Oil cooling and filtering system of automatic transmission

Abstract

An oil cooling and filtering system of a transmission is described which comprises first and second oil passages formed in a given portion of a housing of the transmission. The given portion has an outer surface exposed to the outside of the housing. The first oil passage is fed with a compressed lubricating oil from an oil compressing means and the second oil passage is led to moving parts of the transmission which are to be lubricated. An oil cooler is connected to the outer surface of the given portion. The oil cooler includes a water flow passage and an oil flow passage which are isolated from each other. The oil flow passage has an inlet opening connected to the first oil passage and an outlet opening connected to the second oil passage. An oil filter is installed in at least one one of the first and second oil passages for filtering the lubricating oil flowing in the oil passage. With this arrangement, the oil cooler can be compact in size and simple in construction.

1 . An oil cooling and filtering system of a transmission, comprising: 
 first and second oil passages formed in a given portion of a housing of the transmission, the given portion having an outer surface exposed to the outside of the housing, the first oil passage being fed with a compressed lubricating oil from an oil compressing means and the second oil passage being led to moving parts of the transmission which are to be lubricated;    an oil cooler connected to the outer surface of the given portion, the oil cooler including a water flow passage and an oil flow passage which are isolated from each other, the oil flow passage having an inlet opening connected to the first oil passage and an outlet opening connected to the second oil passage; and    an oil filter installed in at least one of the first and second oil passages for filtering the lubricating oil flowing in the oil passage.    
     
     
         2 . An oil cooling and filtering system as claimed in  claim 1 , in which the oil filter is installed in the first oil passage for filtering the lubricating oil flowing in the first oil passage toward the oil cooler.  
     
     
         3 . An oil cooling and filtering system as claimed in  claim 2 , in which the first oil passage is formed with an enlarged portion in which the oil filter is installed.  
     
     
         4 . An oil cooling and filtering system as claimed in  claim 3 , in which the enlarged portion of the first oil passage is formed in the given portion in such a manner that the enlarged portion terminates at the outer surface of the given portion of the transmission housing.  
     
     
         5 . An oil cooling and filtering system as claimed in  claim 4 , in which the enlarged portion of the first oil passage is formed with a filter seat portion on which an end of the oil filter is seated.  
     
     
         6 . An oil cooling and filtering system as claimed in  claim 5 , further comprising a seal member which is put between the filter seat portion and the end of the oil filter.  
     
     
         7 . An oil cooling and filtering system as claimed in  claim 3 , in which the enlarged portion of the first oil passage is a cylindrical bore and the oil filter is cylindrical in shape.  
     
     
         8 . An oil cooling and filtering system as claimed in  claim 7 , in which a diameter of the cylindrical oil filter is smaller than a diameter of the cylindrical bore.  
     
     
         9 . An oil cooling and filtering system as claimed in  claim 1 , in which the oil cooler comprises: 
 a circular depressed base plate;    a circular cover plate; and    a plurality of circular depressed element plates which are the same in shape, the circulate depressed element plates being stacked together between the circular depressed base plate and the circular cover plate in such a manner as to form the water flow passage and the oil flow passage.    
     
     
         10 . An oil cooling and filtering system as claimed in  claim 9 , in which each of the circular depressed element plates comprises: 
 a depressed circular major portion;    an annular flange extending along a periphery of the depressed circular major portion;    two circular simple openings formed in a circular flat base part of the depressed circular major portion; and    two collared circular openings formed also in the circular flat base part of the depressed circular major portion,    wherein every neighboring two of the stacked circular depressed element plates are so arranged that the collared openings of one circular depressed element plate are mated with the simple openings of the other circular depressed element plate thereby to define between the two circular depressed element plates a thin space that forms part of either one of the water flow passage and the oil flow passage.    
     
     
         11 . An oil cooling and filtering system as claimed in  claim 10 , in which the two circular simple openings are located at diametrically opposed positions of the circular flat base part of the depressed circular major portion, and in which the two collared openings are located at diametrically opposed positions of the circular flat base part of the depressed circular major portion.  
     
     
         12 . An oil cooling and filtering system as claimed in  claim 11 , in which the two circular simple openings and the two collared circular openings are arranged so that an imaginary line passing through centers of the two circular simple openings and another imaginary line passing through centers of the two collared circular openings meet at right angles.  
     
     
         13 . An oil cooling and filtering system of an automatic transmission comprising: 
 first and second oil passages formed in a given portion of a housing of the transmission, the given portion having a flat outer surface exposed to the outside of the housing, the first oil passage terminating at the flat outer surface and being fed with a compressed lubricating oil from an oil pump, the second oil passage terminating at the flat outer surface and being led to moving parts of the transmission which are to be lubricated;    an oil cooler detachably connected to the flat outer surface of the given portion, the oil cooler including a water flow passage and an oil flow passage which are isolated from each other, the oil flow passage having an inlet opening connected to the first oil passage and an outlet opening connected to the second oil passage;    a cylindrical bore formed in the given portion of the housing and merged with the first oil passage, the cylindrical bore terminating at the flat outer surface of the given portion; and    a cylindrical oil filter installed in the cylindrical bore of the given portion for filtering the lubricating oil flowing in the first oil passage toward the oil cooler.