Pump unit with integrated piston pump and electric motor
View Patent ↗An automotive hydraulic actuating system for actuating a movable vehicle part, like a roof part or a wheel suspension. The actuating system comprises a pump unit. The pump unit comprises a piston pump which has a pump rotor and an electric motor which has a motor rotor. The pump rotor and motor rotor are incorporated into a single common rotor. The rotor is a one piece item. The rotor is positioned inside a pump chamber around a pump stator of the piston pump. The pump stator provides a full support to the common rotor. Advantageously, without a separate motor stator, the pump unit has a more compact configuration. Additionally, the pump unit has an improved dynamic performance which contributes to a silent and reliable operation at a high rotational speed.
1. A pump unit for pressurising a hydraulic actuating system, wherein the pump unit comprises a pump housing including a pump chamber for housing a piston pump, and wherein the pump unit further comprises an electric motor for driving the piston pump, wherein the electric motor comprises:
a motor rotor, wherein the motor rotor comprises a longitudinal motor rotor body including several magnets at an outer surface, wherein the motor rotor body defines an axial axis;
a field coil which is positioned opposite the magnets of the motor rotor body for rotationally driving the motor rotor body;
wherein the piston pump comprises:
a pump stator which is stationary inside the pump chamber, which pump stator has a longitudinal stator body which includes at least two channels serving respectively as an inlet or outlet channel;
a pump rotor positioned around the pump stator body, which pump rotor has a pump rotor body which is driveable in a rotational direction about the axial axis, wherein the pump rotor body includes several cylinder holes for each receiving a piston which is slidable with respect to the pump rotor body in a radial direction;
a ring positioned around the pump rotor body, wherein the ring is eccentrically positioned at an eccentricity with respect to the pump rotor body to provide a pump capacity;
wherein the motor rotor and the pump rotor are incorporated into a common rotor such that the motor rotor body and the pump rotor body are formed as a one piece item with the motor rotor and the pump rotor located on opposite axial ends and wherein the pump stator is fixed to the pump housing adjacent to the pump rotor as a cantilever which extends axially through the pump rotor body to a position beyond the cylinder holes such that the common rotor is fully supported by the cantilevered pump stator.
2. The pump unit according to claim 1 , wherein the pump stator extends through the common rotor over at least half a length of the common rotor.
3. The pump unit according to claim 1 , wherein the common rotor is manufactured from a solid part.
4. The pump unit according to claim 1 , wherein the magnets of the motor rotor are positioned at an outer circumferential motor rotor surface.
5. The pump unit according to claim 1 , wherein the common rotor has a motor rotor recess which is open at a motor rotor end face, wherein the motor rotor recess has an inner circumferential surface and an inner bottom surface, wherein the magnets are positioned at the inner circumferential surface or at the inner bottom surface.
6. The pump unit according to claim 1 , wherein the magnets of the motor rotor are positioned at a motor rotor end face of the common rotor.
7. The pump unit according to claim 1 , wherein the field coil is positioned outside the pump chamber of the pump housing.
8. The pump unit according to claim 1 , wherein the pump unit further comprises a control unit for controlling the pump capacity, wherein the control unit is connectable to a closure of the pump housing for closing a pump chamber, wherein the control unit and the closure form a subassembly which is mountable as a module to the pump housing.
9. The pump unit according to claim 8 , wherein the module of the control unit and closure further comprises at least one field coil of the electric motor.
10. The pump unit according to claim 1 , wherein a reservoir is formed by the pump chamber in the pump housing.
11. The pump unit according to claim 1 , wherein the pump stator extends into the motor rotor body to an axial position of the magnets.