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EP-4273404-B1 - ROTARY VANE PUMP

EP4273404B1EP 4273404 B1EP4273404 B1EP 4273404B1EP-4273404-B1

Inventors

  • Stössel, Roland

Dates

Publication Date
20260513
Application Date
20230419

Claims (6)

  1. Rotary vane pump (1) having a pump housing (2), a stator (14), a rotor (5), a plurality of vanes (12) which are accommodated in the rotor (5) so as to be displaceable in the radial direction, so that they delimit a plurality of pump chambers (30) between themselves, the stator (14) and the rotor (5), wherein a radially inner cam surface (16) is provided, against which the vanes (12) rest, wherein secondary chambers (32) are delimited in the radial direction between the cam surface (16) and the rotor (5) and in the circumferential direction between the vanes (12), with a suction inlet (36) and a pressure outlet (38) being assigned to the secondary chambers, the cam surface (16) is formed in one piece with an end wall of the pump housing (2), characterized in that the vanes (12) are designed in a stepped manner on the radially inner side, with a guide surface (18) which cooperates with the cam surface (16), and a radially further inner end face (20) which is accommodated within the rotor (5).
  2. Rotary vane pump according to claim 1, characterized in that the cam surface (16) is located axially inside the rotor (5).
  3. Rotary vane pump according to claim 1 or 2, characterized in that the cam surface (16) has a width (b) in the axial direction of between 5% and 15% of the axial length (B) of the rotor (5).
  4. Rotary vane pump according to one of the preceding claims, characterized in that connection channels (42) for pump chambers (40) are formed radially within the cam surface (16).
  5. Rotary vane pump according to one of the preceding claims, characterized in that the volume inside the rotor (5) delimited by the slots (10) for receiving the vanes (12), the end walls of the pump housing (2) and the end faces (20) of the vanes (12) is connected to a suction inlet (7) and a pressure outlet (8).
  6. Rotary vane pump according to one of the preceding claims, characterized in that the end face (20) protrudes beyond the guide surface (18) by a length (h) in the order of 5% to 15% of the height (H) of the vane (12).

Description

The invention relates to a rotary vane pump, in particular for hydraulic fluid. Rotary vane pumps, also known as vane pumps, are generally known. They have a stator, a rotor arranged inside the stator, and a plurality of vanes which are displaceably accommodated in the rotor. A pump chamber is defined between each two adjacent vanes in the circumferential direction. One application of a rotary vane pump is constituted by hydraulic units in which the rotor is driven by an electric motor. The rotary vane pump then provides a volume flow of hydraulic fluid which can be used, for example, to supply a clutch actuator or a gear actuator. US2099193A discloses a rotary vane pump according to the preamble of claim 1. The object of the invention is to create a rotary vane pump that is characterized by a particularly high delivery rate. To solve this problem, a rotary vane pump is provided in accordance with the disclosure as defined by claim 1, having a pump housing, a stator, a rotor, a plurality of vanes which are accommodated in the rotor so as to be displaceable in the radial direction, so that they delimit a plurality of pump chambers between themselves, the stator and the rotor, wherein a radially inner cam surface is provided, against which the vanes rest, wherein secondary chambers are delimited in the radial direction between the cam surface and the rotor and in the circumferential direction between the vanes, with a suction inlet and a pressure outlet being assigned to the secondary chambers. The cam surface ensures a "positive guidance" of the vanes so that they reliably rest against the stator and provide a seal there, even at particularly low speeds. The rotary vane pump according to the invention can therefore be operated at very low speeds, at which the centrifugal forces acting on the vanes are not sufficient for the vanes to reliably rest against the stator and provide a seal there. At such low speeds, the cam surface ensures that the vanes are in contact with the stator. Furthermore, with the secondary chambers, to which a suction inlet and a pressure outlet are assigned, a region of the rotary vane pump is used to generate the volume flow that is usually ignored with regard to the flow rate, namely the volume between the cam surface and the rotor. In this region, too, the design results in chambers that can be used to convey the hydraulic fluid if a suction inlet and a pressure outlet are provided at suitable positions. This results in a very high overall efficiency. The cam surface is preferably located axially inside the rotor, resulting in a compact design in the axial direction. Furthermore, additional axial space is available in the region of the cam surface, in which space a bearing can be arranged for supporting the rotor in the pump housing. The cam surface preferably has a width in the axial direction of between 5% and 15% of the axial length of the rotor. This value has proved to be a good compromise between, on the one hand, a not excessively high surface pressure between the vans and the cam surface and, on the other hand, the greatest possible axial length of the rotor. According to the invention, the cam surface is formed in one piece with an end wall of the pump housing so that no separate assembly is required. Connection channels for pump chambers can be formed radially within the cam surface, resulting in a compact design overall. According to one embodiment of the invention, the volume inside the rotor delimited by the slots for receiving the vanes, the end walls of the pump housing and the end face of the vanes is connected to a suction inlet and a pressure outlet. This volume, in addition to the main delivery chambers and the secondary chambers, represents a third type of chamber used to deliver hydraulic fluid. Within these chambers, the vanes operate in the manner of pump pistons, drawing hydraulic fluid in and displacing it out of the chambers when the vanes are pushed out of or into the slot as the rotor rotates in the radial direction. According to the invention, the vanes are designed in a stepped manner on the radially inner side, with a guide surface which cooperates with the cam surface, and a radially further inner end face which is accommodated within the rotor. The radial offset between the guide surface and the inner end face of the vanes results in a seal in the region of the cam surface, so that a hydraulic short circuit is avoided in this region. The end face can protrude beyond the guide surfaces by a length in the order of 5 to 15% of the height of the vane. This value is sufficient to ensure that the desired seal is achieved in this region. The invention will be described below on the basis of an embodiment which is illustrated in the appended drawings. In the drawings: Figure 1 shows a perspective view of the rotary vane pump, wherein part of the housing is shown transparent so that the inner workings of the pump are visible;Figure 2 shows the rotary vane pum