JPS6362608B2 - - Google Patents
Info
- Publication number
- JPS6362608B2 JPS6362608B2 JP56000770A JP77081A JPS6362608B2 JP S6362608 B2 JPS6362608 B2 JP S6362608B2 JP 56000770 A JP56000770 A JP 56000770A JP 77081 A JP77081 A JP 77081A JP S6362608 B2 JPS6362608 B2 JP S6362608B2
- Authority
- JP
- Japan
- Prior art keywords
- valve
- hydraulic
- operating
- servo valve
- directional control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000010276 construction Methods 0.000 claims description 10
- 239000003921 oil Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 5
- 239000010720 hydraulic oil Substances 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
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
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Operation Control Of Excavators (AREA)
- Fluid-Pressure Circuits (AREA)
Description
【発明の詳細な説明】
この発明は１つのアクチユエータを複数の直動
式方向切換弁からの圧油を合流させて作動する油
圧回路を有する土木建設機械の操作装置に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operating device for civil engineering and construction machinery having a hydraulic circuit that operates one actuator by merging pressure oil from a plurality of direct-acting directional control valves.
第１図は従来の土木建設機械の操作装置を有す
る油圧回路を示す図である。図において１，２は
油圧ポンプ、３，４は方向切換弁グループ、５は
タンク、６はアクチユエータ、７，８はアクチユ
エータ６に接続された方向切換弁、９，１０は方
向切換弁７，８の切換ロツド、１１は切換ロツド
９，１０を同時に移動するための操作機構であ
る。 FIG. 1 is a diagram showing a hydraulic circuit having an operating device for a conventional civil engineering construction machine. In the figure, 1 and 2 are hydraulic pumps, 3 and 4 are directional valve groups, 5 is a tank, 6 is an actuator, 7 and 8 are directional valves connected to the actuator 6, and 9 and 10 are directional valves 7 and 8 The switching rod 11 is an operating mechanism for simultaneously moving the switching rods 9 and 10.
この油圧回路においては、操作機構１１を操作
すると、方向切換弁７，８が同時に切換わり、油
圧ポンプ１，２の圧油が方向切換弁７，８を介
し、合流してアクチユエータ６に供給されるか
ら、アクチユエータ６の作動速度を大きくするこ
とができる。ところで、この操作装置において
は、２つの方向切換弁７，８を切換えるために、
操作機構１１により切換ロツド９，１０を移動す
るから、方向切換弁７，８を切換えるために大き
な操作力が必要であり、操作しづらい。 In this hydraulic circuit, when the operating mechanism 11 is operated, the directional switching valves 7 and 8 are simultaneously switched, and the pressure oil of the hydraulic pumps 1 and 2 is combined via the directional switching valves 7 and 8 and supplied to the actuator 6. Therefore, the operating speed of the actuator 6 can be increased. By the way, in this operating device, in order to switch the two directional switching valves 7 and 8,
Since the switching rods 9, 10 are moved by the operating mechanism 11, a large operating force is required to switch the directional switching valves 7, 8, making it difficult to operate.
第２図は従来の他の土木建設機械の操作装置を
有する油圧回路を示す図である。図において１２
は油圧ポンプ、１３は油圧ポンプ１２に接続され
たリリーフ弁、１４は油圧ポンプ１２の圧油によ
り作動するサーボ弁、１５はサーボ弁１４の入力
部材、１６はサーボ弁１４の出力部材で、出力部
材１６には切換ロツド９，１０が取付けられてい
る。 FIG. 2 is a diagram showing a hydraulic circuit having an operating device for another conventional civil engineering construction machine. In the figure 12
13 is a hydraulic pump, 13 is a relief valve connected to the hydraulic pump 12, 14 is a servo valve operated by the pressure oil of the hydraulic pump 12, 15 is an input member of the servo valve 14, 16 is an output member of the servo valve 14, and the output Attached to the member 16 are switching rods 9,10.
この操作装置においては、サーボ弁１４を介し
て２つの方向切換弁７，８を切換えるから、大き
な操作力を必要としない。しかしながら、この場
合には油圧ポンプ１２を設けなければならないか
ら、コスト高になるとともに、常時油圧ポンプ１
２を駆動しなければならないため、エネルギ損失
が大きく、また作動油温が上昇するので、作動油
の劣化が速いという欠点がある。 In this operating device, since the two directional control valves 7 and 8 are switched via the servo valve 14, a large operating force is not required. However, in this case, the hydraulic pump 12 must be provided, which increases the cost and requires the hydraulic pump 12 to be installed at all times.
2 must be driven, resulting in a large energy loss, and the temperature of the hydraulic oil increases, resulting in rapid deterioration of the hydraulic oil.
この発明は上述の問題点を解決するためになさ
れたもので、操作力が小さくて済み、かつ安価で
エネルギ損失が少なく、また作動油の劣化が速く
なることのない土木建設機械の操作装置を提供す
ることを目的とする。 This invention was made in order to solve the above-mentioned problems, and provides an operating device for civil engineering and construction machinery that requires less operating force, is inexpensive, has less energy loss, and does not cause rapid deterioration of hydraulic fluid. The purpose is to provide.
この目的を達成するため、この発明においては
第１、第２の油圧ポンプと、その第１、第２の油
圧ポンプにそれぞれ接続された第１、第２の方向
切換弁と、その第１の方向切換弁および第２の方
向切換弁に接続されたアクチエータとを有する土
木建設機械の操作装置において、出力部材が上記
第２の方向切換弁の切換ロツドに連結されたサー
ボ弁を設け、上記第１の方向切換弁の切換ロツド
および上記サーボ弁の入力部材を移動する操作機
構を設け、上記第１の方向切換弁のタンクポート
とタンクとの間に油圧を発生させる圧力発生装置
を設け、その圧力発生装置によつて発生した油圧
を上記サーボ弁の油圧ポートに導く。 In order to achieve this object, the present invention includes first and second hydraulic pumps, first and second directional control valves connected to the first and second hydraulic pumps, respectively, and the first and second hydraulic pumps. An operating device for civil engineering construction machinery having a directional control valve and an actuator connected to the second directional control valve, further comprising: a servo valve whose output member is connected to a switching rod of the second directional control valve; an operating mechanism for moving the switching rod of the first directional switching valve and the input member of the servo valve; a pressure generating device for generating hydraulic pressure between the tank port of the first directional switching valve and the tank; The hydraulic pressure generated by the pressure generator is guided to the hydraulic port of the servo valve.
第３図はこの発明に係る土木建設機械の操作装
置を有する油圧回路を示す図である。図において
１７は方向切換弁７のタンクポート１８とタンク
５との間に設けられたリリーフ弁、１９はサーボ
弁で、サーボ弁１９の油圧ポートにはリリーフ弁
１７によつて発生した油圧が導かれており、サー
ボ弁１９はこの油圧によつて作動する。２０はサ
ーボ弁１９の出力部材で、出力部材２０は切換ロ
ツド１０に連結されている。２１はサーボ弁１９
の入力部材、２２は切換ロツド９と入力部材２１
を同時に移動するための操作機構である。 FIG. 3 is a diagram showing a hydraulic circuit having an operating device for a civil engineering construction machine according to the present invention. In the figure, 17 is a relief valve provided between the tank port 18 of the directional control valve 7 and the tank 5, 19 is a servo valve, and the hydraulic pressure generated by the relief valve 17 is introduced to the hydraulic port of the servo valve 19. The servo valve 19 is operated by this oil pressure. 20 is an output member of the servo valve 19, and the output member 20 is connected to the switching rod 10. 21 is the servo valve 19
22 is the switching rod 9 and the input member 21.
This is an operating mechanism for moving both at the same time.
この操作装置においては、操作機構２２を操作
すれば、方向切換弁７が切換ロツド９を介して切
換えられ、油圧ポンプ１の圧油が方向切換弁７を
介してアクチユエータ６に供給されるから、アク
チユエータ６が作動する。このため、アクチユエ
ータ６からの戻り油がタンクポート１８を介して
タンク５に戻るが、リリーフ弁１７のためにリリ
ーフ弁１７の上流側に圧力が発生し、この圧力が
サーボ弁１９に供給される。したがつて、方向切
換弁８がサーボ弁１９、切換ロツド１０を介して
切換えられる。この場合、方向切換弁８はサーボ
弁１９を介して切換えられるから、操作機構２２
の操作力は１つの方向切換弁を切換えるのに要す
る操作力はほぼ同じである。 In this operating device, when the operating mechanism 22 is operated, the directional switching valve 7 is switched via the switching rod 9, and the pressure oil of the hydraulic pump 1 is supplied to the actuator 6 via the directional switching valve 7. Actuator 6 is activated. Therefore, the return oil from the actuator 6 returns to the tank 5 via the tank port 18, but pressure is generated upstream of the relief valve 17 due to the relief valve 17, and this pressure is supplied to the servo valve 19. . Therefore, the directional control valve 8 is switched via the servo valve 19 and the switching rod 10. In this case, since the directional control valve 8 is switched via the servo valve 19, the operating mechanism 22
The operating force required to switch one directional control valve is approximately the same.
第４図は第３図に示した操作装置のサーボ弁の
一例を示す断面図である。図において２３はサー
ボ弁本体、２４はサーボ弁本体２３内に摺動可能
に設けられたスリーブで、スリーブ２４は出力部
材２０と一体である。２５はサーボ弁本体２３、
スリーブ２４に摺動可能に設けられたスプール
で、スプール２５は入力部材２１と一体である。
２６はサーボ弁本体２３に設けられた圧油ポート
で圧油ポート２６はリリーフ弁１７の上流側と接
続されている。２７はサーボ弁本体２３に設けら
れたタンクポートで、タンクポート２７はタンク
５に接続されている。２８〜３３は弁室、３４〜
３６は流路、３７はスプール２５のランドであ
る。 FIG. 4 is a sectional view showing an example of the servo valve of the operating device shown in FIG. 3. In the figure, 23 is a servo valve main body, 24 is a sleeve slidably provided within the servo valve main body 23, and the sleeve 24 is integrated with the output member 20. 25 is a servo valve main body 23;
A spool is slidably provided on the sleeve 24, and the spool 25 is integral with the input member 21.
26 is a pressure oil port provided in the servo valve body 23, and the pressure oil port 26 is connected to the upstream side of the relief valve 17. 27 is a tank port provided in the servo valve body 23, and the tank port 27 is connected to the tank 5. 28-33 are valve chambers, 34-
36 is a flow path, and 37 is a land of the spool 25.
このサーボ弁１９においては、図示の状態から
入力部材２１を右方に動かすと、弁室２９と弁室
３０とが連通するため、圧油ポート２６の圧油が
弁室２８、流路３４、弁室２９、流路３５を介し
て弁室３２に導かれ、また弁室３２の受圧面積は
弁室２８の受圧面積よりも大であるから、出力部
材２０も右方に移動する。そして、出力部材２０
が所定距離だけ移動して、ランド３７により弁室
２９と弁室３０との連通が遮断されると、弁室３
２に圧油が導かれなくなるから、出力部材２０が
停止する。また、入力部材２１を左方に動かす
と、弁室２９と弁室３１とが連通するため、弁室
３２が流路３５、弁室２９、弁室３１、流路３
６、弁室３３、タンクポート２７を介してタンク
５と連通するので、弁室３２の圧力が低下し、ま
た弁室２８には圧油が供給されているから、出力
部材２０も左方に移動する。そして、出力部材２
０が所定距離だけ移動して、ランド３７により弁
室２９と弁室３１との連通が遮断されると、弁室
３２とタンク５との連通が遮断されるから、出力
部材２０が停止する。このように、入力部材２１
の移動に応じて出力部材２０が移動し、また入力
部材２１を小さな操作力で移動することができる
から、小さな操作力で方向切換弁８を切換えるこ
とができる。 In this servo valve 19, when the input member 21 is moved to the right from the illustrated state, the valve chamber 29 and the valve chamber 30 communicate with each other, so that the pressure oil in the pressure oil port 26 is transferred to the valve chamber 28, the flow path 34, It is guided to the valve chamber 32 via the valve chamber 29 and the flow path 35, and since the pressure receiving area of the valve chamber 32 is larger than the pressure receiving area of the valve chamber 28, the output member 20 also moves to the right. And output member 20
moves a predetermined distance and the land 37 blocks communication between the valve chamber 29 and the valve chamber 30.
2, the output member 20 stops. Furthermore, when the input member 21 is moved to the left, the valve chamber 29 and the valve chamber 31 communicate with each other.
6. Since the valve chamber 33 communicates with the tank 5 through the tank port 27, the pressure in the valve chamber 32 decreases, and since pressure oil is supplied to the valve chamber 28, the output member 20 also moves to the left. Moving. And output member 2
0 moves a predetermined distance and the land 37 blocks the communication between the valve chamber 29 and the valve chamber 31, the communication between the valve chamber 32 and the tank 5 is cut off, and the output member 20 stops. In this way, the input member 21
Since the output member 20 moves in accordance with the movement of the input member 20 and the input member 21 can be moved with a small operating force, the directional switching valve 8 can be switched with a small operating force.
第５図は第３図に示した操作装置の操作機構の
一例を示す斜視図である。図において３８は回転
可能に支持された部材、３９は部材３８に固定さ
れた操作レバー、４０，４１は部材３８に固定さ
れたブラケツト、４２はブラケツト４０に設けら
れた穴、４３はブラケツト４１に設けられた長穴
で、第６図に示すように、部材３８の回転中心と
長穴４３の中心との距離は、部材３８の回転中心
と穴４２の中心との距離より大きい。４４は穴４
２を介して切換ロツド９をブラケツト４０に取付
けるためのピン、４５は長穴４３を介して入力部
材２１をブラケツト４１に取付けるためのピンで
ある。 5 is a perspective view showing an example of the operating mechanism of the operating device shown in FIG. 3. FIG. In the figure, 38 is a rotatably supported member, 39 is an operating lever fixed to member 38, 40 and 41 are brackets fixed to member 38, 42 is a hole provided in bracket 40, and 43 is a hole provided in bracket 41. As shown in FIG. 6, the distance between the rotation center of the member 38 and the center of the elongated hole 43 is larger than the distance between the rotation center of the member 38 and the center of the hole 42. 44 is hole 4
2 is a pin for attaching the switching rod 9 to the bracket 40, and 45 is a pin for attaching the input member 21 to the bracket 41 via the elongated hole 43.
この操作機構においては、操作レバー３９を操
作すると、部材３８が回転し、穴４２、長穴４３
がを円弧状に動く。このとき、ピン４４は穴４２
に嵌合されているので、第７図の直線で示すよ
うに、切換ロツド９は操作レバー３９の動きに応
じて動くが、ピン４５は長穴４３に嵌合されてい
るので、第７図の直線に示すように、入力部材
２１はすぐには動かず、操作レバー３９のストロ
ークＬがL1になつたとき動き始める。そして、
部材３８の回転中心と長穴４３の中心との距離
は、部材３８の回転中心と長穴４３の中心との距
離より大きいから、操作レバー３９のストローク
Ｌを最大Lnaxにしたときには、両方の方向切換弁
７，８のストロークＳが最大Snaxになる。そし
て、この操作機構を用いたときには、方向切換弁
７を方向切換弁８に先行して切換えることができ
るから、サーボ弁１９が作動される前に、サーボ
弁１９を作動するに十分な圧力が供給されるの
で、操作力が非常に小さくて済む。また、操作レ
バー３９を微操作したときには、方向切換弁７の
みが切換えられ、アクチユエータ６には油圧ポン
プ１の圧油のみが供給されるから、アクチユエー
タ６の作動速度が小さく、アクチユエータ６の微
動操作が容易である。 In this operating mechanism, when the operating lever 39 is operated, the member 38 is rotated, and the hole 42 and the elongated hole 43 are rotated.
moves in an arc. At this time, the pin 44 is inserted into the hole 42.
Since the pin 45 is fitted into the elongated hole 43, the switching rod 9 moves in accordance with the movement of the operating lever 39, as shown by the straight line in FIG. As shown by the straight line, the input member 21 does not move immediately, but starts moving when the stroke L of the operating lever 39 reaches L1 . and,
Since the distance between the rotation center of the member 38 and the center of the elongated hole 43 is greater than the distance between the rotation center of the member 38 and the center of the elongated hole 43, when the stroke L of the operating lever 39 is set to the maximum L nax , both The stroke S of the directional control valves 7 and 8 becomes the maximum S nax . When using this operating mechanism, the directional switching valve 7 can be switched before the directional switching valve 8, so that sufficient pressure to operate the servo valve 19 is generated before the servo valve 19 is operated. Since the power is supplied, only a very small amount of operating force is required. Furthermore, when the operating lever 39 is slightly operated, only the directional control valve 7 is switched and only the pressure oil from the hydraulic pump 1 is supplied to the actuator 6, so the operating speed of the actuator 6 is small and the actuator 6 is operated slightly. is easy.
なお、上述実施例においては、圧力発生装置と
してリリーフ弁１７を設けたが、圧力発生装置と
して絞り弁を設けてもよいし、絞り弁とリリーフ
弁を並列に接続したものを設けてもよい。また、
操作機構２２も第５図に示したものに限定されな
い。 In the above-described embodiment, the relief valve 17 is provided as the pressure generating device, but a throttle valve may be provided as the pressure generating device, or a throttle valve and a relief valve connected in parallel may be provided. Also,
The operating mechanism 22 is also not limited to that shown in FIG.
以上説明したように、この発明に係る土木建設
機械の操作装置においては、サーボ弁により方向
切換弁を切換えるから、操作力が小さくて済むと
ともに、サーボ弁を作動するための油圧ポンプを
設けないから、安価であり、またアクチユエータ
を作動しようとするときのみ、サーボ弁を作動す
るための圧力が発生するため、エネルギ損失が小
さく、かつ作動油温の上昇も少ないので、作動油
の劣化が速くなることもない。このように、この
発明の効果は顕著である。 As explained above, in the operating device for civil engineering construction machinery according to the present invention, since the directional control valve is switched by the servo valve, the operating force is small, and a hydraulic pump for operating the servo valve is not provided. , is inexpensive, and because the pressure to operate the servo valve is generated only when the actuator is to be operated, energy loss is small and the rise in hydraulic oil temperature is also small, so the hydraulic oil deteriorates more quickly. Not at all. As described above, the effects of this invention are remarkable.
第１図、第２図はそれぞれ従来の土木建設機械
の操作装置を有する油圧回路を示す図、第３図は
この発明に係る土木建設機械の操作装置を有する
油圧回路を示す図、第４図は第３図に示した操作
装置のサーボ弁の一例を示す断面図、第５図は第
３図に示した操作装置の操作機構の一例を示す斜
視図、第６図は第５図に示した操作機構の動作説
明図、第７図は第５図に示した操作機構の動作を
説明するためのグラフである。
１，２……油圧ポンプ、３，４……方向切換弁
グループ、６……アクチユエータ、７，８……方
向切換弁、１７……リリーフ弁、１８……タンク
ポート、１９……サーボ弁、２０……出力部材、
２１……入力部材、２２……操作機構、３８……
部材、３９……操作レバー、４０，４１……ブラ
ケツト、４２……穴、４３……長穴、４４，４５
……ピン。
1 and 2 are diagrams showing a hydraulic circuit having an operating device for a conventional civil engineering and construction machine, respectively. FIG. 3 is a diagram showing a hydraulic circuit having an operating device for a civil engineering and construction machine according to the present invention, and FIG. is a sectional view showing an example of the servo valve of the operating device shown in FIG. 3, FIG. 5 is a perspective view showing an example of the operating mechanism of the operating device shown in FIG. 3, and FIG. FIG. 7 is a graph for explaining the operation of the operating mechanism shown in FIG. 5. 1, 2... Hydraulic pump, 3, 4... Directional switching valve group, 6... Actuator, 7, 8... Directional switching valve, 17... Relief valve, 18... Tank port, 19... Servo valve, 20...output member,
21...Input member, 22...Operation mechanism, 38...
Member, 39... Operating lever, 40, 41... Bracket, 42... Hole, 43... Oblong hole, 44, 45
……pin.
Claims (1)
の油圧ポンプにそれぞれ接続された第１、第２の
方向切換弁と、その第１の方向切換弁および第２
の方向切換弁に接続されたアクチエータとを有す
る土木建設機械の操作装置において、出力部材が
上記第２の方向切換弁の切換ロツドに連結された
サーボ弁を設け、上記第１の方向切換弁の切換ロ
ツドおよび上記サーボ弁の入力部材を移動する操
作機構を設け、上記第１の方向切換弁のタンクポ
ートとタンクとの間に油圧を発生させる圧力発生
装置を設け、その圧力発生装置によつて発生した
油圧を上記サーボ弁の油圧ポートに導いたことを
特徴とする土木建設機械の操作装置。1 First and second hydraulic pumps and their first and second hydraulic pumps;
a first directional control valve and a second directional control valve respectively connected to a hydraulic pump;
an actuator connected to a directional control valve, a servo valve having an output member connected to a switching rod of the second directional control valve; An operating mechanism for moving the switching rod and the input member of the servo valve is provided, a pressure generating device is provided for generating hydraulic pressure between the tank port of the first directional switching valve and the tank, and the pressure generating device An operating device for civil engineering and construction machinery, characterized in that the generated hydraulic pressure is guided to a hydraulic port of the servo valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP77081A JPS57116840A (en) | 1981-01-08 | 1981-01-08 | Operating device for civil engineering work and construction machinery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP77081A JPS57116840A (en) | 1981-01-08 | 1981-01-08 | Operating device for civil engineering work and construction machinery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57116840A JPS57116840A (en) | 1982-07-21 |
| JPS6362608B2 true JPS6362608B2 (en) | 1988-12-02 |
Family
ID=11482923
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP77081A Granted JPS57116840A (en) | 1981-01-08 | 1981-01-08 | Operating device for civil engineering work and construction machinery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57116840A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS612567U (en) * | 1984-06-07 | 1986-01-09 | ハンド−ザ−工業株式会社 | Hydraulic pump merging device for earthmoving vehicles |
| JPS612568U (en) * | 1984-06-12 | 1986-01-09 | ハンド−ザ−工業株式会社 | Hydraulic pump merging device for earthmoving vehicles |
| JP6377520B2 (en) * | 2014-12-26 | 2018-08-22 | 株式会社クボタ | Work system hydraulic system and work machine equipped with the hydraulic system |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5513254B2 (en) * | 1976-12-29 | 1980-04-08 |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54148004U (en) * | 1978-04-05 | 1979-10-15 | ||
| JPS5513254U (en) * | 1978-07-10 | 1980-01-28 |
-
1981
- 1981-01-08 JP JP77081A patent/JPS57116840A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5513254B2 (en) * | 1976-12-29 | 1980-04-08 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57116840A (en) | 1982-07-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3771564A (en) | Pilot control valve | |
| US3871178A (en) | Variable output pump control circuit using a remote control | |
| US3906727A (en) | Hydrostatic drive with direction memory | |
| JPS6362608B2 (en) | ||
| US3862645A (en) | Pilot control valve | |
| JPS612908A (en) | Control valve device | |
| JPS6242145B2 (en) | ||
| JPH02566B2 (en) | ||
| JP2630775B2 (en) | Priority operation control device for high load actuator | |
| JPS58113602A (en) | Liquid pressure control device | |
| JPS5825161B2 (en) | Merging hydraulic circuit | |
| JPS6139551B2 (en) | ||
| JPS5918561B2 (en) | Pressure control servo device | |
| JPS6144005Y2 (en) | ||
| JPH02484Y2 (en) | ||
| JP3344745B2 (en) | Hydraulic control circuit | |
| JP3346211B2 (en) | Hydraulic circuit of work machine | |
| RU2096226C1 (en) | Vehicle hydraulic steering gear | |
| JP2873399B2 (en) | Hydraulic control device for construction machinery | |
| JPH06123303A (en) | Oil pressure controller | |
| JPH0318015B2 (en) | ||
| JPH10331997A (en) | Electrohydraulic servo valve | |
| JPS603419Y2 (en) | select valve | |
| JPS5917004A (en) | Fluid control valve | |
| JPS6114646Y2 (en) |