DE2301648A1 - HYDRAULIC CONTROL DEVICE - Google Patents

Description

12/12/1972 My / Gü

Attachment to

Patent and

Utility model registration

ROBERT BOSCH GMBH, STUTTGART

Hydraulic control device ;

The invention relates to a hydraulic control device for at least two consumers, each of which has a control valve is assigned, each of which in a first digit " ment separates one side of the consumer from a channel serving for the inflow and return flow and in a second position with it it connects, and with a pre-selector valve connected upstream of all control valves, the one connected to an inlet first connection, a second connection connected to a return and a third connection connected to the channel and has at least a first and a second switch position in which the channel with the return or is connected to the inlet.

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It is "already known such a control device the density to control two single-acting "consumers Seat valves and a common preselector valve are provided. In order to achieve a double-acting function, the seat valves must be arranged twice, which makes the control device complex and expensive and requires a relatively large amount of space.

The object of the invention is to provide a control device for at least two consumers that have a valve arrangement suitable for controlling a single-acting consumer, if possible easy to train in such a way that a double-acting eunk-'tion is achieved. -

This is achieved according to the invention in that the preselection valve has a fourth connection, which via a pressure medium connection with the other side of at least one of the Consumer is connected and which in the first switching position with the first connection, in the second switching position with the second connection is connected, and that the pressure medium connection has a connection with the return flow via means influencing the pressure. -

This can be done with little effort and preferably from serially produced elements a control device for controlling a double-acting consumer are created, meets the special tightness requirements.

A double-acting puncture can be achieved particularly advantageously with both consumers if the other sides both consumers are connected to the fourth connection.

An extremely useful development results from the fact that between the inlet and the return a suction from the Return-permitting check valve is switched.

In this way, a negative pressure in the consumer can be safely prevented, or lowering due to dead weight.

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Further particularly advantageous refinements result, from the remaining subclaims, the description and the drawing.

An exemplary embodiment of the subject matter of the invention is shown in the drawing. This shows in

Fig. 1 shows a first embodiment of the hydraulic

Control device in a simplified representation,

2 shows a part of a second embodiment with a different selection valve and other pressure control means,

Fig. 3 shows part of a third embodiment with a other preselection valve.

1 shows a control device 11 for controlling a Heige cylinder 12 and a lifting cylinder 13 of a tail lift, not shown in detail, of a truck. The control device 11 comprises a terminal plate 14, a receiving Vorwählventil 15 intermediate plate 16 and control valves _17} 18 receiving valve plate nineteenth

The control valves 17 »" 18 are identical to one another and are designed in the form of a seat valve. Each control valve 17 _} 18 has a closing element 21 which is held by a spring 22 in a first position 23 in which it establishes the connection between one of the inflow and return flow when a single-acting electromagnet 26 is actuated, it assumes a second position 27 in which it opens the connection. The connections 25 assigned to the control valves 17, 18 are connected to the spaces 28, 29 of the cylinders 12 and 13 are connected.

The preselection valve 15 in the intermediate plate 16 has a first connection 31, which via an inlet 32 in the connection plate 14 with a pump 33 driven by an electric motor 30

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Connection has; a second connection 3'-I- is via a return 35 relieved to container 36; a third connection 37 is available with the channel 24 of the valve plate in connection and a fourth connection 38 with a second channel 39 · This second channel 39 is in communication via a line 41 with the piston rod-side spaces 42, 43 of both cylinders 12 and 13, respectively.

The preselection valve 15 has a closing member 44 which is operated by a spring 45 loads a first switching position 46, in which the first connection 31 with the fourth connection 38 and the third Terminal 37 are connected to the second terminal 34. at Actuation of a single acting electromagnet 47 is shown in FIG a second switching position 48 can be brought into which it is the first Terminal 31 to the third terminal 37 and the second terminal

34 connects to the fourth terminal 38.

In the connection plate 14 are a securing the inlet 32 Pressure relief valve .49 and in the inlet 32 itself a first Connection 31 securing check valve 51 is arranged. Further is a check valve 52 between inlet 32 and return 35 switched, the suction of pressure medium from the return

35 permitted. In addition, the connection plate 14 has an adjustable one Throttle point 53? which are switched into a third channel 54 connecting the second channel 39 to the return 35 is. The channel 24 in the valve plate 19 is closed by a bolt 55 at one end.

The operation of the control device is as follows, where It is assumed that the tail lift on the truck has been raised and folded. The pistons of cylinders 12, 13 assume the positions shown, while the closing members 21, 44 of the control valves 17, 18 and the preselector valve 15 are in their first positions 23 and 46, respectively. The loads acting on the pistons of the cylinders 12, 13 act in relation to Fig. 1 downwards; since the spaces 28, 19 are sealed off by the closing members 21 in the poppet valve type, the

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Pistons of both cylinders 12, 13 blocked hydraulically.

To unfold the tail lift, the closing member 21 of the first control valve 17 is electromagnetically into its second position 27 moves. The pump 33 is not in operation. The tail lift will now unfold as a result of its own weight and while pressure medium from the barely 28 via the control valve 17 »the first channel 24, the non-actuated preselection valve 15 and press the return 35 into the container 36. At the same time sucks the piston of the tilt cylinder 12 pressure medium via the check valve 52, the preselection valve 15, the second channel 39 and the Line 41 into room 42. At the same time, the third Channel 5 ^ and the throttle point 53 pressure medium sucked in will.

If the truck should now stand on an inclined plane in such a way that the dead weight of the tail lift counteracts unfolding, so the piston of the tilt cylinder 12 remains in its position, although the control valve 17 is in its second position 27. Kun is also switched on the electric motor 30, and the pump 33 conveys pressure medium via the inlet 32, the preselection valve 15 »the second channel 39 and the line 41 in the room -42; at the same time, part of the pressure medium flows out. , the second channel 39 via the throttle 53 into the return 35 from «The adjustable throttle point 53 can just be adjust so that sufficient pressure is available to actuate the tilt cylinder 12. That pressure is essential lower than the normal working pressure set on the pressure relief valve 49, as is required for folding in the tilt cylinder 12 or for lifting the lifting cylinder 13 is required; it amounts to z. B. 1/7 of the normal working pressure.

To fold in the tail lift, the control valve 17 and the preselection valve 15 are brought into the second position 27 and 48, respectively and at the same time the pump 33 is switched on. The pump 33 conveys pressure medium via the inlet 32, the preselector valve 15 'the first

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Channel 24 and the control valve 17 in the space 28 of the tilt cylinder 12. The pressure relief valve 4-9 limits the working pressure. At the same time pressure medium flows out of the other Room 4-2 via line 4-1, the second channel 39, the preselector valve 15 in the return 35 · Parallel to the preselection valve a small partial flow also flows via the throttle 53 into the return 35.

With the valve arrangement consisting of preselection valve 15 and control valve 17 » which in itself only for the control of a single-acting consumer is suitable, a double-acting consumer can thus be controlled.

In a corresponding manner to the tilt cylinder 12, the Lift cylinder 13 are controlled. In the second position 27 of the second control valve 18, when the preselector valve is not actuated 15 and switched off pump 33, the tail lift can be lowered due to its own weight. By additionally switching on the pump 33, pressure medium can be conveyed into the space 4-3 and an inevitable lowering can be achieved. For lifting the tail lift the preselection valve 15. and the control valve 18 are brought into their second positions 27 and 4-8 and the pump 33 switched on.

In addition, the rooms 28, 29 can also be used at the same time Pressure medium are supplied to raise the tail lift and fold it at the same time. Simultaneous relief of the Spaces 28, 29 to the return 35 is possible, whereby the tail lift is unfolded while lowering.

2 also shows as part of a second control device 60 in a simplified representation a connection plate 61 and an intermediate plate 62, in which the same parts as in FIG are provided with the same reference numerals.

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.The connection plate 61 differs from that according to Fig. 1 by the design of the pressure-influencing means as a pressure limiting valve 63 and by the lack of a check valve between inlet 32 and return 35 · The intermediate plate 62 differs from that according to FIG. "1" through a preselection valve 64 ·, the closing member 65 of which is between the first and second switching position 4-6, 48 a third switching position Has. In the third switching position 66, the first connection is blocked, the other connections 37 »38, 34- are with one another connected .. Furthermore, a second electromagnet 67 is provided for actuating the closing member 65.

The mode of operation of the control device is only discussed to the extent that than it differs from that of the control device 11:

When unfolding the tilt cylinder 12 or lowering the lifting cylinder 13 due to its own weight, pressure medium can always be sucked directly from the return 35 into the spaces 42 and 43, since the third switch position 66 keeps this connection open. For forcibly unfolding the tilt cylinder 12 or lowering the Lifting cylinder 13, the closing member 65 is brought into its first switching position 46. The pressure relief valve determines 63 the available pressure is relatively accurate, in contrast to the throttle point with viscosity and quantity dependent Pressure fluctuations according to Fig. 1. ·

3 shows as part of a third control device 70 a connection plate 71 and an intermediate plate 72 in which the same parts as in Fig. 2 are provided with the same reference numerals:

- The connection plate 71 again has a check valve 52 for • Sucking in pressure medium from the return 35. In the intermediate plate 72, the closing element 73 of the preselection valve 74 has a third switch position 75 on, in which all connections 31, 34-, 37, 38 are locked. -. '

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The mode of operation of the control device 70 differs 2 mainly as follows: In the third position 75 of the preselector valve on the one hand and on the other hand through the pressure relief valve 63 in the third channel 54- are also the spaces 4-2 and 4-3 blocked off and thus the pistons of both Cylinder 12, 13 blocked hydraulically in both directions. Folding out and lowering of the tail lift under its own weight or forced hydraulically is carried out as with the control device according to Fig. 1 in the first switching position 4-6, the pressure during the forced actuation not by a throttle 53 but is determined by a pressure relief valve 63. When it is folded in or lifted, all of the flow back from the cylinders 12, 13 flows Pressure medium via the preselector valve 7 ^ - into the return 35 »because there is no parallel path via a throttle point.

From the above it follows that changes to the exemplary embodiments shown are possible without departing from the inventive concept to deviate. So z. B. in FIG. 1 the check valve 52 completely omitted if the throttle point 53 is designed so that. the piston of the cylinder 12, 13 the entire pressure medium over the Throttle 53 can suck. Furthermore, a control device, for. B. only one double-acting and one single-acting Control consumers.

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Claims (12)

- 9 - R. 1 2 8 O Expectations (λ ./Hydraulic control device for at least two consumers, each of which is assigned a control valve, each of which in a first position separates one side of the consumer from a channel serving the inflow and return flow and connects to it in a second position, and with a preselector valve connected upstream of all control valves, which has a first connection connected to an inlet, a second connection connected to a return and a third connection connected to the channel and at least a first and a second switching position in which the channel with the return or . Connected to the inlet, characterized in that the preselection valve (15; 64; 74) has a fourth connection (38) which is connected to the other side (42, 4-3) of at least · One of the consumers (12, 13) is connected and that in the first switch position (46) with the first connection (31) »in the second switch section Llung (48) is connected to the second connection (34), and that the pressure medium connection (39, 41) via the pressure influencing means "(53; 63) has a connection with the return (35). 2. Hydraulic control device according to claim 1, characterized in that, that the other sides (42, 43) of both consumers (12-, 13) are connected to the fourth connection (38) .. - 10 409829/0163 - 10 -. R. 1 2 8 0 3 · Hydraulic control device according to claim 1 or 2, there-. characterized in that between the inlet (32) and the return (35) there is connected a non-return valve (52) which allows suction from the return. 4. Hydraulic control device according to one of claims 1 to 3 »characterized in that the means influencing the pressure as, in particular adjustable, throttle point (53) are trained. 5. Hydraulic control device according to one of Claims 1 to 3j, characterized in that the means influencing the pressure are designed as a pressure relief valve (63). .6. Hydraulic control device according to one of Claims 1, 2 and 5 »characterized in that the control valve (17» 13) is designed as a seat valve, the closing member (21) of which is loaded by a spring (22) assumes a first position (23) and an actuating device (26) with which it can be brought into its second position (27). 7. Hydraulic control device according to claim 3 and 6, characterized characterized in that the closing member (44-) of the ■ preselection valve (15) by a spring (45) loads its first switch position (46) and by a single-acting electromagnet (47) can be brought into its second switching position (48). ■ A09829 / 0163 - 11 - - 11 - R. 1 2 8 ° 8. Hydraulic control device according to. Claim 6, characterized in that that the closing member (65) of the preselection valve (64) is a position between the first and second switching st (46, 48) has the third switching position (66), in which the third and fourth connection (37 »38) are connected to the second connection (34) and the first connection is locked. 9. Hydraulic control device according to claim 3 and 6, characterized in that the closing member (65) of the preselection valve (64) has a third switching position (75) lying between the first and second switching positions (46, 48), in which all connections (3I ₁ 34, 37 »38) are blocked. 10. Hydraulic control device according to one of claims 1 to 9j characterized in that a ■ the first connection (31) securing check valve (51) is connected. 11. Hydraulic control device according to one of claims 1 to 10, characterized in that an inlet (32) securing Pressure relief valve (49) is provided. 12. Hydraulic control device according to one of claims 1 to 11, characterized by the use for controlling the tilting and lifting cylinder of a tail lift of a motor vehicle. · J 409829/0163 Blank page