SU787580A1 - Loader hydraulic drive - Google Patents

Description

I

BACKGROUND OF THE INVENTION The invention relates to a device for leveling a loader bucket during lifting. iu boom.

The hydraulic drive of the loader is known, which consists of two control valves, connected by hydraulic bearings to the hydraulic cylinders of the boom and the bucket 1.

The disadvantage of this drive is the impossibility to ensure the alignment of the bucket in the process of lifting the boom, because of which there are losses of soil and a decrease in the performance of the loader.

Also known is a hydraulic drive, which has a hydraulic unit for connecting the cavities of the boom and bucket hydraulic cylinders, the tracking cylinder, into which the working fluid must be supplied during the boom lift and rotation of the bucket in order to level the bucket and connect the opposite side of the bucket hydraulic cylinder with the drain 1.

The use of an additional cylinder 20 for tracking the position of the loader bucket complicates the drive of the loader, causing an increase in its metal intensity, labor intensity and cost. In addition, the tracking cylinder

loads a loader boom with additional forces. In the event of failure of any of the safety devices, these forces can cause damage to the boom. The stand (frame) of the loader is also overloaded.

The purpose of the invention is to increase the durability of the drive.

This goal is achieved by the fact that the waterworks is designed as a flow divider, with the opposite cavities of the hydraulic cylinders being interconnected via a backflow controlled valve, the control chamber of which is communicated with the flow divider.

The drawing shows the hydraulic circuit of the loader drive.

The hydraulic drive consists of control valves 1 and 2, which are connected by hydraulic lines 3 and 4 to the hydraulic cylinder 5 of the boom 6 rotation and hydraulic lines 7 and 8 to the hydraulic cylinder 9 of the bucket 10 rotation.

Claims (2)

The hydraulic line 11 from the boom hydraulic cylinder control center 1 is connected via the flow divider 12 and the hydraulic line 13 to the boom hydraulic cylinder cavity 14 (for lifting the boom) and through the check valve 15 and the hydraulic line 16 to the bucket hydraulic cylinder cavity 17. The flow divider consists of the housing 18, the plunger 19, the inlet channel 20, the output channels 21 and 22, throttle holes 23 and 24. To freely drain the fluid from the cavity 14 of the boom cylinder, when it is lowered, a check valve 25 is used. The opposite cavity 26 of the bucket cylinder is connected through a check valve 27 and a controlled check valve 28 with an opposite cavity 29 of the hydraulic cylinder boom of the hydraulic line 4 — with the distributor 1 controlling the hydraulic cylinder of the boom. Hydraulic drive loader works as follows. When lifting the boom .6 with the loaded bucket 10, a certain part of the flow rate flows from the distributor 1 through the line 11, the channel .20, the throttle hole 24, the channel 21, the hydraulic line 13 into the cavity 14 of the hydraulic cylinder of the boom. Another determined part of the fluid flow through the throttle hole 24, the channel 22, the check valve 15, the hydraulic lines 16 and 7 enters the cavity 17 of the bucket cylinder. At the same time, in the cavity 17 of the bucket cylinder, some overpressure is formed, at which the check valve 28 opens, connected to the bucket cylinder cavity 17 by hydraulic lines 7 and 16. After opening the check valve 28, fluid from the cylinder 26 of the bucket cylinder begins to drain through the hydraulic line 8, the check valve 27, the valve 28, the hydraulic line 4 and the distributor 1. Simultaneously with the lifting of the boom 6, the bucket 10 starts to turn counterclockwise (leveling the bucket). Due to the appropriate choice of the diameters of the throttle holes 23 and 24 and the corresponding movement of the plunger 19, a kinematic connection is required between the position of the boom 6 and the rotation of the bucket 10 so that its upper edge 30 as the boom 6 rises is close to horizontal. This position is due to the use of the flow divider does not depend on the forces acting on the rods of the hydraulic cylinders 5 and 9. In the case of a clockwise rotation of the bucket at a higher speed that does not correspond to the boom lifting speed, which may occur, for example, a significant weight of the soil in the bucket, the fluid from the divider 12 flow will not have time to fill the cavity of the bucket 17 hydraulic cylinder and the excess pressure disappears there. At the same time, the return controlled valve 28 will close, shut off the discharge of fluid from the cavity of the hydraulic cylinder of the bucket and leveling the bucket will stop until overpressure occurs in the cavity of the hydraulic cylinder of the bucket, i.e. a certain amount of fluid entering the cavity 17 bucket cylinder. To lower the boom, fluid is supplied from distributor 1 through line 4 to boom cylinder 29 and discharges from cavity 14 through i-hydraulic line 3 and check valve 25. Back valve 27 serves to ensure that the working pressure acting in boom cylinder 29 during its lowering did not penetrate at that moment into the cavity 26 of the bucket cylinder. Otherwise, the pressure in the cavity 17 of the bucket cylinder will significantly exceed the working pressure in the hydraulic system (due to the difference in the area of the cavities 17 and 26), which can lead to ruptures of the flexible hoses installed in the hydraulic system. The check valve 15 is installed so that during the lowering of the boom 6, the connection of the cavity 17 of the bucket cylinder through the flow divider 12 to the hydraulic line 11, which, when the boom is lowered, is connected through the distributor 1 to the drain, to exclude. To rotate the bucket 10 clockwise (unloading the bucket in the upper position of the boom 6) fluid from the distributor 2 through the hydraulic line 7 is pumped into the cavity 17 of the hydraulic cylinder of the bucket, and the liquid is drained from the cavity 26 of the same hydraulic cylinder through the hydraulic line 8 and the distributor 2. Rotate the bucket 10 counterclockwise takes place after switching the distributor 2, when the liquid from this distributor is injected through the hydraulic line 8 into the cavity 26 of the hydraulic cylinder of the bucket, and the liquid is drained from the cavity 17 of the same hydraulic circuit. the cylinders is carried out through valve 7 and gidromagistral 2. Technical and economic efficiency is achieved by reducing the cost of the hydraulic drive and increasing the service life of the loader boom. Claims The hydraulic drive of the loader, including control valves, boom and bucket turn hydraulic cylinders, hydraulic lines, and hydraulic unit for boom lifting and bucket rotation at the same time, is located between the distributors and hydraulic cylinders, characterized in that the hydraulic unit is designed as a divider flow, and the opposite cavity hydrocylidov interconnected through the reverse