DE3210519A1 - HYDRAULIC SYSTEM - Google Patents

Description

R. VSS]

February 18, 1982 Wd / Kc

ROBERT BOSCH GMBH, 7OOO Stuttgart 1

Hydraulic system
State of the art

The invention is based on a hydraulic system the genre of the main claim. In such a known system, if only a single-acting Cylinder is connected to the line network via the line coupling, in the "lowering" operating state that all of the pressure medium conveyed by the pump can be drained via a pressure relief valve. this means not just a loss of energy, but also due to the flow resistance the oil is also heated in an undesirable manner at the pressure relief valve.

Advantages of the invention

The hydraulic system according to the invention with the characteristic Features of the main claim has the advantage that when a simple to the hydraulic network acting working cylinder is connected, in the operating

Λ-,

state "lowering" a direct, resistance-free relief the pump to the tank is possible. This means a noticeable saving in energy.

Through the measures listed in the subclaims Advantageous developments and improvements of the features specified in the main claim are possible.

drawing

An embodiment of the invention is shown in the drawing and explained in more detail in the following description. 1 shows a schematic representation of a hydraulic system, FIG. 2 shows a view of a device used in the system, FIG. 3 shows a section along III-III according to FIG. 2, FIG. K shows a further variant of a device used in the system in a longitudinal section.

Description of the embodiment

A pump 10 sucks from a reservoir 11 pressure medium to and displaces it in a line 12, the 'h / 3-way valve leads to a thirteenth This can take the switch positions I to III. A pressure relief valve 11+, which is connected to the container 11, is connected to the delivery line 12.

A first line 16 leads from the outlet of the directional control valve to a line coupling 17 and a second line 18 to a second line coupling 19A 2/2-way valve 20 is connected to line 18,

-S- _t

via a line 21 from the line 18 to the container 11 leads. The return line 22 from the directional control valve 13 is also connected to the line 21.

A line 2 \ is connected to the first line coupling and leads to the pressure chamber 25 of a single-acting working cylinder 26.

The line coupling 19 can be closed by a flap 27 which is fixed to a housing Console 28 is pivotably arranged. At the other end of the lever-like flap 27 engages a spring 30, which the flap 27 presses on the line coupling. The directional control valve 20 is in operative connection with the flap 27 and can be moved from this to one of its two switching positions I or II, where I is a blocking position is.

If the consumer is a double-acting working cylinder, it leads from the line coupling 19 a line 31 shown in dashed lines to the other pressure chamber of the working cylinder, which, however, is not is further designated.

It is assumed that - as shown in Figure 1 to the line coupling 17 via the line 2U a simple acting working cylinder 26 is connected. In the switching position III of the directional control valve 13, pressure medium arrives Via line 12, directional control valve 13 ', line 16, line coupling 17 and line 2U to the pressure chamber 25 of the working cylinder 26. Its piston velvet; Piston rods are extended. Since no line is connected to the line coupling 19,

17887

the line coupling is closed by the flap 27. If a double-acting cylinder is provided, the flap 27 is folded up and attached to the Line coupling 19 is connected to line 31. By opening the flap 27, the directional control valve 20 brought into its blocking position I, so that there is no longer any connection from line 18 to line 21.

If the piston of the single-acting working cylinder 26 connected to the line coupling 17 is to be lowered, the directional control valve 13 is brought into its switching position I. The flap 27 is closed, the directional valve 20 is in its switching position II. Now pressure medium can flow out of the pressure chamber 25 of the working cylinder via the lines 2U, 16 as well as the directional valve 13 and the line 22 into the container. The pressure medium that continues to be conveyed by the pump now flows via line 12 and directional control valve 13 into line 18 and from there via directional control valve 20 and line 21 to the container without any noticeable resistance. In known systems, this pressure medium had to be drained via the pressure relief valve lh , which meant a significant loss of energy.

If a double-acting working cylinder is arranged, this difficulty does not arise, and the directional control valve 20 is in its open flap 27 Locking position I; the flow position II is not now needed.

The embodiment of Figures 2 and 3 shows a practical embodiment. The flap 27 is on one Axle 37 is attached and is pressed onto line coupling 17 by means of two torsion springs 35, 36. To the

UBB?

The housing 38 accommodating the flap 27 is attached to a housing 39 which has a blind bore UO in which a control slide 1 + 1 is guided in a tightly sliding manner. This is pressed with its extension k2 by the force of a spring 1 + 3 arranged in the blind hole Uo against the flap 27. The control slide 1 + 1 has an elongated annular groove kk , in the area of which two transverse bores 1 + 5, h6 into the blind hole 1 +0 open when the flap 27 is closed. The pressure medium flowing in the line 18 can then - as described above - flow via the transverse bore 1 + 5, the annular groove 1 + 1 +, the transverse bore 1 + 6 and the line 21 to the container. If the flap 27 is folded up for the purpose of connecting a line to the coupling 17, then the control slide 1 + 1 interrupts the connection between the two transverse bores 1 + 5, h6.

The embodiment according to FIG. K shows a modification of that according to FIGS. 2 and 3. Here, under the force of the spring 1 + 3, a plunger 50 rests against the flap 27. The part of the plunger located in the blind bore 1 + 0 is conical Area 51 as well as a cylindrical area 52 following this, on which, when the flap 27 is closed, the plunger 53 of a seat valve rests. In this operating state, the seat valve is open. After opening the flap for the purpose of connecting a line to the coupling 17, the plunger 53 reaches the end of the conical area 51, whereby the seat valve 5! + Is closed. In this state, no pressure medium can flow from line 18 to line 21, as described at the beginning.

Blank page

Claims (3)

R. 1768 7 18.2. 1982 Wd / Kc ' ROBEET BOSCH GMBH ₅ TOOO Stuttgart 1 Expectations M ΛHydraulic system with a single or double acting Working cylinder, to which the pressure medium conveyed by a pump via a multi-way valve and this downstream, Line couplings arranged in the supply lines as well as lines connected to this, characterized in that one of the line couplings (17 j 19) can be closed by means of a flap (27) which is operatively connected to a control valve (20) is, and that via the control valve (20) a connection (12, 18, 21) from the pump via the multi-way, valve (13) and the line (18) leading to the other line coupling to the container can be produced. 2. Plant according to claim 1, characterized in that the control valve is a 2/2-way valve. 3. Plant according to claim 1 and / or 2, .L ^ characterized by, that the flap (27) can be actuated by at least one spring (30, 35 »36). 321051 _ ρ H. System according to one of Claims 1 "to 3, characterized in that the control valve (20) is designed as a control slide (h 1) which, under spring force (lf-3), rests against the flap with an extension (^ 2). 5. Plant according to one of claims 1 to 3, characterized in that that the control valve is used as a seat valve (5 * 0 is designed, which can be actuated by a plunger resting on the flap (27) by spring force (1 * 3).