Power transmission mechanism and compressor

Abstract

A power transmission mechanism transmits power of an external drive source to a rotary shaft. The transmission mechanism has a first rotor rotated by the external power source. A second rotor is connected to the rotary shaft. The second rotor is coaxial with the first rotor and coupled to the first rotor transmit power to the first rotor. A disconnecting body disconnects power transmission from the first rotor to the second rotor when an excessive transmission torque is generated between the rotors. A dynamic damper is provided in at least one of the rotors. The dynamic damper has a weight that swings like a pendulum. The axis of the pendulum motion of the weight is separated by a predetermined distance from and is substantially parallel to the rotation axis of the corresponding rotor.

1 . A power transmission mechanism for transmitting power of an external drive source to a rotary shaft, the transmission mechanism comprising: 
 a first rotor rotated by the external power source;    a second rotor connected to the rotary shaft, wherein the second rotor is coaxial with the first rotor and coupled to the first rotor to transmit power to the first rotor;    a disconnecting body, which disconnects power transmission from the first rotor to the second rotor when an excessive transmission torque is generated between the rotors; and    a dynamic damper provided in at least one of the rotors, wherein the dynamic damper has a weight that swings like a pendulum, wherein the axis of the pendulum motion of the weight is separated by a predetermined distance from and is substantially parallel to the rotation axis of the corresponding rotor.    
     
     
         2 . The power transmission mechanism according to  claim 1 , wherein the disconnecting body is a breakable member located in a power transmission path between the rotors, wherein the breakable member breaks when the excessive transmission torque is generated.  
     
     
         3 . The power transmission mechanism according to  claim 2 , wherein the breakable member is made of one of sintered metal and low-carbon steel.  
     
     
         4 . The power transmission mechanism according to  claim 2 , wherein the first rotor is rotatably supported by a support member, which rotatably supports the rotary shaft, and wherein the breakable member is a pin and is connected to at least one of the rotors via an elastic member fitted about the breakable member.  
     
     
         5 . The power transmission mechanism according to  claim 1 , wherein the disconnecting body has a coupling member, which couples the rotors to each other to permit power to be transmitted between the rotors and engages with at least one of the rotors, wherein, when the coupling member is disengaged from the one of the rotors, the power transmission between the rotors is disconnected.  
     
     
         6 . The power transmission mechanism according to  claim 5 , wherein the coupling member is a leaf spring.  
     
     
         7 . The power transmission mechanism according to  claim 1 , wherein a shock absorbing member is located in the power transmission path between the rotors.  
     
     
         8 . The power transmission mechanism according to  claim 7 , wherein the second rotor is coupled to the rotary shaft and integrally rotates with the rotary shaft, wherein the first rotor is rotatably supported by a support member, which rotatably supports the rotary shaft, and wherein the shock absorbing member is an elastic member.  
     
     
         9 . The power transmission mechanism according to  claim 1 , wherein the weight is one of a plurality of weights, wherein the weights are arranged or constructed to suppress a plurality of order components in rotational vibration generated in the corresponding rotor.  
     
     
         10 . A compressor comprising: 
 a rotary shaft;    a compression mechanism driven by rotation of the rotary shaft to compress fluid;    a first rotor supported by the rotary shaft to rotate integrally with the rotary shaft;    a second rotor fixed to the rotary shaft and for rotating integrally with the rotary shaft, wherein the second rotor is substantially coaxial with the first rotor and is rotated by the external drive source;    a disconnecting body located between the rotors, wherein the disconnecting body disconnects power transmission from the first rotor to the second rotor when an excessive transmission torque is generated between the rotors; and    a dynamic damper provided in at least one of the rotors, wherein the dynamic damper has a weight that swings like a pendulum, wherein the axis of the pendulum motion of the weight is separated by a predetermined distance from and is substantially parallel to the rotation axis of the corresponding rotor.    
     
     
         11 . The compressor according to  claim 10 , wherein the disconnecting body is a breakable member located in a power transmission path between the rotors, wherein the breakable member breaks when the excessive transmission torque is generated.  
     
     
         12 . The power transmission mechanism according to  claim 11 , wherein the breakable member is made of one of sintered metal and low-carbon steel.  
     
     
         13 . The power transmission mechanism according to  claim 10 , wherein a shock absorbing member is located in the power transmission path between the rotors.  
     
     
         14 . The power transmission mechanism according to  claim 13 , wherein the first rotor is rotatably supported by a support member, which rotatably supports the rotary shaft, and wherein the shock absorbing member is an elastic member.  
     
     
         15 . The power transmission mechanism according to  claim 10 , wherein the weight is one of a plurality of weights, wherein the weights are arranged or constructed to suppress a plurality of order components in rotational vibration generated in the corresponding rotor.  
     
     
         16 . The compressor according to  claim 10  further comprising a piston type compression mechanism, which has piston accommodated in a cylinder bore, and wherein the compression mechanism compresses refrigerant in accordance with reciprocation of the piston.  
     
     
         17 . The compressor according to  claim 11 , wherein the piston is one a plurality of pistons, and the cylinder bore is one of a plurality of cylinder bores, each of which accommodates one of the pistons, and wherein the number of the cylinder bores is three, four, five, six or seven.  
     
     
         18 . The compressor according to  claim 16 , wherein the number of the cylinder bores is three.  
     
     
         19 . The compressor according to  claim 18 , wherein the compression mechanism is driven by the rotary shaft, and wherein the displacement per rotation of the rotary shaft is varied.