JPH0346246Y2 - - Google Patents
Info
- Publication number
- JPH0346246Y2 JPH0346246Y2 JP1984171636U JP17163684U JPH0346246Y2 JP H0346246 Y2 JPH0346246 Y2 JP H0346246Y2 JP 1984171636 U JP1984171636 U JP 1984171636U JP 17163684 U JP17163684 U JP 17163684U JP H0346246 Y2 JPH0346246 Y2 JP H0346246Y2
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- receiving chamber
- pressure receiving
- pressure oil
- spool
- 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
- 230000007423 decrease Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Forklifts And Lifting Vehicles (AREA)
- Fluid-Pressure Circuits (AREA)
Description
【考案の詳細な説明】
（産業上の利用分野）
本考案はフオークリフトやクレーンにおけるリ
フトシリンダの上昇速度等を切り換えるのに好適
な油圧駆動装置における駆動速度切換装置に関す
る。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a drive speed switching device in a hydraulic drive device suitable for switching the lifting speed, etc. of a lift cylinder in a forklift or a crane.
（従来の技術）
第４図において、１，２はポンプ、３は方向切
換弁、４はリフトシリンダ、５は逆止片、６は速
度切換弁、７は荷重検知弁である。図において、
積荷をリフトシリンダ４で上昇させているとき、
積荷が軽いと荷重検知弁は切換わらず、速度切換
弁６のスプール８も図に示す位置にあるので、ポ
ンプ２の圧油は逆止弁５を通つてポンプ１の圧油
と合流し、積荷を早く上昇させる。積荷が重いと
きは、荷重検知弁７のパイロツト回路９の圧力が
あがり、弁７を切換えて、圧油が速度切換弁６に
送られスプール８を左に移動させる。(Prior Art) In FIG. 4, 1 and 2 are pumps, 3 is a directional switching valve, 4 is a lift cylinder, 5 is a check piece, 6 is a speed switching valve, and 7 is a load detection valve. In the figure,
When the load is being lifted by the lift cylinder 4,
If the load is light, the load detection valve does not switch, and the spool 8 of the speed switching valve 6 is also in the position shown in the figure, so the pressure oil of the pump 2 passes through the check valve 5 and merges with the pressure oil of the pump 1. Raise the load quickly. When the load is heavy, the pressure in the pilot circuit 9 of the load detection valve 7 increases, the valve 7 is switched, and pressure oil is sent to the speed switching valve 6 to move the spool 8 to the left.
そのため、ポンプ２の圧油は切換られて、タン
クポート１０にバイパスされ、積荷はポンプ１だ
けの圧油で上昇するので、上昇速度は遅くなる。 Therefore, the pressure oil of the pump 2 is switched and bypassed to the tank port 10, and the cargo is lifted using only the pressure oil of the pump 1, so that the lifting speed becomes slow.
（考案が解決しようとする課題） 前述の従来技術には次のような問題点がある。(The problem that the idea aims to solve) The above-mentioned conventional technology has the following problems.
積荷の重量が、荷重切換弁の切換圧力に近いと
きは、積荷を上昇中に切換弁７が、切換つたり、
戻つたりするため、速度が変化するハンチングと
いう現象をおこし積荷がくずれたりする危険があ
る。 When the weight of the cargo is close to the switching pressure of the load switching valve, the switching valve 7 switches and switches while the cargo is being lifted.
This causes a phenomenon called hunting, in which the speed changes, and there is a danger that the cargo may collapse.
特にフオークリフトのマストの角度をかえた
り、エンジンの回転数をかえたりするとリフトシ
リンダの荷重が変わり圧力変動するので、ハンチ
ングをおこしやすい。 In particular, changing the mast angle of a forklift or changing the engine speed changes the load on the lift cylinder and causes pressure fluctuations, which can easily cause hunting.
本考案は、上記の従来技術における問題点を解
消し、特に大出力の動力源を必要とせず、且つハ
ンチングの発生を防止した油圧駆動装置における
駆動速度切換装置を提供することを目的とするも
のである。 The object of the present invention is to provide a drive speed switching device for a hydraulic drive device that eliminates the problems in the prior art described above, does not require a particularly high-output power source, and prevents the occurrence of hunting. It is.
（課題を解決するための手段）
複数のポンプから吐出された圧油を分流又は合
流させてアクチユエータに供給することによりア
クチユエータの駆動速度を切り換えるようにした
油圧駆動装置における駆動速度切換装置におい
て、１のポンプから吐出された圧油を他のポンプ
からアクチユエータに至る圧油供給路に合流させ
るか又は上記他のポンプからの圧油のみをタンク
にバイパスさせるかを選択的に切り換えるバイパ
ススプールと、このバイパススプールを駆動する
パイロツトスプールとを具え、上記パイロツトス
プールの片側に上記圧油供給路内の圧油が作用す
る第１の受圧室を形成するとともに、他側に上記
１のポンプから吐出された圧油が作用する上記第
１の受圧室の受圧面積より小さい受圧面積を有す
る第２の受圧室を形成し、上記パイロツトスプー
ルを上記第１の受圧室の方向に所定の圧力で押圧
するばねを設け、上記パイロツトスプールの外周
に上記第１の受圧室とバイパススプールの受圧室
との間の連通路を開閉するランド部を形成する。(Means for Solving the Problems) In a drive speed switching device for a hydraulic drive device, the drive speed of an actuator is switched by dividing or merging pressure oil discharged from a plurality of pumps and supplying the same to the actuator. a bypass spool for selectively switching whether to allow the pressure oil discharged from the pump to join the pressure oil supply path leading from the other pump to the actuator, or to bypass only the pressure oil from the other pump to the tank; a pilot spool for driving a bypass spool; one side of the pilot spool forms a first pressure receiving chamber on which the pressure oil in the pressure oil supply path acts; and the other side forms a first pressure receiving chamber on which pressure oil is discharged from the first pump A second pressure receiving chamber is formed having a pressure receiving area smaller than the pressure receiving area of the first pressure receiving chamber on which pressure oil acts, and a spring is provided to press the pilot spool in the direction of the first pressure receiving chamber with a predetermined pressure. A land portion is formed on the outer periphery of the pilot spool to open and close a communication path between the first pressure receiving chamber and the pressure receiving chamber of the bypass spool.
（作用）
アクチユエータの負荷が小さいときは、第１の
受圧室内の圧油の圧力が低く、従つて、パイロツ
トスプールが切り換わらないので、バイパススプ
ールは駆動されず、この結果、１のポンプから吐
出された圧油は他のポンプからアクチユエータに
至る圧油供給路に合流してアクチユエータに供給
されるので、アクチユエータは高速で駆動され
る。(Function) When the load on the actuator is small, the pressure of the pressure oil in the first pressure receiving chamber is low, and therefore the pilot spool does not switch, so the bypass spool is not driven, and as a result, the discharge from the first pump is reduced. The released pressure oil joins a pressure oil supply path from another pump to the actuator and is supplied to the actuator, so the actuator is driven at high speed.
アクチユエータの負荷が大きいときは、第１の
受圧室内の圧油の圧力が上昇するので、パイロツ
トスプールが切り換り、これによつてバイパスス
プールが駆動される結果、１のポンプから吐出さ
れた圧油はタンクにバイパスされ、アクチユエー
タには他のポンプから吐出された圧油のみが供給
され、アクチユエータは低速で駆動される。パイ
ロツトスプールがその片側に向つて移動する場合
と、他側に向つて移動する場合とでは、第１の受
圧室内の圧油の圧力に差が出るため、パイロツト
スプールの不安定な動きが抑止される。 When the load on the actuator is large, the pressure of the pressure oil in the first pressure receiving chamber increases, so the pilot spool is switched, which drives the bypass spool, and as a result, the pressure discharged from the first pump increases. The oil is bypassed to the tank, and the actuator is supplied only with pressure oil discharged from other pumps, and the actuator is driven at low speed. When the pilot spool moves toward one side and when it moves toward the other side, there is a difference in the pressure of the pressure oil in the first pressure receiving chamber, so unstable movement of the pilot spool is suppressed. Ru.
（実施例）
本考案の実施例を図面を参照しながら具体的に
説明する。(Example) An example of the present invention will be specifically described with reference to the drawings.
第１図ないし第３図において、１，２はポン
プ、３は方向切換弁、４はリフトシリンダ、５，
６は逆止弁、７は速度切換弁である。速度切換弁
７の弁体１０はこれを貫通して平行に延びる２つ
のボア２７，２８を具え、ボア２７，２８の右側
は右蓋２９で掩蓋され、左端は左蓋３０で掩蓋さ
れている。ボア２８はその内面に凹溝１８，３
１，３２を具え、ボア２７内には油密摺動自在に
パイロツトスプール１３が嵌挿され、このパイロ
ツトスプール１３の左側にバネ受３３と１体のス
トツパ３４が収納されている。このストツパ３３
の外周に巻回されたばね１４の左端はバネ受３３
に当接し、右端はパイロツトスプール１３の左端
に当接せしめられ、このばね１４によつてパイロ
ツトスプール１３は右方へ付勢されている。パイ
ロツトスプール１３はランド１３ａ，１３ｂ，１
３ｃを具えると共に、その左側端よりその軸方向
に穿設された腔所３５を具え、この腔所３５内に
油密摺動自在に嵌挿されたスラグ１５の左端はパ
イロツトスプール１３の左側端より左側へ進出し
てストツパ３４の右端に衝接している。スラグ１
５の右端は腔所３５と協働して受圧室２０を画成
し、この受圧室２０は油孔１９を介してランド１
３ａと１３ｂとの間に開口せしめられている。 In Figures 1 to 3, 1 and 2 are pumps, 3 is a directional valve, 4 is a lift cylinder, 5,
6 is a check valve, and 7 is a speed switching valve. The valve body 10 of the speed switching valve 7 has two bores 27 and 28 extending in parallel through it, and the right sides of the bores 27 and 28 are covered with a right cover 29, and the left ends are covered with a left cover 30. . The bore 28 has grooves 18, 3 on its inner surface.
1 and 32, and a pilot spool 13 is fitted into the bore 27 in an oil-tight and slidable manner, and a spring receiver 33 and a stopper 34 are housed on the left side of the pilot spool 13. This stopper 33
The left end of the spring 14 wound around the outer periphery of the spring receiver 33
The right end is brought into contact with the left end of the pilot spool 13, and the pilot spool 13 is biased to the right by the spring 14. The pilot spool 13 has lands 13a, 13b, 1
3c, and a cavity 35 bored in the axial direction from its left end, and the left end of the slug 15, which is slidably and oil-tightly fitted into this cavity 35, is located on the left side of the pilot spool 13. It advances to the left side from the end and collides with the right end of the stopper 34. Slag 1
The right end of 5 cooperates with the cavity 35 to define a pressure receiving chamber 20, and this pressure receiving chamber 20 is connected to the land 1 through the oil hole 19.
It is opened between 3a and 13b.
一方、ボア２７はその内面に凹溝３６，２３，
２４，３７を具え、このボア２７内には油密摺動
自在にバイパス用スプール１１が嵌挿されてい
る。このスプール１１はランド１１ａ，１１ｂを
具え、その左側端よりその軸方向に穿設された腔
所３８に収納されたばね１２の左端は左蓋３０に
当接し、右端は腔所３８の底に当接して、このば
ね１２によつてスプール１１は右方へ付勢されて
いる。凹溝２３はドレンポート３９に油孔４０に
よつて連通せしめられ、ドレーンポート３９は管
路４１を介してドレンタンク２６に連通されてい
る。凹溝２４は油孔４２を介して凹溝１８に連通
せしめられるとともに圧油ポート４３に油孔４５
を介して連通せしめられ、圧油ポート４３は管路
４４を介してポンプ２の吐出口に連通されてい
る。バイパススプール１１の右側に限界された受
圧室２２は凹溝３７及び油孔２１を介して凹溝３
２に連通せしめられている。パイロツトスプール
１３の左側に限界された室４６及び凹溝３１はそ
れぞれドレン通路２５を介して凹溝２３に連通せ
しめられ、バイパススプール１１の左側に限界さ
れた室４７も凹溝３６、ドレン通路２５を介して
凹溝２３に連通せしめられている。パイロツトス
プール１３の右側に限界された受圧室１７は右蓋
２９に穿設された油孔４８、管路１６を介してポ
ンプ１と方向切換弁３を接続する管路４９に連通
せしめられている。管路４９から分岐した一方の
分岐路４９ａに逆止弁６が方向切換弁３への油の
流れのみを許容するように介装されている。ま
た、管路４９と管路４４を接続する管路５０に逆
止弁５が管路４９への油の流れのみを許容するよ
うに介装されている。５１はリフトシリンダ４の
押側室と方向切換弁３とを接続する管路、５２は
方向切換弁３とドレンタンク２６とを接続する管
路である。 On the other hand, the bore 27 has concave grooves 36, 23 on its inner surface.
24 and 37, and the bypass spool 11 is fitted into the bore 27 so as to be slidable in an oil-tight manner. This spool 11 has lands 11a and 11b, and the left end of the spring 12, which is housed in a cavity 38 bored in the axial direction from the left end thereof, contacts the left lid 30, and the right end contacts the bottom of the cavity 38. The spool 11 is urged to the right by the spring 12. The groove 23 communicates with the drain port 39 through an oil hole 40, and the drain port 39 communicates with the drain tank 26 via a pipe line 41. The groove 24 is communicated with the groove 18 through the oil hole 42, and the oil hole 45 is connected to the pressure oil port 43.
The pressure oil port 43 is communicated with the discharge port of the pump 2 via a conduit 44. The pressure receiving chamber 22 limited to the right side of the bypass spool 11 is connected to the groove 3 via the groove 37 and the oil hole 21.
2 is connected. The chamber 46 and groove 31 bounded on the left side of the pilot spool 13 are communicated with the groove 23 via the drain passage 25, respectively, and the chamber 47 confined on the left side of the bypass spool 11 also communicates with the groove 36 and the groove 25 It is communicated with the concave groove 23 via. A pressure receiving chamber 17 limited to the right side of the pilot spool 13 is communicated with a pipe line 49 connecting the pump 1 and the directional control valve 3 via an oil hole 48 bored in the right cover 29 and a pipe line 16. . A check valve 6 is interposed in one branch line 49a branching from the pipe line 49 so as to allow oil to flow only to the directional control valve 3. Further, a check valve 5 is interposed in a conduit 50 that connects the conduit 49 and the conduit 44 so as to allow oil to flow only into the conduit 49. 51 is a conduit connecting the push side chamber of the lift cylinder 4 and the directional control valve 3; 52 is a conduit connecting the directional control valve 3 and the drain tank 26.
リフトシリンダ４を空荷で上昇させる場合に
は、第１図に示すように方向切換弁３を図示の３
ａ位置に切り換える。すると、ポンプ１から吐出
された圧油は管路４９、分岐路４９ａ、逆止弁
６、方向切換弁３、管路５１をこの順に経てリフ
トシリンダ４の押側室内に流入し、リフトシリン
ダ４を上昇させる。この際、圧油の１部が管路４
９から管路１６、油孔４８を介して受圧室１７内
に流入し、パイロツトスプール１３を左方へ押推
する。一方、ポンプ２から吐出された圧油は管路
４４、圧油ポート４３、油孔４５、凹溝２４、油
孔４２、凹溝１８、油孔１９を経て受圧室２０に
流入し、パイロツトスプール１３を右方へ押推す
る。この場合、リフトシリンダ４が空荷なので管
路４９内の圧油の圧力は上昇せず、従つて、受圧
室１７に作用する油圧力は小さいのでパイロツト
スプール１３はばね１４によつて右方に押圧され
ることにより図示の位置を占める。かくして、ポ
ンプ２から吐出された圧油は管路５０に介装され
た逆止弁５を開いて管路４９に流入し、ポンプ１
から吐出された圧油と合流してリフトシリンダ４
に供給される。この結果、リフトシリンダ４は２
個のポンプ１，２から吐出された圧油が供給され
るので高速で上昇する。 When lifting the lift cylinder 4 with no load, as shown in FIG.
Switch to position a. Then, the pressure oil discharged from the pump 1 flows into the push side chamber of the lift cylinder 4 through the pipe line 49, the branch line 49a, the check valve 6, the directional control valve 3, and the pipe line 51 in this order. raise. At this time, part of the pressure oil is transferred to the pipe 4.
9 flows into the pressure receiving chamber 17 through the pipe line 16 and the oil hole 48, and pushes the pilot spool 13 to the left. On the other hand, the pressure oil discharged from the pump 2 flows into the pressure receiving chamber 20 through the pipe line 44, the pressure oil port 43, the oil hole 45, the groove 24, the oil hole 42, the groove 18, and the oil hole 19. Push 13 to the right. In this case, since the lift cylinder 4 is empty, the pressure of the pressure oil in the conduit 49 does not increase, and therefore the hydraulic pressure acting on the pressure receiving chamber 17 is small, so the pilot spool 13 is moved to the right by the spring 14. When pressed, it assumes the position shown. In this way, the pressure oil discharged from the pump 2 opens the check valve 5 installed in the pipe line 50 and flows into the pipe line 49, and the pump 1
It joins with the pressure oil discharged from the lift cylinder 4.
supplied to As a result, the lift cylinder 4 is
Since the pressure oil discharged from the pumps 1 and 2 is supplied, it rises at high speed.
リフトシリンダ４を積荷状態で上昇させる場合
の状態が第２図に示されている。方向切換弁３を
上記と同様３ａ位置に切り換えると、ポンプ１か
ら吐出された圧油は上記と同様リフトシリンダ４
の押側室内に流入するが、リフトシリンダ４は積
荷状態にあるので、管路４９内の圧油の圧力が上
昇する。そして、この圧油が管路１６、油孔４８
を経て受圧室１７内に流入する。一方、ポンプ２
から吐出された圧油が管路４４、圧油ポート４
３、油孔４５、凹溝２４、油孔４２、凹溝１８、
油孔１９を経て受圧室２０に入るが、受圧室２０
の受圧面積より受圧室１７の受圧面積の方が大き
いので、受圧室１７内に流入した圧油によりパイ
ロツトスプール１３はばね１４の押圧力に抗して
左方に移動して図示の位置を占める。すると、受
圧室１７内の圧油が油孔２１、凹溝３７を経て受
圧室２２に流入して、第３図に示すように、バイ
パススプール１１をばね１２に抗して左方に移動
させる。その結果、凹溝２４と凹溝２３とが連通
するので、ポンプ２から吐出された圧油は管路４
４、圧油ポート４３、油孔４５、凹溝２４，２
３、油孔４０、ドレンポート３９、管路４１をこ
の順に通つてドレンタンク２６に排出される。か
くして、リフトシリンダ４に供給される圧油はポ
ンプ１から吐出された圧油だけとなり、リフトシ
リンダ４は低速で上昇する。なお、パイロツトス
プール１３の左行及びバイパススプール１１の左
行に伴つて、室４６，４７内の油は油孔２５、凹
溝２３、油孔４０、ドレンポート３９、管路４１
を経てドレンタンク２６へ排出される。また、ポ
ンプ１から吐出された圧油は逆止弁５によつて止
められ、管路４４に流入することはない。そし
て、受圧室２０内の油は油孔１９、凹溝１８、油
孔４２、凹溝２４，２３、油孔４０、ドレンポー
ト３９、管路４１をこの順に経てドレンタンク２
６に排出されるので受圧室２０内の圧力は低下
し、パイロツトスプール１３には受圧室１７に流
入した油圧のみが作用する。従つて、パイロツト
スプール１３が左行する際に受圧室１７に流入す
る圧油の圧力よりも小さい圧力が受圧室１７に作
用した場合にパイロツトスプール１３が右行する
こととなる。この結果、リフトシリンダ４の積荷
を降すことにより管路４９内の圧油の圧力が低下
すると、受圧室１７内の圧油の圧力が低下し、こ
れに伴つて、パイロツトスプール１３はばね１４
によつて押推されて右方へ移動し、パイロツトス
プール１３の右行により、受圧室２２内への圧油
が遮断されるので、バイパススプール１１もばね
１２によつて押推されて右方へ移動し、第１図の
状態に復帰する。 A situation in which the lift cylinder 4 is raised in a loaded state is shown in FIG. When the directional control valve 3 is switched to the 3a position as above, the pressure oil discharged from the pump 1 is transferred to the lift cylinder 4 as above.
However, since the lift cylinder 4 is in a loaded state, the pressure of the pressure oil in the pipe line 49 increases. This pressure oil flows through the pipe line 16 and the oil hole 48.
It flows into the pressure receiving chamber 17 through the. On the other hand, pump 2
The pressure oil discharged from the pipe 44 and the pressure oil port 4
3, oil hole 45, groove 24, oil hole 42, groove 18,
It enters the pressure receiving chamber 20 through the oil hole 19, but the pressure receiving chamber 20
Since the pressure receiving area of the pressure receiving chamber 17 is larger than the pressure receiving area of the pressure receiving chamber 17, the pilot spool 13 moves to the left against the pressing force of the spring 14 due to the pressure oil flowing into the pressure receiving chamber 17, and occupies the position shown in the figure. . Then, the pressure oil in the pressure receiving chamber 17 flows into the pressure receiving chamber 22 through the oil hole 21 and the groove 37, and as shown in FIG. 3, the bypass spool 11 is moved to the left against the spring 12. . As a result, the groove 24 and the groove 23 communicate with each other, so that the pressure oil discharged from the pump 2 is transferred to the pipe line 4.
4, pressure oil port 43, oil hole 45, groove 24, 2
3. The oil is discharged into the drain tank 26 through the oil hole 40, drain port 39, and pipe line 41 in this order. In this way, the pressure oil supplied to the lift cylinder 4 is only the pressure oil discharged from the pump 1, and the lift cylinder 4 rises at a low speed. Note that as the pilot spool 13 moves to the left and the bypass spool 11 moves to the left, the oil in the chambers 46 and 47 flows through the oil hole 25, the groove 23, the oil hole 40, the drain port 39, and the pipe line 41.
The water is discharged to the drain tank 26 through . Moreover, the pressure oil discharged from the pump 1 is stopped by the check valve 5 and does not flow into the pipe line 44. The oil in the pressure receiving chamber 20 passes through the oil hole 19, the groove 18, the oil hole 42, the grooves 24, 23, the oil hole 40, the drain port 39, and the pipe line 41 in this order, and then goes to the drain tank 2.
6, the pressure inside the pressure receiving chamber 20 decreases, and only the hydraulic pressure flowing into the pressure receiving chamber 17 acts on the pilot spool 13. Therefore, if a pressure smaller than the pressure of the pressure oil flowing into the pressure receiving chamber 17 acts on the pressure receiving chamber 17 when the pilot spool 13 moves leftward, the pilot spool 13 moves rightward. As a result, when the pressure of the pressure oil in the pipe line 49 decreases due to the unloading of the lift cylinder 4, the pressure of the pressure oil in the pressure receiving chamber 17 decreases, and accordingly, the pilot spool 13
As the pilot spool 13 moves to the right, pressure oil to the pressure receiving chamber 22 is cut off, and the bypass spool 11 is also pushed by the spring 12 and moves to the right. , and returns to the state shown in FIG.
リフトシリンダ４を下降させる場合には、方向
切換弁３を３ｃ位置に切り換える。すると、ポン
プ１，２から吐出された圧油は管路４９から方向
切換弁３、管路５２を経てドレンタンク２６へ流
出し、リフトシリンダ４の押側室内の油も管路５
１、方向切換弁３、管路５２を経てドレンタンク
２６へ排出される。 When lowering the lift cylinder 4, the directional control valve 3 is switched to the 3c position. Then, the pressure oil discharged from the pumps 1 and 2 flows from the pipe 49 through the directional control valve 3 and the pipe 52 to the drain tank 26, and the oil in the push side chamber of the lift cylinder 4 also flows into the pipe 5.
1. It is discharged to the drain tank 26 via the directional switching valve 3 and the pipe 52.
上記実施例では２個のポンプ１，２から吐出さ
れた圧油を１個の速度切換弁７で合流させるよう
にしたが、２個以上のポンプから吐出された圧油
を２個以上の速度切換弁により合流させることも
可能であり、この場合は速度切換弁の設定圧力を
変えることにより３段階以上の速度切換が可能と
なる。 In the above embodiment, the pressure oil discharged from the two pumps 1 and 2 is combined at one speed switching valve 7, but the pressure oil discharged from two or more pumps is combined at two or more speeds. It is also possible to merge them using a switching valve, and in this case, by changing the set pressure of the speed switching valve, it becomes possible to switch the speed in three or more stages.
（考案の効果）
本考案においては、１のポンプから吐出された
圧油を他のポンプからアクチユエータに至る圧油
供給路に合流させるか又は上記他のポンプからの
圧油のみをタンクにバイパスさせるかを選択的に
切り換えるバイパススプールと、このバイパスス
プールを駆動するパイロツトスプールとを具え、
上記パイロツトスプールの片側に上記圧油供給路
内の圧油が作用する第１の受圧室を形成するとと
もに、他側に上記１のポンプから吐出された圧油
が作用する上記第１の受圧室の受圧面積より小さ
い受圧面積を有する第２の受圧室を形成し、上記
パイロツトスプールには、上記第１の受圧室とバ
イパススプールの受圧室との間の連通路を開閉す
るランド部を形成したので、アクチユエータの負
荷が小さいときは、第１の受圧室内の圧油の圧力
が低く、従つて、パイロツトスプールが切り換わ
らないので、バイパススプールは駆動されず、こ
の結果、１のポンプから吐出された圧油は他のポ
ンプからアクチユエータに至る圧油供給路に合流
してアクチユエータに供給されるので、アクチユ
エータは高速で駆動される。(Effect of the invention) In the invention, the pressure oil discharged from one pump is merged into the pressure oil supply path from the other pump to the actuator, or only the pressure oil from the other pump is bypassed to the tank. It is equipped with a bypass spool that selectively switches between the two, and a pilot spool that drives this bypass spool.
A first pressure receiving chamber is formed on one side of the pilot spool on which pressure oil in the pressure oil supply path acts, and the first pressure receiving chamber on the other side is acted on by pressure oil discharged from the first pump. A second pressure receiving chamber having a pressure receiving area smaller than the pressure receiving area of is formed, and a land portion is formed on the pilot spool to open and close a communication path between the first pressure receiving chamber and the pressure receiving chamber of the bypass spool. Therefore, when the load on the actuator is small, the pressure of the pressure oil in the first pressure receiving chamber is low, and therefore the pilot spool does not switch, so the bypass spool is not driven, and as a result, no fluid is discharged from the first pump. The actuator is driven at high speed because the pressurized oil flows into the pressure oil supply path from the other pump to the actuator and is supplied to the actuator.
アクチユエータの負荷が大きいときは、第１の
受圧室内の圧油の圧力が上昇するので、パイロツ
トスプールが切り換り、これによつてバイパスス
プールが駆動される結果、１のポンプから吐出さ
れた圧油はタンクにバイパスされ、アクチユエー
タには他のポンプから吐出された圧油のみが供給
され、アクチユエータは低速で駆動される。 When the load on the actuator is large, the pressure of the pressure oil in the first pressure receiving chamber increases, so the pilot spool is switched, which drives the bypass spool, and as a result, the pressure discharged from the first pump increases. The oil is bypassed to the tank, and the actuator is supplied only with pressure oil discharged from other pumps, and the actuator is driven at low speed.
また、第２の受圧室内の圧力がバイパススプー
ルの切り換えと同時に低下する。従つて、パイロ
ツトスプールがその片側に向つて移動する場合
と、他側に向つて移動する場合とでは、第１の受
圧室内の圧油の圧力に差が出るため、パイロツト
スプールの不安定な動きが抑止される。従つて、
第１の受圧室に作用する圧油の圧力がパイロツト
スプールの切り換え圧力に近接した場合にも、パ
イロツトスプールは切り換わらず、この結果、バ
イパススプールも切り換わらないため、アクチユ
エータの駆動速度が高速になつたり低速になつた
りすることはない。 Further, the pressure in the second pressure receiving chamber decreases at the same time as the bypass spool is switched. Therefore, when the pilot spool moves toward one side and when it moves toward the other side, there is a difference in the pressure of the pressure oil in the first pressure receiving chamber, resulting in unstable movement of the pilot spool. is suppressed. Therefore,
Even when the pressure of the pressure oil acting on the first pressure receiving chamber approaches the switching pressure of the pilot spool, the pilot spool does not switch, and as a result, the bypass spool also does not switch, so the actuator drive speed increases. It doesn't get slower or slower.
第１図ないし第３図は本考案の１実施例の１部
を破断して示す油圧回路図で、第１図はアクチユ
エータの負荷が小さい場合、第２図及び第３図は
アクチユエータの負荷が大きい場合を示す。第４
図は従来装置の油圧回路図である。
ポンプ……１，２、アクチユエータ……４、圧
油供給路……４９、バイパススプール……１１、
パイロツトスプール……１３、タンク……２６、
第１の受圧室……１７、第２の受圧室……２０。
1 to 3 are partially cutaway hydraulic circuit diagrams of an embodiment of the present invention. FIG. 1 shows a case where the load on the actuator is small, and FIGS. 2 and 3 show a case where the load on the actuator is small. Indicates a large case. Fourth
The figure is a hydraulic circuit diagram of a conventional device. Pump...1, 2, Actuator...4, Pressure oil supply line...49, Bypass spool...11,
Pilot spool...13, tank...26,
First pressure receiving chamber...17, second pressure receiving chamber...20.
Claims (1)
流させてアクチユエータに供給することによりア
クチユエータの駆動速度を切り換えるようにした
油圧駆動装置における駆動速度切換装置におい
て、１のポンプから吐出された圧油を他のポンプ
からアクチユエータに至る圧油供給路に合流させ
るか又は上記他のポンプからの圧油のみをタンク
にバイパスさせるかを選択的に切り換えるバイパ
ススプールと、このバイパススプールを駆動する
パイロツトスプールとを具え、上記パイロツトス
プールの片側に上記圧油供給路内に圧油が作用す
る第１の受圧室を形成するとともに、他側に上記
１のポンプから吐出された圧油が作用する上記第
１の受圧室の受圧面積より小さい受圧面積を有す
る第２の受圧室を形成し、上記パイロツトスプー
ルを上記第１の受圧室の方向に所定の圧力で押圧
するばねを設け、上記パイロツトスプールの外周
に上記第１の受圧室とバイパススプールの受圧室
との間の連通路を開閉するランド部を形成したこ
とを特徴とする油圧駆動装置における駆動速度切
換装置。 In a drive speed switching device for a hydraulic drive device, which switches the drive speed of an actuator by dividing or merging the pressure oil discharged from a plurality of pumps and supplying the same to the actuator, the pressure oil discharged from one pump is A bypass spool that selectively switches whether to join the pressure oil supply path from another pump to the actuator or bypass only the pressure oil from the other pump to the tank, and a pilot spool that drives this bypass spool. A first pressure receiving chamber is formed on one side of the pilot spool on which pressure oil acts in the pressure oil supply path, and a first pressure receiving chamber is formed on the other side on which pressure oil discharged from the first pump acts. A second pressure receiving chamber is formed having a pressure receiving area smaller than the pressure receiving area of the pressure receiving chamber, and a spring is provided for pressing the pilot spool in the direction of the first pressure receiving chamber with a predetermined pressure, and the spring is provided on the outer periphery of the pilot spool. 1. A drive speed switching device for a hydraulic drive device, characterized in that a land portion is formed to open and close a communication path between a first pressure receiving chamber and a pressure receiving chamber of a bypass spool.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1984171636U JPH0346246Y2 (en) | 1984-11-14 | 1984-11-14 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1984171636U JPH0346246Y2 (en) | 1984-11-14 | 1984-11-14 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6187203U JPS6187203U (en) | 1986-06-07 |
| JPH0346246Y2 true JPH0346246Y2 (en) | 1991-09-30 |
Family
ID=30729312
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1984171636U Expired JPH0346246Y2 (en) | 1984-11-14 | 1984-11-14 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0346246Y2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5421793B2 (en) * | 1972-08-18 | 1979-08-02 | ||
| JPS5743002A (en) * | 1980-08-28 | 1982-03-10 | Kayaba Ind Co Ltd | Automatic speed changeover valve for two-speed motor |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6220732Y2 (en) * | 1977-07-15 | 1987-05-27 | ||
| JPS58125701U (en) * | 1982-02-19 | 1983-08-26 | カヤバ工業株式会社 | hydraulic distribution device |
-
1984
- 1984-11-14 JP JP1984171636U patent/JPH0346246Y2/ja not_active Expired
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5421793B2 (en) * | 1972-08-18 | 1979-08-02 | ||
| JPS5743002A (en) * | 1980-08-28 | 1982-03-10 | Kayaba Ind Co Ltd | Automatic speed changeover valve for two-speed motor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6187203U (en) | 1986-06-07 |
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