Abstract:
A hydraulically operated rotary clutch includes a housing, a triangular rotor, an input gear, an eccentric shaft, a main shaft, a shifting piston, and a mechanism to operate the shifting piston. The rotor orbits in an inner elliptical opening of the housing and forms fluid chambers which are filled with a hydraulic fluid. The hydraulic fluid circulates through fluid passages which extend between all fluid chambers when the shifting piston is positioned to allow such fluid circulation, thereby resulting in a disengagement of a drive and driven member. When the shifting piston is driven to restrict the fluid circulation, the driving force is gradually applied to the driven member. A full-scale power flow is reached when the shifting piston is positioned to completely cut off the fluid circulation between the fluid chambers and when the force exerted by the drive member is transmitted through the fluid onto the driven member.

Description:
This application claims benefit to provisional Application 60/114,118 filed Dec. 30, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     A clutch is a friction device used to connect and disconnect a driving force from a driven member. The clutch is designed to provide smooth and positive engagement and disengagement of the engine and manual transmission in engine-powered vehicles. The clutch provides the necessary linkup of the engine and drivetrain that pen-nits power transfer to the driving axles and wheels as well as the necessary halt to power transfer that allows the engine to operate while the transmission does not. Generally speaking, clutch designs can be defined either as a single-plate or multiple-plate design. The single-plate design comprises the driven plate assembly and the pressure plate assembly while the multiple-plate design comprises a plurality of clutch plates and a plurality of friction discs. 
     The clutches in the prior art are relatively complex devices and have to be precisely mounted and always kept properly aligned to prevent slippage, vibration, and noise. Since they have to sustain a significant clamping force, the clutches are also very susceptible to wear and tear. Consequently, any improper driver&#39;s action inevitably results with a clutch damage. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a clutch which will connect and disconnect the driving force between drive and driven members by using a hydraulic fluid to provide a gradual application of force and a rapid halt of power transfer. Consequently, the present invention will eliminate the need to develop friction between relatively hard surfaces and, thereby, enable much smoother engagement of the engine and transmission. It will also minimize the possibility for any wear and tear and eliminate the need for adjusting maintenance. In comparison with the clutches hi the prior art, this design has much simpler physical configuration, lower weight, and smaller volume. 
     One embodiment of the present invention comprises one triangular rotor, an elliptical housing, an eccentric shaft, a main shaft, a power input gear, and a shifting mechanism. The rotor is enclosed within the housing and mounted onto the eccentric shaft which is firmly connected to the input gear. The eccentric shaft is further mounted onto the main shaft while the shifting mechanism is located within a central opening in the main shaft. The shifting mechanism comprises a shifting piston, a retracting spring, and a push rod which is operated by a lever arm connected to a clutch lever. A plurality of lockup balls are also provided within the main shaft and a plurality of fluid passages are provided within the rotor, the eccentric shaft, and the main shaft. Hydraulic fluid is provided around the rotor within the housing and within the fluid passages. 
     According to the process of the present invention, the rotor orbits around the eccentric shaft within the housing and serves as a power input member. The elliptical motion of the rotor alternately creates fluid chambers whose volume either increase or decrease in dependence to the rotor&#39;s positions. Since the rotor&#39;s orbiting permanently increases the volume of some fluid chambers and decreases the volume of other fluid chambers, the hydraulic fluid is permanently displaced from the disappearing fluid chambers and flows in the newly created fluid chambers. The fluid passages are designed so as to provide a fluid communication between all fluid chambers and this communication can be cut only by the shifting piston. Thus, when the piston is positioned to allow the unrestricted flow of fluid, the rotor is able to transfer the fluid from one chamber to another and the power flow is completely cut off. 
     When the piston is moved to restrict the fluid flow between the chambers and passages, the fluid starts being trapped between piston lobes and housing walls. This, in turn, causes the fluid pressure to increase and exert the force onto the housing walls thereby transmitting the driving force to the housing and forcing the housing to rotate in the same direction as the rotor. Since the housing is firmly connected to the main shaft, the driving force is further transmitted to this shaft which extends into the transmission. 
     As the piston moves to block more fluid passages, the fluid circulation is more and more restricted and the fluid pressure is more and more increased. This results in more and more driving force transmitted to the housing which, in turn, increases the housing&#39;s rotating speed. When the piston comes in the position where it completely covers all fluid passages, the fluid circulation is completely cut off and the housing is forced to rotate at the same speed as the rotor. At this instant, a full-scale power flow is established between the drive and driven members and a mechanical lock-up between the main shaft and the eccentric shaft is performed by lock-up balls as described later in the description of the preferred embodiment. 
     As soon as the piston is moved back and it uncovers a section of the fluid passages, the fluid circulation is enabled again and the fluid pressure starts to drop. The smaller fluid pressure acting against the housing&#39;s walls results in smaller driving force transmitted to the housing. Consequently, the housing starts to rotate slower than the rotor and the power flow is cut off when the piston again uncovers all of the fluid passages and enables unrestricted flow of fluid. 
     Yet another embodiment of the present invention comprises one triangular rotor, an elliptical housing, an eccentric shaft, a main shaft, a power input gear, and a shifting mechanism. The rotor is enclosed within the housing and mounted onto the eccentric shaft which is firmly connected to the input gear. The eccentric shaft is further mounted onto the main shaft while a plurality of fluid passages are provided through the housing&#39;s walls. The hydraulic fluid is provided around the rotor within the housing and within the fluid passages. Two fluid valves are provided in the housing&#39;s walls and they intersect the fluid passages. 
     According to the process of the present invention in the second embodiment, the rotor orbits around the eccentric shaft within the housing and serves as a power input member as described above for the first embodiment. The entire chamber forming and fluid displacing process is identical as described above and the fluid passages are designed to provide fluid communication between all fluid chambers. The housing is also finally connected to the main shaft and serves as the output member. The fluid valves are designed to either allow or restrict the flow of fluid through the fluid passages and, thereby, either enable or prevent the flow of fluid between the fluid chambers. 
     When the valves are in their opened positions, they do not influence the flow of fluid which enables the rotor to transfer the fluid from one chamber to another. This results in the unrestricted flow of fluid and the power flow is completely cut off. When the valves start closing the fluid passages, they start restricting the flow of fluid between the chambers and passages and the fluid starts being trapped between piston lobes and housing walls. This, in turn, causes the fluid pressure to increase and exert the force onto the housing walls thereby transmitting the driving force to the housing and forcing the housing to rotate in the same direction as the rotor. 
     Further closing of the valves causes more and more restricted fluid circulation and more and more increased fluid pressure. This results in more and more driving force transmitted to the housing which, in turn, increase the housing&#39; rotating speed. When the valves are completely closed, the fluid circulation is completely cut off and the housing is forced to rotate at the same speed as the rotor thereby providing the full-scale power flow. 
     As soon as the valves start to open again, the fluid circulation is enabled and the fluid pressure starts to drop. As described for the previous embodiment, the smaller fluid pressure acting against the housing&#39;s walls results in smaller driving force transmitted to the housing. Consequently, the housing starts to rotate slower than the rotor and the power flow is cut off when the valves are completely open and the unrestricted flow of fluid is allowed through all of the fluid passages. 
     All features and advantages of the present invention will become apparent from the following brief description of the drawings and the description of the preferred embodiment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is the rear cut-away view of the invention showing the arrangement of all drive, driven, and shifting members and their positions with respect to an adjacent transmission. 
     FIG. 2 is the side cut-away view of the rotor, the elliptical housing, the fluid chambers, the input gear, the eccentric shaft, and the main shaft in the position defined as “zero degrees” of the rotor&#39;s rotation. 
     FIG. 2A is the side cut-away view of the rotor, the elliptical housing, the fluid chambers, the input gear, the eccentric shaft, and the main shaft in the position defined as “90 degrees” of the rotor&#39;s rotation. 
     FIG. 2B is the side cut-away view of the rotor, the elliptical housing, the fluid chambers, the input gear, the eccentric shaft, and the main shaft in the position defined as “180 degrees” of the rotor&#39;s rotation. 
     FIG. 2C is the side cut-away view of the rotor, the elliptical housing, the fluid chambers, the input gear, the eccentric shaft, and the main shaft in the position defined as “270 degrees” of the rotor&#39;s rotation. 
     FIG. 2D is the side cut-away view of the rotor, the elliptical housing, the fluid chambers, the input gear, the eccentric shaft, and the main shaft in the position defined as “360 degrees” of the rotor&#39;s rotation. 
     FIG. 3 is the rear cut-away of the invention showing the position of the shifting assembly when the clutch is completely disengaged. 
     FIG. 3A is the rear cut-away of the invention showing the position of the shifting assembly when the clutch is partially engaged. 
     FIG. 3B is the rear cut-away of the invention showing the position of the shifting assembly when the clutch is completely engaged. 
     FIG. 4 is the perspective view of the rotor. 
     FIG. 4A is the perspective view of the eccentric shaft. 
     FIG. 4B is the cut-away view of the eccentric shaft along the dotted line A—A shown in FIG.  4 A. 
     FIG. 5 is the cut-away view of the elliptical housing. 
     FIG. 6 is the perspective view of the main shaft. 
     FIG. 6A is the perspective view of the shifting piston. 
     FIG. 7 is the perspective view of the input gear. 
     FIG. 8 is the side cut-away view of the rotor, the elliptical housing, the fluid chambers, the input gear, the eccentric shaft, the main shaft, and the fluid valves in the position for the second embodiment wherein the fluid valves are hi their opened positions. 
     FIG. 8A is the side cut-away view of the rotor, the elliptical housing, the fluid chambers, the input gear, the eccentric shaft, the main shaft, and the fluid valves in the position for the second embodiment wherein the fluid valves are in their closed positions. 
     FIG. 9 is the rear cut-away view of the invention for the second embodiment showing the position of the fluid valves when the clutch is completely disengaged. 
     FIG. 9A is the rear cut-away view of the invention for the second embodiment showing the position of the fluid valves when the clutch is completely engaged. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1, the present invention comprises a housing  1 , a rotor  10 , an input gear  3 , an eccentric shaft  30 , a main shaft  2 , a shifting piston  20 , a retracting spring  25 , a plurality of lock-up balls  26 , a contact ball  44 , a main shaft&#39;s cover  11 , a push rod  43 , and a lever arm  42 . As also shown in FIG. 1, the entire invention is located next to a transmission cover/holder  5  wherein the main shaft  2  extends through the cover/holder into a transmission. The main shaft  2  is enclosed by a ball bearing  51  in the cover/holder and transmission drive gears  52  and  53  are also mounted on this shaft  2  as shown in FIG.  1 . On the opposite side the invention is enclosed by a clutch cover  4  which comprises a push rod&#39;s sleeve as shown in FIG.  1 . 
     As shown in FIGS. 2 and 5, the housing  1  of the present invention has an oval internal opening known from the prior art and applied in a rotary (Wankel) engine. As shown in FIG. 2, this opening houses the triangular rotor  10  which orbits within the opening as shown in FIGS. 2A,  2 B,  2 C, and  2 D. The housing has two central openings in its side walls and the eccentric shaft  30  extends through one of these openings as shown in FIG.  1 . The other opening  13 , shown in FIG. 5, is made in a manner which enables the housing to be connected to the end section of the main shaft  2  and ensures that they always rotate together. 
     As shown in FIGS. 1,  2 , and  3 , the rotor  10  is mounted onto the eccentric shaft  30 . A plurality of fluid passages  12  are provided within the rotor  10  and they  12  connect the rotor&#39;s lobes and its central opening as shown in FIG.  4 . The eccentric shaft, shown in FIGS. 1,  2 ,  3 , and  4 A, is mounted onto and rotates around the main shaft  2 . As shown in FIGS. 1,  2 , and  3 , the rotor  10  is mounted onto the eccentric shaft  30  which forces the rotor  10  to orbit around the elliptical opening in the housing  1 . The eccentric shaft also has fluid passages  22  which connect its outer circumference and its central opening as shown in FIG.  4 A. As also shown in FIG. 4A, one end of the eccentric shaft  36  is made to fit into the opening  35  in the input gear  3 , shown in FIG. 7, and provide a firm connection between the eccentric shaft  30  and the input gear  3  which ensures that they always turn together as required by the process of the invention. 
     The main shaft  2  extends through the eccentric shaft  30  and one end of the housing  1  as shown in FIG. 1 and 3. As shown in FIGS. 1,  2 ,  3 , the main shaft  2  has a central opening which houses the shifting piston  20  and the retracting spring  25 . The main shaft  2  also has a plurality of fluid passages  23  which connect its outer circumference and its inner opening as shown in FIG.  6 . As shown in FIGS. 1,  3 , and  6 , this shaft  2  also has a plurality of radial openings  27  which house the contact balls  26 . On the side opposite to the transmission, the main shaft  2  is enclosed by the shaft cover  11  which is also connected to the housing as shown hi FIGS. 1 and 3. 
     The shifting piston  20  is located within the central opening of the main shaft  2  and attached to the retracting spring  25  as shown in FIGS. 1 and 3. As shown in FIGS. 1,  2 , and  3 , the shifting piston  20  has a central opening  21  which is adjacent to the fluid passages  24  which extend from the opening  21  to the outer circumference of the piston  20  as also shown in FIGS. 1,  3 , and  6 A. The piston has a depressed section  28  and raised section  29  as shown in FIG. 6A, wherein the depressed section  28  houses the lock-up balls  26  as shown in FIGS. 3 and 3A, and the raised section  29  displaces the lock-up balls  26  as shown in FIG.  3 B. As shown in FIGS. 1 and 3, the contact ball  44  is provided between the piston  20  and the push rod  43  in order to diminish a friction between these two members  20  and  43  when the piston  20  is rotating and the push rod  43  is stationary. The lever arm  42  is connected to a lever clutch and located next to the push rod  43  as shown in FIG.  1 . 
     The following description of the process of the present invention assumes that the power generated by an engine is exerted onto the input gear  3  which meshes with a gear connected to the engine crankshaft as in the existing motorcycle clutches. However, it is to be understood that the process of the present invention is performed in the identical manner if the power generated by the engine is applied directly from the engine crankshaft/flywheel to the eccentric shaft  30  as in the case of the engines used in four-wheel vehicles. For the purpose of the following description, it is also assumed that the shifting piston  20  is in its ultimate inward position as shown in FIG.  3 . When a rotational force is applied onto the input gear  3 , this gear  3  starts to rotate and forces the eccentric shaft  30  at the same speed. The eccentric shaft  30  further forces the rotor  10  to rotate within the elliptical opening of the housing  1 . 
     As known from the prior art, it takes three revolutions of the eccentric shaft to force the rotor to make one revolution as shown in FIGS. 2A,  2 B,  2 C, and  2 D. As shown in FIG. 2, three fluid chambers  32 ,  33 , and  34  exist around the rotor  10  inside the elliptical opening in the housing  1 . These fluid chambers  32 ,  33 , and  34  are filled with fluid which also fills all of the fluid passages and the opening  21  in the shifting piston. The rotor&#39;s position depicted in FIG. 2 represents the starting position for the following description of the fluid displacement process in the present invention. As depicted in FIGS. 2A,  2 B,  2 C, and  2 D, at the point when the volumes of the fluid chambers  31  and  33  start decreasing (after reaching their maximum volumes), they become the chambers  32  and  34  respectively. 
     During the first 90 degrees of rotor revolution from the position depicted in FIG.2, the rotor  10  displaces the fluid from the fluid chambers  32  and  34  into the fluid chamber  33  and a newly formed fluid chamber  31  as presented by arrows shown in FIG.  2 A. The fluid is displaced from the chambers  32  and  34  which decrease in volume into the chambers  33  and  31  which increase in volume. As shown in FIG. 3, all of the fluid passages  12 ,  22 ,  23 , and  24  are aligned to enable the fluid to flow from the decreasing fluid chambers  32  and  34  into the opening  21  in the piston  20  and flow back into the expanding fluid chambers  31  and  33 . During the next 90 degrees of the rotor&#39;s  10  revolution (from 90 to 180 degrees) the fluid is completely displaced from the fluid chamber  34  which ceases to exist as shown in FIG.  2 B. Also, the fluid is displaced from the decreasing chamber  32  into the increasing chambers  31  and  33  as presented by the arrows shown in FIG.  2 B. 
     As shown in FIG. 2B, after 180 degrees of the rotor&#39;s  10  revolution, the chamber  33  reaches its maximum volume, the chamber  32  has a significantly decreased volume, and chamber  31  has a significantly increased volume. During the next 90 degrees of the rotor&#39;s  10  revolution (from 180 to 270 degrees) the fluid is displaced from the chambers  34  and  32  into the into the chamber  31  and the newly formed chamber  33 . The volumes of the chambers  31  and  33  are increasing and receiving the fluid displaced from the chambers  34  and  32  as shown in FIG.  2 C. During the next 90 degrees of the rotor&#39;s  10  revolution (from 270 to 360 degrees) the fluid is completely displaced from the chamber  32  which disappears as shown in FIG.  2 D. Also, the fluid is displaced from the decreasing chamber  34  into the chamber  33  and the chamber  31  which reaches its maximum volume as shown in FIG.  2 D. 
     In sum, during the above described process, the fluid is simply circulated from the chambers whose volumes are decreasing into the chambers whose volumes are increasing. Since the volumes of the fluid chambers, the fluid passages, and fluid itself are always the same there is no compression of the fluid during this process. Consequently, there is no pressure exerted onto the housing&#39;s  1  walls and the housing  1  remains stationary. It is to be understood that all fluid passages  12 ,  22 ,  23 , and  24  are made in a manner as shown in FIGS. 3,  4 ,  4 A,  6 , and  6 A which does not allow the flow of fluid between any of the fluid passages which are positioned parallel to each other, i.e. the fluid can flow only between passages which are vertically adjacent to each other. 
     When the clutch lever is depressed, it allows the lever arm  42 , the push rod  43 , and the contact ball  44  to move outwards and enables the force of the retracting spring  25  to push the shifting piston  20  in the same direction. As the shifting piston  20  slides outwards, its fluid passages  24  start to disalign with the fluid passages  23  in the main shaft. This disalignment results in a lesser area available for fluid flow between the fluid passages  24  and  23  which further results in more restricted fluid flow and increased fluid pressure within the diminishing fluid chambers. As the fluid pressure is raised, it starts acting against the housing&#39;s  1  walls and, consequently, starts forcing the housing  1  to rotate in the same direction as the rotor  10 . As a result, the power flow is gradually applied and transmitted onto the main shaft  2  which is firmly connected to the housing  1 . 
     As the contact area between the fluid passages  24  and  23  decreases, the force required to displace the fluid increases which further causes the fluid pressure to increase. The increased fluid pressure exerts more force on the housing&#39;s  1  walls and forces the housing  1  to rotate faster and faster. When the force of the retracting spring  25  displaces the piston  20  to the point where its fluid passages  24  do not have any contact with the fluid passages  23  in the main shaft  2 , the fluid circulation is completely cut off and the fluid is trapped in the fluid chambers. This, in turn, causes the housing  1  to rotate at the same speed as the rotor  10  and establish the unrestricted full-scale power flow to the main shaft  20  which further transmits the driving force to the transmission drive gears. 
     During the last stage of the piston&#39;s  10  displacement the lock-up balls  26  are pushed outwards by the piston&#39;s raised section  29 . As shown hi FIG. 4B, the inner opening of the eccentric shaft  30  has a plurality of notches  37  wherein the lock-up balls are inserted by the piston&#39;s raised section  29  as soon as the housing&#39;s  1  rotating speed reaches the rotor&#39;s  10  rotating speed. When the piston  20  comes to its ultimate outward position as shown in FIG. 3B, the rotor  10  and the housing  1  are locked by the fluid trapped in the fluid chambers while the eccentric shaft  30  and the main shaft  2  are joined by the lock-up balls  26  which are intended to support the lock-up performed by the fluid and compensate for possible fluid leaks within the housing  1 . 
     When the lever clutch is pressed, it forces the lever arm  42  to exert the force onto the push rod  43  which over the contact ball  44  forces the shifting piston  20  to move inwards and press against the retracting spring  25 . As shown in FIG. 3A, the lock-up balls are pushed back into their openings  27  in the main shaft  2  and the depressed section  28  in the piston  20 . As soon as the fluid passages  24  in the piston  20  start overlapping with the fluid passages  23  in the main shaft  2 , the fluid circulation is enabled again and the fluid pressure in the fluid chambers starts to decrease. The decreased fluid pressure starts exerting less force on the housing&#39;s  1  walls and causes the housing&#39;s  1  rotating speed to drop below the rotor&#39;s  10  rotating speed. 
     As the piston  20  is pushed inwards, it results in more and more contact area between the fluid passages  23  and  24  and causes the fluid pressure to rapidly decrease. The decrease of the fluid pressure results in lesser force exerted on the housing&#39;s walls and, consequently, slower rotation of the housing  1  and the main shaft  2 . The process of this gradual disengagement lasts until the piston  20  reaches the position where its fluid passages  24  completely align with the fluid passages  23  in the main shaft  2  as shown in FIG.  3 . At this instant, the unrestricted fluid circulation is allowed again and the power flow between the engine and the transmission is completely cut off. 
     As shown in FIGS. 8,  8 A,  9 , and  9 A, the second embodiment of the present invention comprises the housing  1 , the rotor  10 , the input gear  3 , the eccentric shaft  30 , the main shaft  2 , two rotary fluid valves  15  and a connecting bolt  11 . The fluid passages  14  are made through the housing&#39;s  1  walls and they connect all of the fluid chambers  31 ,  32 ,  33 , and  34  as shown in FIGS. 8 and 8A. The rotary fluid valves  15  are also provided within the housing&#39;s  1  walls as also shown in FIGS. 8 and 8A and their function is to restrict the flow of fluid between all of the fluid chambers. As shown in FIGS. 9 and 9A, the eccentric shaft  30  is firmly connected to the input gear  3  and the housing  1  is firmly connected to the main shaft  2  both through their contact areas and by the connecting bolt  11 . 
     According to the process of the present invention for the second embodiment, the formation of the fluid chambers  31 ,  32 ,  33 , and  34  as the result of the rotor&#39;s  10  rotation and the fluid displacement between these chambers is identical to the above described process for the first embodiment of the present invention as shown in FIGS. 2A,  2 B,  2 C and  2 D. It is also assumed that the power flow from the engine and to the transmission is identical as described above. Unlike in the case of the first embodiment, the fluid circulation between the fluid chambers in the second embodiment of the present invention is performed through the fluid passages  14  shown in FIGS. 8 and 8A. 
     When the fluid valves  15  are in positions as shown in FIGS. 8 and 9, the fluid is allowed to freely circulate between the fluid chambers  31 ,  32 ,  33 , and  34  and the power flow is completely cut off When the valves  15  are turned, they start closing the fluid passages  14  and thereby restricting the flow of fluid between the fluid chambers which cause the fluid pressure to rise and act against the housing&#39;s  1  walls. The pressure exerted on the housing walls forces the housing  1  to rotate in the same direction as the rotor  10 . The housing&#39;s  1  rotating speed gradually increases and becomes equal to the rotor&#39;s  10  rotating speed at the point when the valves  15  are completely closed and the fluid is trapped in the fluid chambers as shown in FIGS. 8A and 9A. At this point, the unrestricted full-scale power flow is established between the engine and the transmission. 
     When the fluid valves  15  are rotated back, they open the fluid connections in the fluid passages  14  and allow the flow of fluid between the chambers. This, in turn, results in the decreased fluid pressure which allows the housing  1  to rotate slower than the rotor  10 . Gradual opening of the valves  15  results in gradual disconnection of the power flow until the point when the valves  15  are completely open and the fluid circulation is completely unrestricted as shown in FIG.  8 . At this instant, the power flow between the engine and the transmission is completely cut off again. 
     It is to be understood that the present invention has been described in relation to the particular embodiments, herein chosen for the purpose of illustration, and that the claims are intended to cover all changes and modifications, apparent to those skilled in the art, which do not constitute departure from the scope and spirit of the invention.