Inline piston pump

Abstract

The present invention relates to an inline piston pump, comprising a driveshaft for driving the inline piston pump; at least two pistons which are operatively connected to the driveshaft and are disposed along a driveshaft axis and are in each case disposed so as to be movable in a reciprocating manner in a piston chamber; a suction connector for supplying a fluid to be pumped; wherein a suction valve is disposed in at least one, preferably in each, piston chamber in order to fluidically separate a suction duct for the inflow of fluid from the piston chamber during a compression movement of the associated piston. The pump is characterized in that a suction throttle valve which is conceived for varying a volumetric flow of a fluid to be pumped between the suction chamber and the suction duct is provided between the suction connector and the suction duct which in fluidic terms is connected directly to the at least one valve.

1 . An inline piston pump, comprising:
 a driveshaft for driving the inline piston pump;   at least two pistons which are operatively connected to the driveshaft and are disposed along a driveshaft axis and are in each case disposed so as to be movable in a reciprocating manner in a piston chamber;   a suction connector for supplying a fluid to be pumped; wherein   a suction valve is disposed in at least one, preferably in each, piston chamber in order to fluidically separate a suction duct for an inflow of fluid from the piston chamber during a compression movement of an associated piston;   wherein   an installation which is conceived for varying a volumetric flow of a fluid to be pumped between the suction chamber and the suction duct is provided between the suction connector and the suction duct which in fluidic terms is connected directly to at least one suction valve.   
     
     
         2 . The inline piston pump as claimed in  claim 1 , wherein a hydraulic installation is a valve which has a displaceable valve piston which is disposed in such a manner that a longitudinal axis thereof is preferably disposed so as to be parallel to the driveshaft axis, wherein the valve is preferably embodied as a suction throttle valve. 
     
     
         3 . The inline piston pump as claimed in  claim 2 , wherein the suction throttle valve has the displaceable valve piston for varying a degree of opening of a connection between the suction connector and the suction duct. 
     
     
         4 . The inline piston pump as claimed in preceding  claim 3 , wherein the displaceable valve piston has a flow region which, for varying a degree of opening of the connection between the suction connector and the suction duct, in a longitudinal direction of the piston is configured by a portion which is reduced in terms of a diameter thereof, wherein the flow region can preferably be designed as an annular space. 
     
     
         5 . The inline piston pump as claimed in  claim 4 , wherein the valve piston is a differential piston, thus possesses at least two regions which differ in terms of the diameters thereof, wherein the flow region is disposed in one of said regions, wherein the at least two regions which differ in terms of the diameters thereof are preferably configured in two parts. 
     
     
         6 . The inline piston pump as claimed in  claim 5 , wherein the region provided with the flow region has a leakage duct which runs in a displacement direction of the piston so that fluid emanating from a control bore or high-pressure bore, respectively, can be discharged to a suction side. 
     
     
         7 . The inline piston pump as claimed in  claim 4 , wherein the valve piston in the longitudinal direction thereof is supported on at least one restoring spring, and the valve piston has an operating face to which fluid can be supplied by way of a control bore or high-pressure bore, respectively, which is correspondingly placed in a corresponding housing part, wherein the operating face is directed in such a manner that a fluid pressure prevailing thereon exerts a force which is directed counter to a restoring force of the at least one restoring spring, wherein the operating face is preferably situated on the corresponding end side of the piston, and/or the valve piston when undershooting a pressure level in the control bore or high-pressure bore, respectively, below a specific threshold value is held in a first terminal detent position. 
     
     
         8 . The inline piston pump as claimed in  claim 7 , wherein the end of the restoring spring that faces away from the valve piston is supported on a closure element which is incorporated in a piston bore, and/or the closure element serves as a terminal detent for a displacement movement of the piston that is diametrically opposed to a first-mentioned terminal detent, wherein the closure element is preferably embodied as a closure screw. 
     
     
         9 . The inline piston pump as claimed in  claim 7 , wherein the suction throttle valve is equipped with at least one further compression spring which acts on the valve piston only once the restoring spring by virtue of a certain variation of the position of the piston is compressed by a certain length, and/or the suction throttle valve is equipped with at least one further compression spring which no longer acts on the valve piston only once the restoring spring by virtue of a certain variation of the position of the piston is compressed by a certain length. 
     
     
         10 . The inline piston pump as claimed in  claim 7 , wherein the piston is able to be impinged by a force which emanates from a servomotor, a proportional magnet and/or a supplied control pressure, for example, and is directed counter to the force that prevails on account of the pressure level supplied to the valve piston by way of the control bore or high-pressure bore, respectively. 
     
     
         11 . The inline piston pump as claimed in  claim 6 , wherein the control bore or high-pressure bore, respectively, is fluidically connected to a high-pressure output of the inline piston pump, wherein this preferably takes place by way of a hydraulic unit which from the high-pressure output of the inline piston pump can generate a reduced pressure level which is preferably able to be predefined by a remote action. 
     
     
         12 . The inline piston pump as claimed in  claim 1 , wherein the driveshaft is a camshaft having single cams or multiple cams so as to be embodied as a crankshaft or an eccentric shaft. 
     
     
         13 . The inline piston pump as claimed in  claim 11 , wherein the driveshaft is driven by way of a primary drive which is preferably embodied as an internal combustion engine and/or an electric machine, and/or a torque of the driveshaft that is provided by the primary drive is preferably supplied by way of a gearbox. 
     
     
         14 . The inline piston pump as claimed in  claim 11 , wherein a rotating speed signal which fixedly correlated with the rotating speed of the driveshaft is supplied back to an open-loop and/or closed-loop control installation, and/or a pressure signal which is fixedly correlated with a high-pressure level of the inline piston pump, in particular the pressure level at a high-pressure duct or at the high-pressure output, is supplied back to an open-loop or closed-loop control installation, and/or a pressure signal which is fixedly correlated with the pressure level at a suction region, in particular the pressure level at the suction connector or in the suction duct, is supplied back to an open-loop or closed-loop control installation. 
     
     
         15 . The inline piston pump as claimed in  claim 14 , wherein flows of a fluid to be pumped that are generated by a respective piston are not completely unified with one another downstream but are guided out of the inline piston pump by way of at least two separate high-pressure outputs. 
     
     
         16 . The inline piston pump as claimed in  claim 1 , wherein the at least two pistonshave dissimilar diameters. 
     
     
         17 . The inline piston pump as claimed in  claim 15 , wherein the flow of a fluid to be pumped that is generated by a respective piston is implemented downstream by selectively providing at least one duct separator which is inserted into the high-pressure duct. 
     
     
         18 . The inline piston pump as claimed in  claim 15 , wherein a switch valve which selectively unifies or does not unify the at least two separate high-pressure outputs from the inline piston pump and discharges the volumetric flow generated on account of a unification to a collective output is provided. 
     
     
         19 . A method for open-loop or closed-loop controlling at least one volumetric output flow of an inline piston pump as claimed in  claim 1 , wherein:
 the volumetric output flow is performed as a function of a rotating speed of the driveshaft in an absence of an installation, or at a constant setting of the installation at which an ideally low pressure loss exists along a suction path, that is to say from the suction connector to the suction duct.   
     
     
         20 . The method for open-loop or closed-loop controlling a volumetric output flow of an inline piston pump as claimed in  claim 1 , wherein:
 the volumetric output flow is variable as a function of a rotating speed of the driveshaft and/or of a degree of opening of the installation and/or by way of a switch valve.   
     
     
         21 . The method for open-loop or closed-loop controlling the output and/or the torque of an inline piston pump as claimed in  claim 13 , wherein the installation can be set by way of an actuator which receives an actuation signal from a control apparatus, and the control apparatus preferably receives at least one further input signal from another unit which supplies a mechanical output to the inline piston pump and/or receives a hydraulic output from the inline piston pump, and the control apparatus is supplied at least one operating variable of the inline piston pump.