FI12788Y1 - Power unit for controlling a pressure medium for load control - Google Patents

Abstract

A power unit (10) for controlling a pressure medium intended for load control, in connection with which power unit (10) a supply circuit (50) is arranged in operation for supplying the pressure medium as pressurized to the power unit (10), a drive circuit (60) , to an operating means (100) arranged in connection with which the pressure medium is feedable for loading said operating means (100), which load is provided by means of control means (12, 14, 15, 16, 16 ') arranged in the power unit (10), and in connection with which power unit (10) a removing circuit (70) is arranged for removing the pressure medium from the drive circuit (60), characterized in that the power unit (10) comprises a modular body (11), comprising an immovable relative to the modular body (11) control means (12, 14, 15, 16), comprising at least: a pressure accumulator (12) to which the pressure medium is feedable from the supply circuit (50), at least two parallel connected cylinders (14) to which the pressure medium is feedable from the supply circuit (50), from the pressure accumulator (12) and / or from the drive circuit (60), directional valves (15, 16, 16 ') arranged in connection with the cylinders (14) through which the pressure medium is supplied from the supply circuit (50) and / or the cylinder ( 14) is controllable to an external drive circuit (60) for the power unit (10) and further to the actuator (100), or through which said directional valves (15, 16, 16 ') the pressure medium returning from the operating circuit (60) can be controlled to the cylinders ( 14) for charging the pressure accumulator (12) and / or to the removing circuit (70), and that the connections of the pressure accumulator (12), the cylinders (14) and the directional valves (15) for the pressure medium are formed on a modular body (11), the the control unit (10) thus formed can be placed in one piece between the supply circuit (50) and the drive circuit (60). In addition, the protection requirements 2-10.

Description

The present invention relates to a power unit for controlling a pressure medium for load control, in connection with which a supply circuit is provided for supplying the pressure medium under pressure to the power unit. by means of control means arranged in the power unit, and in connection with which the power unit is provided - a discharge circuit for removing the pressure medium from the drive circuit. Power units according to the above are used in particular for controlling actuators for moving work machines, such as forklift cranes, excavator buckets and 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 the valves and the connections between them for supplying the pressure medium, have to be spaced apart, which in turn increases - unfavorably the energy demand and thus the fuel consumption in such power units. Such hydraulic control devices are disclosed, for example, in patent publication EP 1253327, in which one directional valve is arranged for each actuator and its control characteristics are not very precise.

N & O A system with more precise control properties is disclosed in patent publication FI © 125918, which has a system I connected directly to the actuator to its several working chambers. Here, the actuator generates the total force acting on the load. However, the structure of the device operating here is very limited in order to achieve at least an accurate total force S acting on the load.

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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-mentioned 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 medium control means and germination 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 pipelines causing pressure losses of the control means are not required. In addition, the directional valves, cylinders and pressure accumulator included in 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 and the module body for actuator loading. Thus, the above enables a plug-and-play power unit between the supply and operating circuit, which is more energy-efficient and more precise in control than in the 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: Fig. 1 shows a diagrammatic view of a power unit according to a preferred embodiment of the invention and the supply and operating circuits arranged in connection therewith, => 30 Fig. 2 shows an axonometric view of the power unit according to Fig. 1, N and

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

Fig. 1 thus 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 10a, 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 a pump 53 (motor 53a) along a flow path 52 to the power unit 10. In the embodiment shown the pressure medium may also be, for example, an 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. Fig. 2 shows a power unit 10 according to the invention, comprising a module body marked with the reference number 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 connection with the pressure accumulator 12 for supplying the pressure medium thereto. From the first flow path 20o 25 shown in Fig. 1, a flow path 20a or flow paths 20a also branch, which is connected to the cylinders 14 belonging to the control means. There are four cylinders 14 here and they are denoted by reference numerals 14a, 14b 14c and 14d. In general, the number of cylinders can vary depending on the application. However, there are at least two, preferably 3 to 5, of them. In Figure 2, they are encapsulated in a> 30 space delimited by the protective housing 10a. The flow paths 20a leading to the cylinders lead to their N spaces on the piston rod side. Each cylinder is preferably different in size. In this case, the diameters of the shaft of the piston S are different, whereby different pressures N are obtained from each cylinder via the directional valves 100 shown below for the actuator 100.

The piston-side spaces of the cylinders 14a, 14b 14c and 14d, in turn, communicate via direct flow paths 21a, 21b, 21c and 21d with directional valves fixed to the module body 11.

The number of directional valves is indicated by reference numerals 15 and 16 and their number may vary depending on the number of cylinders - and / or the size of the valves, being preferably 9 to 30 pieces.

The first directional valves 15, which in the case of four cylinders are sixteen in number, are divided here into groups of four directional valves, each valve group being connected to one respective cylinder so that the pressure medium controlled from the respective cylinder can be directed to each drive circuit 60 and outside the drive unit 10. to the associated actuator 100. Respectively, the pressure medium can be directed back from the actuator 100 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 transfer of the pressure medium thus takes place via connections (channels) integrated in the power unit.

In addition, the control means comprise second directional valves, i.e. auxiliary valves 16, through which the pressure medium can be controlled from the supply circuit 50 directly through the power unit 10 to the drive circuit 60 and further to the actuator 100. Auxiliary valves respectively include directional valves 16 'between the drive circuit 60 the pressure medium to be removed can be directed directly through the power unit 10 (12b) to the discharge circuit 70 connected to the tank 51. Figure 2 shows a double-acting piston cylinder as the actuator 100.

The directional valves 25 are 15 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 has been applied in turning the arm parts 81 of the bucket arm of the bucket loader or the arm 80 of the crane.

Another> 30 - 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.

S 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 to provide the pressure required by the actuator 100. The detection means 110 are a load sensing sensor of the actuator 100 and / or a pressure sensing sensor of the pressure medium prevailing in the actuator. Here, the detection means 110 can be, for example, pressure sensors arranged in the pressure spaces of the actuator 100, the observations of which can be transmitted electrically via data transmission means 111 and 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 can be sent from the control unit 17 to control the control means.

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 in connection with the module body 11 of the stationary 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 movable power unit as a single 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 N also enables a plug-and-play type 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 appended claims.

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Claims (10)

Security requirements A power unit (10) for controlling a pressure medium for load control, the power unit (10) being provided with an in-use supply circuit (50) for supplying a pressurized medium to the power unit (10), a drive circuit (60) having an actuator (100) connected to the actuator (100). is operable to load said actuator (100) provided by control means (12, 14, 15, 16, 16 ") provided in the power unit (10) and arranged in connection with the power unit (10) an outlet circuit (70) 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, 15, 16) arranged to be immobile relative to the module body (11), comprising at least: - 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 supplied from the supply circuit (50), directional valves (15, 16, 16 ") arranged in connection with the cylinders (14), through which - the pressure medium supplied by the supply circuit (50) and / or the cylinder (14) can be controlled by the power unit (12) and / or the drive circuit (60), (10) to the external drive circuit (60) and further to the actuator (100), or through said directional control valves (15, 16, 16 ") the pressure medium returning from the drive circuit (60) is controllable to the cylinders (14) for charging the discharge accumulator (12) and / or the discharge circuit ( 70), and that the connections of the pressure accumulator (12), cylinders (14) and directional valves (15) for the pressure medium O are formed in the module body (11), whereby the power unit (10) thus formed can be placed in one piece in the supply circuit (50) and between the operating circuit (60) ©. I 30> Power unit according to Claim 1, characterized in that the actuator (100) N is provided with detection means (110), on the basis of which information the control means (12, 14, 15, 16) can be controlled during the pressure N required by the actuator (100). to obtain. Power unit according to protection claim 1 or 2, characterized in that there are 9-30 directional valves (15, 16, 16 ”) and 3-5 cylinders (14), respectively. Power unit according to one of the preceding protection claims 1 to 3, characterized in that the directional valves (15, 16, 16 ") have at least twenty-four pieces 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 protection claims 1 to 4, characterized in that each of the cylinders (14; 14a, 14b, 14c, 14d) communicates with a group of four first directional valves (15), the pressure medium of which, depending on the condition of the first directional valves (15) supplyable at least from said cylinder to the drive circuit (60) to provide the pressure required by the actuator (100) or alternatively - from the drive circuit (60) to a corresponding cylinder for charging and / or discharging the pressure accumulator (12). Power unit according to one of the preceding protection claims 1 to 5, characterized in that the power unit (10) comprises auxiliary valves (16, 16 ") belonging to directional valves (15, 16, 16"), through which the pressure medium can be supplied directly from the supply circuit ( 50) to the drive circuit (60) and from the drive circuit (60) to the output circuit (70). Power unit according to one of the preceding protection claims 2 to 6, characterized in that the cylinders (14) and the directional control valves (15, 16, 16 ") are electrically controllable, and - their electrical control is obtained from electronic detection information obtained from the detection means (110). on the basis of. & O Power unit according to one of the preceding protection claims 2 to 7, characterized in that the detection means (110) are a load-sensing sensor I 30 of the actuator (100) and / or a sensor sensing the pressure of the pressure medium in the actuator. a N Power unit according to one of the preceding protection claims 1 to 8, characterized in that the actuator (100) is a hydraulic cylinder and in that part of the directional valves (15, 16) N is arranged to control the hydraulic pressure in the piston rod space of the hydraulic cylinder (100) and part of the directional valves (15, 16) are arranged to direct the pressure medium to the piston-side space of the hydraulic cylinder (100). Power unit according to one of the preceding protection claims 1 to 7, characterized in that the cylinders (14) have different sizes relative to one another. O OF O OF O © O I Jami and Nn N 5 O OF O N 5