Automatic transmission pump apparatus or pump apparatus

Abstract

The present invention provides a pump apparatus capable of preventing or reducing deterioration of efficiency of a pump. The pump apparatus includes a venturi portion provided on the way along a discharge passage. The venturi portion includes a small diameter portion having a smaller inner diameter than an inner diameter of the discharge passage from a discharge port to the venturi portion and an inner diameter gradually-increasing portion formed in such a manner that an inner diameter thereof gradually increases from the small diameter portion toward a downstream side of the discharge passage. The pump apparatus further includes a control valve configured to receive introduction of hydraulic fluid on an upstream side of the venturi portion and hydraulic fluid in the venturi portion. The control valve is configured to control a flow amount of hydraulic fluid to be supplied into an automatic transmission by switching a flow passage of the hydraulic fluid based on a differential pressure between a pressure on the upstream side of the venturi portion and a pressure in the venturi portion ( 50 ).

1 . An automatic transmission pump apparatus for supplying hydraulic fluid to an automatic transmission of a vehicle, the automatic transmission pump apparatus comprising:
 a pump housing including a pump element containing portion;   a driving shaft pivotally supported on the pump housing;   a pump element provided in the pump element containing portion and configured to be rotationally driven by the driving shaft, the pump element forming a plurality of pump chambers around the driving shaft;   an intake port formed at the pump housing and opened to an intake region where a volume of a pump chamber increases according to a rotation of the driving shaft among the plurality of pump chambers;   a discharge port formed at the pump housing and opened to a discharge region where the volume of the pump chamber reduces according to the rotation of the driving shaft among the plurality of pump chambers;   a discharge passage connected to the discharge port; and   a venturi portion provided on the way along the discharge passage, the venturi portion including a small diameter portion having a smaller inner diameter than an inner diameter of the discharge passage from the discharge port to the venturi portion and an inner diameter gradually-increasing portion formed in such a manner that an inner diameter thereof gradually increases from the small diameter portion toward a downstream side of the discharge passage; and   a control valve configured to receive introduction of hydraulic fluid on an upstream side of the venturi portion and hydraulic fluid in the venturi portion, the control valve including a spool valve body controlled based on a differential pressure between the hydraulic fluid on the upstream side of the venturi portion and the hydraulic fluid in the venturi portion, the control valve being configured to control a flow amount of the hydraulic fluid to be supplied into the automatic transmission at least by switching a flow passage of the hydraulic fluid introduced from the upstream side of the venturi portion.   
     
     
         2 . The automatic transmission pump apparatus according to  claim 1 , wherein the pump housing includes a pump housing main body including the pump element containing portion, and a venturi forming block that is a separate member from the pump housing main body and is joined to the pump housing main body,
 wherein the venturi portion is formed at the venturi forming block, and   wherein the venturi forming block is jointed to the pump housing main body after the venturi portion is formed.   
     
     
         3 . The automatic transmission pump apparatus according to  claim 2 , wherein the pump housing main body is made from a metallic material,
 wherein the venturi forming block is made from a resin material, and   wherein the venturi portion is formed by molding.   
     
     
         4 . The automatic transmission pump apparatus according to  claim 2 , wherein the pump housing main body is made from a metallic material,
 wherein the venturi forming block is made from a sintered material, and   wherein the venturi portion is formed with use of a mold in a powder compacting process.   
     
     
         5 . The automatic transmission pump apparatus according to  claim 2 , wherein the small diameter portion of the venturi portion is formed so as to be opened on an outer surface of the venturi forming block. 
     
     
         6 . The automatic transmission pump apparatus according to  claim 1 , wherein the venturi portion is provided in such a manner that a longitudinal direction of the venturi portion and a direction of a, rotational axis of the driving shaft extend generally perpendicularly to each other. 
     
     
         7 . The automatic transmission pump apparatus according to  claim 6 , wherein the venturi portion is provided at a position that does not overlap the intake port on a cross section perpendicular to the rotational axis of the driving shaft but overlaps the intake port in the direction of the rotational axis of the driving shaft. 
     
     
         8 . The automatic transmission pump apparatus according to  claim 6 , wherein the venturi portion is provided in such a manner that a longitudinal direction of the venturi portion and a longitudinal direction of the control valve extend generally in parallel with each other. 
     
     
         9 . The automatic transmission pump apparatus according to  claim 8 , wherein the control valve includes a high pressure chamber into which a pressure on the upstream side of the venturi portion is introduced and an intermediate pressure chamber into which a pressure in the venturi portion is introduced, and
 wherein the venturi portion is disposed in such a manner that the upstream side of the venturi portion faces the high pressure chamber of the control valve.   
     
     
         10 . The automatic transmission pump apparatus according to  claim 1 , wherein the venturi portion is provided in such a manner that a longitudinal direction of the venturi portion and a direction of a rotational axis of the driving shaft extend generally in parallel with each other. 
     
     
         11 . The automatic transmission pump apparatus according to  claim 10 , wherein the venturi portion is provided at a position that is located on a radially outer side with respect to the pump element containing portion in a radial direction of the rotational axis of the driving shaft, and overlaps the pump element containing portion in the direction of the rotational axis of the driving shaft. 
     
     
         12 . The automatic transmission pump apparatus according to  claim 1 , wherein the venturi portion includes an opening provided on the small diameter portion or one side of the inner diameter gradually-increasing portion that is closer to the small diameter portion in a longitudinal direction of the venturi portion, the opening being configured to supply the hydraulic fluid in the venturi portion into the control valve, and
 wherein the opening includes a plurality of openings provided in a direction around an axis line along the longitudinal direction of the venturi portion.   
     
     
         13 . The automatic transmission pump apparatus according to  claim 1 , wherein the venturi portion is formed in such a manner that a narrower angle sandwiched between inner walls of the inner diameter gradually-increasing portion is 60 degrees or smaller. 
     
     
         14 . The automatic transmission pump apparatus according to  claim 13 , wherein, when it is defined that L represents a length of a longitudinal direction of the inner diameter gradually-increasing portion when the inner diameter gradually-increasing portion is formed as far as an inner diameter thereof reaches a same diameter as an inner diameter of the discharge passage from the discharge port to the venturi portion while the narrower angle sandwiched between inner walls of the inner diameter gradually-increasing portion is kept constant, the inner diameter gradually-increasing portion includes a front portion formed as far as a position where the length in the longitudinal direction is 65% of the length L or longer while the narrower angle sandwiched between the inner walls of the inner diameter gradually-increasing portion is kept constant at 60 degrees or smaller, and a rear portion provided on a downstream side of the front portion and formed in such a manner that the narrower angle exceeds 60 degrees. 
     
     
         15 . The automatic transmission pump apparatus according to  claim 1 , wherein the control valve or the venturi portion is provided at a housing that is a separate member from the pump housing. 
     
     
         16 . The automatic transmission pump apparatus according to  claim 1 , wherein the venturi portion includes an opening provided at the small diameter portion and configured to supply the hydraulic fluid in the venturi portion to the control valve. 
     
     
         17 . The automatic transmission pump apparatus according to  claim 1 , wherein the pump element is a pump element for a fixed displacement pump in which a discharge amount per rotation of the driving shaft is constant, and
 wherein the control valve switches the flow passage of the hydraulic fluid so as to return the hydraulic fluid introduced from the upstream side of the venturi portion to an intake port side.   
     
     
         18 . The automatic transmission pump apparatus according to  claim 1 , wherein the pump element includes
 a rotor including a plurality of slits in a circumferential direction,   a vane provided so as to be projectable and retractable from and into each of the slits of the rotor,   a cam ring provided displaceably in the pump element containing portion and annularly formed, the cam ring forming the plurality of pump chambers together with the rotor and the vane, and   a first fluid pressure chamber and a second fluid pressure chamber that are a pair of spaces formed between the cam ring and the pump element containing portion, the first fluid pressure chamber and the second fluid pressure chamber being respectively provided on one side where a volume reduces and an opposite side where the volume increases when an eccentric amount of the cam ring with respect to the rotor increases,   wherein the pump element is a pump element of a variable displacement pump in which a discharge amount per rotation of the driving shaft is variably controlled, and   wherein the control valve switches the flow passage of the hydraulic fluid so as to introduce the hydraulic fluid introduced from the upstream side of the venturi portion into the first fluid pressure chamber.   
     
     
         19 . A pump apparatus comprising:
 a pump housing including a pump element containing portion;   a driving shaft pivotally supported on the pump housing;   a pump element provided in the pump element containing portion and configured to be rotationally driven by the driving shaft, the pump element forming a plurality of pump chambers around the driving shaft;   an intake port formed at the pump housing and opened to an intake region where a volume of a pump chamber increases according to a rotation of the driving shaft among the plurality of pump chambers;   a discharge port formed at the pump housing and opened to a discharge region where the volume of the pump chamber reduces according to the rotation of the driving shaft among the plurality of pump chambers;   a discharge passage connected to the discharge port; and   a venturi portion provided on the way along the discharge passage, the venturi portion including a small diameter portion having a smaller inner diameter than an inner diameter of the discharge passage from the discharge port to the venturi portion and an inner diameter gradually-increasing portion formed in such a manner that an inner diameter thereof gradually increases from the small diameter portion toward a downstream side of the discharge passage; and   a control valve configured to receive introduction of hydraulic fluid on an upstream side of the venturi portion and hydraulic fluid in the small diameter portion, the control valve including a spool valve body controlled based on a differential pressure between the hydraulic fluid on the upstream side of the venturi portion and the hydraulic fluid in the small diameter portion, the control valve being configured to control a flow amount of the hydraulic fluid to be supplied into an apparatus mounted on a vehicle at least by switching a flow passage of the hydraulic fluid introduced from the upstream side of the venturi portion.