ…圧力センサ、５０…制御装置。
DESCRIPTION OF SYMBOLS 1 ... Bulldozer, 3 ... Crawler type traveling device, 5 ... Blade, 6 ... Work machine support frame, 7 ... Lift cylinder, 8 ... Angle cylinder, 9 ... Tilt cylinder, 10 ... Hydraulic motor (cooling fan drive actuator), 11 ... Hydraulic pump, 13, 14, 15, 16 ... Direction switching valve, 17 ... Cooling device, 18 ... Cooling fan, 20 ... Controller, 21a, 21b ... Electromagnetic pilot operated valve, 22a, 22b, 23a, 23b, 24a, 24b ... Pilot operation valve, 25a, 25b, 26a, 26b, 27a, 27b ... Pressure sensor, 50 ... Control device.
Claims (2)
作業機アクチュエータと、
冷却ファン駆動用アクチュエータと、
前記作業機アクチュエータ及び前記冷却ファン駆動用アクチュエータの両方へ圧油を供給する共通の可変容量型油圧ポンプと、
前記作業機アクチュエータへの圧油の流量及び前記冷却ファン駆動用アクチュエータへの圧油の流量を制御する制御装置とを備える
ことを特徴とする作業車両の油圧回路。 In the hydraulic circuit of a work vehicle,
A work machine actuator;
An actuator for driving a cooling fan;
A common variable displacement hydraulic pump that supplies pressure oil to both the work implement actuator and the cooling fan drive actuator;
A hydraulic circuit for a work vehicle, comprising: a control device that controls a flow rate of pressure oil to the work machine actuator and a flow rate of pressure oil to the cooling fan driving actuator.
前記制御装置はさらに、前記油圧ポンプの吐出量が作業機駆動に必要な流量と冷却ファン駆動に必要な流量とを加算した流量よりも不足する場合には、作業機に必要な流量を優先的に供給し、残りの流量を冷却ファン駆動に供給するように圧油の流量制御をおこなうものである
ことを特徴とする請求項１記載の作業車両の油圧回路。
The maximum discharge amount of the variable displacement hydraulic pump is less than the flow rate obtained by adding the maximum flow rate required for driving the work implement and the maximum flow rate required for driving the cooling fan,
The control device further gives priority to the flow rate required for the work implement when the discharge amount of the hydraulic pump is less than the flow rate required for driving the work implement and the flow rate required for driving the cooling fan. 2. The hydraulic circuit for a work vehicle according to claim 1, wherein the flow rate of the pressure oil is controlled so that the remaining flow rate is supplied to the cooling fan drive.
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|---|---|---|---|
| JP2004162676A JP2005344766A (en) | 2004-06-01 | 2004-06-01 | Oil-hydraulic circuit of work vehicle |
| PCT/JP2005/010062 WO2006008875A1 (en) | 2004-06-01 | 2005-06-01 | Hydraulic circuit for working vehicle |
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| JP2004162676A JP2005344766A (en) | 2004-06-01 | 2004-06-01 | Oil-hydraulic circuit of work vehicle |
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| WO2008023516A1 (en) * | 2006-08-24 | 2008-02-28 | Komatsu Ltd. | Fan drive system |
| WO2020100613A1 (en) * | 2018-11-15 | 2020-05-22 | 株式会社小松製作所 | Work machine |
| WO2023153095A1 (en) * | 2022-02-14 | 2023-08-17 | コベルコ建機株式会社 | Hydraulic drive device and construction machine provided with same |
| WO2024048527A1 (en) * | 2022-08-29 | 2024-03-07 | 日立建機株式会社 | Transportation vehicle |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6793873B2 (en) * | 2018-09-21 | 2020-12-02 | 日立建機株式会社 | Hydraulic drive fan control device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3664129A (en) * | 1968-05-08 | 1972-05-23 | Hyster Co | Hydraulic cooling system |
| JP2001003385A (en) * | 1999-05-04 | 2001-01-09 | Caterpillar Inc | Power control system of machine |
| JP2004508480A (en) * | 2000-09-08 | 2004-03-18 | テレックス ジャーマニー ゲゼルシャフト ミット ベシュレンクテル ハフツング ウント コンパニー コマンディートゲゼルシャフト | Method and apparatus for controlling a fan drive of an internal combustion engine in construction and / or work machines |
| JP2004239389A (en) * | 2003-02-07 | 2004-08-26 | Shin Caterpillar Mitsubishi Ltd | Oil cooler control method and oil cooler control unit |
| JP2004316814A (en) * | 2003-04-17 | 2004-11-11 | Shin Caterpillar Mitsubishi Ltd | Method and apparatus for controlling fluid viscosity |
-
2004
- 2004-06-01 JP JP2004162676A patent/JP2005344766A/en active Pending
-
2005
- 2005-06-01 WO PCT/JP2005/010062 patent/WO2006008875A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3664129A (en) * | 1968-05-08 | 1972-05-23 | Hyster Co | Hydraulic cooling system |
| JP2001003385A (en) * | 1999-05-04 | 2001-01-09 | Caterpillar Inc | Power control system of machine |
| JP2004508480A (en) * | 2000-09-08 | 2004-03-18 | テレックス ジャーマニー ゲゼルシャフト ミット ベシュレンクテル ハフツング ウント コンパニー コマンディートゲゼルシャフト | Method and apparatus for controlling a fan drive of an internal combustion engine in construction and / or work machines |
| JP2004239389A (en) * | 2003-02-07 | 2004-08-26 | Shin Caterpillar Mitsubishi Ltd | Oil cooler control method and oil cooler control unit |
| JP2004316814A (en) * | 2003-04-17 | 2004-11-11 | Shin Caterpillar Mitsubishi Ltd | Method and apparatus for controlling fluid viscosity |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008023516A1 (en) * | 2006-08-24 | 2008-02-28 | Komatsu Ltd. | Fan drive system |
| JPWO2008023516A1 (en) * | 2006-08-24 | 2010-01-07 | 株式会社小松製作所 | Fan drive system |
| JP4588089B2 (en) * | 2006-08-24 | 2010-11-24 | 株式会社小松製作所 | Fan drive system |
| WO2020100613A1 (en) * | 2018-11-15 | 2020-05-22 | 株式会社小松製作所 | Work machine |
| JP2020085016A (en) * | 2018-11-15 | 2020-06-04 | 株式会社小松製作所 | Work machine |
| CN112739874A (en) * | 2018-11-15 | 2021-04-30 | 株式会社小松制作所 | Working machine |
| CN112739874B (en) * | 2018-11-15 | 2022-06-28 | 株式会社小松制作所 | Working machine |
| US11384512B2 (en) | 2018-11-15 | 2022-07-12 | Komatsu Ltd. | Work machine |
| JP7257132B2 (en) | 2018-11-15 | 2023-04-13 | 株式会社小松製作所 | working machine |
| WO2023153095A1 (en) * | 2022-02-14 | 2023-08-17 | コベルコ建機株式会社 | Hydraulic drive device and construction machine provided with same |
| WO2024048527A1 (en) * | 2022-08-29 | 2024-03-07 | 日立建機株式会社 | Transportation vehicle |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2006008875A1 (en) | 2006-01-26 |
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