DE102014115029A1 - Hydraulic control valve - Google Patents

Abstract

The invention relates to a control valve for selectively switching a plurality of hydraulic working cylinder of an agricultural working machine, in particular a harvester, with a cylindrical spool movably mounted in a housing, a plurality of arranged in the housing line connections, which connectable to a pressurized inlet, a non-return valve, and working cylinders are, wherein the spool for selecting a particular working cylinder and the at least one associated pipe connection about a longitudinal axis in a working cylinder associated angular position is rotatable, and the spool for switching the preselected working cylinder and the at least one associated pipe connection is axially adjustable. According to the invention the control valve is designed and configured such that in an axial neutral position of the spool in each angular position, a fluidic connection between the inlet and the return is connected, and that single-acting cylinder and double-acting cylinder can be actuated by the spool. The control valve allows the control of a plurality of single-acting and double-acting cylinders in any combination

Description

The invention relates to a hydraulic control valve for an agricultural machine, in particular a harvester, which allows both the actuation of single-acting cylinder and double-acting cylinder.

An agricultural work machine may be self-propelled, for example as a tractor or harvester such as a combine harvester or forage harvester. Tractors usually feature hydraulic steering in addition to working hydraulics, which are used to adjust a rear linkage and a front linkage. Power lift allows the implements coupled to the agricultural work machine to be raised or lowered to specific positions during individual operations.

In self-propelled harvesting machines, for example in the form of a combine harvester, work hydraulics are usually also provided, inter alia, for actuating a liftable and lowerable harvesting attachment arranged at the front. In addition, these harvesters usually have a mostly acting on the wheels of the rear axle steering hydraulics. In addition, if the harvester is a combine harvester and the harvesting header is a cutting unit, a hydraulic adjustment of a reel can also be part of the working hydraulics present for raising and lowering the header. With a corresponding self-propelled combine harvester, the header can first be raised at the end of the grain stock, ie at the headland, in order then to be turned over for mowing along the same stock edge. Furthermore, in a combine harvester, the swinging out and in of a discharge tube for unloading the crop can be done hydraulically as well as a circuit of the travel drive.

From the DE 1 073 783 B a control device for a hydraulic system of an agricultural machine is known in which an activation of a double-acting or two single-acting pressure cylinder by a control mechanism is optional. The control of the printing cylinder via a control cylinder in which a secured against axial control bushing and in this a displaceable in the axial direction of the control piston is rotatably guided, which is adjustable by means of a lever having a control rod. The disadvantage here is that only a double-acting or two single-acting pressure cylinder can be controlled by the control device, whereby a plurality of control devices are necessary for the operation and operation of a more extensive hydraulic system, whereby the workload of an operator is increased, as given if several control devices to operate simultaneously and to coordinate. In addition, increase by the other control devices, the manufacturing cost and maintenance.

It is therefore the object of the present invention to provide a low-cost hydraulic control valve for an agricultural work machine, which allows actuation of a plurality of single-acting working cylinders and double-acting working cylinders.

The object is achieved by the features of claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

A hydraulic control valve for selectively switching a plurality of hydraulic working cylinders of an agricultural working machine, in particular a harvester, with a cylindrical spool movably mounted in a housing, a plurality of conduit spigots arranged in the housing, which are connectable to a pressurized inlet, a non-pressurized return, and working cylinders; wherein the spool for selecting a particular working cylinder and the at least one associated pipe connection about a longitudinal axis in a working cylinder associated angular position is rotatable, and the spool for switching the preselected working cylinder and the at least one associated pipe connection is axially adjustable. According to the invention the control valve is designed and configured such that in an axial neutral position of the spool in each angular position, a fluidic connection between the inlet and the return is connected, and that single-acting cylinder and double-acting cylinder can be actuated by the spool.

The hydraulic control valve can be used to operate a plurality of single-acting and double-acting cylinder in a hydraulic system of an agricultural machine, for example, by a pump continuously a flow of hydraulic fluid, such as oil, can be promoted. The control valve is designed in the form of a hydraulic rotary slide valve with a cylindrical control slide, wherein a preselection of a certain working cylinder and the at least one associated line connection takes place by a rotational movement of the control slide about a longitudinal axis. In each case, a predetermined angular position, ie a rotation of the spool in a predetermined position with a defined angle, a particular working cylinder and its associated with at least one associated conduit connection, so that the spool and the line connections required for the actuation of the preselected working cylinder can cooperate. In the preselection of a working cylinder and the at least one associated line connection, the spool of the control valve remains in an axial neutral position. In this case, the spool is arranged relative to the housing such that a circulation of the delivered volume flow of the oil from the inlet through the control valve to the return and in particular to an oil collecting tank, whereby a non-pressurized circulation of the oil can be made possible. A circuit of the at least one conduit connection of the preselected working cylinder and thus an actuation of the working cylinder takes place by an axial displacement of the spool relative to the housing and the line connections arranged therein. In this case, the volume flow of the oil is released in the preselected line connections and / or blocked. It can be made possible in accordance with the invention in dependence on the angular position of the rotary valve both a non-pressurized circulation from the inlet to the return and a pressure build-up to the working cylinder by closing the circulation, whereby both single-acting and double-acting cylinder can be actuated by the spool. Here, the non-pressurized circulation can be closed in both axial directions to build up a hydraulic pressure to the working cylinders. This allows actuation of any combination of single-acting and double-acting working cylinders by the control valve, whereby a hydraulic system with a plurality of working cylinders can be operated by means of a single control valve. This can reduce manufacturing costs by reducing control valves and maintenance. At the same time, the operation of a corresponding hydraulic system with a plurality of working cylinders and / or other switchable hydraulic actuators can be simplified, since a plurality of functions can be switched by a single control valve and thus a single control device with an operating lever, previously, for example, by a separate Valve and control lever had to be switched.

In a preferred embodiment, the housing has on the inside a connected to the inlet annular channel, and the control slide has at least one coaxial with the longitudinal axis arranged through hole, which is fluidly connected via a transverse bore at least in the neutral position of the spool with the annular channel. Due to the configuration of the annular channel connected to the inlet and its interaction with the transverse and through holes in the axial neutral position of the spool, a non-pressurized circulation of the volume flow of the oil can be ensured. In particular, the annular channel has the advantage that in the neutral position of the circulation angle position is independent and thereby a preselection of a working cylinder can be done without the circulation is interrupted.

Particularly preferably, the spool radially on the outside fluidly connected to the pressurized annular channel longitudinal grooves, which can be connected by an axial displacement of the spool with a line connection of a working cylinder. Through the annular channel a fluidic connection of the longitudinal grooves is ensured with the pressurized inlet in each angular position. By an axial displacement of the spool, in any axial direction, the circulation of the oil can be closed and connected via the annular channel and the longitudinal grooves a fluidic connection, for example, to be acted upon by a pressure cylinder or its associated line connection. In particular, the longitudinal grooves offer the advantage that a displacement of the spool valve in both axial directions can be used to switch a working cylinder.

In a preferred embodiment, the line connections associated with a double-acting cylinder are arranged in the same angular position in the axial direction adjacent to one another. Here, the line connections without a change in the angular position by a pure axial movement along the longitudinal axis can be switched. This has the advantage that in a given angular position by the same longitudinal groove of the control spool, alternatively, a line connection or the other line connection to the inlet can be fluidly connected and thus pressurized. This has the advantage that can be reversed by a purely axial displacement of the spool, the working direction of a double-acting cylinder with low switching costs. In addition, the control slide, for example, have an annular groove to depressurize the not pressurized line connection by fluidic connection with the return.

Furthermore, it is preferably provided that a check valve-like inlet valve is provided in the housing, which is associated with a line connection of a single-acting working cylinder, and which is connectable via a longitudinal groove of the spool with the pressurized annular channel. In a single-acting cylinder only one chamber of the working cylinder can be acted upon by hydraulic pressure, so that hydraulically only one movement in one direction can be made possible. A return of the working cylinder is therefore usually by unpressurized the working cylinder, so by a fluid-permeable connection with the return, and taking advantage of gravity, for example, when lowering a simple attachment to a farm machine. Due to the longitudinal grooves, the line connection of the single-acting working cylinder can be pressurized out of the axial neutral position. In order for the pressure to be maintained, an inlet valve in the form of a check valve is provided in the line connection, which opens when connected to the inlet and at the same time closes the circulation by the hydraulic pressure.

Advantageously, the housing on the bottom side at least one connected to the line connection of a single-acting cylinder, in particular spring-loaded, lowering valve for pressureless switching of the working cylinder, which is actuated by the spool. In addition to the inlet valve, a lowering valve is provided with the line connection of a single-acting cylinder, so that the oil from the single-acting cylinder can flow through the return to the sump again. This can be done while maintaining the pressureless circulation of the oil. The bottom-side arrangement of the lowering valve has the advantage that the lowering valve can be opened by a simple axial lowering and / or a rotational displacement of the spool.

In a preferred embodiment of the invention, the spool on the bottom side at an end facing the lowering valve on at least one control cam for cooperation with the lowering valve. The bottom-side arrangement of a control cam on the, the lowering valve associated end of the spool, has the advantage that a necessary for the actuation of the lowering valve axial displacement of the spool can be kept low, so that the length of the longitudinal grooves over which the non-pressurized circulation, low can be held. As a result, a more compact design of the control valve can be made possible. In this case, a control cam for operating a plurality of lowering valves, in particular single-acting, working cylinder can be used.

In a particularly preferred embodiment of the invention, the housing is formed on the bottom side in the form of a valve plate. The valve plate is arranged concentrically and can close the housing bottom side, wherein the lowering valves can be arranged in the valve plate. This offers the advantage of simpler manufacture and assembly, in particular of the lowering valves, since they can be preassembled, for example, in the valve plate. On the valve plate can be provided on the outside to cover the lowering valves and their spring-loaded actuating mechanisms, a cover.

Particularly preferably, the transverse bores in the spool radially on the outside with the annular channel cooperating fine control notches. The fine control notches are formed in the form of edge flattening on the transverse bores with notch-shaped recesses. As a result, upon axial displacement of the spool out of the neutral position and thus closure of the circuit, a gradual reduction in the cross-section of the opening between the transverse bore and the annular channel can be made possible, thus avoiding a sudden increase in pressure, for example at the selected conduit connection and the associated actuated working cylinder can. In addition, this allows the speed of movement of a single-acting and / or double-acting working cylinder, both during pressure build-up and during discharge, to control by the fine control notches.

Furthermore, the invention relates to a control device for an agricultural work machine with a control valve as described and trained above and connected to the control valve actuator. The actuating device may comprise a control column and a tiltable and guided in a shift gate control lever for actuating the control valve.

The invention further relates to an agricultural work machine having at least one control valve and / or a control device as described and configured above.

The invention is not limited to the specified combination of the features of the independent claims and the dependent claims. In addition, there are further possibilities of combining individual features, in particular if they arise from the claims, the following description of the exemplary embodiments or directly from the figures. In addition, the reference of the claims to the figures by the use of reference numerals is not intended to limit the scope of the claims to the illustrated embodiments.

In the following, the invention will be explained by way of example with reference to the appended figures with reference to preferred embodiments, wherein the features illustrated below may represent an aspect of the invention both individually and in different combinations with each other.

Show it:

1 a schematic perspective view of a control device with a control valve according to the invention;

2 a schematic view of a shift gate with an operating lever for actuating the control valve;

3 a schematic perspective view of the control valve with the line connections;

4A , B: a partially sectioned view of a spool valve;

5 : a hydraulic schematic of the in 3 illustrated control valve;

6 a schematic sectional view of the control valve in an axial neutral position of the spool valve;

7 a schematic cross-sectional view of the control valve in the neutral position with a preselected double-acting cylinder;

8th a schematic cross-sectional view of the control valve in a first, double-acting spool position;

9 a schematic sectional view of the control valve in a second, double-acting spool position;

10 : A schematic sectional view of the control valve in a lifting spool position of a single-acting working cylinder; and

11 : A schematic sectional view of the control valve in a lowering spool position of a single-acting working cylinder.

In the figures, functionally identical components are provided with the same reference numerals.

1 shows a control device 10 for an agricultural working machine, for example a combine harvester, with a control valve according to the invention 12 and one with the control valve 12 associated actuator 14 for actuating the control valve 12 and connectable working cylinder of a hydraulic system of the agricultural machine. The control valve 12 is constructed in the form of a rotary valve, wherein a cylindrical spool 16 in a housing 18 is movably mounted. On the case 18 is a plurality of line connections 20 arranged, via which, for example, a pressurized hydraulic inlet P and connected to a reservoir pressure-free return T to the control valve 12 can be connected. In addition, can via line connections for single-acting cylinder 22 and double-acting cylinders 24 corresponding cylinder actuated with the control valve 12 get connected. For switching line connections 20 . 22 . 24 and thus for actuating a working cylinder is the spool 16 around a longitudinal axis 26 rotatable around and along the longitudinal axis 26 formed displaceable in the axial direction.

The adjustment of the spool 16 of the control valve 12 takes place via the actuator 14 , The actuator 14 has a control column 28 on, which is at least partially disposed in a driver's cab (not shown) of the agricultural machine. Inside the steering column 28 is a control rod 30 at a lower end by means of a coupling 32 with one out of the case 18 outstanding end of the spool 16 rotatably connected. At an upper, operator facing end of the control rod 30 this is with a tilting mounted control lever 34 connected. The operating lever 34 is a shift gate 36 guided movably mounted. By pivoting the operating lever 34 around the longitudinal axis 26 around there is a corresponding rotation of the spool 16 around the longitudinal axis 26 , whereby a certain, in particular by the shift gate 34 predetermined, angular position of the spool 16 is adjustable. In this angular position of the spool 16 are associated line connections 20 preselected, which corresponds for example to a preselection of a working cylinder to be actuated. The spool 16 is in the preselection in an axial neutral position, where no circuit of a line connection 20 . 22 . 24 , P, T takes place. Only by an axial displacement of the spool 16 a circuit of the preselected line connections takes place 20 . 22 . 24 , P, T, whereby a preselected working cylinder can be operated as desired. The axial displacement of the spool valve 16 is done by pressing the operating lever 34 in the radial direction, wherein the radial movement of the operating lever 34 via a tilting mechanism in an axial movement of the control rod 30 and thus the spool valve 16 is implemented.

The control valve according to the invention 12 is for switching two single-acting line connections 20 . 22 and two double-acting line connections 20 , 24 designed so that, for example, two single-acting and two double-acting cylinder can be controlled, and wherein in an axial neutral position of the spool 16 a fluidic connection between the Feed P and the return T is connected, whereby a non-pressurized circulation of the oil is made possible. Especially by the simultaneous circuit of a non-pressurized circulation of the inlet P to the return line T and a pressure build-up at a preselected line connection 24 in a certain angular position of the spool 16 allows the operation of a double-acting cylinder by an axial displacement of the spool 16 in one direction. The conceptual design of the control valve 12 allows the connection of any combination of single-acting and double-acting working cylinders. Under a working cylinder according to the invention, any other hydraulic consumer or hydraulic drive mechanism can be understood. The structure and function of the illustrated control valve 12 , which is designed in particular in the form of a rotary slide valve, corresponds to that of an 8/9-way valve, wherein the function of two 3/3-way valves and two 4/3-way valves can be mapped. The control valve 12 is designed for a hydraulic system, such as a combine harvester, with a pressure source, for example in the form of an oil pump, which promotes a continuous flow of oil.

The shift gate 36 for actuating the control valve 12 is in 2 in a plan view together with the operating lever 34 shown. The operating lever 34 is to pre-selection of line connections to be switched in an arcuate opening to an associated position movable. For switching the preselected line connections is the operating lever 34 in radially adjoining the arcuate opening openings in a switch-line connections associated position A1, A2, B2, A3, A4, B4 slidably. Positions A1 and A3 of the shift gate 34 In each case line connections A1 and A3 are assigned to which, for example, in each case a single-acting cylinder can be connected. This is done with a radially inwardly directed movement of the operating lever 34 in the position A1, a raising of the spool 16 and a pressurization of the corresponding line connection 22 , A1 and an actuation of the associated working cylinder. In the radially outwardly opposite position A1 is carried out a lowering of the spool 16 , whereby a depressurization circuit of the relevant line connection 22 , A1 and, for example, the associated working cylinder. The same takes place in the positions A3 of the operating lever 34 , Through the line connections 22 , A1, A3 can be controlled single-acting cylinder, which can be used for example in a combine for height adjustment of a mower with a cutter disposed thereon or to change the height of a reel. A lowering of the mower and / or the reel can be done by a pressureless switching of the relevant single-acting cylinder.

The positions A2, B2 and A4, B4 are respectively the line terminals 24 , A2, B2, A4, B4, for example, associated with a double-acting cylinder. The line connections A2, B2, A4, B4 for a double-acting operation, for example, of a corresponding working cylinder are in pairs (A2 and B2, A4 and B4) connected to this and are operated simultaneously. In this case, in the radially inner positions A2 and A4 of the operating lever 34 the associated line connections A2, A4 pressurized and at the same time the line connections B2, B4 depressurized. In the radially outside operating positions B2 and B4, the line connections B2 and B4 are pressurized and the line connections A2 and A4 are depressurized. By the simultaneous switching of the line connections A2, B2 and A4, B4, only the operation of a double-acting cylinder can be made possible. A double-acting control of the line connections 24 , A2, B2, A4, B4 can be used in a combine, for example, for switching a traction drive or the swinging out and / or pivoting of a Abtutrohres where an operation in both directions is required.

In 3 is a perspective view of the control valve 12 shown. The spool 16 protrudes at the head end, on one of the actuating device (not shown) facing the end of the housing 18 partially for connection to the actuator out of this. On the case 18 are radially outside along the circumference of a plurality of line connections 20 . 22 . 24 , A1, A2, B2, A3, A4, B4, P, T. There are a total of eight line connections 20 . 22 . 24 , A1, A2, B2, A3, A4, B4, P, T radially outward on the housing 18 arranged, with two line connections P, T serve the inlet and the return of the hydraulic fluid, such as oil. In addition, two single-acting line connections A1, A3, for example, for connecting single-acting cylinder, and two double-acting line connections A2, B2, A4, B4, for example, for connecting two double-acting working cylinders, provided. The pipe connections 24 , A2, B2, A4, B4, which are associated with double-acting working cylinders, for example, are in pairs in the axial direction adjacent to each other and arranged in the same angular position. This allows a compact design of the control valve 12 because the circuit for the corresponding line connections 24 , A2, B2, A4, B4 required Schaltgeometrien in the housing 18 and the spool 16 have to have only a small extent in the axial direction. The inlet P and the return T are also arranged in the axial direction adjacent to each other and in the same angular position. The pipe connections 22 , A1, A3, which can be assigned to single-acting working cylinders, are in a lower region of the housing 18 arranged, the lower portion of the housing 18 in the form of a valve plate 38 is trained. The valve plate 38 has substantially the same cross section as the rest of the housing 18 on and is concentric to the longitudinal axis 26 mounted on the bottom side. The spool 16 can be in the axial direction on the valve plate 38 be supported. The pipe connections 22 , A1, A3 of the single-acting cylinders are radially on the outside of the valve plate 38 arranged. A pressurization of the line connections 22 , A1, A3 takes place with appropriate pre-selection and switching by the spool 16 each via an inlet valve 40 which is formed in the form of a check valve for holding the built-up pressure in the working cylinder. The intake valves 40 the line connections 22 , A1, A3 are in the housing 18 , especially outside the valve plate 38 arranged. The intake valves 40 are from radially outside into the housing 18 inserted and radially on the outside by a screw plug 42 sealed. A pressureless switching of the line connections 22 , A1, A3 in each case via a, in particular spring-loaded, lowering valve (not shown), which in the valve plate 38 , in particular coaxial, can be arranged. The lowering valves are through the spool 16 actuated by an axial and / or rotational displacement to a fluidic connection of the respective conduit connection 22 , A1, A3 with the return to switch. The valve plate 38 and in particular the lowering valves 40 are bottom side by a cover 44 covered.

In 4A is a partially sectional view of the spool 16 displayed. The spool 16 has a cylindrical shape, wherein an upper connecting portion 46 for connection to the actuating device has a smaller diameter than a substantially centrally arranged control section 48 , The spool 16 is on the bottom side by a return spring 50 acted upon by an axial force through which the spool 16 after an axial displacement, in particular after actuation of a lowering valve, can be returned to the axial neutral position. The return spring 50 is over a perforated disk 52 bottom side of the control section 48 of the spool 16 supported. To actuate a lowering valve, the spool 16 bottom side, in particular on the control section 48 , at least one control cam 54 on, which at an axial displacement of the spool 16 can interact with a preselected lowering valve and this can open. Radially on the outside, the spool 16 , in particular in the control section 48 , Longitudinal grooves 56 on, which can be used, for example, to switch a pressurization of a line connection. Furthermore, the spool 16 , in particular in the control section 48 , Cross holes 58 on, through which, for example, a non-pressurized circulation of the oil can be switched. The cross holes 58 have on the outside to cooperate with an inside of the housing 18 Metering notches 60 on. The fine control notches are in the form of a around the transverse bore 58 formed around flattening formed with radial notch-shaped recesses. The Feinsteuerkerben allow for an axial displacement of the spool 16 a gradual, non-sudden closing of the non-pressurized circulation by an increasing reduction of the oil-permeable opening and thus a fine control of the circuit or the movement of a working cylinder. The cross holes 58 are in the radial direction in the spool 16 arranged and fluid permeable with within the spool 16 , in particular the control section 48 , arranged through holes 62 connected. The arrangement of the through holes 62 is in 4B in a bottom view of the spool 16 shown. About the through holes 62 and the cross holes 58 is a non-pressurized circulation of the oil in the axial neutral position of the spool 16 independent of angular position switchable. Furthermore, is the return spring side of the spool 16 , in particular in the control section 48 , a circumferential ring groove 64 formed, via which, for example, a pressureless switching a line connection 20 one, in particular double-acting, working cylinder can take place.

A hydraulic circuit diagram of the control valve described as an exemplary embodiment 12 with the line connections A1, A2, B2, A3, A4, B4, P, T is in 5 shown. In 5 is the control valve 12 switched in the axial neutral position with a substantially unpressurized circulation of the oil from P to T. The two line connections A1, A3 are designed to be single-acting and the two line connections A2, B2 and A4, B4 each double-acting. The operation of the control valve 12 will be in the following 6 to 11 each represented by a sectional drawing.

In 6 is the control valve 12 in a sectional view in the axial neutral position of the spool 16 shown in any angular position. In this case, a substantially pressure-free circulation of the oil, that is to say acted upon only with the circulating pressure, is switched from the inlet P to the return line T. The oil is thereby via the inlet P the control valve 12 supplied and in an inside in the housing 18 circumferentially formed annular channel 66 directed. In the axial neutral position of the spool 16 the ring channel acts 66 With the cross bores 58 together, allowing the volume flow of the oil through the cross holes 58 in the through holes 62 of the spool 16 arrives and is returned from there via the return T, for example, to a collection container. About the through holes 62 of the spool 16 can the areas above, connecting section side, and below, bottom side, of the control section 48 be fluidly connected to the return line T, so that a uniform pressure, in particular circulation pressure, at the spool 16 acts. Bottom side, the volume flow through the perforated disc 52 are directed, although on the control piston 16 abuts, the through holes 62 but leaves unlocked. The axial support of the spool valve 16 by the return spring 50 and the cover of the valve disc 38 with a spring arranged thereon 68 a lowering valve (not shown) by a cover 44 is also in 6 shown.

In 7 is the spool 16 shown in an angular position, which corresponds for example to a preselection of the line connections A2 and B2, which are connected to a double-acting cylinder. Here, initially only the angular position of the spool 16 by a rotation of the spool valve 16 around the longitudinal axis 26 he follows. An axial displacement is not done, so the spool 16 is still set in the neutral position. The position of the spool 16 corresponds to the arrangement of the operating lever 34 between positions A2 and B2. The volume flow entering through the inlet (not shown) continues to be via the annular channel 66 the cross bores 58 and through holes 62 supplied, so that continues to be a non-pressurized circulation from the inlet to the return (not shown) out. However, in this angular position is already a longitudinal groove 56 arranged in the axial direction between the line connections A2 and B2, via which at an axial displacement of the spool 16 a fluid-permeable circuit between the pressurized annular channel 66 and a line connection A2, B2 can take place.

At the axial displacement of the spool 16 the non-pressurized circuit is closed with increasing axial slide path, in which the transverse bores 52 no longer with the ring channel 66 can interact. By means of fine control notches (not shown) can thereby flow through the cross section between the transverse bore 52 and the annular channel 66 be closed slowly. At an axial displacement of the spool 16 upwards, in the direction of the connection section 46 , the ring channel connected to the inlet becomes 66 fluidly connected to the conduit connection A2 and at the same time the conduit connection B2 via the annular groove 64 and further bores connected to the return, so that the line connection B2 is depressurized, whereby a movement of the double-acting cylinder is made possible ( 8th ).

A reversal of the movement of the double-acting cylinder 7 and 8th is in 9 shown. This is the spool 16 in the axial direction down, from the connecting portion 46 away, shifting, taking over the longitudinal groove 56 a fluid-permeable connection between the pressurized annular channel 66 and the line terminal B2 is switched. At the same time, the pipe connection A2 becomes via the through holes 62 in the spool 16 connected to the return and so depressurized. This allows the double-acting cylinder in the opposite direction as in 8th be operated.

In 10 is the spool 16 shown in an axially displaced position for actuating a single-acting working cylinder. The angular position of the spool 16 and the operating lever 34 can correspond to the position A1, wherein the illustrated axial displacement of the spool 16 upwards by a movement of the operating lever 34 is effected on the radially inner position A1. In the position shown represents the longitudinal groove 56 of the spool 16 a fluid-permeable connection between the pressurized annular channel 66 and the spring-loaded inlet valve 40 the line connection A1 ago, the non-pressurized circulation is closed with increasing axial slide path. Due to the increasing pressure, this is opened as a check valve for holding a set pressure at the line connection A1 through the volume flow, so that the volume flow can flow through the line connection A1. The inlet valve 40 is in the case 18 arranged on the outside and is closed by a screw plug 42 stored. About a connection hole 70 , which are coaxial with the longitudinal axis 26 in the case 18 is arranged, is the inlet valve 40 connected to the line connection A1.

To depressurize the line connection A1 is the spool 16 in the in 11 shown position can be brought. The axial displacement of the spool valve 16 in the axial direction can be down by a movement of the operating lever 34 be effected in the radially outward position A1. The inlet valve assigned to the line connection A1 40 is, as in the pressureless circulation in the axial neutral position, depressurized. Due to the design as a check valve Beleibt the spring-loaded inlet valve 40 however in the closed position. The pressurized annular channel 66 becomes over the longitudinal groove 56 connected to the return and so switched a non-pressurized circuit, wherein the spool 16 axially displaced to the bottom. At the axial displacement of the spool 16 leave the unpressurized circulation open with increasing axial slide and bottom side acts on the spool 16 , in particular at the control section 48 , arranged control cam 54 with one in the valve plate 38 arranged spring-loaded lowering valve 72 together, which is fluid-permeable connected to the line connection A1. By lowering the spool valve 16 becomes the lowering valve 72 by means of the control cam 54 mechanically open, so that the line connection A1 via the lowering valve 72 can be connected to the return. In single-acting cylinders, which are depressurized, usually takes place a squeezing out of the oil from the cylinder by utilizing gravity, for example, when lowering a mower. The volume flow from the line connection A1 flows at the in 11 illustrated control valve 12 over the opened lowering valve 72 through the cover 44 and a bore, not shown in this sectional view, on the bottom side to the spool 16 and in the return.

LIST OF REFERENCE NUMBERS

10

control device

12

control valve

14

actuator

16

spool

18

casing

20

line connection

22

Cable connection of single-acting cylinder

24

Piping connection of double acting cylinders

26

longitudinal axis

28

control column

30

control rod

32

clutch

34

operating lever

36

shift gate

38

valve plate

40

intake valve

42

Screw

44

cover

46

connecting portion

48

control section

50

Return spring

52

perforated disc

54

control cam

56

longitudinal groove

58

cross hole

60

Fine control notch

62

Through Hole

64

ring groove

66

annular channel

68

feather

70

connecting bore

72

lowering valve

P

Intake

T

returns

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 1073783 B [0004]

Claims (11)

Hydraulic control valve for selectively switching a plurality of hydraulic working cylinders of an agricultural working machine, in particular a harvesting machine, into a housing (in 18 ) movably mounted cylindrical spool ( 16 ), a plurality in the housing ( 18 ) arranged line connections ( 20 . 22 . 24 ), which are connectable to a pressurized feed (P), a non-return (T), and working cylinders, wherein the spool ( 16 ) for preselecting a particular working cylinder and the at least one associated conduit connection ( 20 . 22 . 24 ) about a longitudinal axis ( 26 ) is rotatable in a cylinder assigned to an angular position, and the spool ( 16 ) for switching the preselected working cylinder and the at least one associated line connection ( 20 . 22 . 24 ) is axially adjustable, characterized in that the control valve ( 16 ) is designed and configured such that in an axial neutral position of the spool ( 16 ) in each angular position, a fluidic connection between the inlet (P) and the return (T) is connected, and that single-acting cylinder and double-acting cylinder by the spool ( 16 ) are operable. Control valve according to claim 1, characterized in that the housing ( 18 ) inside a with the inlet (P) connected annular channel ( 66 ), and the spool ( 16 ) at least one coaxial to the longitudinal axis ( 26 ) arranged through hole ( 62 ), which via a transverse bore ( 58 ) at least in the neutral position of the spool ( 16 ) fluidically with the annular channel ( 66 ) is connectable. Control valve according to claim 1 or 2, characterized in that the spool ( 16 ) radially outwardly fluidly with the pressurized annular channel ( 66 ) connected longitudinal grooves ( 56 ), which by an axial displacement of the spool ( 16 ) with a line connection ( 20 . 22 . 24 ) of a working cylinder are connectable. Control valve according to one of the preceding claims, characterized in that the double-action working cylinder associated line connections ( 20 . 24 ) are arranged in the same angular position in the axial direction adjacent to each other. Control valve according to one of the preceding claims, characterized in that in the housing ( 18 ) a check valve type inlet valve ( 40 ) is provided, which a line connection ( 20 . 22 ) is associated with a single-acting working cylinder, and which via a longitudinal groove ( 56 ) of the spool ( 16 ) with the pressurized annular channel ( 66 ) is connectable. Control valve according to one of the preceding claims, characterized in that the housing ( 18 ) on the bottom side at least one with the line connection ( 20 . 22 ) of a single-acting working cylinder connected, in particular spring-loaded, lowering valve ( 72 ) for pressureless switching of the working cylinder, which by the spool ( 16 ) is operable. Control valve according to claim 6, characterized in that the spool ( 16 ) on the bottom side of a lowering valve ( 72 ) facing end at least one control cam ( 54 ) for cooperation with the lowering valve ( 72 ) having. Control valve according to one of the preceding claims, characterized in that the housing ( 18 ) on the bottom side in the form of a valve plate ( 38 ) is trained. Control valve according to one of the preceding claims, characterized in that the transverse bores ( 58 ) in the spool ( 16 ) radially on the outside with the annular channel ( 66 ) cooperating fine control notches ( 60 ) exhibit. Control device for an agricultural working machine with a control valve according to one of the preceding claims and one with the control valve ( 12 ) associated actuating device ( 14 ). Agricultural work machine with at least one control valve ( 12 ) and / or a control device ( 14 ) according to one of the preceding claims.

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