Hydraulic apparatus and method of operation

Abstract

A hydraulic apparatus has multiple pump modules, each formed of multiple working chambers having a common high pressure manifold. Connection circuits switchably connect the pump modules to first and second hydraulic circuit portions to allocate capacity as first and second demands for hydraulic fluid vary. In an apparatus that can have two or more connection circuit outputs, controllable valves or deactivating working chamber pumping cycles facilitate re-allocation of pump modules from one output to another, and control strategies address pump module allocation when demands for hydraulic fluid exceed available capacity.

Description

Technical Field

[0001] This invention relates to the field of providing multiple pumped flows of hydraulic fluid to actuator circuits in hydraulic machines, such as vehicles (e.g., excavators) or industrial machines (e.g., injection molding machines, water jet cutting machines). Background Technology

[0002] Currently, it is common practice for the hydraulic actuators of conventional excavators to be driven by two pumps in series (first and second pumps), which are driven by the same prime mover. Typically, there are first and second hydraulic circuit sections, each extending from a hydraulic fluid input to an actuator group (first and second actuator groups). The hydraulic fluid inputs of the first and second hydraulic circuit sections are connected to and receive fluid from the first and second pumps (in a one-to-one correspondence), such that the first and second actuator groups receive pressurized hydraulic fluid from different pumps during normal operation. Each hydraulic fluid circuit section distributes hydraulic fluid to individual actuators within the corresponding actuator group, for example, by using a proportional valve connected in series, which diverts a controllable amount of hydraulic fluid to the actuator. A single actuator with two ports, receiving fluid to actuate in opposite directions (e.g., left and right swing functions), can be connected to different outputs of the same proportional valve. The pressure of the fluid at the input of the hydraulic fluid circuit section can be controlled to be different, for example, due to the different requirements (e.g., flow rate) of the relevant actuators.

[0003] It is well known that in some situations, the flow requirements of the actuators become high enough that it is advantageous to combine the flow rates from two pumps to temporarily drive one or two actuator groups using pressurized fluid from both pumps, and it is well known that one or more controllable valves are provided for this purpose. This can be seen, for example, in US 5940997 (Hitachi), where proportional valves 10 and 8 ('Arm I' and 'Arm II') are switchable to combine flow rates to obtain the peak flow rate of the arm actuator, and proportional valves 7 and 11 ('Hole I' and 'Hole II') are switchable to combine flow rates to obtain the peak flow rate of the boom actuator. Without controllable valves performing the combining function, the pumps would require higher specifications to provide maximum flow rate and pressure, which would result in machine inefficiency.

[0004] We have found that the above-described method is not highly efficient in practice, especially when actuator groups connected to different hydraulic circuit sections have different fluid supply requirements. If, for example, the actuators in the first group require relatively high pressure but relatively low flow rate hydraulic fluid, while the actuators in the second group require relatively low pressure and relatively high flow rate hydraulic fluid, then when the pump output is combined through the valve combination, the pump is required to deliver both relatively high fluid pressure (the highest required pressure) and relatively high flow rate. This results in considerable energy loss due to the requirement to throttle fluid through orifices, such as passages in spool valves, to the hydraulic circuit section requiring lower pressure. We have also found this scenario to be very common, for example, when an excavator is scraping a road and requires the boom to move rapidly at low pressure and the boom to rise slowly at high pressure. Accordingly, existing strategies using combined flow rates with valve combinations can be energy-inefficient, and embodiments of the present invention attempt to provide more efficient and controlled hydraulic fluid flow rates to different hydraulic circuit sections with corresponding actuator groups.

[0005] Some aspects of the present invention address problems related to pump control during the transition from directing hydraulic fluid to one group of actuators to directing hydraulic fluid to another group of actuators. Summary of the Invention

[0006] According to a first aspect of the present invention, an apparatus is provided, comprising:

[0007] First and second hydraulic circuit sections,

[0008] The first hydraulic circuit section has a first hydraulic circuit section input and a plurality of valves configured to regulate the flow rate of hydraulic fluid from the first hydraulic circuit section input to each of a first group of at least two (and typically at least three) hydraulic actuators.

[0009] The second hydraulic circuit section has a second hydraulic circuit section input and a plurality of valves configured to regulate the flow rate of hydraulic fluid from the second hydraulic circuit section input to each of a second group of at least two (and typically at least three) hydraulic actuators.

[0010] prime mover

[0011] A hydraulic machine having a rotatable shaft driven by a prime mover and including at least three working chambers having a volume that cyclically changes with the rotation of the rotatable shaft, each working chamber of the hydraulic machine including a low-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a low-pressure manifold, and a high-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a high-pressure manifold, wherein the working chambers are configured as a plurality of pump modules, each pump module including a group of one or more working chambers and a high-pressure manifold common to each working chamber in the group.

[0012] A hydraulic connection circuit includes multiple connection circuit inputs, each of which is in fluid communication with a high-pressure manifold of a corresponding pump module. A first connection circuit output is in fluid communication with a first hydraulic circuit section input (i.e., a first hydraulic circuit portion), and a second connection circuit output is in fluid communication with a second hydraulic circuit section input (i.e., a second hydraulic circuit portion). The hydraulic connection circuit is configured to connect each of the connection circuit outputs to the hydraulic circuit section inputs and includes multiple valves (e.g., electronically) switchable (typically under the control of a controller) to change the connection circuit output to which the hydraulic circuit section input is connected, such that each pump module is connected to one hydraulic circuit section at a time, and for some or all of the pump modules, the hydraulic circuit section to which the corresponding pump module is connected can be changed.

[0013] A controller configured to actively control at least the low-pressure valves of the working chambers (and in some embodiments, also the high-pressure valves) to determine whether each working chamber experiences an active or inactive cycle, the active cycle having a net displacement of working fluid between the low-pressure and high-pressure manifolds of the working chamber, and the inactive cycle not having a net displacement of working fluid between the low-pressure and high-pressure manifolds of the working chamber, and the valves such that, in response to a first demand for hydraulic fluid in a first hydraulic circuit section, the net displacement of the working chambers of each pump module connected to the first hydraulic circuit section is controlled, and in response to a non-dependent second demand for hydraulic fluid in a second hydraulic circuit section, the net displacement of the working chambers of each pump module connected to the second hydraulic circuit section is controlled.

[0014] In a second aspect, the invention extends to a method of operating a device, the device comprising:

[0015] First and second hydraulic circuit sections,

[0016] The first hydraulic circuit section has a first hydraulic circuit section input and a plurality of valves configured to regulate the flow rate of hydraulic fluid from the first hydraulic circuit section input to each of a first group of at least two (and typically at least three) hydraulic actuators.

[0017] The second hydraulic circuit section has a second hydraulic circuit section input and a plurality of valves configured to regulate the flow rate of hydraulic fluid from the second hydraulic circuit section input to each of a second group of at least two (and typically at least three) hydraulic actuators.

[0018] prime mover

[0019] A hydraulic machine having a rotatable shaft driven by a prime mover and including at least three working chambers having a volume that cyclically changes with the rotation of the rotatable shaft, each working chamber of the hydraulic machine including a low-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a low-pressure manifold, and a high-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a high-pressure manifold, wherein the working chambers are configured as a plurality of pump modules, each pump module including a group of one or more working chambers and a high-pressure manifold common to each working chamber in the group.

[0020] A hydraulic connection circuit includes multiple connection circuit inputs, each of which is in fluid communication with a high-pressure manifold of a corresponding pump module. A first connection circuit output is in fluid communication with a first hydraulic circuit section input (i.e., a first hydraulic circuit portion), and a second connection circuit output is in fluid communication with a second hydraulic circuit section input (i.e., a second hydraulic circuit portion). The hydraulic connection circuit is configured to connect each of the connection circuit outputs to the hydraulic circuit section inputs and includes multiple valves (e.g., electronically) switchable (typically under the control of a controller) to change the connection circuit output to which the hydraulic circuit section input is connected, such that each pump module is connected to one hydraulic circuit section at a time, and for some or all of the pump modules, the hydraulic circuit section to which the corresponding pump module is connected can be changed.

[0021] The method includes:

[0022] Active control (e.g., by a controller) of at least the low-pressure valves of the working chambers (and in some embodiments, also the high-pressure valves) to determine whether each working chamber experiences an active or inactive cycle, the active cycle having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber, and the inactive cycle not having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber, and the valves such that, in response to a first demand for hydraulic fluid in a first hydraulic circuit section, the net displacement of the working chambers of each pump module connected to the first hydraulic circuit section is controlled, and in response to a non-dependent second demand for hydraulic fluid in a second hydraulic circuit section, the net displacement of the working chambers of each pump module connected to the second hydraulic circuit section is controlled.

[0023] And by switching one or more of the valves in the hydraulic connection circuit to change the hydraulic circuit portion to which the pump module is connected.

[0024] The hydraulic connection circuit is used to distribute hydraulic fluid from the pump module to the hydraulic circuit section. "Connection" refers to fluid connection.

[0025] The working chambers that make up each pump module do not need to be adjacent. Typically, each pump module has a high-pressure manifold, which connects (via a high-pressure valve) each working chamber in the group to a high-pressure manifold. Thus, the pump module can realize the displacement of working fluid through its respective high-pressure manifold to the input of the connection circuit and thus to the output of the connection circuit (depending on the setting of the valve in the hydraulic connection circuit) and thereby to the input of the hydraulic circuit section, the displacement being independent of each pump module.

[0026] Typically, the high-pressure manifolds of the pump modules are isolated from each other, at least during normal operation. (The low-pressure manifolds may be common to all working chambers and have no impact on operation). Typically, the working chambers of pump modules connected to different connection loop outputs are controlled based on individual demand signals. Working chambers connected to the first and second connection loop outputs can therefore be controlled to have independent output pressures and flow rates, and one or more pump modules (and therefore their respective working chambers) can be interchanged between being connected to the first connection loop output and being connected to the second connection loop output.

[0027] The first and second demands for hydraulic fluid are signals indicating the demand for hydraulic fluid by the first and second hydraulic circuit sections in order to supply fluid to their respective actuators. The first and second demands (and any third or additional demands) may be a demand for the pressure or flow rate of the hydraulic fluid. It is possible that one or more actuators in the first and second hydraulic circuit sections and / or the first and second actuator groups respectively include sensors, such as pressure or flow sensors, or, in the case of actuators, position, speed, or acceleration sensors. It is possible that the demand is calculated from the output of these sensors. It is possible that the demand is calculated from user-operable controls, such as from a user interface (e.g., a touchscreen controller) or from manually operated controls such as joysticks or handles, such as electrical signals (analog or digital) or hydraulic pressure. The demand may be calculated from proportional valve control signals (which, according to the invention, may optionally be used to control proportional valves included in (or not included in) the respective hydraulic circuit section (this is a conventional control method). The demand may be calculated from signals received via electrical communication networks such as CAN (Controller Area Network), whether from the user or from the electronic controller. The first and second (and any third or additional) requirements are independent of each other, so that the first and second hydraulic circuit sections and the actuators connected thereto can be controlled independently. Typically, the first and / or second requirements are determined by considering the requirements of two or more actuators within a respective actuator group.

[0028] Accordingly, the pressure of the hydraulic fluid at the input of the first hydraulic circuit section and the pressure of the hydraulic fluid at the input of the second hydraulic circuit section can be varied independently. The flow rate of the hydraulic fluid into the first hydraulic circuit section (via the first hydraulic circuit section and to the first actuator group) and the flow rate of the hydraulic fluid into the second hydraulic circuit section (via the second hydraulic circuit section and to the second actuator group) can be varied independently. Furthermore, because changes can be made for each cycle of the working chamber volume, the pressure and flow rate can be changed rapidly. However, individual pump modules can be redistributed from the first to the second hydraulic circuit section and vice versa, thereby enabling the use of more or fewer pump modules as needed.

[0029] The net displacement of the working chamber of the pump module switched to be connected to the hydraulic circuit section is controlled to meet the hydraulic circuit section's demand for hydraulic fluid. The net displacement of the working chamber of the pump module switched to no longer be connected to the corresponding connection circuit output is no longer controlled to meet the hydraulic circuit section's demand for hydraulic fluid. The net displacement of the working chamber of each pump module connected to the corresponding hydraulic circuit section is controlled in a combined manner to meet the hydraulic circuit section's demand for hydraulic fluid.

[0030] Because of these features, the equipment operates efficiently without the power loss that would occur if the outputs of the first and second pump modules were combined with the mixing valve and directly fed to the inputs of both the first and second hydraulic circuit sections.

[0031] Furthermore, the device can be usefully formed by modifying or altering existing hydraulic equipment having first and second hydraulic circuit sections with separate first and second hydraulic circuit section inputs, each of the first and second hydraulic circuit section inputs having multiple hydraulic actuators, and thus the first and second circuit sections and actuators do not need to be modified.

[0032] The first and second hydraulic circuit sections each include at least two (and typically at least three) actuators. Each typically includes one or more (typically multiple) diverter valves that direct an optional portion of the received hydraulic fluid to different actuators within a respective actuator group. The diverter valves are typically proportional valves. Typically, each hydraulic circuit section provides at least two, or typically at least three, independently controllable hydraulic fluid supplies to different actuators.

[0033] It is possible that the first hydraulic circuit portion includes a first valve block portion, and the second hydraulic circuit portion includes a second valve block portion. One or each valve block portion may be part of a metal block where the valve is located. The first and second valve block portions may each include a port that serves as an input to the first or second hydraulic circuit portion, respectively.

[0034] It is possible that the hydraulic connection circuit includes a valve block (e.g., a block including a switching valve) adapted to the hydraulic machine. This enables a convenient connection from the pump module to the hydraulic circuit section.

[0035] It is possible that the valve is a flow divider valve, which can be electronically controlled to dedicatedly connect the high-pressure port of the pump module to either the first connection loop output or the second connection loop output. It is also possible that the valve is a flow divider valve, and the method includes switching the flow divider valve to switch the pump module from being dedicated to the first connection loop output to being dedicated to the second connection loop output, and vice versa. This arrangement can be implemented safely and reliably regardless of the switching of the working chamber between the first and second pump modules. The risk of hydraulic deadheading due to flow obstruction at the valve is largely avoided. It is also possible that each connection loop input (for fluid from the pump module) can be connected to the first or second connection loop output (and thus to the first or second hydraulic circuit section) via corresponding first and second valves (of the hydraulic connection loop), said first and second valves being controlled so that only one or the other is open at a given time. Each connection loop input can be connected to a first or second connection loop output via a single shunt valve, which can operate between a first position and a second position, in which the connection loop input is connected to the first connection loop output and in the second position (either the first or the second) the connection loop input is connected to the second connection loop output.

[0036] The one or more working chambers within each respective pump module are connected together. Each pump module may be a pump module having a common hydraulic fluid output to a hydraulic connection circuit (connection circuit input). The method includes adjusting the net displacement of the working fluid by each pump module. Typically, a controller is operable to adjust the net displacement of the working fluid by each pump module. Typically, hydraulic machines include multiple pump modules, each pump module comprising a respective group of one or more working chambers having a common high-pressure manifold through which they can be connected to a hydraulic connection circuit.

[0037] It is possible that the controller controls at least the low-pressure valve of the working chamber to determine whether each working chamber experiences an active or inactive cycle for each cycle of the working chamber volume, the active cycle having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber, and the inactive cycle not having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber. The method may include controlling at least the low-pressure valve of the working chamber to determine whether each working chamber experiences an active or inactive cycle for each cycle of the working chamber volume, the active cycle having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber, and the inactive cycle not having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber. It is possible that in at least some cases (e.g., when demand remains within at least one value range), the working chambers alternate between active and inactive cycles (typically the controller causes the working chambers to alternate between active and inactive cycles).

[0038] It is possible that the high-pressure manifold of each pump module can be selectively connected (and in use, selectively connected) to the input of only the first hydraulic circuit section or the second hydraulic circuit section. Therefore, only two of the hydraulic circuit sections may exist. However, it is possible that the device includes one or more additional hydraulic circuit sections (the nth hydraulic circuit section, e.g., the third hydraulic circuit section), each additional hydraulic circuit section having a corresponding hydraulic circuit section input (the nth (e.g., the third) hydraulic circuit section input), and one or more additional hydraulic actuators (e.g., a group of one or more additional hydraulic actuators, the nth (e.g., the third) group of one or more hydraulic actuators). One or more (or each) additional hydraulic circuit section may further include one or more valves configured to regulate the flow rate of hydraulic fluid from the corresponding hydraulic circuit section input to each of the corresponding additional one or more (optionally at least two or typically at least three) groups of hydraulic actuators.

[0039] The controller may at least control the low-pressure valve of the working chamber, such that, in response to a corresponding additional (nth, e.g., third) demand for hydraulic fluid, the net displacement of the working chamber of each pump module connected to the corresponding additional (nth, e.g., third) hydraulic circuit section is controlled. The method may include at least controlling the low-pressure valve of the working chamber, such that, in response to a corresponding additional (nth, e.g., third) demand for hydraulic fluid, the net displacement of the working chamber of each pump module connected to the corresponding additional (nth, e.g., third) hydraulic circuit section is controlled. A corresponding additional sensor (nth (e.g., third) sensor) may be present, configured to measure the properties of the hydraulic fluid in the corresponding hydraulic circuit section (nth (e.g., third) hydraulic circuit section) or the properties of one or more of the corresponding actuator groups (nth (e.g., third) actuator groups), said measurement being used to generate the nth (e.g., third) demand. The hydraulic connection circuit may further include, for each additional hydraulic circuit section, another connection circuit output (the nth (e.g., the third) connection circuit output) in fluid communication with the corresponding hydraulic circuit section input (the nth (e.g., the third) hydraulic circuit section input), wherein the plurality of valves of the hydraulic connection circuit may (e.g., electronically) be switched to connect the high-pressure manifold of each corresponding pump module to one or the other of the connection circuit outputs (the first connection circuit output, the second connection circuit output, and one or more additional connection circuit outputs).

[0040] It is possible that the hydraulic connection circuit is configured such that each pump module can be dedicated to one hydraulic circuit section at a time, while one or more pump modules can be connected to the other hydraulic circuit section. Typically, the hydraulic connection circuit is configured such that each pump module can be connected to a first or second hydraulic circuit section and at least one pump module can be connected to the input of each hydraulic circuit section, and typically the hydraulic connection circuit is configured such that at any given time each pump module is dedicated to one of the hydraulic circuit sections to which it can be connected. The controller may at least control the low-pressure valve of the working chamber such that, in response to another (nth, e.g., third) demand for hydraulic fluid, the net displacement of the working chamber of each pump module connected to the other (nth, e.g., third) hydraulic circuit section is controlled. The method may include at least controlling the low-pressure valve of the working chamber such that, in response to another (nth, e.g., third) demand for hydraulic fluid, the net displacement of the working chamber of each pump module connected to the other (nth, e.g., third) hydraulic circuit section is controlled.

[0041] It is possible that the hydraulic connection circuit can be (e.g., electronically) switched to connect some or all of the additional hydraulic circuit inputs to only some of the pump modules in the one or more pump modules. Typically, however, the number of hydraulic circuit sections with non-dependent inputs (the first and second hydraulic circuit sections plus any other hydraulic circuit sections) is smaller than the number of pump modules with individual high-pressure manifolds.

[0042] As mentioned above, the first and second hydraulic circuit sections typically include first and second valve blocks. Each circuit section (typically a valve block) contains at least one proportional valve that can be controlled to divert a proportion of the working fluid received by the hydraulic circuit section to one or more actuators. It is possible, for one or more of the additional hydraulic circuits, that a connecting circuit is operable to directly connect a high-pressure manifold of one or more pump modules to a hydraulic actuator. It is possible, for one or more of the additional hydraulic circuits, that a connecting circuit is operable to connect a high-pressure manifold of one or more pump modules to a hydraulic actuator without an intermediate proportional flow valve. It is possible, that a controller is operable to select a net displacement of the working chamber connected to the hydraulic actuator in response to a demand signal related to the target position, rate of movement, or force of the hydraulic actuator. The method may include selecting a net displacement of the working chamber connected to the hydraulic actuator in response to a demand signal related to the target position, rate of movement, or force of the hydraulic actuator. Therefore, the hydraulic actuator may be directly controlled by a change in the displacement of one or more pump modules, while the connection circuit may be modified to divert the fluid flow from the one or more groups of working chambers to a first or second hydraulic circuit section, typically where a portion of the fluid flow will pass through one or more proportional flow valves.

[0043] It is possible that the first and / or second hydraulic circuit sections further include hydraulic conduits providing a path for hydraulic fluid to flow from the hydraulic circuit section input to at least one actuator of the hydraulic circuit section (typically not all actuators included in the respective hydraulic circuit section) without passing through a proportional valve of the hydraulic circuit section and, selectively (typically under the control of a controller) an electronically controllable bypass valve that allows fluid flow through the hydraulic conduit, such that hydraulic fluid can be selectively supplied to the at least one actuator from the hydraulic circuit section input via one or more proportional valves or via the hydraulic conduit and optionally both. The method may include operating the bypass valve such that fluid received by the input of the first and / or second hydraulic circuit section flows to the at least one actuator of the hydraulic circuit section in a manner other than via the proportional valve of the hydraulic circuit section. Accordingly, the at least one actuator can be selectively driven directly by the received fluid. This is advantageous when the at least one actuator has high flow requirements, as it reduces or avoids energy loss through the proportional valve and / or allows for a higher flow rate of hydraulic fluid to the at least one actuator when needed. An alternative to installing a bypass valve would be to replace the existing proportional valve with a larger capacity proportional valve so that the throttling loss is not significant for the maximum flow capacity. In a standard excavator, the flow to the actuator can be supplied by two proportional valves; however, in the design according to this application, only one proportional valve will supply this actuator. A bypass valve is needed to provide a complete flow without significant throttling loss. The bypass valve can open to allow flow through the hydraulic conduit when the fluid demand of at least one actuator or hydraulic circuit part exceeds a threshold demand, which typically requires more than half of the pump module to meet. When the bypass valve is open, the flow path through at least one proportional valve to at least one actuator can be closed. This can be achieved by directly using the actuator or by adjusting the pressure of the proportional valve's control (e.g., pilot) hydraulic connection to close or move the position of the proportional valve (under the control of the controller). The hydraulic conduit and bypass valve can be separate from the main valve block or can be integrated, in which case the bypass valve will typically have a larger cross-sectional area when open than the proportional valve that would originally regulate the flow of hydraulic fluid to at least one actuator.

[0044] It is possible that the device is configured (e.g., the controller is programmed) such that when the pump module switches from connection to one hydraulic circuit section to another (when the connection circuit input switches from one connection circuit output to another), the working chamber of the corresponding pump module performs (only) inactive cycling during valve switching. The method may include the step of causing the working chamber of the pump module to perform (only) inactive cycling when the valve of the hydraulic connection circuit is switched to connect the pump module to a different hydraulic circuit section. It is possible that when the valve associated with the pump module is switching, the working chamber does not begin any active cycling (e.g., by closing its low-pressure valve). The method may include the step of causing the working chamber of the pump module not to begin any active cycling when the valve of the hydraulic connection circuit is switched to connect the pump module to a different hydraulic circuit section. Typically, in at least some cases, it would otherwise have been performing an active cycling.

[0045] It is possible that the device is configured (e.g., the controller is programmed) such that when the hydraulic circuit section to which the pump module is connected changes, the working chamber of the corresponding pump module undergoes an additional active cycle before the switchable valve is switched, in order to increase the pressure in the high-pressure manifold of the pump module. The method may include causing the working chamber of the pump module to undergo an additional active cycle before the valve in the hydraulic connection circuit is switched to connect the pump module to a different hydraulic circuit section, in order to increase the pressure in the high-pressure manifold of the pump module.

[0046] It is possible that some or all of the pump modules' high-pressure manifolds are connected to a first hydraulic circuit section via a first valve and to a second hydraulic circuit section via a second valve. It is also possible that the controller interleaves the switching of the first and second valves to prevent both from closing simultaneously. The method may include interleaving the switching of the first and second valves to prevent both from closing simultaneously. It is also possible that one of the first and second valves is a normally open valve and the other is a normally closed valve. These features reduce the risk of hydraulic backflow. It is conceivable that when the timing of switching the first and second valves is controlled and / or one or more working chambers are inactive during a change in the hydraulic circuit section to which the pump module is connected, the normally open valve will open faster than it closes, and vice versa for the normally closed valve.

[0047] Possibly, the hydraulic connection circuit includes a conduit extending between first and second connection circuit outputs and having multiple fluid joints along its length, each fluid joint connecting to a different connection circuit input; and multiple blocking valves that can (typically controlled by a controller) selectively block the conduit and thereby determine which connection circuit inputs connect to which connection circuit outputs (and thus which pump modules connect to which hydraulic circuit sections). The method may include controlling the blocking valves to determine which connection circuit inputs connect to which connection circuit outputs. The conduit may extend along a closed loop from a first connection circuit output to a second connection circuit output and back to the first connection circuit output, wherein the joints and blocking valves are distributed around the loop. The conduit may be located within an end plate of the hydraulic machine. The joints may be joints with axial conduits within the hydraulic machine, parallel to the axis of rotation of a rotatable shaft.

[0048] It is possible that the hydraulic connection circuit includes a first manifold portion (which may be a first distribution manifold or a portion thereof) extending to the output of a first connection circuit, a second manifold portion (which may be a second distribution manifold or a portion thereof) extending to the output of a second connection circuit, and a third manifold portion extending to the output of a third connection circuit connected to an input of a third hydraulic circuit portion comprising one or more actuators, and a switching manifold portion, wherein at least the first manifold portion, the second manifold portion, and the switching manifold portion are each selectively connected to one or more of the connection circuit inputs via one or more valves, and wherein the hydraulic connection circuit further includes a manifold diverter valve that can (typically controlled by a controller) be controlled to connect the switching manifold portion to the first manifold portion or the third manifold portion. The method may include switching the manifold diverter valve to switch the switching manifold portion from connection to the first manifold portion to connection to the third manifold portion, and vice versa. Therefore, some pump modules may be connected to the first or second manifold portion via valves, and one or more pump modules may be connected to the first or third manifold portion via valves including diverter valves. In addition, one or more pump modules can be switched from being connected to the output of the first connection circuit or the output of the third connection circuit at one time by operating the manifold diverter valve, and vice versa.

[0049] It is possible that the device is configured (typically the controller is configured, for example, programmed) to connect the pump module equally to the first and second hydraulic circuit sections when the total demand of the first and second hydraulic circuit sections exceeds the maximum capacity of the device. The method may include connecting the pump module equally to the first and second hydraulic circuit sections (by controlling the switching of the hydraulic connection circuit) when the total demand of the first and second hydraulic circuit sections exceeds the maximum capacity of the device. It is also possible that the device is configured (typically the controller is configured, for example, programmed) to connect the pump module to the first and second hydraulic circuit sections when the total demand of the first and second hydraulic circuit sections exceeds the maximum capacity of the device, so that the working chamber can displace fluid to (successfully) meet the demand of a predetermined hydraulic circuit section of the first and second hydraulic circuit sections, but cannot fully meet the demand of the other of the first and second hydraulic circuit sections. The method may include connecting the pump module to the first and second hydraulic circuit sections (by controlling the switching of the hydraulic connection circuit) when the total demand of the first and second hydraulic circuit sections exceeds the maximum capacity of the device, so that the working chamber can displace fluid to (successfully) meet the demand of a predetermined hydraulic circuit section of the first and second hydraulic circuit sections, but cannot fully meet the demand of the other of the first and second hydraulic circuit sections.

[0050] It is possible that the controller is configured (e.g., programmed to) predictively control the valves of the hydraulic connection circuit based on the first and second demands and / or on future values ​​of the first and second demands to change which hydraulic circuit section one or more pump modules are connected to.

[0051] The controller's functionality can be distributed across two or more separate loops and / or hardware processors.

[0052] The method may include operating a valve in a hydraulic connection circuit to connect a pump module equally to the first and second hydraulic circuit sections when the total demand of the first and second hydraulic circuit sections exceeds the maximum capacity of the equipment. The method may also include operating a valve in a hydraulic connection circuit to connect a pump module to the first and second hydraulic circuit sections when the total demand of the first and second hydraulic circuit sections exceeds the maximum capacity of the equipment, so that the working chamber can displace fluid to (successfully) meet the demand of a predetermined hydraulic circuit section in the first and second hydraulic circuit sections, but cannot fully meet the demand of the other of the first and second hydraulic circuit sections.

[0053] The method may include predictively operating valves in a hydraulic connection circuit based on first and second demands and / or future values ​​of the first and second demands to control the valves thereby changing which hydraulic circuit section one or more pump modules are connected to.

[0054] Demand is typically represented by a demand signal calculated by taking into account measurements from the respective sensors. It may also take into account measurements from multiple sensors and / or manually operable controls.

[0055] We refer to the high and low pressures of the manifold as relative pressures. The low-pressure manifold acts as a reservoir for supplying hydraulic fluid to the working chamber, or is connected to said reservoir for pumping and pressurization. The high-pressure manifold acts as a conduit for the hydraulic fluid that has been pressurized by the action of the working chamber.

[0056] Some of the features described above relate to other types of hydraulic devices in which the connection between the pump module and the actuator can be modified, and in a third aspect, the invention more generally relates to a device comprising:

[0057] Multiple hydraulic actuators,

[0058] prime mover

[0059] A hydraulic machine having a rotatable shaft driven by a prime mover and including at least three working chambers having a volume that cyclically changes with the rotation of the rotatable shaft, each working chamber including a low-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a low-pressure manifold, and a high-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a high-pressure manifold, wherein the working chambers are configured as a plurality of pump modules, each of the plurality of pump modules having a corresponding high-pressure manifold common to the pump module.

[0060] A hydraulic connection circuit includes multiple inputs, each in fluid communication with a high-pressure manifold of a corresponding pump module; and multiple connection circuit outputs, each in fluid communication with one or more different hydraulic actuators. The hydraulic connection circuit is configured to connect each of the connection circuit inputs to the connection circuit outputs and includes multiple valves that can (typically electronically) switch (typically under the control of a controller) to change the connection circuit output to which the connection circuit input is connected, such that each pump module is connected to one connection circuit output at a time and thereby connected to one or more of the hydraulic actuators in fluid communication with the corresponding connection circuit output.

[0061] A controller is configured to actively control at least the low-pressure valve of the working chamber (and in some embodiments, also control the high-pressure valve) to determine the net displacement of each working chamber in each cycle of the working chamber volume, such that the net displacement of the working chamber of each pump module connected to the corresponding connection loop output is controlled to meet the corresponding hydraulic fluid demand of the one or more actuators in fluid communication with the corresponding connection loop output.

[0062] The device can be configured (typically the controller is configured, for example, to be programmed) to predictively control the valves of the hydraulic connection circuit based on demand and / or future values ​​of demand, to change which hydraulic connection circuit the pump module is connected to for output and therefore which one or more actuators.

[0063] The invention extends in a fourth aspect to a method of operating a device, the device comprising:

[0064] Multiple hydraulic actuators,

[0065] prime mover

[0066] A hydraulic machine having a rotatable shaft driven by a prime mover and including at least three working chambers having a volume that cyclically changes with the rotation of the rotatable shaft, each working chamber including a low-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a low-pressure manifold, and a high-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a high-pressure manifold, wherein the working chambers are configured as a plurality of pump modules, each of the plurality of pump modules having a corresponding high-pressure manifold common to the pump module.

[0067] A hydraulic connection circuit includes multiple inputs, each in fluid communication with a high-pressure manifold of a corresponding pump module; and multiple connection circuit outputs, each in fluid communication with one or more different hydraulic actuators. The hydraulic connection circuit is configured to connect each of the connection circuit inputs to a connection circuit output and includes multiple valves (typically electronically) switchable to change the connection circuit output to which the connection circuit input is connected, such that each pump module is connected to one connection circuit output at a time and thereby connected to one or more of the hydraulic actuators in fluid communication with the corresponding connection circuit output.

[0068] The method includes actively controlling at least the low-pressure valves of the working chambers (and in some embodiments, also controlling the high-pressure valves) to determine the net displacement of each working chamber within each cycle of the working chamber volume, such that the net displacement of the working chamber of each pump module connected to the corresponding actuator is controlled to meet the corresponding hydraulic fluid requirements of the one or more actuators in fluid communication with the corresponding connection circuit output.

[0069] And by switching one or more valves in the hydraulic connection circuit to change the output of the connection circuit and thereby change the one or more hydraulic actuators to which the pump module is connected.

[0070] Therefore, the net displacement of the working chamber of the pump module switched to the corresponding connection loop output is controlled to meet the hydraulic fluid requirements of the one or more actuators fluidly connected to the corresponding connection loop output. Conversely, the net displacement of the working chamber of the pump module switched off from the corresponding connection loop output is no longer controlled to meet the hydraulic fluid requirements of the one or more actuators fluidly connected to the corresponding connection loop output. If more than one pump module is connected to the corresponding connection loop output, the net displacement of the working chamber of each pump module connected to the corresponding connection loop output is controlled in combination to meet the hydraulic fluid requirements of the one or more actuators fluidly connected to the connection loop output. Fluid communication between the actuator and the connection loop output means a hydraulic connection to the connection loop output, not via a hydraulic connection loop.

[0071] Typically, each pump module can be connected to only one connection loop output at a time (e.g., specifically). It is possible for each connection loop output to be connected to one actuator (e.g., specifically). This allows for precise control of the fluid shifted to each actuator. However, it is possible for each connection loop output to be connected to a group of one or more actuators. Typically, each actuator is connected to one connection loop output (e.g., specifically). Multiple pump modules can be connected to the same connection loop output (e.g., to drive together the one or more actuators fluidly in communication with the connection loop output).

[0072] The working chambers that make up each pump module do not need to be adjacent. Typically, each pump module has a high-pressure manifold, which connects (via a high-pressure valve) each working chamber in the group to a high-pressure manifold. Thus, the pump module can achieve the displacement of working fluid via its respective high-pressure manifold to the connection circuit input and therefore to the connection circuit output (depending on the valve setting in the hydraulic connection circuit) and thereby to the connection circuit output (and to the one or more actuators in fluid communication with said output), the displacement being independent of each pump module.

[0073] Typically, the high-pressure manifolds of the pump module are isolated from each other, at least during normal operation. (The low-pressure manifolds can be common to all working chambers without affecting operation). Typically, the working chambers of the pump module connected to different connection loop outputs are controlled based on individual demand signals. Working chambers connected to different loop outputs can therefore be controlled to have independent output pressures and flow rates, and the pump module can be switched from being connected to one connection loop output to being connected to different connection loop outputs.

[0074] The demand for hydraulic fluid is a signal indicating the demand for hydraulic fluid by one or more actuators fluidly connected to the output of the connection loop. This demand may be, for example, a demand for hydraulic fluid pressure or flow rate, or a demand for actuator position (the demand for fluid flow to be controlled to achieve a specific actuator position). It is possible that the actuator or fluid connection between the connection loop outputs includes sensors, such as pressure or flow sensors, or, in the case of actuators, position, velocity, or acceleration sensors. It is possible that the demand is calculated from the outputs of these sensors. It is possible that the demand is calculated from user-operable controls, such as from a user interface (e.g., a touchscreen controller) or from manually operated controls such as joysticks or handles, using electrical signals (analog or digital) or hydraulic pressure. The demand may be calculated from proportional valve control signals (which, according to the invention, may optionally be used to control proportional valves included in (or excluded from) the corresponding hydraulic circuit portion (this is a conventional control method). The demand may be calculated from signals received via an electrical communication network such as CAN (Controller Area Network), whether from the user or from the electronic controller. The demands are independent of each other, enabling independent control of actuators connected to different connection loop outputs.

[0075] Accordingly, the pressure of the hydraulic fluid at the outputs of different connection loops (and thereby received by different groups of one or more actuators) can vary independently. Typically, the flow rate of the hydraulic fluid through the different connection loop outputs can also vary independently. Furthermore, because variations can be implemented for each cycle of the working chamber volume, pressure and flow rate can change rapidly for individual groups of one or more actuators (connected to different connection loop outputs). However, individual pump modules can be redistributed among the connection loop outputs (and therefore the actuators), allowing for the use of more or fewer pump modules as needed (for a particular one or more actuators).

[0076] The net displacement of the working chamber of a pump module switched to be connected to the connection loop output is controlled to meet the hydraulic fluid requirements of one or more actuators in fluid communication with the connection loop output. The net displacement of the working chamber of a pump module switched to no longer be connected to the connection loop output is no longer controlled to meet the hydraulic fluid requirements of one or more actuators in fluid communication with the connection loop output. The net displacement of the working chamber of each pump module connected to the respective connection loop output is controlled in a combined manner to meet the hydraulic fluid requirements of one or more actuators in hydraulic communication with the connection loop output.

[0077] It is possible that the valve is a flow divider valve, which can be electronically controlled to dedicatedly connect the high-pressure port of the pump module to either a first connection circuit output or a second connection circuit output. However, it is also possible that the hydraulic connection circuit includes multiple valves (e.g., a matrix of valves), thereby allowing each connection circuit input and therefore each pump module to connect to any of a plurality of (or in some embodiments, each) connection circuit outputs. The method may include operating one or more of the valves to switch the pump module from connection to a first connection circuit output to connection to a second connection circuit output.

[0078] It is possible that the plurality of switches includes two switches that connect the connection loop input in parallel to the connection loop output. The method may include operating (and the controller may be configured to operate) the two switches such that only one or the other is disconnected at a given time. The method may include ensuring (and the controller may be configured to ensure) that each connection loop input (and therefore each pump module) is always connected to at least one connection loop output.

[0079] It is possible that some or all of the pump modules' high-pressure manifolds are connected to the first connection circuit output via a first valve and to the second connection circuit output via a second valve. It is possible that the controller interleaves the switching of the first and second valves to prevent both from closing simultaneously. The method may include interleaving the switching of the first and second valves. It is possible that one of the first and second valves is a normally open valve and the other is a normally closed valve. These features reduce the risk of hydraulic backflow. It is possible that the controller considers that when controlling the timing of switching the first and second valves and / or causing one or more working chambers to perform an inactive cycle causing the pump module to disconnect from the first connection circuit output (and thus the first actuator or group of one or more actuators) and connect to the second connection circuit output (and thus the second actuator connected to the group of one or more actuators), the normally open valve will open faster than it will close, and vice versa for the normally closed valve.

[0080] As with the first and second aspects, the one or more working chambers within each respective pump module are connected together. Each pump module may be a pump module having a common hydraulic fluid output to a hydraulic connection circuit (connection circuit input). The method includes adjusting the net displacement of the working fluid by each pump module. Typically, a controller is operable to adjust the net displacement of the working fluid by each pump module. Typically, hydraulic machines include multiple pump modules, each pump module comprising a respective group of one or more working chambers having a common high-pressure manifold through which they can be connected to a hydraulic connection circuit.

[0081] It is possible that the controller controls at least the low-pressure valve of the working chamber to determine whether each working chamber experiences an active or inactive cycle for each cycle of the working chamber volume, the active cycle having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber, and the inactive cycle not having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber. The method may include controlling at least the low-pressure valve of the working chamber to determine whether each working chamber experiences an active or inactive cycle for each cycle of the working chamber volume, the active cycle having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber, and the inactive cycle not having a net displacement of the working fluid between the low-pressure and high-pressure manifolds of the working chamber. It is possible that in at least some cases (e.g., when demand remains within at least one value range), the working chambers alternate between active and inactive cycles (typically the controller causes the working chambers to alternate between active and inactive cycles).

[0082] It is possible that, during operation, the hydraulic connection circuit directly connects one or more pump modules to the one or more hydraulic actuators in fluid communication with the hydraulic circuit output, typically without intermediate proportional flow valves. It is possible that at least one (and in some embodiments, each) connection circuit output is connected to a single actuator. The controller may be operable to select a net displacement of the working chamber connected to the hydraulic circuit output (and thus the single actuator) in response to a demand signal related to the target position, rate of movement, or force of the actuator. The method may include selecting a net displacement of the working chamber connected to the hydraulic actuator in response to a demand signal related to the target position, rate of movement, or force of the hydraulic actuator. Therefore, the hydraulic actuator may be directly controlled by changes in the displacement of one or more pump modules.

[0083] It is possible that the device is configured (e.g., the controller is programmed) such that when the pump module is switched from being connected to a connection loop output (and thus to one or more actuators in communication with the connection loop output), the working chamber of the corresponding pump module performs an inactive cycle during valve switching. It is possible that when switching the hydraulic connection loop valve associated with the pump module, the working chamber does not begin any active cycle (e.g., by closing its low-pressure valve). Typically, in at least some cases, it would have already performed an active cycle.

[0084] It is possible that the device is configured (e.g., the controller is programmed) such that when the pump module switches from being connected to one connection loop output to being connected to another connection loop output, the working chamber of the corresponding pump module undergoes an additional active cycle before the switching valve to increase the pressure in the high-pressure manifold of the pump module. It is also possible that, before the pump module switches from being connected to one actuator to being connected to another actuator, the working chamber of the corresponding pump module undergoes an additional active cycle before the switching valve to increase the pressure in the high-pressure manifold of the pump module.

[0085] It is possible that the device is configured (e.g., the controller is programmed) such that when the pump module switches from connection to one hydraulic circuit section to another (when the connection circuit input switches from one connection circuit output to another), the working chamber of the corresponding pump module performs a (only) inactive cycle during the valve switching (of the hydraulic connection circuit). The method may include the step of causing the working chamber of the pump module to perform a (only) inactive cycle when the valve of the hydraulic connection circuit is switched to connect the pump module to a different hydraulic circuit section. It is possible that when switching the connection circuit valve associated with the pump module, the working chamber does not begin any active cycle (e.g., by closing its low-pressure valve). The method may include the step of causing the working chamber of the pump module not to begin any active cycle when the valve of the hydraulic connection circuit is switched to connect the pump module to a different hydraulic circuit section. Typically, in at least some cases, it would have already performed an active cycle.

[0086] It is possible that the device is configured (e.g., the controller is programmed) such that when the hydraulic circuit section to which the pump module is connected changes, the working chamber of the corresponding pump module undergoes an additional active cycle before switching the connection circuit valve in order to increase the pressure in the high-pressure manifold of the pump module. The method may include causing the working chamber of the pump module to undergo an additional active cycle before the valve of the hydraulic connection circuit is switched to connect the pump module to a different hydraulic circuit section in order to increase the pressure in the high-pressure manifold of the pump module.

[0087] It is possible that some or all of the pump modules' high-pressure manifolds are connected to a first hydraulic circuit portion via a first valve (of the hydraulic connection circuit) and to a second hydraulic circuit portion via a second valve (of the hydraulic connection circuit). It is possible that the controller interleaves the switching of the first and second valves to prevent both from closing simultaneously. The method may include interleaving the switching of the first and second valves to prevent both from closing simultaneously. It is possible that one of the first and second valves is a normally open valve and the other is a normally closed valve. These features reduce the risk of hydraulic backflow. It is conceivable that when the timing of switching the first and second valves is controlled and / or one or more working chambers are inactive during a change in the hydraulic circuit portion to which the pump module is connected, the normally open valve will open faster than it closes, and vice versa for the normally closed valve.

[0088] It is possible for the controller to be configured (e.g., programmed to) predictive control (of a hydraulic connection circuit) valves that depend on demand and / or future values ​​of demand to change which connection circuit output one or more pump modules are connected to. The method may include predictive control (of a hydraulic connection circuit) valves that depend on demand and / or future values ​​of demand to change which connection circuit output one or more pump modules are connected to.

[0089] The controller's functionality can be distributed across two or more separate loops and / or hardware processors.

[0090] The hydraulic connection circuit may include a directional control valve for each actuator (i.e., a valve that controls the direction of movement of the actuator, such as a valve that diverts fluid to one side or the other side of a dual piston cylinder).

[0091] In the apparatus of the first and third aspects of the invention, and in the method of the second and fourth aspects of the invention, problems may arise when the total demand for the working fluid of two or more hydraulic circuit sections (the sum of a first demand and a non-dependent second demand (in some embodiments) plus one or more additional demands for the hydraulic fluid of another hydraulic circuit section) is a high fraction of or exceeds the maximum net displacement of the working chamber of the pump module simultaneously connected to the two or more hydraulic circuit sections via a hydraulic connection circuit. When this occurs, it is possible that all demands for hydraulic fluid cannot be met simultaneously, and the net displacement of the working chamber of the pump module connected to the first of the two or more hydraulic circuit sections cannot be fully met. However, when one or more pump modules are later switched to be connected to the first of the two or more hydraulic circuit sections due to a change in demand, the net displacement of the first of the two or more hydraulic circuit sections suddenly increases due to the additional capacity, which may cause jitter and difficulties in the control process of the apparatus.

[0092] Therefore, it is possible to adjust the demand signal to prevent a sudden increase (e.g., an increase exceeding a threshold) in the displacement of the working fluid to the hydraulic circuit section (in the case of the first or second aspect of the invention) and / or the output of the connecting circuit (in the case of the third or fourth aspect of the invention) in response to changes in the output of the hydraulic circuit section and / or the connecting circuit to which the pump module is connected. Typically, the demand signal associated with the output of the hydraulic circuit section and / or the connecting circuit to which the pump module is connected is an adjusted demand signal.

[0093] The demand may be, for example, proportional to the flow rate of hydraulic fluid required per unit time or per cycle of the working chamber volume or per revolution of the rotatable shaft (in the first or second case to the corresponding hydraulic circuit section, or in the third or fourth case to the one or more actuators connected to the output of the corresponding connection circuit). It may be an analog or digital signal.

[0094] It is possible that when multiple demands for hydraulic fluid associated with a corresponding hydraulic circuit section (in the case of the first or second aspect) or one or more actuators in fluid communication with a corresponding connecting circuit output (in the case of the third or fourth aspect) make it impossible to satisfy the multiple demands simultaneously, some or all of the multiple demands are reduced (typically proportionally) by multiplying by a scaling factor, regardless of which pump module is connected to which hydraulic circuit section or connecting circuit output. The scaling factor may (e.g., calculated) make them (the multiple demands) total at most the maximum displacement rate that can be simultaneously achieved by all but one of the pump modules that can be connected to the individual hydraulic circuit or connecting circuit output. Typically, the scaling factor is, or at most, the ratio of (a) the maximum displacement rate that can be simultaneously achieved by all but one of the pump modules that can be connected to the individual hydraulic circuit or connecting circuit output to (b) the sum of the multiple demands (for the hydraulic fluid associated with each of the (as needed) individual hydraulic circuit or connecting circuit outputs).

[0095] This will generally apply when the sum of the multiple demands exceeds (a) the maximum displacement rate that can be achieved simultaneously by all but one of the pump modules that can be connected to the output of an individual hydraulic circuit or connecting circuit (and not just when it exceeds (c) the maximum displacement rate that can be achieved simultaneously by all the pump modules that can be connected to the output of an individual hydraulic circuit or connecting circuit).

[0096] It is possible that all pump modules have the same capacity and can all be connected to the same hydraulic or connection circuit output. In this case, the ratio (a) / (c) is the ratio of (the number of pump modules minus one) to (the number of pump modules).

[0097] In some embodiments, the demand consists of a first demand for hydraulic fluid from the one or more actuators that are in fluid communication with the first hydraulic circuit portion or the output of the first connection circuit, and a second demand for hydraulic fluid from the one or more actuators that are in fluid communication with the second hydraulic circuit portion or the output of the second connection circuit.

[0098] In this case, it is possible, at least when the sum of the first and second demands exceeds the maximum displacement of the pump module that can be connected to the first or second hydraulic circuit section or is in fluid communication with the output of the first connection circuit, to reduce the first and / or second demands by multiplying by a scaling factor, which is at most (a) the ratio of the maximum displacement rate that may be simultaneously achieved by all but one of the pump modules that can be connected to the output of the first or second hydraulic circuit or connection circuit to (b) the sum of the first and second demands.

[0099] This may apply when the sum of the multiple requirements exceeds (a) the maximum displacement rate that can be simultaneously achieved by all but one of the pump modules that can be connected to the output of the first or second hydraulic circuit or connection circuit.

[0100] The use of these scaling ratios has the following effect: connecting another pump module to the hydraulic circuit section or connecting circuit output (as needed) will not cause a sudden jump in the output shift of the hydraulic circuit section or connecting circuit output. It is possible to connect an additional pump module to the hydraulic circuit section or connecting circuit output (as needed) when the scaled demand reaches the maximum output of the pump module currently connected to the hydraulic circuit section or connecting circuit output. Therefore, it is possible to reduce the demand by multiplying by the scaling factor so that the reduced demand never exceeds the maximum output of the pump module currently connected to the hydraulic circuit section or connecting circuit output (as needed).

[0101] More generally, there may be n hydraulic circuit sections, each with associated requirements (in the case of the first or second aspect of the invention), thus a total of n requirements. There may be n connection circuit outputs, each with associated requirements (in the case of the third or other aspect of the invention), thus a total of n requirements. In some embodiments, n = 2. However, it is possible that n is greater than 2.

[0102] There may be n demands for hydraulic fluid to a corresponding hydraulic circuit section (in the case of the first or second aspect of the invention) or to an actuator connected to a corresponding connection circuit output (in the case of the third or fourth aspect of the invention), and when the n demands make it impossible to satisfy all n demands simultaneously regardless of which pump module is connected to which connection circuit output, if one of the n demands is for a maximum displacement of more than (100 / n)% for a pump module that can be connected to the corresponding hydraulic circuit section or connection circuit output, then the corresponding hydraulic circuit section or connection circuit output has a pump module connected thereto capable of delivering at least (100 / n)% of the maximum displacement.

[0103] It is possible that if a first demand among n demands is for more than (100 / n)% of the maximum shift, but another second demand among n demands is for less than (100 / n)% of the maximum shift, such that fewer pump modules than are required to deliver (100 / n)% of the maximum shift can be used to satisfy the second demand, then one or more pump modules used to satisfy the second demand do not need to be connected to the hydraulic circuit section or connecting circuit output associated with the first demand but not with the second demand, such that the hydraulic circuit section or connecting circuit output associated with the first demand has a pump module connected thereto capable of delivering a maximum shift greater than (100 / n)% (and the shift delivered to the hydraulic circuit section or connecting circuit output associated with the first demand is greater than (100 / n)% of the maximum shift).

[0104] It is possible that if one of the demands is less than (100 / n)% but more than a threshold for the maximum displacement of a pump module, then each hydraulic circuit section or connecting circuit section has a pump module connected thereto capable of delivering (100 / n)% of the maximum displacement, optionally wherein if one of the demands is less than the threshold, the demand is scaled down such that it totals at most the maximum displacement rate that can be achieved by all but one of the pump modules that can be connected to any of the outputs of the hydraulic circuit section or connecting circuit.

[0105] Optionally, n = 2. Therefore, there may be first and second demands (for hydraulic fluid to the first and second hydraulic circuit sections or the one or more actuators connected to the first and second connecting circuit sections), and when the first and second demands make it impossible to simultaneously satisfy both demands regardless of which pump module is connected to the first hydraulic circuit section or connecting circuit section and which pump module is connected to the second hydraulic circuit section or connecting circuit section, the respective hydraulic circuit section output by the connecting circuit has a pump module connected thereto capable of delivering 50% of the maximum displacement. Furthermore, it is possible that if one of the demands is less than 50% but above a threshold for the maximum displacement of the pump module, each hydraulic circuit section or connecting circuit section has a pump module connected thereto capable of delivering 50% of the maximum displacement, optionally wherein if one of the demands is below the threshold, the demands are scaled down such that they total at most the maximum displacement rate that can be achieved by all but one of the pump modules that can be connected to the first or second hydraulic circuit section or connecting circuit output.

[0106] It is possible that the method includes, or the controller is configured to control the hydraulic connection circuit so as to: connect pump modules to hydraulic circuit sections (in the case of the first or second aspect) or connection circuit outputs such that the number or capacity of pump modules connected to each hydraulic circuit section or connection circuit output is proportional to the hydraulic fluid demand of the hydraulic circuit section (in the case of the first or second aspect) or the one or more actuators connected to the connection circuit output (in the case of the third or fourth aspect), typically rounded to the nearest integer.

[0107] Other methods could be considered to adjust the demand signal to avoid sudden increases in shift, such as applying the maximum slewing rate to each demand signal.

[0108] The features described above are optional features of each of the four aspects of the present invention. Attached Figure Description

[0109] Examples of embodiments of the present invention will now be described with reference to the following figures, in which;

[0110] Figure 1 This is a schematic diagram of a hydraulic device according to the present invention;

[0111] Figure 2 Corresponding to Figure 1 It has some additional details;

[0112] Figure 3 This is a partially exploded view of the pump module and end plate;

[0113] Figure 4 This is a schematic diagram of the pump module;

[0114] Figure 5 This is a schematic diagram of the controller;

[0115] Figure 6A , 6B 6C is a prior art machine (6A) with no pumped flow merging under low load; a prior art machine (6B) with conventional pumped flow merging under high load; and a graph of flow demand (x-axis) versus pressure (y-axis) for two hydraulic circuit sections of the machine (without merging) according to the invention (6C) under high load.

[0116] Figure 7 This is a schematic diagram of a hydraulic device with three hydraulic circuits.

[0117] Figure 8 This is a schematic diagram showing the overall portion of the distribution block where the diversion valves are arranged;

[0118] Figure 9 This is a flowchart of the operating procedure for redistributing the pump module to the hydraulic circuit section;

[0119] Figure 10 The flow demand signal and maximum flow capacity of each of the two hydraulic circuit sections are shown, as well as the change of the diverter valve control signal and position over time during the process of redistributing the pump module from hydraulic circuit section 2 to hydraulic circuit section 1.

[0120] Figure 11 This is a schematic diagram of the alternative diversion valve arrangement;

[0121] Figure 12 This is a schematic diagram of the alternative diversion valve arrangement;

[0122] Figure 13 This is a schematic diagram of the alternative diversion valve arrangement;

[0123] Figure 14 This is a schematic diagram of the alternative connection loop arrangement;

[0124] Figure 15 A and 15B are schematic diagrams of alternative connection loop arrangements;

[0125] Figure 16 This is a schematic diagram of another alternative connection loop arrangement;

[0126] Figure 17 This is a schematic diagram of the pressure reducing valve arrangement;

[0127] Figure 18A It is a curve (on the y-axis) showing the maximum flow rate (dashed line) across the output of the connecting loop and the actual flow rate (solid line) for a given demand flow rate (dashed line) as the demand flow rate increases linearly with time (x-axis), without limitation on the demand signal for individual outputs; the numbers represent the number of pump modules connected to the hydraulic circuit section / connecting loop output;

[0128] Figure 18B Corresponding to Figure 18A At the same time, it limits the demand signals for individual outputs;

[0129] Figure 19 This is a schematic diagram showing the flow rate satisfied by the output of the first and second hydraulic circuit sections / connecting circuits in the first method;

[0130] Figure 20A , 20B 20C is a schematic diagram of the required flow rates for the first and second outputs in the second method, where the x-axis represents the demand in units of the capacity of individual pump modules, and where both the first and second demands exceed 50% of the maximum shift. Figure 20A The second demand is reduced to just below 50% of the maximum shift. Figure 20B ), and the second demand further decreased ( Figure 20C ), with no demand restrictions, and Figure 20D ,20E And 20F corresponds to Figure 20A , 20B And 20C, but demand is limited. Detailed Implementation

[0131] refer to Figure 1 The excavator 1 (an example of a hydraulic system) includes an engine 2 that drives multiple pump modules 4A, 4B, 4C, 4D, 4E, 4F, 4G, and 4H (multiple pump modules), each of which includes several working chambers driven by a prime mover via a common rotating shaft 6 in the form of a piston-cylinder unit (PCU). The working chambers within a given pump module are connected to provide a common hydraulic fluid output to a distribution block 10 via corresponding high-pressure manifolds 8A, 8B, 8C, 8D, 8E, 8F, 8G, and 8H. The distribution block has an input (connection loop input) for receiving fluid from each high-pressure manifold, and outputs 12 and 14 (connection loop outputs) connected to or acting as inlets to or serving as inlets to the first and second hydraulic circuit sections 20 and 22. Pressure sensors 17 and 19 measure the pressure at the inlets to the first and second hydraulic circuit sections. The first hydraulic circuit section has a first valve block 24 and a first plurality of actuators (6, 28, 30), in this example, a boom 26, a bucket 28, and a right rail 30. A boom bypass valve 32 is configured to provide an alternative path for hydraulic fluid to flow directly from the inlet to the first hydraulic circuit section to the boom instead of via the first valve block. The second hydraulic circuit section has a second valve block 26 and a second plurality of actuators (34, 36, 38), in this example, a ladle 34, a slewing function 36, and a left rail 38. A ladle bypass valve 40 is configured to provide an alternative path for hydraulic fluid to flow directly from the inlet to the second hydraulic circuit section to the ladle instead of via the second valve block. The first and second hydraulic circuit sections return fluid output to the tank 42. A controller 50 controls valves regulating fluid flow in each working chamber and valves within the distribution block as described herein.

[0132] Figure 2 The features in the middle correspond to Figure 1 The characteristics, and Figure 2Within the distribution block, for each pump module, there are first and second diversion valves 52 and 54, which can be controlled to connect the high-pressure manifold (output, when pumping) of the pump module to a first or second distribution manifold 56 and 58. The first or second distribution manifold extends through the distribution block to corresponding outputs 12 and 14 and inputs 16 and 18 of the first and second valve blocks (connecting loop outputs). Additionally, a pressure reducing valve 55 connects each high-pressure manifold to a slot. The controller receives demand signals from sensors via input 49, pressure (and other feedback signals) via input 47, and transmits the signals via signal lines 89 and 93 to the working chamber valve and via control line 51 to the switchable valve of the distribution block. Features specific to this invention are shown within dashed box 53, and the remaining features are known from existing hydraulic equipment such as excavators.

[0133] Figure 8 More details of a single integral part of the distribution block are shown below. In this example, the first and second diverter valves for each pump module are lift valves, controlled in series such that one is open while the other is closed, and both switch between open and closed simultaneously, and vice versa (or have a short delay to ensure one is always open to reduce the risk of hydraulic backflow). Therefore, it acts as a diverter valve. In some embodiments, the first and second valves are formed with a single valve component that moves together under the control of a single valve control signal. In other embodiments, they are separate but controlled in series. For each pair of first and second valves, one is typically a normally open valve and the other is typically a normally closed valve, which also reduces the risk of hydraulic backflow, especially in the event of a loss of control signal. Figure 8 As shown in the diagram, valve 52 is normally open while valve 54 is normally closed. However, they can be either normally open or normally closed simultaneously.

[0134] Check valves 55 and 57 are provided, which open away from the switchable valve to prevent flow from the hydraulic circuit section to which they are connected back into the high-pressure manifold. This maintains isolation between the high-pressure manifolds and prevents fluid from draining from the higher-pressure manifold into the lower-pressure manifold. In embodiments where one or more pump modules also function as motors to receive hydraulic fluid returned from the actuators of the hydraulic circuit section, the check valves may be omitted (at least for pump modules that function as motors). In this case, using Figure 11 Alternatively, a configuration of 13 would be useful. It is also possible to replace the check valve with a single blocking valve operated by a pair of solenoids or a pilot-operated check valve, or to include a selectively openable bypass around the check valve.

[0135] Pressure reducing valve 59 provides an outlet to the discharge line 61 connected to the tank for use in cases of excessive pressure (e.g., during a backfeed event).

[0136] The controller is also connected to the pump module and transmits control signals to regulate the displacement of the pump module. As we will describe, this is achieved by sending active control signals to an electronic control valve that regulates the flow of fluid into and out of the working chamber of the pump module.

[0137] Accordingly, the controller can switch which pump modules are connected to which inputs of the hydraulic circuit section, and can adjust the net displacement of each individual pump module, as we will describe further below.

[0138] Pump modules typically contain multiple working chambers, for example, n working chambers in a 360° / n phase configuration, where n is an integer, such as 2, 3, or 4. Phase separation enables relatively smooth fluid output to the respective high-pressure manifolds. The distribution of working chambers to pump modules is generally fixed, but is defined by the connection of the output of each working chamber in the pump module to the same high-pressure manifold via conduits. Typically, each working chamber in the same pump module is fixedly connected to the same shared high-pressure manifold. The working chambers forming individual pump modules do not need to be separated from the working chambers forming other pump modules; for example, working chambers from different pump modules can be staggered along the shaft, which may be advantageous, for example, for distributing torque along the shaft.

[0139] The number of working chambers in each pump module does not need to be the same. One method for connecting the working chambers to form a pump module is... Figure 3 Shown in Figure 3 A connection is formed in the pump end plate 66 to fit into the pump housing 68, which has multiple working chambers. Figure 3 This is a partially exploded view, with the dashed line indicating the centerline of the manifold. The manifold of the pump endplate mates with the pump housing. Conduits having manifolds 70A, 70B, 70C, and 70D extend through the pump housing and are internally connected to the high-pressure outlet of each of a plurality of working chambers. Each working chamber is connected to one conduit. In one example, a first pump module is formed in a group 72 of three adjacent bores 74 in the pump housing, and these working chambers are connected to conduit 70A. The conduit extends from the group of bores through the housing along its axis and intersects a face of the machine housing, where the conduit port directly mates with a mating port on the endplate. Within the endplate, individual conduit manifolds 70A, 70B, 70C, and 70D are internally connected to the first, second, and third pump module fluid manifolds 76A, 76B, and 76C. Each conduit port is connected to a pump module fluid port, but a pump module fluid port may be connected to one or more conduit ports. The pump module fluid manifold connects to the individual input manifolds of the distribution block and thus acts as the high-pressure manifolds 8A, 8B, and 8C for the individual pump modules. Therefore, the pump module is defined from the respective pump module. In this example, each conduit connects to the output of three working chambers, and therefore each pump module has a multiple of three working chambers.

[0140] Figure 4 This is a schematic diagram of a portion of an electronically commutated hydraulic machine (ECM) implementing pump module 4A. The ECM includes multiple working chambers, each having a cylinder 80 with a working volume 81 defined by the inner surface of the cylinder, and a piston 82 driven by an eccentric cam 84 from a rotatable shaft 83 and reciprocating within the cylinder to cyclically change the working volume of the cylinder. The rotatable shaft is rigidly connected to and rotates with a drive shaft. A shaft position and / or speed sensor 85 determines the instantaneous angular position and / or rotational speed of the shaft and transmits this via signal line 86 to a controller 50, thereby enabling the machine controller to determine the instantaneous phase of the cycle for each cylinder.

[0141] Each working chamber is associated with a low-pressure valve (LPV) in the form of an electronically actuated face-sealed lift valve 87. The LPV has an associated working chamber and is operable to selectively seal a passage extending from the working chamber to a low-pressure hydraulic fluid manifold 88, which connects one or more, or virtually all, of the working chambers of the pump module shown herein to the low-pressure hydraulic fluid manifold and slot 42 of the device. The LPV is a normally open solenoid-actuated valve that passively opens to fluid communication between the working chamber and the low-pressure hydraulic fluid manifold when the pressure in the working chamber is less than or equal to the pressure in the low-pressure hydraulic fluid manifold (i.e., during the intake stroke), but can be selectively closed under the active control of the controller via the LPV control line 89 to prevent fluid communication between the working chamber and the low-pressure hydraulic fluid manifold. The valve may also be a normally closed valve.

[0142] Each working chamber is further associated with a corresponding high-pressure valve (HPV) 90, each in the form of a pressure-actuated delivery valve. The HPV opens outward from its respective working chamber and is operable to seal a corresponding passage extending from the working chamber to a high-pressure hydraulic fluid manifold 91, which can deliver fluid as... Figure 2 The diagram shows one or more, or virtually all, working chambers connected to a high-pressure hydraulic fluid manifold 8A of the pump module. The HPV acts as a normally closed pressure-opening check valve, passively opening due to the pressure difference across the valve and taking into account the force of the biased components within the HPV. The HPV also acts as a normally closed solenoid-actuated check valve, which the controller can selectively maintain open via HPV control line 93 once the HPV opens due to pressure in the associated working chamber. Typically, the HPV cannot be opened by the controller against pressure in the high-pressure hydraulic fluid manifold. The HPV can also be opened under the control of the controller, or partially opened, when pressure is present in the high-pressure hydraulic fluid manifold but there is no pressure in the working chamber.

[0143] In pumping mode, the controller selects the net displacement rate of hydraulic fluid from the working chamber to the high-pressure hydraulic fluid manifold via the hydraulic pump by actively closing one or more of the LPVs (Limited Ports) near the maximum volume point in the associated working chamber circulation, closing the path to the low-pressure hydraulic fluid manifold, and thereby guiding the hydraulic fluid away via the associated HPV (but not actively keeping the HPV open) during subsequent contraction strokes. The controller selects the number and sequence of LPV closures and HPV openings to generate flow or create shaft torque or power to satisfy the selected net displacement rate. The controller's above "selection" is refreshed periodically or continuously. The selection is refreshed or updated when the pump module is assigned to or deassigned from a specific portion of the hydraulic circuit.

[0144] Some embodiments may include a pump module that is also electrically rotatable, thereby regenerating energy from hydraulic fluid received from the hydraulic circuit portion and converting energy into mechanical energy, for example, when the actuator is lowered or when the rotary motor operates as a pump to apply braking torque. In these cases, the working chamber of the pump module is also adapted to the motor, in which case the controller actively controls the HPV and LPV and can implement an electrically rotatable operating mode, wherein the controller selects the net displacement rate of the hydraulic fluid displaced by the hydraulic machine via a high-pressure hydraulic fluid manifold, and actively closes one or more of the LPVs shortly before the minimum volume point in the circulation of the associated working chamber, closing the path to the low-pressure hydraulic fluid manifold that causes the hydraulic fluid in the working chamber to contract by the remainder of the contraction stroke. The associated HPV opens when the pressure is equalized across it and guides a small amount of hydraulic fluid out via the associated HPV kept open by the hydraulic machine controller. The controller then actively keeps the associated HPV open, typically until approaching the maximum volume in the circulation of the associated working chamber, thereby allowing hydraulic fluid to flow from the high-pressure hydraulic fluid manifold to the working chamber and applying torque to the rotatable shaft.

[0145] In addition to determining whether to close or keep the LPV open in each cycle, the controller can operate to change the precise phase of HPV closure relative to the changing working chamber volume, thereby selecting the net displacement rate of the hydraulic fluid from high pressure to low pressure hydraulic fluid manifold (and vice versa).

[0146] The arrows on manifolds 86 and 92 indicate the hydraulic fluid flow in electric rotary mode; in pumping mode, the flow reverses. Pressure reducing valve 94 protects the hydraulic machine from damage.

[0147] In practice, there are examples such as Figure 4The diagram shows several pump modules connected by a common shaft, and a single controller that transmits control signals to valves associated with each working chamber of each pump module. The working chambers within the pump modules are not necessarily evenly spaced around the shaft, but are typically staggered to distribute the load along the shaft.

[0148] Although the working chambers of each pump module are fixed, the pump modules supplying flow to the hydraulic circuit section can be dynamically changed using flow dividers. For example, at one time, there may be four pump modules connected to the first hydraulic circuit section and four pump modules connected to the second hydraulic circuit section. At another time, there may be six pump modules connected to the first hydraulic circuit section and two pump modules connected to the second hydraulic circuit section.

[0149] Figure 5 This is a schematic diagram of controller 50. The controller includes processor circuitry 100, which electronically communicates with memory 102, which stores a database 104 of pump modules and which working chambers are fixedly associated with which pump modules, and a database 106 of which pump modules are currently connected to which hydraulic circuit section. The controller receives demand signals 108 indicating the demand for working fluid in each of the first and second hydraulic circuit sections, as well as shaft position and / or speed signals, via signal line 86. Demand signals 108 may be simple pressure signals; however, as an alternative embodiment, demand signals may be in the form of electronic joystick position signals, while additional pressure signals are provided to the controller as input. Outputs from the controller include working chamber valve control lines 89, 93 (for controlling the LPV and, if necessary, the HPV), and valve switching control lines 110 for actuating the diverter valves 52, 54 within the distribution block.

[0150] The demand signal can be relatively simple, such as a measurement of pressure at the hydraulic input of the corresponding hydraulic circuit; or more complex, such as a signal indicating both pressure and flow requirements for the corresponding hydraulic circuit. The controller can receive signals indicative of individual actuators or operator demands from the equipment via manual controls. This method achieves compatibility with pre-existing hydraulic equipment.

[0151] During operation, the controller maintains a database of which pump modules are connected to which hydraulic circuit section, starting from the default configuration. The controller also maintains an accumulator (an internal variable stored in the controller) 112 that represents the difference between the required volume of hydraulic fluid and the volume of hydraulic fluid delivered to each hydraulic circuit section by the pump modules connected to the corresponding hydraulic sections. As the rotatable shaft rotates, a decision point is reached for each working chamber at different times (shaft position). At the decision point for a given working chamber, the controller determines which hydraulic circuit module the working chamber is connected to (this requires querying a database 104 of pump modules and which working chambers are fixedly associated with which pump modules, and a database 106 of which pump modules are currently connected to which hydraulic circuit section), and the controller then updates the accumulator for the hydraulic circuit section to which the working chamber is connected based on the received demand of said circuit section. The controller then compares the accumulator value to a threshold, and if the accumulated demand exceeds the threshold, its scheduling then transmits a valve control signal causing the working chamber to perform an activity cycle in which the working chamber achieves a net displacement of the working fluid, and subtracts the net displacement of the working fluid from the value stored in the accumulator. Otherwise, it causes the working chamber to perform an inactive cycle in which no net displacement of the working fluid is achieved (e.g., the controller can signal the LPV of the working chamber to keep the LPV open throughout the entire cycle of the working chamber volume), and does not modify the accumulator. In this way, the controller makes a decision about whether to perform an active cycle for each working chamber based on the demand from the hydraulic circuit portion to which the working chamber is connected. The accumulator and demand signal can use any convenient unit. In a known example, the demand is expressed as a "displacement fraction," which is the maximum possible displacement of one revolution of the rotating shaft, referred to as F. d In volumetric terms, the target flow velocity is F. d The product of the rotational speed of the rotatable shaft.

[0152] Occasionally, the controller will determine that there is a requirement to reallocate a pump module from one hydraulic circuit module to another to meet a change in hydraulic fluid demand. In this case, the controller will transmit control signals to the relevant valves in the allocation module to switch the high-pressure manifold of the pump module from one hydraulic circuit module to another (in embodiments with two hydraulic circuit modules, the other hydraulic circuit module) and update the database 106 which pump modules are currently connected to which hydraulic circuit modules. Therefore, in the future, when a decision point is reached for each working chamber of a pump module that has been switched from one hydraulic circuit module to another, the controller reads the value of the shift accumulator of the new hydraulic circuit module and thus the hydraulic fluid demand of the new hydraulic circuit module.

[0153] The timing of selection as the redistribution pump module is important, and the torque can be selected with respect to the timing of circulation in one or more working chambers to minimize pulsations / ripples occurring from those respective chambers. Forecasts of the flow originating from the connected working chambers can be used during this distribution process to (specifically) select the time to perform redistribution. Redistribution can be performed to increase the flow supply at a future time, or simply to increase flow capacity.

[0154] It is noteworthy that the controller can simultaneously deliver hydraulic fluid with very different pressures and flow rates to each hydraulic circuit section. In a simple example, the pressure at the input of the hydraulic circuit section is measured, and the accumulator of each hydraulic circuit section increases over time proportionally to the error between the measured pressure and the setpoint pressure. This error can also be integrated over time and added to the accumulator. The pressure setpoint can be different for each hydraulic circuit section and can change rapidly in response to the load on the actuator or the position of the proportional valve. For example, in response to a significant increase in the pressure setpoint, each assigned working chamber can perform an active cycle until a corrected pressure setpoint is obtained. Furthermore, if the actuator increases its positive absorption flow, many working chambers will need to undergo active cycles to maintain the pressure setpoint. Additionally, the hydraulic circuit sections can receive very different volumes of hydraulic fluid because the net displacement of the working fluid by the pump module connected to each hydraulic circuit section is completely independent, even though the working chambers connected to each hydraulic circuit section are driven by the same engine via the same shaft.

[0155] Although the controller is shown here as being implemented by a single processor, those skilled in the art will understand that the functionality of the controller can be easily distributed among multiple processors and / or circuits.

[0156] Available from Figures 6A to 6C See the benefits of this invention. Figure 6A The diagram illustrates the operation of a conventional hydraulic machine, such as an excavator, with tandem pumps that drive first and second hydraulic circuit sections via corresponding actuator groups. A control valve block allows selective combination of flows from the tandem pumps when the flow is not combined and is at a relatively low demand level. The x-axis represents the flow rate and is numbered according to the number of pump modules used to deliver the desired flow rate. That is, the desired flow rate on the x-axis between 3 and 4 will require no fewer than 4 pump modules (even for a required rate only slightly higher than 3). In this case, it is assumed that each pump module has the same number of working chambers n, each with the same capacity, and therefore m pump modules deliver the maximum flow output of m × n working chambers. Q max1 The maximum flow rate delivered using a single pump (equivalent to a 4-pump module) in the working chamber, and Q max2 This represents the maximum flow rate delivered by the working chamber, which can utilize two pumps (equivalent to eight pump modules). The y-axis represents pressure. Section 112 shows the output pressure P1 and flow rate Q.demand1 The power output (pressure x flow rate) of the first hydraulic circuit section. Section 114 shows the output pressure P2 below P1 and above Q. demand1 flow rate Q demand2 The power output of the second hydraulic section. A similar total power output is provided to the hydraulic circuit section, but with very different pressure and flow characteristics.

[0157] refer to Figure 6B In a conventional excavator circuit, when a hydraulic circuit section requires a hydraulic fluid flow rate (Q) that can be satisfied by a single pump... max1 At higher hydraulic fluid flow rates, the control valve block combination draws flow from both pumps to meet the flow requirements, but this means the power output is determined by the product of the higher pressure requirement P1 and the total flow requirement. Therefore, instead of the power requirement being equal to the product of the required pressure and the flow requirement of the first hydraulic circuit section 112, and the required pressure and the flow requirement of the second hydraulic circuit section 114, power is wasted, as represented by section 116. In practice, this is dissipated by throttling the fluid flow. This demonstrates that conventional excavator layouts are inefficient when one hydraulic circuit section requires high pressure and low flow while other hydraulic circuit sections require low pressure and high flow.

[0158] Figure 6C The effects achievable using this invention are demonstrated. In this example, the second hydraulic circuit section has a flow requirement that requires 6 out of 8 available pump modules at a relatively low pressure P2, while the first hydraulic circuit section has a flow requirement that can be met by a single pump module out of 8 available pump modules even at a relatively high pressure P1. The controller switches 6 of the pump modules to the second hydraulic circuit section, assigning only 1 pump module to the first hydraulic circuit section, and thus the appropriate flow requirement 112 can be delivered to the first hydraulic circuit section and the appropriate flow requirement 114 can be delivered to the second hydraulic circuit section without any energy waste represented by section 116. Accordingly, the present invention has provided a method for efficiently meeting the requirements of the first and second hydraulic circuit sections.

[0159] The controller uses demand signals from various hydraulic circuit sections to determine the net displacement of the working fluid in the working chamber of the pump module connected to the corresponding hydraulic circuit section and also to determine when to switch the pump module from one hydraulic circuit section to another. Demand signals can be used for feedback control of the displacement. For example, demand signals may include or determine measurements of pressure in the hydraulic circuit section (at some or all of the inputs to the hydraulic circuit section, at the conduit extending to the actuator, or at the output of the hydraulic circuit section, such as a throttle (orifice) across the output of the hydraulic circuit section), and signals from manual controls, such as joystick position signals. Demand signals can be used for feedforward control. For example, demand signals may be determined from a user interface (e.g., manually operable controls, such as joystick position), or from demands calculated by the controller (e.g., in response to current or predetermined activity of the equipment), or from demands derived from spool valve commands (e.g., pilot valve pressure) and / or the position of proportional valves within the hydraulic circuit section.

[0160] In largely redesigned applications, actuators assigned to the first and second hydraulic circuit sections can be selected as needed. For example, the first section may have a swing motor, a scoop primary actuator, a boom secondary actuator, and a travel side, while the second section may have a scoop secondary, a boom primary, a bucket, and another travel side.

[0161] In the conventional application of this invention, which involves modifying existing equipment, the actuator has been assigned to the hydraulic circuit section.

[0162] Figure 7This is a schematic diagram of an alternative system architecture in which a third hydraulic circuit section 120 is present. The third hydraulic circuit section includes a hydraulic rotary actuator 122 (which, for example, controls the rotation of the vehicle body in an excavator). Another distribution block 124 communicates with high-pressure manifolds 8C, 8D, 8E, and 8F of four (i.e., only some) pump modules, and for the main distribution block 10, it contains valves controllable by a controller to switch the pump modules to the corresponding hydraulic circuit section input 126 (the input to the third hydraulic circuit section). This third input is connected to the rotary actuator via a rotary directional valve block 128, which regulates fluid flow so that the device rotates clockwise or counterclockwise as needed. A switchable valve in the other distribution block is controlled by the controller in conjunction with a switchable valve in the main distribution block 10, such that pump modules 4C, 4D, 4E, and 4F, which can be connected to the third hydraulic circuit section, are connected to only one of the three hydraulic circuit sections at any given time. Therefore, the outputs of pump modules 4A, 4B, 4G, and 4H can be redirected to the first or second hydraulic circuit section, and the outputs of pump modules 4C, 4D, 4E, and 4F can be redirected to the first, second, or third hydraulic circuit section. The controller receives a demand signal for the third hydraulic circuit section and maintains an accumulator for the third hydraulic circuit section to adjust the displacement of the working fluid to meet the demand. Another distribution block can be integrated with the main distribution block.

[0163] like Figure 1 and 2 As shown, within the hydraulic circuit section, bypass valves (typically spool valves) 32 and 40 can be provided to selectively and directly supply hydraulic fluid to specific actuators (the boom in the case of boom bypass valve 32, and the scoop in the case of scoop bypass valve 40), bypassing the proportional valve in the main valve control block. This is advantageous because for actuators that consume particularly high volumetric flow rates of hydraulic fluid (e.g., boom or scoop functions), the proportional valve may cause excessive energy loss through throttling, or even prevent sufficient hydraulic fluid from being supplied to these functions. This is particularly useful when adapting the invention to existing excavator equipment (whereby the main spool valve would throttle too much power and the pressure drop would be too high). Existing excavator equipment supplies some actuators via the main spool valve and the secondary spool valve. To retrofit the invention (e.g., for an excavator), the secondary spool valve of the actuator will be shut off. (If the invention were designed during manufacturing rather than retrofitting, it would not require a bypass spool valve and could have only a single high-capacity spool valve.)

[0164] exist Figure 7In this embodiment, the slewing loop can therefore be directly connected to one or more pump modules without any proportional valves (as is common in conventional excavators). Furthermore, the pump modules connected to the slewing actuator can be precisely controlled based solely on demand signals regarding the slewing function. This arrangement is energy efficient (because it omits proportional valves and reduces or eliminates throttling) and allows for fine-tuning control of actuator movement (because the working chambers of the respective pump modules, which are in direct fluid communication with the slewing actuator, operate in shift control mode).

[0165] Those skilled in the art will understand that the third hydraulic circuit section and any other additional hydraulic circuit sections can be connected to any subset or even all of the pump modules. However, this may be meaningless given the maximum flow requirements required to distribute all pump modules to a particular actuator.

[0166] exist Figure 1 and 2 In one embodiment, there are 256 possible combinations of connections from the pump module to the first and second hydraulic circuit sections (254 of which provide at least some flow to both hydraulic circuit sections), but if all the pump modules have the same capacity, there are actually nine different options regarding how many pump modules are allocated to each hydraulic circuit section.

[0167] In some embodiments, one or more pump modules are fixedly connected to one of the circuit sections, and the corresponding fluid flow does not pass through a distribution valve. The working chamber of the fixed distribution pump module is always controlled together with the working chambers of any other pump modules currently connected to the same circuit section to meet the hydraulic fluid demand of said circuit section.

[0168] In one example, the eight pump modules can be connected as follows:

[0169] Pump Module 1: Loop Section 1 Only

[0170] Pump Module 2: Loop Section 1 Only

[0171] Pump Module 3: Loop Section 2 Only

[0172] Pump Module 4: Loop Section 2 Only

[0173] Pump module 5: Loop section 1 or 2

[0174] Pump module 6: Loop section 1 or 2

[0175] Pump module 7: Loop section 2 or 3 (for example, it can be an oscillating or rotary loop).

[0176] Pump module 8: Loop section 2 or 3 (for example, it can be an oscillating or rotary loop).

[0177] In this configuration, loop section 1 can receive the output of up to 5 pump modules; loop section 2 can also receive the output of up to 5 pump modules, and loop section 3 can receive the output of up to 2 pump modules. Including several pump modules that are fixedly connected / distributed to a specific hydraulic loop section can reduce complexity and cost, but it also reduces flexibility.

[0178] Figure 9 This is a flowchart of the operating procedure implemented by the controller to switch the pump module from one hydraulic circuit section to another. During this process, the controller monitors the required flow rate of the first hydraulic circuit section 150A and the second hydraulic circuit section 150B. The controller then periodically calculates the number of working chambers / PCUs required by 152A and 152B to supply the required fluid flow to the first and second hydraulic circuit sections. Next, referring to databases 104 and 106, the controller determines whether the working chambers, which are part of the pump modules currently connected to each hydraulic circuit section, are sufficient to provide the required flow rate and whether they should be redistributed. If there is no requirement to change the allocation, the procedure continues from the beginning. Otherwise, the controller determines that 154 should redistribute one or more pump modules, determines which one or more pump modules should be redistributed, and then updates database 106 with information on which pump modules are assigned to which hydraulic circuit sections, and sends valve control signals 158 to the diverter valves 52 and 54 to implement the change. Further details regarding this switching procedure are described below. When a decision point is reached in the future regarding whether to cause an individual working chamber to undergo an active cycle, the controller will automatically consider the demand and demand accumulator of the hydraulic circuit connected to the relevant working chamber when determining whether the corresponding working chamber should undergo an active or inactive cycle of its volume.

[0179] The controller also takes into account the limitations on torque, flow, or power output for individual pump modules, and these vary dynamically as the pump module is redistributed from one hydraulic circuit section to another.

[0180] When the total fluid demand of all hydraulic circuit sections is within the total capacity of the hydraulic machine, pump modules can be allocated to hydraulic circuit sections such that the total number of working chambers allocated to each hydraulic circuit section shifts the supply demand, rounding up as needed. However, if the total fluid demand of each hydraulic circuit section exceeds the total capacity of the hydraulic machine, or if the number of working chambers in each pump module is insufficient to meet the total demand, the controller employs an alternative strategy.

[0181] In one strategy, when an overload criterion is met, the controller allocates a pump module with working chambers equal to half the total capacity available for the first hydraulic circuit section and half the total capacity available for the second hydraulic circuit section. Alternatively, one hydraulic circuit section may be prioritized and allocated sufficient working chambers to meet demand, while another hydraulic circuit section is allocated the remaining working chambers, which may be displaced and insufficient to meet demand. For example, it may be determined that a hydraulic circuit section including the steering actuator will be prioritized. Given immediate demand, where possible, a pump module may be returned to the default allocation state of the hydraulic circuit section by the controller.

[0182] For example, each hydraulic circuit section can be assigned a working chamber equal to a proportion of its current, time-averaged, or predicted displacement demand, as a fraction of the total current, time-averaged, or predicted displacement demand, without rounding as needed.

[0183] When it is determined that a pump module will be redistributed from one hydraulic circuit section to another, one or more of the following pump modules may be considered for redistribution:

[0184] -Preference for a specific pump module or a specific number of pump modules to be used for round trips, or

[0185] - For the preference or requirement of excluding one or more pump modules from supplying fluid to one or more hydraulic circuit sections, or

[0186] For example, requirements include ensuring a smooth hydraulic fluid flow / reducing flow ripple (and therefore considering which pump module will provide the smoothest flow during transitions, if connected to a particular hydraulic circuit module), minimizing the number of flow divider switching events (minimizing losses), and distributing the flow rate (and therefore losses) among different pump modules and switchable valves. These can be basic requirements.

[0187] In some embodiments, a pump module is reallocated when the flow or displacement demand (of a hydraulic circuit section) exceeds a threshold. This is particularly useful when there are three or more hydraulic circuit sections. For example, when a demand signal indicates a target flow rate (“flow domain” control), the allocation of another pump module to the hydraulic circuit section can be triggered, Q. demand >Q n-1 (where Q) demand For traffic demand, and Q n The maximum flow rate is associated with the number ('n') of pump modules allocated to the corresponding hydraulic circuit section. This control method attempts to retain excessive potential shift. For example, if the flow demand Q demand If the flow rate is 65 liters per minute (LPM) and n = 2 (where one of the pump modules has a maximum flow rate of 60 LPM), then Q n-1The value is 60, and the condition of the equation is satisfied, therefore the number n should increase. In this example, pump modules will be allocated, thereby increasing the total capacity of pump modules allocated to the corresponding hydraulic circuit sections, and the condition of the equation will be false (65 < 120). The allocation and the value of n will remain constant until the triggering condition is true again. Those skilled in the art will see that the equation can be easily modified to be more conservative (e.g., Q). demand >Q n-1.5 or not too conservative (Q) demand >Q n-0.5 The latter carries the risk that the required displacement of the hydraulic circuit portion may exceed the displacement achievable from the pump module connected to the corresponding connection circuit output during the process.

[0188] Alternatively, instead of providing triggers within the flow domain, it may be possible to signal demand based on a displacement fraction (Fd, the fraction of the maximum possible displacement per revolution of a rotatable shaft). As the demand displacement fraction for a given hydraulic circuit section approaches the maximum available displacement fraction, another pump module should be assigned to the corresponding hydraulic circuit section. The threshold demand that triggers the assignment of an additional pump module can be a predetermined fraction of the maximum displacement associated with the pump module currently assigned to the corresponding hydraulic circuit section. For example, for a threshold of 0.9, when the displacement demand changes from below 0.9 of the maximum displacement of the working chamber of the pump module connected to the hydraulic circuit section to above 0.9, an additional pump module will be assigned and added to the group. This will trigger a change in the Fd of the working chamber in the corresponding pump module group, as the total available displacement of the hydraulic circuit section has changed.

[0189] A group of pump modules can exist, serving as a 'pool' from which modules are selected for allocation. Pump modules that require surplus are therefore not selected / deallocated.

[0190] The physical state of the switchable valve (in a hydraulic connection circuit) could mean that the pump module is connected to the hydraulic circuit section, and if the corresponding working chamber is operating in idle mode, there is no pressurized fluid being delivered to or from the high-pressure tunnel and the corresponding working chamber. Therefore, the controller might consider this pump module to be "de-assigned" and thus not contributing to meeting the needs of the hydraulic circuit section to which it is connected. In the same physical valve switching state, the pump module could also be considered to be "assigned" (regardless of the mode of the corresponding working chamber).

[0191] The redistribution of pump modules from one hydraulic circuit section to another can be determined based on current demand (e.g., flow demand) or an estimate or forecast of demand. The controller can predict future increases or decreases in demand; for example, it can detect standard or recurring demand cycles (e.g., common movement sequences of its actuators when an excavator performs common tasks such as digging, lifting, rotating, and then dropping objects). The controller can measure specific gradients in the demand. In response, the controller can redistribute one or more pump modules from one hydraulic circuit section to another before the demand occurs, based on predicted future demand. The controller can consider the typical slope or gradient of the demand signal. The controller can also consider data from sensors (e.g., accelerometers, vibration sensors, tilt sensors), for example, detecting whether the device is at a certain gradient, or is moving, or is not moving.

[0192] In any case, a hysteresis can be provided so that an unnecessary shift (assignment or deassignment) between the number of pump modules connected to a hydraulic circuit section is not triggered. An example of an unnecessary shift might be caused by temporary / dynamic oscillations in shift demand around a (flow or shift) threshold level, where such oscillations do not follow a longer-term trend or steady state. This hysteresis can result from a common trigger level requiring the assignment of an additional pump module being higher than the common trigger level allowing the removal of a pump module to be connected to another hydraulic circuit section.

[0193] When the pumping module switches from one hydraulic circuit section to another, the controller may need to correct the data regarding the active cycle allocation and accumulated demand of the working chamber. In the example given above, the accumulator is used to store the accumulated unmet demand of the hydraulic circuit section in absolute units (e.g., volumetric flow rate units), increasing proportionally to the demand and decreasing the volume of fluid displaced from the working chamber as an active cycle is performed.

[0194] Figure 10 This illustrates the controlled switching process when a pump module is redistributed from one hydraulic circuit section to another (hydraulic circuit section 2 to hydraulic circuit section 1). Demand signals 201 and 202 for hydraulic circuit sections 1 and 2 are expressed based on flow rate and vary over time. In this example, each hydraulic circuit section initially has the same number of pump modules assigned to it, each pump module having the same number of working chambers, each of which has the same capacity, so the maximum flow rates 211 and 212 delivered to hydraulic circuit sections 1 and 2 are initially the same. The middle and lower traces respectively show the valve control signals 220 and 230 and valve positions 222 and 243 (open or closed) of the normally open and normally closed valves 52 and 54 of an individual pump module (e.g., pump module 4A) initially connected to one of the hydraulic circuit sections (e.g., section 2).

[0195] At time 'A', the demand signal for another hydraulic circuit segment (segment 1) exceeds a threshold, and the controller makes a decision to reallocate one or more pump modules from hydraulic circuit segment 2 to hydraulic circuit segment 1 to increase the maximum possible flow to hydraulic circuit segment 1. In some embodiments, a drop in demand below a threshold may trigger the de-allocation of a pump module from a hydraulic circuit segment, causing it to be reallocated to another hydraulic circuit segment, for example, to distribute capacity evenly among the hydraulic circuit segments. The determination of how many pump modules should be reallocated to hydraulic circuit 1 may take into account whether hydraulic circuit 2 will continue to be able to meet its demand without one or more pump modules (taking into account the demand threshold); the application of priority differentiation logic, for example, prioritizing the flow capacity of the hydraulic circuit segment feeding the steering actuator.

[0196] Once the controller has determined at time A that one or more pump modules should be redistributed from hydraulic circuit section 2 to section 1, at time B, the controller sends commands to the diverter valves 52 and 54 (the commands may include initiating solenoid current to open or close the valve, or stopping solenoid current to allow normally open valves to open or normally closed valves to close). The diverter valves take some time to move and reach their new state at time C. During this time, the controller updates database 106 (not shown) regarding which pump modules are assigned to which hydraulic circuit sections. Therefore, the controller will begin to consider the pump modules and thus the corrected allocation of the working chamber to the hydraulic circuit section when making the working chamber relocation decision.

[0197] Nevertheless, in some embodiments, during the time period between sending commands to the diversion valve, the controller causes the working chamber of the pump module being redistributed to only begin an inactive cycle, with no net displacement of working fluid. This minimizes the flow rate during the switching process. It is possible that, when making a decision, the controller causes the working chamber of the pump module being switched to only perform an inactive cycle from time A, because once the working chamber has begun an active cycle through the closed LPV, it cannot stop until the shaft has rotated a predetermined angle, and if it is desired to avoid any working chamber from performing an active cycle during the diversion valve switching, the working chamber first needs a certain time period to complete any currently ongoing active cycles. The controller may wait for the working chamber within the pump module to be switched to reach a specific state (phase), and / or wait for the flow rate from the pump module to drop below a specific threshold before activating the diversion valve.

[0198] It is possible that the timing of LPV closure is synchronized with the timing of the flow divider valve movement to delay the active circulation of the working chamber volume until the flow divider valve has completed reconnecting the pump module containing the individual working chambers between the hydraulic circuit sections. Typically, the timing of LPV closure varies because LPV closure is usually much faster than the opening or closing of the flow divider valve.

[0199] Alternatively, the controller may perform one or more active cycles of the working chamber volume before redistributing the pump module from one hydraulic circuit section to another, to intentionally increase the pressure in the high-pressure manifold of the pump module, for example, to approach or reach the pressure of the distribution manifold / input of the hydraulic circuit section to which the pump module will be connected. This reduces transient pressure fluctuations.

[0200] In some embodiments, the switching of the diverter valves is interleaved, that is, it is possible to change from closed to open as a single unit (e.g., Figure 8 , 11 (As shown in the diagram) A valve in a pair of valves remains open until the other valve in the pair has opened; or, a valve that is to be changed from open to closed may remain open until the other valve has closed. This reduces the risk of hydraulic backflow.

[0201] Although the above examples use normally open and normally closed lift valves, other switching mechanisms can be employed. For example, instead of... Figure 8 The arrangement Figure 11 The arrangement uses a pair of double-blocking valves. In fact, Figure 8 The separate check valve has been incorporated into the flow divider valve. A separate check valve is no longer needed, and in this case, it is particularly important to use staggered opening / closing of the valve when switching pump modules between hydraulic circuit sections.

[0202] Figure 12 Another flow divider valve embodiment is shown, which corresponds to Figure 8 The arrangement differs from the previous one, except that a single switchable valve 62 replaces a pair of lift valves 52, 54. The switchable valve has a first position in which the high-pressure manifold 8B of the individual pump module is connected to a first distribution manifold 56 and thus to a first hydraulic circuit portion; a second position in which the high-pressure manifold is connected to a second distribution manifold 58 and thus to a second hydraulic circuit portion; and an intermediate position in which the high-pressure manifold is connected to both but via an orifice. The spool valve is switched between the first and second positions by a controller, and only briefly passes through the intermediate position. Preferably, the high-pressure manifold is briefly connected to both distribution manifolds to avoid hydraulic backflow, rather than the high-pressure manifold not being connected to either distribution manifold; however, in some embodiments, the intermediate position is blocked. A spring biases the valve to be normally open to the first hydraulic circuit portion and normally closed to the second hydraulic circuit portion. This switching arrangement will also be used, for example, to divert flow to a third hydraulic circuit portion, at least according to… Figure 7 , 8 Examples of 11, 12 and 13.

[0203] It will also be possible to use spool valves with multiple positions corresponding to different flow configurations, wherein the spool valves control the pilot flow to a hydraulically actuated valve that opens or closes to allow flow from the high-pressure manifold to one or another hydraulic circuit section, depending on the valve position. Therefore, the flow from the pumping module does not necessarily have to pass through a single spool valve.

[0204] Figure 13 An alternative flow divider unit is demonstrated, employing a multi-position lift valve 66 that can be pilot-operated or solenoid-actuated. As... Figure 12 The valve has first and second positions, wherein a high-pressure manifold is connected to one or more distribution manifolds (and thereby to the corresponding hydraulic circuit section). An intermediate position exists between the first and second positions, wherein the high-pressure manifold is connected to both distribution manifolds but via a throttle valve (and typically also via a check valve to prevent backflow to the high-pressure manifold of the corresponding pump module). The valve passes through the intermediate position very briefly when it is switched from the first position to the second position (and vice versa) by the controller.

[0205] Figure 14 This is a schematic diagram of an alternative configuration of the connection circuit, which enables the pumping module to switch between three different hydraulic circuit sections via manifolds 56, 58, and 250, and thus can be used as... Figure 7 Alternatives to the connection loop. The high-pressure manifold 8A-8H of pump modules 4A-4H can utilize multiple diverter valves 252, which can take any of the forms described above and are under the control of the controller, and another diverter valve 254, also under the control of the controller, in a first distribution manifold 56 connected to the first hydraulic circuit section, a second distribution manifold 58 connected to the second hydraulic circuit section, and a third hydraulic circuit section (in this example, used for the rotation function, depending on...). Figure 7The pump modules 4C to 4H are switched between the connected third distribution manifolds 250. Either pump module can be connected to the first distribution manifold. With the other diverter valve 254 in the shown position, pump modules 4C to 4H are always connected to the second distribution manifold by switching the valve 252 associated with the corresponding pump module to position 2, regardless of the state of the other diverter valve. When the other diverter valve is in the shown state, it connects the switchable manifold portion 256 to the second distribution manifold 58. In this combination, pumps 4A and 4B can be selectively connected to the switchable manifold portion via diverter valve 252 (in position 2), connecting to the second distribution manifold in the shown position and thus to the second hydraulic circuit portion. When the other diverter valve is switched to its alternative state (not shown), the switchable manifold portion is instead connected to the third distribution portion. In this combination, pumps 4A and 4B will be connected to the third hydraulic circuit portion (via the third distribution portion) with diverter valve 252 properly configured to position 2. Pump modules 4A and 4B can thus switch simultaneously between the second and third hydraulic circuit sections via the controller actuating corresponding additional flow divider valves. Alternatively, the pump modules can switch one at a time between the first hydraulic circuit section and the second or third hydraulic circuit section (depending on the position of the other flow divider valve) or switch from the first hydraulic circuit section to the second or third hydraulic circuit section.

[0206] Another diverter valve may be located at different positions along the length of the first or second distribution manifold. For example, if it is located at position 258, it may switch up to four pump modules between the first and third hydraulic circuit sections. If it is located at position 260, it may switch up to seven pump modules between the second and third hydraulic circuit sections.

[0207] Compared to Figure 15A convenient location for the switchable valve (hydraulic connection circuit / distribution valve) is the end plate 66 of the hydraulic machine. In this case, the conduits acting as high-pressure manifolds 8A to 8D for pumps 4A to 4D, passing through the hydraulic machine, are connected to the annular conduit 270 in the end plate. This arrangement is convenient because the conduit extends at right angles to the plane of the end plate. The first and second connection circuit outputs 12, 14 from the hydraulic machine to the first and second hydraulic circuit sections also extend from opposite ends of the annular conduit, respectively. Dual blocking valves 272A to 272F, under the control of the controller, can be selectively closed. In use, both of the dual blocking valves are closed at any time to thereby define the first and second distribution manifolds communicating with the first and second connection circuit outputs and thus the first and second hydraulic circuit sections, as well as with the high-pressure manifolds of the selected pump modules. Thus, pump modules can be selectively connected to one or the other of the hydraulic circuit sections, but with the limitation that multiple pump modules connected to the same hydraulic circuit section must be adjacent around the circumference of the annular conduit. Sections 274 and 276 are connections between the ring conduit and the outputs of the first and second connection circuits, but may also be connected to a conduit through the hydraulic machine that acts as a high-pressure manifold for another pumping module. In this case, there is a pumping module permanently connected to each of the connection circuit outputs, but the remaining pumping modules are switchable.

[0208] Figure 15 Option B illustrates an alternative in which, instead of a ring conduit, a C-shaped conduit 278 exists that communicates with conduits connected to four different pump modules. Any one of the dual stop valves 272A, 272B, and 272C can be closed (three different options are given), while all other stop valves remain open. In the first option, with 272A closed, the pump module with high-pressure manifold 276 is connected to the second output 14, and the pump module with high-pressure manifolds 8A, 8B, and 274 is connected to the first output. In the second option, with 272B closed, the pump module with high-pressure manifold 276 and the pump module with high-pressure manifold 8A are connected to the first manifold, and the pump module with high-pressure manifolds 8B and 274 is connected to the first output. In the third option, with 272C closed, the pump module with high-pressure manifold 276 and the pump module with high-pressure manifolds 8A and 8B are connected to the first manifold, and the pump module with high-pressure manifold 274 is connected to the first output. Controller switching requires dual blocking valves to redistribute the pumping modules.

[0209] exist Figure 15 A and Figure 15 In embodiment B, the third connection circuit output (for the third hydraulic circuit portion) may be connected at any of positions 8A, 8B, 8C, and 8D.

[0210] exist Figure 16In one embodiment, a first distribution manifold 56 extending to the first output 12 and the first hydraulic circuit section input 16, and a second distribution manifold 58 extending to the second output and the second hydraulic circuit section input 18 of the distribution block, are connected together via eight blocking valves 280 connected in series, each blocking valve having a T-joint connection between it and the eight high-pressure manifolds 8A to 8H of the pump modules 4A to 4H. The controller selects to close one blocking valve at a time, thereby splitting the pump module between the distribution to the first and second hydraulic circuit sections depending on the selected blocking valve.

[0211] In the event of an overpressure incident, the equipment typically includes a pressure reducing valve. One is available per pump module, but... Figure 17 In this embodiment, the high-pressure manifold of each of the four pump modules is connected in parallel to a single pressure-reducing valve 290 via a check valve 280. All check valves are upstream of the pressure-reducing valves and perform flow checking when the pressure downstream of the pressure-reducing valves is higher than the high-pressure manifold pressure. Figure 17 Implementations may be provided within or separate from the allocation block.

[0212] In the device described above, problems may arise when the demand for working fluid cannot be met due to competing demands for pump modules, and when the pump modules connected to the connection loop output (and thereby connected to the hydraulic circuit section and / or a group of one or more actuators) are therefore unable to meet the demand; and when one or more additional pump modules are connected to the same connection loop output, thereby increasing the maximum displacement to the connection loop output, due to a further increase (or decrease to other competing demands) in the demand associated with the connection loop output. When this additional capacity becomes available, the actual displacement to the connection loop output (and thereby to the hydraulic circuit section and / or a group of one or more actuators) suddenly jumps, resulting in vibration, jitter, or difficulty in machine control (especially for human operators).

[0213] This reference Figure 18A As shown, Figure 18AThe illustration shows an arrangement where up to eight pump modules of equal capacity can be connected to the connection loop output. The actual flow rate to the connection loop output (solid line) increases linearly over time as the flow demand (dashed line) increases. At time 0, four pump modules are connected to the connection loop output. In this example, there is already sufficient flow demand to one or more other connection loop outputs, such that when the demand exceeds the maximum capacity of the four pump modules (dashed line), at time t1, the actual flow rate remains at the maximum capacity of the four pump modules and decreases below the demand flow rate. As the demand flow rate increases, at time t2, the demand is sufficient relative to other competing demands for the controller to decide to connect a fifth pump module to the connection loop input, resulting in a gradual increase in capacity. At this point, as shown by the solid line, the actual flow rate suddenly jumps as the five pump modules operating below the maximum combined flow rate can accurately meet the demand. This jump can lead to vibration, jitter, and control difficulties. Figure 18A As shown, the actual shift will be limited again at time t3, and then jump upwards again at time t4 when the 6th pump module is allocated.

[0214] In the first approach, we have found that once total demand exceeds a threshold, these shift jumps can be avoided by scaling down the demand signal by multiplying it by a scaling factor.

[0215] The threshold is set once the total demand exceeds the maximum shift of all pump modules except one in (a) pump module.

[0216] The scaling factor ensures that the total demand does not exceed the maximum displacement of all pump modules except one in (a) the pump module. This is a fraction of the maximum possible displacement, equal to the maximum displacement of all pump modules except one in (a) the pump module divided by the maximum displacement of all pump modules in (c) the pump module (assuming all pump modules can be connected to any output).

[0217] In this example, with 8 pump modules having the same maximum shift, this has the following effect: if the total demand exceeds 7 / 8 of the maximum shift, the total demand scaled back will not exceed 7 / 8 of the maximum shift.

[0218] Therefore, the scaling factor is (a) the maximum shift of all pump modules except one in the pump module divided by (b) the sum of the demands.

[0219] Once the demand scales in this way, it will appear as if the demand has been scaled down proportionally. Figure 18B As demonstrated, not only does the scaled demand signal never exceed the available capacity, but there are also no sudden shifts or jumps as additional pump modules are connected to the connection loop output.

[0220] This is particularly applicable when allocating a fraction of the available pump modules to each connected circuit output / hydraulic circuit section in proportion to the hydraulic fluid demand of that output / hydraulic circuit section, typically rounded to the nearest integer.

[0221] refer to Figure 19 The effect of scaling the ratio is that, in practice, a shift equal to the capacity of one of the pump modules is never used. In this diagram, the line labeled Output 1 is the scaled-back demand signal of one of the two connected loop outputs, the line labeled Output 2 is the scaled-back demand signal assigned to the other of the two connected loop outputs, and the dashed line represents the machine's unused capacity, which is the capacity of one pump module. At the precise locations shown, three pump modules are connected to Output 1, and five pump modules are connected to Output 2, without exceeding the maximum shift of either output. While this does reduce the maximum capacity, it avoids discontinuities in the shift.

[0222] Example - First Method

[0223] The pump has 24 working chambers, grouped into 8 pump modules. Each pump module consists of 3 working chambers sharing a common high-pressure manifold. Half of the working chambers and pump modules are located within one housing, and the other half within another housing, with the working chambers sharing a common shaft. The maximum displacement of each pump module is 24 cc per revolution of the pump's rotatable shaft, thus the total maximum displacement of the machine is 192 cc per revolution. The 8 pump modules can be connected via a connection circuit to either of two connection circuit outputs (or hydraulic circuit sections).

[0224] The capacity of a single pump module is not used, and the demand is scaled back as needed so that the total demand does not exceed 7 / 8 x 192 = 168 cc / turn (threshold). When the demand is for a total shift that can be output by all but one of the pump modules in combination, this is equivalent to multiplying the individual demand by 168 cc / turn and dividing by the total demand.

[0225] In one example, during operation, the demand for the outputs is 100cc / cycle for output 1 and 150cc / cycle for output 2, with 100 and 150 being 0.4 and 0.6 of the total demand, respectively. The sum of these demands is 250cc / cycle, which exceeds the threshold of 168cc / cycle. Accordingly, the demand will be scaled down so that its sum is 168cc / cycle.

[0226] The total available pump capacity is proportionally divided among each supply, and the demand scaled back to 0.4 x 168 cc / cycle = 67.2 cc / cycle and 0.6 x 168 cc / cycle = 100.8 cc / cycle. This is equivalent to multiplying the original demand (100 cc / cycle and 150 cc / cycle) by 168 cc / 250 cc = 0.672.

[0227] Next, the number of pump modules required to connect to each output is calculated by dividing the rounded demand by the capacity of each pump module. Therefore, 67.2 / 24cc / turnover = 2.8, rounded up to 3 pump modules, and 100.8 / 24cc / turnover = 4.2, rounded up to 5 pump modules. For verification, these numbers should equal the total number of pump modules, which is 8.

[0228] This method ensures that there will never be a sudden increase in displacement due to a new pump module being connected to the output. Scaled demand is never saturated.

[0229] Reference Figures 20A to 20F In a further complication of the method described above, each connection loop output (regardless of whether it leads to a hydraulic circuit section and / or a group of one or more actuators) is allocated a minimum fraction of the available pump module capacity (or, when pump modules have the same capacity), equal to the reciprocal of the number of connection loop outputs. This applies when the demand is sufficiently high (e.g., exceeding the total possible displacement), or when each demand exceeds the reciprocal of the number of connection loop outputs with the maximum possible displacement. Typically, this second method is applied only under demand higher than that triggering the first method, and a demand zone may exist between the two, in which only the first method is applied or a transitional method exists.

[0230] Example - Second Method

[0231] In the following example, there are two outputs and eight pump modules, each of which has a capacity of 24cc / cycle.

[0232] exist Figure 20A and 20D In the first example shown, both the first demand (labeled Output 1) and the second demand (labeled Output 2) target more than half of the available shift; in fact, the first demand targets the entire available shift alone. Each of the two outputs is allocated 100 / 2% = 50% of the available capacity and is therefore allocated 4 pump modules, where the first and second demands are scaled back to 50% of the total available shift.

[0233] exist Figure 20B and 20EIn the second example shown, the first demand (output 1) again targets more than half of the available shift, but now the second demand (output 2) targets less than half of the available shift. The first output is allocated 100 / n = 50% of the available capacity, and therefore 8 / 2 = 4 pump modules. The second output is allocated the remaining capacity, and therefore also 4 pump modules. Figure 20E The dashed lines in the diagram represent a small amount of lost capacity.

[0234] exist Figure 20C and 20F In the third example shown, the first demand (output 1) is still high, and the second demand is low enough that 8 / 2 = 4 pump modules are not needed to satisfy it. In this case, the second output is allocated a sufficient number of pump modules to satisfy the complete second demand (2 in this case), and the remainder (6) is allocated to the remaining pump modules.

[0235] More specifically, the allocation in the third instance can be calculated using the following method.

[0236] The requirement for output 1 is 192cc per cycle (full pump capacity, which will require all 8 pump modules).

[0237] The output requirement for 2 is 36cc per cycle (far less than half the pump capacity, which can be achieved using 1.5 pump modules).

[0238] Total demand = 228cc / turnover

[0239] The following algorithm is used to process output 1:

[0240] IF(36cc / rev<(0.5n-1)*24cc / rev)[statement is true]

[0241] Output 1 displacement allocation=MIN(192cc / rev,192cc / rev-24cc / rev-36cc / rev)= 132cc / rev

[0242] ELSE

[0243] Output 1 displacement allocation=MIN(Output 1 Demand, equal fraction of maximum output capacity)

[0244] The requirements for output 2 are processed as follows:

[0245] IF(192cc / rev<(0.5n-1)*24cc / rev)[statement not true]

[0246] Output 2 displacement allocation=MIN(Output 2 demand,Total pumpcapacity-1-Output 1 demand)

[0247] ELSE

[0248] Output 2 displacement allocation=MIN(36cc / rev,96cc / rev) =36cc / rev

[0249] Therefore, the demand for output 1 is scaled to 132cc / cycle, and output 1 is allocated 6 pump modules, while the demand for output 2 is maintained and output 2 is allocated 2 pump modules.

[0250] Thus, each output is assigned a pump module capable of providing (as a minimum) an equal fraction of the total shift capacity when it has a demand for at least one equal fraction of the total shift capacity, and more pump modules may be assigned if other demands permit.

[0251] The benefit of combining this second guaranteed fractional method (guaranteeing half in the case of two outputs) with the first method is that the pump's full capacity can be used for longer periods, resulting in faster operation (faster duty cycle time). It will also significantly reduce the number of switching cycles required from the connecting loop valves, thereby increasing system lifespan. The disadvantage is that there is some loss of controllability when compared to the first strategy.

Claims

1. An apparatus comprising: First and second hydraulic circuit sections, The first hydraulic circuit section has a first hydraulic circuit section input and a plurality of valves configured to regulate the flow rate of hydraulic fluid from the first hydraulic circuit section input to each of a first group of at least two hydraulic actuators. The second hydraulic circuit section has a second hydraulic circuit section input and a plurality of valves configured to regulate the flow rate of hydraulic fluid from the second hydraulic circuit section input to each of a second group of at least two hydraulic actuators. prime mover A hydraulic machine having a rotatable shaft driven by a prime mover and including at least three working chambers having a volume that cyclically changes with the rotation of the rotatable shaft, each working chamber including a low-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a low-pressure manifold, and a high-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a high-pressure manifold, wherein the working chambers are configured as a plurality of pump modules, each pump module including a group of one or more of the working chambers and a high-pressure manifold common to each working chamber in the group. A hydraulic connection circuit includes multiple connection circuit inputs, each of which is in fluid communication with a high-pressure manifold of a corresponding pump module. A first connection circuit output is in fluid communication with a first hydraulic circuit portion input, and a second connection circuit output is in fluid communication with a second hydraulic circuit portion input. The hydraulic connection circuit is configured to connect each of the connection circuit inputs to the connection circuit output and includes multiple valves switchable to change the connection circuit output to which each connection circuit input is connected, such that each pump module is connected to one hydraulic circuit portion at a time, and for some or all of the pump modules, the connection portion to which the corresponding pump module is connected can be changed. A controller configured to actively control at least the low-pressure valve of the working chamber to determine the net displacement of each working chamber during each cycle of the working chamber volume, and the valve such that, in response to a first demand for hydraulic fluid in the first hydraulic circuit section, the net displacement of the working chamber of each pump module connected to the first hydraulic circuit section is controlled, and in response to a non-dependent second demand for hydraulic fluid in the second hydraulic circuit section, the net displacement of the working chamber of each pump module connected to the second hydraulic circuit section is controlled; and The device is configured such that when a pump module switches from being connected to one hydraulic circuit section to another, the working chamber of the corresponding pump module performs only an inactive cycle during the valve switching, and / or does not cause the working chamber to begin any active cycle.

2. The device of claim 1, wherein the first hydraulic circuit portion includes a first valve block portion and the second hydraulic circuit portion includes a second valve block portion, the first and second valve block portions being part of a metal block in which the valve is located, and each of the first and second valve block portions each includes a port that serves as an input to the first or second hydraulic circuit portion, respectively.

3. The device according to claim 1 or 2, wherein the valve is an electrically controllable diverter valve for dedicatedly connecting the high-pressure port of the pump module to the first connection loop output or the second connection loop output.

4. The device according to claim 1 or 2, wherein the controller controls at least the low-pressure valve of the working chamber to determine whether each working chamber experiences an active cycle or an inactive cycle for each cycle of the working chamber volume, the active cycle having a net displacement of the working fluid between the low-pressure manifold and the high-pressure manifold of the working chamber, and the inactive cycle not having a net displacement of the working fluid between the low-pressure manifold and the high-pressure manifold of the working chamber.

5. The device of claim 1 or 2, wherein the device comprises one or more additional hydraulic circuit sections, each additional hydraulic circuit section having a corresponding hydraulic circuit section input, and one or more additional hydraulic actuators, wherein the hydraulic connection circuit further comprises, for each additional hydraulic circuit section, another connection circuit output in fluid communication with the corresponding hydraulic circuit section input, wherein the plurality of valves of the hydraulic connection circuit are switchable to connect the high-pressure manifold of each corresponding pump module to one or the other of the connection circuit outputs at one time.

6. The device according to claim 1 or 2, wherein each of the hydraulic circuit portions includes at least one proportional valve, the proportional valve being controllable to divert a proportion of the working fluid received by the hydraulic circuit portion to one or more actuators.

7. The device according to claim 1 or 2, wherein the first and / or second hydraulic circuit portion further comprises a hydraulic conduit providing a path for hydraulic fluid to flow from the hydraulic circuit portion input to at least one actuator of the hydraulic circuit portion, without passing through a proportional valve of the hydraulic circuit portion and a controllable bypass valve selectively allowing fluid flow through the hydraulic conduit, such that hydraulic fluid can be selectively supplied to the at least one actuator from the hydraulic circuit portion input via one or more proportional valves or via the hydraulic conduit.

8. The device of claim 7, wherein hydraulic fluid is supplied to the at least one actuator from the hydraulic circuit portion via one or more proportional valves and the hydraulic conduit.

9. The device of claim 1 or 2, wherein the high-pressure manifold of some or all of the pump modules is connected to the first hydraulic circuit portion via a first valve and to the second hydraulic circuit portion via a second valve, wherein the controller interleaves the switching of the first and second valves to prevent both from closing simultaneously.

10. The device of claim 9, wherein one of the first and second valves is a normally open valve and the other is a normally closed valve.

11. The device of claim 1 or 2, wherein the hydraulic connection circuit includes a conduit extending between the first and second connection circuit outputs and having a plurality of fluid joints along the length of the conduit, each joint being connected to a different connection circuit input; and a plurality of blocking valves controllable to selectively block the conduit and thereby determine which connection circuit inputs are connected to which connection circuit outputs.

12. The device of claim 11, wherein the conduit extends along a closed loop from the first connection loop output to the second connection loop output and back to the first connection loop output, wherein the junction and the blocking valve are distributed around the loop.

13. The device of claim 1 or 2, wherein the hydraulic connection circuit includes a first manifold portion extending to the output of the first connection circuit, a second manifold portion extending to the output of the second connection circuit, a third manifold portion extending to the output of the third connection circuit to an input of a third hydraulic circuit portion comprising one or more actuators, and a switching manifold portion, wherein at least the first manifold portion, the second manifold portion, and the switching manifold portion are each selectively connected to one or more of the connection circuit inputs via one or more valves, and wherein the hydraulic connection circuit further includes a manifold diverter valve controllable to connect the switching manifold portion to the first manifold portion or the third manifold portion.

14. The device of claim 1 or 2, wherein the high-pressure manifold of some or all of the pump modules is connected to a first connection loop output via a first valve and to a second connection loop output via a second valve, and wherein the controller interleaves the switching of the first and second valves to prevent both from closing simultaneously.

15. The device according to claim 1 or 2, wherein the device is configured such that when the pump module switches from being connected to a connection loop output, the working chamber of the respective pump module performs an inactive cycle when the valve is switched.

16. A method of operating a device, the device comprising: First and second hydraulic circuit sections, The first hydraulic circuit section has a first hydraulic circuit section input and a plurality of valves configured to regulate the flow rate of hydraulic fluid from the first hydraulic circuit section input to each of a first group of at least two hydraulic actuators. The second hydraulic circuit section has a second hydraulic circuit section input and a plurality of valves configured to regulate the flow rate of hydraulic fluid from the second hydraulic circuit section input to each of a second group of at least two hydraulic actuators. prime mover A hydraulic machine having a rotatable shaft driven by a prime mover and including at least three working chambers having a volume that cyclically changes with the rotation of the rotatable shaft, each working chamber including a low-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a low-pressure manifold, and a high-pressure valve for regulating the flow rate of hydraulic fluid between the working chamber and a high-pressure manifold, wherein the working chambers are configured as a plurality of pump modules, each pump module including a group of one or more of the working chambers and a high-pressure manifold common to each working chamber in the group. A hydraulic connection circuit includes multiple connection circuit inputs, each of which is in fluid communication with the high-pressure manifold of a corresponding pump module. A first connection circuit output is in fluid communication with a first hydraulic circuit section input, and a second connection circuit output is in fluid communication with a second hydraulic circuit section input. The hydraulic connection circuit is configured to connect each of the connection circuit outputs to the hydraulic circuit section inputs and includes multiple valves switchable to change the connection circuit output to which the hydraulic circuit section input is connected, such that each pump module is connected to one hydraulic circuit section at a time, and for some or all of the pump modules, the hydraulic circuit section to which the corresponding pump module is connected can be changed. The device is configured such that when a pump module switches from being connected to one hydraulic circuit section to another, the working chamber of the corresponding pump module only performs an inactive cycle during the valve switching, and / or does not cause the working chamber to begin any active cycle. The method includes: Actively control the low-pressure valve of at least the working chambers to determine whether each working chamber experiences an active or inactive cycle, the active cycle having a net displacement of working fluid between the low-pressure manifold and the high-pressure manifold of the working chamber, and the inactive cycle not having a net displacement of working fluid between the low-pressure manifold and the high-pressure manifold of the working chamber, and the valves such that, in response to a first demand for hydraulic fluid in the first hydraulic circuit section, the net displacement of the working chamber of each pump module connected to the first hydraulic circuit section is controlled, and in response to a non-dependent second demand for hydraulic fluid in the second hydraulic circuit section, the net displacement of the working chamber of each pump module connected to the second hydraulic circuit section is controlled. The portion of the hydraulic circuit to which the pump module is connected is changed by switching one or more of the valves in the hydraulic connection circuit. And causing the working chamber of the corresponding pump module to only perform an inactive cycle when the corresponding pump module switches from being connected to one hydraulic circuit section to another hydraulic circuit section, and / or not causing the working chamber to start any active cycle.

17. The method of claim 16, wherein a regulation demand signal is output in response to a change in the hydraulic circuit portion and / or connection circuit to which the pump module is connected, to prevent a sudden increase in the net displacement of the working fluid to the hydraulic circuit portion and / or connection circuit portion exceeding a threshold.

18. The method of claim 16 or 17, wherein at least when multiple demands for hydraulic fluid associated with the one or more actuators in fluid communication with a corresponding hydraulic circuit section or a corresponding connection circuit output make it impossible to satisfy the multiple demands simultaneously, regardless of which pump modules are connected to which hydraulic circuit sections or connection circuit outputs, some or all of the multiple demands are proportionally reduced by multiplying by a scaling factor, such that they total at most equal to the maximum displacement rate simultaneously achievable by all but one of the pump modules that can be connected to individual hydraulic circuit or connection circuit outputs.

19. The method of claim 18, wherein the scaling factor is or at most (a) the ratio of the maximum shift rate simultaneously achieved by all but one of the pump modules that can be connected to the output of an individual hydraulic circuit or connection circuit to (b) the sum of the plurality of demands.

20. The method of claim 16 or 17, wherein there are n demands for hydraulic fluid from a corresponding hydraulic circuit portion or one or more actuators connected to a corresponding connection circuit output, and when the n demands make it impossible to satisfy all n demands simultaneously regardless of which pump modules are connected to which connection circuit outputs, if one of the n demands is for a maximum displacement of more than (100 / n)% for the pump module that can be connected to the corresponding hydraulic circuit portion or connection circuit output, then the corresponding hydraulic circuit portion or connection circuit output has a pump module connected thereto capable of delivering at least (100 / n)% of the maximum displacement.

21. The method of claim 20, wherein n=2.

22. The method of claim 20, wherein if one of the requirements is less than (100 / n)% but higher than a threshold for the maximum displacement of the pump module, each hydraulic circuit portion or connecting circuit portion has a pump module connected thereto capable of delivering at least (100 / n)% of the maximum displacement.

23. The method of claim 22, wherein if one of the demands is below the threshold, the demands are scaled down such that they total at most the maximum displacement rate achieved by all but one of the pump modules that can be connected to any of the hydraulic circuit section or the connection circuit output.

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