US1259090A

US1259090A - Control for hydraulic transmissions.

Info

Publication number: US1259090A
Application number: US3392015A
Authority: US
Inventors: Walter Ferris; William E Magie
Original assignee: Individual
Current assignee: Individual
Priority date: 1915-06-14
Filing date: 1915-06-14
Publication date: 1918-03-12
Anticipated expiration: 1935-03-12

Description

W. FE'R'RIS & W. E. MAGIE.

coNTRoL FoR HYDRAULIC TANsMlssIoNs.

APPLICATION FILED )UNE I4, I9I5.

3,59,9@ www Mar. 12, 1918.

`TEE STATES PATENT @FFEO WALTER EERRIs, 0E MILWAUKEE, WIsooNsIN, AND WILLIAM E. MAGIE, or

EvANsvILLE, INDIANA. y

GDNTROL FOR HYDRAULIC TRANSMISSIONS.

naaaoao.

To all whom t may concern:

Be it known that we, WALTER FERRIS and WILLIAM E. MAGIE, citizens of the United States, residing, respectively, at Milwaukee, in the county of Milwaukee and State of Wisconsin. and at Evansville, in the county of Vanderburg and State vofflndiana, have invented a certain new and useful Improvement in Controls for Hydraulic Transmissions, of which the following is a specificat1on.

Our invention relates to improvements in control means for hydraulic transmission and has for one object to provide a means for automatically controlling the transmission itself and the prime mover which operates it. 1For the purpose of convenience we have selected an ordinary gas engine as the prime mover and the transmission we have illustrated as a pump wherein the stroke may be varied for the purpose of changing the out-put per revolution. The liquid pumped by this pump operates a motor` which motor in turn carries the load or overcomes the resistance. The power requirement may be met by various reciprocal combinations of pump speed with-pump displacement. -For instance, if the pumps maximum capacity is 100 cubic inches displacement per revolution and 1000 revolutions per minute and 500 pounds per square inch pressure, the pump will deliver about 125 H. P. when all these Variables are maxima. Suppose now that the resistance consists of a torque in the motor shaft of 4000 inch lbs. at 500 revolutions per minute yor about 82 H. P. This requires that 500 (revolutions per minute of motor) -l- 100 (cubic inch displacement of motor pistons er revolution) equals 50,000 cubic inches of oil be handled by the pump in one minute; also that this oil be pumped into the motor at 250 lbs. pressureas the required torque of 4000 inch lbs. is one-half of the maximum torque; maximum equals 100 cubic inches 500 lbs. per sq. in. pressure divided by 6.2832 equals A8,000 inch lbs.

Now the pump can handle 50,000 cubic inches of oil per minute at 250 lbs. pressure vin an infinite number of ways and still meet the requirementthat the motorbe drivenv at Specification of Letters Patent.

- 500 revolutions per minute. Thus the pump Full stroke ..-and 5400 revolutions per minute las L d H l H LL :1U H and LI H i 196 u and u u n e, "Zand 1000 f and 1 250 ,au v and 1666 itself to give the torque required by the resistance. This, however, will not be an economical method because during light torques and small speeds of motor both prlme mover and pump will be running at high speeds and small torque, while both of them would have a better efliciency at lower speeds and higher torques. ln the above case, it will be better to have the pump running at full stroke and 500 revolutions per minute, thus slowing the gasolene engine down to V500 revolutions. Even at this speed it only gets an indicator card of one-half of full load area, as the torque delivered by the motor is one-half full load torque. The transmission also will work at higher eicienoy with full stroke and slower speed.

The object of the mutual control, therefore, is to obtain a higher eiiciency for the combined prime mover and transmission pump at small power deliveries by reducing their speeds as permitting them to deliver a high enough torque to run at good eiiciency despite the reduced load.

This mutual control may be worked out in a great many forms. ln the accompanying drawing we show a form in which the operator selects the position of the lever or other control means to ix the pump displacement,

Patented Mar. 12, i918.

Application led June 14, 1915. Serial No. 33,920.

-closely connected one to the other.

pump housing contains the variable dis-- the secondary automatic devices controlling the speed and torque of the prime mover corresponding to the work done by the pump and hydraulic motor. The invention is illustrated diagrammatically in the accompanying drawing, wherein is shown a side elevation.

A is a prime mover which we have here shown for convenience as any suitable wellknown type of gasy or other internal combustion engine. A1 is a centrifugal governor driven by any suitable mechanism as shown from the engine crank or drive shaft A2. A3 is a carbureter adapted to supply a combustible fluid to the yair drawn in through the intake pipe A4 controlled by the throttle valve A5. The carbureter discharges the combustible mixture thus formed to the engine and theengine then operates in the usual manner being controlled in its speed and power out-put by the throttle valve.

B is a pump housing. B1 a motor housling charge pump not here illustrated adapted to be driven at all times in unison with the prime mover by the drive shaft A2 which extends from the prime mover to the pump. The ump is connected to the motor by any .suita le hydraulic transmission pipes not here shown. B2 is a motor shaft driven by and adapted to be driven at all times with the motor. It carries a pinion B8 in mesh with a gear B4 which gear'in turn is connected to the resistance or load which it is" proposed to move.

C is a pump control lever. When it is in the neutral position the pump while still rotating with the prime moverdoes not have any discharge and does not therefore do any useful work. Therefore, while the lever is in the neutral position the motor is at rest. When the lever is moved to the right the pump forces the fluid in one direction through the system and when moved to the left the fluid is discharged in the opposite direction and thus causes the motor toturn in one direction or the other as the case may be. e The farther the lever is moved from neutral toward its extreme position the greater the iow of the pump and therefore the greater the amount of Huid displaced and the higher the speed of the motor. C1 `is an arm projecting from the control lever C carrying a cam member C2. C3 is a link slidable in the :bearing C4 on a housing B having a roller C in engagement with the cam member C2 and pivotally supporting at its free end a floating lever C". This floating lever .is con- `nected by a link C1 to a bell crank lever Cs controlled by the governor A1.

Intermediate the two -ends of the floating lever C is a lug D. This lug D has pivotally connected thereto one end of a pressure control floating lever D1, the pivot pass- D7 tends to move the piston and rod to the right and hydraulic pressure from the transmission system with which the cylinder D6 is connected by the pipe D8 tends to resist this movement of the piston and forces .it to the left.

It will be evident that while we have shown in our drawings an operative device, still many changes might be made both in size, shape and arrangement of parts without departing from the spirit of ourvinvention, and we wish, therefore, that the drawings be regarded as in a sense diagrammatic.

The pressure cylinder and piston and cooperating parts form what is in effect a hydraulic governor which operates responsive to the pressure in the pump and circulating system.

The use and operation of our invention is as follows In the neutral position of lever, as shown, the pump has no displacement, there is therefore no pressure in the system and the cylinder and theprime mover is operating only at friction load. The centrifugal governor is set for a suicient throttle opening to maintain a low engine speed, say half speed, at friction load. `As the hand lever is moved in either direction, giving a displacement to the pump, the cam surface, link and oating levers give additional opening to the throttle, enabling the engine to meet the increased load which is to be anticipated as a result of the increased displacement. Should the torque encountered by the hydraulic motor also increase, the pressure in the pump will increase proportionately. Should this occur, the hydraulic cylinder D6 and co-acting parts also give corresponding additionalopening to the throttle independently of the opening resulting from increasing the displacement of the pump. Both "increments of' throttle opening are suicient operator, and the higher the pressure in the pump cylinders which results from the resistance encountered by the hydraulic motor. T he centrifugal governor attached to the prime mover checks at a proper predetermined point the increases of speed due to the additional throttle opening accompanying the increases of displacement and pressure..

Thus the prime mover will always tend to work at the maximum practicable torque and the lowest practicable speed for a required power output.

In this arrangement the judgment of the operator is relied upon to select a displacement within the power capacity of the enine. Other automatic devices may readily e introduced to protect the engine from overload.

Thus there are three controls all of them operating upon the throttle. lf the governor speeds up with nothing else moving it tends to close the throttle. Tf the rotation of the prime mover increases the pump will work harder and the pressure will rise. This will thrust the piston out and open the throttle.. Tf the hand lever is moved to increase the stroke of the pump this will open the throttle. ny two of these movements may occur simultaneouslyor any three of them and it is the summation of the two or three movements as the case may be which controls the speed and torque of the engine.

Tt will be understood that the power out-.

put of the prime mover is controlled by manipulation of the throttle valve and that this manipulation or operation of the throttle valve is a 'summation of the control movements resultant upon the action of the inertia governor driven by the prime mover, the hydraulic governor operated by the pressure on the pump and the control lever which adjusts the displacement of the pump irrespective of its rotational speed. Thus velocity changes in the prime mover and pressure changes in the pump system and the manual manipulation of the displacement of the pump all three in unison affect the throttle and thus the power output of the prime mover, Tf any two of these different forces are inactive the other force will directly control the power output. Tf any two or more of these forces are simultaneously active the power output control will be the resultant of the simultaneous action of these separate correlated controlling movements.

This arrangement is shown applied to the throttle of a combustion motor. Tt might be equally well shown applied to a control memher for any type of prime mover, for instance, the throttle valve of a steam engine, the rheostat control of an electric motor or any other suitable arrangement of prime mover and control.

The pump that we have shown is a pump having a rotating part and that rotating part is the controlling and driving part and, therefore, the speed of the pump may be and we have preferably expressed it in terms of rotation, though it is perfectly obvious that it might be expressed in other terms, as for instance, terms of reciprocation or in terms of complete cycles of operation. lt is possible toconceive of a pump in which there is no rotating part but there must be some kind of a rotating connection and any reciprocatory movement of the pump and the prime mover whether mechanically translated into rotary movement or not can be expressed in terms of rotation. Therefore, we do not wish our invention to be considered as limited to a pump or a prime mover which rotates as there are, of course, reciprocating parts as we have shown and there might be reciprocating parts without rotary parts, though the preferred forms is as we have indicated. f

Generally speaking, our device is intended to be used with three elementsfof control, viz: the centrifugal governor, vthe hydraulic cylinder governor and the hand lever. Tt is, of course, perfectly obvious that any one of the three may be rendered inoperative or dispensed with without impairing the util- 'ity of the'invention. For instance, if the operation of the hydraulic governor should be arrested, the hand lever and the centrifugal governor only will be in operation whereupon the mechanism will act as follows:

As the operator increases the displacement of the pump by moving the hand lever, the throttle opening of the prime mover is automatically increased to take care of anticipated larger load. This larger load will, of course, comprise elements of larger displacement and higher pressure in the pump. rThe latter' element is now not included in the automatic control and the result will be that the centrifugal governor on the engine will effect the necessary throttle opening by lowering the speed of the engine until it is able to take care of the increased torque. Tf the engine runs too slowly or threatens to shut down, the operat-or merely moves the hand lever reducing the displacement, permitting the engine to run at higher speed and less torque.

Similarly the control elements might comprise only the centrifugal governor and a pressure cylinder in connection with a pump whose displacement is not varied. The operator would then vary the pressure in the pump by increasing` or decreasing the resistance of the hydraulic motor.

We claim l. A prime mover, a pump driven thereby, a motor driven by the pump, means for varying the displacement of the pump independent of its rate of rotation andy means responsive to the rotational speed of the prime mover, the pressure inthe pump and the displacement varying means for controlling the power, output of the prime mover. 2. A prime mover, a pump driven thereby, a motor driven by the pump, means for varying the displacement of the pump independent of its rate of rotation, means for controlling the power output of the prime mover and separate actuating members for said means responsive to the speed of rotation of the prime mover, the pressure inthe pump and the displacement varying means.

3. A prime mover, a pump driven thereby, a motor driven bythe pump, means for varying the displacement of the pump independent of its rate of rotation, means for controlling the power\output of the prime mover and separate actuating members for said means responsive to the speed of rotation of the prime mover, the pressure in the pump and the displacement varying means, said operating members being interconnected and mutually interdependent in theirtotal effect upon the power control. j

4. A prime mover, a pump driven thereby, a motor driven by the pump, means'for varyin the displacement of the pump Yindepen ent of its rate of rotation, an inertia governor driven by the prime mover, a hydraulic governor operated by the pressure in the pump, means for controlling the f power output of the prime mover, separate control.

operative connections between the power control and the two governors and the displacement control. 5

5. A prime mover, a pump driven thereby, a motor driven bythe pump, means for varying the displacement of the pump independent of its rate of rotation, an inertia governor driven by the prime mover, a hydraulic governor operated by the pressure in the pump, means for controlling the power output of the prime mover, separate operative connections between the power control and the two governors and the displacement control, said operating members being interconnected and mutually interdependent in their total effect upon the power 6. A prime mpver, a pump driven thereby, a-motor driven bythe pump, means for varying the displacement of the pump independent of its rate of rotation and means simultaneously responsive tothe rotational speed of!q the prime mover, the pressure in the pump and the displacement varying means for v'controlling the power output of the prime mover.

7. The combination with a variable speedA prime mover, a variable displacement pump driven thereby, a motor driven by the pump of a mutual control acting upon the prime mover and pump, to simultaneously vary the `displacement of the pump and the power .output of the prime mover.

8.-,'Tl1e combination with a variable speed means comprising an operative leve.1 di-` rectly connected to the pump and apower output'controlmeans for the prime mover and a connection between it and the lever.

9. A prlme mover and means for control-A ling its speed, a governor responsive to the speed of the'prime mover, a Vvariable displacement pump, operating means for varying the displacement of the pump and coacting means-connected together for operating in unison the operating means, the governor and the speed control. l

10. A prime mover, means for controlling lthe speed thereof, a governoi` responsive to the speed thereof, a variable displacement pump, operating means to vary the displacement thereof, a hydraulic governor responsive to pressure within the pump and coacting means connecting together the operating means, the hydraulic governor, the prime mover driven governor and the speed Control means.

11. A prime mover, having a speed governor, a pump driven thereby, a motor driven by the pump, means for controlling the power output of the prime mover, means for selectively adjusting the pump for a predetermined displacement, a hydraulic governor responsive to the pressure in the pump and connections between the power controlling means, and the governor and the adjusting means;

12. A prime mover, a pump driven thereby, a motor driven by the pump, means for controlling the power output of the primi?l mover, means for selectively adjusting the pump for apredetermined displacement, a hydraulic -governor operated by the pressure in the pump, an inertia governor driven by the prime mover and connections between the power controlling means, the adjusting means, the hydraulic governor and the inertia governor. v

13. A by, a motor driven by the pump, means for controlling the power output of the prime mover, means for selectively adjusting the pump for a predetermined displacement, a hydraulic governor responsive to the pressure in the pump and connections between the power controlling means, ernor and the adjusting means, said connections being interdependent in their action upon the power control means.

14. A prime mover, apump driven thereby, a motor driven by the pump, means for 'controlling the power output of the prime mover, means ,for selectively adjusting the pump for apredetermined displacement, a

and a motor driven by the A prime mover, a pump driven therecontrolling ertia governor, said connections being interdependent in their action upon the powerV control means.

15. A prime mover, a pump driven thereby, a motor` driven by the pump, means for controlling the power output of the prime mover, meansfor varying the displacement of the pump independent of its rate of rotation, an inertia governor driven by the prime mover, a floating lever, a connection between it and the power control and connections between the floating lever and the governor and the pump displacement varying means.

16. A prime mover, a pump driven thereby, a motor driven by the pump, means for controlling the power output of the prime mover, means for v-arying the displacement of the pump independent of its rate of rotation, a hydraulic governor responsive to the pressure in the pump, a floating lever, a connection between it and the power control and connections between the ioating lever and the governor andthe pump displacement-varying means.

17. A prime mover, a pump driven there- IIlOeI', 11163115 means for of the pump independent of its rate of rot'a- A tion, a hydraulic governor operating in response to the pressure in the pump and an inertia governor driven by the prime mover, a floating lever, a connection between it and the power control means and separate connections between the ioating lever and the two governors and the pump output varying' means.

18. A prime mover, a variable dlsplacement pump driven thereby, means for varydisplacement, a motor driven and'means for controlling the power output of Ithe prime mover simultaneously responsive to the rotational speed of the prime mover and to the displacement varying means of the pump.

19. The combination with a prime mover anda power transmission mechanism driven thereby of means for controlling the power output of the prime mover and separate operating means therefor responsive one of them to the speed of the prime mover, the other to conditions within the transmission mechanism. p 4

' Signed at South Milwaukee, Wisconsin, this 10th day of J une, 1915.,

WALTER FERRIS. y WlLLlAM E.

ing the pump by the pump,

Witnesses:

W. J. RYAN, E. K/Swlcon'r.