SU1437838A1 - Closure and regulation arrangement of hydraulic system - Google Patents

Abstract

The invention relates to the field of automation and can be applied in hydraulic systems of machines. The purpose of the invention is to protect platforms or working bodies from damage due to sharp blows and to stop them if the hose breaks. When lifting the loading platform, the working medium is supplied from the distributor to the inlet 10 of the regulator 1, through the throttling channels 6 and the axial channel 5 to the inlet of the valve 2 and through the main channel 14 and the throttling channels 15 to the hydraulic cylinder. The plunger 7 of the regulator 1 and the ball 16 of the valve 2 are pressed by the springs, whereby the working medium flows through the maximum sections of the throttling channels, ensuring the required speed of lifting the load. When the platform is lowered under the action of the working medium, the plunger and the ball compress the springs, by changing the cross section of the throttle channels 6 of the regulator 1, the capacity of the regulator decreases, which ensures the constant speed of lowering the load. If the oil line 3 (breakage) is damaged, the ball 16 under the action of the pressure of the working medium closes the main channel 14 of the valve 2 and ensures that the working hydraulic cylinder, lowering it, or lifting it, locks the working cylinder. 7 il. and (L

Description

fS 15 17

Garden

H

CX) GS

with

The invention relates to the field of automation and can be used in hydraulic systems of machines, in particular for braking and locking the working cylinder, lowering the load, when there is a danger of injury to the operating personnel by the lowering platform (working member), the danger of damage to the lifting device when the load is quickly lowered and fluid is lost, flowing out of the cavity of the working cylinder in case of accidental damage or rupture of the hose (oil pipe).

The purpose of the Invention is to prevent the lowering platforms or working bodies from being damaged by sharp blows and to stop the platform or working bodies from accidentally cutting the hose.

FIG. 1 is a diagram of the connection of the locking control device to the hydraulic system; in fig. 2 - the locking and regulating device at the moment of raising the platform; in fig. 3 - the same, at the time of lowering the platform; in fig. 4 - the same, at the time of breakage of the oil pipe (hose); in fig. 5 is a cross section of the check valve; in fig. 6 and 7 sections of the automatic fluid flow regulator.

The shut-off and control device consists of an automatic regulator 1 of the fluid flow and a shut-off valve 2, interconnected by an oil line (pshang) 3.

The automatic flow regulator consists of a housing 4 with an axial channel 5 located in it, having in the longitudinal direction throttling channels 6 of variable section along the length, a plunger 7 with a spring 8 and a screw element 9 placed in channel 5. Channel 5 has an inlet 10 and output 11. The regulator is installed on the distributor by the plane 12.

The stop valve consists of a body 13 with a main channel 14 located therein, having in the longitudinal direction throttling channels 15 of a ball 16 with a spring 17 and a screw link 18. The main channel 14 has an inlet 19 and an outlet 20. The valve is mounted on the hydraulic cylinder with a plane 21.

Locking control device operates as follows.

0

five

0

five

0

five

0

five

When lifting the loading platform, the working medium is supplied from the distributor to the inlet 10 of the regulator 1 (see Fig. 1). Further along the throttling channels 6, channel 5 to the outlet 11 into the oil pipe 3, to the inlet 19 of valve 2 and through the main channel 14 and throttling channels 15 to the outlet 20 and to the hydraulic cylinder. The plunger 7 of the regulator 1 and the ball 16 of the valve 2 are pressed by the springs 8 and 17, due to which the working medium expires through the maximum sections of the throttling channels 6 and 15. This ensures the required speed of lifting the load.

When lowering the platform (working body) (see Fig.2) with or without load, the working medium flows out of the hydraulic cylinder through the outlet 20 of valve 2 and the throttling channels 15 of the main channel 14 to the inlet 19. Further along the oil pipe 3 through the outlet 11 of the regulator 1 and throttling channels 6 of channel 5 to the input 10 and to the distributor. Under the action of the pressure of the working medium, the plunger 7 of the regulator 1 and the ball 16. valve 2, moving, compresses the springs 8 and 17, while reducing the cross section of the throttle channels 6 of the regulator t creates an increased pressure at the outlet 11 of the regulator 1 and the inlet 19 of valve 2, which prevents the ball 16 from locking the main channel 14 of valve 2. A reduction in the cross section of the channels 6 of the regulator 1 leads to a decrease in the capacity of the channel 5 and, consequently, to a low speed of lowering the load.

If the oil line 3 (breakage) is damaged (see Fig. 3), the pressure at the inlet 19 of the valve 2 becomes equal to the atmospheric pressure. The ball 16 under the action of the pressure of the working medium compresses the spring 17 and locks the main channel 14 of the valve 2. This ensures the locking of the working cylinder, which lowers or lifts the load.

In order to ensure the constant speed of lowering of the load in the walls of the channel 5 of the regulator 1, the channels 6 are made in the form of spline grooves of variable cross section. Moreover, the change in the cross-sectional area of the throttle channels is selected as follows.

Under the influence of the pressure differential lr, which prevents the ball 16 of the shut-off valve 2 from completely closing the throttling channels 15,

314

the plunger 7 of the regulator 1, overcoming the resistance of the spring 8, moves to the distance ill from its initial position (see figure 2). The sections of the throttling channels located at the distribution from the initial position of the plunger 7, together with it form a throttling element, the throttling area being determined by the sum of the minimum sections of the channels in this section.

The dependence of the cross section area of the throttle channels on L1 (the distance from the initial position of the plunger) is found by solving the equation system

- T,

 (S

1 - 1 ss

S.

(2)

- T

min

 one

h

U p

(3)

 R

BMK

 L1

TMCXUC - TMWH S l 1 max

 s

(four)

AR -gQ - -r

R 8L

5G-

dp (L + 1,) --T-

with

cT-PL

de lr - differential pressure at the inlet and outlet of the automatic regulator, N / m, since the pressure at the inlet 10 is much less than the pressure at the outlet 30 11, then we assume that the area of the piston of the hydraulic cylinder, the working load on the cylinder, n; 35 volumetric flow oils through the device, m / s; the area of the plunger regul STQ

pl

liСRLЧЛ1тора, M;

initial compression of the regulator spring 40, m; spring stiffness coefficient, N / m; regulator throttle hole radius, m; 45 the length of the throttling channel, in our case, is approximately equal to the length of the grunger, m;

viscosity coefficient, 50 kg / ms;

distance from the initial position of the plunger, m

Denote the maximum and minimum load on the cylinder T, o, ksI T, respectively, we find the spring constant C and the dependence of R

from 41

20

ITdp

8gL5

o /.,. j.

(five)

five

0 5

0 5

0

five

The throttle channels 6 of the regulator 1 are designed in such a way that the dependence of the radius R on -L, determined by expression (5), provides in the system at any load a constant differential pressure Lp const (see Fig.7). The stiffness of the spring 17 of the check valve 2 is designed so that the ball 16 moves a certain distance depending on lr and does not prevent the passage of the working medium through the throttle channels 15 (see Fig.2).

An example of the calculation of the parameters of the locking and regulating device for the hydraulic system for lifting the trailer body 2PTS-4:

 5-ton 5-10 N is the mass of the moving part of the body;

T min 1 t 1 10 N is the mass of a part of a body, without a load;

S 113 Hume

2

piston area of the hydraulic cylinder.

The volume flow rate of oil Q will be found from the considerations that on average acceptable (for safety reasons) lowering time of the trailer platform (working body) (t) corresponds to t 30 m, the working stroke of the cylinder is X 0.93 m

,, X-S 0.93-113-10 h - --- -

thirty

 3.5-10 m3 / s

accept l1 „px 0.01 m 10 mm; 5 „5 mm; 1 11.3402 kg / m s. Substituting the data into formula (5) connecting R c and 1, we get

R ....

2 Z5jlo: i

339 l 1 + 1

L 1

min

 About R

 10mm R;

2.75 Mm; 1.9 mm.

The area of the plunger S d choose from

conditions s. (8-10) 1 - RLKc (8-10) -23.7 (189.6-237) mm (4.38-4.9) mm.

Take the radius of the plunger is equal to 5 mm. Spring stiffness is determined by

R pl

way with s,

Tt

l1s (ks.

 s s 1

MEAC

 0.785-.

1000

 27.78 kg / cm.

Initial compression Tllyn spring

eleven

t - t

(KC, "MN

4 0.25 CM.

When executing throttle channels by expression (5) under the condition Q f (4p) -.const 350 cm / s, the speed of lowering the platform (working parts) is constant, independent of the load on the working cylinder, and when the undersea hydraulic system hose is open. platform (working bodies) stops.

Thus, the dependence of the throttle channel radius on the movement of the plunger for the trailer 2ПТС-4 has the form (see Fig.7)

R -g Z5iio: i.

 OZZE 41 + 1

m

ten

15

 20

WITH

I

 25

thirty

35

40

Nowadays, in mechanical engineering there is a constant need to use hydraulic systems that ensure fast lifting of working bodies and a constant slowed down speed independent of external load, as well as blocking of the lowering platform (working bodies) when an accidental break of the hose occurs.

When equipped with the proposed device, agricultural machines exclude the possibility of a sharp lowering of the platform (working bodies) in case of accidental interruption when the hose is broken, and hence the injuries associated with it.

Claims (1)

Invention Formula A hydraulic shut-off and control device containing an automatic flow regulator and a shut-off valve, characterized in that, in order to protect the platforms or working bodies from damage due to sudden shocks, stopping if the hose is accidentally broken, the automatic flow regulator is designed as a housing with throttle channels made in the form of longitudinal spline grooves of variable length along the section, and with a spring-loaded plunger placed in its axial channel, with a shut-off valve and an automatic flow regulator installed in series between the hydraulic cylinder and distributor. L / ( (ri.5 FIG. 2 at at  Fi & b rig 7