SU1218011A1 - Hydraulic slewing gear of platform - Google Patents

Description

The invention relates to a transport engineering, in particular to hydraulic drives of rotary excavators.

The aim of the invention is to increase the reliability of its work.

FIG. Figure 1 shows the hydraulic control circuit of the mechanism; in fig. 2 is an electrical control circuit of the hydraulic system of the mechanism.

The device has power cylinders 1-4, which are assembled in pairs of the same action. On hydraulic brake carts 5–8, pairs of brake hydraulic cylinders are installed, the working cavities of which are connected by common pressure lines. The directional control valves 9 and 10 serve to set the direction of rotation, and the directional control valves 11 and 12 serve to control the power cylinders 1-4. The hydraulic system also includes controlled throttles 13 and 14, pressure regulator 15, maintaining pressure constant in pressure line 16, drain line 17, pressure pump 18, filter 19, tank 20, limit switches 21 and 22, fixing the moment when the power cylinder rod is fully extended, and the limit switches 23 and 24, fixing the moment when the rods of the power cylinders are fully retracted.

The drive motor 25 is turned on by the switch 26. The contacts of the direction switch 27 are connected to the power supply circuit of the control winding 28-31 of the hydraulic distributors 9 and 10 and the contacts of the limit switches 21-24, through which the control windings 32-35 of the hydraulic distributor 11 and 12 are connected to the power supply circuit.

The device works as follows.

The direction switch 27 applies a voltage either to a pair of control windings 28 and 29, or to a pair of 30 and 31 of the valve 9 and 10. In this case, the working cavities of the brake hydraulic cylinders mounted on the brakes 5-8 are connected to either a rod or a hollow cavity power cylinders 1-4 and brake trolleys are braked either when retracting or when pulling the rods of power hydraulic cylinders. After switching on the switch 26, the drive motor begins to accelerate and as a result, the pressure gradually increasing at the outlet of the pressure pump 18 shifts the mechanism. In the diagram (FIG. 1), the position of the hydraulic switches is shown such that the rods of the power cylinders i and 2 begin to move out. In this case, the working cavities of the brake cylinders corresponding to them are connected to the pressure line 16, the tormoses are pressed

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And the brake carriages 5 and 6 move freely within the annular guide. At this time, the rods of the power cylinders 3 and 4 are retracted, the working cavities of the corresponding brake hydraulic cylinders are connected to the drain line 17, the brake carriages 7 and 8 are braked in the ring guide and the turntable is unfolded. Due to the fact that the resistance to movement of the brakes of the brake cart is less than the turning force of the platform, the rods of the hydraulic cylinders 1 and 2 are faster in the extreme position. At the moment when the rods of the power cylinders 3 and 4 are in the extreme position, the contact of the limit switch 24 is closed, which switches the control windings 32 and 33 through the opening contact of the switch 27 and starts to unwind the platform hydraulic cylinders 1 and 2. , and power

0 hydraulic cylinders 3 and 4, pushing the rods, make free play. The reverse switching is made by the limit switch 23 when the shafts of the power cylinders occupy a new extreme position.

When changing the direction of rotation

5, the control windings 30 and 31 are turned on through the closing contact of the directional switch 27, and the power cylinders are switched by limit switches 21 and 22.

This mode of switching of the control valves eliminates the delays of the mechanism in the so-called dead points. The magnitude of the force developed by the piston of the power cylinder depends not only on the pressure developed by the pressure pump, but also on the value of the hydraulic resistance of the supply line and the speed of movement of the force, and hence the speed of rotation of the mechanism.

Adjustable throttles 13 and 14 are inserted in the pressure lines to regulate the rate of rotation, one of which operates during the working stroke of the hydraulic cylinder and the second at return stroke. When the direction of rotation changes, their roles change places.

The resistance to rotation of the boom of a rotary excavator during working stroke varies depending on the thickness of the chips being cut. When the chip thickness is reduced, the mechanism automatically increases the speed, which makes it possible to stabilize the performance of the rotary excavator when working out relatively homogeneous geological structures without the use of additional control devices.

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Claims (1)

HYDRAULIC MECHANISM OF TURNING THE PLATFORM, including the support base with a roller circle on which the turntable is mounted, and a hydraulic system containing a pump connected through electrically operated distributors with turning cylinders, a tank, hydraulic brake trolleys and hydraulic lines, characterized in that, in order to increase reliability of his work, it is equipped with a direction switch mounted on a turntable and limit switches kinematically connected with hydraulic brake bogies and adjustable chokes installed between the pumps and the directional control cylinders, while the control windings of the valves are connected to the contacts of the direction switch through the contacts of the limit switches. Fig. (