US3724583A — Hydraulic motor and pump system

Claim 1

Independent Claim 500 words

A hydraulic drive system for a wheeled vehicle comprising: a hydraulic pump having a means for varying its effective displacement; means for driving said hydraulic pump; a hydraulic motor for at least one wheel, said motor having means for varying its effective displacement and being driven by said pump; said means for varying the effective displacement of said pump including control means for controlling the effective displacement of said pump in direct proportion to the rate of rotational speed thereof; said means for varying the effective displacement of said motor including control means for controlling the effective displacement of said motor in inverse proportion to the rate of rotational speed thereof, whereby the torque to speed ratio at said driven wheel is greater at lower vehicle speeds than at higher vehicle speeds; each of said variable displacement pump and motor including a piston for controlling the displacement thereof, and each of said pump controlling means and said motor controlling means comprising: a valve having first and second chambers therein; first and second valve elements movably mounted in said first and second chambers respectively; a first opening in said first chamber being in flow communication with a source of fluid; a second opening in said second chamber being in flow communication with the displacement piston of one of said variable displacement pump and variable displacement motor; an intermediate opening between said first and second chambers, said valve elements being in slidable, abutting engagement at said intermediate opening; first and second spaced passages through said first valve element in flow communication with said first chamber opening and extending to said intermediate opening; a third passage in said second valve element in flow communication with said second chamber opening and extending to said intermediate opening; the opening of said third passage at said intermediate opening being positioned between the openings of said first and second passages at said intermediate opening whereby it is normally closed because of said slidable, abutting engagement of said first and second valve elements; means for increasing the pressure at one of said first chamber opening and second chamber opening with respect to the other and for moving one of said first and second passages into alignment with said third passage to effectuate fluid flow between said fluid source and said piston; means for moving said second valve element and correspondingly said third passage out of alignment with one of said first and second passages and in the same direction in which said first valve element was originally moved to thereby again discontinue the flow of fluid between said fluid source and said piston; said valve for said pump being adjusted such that fluid flows from said fluid source to said piston during vehicle deceleration and flows from said piston to said fluid source during vehicle acceleration; said valve for said motor being adjusted such that fluid flows from said piston to said fluid source during vehicle deceleration and from said fluid source to said piston during vehicle acceleration.

Claim 2

Dependent Claim 500 words

A hydraulic drive system for a wheeled vehicle comprising: a hydraulic pump having a means for varying its effective displacement; means for driving said hydraulic pump; a hydraulic motor for at least one wheel, said motor having means for varying its effective displacement and being driven by said pump; said means for varying the effective displacement of said pump including control means for controlling the effective displacement of said pump in direct proportion to the rate of rotational speed thereof; said means for varying the effective displacement of said motor including control means for controlling the effective displacement of said motor in inverse proportion to the rate of rotational speed thereof, whereby the torque to speed ratio at said driven wheel is greater at lower vehicle speeds than at higher vehicle speeds; each of said variable displacement pump and motor including a piston for controlling the displacement thereof, and each of said pump controlling means and said motor controlling means comprising: a valve having first and second chambers therein; first and second valve elements movably mounted in said first and second chambers respectively; a first opening in said first chamber being in flow communication with a source of fluid; a second opening in said second chamber being in flow communication with the displacement piston of one of said variable displacement pump and variable displacement motor; an intermediate opening between said first and second chambers, said valve elements being in slidable, abutting engagement at said intermediate opening; first and second spaced passages through said first valve element in flow communication with said first chamber opening and extending to said intermediate opening; a third passage in said second valve element in flow communication with said second chamber opening and extending to said intermediate opening; the opening of said third passage at said intermediate opening being positioned between the openings of said first and second passages at said intermediate opening whereby it is normally closed because of said slidable, abutting engagement of said first and second valve elements; means for increasing the pressure at one of said first chamber opening and second chamber opening with respect to the other and for moving one of said first and second passages into alignment with said third passage to effectuate fluid flow between said fluid source and said piston; means for moving said second valve element and correspondingly said third passage out of alignment with one of said first and second passages and in the same direction in which said first valve element was originally moved to thereby again discontinue the flow of fluid between said fluid source and said piston; said valve for said pump being adjusted such that fluid flows from said fluid source to said piston during vehicle deceleration and flows from said piston to said fluid source during vehicle acceleration; said valve for said motor being adjusted such that fluid flows from said piston to said fluid source during vehicle deceleration and from said fluid source to said piston during vehicle acceleration.

Claim 3

Dependent Claim 100 words

The system of claim 2 in which said means for moving said second valve element in the same direction in which said first valve element was originally moved comprises said second valve chamber being in fluid flow communication with said second opening at one end of said second valve element, whereby changes in relative pressure at said second opening are gradually transmitted to said one end of said second valve element in said second chamber; bias means being provided at the other end of said second valve element for biasing it towarD one direction of movement within said second chamber.

Claim 4

Dependent Claim 131 words

The system of claim 2 in which said means for moving said first valve element and for effectuating a pressure differential between said first and second chamber openings comprises: governor means for applying a force to said first valve element which is proportional to the rate of rotation of one of said pump and said motor; bias means being operably associated with said governor means for opposing said force applied to said governing means; pump means for said fluid source; bypass valve means associated with said fluid source and controlled by said governor for opening and closing a return line to said fluid source pump whereby the fluid pressure at said first chamber opening of said valve can be increased or decreased depending on the relative position of said bypass valve.

Claim 5

Dependent Claim 458 words

A hydraulic drive system for a wheeled vehicle comprising: a hydraulic pump having a means for varying its effective displacement, means for driving said hydraulic pump; a hydraulic motor for at least one wheel, said motor having means for varying its effective displacement and being driven by said pump; said means for varying the effective displacement of said pump including control means for controlling the effective displacement of said pump in direct proportion to the rate of rotational speed thereof; said means for varying the effective displacement of said motor including control means for controlling the effective displacement of said motor in inverse proportion to the rate of rotational speed thereof, whereby the torque to speed ratio at said driven wheel is greater at lower vehicle speeds than at higher vehicle speeds; a first fluid flow system for driving the front wheels and a second fluid flow system for driving the rear wheels of said vehicle, said first and second fluid flow systems each comprising at least one variable displacement pump and at least one variable displacement motor; means interconnecting said first and second fluid flow systems for equalizing pressure differentials which may arise therebetween during the operation of said vehicle; said means for equalizing pressure comprising a pressure equalizing valve including a first chamber and a spool mounted therein having two end portions, and a central portion around which fluid in said first chamber cannot flow; said spool being mounted for slidable movement in said first chamber; an opening into each end of said first chamber, being in flow communication with one of said two fluid flow systems; means biasing said spool toward a normal position in said first chamber; a second chamber in said pressure equalizing valve; at least one passage between said first and second chambers being positioned at each spool end when said spool is in its normal position, such that said passages are normally blocked by said spool ends; said spool being slidable in said first chamber such that upon increase in pressure in one of said fluid flow systems, said spool shifts away from said opening which is in flow communication with the increased pressure system, toward the other opening in said first chamber such that said passages between said first and second chambers are open; each end of said spool including passages extending therethrough such that when said passages between said first and second chambers are open, fluid can flow from the high pressure end of said first chamber, through said second chamber, back into said first chamber in the space between said spool end and said spool central portion and through said passages in said spool end and through said opening in said first chamber into the lower pressure system.

Claim 6

Dependent Claim 458 words

A hydraulic drive system for a wheeled vehicle comprising: a hydraulic pump having a means for varying its effective displacement, means for driving said hydraulic pump; a hydraulic motor for at least one wheel, said motor having means for varying its effective displacement and being driven by said pump; said means for varying the effective displacement of said pump including control means for controlling the effective displacement of said pump in direct proportion to the rate of rotational speed thereof; said means for varying the effective displacement of said motor including control means for controlling the effective displacement of said motor in inverse proportion to the rate of rotational speed thereof, whereby the torque to speed ratio at said driven wheel is greater at lower vehicle speeds than at higher vehicle speeds; a first fluid flow system for driving the front wheels and a second fluid flow system for driving the rear wheels of said vehicle, said first and second fluid flow systems each comprising at least one variable displacement pump and at least one variable displacement motor; means interconnecting said first and second fluid flow systems for equalizing pressure differentials which may arise therebetween during the operation of said vehicle; said means for equalizing pressure comprising a pressure equalizing valve including a first chamber and a spool mounted therein having two end portions, and a central portion around which fluid in said first chamber cannot flow; said spool being mounted for slidable movement in said first chamber; an opening into each end of said first chamber, being in flow communication with one of said two fluid flow systems; means biasing said spool toward a normal position in said first chamber; a second chamber in said pressure equalizing valve; at least one passage between said first and second chambers being positioned at each spool end when said spool is in its normal position, such that said passages are normally blocked by said spool ends; said spool being slidable in said first chamber such that upon increase in pressure in one of said fluid flow systems, said spool shifts away from said opening which is in flow communication with the increased pressure system, toward the other opening in said first chamber such that said passages between said first and second chambers are open; each end of said spool including passages extending therethrough such that when said passages between said first and second chambers are open, fluid can flow from the high pressure end of said first chamber, through said second chamber, back into said first chamber in the space between said spool end and said spool central portion and through said passages in said spool end and through said opening in said first chamber into the lower pressure system.

Claim 7

Dependent Claim 86 words

The system of claim 4 in which said spool is biased by a spring positioned at each of said ends, said openings into each end of said first chamber comprising a stand pipe extending into said chamber for a distance greater than the length of said spring when it is fully compressed such that a seal is effected by the action of said spool end pressing against the end of saiD stand pipe in the event that one of said two fluid flow systems completely depressurizes.

Claim 8

Dependent Claim 200 words

A hydraulic drive system for a wheeled vehicle comprising: a hydraulic pump having a means for varying its effective displacement; means for driving said hydraulic pump; a hydraulic motor for at least one wheel, said motor having means for varying its effective displacement and being driven by said pump; said means for varying the effective displacement of said pump including control means for controlling the effective displacement of said pump in direct proportion to the rate of rotational speed thereof; said means for varying the effective displacement of said motor including control means for controlling the effective displacement of said motor in inverse proportion to the rate of rotational speed thereof, whereby the torque to speed ratio at said driven wheel is greater at lower vehicle speeds than at higher vehicle speeds; each said variable displacement pump and said variable displacement motor comprising: a vane track having a movable section whereby variable displacement is achieved; a rotor carrying a plurality of vanes mounted for radially slidable movement therein, a counterweight mounted in said rotor for each of said vanes and being operably connected to said vane for offsetting the centrifugal force acting on said vane during rotation of said rotor.

Claim 9

Dependent Claim 200 words

A hydraulic drive system for a wheeled vehicle comprising: a hydraulic pump having a means for varying its effective displacement; means for driving said hydraulic pump; a hydraulic motor for at least one wheel, said motor having means for varying its effective displacement and being driven by said pump; said means for varying the effective displacement of said pump including control means for controlling the effective displacement of said pump in direct proportion to the rate of rotational speed thereof; said means for varying the effective displacement of said motor including control means for controlling the effective displacement of said motor in inverse proportion to the rate of rotational speed thereof, whereby the torque to speed ratio at said driven wheel is greater at lower vehicle speeds than at higher vehicle speeds; each said variable displacement pump and said variable displacement motor comprising: a vane track having a movable section whereby variable displacement is achieved; a rotor carrying a plurality of vanes mounted for radially slidable movement therein, a counterweight mounted in said rotor for each of said vanes and being operably connected to said vane for offsetting the centrifugal force acting on said vane during rotation of said rotor.

Claim 10

Dependent Claim 52 words

The system of claim 6 in which said counterweight and said vane are connected through a pivoted arm; the moment arm of said vane about the pivot of said pivoted arm being slightly greater than the moment arm of said counterweight to held insure continuing contact between said vane and said track.

Claim 11

Dependent Claim 44 words

The system of claim 7 in which said pivoted arm extends into a slot in said vane and fits loosely therein whereby said vane is free to move radially within said rotor while said pivoted arm moves through an arc about its pivot point.

Claim 12

Dependent Claim 45 words

The system of claim 7 in which said counterweight and said vane are connected through a pivoted arm; bias means being operably connected to said arm for biasing said vane to movement radially outwardly whereby continuing contact between said vane and said track are insured.

Claim 13

Dependent Claim 45 words

The system of claim 6 in which said counterweight and said vane are connected through a pivoted arm; bias means being operably connected to said arm for biasing said vane to movement radially outwardly whereby continuing contact between said vane and said track are insured.

Claim 14

Dependent Claim 351 words

A hydraulic drive system for a wheeled vehicle comprising: a hydraulic pump having a means for varying its effective displacement; means for driving said hydraulic pump; a hydraulic motor for at least one wheel, said motor having means for varying its effective displacement and being driven by said pump; said means for varying the effective displacement of said pump including control means for controlling the effective displacement of said pump in direct proportion to the rate of rotational speed thereof; said means for varying the effective displacement of said motor including control means for controlling the effective displacement of said motor in inverse proportion to the rate of rotational speed thereof, whereby the torque to speed ratio at said driven wheel is greater at lower vehicle speeds than at higher vehicle speeds; a return reservoir and a bypass line to said reservoir are provided whereby the fluid pumped by said pump can be returned through said bypass line to said reservoir rather than being circulated to said motor; a bypass valve on said bypass line for opening and closing said bypass line; a vacuum line to a vacuum source; first and second valve means positioned in series on said vacuum line whereby said vacuum line is open only when both said first and second valve means are open; means for opening said first valve when said engine accelerator is released and for closing said first valve when said engine accelerator is depressed; means for opening said second valve below a preselected engine speed and for clOsing said second valve above said preselected engine speed; a control piston; means biasing said control piston to normally close said bypass valve; said control piston being connected to said vacuum line whereby the opening of said first and second valves causes a vacuum to act on said control piston, against said biasing means, and thereby open said bypass valve and thereby open said bypass line; said first valve acting to open said vacuum line to the atmosphere when closed, thereby allowing said biasing means to close said bypass valve and thereby close said bypass line.

Claim 15

Dependent Claim 351 words

A hydraulic drive system for a wheeled vehicle comprising: a hydraulic pump having a means for varying its effective displacement; means for driving said hydraulic pump; a hydraulic motor for at least one wheel, said motor having means for varying its effective displacement and being driven by said pump; said means for varying the effective displacement of said pump including control means for controlling the effective displacement of said pump in direct proportion to the rate of rotational speed thereof; said means for varying the effective displacement of said motor including control means for controlling the effective displacement of said motor in inverse proportion to the rate of rotational speed thereof, whereby the torque to speed ratio at said driven wheel is greater at lower vehicle speeds than at higher vehicle speeds; a return reservoir and a bypass line to said reservoir are provided whereby the fluid pumped by said pump can be returned through said bypass line to said reservoir rather than being circulated to said motor; a bypass valve on said bypass line for opening and closing said bypass line; a vacuum line to a vacuum source; first and second valve means positioned in series on said vacuum line whereby said vacuum line is open only when both said first and second valve means are open; means for opening said first valve when said engine accelerator is released and for closing said first valve when said engine accelerator is depressed; means for opening said second valve below a preselected engine speed and for clOsing said second valve above said preselected engine speed; a control piston; means biasing said control piston to normally close said bypass valve; said control piston being connected to said vacuum line whereby the opening of said first and second valves causes a vacuum to act on said control piston, against said biasing means, and thereby open said bypass valve and thereby open said bypass line; said first valve acting to open said vacuum line to the atmosphere when closed, thereby allowing said biasing means to close said bypass valve and thereby close said bypass line.

Claim 16

Dependent Claim 335 words

A hydraulic drive system for a wheeled vehicle comprising: a first fluid flow system for driving the front wheels and a second fluid flow system for driving the rear wheels of said vehicle, said first and second fluid flow systems each comprising at least one variable displacement pump and at least one variable displacement motor; means interconnecting said first and second fluid flow systems for equalizing pressure differentials which may arise therebetween during the operation of said vehicle; said means for equalizing pressure comprising a pressure equalizing valve including a first chamber and a spool mounted therein having two end portions, and a central portion around which fluid in said first chamber cannot flow; said spool being mounted for slidable movement in said first chamber; an opening into each end of said first chamber, being in flow communication with one of said two fluid flow systems; means biasing said spool towards a normal position in said first chamber; a second chamber in said pressure equalizing valve; at least one passage between said first and second chambers being positioned at each spool end when said spool is in its normal position, such that said passages are normally blocked by said spool ends; said spool being slidable in said first chamber such that upon increase in pressure in one of said fluid flow systems, said spool shifts away from said opening which is in flow communication with the increased pressure system, towards the other opening in said first chamber such that said passages between said first and second chambers are open; each end of said spool including passages extending therethrough such that when said passages between said first and second chambers are open, fluid can flow from the high pressure end of said first chamber, through said second chamber, back into said first chamber in the space between said spool end and said spool central portion and through said passages in said spool end and through said opening in said first chamber into the lower pressure system.

Claim 17

Dependent Claim 335 words

A hydraulic drive system for a wheeled vehicle comprising: a first fluid flow system for driving the front wheels and a second fluid flow system for driving the rear wheels of said vehicle, said first and second fluid flow systems each comprising at least one variable displacement pump and at least one variable displacement motor; means interconnecting said first and second fluid flow systems for equalizing pressure differentials which may arise therebetween during the operation of said vehicle; said means for equalizing pressure comprising a pressure equalizing valve including a first chamber and a spool mounted therein having two end portions, and a central portion around which fluid in said first chamber cannot flow; said spool being mounted for slidable movement in said first chamber; an opening into each end of said first chamber, being in flow communication with one of said two fluid flow systems; means biasing said spool towards a normal position in said first chamber; a second chamber in said pressure equalizing valve; at least one passage between said first and second chambers being positioned at each spool end when said spool is in its normal position, such that said passages are normally blocked by said spool ends; said spool being slidable in said first chamber such that upon increase in pressure in one of said fluid flow systems, said spool shifts away from said opening which is in flow communication with the increased pressure system, towards the other opening in said first chamber such that said passages between said first and second chambers are open; each end of said spool including passages extending therethrough such that when said passages between said first and second chambers are open, fluid can flow from the high pressure end of said first chamber, through said second chamber, back into said first chamber in the space between said spool end and said spool central portion and through said passages in said spool end and through said opening in said first chamber into the lower pressure system.

Claim 18

Dependent Claim 86 words

The system of claim 12 in which said spool is biased by a spring positioned at each of said ends, said openings into each end of said first chamber comprising a stand pipe extending into said chamber for a distance greater than the length of said spring when it is fully compressed such that a seal is effected by the action of said spool end pressing against the end of said stand pipe in the event that one of said two fluid flow systems completely depressurizes.

Claim 19

Dependent Claim 238 words

A hydraulic system for wheeled vehicles comprising: a pump; a motor for at least one wheel being driven by said pump; a return reservoir and a bypass line to said reservoir whereby the fluid pumped by said pump can be returned through said bypass line to said reservoir rather than being circulated to said motor; a bypass valve on said bypass line for opening and closing said bypass line; a vacuum line to a vacuum source; first and second valve means positioned in series on said vacuum line whereby said vacuum line is open only when both said first and second valve means are open; means for opening said first valve when said engine accelerator is released and for closing said first valve when said engine accelerator is depressed; means for opening said second valve below a preselected engine speed and for closing said second valve above said preselected engine speed; a control piston; means biasing said control piston to normally close said bypass valve; said control piston being connected to said vacuum line whereby the opening of said first and second valves causes a vacuum to act on said control piston, against said biasing means, and thereby open said bypass valve and thereby open said bypass line; said first valve acting to open said vacuum line to the atmosphere when closed, thereby allowing said biasing means to close said bypass valve and thereby close said bypass line.

Claim 20

Dependent Claim 238 words

A hydraulic system for wheeled vehicles comprising: a pump; a motor for at least one wheel being driven by said pump; a return reservoir and a bypass line to said reservoir whereby the fluid pumped by said pump can be returned through said bypass line to said reservoir rather than being circulated to said motor; a bypass valve on said bypass line for opening and closing said bypass line; a vacuum line to a vacuum source; first and second valve means positioned in series on said vacuum line whereby said vacuum line is open only when both said first and second valve means are open; means for opening said first valve when said engine accelerator is released and for closing said first valve when said engine accelerator is depressed; means for opening said second valve below a preselected engine speed and for closing said second valve above said preselected engine speed; a control piston; means biasing said control piston to normally close said bypass valve; said control piston being connected to said vacuum line whereby the opening of said first and second valves causes a vacuum to act on said control piston, against said biasing means, and thereby open said bypass valve and thereby open said bypass line; said first valve acting to open said vacuum line to the atmosphere when closed, thereby allowing said biasing means to close said bypass valve and thereby close said bypass line.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-04-02	1976-10-02	1977-04-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-04-02	1980-10-02	1981-04-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-04-02	1984-10-02	1985-04-03	$7700.00	Window Closed / Lapsed

Hydraulic motor and pump system

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