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液壓機液壓系統泄漏的原因,控制液壓系統泄漏的控制辦法

液壓機液壓系統泄漏的原因,控制液壓系統泄漏的控制辦法

作者:admin    來源:未知    發布時間:2020-08-26 18:53    瀏覽量:

一、液壓機液壓系統泄漏的原因

(1)設計及制造的缺陷所造成的;

(2)沖擊和振動造成管接頭松動;

(3)動密封件及配合件相互磨損(液壓缸尤甚);

(4)油溫過高及橡膠密封與液壓油不相容而變質。下面就結合以上幾個方面淺談一下控制泄漏的措施。

 

二、控制液壓機液壓系統泄漏的控制辦法

 

辦法一:設計及制造缺陷的解決方法

1、液壓元件外配套的選擇往往在液壓機液壓系統的泄漏中起著決定性的影響。這就決定我們技術人員在新產品設計、老產品的改進中,對缸、泵、閥件,密封件,液壓輔件等的選擇,要本著好中選優,優中選廉的原則慎重的、有比較的進行。

2、合理設計安裝面和密封面:當閥組或管路固定在安裝面上時,為了得到滿意的初始密封和防止密封件被擠出溝槽和被磨損,安裝面要平直,密封面要求精加工,表面粗糙度要達到0.8μm,平面度要達到0.01/100mm。表面不能有徑向劃痕,連接螺釘的預緊力要足夠大,以防止表面分離。

3、在制造及運輸過程中,要防止關鍵表面磕碰,劃傷。同時對裝配調試過程要嚴格的進行監控,保證裝配質量。

4、對一些液壓機液壓系統的泄露隱患不要掉已輕心,必須加以排除。

 

辦法二:減少沖擊和振動

為了減少承受沖擊和振動的管接頭松動引起的液壓機液壓系統的泄漏,可以采取以下措施:

①使用減震支架固定所有管子以便吸收沖擊和振動;

②使用低沖擊閥或蓄能器來減少沖擊;

③適當布置壓力控制閥來保護系統的所有元件;

④盡量減少管接頭的使用數量,管接頭盡量用焊接連接;

⑤使用直螺紋接頭,三通接頭和彎頭代替錐管螺紋接頭;

⑥盡量用回油塊代替各個配管;

⑦針對使用的最高壓力,規定安裝時使用螺栓的扭矩和堵頭扭矩,防止結合面和密封件被蠶食;

⑧正確安裝管接頭。

 

辦法三:減少液壓機液壓系統動密封件的磨損

大多數動液壓機液壓系統密封件都經過精確設計,如果動密封件加工合格,安裝正確,使用合理,均可保證長時間相對無泄漏工作。從設計角度來講,設計者可以采用以下措施來延長動密封件的壽命:

1、消除活塞桿和驅動軸密封件上的側載荷;

2、用防塵圈、防護罩和橡膠套保護活塞桿,防止磨料、粉塵等雜質進入;

3、設計選取合適的過濾裝置和便于清洗的油箱以防止粉塵在油液中累積;

4、使活塞桿和軸的速度盡可能低。

 

辦法四:對靜密封件的要求

靜密封件在剛性固定表面之間防止油液外泄。合理設計液壓機液壓系統密封槽尺寸及公差,使安裝后的密封件到一定擠壓產生變形以便填塞配合表面的微觀凹陷,并把密封件內應力提高到高于被密封的壓力。當零件剛度或螺栓預緊力不夠大時,配合表面將在油液壓力作用下分離,造成間隙或加大由于密封表面不夠平而可能從開始就存在的間隙。隨著配合表面的運動,靜密封就成了動密封。粗糙的配合表面將磨損密封件,變動的間隙將蠶食密封件邊緣。

 

方案五:控制油溫防止密封件變質

液壓機密封件過早變質可能是由多種因素引起的,一個重要因素是油溫過高。溫度每升高10℃則密封件壽命就會減半,所以應合理設計高效液壓系統或設置強制冷卻裝置,使最佳油液溫度保持在65℃以下;工程機械不許超過80℃;另一個因素可能是使用的油液與密封材料的相容性問題,應按使用說明書或有關手冊選用液壓油和密封件的型式和材質,以解決相容性問題,延長密封件的使用壽命。

 

 

1、 Causes of leakage in hydraulic system of hydraulic press

(1) Caused by design and manufacturing defects;

(2) The pipe joint is loose due to impact and vibration;

(3) Dynamic seals and mating parts wear each other (especially hydraulic cylinder);

(4) The oil temperature is too high and the rubber seal is incompatible with the hydraulic oil. The following is the combination of the above several aspects on the control of leakage measures.

2、 Control method of hydraulic system leakage control of hydraulic press

Solution 1: solutions to design and manufacturing defects

1. The selection of external matching of hydraulic components often plays a decisive role in the leakage of hydraulic system of hydraulic press. This determines that in the design of new products and the improvement of old products, the selection of cylinders, pumps, valves, seals, hydraulic accessories, etc. should be based on the principle of selecting the best from the good and selecting the low from the excellent carefully and comparatively.

2. Reasonable design of the installation surface and sealing surface: when the valve group or pipeline is fixed on the installation surface, in order to obtain a satisfactory initial seal and prevent the seal from being squeezed out of the groove and being worn, the installation surface shall be straight, the sealing surface shall be finished, the surface roughness shall be 0.8 μ m, and the flatness shall be 0.01/100 mm. There should be no radial scratches on the surface, and the pre tightening force of the connecting screw should be large enough to prevent surface separation.

3. In the process of manufacturing and transportation, the key surface should be prevented from bumping and scratching. At the same time, the assembly and debugging process should be strictly monitored to ensure the assembly quality.

4. The hidden danger of leakage of some hydraulic press hydraulic system must be eliminated.

Method 2: reduce impact and vibration

In order to reduce the leakage of the hydraulic system of hydraulic press caused by the loosening of pipe joints under impact and vibration, the following measures can be taken:

① All pipes shall be fixed with damping supports to absorb shock and vibration;

② Use low impact valve or accumulator to reduce impact;

③ Proper arrangement of pressure control valves to protect all components of the system;

④ The number of pipe joints shall be reduced as far as possible, and the pipe joints shall be welded as far as possible;

⑤ Use straight thread joint, tee joint and elbow instead of taper pipe thread joint;

⑥ Try to use oil return block instead of each piping;

⑦ According to the maximum pressure used, the torque of bolt and plug should be specified to prevent the joint surface and seal from being eroded;

⑧ Install the coupling correctly.

Three ways to reduce hydraulic seal wear

Most of the seals of the hydraulic system of the dynamic hydraulic press are designed accurately. If the seals are processed properly, installed correctly and used reasonably, they can ensure that there is no leakage for a long time. From the design point of view, designers can adopt the following measures to extend the life of dynamic seals:

1. Eliminate side load on piston rod and drive shaft seal;

2. Protect piston rod with dust ring, protective cover and rubber sleeve to prevent impurities such as abrasives and dust from entering;

3. In order to prevent the dust from accumulating in the oil, proper filter device and easy to clean oil tank are designed and selected;

4. Keep the rod and shaft speed as low as possible.

Method 4: requirements for static seals

Static seals prevent oil leakage between rigid fixed surfaces. The size and tolerance of sealing groove in hydraulic system of hydraulic press should be designed reasonably, so that the installed seal will deform to a certain extent, so as to fill the micro depression on the mating surface, and increase the internal stress of the seal to higher than the sealed pressure. When the part stiffness or bolt pre tightening force is not large enough, the mating surface will separate under the action of oil pressure, resulting in the gap or increasing the gap that may exist from the beginning due to the uneven sealing surface. With the movement of the mating surface, the static seal becomes the dynamic seal. The rough mating surface will wear the seal and the variable clearance will nibble at the seal edge.

Scheme 5: control oil temperature to prevent seal deterioration

Premature deterioration of hydraulic seal may be caused by many factors, one of which is high oil temperature. If the temperature increases by 10 ℃, the service life of the seal will be reduced by half. Therefore, it is necessary to reasonably design an efficient hydraulic system or set up a forced cooling device to keep the optimal oil temperature below 65 ℃; the construction machinery shall not exceed 80 ℃; another factor may be the compatibility between the oil used and the sealing material. The type and type of the hydraulic oil and seal shall be selected according to the operation manual or relevant manual Material to solve the compatibility problem and prolong the service life of the seal.

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