Hydraulic pump for excavator and excavator comprising the same

Abstract

A hydraulic pump for an excavator, which comprises a housing having a supporting wall extending therein; a pair of rotary hydraulic cylinders provided in the housing, each of the rotary hydraulic cylinders being provided with a piston which is movable reciprocatingly in the rotary hydraulic cylinder; and a pair of spindles disposed parallel to the rotary hydraulic cylinders, the spindles being connected with each other via a coupler and driving the rotary hydraulic cylinders to rotate about their respective central axes, each of the rotary hydraulic cylinders comprising a swash plate for receiving and guiding the piston, and the swash plate being stationary relative to the respective spindle, wherein the supporting wall comprises a mounting hole, and the coupler is supported in the mounting hole by means of a sliding bearing.

1 . A hydraulic pump for an excavator comprising:
 a housing having a supporting wall extending therein;   a pair of rotary hydraulic cylinders provided in the housing, each of the rotary hydraulic cylinders being provided with a respective piston which is movable reciprocatingly in the rotary hydraulic cylinder; and   a pair of spindles disposed parallel to the rotary hydraulic cylinders, the spindles being connected with each other via a coupler and driving the rotary hydraulic cylinders to rotate about respective central axes, each of the rotary hydraulic cylinders comprising a swash plate for receiving and guiding the respective piston, and the swash plate being stationary relative to the respective spindle,   wherein the supporting wall comprises a mounting hole, and the coupler is supported in the mounting hole by means of a sliding bearing.   
     
     
         2 . The hydraulic pump according to  claim 1 , further comprising an adapting bushing, wherein the sliding bearing is mounted in the mounting hole via the adapting bushing so that the adapting bushing is located between an outer circumferential surface of the sliding bearing and an inner surface of the mounting hole. 
     
     
         3 . The hydraulic pump according to  claim 2 , wherein a circumferential flange extends out radially from an outer circumferential surface of the adapting bushing near an end of the adapting bushing which is adjacent to a surface of the supporting wall, and the circumferential flange is configured for contacting with the supporting wall. 
     
     
         4 . The hydraulic pump according to  claim 3 , wherein the sliding bearing is configured as a pair of sliding bearings axially spaced from each other. 
     
     
         5 . The hydraulic pump according to  claim 4 , wherein the adapting bushing is configured as a pair of adapting bushings axially spaced from each other. 
     
     
         6 . The hydraulic pump according to  claim 5 , wherein the supporting wall is formed with an oil guiding hole, and the oil guiding hole is aligned with and communicated with an axial gap between the adapting bushings. 
     
     
         7 . The hydraulic pump according to  claim 6 , wherein the oil guiding hole is configured for receiving oil leaked in running of the rotary hydraulic cylinders, so that the leaked oil can pass by the sliding bearing and flow out via the oil guiding hole after cooling the bearings. 
     
     
         8 . The hydraulic pump according to  claim 2 , wherein at least one of the sliding bearing and the adapting bushing is provided with chamfers at opposite ends. 
     
     
         9 . The hydraulic pump according to  claim 2 , wherein the adapting bushing is made of an alloy steel material, and the sliding bearing is made of a powder metallurgy material. 
     
     
         10 . The hydraulic pump according to  claim 1 , wherein a pair of spherical splines are mounted between the coupler and the spindles. 
     
     
         11 . The hydraulic pump according to  claim 7 , wherein at least one of the sliding bearing and the adapting bushing is provided with chamfers at opposite ends. 
     
     
         12 . The hydraulic pump according to any  claim 11 , wherein the adapting bushing is made of an alloy steel material, and the sliding bearing is made of a powder metallurgy material. 
     
     
         13 . The hydraulic pump according to  claim 12 , wherein a pair of spherical splines are mounted between the coupler and the spindles. 
     
     
         14 . An excavator comprising a hydraulic pump according to  claim 1 .