Rotary vane pump

Abstract

The present disclosure relates to a rotary vane pump (1) comprising a pump housing (2), a stator (14), a rotor (5), a plurality of vanes (12) housed in the rotor (5) so as to be displaceable in a radial direction, thereby delimiting a plurality of pump chambers (30) between the vanes themselves and the stator (14) and the rotor (5), wherein a radially inner cam surface (16) is provided on which the vanes (12) rest, wherein secondary chambers (32) are delimited between the cam surface (16) and the rotor (5) in the radial direction and between the vanes (12) in a circumferential direction, wherein the secondary chambers are assigned a suction inlet (36) and a pressure outlet (38).

Description

Technical Field

[0001] This invention relates to a rotary vane pump, and more particularly to a rotary vane pump for hydraulic fluids. Background Technology

[0002] Rotary vane pumps, also known as centrifugal pumps, are commonly known. A rotary vane pump has a stator, a rotor arranged inside the stator, and multiple vanes that are displaceably housed in the rotor. A pump chamber is defined between every two adjacent vanes in the circumferential direction.

[0003] One embodiment of a rotary vane pump comprises a hydraulic unit in which the rotor is driven by an electric motor. The rotary vane pump provides a volumetric flow rate of hydraulic fluid, which can be used, for example, to supply a clutch actuator or a gear actuator. Summary of the Invention

[0004] The object of the present invention is to create a rotary vane pump characterized by having a particularly high delivery rate.

[0005] To address this problem, the present invention provides a rotary vane pump comprising a pump housing, a stator, a rotor, and a plurality of vanes housed within the rotor for radial displacement, thereby defining a plurality of pump chambers between the vanes themselves and the stator and rotor. A cam surface is provided radially inward, upon which the vanes rest. Secondary chambers are defined between the cam surface and the rotor in the radial direction and between the vanes in the circumferential direction, and these secondary chambers are assigned suction inlets and pressure outlets. The cam surface ensures “positive guidance” of the vanes, thereby reliably resting the vanes against the stator and providing a seal thereon, even at particularly low speeds. The rotary vane pump according to the invention can therefore operate at very low speeds where the centrifugal force acting on the vanes is insufficient to reliably rest the vanes against the stator and provide a seal thereon. At such low speeds, the cam surface ensures contact between the vanes and the stator. Furthermore, in the secondary chamber, which is allocated an intake inlet and a pressure outlet, a region of the rotary vane pump is used to generate a volumetric flow rate that is typically negligible in terms of flow rate—that is, the volume between the cam surface and the rotor. Also in this region, if the intake inlet and pressure outlet are provided in appropriate locations, the design allows for a chamber that can be used to deliver hydraulic fluids. This results in very high overall efficiency.

[0006] The cam surface is preferably located axially inside the rotor, thus creating a compact design in the axial direction. Furthermore, additional axial space is available in the region of the cam surface, where bearings can be positioned to support the rotor within the pump housing.

[0007] The width of the cam surface in the axial direction is preferably 5% to 15% of the axial length of the rotor. This value has proven to be a good trade-off between, on the one hand, not too high surface pressure between the blade and the cam surface, and on the other hand, the maximum possible axial length of the rotor.

[0008] The cam surface can be integrated with the end wall of the pump housing, thus eliminating the need for separate assembly.

[0009] The connecting channel of the pump chamber can be formed radially within the cam surface, thus achieving a compact overall design.

[0010] According to one embodiment of the invention, a volume within the rotor, defined by slots for receiving blades, end walls of the pump housing, and end faces of the blades, connects to the suction inlet and pressure outlet. In addition to the main delivery chamber and the secondary chamber, this volume represents a third type of chamber for delivering hydraulic fluid. In these chambers, the blades operate in a pump piston manner, drawing hydraulic fluid into or expelling it from the chamber as the blades are pushed out or pushed into the slots in the radial direction with the rotation of the rotor.

[0011] According to one embodiment of the invention, the blades are designed in a stepped manner on the radially inner side, having a guide surface that mates with the cam surface, and another radially inner end face housed in the rotor. The radial offset between the guide surface and the inner end face of the blade forms a seal in this region of the cam surface, thereby preventing hydraulic short circuits in this region.

[0012] The length of the end face protruding from the guide surface can be approximately 5% to 15% of the blade height. This value is sufficient to ensure the desired seal is achieved in this area. Attached Figure Description

[0013] The invention will now be described with reference to the embodiments shown in the accompanying drawings. In the drawings:

[0014] - Figure 1 A perspective view of a rotary vane pump is shown, in which a portion of the casing is shown as transparent so that the pump's internal workings can be seen.

[0015] - Figure 2 It shows Figure 1 The rotary vane pump in which the casing cover has been removed;

[0016] - Figure 3 The first cross-section of a rotary vane pump is shown;

[0017] - Figure 4 The second cross-section of a rotary vane pump is shown;

[0018] - Figure 5 It shows along Figure 4A three-dimensional view of the cross-section of plane VV in the middle;

[0019] - Figure 6 It shows along Figure 4 A three-dimensional view of the cross-section of the mid-plane VI-VI;

[0020] - Figure 7 A cross-section along plane VI-VI is shown, in which some portions of the pump housing are shown as transparent, thus allowing the fluid passages to be seen;

[0021] - Figure 8 It shows along Figure 4 The cross section of plane VII-VII in the middle; and

[0022] - Figure 9 Shown at an enlarged scale Figure 8 Details IX. Detailed Implementation

[0023] Figures 1 to 9 A rotary vane pump 1 is schematically shown, which can be used in particular to provide a volumetric flow rate of hydraulic fluid in a hydraulic unit.

[0024] The rotary vane pump 1 has a pump housing 2, which is formed by a body 3 and a housing cover 4. A rotor 5 is arranged inside the housing and mounted on a shaft 6 for joint rotation. This can be driven by an electric motor (not shown).

[0025] The rotary vane pump is a two-stroke pump, therefore the housing cover 4 has two inlet openings 7 and two delivery openings 8.

[0026] The rotor 5 has multiple slots 10, each slot receiving a blade 12.

[0027] The radial outer end of the blade interacts with the inner surface of the stator 14 housed in the pump casing 2.

[0028] The rotary vane pump 1 has a cam surface 16, on which the radially inner side of the vane 12 rests.

[0029] The cam surface 16 is formed here as a protrusion on the end face of the body 3 facing the rotor 5, wherein the rotor 5 is designed to be axially shorter in this region. The rotor 5 is designed to have its full width in its radially outer region (see...). Figure 4 This causes the rotor 5 and the cam surface 16 to overlap (in...) Figure 4 (In the right-hand plane region of the midsection).

[0030] Specifically, blade 12 has a guiding surface 18 (see especially) Figure 9 The guiding surface is stepped relative to the radially inward end face 20 of the blade 12 (see especially). Figure 3 ).

[0031] The height of step h (see) Figure 3 It is approximately 5% to 15% of the total height H of the blade 12.

[0032] The width b of the guide surface 18 (see also) Figure 3 It is approximately 10% to 15% of the total width B of the blade 12.

[0033] The cam surface 16, together with the guide surface 18, provides positive guidance for the blade 12, which ensures that the blade 12 will move outward even when the centrifugal force is relatively small as the rotor 5 rotates.

[0034] For example, especially in Figure 8 As can be seen, the path of the cam surface 16 corresponds to the envelope profile formed by the guide surface 18 of the blade 12, which is generated when the rotor 5 rotates and the blade 12 simultaneously contacts the stator 14. It is advantageous, for example, to design the blade 12 to be of uniform thickness in this region; the radii of the outer and inner guide surfaces may actually be different, but they should have a common central axis. It is possible to deviate from this, because a functionally suitable envelope profile can still be constructed nonetheless.

[0035] For example, especially in Figure 8 As can be seen, the path of the cam surface 16 corresponds to the path of the inner contour of the stator 14. In other words, the distance between the cam surface 16 and the inner surface of the stator 14, measured in the radial direction, is constant along the circumference of the cam surface.

[0036] Due to the offset between the guide surface 18 and the other inner end face 20 of the blade, a shoulder 22 is formed, which serves as a seal. The shoulder 22 prevents hydraulic fluid from entering the corresponding slot 10 in the rotor 5 from the delivery chamber between the blades 12.

[0037] The special feature of the rotary vane pump 1 is that it uses a total of three different types of delivery chambers to provide volumetric flow rate.

[0038] The majority of the volumetric flow rate is provided by the main chambers, which are defined circumferentially between adjacent blades 12 and radially between the rotor 5 and the stator 14. In the axial direction, the main chambers, indicated here by reference numeral 30, are defined between the opposite end faces of the body 3 and the housing cover 4 of the pump housing 2.

[0039] Another type of delivery chamber is formed by a secondary chamber 32 defined between the cam surface 16 and the inner surface 34 of the rotor 5 opposite to the cam surface 16. Figure 7 In region I, the radial height of these secondary chambers is almost zero, while their radial height is... Figure 7It is the largest in region II.

[0040] Figure 7 A suction inlet 36 and a pressure outlet 38 associated with the secondary chamber 32 are also shown. Figure 7 The pump shown has two different displacements for each pump flow. The pump flow with the smaller displacement has a simplified inlet port in the form of two orifices leading to the rotor chamber of the motor; this pump flow is used to cool the motor. The pressure port of the secondary chamber 32 of the smaller pump flow leads to the suction area of ​​the main chamber via a groove. If the pump strokes are the same, it is advantageous to design both pump flows with an inlet outlet 36 and a pressure outlet 37.

[0041] Finally, there is a third type of delivery chamber, referred to below as auxiliary chamber 40. These auxiliary chambers are formed in slots 10 of the rotor 5, between the rotor wall and the end face 20 of the blades 12. Here, the blades 12 function similarly to the pistons of a piston pump, because during each rotation they are pushed into the corresponding slots 10 twice (corresponding to the jetting motion of the hydraulic fluid) and pushed axially outward twice (corresponding to the entry phase).

[0042] The associated inlet and pressure ports are indicated here by reference numeral 42.

[0043] Due to these three different types of delivery chambers, the rotary vane pump 1 has a particularly large displacement per rotation, and therefore has a high delivery capacity and a small overall volume.

Claims

1. A rotary vane pump (1), characterized in that, The rotary vane pump includes a pump housing (2), a stator (14), a rotor (5), and a plurality of vanes (12) housed in the rotor (5) for radial displacement, thereby defining a plurality of pump chambers (30) between the vanes themselves and the stator (14) and the rotor (5), wherein a cam surface (16) is radially inwardly located, the vanes (12) resting on the cam surface, wherein a secondary chamber (32) is defined between the cam surface (16) and the rotor (5) in the radial direction and between the vanes (12) in the circumferential direction, wherein the secondary chamber is provided with a suction inlet (36) and a pressure outlet (38), the cam surface (16) being integrally formed with the end wall of the pump housing (2), the vanes (12) being steppedly designed on the radially inward side having a guide surface (18) that mates with the cam surface (16), and another radially inwardly located end face (20) housed in the rotor (5).

2. The rotary vane pump according to claim 1, characterized in that, The cam surface (16) is axially located inside the rotor (5).

3. The rotary vane pump according to claim 1, characterized in that, The width (b) of the cam surface (16) in the axial direction is between 5% and 15% of the axial length (B) of the rotor (5).

4. The rotary vane pump according to any one of the preceding claims, characterized in that, The connecting channel (42) for the pump chamber (40) is formed radially within the cam surface (16).

5. The rotary vane pump according to claim 1, characterized in that, The volume inside the rotor (5) defined by the slot (10) for receiving the blade (12), the end wall of the pump housing (2) and the end face (20) of the blade (12) is connected to the suction port (7) and the pressure outlet (8).

6. The rotary vane pump according to claim 1, characterized in that, The length (h) by which the end face (20) protrudes from the guide surface (18) is 5% to 15% of the height (H) of the blade (12).

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