Title of Invention

TRANSMISSION SYSTEM FOR CONSTANT OUTPUT SPEED

Abstract

A transmission system for constant output speed, irrespective of input speed, includes a differential gear unit for input, a planetary gear unit, one hydraulic pump rotating with the first output shaft of the differential gear unit and one of the three gear elements of the planetary gear unit, and the second output shaft of the differential gear unit rotating with the second gear element, and a flow control valve with variable orifice to control the fluid pressure exerted by the hydraulic pump, and regulate the speed of the third gear element for the desired constant output speed.

Full Text

> TECHNICAL FIELD [0001]. The present invention is directed to a transmission system for constant output speed, irrespective of varying input speed, basically intended for driving power generators used for supplying power for electronic equipments, such as signal processors, control units, communication devices etc. and also for charging D.C. Power packs, where the constant frequency and voltage is of utmost importance. The system will find extremely useful in aircrafts, automobiles, specially for the military vehicles engaged in war related operations and in general for power producing units. As example the life of an automobile battery can be easily doubled if the charging of the battery is conducted at a constant voltage throughout the time, right from slow speed to max: speed. BACKGROUND OF THE INVENTION. [0002]. As on today there is no mechanical system which can provide a constant output speed when the prime mover operates in a vast speed range of, say 1200 rpm to 6000 rpm. There are certain mechanical devices, such as flexible pulley, the effective diameter of which can be adjusted to maintain the speed at almost constant level by incorporating a speed sensor and an electronic control circuit. In this system the range of operation is extremely limited and the system can be used only for transmitting light load. There are also hydraulic systems incorporating a hydraulic pump and a hydraulic motor, the output speed of which can be controlled to almost a constant level, based on the feed back from a tacho generator or sensor. Here also the range of operation is limited, and more particularly the loss of power by converting the mechanical power to hydraulic power is in the range of 30% to 35%; and hence can be hardly used. There are D C motors which can be driven by the electric power generated by the prime mover. Although in this case the range of operation is quite satisfactory, the loss of power while converting the mechanical energy into electrical energy is about 30%. There are also A C motors which can operate at variable speed by simultaneously adjusting both voltage and frequency, by changing the firing angle and the gate turn off interval of the thyristors etc. Here again the conversion loss from mechanical into electrical energy is about 25%. These conventional systems can operate neither successfully nor economically for the purpose of constant output speed, as shown above. U S patent 631235 incorporates a hydraulic pump and motor, to run the motor at constant speed by adjusting the fluid pressure delivered by the hydraulic pump. But the efficiency of the unit is reported to be appro. 65%. Similarly the Canadian patent 1238102 incorporates a variable pulley system, the effective diameter of which is adjusted automatically by a worm gear and sensor. The deficiency in this system is it's narrow operating range, and the inability to transmit heavy load. SUMMARY OF THE INVENTION [0003]. This invention discloses a transmission unit which provides for constant output speed irrespective of the varying speed of the prime mover. This was made possible in the system by incorporating a differential unit having it's output shafts, connected to sim gear and planet carrier respectively of a planetary gear system and thus enabling the sun gear and planet carrier to maintain a mathematical relationship with the input speed as shown in the following pages. The hydraulic pump driven by the sim gear decides the resistance offered to the movement of the sun gear, by adjusting the flow control valve provided in the delivery line and thus adjusting the operating speed of the sun gear, to maintain a constant speed for the annulus of the planetary unit. The system maintains high transmission efficiency in the order of 90%. [0004]. In view of the above the present invention is directed to a transmission system for constant output speed including a differential gear unit for input, a planetary gear unit, one hydraulic gear pump, an electronic control unit to selectively control the flow and control the resistance exerted by the fluid pressure and there by control the speed of the ring gear of the planetary gear unit. [0005]. Further scope of the applicability of the present invention will become apparent frm the following detailed description, claims, and drawings. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art. [0006]. The present invention will become more fullnderstood frm the detailed description given here below, the appended claim, and the accompanying drawings in which: [0007]. Fig. 1 in sheet no. lis a general assembly of the equipment in accordance with this invention. [0008]. Fig. 2 in sheet no.2 is a sectional view of the differential gear unit with the hydraulic pump attached to the left side output shaft and the pair of gears coupling the planetary gear unit on either side. [0009]. In sheet no.3 Fig. 3 is the sectional view of the planetary gear unit with each of the input gears on either side coupling the output shaft of the differential gear unit and the output gear to be coupled to the drive shaft of the driven machine. [0010]. Detailed description of the preferred embodiment. [0011]. The following description of the present invention includes the preferred embodiment of the transmission system to be attached to a prime mover. It should be appreciated that the invention is equally applicable in the other areas where the system can be used in a different manner by varying the roles of sim gear, planet carrier and annulus to achieve the desired architecture. [0012]. The details of the differential gear unit, as shown in Fig.2 includes a bevel gear 7 for the power input, the driven bevel gear 1 attached to the differential body 3 enclosing the pinions, one of the two revolving pinions 2, one of the two rotating pinions 6, the hydraulic pumpl3, the driving helical gear 5 on the right side output shaft of the differential gear unit meshing with the driven helical gear 4, and the driving helical gear part 11 on the left side output shaft of the differential gear imit meshing with the driven helical gear part 12. Part 10 is the flow control valve with variable orifice fixed in the delivery line of the hydraulic gear pump delivering fluid into the reservoir part 9, and part 8 is the return line from the reservoir to the suction side of the gear pump. [0013]. The details of the planetary gear unit as shown in Fig. 3 includes the main shaft part 19 of the unit, the bush part 22 fixed on the main shaft and rotating with the planet carrier part 16 carrying the planets part 15 and part 21 rotating with the planet carrier while rotating about their own axis, the sun gear part 14 freely mounted on the main shaft, meshing with the planet gears and rotating with the input gear part 20 meshed with the left side driven gear 12 of the differential gear unit, the input gear part 24 on right side, fixed on the main shaft, and meshing with the right side of the driven gear 4 of the differential gear unit, the output gear part 23 freely mounted on the main shaft with the bronze bush part 18 and rotating with the ring gear (annulus) part 17 meshing with the planet gears. [0014]. When the power from the prime mover is transmitted to the differential unit through the bevel gear pair, the outp shafts of the unit start rotating. The rotation of the output shafts follows the formula 2N = Nl + N2 Formula(l) whereas N is the prime mover speed in RPM (hereafter referred to as speed). Nl is the left side output shaft speed and N2 is the right side output shaft speed. [0015]. In the case of planetary gear if XI is the speed of the sun gear, X2 is the speed of the planet carrier, and X is the speed of ring gear (annulus), XI = 4.5 X2 - 3.5 XFormula (2). (The annulus is connected to the driven machine) Whereas (Zl + Z2)/Z1 = 4.5 and Z2/Z1 = 3.5; Zl = No. of teeth on sun gear = 24 and Z2 = No. of teeth on annulus = 84 [0016]. If the prime mover speed is 1200, and the required output speed is 3000, on applying the formula (1), X2 will be equal to (1200 x 2-XI). On applying formula (2) XI = 4.5 X2 - 3.5 X. Therefore XI = 4.5 (1200 x 2 - XI) - 3.5 X. whereas X = 3000. Therefore Xl= 55. X2 = 2400 - 55 = 2345. Similarly if the prime mover speed is 1500, on applying Formula (1) X2 will be (1500 X 2 - XI). On applying formula (2) XI - 4.5 X2 - 3.5 X. Therefore XI = 4.5(1500 X 2 - XI) - 3.5 X whereas X= 3000. Therefore XI = 545 and X2 = 3000 - 545 = 2455. In table 1 below the values of XI and X2 and also the value of X have been given against the [0017]. From the Table (1) given above it can be noted that the value of XI ranges from 55 to 7909 in order to maintain constant speed of 3000 rpm for the annulus connected to the driven machine. [0018]. It may be specially noted that the tendency of the sunear will be always to increase it's speed so that the output speed of the unit will tend to come down. Therefore there is no possibility for the speed of the sunear to come down during operation. [0019]. The electronic sensor attached to the annus senses the speed of the armulus and actuates the flow control valve in the fluid delivery line of the gear pumprough the electronic control circuit, to adjust the speed of the sun gear to the values indicated above so that the speed of the annulus will be always maintained at 3000 rm. During the operation of the system if there is any change in the prime mover speed the speed sensor will actuate the flow control valve through the control circuit and correct the speed of the sun gear so that the annulus speed will be maintained at 3000 rpm. If the output speed has to be kept at a different level the control circuit can be adjusted accordingly so that the value of XI will be corrected to suit the newly set value of X. [0020]. The foregoing discussion discloses and describes the exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims that various changes, modifications, and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claim. I claim 1 .A transmission system for constant output speed irrespective of the input speed comprising: a differential gear unit coupled to the power input from the prime mover; a planetary gearinit drivably intercoupling it's sun gear with the first output shaft of said differential gear unit, and the planet carrier with the second output shaft, said planetary gear unit including a sun gear, a ring gear, a planet carrier, and at least one planet gear mounted on said planet carrier to rotate with and relative to said planet carrier and meshed with the sun gear and ring gear; wherein, a hydraulic pump coupled to the first output shaft of said differential gear unit, and a flow control valve with variable orifice controlling the flow of fluid and the resistance exerted by the fluid pressure on sun gear to control the speed of the ring gear of said planetary gear unit, coupled to the driven machine, to provide constant speed for the driven machine. 2. The transmission system for constant output speed of claim 1 wherein one of the prime movers includes a vehicle having it's engine operating at varying speed.

Documents:

2591-CHE-2008 FORM-13 28-07-2011.pdf

2591-CHE-2008 AMENDED CLAIMS 21-05-2014.pdf

2591-CHE-2008 AMENDED PAGES OF SPECIFICATION 21-05-2014.pdf

2591-CHE-2008 EXAMINATION REPORT REPLY RECEIVED 21-05-2014.pdf

2591-che-2008 abstract.pdf

2591-che-2008 claims.pdf

2591-che-2008 correspondence others.pdf

2591-che-2008 description (complete).pdf

2591-che-2008 drawings.pdf

2591-che-2008 form-1.pdf