JP2536035B2 - Hydraulic control system for power vehicle - Google Patents
Hydraulic control system for power vehicleInfo
- Publication number
- JP2536035B2 JP2536035B2 JP63075052A JP7505288A JP2536035B2 JP 2536035 B2 JP2536035 B2 JP 2536035B2 JP 63075052 A JP63075052 A JP 63075052A JP 7505288 A JP7505288 A JP 7505288A JP 2536035 B2 JP2536035 B2 JP 2536035B2
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- hydraulic cylinder
- hydraulic
- oil
- control 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.)
- Expired - Lifetime
Links
Landscapes
- Lifting Devices For Agricultural Implements (AREA)
- Fluid-Pressure Circuits (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、トラクター等の動力車両の油圧制御装置
に関する。The present invention relates to a hydraulic control device for a power vehicle such as a tractor.
従来、この種の油圧制御装置は、特開昭62−265903号
公報に開示されている構成のものがある。具体的には、
第３図に示す従来例のように、作業機昇降用の油圧シリ
ンダー６′と油圧ポンプ25′とを結ぶ圧油供給油路28′
の途中に上昇側電磁式比例制御弁29′と、下降側電磁式
比例制御弁30′と、強制下降弁24′とを介装して設け、
制御部に下降指令が入ったときには、通常は下降側電磁
式比例制御弁30′のソレノイドが励磁され、油圧シリン
ダー６′内の圧力が所定圧を下回るときはこの強制下降
弁24′がタンク26′と連通する側に切り替わり、油圧シ
リンダー６′内に流入している作動油をタンク26′に排
出させてリフトアームを下降回動させるように構成して
いる。Conventionally, this type of hydraulic control device has a configuration disclosed in JP-A-62-265903. In particular,
As in the conventional example shown in FIG. 3, the hydraulic oil supply oil passage 28 'connecting the hydraulic cylinder 6'for raising and lowering the working machine and the hydraulic pump 25'.
An ascending side electromagnetic proportional control valve 29 ', a descending side electromagnetic proportional control valve 30', and a forced descending valve 24 'are provided in the middle of
When a descending command is input to the control unit, the solenoid of the descending side electromagnetic proportional control valve 30 'is normally energized, and when the pressure in the hydraulic cylinder 6'is below a predetermined pressure, the forced descending valve 24' is operated by the tank 26. It is configured to switch to the side communicating with the hydraulic cylinder 6'and to discharge the hydraulic oil flowing into the hydraulic cylinder 6'to the tank 26 'to rotate the lift arm downward.
この強制下降弁24′は、トラクター等のリフトアーム
に作業機が連結されていない軽負荷状態で油圧シリンダ
ー６′内の圧力が所定圧を下回るときに、開に切り替わ
って、リフトアームの下降側への回動を可能とするため
に設けられたものである。The forcible lowering valve 24 'is switched to open when the pressure in the hydraulic cylinder 6'is below a predetermined pressure in a light load state in which the working machine is not connected to the lift arm of the tractor or the like, and the lower side of the lift arm is lowered. It is provided in order to enable rotation to.
ところが、このような従来装置の場合には、下降側電
磁式比例制御弁30′の他にこのような特殊な強制下降弁
24′を必要とするものであるから製造コストが増大する
という欠点があった。However, in the case of such a conventional device, in addition to the descending side electromagnetic proportional control valve 30 ', such a special forced descending valve is used.
Since 24 'is required, there is a drawback that the manufacturing cost increases.
この発明は、上記した問題点に鑑みて提案するもので
あって、次のような技術的手段を講じた。即ち、機体に
連結された作業機を昇降する油圧シリンダー６を単動式
の油圧シリンダーで構成し、該油圧シリンダー６に対し
て、油圧ポンプ25からの圧油を供給するための油路28が
形成されると共に、この油路28に分岐して形成された排
油路48に、前記作業機の下降を行うためのパイロット圧
操作型の下降側開閉弁36が介装され、この下降側開閉弁
36を開閉操作するパイロット油路が、前記油圧シリンダ
ー６内の圧力が作用する油路40と、前記油圧ポンプ25の
圧力が作用する油路41との二系統の油路で形成され、油
圧ポンプ25が駆動状態にあるときは前記二系統のパイロ
ット油路の両油路40,41により油圧シリンダー６内の圧
力と油圧ポンプ25の圧力とが作用して下降側開閉弁36が
開閉操作され、油圧ポンプ25が非駆動状態にあるときは
前記二系統のパイロット油路のうち油圧シリンダー６内
の圧力が作用する油路40により油圧シリンダー６内の圧
力が作用して下降側開閉弁36が開閉操作されるよう構成
されたことを特徴とする動力車両の油圧制御装置の構成
とする。The present invention has been proposed in view of the above-mentioned problems, and has taken the following technical means. That is, the hydraulic cylinder 6 for moving up and down the working machine connected to the machine body is composed of a single-acting hydraulic cylinder, and an oil passage 28 for supplying pressure oil from the hydraulic pump 25 to the hydraulic cylinder 6 is provided. A drain pressure passage 48, which is formed and branches off to the oil passage 28, is provided with a pilot pressure operation type down side opening / closing valve 36 for lowering the working machine. valve
A pilot oil passage for opening / closing 36 is formed of two oil passages, that is, an oil passage 40 on which the pressure in the hydraulic cylinder 6 acts and an oil passage 41 on which the pressure of the hydraulic pump 25 acts. When 25 is in a driving state, the pressure inside the hydraulic cylinder 6 and the pressure of the hydraulic pump 25 are acted by both oil passages 40 and 41 of the pilot oil passages of the two systems to open / close the descending side opening / closing valve 36, When the hydraulic pump 25 is in the non-driving state, the pressure in the hydraulic cylinder 6 is applied by the oil passage 40 in the pilot oil passages of the two systems where the pressure in the hydraulic cylinder 6 acts, and the lowering side opening / closing valve 36 is opened / closed. A hydraulic control device for a power vehicle, which is configured to be operated.
以下、図面に基づいて、この発明の実施例の一つを説
明する。An embodiment of the present invention will be described below with reference to the drawings.
まず、構成から説明する。１はトラクターで、機体の
前後部に夫々前後輪２、２、３、３を備え、エンジン４
の回転動力をミッションケース５内の変速装置（図面省
略）を介して後輪３、３の推進輪に伝達すべく構成して
いる。ミッションケース５の上部には単動の油圧シリン
ダー６を内装する油圧シリンダーケース７が設けられ、
この油圧シリンダーケース７の左右両側部にはリフトア
ーム８、８が回動可能に枢着されている。トラクター１
の機体後下部にはロワーリンク９、９が枢着され、この
ロワーリンク９、９とリフトアーム８、８との間にリフ
トロッド11、11が介装連結されている。機体後上部に連
結されたトップリンク12と左右一対のロワーリンク９、
９とからなる３点リンク装置13の後部にはロータリ耕耘
装置14が昇降自在に連結されている。First, the configuration will be described. Reference numeral 1 is a tractor, which is provided with front and rear wheels 2, 2, 3, and 3 on the front and rear portions of the body, respectively, and has an engine 4
Is transmitted to the propulsion wheels of the rear wheels 3 and 3 via a transmission (not shown) in the transmission case 5. A hydraulic cylinder case 7 that houses a single-acting hydraulic cylinder 6 is provided above the mission case 5.
Lift arms 8, 8 are rotatably mounted on both left and right sides of the hydraulic cylinder case 7. Tractor 1
Lower links 9, 9 are pivotally attached to the lower rear part of the body of the vehicle, and lift rods 11, 11 are interposed between the lower links 9, 9 and the lift arms 8, 8. Top link 12 connected to the upper rear part of the fuselage and a pair of left and right lower links 9,
A rotary tiller 14 is connected to a rear portion of a three-point link device 13 composed of 9 and 9 so as to be vertically movable.
次に第２図に示す油圧回路を説明する。エンジン４の
回転動力にて駆動される油圧ポンプ25と作業機昇降用の
メインの油圧シリンダー６とは圧油供給油路28にて接続
され、その間に上昇側電磁式比例制御弁29と下降側電磁
式比例制御弁30とが介装されている。上昇側電磁式比例
制御弁29は、比例圧力制御弁32と流量制御弁33と圧力補
償弁34とからなり、流量制御弁33は油圧シリンダー６と
油圧ポンプ25との接続を遮断する室33aと油圧シリンダ
ー６と油圧ポンプ25とが連通する室33bとを有し、常態
ではスプリング33cの押圧力により圧油供給油路28を遮
断するように構成している。比例圧力制御弁32のソレノ
イド32aに電流が通電されると流量制御弁33に背圧がか
かり、圧油供給油路28と連通する側（33b側）に流量制
御弁33が切換わる。すると、油圧ポンプ25から送られた
作動圧油はこの流量制御弁33の室33bを通って前記メイ
ン油圧シリンダー６側に送られる。圧力補償弁34は前記
流量制御弁33が作用していないときには油圧ポンプ25か
らの作動油をタンクに流出させ、流量制御弁33が上昇側
に切換えられたときにはポンプ側圧力がこの圧力補償弁
34に背圧として作用し、圧油供給油路28中に圧力を封じ
込める。一方、前記下降側電磁式比例制御弁30は、昇降
用油圧シリンダー６内の作動圧油を排出制御するための
下降側のメインスプール36と、このメインスプール36に
掛かるパイロット圧を調整するパイロット圧制御弁37と
を有し、前記メインスプール36は、油圧シリンダー６と
油圧タンク26との連通を遮断する室36aと、連通状態に
維持する室36bとを備え、常態においては、スプリング3
8により遮断する側に切換えられている。前記パイロッ
ト圧制御弁37は油路40、41により油圧シリンダー６内の
シリンダー圧と油圧ポンプ25側のポンプ圧とが掛かるよ
うに構成され、両油路40、41の途中には逆止弁42、43が
介装されている。パイロット圧制御弁37のソレノイド37
aに電流が通電されると、油路44と45とを接続していた
このパイロット圧制御弁37が切換えられ、油路45は油路
40、41と接続状態におかれる。即ち、このパイロット圧
制御弁37のソレノイド37aに電流が流れると背圧がメイ
ンスプール36に掛かり、このメインスプール36が室36b
側に切換えられて油圧シリンダー６内の作動油をタンク
26内に排出させ、リフトアーム８、８を下降させる。こ
のパイロット圧制御弁37のソレノイド37aに通電する電
流値を変えることによりメインスプール36に掛かる背圧
を変更することができ、メインスプール36の前後の圧力
差を調整することができて、油圧シリンダー６からタン
ク26に回収される作動油の量を変更することができる。Next, the hydraulic circuit shown in FIG. 2 will be described. The hydraulic pump 25 driven by the rotational power of the engine 4 and the main hydraulic cylinder 6 for raising and lowering the working machine are connected by a pressure oil supply oil passage 28, and between the rising side electromagnetic proportional control valve 29 and the falling side. An electromagnetic proportional control valve 30 is installed. The ascending-side electromagnetic proportional control valve 29 includes a proportional pressure control valve 32, a flow rate control valve 33, and a pressure compensating valve 34. The flow rate control valve 33 includes a chamber 33a for disconnecting the connection between the hydraulic cylinder 6 and the hydraulic pump 25. It has a chamber 33b in which the hydraulic cylinder 6 and the hydraulic pump 25 communicate with each other, and is configured to normally shut off the pressure oil supply oil passage 28 by the pressing force of the spring 33c. When a current is applied to the solenoid 32a of the proportional pressure control valve 32, a back pressure is applied to the flow control valve 33, and the flow control valve 33 is switched to the side communicating with the pressure oil supply oil passage 28 (33b side). Then, the working pressure oil sent from the hydraulic pump 25 is sent to the main hydraulic cylinder 6 side through the chamber 33b of the flow control valve 33. The pressure compensating valve 34 causes the hydraulic oil from the hydraulic pump 25 to flow out to the tank when the flow control valve 33 is not operating, and when the flow control valve 33 is switched to the rising side, the pump side pressure is the pressure compensating valve 34.
It acts as a back pressure on 34 and confines the pressure in pressure oil supply passage 28. On the other hand, the descending side electromagnetic proportional control valve 30 includes a descending side main spool 36 for controlling discharge of the operating pressure oil in the lifting hydraulic cylinder 6 and a pilot pressure for adjusting the pilot pressure applied to the main spool 36. The main spool 36 includes a control valve 37, a chamber 36a that blocks communication between the hydraulic cylinder 6 and the hydraulic tank 26, and a chamber 36b that maintains the communication state.
Switched to the shutoff side by 8. The pilot pressure control valve 37 is configured so that the cylinder pressure in the hydraulic cylinder 6 and the pump pressure on the hydraulic pump 25 side are applied by oil passages 40 and 41, and a check valve 42 is provided in the middle of both oil passages 40 and 41. , 43 are installed. Solenoid 37 for pilot pressure control valve 37
When a current is applied to a, the pilot pressure control valve 37 that connects the oil passages 44 and 45 is switched, and the oil passage 45 is changed to the oil passage.
40 and 41 are connected. That is, when a current flows through the solenoid 37a of the pilot pressure control valve 37, back pressure is applied to the main spool 36, and the main spool 36 moves into the chamber 36b.
The hydraulic oil in the hydraulic cylinder 6 by switching to the side
It is discharged into 26, and the lift arms 8 and 8 are lowered. The back pressure applied to the main spool 36 can be changed by changing the value of the current supplied to the solenoid 37a of the pilot pressure control valve 37, and the pressure difference between the front and rear of the main spool 36 can be adjusted. The amount of hydraulic oil collected from 6 to the tank 26 can be changed.
次に上例の作用を説明する。トラクター１のエンジン
４を回転させて油圧ポンプ25を駆動すると作動圧油は圧
油供給油路28を通ってまず上昇側電磁式比例制御弁29に
至る。第２図は油圧昇降装置の制御弁が中立状態にある
ときを示しているが、図示外の油圧操作レバー等によ
り、作業機上昇側の信号が制御部に入力されると圧力制
御弁32のソレノイド32aが励磁されて、パイロット圧が
油路46を介して流量制御弁33に掛かり、このため流量制
御弁33は室33b側に切換えられて油圧シリンダー６へ圧
油が供給され、リフトアーム８、８を上昇回動させる。
一方、下降側電磁式比例制御弁30に下げ側の信号が入る
とパイロット圧制御弁37のソレノイド37aが励磁され、
このパイロット圧制御弁37が切換えられて油路45は油路
40および41と連通し、これによりメインスプール36には
油圧シリンダー６側の内圧あるいは油圧ポンプ25側の圧
力が掛けられ、室36b側に切換えられて流量制御されな
がら油圧シリンダー６内の作動油は油圧タンク26に回収
される。油路40、41中には逆止弁42、43が介装されてい
るから、作動中に作動油が逆流して油圧シリンダー６内
に流入したり、圧油供給油路28と合流するような不都合
は生じない。以上のように、この実施例においては、従
来必要としていた高価な強制下降弁24′を不用となし、
逆止弁42、43を追加する程度のわずかな変更で油圧制御
装置の制御弁を構成することができるので構成が簡潔に
なるとともに、安価に製造できる利点がある。Next, the operation of the above example will be described. When the engine 4 of the tractor 1 is rotated to drive the hydraulic pump 25, the working pressure oil reaches the rising side electromagnetic proportional control valve 29 through the pressure oil supply oil passage 28. FIG. 2 shows a case where the control valve of the hydraulic lifting device is in a neutral state. However, when a signal on the work machine rising side is input to the control section by a hydraulic operating lever (not shown) or the like, the pressure control valve 32 is turned on. The solenoid 32a is excited, and pilot pressure is applied to the flow rate control valve 33 via the oil passage 46. Therefore, the flow rate control valve 33 is switched to the chamber 33b side and pressure oil is supplied to the hydraulic cylinder 6 to lift the lift arm 8 , 8 are rotated upward.
On the other hand, when the down side signal is input to the down side electromagnetic proportional control valve 30, the solenoid 37a of the pilot pressure control valve 37 is excited,
This pilot pressure control valve 37 is switched to change the oil passage 45 to the oil passage.
By communicating with 40 and 41, the internal pressure on the hydraulic cylinder 6 side or the pressure on the hydraulic pump 25 side is applied to the main spool 36, and the hydraulic oil in the hydraulic cylinder 6 is switched while the flow rate is controlled by switching to the chamber 36b side. Collected in the hydraulic tank 26. Since the check valves 42, 43 are provided in the oil passages 40, 41, the working oil may flow backward during operation to flow into the hydraulic cylinder 6 or join the pressure oil supply oil passage 28. No inconvenience occurs. As described above, in this embodiment, the expensive forced lowering valve 24 'which is conventionally required is not necessary,
Since the control valve of the hydraulic control device can be configured with a slight change such as adding the check valves 42 and 43, the configuration is simple and the manufacturing cost is low.
この発明は前記の如く構成したので以下のような技術
的効果を奏する。Since the present invention is configured as described above, it has the following technical effects.
即ち、油圧ポンプ25が駆動状態にあるときは、二系統
のパイロット油路の両油路40,41により油圧シリンダー
６内の圧力と油圧ポンプ25の圧力とが作用して下降側開
閉弁36が開閉操作されるから、エンジンがアイドリング
状態になっているときなどで油圧ポンプ25の駆動回転数
が低い状態にあるときでも、下降作動させられ、トラク
ター等のリフトアームに作業機が連結されていない軽負
荷状態でも、エンジンを始動させるだけで、確実に且つ
安全に下降させられる。また、油圧ポンプ25が非駆動状
態にあるときは、二系統のパイロット油路のうち油圧シ
リンダー６内の圧力が作用する油路40により油圧シリン
ダー６内の圧力が作用して下降側開閉弁36が開閉操作さ
れるから、高価な強制下降弁を必要とせずに、エンジン
が低下している状態で連結された作業機を下降させられ
る。That is, when the hydraulic pump 25 is in a driving state, the pressure in the hydraulic cylinder 6 and the pressure of the hydraulic pump 25 are acted by both the oil passages 40 and 41 of the pilot oil passages of the two systems so that the descending side opening / closing valve 36 is operated. Since it is opened and closed, the engine is idling, and even when the hydraulic pump 25 has a low drive speed, it is lowered and the work implement is not connected to the lift arm of the tractor. Even under a light load, it can be lowered reliably and safely by simply starting the engine. Further, when the hydraulic pump 25 is in the non-driving state, the pressure in the hydraulic cylinder 6 acts due to the oil passage 40 in the pilot oil passages of the two systems in which the pressure in the hydraulic cylinder 6 acts, so that the down-side opening / closing valve 36 Since the open / close operation is performed, it is possible to lower the connected working machine in a state where the engine is lowered without requiring an expensive forced lowering valve.
図面はこの発明の実施例の一つを示し、第１図は動力車
両の全体側面図、第２図は油圧回路図、第３図は従来装
置の油圧回路図である。 符号の説明 １……トラクター ６……油圧シリンダー ８、８……リフトアーム ９、９……ロワーリンク 13……３点リンク装置 14……ロータリ耕耘装置 29……上昇側電磁式比例制御弁 30……下降側電磁式比例制御弁 36……メインスプール 37……パイロット圧制御弁The drawings show one of the embodiments of the present invention. FIG. 1 is an overall side view of a power vehicle, FIG. 2 is a hydraulic circuit diagram, and FIG. 3 is a hydraulic circuit diagram of a conventional device. Explanation of code 1 …… Tractor 6 …… Hydraulic cylinder 8,8 …… Lift arm 9,9 …… Lower link 13 …… Three-point link device 14 …… Rotary tiller 29 …… Rise side electromagnetic proportional control valve 30 ...... Downward solenoid proportional control valve 36 ...... Main spool 37 ...... Pilot pressure control valve
Claims (1)
リンダー６を単動式の油圧シリンダーで構成し、該油圧
シリンダー６に対して、油圧ポンプ25からの圧油を供給
するための油路28が形成されると共に、この油路28に分
岐して形成された排油路48に、前記作業機の下降を行う
ためのパイロット圧操作型の下降側開閉弁36が介装さ
れ、この下降側開閉弁36を開閉操作するパイロット油路
が、前記油圧シリンダー６内の圧力が作用する油路40
と、前記油圧ポンプ25の圧力が作用する油路41との二系
統の油路で形成され、油圧ポンプ25が駆動状態にあると
きは前記二系統のパイロット油路の両油路40,41により
油圧シリンダー６内の圧力と油圧ポンプ25の圧力とが作
用して下降側開閉弁36が開閉操作され、油圧ポンプ25が
非駆動状態にあるときは前記二系統のパイロット油路の
うち油圧シリンダー６内の圧力が作用する油路０により
油圧シリンダー６内の圧力が作用して下降側開閉弁36が
開閉操作されるよう構成されたことを特徴とする動力車
両の油圧制御装置1. A hydraulic cylinder 6 for raising and lowering a working machine connected to a machine body is composed of a single-acting hydraulic cylinder, and oil for supplying pressure oil from a hydraulic pump 25 to the hydraulic cylinder 6 is provided. A passage 28 is formed, and a drain pressure passage 48 formed by branching to the oil passage 28 is provided with a pilot pressure operated lowering side opening / closing valve 36 for lowering the working machine. A pilot oil passage for opening and closing the descending side on-off valve 36 is an oil passage 40 on which the pressure in the hydraulic cylinder 6 acts.
And an oil passage 41 on which the pressure of the hydraulic pump 25 acts, and two oil passages 40 and 41 of the pilot oil passages of the two systems when the hydraulic pump 25 is in a driving state. When the pressure in the hydraulic cylinder 6 and the pressure of the hydraulic pump 25 act to open / close the lowering side opening / closing valve 36 and the hydraulic pump 25 is in a non-driving state, the hydraulic cylinder 6 in the pilot oil passages of the two systems is A hydraulic control device for a power vehicle, characterized in that the pressure inside the hydraulic cylinder 6 is actuated by the oil passage 0 on which the internal pressure acts to open and close the descending side on-off valve 36.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63075052A JP2536035B2 (en) | 1988-03-28 | 1988-03-28 | Hydraulic control system for power vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63075052A JP2536035B2 (en) | 1988-03-28 | 1988-03-28 | Hydraulic control system for power vehicle |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6029341A Division JP2626543B2 (en) | 1994-02-28 | 1994-02-28 | Hydraulic control device for powered vehicle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01247003A JPH01247003A (en) | 1989-10-02 |
| JP2536035B2 true JP2536035B2 (en) | 1996-09-18 |
Family
ID=13565042
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63075052A Expired - Lifetime JP2536035B2 (en) | 1988-03-28 | 1988-03-28 | Hydraulic control system for power vehicle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2536035B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2549204B2 (en) * | 1990-12-26 | 1996-10-30 | 株式会社クボタ | Work vehicle operating structure |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53131370A (en) * | 1977-04-21 | 1978-11-16 | Kawasaki Heavy Ind Ltd | Oil pressure circuit |
| JPS5721802U (en) * | 1980-07-15 | 1982-02-04 |
-
1988
- 1988-03-28 JP JP63075052A patent/JP2536035B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01247003A (en) | 1989-10-02 |
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