Multiple plate clutch device

Abstract

A multiple plate clutch device is provided to conserve space. In a reverse hydraulic brake device 7, a plurality of teeth 35 is formed next to one another in a circumferential direction in an inner peripheral surface portion 31 of a transmission case 21. A plurality of first brake plates 24 includes engagement teeth 41, 42. The engagement teeth 41, 42 engage the plurality of teeth 35 on the inner peripheral surface portion 31 such that the plurality of first brake plates 24 is axially movable and non-rotatable relative to the inner peripheral surface 31. A plurality of second brake plates 25 is disposed to alternate axially with the plurality of first brake plates 24. A piston 22 pushes the plates 24 and 25. Return springs 28 are disposed within deep grooves 37 that are between the teeth 35 and the inner peripheral surface portion 31. The return springs 28 urge the first plate 29 that is closest the piston 22 towards the piston 22.

What is clamed is:  
     
         1 . A multiple plate clutch device comprising: 
 a first member having a plurality of teeth aligned around a circumference thereof;    a second member being disposed to face said first member in the radial direction;    a plurality of first plates having engaging teeth that engage with the plurality of teeth of said first member, said plurality of first plates being non-rotatable and axially movable relative to said first member;    a plurality of second plates being disposed alternately with respect to said plurality of first plates in an axial direction and non-rotatably and axially movably engaging with said second member relative to said second member;    a piston being configured to press said plurality of first plates and said plurality second plates together; and    a return spring being disposed inside a groove between said teeth of said first member, said return spring being configured to push one of said plurality of first plates being closest to said piston toward said piston.    
     
     
         2 . The multiple plate clutch device according to  claim 1 , wherein said return spring is a flat spring.  
     
     
         3 . The multiple plate clutch device according to  claim 2 , wherein said return spring is disposed between an engaging tooth of said one of said plurality of first plates being closest to said piston and an engaging tooth of one of said plurality of first plates being farthest from said piston.  
     
     
         4 . The multiple plate clutch device according to  claim 3 , wherein an end of said return springy is held in said engaging tooth of said one of said plurality of first plates being closest to said piston.  
     
     
         5 . A multiple plate clutch device according to  claim 4 , wherein said one end of said return spring is fixedly connected to said engaging tooth of said one of said plurality of first plates being closest to said piston in such a manner that said return spring cannot fall out.  
     
     
         6 . The multiple plate clutch device according to  claim 5 , wherein a slit is provided in said engaging tooth of said one of said plurality of first plates being closest to said piston and said return spring has a claw that is connected to said slit provided in said engaging teeth of said one of said plurality of first plates being closest to said piston.  
     
     
         7 . The multiple plate clutch device according to  claim 6 , wherein said return spring has a flat section that abuts an axially facing surface of said engaging tooth of said one of said plurality of first plates being closest to said piston.  
     
     
         8 . The multiple plate clutch device according to  claim 7 , wherein said return spring has a curved part that contacts said engaging tooth of said one said first plate being farthest from said piston.  
     
     
         9 . The multiple plate clutch device according to  claim 8 , wherein said return spring has a projection whose movement in the radial direction is restricted by said engaging tooth of said first plate that is farthest from said piston.  
     
     
         10 . A torque transmission system comprising: 
 a torque converter input shaft;    a continuously variable transmission output shaft; and    a forward-reverse rotation device being configured to transmit torque from said input shaft to said output shaft, said forward-reverse rotation device comprising, 
 a forward-reverse switching device having a forward hydraulic clutch device being configured to receive torque from said input shaft, and  
 a planetary gearset being configured to switch a power transmission path by said forward-reverse switching device,  
 said planetary gearset being configured to be controlled by a multiple plate clutch device, said multiple plate clutch device comprising, 
 a first member having a plurality of teeth aligned around a circumference thereof,  
 a second member being disposed to face said first member in the radial direction,  
 a plurality of first plates having engaging teeth that engage with the plurality of teeth of said first member, said plurality of first plates being non-rotatable and axially movable relative to said first member,  
 a plurality of second plates being disposed alternately with respect to said plurality of first plates in an axial direction and non-rotatably and axially movably engaging with said second member relative to said second member,  
 a piston being configured to press said plurality of first plates and said plurality second plates together, and  
 a return spring being disposed inside a groove between said teeth of said first member, said return spring being configured to push one of said plurality of first plates being closest to said piston toward said piston.  
 
   
     
     
         11 . The torque transmission system according to  claim 10 , wherein said return spring is a flat spring.  
     
     
         12 . The torque transmission system according to  claim 11 , wherein said return spring is disposed between an engaging tooth of said one of said plurality of first plates being closest to said piston and an engaging tooth of one of said plurality of first plates being farthest from said piston.  
     
     
         13 . The torque transmission system according to  claim 12 , wherein an end of said return spring is held in said engaging tooth of said one of said plurality of first plates being closest to said piston.  
     
     
         14 . A torque transmission system according to  claim 13 , wherein said one end of said return spring is fixedly connected to said engaging tooth of said one of said plurality of first plates being closest to said piston in such a manner that said return spring cannot fall out.  
     
     
         15 . The torque transmission system according to  claim 14 , wherein a slit is provided in said engaging tooth of said one of said plurality of first plates being closest to said piston and said return spring has a claw that is connected to said slit provided in said engaging teeth of said one of said plurality of first plates being closest to said piston.  
     
     
         16 . The torque transmission system according to  claim 15 , wherein said return spring has a flat section that abuts an axially facing surface of said engaging tooth of said one of said plurality of first plates being closest to said piston.  
     
     
         17 . The torque transmission system according to  claim 16 , wherein said return spring has a curved part that contacts said engaging tooth of said one said first plate being farthest from said piston.  
     
     
         18 . The torque transmission system according to  claim 17 , wherein said return spring has a projection whose movement in the radial direction is restricted by said engaging, tooth of said first plate that is farthest from said piston.  
     
     
         19 . The torque transmission system according to  claim 11 , wherein an elastic member is arranged between said piston and said one of said plurality of first plates being closest to said piston.  
     
     
         20 . The torque transmission system according to  claim 14 , wherein said engaging tooth of said one of said plurality of first plates being closest to said piston is configured to have an aperture and said one end of said return spring is configured to have a first projection that is inserted into said aperture in a first direction, said one end of said return spring is configured to have a second to have a second projection that extends in a second direction, said first direction and said second direction are substantially perpendicular.