Passive piston hydraulic device with partition

A hydraulic device having: a housing; a bore of the housing having a first piston positioned therein for a first reciprocal motion within the bore along a bore axis; a mechanical element coupled to the first piston for either driving the first reciprocal motion or being driven by the first reciprocal motion; a second piston positioned in the bore for a second reciprocal motion within the bore along the bore axis; a hydraulic fluid chamber of the bore positioned between the first piston and the second piston, the hydraulic fluid chamber having a hydraulic fluid inlet and a hydraulic fluid outlet; a chamber of the bore positioned between the second piston and a wall of the housing, the chamber for having a resilient element therein; a separator partition dividing the hydraulic fluid chamber into a first hydraulic fluid chamber and a second hydraulic fluid chamber, the separator partition positioned in the bore between the hydraulic fluid inlet and the second piston, the separator partition having a first fluid passageway for fluidly coupling the first hydraulic fluid chamber with the second hydraulic fluid chamber; and a valve for controlling flow in the first fluid passageway of hydraulic fluid between the first hydraulic fluid chamber and the second hydraulic fluid chamber.

FIELD OF THE INVENTION

The present disclosure relates to the field of hydraulic piston operated devices, and in particular the pistons used in such devices.

BACKGROUND

Current hydraulic devices can suffer from operational efficiencies due to the required movement of their piston(s) as a result of inlet/outlet fluid pressures to the device and influence of a drive mechanical component or driven mechanical component operatively coupled to one or more of the piston(s). In particular, current hydraulic devices only provide for coupled movement of multiple piston arrangements, such that the movement of the pistons is done at the same time due to influence of the hydraulic fluid movement and/or the mechanical component(s).

SUMMARY

There is a need for a hydraulic device that provides improved hydraulic performance.

In one embodiment, provided is a hydraulic device having: a housing; a bore of the housing having a first piston positioned therein for a first reciprocal motion within the bore along a bore axis; a mechanical element coupled to the first piston for either driving the first reciprocal motion or being driven by the first reciprocal motion; a second piston positioned in the bore for a second reciprocal motion within the bore along the bore axis; a hydraulic fluid chamber of the bore positioned between the first piston and the second piston, the hydraulic fluid chamber having a hydraulic fluid inlet and a hydraulic fluid outlet; a chamber of the bore positioned between the second piston and a wall of the housing, the chamber for having a resilient element therein; a separator partition dividing the hydraulic fluid chamber into a first hydraulic fluid chamber and a second hydraulic fluid chamber, the separator partition positioned in the bore between the hydraulic fluid inlet and the second piston, the separator partition having a first fluid passageway for fluidly coupling the first hydraulic fluid chamber with the second hydraulic fluid chamber; and a valve for controlling flow in the first fluid passageway of hydraulic fluid between the first hydraulic fluid chamber and the second hydraulic fluid chamber.

DETAILED DESCRIPTION

The following relates to a hydraulic device for use as a hydraulic pump and/or a hydraulic motor configured as a piston type device (e.g. reciprocating type device). Examples of hydraulic systems incorporating such pump/motors can include, but are not limited to, a brake system, a drive system, etc.

An example hydraulic device is shown inFIG. 1and is indicated generally at numeral10. The hydraulic device10can be coupled to a mechanical element12(e.g. one end of a connecting rod connected a common driveshaft—not shown) for either driving reciprocal motion (when operated as a hydraulic motor) of a first piston20or being driven (when operated as a hydraulic pump) by the reciprocal motion. For example, when in brake mode, the rotational motion of the driveshaft is transferred to reciprocating motion40of the first piston20via the mechanical element12(e.g. connecting rod). When in drive mode, the reciprocating motion40of the first piston20can be transferred to rotational motion of the driveshaft via the mechanical element12(e.g. connecting rod).

In alternative, the first piston20(or driver/driven piston) can include a surface19that is shaped to receive a bearing mechanism that provides for the transfer of power between the mechanical element12(e.g. connecting rod) and the first piston20and that allows for the first piston20to decouple from the mechanical element12(e.g. connecting rod). For example, the mechanical element12can be a cam surface in contact with the first piston20, such that the cam surface can decouple from the surface19of the first piston20during selected portions of the intake and exhaust cycle of the hydraulic device10.

The hydraulic device10includes a main body or housing16. Within the housing16, the hydraulic device10includes the first piston20and a second piston22that define a hydraulic fluid chamber24between them, separated into a first hydraulic chamber24aand a second hydraulic chamber24bby a separator partition21, as further described below. A bore18of the housing16receives the first piston20therein for a first reciprocal motion40within the bore18along a bore axis14. The bore18also receives the second piston22therein for a second reciprocal motion42within the bore18along the bore axis14, such that the first reciprocal motion40and the second reciprocal motion42can be decoupled from one another as further described below.

For example, the first reciprocal motion40and the second reciprocal motion42can be configured for acting in both a same direction and an opposite direction along the bore axis14during respective portion(s) of an intake and exhaust cycle of the hydraulic device10.

It is noted that hydraulic fluid25can be at the same or different fluid pressures in the different hydraulic chambers24a,b, depending upon hydraulic fluid25communication between the hydraulic chambers24a,b, as discussed. Also, located between the second piston22and a wall of the housing16is a resilient chamber26for containing a resilient element27(e.g. compressible fluid such as air). As such, reciprocation42of the second piston22along the bore axis14is dictated by a resulting force differential between the hydraulic fluid25(in the second hydraulic chamber24b) acting on a first face22aof the second piston22and the resilient element27(in the resilient chamber26) acting on the second face22b. For example, it is understood in the case where the resilient element27is air, the direction of the reciprocal motion42will be dependent upon which of the resilient element27or the hydraulic fluid25has the greater pressure (e.g. pressure of hydraulic fluid25greater than pressure of resilient element27would result in motion of the second piston22away from the separator partition21, pressure of hydraulic fluid25less than pressure of resilient element27would result in motion of the second piston22towards the separator partition21, pressure of hydraulic fluid25equal to pressure of resilient element27would result in a stationary position of the second piston22with respect to the separator partition21). As such, the second piston22can be referred to as a passive or floating piston and the first piston20can be referred to as an active or main piston, as the second piston22is not connected (e.g. is unconnected) to any mechanical drive elements (as is the first piston20).

Referring again toFIG. 1, the hydraulic device10, the hydraulic fluid chamber24of the bore18is positioned between the first piston20and the second piston22, the hydraulic fluid chamber24having a hydraulic fluid inlet30for providing access of the hydraulic fluid25into the first hydraulic chamber24aand a hydraulic fluid outlet32for providing egress of the hydraulic fluid25out of the first hydraulic chamber24a. For example, the hydraulic fluid outlet32can be located in the wall of the housing16between the separator partition21and the first piston20. Ingress and egress of the hydraulic fluid25with respect to the first hydraulic chamber24acan be controlled by one or more valves34. Also provided is the separator partition21dividing the hydraulic fluid chamber24into the first hydraulic fluid chamber24aand the second hydraulic fluid chamber24b, such that the separator partition21is positioned in the bore18between the hydraulic fluid inlet30and the second piston22. The separator partition21has a first fluid passageway36for fluidly coupling the first hydraulic fluid chamber24awith the second hydraulic fluid chamber24band a valve38for controlling flow in the first fluid passageway36of hydraulic fluid25between the first hydraulic fluid chamber24aand the second hydraulic fluid chamber24b.

The housing16can also have an optional passageway39(in the case where the resilient element27is a compressible fluid such as air), which can provide for an amount of the resilient element27to pass into and/or out of the resilient chamber26(e.g. controlled via valve44). It is recognised that the resilient chamber26can have a fixed amount of the resilient element27deposited therein and/or can have a variable amount of the resilient element27deposited therein as controlled via a resilient element supply (e.g. air supply—not shown) in combination with the control valve44. For example, controlled variation in the amount of the resilient element27contained in the resilient chamber26can be used to affect the rate and/or direction of the reciprocal motion42of the second piston22, as desired.

The resilient element27can be any element that is operable to convert kinetic energy to potential energy and vice versa. Examples of resilient elements27that can be used include a spring. The resilient element27can be a compressible medium such as an air bag or a gas, such as nitrogen, that will then be contained within the closed resilient chamber26(e.g. container). For example, the passageway/opening39can be closed (via valve44) to contain the resilient element27within the second cavity26. For example, the resilient element27can be connected to an external resistance control element, not shown, such as, for example, a source of compressed air, that can adjust the amount of the resilient element27in the resilient chamber26in order to affect the movement of the second piston22.

Referring again toFIG. 1, the hydraulic device10can also have a second hydraulic fluid outlet46for exhausting hydraulic fluid25out of the second hydraulic chamber24b, such that the second hydraulic fluid outlet46is separate from the first hydraulic fluid outlet32(e.g. controlled via second control valve48). As shown inFIG. 1, the second hydraulic fluid outlet46can be connected to a second fluid passageway50in the separator partition21. In an alternative embodiment, as shown inFIG. 2, the second hydraulic fluid outlet46can be positioned in a wall of the housing16and as such is independent from the separator partition21. It is recognised that in both embodiments shown inFIGS. 1 and 2, the hydraulic fluid outlet46provides for the exhausting of the hydraulic fluid25from the second hydraulic fluid chamber24band out of the bore18.

In a further alternative embodiment, as shown inFIG. 3, the second hydraulic fluid outlet46can be connected to the fluid passageway36in the separator partition21, such that the fluid passageway36provides for both ingress and egress of the hydraulic fluid25into and out of the second hydraulic fluid chamber24b, as controlled via the (e.g. multi-position) control valve48. In this embodiment, via the control valve48, there is the option of exhausting the hydraulic fluid25out of the second hydraulic chamber24band out of the bore18via second fluid passageway50, and/or exhausting the hydraulic fluid25out of the second hydraulic chamber24band into the first hydraulic chamber24avia fluid passageway36for subsequent egress out of the bore18via hydraulic fluid outlet32.

In a further alternative embodiment, as shown inFIG. 4, both the ingress and egress of the hydraulic fluid25with respect to the second hydraulic chamber24bcan be through fluid passageway36as controlled via control valve38. In this example, the expulsion of hydraulic fluid25out of hydraulic chamber24band out of hydraulic chamber24aare both via hydraulic fluid outlet32. Referring toFIG. 5, shown is a further alternative embodiment such that there can be multiple fluid passageways36and/or multiple fluid passageways50in the separator partition21, as desired.

It is recognised that flow of the hydraulic fluid25in each of the passageways36,50can be controlled via respective control valves38,48, as desired. For example, the control valves38,48can be valves such as but not limited to check valves, an electrically actuated valve, a spool valve, etc.

Referring toFIG. 1, shown is a linear configuration of the bore18with respect to the pistons20,22and their respective reciprocal motions40,42. Referring toFIGS. 6 and 7, shown are bore18embodiments such that the bore axis14is divided into a first axis portion14afor the first reciprocal motion40and a second axis portion14bfor the second reciprocal motion42. InFIG. 6the first axis portion14aand the second axis portion14bare at an (e.g. acute) angle with respect to one another. InFIG. 7, the first axis portion14aand the second axis portion14bare separate and offset (e.g. parallel) to one another. As such,FIG. 7shows the alternative embodiment of the hydraulic device10with first and second pistons20,22in a side by side configuration. The hydraulic device10includes the central bore18that is operable to receive the first piston20and the second piston22, both of which are operable to reciprocate within the central bore18(e.g. bore18for the chamber24aand bore18of the chamber24b). The central bore is U-shaped and includes several turns within it. Each of the first and second pistons20,22are operable to reciprocate within the bore18along their axis14a,b. First piston20reciprocates within central bore18along axis14aand second piston22reciprocates within central bore18along axis14b. As can be seen inFIG. 7, axis14acan be offset from axis14b.

Turning toFIG. 6the alternative embodiment of the hydraulic device10is shown with the hydraulic device10including the housing16having a central bore18. In this embodiment the pistons20,22are operating at an (e.g. 90°) angle to each other. The operation of the hydraulic device10is still, as per the above description. As can be seen inFIG. 6, first piston20reciprocates within central bore18along axis14aand second piston22reciprocates within central bore18along axis14b. Axis14aand axis14bare in a non-parallel configuration, and in fact can be located at 90° relative to each other.

Each of the first piston20and the second piston22can also include a piston seal, indicated generally inFIGS. 6 and 7at numeral52. The piston seal52is operable to trap gas/hydraulic fluid within the respective chambers26,24and to inhibit bleed through into the other of the chambers26,24or out of the chambers26,24, as desired. For example, the piston seal52inhibits the mixing of the fluid25with the resilient element27(e.g. compressible gas) in either of the chambers24b,26(e.g. hydraulic fluid25into chamber26and/or compressible gas27into chamber24b,24a). As well, the seal52can inhibit leakage of the hydraulic fluid25out of the chamber24aand into a crankcase (not shown) containing the mechanical element19.

Referring toFIG. 8, a control unit80can be programmed (e.g. a computer having a set of stored instructions executable by a computer processor) to operate the valves34,38,48in a predefined order, so as to effect operation of the device10as a hydraulic pump or as a hydraulic motor. Further, the injection of hydraulic fluid25with respect to the chambers24a,bcan be performed simultaneously or the injection of the hydraulic fluid25can be restricted to one of the chambers24a,bas facilitated by opening and closing of selected valves34,38,48. Further, the ejection of hydraulic fluid25with respect to the chambers24a,bcan be performed simultaneously or the ejection of the hydraulic fluid25can be restricted from only one of the chambers24a,bat a time, as facilitated by the opening and closing of selected valves34,38,48. Pump mode operation is where the mechanical element12drives the piston20, while motor mode is where the mechanical element12is driven by the piston20.

For example, referring toFIG. 9, valve34of the fluid inlet30can be opened and valve34of the fluid outlet32can be closed to allow for the entry of the hydraulic fluid25into the chamber24ato fill chamber24a, while restricting entry of the hydraulic fluid25into the chamber24bvia passageway36by keeping valve38closed at the same time. In this manner of valve34,38operation, chamber24aexperiences hydraulic fluid25filling (e.g. either by draw action of piston20due to pump mode operation or by injection of pressurized hydraulic fluid25forcing piston20downwards due to motor operation, both modes having the piston20moving away from the partition21), while at the same time filling of chamber24bby the hydraulic fluid25is restricted. In effect, the device10operates as if the chamber24band the floating piston22are isolated from influence by/of the hydraulic fluid25in the chamber24ain either pump mode or motor mode of the hydraulic device10.

For example, referring toFIG. 10, valve34of the fluid inlet30can be opened and valve34of the fluid outlet32can be closed to allow for presence of the hydraulic fluid25in chamber24a, while also allowing entry of the hydraulic fluid25into the chamber24bvia passageway36by keeping valve38open. In this manner of valve34,38operation, chamber24aexperiences hydraulic fluid25presence (e.g. injection of pressurized hydraulic fluid25forcing piston20downwards away from the partition21due to motor operation), thus providing for entry of the hydraulic fluid into the chamber24b. In effect, the device10operates as if the chamber24band the floating piston22are influenced by the hydraulic fluid25present in the chamber24ain motor mode of the hydraulic device10.

For example, referring toFIG. 11, valve34of the fluid inlet30can be closed and valve34of the fluid outlet32can be closed to allow for presence of the hydraulic fluid25in chamber24a, while also allowing entry of the hydraulic fluid25into the chamber24bvia passageway36by keeping valve38open. In this manner of valve34,38operation, chamber24aexperiences hydraulic fluid25presence (e.g. power stroke in pump mode of the device10by forcing piston20upwards—towards the partition21due to being driven by the mechanical element12), thus providing for entry of the hydraulic fluid25into the chamber24b. In effect, the device10operates as if the chamber24band the floating piston22are influenced by the hydraulic fluid25present in the chamber24ain pump mode of the hydraulic device10.

Referring toFIG. 12, valve34of the fluid inlet30can be closed and valve34of the fluid outlet32can be open to allow for the exit of the hydraulic fluid25out of the chamber24a, while restricting exit of the hydraulic fluid25out of the chamber24bvia outlet46by keeping valve38,48closed at the same time. In this manner of valve34,38,48operation, chamber24aexperiences hydraulic fluid25emptying (e.g. by push action of piston20moving towards the partition21), while at the same time chamber24bretains its hydraulic fluid25despite effect of biasing the piston22towards the partition21by the resilient element27in chamber26. In effect, the device10operates as if the chamber24band the floating piston22are isolated from influence by/of the hydraulic fluid25exiting the chamber24ain either pump mode or motor mode of the hydraulic device10.

Referring toFIG. 13, valve34of the fluid inlet30can be closed and valve34of the fluid outlet32can be open to allow for the exit of the hydraulic fluid25out of the chamber24a, while allowing exit of the hydraulic fluid25out of the chamber24bvia outlet46by opening valve48(e.g. with valve38closed) at the same time. In this manner of valve34,38,48operation, chamber24aexperiences hydraulic fluid25emptying (e.g. by push action of piston20moving towards the partition21), while at the same time chamber24bexpels its hydraulic fluid25by push action of piston22moving towards (e.g. under influence of the stored energy of the resilient element27) the partition21. In effect, the device10operates as if the chamber24band the floating piston22contribute to the hydraulic fluid25exiting the combined chamber24in either pump mode or motor mode of the hydraulic device10.

Referring toFIG. 14, valve34of the fluid inlet30can be open and valve34of the fluid outlet32can be closed to allow for the entry of the hydraulic fluid25in to the chamber24a, while allowing exit of the hydraulic fluid25out of the chamber24bvia outlet46by opening valve48(e.g. with valve38closed) at the same time. In this manner of valve34,38,48operation, chamber24aexperiences hydraulic fluid25entry (e.g. by draw action of piston20moving away from the partition21or by injection via motor mode), while at the same time chamber24bexpels its hydraulic fluid25by push action of piston22moving towards the partition21under effect of the bias provided by the resilient element27. In effect, the chambers24a,24bcan be operated independently with respect to entry or exit of their respective hydraulic fluid25in their respective chambers24a,b, as desired.

It is also recognised in operation of the valves34,38,48via the control unit80, in view ofFIG. 2, that the exit of hydraulic fluid25from the chamber24bcan pass through the bore18wall and not through the partition21. It is also recognised, in view ofFIGS. 3 and 4that the exit of hydraulic fluid25from the chamber24bcan pass through the chamber24abefore eventually exiting via fluid outlet32, as desired.

In view of the above operation of the control unit80and the respective valves34,38,48, it is recognised that the pistons20,22can move independently from one another. For example, the piston20can move towards the partition21(e.g. under influence of the mechanical element12) while the piston22remains stationary (e.g. unmoving due to balance of the hydraulic fluid25pressure in chamber24bagainst the bias of the resilient element27of the piston22towards the partition21) with respect to the partition21. For example, the piston20can move away from the partition21(e.g. under influence of the mechanical element12or under influence of injected hydraulic fluid into the chamber24a) while the piston22remains stationary (e.g. unmoving due to balance of the hydraulic fluid25pressure in chamber24bagainst the bias of the resilient element27of the piston22towards the partition21) with respect to the partition21. For example, the piston20can move towards the partition21(e.g. under influence of the mechanical element12) while the piston22moves away from (e.g. due to unbalance of the hydraulic fluid25pressure in chamber24bagainst the bias of the resilient element27of the piston22) the partition21. For example, the piston20can move towards the partition21(e.g. under influence of the mechanical element12) while the piston22moves (e.g. due to unbalance of the hydraulic fluid25pressure in chamber24bagainst the bias of the resilient element27of the piston22) towards to the partition21. For example, the piston20can remain stationary with respect to the partition21while the piston22moves towards (e.g. moving due to unbalance of the hydraulic fluid25pressure in chamber24bagainst the bias of the resilient element27of the piston22towards the partition21) the partition21. For example, the piston20can remain stationary with respect to the partition21while the piston22moves away from (e.g. moving due to unbalance of the hydraulic fluid25pressure in chamber24bagainst the bias of the resilient element27of the piston22towards the partition21) the partition21. In many of the above cases, it is recognised that the movement of the piston20can result in either an ingress or egress of hydraulic fluid25with respect to the chamber24abased on how the valves34,38,48are open/closed. In many of the above cases, it is recognised that the movement of the piston22can result in either an ingress or egress of hydraulic fluid25with respect to the chamber24bbased on how the valves34,38,48are open/closed.

While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modification of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments. Further, all of the claims are hereby incorporated by reference into the description of the preferred embodiments.