Pump with detection of absolute angle of rotation

Abstract

The invention relates to an orbital pump for pumping a fluid, wherein the pump comprises at least one pump control system, a motor that can be controlled by the pump control system, a rotor shaft (10) for fluid transport, and a rotor sensor for detecting an absolute angle of rotation of the rotor shaft (40), the rotor sensor is connected to the pump control system and designed to transmit the angle of rotation of the rotor shaft (40) to the pump control system, and the pump control system is designed to rotationally control the rotor shaft (40) by means of the motor until the rotor shaft (40) is in a pre-determined angle of rotation position.

Claims

1. A pump for pumping a fluid, wherein the pump comprises at least one pump control system, a motor that can be controlled by the pump control system, a rotor shaft (40) for fluid transport, and a rotor sensor for detecting an absolute angle of rotation of the rotor shaft (40), the rotor sensor is connected to the pump control system and designed to transmit the angle of rotation of the rotor shaft (40) to the pump control system, and the pump control system is designed to rotationally control the rotor shaft (40) by means of the motor until the rotor shaft (40) is in a pre-determined angle of rotation position based on the angle of rotation of the rotor shaft (40) transmitted from the rotor sensor; wherein between a fluid inlet (11) into the pump and a fluid outlet (12) from the pump, a leakage flow channel (15) is formed in a cavity in the pump and the leakage flow channel (15) is closed when the rotor shaft (40) is in the pre-determined angle of rotation position to inhibit leakage flow of the fluid between the fluid inlet (11) and the fluid outlet (12).

2. The pump of claim 1, wherein the pump comprises a pump housing (10), an elastically deformable pump ring (20), and an eccentric (30) driven by or formed by the rotor shaft (40), the pump ring (20) is arranged in the pump housing (10) and is spaced from the pump housing (10) in its radial direction at least in sections, the pump ring (20) comprises a central opening in which the eccentric (30) is arranged, and a deformed section (21) of the pump ring (20) is deformable in a radial direction by a rotation of the eccentric (30) in a circumferential direction (U) of the pump ring (20) and is pressable against the pump housing (10), wherein an angle of rotation of the deformed section (21) of the pump ring (20) corresponds to the angle of rotation of the rotor shaft (40).

3. The pump of claim 2, wherein the rotor sensor is arranged on the rotor shaft (40), on the eccentric (30) or on the pump ring (20) and detects the respective angle of rotation.

4. The pump of claim 1, wherein the motor is an electric motor with a rotor, the rotor is directly connected to the rotor shaft (40), and the angle of rotation of the rotor shaft (40) corresponds to an angle of rotation of the rotor.

5. The pump of claim 1, wherein the motor is an electric motor with a rotor, the rotor is indirectly connected to the rotor shaft (40), and the angle of rotation of the rotor shaft (40) can be determined from an angle of rotation of the rotor.

6. The pump of claim 4, wherein the rotor sensor is arranged on the rotor and identifies the angle of rotation of the rotor.

7. The pump of claim 1, wherein the rotor sensor is an encoder or a resolver detecting the angle of rotation of the rotor shaft (40).

8. The pump of claim 1, wherein the rotor sensor is an absolute-value transducer.

9. The pump of claim 1, wherein the rotor sensor is an incremental transducer, and the pump comprises a reference sensor detecting the position of the rotor shaft (40) in the pre-determined angle of rotation position for referencing the rotor sensor.

10. The pump of claim 2, wherein the pump ring (20) comprises, when viewed in the circumferential direction (U), first and second deformation sections (24, 25), the pump ring (20) is designed to be more elastically deformable in the first deformation section (24) than in its second deformation section (25), and wherein the pre-determined angle of rotation position is established in the first deformation section (24).

11. A method for controlling the pump of claim 1, wherein a volumetric fluid flow transported through the pump from the fluid inlet (11) to the fluid outlet (12) of the pump is calculated from a plurality of angles of rotation of the rotor shaft (40) detected by the rotor sensor in a pre-determined time interval, and the motor driving the rotor shaft (40) is controlled depending on a volumetric fluid flow to be transported according to a pre-determined motor characteristic that controls rotation of the rotor shaft (40) to achieve a volumetric fluid flow to be transported that corresponds to the calculated volumetric fluid flow that was transported through the pump.

12. The method of claim 11, wherein the motor is controlled to stop and position the rotor shaft (40) at the pre-determined angle of rotation position when the volumetric flow to be transported is zero.

13. The pump of claim 5, wherein the rotor sensor is arranged on the rotor and identifies the angle of rotation of the rotor.

14. The pump of claim 1, wherein the pump control system is designed to control metering by the pump using the angle of rotation of the rotor shaft (40) transmitted from the rotor sensor to transport fluid from the cavity in the pump whereby the rotor shaft (40) is rotated by a predetermined angle relative to the pre-determined angle of rotation position that closes the leakage flow channel (15) that is less than a full revolution.

Description

(1) Other advantageous developments of the invention are characterised in the dependent claims or are further set forth below by reference to the FIGURE. In the FIGURE:

(2) FIG. 1 shows an orbital pump with a cut-away pump housing in a top view of the pump ring.

(3) The pump schematically depicted in FIG. 1 is provided with a rotor sensor and a pump control system even though they are not recognisable in the FIGURE.

(4) The pump housing 10 is shown in a section orthogonal to a longitudinal axis such that the cavity 14 located in the pump housing 10 is visible with the components arranged therein. As part of the pump housing 10, a fluid inlet 11 with a channel extends into the cavity 14 and a fluid outlet 12 with a channel extends from the cavity 14. An elastically deformable pump ring 20 is arranged in the cavity 14. The rotor shaft 40 shown in section passes through the centre of the cavity 14, which is cylinder-shaped or designed to be round in the sectional view, along an axis of rotation not depicted and extending along its axial direction orthogonal to the page. An eccentric 30 is arranged on the rotor shaft 40 and acts on or presses against the elastically deformable pump ring 20 by means of a bearing ring 32 between the pump ring 20 and the eccentric 30. The bearing ring 32 is a needle bearing, for example, formed from needle elements and embodied as a radial bearing whereby the eccentric 30 may rotate therein in the pump ring 20, deforming the pump ring 20 without directly abutting the deformable pump ring 20. With the rotor shaft 40 at its depicted angle of rotation, the eccentric 30 presses the pump ring 20 in the eccentric direction 31, causing the elastically deformable pump ring 20 to be deformed in its radial direction located in the page such that the section 21 of the pump ring 20 abuts the pump housing 10 in the radial direction. By means of a rotation of the eccentric in the circumferential direction U, the deformed section 21 of the pump ring 20 moves in the circumferential direction U about the axis of rotation, such that the section 21 rotates in the circumferential direction without the pump ring 20 rotating at the same time. The pump ring 20 is spaced from the pump housing 10 in sections and only abuts the pump housing 10 in the radial direction in the rotating section 21 and in a sealing section 22. By rotating the rotating section 21 of the pump ring 20 and spacing the pump ring 20 from the pump housing 10 in the radial direction, two chambers varying in size by means of the rotation of the rotating section 21 are determined in the cavity 14 by the pump housing 10 and the pump ring 20. A fluid is drawn into a first chamber connected to the fluid inlet 11 through the fluid inlet 11 into the cavity 14 or the first chamber increasing in size, and a fluid is expelled from the second chamber connected to the fluid outlet 12 from the cavity 14 or from the second chamber decreasing in size.

(5) Between a fluid inlet 11 into the pump and a fluid outlet 12 from the pump, a leakage flow channel 15 is determined in the pump. An advantageous development of the invention provides that the leakage flow channel 15 is closed with the rotor shaft 40 in the pre-determined angle of rotation position. Thus, a leakage flow between the fluid inlet 11 and the fluid outlet 12 is inhibited. For this purpose, the rotating section of the pump ring 20 is pressed against the fluid inlet 11 or the fluid outlet 12 by the eccentric, for example, such that it is fluidly sealed from an end face of the pump ring 20.

(6) The pump ring 20 comprises two deformation sections 24, 25 in the circumferential direction U adjacent to each other or across a range of angles in the circumferential direction U. In the first deformation section 24, a deformation force is already applied to the pump ring 20 in the radial direction by the pin 13 extending parallel to the axis of rotation. Additionally, a cavity located at the pin 13 is formed in the pump ring 20 between the pin 13 and the eccentric 30 through which the pump ring 20 can be more easily deformed in the radial direction. The pump ring 20 may, in the first deformation section 24, also comprise further measures for easier deformability as compared to the adjoining second deformation section 25. Due to the easier deformability in the first deformation section 24, a lower torque needs to be applied to the rotor shaft 40 during a rotation across the range of angles of rotation across which the first deformation section 24 extends. In the pump shown as an example, the pre-determined angle of rotation position is therefore symmetrical to the pin 13 on the straight line bisecting the rotor shaft 40 and the pin 13. This pre-determined angle of rotation position may, for example, be defined as 0°, with the depicted eccentric depicted at an angle of rotation position turned by 90° along the rotation path 33. The angle of rotation of the rotor shaft 40 may in the depicted pump, for example, be detected at the rotor shaft 40, at the eccentric 30, at the pump ring 20 by means of the rotating section 21 of the pump ring 20, or at a rotor of a motor not depicted and driving the rotor shaft 40. The eccentric 30 is presently integrally connected to the rotor shaft 40, wherein the rotor shaft 40 may also integrally form the eccentric 30.