Abstract:
The invention relates to a continuously variable transmission (CVT) system, governed by an inertia mechanism that provides an additional degree of freedom, conferring dynamic properties on the transmission. The complete system includes three distinct subsystems. The first subsystem transforms the rotating movement from the drive system into a movement with oscillating angular speed and regulates the amplitude of said movement. The oscillating rotation at the output of the first subsystem is used to drive the second subsystem, which acts as a regulating element by means of the inertia mechanism. In this manner, the second subsystem acts as a torque-regulating element, providing a signal representing the oscillating angular speed at the output shaft thereof. The oscillating rotation at the output of the second subsystem is rectified in the third subsystem, thereby providing a signal representing angular speed in a single direction of rotation at the output shaft.

Description:
OBJECT OF THE INVENTION 
       [0001]    This invention, as expressed in the heading of this descriptive memory refers to a continuously variable transmission system with inertia regulation. 
         [0002]    It basically includes three subsystems that are related to each other, in a manner that the first of them provides an oscillating angular speed with variable amplitude, a second subsystem that includes an inertia mechanism and a third subsystem with movement rectification, which provides a single direction of rotation at its output. 
         [0003]    Since this is a continuously variable transmission system, it includes a limited number of transmission ratios within the possible gear ratio interval, while a continuous variation in the transmission ratio may be obtained. 
         [0004]    This invention has a direct application in the automobile industry, in any industrial application that requires a power transmission system as well as in any other application that requires torque regulation and changes in speed. 
       BACKGROUND OF THE INVENTION 
       [0005]    Fixed ratio transmissions, regardless of whether they are manual or automatic, include a discrete number of transmission ratios or gears. In comparison with conventional transmissions, in a continuously variable transmission or CVT, the transmission ratio between the input and output shafts may be progressively varied in a specific interval of possible ratios. The possibility of incorporating a limited number of transmission ratios provides an added parameter in order to optimize one or several variables of the vehicle. This way, with a specific variation in the transmission ratio, we can achieve conditions of high power, low consumption or a compromised ratio between both variables. 
         [0006]    One possible classification establishes two large groups of continuously variable transmissions, the cinematic and dynamic types. In a cinematic CVT, the progressive change in transmission ratio is carried out on a specific element, resulting in the transmission ratio being fixed at a specific value and requires acting upon the element once again in order to change it. On the other hand, in a dynamic type CVT, as well as being able to act upon a cinematic regulation element, the transmission ratio also depends on the external conditions to which the transmission is subjected to. This means that the transmission ratio will be determined by the cinematic characteristics as well as by variables such as the speed of the input shaft or the resistant torque exerted on the output shaft. 
         [0007]    The dynamic type continuously variable transmissions originate from the innovative work carried out by Hunt, which were published in GB patents 21,414 of 1912 and GB Patent 19,904 of 1913, where an inertia type transmission system is described with the dynamic transmission principle but without a direct application like CVTs. 
         [0008]    The first documented continuously variable type dynamic transmission originates from the work of Constantinesco, described in his GB Patent 185,022 of 1922 and in his subsequent patents, which describe methods for improving the power transmission of the primary shafts of vehicles that operate using internal combustion engines. In these transmissions, the torque is regulated using a pendulum or other inertia elements. 
         [0009]    Chalmers, in U.S. Pat. No. 1,860,383 of 1932 introduces his oscillating torque transmission system with movement of the output shaft in a single direction of rotation. In this case, the regulating element consists of a series of satellite gears with eccentric masses that generate an oscillating torque at the output due to the inertia forces these masses are subjected to. Similar type transmissions were designed by Tam, 1992 (U.S. Pat. No. 5,134,894) and Fernandez, 1998 (U.S. Pat. No. 5,833,567), which were also based on satellite gears with eccentric masses. Also with oscillating masses, but in this case without these carrying out complete rotations about themselves, we have the torque exchange patent of 1982 owned by Shea (U.S. Pat. No. 4,336,870); this transmission includes two symmetric masses shaped like a cam that oscillate, thus regulating the torque of the output shaft. Also based on inertia regulation using eccentric masses we have William&#39;s torque converter of 1971 (U.S. Pat. No. 3,581,584). 
         [0010]    Two dynamic type transmission patents exist previous to the one mentioned above that use the same principle of operation to solve different technical problems. The first one is U.S. Pat. No. 5,860,321 of 1999 provided by Williams, where he proposes new solutions for rectifying movement using a differential rectifier with two free wheels as well as specific configurations and new technical solutions focussed on increasing the compactness as well as the efficiency of the power transmission. The second transmission of this type provided by Lester in 2000 (U.S. Pat. No. 6,044,718) proposes solutions among which a power transmission regulation system stands out. The complete system is a CVT with inertia regulation and with the possibility of being coupled. 
       SUMMARY OF THE INVENTION 
       [0011]    The invention consists of a continuously variable transmission system with inertia regulation. Regulation is carried out using an inertia mechanism comprised of an epicyclic train that provides an additional degree of freedom. A specific mass is added to the element of the epicyclic train that includes this degree of freedom, which provides a dynamic character to the transmission and causes the train to act as a regulating element of the output shaft resistant torque. The complete system includes three different subsystems. A first subsystem that converts the signal provided by the drive system into an oscillating angular speed signal while it regulates the amplitude of said speed signal. This angular speed is used to drive the epicyclic train, which constitutes the second subsystem and is the inertia regulation mechanism for the transmission. This way, the second subsystem provides an oscillating torque regulated signal. The oscillating signal at the output of the second subsystem must be rectified in the third subsystem. In this manner, an angular speed signal in a single direction of rotation is finally obtained at the output shaft. Thus, a unidirectional torque capable of overcoming the resistant torque is applied at the transmission output shaft. This way, the complete system provides a torque that is adapted to the operating conditions it is subjected to such as the angular speed of the transmission input shaft as well as the resistant torque at the output shaft. Therefore, the invention consists of a dynamic type continuously variable transmission system with an oscillating nature. 
         [0012]    The transmission system described in the object of this patent includes many advantages, among which the following are highlighted:
   It does not require using any type of clutch system.   The transmission system regulates itself providing a change ratio between the output and input shafts that is most adequate for the demands that the system is subjected to.   Since this is a continuously variable transmission system, it includes a limited number of transmission ratios within the interval of possible change ratios.   A continuous variation of the transmission ratio can be obtained in order to achieve specific operating conditions of high power, low consumption or a compromise relation between both variables.   
 
         [0017]    From a commercial point of view, the characteristics of this transmission system are of great interest to the industry. 
         [0018]    This transmission system has a direct application in the automobile industry, in any industrial application that requires a power transmission system as well as in any other application that requires torque regulation and speed changes. 
         [0019]    In order to provide a better explanation of this descriptive memory and as an integrating part thereof, figures are included below, which in an illustrative and not limiting manner represent the object of this invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    FIG.  1 .—Consists of a detailed schematic representation of the three subsystems that comprise the complete transmission and the manner in which these are connected. 
           [0021]    FIG.  2 .—Consists of a schematic representation of subsystem S 1  corresponding to the driving and amplitude regulation mechanism. 
           [0022]    FIG.  3 .—Consists of a schematic representation of subsystem S 2  corresponding to the transmission&#39;s inertia regulation mechanism. 
           [0023]    FIG.  4 .—Consists of a schematic representation of subsystem S 3  corresponding to the oscillating movement rectification at the inertia regulation mechanism&#39;s output. 
           [0024]    FIG.  5 .—Represents the transmission flow of movement in a determined oscillating direction of the output shaft of subsystem S 2 . 
           [0025]    FIG.  6 .—Represents the transmission flow of movement in the direction opposite the oscillation with respect to the previous output shaft of subsystem S 2 . 
           [0026]    FIG.  7 .—Consists of a schematic representation of the driving mechanism for the reference position corresponding to the minimum oscillation amplitude. 
           [0027]    FIG.  8 .—Consists of a schematic representation of the driving mechanism for the position corresponding to the maximum oscillation amplitude. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    The inertia element of the developed dynamic CVT is comprised of an epicyclic reducer with mass added to the crown. Said epicyclic reducer is inserted upside down into the CVT; therefore, the reducer&#39;s input shaft is connected to the satellite holder and the output shaft to the planet. Therefore, in an assembly of this type, the epicyclic reducer would be multiplying the input speed. 
         [0029]    The transmission regulation is based on the aforementioned property of the inertia element and the assembly. When acceleration is applied to the satellite holder while the planet is maintained blocked, the crown&#39;s response is to accelerate with a similar type of outcome. Due to the acceleration experienced by the crown and while this acceleration lasts, a torque is generated at the planet. Once the crown acceleration process ceases, the torque at the planet is null. 
         [0030]    As a consequence, by subjecting the satellite holder to a speed law that produces continuous accelerations, a resistant torque can be overcome at the output shaft. For this purpose, an angular speed law is used at the input shaft in the form of an oscillating signal, which is generated by means of a driving mechanism. At the same time, the driving mechanism regulates the amplitude of said angular velocity. The signal at the planet also has an oscillating nature; therefore, a movement rectifying mechanism is required. 
         [0031]    The crown movement carries with it an additional degree of freedom. The adding of mass to the epicyclic train&#39;s crown allows said element to become a power regulation inertia mechanism. This regulation consists of cyclic power accumulations and cessions that allow the transmission to adapt to each one of the operating conditions it is subjected to. 
         [0032]    As seen in the  FIG. 1 , the complete transmission system includes three subsystems positioned in series. 
         [0033]    The purpose of the first subsystem S 1  ( FIG. 2 ) is to transform the signal originating from the drive system through shaft E 1  ( FIGS. 1 and 2 ) into an angular oscillating speed signal with a variable amplitude at shaft E 2  ( FIGS. 1 ,  2  and  3 ); this shaft is the input to the second subsystem S 2  ( FIG. 3 ). Bar B 1  ( FIGS. 1 and 2 ) consists of a handle with a fixed radius R, which transmits the circular movement of its end to control gear EC ( FIGS. 1 and 2 ). This EC element is engaged with the control crown CC ( FIGS. 1 and 2 ) and spinning about the inner face of the crown, while said crown is fixed in its position as determined by the driving element EA ( FIGS. 1 and 2 ). Said EA element uses a worm gear to drive the outer face of control crown CC in order to control its relative position with respect to the reference position, corresponding for example, to the minimum oscillating amplitude ( FIG. 7 ). Bar B 2  ( FIGS. 1 and 2 ) is joined at a point P ( FIGS. 1 and 2 ) to the EC, with said point located at a radius R from the centre of the EC. The union at point P is carried out in such a manner to allow the relative turn between the EC elements and B 2 . 
         [0034]    In the previous arrangement of subsystem  51 , the diameter of control gear EC is equal to the radius of the inner face of control crown CC. Under this configuration, the hypocycloid curve generated by point P and therefore, the end of bar B 2  at said point, degenerates to a straight line that is described by the inner diameter of control crown CC. Driving shaft EA and modifying the position of crown CC with respect to the reference position, the different possible diameters are described. This way, the oscillation transmitted through bar B 2  to counterweight B 3  ( FIGS. 1 and 2 ) is a function of the described diameter and will vary from an oscillation corresponding to a minimum amplitude at the reference position ( FIG. 7 ) to that which generates a maximum amplitude ( FIG. 8 ), and which corresponds to an amplitude that is out of phase at a right angle with respect to the reference angle. 
         [0035]    The second subsystem S 2  ( FIG. 3 ) uses the oscillating signal at the output of the first subsystem S 1 , acting as a torque regulating element by means of an inertia mechanism consisting of an epicyclic train, to which a mass M is added at crown C ( FIGS. 1 and 3 ). The satellite holder PS is joined to satellites SA 1 -SA 3  by means of the corresponding shafts ESA 1 -ESA 3  as shown in  FIGS. 1 and 3 . These satellites are engaged to crown C as well as to planet PL ( FIGS. 1 and 3 ), in a manner so the oscillating movement is transmitted to both elements. A mass M is uniformly added to crown C, with which said crown acquires the function of the transmission&#39;s inertia regulation element. Two predominant power transmission modes exist in subsystem S 2 , through which power is transmitted from the E 1  input shaft to the E 4  output shaft ( FIGS. 1 and 4 ). The power is transmitted in a manner that the law of oscillating angular accelerations that is exerted over the crown causes accelerations and decelerations of the crown associated with kinetic energy accumulations and cessions of subsystem S 2 . In the first of the operating modes, the power supplied to the transmission through shaft E 1  is used to accelerate crown C, which accumulates kinetic energy and in providing torque to output shaft E 4 . In the second mode, the power supplied by input shaft E 1  as well as the power released by crown C as it decelerates are used to supply torque to output shaft E 4 . A brief transition period exists between these two main modes of operation. 
         [0036]    The third subsystem S 3  ( FIG. 4 ) transforms the oscillating signal coming from subsystem S 2  into a single direction of rotation. This subsystem S 3  consists of a rectifier mechanism that is based on free wheels or any other type of mechanical diodes. The movement of shaft E 3  ( FIGS. 1 ,  3  and  4 ), output shaft of subsystem S 2  and input to subsystem S 3 , transmits its rotating movement to gear ER 2  as well as to ER 5  through gear ER 1  as shown in  FIGS. 1 and 4 . 
         [0037]    When the oscillating movement transmitted through shaft E 3  rotates clockwise, free wheel RL 1  ( FIGS. 1 and 4 ) located on the outside of gear ER 2  is engaged, while free wheel RL 3  ( FIGS. 1 and 4 ), located on the inside of gear ER 5  is disengaged. Therefore, in this configuration the movement is transmitted only through gear ER 2 , which in turn transmits the movement of gear ER 3  ( FIGS. 1 and 4 ) by means of shaft divider ED 1  ( FIGS. 1 and 4 ). The movement of gear ER 3  is transmitted to gear ER 4  ( FIGS. 1 and 4 ), which spins attached to the satellite holder of the movement rectifier mechanism PSR ( FIGS. 1 and 4 ). The direction of rotation of the satellite holder is transmitted to the rectifier mechanism&#39;s planet and therefore to output shaft E 4  by means of satellites SAR 1 -SAR 3  ( FIGS. 1 and 4 ). In this configuration where shaft E 3  turns clockwise, the crown of the rectifier mechanism CR ( FIGS. 1 and 4 ) remains blocked; in other words, with a null angular speed. Since the tendency of the crown CR in this configuration, for a clockwise rotation of the satellite holder PSR would be to rotate in the opposite direction, free wheel RL 4  ( FIGS. 1 and 4 ), which is located in gear ER 6  ( FIGS. 1 and 4 ), is included in order to cancel its movement in that direction keeping crown CR blocked. 
         [0038]    By the contrary, when the oscillating movement that is transmitted through shaft E 3  is counter-clockwise, free wheel RL 3  located inside gear ER 5  is engaged while free wheel RL 1  located inside gear ER 2  is disengaged. In this configuration, the movement is transmitted only through gear ER 5 , which transmits the movement to gear ER 6  through divider shaft ED 2  ( FIGS. 1 and 4 ). The movement of gear ER 6  is transmitted to the crown CR, which will rotate counter-clockwise. In this configuration where the crown of the rectifier mechanism CR rotates counter-clockwise, the satellite holder would tend to rotate counter-clockwise and therefore, it would force gear ER 4  to rotate in that direction, which rotates attached to the satellite holder PSR. This momentum would cause gear ER 3  to turn clockwise. This momentum would be cancelled by the installation of free wheel RL 2  ( FIGS. 1 and 4 ), which would cause the satellite holder PSR to be blocked. In this configuration, all of the crown&#39;s movement is transmitted to output shaft E 4 , which would turn clockwise. 
         [0039]    This way, when shaft E 3  turns clockwise, the power transmission is carried out as shown in  FIG. 5 , while as shaft E 3  turns counter-clockwise, the power transmission is carried out as shown in  FIG. 6 . This way, the oscillating movement is transformed into a single direction of rotation, taking advantage of the oscillating movements of shaft E 3  in both directions in order to overcome a determined load value at the output shaft of transmission E 4 . 
         [0040]    In subsystem S 3 , which includes the movement rectifier mechanism described herein, the adequate ratios between gears should be maintained in order for the rotation of the output shaft corresponding to both aforementioned configurations to be of equal magnitude for each of them. With this, the torque transmitted by subsystem S 2  at shaft E 3  would be symmetrical for a specific load value at the transmission&#39;s output shaft E 4 . This way, the operation of subsystem S 2 , the inertia regulation mechanism and therefore, of the entire transmission would be as symmetrical and regular as possible.