Volumetric hydraulic drive calculation - DBE, Drawings

Contents

Introduction

Initial data for calculation of hydraulic drive

1. Description of the schematic hydraulic diagram of lifting of the fastener flap with bucket with capacity over 10 m

2. Calculation of volumetric hydraulic drive

2.1 Determination of hydraulic drive and pump power

2.2 Pump Selection

2.3Determination of internal diameter of hydraulic lines, liquid speeds

2.4 Selection of hydraulic equipment, operating fluid conditioners

2.5Recalculating pressure losses in hydraulic lines

2.6 Calculation of hydraulic cylinders

2.7 Thermal calculation of hydraulic drive

Conclusion

List of literature

Introduction

The development of modern machines and mechanisms is associated with the constant improvement of drives and their actuators and, first of all, with the widespread introduction of a hydraulic drive.

The volume hydraulic drive gives considerable economic effect therefore it finds the increasing application by mobile cars, in construction and transport mechanical engineering, machine-tool construction, shipbuilding, tractor construction, hoisting-and-transport cars and mechanisms, etc.

The use of hydraulic drive in lifting, construction, road and communal machines, intended mainly for outdoor operation, in a wide range of temperatures, with increased dust content of air, frequent short-term overloads and vibration, required the organization of specialized production of hydraulic equipment that meets specific operating conditions.

Knowledge of the characteristics and indicators of hydraulic equipment elements allows developers to choose rational, for given operating conditions, hydraulic drive scheme and ready-made hydraulic elements for its configuration (pumps, hydraulic motors, hydraulic equipment, etc.) when creating new machines and mechanisms.

Description of the schematic hydraulic diagram of lifting of the fastener flap with bucket with capacity over 10 m3

In heavy-duty fasteners, electrohydraulic control of hydraulic motors is used. Electrohydraulic distributors are installed in the immediate vicinity of hydraulic cylinders on the trailed part of the fastener, and only two high or low pressure hoses are passed from the pump and hydraulic tank through the saddle or coupling device instead of six. This improves the reliability of the hydraulic drive, reduces pressure losses in the pipelines, does not clutter the saddle chain device and improves the appearance of the fasteners. In addition, the use of electrohydraulic control improves working conditions and reduces operator fatigue.

Hydraulic circuit includes the following elements: hydraulic tank, non-adjustable pump, electrohydraulic distributors, hydraulic cylinders for lifting and lowering the damper, electrohydraulic safety valve, filter with overflow valve, pressure gauges, temperature sensor.

The principle of operation of the hydraulic drive is as follows. When the distributors electromagnets are switched off, the flow of liquid from the pump through the normally open safety valve and filter is sent back to the hydraulic tank.

Actuation of electromagnet of one of distributors moves control spool, which connects end cavity of main spool with drain hydraulic line, due to the fact that before filter there is always pressure of liquid flow of at least 0.3 MPa, drain hydraulic line is used as control hydraulic line.

Moving to one of the extreme positions (right or left), the main slide connects the rod (or piston) chambers of the hydraulic cylinders with the pressure hydraulic line of the pump, and the opposite chambers (piston or rod) - with the drain hydraulic line. Thus, reciprocating motion of rods of hydraulic cylinders and with them movement of working equipment of fastener is provided.

When the distributors electromagnets are switched off, the normally open control spool of the safety valve directs the flow of liquid from the pump to the drain. When any solenoid of the distributor is switched on, simultaneously with it the solenoid of the safety valve control spool is turned on, and the normally open valve control spool is closed.

Liquid flow from pump is directed to distributors. If the pressure in the system rises above the maximum, the safety valve operates and liquid from the pump enters the hydraulic tank. Pressure gauges in pressure and drain lines are installed for monitoring of hydraulic drive operation mode, and remote temperature sensor is installed in hydraulic tank.

Conclusion

Volumetric hydraulic drive is an integral part of modern mobile machines, widely used in mechanical engineering and industrial equipment.

The general trends in the further improvement of hydraulic equipment are as follows:

expansion of the ranges of change of the main parameters (primarily pressures (up to 32... 40 MPa) and operating fluid flow rates);

application of electrohydraulic control and electronic

devices in drives;

improving reliability and durability of the most critical elements of hydraulic systems;

reduction of metal consumption and noise level created during operation of hydraulic equipment;

universalization and unification of hydraulic equipment. Increasing the efficiency of hydraulic machines in the entire range of changing operating parameters makes it possible to expand the scope of their application.

As a result of the work, he designed a volumetric hydraulic drive, calculated the pump power and chose an axial-piston adjustable single-flow pump 313.3.160, with a maximum working volume of 160 cm3.

He calculated the internal diameters of the hydraulic lines, the speed of the liquid and selected the spool type hydraulic distributors, a safety valve of indirect action, a check valve of type 61, a filter with a size of 1.1.3225 along the conditional passage equal to 32 mm.

He calculated the hydraulic cylinder, and calculated the actual force on the rod and the actual speed of movement of the hydraulic cylinder rod by the diameter of the hydraulic cylinder and rod. After comparing the actual indicators with nominal ones, he determined an error that did not exceed 10%.