JP2724888B2 - Control circuit of variable displacement hydraulic motor - Google Patents
Control circuit of variable displacement hydraulic motorInfo
- Publication number
- JP2724888B2 JP2724888B2 JP1253166A JP25316689A JP2724888B2 JP 2724888 B2 JP2724888 B2 JP 2724888B2 JP 1253166 A JP1253166 A JP 1253166A JP 25316689 A JP25316689 A JP 25316689A JP 2724888 B2 JP2724888 B2 JP 2724888B2
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- hydraulic motor
- control
- valve
- hydraulic
- 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 - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/42—Control of exclusively fluid gearing hydrostatic involving adjustment of a pump or motor with adjustable output or capacity
- F16H61/423—Motor capacity control by fluid pressure control means
Landscapes
- Operation Control Of Excavators (AREA)
- Fluid-Pressure Circuits (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、例えば油圧ショベル等の建設機械に設けら
れ、走行用油圧モータを駆動制御するのに用いて好適な
可変容量型油圧モータの制御回路に関する。The present invention relates to control of a variable displacement hydraulic motor which is provided in a construction machine such as a hydraulic shovel and is preferably used to drive and control a traveling hydraulic motor. Circuit.
第４図に従来技術による可変容量型油圧モータの制御
回路を示す。FIG. 4 shows a control circuit of a conventional variable displacement hydraulic motor.
図において、１は車両等の慣性体２を駆動する走行用
油圧モータとしての可変容量型の油圧モータを示し、該
油圧モータ１は容量可変部1Aを有し、該容量可変部1Aを
傾転駆動することによってモータ容量が大容量と小容量
とに可変に設定される。３は油圧モータ１に付設された
容量可変アクチュエータ、４は該アクチュエータ３に供
給する圧油を切換制御する容量制御弁を示し、該容量制
御弁４は油圧パイロット式の切換弁によって構成され、
油圧パイロット部4Aに供給されるパイロット圧に応じて
小容量位置（イ）と大容量位置（ロ）とに切換えられ
る。そして、該容量制御弁４は小容量位置（イ）で後述
するシャトル弁18からの油圧によりアクチュエータ３を
矢示Ａ方向に変位させ、油圧モータ１の容量可変部1Aを
小容量側に傾転させ、大容量位置（ロ）に切換えられた
ときには、シャトル弁18からの圧油によりアクチュエー
タ３を矢印Ｂ方向に変位させ、容量可変部1Aを大容量側
に傾転させるようになっている。In FIG. 1, reference numeral 1 denotes a variable displacement hydraulic motor as a traveling hydraulic motor for driving an inertial body 2 such as a vehicle. The hydraulic motor 1 has a variable displacement unit 1A, and tilts the variable displacement unit 1A. By driving, the motor capacity is variably set to a large capacity and a small capacity. Reference numeral 3 denotes a variable displacement actuator attached to the hydraulic motor 1, reference numeral 4 denotes a displacement control valve for switching control of the pressure oil supplied to the actuator 3, and the displacement control valve 4 is constituted by a hydraulic pilot type switching valve.
The position is switched between the small capacity position (a) and the large capacity position (b) according to the pilot pressure supplied to the hydraulic pilot unit 4A. Then, the displacement control valve 4 displaces the actuator 3 in the direction of arrow A by hydraulic pressure from a shuttle valve 18 described later at the small displacement position (a), and tilts the displacement variable portion 1A of the hydraulic motor 1 to the small displacement side. Then, when the position is switched to the large capacity position (b), the actuator 3 is displaced in the direction of arrow B by the pressure oil from the shuttle valve 18 to tilt the variable capacity portion 1A to the large capacity side.
５はタンク６と共に主油圧源を構成する油圧ポンプ、
7A,7Bは該油圧ポンプ5,タンク６を油圧モータ１に接続
した一対の主管路、８は該主管路7A,7Bの途中に設けた
方向切換弁を示し、該方向切換弁８は操作レバー8Aによ
って中立位置（イ）から左，右の切換位置（ロ），
（ハ）に切換えられ、切換位置（ロ），（ハ）で油圧モ
ータ１を矢示C,D方向に回転させるようになっている。
また、該方向切換弁８はノーマルオープン型が採用さ
れ、中立位置（イ）で主管路7A,7B内が負圧となったと
きに、タンク６内の作動油を主管路7A,7B内に補給でき
るようになっている。5 is a hydraulic pump that constitutes a main hydraulic power source together with the tank 6,
7A and 7B are a pair of main lines connecting the hydraulic pump 5 and the tank 6 to the hydraulic motor 1, 8 is a direction switching valve provided in the middle of the main lines 7A and 7B, and the direction switching valve 8 is an operating lever. 8A, left and right switching position (b) from neutral position (b),
The hydraulic motor 1 is switched in the directions C and D at the switching positions (B) and (C).
The direction switching valve 8 is of a normally open type, and when the pressure in the main pipelines 7A and 7B becomes negative at the neutral position (a), the hydraulic oil in the tank 6 flows into the main pipelines 7A and 7B. It can be replenished.
９は油圧モータ１と方向切換弁８との間に位置して、
主管路7A,7Bの途中に設けられたカウンタバランス弁を
示し、該カウンタバランス弁９は、一対の逆止弁10A,10
Bと、該逆止弁10A,10Bと並列に設けられ、常時はばね11
A,11Bによって閉弁状態におかれ、油圧ポンプ５からの
高圧がシャトル弁12を介して作用するときにばね11A,11
Bに抗して開弁される一対の切換弁13A,13Bと、該切換弁
13A,13Bの開，閉弁速度を調整する絞り14A,14Bとから大
略構成され、切換弁13A,13Bは油圧モータ１からも戻り
油をタンク６側に主管路7A,7Bを介して排出させるよう
になっている。そして、該カウンタバランス弁９は油圧
モータ１が慣性体２によって慣性回転するときに切換弁
13A,13Bを閉弁させ、車両が坂道等で逸走するのを防止
するようになっている。9 is located between the hydraulic motor 1 and the direction switching valve 8,
It shows a counterbalance valve provided in the middle of the main pipelines 7A and 7B, and the counterbalance valve 9 includes a pair of check valves 10A and 10A.
B and the check valves 10A and 10B are provided in parallel with each other.
When the high pressure from the hydraulic pump 5 acts via the shuttle valve 12, the springs 11A and 11B are closed.
B, a pair of switching valves 13A and 13B opened against
The switching valves 13A and 13B are mainly composed of throttles 14A and 14B for adjusting the opening and closing speeds of the valves 13A and 13B. The switching valves 13A and 13B discharge the return oil from the hydraulic motor 1 to the tank 6 via the main pipelines 7A and 7B. It has become. The counterbalance valve 9 is a switching valve when the hydraulic motor 1 is inertially rotated by the inertial body 2.
The valves 13A and 13B are closed to prevent the vehicle from running off on a slope or the like.
15はタンク６と共に副油圧源を構成するパイロットポ
ンプ、16は該パイロットポンプ15と容量制御弁４の油圧
パイロット部4Aとを接続した制御管路、17は該制御管路
16の途中に設けられた圧力制御弁としての電磁比例減圧
弁を示し、該減圧弁17はソレノイド部17Aに外部から給
電される信号の電圧値等に比例してその設定圧が変化
し、制御管路16内のパイロット圧をこの設定圧に応じて
減圧制御するようになっている。そして、該減圧弁17は
制御管路16内のパイロット圧を容量制御弁４の切換圧PA
の前，後で多段階に制御することにより、容量制御弁４
を小容量位置（イ）と大容量位置（ロ）とに切換えるよ
うになっている（第２図参照）。Reference numeral 15 denotes a pilot pump which constitutes a sub-hydraulic power source together with the tank 6, 16 denotes a control line connecting the pilot pump 15 and a hydraulic pilot unit 4A of the capacity control valve 4, and 17 denotes a control line.
16 shows an electromagnetic proportional pressure reducing valve as a pressure control valve provided in the middle of 16; the pressure reducing valve 17 changes its set pressure in proportion to the voltage value of a signal supplied from the outside to the solenoid 17A, The pilot pressure in the pipeline 16 is controlled to be reduced according to the set pressure. The pressure reducing valve 17 changes the pilot pressure in the control line 16 to the switching pressure P A of the capacity control valve 4.
Before and after the multi-stage control, the capacity control valve 4
Is switched between a small capacity position (a) and a large capacity position (b) (see FIG. 2).
18は油圧モータ１とカウンタバランス弁９との間に位
置して主管路7A,7B間に設けられた高圧選択弁としての
シャトル弁を示し、該シャトル弁18は主管路7A,7Bのう
ち高圧側の圧油を選択して、この圧油を容量制御弁４を
介してアクチュエータ３に供給するようになっている。
さらに、19A,19Bはオーバロードリリーフ弁を示してい
る。Reference numeral 18 denotes a shuttle valve located between the hydraulic motor 1 and the counterbalance valve 9 and provided as a high-pressure selection valve provided between the main lines 7A and 7B. The shuttle valve 18 is a high-pressure selection valve of the main lines 7A and 7B. The pressure oil on the side is selected, and this pressure oil is supplied to the actuator 3 via the capacity control valve 4.
Further, 19A and 19B indicate overload relief valves.
このように構成される油圧モータ１の制御回路では、
例えば方向切換弁８を中立位置（イ）から切換位置
（ロ）に切換えた場合、油圧ポンプ５からの圧油は主管
路7A,カウンタバランス弁９の逆止弁10A等を介して油圧
モータ１に給排され、該油圧モータ１を慣性体２と共に
矢示Ｃ方向に回転させる。そして、カウンタバランス弁
９の切換弁13A,13Bは油圧ポンプ５からの高圧によりば
ね11A,11Bに抗して開弁するので、油圧モータ１からの
戻り油は主管路7B,切換弁13Bを介してタンク６へと排出
される。また、方向切換弁８を中立位置（イ）から切換
位置（ハ）に切換えた場合には、油圧モータ１は矢示Ｄ
方向に回転する。In the control circuit of the hydraulic motor 1 configured as described above,
For example, when the direction switching valve 8 is switched from the neutral position (a) to the switching position (b), the hydraulic oil from the hydraulic pump 5 receives the hydraulic motor 1 via the main line 7A, the check valve 10A of the counterbalance valve 9, and the like. To rotate the hydraulic motor 1 together with the inertial body 2 in the direction of arrow C. Since the switching valves 13A and 13B of the counter balance valve 9 open against the springs 11A and 11B due to the high pressure from the hydraulic pump 5, the return oil from the hydraulic motor 1 passes through the main line 7B and the switching valve 13B. And discharged to the tank 6. When the direction switching valve 8 is switched from the neutral position (a) to the switching position (c), the hydraulic motor 1
Rotate in the direction.
一方、平地走行時等の車両にかかる負荷が小さい状態
で、油圧モータ１を高速回転させたい場合には、制御管
路16内のパイロット圧を減圧弁17によって容量制御弁４
の切換圧PAよりも低い圧力に設定すれば、該容量制御弁
４は図示の小容量位置（イ）に切換えられ、アクチュエ
ータ３を矢示Ａ方向に変位させることにより、油圧モー
タ１の容量可変部1Aを小容量側に傾転させ、モータ容量
を小容量とすることによって、油圧モータ１を小トルク
で高速回転させ、車両を高速で走行させることができ
る。On the other hand, when it is desired to rotate the hydraulic motor 1 at a high speed while the load on the vehicle is small, such as when traveling on level ground, the pilot pressure in the control line 16 is reduced by the pressure reducing valve 17 to the capacity control valve 4.
Is set to a pressure lower than the switching pressure P A of the capacitive control valve 4 is switched to the small volume position shown (i), by displacing the actuator 3 in the direction of arrow A, the capacity of the hydraulic motor 1 By tilting the variable portion 1A to the small capacity side and making the motor capacity small, the hydraulic motor 1 can be rotated at high speed with small torque and the vehicle can run at high speed.
また、登坂時等の車両にかかる負荷が大きい状態で、
油圧モータ１の駆動トルクを増大させたい場合には、減
圧弁17のソレノイド部17Aに給電する電圧を高くするこ
とによって、制御管路16内のパイロット圧を容量制御弁
４の切換圧PAよりも高い圧力に設定すれば、該容量制御
弁４は大容量位置（ロ）に切換えられ、アクチュエータ
３を矢示Ｂ方向に変位させて、容量可変部1Aを大容量側
に傾転させ、これによって、モータ容量を大容量とし、
油圧モータ１を大トルクで低速回転させることができ、
車両の登坂力等を高めることができる。Also, when the load on the vehicle is large, such as when climbing a hill,
If you want to increase the driving torque of the hydraulic motor 1, by increasing the voltage to power the solenoid portion 17A of the pressure reducing valve 17, the pilot pressure of the control line 16 from the switching pressure P A of the displacement control valve 4 If the pressure is also set to a high pressure, the displacement control valve 4 is switched to the large displacement position (b), the actuator 3 is displaced in the direction of arrow B, and the displacement variable portion 1A is tilted to the large displacement side. With this, the motor capacity is increased,
The hydraulic motor 1 can be rotated at a low speed with a large torque,
The hill climbing power of the vehicle can be increased.
そして、例えば方向切換弁８を切換位置（ロ）に切換
え、油圧ポンプ５からの圧油により油圧モータ１が矢示
Ｃ方向に回転している状態で、車両を停止させようとす
る場合または坂道を降坂する場合等に、油圧モータ１が
慣性体２によって矢示Ｃ方向に慣性回転すると、主管路
7A内の圧力が低下して、カウンタバランス弁９の切換弁
13A,13Bにシャトル弁12を介して作用する圧力も低下す
るから、切換弁13Bはばね11Bによって図示の如く閉弁さ
れ、油圧モータ１からの戻り油は切換弁13Bとの間で主
管路7B内に封じ込められるようになり、これによって、
主管路7B内にブレーキ圧を発生させて、車両を停止させ
たり、降坂時の逸走を抑えたりすることができるように
なっている。Then, for example, when the direction switching valve 8 is switched to the switching position (b) and the vehicle is to be stopped in a state where the hydraulic motor 1 is rotating in the direction of arrow C by the hydraulic oil from the hydraulic pump 5, or when the vehicle is on a slope. When the hydraulic motor 1 is inertially rotated in the direction of arrow C by the inertia body 2 when descending a slope, the main pipeline
When the pressure in 7A drops, the switching valve of the counterbalance valve 9
Since the pressure acting on the shuttle valves 12A and 13B via the shuttle valve 12 also decreases, the switching valve 13B is closed as shown by the spring 11B, and the return oil from the hydraulic motor 1 returns to the main pipeline 7B between the switching motor 13B and the switching valve 13B. That will be contained within
By generating a brake pressure in the main pipeline 7B, it is possible to stop the vehicle and suppress runaway when going down a slope.
ところで、上述した従来技術では、カウンタバランス
弁９に一対の絞り14A,14Bを設け、該絞り14A,14Bによっ
て切換弁13A,13Bの開，閉弁速度を調整するようにして
いるものの、切換弁13A,13Bの閉弁速度を早くした場合
には、車両の停止時、降坂時等に油圧モータ１が慣性回
転するようになると、例えば切換弁13Bによって主管路7
Bが急激に遮断され、切換弁13Bの閉弁時の衝撃が大きく
なり、逆に閉弁速度を遅くした場合には、例えば油圧モ
ータ１が矢示Ｃ方向に慣性回転を続けて、圧油（戻り
油）が主管路7B側に多量に排出され、主管路7A側の作動
油が不足して、負圧が発生し易くなり、キャビテーショ
ンを発生させるという問題がある。By the way, in the prior art described above, a pair of throttles 14A and 14B are provided in the counter balance valve 9, and the opening and closing speeds of the switching valves 13A and 13B are adjusted by the throttles 14A and 14B. When the valve closing speeds of the valves 13A and 13B are increased, when the hydraulic motor 1 is rotated by inertia when the vehicle is stopped or when the vehicle descends a slope, for example, the switching valve 13B causes the main pipeline 7 to be closed.
When the valve B is suddenly shut off and the impact when the switching valve 13B closes becomes large and the valve closing speed is slowed down, for example, the hydraulic motor 1 continues the inertial rotation in the direction of arrow C, and the hydraulic oil A large amount of (return oil) is discharged to the side of the main line 7B, and there is a shortage of hydraulic oil on the side of the main line 7A, so that a negative pressure is likely to be generated, and cavitation is generated.
本発明は上述した従来技術の問題に鑑みなされたもの
で、本発明は油圧モータの慣性回転時にキャビテーショ
ンが発生するのを効果的に防止することができ、例えば
車両停止時等の衝撃を確実に低減でき、信頼性を向上で
きるようにした可変容量型油圧モータの制御回路を提供
するものである。The present invention has been made in view of the above-described problems of the related art, and the present invention can effectively prevent cavitation from occurring during inertial rotation of a hydraulic motor, and can reliably prevent impact when, for example, a vehicle stops. An object of the present invention is to provide a control circuit for a variable displacement hydraulic motor that can reduce the power consumption and improve the reliability.
上述した課題を解決するために本発明は採用する構成
の特徴は、制御管路に圧力制御弁と容量制御弁の油圧パ
イロット部との間に位置して補助管路の一端側を接続
し、該補助管路の他端側を油圧モータとカウンタバラン
ス弁との間で各主管路に一対の逆流防止手段を介して接
続したことにある。In order to solve the above-described problem, the present invention employs a configuration characterized by connecting one end of an auxiliary pipeline located between a pressure control valve and a hydraulic pilot portion of a capacity control valve to a control pipeline, The other end of the auxiliary line is connected to each main line between the hydraulic motor and the counterbalance valve via a pair of backflow prevention means.
また、前記圧力制御弁は制御管路内の圧力をタンク圧
よりも高い圧力で少なくとのも二段階に制御し、これに
よって前記容量制御弁を大容量位置と小容量位置とに切
換えるようにするのがよい。そして、前記容量制御弁は
制御管路内の圧力が所定圧より高くなると大容量位置に
切換わり、所定圧より低くなると小容量位置に切換わる
構成とするのが好ましい。Further, the pressure control valve controls the pressure in the control line at a pressure higher than the tank pressure in at least two stages, thereby switching the capacity control valve between a large capacity position and a small capacity position. Good to do. Preferably, the displacement control valve switches to a large displacement position when the pressure in the control line is higher than a predetermined pressure, and switches to a small displacement position when the pressure in the control pipeline is lower than the predetermined pressure.
さらに、前記制御管路の途中には補助管路の接続点と
副油圧源との間に位置して流量制御手段を設けるのが好
ましい。Further, it is preferable that a flow control means is provided in the middle of the control line between the connection point of the auxiliary line and the auxiliary hydraulic source.
上記構成により、油圧モータの慣性回転時に一対の主
管路のうち一方の主管路に作動油不足が生じたとして
も、この主管路に制御管路内の圧油を補助管路，逆流防
止手段を介して補給することができ、作動油不足を解消
できる。また、制御管路からの高い圧力で容量制御弁を
大容量位置に切換えた場合、油圧モータの慣性回転時に
制御管路内の圧油が主管路側に補給されると、制御管路
内の圧力が低下し、容量制御弁を小容量位置に自動的に
切換えることができる。With this configuration, even if one of the pair of main lines becomes short of hydraulic oil during the inertial rotation of the hydraulic motor, the main line is provided with the auxiliary oil and the backflow prevention means by the pressure oil in the control line. Replenishment via hydraulic fluid, and the shortage of hydraulic oil can be eliminated. Also, when the displacement control valve is switched to the large displacement position with a high pressure from the control line, if the pressure oil in the control line is supplied to the main line side during the inertial rotation of the hydraulic motor, the pressure in the control line is reduced. And the displacement control valve can be automatically switched to the small displacement position.
以下、本発明の実施例を第１図ないし第３図に基づい
て説明する。なお、実施例では前述した第４図に示す従
来技術と同一の構成要素に同一の符号を付し、その説明
を省略するものとする。Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3. In the embodiment, the same components as those in the prior art shown in FIG. 4 described above are denoted by the same reference numerals, and description thereof will be omitted.
而して、第１図および第２図は本発明の第１の実施例
を示している。FIGS. 1 and 2 show a first embodiment of the present invention.
図中、21は制御管路16の途中に設けられた圧力制御弁
としての電磁比例減圧弁を示し、該減圧弁21は従来技術
で述べた減圧弁17とほぼ同様にソレノイド部21Aを有
し、該ソレノイド部21Aに給電される電圧値に比例して
制御管路16内のパイロット圧を減圧制御しているもの
の、該減圧弁21はこのパイロット圧を第２図に示す如く
タンク圧よりも高い最低圧PB以上の圧力で制御するよう
になっている。そして、該減圧弁21により制御管路16内
のパイロット圧を圧力PC程度に設定した場合には、この
圧力PCは容量制御弁４の切換圧PAよりも高いから、該容
量制御弁４は小容量位置（イ）から大容量位置（ロ）に
切換えられ、油圧モータ１をアクチュエータ３を、介し
て大容量に設定でき、大トルクで低速回転させることが
できる。In the figure, reference numeral 21 denotes an electromagnetic proportional pressure reducing valve as a pressure control valve provided in the middle of the control line 16, and the pressure reducing valve 21 has a solenoid portion 21A almost similarly to the pressure reducing valve 17 described in the related art. Although the pilot pressure in the control line 16 is controlled to decrease in proportion to the voltage supplied to the solenoid 21A, the pressure reducing valve 21 reduces the pilot pressure to a value lower than the tank pressure as shown in FIG. and controls with high minimum pressure P B over pressure. Then, in the case of setting the pilot pressure of the control line 16 to approximately the pressure P C by the pressure reducing valve 21, the pressure P C is from greater than switching pressure P A of the displacement control valve 4, the capacitive control valve 4 is switched from the small capacity position (a) to the large capacity position (b), the hydraulic motor 1 can be set to a large capacity via the actuator 3, and can be rotated at a low speed with a large torque.
22は一端側が容量制御弁４の油圧パイロット部4Aと減
圧弁21との間に位置して制御管路16に接続点23で接続さ
れた補助管路を示し、該補助管路22の他端側は油圧モー
タ１とカウンタバランス弁９との間で主管路7A,7Bに一
対の逆流防止手段としての逆止弁24A,24Bを介して接続
されている。そして、該補助管路22は主管路7A,7B内の
圧力が減圧弁21の設定圧よりも低下したときに、制御管
路16内の圧油を主管路7A,7Bに逆止弁24A,24Bを介して流
入（補給）させ、逆向きの流れを逆止弁24A,24Bによっ
て阻止させるようになっている。Reference numeral 22 denotes an auxiliary pipe whose one end is located between the hydraulic pilot section 4A of the capacity control valve 4 and the pressure reducing valve 21 and is connected to the control pipe 16 at a connection point 23. The side is connected to the main pipelines 7A and 7B between the hydraulic motor 1 and the counterbalance valve 9 via a pair of check valves 24A and 24B as a backflow prevention means. When the pressure in the main pipelines 7A and 7B falls below the set pressure of the pressure-reducing valve 21, the auxiliary pipeline 22 transfers the pressure oil in the control pipeline 16 to the main pipelines 7A and 7B by a check valve 24A, The air is supplied (supplied) through the inlet 24B, and the reverse flow is stopped by the check valves 24A and 24B.
さらに、25は減圧弁21と補助管路22の接続点23との間
に位置して制御管路16の途中に設けた流量制御手段とし
ての絞り通路を示し、該絞り通路25は制御管路16内の圧
油が補助管路22、逆止弁24A,24Bを介して主管路7A,7B側
に補給されるときに、制御管路16内のパイロット圧をそ
の絞り作用によって低下させ、例えば容量制御弁４を大
容量位置（ロ）から小容量位置（イ）へと自動的に切換
えさせるようになっている。Further, reference numeral 25 denotes a throttle passage as flow control means provided between the pressure reducing valve 21 and the connection point 23 of the auxiliary pipeline 22 and provided in the middle of the control pipeline 16, and the throttle passage 25 is a control pipeline. When the pressure oil in 16 is supplied to the main pipelines 7A and 7B via the auxiliary pipeline 22 and the check valves 24A and 24B, the pilot pressure in the control pipeline 16 is reduced by the throttle action, for example, The capacity control valve 4 is automatically switched from the large capacity position (b) to the small capacity position (a).
本実施例による油圧モータ１の制御回路は上述の如き
構成を有するもので、その基本的な作動については従来
技術によるものと格別差異はない。The control circuit of the hydraulic motor 1 according to the present embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.
然るに本実施例では、補助管路22の一端側を接続点23
の位置で制御管路16と接続し、補助管路22の他端側を逆
止弁24A,24Bを介して油圧モータ１の前，後で主管路7A,
7Bと接続したから、例えば油圧モータ１が矢示Ｃ方向に
回転している状態で車両を停止させるとき、または坂道
を降坂するとき等に、油圧モータ１が慣性体２によって
矢示Ｃ方向に慣性回転し、油圧モータ１からの圧油（戻
り油）が主管路7B側に多量に排出されて、主管路7A側の
圧力が低下した場合には、パイロットポンプ15からの圧
油を減圧弁21,制御管路16,補助管路22,逆止弁24Aを介し
て主管路7A側に比較的高い圧力で補給することができ、
主管路7A内に負圧が発生するのを抑えて、キャビテーシ
ョンの発生を確実に防止することができる。However, in this embodiment, one end of the auxiliary pipeline 22 is connected to the connection point 23.
And the other end of the auxiliary line 22 is connected before and after the hydraulic motor 1 via non-return valves 24A and 24B.
7B, when the vehicle is stopped while the hydraulic motor 1 is rotating in the direction of arrow C, or when the vehicle descends on a slope, the hydraulic motor 1 is moved by the inertia body 2 in the direction of arrow C. When the pressure oil (return oil) from the hydraulic motor 1 is largely discharged to the main line 7B side and the pressure on the main line 7A side is reduced, the pressure oil from the pilot pump 15 is reduced. A relatively high pressure can be supplied to the main line 7A via the valve 21, the control line 16, the auxiliary line 22, and the check valve 24A.
Generation of negative pressure in the main pipeline 7A can be suppressed, and cavitation can be reliably prevented.
従って、車両の停止時、降坂時等に油圧モータ１が慣
性回転して、カウンタバランス弁９の切換弁13A,13Bが
閉弁するときの速度を絞り14A,14Bにより比較的遅くし
ても、キャビテーションが発生するのを防止できる上
に、戻り側となっている主管路7B（7A）が切換弁13B（1
3A）によって急激に遮断されるのを防止でき、切換弁13
B（13A）の閉弁時の衝撃を効果に低減することができ
る。Therefore, even when the hydraulic motor 1 is rotated by inertia when the vehicle is stopped or on a downhill, and the switching valves 13A and 13B of the counter balance valve 9 are closed, the throttles 14A and 14B can be used to reduce the speed relatively. Cavitation can be prevented, and the return main pipe 7B (7A) is connected to the switching valve 13B (1
3A) can be prevented from being suddenly shut off by switching valve 13
The impact at the time of closing the valve B (13A) can be effectively reduced.
また、制御管路16の途中には接続点23よりも下流側に
位置して絞り通路25を設けたから、例えば減圧弁21によ
り制御管路16内のパイロット圧を第２図中に示す圧力PC
程度に設定し、容量制御弁４を小容量位置（イ）から大
容量位置（ロ）に切換えて油圧モータ１を大容量で回転
させた場合でも、方向切換弁８を中立位置（イ）に戻し
て油圧モータ１を停止させるときには、制御管路16内の
圧油が補助管路22等を介して主管路7A（7B）側に補給さ
れ、制御管路16内のパイロット圧は絞り通路25によっ
て、第２図中に例示する圧力PCから切換圧PAより低い圧
力まで低下されるようになり、これによって、容量制御
弁４を大容量位置（ロ）から小容量位置（イ）へと自動
的に切換えることができ、油圧モータ１の容量を小容量
として該油圧モータ１を比較的スムーズに停止させるこ
とができる。Also, since the throttle passage 25 is provided in the middle of the control line 16 at a position downstream of the connection point 23, for example, the pilot pressure in the control line 16 is reduced by the pressure reducing valve 21 to the pressure P shown in FIG. C
Even when the displacement control valve 4 is switched from the small displacement position (A) to the large displacement position (B) and the hydraulic motor 1 is rotated at a large displacement, the direction switching valve 8 is set to the neutral position (A). When the hydraulic motor 1 is returned and stopped, the pressure oil in the control line 16 is supplied to the main line 7A (7B) through the auxiliary line 22 and the like, and the pilot pressure in the control line 16 is reduced to the throttle passage 25. by, come to be reduced to switching pressure P a lower pressures from the pressure P C exemplified in Figure 2, thereby, the capacity control valve 4 from the large volume position (b) to the small volume position (b) Can be automatically switched, and the hydraulic motor 1 can be stopped relatively smoothly by reducing the capacity of the hydraulic motor 1 to a small capacity.
即ち、油圧モータ１が大容量で慣性回転するときに
は、油圧モータ１から多量の戻り油が排出され、カウン
タバランス弁９の閉弁時に大きなブレーキ圧が発生し、
車両停止時の衝撃が大きくなる。これに対し、油圧モー
タ１を小容量とすれば、戻り油の流量を減少させること
ができ、ブレーキ圧の急激な上昇を抑えて停止時の衝撃
を緩和できる。また、油圧モータ１が小容量で慣性回転
するときには、戻り油の減少にともない、油圧モータ１
の吸込側の油量も自動的に減少でき、これによってもキ
ャビテーションの発生を抑えることができ、信頼性を向
上させることができる。That is, when the hydraulic motor 1 rotates with a large capacity by inertia, a large amount of return oil is discharged from the hydraulic motor 1 and a large brake pressure is generated when the counter balance valve 9 is closed.
The impact when the vehicle stops is increased. On the other hand, if the hydraulic motor 1 has a small capacity, the flow rate of the return oil can be reduced, and a sudden increase in the brake pressure can be suppressed to reduce the shock at the time of stop. Further, when the hydraulic motor 1 rotates by inertia with a small capacity, the hydraulic motor 1
The amount of oil on the suction side can also be automatically reduced, thereby also suppressing the occurrence of cavitation and improving reliability.
次に、第３図は本発明の第２の実施例を示し、本実施
例では前記第１の実施例と同一の構成要素に同一の符号
を付し、その説明を省略するものとするに、本実施例の
特徴は、制御管路16の途中に圧力制御弁としての電磁式
切換弁31を設け、ソレノイド部31Aを外部から例示する
ことにより該切換弁31を低圧位置（イ）から高圧位置
（ロ）に切換える構成としたことにある。Next, FIG. 3 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The feature of the present embodiment is that an electromagnetic switching valve 31 as a pressure control valve is provided in the middle of the control line 16, and the solenoid valve 31A is externally illustrated so that the switching valve 31 is moved from the low pressure position (a) to the high pressure position. It is configured to switch to the position (b).
ここで該切換弁31を低圧位置（イ）に切換えたときに
は、制御管路16内のパイロット圧は低圧リリーフ弁32に
よって第２図中に例示する圧力PB程度に設定され、高圧
位置（ロ）に切換えたときには、高圧リリーフ弁33によ
ってパイロット圧が圧力PC程度に設定され、これによっ
て容量制御弁４は小容量位置（イ）と大容量位置（ロ）
とに切換えられる。また、制御管路16の途中には切換弁
31と高圧リリーフ弁33の接続点34との間に位置して流量
制御手段としての絞り通路35が設けられ、該絞り通路35
は第１の実施例で述べた絞り通路25とほぼ同様に構成さ
れている。Here, when the switching valve 31 is switched to the low-pressure position (a), the pilot pressure of the control line 16 is set to about the pressure P B that illustrated in Figure 2 by the low-pressure relief valve 32, high pressure position (b when switched on), the pilot pressure is set to approximately the pressure P C by a high pressure relief valve 33, whereby the control valve 4 is large position and the small volume position (a) (ii)
Is switched to In the middle of the control line 16, a switching valve is provided.
A throttle passage 35 as flow control means is provided between the connection point 34 of the high-pressure relief valve 33 and the high-pressure relief valve 33.
Is substantially the same as the throttle passage 25 described in the first embodiment.
かくして、このように構成される本実施例でも、前記
第１の実施例とほぼ同様の作用効果を得ることができ
る。Thus, also in the present embodiment having the above-described configuration, it is possible to obtain substantially the same operation and effect as in the first embodiment.
なお、前記各実施例では、制御管路16の途中に絞り通
路25（35）を設けるものとしてのべたが、絞り通路25
（35）は必ずしも設ける必要はなく、制御管路16が十分
に長ければ、その管路抵抗によって絞り通路25（35）と
同様の作用効果を得ることが可能となる。In each of the above embodiments, the throttle passage 25 (35) is provided in the middle of the control pipe line 16.
It is not always necessary to provide (35), and if the control line 16 is sufficiently long, the same effect as the throttle passage 25 (35) can be obtained due to its line resistance.
また、前記各実施例では、減圧弁21,切換弁31を外部
からの信号で電磁制御するものとして述べたが、これに
替えて、減圧弁21,切換弁31を操作レバー等によって制
御するようにしてもよい。Further, in each of the above embodiments, the pressure reducing valve 21 and the switching valve 31 are described as being electromagnetically controlled by an external signal, but instead, the pressure reducing valve 21 and the switching valve 31 may be controlled by an operation lever or the like. It may be.
さらに、前記各実施例では、油圧モータ１を走行用油
圧モータとして用いた場合を例に挙げて説明したが、本
発明はこれに限らず、油圧モータ１を油圧ショベル等の
旋回モータ，油圧クレーン等のロープウィンチ等、種々
の機械に用いた場合にも適用できるものである。Furthermore, in each of the above embodiments, the case where the hydraulic motor 1 is used as a traveling hydraulic motor has been described as an example. However, the present invention is not limited to this, and the hydraulic motor 1 may be a swing motor such as a hydraulic shovel, a hydraulic crane, or the like. The present invention can also be applied to a case where it is used for various machines such as a rope winch.
以上詳述した通り本発明によれば、制御管路を油圧モ
ータの前，後で主管路に逆止弁を介して接続したから、
油圧モータの慣性回転時に制御管路の圧油を主管路内に
補給でき、キャビテーションの発生を確実に防止できる
上に、カウンタバランス弁の閉弁時に衝撃を小さくする
ことができる。また、油圧モータを常に小容量状態で停
止させることが可能となり、停止時の衝撃を緩和でき、
信頼性を向上させることができる等、種々の効果を奏す
る。As described in detail above, according to the present invention, since the control line is connected to the main line before and after the hydraulic motor via the check valve,
Pressure oil in the control line can be supplied into the main line during the inertial rotation of the hydraulic motor, cavitation can be reliably prevented, and the impact can be reduced when the counterbalance valve is closed. In addition, the hydraulic motor can always be stopped in a small capacity state, so that the impact at the time of stop can be reduced,
Various effects such as improvement in reliability can be obtained.
第１図および第２図は本発明の第１の実施例を示し、第
１図は油圧回路図、第２図はパイロット圧と容量制御弁
の切換位置との関係を示す特性線図、第３図は第２の実
施例を示す油圧回路図、第４図は従来技術を示す油圧回
路図である。 １……油圧モータ、1A……容量可変部、２……慣性体、
３……容量可変アクチュエータ、４……容量制御弁、4A
……油圧パイロット部、５……油圧ポンプ、６……タン
ク、7A,7B……主管路、８……方向切換弁、９……カウ
ンタバランス弁、15……パイロットポンプ、16……制御
管路、21……減圧弁（圧力制御弁）、22……補助管路、
24A,24B……逆止弁（逆流防止手段）、25,35……絞り通
路、31……切換弁（圧力制御弁）、32……低圧リリーフ
弁、33……高圧リリーフ弁。1 and 2 show a first embodiment of the present invention, FIG. 1 is a hydraulic circuit diagram, FIG. 2 is a characteristic diagram showing a relationship between pilot pressure and a switching position of a capacity control valve, and FIG. FIG. 3 is a hydraulic circuit diagram showing a second embodiment, and FIG. 4 is a hydraulic circuit diagram showing a conventional technique. 1 ... hydraulic motor, 1A ... variable capacity part, 2 ... inertial body,
3 ... variable displacement actuator, 4 ... displacement control valve, 4A
… Hydraulic pilot unit, 5… Hydraulic pump, 6… Tank, 7A, 7B… Main pipeline, 8… Directional switching valve, 9… Counter balance valve, 15… Pilot pump, 16… Control pipe Channel, 21 ... pressure reducing valve (pressure control valve), 22 ... auxiliary line,
24A, 24B ... check valve (backflow prevention means), 25, 35 ... throttle passage, 31 ... switching valve (pressure control valve), 32 ... low pressure relief valve, 33 ... high pressure relief valve.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭61−165432（ＪＰ，Ａ) 特開 平３−229003（ＪＰ，Ａ) 実開 平１−111880（ＪＰ，Ｕ) ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-165432 (JP, A) JP-A-3-229003 (JP, A) JP-A-1-111880 (JP, U)
Claims (4)
容量型の油圧モータと、該油圧モータの容量可変部を駆
動する容量可変アクチュエータと、該アクチュエータに
供給する圧油を切換制御する油圧パイロット式の容量制
御弁と、前記油圧モータと主油圧源との間を接続した一
対の主管路の途中に設けられ、前記油圧モータの回転方
向を切換える方向切換弁と、該方向切換弁と油圧モータ
との間に位置して、前記各主管路の途中に設けられたカ
ウンタバランス弁と、前記容量制御弁の油圧パイロット
部と副油圧源との間を接続した制御管路と、該制御管路
の途中に設けられ、前記容量制御弁を大容量位置と小容
量位置とに切換えるべく、該制御管路内の圧力を制御す
る圧力制御弁とからなる可変容量型油圧モータの制御回
路において、前記制御管路には圧力制御弁と容量制御弁
の油圧パイロット部との間に位置して補助管路の一端側
を接続し、該補助管路の他端側を前記油圧モータとカウ
ンタバランス弁との間で前記各主管路に一対の逆流防止
手段を介して接続したことを特徴とする可変容量型油圧
モータの制御回路。1. A variable displacement hydraulic motor having a variable displacement unit for driving an inertial body, a variable displacement actuator for driving a variable displacement unit of the hydraulic motor, and switching control of pressure oil supplied to the actuator. A hydraulic pilot type displacement control valve, a directional switching valve provided in the middle of a pair of main pipelines connected between the hydraulic motor and a main hydraulic power source, for switching a rotation direction of the hydraulic motor, and a directional switching valve A counterbalance valve provided in the middle of each of the main pipelines, a control pipeline connecting between a hydraulic pilot unit of the displacement control valve and a sub-hydraulic source, A control circuit for a variable displacement hydraulic motor, which is provided in the middle of the control line and comprises a pressure control valve for controlling the pressure in the control line so as to switch the displacement control valve between a large displacement position and a small displacement position. In the above One end of the auxiliary line is connected to the control line between the pressure control valve and the hydraulic pilot portion of the capacity control valve, and the other end of the auxiliary line is connected to the hydraulic motor and the counterbalance valve. A control circuit for a variable displacement hydraulic motor, wherein the control circuit is connected to each of the main pipelines via a pair of backflow prevention means.
ク圧よりも高い圧力で少なくとも二段階に制御し、これ
によって前記容量制御弁を大容量位置と小容量位置とに
切換えてなる特許請求の範囲（１）項記載の可変容量型
油圧モータの制御回路。2. The pressure control valve controls the pressure in a control line at a pressure higher than a tank pressure in at least two stages, thereby switching the capacity control valve between a large capacity position and a small capacity position. The control circuit for a variable displacement hydraulic motor according to claim 1.
圧より高くなると大容量位置に切換わり、所定圧より低
くなると小容量位置に切換わる構成としてなる特許請求
の範囲（１）項または（２）項記載の可変容量型油圧モ
ータの制御回路。3. The capacity control valve is configured to switch to a large capacity position when the pressure in the control line is higher than a predetermined pressure, and to switch to a small capacity position when the pressure is lower than the predetermined pressure. The control circuit of the variable displacement hydraulic motor according to the paragraph or (2).
と副油圧源との間に位置して流量制御手段を設けてなる
特許請求の範囲（１）項，（２）項または（３）項記載
の可変容量型油圧モータの制御回路。4. The control line according to claim 1, further comprising a flow control means provided between the connection point of the auxiliary line and the auxiliary hydraulic power source in the middle of the control line. Or the control circuit of the variable displacement hydraulic motor according to (3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1253166A JP2724888B2 (en) | 1989-09-28 | 1989-09-28 | Control circuit of variable displacement hydraulic motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1253166A JP2724888B2 (en) | 1989-09-28 | 1989-09-28 | Control circuit of variable displacement hydraulic motor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03115624A JPH03115624A (en) | 1991-05-16 |
| JP2724888B2 true JP2724888B2 (en) | 1998-03-09 |
Family
ID=17247451
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1253166A Expired - Fee Related JP2724888B2 (en) | 1989-09-28 | 1989-09-28 | Control circuit of variable displacement hydraulic motor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2724888B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2545158Y2 (en) * | 1992-06-26 | 1997-08-25 | 住友建機株式会社 | Hydraulic motor drive circuit |
| GB2490320A (en) * | 2011-04-20 | 2012-10-31 | Bamford Excavators Ltd | Hydraulic circuit with back-up pressure system to prevent cavitation |
-
1989
- 1989-09-28 JP JP1253166A patent/JP2724888B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03115624A (en) | 1991-05-16 |
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| Date | Code | Title | Description |
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| LAPS | Cancellation because of no payment of annual fees |