FI20185181A1 - Power unit for controlling a pressure medium for load control - Google Patents

Abstract

The invention relates to a force unit (10) for controlling a pressure means intended for load control. In connection therewith, a supply circuit (50) is provided for supplying the pressure means pressurized to the power unit (10) and a driving circuit (60), in connection with which the actuator (100) is arranged, to which the pressure means can be supplied for loading said actuator ( 100). The load is achieved by means of control means (12, 14, 15, 16, 16 ') arranged in the power unit (10). A removal circuit (70) is provided adjacent to the power unit (10) for removing the pressure medium from the drive circuit (60). The control means (12, 14, 15, 16) fixed relative to the module body (11) comprise at least: a pressure accumulator (12) to which the pressure medium can be supplied from the supply circuit (50); at least two parallel cylinders (14) to which the pressure medium is supplied from the supply circuit (50), the pressure accumulator (12) and / or the drive circuit (60); directional valves (15, 16, 16 ') arranged adjacent to the cylinders (14) through which the pressure medium supplied from the supply circuit (50) and / or cylinder (14) can be directed to the external drive circuit (60) of the power unit (10) and further to the drive device (100), or through which said directional valves (15, 16, 16 ') the pressure medium returning from the operating circuit (60) can be directed to the cylinders (14) for charging the pressure accumulator (12) and / or to the removing circuit (70); connections for the print medium are formed on a module body (11), whereby the control unit (10) can be arranged integrally between the supply circuit (50) and the drive circuit (60).

Description

Power unit to control the pressure medium for the load no

The present invention relates to a power unit for controlling a pressure medium for load control, which power unit is provided with both a supply circuit for supplying pressure medium under pressure to the power unit and a drive circuit for supplying a pressure medium to the actuator. an outlet circuit is provided in connection with the power unit to remove the pressure medium from the drive circuit.

Power units according to the above are used in particular for controlling working machines, such as forklift cranes, excavator buckets and actuators for moving their arms. The energy requirements of such arrangements, i.e. fuel consumption, in controlling the pressure medium required for load control are relatively high and their placement, especially the placement of power units in connection with actuators, is often challenging. Often, the equipment associated with the operation of the power unit, such as valves and the connections between them for supplying the pressure medium, have to be spaced apart, which in turn disadvantagesfully increases the energy demand and thus the fuel consumption in such power units.

Such hydraulic control devices are disclosed, for example, in EP 1253327, in which one directional valve is provided for each actuator and its control characteristics are not very precise.

A system with more precise control characteristics is disclosed in patent publication F1 125918, which has a system connected directly to the actuator to its several working chambers. Here, the actuator generates the total force acting on the load. Here, however, the structure of the device30 is very limited, at least in order to achieve a precise total force acting on the load.

The object of the present invention is to eliminate or at least substantially reduce the above-mentioned disadvantages, which thus concern the controllability of the power unit and the energy efficiency of the structure.

In order to achieve the above object, the present invention is characterized by what is set forth in the characterizing part of independent claim 1.

The invention achieves the advantage of the previously known arrangements in that the pressure control means and transmission ducts required for load control can be integrated into a very small space in the module body and in such a way that separate ducts or piping causing pressure losses of the control means are not required. In addition, directional valves, cylinders and a pressure accumulator belonging to the control means can be fitted to the module body in the amount required to allow very precise and energy-saving control of the pressure medium between the actuator 15 and the module body in connection with the actuator load. This, therefore, enables a plug-and-play power unit between the supply and operating circuit, which is more energy-efficient and more precisely controlled than in previously known solutions.

Preferred embodiments of the invention are set out in the appended dependent claims.

The invention will now be described in more detail with reference to the accompanying drawings, in which:

20185181 prh 27-02- 2018

Figure 1

Fig. 2 is a schematic view of a power unit according to a preferred embodiment of the invention and the supply and operating circuits arranged in connection therewith, showing an axonometric view of the power unit according to Fig. 1, and

Fig. 3 schematically shows an application of the power unit according to Fig. 2 for controlling the load of a hydraulic cylinder.

20185181 prh 27-02- 2018

Thus, Figure 1 schematically illustrates a power unit according to the present invention, indicated by reference numeral 10. The control means belonging to the power unit are marked inside a box indicated by dashed line 5a, which shows the module body.

In connection with the power unit 10, a supply circuit 50 is provided, by means of which the pressure medium is supplied under pressure to the power unit 10. Preferably the supply circuit 50 comprises a tank 51 from which the pressure medium is pumped by the pump 53 (motor 53a) along the flow path 10 52 to the may also be, for example, air or other fluid pressure medium. The supply circuit 50 may be formed in other ways to supply the pressure medium under pressure to the power unit 10. In other words, the embodiment shown is only one of many preferred examples for supplying the pressure medium.

Figure 2 shows a power unit 10 according to the invention, comprising a module body indicated by reference numeral 11 and control means arranged immovable with respect to the module body 11, which are described in more detail below.

The control means comprise at least one pressure accumulator 12, which is, for example, a piston pressure accumulator. From the supply means 50, a first flow path 20 is arranged in the module body 11 via the connection 12a, which is in direct communication with the pressure accumulator 12 for supplying the pressure medium thereto. The first flow path 20 shown in Figure 1 is also branched by a flow path 20a or flow paths 20a which communicate with cylinders 14 belonging to the control means. There are four cylinders 14 here and are denoted by reference numerals 14a, 14b 14c and 14d. The number of cylinders can generally vary depending on the application. However, there are at least two, preferably 3-5. In Figure 2, they are encapsulated in the ground space of the boundary30 of the protective housing 10a. The flow paths 20a leading to the cylinders lead to their spaces on the piston rod side. Each cylinder is preferably different in size. In this case, the diameters of the piston rod are different, whereby different pressures are obtained from each cylinder via the directional valves 100 shown below for the actuator 100.

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The piston-side spaces of the cylinders 14a, 14b 14c and 14d, in turn, are connected via directional paths 21a, 21b, 21c and 21d to directional valves fixed to the module body 11. The number of directional valves is denoted by reference numerals 15 and 16 and their number may vary depending on the number of cylinders and / or the size of the valves, preferably 9-30. The first directional valves 15, which in the case of four cylinders are sixteen, are here divided into groups of four directional valves, each group of valves being connected to one respective cylinder so that the pressure medium controlled from the respective cylinder can be controlled via each directional valve of the group. Correspondingly, the pressure medium can be directed from the actuator 100 back to the cylinders 14a 14b, 14c and 14d via the first directional valves 15. Thus, at least a portion of the pressurized pressure medium removed from the actuator 100 can be further used to charge the pressure accumulator 12. The transmission of the pressure medium thus takes place via connections (channels) integrated in the power unit.

In addition, the control means include second directional valves, i.e. auxiliary valves 16, through which the pressure medium can be directed from the supply circuit 50 directly through the power unit 10 to the drive circuit 60 and further to the actuator 100. Correspondingly, the directional valves 16 directly through the power unit 10 (12b) to the exhaust circuit 70 connected to the tank 51.

Figure 2 shows a double-acting piston cylinder as the actuator 100. The directional valves 25 and 16 are further preferably divided into two such groups so that the pressure medium can be directed through the supply channels 61 and 62 of the drive circuit 60 to both sides of the piston of the piston cylinder. Such an arrangement can be applied, for example, in the arrangement according to Fig. 3, in which the actuator 100 is applied in turning the arm parts 81 of the bucket arm of the bucket loader or the arm 80 of the crane. Another example of many applications of the power unit according to the invention is, for example, lifting forks of devices for lifting goods, such as forklifts.

The actuator 100 is preferably provided with detection means 110, on the basis of the information detected by which the control means can be controlled by the position required by the actuator 100.

20185181 prh 27-02-2018 to achieve this. Here, the detection means 110 may be, for example, pressure sensors arranged in the pressure spaces of the actuator 100, the observations of which can be transmitted electrically via the communication means lily 112 to the control unit 17, which is part of the power unit control means. Depending on the application, other parameters required for control, such as force, position and / or position, can be detected directly or indirectly by the detection means. Thus, based on the observations, electronic control commands for controlling the control means can be sent from the control unit 17.

Such an arrangement combines a very precise control for loading the actuator with respect to the prior art and a compact design, the novel combination of which achieves considerable energy savings. The control means, which preferably include, for example, the pressure accumulator 12 described above, four cylinders 14a, 14b, 14c and 14d and twenty-four grouped directional valves 15, 16, 16 ', as such achieve very precise load control in the applications shown. It is mentioned, however, that the invention is not limited to these cylinder and directional valve numbers, as previously stated. Combined with this is the fact that the control means which provide precise control are arranged immovably in connection with the module body 11 of the power unit 10. As a result, a large number of flow paths connecting the control means, also in terms of length, are made compact in connection with the power unit to be displaced as one module. This structure significantly shortens the length of the flow paths connecting the control means. This, combined with precise load control, has a direct reducing effect on the energy requirements of the actuator load, such as the fuel consumption of the implement. This also enables a plug-and-play control unit, which is much simpler to install and maintain.

The present invention is not limited to the embodiments shown but can be applied in many ways within the scope of the claims.

Claims (9)

A power unit (10) for controlling a pressure medium for load control, 5 in connection with which a supply circuit (50) for supplying a pressurized medium under pressure to the power unit (10) and a drive circuit (60) are provided in connection with which a pressure medium can be supplied to the actuator (100) for loading a load obtained by means of control means (12, 14, 15, 16, 16 ') arranged in the power unit (10), and 10, in connection with the power unit (10) of which an outlet circuit (70) is provided for removing the pressure medium from the drive circuit (60), characterized in that the power unit (10) comprises a module body (11) comprising control means (12, 14) immobile relative to the module body (11); 15, 16), which include at least: 15 - a pressure accumulator (12) to which the pressure medium can be supplied from the supply circuit (50), - at least two cylinders (14) connected in parallel, to which the pressure medium can be fed from the supply circuit (50), the pressure accumulator (12) and / or the drive circuit (60), 20 - Directional valves (15, 16, 16 ') arranged in connection with the cylinders (14), through which the pressure medium supplied from the supply circuit (50) and / or the cylinder (14) can be controlled to the drive circuit (60) outside the power unit (10) and further to the drive device (100) , or through which said pressure valves (15, 16, ^{16 7} ) the pressure medium returning from the drive circuit (60) can be directed to the cylinders (14) for charging the pressure accumulator (12) and / or 25 to the discharge circuit (70), and that the connections of the pressure accumulator (12), cylinders (14) and directional valves (15) for the pressure medium are formed in the module body (11), whereby the control unit (10) thus formed can be integrated into the supply circuit (50) and the drive circuit. (60) in between. Power unit according to Claim 1, characterized in that the actuator (100) is provided with detection means (110) on the basis of which the control means (12, 14, 15, 16) can be controlled by the position required by the actuator (100). 35 to achieve. 20185181 prh 27-02- 2018 Power unit according to Claim 1 or 2, characterized in that there are 9 to 30 directional valves (15, 16, 16 ') and 3 cylinders (14), respectively. Power unit according to one of the preceding claims 1 to 3, characterized in that there are at least twenty-four directional valves (15, 16, 16 ') which enable at least four cylinders (14a, 14b, 14c, 14d) to be actuated by the actuator (100). to provide the required pressure. Power unit according to Claims 1 to 4, characterized in that each of the cylinders (14; 14a, 14b, 14c, 14d) is connected in each case to four directional valves (15), the state of which can be supplied from at least the respective cylinder to the drive circuit (60). (100) to provide the required pressure or alternatively to the cylinder corresponding to the drive circuit (60) with a pressure accumulator (12) 15 for charging and / or discharging (70). Power unit according to one of the preceding claims 1 to 5, characterized in that the power unit (10) comprises non-return valves (16, 16 ') belonging to the directional valves (15, 16, 16'), through which the pressure medium can be fed directly to the 20 from the operating circuit (50) to the drive circuit (60) and the drive circuit (60) to the output circuit (70). Power unit according to one of the preceding claims 2 to 6, characterized in that the cylinders (14) and the directional control valves (15, 16, 16 ') are electrically controllable, and that their electrical control is obtained from the electrical means 25 on the basis of observed data. Power unit according to one of the preceding claims 2 to 7, characterized in that the detection means (110) are a load-sensing sensor of the actuator (100) and / or a sensor sensing the pressure of the pressure medium in the actuator. Power unit according to one of the preceding claims 1 to 8, characterized in that the actuator (100) is a hydraulic cylinder and in that part of the directional valves (15, 16) is arranged to direct the hydraulic pressure to the piston rod space of the hydraulic cylinder (100) and part of the directional valves (15). , 16) are arranged 35 to direct the pressure medium to the piston-side space of the hydraulic cylinder (100). Power unit according to one of the preceding claims 1 to 7, characterized in that the cylinders (14) have different sizes relative to one another.