JPH0657786A - Structure of hydraulic circuit for backhoe equipment - Google Patents
Structure of hydraulic circuit for backhoe equipmentInfo
- Publication number
- JPH0657786A JPH0657786A JP4211049A JP21104992A JPH0657786A JP H0657786 A JPH0657786 A JP H0657786A JP 4211049 A JP4211049 A JP 4211049A JP 21104992 A JP21104992 A JP 21104992A JP H0657786 A JPH0657786 A JP H0657786A
- Authority
- JP
- Japan
- Prior art keywords
- control valve
- pilot
- oil
- hydraulic cylinder
- 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.)
- Granted
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
- E02F9/2292—Systems with two or more 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
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/26—Locking mechanisms
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2221—Control of flow rate; Load sensing arrangements
- E02F9/2239—Control of flow rate; Load sensing arrangements using two or more pumps with cross-assistance
-
- 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
- F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
- F15B20/005—Leakage; Spillage; Hose burst
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Fluid Mechanics (AREA)
- Physics & Mathematics (AREA)
- Structural Engineering (AREA)
- Civil Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Operation Control Of Excavators (AREA)
- Component Parts Of Construction Machinery (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はバックホウの旋回台の前
部、ホイルローダや農用トラクタの後部等に装備される
掘削作業用のバックホウ装置において、ブーム系の油圧
回路構造に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit structure of a boom system in a backhoe device for excavation work which is mounted on a front part of a swivel base of a backhoe, a rear part of a wheel loader or an agricultural tractor.
【０００２】[0002]
【従来の技術】バックホウにおいてバックホウ装置の油
圧回路構造の一例が、実開平２−１３９９４８号公報に
開示されている。この構造では前記公報の第４図に示す
ように、ブームの上下駆動用の油圧シリンダ（前記公報
の第４図中の１６）と第１ポンプ（前記公報の第４図中
の９）とを、上昇位置、中立位置及び下降位置の３位置
切換式の制御弁（前記公報の第４図中の１７）を介して
接続している。そして、油圧シリンダにおける上昇駆動
側の油室（前記公報の第４図中の１６ａ）と制御弁とを
接続する上昇駆動側油路（前記公報の第４図中の３６）
において、この上昇駆動側油路と第２ポンプ（前記公報
の第４図中の１０）とを、上昇位置及び中立位置を備え
た副制御弁（前記公報の第４図中の３８）を介して接続
して、第１及び第２ポンプの作動油を制御弁及び副制御
弁を介して合流させ、油圧シリンダの上昇駆動側の油室
に供給するように構成している。このように２個のポン
プからの作動油を合流させて、油圧シリンダの上昇駆動
側の油室に供給することにより、バックホウ装置のブー
ムを強い力で上昇駆動できるようにして、バックホウ装
置の掘削力を高めている。2. Description of the Related Art In a backhoe, an example of a hydraulic circuit structure of a backhoe device is disclosed in Japanese Utility Model Laid-Open No. 2-139948. In this structure, as shown in FIG. 4 of the publication, a hydraulic cylinder for vertically moving the boom (16 in FIG. 4 of the publication) and a first pump (9 in FIG. 4 of the publication) are provided. , A three-position switching type control valve (17 in FIG. 4 of the above publication) for raising, neutral, and descending positions. Then, an ascending drive oil passage (36 in FIG. 4 of the publication) that connects the oil chamber (16a in FIG. 4 of the publication) of the hydraulic cylinder to the control valve.
In the ascending drive side oil passage and the second pump (10 in FIG. 4 of the publication) via a sub-control valve (38 in FIG. 4 of the publication) having an ascending position and a neutral position. The hydraulic oils of the first and second pumps are joined together via the control valve and the sub-control valve, and are supplied to the oil chamber on the ascending drive side of the hydraulic cylinder. In this way, the hydraulic oils from the two pumps are merged and supplied to the oil chamber on the ascending drive side of the hydraulic cylinder, so that the boom of the backhoe device can be ascended and driven by a strong force, and the backhoe device is excavated. I am increasing my strength.
【０００３】[0003]
【発明が解決しようとする課題】前述のようなバックホ
ウ装置においては、ブームやアームの先端にフックを固
定して、このフックにより吊り作業を行う場合がある。
この吊り作業において、運搬物を吊り下げた状態でブー
ムを固定するには、ブーム用の制御弁及び副制御弁を中
立位置に操作しておけばよいのであるが、この制御弁の
ような３位置切換式ではどうしても作動油の漏れが生じ
るので、制御弁及び副制御弁を中立位置に操作しても、
作動油の漏れにより吊り下げ状態のブームが次第に下降
してくる場合がある。In the backhoe device as described above, the hook may be fixed to the tip of the boom or the arm and the hanging operation may be performed by the hook.
In this hoisting work, in order to fix the boom with the goods being hung, the boom control valve and the sub control valve may be operated to the neutral position. With the position switching type, hydraulic oil will inevitably leak, so even if the control valve and sub control valve are operated to the neutral position,
The suspended boom may descend gradually due to hydraulic fluid leakage.
【０００４】そこで、図５に示すように制御弁２１及び
副制御弁２５からブーム用の油圧シリンダ１１への油路
５１，５６の各々に、一対のパイロットチェック弁５７
を設けることが考えられる。このパイロットチェック弁
５７は、油圧シリンダ１１の上昇駆動側の油室１１Ｕへ
の作動油の流れを許し、逆に制御弁２１及び副制御弁２
５への作動油の流れを止めるものであり、この一対のパ
イロットチェック弁５７により、吊り下げ状態でのブー
ムの下降を防止することができる。そして、制御弁２１
の下降位置への操作に連動してパイロット油路５８から
のパイロット圧により、一対のパイロットチェック弁５
７が開操作される。しかしながら、図５に示す構造では
パイロットチェック弁５７が一対備えられているので、
構造の簡素化の面で改良の余地がある。本発明は、制御
弁及び副制御弁を中立位置に操作している状態でのブー
ムの下降を防止する構造を、簡素に構成することを目的
としている。Therefore, as shown in FIG. 5, a pair of pilot check valves 57 are provided in each of the oil passages 51 and 56 from the control valve 21 and the sub-control valve 25 to the boom hydraulic cylinder 11.
It is possible to provide. This pilot check valve 57 allows the flow of hydraulic oil to the oil chamber 11U on the ascending drive side of the hydraulic cylinder 11, and conversely, the control valve 21 and the sub control valve 2
The flow of the hydraulic oil to the valve 5 is stopped, and the pair of pilot check valves 57 can prevent the boom from descending in the suspended state. And the control valve 21
The pilot pressure from the pilot oil passage 58 is interlocked with the operation of the pair of pilot check valves 5
7 is opened. However, in the structure shown in FIG. 5, since a pair of pilot check valves 57 are provided,
There is room for improvement in terms of structural simplification. It is an object of the present invention to simply configure a structure that prevents the boom from descending when the control valve and the sub control valve are operated to the neutral position.
【０００５】[0005]
【課題を解決するための手段】本発明の特徴は以上のよ
うなバックホウ装置の油圧回路構造において、次のよう
に構成することにある。つまり、ブームの上下駆動用の
油圧シリンダと第１ポンプとを、上昇位置、中立位置及
び下降位置の３位置切換式の制御弁を介して接続し、油
圧シリンダにおける上昇駆動側の油室と制御弁とを接続
する上昇駆動側油路において、この上昇駆動側油路と第
２ポンプとを、上昇位置及び中立位置を備えた副制御弁
を介して接続して、第１及び第２ポンプの作動油を制御
弁及び副制御弁を介して合流させて、油圧シリンダの上
昇駆動側の油室に供給するように構成すると共に、上昇
駆動側油路と副制御弁側の油路との接続点よりも油圧シ
リンダ側の上昇駆動側油路部分に、接続点から上昇駆動
側の油室への作動油の流れを許し、逆に上昇駆動側の油
室から接続点への作動油の流れを止めるパイロットチェ
ック弁を備え、制御弁の下降位置への操作に連動して、
パイロットチェック弁を開操作するパイロット操作手段
を備えてある。A feature of the present invention is that the hydraulic circuit structure of the backhoe device as described above is configured as follows. That is, the hydraulic cylinder for vertically driving the boom and the first pump are connected via a three-position switching type control valve of the ascending position, the neutral position, and the descending position, and control is performed with the oil chamber on the ascending drive side of the hydraulic cylinder. In the ascending drive side oil passage connecting the valve, the ascending drive side oil passage and the second pump are connected via a sub control valve having an ascending position and a neutral position, and the first and second pumps are connected. The hydraulic oil is merged through the control valve and the sub-control valve to be supplied to the oil chamber on the ascending drive side of the hydraulic cylinder, and the oil path on the ascending drive side and the oil path on the sub-control valve side are connected. Allow the flow of hydraulic oil from the connection point to the oil chamber on the ascending drive side in the oil passage portion on the ascending drive side of the hydraulic cylinder side from the point Equipped with a pilot check valve to stop the In conjunction with each other,
Pilot operating means for opening the pilot check valve is provided.
【０００６】[0006]
【作用】本発明のように構成すると例えば図１に示すよ
うに、ブームの上昇操作時には第１及び第２ポンプ８，
１５からの作動油が、制御弁２１及び副制御弁２５から
接続点Ａで合流してパイロットチェック弁５２を通り、
油圧シリンダ１１の上昇駆動側の油室１１Ｕに供給され
る。これにより、油圧シリンダ１１が上昇側に作動して
ブーム４が上昇駆動される。逆にブームの下降操作時に
は制御弁２１のみから、又は制御弁２１及び副制御２５
から、油圧シリンダ１１の下降駆動側の油室１１Ｄに作
動油が供給される。この場合、パイロット操作手段によ
りパイロットチェック弁５２が開操作されるので、油圧
シリンダ１１の上昇駆動側の油室１１Ｕ内の作動油が、
パイロットチェック弁５２を通って支障なく排出され
る。これにより、油圧シリンダ１１が下降側に作動して
ブームが下降駆動される。With the construction of the present invention, as shown in FIG. 1, for example, the first and second pumps 8, 8
The hydraulic fluid from 15 merges from the control valve 21 and the auxiliary control valve 25 at the connection point A, passes through the pilot check valve 52,
The oil is supplied to the oil chamber 11U on the ascending drive side of the hydraulic cylinder 11. As a result, the hydraulic cylinder 11 is actuated to the up side, and the boom 4 is driven up. On the contrary, during the boom lowering operation, only the control valve 21 or the control valve 21 and the sub-control 25
From this, the hydraulic oil is supplied to the oil chamber 11D on the descending drive side of the hydraulic cylinder 11. In this case, since the pilot check valve 52 is opened by the pilot operating means, the hydraulic oil in the oil chamber 11U on the ascending drive side of the hydraulic cylinder 11 is
It is discharged without trouble through the pilot check valve 52. As a result, the hydraulic cylinder 11 is operated downward and the boom is driven downward.
【０００７】ブームを所望の位置で固定するために、制
御弁２１及び副制御弁２５を中立位置に操作したとす
る。この状態において、バックホウ装置自身の重量やバ
ックホウ装置に吊り下げられている運搬物の重量等によ
りブームが下降しようとして、油圧シリンダ１１の上昇
駆動側の油室１１Ｕから作動油が排出されようとした場
合、接続点Ａよりも油室１１Ｕ側にパイロットチェック
弁５２があるので、油室１１Ｕからの作動油は先ずパイ
ロットチェック弁５２に供給される。この場合、パイロ
ットチェック弁５２は閉位置にあるので、油室１１Ｕか
らの作動油はパイロットチェック弁５２を通ることがで
きず、ブームの下降が阻止されてブームがその位置に保
持される。It is assumed that the control valve 21 and the auxiliary control valve 25 are operated to the neutral position in order to fix the boom at a desired position. In this state, the boom is going to descend due to the weight of the backhoe device itself, the weight of the object suspended in the backhoe device, and the like, and the hydraulic oil is about to be discharged from the oil chamber 11U on the ascending drive side of the hydraulic cylinder 11. In this case, since the pilot check valve 52 is located closer to the oil chamber 11U than the connection point A, the hydraulic oil from the oil chamber 11U is first supplied to the pilot check valve 52. In this case, since the pilot check valve 52 is in the closed position, the hydraulic oil from the oil chamber 11U cannot pass through the pilot check valve 52, the descent of the boom is blocked, and the boom is held in that position.
【０００８】そして、図５に示すように接続点Ａよりも
制御弁２１及び副制御弁２５側に、パイロットチェック
弁５７を設けると、制御弁２１及び副制御弁２５の各々
にパイロットチェック弁５７が必要となり、２個のパイ
ロットチェック弁５７が必要になる。これに対して、本
発明では図１に示すように、接続点Ａよりも油圧シリン
ダ１１の油室１１Ｕ側にパイロットチェック弁５２があ
るので、この１個のパイロットチェック弁５２でよく、
２個のパイロットチェック弁５２は必要ない。As shown in FIG. 5, when a pilot check valve 57 is provided closer to the control valve 21 and the sub control valve 25 than the connection point A, the pilot check valve 57 is provided for each of the control valve 21 and the sub control valve 25. Is required, and two pilot check valves 57 are required. On the other hand, in the present invention, as shown in FIG. 1, since there is the pilot check valve 52 on the oil chamber 11U side of the hydraulic cylinder 11 with respect to the connection point A, this one pilot check valve 52 is sufficient.
Two pilot check valves 52 are not needed.
【０００９】[0009]
【発明の効果】以上のように、ブーム用として制御弁と
副制御弁を装備したバックホウ装置において、パイロッ
トチェック弁を装備することによりブームの下降を防止
することができるようになって、吊り作業等の作業性を
向上させることができた。又、ブーム用として制御弁と
副制御弁の２個装備していても、１個のパイロットチェ
ック弁でよいので、生産コストの面でも有利な構造とな
る。As described above, in the backhoe device equipped with the control valve and the sub-control valve for the boom, by installing the pilot check valve, it becomes possible to prevent the boom from descending, and the lifting work is performed. It was possible to improve workability. Further, even if two control valves and sub-control valves are provided for the boom, only one pilot check valve is required, which is advantageous in terms of production cost.
【００１０】[0010]
【実施例】以下、本発明の実施例を図面に基づいて説明
する。図４はバックホウの全体側面を示しており、ゴム
クローラ形式の走行装置１に旋回台２が支持され、旋回
台２の前部にバックホウ装置３が備えられている。バッ
クホウ装置３は、油圧シリンダ１１により上下に揺動駆
動されるブーム４、油圧シリンダ１２により前後に揺動
駆動されるアーム５、及び油圧シリンダ１３により掻き
込み揺動駆動されるバケット６を備えて構成されてい
る。そして、バックホウ装置３の全体が旋回台２の前部
の縦軸芯Ｐ１周りに、油圧シリンダ７により揺動駆動自
在に支持されている。Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows the entire side surface of the backhoe, in which a swivel base 2 is supported by a traveling device 1 of a rubber crawler type, and a backhoe device 3 is provided in front of the swivel base 2. The backhoe device 3 is provided with a boom 4 which is rocked up and down by a hydraulic cylinder 11, an arm 5 which is rocked back and forth by a hydraulic cylinder 12, and a bucket 6 which is rocked and rocked by a hydraulic cylinder 13. It is configured. The entire backhoe device 3 is swingably driven by a hydraulic cylinder 7 around a vertical axis P1 in the front part of the swivel base 2.
【００１１】次に、このバックホウの油圧回路構造につ
いて説明する。図１に示すように、第１ポンプ８に対し
て右の走行装置１の油圧モータ１４用の制御弁２６、ブ
ーム４の油圧シリンダ１１用の制御弁２１、及びバケッ
ト６の油圧シリンダ１３用の制御弁２３が並列的に接続
されている。第２ポンプ１５に対して左の走行装置１の
油圧モータ１６用の制御弁２８、ブーム４の油圧シリン
ダ１１用の副制御弁２５、及びアーム５の油圧シリンダ
１２用の制御弁２２、及びサービスポート（図示せず）
用の制御弁２９が並列的に接続されている。第３ポンプ
１７に対して旋回台２の油圧モータ１８用の制御弁２
４、図４に示すドーザ４５を昇降操作する油圧シリンダ
１９用の制御弁４６、及びバックホウ装置３の揺動操作
を行う油圧シリンダ７用の制御弁２７が並列的に接続さ
れている。Next, the hydraulic circuit structure of the backhoe will be described. As shown in FIG. 1, the control valve 26 for the hydraulic motor 14 of the traveling device 1 on the right side of the first pump 8, the control valve 21 for the hydraulic cylinder 11 of the boom 4, and the hydraulic cylinder 13 of the bucket 6 are provided. The control valve 23 is connected in parallel. The control valve 28 for the hydraulic motor 16 of the traveling device 1 on the left side of the second pump 15, the auxiliary control valve 25 for the hydraulic cylinder 11 of the boom 4, the control valve 22 for the hydraulic cylinder 12 of the arm 5, and the service. Port (not shown)
The control valve 29 for is connected in parallel. Control valve 2 for hydraulic motor 18 of swivel 2 with respect to third pump 17
4, a control valve 46 for the hydraulic cylinder 19 for vertically moving the dozer 45 shown in FIG. 4, and a control valve 27 for the hydraulic cylinder 7 for rocking the backhoe device 3 are connected in parallel.
【００１２】制御弁２１，２２，２３，２４，２６，２
７，２８，２９，４６及び副制御弁２５はセンターバイ
パス型式であり、走行装置１用の制御弁２６，２８、サ
ービスポート用の制御弁２９、及びドーザ４５用の制御
弁４６が、操作レバー（図示せず）により操作される機
械操作式で中立復帰型である。そして、ブーム４用の制
御弁２１及び副制御弁２５、アーム５用の制御弁２２、
バケット６用の制御弁２３、旋回台２用の制御弁２４、
及びバックホウ装置３揺動用の制御弁２７が油圧による
パイロット操作式で中立復帰型である。Control valves 21, 22, 23, 24, 26, 2
7, 28, 29, 46 and the auxiliary control valve 25 are of the center bypass type, and the control valves 26, 28 for the traveling device 1, the control valve 29 for the service port, and the control valve 46 for the dozer 45 are the operating levers. It is a mechanically operated and neutral return type operated by (not shown). Then, the control valve 21 and the sub control valve 25 for the boom 4, the control valve 22 for the arm 5,
A control valve 23 for the bucket 6, a control valve 24 for the swivel base 2,
Further, the control valve 27 for swinging the backhoe device 3 is a pilot operated type by hydraulic pressure and is of a neutral return type.
【００１３】次に、バックホウ装置３用の制御弁２１，
２２，２３，２７、副制御弁２５及び旋回台２用の制御
弁２４の操作系の構造について説明する。図２及び図４
に示すように、旋回台２の運転部２０に前後左右に操作
自在な右操作レバー９及び左操作レバー１０が備えられ
ている。そして、右操作レバー９に対してその前後操作
により、パイロット圧を発生する一対のパイロット弁４
１ａ，４１ｂ、及び左右操作によりパイロット圧を発生
するパイロット弁４２ａ，４２ｂが備えられている。左
操作レバー１０に対してその前後操作により、パイロッ
ト圧を発生するパイロット弁４３ａ，４３ｂ、及び左右
操作によりパイロット圧を発生するパイロット弁４４
ａ，４４ｂが備えられており、各パイロット弁４１ａ〜
４４ｂにパイロット圧を供給するパイロットポンプ３０
が備えられている。Next, the control valve 21 for the backhoe device 3,
The structure of the operation system of 22, 23, 27, the sub control valve 25, and the control valve 24 for the swivel base 2 will be described. 2 and 4
As shown in FIG. 3, the operating unit 20 of the swivel base 2 is provided with a right operation lever 9 and a left operation lever 10 that can be operated in the front, rear, left and right directions. The pair of pilot valves 4 that generate pilot pressure by operating the right operation lever 9 back and forth.
1a, 41b and pilot valves 42a, 42b for generating pilot pressure by left and right operation are provided. Pilot valves 43a and 43b that generate pilot pressure by operating the left operation lever 10 forward and backward, and pilot valve 44 that generates pilot pressure by operating left and right.
a, 44b are provided, and each pilot valve 41a-
Pilot pump 30 for supplying pilot pressure to 44b
Is provided.
【００１４】図２に示すように、右操作レバー９のパイ
ロット弁４１ａ，４１ｂからのパイロット油路３１ａ，
３１ｂが、ブーム４用の制御弁２１及び副制御弁２５に
接続され、右操作レバー９のパイロット弁４２ａ，４２
ｂからのパイロット油路３２ａ，３２ｂが、バケット６
用の制御弁２３に接続されている。これにより、右操作
レバー９を前後に操作すると、パイロット弁４１ａ，４
１ｂからのパイロット圧により制御弁２１及び副制御弁
２５が操作されて、ブーム４が上下に揺動駆動され（後
述するように、副制御弁２５はブーム４の上昇操作時に
のみ作動）、右操作レバー９を左右に操作すると、パイ
ロット弁４２ａ，４２ｂからのパイロット圧により制御
弁２３が操作されて、バケット６が前後に揺動駆動され
る。As shown in FIG. 2, the pilot oil passages 31a from the pilot valves 41a and 41b of the right operating lever 9 are
31 b is connected to the control valve 21 and the sub control valve 25 for the boom 4, and the pilot valves 42 a, 42 of the right operation lever 9 are connected.
the pilot oil passages 32a and 32b from the
Is connected to the control valve 23 for. As a result, when the right operation lever 9 is operated back and forth, the pilot valves 41a, 4a
The control valve 21 and the sub-control valve 25 are operated by the pilot pressure from 1b, and the boom 4 is driven to swing up and down (the sub-control valve 25 operates only when the boom 4 is lifted, as will be described later). When the operating lever 9 is operated to the left or right, the control valve 23 is operated by the pilot pressure from the pilot valves 42a and 42b, and the bucket 6 is rocked back and forth.
【００１５】左操作レバー１０のパイロット弁４３ａ，
４３ｂからのパイロット油路３３ａ，３３ｂが、アーム
５用の制御弁２２に接続され、パイロット弁４４ａ，４
４ｂからのパイロット油路３４ａ，３４ｂが、切換弁３
６が接続されている。切換弁３６に対して、旋回台２用
の制御弁２４とバックホウ装置３揺動用の制御弁２７が
接続されている。The pilot valve 43a of the left operating lever 10,
Pilot oil passages 33a and 33b from 43b are connected to the control valve 22 for the arm 5, and pilot valves 44a and 4b are connected.
4b from the pilot oil passages 34a, 34b, the switching valve 3
6 is connected. A control valve 24 for the swivel base 2 and a control valve 27 for swinging the backhoe device 3 are connected to the switching valve 36.
【００１６】図２に示す状態は、切換弁３６を第１位置
３６ａに操作している状態であり、パイロット弁４４
ａ，４４ｂと旋回台２用の制御弁２４とが接続された状
態である。以上の状態で左操作レバー１０を前後に操作
すると、パイロット弁４３ａ，４３ｂからのパイロット
圧により制御弁２２が操作されて、アーム５が前後に揺
動駆動され、左操作レバー１０を左右に操作すると、パ
イロット弁４４ａ，４４ｂからのパイロット圧により制
御弁２４が操作されて、旋回台２が右及び左旋回側に駆
動される。この場合、バックホウ装置３揺動用の制御弁
２７は、切換弁３６の作用により中立位置に保持されて
いる。In the state shown in FIG. 2, the switching valve 36 is operated to the first position 36a, and the pilot valve 44
It is in a state where the a and 44b and the control valve 24 for the swivel base 2 are connected. When the left operation lever 10 is operated back and forth in the above state, the control valve 22 is operated by the pilot pressure from the pilot valves 43a and 43b, the arm 5 is rocked back and forth, and the left operation lever 10 is operated left and right. Then, the control valve 24 is operated by the pilot pressure from the pilot valves 44a and 44b, and the swivel base 2 is driven to the right and left swivel sides. In this case, the control valve 27 for swinging the backhoe device 3 is held at the neutral position by the action of the switching valve 36.
【００１７】そして、図２に示す状態において切換弁３
６を第２位置３６ｂに操作すれば、パイロット弁４４
ａ，４４ｂとバックホウ装置３揺動用の制御弁２７とが
接続された状態となる。これにより、左操作レバー１０
を左右に操作すると、パイロット弁４４ａ，４４ｂによ
り制御弁２７が操作されて、バックホウ装置３の全体が
左右に揺動操作される。この場合、旋回台２用の制御弁
２４は、切換弁３６の作用により中立位置に保持されて
いる。In the state shown in FIG. 2, the switching valve 3
6 to the second position 36b, the pilot valve 44
The a and 44b and the control valve 27 for swinging the backhoe device 3 are connected. As a result, the left operation lever 10
When the is operated to the left or right, the control valve 27 is operated by the pilot valves 44a and 44b, and the entire backhoe device 3 is rocked to the left and right. In this case, the control valve 24 for the swivel base 2 is held in the neutral position by the action of the switching valve 36.
【００１８】以上のような操作状態において、右及び左
操作レバー９，１０を中立位置から大きく操作する程、
パイロット弁４１ａ〜４４ｂに発生するパイロット圧が
大きくなるように構成されている。これにより、右及び
左操作レバー９，１０を中立位置から大きく操作する
程、パイロット弁４１ａ〜４４ｂのパイロット圧が大と
なり、制御弁２１〜２４，２７及び副制御弁２５が流量
大側に操作される。つまり、右及び左操作レバー９，１
０を大きく操作する程、油圧シリンダ１１〜１３，７及
び油圧モータ１８が高速で作動するように構成してい
る。又、図２に示すアンロード弁３７をアンロード位置
に操作すると、パイロットポンプ３０からのパイロット
圧がパイロット弁４１ａ〜４４ｂに供給されなくなる。
従って、この状態で右及び左操作レバー９，１０を操作
してもパイロット圧は発生せず、バックホウ装置３及び
旋回台２は作動しない。In the above operation state, the larger the right and left operation levers 9 and 10 are operated from the neutral position,
The pilot pressures generated in the pilot valves 41a-44b are configured to increase. As a result, as the right and left operation levers 9 and 10 are operated from the neutral position, the pilot pressure of the pilot valves 41a to 44b increases, and the control valves 21 to 24 and 27 and the auxiliary control valve 25 operate to the larger flow rate side. To be done. That is, the right and left operation levers 9, 1
The hydraulic cylinders 11 to 13, 7 and the hydraulic motor 18 are configured to operate at higher speeds as the value of 0 is increased. When the unload valve 37 shown in FIG. 2 is operated to the unload position, the pilot pressure from the pilot pump 30 is no longer supplied to the pilot valves 41a-44b.
Therefore, even if the right and left operation levers 9 and 10 are operated in this state, the pilot pressure is not generated and the backhoe device 3 and the swivel base 2 do not operate.
【００１９】図１に示すように、走行装置１用の油圧モ
ータ１４，１６は出力可変式に構成されており、この油
圧モータ１４，１６を油圧シリンダ３８により高低２段
に変速操作する。そして、パイロットポンプ３０に油圧
シリンダ３８用の切換弁３９が接続されており、この切
換弁３９を切換操作し油圧シリンダ３８を伸縮操作し
て、油圧モータ１４，１６を高低２段に変速操作する。As shown in FIG. 1, the hydraulic motors 14 and 16 for the traveling device 1 are of variable output type, and the hydraulic motors 38 and 16 are operated by a hydraulic cylinder 38 to shift between high and low stages. A switching valve 39 for the hydraulic cylinder 38 is connected to the pilot pump 30, and the switching valve 39 is switched to operate the hydraulic cylinder 38 to expand and contract to shift the hydraulic motors 14 and 16 in two high and low stages. .
【００２０】次に、ブーム４用の制御弁２１及び副制御
弁２５について説明する。図３及び図１に示すように、
制御弁２１及び副制御弁２５は上昇位置２１Ｕ，２５
Ｕ、中立位置２１Ｎ，２５Ｎ、及び下降位置２１Ｄ，２
５Ｄの３位置切換式でパイロット操作式であり、中立復
帰型である。右操作レバー９のパイロット弁４１ａから
のパイロット油路３１ａが、制御弁２１及び副制御弁２
５の上昇位置２１Ｕ，２５Ｕ側に並列的に接続されてお
り、右操作レバー９のパイロット弁４１ｂからのパイロ
ット油路３１ｂが、制御弁２１の下降位置２１Ｄ側に接
続されている。そして、副制御弁２５の下降位置２５Ｄ
側はアンロード状態となっている。Next, the control valve 21 and the auxiliary control valve 25 for the boom 4 will be described. As shown in FIGS. 3 and 1,
The control valve 21 and the sub-control valve 25 are in the raised positions 21U, 25
U, neutral positions 21N, 25N, and lowered positions 21D, 2
It is a 5D 3-position switching type, pilot operated type, and neutral return type. The pilot oil passage 31a from the pilot valve 41a of the right operation lever 9 is connected to the control valve 21 and the sub control valve 2.
5 are connected in parallel to the ascending positions 21U and 25U, and the pilot oil passage 31b from the pilot valve 41b of the right operation lever 9 is connected to the descending position 21D side of the control valve 21. Then, the descending position 25D of the sub control valve 25
The side is unloading.
【００２１】油圧シリンダ１１の下降駆動側の油室１１
Ｄ及び上昇駆動側の油室１１Ｕと制御弁２１とが、下降
駆動側油路４９及び上昇駆動側油路５０を介して接続さ
れており、副制御弁２５からの上昇駆動用の油路５１が
上昇駆動側油路５０に接続されている。Oil chamber 11 on the lowering drive side of hydraulic cylinder 11
D and the oil chamber 11U on the ascending drive side are connected to the control valve 21 via the descending drive side oil passage 49 and the ascending drive side oil passage 50, and the ascending drive oil passage 51 from the sub-control valve 25. Is connected to the ascending drive side oil passage 50.
【００２２】油路５１と上昇駆動側油路５０との接続点
Ａよりも、油圧シリンダ１１側の上昇駆動側油路５０部
分に、パイロットチェック弁５２が設けられている。こ
のパイロットチェック弁５２は、弁体５２ｄにより仕切
られる３つの油室５２ａ，５２ｂ，５２ｃで形成されて
おり、上昇駆動側油路５０が油室５２ａ，５２ｂに接続
されている。パイロットチェック弁５２の油室５２ｃと
制御弁２１とが、パイロット油路５３及びパイロットチ
ェック弁５４（パイロット操作手段に相当）を介して接
続されており、パイロットチェック弁５４を開操作する
パイロット油路５５（パイロット操作手段に相当）が、
パイロット油路３１ｂから延出されてパイロットチェッ
ク弁５４に接続されている。A pilot check valve 52 is provided in a portion of the ascending drive side oil passage 50 closer to the hydraulic cylinder 11 than the connection point A between the oil passage 51 and the ascending drive side oil passage 50. This pilot check valve 52 is formed by three oil chambers 52a, 52b, 52c partitioned by a valve body 52d, and an ascending drive side oil passage 50 is connected to the oil chambers 52a, 52b. The oil chamber 52c of the pilot check valve 52 and the control valve 21 are connected via a pilot oil passage 53 and a pilot check valve 54 (corresponding to pilot operating means), and the pilot oil passage for opening the pilot check valve 54 is connected. 55 (corresponding to pilot operating means)
It extends from the pilot oil passage 31b and is connected to the pilot check valve 54.
【００２３】以上の構造により、右操作レバー９をブー
ム４の上昇側に操作してパイロット弁４１ａからパイロ
ット圧が発生すると、制御弁２１及び副制御弁２５の両
方が上昇位置２１Ｕ，２５Ｕに操作される。これによ
り、第１及び第２ポンプ８，１５からの作動油が、制御
弁２１及び副制御弁２５から接続点Ａで合流して、パイ
ロットチェック弁５２の油室５２ａに供給される。この
場合、パイロットチェック弁５４は閉位置にある。従っ
て、油室５２ａ内の作動油圧で弁体５２ｄが紙面上方に
押されて、油室５２ｃ内の油が絞り油路５２ｅを通り油
室５２ａに入り込み、弁体５２ｄが紙面上方に移動し
て、油室５２ａと油室５２ｂが連通する。これにより、
合流した作動油が油圧シリンダ１１の上昇駆動側の油室
１１Ｕに供給されて、油圧シリンダ１１が伸長してブー
ム４が上昇駆動される。With the above structure, when the right operation lever 9 is operated to the rising side of the boom 4 to generate the pilot pressure from the pilot valve 41a, both the control valve 21 and the sub control valve 25 are operated to the raised positions 21U and 25U. To be done. As a result, the hydraulic oil from the first and second pumps 8 and 15 merges from the control valve 21 and the sub control valve 25 at the connection point A, and is supplied to the oil chamber 52a of the pilot check valve 52. In this case, the pilot check valve 54 is in the closed position. Therefore, the valve body 52d is pushed upward in the drawing by the operating hydraulic pressure in the oil chamber 52a, the oil in the oil chamber 52c passes through the throttle oil passage 52e and enters the oil chamber 52a, and the valve 52d moves upward in the drawing. The oil chamber 52a and the oil chamber 52b communicate with each other. This allows
The combined hydraulic oils are supplied to the oil chamber 11U on the ascending drive side of the hydraulic cylinder 11, the hydraulic cylinder 11 extends and the boom 4 is driven to ascend.
【００２４】右操作レバー９をブーム４の下降側に操作
してパイロット弁４１ｂからパイロット圧が発生する
と、制御弁２１のみが下降位置２１Ｄに操作されて、副
制御弁２５は中立位置２５Ｎに保持される。これによ
り、第１ポンプ８からの作動油が油圧シリンダ１１の下
降駆動側の油室１１Ｄに供給され、上昇駆動側の油室１
１Ｕ内の作動油がパイロットチェック弁５２の油室５２
ｂに供給される。この場合、パイロット油路３１ｂのパ
イロット圧が、パイロット油路５５を介してパイロット
チェック弁５４に供給されて、このパイロットチェック
弁５４が開操作される。従って、油室５２ｂ内の作動油
圧で弁体５２ｄが紙面上方に押されて、油室５２ａと油
室５２ｂが連通する。これにより、上昇駆動側の油室１
１Ｕ内の作動油が制御弁２１に戻り、油圧シリンダ１１
が収縮してブーム４が下降駆動される。When the right operating lever 9 is operated to the down side of the boom 4 and pilot pressure is generated from the pilot valve 41b, only the control valve 21 is operated to the down position 21D, and the auxiliary control valve 25 is held at the neutral position 25N. To be done. As a result, the hydraulic oil from the first pump 8 is supplied to the oil chamber 11D on the descending drive side of the hydraulic cylinder 11, and the oil chamber 1 on the ascending drive side.
The hydraulic oil in 1U is the oil chamber 52 of the pilot check valve 52.
b. In this case, the pilot pressure in the pilot oil passage 31b is supplied to the pilot check valve 54 via the pilot oil passage 55, and the pilot check valve 54 is opened. Therefore, the valve body 52d is pushed upward by the working oil pressure in the oil chamber 52b, so that the oil chamber 52a and the oil chamber 52b communicate with each other. Thereby, the oil chamber 1 on the ascending drive side
The hydraulic oil in 1U returns to the control valve 21, and the hydraulic cylinder 11
Contracts and the boom 4 is driven downward.
【００２５】右操作レバー９を中立位置に操作している
と、図３に示すように制御弁２１及び副制御弁２５の両
方が中立位置２１Ｎ，２５Ｎに操作される。制御弁２１
及び副制御弁２５の中立位置２１Ｎ，２５Ｎにおいて、
パイロット油路５５にパイロット圧は発生せず、パイロ
ット油路５３が制御弁２１の中立位置２１Ｎで遮断され
ているので、パイロットチェック弁５４は閉位置にあ
る。従って、油圧シリンダ１１の上昇駆動側の油室１１
Ｕからの作動油が、パイロットチェック弁５２の油室５
２ｂに入り込んでも、弁体５２ｄが図１に示す位置から
紙面上方に移動するようなことはなく、この弁体５２ｄ
により油室５２ａと油室５２ｂとが遮断された状態が維
持される。これにより、ブーム４が下降することはな
い。When the right operating lever 9 is operated to the neutral position, both the control valve 21 and the auxiliary control valve 25 are operated to the neutral positions 21N and 25N as shown in FIG. Control valve 21
And at the neutral positions 21N and 25N of the sub control valve 25,
Since no pilot pressure is generated in the pilot oil passage 55 and the pilot oil passage 53 is shut off at the neutral position 21N of the control valve 21, the pilot check valve 54 is in the closed position. Therefore, the oil chamber 11 on the ascending drive side of the hydraulic cylinder 11
The hydraulic oil from U is the oil chamber 5 of the pilot check valve 52.
Even if the valve body 52d enters the 2b, the valve body 52d does not move upward from the position shown in FIG.
As a result, the state where the oil chamber 52a and the oil chamber 52b are shut off is maintained. As a result, the boom 4 does not descend.
【００２６】〔別実施例〕前述の実施例では副制御弁２
５を上昇位置２５Ｕ、中立位置２５Ｎ及び下降位置２５
Ｄの３位置を備えた型式に構成しているが、この副制御
弁２５を上昇位置２５Ｕと中立位置２５Ｎの２位置を備
えた型式に構成してもよい。そして、ブーム４用の制御
弁２１及び副制御弁２５をパイロット操作式ではなく、
機械操作式や電磁操作式に構成してもよい。そして、本
発明はバックホウばかりでなく、ホイルローダの後部や
農用トラクタの後部に装備されるバックホウ装置３にも
適用できる。[Other Embodiment] In the above embodiment, the sub control valve 2 is used.
5 up position 25U, neutral position 25N and down position 25
Although the auxiliary control valve 25 is configured to have the three positions D, the auxiliary control valve 25 may be configured to have the two positions of the rising position 25U and the neutral position 25N. Then, the control valve 21 and the auxiliary control valve 25 for the boom 4 are not pilot operated but
It may be mechanically operated or electromagnetically operated. The present invention can be applied not only to the backhoe but also to the backhoe device 3 mounted on the rear portion of the wheel loader or the rear portion of the agricultural tractor.
【００２７】尚、特許請求の範囲の項に図面との対照を
便利にする為に符号を記すが、該記入により本発明は添
付図面の構成に限定されるものではない。It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.
【図１】バックホウの全体の油圧回路図1] Overall hydraulic circuit diagram of backhoe
【図２】右及び左操作レバーのパイロット圧系の油圧回
路図FIG. 2 is a hydraulic circuit diagram of pilot pressure systems for the right and left operating levers.
【図３】ブーム用の制御弁及び副制御弁、パイロットチ
ェック弁の油圧回路図FIG. 3 is a hydraulic circuit diagram of a boom control valve, a sub control valve, and a pilot check valve.
【図４】バックホウの全体側面図FIG. 4 is an overall side view of the backhoe.
【図５】本発明と比較する為に提示した比較例におけ
る、バックホウの全体の油圧回路図FIG. 5 is an overall hydraulic circuit diagram of a backhoe in a comparative example presented for comparison with the present invention.
４ ブーム ８ 第１ポンプ １１ 油圧シリンダ １１Ｕ 油圧シリンダの上昇駆動側の油室 １５ 第２ポンプ ２１ 制御弁 ２１Ｕ 制御弁の上昇位置 ２１Ｎ 制御弁の中立位置 ２１Ｄ 制御弁の下降位置 ２５ 副制御弁 ２５Ｕ 副制御弁の上昇位置 ２５Ｎ 副制御弁の中立位置 ５０ 上昇駆動側油路 ５１ 副制御弁側の油路 ５２ パイロットチェック弁 ５４，５５ パイロット操作手段 Ａ 接続点 4 boom 8 1st pump 11 hydraulic cylinder 11U hydraulic chamber on the ascending drive side of hydraulic cylinder 15 2nd pump 21 control valve 21U control valve rising position 21N control valve neutral position 21D control valve falling position 25 auxiliary control valve 25U auxiliary Raising position of control valve 25N Neutral position of sub control valve 50 Oil path for rising drive 51 Oil passage for sub control valve 52 Pilot check valve 54, 55 Pilot operation means A Connection point
Claims (1)
ダ（１１）と第１ポンプ（８）とを、上昇位置（２１
Ｕ）、中立位置（２１Ｎ）及び下降位置（２１Ｄ）の３
位置切換式の制御弁（２１）を介して接続し、前記油圧
シリンダ（１１）における上昇駆動側の油室（１１Ｕ）
と前記制御弁（２１）とを接続する上昇駆動側油路（５
０）において、この上昇駆動側油路（５０）と第２ポン
プ（１５）とを、上昇位置（２５Ｕ）及び中立位置（２
５Ｎ）を備えた副制御弁（２５）を介して接続して、前
記第１及び第２ポンプ（８），（１５）の作動油を制御
弁（２１）及び副制御弁（２５）を介して合流させて、
前記油圧シリンダ（１１）の上昇駆動側の油室（１１
Ｕ）に供給するように構成すると共に、前記上昇駆動側
油路（５０）と副制御弁（２５）側の油路（５１）との
接続点（Ａ）よりも前記油圧シリンダ（１１）側の上昇
駆動側油路（５０）部分に、前記接続点（Ａ）から上昇
駆動側の油室（１１Ｕ）への作動油の流れを許し、逆に
上昇駆動側の油室（１１Ｕ）から接続点（Ａ）への作動
油の流れを止めるパイロットチェック弁（５２）を備
え、前記制御弁（２１）の下降位置（２１Ｄ）への操作
に連動して、前記パイロットチェック弁（５２）を開操
作するパイロット操作手段（５４），（５５）を備えて
あるバックホウ装置の油圧回路構造。1. A hydraulic cylinder (11) for vertically driving a boom (4) and a first pump (8) are provided at a raised position (21).
U), neutral position (21N) and descending position (21D) 3
An oil chamber (11U) on the ascending drive side of the hydraulic cylinder (11), which is connected via a position switching type control valve (21).
And the ascending drive side oil passage (5
0), the ascending drive side oil passage (50) and the second pump (15) are connected to the ascending position (25U) and the neutral position (2U).
5N) is connected via a sub-control valve (25), and the operating oil of the first and second pumps (8) and (15) is passed through the control valve (21) and the sub-control valve (25). And join them,
The oil chamber (11) on the ascending drive side of the hydraulic cylinder (11)
U), and is closer to the hydraulic cylinder (11) than the connection point (A) between the ascending drive side oil passage (50) and the oil passage (51) on the auxiliary control valve (25) side. In the ascending drive side oil passage (50) part, hydraulic oil is allowed to flow from the connection point (A) to the ascending drive side oil chamber (11U), and conversely is connected from the ascending drive side oil chamber (11U). A pilot check valve (52) for stopping the flow of hydraulic oil to the point (A) is provided, and the pilot check valve (52) is opened in synchronization with the operation of the control valve (21) to the lowered position (21D). A hydraulic circuit structure of a backhoe device comprising pilot operating means (54) and (55) for operating.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4211049A JP2702646B2 (en) | 1992-08-07 | 1992-08-07 | Hydraulic circuit structure of backhoe device |
| GB9313021A GB2269425B (en) | 1992-08-07 | 1993-06-24 | Hydraulic circuit structure for a backhoe implement |
| DE4324129A DE4324129C2 (en) | 1992-08-07 | 1993-07-19 | Hydraulic circuit structure for a backhoe tool |
| KR1019930014860A KR970000247B1 (en) | 1992-08-07 | 1993-07-31 | Hydraulic circuit structure for a backhole implement |
| FR9309731A FR2694604B1 (en) | 1992-08-07 | 1993-08-06 | HYDRAULIC CIRCUIT STRUCTURE FOR A BACKHOE. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4211049A JP2702646B2 (en) | 1992-08-07 | 1992-08-07 | Hydraulic circuit structure of backhoe device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0657786A true JPH0657786A (en) | 1994-03-01 |
| JP2702646B2 JP2702646B2 (en) | 1998-01-21 |
Family
ID=16599540
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4211049A Expired - Fee Related JP2702646B2 (en) | 1992-08-07 | 1992-08-07 | Hydraulic circuit structure of backhoe device |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP2702646B2 (en) |
| KR (1) | KR970000247B1 (en) |
| DE (1) | DE4324129C2 (en) |
| FR (1) | FR2694604B1 (en) |
| GB (1) | GB2269425B (en) |
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| US8966891B2 (en) | 2011-09-30 | 2015-03-03 | Caterpillar Inc. | Meterless hydraulic system having pump protection |
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|---|---|---|---|---|
| EP0866027B1 (en) * | 1997-03-21 | 2004-05-26 | Kabushiki Kaisha Toyota Jidoshokki | Hydraulic control apparatus for industrial vehicles |
| JP3339821B2 (en) * | 1998-06-29 | 2002-10-28 | 新キャタピラー三菱株式会社 | Work machine locking method and locking device |
| KR100559289B1 (en) * | 2002-06-14 | 2006-03-15 | 볼보 컨스트럭션 이키프먼트 홀딩 스웨덴 에이비 | hydraulic circuit of having float function |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6129813Y2 (en) * | 1980-07-07 | 1986-09-02 | ||
| DE3044143A1 (en) * | 1980-11-24 | 1982-06-24 | Linde Ag, 6200 Wiesbaden | CONTROL DEVICE FOR A HYDROSTATIC DRIVE SYSTEM |
| EP0059471B1 (en) * | 1981-03-03 | 1986-05-28 | Hitachi Construction Machinery Co., Ltd. | Hydrostatic drive system for civil engineering and construction machinery |
| KR870000506B1 (en) * | 1981-05-02 | 1987-03-12 | 니시모도 후미히라(西元文平) | Hydraulic circuit system for civil engineering and architectural machinery |
| JPS60211522A (en) * | 1984-04-05 | 1985-10-23 | Kubota Ltd | Operating structure of working truck |
| DE3811312A1 (en) * | 1988-04-02 | 1989-10-19 | Bosch Gmbh Robert | Double-acting working cylinder |
| JPH07116721B2 (en) * | 1989-01-31 | 1995-12-13 | 油谷重工株式会社 | Hydraulic circuit of hydraulic excavator |
| US4986072A (en) * | 1989-08-31 | 1991-01-22 | Kabushiki Kaisha Kobe Seiko Sho | Hydraulic actuator circuit with flow-joining control |
| JPH0630734A (en) * | 1992-07-20 | 1994-02-08 | Kenhachiro Nakamoto | Production of synthetic egg |
-
1992
- 1992-08-07 JP JP4211049A patent/JP2702646B2/en not_active Expired - Fee Related
-
1993
- 1993-06-24 GB GB9313021A patent/GB2269425B/en not_active Expired - Lifetime
- 1993-07-19 DE DE4324129A patent/DE4324129C2/en not_active Revoked
- 1993-07-31 KR KR1019930014860A patent/KR970000247B1/en not_active IP Right Cessation
- 1993-08-06 FR FR9309731A patent/FR2694604B1/en not_active Expired - Fee Related
Cited By (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8966892B2 (en) | 2011-08-31 | 2015-03-03 | Caterpillar Inc. | Meterless hydraulic system having restricted primary makeup |
| US8863509B2 (en) | 2011-08-31 | 2014-10-21 | Caterpillar Inc. | Meterless hydraulic system having load-holding bypass |
| US8944103B2 (en) | 2011-08-31 | 2015-02-03 | Caterpillar Inc. | Meterless hydraulic system having displacement control valve |
| US9151018B2 (en) | 2011-09-30 | 2015-10-06 | Caterpillar Inc. | Closed-loop hydraulic system having energy recovery |
| US9057389B2 (en) | 2011-09-30 | 2015-06-16 | Caterpillar Inc. | Meterless hydraulic system having multi-actuator circuit |
| US9051714B2 (en) | 2011-09-30 | 2015-06-09 | Caterpillar Inc. | Meterless hydraulic system having multi-actuator circuit |
| US8966891B2 (en) | 2011-09-30 | 2015-03-03 | Caterpillar Inc. | Meterless hydraulic system having pump protection |
| US8943819B2 (en) | 2011-10-21 | 2015-02-03 | Caterpillar Inc. | Hydraulic system |
| US8973358B2 (en) | 2011-10-21 | 2015-03-10 | Caterpillar Inc. | Closed-loop hydraulic system having force modulation |
| US8978373B2 (en) | 2011-10-21 | 2015-03-17 | Caterpillar Inc. | Meterless hydraulic system having flow sharing and combining functionality |
| US8978374B2 (en) | 2011-10-21 | 2015-03-17 | Caterpillar Inc. | Meterless hydraulic system having flow sharing and combining functionality |
| US8984873B2 (en) | 2011-10-21 | 2015-03-24 | Caterpillar Inc. | Meterless hydraulic system having flow sharing and combining functionality |
| US8919114B2 (en) | 2011-10-21 | 2014-12-30 | Caterpillar Inc. | Closed-loop hydraulic system having priority-based sharing |
| US8910474B2 (en) | 2011-10-21 | 2014-12-16 | Caterpillar Inc. | Hydraulic system |
| US9068578B2 (en) | 2011-10-21 | 2015-06-30 | Caterpillar Inc. | Hydraulic system having flow combining capabilities |
| US9080310B2 (en) | 2011-10-21 | 2015-07-14 | Caterpillar Inc. | Closed-loop hydraulic system having regeneration configuration |
| US8893490B2 (en) | 2011-10-21 | 2014-11-25 | Caterpillar Inc. | Hydraulic system |
| US9279236B2 (en) | 2012-06-04 | 2016-03-08 | Caterpillar Inc. | Electro-hydraulic system for recovering and reusing potential energy |
| US9290911B2 (en) | 2013-02-19 | 2016-03-22 | Caterpillar Inc. | Energy recovery system for hydraulic machine |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2694604B1 (en) | 1995-11-24 |
| GB2269425B (en) | 1995-11-22 |
| FR2694604A1 (en) | 1994-02-11 |
| DE4324129A1 (en) | 1994-02-10 |
| DE4324129C2 (en) | 1997-04-30 |
| GB9313021D0 (en) | 1993-08-11 |
| KR940005896A (en) | 1994-03-22 |
| GB2269425A (en) | 1994-02-09 |
| KR970000247B1 (en) | 1997-01-08 |
| JP2702646B2 (en) | 1998-01-21 |
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Legal Events
| Date | Code | Title | Description |
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| LAPS | Cancellation because of no payment of annual fees |