Viscous clutch with minimum output speed.

(54) Title: CLUTCH WITH VISCOUS COUPLING WITH MINIMUM OUTPUT SPEED. (54) Title: VISCOUS CLUTCH WITH MINIMUM OUTPUT SPEED.

(57) Summary

A viscous coupling clutch (30) includes a rotor (36), a casing member (38), a working chamber (50) located between the casing member and the rotor, a reservoir (48) for maintaining viscous fluid which is configured to rotate with the rotor, a return hole (64) in fluid communication between the working chamber and the reservoir, a first passage (66) from the reservoir to the working chamber, a second passage (82) from the tank to the working chamber, and a valve (40). The second passage is separate from the first passage, and can extend substantially radially through the rotor. The valve is configured to selectively regulate the flow of the viscous fluid through the first passage, and the second passage is unobstructed, such that the viscous fluid can pass from the reservoir to the working chamber, regardless of the operational state of the valve. The viscous fluid present in the working chamber rotationally couples the rotor and the housing element.

(57) Abstract

A viscous clutch ineludes a rotor, a housing member, a working chamber located between the housing member and the rotor, a reservoir to hold viscous fluid that is configured to rotate with the rotor, a return bore in fluid communication between the working chamber and the reservoir, a first passage from the reservoir to the working chamber, a second passage from the reservoir to the working chamber, and a valve. The second passage is spaced from the first passage, and can extend substantially radially through the rotor. The valve is configured to selectively regulate flow of the viscous fluid through the first passage, and the second passage is unobstructed such that the viscous fluid can pass from the reservoir to the working chamber regardless of the operational State of the valve. Viscous fluid present in the working chamber rotationally couples the rotor and the housing member.

PATENT TITLE No. 360331

Headlines):

Home:

Denomination:

Classification:

Inventors):

NORTON, INC.

2565 Walnut Street, Rosevüle, Minnesota, 55113, USA

CLUTCH WITH VISCOUS COUPLING WITH MINIMUM OUTPUT SPEED.

CIP:

CPC:

^35/02

35/021

F16D35 / 02 F16D

DEREK SAVELA; SCOTT MILLER

REQUEST

Number:

MX / a / 2015/010901

International Presentation Date:

February 2014

PRIORITY

Number:

^61,782229

<img file="MX360331B_D0001.tif" />

usfrial.

ogables, counted to

Country:

^L

Validity: Vet Expiration Date: Issue Date

The patent of refere

Pursuant to e as of the date of p;

Who subscribes and presents you (Official Journal of the Fed

01/25/2006, 06/05 / 200S, 06/01/201 and 12 · sections i and 111 of the R,

07/28/2004 and 09/07/2007); articles 1 »,

Industrial Property (DOF 12/27/1999 powers in the Deputy Directors General!

Departmental Coordinators and other subordinates' 07/29/2004, 08/04/2004 and 09/13/2007).

Industrial Property Law 1999, 01/26/2004, 06/16/2005, β 1®, 3 'section V subsection a), 4 ° on 07/01/2002, 07/15/2004, of the Mexican Institute of the

3 ° and 5 * Clause a) of the Agreement that delegates

Regional, Divisional Deputy Directors, (DQF 12/15/1999, amended on 02/04/2000,

This letter is signed with an advanced electronic signature (IF'IEL), based on joint articles 7 BIS 2 of the Industrial Property Law; 3rd of its Regulation, and 1 section III, 2 section V, 26 BIS and 26 TER of the Agreement to be established) The guidelines for the use of the Electronic Payment and Services Portal (PASE) of the Mexican Institute of Industrial Property! , in the procedures indicated.

THE DIVISIONAL DIRECTOR OF PATENTS

<img file="MX360331B_D0002.tif" />

NAHANNY CANAL REYES

Original string:

NAHANNY MARISOL CANAL REYES | 0000100000Q403252793 | Tributary Administration Service | 1695 | jMX / 2019 / 3959jMX / a / 2015/010901 | PCT Patent Title | 1220 | RRGO: | Pág (s) | 46 + axtlmS3yWJpxSsyPHYC +

Digital stamp;

vnN9qpr3lO2OCUJAo7CVYbwRsfKDQqMVneW8vfCL0f0ySTwzniLuz7YFdHwPuLuSNadFbrFgncusdQ4qNz1FcheAZy

ZK8SfgysY7: EcOHtnAPxavbqReK: NgfyhooT: Dx / xrEAfJHIJv1EdlGDEO¡jzGDpSr5vhel8YYvSF2UmSTeXRzacBI // 3

3IDzp5jaPRIbtsgtlslknEwgS6NVdP9 + WMOXRjpW3zSyvncZC4HNM1kDbK7QbVdyfsnUQ2S8zmTYpAcor5VAYkJyQ / MI

9wE / vVi3jEjZ8opdkqwNEcyHNnvCtnQifHF9OXcHlcY8kYXzD1DI42XTFDbKEW4vVAKi6vw ==

Arenal No. 550, Floor 1, Puebio Santa Mana Tepepan, Xochímíico, 1: 6020,

Mexico City.

(55) 53340700 www.gob..rnx / ¡rnpi

MX / 2019/3859

CLUTCH WITH VISCOUS COUPLING WITH \

MINIMUM OUTPUT

FIELD OF THE INVENTION

The present invention relates, in general, to clutches and, more particularly, to viscous coupling clutches.

BACKGROUND OF THE INVENTION

Viscous clutches are used in a wide variety of automotive fan drive applications, among other uses. These clutches typically employ relatively thick silicone oil (generally called shear fluid or viscous fluid) for selective torque transmission between two rotating components. It is possible to engage or disengage the clutch by selectively allowing oil to enter and exit a clutch working area located between the inlet and outlet elements (for example, between an inlet rotor and an outlet housing). A valve is used to control the flow of oil in the working area between the inlet and the outlet. Recent clutch designs have been employed that allow oil to be stored in the rotational inlet portion of the clutch while the clutch is disengaged, to maintain the kinetic energy available to the oil, and to enable rapid clutch engagement of the condition. disengaged. This also allows the clutch to have a very low output speed (for example, fan speed) while the valve is positioned to obstruct oil flow in the work area. It has also become common for the clutch to be electrically controlled. This has been done to increase the clutch controllability, and also to make the clutch capable of responding to multiple cooling needs in a vehicle. Some of the possible cooling needs are the coolant temperature, the inlet air temperature, the air conditioning pressure, and the oil temperature.

However, electrical control of a clutch with ------------ ------ requires extensive effort to develop a desired control algorithm that governs the response of the clutch to operating parameters. A separate control algorithm may be required for each application, even when the basic clutch geometry remains the same.

Therefore, it is desired to provide an alternative viscous coupling clutch.

BRIEF DESCRIPTION OF THE INVENTION

A viscous coupling clutch Includes a rotor, a casing element, a working chamber located between the casing element and the rotor, a reservoir for storing a viscous fluid that is configured to rotate with the rotor, a communication return port of fluid between the working chamber and the reservoir, a first passage from the reservoir to the working chamber, a second passage from the reservoir to the working chamber, and a valve. The second passage is separate from the first passage, and can extend substantially radially through the rotor. The valve is configured to selectively regulate the flow of the viscous fluid through the first passage, and the second passage is unobstructed, such that the viscous fluid can pass from the reservoir to the working chamber, regardless of the operational state of the valve. The viscous fluid present in the working chamber rotationally couples the rotor and the housing element.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a cross-sectional view of one embodiment of a clutch in accordance with the present invention.

Figure 2 is a cross-sectional perspective view of a portion of the clutch.

Figure 3 is an enlarged cross-sectional view of a portion of the clutch.

Although the figures identified above set forth embodiments of the present disclosure, other embodiments are also contemplated, __________________ the disclosure. In all cases, the present disclosure presents the invention by way of representation and not of limitation. It should be understood that numerous other modifications and embodiments may be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and the applications and embodiments of the present invention may include features and components that are not specifically shown in the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a viscous coupling clutch assembly, and associated method of use, which is suitable for use as a fan clutch in automotive applications. In general, the clutch (or actuator) may include a bypass hole (or passage) and a valve hole (or passage) each extending between a reservoir and a working chamber. A viscous (or shear) fluid can be introduced into the working chamber to create a viscous shear coupling to transmit torque between an inlet and an outlet, such as to transmit torque from a motor to a cooling fan. A return port can provide a return passage for the viscous fluid, from the working chamber to the reservoir. The bypass port can remain open and unobstructed during all operating conditions such that viscous fluid can continuously pass through the bypass port from the reservoir to the working chamber to maintain the viscous coupling between the inlet and the Clutch output at (or above) a minimum threshold at all times. A valve can be positioned to selectively cover and uncover the valve orifice, to selectively introduce additional viscous fluid into the working chamber to increase the viscous coupling between the clutch inlet and outlet to a relative maximum. One of the benefits of the present invention is the ability to provide a relatively simple clutch coupling that allows multiple speed operation without the need to provide application specific control algorithms to match the clutch to operating parameters, such as cooling demand, motor speed, etc. This allows a single clutch configuration to be easily used in a variety of applications without the need for custom modification. Another advantage of the present invention is the ability to provide multi-speed clutch operation without the need for a pneumatic or hydraulic drive system as is commonly required with (non-viscous) friction clutches.

FIG. 1 is a cross-sectional view of one embodiment of a clutch 30, including a bearing clamp (or axle bracket) 32, a pulley 34, a rotor 36, a two-part housing 38, a valve assembly 40, an electromagnetic coil 42, a first bearing assembly 44, a second bearing assembly 46, a reservoir 48, a working chamber 50, and an outlet structure (eg, fan) 54. The clutch 30 defines an axis rotation A. In addition, a controller 80 may be provided. The clutch 30 may resemble a clutch that is disclosed in US Patent Application Publication No. 2012/0279820, "Legally Transferred Clutch with Integrated Viscous Coupling," which is incorporated in the present specification by reference in its entirety. However, it should be noted that the illustrated embodiment is shown by way of example only and not by way of limitation, and in other embodiments other clutch configurations are possible.

Bearing clamp 32 can be a stationary (i.e. non-rotating) component that is attached to a mounting location, such as an engine block in a vehicle's engine compartment. It should be understood that although it has been described as being stationary, the bearing clamp 32 can be installed inside a moving vehicle, and the term stationary is used herein in connection with the mounting location. In the illustrated embodiment, the bearing clamp 32 includes an axially extending shaft portion 32-1 and a generally radially extending flange portion 32-2. In alternative embodiments, the clutch 30 could be provided with a live shaft in place of the stationary bearing clamp 32. The clamp ___ ~ - cr ~~ is structurally functional, and in some embodiments may also be magnetically functional.

The pulley (or sheave) 34 is rotatably supported on the shaft portion 32-1 of the bearing clamp 32 in the illustrated embodiment, and is configured to accept input of the torque of a belt (not shown). In the illustrated embodiment, the pulley 34 is positioned adjacent the flange portion 32-2 of the bearing clamp 32. Furthermore, in the illustrated embodiment, the pulley 34 surrounds the shaft portion 32-1 of the bearing clamp 32 and is rotatably mounted on the shaft portion 32-1 by the first bearing assembly 44, which can be aligned axially with a coupling portion of belt 34-1 of pulley 34. A size (i.e. diameter) of the coupling portion of the belt 34-1 can be selected to help provide a desired input rotational speed to the clutch 30, as will be understood by persons of skill in the art. A lateral portion 34-2 of the pulley 34 extends generally and axially forward from the coupling portion of the belt 34-1.

Rotor 36 is attached to side portion 34-2 of pulley 34, and therefore accepts torque input to clutch 30 each time input torque is provided. In one embodiment, a threaded connection is provided between rotor 36 and side portion 34-2 of pulley 34. As shown in Figure 1, rotor 36 is generally disk or ring shaped, and is positioned to surround shaft portion 32-1 of bearing clamp 32, which generally extends radially outward. Rotor 36 may include a series of concentric annular ribs on its two front and rear sides near an outer diameter portion in a conventional arrangement. One or more fluid openings or passages may be formed through rotor 36 to allow shear fluid to pass between the rear sides of the front-facing rotor and 36. Suitable radially extending channels or grooves may be formed in the faces rear or front rotor 36 to provide space for valve mounting 40.

In the illustrated embodiment, the reservoir 48 is directly attached to the rotor 36, and the torque input to the clutch 30 rotates the reservoir

Reservoir 48 may contain a supply of a shear fluid (eg, silicone oil) for use by clutch 30. Because rotor 36 is part of an inlet subassembly with pulley 34, rotor 36 rotates always whenever there is a rotation input to pulley 34. Rotation of rotor 36 in turn maintains shear fluid in reservoir 48 under pressure, allowing shear fluid to be maintained at a relatively high level of kinetic energy to help facilitate rapid engagement of clutch 30. As will be explained later, the ability to maintain a high level of kinetic energy in the fluid decreases the clutch reaction time.

The housing 38 in the illustrated embodiment includes a base 38-1 and a cover 382, ​​and forms an output or torque supply portion of the clutch 30. In the illustrated embodiment, the cover 38-2 provides the mounting for the frame outlet 54 (eg, a fan) to the clutch 30. The cooling fins can be provided on the outside of the housing 38 to help dissipate heat into the ambient air. In the illustrated embodiment, housing 38 is rotatably supported on shaft portion 32-1 of bearing clamp 32, and surrounds shaft portion 32-1. The second bearing assembly 46 can mount the cover 38-2 rotatably on the shaft portion 32-1 of the bearing clamp 32, with the cover 38-2 in turn supporting the base 38-1 and the outlet 54. Base portion 38-1 and cover portion 38-2 can be secured together with suitable fasteners.

Working chamber 50 (synonymously called a working area) is defined between rotor 36 and housing 38. The presence of shear fluid in working chamber 50 creates a fluid friction coupling between rotor 36 and housing 38 to engage clutch 30 and transmit torque between input and output components. An instantaneous percentage of torque transmission can vary as a function of the amount of shear fluid in working chamber 50. In general, shear fluid is supplied to working chamber 50 from reservoir 48 along one or both of the first and second fluid circuits (described below), and is returned to reservoir 48 from chamber working 50 through return path

<img file="MX360331B_D0003.tif" />

ΜΡΙ

OF THE Ρ

64. One or more suitable pumping structures can be used in the working chamber 50 to pump the dynamic shear fluid out of the working chamber 50 through the passageway of the working chamber 50. return 64.

Valve assembly 40 can be connected to and carried by rotor 36. In one embodiment, valve assembly 40 is configured as described in published PCT application WO 2012/024497, entitled Viscous Coupling Clutch Valve Assembly, legally transferred, which is incorporated herein by reference in its entirety. Valve assembly 40 is used to selectively cover and uncover a first opening (or passage or outlet hole) 66 from reservoir 48. In some embodiments, opening 66 can be defined in a hole plate 68 that forms a wall of the deposit 48. Opening 66 is a valve port or orifice which, when uncovered (i.e. open), allows shear fluid to flow from reservoir 48 into working chamber 50 along the first fluid passage (which may traverse passages, grooves, channels, etc. in rotor 36). Valve assembly 40 can be pushed into the open position, for example, using a spring pushing force. Valve assembly 40 may include armature 70 located near axis A of clutch 30 and in close proximity to electromagnetic coil 42. As explained below, by energizing electromagnetic coil 42 armature 70 can be moved such that that valve assembly 40 covers first opening 66. It should be understood that almost any known type of electromagnetically actuated valve assembly can be used in alternative embodiments.

Electromagnetic coil 42 may include a wound coil of insulated high-temperature copper wire placed in a cup (eg, a steel cup) that is used to direct flow in armature area 70 along a flow circuit. Coil 42 may be rotatably integral relative to shaft portion 32-1. In the illustrated embodiment, coil 42 surrounds and is supported by shaft portion 32-1 of bearing clamp 32, and can be mounted directly on shaft portion 32-1. Proper wiring for coil 42 can be routed internally through bearing clamp 32 such that no fixing or mounting brackets of coil u are required.

clutch 30 and the output structure (eg fan) 54. The coil 42 need not be mounted on any of the bearings, since the shaft part 32-1 is fixed in rotation. On the other hand, in the illustrated embodiment, coil 42 is positioned within housing 38 and in reservoir 48, that is, axially aligned with reservoir 48 and positioned radially inward of an outer diameter of reservoir 48. When power is applied to coil 42 during operation, armature 70 is attracted to coil 42 due to the resulting magnetic field.

Figure 2 is a cross-sectional perspective view of a portion of the clutch 30, and Figure 3 is an enlarged cross-sectional view of a part of the clutch 30. Figures 2 and 3 are sectional views taken in an angular position different around axis A of figure 1.

As shown in Figures 2 and 3, a second or additional opening (or passage or exit of the hole) 82 from the tank 48 to the working chamber 50 is provided at a location separate from the first opening 66, the hole plate 68 and valve assembly 40. The second opening 82 in the illustrated embodiment provides a bypass hole that is angularly spaced from the first opening 66 about axis A (ie, in a circumferential direction) by an angle Θ, which is greater than zero. In one embodiment, angle Θ is approximately 90 °. The second opening 82 is unobstructed, and can remain unobstructed, regardless of the operational state of valve assembly 40. There is no valve assembly that regulates the flow of fluid through the second opening 82 in the illustrated embodiment. The second opening 82 defines an inlet 82-1 from the tank 48, a central body part 82-2 and an outlet 82-3 of the working chamber 50. In the illustrated embodiment, inlet 82-1 of second opening 82 is located radially outward from valve assembly 40 in an outer diameter portion of reservoir 48, and outlet 82-3 is located in an outer diameter portion of both the rotor 36 and the working chamber 50. The central body part 82-2, which connects the inlet and the outlet 82-1 82-3, can be arranged substantially radially. In additional embodiments, the second opening 82 can provide additional outlets that release shear fluid in working chamber 50 to different or multiple radial locations.

A diameter of the second opening 82 can be selected to provide measurement of the shear fluid flow at a desired speed, to provide higher or lower output speed when valve assembly 40 is in the off position and blocking the fluid flow through first opening 66. Measurement can be provided anywhere along second opening 82.

Because reservoir 48 rotates with rotor 36, and rotates whenever there is torque input to clutch 30, a relatively constant and consistent flow of shear liquid through second opening 82 can be provided to the working chamber. 50 due to the kinetic energy imparted to the shear fluid in the illustrated embodiment. The kinetic energy provided to the shear fluid in the rotation reservoir 48 can also help to maintain the flow relatively constant despite the continuous pumping of the shear fluid back into the reservoir 48 from the working chamber 50 through the return passage 64 The substantially radial orientation of the second opening 82 can help to provide the relatively rapid supply of shear fluid from reservoir 48 to working chamber 50. Furthermore, because the shear fluid is stored in a single tank, common 48 in the illustrated embodiment, the shear fluid is easily and equally available in both the first and second openings 66 and 82, without having to divide the shear fluid between the various reservoir chambers in a way that could potentially create unbalanced fluid levels or require additional components such as a manifold that would undesirably increase the complexity of the clutch.

In operation, the clutch 30 provides multi-speed operation. The clutch 30 can provide a viscous coupling between an inlet and an outlet at all times, with the output speed selectively controlled between a relatively low engagement mode and a full engagement mode. Such control can be provided through the provision of the first and second fluid passages of the single tank, I ate, ... - work 50. The first fluid passage through first opening 66 can be selectively opened and closed using valve assembly 40, while the second fluid passage through second opening 82 can remain open and unobstructed at all times, regardless of the operation of any valve assembly. Shear fluid can pass through second opening 82 into working chamber 50. In this way the clutch 30 can operate at a lower output speed (at all times) instead of being fully disengaged. Basically, the viscous coupling clutch 30 can act as a two-speed device. In an automotive cooling fan application, the lowest speed can be used for most general cooling requirements and the fully coupled mode can be used for large cooling requirements. However, the clutch 30 can still be a purely viscous device, without the need for any of the components of a friction clutch that would undesirably add weight. On the other hand, a low speed operational mode can be provided when the torque input is provided by the clutch 30, without reliance on initial actuation of valve assembly 40 to achieve low speed engagement mode.

Selective control of electromagnetic coil 42 and, in turn, valve assembly 40 can be governed by controller 80, which can be dedicated circuitry for clutch 30 or, alternatively, can be integrated with other circuitry. In one embodiment, the electromagnetic coil 42 can be brute or binary powered on / off by the controller 80, such that the valve assembly 40 tends to remain in any one of a fully open position (the default position ) or a fully closed position when coil 42 is selectively energized. In another embodiment, coil 42 can be energized using pulse width modulated (PWM) signals from an electronic motor controller (not shown). PWM signals allow a dynamically variable average volume of shear fluid to flow out of reservoir 48 through first opening 66 Cl i \ iwiyw viszi | ~ / i lililí fluid passage. Depending on the width of the pulse (i.e. duration) and the frequency of the PWM signals, valve assembly 40 can variably adjust the amount of shear fluid that allows it to exit reservoir 48 through opening 66. to the working chamber 50 over time.

For some applications, it may be preferable to provide only a binary on / off control. In general, users in transition from on-off clutches (for example, single speed friction clutches) to viscous clutch clutches need a control loop algorithm that determines the required output speed (for example, fan speed) and controls the fully variable speed viscous clutch accordingly. The present invention allows a fully variable speed viscous coupling clutch to be used with a simple binary on / off control strategy. While binarlo-controlled sayings lack full speed control, it is sufficient for many users without the resources to develop the required control algorithm while still giving those users more functionality than a standard on-off clutch.

Description of possible achievements

The following are non-exclusive descriptions of possible embodiments of the present invention.

A viscous coupling clutch may include a rotor; a housing element; a working chamber located between the housing element and the rotor, in which a viscous fluid present in the working chamber rotationally couples the rotor and the housing element; a reservoir for storing the viscous fluid, the reservoir being configured to rotate with the rotor; a return port in fluid communication between the working chamber and the reservoir, to allow the viscous fluid to return from the working chamber to the reservoir; a first conduit from the tank to the working chamber; a second passage from the reservoir to the working chamber, in which the second passage is separated from the first passage, and ----- ¿___ passage extends substantially radially through the rotor; and a valve, in which the valve is configured to selectively regulate the flow of the viscous fluid through the first passage, in which the second passage is obstructed such that the viscous fluid can pass from the reservoir to the working chamber , regardless of the operating state of the valve.

The clutch of the preceding paragraph may optionally additionally and / or alternatively include any one or more of the following additional features, configurations and / or components:

the tank can be directly attached to the rotor;

an electromagnetic coil configured to selectively actuate the valve; and a controller, in which the controller is configured to govern the operation of the electromagnetic coil, such that the valve is acclinable in a binary on / off mode;

the second passage defines an inlet from the tank and an outlet to the working chamber, the inlet being located radially out of the valve; and / or the second passage defines an inlet from the tank and an outlet to the working chamber, the inlet being located in a portion of the tank's outer diameter.

A procedure for operating a viscous coupling clutch may include rotating a reservoir with a torque input to the viscous coupling clutch; the continuous supply of a viscous fluid from the reservoir to a working chamber through a bypass orifice; actuating a valve to selectively supply the viscous fluid from the reservoir to the working chamber through a valve port; and the return of the viscous fluid from the working chamber to the tank.

The procedure of the previous paragraph may optionally include, additionally and / or alternatively, any one or more of the following additional stages, configurations and / or characteristics:

Viscous fluid can be returned from the working chamber to the tank continuously:

the bypass orifice can supply the viscous fluid to a place spaced from the valve orifice; and / or the bypass orifice can introduce the viscous fluid to an outside diameter portion of the working chamber.

A viscous coupling clutch may include a rotor configured to accept torque input; a housing element; a working chamber located between the housing element and the rotor, in which a viscous fluid present in the working chamber rotationally couples the rotor and the housing element to transmit the torque; a reservoir for storing at least a part of the viscous fluid; a return port in fluid communication between the working chamber and the reservoir, to allow the viscous fluid to return from the working chamber to the reservoir; a first conduit from the tank to the working chamber; a second passage from the tank to the working chamber, the second passage defining an entrance from the deposit and an exit to the working chamber, the entrance being located in a portion of the tank's outer diameter, and the entrance of the second passage being separated from the first passage; and a valve, in which the valve is configured to selectively regulate the flow of the viscous fluid through the first passage, in which the second passage is obstructed such that the viscous fluid can pass from the reservoir to the working chamber , regardless of the operational status of the valve assembly.

The clutch of the preceding paragraph may optionally additionally and / or alternatively include any one or more of the following additional features, configurations and / or components:

the reservoir may be configured to rotate with the rotor; the tank can be directly attached to the rotor;

an electromagnetic coil configured to selectively actuate the valve; and a controller, in which the controller is configured to govern the operation of the electromagnetic coil, such that the valve is operable in a binary on / off mode;

the second passage defines an entrance from the tank and an exit to the working chamber, the entrance being radially outwards d &lt;___________ the second passage defines an entrance from the deposit and an exit to the working chamber, the entrance being located in a portion of the tank outer diameter; the outlet may be located on an outside diameter of the rotor; and / or the second passage can extend substantially radially through the rotor.

In view of the present disclosure, those of skill in the art will appreciate that the present invention provides numerous advantages and benefits over the prior art.

Any relative terms or degree terms used herein, as substantially, essentially, general, and the like, must be interpreted in accordance with and without prejudice to the applicable definitions or limits expressly set forth herein. In all cases, any of the relative terms or degree terms used in this document should be broadly interpreted to encompass any relevant described embodiment, as well as such ranges or variations as would be understood by a person skilled in the art in view of the present disclosure, such as to cover ordinary manufacturing tolerance variations, incidental alignment variations, alignment or shape variations induced by thermal, rotational, or vibrational operating conditions, and the like.

Although the present invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes in form and detail can be made without departing from the spirit and scope of the invention. For example, in other embodiments.