GB2236364A - Automatic transmission comprising planetary gearing and braking pumps - Google Patents
Automatic transmission comprising planetary gearing and braking pumps Download PDFInfo
- Publication number
- GB2236364A GB2236364A GB8918724A GB8918724A GB2236364A GB 2236364 A GB2236364 A GB 2236364A GB 8918724 A GB8918724 A GB 8918724A GB 8918724 A GB8918724 A GB 8918724A GB 2236364 A GB2236364 A GB 2236364A
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- Prior art keywords
- oil path
- braking
- gear
- control valve
- communicated
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H3/00—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
- F16H3/44—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion using gears having orbital motion
- F16H3/72—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion using gears having orbital motion with a secondary drive, e.g. regulating motor, in order to vary speed continuously
- F16H3/721—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion using gears having orbital motion with a secondary drive, e.g. regulating motor, in order to vary speed continuously with an energy dissipating device, e.g. regulating brake or fluid throttle, in order to vary speed continuously
- F16H3/722—Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion using gears having orbital motion with a secondary drive, e.g. regulating motor, in order to vary speed continuously with an energy dissipating device, e.g. regulating brake or fluid throttle, in order to vary speed continuously with a fluid throttle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Structure Of Transmissions (AREA)
- Control Of Transmission Device (AREA)
Abstract
An automatic transmission, includes two planetary gears 10 and 20, two braking pumps 30 and 40, at least one flow control valve and an oil path system provided therebetween for obtaining a continuously variable transmission (CVT). Each ring gear 16 and 26 of the planetary gears 10 and 20 is connected to each rotor shaft 32 and 42 of the two braking pumps 30 and 40, respectively. A sensing means, preferably a centrifugal pump, 50 is provided for sensing a rotation speed of a rear propeller shaft 4 and to output various amounts of pressurised working fluid in response to the rotation speed of the rear propeller shaft 4. The first flow control valve is provided on the oil path system and is controlled by the pressurised working fluid to be closed to various extents so as to reduce the flow within the oil path system. The rotation speeds of each braking pump 30 and 40 together with each ring gear 16 and 26 are also reduced, under extreme conditions the pumps 30 and 40 even stop. Reverse may be provided by engaging a positive claw brake to stop the planet carrier (18). <IMAGE>
Description
METHOD AND APPARATUS FOR PROVIDING AN AUTOMATIC
TRANSMISSION
The present invention relates to a method and an
apparatus for providing an automatic transmission, and
especially to an apparatus comprising at least one planetary gear, -at least one braking pump, at least
one flow control valve and an oil path system provided
therebetween to obtain a continuously variable
transmission (CVT).
Conventionally, the rotation speeds of oil pumps
used for automatic transmission increase in proportion
to the increase of the rotation speed of the rear
propeller shaft. As. is a widely known fact, the oil
pumps consume a portion of energy. In addition, the
mechanical parts of the oil pumps are easily damaged and abraded. Furthermore, the fuel consumption rate of
a car with an automatic transmission is higher than a
car wi-th a manual transmission.
The present invention provides an apparatus having
specially-construc'ted -planetary gears with a special
transmission relationship to resolve the disadvantages
existing in an automatic transmission.
A feature of the present invention is to provide a
method for providing an automatic transmission to
obtain a continuously variable transmission.
Another feature of the present invention is to provide an apparatus having at least one planetary gear for an automatic transmission.
A further feature of the present invention is to provide oil pumps having low rotation speeds to brake the braking gear of at least one planetary gear to obtain the required transmission power.
A further feature of the present invention is to provide durable oil pumps in an apparatus for a continuously variable transmission, wherein the rotation speeds of the oil pumps decrease as the rotation speed of the rear propeller shaft increases, such that under extreme conditions, the oil pumps stop.
A A further feature of the present invention is to provide an apparatus for an automatic transmission which has a lower fuel consumption rate than conventional automatic transmissions.
A further feature of the present invention is to provide a centrifugal pump to sense the rotation speed of a rear propeller shaft and at least one flow control valve is provided to control the rotation speeds of the oil pumps to brake the braking gear of at least one planetary gear in order to obtain a gear reduction ratio for continuously variable transmission.
These and additional objects, if not set forth specifically herein, will be readily apparent to those skilled in the art from the detailed description provided hereinbelow, with appropriate reference to the accompanying drawings.
In the drawings:
Fig. 1 is a cross-sectional view of an embodiment of an apparatus for an automatic transmission in accordance with the present invention;
Fig. 2A is a' schematic view of an oil system of the embodiment of Fig. 1 according to the present invention, wherein the arrows show the path of the working fluid when a shifting lever is at a neutral position;
Fig. 2B is a schematic view of the oil system of
Fig. 2A, wherein the arrows show the path of the working fluid when the shifting lever is at a forwarding position under an engine idling condition;
Fig. 2C is a schematic view of the oil system of
Fig. 2A, wherein the arrows show the path of the working fluid when the'shifting lever is at a forwarding position and the accelerator is pressed;;
Fig. 2D is a-schematic view of the oil system of
Fig. 2A, wherein the arrows show the path of the working fluid when the shifting lever is t a reversing position under engine idling condition;
Fig. 2E is a schematic view of the oil system of
Fig. 2A, wherein the arrows show the path of the working fluid when the shifting lever is at a reversing position and the accelerator is pressed;
Fig. 2F is a schematic view of the oil system of
Fig. 2A, wherein the arrows show the path of the working fluid during engine braking;
Fig. 3 is a cross-sectional view of a flow control valve according to the present invention;
Fig. 4 is a cross-sectional view of a flow control valve provided for engine idling;
Fig. 5 is a cross-sectional view of a manual flow control valve;;
Fig. 6 is a cross-sectional view of a splitdirectional flow control valve according to the present invention;
Fig. 7 is a cross-sect-ional view of a braking valve and an annular ratchet according to the present invention.
As generally known for a planetary gear, if neither the sun gear, the planet carrier nor the ring gear of a planetary gear are fixed, there will always be. free rotation' within the planetary gear and no gear reduction ratio for transmission can be obtained.
Further to the disadvantages of conventional automatic transmissions, the present invention provides a method and an apparatus for an automatic transmission.
In the case of the sun gear, the planet carrier and the ring gear of a planetary gear of the present invention, the gear receiving the transmission of external power is called a driving gear, the gear being braked resulting in a reduction in the rotation speed thereof is called a braking gear, the remaining one is called a driven gear.
Each braking gear of at least one planetary gear of the present invention is connected to each rotor shaft of at least one braking pump. The present invention further utilises a sensing means to sense a rotation speed of a rear propeller shaft and to output various amounts of pressurized working fluid in response to the rotation speed of the rear propeller shaft. A first flow control valve provided on an oil path system is controlled by the pressurised working fluid to be closed to various extents so as to reduce the flow within the oil path system. The rotation speed of at least one braking pump together with each braking gear is also reduced, under extreme conditions the pumps stop. The planetary gear obtains a reaction force therebetween and obtains a desired torque for transmission. Accordingly, a continuously variable transmission is obtained.
Accordingly, the method for providing an automatic transmission in accordance with the present invention comprises the steps of:
(a) sensing a rotation speed of a rear propeller shaft by means of a sensing means and outputting an amount of pressurised working fluid in response to the rotation speed;
(b) closing at 'least one flow control valve to a certain eantent due to the working fluid;
(c) reducing a flow of an oil path system which comprises the flow control valve(s) to a certain extent to reduce the rotation speed of, or to stop, at least one' braking pump;
(d) braking at least one planetary gear to a certain extent by a corresponding number of braking gears thereof; and
(e) obtaining a- gear reduction ratio in response to a reactive force obtained from the planetary gear(s) due to the braking of the braking gear(s).
The apparatus for an automatic transmission in accordance with the present invention comprises a first planetary gear and a second planetary gear, a first braking pump and a second braking pump, a sensing means, an oil path system and a first flow control va-lve provided on said oil path system. Each of the first and second planetary gears has a sun gear, a planet carrier and a ring gear which are respectively accommodated to function as either a driving gear, a driven gear or a braking gear within the first planetary gear and the second planetary gear. A driven gear in the second planetary, gear relates to a corresponding driving gear in the first planetary gear.
A driving gear in the second planetary gear relates to a corresponding driven gear in the first planetary gear. A braking gear in the second planetary gear relates to a corresponding braking gear in the first planetary gear.
The driving gear of the first planetary gear is mounted on an engine crankshaft and the driven gear of the second planetary gear is mounted on a rear propeller shaft. A rotor shaft of the first braking pump is connected to the braking gear of the first planetary gear. A rotor shaft of the second braking pump is connected to the second planetary gear. Both the first braking pump and the second braking pump are communicated to the oil path system and are controlled by the sensing means.
The sensing means - is mounted on the rear propeller shaft for sensing the rotation speed of the rear propeller shaft and outputs an amount of pressurised working fluid in response to the rotation speed -of the rear propeller shaft to close the first flow control valve so as to brake the first and the second braking pumps via the oil path system. The braking gears of the first and the second planetary gears are braked to a certain extent by the first and the second braking pumps, respectively. The driven gears of the first and the second planetary gears obtain a reactive force due to the braking of the braking gear and obtain a gear reduction ratio for transmission. Accordingly, a continuously variable transmission is obtained.
Referring to Fig. 1, an embodiment according to the present invention i-s shown. Figs. 2A to-2F show an oil path system of the embodiment. In the first planetary -gear 10, the sun gear 12 functions as a driving gear, the planet carrier 28 functions as a driven gear, the ring gear 16 functions as a braking gear. In -the second planetary gear 20, the sun gear 22 functions as a driven gear, the planet carrier 28 functions as a driving gear, the ring gear 26 functions as'a braking gear.
Each planet pinion 14 of the first planetary gear 10 shares a planet. pinion shaft 18 and the planet carrier 28 with ;each planet pinion 24 of the second planetary gear 20. The sun gear 12 of the first planetary gear 10 is mounted on an engine crankshaft 3.
The ring gear 16 of the first planetary gear 10 is connected to a rotor shaft 32 of the first braking pump 30 via a first ring gear carrier 34. The ring gear 26 of the second planetary gear 20 is connected to a rotor shaft 42 of the second braking pump 40 via a second ring gear carrier 44. The sun gear 22 of the second planetary gear 20 is mounted on the rear propeller shaft 4. A centrifugal oil pump 50 is provided on the rear propeller shaft 4 for sensing the rotation speed of the rear propeller shaft 4 and functions as the sensing means.
Please refer to Figs. 2A to 2F.- A first end of a first oil path 401 is communicated to an outlet of the first braking pump 30. A first end of a second oil path 402 is communicated to a second end of the first oil path 401. A first end of a third oil path 403 is communicated to a second end of the second oil path 402. A second end of the third oil path 403 is communicated to an inlet of the second braking pump 40.
A first end of a fourth oil path 404 is communicated to an outlet of the second- braking pump 40. A first end of a fifth oil path 405 is communicated to a second end of the fourth oil path 404. A first end of a sixth oil path 406 is communicated to a second end of the fifth oil path 405. A second end of the sixth oil path 406 is communicated to an inlet of the first braking pump 30.
A first end of a seventh oil path 407 is communicated to the second end of the fourth oil path 404. A first end of an eighth oil path 408 is communicated to a second end of the seventh oil path 407. A first end of a ninth oil path 409 is communicated to a second end of the eighth oil path 408. A second end of the ninth oil path 409 is communicated to an oil tank 100. A first end of a tenth oil path 410 is communicated to the first end of the third oil path 403. A second end of the tenth oil path 410 is communicated to the oil tank 100.
Referring- to Fig. 3, a first flow control valve 510 is provided on the eighth oil path 408.. The first flow control valve 510 is communicated to the centrifugal oil pump 50 at one end thereof. While forwarding, when the accelerator is pressed to a certain extent, pump 30 is stopped, the speed of the car is controlled by pup 40. The oil from, pump 40 flows through oil paths 404, 407 and 408, then passing through the -first flow control valve 510 and oil paths 408 and 409 and enters the oil tank 100. Finally, the oil circles back-from the oil tank,106' to pump 40 via oil paths 410 and.403.
When the centrifugal oil pump 50 outputs pressurised oil 65 acting on a piston head 512 to overcome two springs 514 in response to the rotation speed of the rear propeller shaft 4, a gate 516 is linked via a link 518 to move downwards to partially close the eighth oil path 408. The flow from pump 40 passing through the eighth oil path 408 and circling back to pump 40 is thus reduced, thereby the rotation speeds of pump 40 and the ring gear 26 are also reduced. Accordingly, the second planetary gear 20 obtains a reaction force therebetween and obtains the desired gear reduction ratio for transmission.
As the rotation speed of the rear propeller shaft 4 increases, the pressurised oil makes the gate 516 further move downwards, the flow within the eighth oil path 408 is further reduced and the ring gear 26 is further braked so as to obtain a lower gear. reduction ratio. When the gate 5i6 completely closes the eighth oil path 408, the ring gear 26 is completely braked and the lowest gear reduction ratio is obtained. If the rotation speed of the rear propeller shaft 4 decrees, the pressurised oil can not overcome the. force of the springs 514 and the gate 516 is moved upwards due to the spring force and the gear reduction ratio is increased. Therefore, the present invention provides a continuously variable transmission.
A relief valve 510' is provided on a subpipe 408' communicated to the eighth oil path 408 at. two ends -thereof in order to reduce the pressure of overpressurised oil as a conventional pressure relief valve. Furthermore, the relief valve 510' provides the functions of automatically reducing the gear reduction ratio and absorbing impacts and shocks when the car is on a rugged road. Furthermore, a first check valve 130 is provided on the ninth oil path 409 such that the oil in the ninth oil path 409 is only flowable from the first end to the second end thereof. Similarly, a second check valve 140 is provided on the tenth oil path 410 such that the oil in the tenth oil path 410 is only flowable from the second end to the first end thereof.
As shown in Fig. 5, a manually operable second flow control valve 620 for-reversing is provided on the second oil path 402. The second flow control valve 520 is manuaLly opened via a link 522 to move a gate 524 thereof when the shifting lever is at a reversing position. The second flow control valve 520 is manually closed via the link 522 when the shifting lever is not at the reversing position,
A first end of an eleventh oil path 411 is communicated to the~second end of the first oil path 401. A first end of a twelfth oil path 412 is communicated to the first end of the sixth oil path 406. A first end and a second end of a thirteenth oil path 413 are respectively communicated to a second end of the eleventh oil path 411 and a second end of the twelfth oil path 412.A fourteenth oil path 414 is communicated to the eleventh oil path 411 and the twelfth oil path 412 at two ends thereof.
A third flow control valve 530 is provided on the fourteenth oil path 414. The third flow control valve 530 is opened when the shifting lever is at a neutral position. The third flow control valve 530 is closed when the shifting lever is not at the neutral position.
The third flow control valve 530 has the same construction as valve 520 as shown in Fig. - 5.
A relief valve 530' is provided on a subpipe 414' communicated to the fourteenth oil path 414 at two ends thereof for reducing the pressure of over-pressurised oil. Furthermore, the relief valve 530' provides the functions of automatically reducing the gear reduction ratio and absorbing impacts and shocks when the car is on a rugged road.
Referring to Fig. 4, a fourth flow control valve 540 is provided on the thirteenth oil path 413. The fourth flow control valve 540 is connected to a throttle (not shown of an engine via a hollow pipe 544 nd provides the function of sensing the rotation speed of idling. When the accelerator is pressed, the degree of a vacuum in a vacuum drum 546 increases proportional to the increase of the rotation speed of the engine. Various degrees of vacuums are generated and a bellows portion 543 of the vacuum drum 546 is depressed upwardly to link up a link 545 so as to overcome a spring 548. A gate 542 of the fourth flow control valve 540 is activated to partially close the
thirteenth oil path 413. When the accelerator is pressed to a pre-determined extent, gate 542 completely closes the thirteenth oil path 413.When the accelerator is released and the engine is under the idling condition, the vacuum-generated by the vacuum drum 546 is insufficient to overcome the spring 548 and the bellows portion 543 and the gate 542 is moved to its original position.
In order to obtain an instant response when the accelerator is pressed such- as for a manual transmission, the fourth flow control valve 540 is designed such that when the engine is at a lower idling rotation speed, gate 542 of valve 540 is completely open. The vacuum drum 546 is unable ,to overcome the spring 548, the braking pumps and braking gears are therefore not braked. When the engine is at a higher sidling rotation speed, if the braking pedal is not pressed, the vacuum drum overcomes the springs and the gate 542 of valve 540 is partially closed and the braking gears and braking pumps are partially braked.
Therefore, the car coasts as a conventional automatic transmission when the braking pedal is not pressed.
When the braking pedal is pressed or the car is going up a slope, the engine is forced to operate under the lower idling rotation speed and the car does not coast.
Within a few seconds of the accelerator being pressed, valve 540 is closed and a gear reduction ratio for starting of about 16 : 1 down to about 4 : 1 or 3 : 1 is obtained.
A third check valve 150 is provided on the twelfth oil path 412 between an intersection of oil path 413 and oil path 412 and an intersection of oil path 414 and oil path 412 so as to prevent the oil flowing from the first end of the oil path 412 to the second end of the oil path 412. Furthermore, when the car moves at a speed below 20- Kmh, if, the driver does not operate the accelerator, the third check valve 150 automatically stops pump 30 completely In addition, at whatever speed the car is moving, if the engine suddenly stops igniting, check valve 15Q makes the engine keep functioning to obtain an effect rf inertia starting.
A fifth flow control valve 550 (also see Fig. 3) for overdrive is provided on a fifteenth oil path 415 which is communicated to the eighth oil path 408 at two ends thereof. The fifth flow control 'valve 550 is communicated to the centrifugal oil pump 50 at one end thereof and functions as the first flow control valve 510. The fifth flow control valve 550 starts to function after the car reaches a pre-set overdrive speed. Before overdrive speed occurs, the control valve 550 does not close.
A relief valve 550' is provided on a subpipe 415' communicated to the fifteenth oil path 415 at two ends thereof for reducing the pressure of over-pressurised oil.
The present invention further comprises a sixth flow control valve 560 (also see Fig. 5) for economical starting. The sixth flow control valve 560 is provided on a sixteenth oil path 416 communicated to the eighth oil path 408 at two ends thereof. When economical starting is desired, valve 560 is closed to reduce the amount of oil flowing back to pump 40. A relief valve 560' is provided on a subpipe 416' which is communicated to the sixteenth oil path 416 at two ends thereof for- reducing the pressure of over-pressurised oil.
A seventh-flow control valve 570 (also see Fig. 5) for lowering'the gear reduction ratio under extreme conditions is provided on a seventeenth oil path 417 which is communicated to the eighth oil path 408 at two ends thereof. The seventh flow control valve 5i0 is manually opened when a lowering of the gear reduction ratio is needed under extreme conditions. When a lowering of the gear reduction ratio is needed, such as when overtaking another car, when the car is heavily loaded and is going up a slope or when the car encounters a strong wind and it is hard to accelerate, the 'seventh flow control valve 570 is manually opened to allow additional oil flows via the seventeenth oil path 417 in order to accelerate pump 40. The torque for transmission is increased since the braking extent of the ring gear 26 is reduced.
A fourth check valve 180 is provided on oil path 403 between the first end of oil path 403 and pump 40 such that the oil is only flowable from the first end of oil path 403 to pump 40. Furthermore, when the car is moving and the accelerator is not depressed, the fourth check valve 180 provides an effect of automatically stopping pump 40.
The present invention further comprises a securing oil pump 60 for engine braking. The securing pump 60 is mounted on the rear propeller shaft 4 via a rotor shaft 62 thereof. A first end of an eighteenth oil path 418 is communicated to a first end of the securing oil pump 60. A second end of the eighteenth oil path 418 is communicated to a first side of a split-directional flow control valve 200. A first end of a ninteenth' oil path 419 is communicated to a second side of the splitdirectional flow control valve 200. A second end of the ninteenth oil path 419 is communicated to the second end of the second oil path 402. A first end of a twentieth oil path 420 is communicated to a second end of the securing oil pump 60. A first end of a twentyfirst oil path 421 is communicated to a second end of the twentieth oil path 420.A second end of the twentyfirst oil path 421 is communicated to the second end of the seventh oil path 407.
A first end of a twenty-second oil path 422 is communicated to the second side of the splitdirectional flow control valve 200. A second end of the twenty-second oil path 422 is communicated to the second end of the twentieth oil path 420. A twentythird oil path 423 is communicated to the twenty-second oil path 422 at two ends thereof.
An eighth flow control valve 580 (also see Fig. 5} is provided on the twenty-third oil path 423. The eighth flow control valve 580 is opened when the shifting lever is at the neutral position or the reversing position. The eighth flow control valve 580 is closed when the shifting lever is neither at the neutral position nor at the reversing position. When the car has no power and it is needed to push the car in a reverse direction, the eighth flow control valve is manually opened.
A fifth check valve 170 is provided on the twentysecond oil path 422 between the two ends of the twentythird oil path 423. The flow within the twenty-second oil path 422 is restrained so that the working fluid is only flowable from the first end of the twenty-second oil path 422 to the second end of the twenty-second oil path 422. Furthermore, when the car is at rest on a slope before ascending while the engine is under idling condition (the shifting lever is at the forwarding position), the fifth check valve 170 provides a braking effect to prevent the car sliding down the slope.
The split-directional flow control valve 200 (see
Fig. 6) is manually operable and is arranged so that the total amount of flow of the ninteenth oil path 419 and the twenty-second oil path 422 is the same as the flow of the eighteenth oil path 418. A gate 204 o-f valve 200 is manually operated to open the ninteenth oil path 419 and close the twenty-second oil path 422 via a link 202 thereof when the shifting lever is at a reversing position or during engine braking.
Conversely, the ninteenth oil path 419 is closed and the twenty-second oil path 422 is opened when the shifting lever is at the forwarding position.
Also, the control valve 200 can be manually operated to partially close both the ninteenth oil path 419 and the twenty-second oil path 422 for driving at a rated speed and for engine braking when the car is either on a rugged road or the car is heavily loaded on a steep slope or a continuous rise-and-fall slope. For example, if gate 204 opens both oil paths 419 and 422 halfway, half of the oil from pump 60 flows through oil paths 418, 419 and 403, then through pump 40 to accelerate pump 40 to obtain the effect of engine braking, then through oil paths 404, 407, 421 and 420 and circles back to pump 60. Another half of the oil from pump 60 flows through oil paths 418, 422 and 420 and circles back to pump 60. Since there is always half of the oil from pump 60 entering pump 40, the braking extent of the ring gear 26 is rated, therefore, the car is running at a rated speed.
Generally, when the braking pedal is pressed, there is a clearance between the braking pedal and the floor of the car in order to avoid the pedal colliding with the floor. If the braking system does not function properly, the braking pedal shall pass over the clearance.
A ninth flow control valve 590 is provided on the twentieth oil path 420 for urgent braking when the braking system does not function properly. A link 522 of the ninth flow control valve 590 (see Fig. 5) connects other elements disposed below the pedal in order that the flow control valve 590 might be closed when the braking system does not function properly and -the braking pedal is pressed. Referring to Fig. 2C, the circuit for oil circling is interrupted and an extra braking effect is achieved.
A relief valve 590' is provided on a subpipe 420' which is communicated to the twentieth oil path 420 at two ends thereof for reducing the pressure of overpressurised oil. Furthermore, valve 590' provides the functions of automatically reducing the gear reduction ratio and absorbing impacts and shocks when the car is on a rugged road.
Generally, a driver utilises the engine braking when a car is going down a slope. Please refer to Fig.
2F. When the engine braking is needed, valve 200 closes oil path 422 and opens oil path 419. The oil flow from the first end of pump 60 flows through oil paths 418, 419 and 403, then through pump 40 and returns to pump 60 via oil paths 404, 407, 421 and 420 as indicated by the arrows in Fig. 2F. Since pump 40 is accelerated, the effect of engine braking is achieved.
Furthermore, if the engine has broken down -and it is required to push the car in the reverse direction, valve 200 is manually operable to close the ninteenth oil path 41-9 and open the twenty-second oil path 422 in order that pump 60 may obtain the desired circuit from the twenty-third oil path 423, in the mean time the shif-ting lever is at the neutral position to open the eighth flow control valve 580.
Referring to Fig. 1, a braking annular gear 48 is mounted on the planet pinion shafts 18. The braking annular gear 48 cooperates with braking claws 46 mounted on an inner wall of the gear box to fix the planet pinion shafts 18 during reversing. The transmission of power between the first planetary gear 10 and the second planetary gear 20 is interrupted and it is completely reliant on the first and the second braking pump 30 and 40 to transmit the power. During reversing, the power from the engine crankshaft 3 is transmitted to the rear propeller shaft 4 via the sun gear 12, the planet pinion 14, the ring gear 16, pump 30, pump 40, the ring gear 26, the planet pinion 14 and the sun gear 22 in sequence.
Referring to Fig. 2A, when the shifting lever is at the neutral position, the oil from pump 30 flows through oil paths 401, 41-1, 414, 412 and 406 and returns to pump 30 as indicated by the arrows shown in
Fig. 2A.
As shown in Fig. 2B, when the shifting lever is at the forwarding position under an engine idling condition, the flow from pump 30 via oil paths 401, 411, 413, 412, and 406 and returns to pump 30 as indicated by the arrows in Fig. 2B.
When the shifting lever is at the forwarding position and the accelerator is pressed and the critical point of free rotation is passed, effective driving begins. When the accelerator is pressed to a pre-determined extent, the control valve 540 is completely closed. Since flow control valve 520 is closed, there is no circling oil flow through pump 30 and pump 30 does not rotate. The gear reduction ratio is thus controlled by pump 40. The oil flow from pump 40 flows through oil paths 404, 407, 408, 409 and 410 and returns to pump 40. Furthermore, the oil flow from pump 60 flows through oil paths 418, 422 and 420 and returns to pump 60 as shown by the arrows in Fig. 2C.
As shown in Fig. 2D, when the shifting lever is at the reversing position and the accelerator is not pressed, the oil flows from the outlet of pump 30, passes through oil paths 401, 411, 413, 412 and 406 and returns to pump 30 as clearly shown by the arrows in
Fig. 2D.
As shown in Fig. 2E, when the accelerator is pressed to a pre-determined extent and valve 540 is completely closed, since valve 520 is open, about onefourth of the flow from pump 30 enters pump 40 via oil paths 401, 402 and 403 and circles back to pump 30 via oil paths 404, 405 and 406. The remaining three-fourths of the flow from pump 30 flows to pump 60 via oil paths 401, 402 419 and 418, then circles back to pump 30 via oil paths 420, 421, 407, 405 and 406 as clearly shown in Fig. 5E.
Please refer to Fig. 2F. When engine braking is needed, valve 200 closes oil path 422 and opens oil path 419. The oil that flows from pump 60 flows through oil paths 418, 419 and 403, and then passes through pump 40 and returns to pump 60 via oil paths 404, 407, 421 and 420 as clearly shown in Fig. 2F. Since pump 40
is accelerated, the effect of engine braking is achieved.
Please refer to Fig. 7. A braking valve 600 is mounted on the inner wall of the gear box. The braking valve 600 is communicated to the centrifugal pump 50 at one end thereof. An engaging member 608 of the braking valve 600 engages with an annular ratchet 610 provided on an outer periphery of the ring gear 16 of the first planetary gear 10 when the centrifugal pump 50 outputs working fluid in response to the rotation speed of the rear propeller shaft 4. As seen from Fig. 7, when the car reaches a certain speed, the force acts on a piston head 604-due to the working fluid .602 overcoming a spring 606 and forcing the engaging member 608 to mesh with the annular ratchet 610. Accordingly, pump 30 is rapidly braked due to the provision of the braking valve 600 and the annular ratchet 610.
In the present embodiment, an overdrive -transmission is achieved by changing the -gear number of the first planetary gear. For example, if the original gear numbers of both the first and the second planetary gears are 22, 66 and 88 (for the sun gear, the ring gear and the planetary carrier, respectively) and it is wished to obtain the gear reduction ratio of overdrive, then the original gear numbers of the first planetary gear are changed to 33, 66 and 99, respectively, noting that the gear numbers of the second planetary gear remain unchanged.
Please refer to Fig. 2C. If an overdrive transmission as well as the fifth flow control valve 550 are provided, then part of the flow from pump 40 will pass through the fifteenth oil path. When thecar has reached a certain speed, the first flow control valve 510 is completely closed. When the car reaches a pre-determined overdrive speed, the fifth flow control valve 550 begins to function and the gear reduction ratio thereof is controlled by the fifth flow control valve 550.
It is appreciated that the description of the operation of the present invention hereinafter is for the purpose of explanation only, not for limiting the present invention. The gear numbers of the sun gear and the ring gear and the effective gear number of the first planetary gear for both the first and the second planetary gears are 22, -66 and 88, respectively. The gear reduction ratio of the present invention is given for certain conditions, for example, when the flows of pumps 30 and 40 are one-fourth, two-fourths or threefourths of their full flows.
Please refer to Table 1. Table 1 shows the dimensions of each oil flow path and each oil pump of the embodiment as shown in Fig. 2A to 2F. Please notice that the oil paths and pumps are represented by corresponding numerals. The full flow is represented by 4/4.
Table 1 oil path or pump dimension oil path or pump dimension
30 4/4 412 4/4
40 4/4 413 4/4
60 4/4 414 4/4
401 4/4 414' 1/4
402 4/4 415 1/4
403 4/4 415' 1/4
404 4/4 416 1/4
405 4/4 416' 1/4
406 4/4 417 1/4
407 4/4 417' 2/4
408 2/4 418 4/4
408' 1/4 419 4/4
408" 3/4 420 4/4
409 4/4 420' -1/4
410 4/4 421 - 4/4
411 474 422 4/4
423 4/4
The operations under both the forwarding condition and the reversing condition are illustrated hereinbelow since the operations under neutral condition and idling condition have been detailed hereinbefore.
Furthermore, a dimension of a last portion 417' of the seventeenth oil path 417 is 2/4 (see Table 1) since 417' accepts the flows from the seventeenth oil path 417 and the fifteenth oil path 415 If 417' is directly communicated to the eighth oil path 408, the flow of 417' is 1/4.
Additionally, in order to obtain the effect of economical starting, the dimension of an oil path 408'' between an intersection of the eighth oil path 408 and the sixteenth oil path 416 and an an intersection of the eighth bit path 408 and the seventh oil path 407 is 3/4 (see Table 1 and Figs. 2A to 2F). The dimension of the eighth oil path 408 is 2/4 (see Table 1).
-(i) Forwarding:
Please refer to Table 2. The gear reduction ratio of the automatic transmission and the flows within oil paths and pumps are listed below in Table 2, wherein the overdrive is not discussed.
Table 2
control first planetary second planetary gear
system gear (relative gear (relative reduction
(flow) rotation sPeed) rotation speed) ratio * ** 540 510 12 16 & 30 28 28 26 & 40 20
1/4 3/4 6 2 0 0 0 0 6 : 0
0/4 3/4 6 0 3/2 3/2 3/2 3/2 4 : 1
0/4 2/4 6 0 3/2 3/2 1 3 2 : 1
0/4 1/4 6 0 3/2 3/2 1/2 9/2 4 : 3
0/4 0/4 6 0 3/2 3/2 0 6 1 : 1
The above gear reduction ratios are for an economical
control type provided without economical starting.
The gear reduction ratios listed below are'for an economical
control type provided with economical starting
1/4 2/4 6 2 0 0 0 0 6 : 0
0/4 2/4 6 0 3/2 3/2 1 3 2 :' 1
0/4 1/4 6 0 3/2 3/2 1/2 9/2 4 : 3 0/4 0/4 6 0 3/2 3/2 0 6 -1 : 1 rotates in a converse direction **: corresponding numerals according to the present invention
(ii) Reversing:
Please refer to Fig. 2E and Table 1. While in
reverse, after the accelerator is pressed to the pre
determined extent and valve 540 is closed, if the
engine crankshaft 3 meshes with the sun gear 12 of the
f-irst planetary gear 10 to rotate, for example, 4
cycles, the ring gear 16 of the first planetary gear 10 connects with pump 30 to rotate 1.33 cycles conversely.
The amount of flow of pump 30 is 1.33 cycles * 4/4 per cycle = 5.33/4, wherein three-fourths of the flow from pump 30 enters pump 60, therefore, an amount of 4/4 of the 5.33/4 flows to pump 60 to rotate pump 60 1 cycle conversely and the remainder, 1.33/4, flows to pump 40 to rotate pump 40 0.33 cycles in the same direction as the crankshaft. The ring gear 26 of the second planetary gear 20 rotates 0.33 cycles to rotate the sun gear 22 of the second planetary 1 cycle conversely.
Therefore, a reversing gear reduction ratio of 4 : 1 is obtained. If an overdrive -with a gear reduction ratio of-0.75 : 1 is provided, the final gear reduction ratio is 3 : 1.
If the present invention is provided on a small automobile and the securing pump 60 is not necessarily equiped, the full flow of the first braking pump 30 is reduced to either 1/4 or 1/3. - If the apparatus is provided on a motorcycle in which the reversing function is not needed, pump 30 may be removed 'therefrom and pump 40 only is utilised.
Furthermore, the braking gear in the first planetary gear is permanently fixed on the gear box with the provision of the oil pipes of Figs. 2A to 2F.
Additionally, oil paths 413 and 414 are communicated to pump 40 directly with the corresponding valves 530, 540 and 150 provided therein and the desired dimensions of each oil path depends on the practical necessity. Also, the braking gear of the second planetary gear can be fixed onto the gear box instead of fixing onto the first planetary gear.
When the apparatus according to the present invention is utilised in an industry, securing pump 60 is not required. Either of the braking gears of the first or the second planetary gears is selected (depending on the user's will) to be permanently fixed.
The braking gear of the planetary gear which is not fixed is provided with a braking pump, a manually operable flow control valve, a relief valve and a check valve for a stepless automatic transmission.
Please notice that the ring gear of the first planetary gear may also function as a driven gear, the planet carrier functions as a braking gear and the sun gear function as a driving gear. With respect to this, the ring gear of the second planetary gear functions as a driving gear, the planet carrier functions as a braking gear and the sun gear functions as a driven gear. Furthermore, according to the present invention, the planet carrier or the ring gear can function as a driving gear without departing from the scope and spirit of the present invention.
While the present invention has been explained in relation to its preferred embodiment, it is to be understood that various modifications thereof will be apparent to those skilled in the art upon reading this specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover all such modifications as fall within the scope of the appended claims.
Claims (11)
1. A method for providing an automatic transmission comprising the steps of:
(a) sensing a rotation speed of a rear propeller shaft by means of a sensing means and outputting an amount of pressurised working fluid in response to said rotation speed;
(b) closing at least one flow control valve to a certain extent due to the working fluid;
(c) reducing a flow of an oil path system which comprises said flow control valve(s) to a certain extent to reduce the rotation speed of, or to stop, at least one braking pump;
(d) braking at least one planetary gear to a.
certain extent by a corresponding number of braking gears thereof; and
(e) obtaining a gear reduction ratio in response to a reactive force obtained from said planetary gear(s) due to the braking of said braking gear(s).
2. An apparatus for providing an automatic transmission, comprising a first planetary gear and a second planetary gear, a first braking pump and a second braking pump, a sensing means, an oil path system and a first flow control valve provided on said oil path system, characterised in that -each of said first and second planetary gears has a sun gear, a planet carrier and a ring gear which are respectively accommodated to function as either a driving gear, a driven gear or a braking gear of said first planetary gear and said second planetary gear; wherein a driven gear in said second planetary gear relates to a corresponding driving gear in said first planetary gear, a driving gear in said second planetary gear relates to a corresponding driven gear in said first planetary gear, a braking gear in said second planetary gear relates to a corresponding braking gear in said first planetary gear; said driving gear of said first planetary gear is mounted on an engine crankshaft and said driven gear of said second planetary gear is mounted on said rear propeller shaft; a rotor shaft of said first braking pump is connected to said braking gear- of said first planetary gear, a rotor shaft of said second braking 'pump is connected to said second planetary gear; both said first braking pump and said second braking pump are communicated to said oil path system and controlled by said sensing means;
said sensing means is mounted on said rear propeller shaft for sensing the rotation speed of said rear propeller shaft and outputs various amounts of pressurised working fluid in response to said rotation speed of said rear propeller shaft to close said first flow control valve so as to brake said first and second braking pumps via said oil path system; said braking gears of said first and second planetary gears being braked by said first and second braking pumps, respectively, said driven gears of said first and said second planetary gears obtaining a reactive force due to the braking of said braking gears and obtaining a gear reduction ratio for transmission.
3. An apparatus according to claim 2, wherein said sun gear of said first planetary gear functions as the driving gear, said planet carrier of said first planetary gear functions as the driven gear, said ring gear of said first planetary gear functions as the braking gear; -said sun gear of said second planetary gear functions as the driven gear, said planet carrier of said second planetary gear functions as the driving gear, said ring gear of said second planetary gear functins as the braking gear;
each planet pinion of said first planetary gear shares a planet pinion shaft and said planet carrier with each planet pinion of said second planetary gear; said sun gear of said first planetary gear is mounted on an engine-crankshaft; said ring gear of said first planetary gear is connected to a rotor shaft of said first braking pump via a first ring gear carrier;said ring gear pf said second planetary gear is connected to a rotor shaft of said second braking pump via a second ring carrier; said sun gear of said second planetary gear is mounted on said rear propeller shaft; a centrifugal pump is provided on said rear propeller shaft for sensing the rotation speed of said rear propeller shaft and function as said sensing means;
a first end of a first oil path is communicated to an outlet of said first braking pump, a first end of a second oil path is communicated to a second end of said first oil path, a first end of a third oil path is communicated to a second end of said second oil path, a second end of said third oil path is communicated to an inlet of said second braking pump; a first end of a fourth oil path is communicated to an outlet of said second braking pump, a first end of a fifth oil path is communicated to a second end of said fourth oil path, a first end of a sixth oil path is communicated to a second end of said fifth oil path, a second end of said sixth oil path is communicated to an inlet of said first braking pump;
a first end of a seventh oil path is communicated to said second end of said fourth oil path, a first end of an eighth oil path is communicated to a second end of said seventh oil path, a first end of a ninth oil path is communicated to a second end of said eighth oil path, a second end of said ninth oil path is communicated to an oil tank, a first end of a tenth oil path is communicated to said first end of said third oil path, a second end of said tenth oil path is communicated to said oil tank;;
said first flow control valve is provided on said eighth oil path, said first flow control valve is communicated to said centrifugal pump at one end thereof, said first flow control valve is closed to various extents by said centrifugal pump;
a second flow control valve for reversing is provided on said second oil path, said second flow control valve is opened when a shifting lever is at a reversing position, said second flow control valve is closed when the shifting lever is not at the reversing position.
4. An apparatus according to claim 3, further comprising an eleventh oil path communicated to said second end of said first oil path at a first end thereof, a first end of a twelfth oil path being communicated to said first end of said sixth oil path, a first end and a second end of a thirteenth oil path being respectively communicated to a second end of said eleventh oil-path and a second end of said twelfth oil path; a fourteenth oil path being communicated to said eleventh oil path and said twelfth -oil path at two ends thereof;
a third flow control valve for neutral being provided on said fourteenth oil path, said third -flow control valve being- opened when the shifting lever is at a neutral position, said third flow control valve being closed when the shifting lever is not at the neutral position;
a fourth flow control valve being provided on said thirteenth oil path; said fourth flow control valve being closed if the accelerator is pressed to a predetermined extent.
5. An apparatus according to claim 3, further comprising a fifth flow control valve for overdrive, said fifth flow control valve being provided on a fifteenth oil path which is communicated to said eighth oil path at two ends thereof, said fifth flow control valve being communicated to said centrifugal oil pump at one end thereof and functions as said first fl-ow control valve; said fifth flow control valve starting to function when the car has reached a pre-determied overdrive speed.
6. An apparatus according to claim 3, further comprising a sixth flow control valve for economical starting, said sixth flow control valve being provided on a sixteenth oil path which is communicated to said eighth oil path at two ends thereof; said sixteenth oil path being closed when an economical starting is desired.
7. An apparatus according to claim 3, further comprising--a seventh flow control valve for lowering the gear reduction ratio under extreme conditions, said seventh flow control valve being provided on a seventeenth oil path which is communicated to said eighth oil path at two ends thereof; said seventh flow control valve being manually opened when a lowering of gear reduction ratio is needed for extreme conditions.
8. An apparatus according to claim 3, further comprising a securing oil pump for engine braking, said securing pump being mounted on said rear propeller shaft via a rotor shaft thereof, a first end of an eighteenth oil path being communicated to a first end of said securing oil pump, a second end of said eighteenth oil path being communicated to a first side of a split-directional flow control valve, a first end of an nineteenth oil path being communicated to a second side of said split-directional flow control valve, a second end of said nineteenth oil path, being communicated to said second end of said secondoil path, a first end of a twentieth oil path being communicated to a second end of said securing oil pump, a first end of a twenty-first oil path being communicated to a second end of said twentieth -oil path, a second end of said twenty-first oil path being communicated to said second end of said seventh oil path;
a first end of a twenty-second oil path' being communicated to said second side of said splitdirectional flow control valve, a second end of said twenty-second oil path being communicated to said second end of said twentieth oil path, a twenty-third oil path being communicated to said twenty-second oil path at two ends thereof;
an eighth flow control valve being provided on said twenty-third oil path, said eighth flow control valve being opened when the shifting lever is at the neutral position or the reversing position, said eighth flow control valve being closed when the shifting lever is neither at the neutral position nor at the reversing position; a check valve being provided on said twentysecond oil path between said two ends of said twentythird oil path, the flow within said twenty-second oil path being restrained so that the working fluid is only flowable from said first end of said twenty-second oil path to said second end of said twenty-second oil path;
a ninth-flow control valve being provided on said twentieth oil path for braking when the braking systemis not functioning properly, said ninth flow control valve being closed when the braking system is not functioning properly and the braking pedal is pressed and passes over a clearance between the braking pedal and the floor of the car;
said split-directional flow control valve being arranged such that a total amount of flow of said nineteenth oil path and said twenty-second oil path is the same as the flow of said eighteenth oil -path; said nineteenth oil path being opened and said twenty-second oil pathtbeing closed when the shifting lever is at the
reversing position or under engine braking, said
nineteenth oil path being closed and said twenty-second
oil path being opened when the shifting lever is at the
forwarding position; said split-directional flow
control valve being manually operable to partially
close both said nineteenth oil path and said twenty
second oil path for driving at a rated speed.
9. An apparatus according to claim 3, further
comprising a braking annular gear mounted on said
planet pinion shafts, said braking annular gear
cooperating with braking ratchets mounted on an inner
wall of the gear box to fix said planet pinion shaft.-
10. An apparatus according to claim 3, further -comprising a braking valve mounted on said inner wall
of the gear box, said braking valve being communicated
to said centrifugal pump at one end thereof; an
engaging element of -said braking valve being engaged
with an annular ratchet provided on an outer periphery
of said ring gear of said first planetary gear when
said centrifugal pump outputs working fluid in response
to said rotation speed of said rear propeller shaft.
11. An apparatus substantially as hereinbefore described with reference to and as shown -in the
accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8918724A GB2236364A (en) | 1989-08-16 | 1989-08-16 | Automatic transmission comprising planetary gearing and braking pumps |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8918724A GB2236364A (en) | 1989-08-16 | 1989-08-16 | Automatic transmission comprising planetary gearing and braking pumps |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8918724D0 GB8918724D0 (en) | 1989-09-27 |
| GB2236364A true GB2236364A (en) | 1991-04-03 |
Family
ID=10661739
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8918724A Withdrawn GB2236364A (en) | 1989-08-16 | 1989-08-16 | Automatic transmission comprising planetary gearing and braking pumps |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2236364A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5807199A (en) * | 1996-02-12 | 1998-09-15 | Keller; Gottfried | Hydro-mechanical gearbox |
| WO2009018982A2 (en) * | 2007-08-09 | 2009-02-12 | Tecnotal Ag | Drive device for vehicles, preferably motor vehicles |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB221624A (en) * | 1923-08-07 | 1924-09-18 | William Jameson Turner | Improvements in variable speed power transmitting gear |
| GB365585A (en) * | 1930-07-21 | 1932-01-21 | William George Shipwright | An improved form of power transmission clutch and gearing mechanism |
| GB466380A (en) * | 1935-12-18 | 1937-05-27 | Manuel Andres Gonzalez | Improvements in or relating to automatic progressively variable speed gears |
| GB676894A (en) * | 1949-11-12 | 1952-08-06 | Cecil Vance Bowles | Variable speed gear box |
| GB833273A (en) * | 1956-10-18 | 1960-04-21 | Ford Motor Co | Constant speed drives |
| GB1226608A (en) * | 1967-05-11 | 1971-03-31 |
-
1989
- 1989-08-16 GB GB8918724A patent/GB2236364A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB221624A (en) * | 1923-08-07 | 1924-09-18 | William Jameson Turner | Improvements in variable speed power transmitting gear |
| GB365585A (en) * | 1930-07-21 | 1932-01-21 | William George Shipwright | An improved form of power transmission clutch and gearing mechanism |
| GB466380A (en) * | 1935-12-18 | 1937-05-27 | Manuel Andres Gonzalez | Improvements in or relating to automatic progressively variable speed gears |
| GB676894A (en) * | 1949-11-12 | 1952-08-06 | Cecil Vance Bowles | Variable speed gear box |
| GB833273A (en) * | 1956-10-18 | 1960-04-21 | Ford Motor Co | Constant speed drives |
| GB1226608A (en) * | 1967-05-11 | 1971-03-31 |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5807199A (en) * | 1996-02-12 | 1998-09-15 | Keller; Gottfried | Hydro-mechanical gearbox |
| WO2009018982A2 (en) * | 2007-08-09 | 2009-02-12 | Tecnotal Ag | Drive device for vehicles, preferably motor vehicles |
| WO2009018982A3 (en) * | 2007-08-09 | 2009-12-10 | Tecnotal Ag | Drive device for vehicles, preferably motor vehicles |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8918724D0 (en) | 1989-09-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |