Pump for conveying a liquid, particularly an exhaust gas cleaning additive
A pump for conveying liquid includes a pump housing with an inlet and an outlet. An eccentric mounted at the housing rotates about an axis relative to the housing. A deformable element is disposed between the housing and the eccentric. A delivery duct from the inlet to the outlet is formed by the deformable element and a circumferential housing surface. The deformable element is pressed in sections against the housing by the eccentric to form a displaceable seal of the delivery duct and a closed pump volume in the delivery duct, which can be displaced along the delivery duct from the inlet to the outlet by a movement of the eccentric to convey liquid. A channel cross-section of the delivery duct is limited by the circumferential surface, a set-back duct surface of the deformable element and a contact seal between the circumferential surface and the deformable element.
1. A pump for delivering a liquid, the pump comprising:
at least one pump housing having at least one inlet, at least one outlet and a circumferential surface, said pump housing having a pump axis defining an axial direction of the pump;
an eccentric disposed in said pump housing and rotatable relative to said pump housing about said pump axis;
a deformable element disposed between said pump housing and said eccentric, said deformable element having a set-back duct surface and said deformable element defining at least one contact seal between said circumferential surface and said deformable element, said set-back duct surface being set back from a contact position of said at least one contact seal against said circumferential surface;
a delivery duct extending from said at least one inlet to said at least one outlet, said delivery duct being formed by said deformable element and said circumferential surface;
said deformable element being pressed in sections against said pump housing by said eccentric to form at least one displaceable seal of said delivery duct and at least one closed pump volume in said delivery duct;
said at least one displaceable seal and said at least one closed pump volume being displaceable along said delivery duct from said at least one inlet to said at least one outlet by a movement of said eccentric for a delivery of the liquid; and
said delivery duct having at least one duct cross section delimited by said circumferential surface, by said set-back duct surface and by said at least one contact seal;
said delivery duct having two sides; and
said circumferential surface continuing in said axial direction of the pump towards said two sides of said delivery duct beyond said at least one contact seal of said deformable element.
2. The pump according to claim 1 , which further comprises:
at least one counter bracket;
said deformable element having at least one edge region;
said circumferential surface of said pump housing and said at least one counter bracket forming at least one receptacle; and
said at least one edge region of said deformable element being received in said at least one receptacle.
3. The pump according to claim 1 , which further comprises:
at least one abutment surface situated towards sides of said deformable element;
said deformable element having at least one edge region bearing against said at least one abutment surface.
4. A motor vehicle, comprising:
an internal combustion engine;
an exhaust-gas treatment device for purification of exhaust gases of said internal combustion engine;
a tank for storing a liquid additive for exhaust-gas purification;
an injector for supplying the liquid additive to said exhaust-gas treatment device; and
a pump according to claim 1 configured to deliver the liquid additive from said tank to said injector.
5. A pump for delivering a liquid, the pump comprising:
at least one pump housing having at least one inlet, at least one outlet, a pump axis, and a circumferential surface;
an eccentric disposed in said pump housing and rotatable relative to said pump housing about said pump axis;
a deformable element disposed between said pump housing and said eccentric, said deformable element having a set-back duct surface and said deformable element defining at least one contact seal between said circumferential surface and said deformable element, said set-back duct surface being set back from a contact position of said at least one contact seal against said circumferential surface, said deformable element including two sides each having a respective edge region, and said deformable element having rigid centering rings each encircling a respective one of said edge regions on a respective one of said sides of said deformable element in an axial direction;
a delivery duct extending from said at least one inlet to said at least one outlet, said delivery duct being formed by said deformable element and said circumferential surface;
said deformable element being pressed in sections against said pump housing by said eccentric to form at least one displaceable seal of said delivery duct and at least one closed pump volume in said delivery duct;
said at least one displaceable seal and said at least one closed pump volume being displaceable along said delivery duct from said at least one inlet to said at least one outlet by a movement of said eccentric for a delivery of the liquid; and
said delivery duct having at least one duct cross section delimited by said circumferential surface, by said set-back duct surface and by said at least one contact seal.
6. The pump according to claim 5 , wherein said centering rings are mounted to be movable in a radial direction.
7. A pump for delivering a liquid, the pump comprising:
at least one pump housing having at least one inlet, at least one outlet and a circumferential surface, said pump housing having a pump axis defining an axial direction of the pump;
an eccentric disposed in said pump housing and rotatable relative to said pump housing about said pump axis;
a deformable element disposed between said pump housing and said eccentric, said deformable element having a set-back duct surface and said deformable element defining at least one contact seal between said circumferential surface and said deformable element, said deformable element including at least one edge region having at least one encircling thickened section forming said at least one contact seal;
a delivery duct extending from said at least one inlet to said at least one outlet, said delivery duct being formed by said deformable element and said circumferential surface;
said deformable element being pressed in sections against said pump housing by said eccentric to form at least one displaceable seal of said delivery duct and at least one closed pump volume in said delivery duct;
said at least one displaceable seal and said at least one closed pump volume being displaceable along said delivery duct from said at least one inlet to said at least one outlet by a movement of said eccentric for a delivery of the liquid; and
said delivery duct having at least one duct cross section delimited by said circumferential surface, by said set-back duct surface and by said at least one contact seal;
said delivery duct having two sides; and
said circumferential surface continuing in said axial direction of the pump towards said two sides of said delivery duct beyond said at least one contact seal of said deformable element.