Because the hydraulic system of the forming machine is used more and the load of each station is different, it is very meaningful to use variable pump in the system.

青海分公司成型机液压系统中使用的都是KHD公司生产的恒压变量泵。该泵最大输出压力为40MPa，并具有噪声低、寿命长、轴向吸入径向负载、消耗功率低、集成块设计控制迅速、自始至终运转、具有泵的定位仪等特点。

The constant pressure variable displacement pump produced by KHD company is used in the hydraulic system of the molding machine of Qinghai branch. The maximum output pressure of the pump is 40MPa, and has the characteristics of low noise, long life, radial load of axial suction, low consumption power, rapid control of integrated block design, beginning to end operation, and pump positioning instrument.

一、工作原理

1. Working principle

带滑靴结构的轴向柱塞泵是目前使用最广泛的轴向柱塞泵，安放在缸体中的柱塞通过滑靴与斜盘相接触，当传动轴带动缸体旋转时，斜盘将柱塞从缸体中拉出或推回，完成吸排油过程。柱塞与缸孔组成的工作容腔中的油液通过配油盘分别与泵的吸、排油腔相通。变量机构用来改变斜盘的倾角，通过调节斜盘的倾角可改变泵的排量。

The axial piston pump with the slipper structure is the most widely used axial piston pump at present. The plunger in the cylinder body is in contact with the slanted disc. When the drive shaft drives the cylinder body to rotate, the slanting disc pulls the plunger out or back from the cylinder and completes the oil absorption process. The oil in the working chamber of the plunger and the cylinder bore is communicated with the suction and discharge chamber of the pump respectively through the oil distribution plate. The variable mechanism is used to change the inclination angle of the swashplate, and the displacement of the pump can be changed by adjusting the inclination angle of the swashplate.

二、柱塞泵的维护

Two, the maintenance of the plunger pump

斜盘式轴向柱塞泵一般采用缸体转动、端面配流的形式。缸体端面上镶有一块由双金属板与钢配油盘组成的摩擦副，而且大多数是采用平面配流的方法，所以维修比较方便。配油盘是轴向柱塞泵的关键部件之一，泵工作时，一方面工作腔的高压油把缸体推向配油盘，另一方面配油盘和缸体间的油膜压力形成对缸体的液压反推力使缸体背离配油盘。缸体对配油盘的设计液压压紧力Fn略大于配油盘对缸体的液压反推力Ff，即Fn/Ff=1.05~1.1，使泵工作正常并保持较高的容积效率。

The swashplate axial piston pump usually adopts the form of cylinder rotation and end flow distribution. The end face of the cylinder is inlaid with a pair of friction pairs consisting of a double metal plate and a steel plate with a steel plate, and most of them are by the method of plane flow matching, so it is convenient to maintain. The oil tray is one of the key parts of the axial piston pump. On the one hand, the high pressure oil of the working chamber pushes the cylinder to the oil tray. On the other hand, the oil film pressure between the oil tray and the cylinder body forms the hydraulic reverse thrust to the cylinder body, which makes the cylinder body deviate from the oil tray. The hydraulic pressure Fn of the cylinder body is slightly larger than the hydraulic reverse thrust Ff of the oil tray to the cylinder body, that is, Fn/Ff=1.05~1.1, so that the pump works well and keeps the high volume efficiency.

实际上，由于油液的污染，往往使配油盘与缸体之间产生轻微磨损。特别是高压时，即使轻微的磨损也可以使液压反推力Ff增大，从而破坏Fn>Ff的关系，使配油盘和缸体间产生缝隙而不能正常工作。所以在柱塞泵的检修和维护过程中，应着重检查配油盘和缸体这一对摩擦副的使用情况，即使有轻微的磨损，也应及时修复。

In fact, due to the contamination of oil, slight wear occurs between the oil distributor and the cylinder block. In particular, high pressure, even slight wear and tear can make the hydraulic reverse thrust Ff increase, thereby destroying the relationship between the Fn>Ff and producing gaps between the oil plate and the cylinder and not working normally. Therefore, in the process of maintenance and maintenance of the plunger pump, we should focus on checking the use of the pair of friction pairs with the oil tray and cylinder, even if there is a slight wear and tear, it should be repaired in time.

三、常见故障处理

Three. Common troubleshooting

1．液压泵输出流量不足或不输出油液

1. the output flow of the hydraulic pump is insufficient or the oil is not exported.

(1)吸入量不足。原因是吸油管路上的阻力过大或补油量不足。如泵的转速过大，油箱中液面过低，进油管漏气，滤油器堵塞等。

(1) insufficient inhalation. The reason is that the resistance of the suction line is too large or the amount of oil is insufficient. If the speed of the pump is too large, the liquid level in the tank is too low, the intake pipe leaks, and the oil filter is blocked.

(2)泄漏量过大。原因是泵的间隙过大，密封不良造成。如配油盘被金属碎片、铁屑等划伤，端面漏油；变量机构中的单向阀密封面配合不好，泵体和配油盘的支承面有砂眼或研痕等。可以通过检查泵体内液压油中混杂的异物判别泵被损坏的部位。

(2) the amount of leakage is too large. The reason is that the clearance of the pump is too large, resulting in poor sealing. For example, the oil tray is scratched by metal fragments and iron chips, and the end face leaks. hupozhuanmj.75ix.cn jianchajingj.75ix.cn liushuicaon.75ix.cndianlancaos.75ix.cn shuichi.89ix.com dianlanguan.89ix.comThe tight cover of the one-way valve in the variable mechanism is not good, and the supporting surface of the pump body and the matching oil tray has sand or grind marks and so on. The damaged parts of the pump can be judged by checking the foreign matter mixed in the hydraulic oil of the pump body.

(3)倾斜盘倾角太小，泵的排量少，这需要调节变量活塞，增加斜盘倾角。

(3) the inclination angle of the tilting plate is too small and the displacement of the pump is small. This requires adjusting the piston of the variable piston and increasing the inclination angle of the swashplate.

2．中位时排油量不为零

The amount of oil in the 2. position is not zero

变量式轴向柱塞泵的斜盘倾角为零时称为中位，此时泵的输出流量应为零。但有时会出现中位偏离调整机构中点的现象，在中点时仍有流量输出。其原因是控制器的位置偏离、松动或损伤，需要重新调零、紧固或更换。泵的角度维持力不够、倾斜角耳轴磨损也会产生这种现象。

When the tilting angle of the variable axial piston pump is zero, it is called the middle position. At this point, the output flow of the pump should be zero. But sometimes there is a midpoint deviation adjustment mechanism, and there is still flow output at midpoint. The reason is that the controller's position is deviated, loosened or damaged, and it needs to be reset, tightened or replaced. The angle of the pump is not enough and the angle of the trunnion is worn.

3．输出流量波动

3. output flow fluctuation

输出流量波动与很多因素有关。对变量泵可以认为是变量机构的控制不佳造成，如异物进入变量机构，在控制活塞上划出阶痕、磨痕、伤痕等，造成控制活塞运动不稳定。由于放大器能量不足或零件损坏、含有弹簧的控制活塞的阻尼器效能差，都会造成控制活塞运动不稳定。流量不稳定又往往伴随着压力波动。这类故障一般要拆开液压泵，更换受损零部件，加大阻尼，提高弹簧刚度和控制压力等。

The output flow fluctuation is related to many factors. The variable pump can be considered to be a poor control of the variable mechanism, such as the entry of the foreign body into the variable mechanism, the step mark, the grinding mark and the scar on the control piston, which can lead to the control of the piston movement instability. Because the energy of the amplifier is not enough or the parts are damaged and the damper of the control piston with spring is not effective, it will cause the control of piston motion instability. Flow instability is often accompanied by pressure fluctuations. This kind of fault usually dismantled hydraulic pumps, replaced damaged parts, increased damping, increased spring stiffness and control pressure.

4．输出压力异常

4. abnormal output pressure

泵的输出压力是由负载决定的，与输入转矩近似成正比。输出压力异常有两种故障。

The output pressure of the pump is determined by the load and is approximately proportional to the input torque. There are two kinds of faults in the abnormal output pressure.

(1)输出压力过低

(1) low output pressure

当泵在自吸状态下，若进油管路漏气或系统中液压缸、单向阀、换向阀等有较大的泄漏，均会使压力升不上去。这需要找出漏气处，紧固、更换密封件，即可提高压力。溢流阀有故障或调整压力低，系统压力也上不去，应重新调整压力或检修溢流阀。如果液压泵的缸体与配流盘产生偏差造成大量泄漏，严重时，缸体可能破裂，则应重新研磨配合面或更换液压泵。

When the pump is self priming, if the oil inlet pipe leaks or the hydraulic cylinder, one-way valve and reversing valve in the system are leaked, the pressure will not rise. It is necessary to find out the leak location, tighten and replace the seals, so that the pressure can be increased. The relief valve is faulty or the adjustment pressure is low, and the system pressure is not up. It is necessary to readjust the pressure or overhaul the relief valve. If the cylinder block of the hydraulic pump is deviate from the distributor plate, resulting in a great deal of leakage, when the cylinder block may be cracked, the mating surface or the replacement of the hydraulic pump should be redone.

(2)输出压力过高

(2) exorbitant output pressure

若回路负载持续上升，泵的压力也持续上升，当属正常。若负载一定，泵的压力超过负载所需压力值，则应检查泵以外的液压元件，如方向阀、压力阀、传动装置和回油管道。若最大压力过高，应调整溢流阀。

If the loop load continues to rise, the pump pressure will continue to rise, which is normal. If the load is certain, the pressure of the pump exceeds the pressure required for the load, then the hydraulic components outside the pump, such as the direction valve, pressure valve, transmission device and oil return pipe, should be checked. If the maximum pressure is too high, the overflow valve should be adjusted.

5．振动和噪声

5. vibration and noise

振动和噪声是同时出现的。它们不仅对机器的操作者造成危害，也对环境造成污染。

Vibration and noise are at the same time. They not only cause harm to the operators of the machine, but also pollute the environment.

(1)机械振动和噪声

(1) mechanical vibration and noise

如泵轴和电机轴不同心或顶死，旋转轴的轴承、联轴节损伤，弹性垫破损和装配螺栓松动均会产生噪声。对于高速运转或传输大能量的泵，要定期检查，记录各部件的振幅、频率和噪声。如泵的转动频率与压力阀的固有频率相同时，将会引起共振，

If the pump shaft and motor shaft are not concentric or dead, rotating shaft bearing, coupling damage, elastic pad damage and bolt loosening will produce noise. For pumps running at high speeds or transmitting large energy, they should be checked regularly, recording the amplitude, frequency and noise of each component. If the pump's rotational frequency is the same as the natural frequency of the pressure valve, it will cause resonance.