BE1029904A1 - Control arrangement for controlling a hydraulic cylinder for adjusting a harvesting attachment - Google Patents

Abstract

A hydraulic control arrangement (116) for controlling a hydraulic cylinder (114) for adjusting a header (20) relative to a harvesting machine (10) comprises an electronic control unit (70), a tank (202) for receiving hydraulic fluid, a pump (110) for providing pressurized hydraulic fluid, a first valve assembly and a second valve assembly. The control unit (70) is signal-connected to the valve assemblies and configured to selectively connect the pump (110) or the tank (202) to the hydraulic cylinder (114) via the first valve assembly in a first mode of operation and to selectively connect the pump in a second mode of operation (110) or to connect the tank (202) to the hydraulic cylinder (114) via the second valve arrangement.

Description

1 BE2022/0055

Control arrangement for controlling a hydraulic cylinder for

Adjustment of a harvest header

Description

The invention relates to a hydraulic

Control arrangement for controlling a hydraulic cylinder for

Adjustment of a header in relation to a harvesting machine, comprising an electronic control unit, a tank for receiving hydraulic fluid, a pump for providing pressurized hydraulic fluid, a first valve arrangement and a second

Valve assembly, wherein the control unit is signal-connected to the valve assemblies and configured, optionally the

Pump or tank in a first mode of operation over the first

To connect the valve arrangement to the hydraulic cylinder and in a second operating mode to connect either the pump or the tank to the hydraulic cylinder via the second valve arrangement, and a harvesting machine equipped therewith.

State of the art

Self-propelled harvesters include next to that

Body of the actual harvesting machine, which is supported on ground engaging means such as wheels and / or crawlers on the ground, also a header with which they record the crop to be processed from a field. The header is through a

Infeed conveyor connected to the body of the harvester. To the

Height adjustment of the header are actuators in the form of (usually arranged on both sides of the intake conveyor) hydraulic cylinders, which the intake conveyor and thus the

Header with a transverse to the forward direction oriented,

2 BE2022/0055 rotate horizontal axis. This axis usually coincides with the

Axis of rotation of a conveyor or a crop processing device (e.g. tangential threshing drum of a combine harvester or

chopper drum of a forage harvester) of the harvesting machine.

In the prior art, various operating modes are provided for controlling the height of the header, which usually include a contact pressure control and a position control. With the contact pressure control, the cylinders are subjected to a certain pressure (which can usually be specified by the operator of the harvesting machine or automatically based on the respective harvesting attachment), so that the harvesting attachment can be applied with a desired contact force on the

on the ground. With position control, the cylinders are moved to a specified position in order to guide the header at a desired height above the ground. In the

Position control, the target value of the height of the header above the ground can be specified by an operator or detected by a forward-looking sensor or read from a map and the actual value is measured by the height sensor of the header and serves as a feedback value for the height control (EP 1 269 823 A1, WO 2008/088916 A2).

Details of the hydraulics of such

Height controls are described in EP 2 520 152 A1, which is regarded as generic. There's a pump about one

Proportional valve with the piston chamber of single-acting

Hydraulic cylinder connected, which is opened in a position control mode for raising the header. A valve becomes

Header lowering open. Furthermore, a valve that can be switched on and off and a proportional pressure control valve connected in series with it are provided for controlling the contact pressure, which provide an adjustable pressure in the piston chamber of the hydraulic cylinder in the operating mode for contact pressure control.

Task

3 BE2022/0055

In said prior art, the three valves mentioned are each associated with a single mode of operation (contact pressure and position control) and are only opened when the associated mode of operation is active. That means the

Valves must be dimensioned sufficiently large so that they are able to raise and lower in a reasonable time even the largest and thus heaviest headers that are to be used with a specific harvesting machine. This applies in particular to the lowering process in the active contact pressure control, as there the pressure control valve only works with a small pressure difference between the contact pressure to be regulated and that in the cylinder

load pressure works and in this operating state the flow is smaller than with a large pressure difference due to the design. This is more common when fitting a relatively light header, such as a pick-up on a forage harvester. However, it also applies to heavy attachments when lowering in the headland.

This can lead to crops being left on the field because the header is being guided too high. analogues

Problems can arise with the position control, since the lowering valve provided for lowering the harvesting attachment also has to be adapted there to the lightest harvesting attachment that can be coupled to the harvesting machine. In order to avoid these problems, the experienced pilot steers

In addition, the operator manually actuates a pressure-controlled pick-up, and in some cases also anticipates the lowering valve in order to speed up the lowering process. This is also the case when using a heavy green cuttings system with pressure control

problem that the lowering process mainly on the last

centimeters too slowly. This leads to delays

Lowering the header when driving into the area to be mowed

stock or too high a bleed position.

The object on which the invention is based is seen in a height control for a header

4 BE2022/0055

To provide a harvesting machine in which the disadvantages mentioned are not to be expected or are to be expected to a reduced extent.

Solution

This object is achieved by the teaching of

Claims 1 and 7 solved, wherein in the further

Claims features are listed that further develop the solution in an advantageous manner.

A hydraulic control arrangement for controlling a hydraulic cylinder for adjusting a harvesting attachment in relation to a harvesting machine includes an electronic one

Control unit, a tank for holding hydraulic fluid, a

Pump for providing pressurized hydraulic fluid, a first valve assembly, and a second valve assembly. The

Controller is signally connected to the valve assemblies and configured to selectively (i.e. sequentially) operate the pump or tank in a first mode over the first

To connect the valve arrangement to the hydraulic cylinder and in a second mode of operation optionally (i.e. the pump or the

To connect the tank to the hydraulic cylinder via the second valve arrangement. It is proposed that the control unit be configured to additionally connect the pump or the tank to the hydraulic cylinder via the second valve arrangement in the first operating mode and/or to connect the pump or the tank to the hydraulic cylinder additionally via the first valve arrangement in the second operating mode connect.

In this way one avoids the disadvantages mentioned without much effort, namely only by reprogramming the control, by using the other (first or second)

Valve assembly shared to control the hydraulic flow through the

To increase control arrangement and thus the header

need to be able to adjust faster than before.

The first mode can be a

Be support pressure control mode, while the second mode

Position control mode can be. 5 The first valve assembly can thus a

Pressure control valve and an on and off valve, wherein the on and off valve is connected between the hydraulic cylinder and a first connection of the pressure control valve and the

Pressure control valve is arranged to connect the first port either to the tank or an outlet of the pump.

The second valve assembly can be a lift valve and a

Include lowering valve, wherein the lifting valve between the outlet

Pump and the hydraulic cylinder is connected and the lowering valve is connected between the hydraulic cylinder and the tank.

The pressure in the hydraulic cylinder can by means of a

Sensors can be detected and the controller configured, the second

To activate the valve arrangement in the contact pressure control mode if there is a difference between a detected setpoint and actual value of the

Pressure in the hydraulic cylinder exceeds a threshold. Analogously, the position of the header can be detected by means of a sensor and the control can be configured, the first

Activate the valve assembly in the position control mode if there is a difference between a detected setpoint and actual value

Header position exceeds a threshold.

The control arrangement described can be at any

Harvesters, such as forage harvesters and combines, are used in conjunction with any header. As

Harvesting attachment according to the present invention can also be a

Mowing device can be considered that is described above

Control arrangement with a to be regarded as a harvesting machine

Carrier vehicle, e.g. a farm tractor or a self-propelled vehicle, and is attached to the front, side or rear. The crop does not necessarily have to be in the

6 BE2022/0055

Harvesting machine are promoted. In other words, it can

Control arrangement in general on agricultural machines and

Devices are used that use pressure and position controls for actuating processes of functional elements or attachments.

example

An exemplary embodiment of the invention is explained with reference to the illustrations. Show it:

1 shows a schematic side view of a harvesting machine with a header, and

Fig. 2 shows a schematic of the control arrangement for measuring the contact pressure or

Height control of the header of the harvesting machine of Figure 1.

In Figure 1, a self-propelled harvester 10 in

Form of a forage harvester shown in a schematic side view.

Harvester 10 is built upon a frame 12 supported by front driven wheels 14 and steerable rear wheels 16 . The harvesting machine 10 is operated from a driver's cab 18 from which a harvesting attachment 20 in the form of a pick-up (so-called pick-up) can be seen. by means of

Harvester 20 recorded from the ground crop, z. B. grass or the like is a feed conveyor 22 with

Feed rollers, which are within a feeder housing 24 at the

Front side of the harvesting machine 10 are arranged, one below the

Driver's cab 18 arranged chopping drum 26 supplied that it in

Cooperation with a shearbar 102 chopped into small pieces and a conveyor 28 abandons it. The crop leaves the harvesting machine 10 to a transport vehicle traveling alongside via an ejection chute 30 which can be rotated about an approximately vertical axis and whose inclination can be adjusted

Directional information, such as sideways, down and up, on the

Forward direction V of the harvesting machine 10, which runs to the right in FIG.

7 BE2022/0055

The drive of the chopping drum 26 is based on a pulley 48 via an angle gear with a

Internal combustion engine 32 is connected via a drive belt 50 which has a pulley 54 for driving the chopper drum 26 and a

Pulley 52 for driving the conveyor 28. A

Grinding device 100 is used to grind the chopper

Chopping drum 26. In addition, a metal detector 108 is provided in the lower, front feed roller, which may be used to quickly stop the

Feed conveyor 22 is used, and one with an electronic

Control 70 (ECU) coupled operator input device 98 in the

Driver's cabin 18.

The collection housing 24 with the collection conveyor 22 is as

The whole thing can be pivoted about the axis of rotation of the chopper drum 26 . For this purpose, a hydraulic cylinder 114 is provided on each of its two sides, with one end on the frame 12 of the harvesting machine 10 and the other

End at the front of the feeder housing 24 articulated.

A hydraulic control assembly 116 of

Hydraulic cylinder 114 is shown in FIG. 2, which is based on the prior art according to EP 2 520 152 A1, the disclosure of which is based on

Reference is included in the available documents. The hydraulic control assembly 116 is configured to

Piston chambers of the hydraulic cylinders 114 under pressure

Supply hydraulic fluid to extend it in this way.

When the hydraulic cylinders 114 extend, it pivots

Feed housing 24 upwards and lifts the header 20 further up over the ground. Similarly, when the control assembly 116 discharges hydraulic fluid from the piston chambers of the hydraulic cylinders 114 into a tank 202, the hydraulic cylinders 114 retract and the retractor housing 24 pivots downward and the

Header 20 descends towards the ground.

Figure 2 shows a hydraulic control assembly 116 with a closed hydraulic circuit for raising and lowering

8 BE2022/0055 of the feeder housing 24. A hydraulic pump 110 is through the

Internal combustion engine 32 rotated. The pump 110 has an adjustable displacement and has to a control port 112 which is connected to a hydraulic control line 200 which the

Pressure build-up of the pump 110 controls depending on the pressure applied to the control line 200. The greater the pressure on the control line 200, the greater the adjusted pressure of the pump 110. The hydraulic flow provided by the pump 110 is determined by the cross section opened by the controlled valves.

The inlet of the pump 110 is in fluid communication with a tank 202 for withdrawing fluid therefrom. The outlet of

Pump 110 is in fluid communication with the

Input connection of a pressure equalization valve 204. A hydraulic

Lift valve 206 is between the cylinders 114 and the

Pressure compensation valve 204 arranged. In the line which the

Outlet of the lift valve 206 and the piston chambers of

Connecting hydraulic cylinder 114, a check valve 208 is arranged, which allows passage of hydraulic fluid from the lift valve 206 into the cylinder 114 and a return flow from the

Cylinders 114 in the lift valve 206 prevented.

A second check valve 210 connects a line connecting the inlet of the check valve 208 and the outlet of the

Lift valve 206 connects to a sensing port of the pressure equalizing valve 204, with the hydraulic control line 200. The second

Check valve 210 allows flow of hydraulic fluid from the outlet of lift valve 206 and prevents flow from the

Control line 200 into the inlet of the check valve 208, the

Sensing connection of the pressure compensation valve 204 and the outlet of the

lift valve 206.

A hydraulic valve designed as a proportional valve

Lowering valve 212 is arranged between the piston chambers of the cylinders 114 and the tank 202 to hydraulic fluid from the

to allow cylinders 114 into tank 202 if that

9 BE2022/0055

Lowering valve 212 is energized. The header 20 is then lowered solely by the action of gravity. When the lowering valve 212 is not energized, it blocks the flow of hydraulic fluid from the cylinders 114 into the tank.

The lowering valve 212 and the lifting valve 206 are electrically connected to the controller 70, which in turn is connected to the

Operator input device 98 in the driver's cab 18 is connected.

The operator can thus use the operator input device 98 (in a position control operating mode) to cause the header 20 to be raised and lowered, for which purpose the controller 70

Lifting valve 206 or the lowering valve 212 opens and thus the

Header 20 is raised or lowered.

A control valve 216 is between the hydraulic

Control line 200 and the tank 202 arranged. The control valve 216, shown here as an orifice, drains the control line 200 when the lift valve 206 is closed (i.e., when the operator is not attempting to raise the header 20) until the in FIG

Control line 200 prevailing pressure is almost zero. As long as that

pressure in the control line 200 is close to zero, the am

Control terminal 112 of the pump 110 pending control signal im

is essentially eliminated and the specific displacement of the pump 110 is reduced to almost zero in response. Since the pump 110 is not required to raise the header 20, the

Pump 110 still provides a small amount of pressure, but requires little

drive energy.

When the operator lifts the header 20 via the operator input device 98 and the controller 70, it opens

Lift valve 206, which then the under low pressure, provided by the pump 110 fluid to the second

Check valve 210 applies, which in turn this low

Pressure applied to the control line 200. As a result, the pressure in the control line 200 increases slightly and the specific displacement of the

Pump 110 increases slightly. This increases the pressure at the outlet

10 BE2022/0055

Pump 110 to, thereby over the lift valve 206 and the second

Check valve 210 and the pressure in the control line 200 increases. This pressure feedback loop over the second

Check valve 210 gradually increases the specific

Displacement of the pump 110 to that present at its outlet

pressure reaches the static pressure in the cylinders 114 and that

Check valve 208 opens and the cylinder 114 fills. This creates a certain time delay between the actuation of the operator input device 98 and the lifting of the

harvest header 20.

The hydraulic control arrangement according to FIG. 2 comprises further elements, a contact pressure regulation and a

Enable control of the pump 110 via a check valve 306 in order to reduce the reaction time when controlling the

Lift valve 206 to shorten. This is a one-and-one

shut-off valve 302, a pressure control valve 304, the check valve 306 and a pressure sensor 308. The controller 70 is connected to the on-off valve 302 to open or close it. The controller 70 is connected to the pressure control valve 304 to a controllable, desired at its output

to achieve pressure. In addition, the controller 70 with a

Pressure sensor 308 connected, which provides a signal indicative of the pressure in the cylinder 114.

The on and off valve 302 is on one side with the cylinder 114 and the check valve 208 and on the other

Side connected to the pressure control valve 304. second and third

Ports of the pressure control valve 304 are selectively connected to a first port of the pressure control valve 304, depending on whether the pressure commanded by the controller 70 is greater or less than the current pressure at the first port of the

Pressure control valve 304 is. The controller 70 controls this

Pressure control valve 304 so that when the pressure present at the first port is less than a commanded pressure, the first

Connection of the pressure control valve 304 via a check valve 324

11 BE2022/0055 and a line 320 is connected to the pump 110 until a pressure commanded by the controller 70 is present at the first connection.

Similarly, the first port is connected to the tank 202 via a line 322 as long as the pressure at the first port is greater than a pressure commanded by the controller 70 . The first port of the pressure control valve 304 is coupled to the inlet of the check valve 306 whose outlet is connected to the hydraulic control line 200 . Thus the pressure is at the first connection of the

pressure control valve 304 to the control line 200 if the

Check valve 306 is open. This will suppress the

Pump 110 adjusted so that the pressure at its outlet is slightly greater than the pressure in the control line 200.

In the pad pressure control mode (also known as

swim mode) is hydraulic

Control arrangement 116 set up to provide a substantially constant pressure in the hydraulic cylinders 114.

This mode of operation is used when the header 20 is to be guided over the ground with a specific tracking force. This constant pressure is achieved by the controller 70 switching on and off

Shut-off valve 302 is energized and thus connects the cylinder 114 directly to the pressure control valve 304. Here, additional fluid is supplied from the pump 110 by the pressure control valve 304 via the on and off valve 302 when the

Header 20 on uneven, rising in the forward direction

ground moved up. Similarly, the pressure control valve 304 on uneven, sinking in the forward direction, resulting in

Retracting the cylinders 114 directs excess hydraulic fluid from the cylinders 114 via the on-off valve 302 via the

Drain line 322 into tank 202 to maintain pressure. The non-return valve 306 and the control line 200 ensure that the pump 110 only provides the pressure required in each case, without a time delay when lifting.

In the second, already described above

Position control mode (height control) of the header 20 is

12 BE2022/0055 the on/off valve 302 is closed. By the

Pressure control valve 304, which also provides a certain pressure on the control line 200 via the check valve 306 in the height control mode, even when the lift valve 206 is closed, is the above-mentioned disadvantage of the time delay of the only from the

Valves 204 and 206 constructed arrangement when lifting the

Harvesting attachment 20 avoided. When the valve 302 is closed, the pressure control valve 304 is used to set a pressure that is slightly lower than the load pressure. The pump 110 will set the pressure to this value - as an elevated standby pressure - and then be faster on a lift because of the time it takes to build up pressure from the normal low

standby or other lower load pressure of another

Consumer is shortened. You could possibly refer to this

Procedure for the pressure control for lighter headers and the position control for heavy headers at least for one

Do not lift the header into the transport position, as this causes unnecessary hydraulic power loss.

Up to this point, the description corresponds to the status of

Technology according to EP 2 520 152 A1, with the exception that according to

Figure 2 also the lifting valve 206 and the lowering valve 212 with the

Controller 70 are connected and controlled by them. Again, the prior art only opens on/off valve 302 and closes lift valve 206 and lowering valve 212 in the first (pressure control) mode of operation, and closes the on/off valve in the second (position control) mode of operation 302 is always closed and, if necessary, the lifting valve 206 or the

Lowering valve 212 can be opened. This has the disadvantage that, for example, the dimensioning of the passage opening of the valve 212 determines how quickly a header 20 can be lowered.

Since the lowering valve 212 is usually dimensioned so large that a relatively heavy header 20 with appropriate

Speed is lowered, resulting in lighter

Headers 20, like the pick-up shown in Figure 1, the disadvantage that the header 20 drops too slowly because of his

Weight in the cylinders 114 resulting pressure is quite low. Man

13 BE2022/0055 could now increase the passage opening of the valve 212, but this has the disadvantage of higher manufacturing costs. In addition, heavy 20-row headers, such as 12-row (9 m

working width) drop too quickly and hit the ground almost unchecked, which is also undesirable. Similar problems can be found in the

position control mode occur during lift by the lift valve 206, as does the bearing pressure control mode by the

Pressure control valve 304.

It is therefore proposed that the controller 70 be configured and programmed not only that, in the position control mode, upon a commanded lowering of the header 20

To open lowering valve 212, but also the input and

To open shut-off valve 302 and the pressure control valve 304 in the in

Figure 2 to spend position shown, in which it is the one and

Shut-off valve 302 connects to tank 202 via line 322 .

As a result, said problem can be avoided and a relatively light harvesting attachment 20 can be lowered sufficiently quickly.

Furthermore, the controller 70 can be configured and programmed not only that in the position control mode with a commanded raising of the header 20

To open the lifting valve 204, but also to open the on and off valve 302 and to bring the pressure control valve 304 into the position not shown in FIG

Shut-off valve 302 connects to pump 110. As a result, the problem mentioned can be avoided and a relatively heavy harvesting attachment 20 can be lifted sufficiently quickly.

In the position control mode, the controller 70 can act as a

scheme work. For this purpose, a sensor 310 is provided for detecting the height of the harvesting attachment 20 above the ground (cf., for example,

EP 1 911 342 A2 for a maize header), which reports back to the controller 70 an actual value of the height of the header 20 above the ground. The operator input device 98 or other

Sensor, for example, the height of the crop and / or

14 BE2022/0055 anticipating the ground contour are used by the controller 70 as a

Target value for the height or the angle of rotation of the feeder housing 24 about its axis of rotation. In a manner known per se controls the

Control 70 then the lowering valve 212 or the lifting valve 206 to control the hydraulic cylinder 114 in the sense of an adjustment of the actual value to the setpoint. Should the difference between target and actual value be greater or greater than a certain (first or second) threshold, indicating that the

If the lowering valve 212 or the lifting valve 206 alone is not able to fill or empty the hydraulic cylinder 114 sufficiently quickly, the controller 70 would open the on/off valve 302 in the manner described above and move the pressure control valve 304 to a suitable position, i.e. the in and

Connect shut-off valve 302 to the outlet of the pump 110 or the tank 202.

If the header 20 no suitable sensor for

having height above ground sensing, such as the pickup shown in Figure 1, the sensor 310 may also measure the angle of the

Capture housing 24 relative to the frame 12. To this

Way, the height of the header 20 can be adjusted with a predetermined or fixed speed, regardless of its

Weight, and if necessary, in the manner described above, open the on/off valve 302 and bring the pressure control valve 304 to an appropriate position, i.e. connect the on/off valve 302 to the outlet of the pump 110 or the tank 202.

Analogously, there is the possibility in which

Support pressure control mode based on the pressure detected by pressure sensor 308 in hydraulic cylinders 114 when a threshold value of an upward deviation from the desired pressure is exceeded by the controller 70 to open the lowering valve 212 and/or when a threshold value of a downward deviation from the desired pressure is overwritten by the controller 70 to open the lift valve 206. This allows situations in which the header 20 is subject to a sudden change in position, e.g

Driving over a bump or driving through a depression can be compensated for more quickly than before

Claims (7)

16 BE2022/0055 PATENT CLAIMS 1. Hydraulic control arrangement (116) for controlling a hydraulic cylinder (114) for adjusting a header (20) relative to a harvesting machine (10), comprising an electronic control unit (70), a tank (202) for receiving hydraulic fluid, a pump (110 ) for providing pressurized hydraulic fluid, a first valve assembly and a second valve assembly, wherein the control unit (70) is signal-connected to the valve assemblies and configured to selectively operate the pump (110) or the tank (202) in a first mode over the first to connect the valve arrangement to the hydraulic cylinder (114) and in a second operating mode to optionally connect the pump (110) or the tank (202) to the hydraulic cylinder (114) via the second valve arrangement, characterized in that the control unit (70) is configured , the pump (110) or the tank (202) in the first operating mode additionally via the second valve arrangement with the hydraulic cylinder (114) and/or in the second operating mode the pump (110) or the tank (202) additionally via the to connect the first valve assembly to the hydraulic cylinder (114). 2. Control arrangement (116) according to claim 1, wherein the first operating mode is a bearing pressure control mode and/or the second operating mode is a position control mode. 3. Control arrangement (116) according to claim 2, wherein the first valve arrangement comprises a pressure control valve (304) and an on/off valve (302), the on/off valve (302) between the hydraulic cylinder (114) and a first port of the pressure control valve (304) is switched and the pressure control valve (304) is arranged to connect the first connection either to the tank (202) or to an outlet of the pump (110). 4. Control arrangement (116) according to claim 2 or 3, wherein the second valve arrangement comprises a lift valve (206) and a 17 BE2022/0055 lowering valve (212), the lifting valve (206) is connected between the outlet of the pump (110) and the hydraulic cylinder (114), and the lowering valve is connected between the hydraulic cylinder (114) and the tank (202). 5. Control arrangement (116) according to one of claims 2 to 4, wherein the position of the header (20) can be detected by means of a sensor (310) and the controller (70) is configured to activate the first valve arrangement in the position control mode if a Difference between a detected setpoint and actual value of the position of the header (20) exceeds a threshold. 6. Control arrangement (116) according to one of claims 2 to 5, wherein the pressure in the hydraulic cylinder (114) can be detected by means of a sensor (308) and the controller (70) is configured to activate the second valve arrangement in the contact pressure control mode if a Difference between a detected target and actual value of the pressure in the hydraulic cylinder (114) exceeds a threshold value. 7. Harvester (10) with a control assembly (116) according to any one of the preceding claims.