Lock-up clutch for a hydraulic unit

Abstract

A lock-up clutch having high durability and high reliability of operation is provided in the present invention. Said lock-up clutch comprises a pump impeller connected mechanically with a prime mover, a power shaft, a turbine runner which transmits a driving force given by said pump impeller through a fluid to the power shaft, a stator which forces the circulating flow of a fluid to said pump impeller from said turbine runner, and a one-way clutch which restricts unilaterally the direction of rotation of said stator, wherein the lock-up clutch for a hydraulic unit featuring the provision of a lock-up clutch installed between said pump impeller and said turbine runner to transmit input from the power shaft of said prime mover to said turbine runner by direct, mechanical connection without a medium of a fluid, and of a vibration damper absorbing the torsional vibration from the prime mover or the power shaft when said lock-up clutch is operated, and the installation of said vibration damper in the outside of a circulation flow passage near the inlet caliber of said turbine runner.

We claim:  .[.1. A torque converter consisting of a pump impeller connected mechanically with a power shaft of a prime mover; a turbine runner which transmits a driving force given by said pump impeller through a fluid to said power shaft; a lock-up clutch which is installed between said pump impeller and said turbine runner to transmit directly input from the power shaft of said prime mover to said turbine runner by mechanical connection without an intermediate fluid; a vibration damper which is installed outside of the circulation flow passage of said fluid near the inlet opening of said turbine runner to absorb the torsional vibration from the prime mover or the power shaft when said lock-up clutch is operated; a stator which forces the circulating flow of the fluid to said pump impeller from said turbine runner; and a one-way clutch which restricts unilaterally the direction of rotation of said stator; said lock-up clutch consisting of an annular piston having a power transmission surface which is a friction material engaging a power transmission surface installed on a casing connecting with said pump impeller and movable in an axial direction, a driving plate connected with said annular piston to be driven on the plane crossing at nearly right angles to the axis of the torque converter, a driven plate equipped between said turbine runner and said annular piston, a resistance member placed between said driving plate and said driven plate to give a proper drag resistance to the relative rotational motion of said driving plate and said driven plate, and a plain bearing supporting the reciprocating motion of said annular piston and the relative rotatory motion of said turbine runner and said casing; said vibration damper being between the outside circumference of said driven plate which is fixed to the root of said turbine runner at its inside circumference and having an outside diameter nearly equal to the entrance diameter of said turbine runner and the inside circumference of said driving plate, the outside circumference of said driving plate being 
     
        connected with the outside circumference of said annular piston..]. 2. A torque converter of claim .[.1.]. .Iadd.10.Iaddend., wherein said driven plate .[.consists of.]. .Iadd.comprises .Iaddend.a rear driven plate and a front driven plate .[.which.]..Iadd., wherein said rear driven plate .Iaddend.is attached to the .[.outside.]. .Iadd.external .Iaddend.circumference of said .[.rear.]. .Iadd.front .Iaddend.driven plate, and wherein said vibration damper is supported between said rear 
     
     
        driven plate and said front driven plate. 3. A torque converter of claim .[.1.]. .Iadd.10.Iaddend., wherein said driving plate is connected by plural notches formed at the outside circumference of the flange .Iadd.area .Iaddend.of said annular piston and said driven plate pinches said driving plate in an axial direction to place said vibration damper 
     
     
        between them. 4. A torque converter of claim 2, wherein said driven plate has a window in which said vibration damper is put near the inlet opening of said turbine runner and is formed by using an elastic member easily 
     
     
        flexible in an axial direction. 5. A torque converter of claim 2, wherein said annular piston has a larger movable amount in an axial direction due 
     
     
        to the notch formed on the external circumferential flange area. 6. A torque converter of claim 2, wherein surface hardening treatment .[.was performed.]. at the notches area formed on the external, circumferential 
     
     
        flange area of said annular piston. 7. A torque converter of claim 2, wherein hard facing treatment .[.was performed.]. .Iadd.formed .Iaddend.at the notched area where said driving plate is connected to said annular piston, and at the external, circumferential area of a window for having 
     
     
        said vibration damper. 8. A torque converter of claim 2, wherein said two driven plates have respectively overhangings to restrict motion of said driving plate in the plane .[.paralled.]. .Iadd.paralleled .Iaddend.to the surface of rotation, and also surface hardening treatment .[.was performed for.]. .Iadd.formed at .Iaddend.the surface of said overhanging contacting with said vibration damper .[.or a hardened member was placed between said overhanging and said vibration damper.].. .Iadd. 9. The torque converter of claim 10 wherein the lock-up clutch further comprises a resistance member placed between said driving plate and said driven plate to give a proper drag resistance to the relative rotational motion of said driving plate and said driven plate. .Iadd. 10. A torque converter comprising: a. a pump impeller connected mechanically with a power shaft of a prime mover;   b. a turbine runner which transmits a driving force given by said pump impeller through a fluid to said power shaft;   c. A stator which forces the circulating flow of the fluid to said pump impeller from said turbine runner;   d. A one-way clutch which restricts unilaterally the direction of rotation of said stator;   e. a lock up clutch comprising an annular piston having a flange area and notches on the external circumference of said flange area, said annular piston being movable in an axial direction, capable of engaging aid disengaging with a casing, said casing being connected with said pump impeller, said pump impeller being installed between said casing and said turbine runner to transmit directly input from the power shaft of said prime mover to said turbine runner by mechanical means;   f. a circulation flow passage for said fluid, located near an inlet opening of said turbine runner;   g. a vibration damper installed outside of said circulation flow passage;   h. a friction material installed between said annular piston and said casing, said friction material engaging a power transmission surface;   i. a driving plate connected with said annular piston, said driving plate having notches on its external circumference, said notches crossing the axis of said torque converter at nearly right angles, said driving plate capable of being driven on the plane of said annular piston;   j. a driven plate rotatably connected to said driving plate, positioned between said turbine runner and said annular piston; and   k. means for supporting reciprocal motion of said annular piston and the relative rotary motion of said turbine runner and said casing, wherein said vibration damper engages with a plurality of openings on said driving plate, and is between the outside circumference of said driven plate which is fixed to said turbine runner at its inside circumference and the inside circumference of said driving plate, said driving plate having an outside diameter nearly equal to the entrance diameter of said turbine runner, and the outside circumference of said driving plate being splined with the   
     
     
        outside circumference of said annular piston. .Iaddend..Iadd. 11.  A torque converter of claim 10, wherein said driven plate comprises a rear driven plate and a front driven plate, wherein said front driven plate is attached to the outside circumference of said rear driven plate and wherein said vibrating damper is supported between said rear driven plate and said front driven plate. .Iaddend..Iadd. 12. A torque converter of claim 2, wherein said two driven plates have respectively overhangings to restrict motion of said driving plate in the plane parallel to the surface of rotation, and a hardened member is placed between said overhanging and said vibration damper. .Iaddend.