DE1776120A1 - Method and device for synchronizing control of two hydraulic reversing drives - Google Patents

Description

PATENT ANWXLTE

DR. E. WIEGAND DIPL-ING. W. NIEMANN

DR. M. KÖHLER DIPL-ING. C. GERNHARDT 1776120

MÖNCHEN HAMBURG

phone = 395 314 2000 HAMBU RG 50, 24. Sept 1968

TELEGRAMS: KARPATENT KONIGSTRASSE 2S

w. 23433/68

Howaldtswerke - Deutsche Werft Aktiengesellschaft Hamburg and Kiel, Hamburg

Method and device for synchronizing two hydraulic reversing drives.

The invention relates to a method and a device for synchronizing two hydraulic drives with reversing, rotating or rectilinear movement to each other in the same or opposite direction. One of these two spatially separated drives is either of in its movement characteristics a sequence control or controlled manually.

In such systems, the two hydraulic, separate drive points for reasons For the sake of simplification, only have one controlled pump unit, the drives (hydraulic cylinders or rotary swivel drives) connected in parallel or in series and with

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Pressurized oil fed. But because at both consumer points of the pressure oil with regard to leakage oil of the seals and the same conditions can never prevail on different loads, it is necessary to use the drive point that does not have a feedback control loop with the pump unit forms, to adjust the primary driven drive point by an additional synchronization device. It is Basically to ensure that the technical effort of the synchronization device the effort for the eventual Equipping the second drive part with its own pump unit and its own sequence control not achieved.

In hydraulically driven fin stabilizers for ships it is known that in versions that only own a pump unit, this has two separate axial piston pumps, 'those of a common Control unit can be adjusted. The pump settings for each fin drive are determined by the associated feedback control loops controlled with mechanical return by rods or ropes.

In other applications for double drives that do not work with sequential controls, dual-flow pumps or flow dividers are used, e.g. when two parallel-running pumps are driven Cylinders are used, and the parallel run is made by mechanical run comparison and automatic pressure oil drainage the faster side guaranteed. Precise speed control of the cylinder run

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is not available here.

Basically it has been customary so far, the movement of the driven drive on the controlled To transmit drive, which is mechanically for short distances by shafts or rods, for larger distances and the possibility of direct transmission by means of auxiliary energy, e.g. by electrical transmission, is carried out. Both movements are then used, as mentioned, to control two pumps, or the differences in movement (error) are used to control auxiliary valves after appropriate amplification or conversion into other types of energy.

Mechanical transmissions are only useful for short distances between the two drives, they usually require one certain arrangement of the units to be connected to one another. In addition, it is with auxiliary energy, e.g. the electrical Transmission, because of the energy conversions and reinforcements, not advantageous in terms of expenditure.

Furthermore, the use of two pumps in one pump unit is important with regard to the drive and the pump control disadvantageous compared to the use of only one pump with a higher working pressure. Furthermore, with Dual-flow pumps and parallel operation of both drives when using auxiliary bypass valves ensure precise sequential control the consumer in terms of speed and distance cannot be easily realized.

The invention is based on the object of providing two hydraulic

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Lical drives with reversing movement with a pump unit, which only has a single hydraulic pump to drive and the movement of both drives of a sequence control which has a feedback control loop with only one of these drives.

The invention is based on a method for equalization for two reversing hydraulic drives with a single hydraulic feed pump with sequence control, which only controls the movements of one of the two drives, and in which the pump and the hydraulic Drives are connected in series, and according to the invention are in asynchronism between the two drives their movement via a hydraulic control circuit generates pressure pulses through which a certain pressure is exceeded and appropriately adjustable size in the connection path of the two drives liquid volumes accordingly the synchronism error fed in or discharged.

According to one embodiment of the method of the invention The central positions of one and the other drive are used as the starting point for the generation of pressure pulses used.

According to a further embodiment of the Method of the invention each of the drives move a control piston in each direction of travel, the non-controlled Drive displaces a pre-tensioned amount of a hydraulic medium into a connecting line,

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while the control piston of the controlled drive takes up a hydraulic quantity from the line.

According to a technical embodiment of the invention, the method of the invention can be carried out in such a way that that when an appropriately adjustable pressure level in the line is exceeded, a refill valve or a filling valve is actuated, which depends on the direction of the error (lead or lag of the uncontrolled drive) the enclosed volume of the hydraulic fluid between the two drives from the pump pressure line enlarged or reduced by draining.

According to a further embodiment, the Volume compensation process for each direction of travel of the drive take place from the central positions of an oscillating movement, and during the return movement of the control piston In the middle position, the hydraulic fluid is exchanged by draining it from a chamber, e.g. via a Overflow valve.

The invention also relates to a device for carrying out the method, in particular for rotary-pivoting movements around a central axis, in which two control piston groups are each mechanically driven by one of the hydraulic drives are drivable, and each of the drives is provided with a control arm with an adjusting pin is connected, as well as a stop, whereby after each passage of the control arm one of the pistons of the control piston

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group stops and the second is taken.

The method with respect to the synchronization control loop is accordingly designed so that each of the two hydraulic drives takes two small pistons (control piston) with it on its to-and-fro path. When running through the middle position to one side, a piston is taken along with a reduction to the path of the drives and on return stopped again in the middle, after which the second piston is taken from the middle to the other side. Ever an oil chamber of the piston of a drive is with the oil of the piston of the other drive connected by a pipe. The connections of both groups of flasks are on the opposite side when the reverse movement of the drives is in the same direction, they are crossed when the drive movements are in opposite directions.

Furthermore, the corresponding via the connection line Piston assigned in such a way that one is entrained by the center of movement of the uncontrolled drive Piston displaces a small volume of oil and pushes it through the connecting line to the controlled drive; here the corresponding piston takes up a normally equal volume of oil from the center.

If both drives pass through the middle position at the same time and remain synchronized, the pressure is maintained in the connecting space between two pistons at a preload value, via a check valve from the pump unit

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is fed.

In the event of a lead error in the uncontrolled system, it would initially pass through the center earlier and continue to displace more measuring oil than can be taken up by the controlled drive. The oil pressure rises above the preload value and opens a small valve, which is connected to the connection line between the drives connected in series, until the connection volume has returned to its normal value.

A special feature of this synchronization control is the fact that the connecting line between each two pistons at the same time transmission element for the movements of the uncontrolled drive, measuring point of the synchronization error and is a control value transmitter for calibrating the running error.

A further embodiment of the method according to the invention includes the interaction of check valves and small pressure relief valves and the assignment of the refilling and draining operations for the connecting line of the in Drives connected in series.

For reasons of simplicity, the synchronization device required for precise synchronization of both drives must be implemented without being connected to the control system. It should not have any mechanical transmission parts from one drive to the other, it should also allow further distances and, as a measuring transmitter and energy carrier, the hydraulic oil and the oil

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Use the pressure of the hydraulic unit of the controlled system.

The possible uses include in particular the hydraulic actuators of fin stabilizers for Ships, the steering drives for heavy land vehicles, large tin snips and press brakes with widely spaced apart Working cylinders.

The configuration of the method and the devices are to be described below using an exemplary embodiment will.

Fig. 1 shows a circuit of the synchronization control in combination with a known series circuit of one Hydraulic pump 1 with controllable and directionally reversible oil delivery with two rotary swivel drives 2 and> (Rotary vane motors).

The sequence control for the pump 1 in connection with the controlled drive 2 is not shown, either the hydraulic auxiliary elements for pump 1, such as overpressure and suction valves etc., are missing are known.

Drives 2 and 2 are mechanical with control blocks 4 and 5 connected. These contain controlled pistons 6, 7 » 8 and 9. The pump 1 is intended, for example, to convey the pressure oil into a line Io. Then the drive 3 turns in Direction of arrow and drive 2, which is connected to drive 3 is connected by a line 11, also in his

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Free direction. The displaced return oil is returned to pump 1 via line i2. Each of the drives ? and 2 takes its consumption from the pressure gradient between lines Io and 2 2. If this is the same for both drives, for example, the pressure in lines lo, 11 and 12 is 2: 1: 0.

Taken along by the rotation of the drives;> and 2, move levers 1J3 and 14 (Figures 2 to 4) analogously and The pistons 7 and Ö slide outwards from the center. Shortly before, when running from the angular position to the putty, were dio piston chambers 13 and 16 from the working pressure of the line Io Pre-tensioned via check valves 17 and Ib. A piston chamber 19, which acts on a larger area of the piston 7, is simultaneously acted upon by the line Io via a line 2o with the working pressure.

This ensures that the piston 7 is pushed through the center into its starting position (lying on the stop 21) before it starts running. The out of the chamber 15 thereby displaced oil increases its pressure just above the bias pressure, includes a check valve 22 and escapes through an overflow valve 2J5 into a hydraulic tank 24, passing through uie drives j and 2, finally, the center in the arrow direction, the piston 8 displaces oil, while the piston Y takes in oil. A lead error from drive 3 before drive 2 increases the pressure in a line 25, whereby a spring-loaded valve 26 opens proportionally to the Koehler

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- Io -

and pressure oil from the higher pressure level in line Io reaches the lower pressure level in line 11 via check valve 17, valve 26 and line Zf. As a result, the insufficient volume of the line II is normalized again, ie the drives j5 and 2 "move away" from one another. Any overrun from drive 3 to drive 2 is not corrected in this phase. After the change in direction of the pump delivery (pressure oil in line 12 »return oil in line lo) it occurs again as flow from drive 3 before drive 2 and is then compensated from the middle of the run by actuating a valve 2Ö. This valve 28 then lets excess oil from the line 11 into the tank 24. The set pressures of the valves 23 and 29 and the valves 26 and 2b are selected so that the valves 26 and 28 respond only at a pressure slightly higher than the maximum working pressure , valves 2, 5 and 29 are again above the maximum response pressure of valves 26 and 28.

The particular advantages of this synchronization control are shown in the possibility of the second, from the control uncontrolled reversing drive even over long distances and to take with you very precisely in difficult spatial conditions. Compressibility errors of the oil in the measuring rooms and connecting lines largely avoided by pretensioning the oil. Faults that cannot be avoided due to small amounts of leakage oil from the Mefi pistons cannot add up because of the control process

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177612C

each time begins with the passage through the middle with a new basic position. The synchronization control loop also works simple components of the general oil hydraulics and is directly from the main hydraulic system with pressure energy and fresh filtered oil supplied.

Associated features of the invention are also devices for performing the method on two reversing devices Slewing drives with pivot angles of up to about - 6o °.

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Claims (1)

Claims. 1. Method for synchronizing control for two reversing hydraulic drives with a single hydraulic feed pump, which is provided with a sequence control, which is merely the movements of one of the two drives controls, and wherever the pump and the hydraulic drives are connected in series, thereby marked, that with asynchronism between the two drives their movement via a hydraulic control circuit Pressure pulses generated by the exceeding a certain and appropriately adjustable size in the connection path of the two drives, liquid volumes are fed in or drained according to the uniformity error will. 'd. Method according to Claim 1, characterized in that the cement layers of one and the other drive are used as the starting point for the generation of pressure pulses. >. Method according to one of claims 1 and <:, characterized characterized in that each of the drives moves a control piston in each direction of rotation, the non-controlled Drive a pre-tensioned amount one: -; hydraulic means displaced into a connecting line, while the control piston of the controlled drive dnc Hydraul ikmnnre only; the line picks up. i '' ") 1 BATH ORIGINAL H. Method according to one of Claims 1 to j, characterized in that? if an appropriately adjustable pressure level in the line is exceeded, a refill valve or a filling valve is actuated which, depending on the direction of the error (lead or lag of the uncontrolled drive), increases the enclosed volume of the hydraulic fluid between the two drives from the pump pressure line or reduces it by draining it. 3. The method according to any one of claims 1 to 4, characterized in that the volume equalization process takes place for each direction of the drive from the central positions of an oscillating movement and during the return movement of the control piston to the central position, an exchange of the hydraulic fluid by draining from a chamber via an overflow valve he follows. 6. Device for performing the method according to one of claims 1 to 5> in particular for rotary pivoting movements about a central axis, characterized by two control piston groups (6, 7, b, 9), each mechanically driven by one of the hydraulic drives (2 or ;>) are drivable, and a control arm (j> o or j) l) is provided on the shaft of the drives, which is connected to an adjusting pin (j2) , and a stop (21) is provided, after each As the control arm (jpo or j5l) passes, one of the pistons of the control piston group (6, 7 or 8, 9) stops and the second is taken along. 109 HU / 0822
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