HYDRAULIC SYSTEM, SMART POWER UNIT AND OPERATION METHOD OF THE SYSTEM

A hydraulic system with a hydraulic power pack is disclosed having a hydraulic pump, an electric motor arranged to drive the hydraulic pump, and one or more valves connected to the hydraulic pump and arranged to directly manage, by way of direct connections and respective actuators. The hydraulic system also has a hydraulic process computer arranged to control the one or more actuators by way of the valves. An operation method of the system is also disclosed.

TECHNICAL FIELD

The present invention relates, in general, to a hydraulic system which comprises a smart power unit arranged to control the system.

In particular, present invention relates to a Smart Power Unit also named SPU arranged to control the hydraulic system by way of on board electronic circuits.

BACKGROUND ART

Hydraulic systems comprising pump stations are known in many and different fields of technology.

The known hydraulic systems may comprise pump stations having power ranging from 0.15 kW to 7.5 kW and electric control units arranged to control pumps or systems.

In the field of hydraulic systems, for instance, document CN_102566541_A discloses an electric control system or unit of a hydraulic station which includes a power source, a control module and a working module in signal connection with the control module.

According to the known document, the working module includes a heater, an electromagnetic water valve, and an oil pump motor set, wherein the oil pump motor set includes a first oil pump motor, a second oil pump motor and a third oil pump motor.

Moreover, according to the known document, the control module includes a PLC (programmable logic control) unit, a heater failure control unit for protecting the heater, an oil pump failure control unit for protecting the oil pump motor set and an oil level/temperature control unit.

The known electric control system is arranged, in particular, to protect the oil pump motor set as well as to control level and temperature of oil.

According to the known document, the electric control system comprises a very limited number of features and is arranged, in particular, to protect the oil pump motor set by controlling level and temperature of oil.

As a matter of fact, the features of the known electric control system seem strictly linked to pump features and not flexible enough to be integrated in complex and different hydraulic systems.

As a matter of fact, a problem exists if the known electric control system needs to be integrated in hydraulic systems requiring, for instance, further devices.

As a matter of fact the features of the known electric control system are not enough flexible to be easily integrated in and applicable to complex hydraulic systems and, prima facie, strong engineering effort would be required to adapt the known electric control system to complex hydraulic systems in different fields of technology.

Applicant, in general, has noted that known hydraulic systems are not flexible and require electric control units more flexible.

Moreover, Applicant has noted that known electric control units of hydraulic systems do not effectively solve the problem to be very flexible and such to be simply integrated in complex and different hydraulic systems.

DISCLOSURE OF THE INVENTION

The object of the present invention is thus to solve the problems outlined above.

According to present invention, such an object is achieved by means of a hydraulic system and a smart power unit having the features set forth in the claims that follow.

The present invention also relates to an operation method of the system, as claimed.

Claims are an integral part of the teaching of the present invention.

According to a feature of a preferred embodiment the hydraulic system comprises a hydraulic power pack comprising an hydraulic pump and one or more valves arranged to directly manage, by way of direct connections, one or more respective actuators under control of a hydraulic process computer.

According to a further feature the hydraulic process computer of the system comprises a computer board that is programmable and comprises a Safety Architecture arranged to provide a relative level of risk-reduction features.

According to another feature the hydraulic process computer comprises a body including the computer board and a sensor board wherein the sensor board is arranged to shape one side of the body.

BEST MODES FOR CARRYING OUT THE INVENTION

With reference toFIG. 1a hydraulic system10according to present invention comprises a smart power unit or SPU12, one or more actuators141,142, . . . ,14n, (FIG. 1,FIG. 2,FIG. 3), connected or associated to respective sensors411,412, . . . ,41n,and a human machine interface or HMI11.

The hydraulic system10is arranged to be used by an operator in a machine or an electro-mechanic system or device to perform, for instance, motion/control activities. The HMI11is an operator interface, is connected to the SPU12, and is arranged, for instance, to enable or disable functions, set values and/or limits, communicate warnings and/or alarms.

The HMI11comprises, for instance, START/STOP switches, joysticks, potentiometers, or any kind of components arranged to send commands to or receive information from SPU12.

According to further embodiments, the HMI11further comprises a display arranged to display commands or status of commands sent to the SPU12as well as information, warnings or alarms received by the SPU12.

According to the preferred embodiment the HMI11is connected to the SPU12by way of a BUS or a network (BUS)15, for instance a CAN (Controller Area Network) BUS of known type or a wired or wireless network of known type.

The SPU (Smart Power Unit)12, according to the preferred embodiment, comprises a hydraulic process computer or HPC21connected to the HMI11by way of the BUS15, and a hydraulic power pack or HPP61connected, preferably by way of input/output wires16, to the HPC21.

The HPC21preferably comprises a programmable computer board (computer board)23and a sensor board25directly connected to the computer board23.

In particular, the computer board23, according to the preferred embodiment of present invention, is comprised in a body50, for instance a waterproof body, and the sensor board (hydraulic manifold)25is arranged to shape one side of the body50.

The computer board23, according to the preferred embodiment, comprises a Safety Architecture arranged to provide a relative level of risk-reduction features.

For instance the Safety Architecture may comprise a known type SIL (Safety Integrity Level) 2 architecture, in order to provide a relative level of risk-reduction to the operation of the SPU12and of the hydraulic system10.

Preferably, the computer board23comprises, for instance, a first31and a second input array32each associated to a respective first33and second logic processor34in cascade connection to a respective first35and second output36.

The first35and second output36, for instance first and second power outputs, are arranged to directly drive components comprised into the HPP61, as for instance solenoid operated proportional or on-off valves671,672, . . . ,67nwithout the need of external devices.

According to the preferred architecture, the first33and second logic processor34are programmable and are arranged to be customized to the machine or to the electro-mechanic system or device where the hydraulic system10is installed.

Preferably the first33and second logic processor34are communicating each other and are arranged to operate a cross and redundancy check of received information.

For instance the communication between the first33and second logic processor34is made according to the SIL 2 architecture.

According to further embodiments the computer board23is programmable but comprises an architecture with only one input array, one logic processor and one output and is configured for providing, in any case, a certain safety integrity level corresponding to a certain risk-reduction.

The sensor board or hydraulic manifold25, according to the preferred embodiment of present invention, comprises, for instance, one pressure sensor51, one temperature sensor52and a return-line hydraulic flow sensor53or at least one type of the above sensors and is connected to the computer board23by way of input ports of input arrays31,32.

Preferably, the computer board23is laying on the hydraulic manifold25and is arranged to read sensors51,52or53by way of the input ports.

In summary, according to the preferred embodiment of present invention, the sensor board or hydraulic manifold25comprises one or more sensors51,52or53, and is arranged to shape, for instance, a waterproof side of the body50including the computer board23.

The sensor board, in general, is arranged to sense operation parameters of the HPP61and is strongly connected to the computer board23.

The HPP61is comprised of a hydraulic power pack, for instance a mini or micro power pack, and is directly controlled by the HPC21.

According to the preferred embodiment of present invention the HPP61comprises one or more of the following components:an electric motor63sized upon the hydraulic system10necessities, for instance both an AC or a DC type motor, controlled by the HPC21;a hydraulic pump65sized upon the system necessities, and driven by the electric motor63by way of a connection of know type;one or more valves671,672, . . . ,67nselected and applied in order to meet hydraulic system requirements, connected in known way to the pump65, and controlled by the HPC21; Valves671,672, . . . ,67nmay further comprise security valves arranged to meet security requirements of the hydraulic system. One or more of valves671,672, . . . ,67nof the HPP61, preferably, are directly connected to respective actuators141,142, . . . ,14nby way, for instance, of one or two respective pipes and are arranged to directly manage the respective actuators141,142, . . . ,14n.

The actuators141,142, . . . , or14nmay be of linear type (cylinders) or of rotary type (motors), known per se.

Preferably, each sensor411,412, . . . , or41n,is arranged to send feedback information by way of input arrays,31,32, to the HPC21that is configured for performing motion/force control of the actuators141,142, . . . , or14nin closed loop through valves671,672, . . . ,67n.

According to further embodiments the integral sensors411,412, . . . , or41n,are totally or partially missing and/or are distributed in different parts of the machine or of the electro-mechanic system or device.

Operation of the hydraulic system10according to the preferred embodiment disclosed above is the following.

HMI11is mainly arranged to send operative instructions to SPU12by way of the BUS15.

Thanks to such an architecture the HMI11may be located near the operator, for instance in a cabin, and SPU12may be located far from the HMI11and near the electro-mechanic system or device, without requiring very long and complex cables.

Following the operative instructions, the HPC21is arranged to directly send respective commands to the electric motor63and, by way of the valves671,672, . . . ,67n,to the actuators141,142, . . . , or14n.

Thanks to such an architecture the hydraulic system10does not require relays and switches located far from the HPP61for controlling the machine or the electro-mechanic system or device and the HPP61of the SPU12is arranged to directly control actuators141,142, . . . , or14n.

In use, the sensor board25, being preferably integrated in or waterproof connected to the body50, is arranged to directly feedback operation parameters of the pump65or of the HPP61to the computer board23and/or to the HMI11.

Thanks to such high level of integration, for instance pump operation parameters are promptly recognised and managed by the computer board23and/or displayed by the HMI11.

Sensors411,412, . . . , or41n,associated to the actuators141,142, . . . , or14nare arranged to send feedback information in closed loop to the computer board23so that any abnormality may be recognised and managed.

In particular, in case that the computer board comprises at least two logic processors configured according to a safety architecture implementing level 2 risk-reduction features, any abnormality is evaluated and managed by two logic processors in parallel.

In order to better clarify operation of the hydraulic system10, two examples of possible installation of the SPU according to present invention are shown.

A first example relates to a SPU installed in a electrohydraulic twin-scissor lift100for vehicles comprising a master cylinder111and a slave cylinder112.

According to known prior art, a twin-scissor lift is normally developed on a principle of “emitter” and “receiver” slave cylinders.

The emitter cylinder is mechanically connected to a master cylinder located in a platform A which drives the platform out (while lifting) or in (while lowering).

The emitter cylinder pumps oil on the receiver slave cylinder located in platform B which drives the scissor.

Eventual unbalanced load is compensated by a torsion bar.

Therefore, according to known prior art, the conventional twin-scissor lift comprises three cylinders:an emitter cylinder,a receiver cylinder, anda master cylinder.

On the contrary, the SPU12of present invention, applied to a twin-scissor lift100, may replaces the emitter and receiver hydraulic cylinders and the torsion bar by way of a single cylinder (slave cylinder)112of the same size of the master cylinder111.

As a matter of fact, the computer board23, thanks to the fact that it is of programmable type, may be configured to synchronise the position of the slave cylinder112to the position the master cylinder111by conveniently managing signals of a sensor115sending back information from cylinders111and112to the computer board23.

Therefore, the SPU12may be configured to drive only two cylinders.

The slave cylinder112is driven, for instance by a 3/2 proportional valve102comprised into the HPP61.

According to the example the sensor115, for instance, is a rotative potentiometer, arranged to determine the actual scissor height.

Moreover, according to the example, the HPC21of the SPU12is arranged to manage lifting lowering of the master cylinder and parallelism of the slave cylinder through respective proportional valves101,102.

Advantageously, the SPU12allows to reduce manufacturing costs and manpower, simplifies the mechanical solution and reduces hardware materials and spare parts.

A second example relates to a SPU installed, for instance, in a snowplow comprising a cabin71and at least one blade controlled by an electro-mechanic device72.

According to known prior art, a snowplow is normally powered by a conventional hydraulic power pack driven by an electro-mechanic system by way of relays and switches.

Therefore in the vehicle cabin a control panel remotely controls the electro-mechanic device.

The electro-mechanic device, according to prior art, requires at least one wire per each function and other three wires for power. In summary, a fully equipped snowplow can comprise a twenty poles cable for connecting the control panel to the electro-mechanic device; such a cable requires hard work to be driven from inside the cabin to the blade of the snowplow and also requires chassis modification and expansive multiway connectors.

On the contrary, a snowplow designed so as to comprise a SPU12according to present invention, comprises, for instance, the HMI11located into the cabin71.

The HMI11is arranged to manage all the snowplow functions by way of the SPU12located near the electro-mechanic device72and connected to the HMI11through the BUS15, for instance through the CAN-BUS.

Therefore, advantageously, the hydraulic system according to present invention, when applied to a snowplow requires:Minor chassis modification of the snowplow, i.e. less manufacturing costs;Lower connectors cost;Smaller design effort.

In addition, according to further features of the preferred embodiment of present invention, the direct connection of the SPU to actuators of the snowplow, for instance a scraper211, a first and second outrigger212, an orient214and a lift/low215through respective valves201,202,204and205comprised into the HPP61, is such to grant:very high serviceability.

Moreover, the SPU12, by preferably comprising the sensor board25tightly connected to the computer board23, is such to grant when installed in a snowplow:very effective diagnostic features.

Of course, other examples or obvious changes and/or variations to the above disclosure are possible, as regards architecture components and connections as well as details of the described construction and operation method without departing from the scope of the invention as defined by the claims that follow.