JP2017125353A5

JP2017125353A5 -

Info

Publication number: JP2017125353A5
Application number: JP2016005459A
Authority: JP
Filing date: 2016-01-14
Publication date: 2019-02-28
Anticipated expiration: 2036-01-14

Description

本発明によれば、リフトアームの上げ操作時に、リフトシリンダボトム室への作動油の供給に加え、チルトシリンダボトム室にも作動油を供給させる構成にしたことにより、リフトシリンダの伸長にあわせてチルトシリンダも伸長されるので、バケットのチルト角が安定する。 According to the present invention, when raising operation of the lift arm, in addition to the supply of hydraulic oil to the lift cylinder bottom chamber, by which a configuration that makes supply also hydraulic oil to the tilt cylinder bottom chamber, in accordance with the extension of the lift cylinder Since the tilt cylinder is also extended, the tilt angle of the bucket is stabilized.

ステップＳ１０７において、チルト／ダンプ操作圧が所定の閾値以上であるか否か、すなわちチルト/ダンプ操作が行われているか否かを判断する。チルト／ダンプ操作圧が所定の閾値未満であると判断する場合はステップＳ１０８に進み、チルト／ダンプ操作圧が所定の閾値以上であると判断する場合はステップＳ１０３に進む。
ステップＳ１０８において、第１連通/遮断弁１７に第２位置、すなわち開位置への動作指令を出力して、図７により動作が表されるプログラムを終了する。ステップＳ１０８に進む状態は、バケット作業に適したアタッチメント角度特性となるようなリフト操作、バケット操作が行われる場合である。
なお、ステップＳ１０２、Ｓ１０５、Ｓ１０７において用いた所定の閾値は、個別の値である。 In step S107, it is determined whether or not the tilt / dump operation pressure is greater than or equal to a predetermined threshold, that is, whether or not the tilt / dump operation is being performed. When it is determined that the tilt / dump operation pressure is less than the predetermined threshold, the process proceeds to step S108, and when it is determined that the tilt / dump operation pressure is equal to or greater than the predetermined threshold, the process proceeds to step S103.
In step S108, an operation command to the second position, that is, the open position is output to the first communication / shutoff valve 17, and the program whose operation is represented by FIG. 7 is terminated. The state that proceeds to step S108 is a case where a lift operation and a bucket operation are performed so as to obtain an attachment angle characteristic suitable for bucket work.
Note that the predetermined threshold values used in steps S102, S105, and S107 are individual values.

引き続き、バケット８がチルトストッパ作動状態になるまで、チルトとリフトアーム上げの複合動作を行う。バケット８がチルトストッパ作動状態になると、オペレータはチルトおよびリフトアーム上げ操作を停止し、図８（ａ）に示すように走行動作にて土砂を運搬する。オペレータがチルトおよびリフトアーム上げ操作を停止する直前の状態では、チルトストッパセンサの出力が閾値を上回るが（図７のステップＳ１０２：ＹＥＳ）、チルト／ダンプ操作圧が閾値より大きいと判断されるため（図７のステップＳ１０７：ＮＯ）。コントローラは第１連通/遮断弁１７に対して第１位置の指令出力を継続する。 Subsequently, a combined operation of tilt and lift arm raising is performed until the bucket 8 is in the tilt stopper operating state. When the bucket 8 is tilted stopper operating state, the operator stops the tilt and lift arm raising operation, carrying earth and sand by the running operation as shown in FIG. 8 (a). In the state immediately before the operator stops the tilt and lift arm raising operation, the output of the tilt stopper sensor exceeds the threshold (step S102: YES in FIG. 7), but it is determined that the tilt / dump operation pressure is greater than the threshold. (Step S107 in FIG. 7: NO). The controller continues to output the first position command to the first communication / shutoff valve 17.

ボトム室連通／遮断弁４２は、遮断位置において、リフトシリンダボトム室１３ａを油圧源に接続するボトム室油路４２ｂを有し、連通位置において、リフトシリンダボトム室１３ａとチルトシリンダボトム室１４ａを圧油源に接続するボトム室側リフト/チルト連通油路４２ｃを有する。ボトム室側リフト/チルト連通油路４２ｃは、リフトシリンダ１３を収縮させる向きの流れを防止するボトム室チェック弁４２ａを有する。 The bottom chamber communication / shutoff valve 42 has a bottom chamber oil passage 42b that connects the lift cylinder bottom chamber 13a to a hydraulic pressure source at the shut-off position, and pressurizes the lift cylinder bottom chamber 13a and the tilt cylinder bottom chamber 14a at the communication position. A bottom chamber side lift / tilt communication oil passage 42c connected to the oil source is provided. The bottom chamber side lift / tilt communication oil passage 42 c includes a bottom chamber check valve 42 a that prevents a flow in a direction in which the lift cylinder 13 is contracted .

ロッド室連通／遮断弁４３は、遮断位置において、リフトシリンダロッド室１３ｂを油圧源に接続するロッド室油路４３ｂを有し、連通位置において、リフトシリンダロッド室１３ｂとチルトシリンダロッド室１４ｂを圧油源に接続するロッド室側リフト/チルト連通油路４３ｃを有する。ロッド室側リフト/チルト連通油路４３ｃは、リフトシリンダ１３を収縮させる向きの流れを防止するロッド室チェック弁４３ａを有する。 The rod chamber communication / shutoff valve 43 has a rod chamber oil passage 43b that connects the lift cylinder rod chamber 13b to a hydraulic pressure source at the shut-off position, and pressurizes the lift cylinder rod chamber 13b and the tilt cylinder rod chamber 14b at the communication position. It has a rod chamber side lift / tilt communication oil passage 43c connected to the oil source. The rod chamber side lift / tilt communication oil passage 43c includes a rod chamber check valve 43a that prevents a flow in a direction in which the lift cylinder 13 is contracted .

ロッド室連通／遮断弁４３の第１位置は、リフトスプール３０の二次側をリフトシリンダロッド室１３ｂに接続させ、リフトシリンダロッド室１３ｂとチルトシリンダロッド室１４ｂとの連通を遮断する。ロッド室連通／遮断弁４３の第２位置は、ロッド室チェック弁４３ａによりリフトシリンダロッド室１３ｂへの圧油の流入を遮断する。 The first position of the rod chamber communication / shut-off valve 43 connects the secondary side of the lift spool 30 to the lift cylinder rod chamber 13b and blocks communication between the lift cylinder rod chamber 13b and the tilt cylinder rod chamber 14b. Second position of the rod chamber communication / shutoff valve 43, it shuts off the flow of pressure oil to the lift cylinder rod chamber 13b by the rod chamber check valve 43a.

すなわち、リフトシリンダボトム室１３ａに供給される圧油はチルトシリンダボトム室１４ａへも供給され、チルトシリンダ１４には伸び方向の推力が発生する。この結果、ダンプ側に姿勢が変わろうとするバケット８は、チルトストッパ作動状態を保つ。チルトシリンダ１４の伸長によってロッド側から排出された油は、ロッド室連通／遮断弁４３、およびコントロール弁１５を通ってタンク２１に戻る。そのままリフトアーム上げ操作を継続すると、バケット８の姿勢がチルトストッパ作動状態ではない姿勢となる。 That is, the pressure oil supplied to the lift cylinder bottom chamber 13a is also supplied to the tilt cylinder bottom chamber 14a, and the tilt cylinder 14 generates a thrust in the extending direction. As a result, the bucket 8 whose posture is about to change to the dump side maintains the tilt stopper operating state. Oil discharged from the rod side by the extension of the tilt cylinder 14 is returned to the tank 21 through the Rod chamber communication / shutoff valve 43 and control valve 15. If the lift arm raising operation is continued as it is, the posture of the bucket 8 becomes a posture that is not in the tilt stopper operating state.

（３）第３実施形態のホイールローダ１の荷役装置５において、ボトム室側リフト/チルト連通油路とロッド室側リフト/チルト連通油路はそれぞれ、リフトシリンダボトム室１３ａからの圧油の流出を阻止するボトム室チェック弁４２ａ、および、チルトシリンダロッド室１４ｂからリフトシリンダロッド室１３ｂへの圧油の流入を防止するロッド室チェック弁４３ａを有する。
このような逆流防止用のチェック弁４２ｂ、４３ｂにより、リフトシリンダ１３を収縮させる向きの流れが防止され、不所望なリフトアーム１０の落下を防止できる。
さらに、以下に説明する第３実施形態に特有の効果を有する。 (3) In the cargo handling device 5 of the wheel loader 1 of the third embodiment, each bottom chamber side lift / tilt communicating oil passage and the rod chamber side lift / tilt communicating oil passage, the pressure oil in the lift cylinder bottom chamber 13a or al bottom chamber check valve 42a for preventing the outflow, and a rod chamber check valve 43a for preventing the influx of pressurized oil from the Tilt cylinder rod chamber 1 4 b to riff preparative cylinder rod chamber 1 3 b.
By such check valves 42b and 43b for preventing backflow, a flow in a direction in which the lift cylinder 13 is contracted is prevented, and an undesired drop of the lift arm 10 can be prevented.
Furthermore, it has an effect peculiar to 3rd Embodiment demonstrated below.

（第３実施形態に特有の効果）
図１３は、第３実施形態に特有の効果を説明する図である。
第１連通/遮断弁１７が第２位置である連通位置で固着すると、第１、第２実施の形態では、図１３に示すように、リフトシリンダ１３とチルトシリンダ１４のボトム室間、ロッド室間が常に連通した状態になる。さらに、チルトストッパ非作動状態で、リフトシリンダ１３の保持圧がチルトシリンダ１４の保持圧より高いと、リフトシリンダ１３のボトム室からチルトシリンダ１４のボトム室に作動油が流入し、バケット８がチルトし、リフトアーム１０が下降する。このリフトアーム１０の予期しない動きは、リフトシリンダ１３とチルトシリンダ１４の保持圧が同じになるか、チルトストッパ１０ｂが作動する、すなわちチルトストッパ作動状態になることで停止する。
一方、第３実施形態においては、連通弁４２，４３内にチェック弁４２ａ，４３ａを備えているので、ボトム室連通／遮断弁４２、およびロッド室連通／遮断弁４３が第２位置である連通位置で固着しても、リフトシリンダ１３、チルトシリンダ１４のボトム室から作動油が流出することがないため、上記第１、第２実施形態のような事態は起こらない。さらに、ボトム室連通／遮断弁４２、ロッド室連通／遮断弁４３が第２位置の固着によりリフトアーム下げ動作が不能になるため、不具合の発生を運転者などが速やかに知ることができる。 (Effects peculiar to the third embodiment)
FIG. 13 is a diagram for explaining effects peculiar to the third embodiment.
When the first communication / shutoff valve 17 is fixed at the communication position, which is the second position, in the first and second embodiments, as shown in FIG. 13, between the bottom chambers of the lift cylinder 13 and the tilt cylinder 14, the rod chamber The space is always in communication. Furthermore, when the holding pressure of the lift cylinder 13 is higher than the holding pressure of the tilt cylinder 14 in a state where the tilt stopper is not operated, the hydraulic oil flows from the bottom chamber of the lift cylinder 13 into the bottom chamber of the tilt cylinder 14 and the bucket 8 tilts. Then, the lift arm 10 is lowered. The unexpected movement of the lift arm 10 is stopped when the holding pressures of the lift cylinder 13 and the tilt cylinder 14 are the same or when the tilt stopper 10b is activated, that is, the tilt stopper is activated.
On the other hand, in the third embodiment, since the check valves 42a and 43a are provided in the communication valves 42 and 43, the bottom chamber communication / shutoff valve 42 and the rod chamber communication / shutoff valve 43 are in the second position. Even if it is fixed at the position, since the hydraulic oil does not flow out from the bottom chambers of the lift cylinder 13 and the tilt cylinder 14, the situation as in the first and second embodiments does not occur. Furthermore, since the bottom arm communication / shutoff valve 42 and the rod chamber communication / shutoff valve 43 cannot be lifted by the lift arm when the second position is fixed, the driver or the like can quickly know the occurrence of the malfunction.

Claims

When lifting the attachment mounted on the end of the lift arm, a link mechanism Before moving parallel to the ground reference plane of the attachment,
A lift cylinder for elevating the attachment by the pressure oil to the lift cylinder bottom chamber and the lift cylinder rod chamber supplied through said lift arm,
A tilt cylinder that tilts the attachment when pressure oil is supplied to the tilt cylinder bottom chamber and the tilt cylinder rod chamber ;
A load handling device in a wheel loader comprising: a hydraulic pump that supplies pressure oil to each of the lift cylinder and the tilt cylinder ;
A lift arm operation detector that detects an operation of raising the lift arm;
A tilt stopper operating state detector that detects that the attachment is in a tilt stopper operating state in contact with a stopper provided on the lift arm ;
Said in communication with each other and a tilt cylinder bottom chamber side oil passage with the lift cylinder bottom chamber connected to Ru lift cylinder bottom chamber side oil passage wherein Ru is connected to the tilt cylinder bottom chamber, to the lift cylinder bottom chamber from the hydraulic pump a communicating position to supply a portion of the supplied pressure oil to the tilt cylinder bottom chamber, the lift cylinder bottom chamber side oil path and the tilt cylinder bottom chamber side oil passage and a switching is switched to a blocking position for blocking one another A valve,
Said rising operation of the lift arm by the lift arm operation detecting unit is detected, and the control unit for switching the switching valve and the tilt stopper operating condition is discovered by the tilt stopper operating state detecting unit to the communicating position, the A cargo handling device for a wheel loader, comprising:

In the wheel loader cargo handling device according to claim 1,
Comprising an attachment operation detection unit that detects an operation of tilting or dumping the previous SL attachment,
The switching valve is an electromagnetic switching valve;
Wherein the control unit, wherein the tilt stopper operating state by the tilt stopper operating state detecting section is detected, and the rise operation of the lift arm by the lift arm operation detecting unit is detected, and the by the attachment operation detection unit when tilting or dumping operation of the attachment is not detected, the cargo apparatus of a wheel loader that said switching the switching valve to the communicating position.

In the wheel loader cargo handling device according to claim 2,
Between a lift cylinder supply / discharge oil passage for supplying pressure oil to the lift cylinder bottom chamber and the lift cylinder rod chamber, and a tilt cylinder supply / discharge oil passage for supplying pressure oil to the tilt cylinder bottom chamber and the tilt cylinder rod chamber in the arranged switching valve in series, the lift cylinder and the bottom chamber side oil passage and the second communicating position where the communicating each other and the tilt cylinder bottom chamber side oil passage, the said lift cylinder bottom chamber side oil passage tilt comprising a conversion Erareru cut and a second cut-off position the second switching valve for blocking the cylinder bottom chamber side oil passage with each other,
The second switching valve is moved to the second communication position when a condition that an operation for raising the lift arm is performed and an operation for tilting or dumping the attachment is not performed is established. A wheel loader loading / unloading device that switches to the second blocking position when the condition is not satisfied.

In the wheel loader cargo handling device according to claim 3,
When an operation for tilting or dumping the attachment is detected, it is further switched to a tilt / dump operation detection position, and when the operation is not detected, a hydraulic pilot-type third switching valve is further switched to the tilt / dump non-operation detection position. And
When the third switching valve is switched to the tilt / dump non-operation detection position, the lift arm operation pressure generated by the operation to raise the lift arm, the second switching valve is cut to the second communication position instead, the the third switching valve is switched to the tilt / dump operation detection position, even if the lift arm operation pressure is generated the second switching valve, characterized in that it is held in the second blocking position The wheel loader handling device.

The wheel loader cargo handling device according to claim 1,
The switching valve is a fourth switching valve of the hydraulic pilot type,
Said in communication with each other and a tilt cylinder rod chamber side oil passage with the lift cylinder Lift cylinder rod chamber side oil passage that will be connected to the rod chamber wherein Ru is connected to the tilt cylinder rod chamber, the lift cylinder rod chamber and the tilt cylinder rod Hydraulic pressure switched to a fifth communication position for returning the pressure oil discharged from each of the chambers to the tank and a fifth shut-off position that shuts off the lift cylinder rod chamber side oil passage and the tilt cylinder rod chamber side oil passage. A pilot-type fifth switching valve;
An electromagnetic selection valve that switches to one of a lift arm raising operation pressure selection position for selecting a lift arm raising operation pressure generated by an operation for raising the lift arm, and a tank pressure selection position for selecting a tank pressure ; Further comprising
Wherein, the when the tilt stopper operating state by the tilt stopper operating state detecting section is discovered, switching the selection valve to the lift arm raising operation pressure selection position, the tilt stopper by the tilt stopper operating state detector When the operating state is not detected, switching the selection valve to the tank pressure selection position,
When the selection valve is switched to the lift arm raising operation pressure selection position by the control unit , the fourth switching valve is moved to the communication position by the lift arm operation pressure generated by the operation of raising the lift arm. the fifth switching valve the fifth communication position, the cargo apparatus of the wheel loader, characterized in that to replace each switching.

In the wheel loader cargo handling device according to claim 5,
A hydraulic pilot-type third switching valve that switches to a tilt / dump operation detection position when an operation for tilting or dumping the attachment is detected, and switches to a tilt / dump non-operation detection position when the operation is not detected;
The fourth switching valve has a bottom chamber oil passage that connects the lift cylinder bottom chamber to a hydraulic pressure source at the shut-off position, and pressurizes the lift cylinder bottom chamber and the tilt cylinder bottom chamber at the communication position. It has a bottom chamber side lift / tilt communication oil passage connected to the oil source,
The fifth switching valve has a rod chamber oil passage that connects the lift cylinder rod chamber to a hydraulic pressure source at the fifth cutoff position, and the lift cylinder rod chamber and the tilt cylinder at the fifth communication position. It has a rod chamber side lift / tilt communication oil passage that connects the rod chamber to the tank ,
The fourth switching valve and the fifth switching valve are respectively the pressure selected by the selection valve, and the third switching valve is the tilt / dump operation detection position or the tilt / dump non-operation detection position. When the pressure selected by the selection valve is higher than the output pressure of the third switching valve , the fourth switching valve is in the communication position. The wheel loader loading / unloading device , wherein the fifth switching valve is switched to the fifth communication position .

In the wheel loader cargo handling device according to claim 6,
The bottom chamber side lift / tilt communication oil passage has a bottom chamber check valve for blocking outflow of pressure oil from the lift cylinder bottom chamber ,
The rod chamber side lift / tilt communication oil passage has a rod chamber check valve that prevents the pressure oil in the tilt cylinder rod chamber from flowing back to the lift cylinder rod chamber.

In the wheel loader cargo handling device according to claim 1,
The wheel loader cargo handling device, wherein the tilt stopper operating state detection unit detects a tilt angle of the attachment based on a positional relationship between two predetermined positions in the link mechanism.

In the wheel loader cargo handling device according to claim 1,
The tilt stopper operating state detecting unit, cargo apparatus of the wheel loader, characterized in that for detecting the tilt angle of the attachment by the positional relationship between the a predetermined location in the link mechanism attachment.

In the wheel loader cargo handling device according to claim 1,
The wheel loader cargo handling device, wherein the tilt stopper operating state detection unit detects a tilt angle of the attachment based on operations of the lift cylinder and the tilt cylinder.