Variable speed drive with electronic control means

Claim 2

A variable speed unit comprising: a housing defining a fluid reservoir; a shaft at least partially located in the reservoir and comprising first and second shaft sections; a series of radially disposed clutch plates mounted in said reservoir for rotation with said first shaft section; a series of friction discs carried by said second shaft section for rotation therewith, and adapted for selective frictional engagement with said clutch plates; actuating means located in said housing for selectively compressing said plates and said discs; a source of pressurized hydraulic fluid; control circuit means providing an output signal in accordance with a desired rotary motion of said second shaft section; and a hydraulic circuit operatively coupling said source of pressurized hydraulic fluid with said actuating means and including a valve means responsive to said output signal; said hydraulic circuit defining a first hydraulic output circuit via which hydraulic fluid from said source is applied to said actuating means and the pressure thereof is modulated by said valve means in accordance with said output signal for selectively modulating the pressure loading of said plates and discs, whereby said second shaft section is rotated in accordance with said desired rotary motion, said hydraulic circuit also defining a second output circuit via which at least a portion of pressurized hydraulic fluid from said source is discharged onto said series of plates and said series of discs.

Claim 3

The unit as recited in claim 1 further comprising a pulse gear mounted for rotation with one of said shaft sections, and magnetic pick-up means disposed proximate said gear for providing a feedback signal to said control circuit means.

Claim 4

The unit as recited in claim 2 wherein the output signal for said circuit means is adjusted in accordance with said feedback signal.

Claim 5

A variable speed drive of the viscous shear type adapted for selectively driving a driven machine from a constant speed motor, the drive comprising: a housing assembly defining a fluid reservoir; an input shaft rotatably supported by said assembly and drivingly connected to said motor; an output shaft rotatably supported by said assembly and at least partially located in said reservoir; a plurality of clutch plates located in said reservoir and supported for rotation with said input shaft; a series of friction discs carried by said output shaft for rotation therewith; actuating means in said housing selectively positionable for clampingly compressing said clutch plates with said series of friction discs; piston means connected to said actuating means for effecting movement thereof; pressurized hydraulic fluid means acting on one side of said piston means for selectively positioning said actuating means; and control means for controlling the magnitude of pressure of said fluid means applied to said piston means and correspondingly the degree of compression relative to said clutch plates and said series of friction discs, said control means including a control circuit providing a variable output signal in accordance with a preselected output shaft angular speed and relIef valve means responsive to said output signal for modulating the hydraulic pressure applied to said piston means in accordance with said output signal; and a hydraulic fluid path from said relief valve to said clutch plates and said friction discs via which fluid from said pressurized hydraulic fluid means is discharged onto said plates and discs.

Claim 6

A variable speed drive of the viscous shear type adapted for selectively driving a driven machine from a constant speed motor, the drive comprising: a housing assembly defining a fluid reservoir; an input shaft rotatably supported by said assembly and drivingly connected to said motor; an output shaft rotatably supported by said assembly and at least partially located in said reservoir; a plurality of clutch plates located in said reservoir and supported for rotation with said input shaft; a series of friction discs carried by said output shaft for rotation therewith; actuating means in said housing selectively positionable for clampingly compressing said clutch plates with said series of friction discs; piston means connected to said actuating means for effecting movement thereof; pressurized hydraulic fluid means acting on one side of said piston means for selectively positioning said actuating means; and control means for controlling the magnitude of pressure of said fluid means applied to said piston means and correspondingly the degree of compression relative to said clutch plates and said series of friction discs, said control means including a control circuit providing a variable output signal in accordance with a preselected output shaft angular speed and relIef valve means responsive to said output signal for modulating the hydraulic pressure applied to said piston means in accordance with said output signal; and a hydraulic fluid path from said relief valve to said clutch plates and said friction discs via which fluid from said pressurized hydraulic fluid means is discharged onto said plates and discs.

Claim 7

The variable speed drive as recited in claim 4 wherein said assembly includes a plurality of ribs, and wherein said drive further comprises air circulating means for directing air movement across said ribs.

Claim 8

The variable speed drive as recited in claim 5 wherein said air circulating means includes a fan drivingly connected to one of said input and output shafts.

Claim 9

A variable speed drive of the viscous shear type adapted for selectively driving a driven machine from a constant speed motor, the drive comprising: a housing assembly defining a fluid reservoir and including a plurality of ribs; an input shaft rotatably supported by said assembly and drivingly connected to said motor; an output shaft rotatably supported by said assembly and said input shaft, and at least partially located in said reservoir; air circulating means including a fan drivingly connected to one of said input and output shafts for directing air movement across said ribs; a shroud connected to said assembly and at least partially surrounding said fan for directing air movement across said ribs; a plurality of clutch plates located in said reservoir and supported for rotation with said input shaft; a series of friction discs carried by said output shaft for rotation therewith; actuating means operatively supported by said output shaft and positionable for selectively clampingly compressing said clutch plates with said series of friction discs; piston means connected to said actuating means for effecting movement thereof; pressurized hydraulic fluid means acting on one side of said piston means for selectively positioning said actuating means; and means for controlling the magnitude of said fluid means and correspondingly the degree of compression relative to said clutch and said series of friction discs while simultaneously supplying said fluid means to said plates and discs for cooling.

Claim 10

A variable speed drive of the viscous shear type adapted for selectively driving a driven machine from a constant speed motor, the drive comprising: a housing assembly defining a fluid reservoir and including a plurality of ribs; an input shaft rotatably supported by said assembly and drivingly connected to said motor; an output shaft rotatably supported by said assembly and said input shaft, and at least partially located in said reservoir; air circulating means including a fan drivingly connected to one of said input and output shafts for directing air movement across said ribs; a shroud connected to said assembly and at least partially surrounding said fan for directing air movement across said ribs; a plurality of clutch plates located in said reservoir and supported for rotation with said input shaft; a series of friction discs carried by said output shaft for rotation therewith; actuating means operatively supported by said output shaft and positionable for selectively clampingly compressing said clutch plates with said series of friction discs; piston means connected to said actuating means for effecting movement thereof; pressurized hydraulic fluid means acting on one side of said piston means for selectively positioning said actuating means; and means for controlling the magnitude of said fluid means and correspondingly the degree of compression relative to said clutch and said series of friction discs while simultaneously supplying said fluid means to said plates and discs for cooling.

Claim 11

The variable speed drive as recited in claim 7 wherein said pressurized fluid means includes a pump mounted on said shroud and drivingly connected to one of said input and output shafts.

Claim 12

The variable speed drive as recited in claim 8 further comprising a fluid media located in said reservoir, and first fluid conduit means connected to said reservoir and said pump for transferring said fluid media therebetween.

Claim 13

The variable speed drive as recited in claim 9 further comprising second fluid conduit means connected to said pump and said piston means for transferring said fluid media therebetween.

Claim 14

The variable speed drive as recited in claim 10 wherein said control means includes valve means connected between said second conduit means and said reservoir for providing a variable restriction whereby to control the pressure acting on one side of said piston means.

Claim 15

A variable speed drive of the viscous shear type and adapted for selectively driving a driven machine from a constant speed motor, the drive comprising: a housing assembly defining a fluid reservoir; water jacket means formed by said assembly for transferring heat from said drive unit; an input shaft rotatably supported by said assembly and said input shaft, and at least partially located in said reservoir; a plurality of clutch plates located in said reservoir and supported for rotation with said input shaft; a series of friction discs carried by said output shaft for rotation therewith; actuating means operatively supported by said output shaft and positionable for selectively clampingly compressing said clutch plates with said series of friction discs; pistoN means connected to said actuating means for effecting movement thereof; pressurized hydraulic fluid means acting on one side of said piston means for selectively positioning said actuating means; and means for controlling the magnitude of said fluid means and correspondingly the degree of compression relative to said clutch and said series of friction discs while simultaneously supplying said fluid means to said plates and discs for cooling.

Claim 16

A variable speed drive of the viscous shear type and adapted for selectively driving a driven machine from a constant speed motor, the drive comprising: a housing assembly defining a fluid reservoir; water jacket means formed by said assembly for transferring heat from said drive unit; an input shaft rotatably supported by said assembly and said input shaft, and at least partially located in said reservoir; a plurality of clutch plates located in said reservoir and supported for rotation with said input shaft; a series of friction discs carried by said output shaft for rotation therewith; actuating means operatively supported by said output shaft and positionable for selectively clampingly compressing said clutch plates with said series of friction discs; pistoN means connected to said actuating means for effecting movement thereof; pressurized hydraulic fluid means acting on one side of said piston means for selectively positioning said actuating means; and means for controlling the magnitude of said fluid means and correspondingly the degree of compression relative to said clutch and said series of friction discs while simultaneously supplying said fluid means to said plates and discs for cooling.

Claim 17

The variable speed drive as recited in claim 12 which includes a plurality of circumferentially spaced fin means for increasing the surface area therein.