Pump

Abstract

The present invention is directed to providing a pump capable of achieving improvement of a discharge efficiency. A pump configured to suck and discharge fluid includes a housing, a driving shaft rotatably supported on the housing, and a pump element contained in the housing and configured to be rotated by the driving shaft. The housing contains therein an intake passage into which the fluid delivered from outside the housing is introduced, an intake port configured to guide the fluid from the intake passage to the pump element, a discharge port into which the fluid pressurized by the pump element is introduced, and a discharge passage configured to discharge the fluid delivered from the discharge port to outside the housing. The discharge passage includes a first passage including a beginning portion connected to the discharge port and a termination portion. The first passage extends as far as the termination portion around one straight line. The discharge passage further includes a second passage connected to the termination portion of the first passage and opened to outside the housing. A shape of the first passage in cross section taken along a direction perpendicular to the straight line changes continuously from the beginning portion to the termination portion.

1 . A pump configured to suck and discharge fluid, the pump comprising:
 a housing;   a driving shaft rotatably supported on the housing; and   a pump element contained in the housing and configured to be rotated by the driving shaft,   wherein the housing contains therein   an intake passage to which the fluid is introduced from outside the housing,   an intake port configured to guide the fluid from the intake passage to the pump element,   a discharge port to which the fluid is introduced after being pressurized by the pump element, and   a discharge passage configured to discharge the fluid delivered from the discharge port to outside the housing,   wherein the discharge passage includes   a first passage including a beginning portion connected to the discharge port and a termination portion, the first passage extending as far as the termination portion around one straight line, and   a second passage connected to the termination portion of the first passage, the second passage being opened to outside the housing, and   wherein a shape of the first passage in cross section taken along a direction perpendicular to the straight line continuously changes from the beginning portion to the termination portion.   
     
     
         2 . The pump according to  claim 1 , wherein, a cross-sectional shape of a connection portion between the discharge port and the beginning portion changes continuously between the discharge port and the beginning portion. 
     
     
         3 . The pump according to  claim 1 , wherein the straight line extends along an axis of the driving shaft. 
     
     
         4 . The pump according to  claim 1 , wherein the housing includes
 a housing main body including a recessed portion, the recessed portion being a bottomed cylindrical recessed portion extending around an axis of the driving shaft, the recessed portion containing the pump element, and   a cover closing an opening of the recessed portion, and   wherein the discharge port is opened on a bottom surface of the recessed portion in an axial direction of the driving shaft.   
     
     
         5 . The pump according to  claim 4 , wherein the discharge port extends along an axis of the driving shaft. 
     
     
         6 . The pump according to  claim 1 , wherein a dimension of the discharge port in a rotational direction of the driving shaft is larger than a dimension of the discharge port in a radial direction of the driving shaft, and
 wherein a dimension of the first passage in the rotational direction of the driving shaft is larger than a dimension of the first passage in the radial direction of the driving shaft.   
     
     
         7 . The pump according to  claim 6 , wherein the first passage is disposed on a front side in the rotational direction of the driving shaft with respect to the discharge port. 
     
     
         8 . The pump according to  claim 6 , wherein at least a part of a wall on an outer side in the radial direction of the driving shaft, among walls forming an inner periphery of the discharge port, is located on the outer side in the radial direction of the driving shaft with respect to a circular arc, the circular arc being centered at the axis of the driving shaft, the circular arc passing through an end on the outer side in the radial direction of the driving shaft in the beginning portion of the discharge port in the rotational direction of the driving shaft. 
     
     
         9 . The pump according to  claim 1 , wherein the housing includes a plate-like flattened portion,
 wherein a part of the first passage and the second passage are located inside the flattened portion,   wherein the second passage is opened on a surface of the flattened portion on one side, and   wherein a fixation portion for fixing a member connected to an opening of the second passage is provided at the flattened portion.   
     
     
         10 . The pump according to  claim 1 , wherein the second passage is opened to outside the housing at a position away from the driving shaft in the axial direction of the driving shaft. 
     
     
         11 . The pump according to  claim 1 , wherein a second end portion of the driving shaft on an opposite side from a first end portion of the driving shaft that is located close to the opening of the second passage in the axial direction of the driving shaft protrudes from the housing, and is connected to a member for driving the driving shaft. 
     
     
         12 . The pump according to  claim 1 , wherein the second passage extends along one straight line. 
     
     
         13 . The pump according to  claim 1 , wherein an area of the cross section of the first passage reduces as the first passage extends from the beginning portion to the termination portion. 
     
     
         14 . The pump according to  claim 1 , wherein the second passage extends in a direction different from a direction in which the first passage extends,
 wherein an area of an opening of the second passage at the termination portion of the first passage is equal to or smaller than an area of the first passage in cross section taken at a portion of the opening of the second passage at the termination portion of the first passage that is located closest to the beginning portion of the first passage, and is equal to or larger than an area of the first passage in cross section taken at a portion of the opening of the second passage at the termination portion of the first passage that is located farthest from the beginning portion of the first passage.   
     
     
         15 . The pump according to  claim 1 , wherein the housing includes
 a housing main body including a recessed portion containing the pump element,   a cover closing an opening of the recessed portion,   a first fixation portion for fixing the cover to the housing main body, and   a second fixation portion for fixing the housing to another member at a different position from the first fixation portion.   
     
     
         16 . A pump configured to pressurize and discharge sucked fluid, the pump comprising:
 a housing;   a shaft rotatably supported on the housing; and   a pump element contained in the housing and coupled with the shaft,   wherein the housing contains therein   an intake passage for introducing the fluid from outside the housing to the pump element, and   a discharge passage for discharging the fluid pressurized by the pump element to outside the housing, and   wherein the discharge passage includes   a first passage extending around one straight line and including a beginning portion on one side where the pump element is located, and a termination portion, the first passage being shaped in such a manner that an area of a cross section thereof perpendicular to the straight line gradually reduces as the first passage extends from the beginning portion toward the termination portion, and   a second passage connected to the termination portion of the first passage and opened to outside the housing.   
     
     
         17 . The pump according to  claim 16 , wherein the straight line extends along an axis of the shaft, and
 wherein a dimension of the first passage in a rotational direction of the shaft is larger than a dimension of the first passage in a radial direction of the shaft.   
     
     
         18 . A method for manufacturing a pump, comprising:
 forming a housing main body integrally by casting, the housing main body including   a recessed portion capable of rotationally containing a pump element,   an intake port opened on the recessed portion,   a discharge port opened on the recessed portion and extending along a rotational axis of the pump element, the discharge port having a flattened shape elongated in a rotational direction of the pump element in cross section perpendicular to the rotational axis of the pump element,   a first passage connected to the discharge port and extending along the rotational axis of the pump element, the first passage having a flattened shape elongated in the rotational direction of the pump element in cross section perpendicular to the rotational axis of the pump element, and   a second passage connected to the first passage and extending linearly to be opened on an outer surface of the housing;   mounting the pump element into the recessed portion; and   closing an opening of the recessed portion with a cover.