Swash plate-type motor

Abstract

On a near-bottom inner surface of a tilt piston cylinder hole, only a limited part that contacts an end of a tilt piston when the tilt piston is tilted by a pressing force from a swash plate is laser-hardened along the circumferential direction of the tilt piston cylinder hole (i.e., a hardened part is formed). In the tilt piston cylinder hole, parts other than a near-opening inner surface and the near-bottom inner surface are not laser-hardened.

1 . A swash plate-type motor comprising:
 an output shaft provided to be rotatable with respect to a main body casing;   a cylinder block engaged with the output shaft;   pistons provided in cylinder holes formed in the cylinder block, respectively;   a swash plate configured to contact the pistons;   a tilt piston configured to change a tilt angle of the swash plate by pressing the swash plate; and   a tilt piston cylinder hole formed in the main body casing to slidably support the tilt piston,   on a near-bottom inner surface of the tilt piston cylinder hole, a limited part that contacts an end of the tilt piston when the tilt piston is tilted by a pressing force from the swash plate being laser-hardened, and   the tilt piston cylinder hole being not laser-hardened except at a near-opening inner surface and the near-bottom inner surface.   
     
     
         2 . The swash plate-type motor according to  claim 1 , wherein,
 the near-bottom inner surface is laser-hardened in a circumferential direction, and a degree of laser-hardening is gradually increased toward the limited part.   
     
     
         3 . The swash plate-type motor according to  claim 2 , wherein,
 on the near-bottom inner surface, an opposing part opposing the limited part is not laser hardened, whereas parts other than the opposing part are continuously laser hardened.   
     
     
         4 . The swash plate-type motor according to  claim 2 , wherein,
 an entirety of a circumference of the near-bottom inner surface is laser-hardened.   
     
     
         5 . The swash plate-type motor according to  claim 3 , wherein,
 on the near-bottom inner surface, the degree of laser hardening is gradually increased toward parts which are at equal phase differences in a circumferential direction and include the limited part.   
     
     
         6 . The swash plate-type motor according to  claim 1 , wherein,
 on the near-bottom inner surface, two lines are formed along an axial direction only at the limited part by laser hardening.   
     
     
         7 . The swash plate-type motor according to  claim 1 , wherein,
 on the near-bottom inner surface, two lines are formed along a circumferential direction only at the limited part by laser hardening.   
     
     
         8 . The swash plate-type motor according to  claim 1 , wherein,
 an entirety of the circumference of the near-opening inner surface is further laser-hardened.   
     
     
         9 . The swash plate-type motor according to any one of  claim 1 , wherein,
 on the near-opening inner surface, a part which is diagonally opposite to the limited part, which contacts the end of the tilt piston, is further laser-hardened.   
     
     
         10 . The swash plate-type motor according to  claim 9 , wherein,
 on the near-opening inner surface, two lines are formed by laser hardening only at parts each contacting the end of the tilt piston, along an axial direction.   
     
     
         11 . The swash plate-type motor according to  claim 9 , wherein,
 on the near-opening inner surface, two lines are formed by laser hardening only at parts each contacting the end of the tilt piston, along a circumferential direction.   
     
     
         12 . The swash plate-type motor according to  claim 1 , wherein,
 an apex of a part swelled by the laser hardening is processed to be a flat surface.