WO2008148472A1

WO2008148472A1 - Vane pump

Info

Publication number: WO2008148472A1
Application number: PCT/EP2008/004150
Authority: WO
Inventors: René Constantin SCHEERER; Stefan Merz; Martin Josef Zug; Steffen Reiblein; Gordon Ulrich Mohn
Original assignee: Robert Bosch Gmbh
Priority date: 2007-06-05
Filing date: 2008-05-23
Publication date: 2008-12-11
Also published as: DE102007039172A1; DE102007039172B4

Abstract

The invention relates to a vane pump having a rotor (15'), in which a plurality of vanes (18) is disposed in a radially displaceable manner. The vane pump has at least one first control opening (22) for the suctioning of pressure media into a chamber that is formed between two adjacent vanes (18). The rotor (15') tapers starting in an area having the largest diameter (31) to a first side surface (29) oriented toward the first control opening (22) for the suctioning of pressure media. A smaller radius (32) of the side of the rotor (15') facing the first control opening (22) for the suctioning of pressure media, and a minimum distance of a wall (35) of the first control opening (22) from a rotational axis of the rotor (15') are equal.

Description

Wing cell pump

The invention relates to a vane pump with a rotor in which a plurality of vanes is slidably disposed.

From DE 41 09 149 C3 a vane pump is known, the rotor is rotatably connected to a shaft which is mounted in a housing part. In the housing part connections are provided. The rotor is surrounded in the radial direction by a lifting ring. Between the cam and the rotor are separated by adjacent wings from each other formed a plurality of chambers. The chambers are alternately connected to one of the terminals when the rotor is rotated by the shaft. In a control plate control openings are arranged. The control plate limits the flow cross section, can flow through the pressure medium into the chamber. To connect the control openings with the connection channels formed in the housing part, a disc is provided, which is arranged between the housing part and the rotor.

The rotor has a substantially cylindrical shape, wherein the cylinder jacket surface has a chamfer both to the top surface and to the bottom surface of the rotor. In the described vane pump, it is disadvantageous that a part of the theoretically possible

Inlet cross section of the control opening in the control plate is covered by a side surface of the rotor. As a result, pressure medium flows against the end face of the rotor, whereby a back pressure in the region of the narrowest cross section the tax opening is increased. As a result, the filling behavior deteriorates and the efficiency of the vane pump drops, especially at high speeds.

From DE 24 43 720 and EP 0 068 035 Bl a vane pump is known in each case, are arranged in the two Ansaugsteuernieren on opposite sides of the rotor. As a result, the flow cross-section for filling in the suction of pressure medium in an enlarged chamber increases. The rotors of the vane pump are each made approximately cylindrical.

It is the object of the invention to provide a vane pump in which the filling process is improved, especially at high speeds and thus has an increased efficiency.

The object is achieved by the vane pump with the features of claim 1.

The vane pump according to the invention has a rotor in which a plurality of vanes is arranged displaceably. At least one first control opening is provided, via which pressure medium is sucked in during a rotation of the rotor. The pressure medium is sucked into a chamber formed between two adjacent vanes. The rotor tapers starting from its largest diameter in the direction of one of the at least one first control opening for sucking pressure medium facing side surface. According to the invention, the radius of the side of the rotor facing the first control opening for the suction of pressure medium and a distance of the first of the control opening to the axis of rotation limiting wall of the axis of rotation of the rotor at the mouth of the control opening the same.

By such an arrangement of the control opening and the radial taper of the rotor at least on the

Control opening for sucking pressure medium-facing side can maximize the control opening cross-section without affecting the control time. The dimension of the control opening in the radial direction can be increased by the extension of the chamber to the control surface facing the side surface of the rotor. At the same time by adjusting the diameter of the rotor at least on the at least one control port facing side and the position of the control port for the suction of pressure medium a possible stepless transition when entering pressure medium from the control port into the chamber realized. Through this step-free design of the transition reduces the flow resistance and the filling process is improved. This overall improves the efficiency of the vane pump, it being possible in particular for the speed of the vane pump to be increased owing to the lower flow velocity at a larger flow cross section.

In the dependent claims advantageous developments of the vane pump according to the invention are carried out.

In particular, it is advantageous if the sum of a muzzle angle and an angle between an outer surface of the rotor and the plane of rotation at the transition of the outer surface of the rotor to the side facing the control opening side surface results in 180 °. The outlet angle is the angle between a wall of the first control opening in the direction of the axis of rotation and a plane of rotation of the rotor. This means that at least on the side oriented toward the axis of rotation, when pressure medium enters the chamber, there is a straight-line transition from the control opening into the chamber. Through such a straight transition, in turn, the

Flow conditions when flowing the pressure medium from the control port into the chamber improved.

It is further preferred that a surface portion of the outer surface of the rotor, which extends from the largest diameter of the rotor toward the control surface facing the side surface of the rotor extends curved. The curvature is in particular oriented so that the center of the curvature lies radially outside the rotor. Furthermore, it is preferable for the curved surface to consist of at least two regions, wherein the region further respectively arranged in the direction of the control opening has a larger radius of curvature than the region arranged adjacent thereto in the direction of the largest diameter of the rotor. This leads to a profile which, in turn, has advantageous properties with regard to the flow during the filling of the chamber. In particular, it is advantageous that the pressure medium, which in the region of the largest diameter of the

Rotor is moved with a rotation of the rotor at a greater speed in the circumferential direction than in the region of the smaller diameter on the side surface of the rotor. This results in a larger static pressure in the small diameter portion of the rotor, creating a pressure gradient in the direction of the largest diameter of the rotor. This pressure gradient also provides for an improvement in the filling or to accelerate the filling process. Thus, higher speeds of the vane pump can be realized. Furthermore, it is preferred if the rotor tapers radially starting from its largest diameter toward both side surfaces. By such a bilateral radial taper starting from the region of the largest

Diameter is achieved that a bending load due to asymmetry is avoided. By far in the region of the largest diameter in the radial direction guided wings, the bending moments on the wing can still hold comparatively low.

For further improved filling of the chambers of the vane pump, it is preferred if at least one further control opening for sucking pressure medium is present. This further control opening is arranged on the side facing away from the control port for the suction of pressure medium side of the rotor and connected to the control port for the suction of pressure medium. This can be achieved via an overall flow cross-section, which is composed of two control openings, a filling of the chambers. This is particularly advantageous together with the bilateral radial taper. The different diameters also lead to the emergence of a filling-promoting pressure gradient in the chamber.

The statements made above with regard to the design of the geometry of the control opening and of the rotor on the side facing the control opening apply in the same way to the control opening for the suction of pressure medium as well as to the further control opening or the further control opening facing side of the rotor. Furthermore, it is preferred that the region of the largest diameter of the rotor is arranged off-center. The off-center arrangement is in particular at the two Befüllanteile adapted when two control openings are provided. Even with only one control opening, an asymmetrical arrangement of the area with the largest diameter can be used advantageously. The ratio of a first distance of the region of the largest diameter of the rotor from the first control opening facing side surface of the rotor and a second distance of the region of the largest diameter of the second side surface, which faces the further first control opening, is preferably the ratio of Befüllanteile dependent on the first control opening and the further first control opening. In particular, the ratio of the first distance to the second distance is equal to the ratio of the first Befüllanteils to the second Befüllanteil.

In the drawing, preferred embodiments of the vane pump according to the invention and those components are shown. The preferred embodiments will be explained in more detail in the following description. Show it:

1 shows an example of a vane pump as

Charge pump in a pump unit;

FIG. 2 shows a plan view of a housing part of the vane cell pump according to the invention; FIG.

3 shows a side view of a unilaterally tapered rotor of the vane pump according to the invention;

Fig. 4 shows a cross section through a one-sided tapered

Rotor of the vane pump according to the invention shown in FIG. 3; 5 shows a schematic representation for explaining the advantages of the vane cell pump according to the invention;

6 shows an illustration of a cover of the vane pump with a further control opening for filling the chambers on both sides; and

Fig. 7 is an illustration of a rotor of the vane pump according to the invention with double-sided taper.

In Fig. 1, a pump unit 1 is shown, which is arranged in a housing consisting of a cup-shaped first housing part 2 and a second housing part. The second housing part is designed as a connection plate 3 and closes the cup-shaped housing part. 2

In the cup-shaped housing part 2, a main pump 4 is arranged. The main pump 4 is an axial piston machine in the illustrated embodiment. In the connection plate 3 is an auxiliary pump in the form of a

Vane pump 5 is formed. The main pump 4 and the vane pump 5 are driven by a common drive shaft 6. The drive shaft 6 penetrates the bottom of the cup-shaped housing part 2. At the outstanding there end of the drive shaft 6, a toothing 7 is formed. The toothing 7 makes it possible to connect the drive shaft 6 with a torque-generating device.

The main pump 4 has a cylinder drum 8 in which cylinder bores are arranged in the longitudinal direction. The plurality of cylinder bores is arranged distributed over a circumferential circle in the cylinder drum. In each of these cylinder bores, a piston is arranged longitudinally displaceable. The pistons 7 protrude at one end out of the cylinder drum 8 and are articulated there, each with a shoe 10 connected. The shoe 10 is supported on a swash plate 11. Depending on the inclination angle between the swash plate 11 and the drive shaft 6 lead in a rotation of the

Drive shaft 6, the piston 9 in the cylinder bores and the cylinder drum 8 a lifting movement.

In the connection plate 3, an inlet channel 12 and an outlet channel 13 are formed. Via the inlet channel 12 4 pressure medium is sucked by the main pump. During one revolution of the cylinder drum 8, the cylinder bores on the side facing the connection plate 3 are in contact with the inlet channel 12. As a result, pressure medium is sucked into the cylinder bore and displaced into the outlet channel 13 during a pressure stroke by the piston 9 arranged in the cylinder bores.

The illustrated pump unit 1 is a unit of a charge pump formed by the vane pump 5 and the main pump 4. The vane pump 5 is disposed in a recess 14 in the terminal plate 3 and is also driven by the drive shaft 6. For this purpose, the drive shaft 6 protrudes into the recess 14 with a free shaft end 16. There, the rotor 15 is disposed on the free shaft end 16 and rotatably connected to the free end of the shaft 16. The recess 14 is introduced from the side facing away from the main pump 4 side in the connection plate 3. The recess 14 receives a rotor 15 of the vane pump 5 and a cam ring 19. The cam ring 19 surrounds the rotor 15 and is arranged eccentrically to this. To determine the position of the rotor 15 and thus the eccentricity is shown in the Embodiment, a pressure chamber between the recess 14 and the cam ring 19 is formed. This pressure chamber is connected to the inlet channel 12 via a control pressure line 20. In the pressure chamber thus acts a hydraulic force that tries to adjust the cam ring 19 in Fig. 1 down as a restoring force. In the opposite direction acts in Fig. 1 not recognizable return device on the cam ring 19th

In the rotor 15 a plurality of grooves 17 formed in the radial direction are arranged as vane slots. In each of these grooves 17, a wing 18 is guided. The wing 18 is slidably disposed in the radial direction in the groove 17 and sealingly cooperates with a raceway of the cam ring 19.

The recess 14 of the connection plate 3 is closed by a lid 21 which is simply formed in FIG. For sealing, an O-ring is arranged in a groove of the lid 21.

2 shows an end view of the connection plate 3. In the connection plate 3, the recess 14 is arranged, which is longer in one direction than the diameter of the cam ring 19. This allows the cam ring 19 in the recess 14 move and so its eccentricity with regard to the rotor 15.

For sucking pressure medium through the formed between an outer surface of the rotor 15, the raceway of the cam ring 19 and two adjacent wings 18 chamber a first control kidney 22 is formed in a base of the recess 14 as a first control port for sucking pressure medium. The control kidney 22 extends along a circular arc section. The first control kidney 22 is connected to an intake passage 23. The intake passage 23 is formed in a connection bend 24 of the connection plate 3. In the arrangement of the pump unit 1 in an open circuit is the

Intake passage 23 connected to a tank volume, not shown. Instead of a circular arc and two circular arc sections may be provided, the centers are offset along the adjustment direction to each other. The control kidney then has a straight connecting section which is rounded at the transition to the circular sections.

The pressure medium conveyed by the vane pump 5 is displaced from the chambers into a second control opening formed as a second control kidney 25. The second control kidney 25 is also formed at the bottom of the recess 14 and connected to an exhaust passage 26. The first control kidney 22 and the second control kidney 25 are arranged symmetrically with each other at the bottom of the recess 14. It may also be intended a slight twist of the control kidneys 22 and 25. Furthermore, control notches may be formed in a known manner on the control kidneys 22, 25.

The center line between the first control kidney 22 and the second control kidney 25 simultaneously indicates the direction in which, in an adjustment of the delivery volume of the vane pump 5 of the cam ring 19 is moved. As a result, along this center line also extends a return device, which is not shown in FIG. 2 and is inserted into a bore 27. The restoring device can in the simplest case consist of a voltage applied to the cam ring 19 coil spring, which is supported at the opposite end to a screwed into the bore 20 plug.

3 shows a view of a first side surface of a rotor 15 "of the vane pump 5 according to the invention. The rotor 15 'defines with its outer surface 37 the chambers formed between its outer surface 37 and the inner surface of the cam ring 19. The vanes 18 are shown in FIGS Grooves 17, which in the illustrated embodiment extend in the radial direction for a rotor 15 'The grooves 17 extend from the outer surface 37 to a common circumferential circle, at which the grooves 17 end towards the center of the rotor 15' Ends of the grooves 17, the cross-section of the grooves 17 is slightly increased

Enlargement of the groove cross-section is performed with a relatively large radius to reduce bending stresses in this area. This reduces the notch effect. In the rotor 15 'is centrally formed a through hole 28, wherein the through hole 28 as

Support bearing of the rotor 15 'is formed. The catch storage acts as

Torque transmission device with the free end 16 of the drive shaft 6 together.

FIG. 4 shows a cross section through the rotor 15 '. The rotor 15 'has a first side surface 29 and a second side surface 30. The surface normals of the side surfaces 29 and 30 are parallel to the center line 34 of FIG

Through-hole 28. In the region of the second side surface 30, which is oriented toward the cover 21 of the vane pump 5, the region of the largest diameter 31 of the rotor 15 'is arranged. From there, the rotor 15 'tapers in the direction of its first side surface 29 toward a smaller diameter 32nd

The outer surface 37 of the rotor 15 'is formed by the region with the largest diameter 31 and a subsequent surface portion 33. The surface portion 33 extends curved up to the smaller diameter 32 at the transition of the surface portion 33 to the first side surface 29. The surface portion 33 is concavely curved, wherein the

The radius of curvature in the region adjacent to the region of greatest diameter 31 of the rotor 15 'is smaller than the radius of curvature of the end formed in the region of the smaller diameter 32 of the surface portion 33. The transition from the smaller

The radius of curvature to the larger radius of curvature on the side of the surface portion 33 oriented toward the first side surface 29 may either be continuous or may be generated by a plurality of successively formed regions. The regions each have a radius of curvature, wherein the radius of curvature of the regions in the direction of the first side surface 29 becomes larger and larger.

A cross section through part of the invention

Vane pump 5 is shown in FIG. 5. It can be seen in particular that the smaller diameter 32 at the transition from the surface portion 33 in the first side surface 29 is the same size as the minimum distance of the first control port 22 toward the

Rotation axis 34 towards limiting wall 35 of the rotation axis. In the illustrated embodiment, an orifice angle between the first control kidney 22 to the rotation axis limiting wall 35 and the plane of rotation of the rotor 15 'is a right angle. At the Transition between the first side surface 29 and the surface portion 33 is formed between the surface portion 33 and the plane of rotation of the rotor 19 'also a right angle. The two right angles thus complement each other to 180 °. A diversion of the

Pressure medium when entering the chamber is therefore not required. Because of the identical distance of the wall 35 from the rotation axis 34 and the surface portion 33 in the region of the confluence of the control kidney 22 form no vortex.

As already explained, in the region of the largest diameter 31 of the rotor 15 ', the peripheral speed of the pressure medium in the chamber is greater than in the region of the minimum distance of the wall 35 from the axis of rotation 34. A difference therefore forms between the static pressure in the region of the surface portion 33 at the transition to the first side surface 29 and in the region of the largest diameter 31 of the rotor 15. This pressure difference leads to an improvement in the filling of the chamber. A particularly good utilization of this pressure difference results from the curved design of the surface portion 33. The center of the curvature is in the section through the rotor 15 'in the radial direction outside of the rotor 15'. The radius of curvature becomes larger starting from the region of the largest diameter 31 in the direction of the first side surface 29, wherein either a continuous increase in the radius of curvature or a section-wise enlargement of the radius of curvature can be used. This results in a plurality of successive in the axial direction of portions of the surface portion 33, wherein each further to the first side surface 29 formed toward area has a larger radius of curvature than that in the direction the area of greatest diameter 31 adjacent area.

The illustrated embodiment of Fig. 5 shows one only in one direction to the first

Side surface 29 toward radially tapered rotor 15 '. In this case, the tapering direction is predetermined by the arrangement of the first control kidneys 22.

Due to the radial taper of the rotor 15 'in the direction of the first side surface 29, the radial extent of the first control kidney 22 can be increased considerably. At the same time a good guidance of the wings 18 in the grooves 17 of the rotor 15 'is achieved. The oriented to the free end 16 of the drive shaft 6 toward the end of the blade 18 is shown in phantom in Figure 5 for clarity. It can be seen that the guide length of the blade on the side oriented towards the second side surface 30 of the rotor 15 'is comparatively long. By the curved

Surface portion 33 is still a considerable radial extent of the control kidneys 22, 25 allows. By the guide in the region of the largest diameter 31, however, the maximum bending moment of the wing 18 is reduced. As a result, the deformation of the vane in response to the discharge pressure of the vane pump 5 is lower, so that the leakage losses are reduced.

In the embodiments of FIGS. 4 and 5, only a one-sided taper of the rotor 15 'is shown. However, in an alternative embodiment, the region of the largest diameter 31 may also be displaced, for example, in the direction of the center plane of the rotor 15 '. In particular, it decreases then, the free length of the wing 18 of the guided area in the region of the largest diameter 31. Such a two-sided taper of the rotor 15 'in the direction of the first side surface 29 back and on the second side surface 30 out, can therefore also in one-sided

Filling over only a control kidney 22 be advantageous.

6, a cover 121 of a vane pump 5 is shown with filling on both sides. With the cover 121 instead of the cover 21 of FIG. 1, it is possible to supply pressure medium also from the second side of the rotor 15 '. FIG. 6 shows a plan view of the cover 121 from the side of the connection plate 3. For clarity, the cover 121 together with the rotor 115 is shown. Good to see are formed in the rotor 115 grooves 117. For the sake of clarity, only a groove 117 is provided with a reference numeral. In the grooves 117, a respective wing 18 is arranged. Between the adjacent vanes 18, a chamber 135 is formed, which is bounded outwardly by a raceway 134 of the cam ring 119 and in the direction of the axis of rotation of the vane pump 5 through an outer surface 129 of the rotor 115. In order to be able to fill these chambers 135 with pressure medium not only from the side of the connection plate 3, control openings are also provided in the cover 121. Thus, a further control kidney 122 is provided, which is opposite to the first control kidney 22. Thus, pressure medium is sucked in both via the first control kidney 22 and also via the further first control kidney 22. In a corresponding manner, opposite the second control kidney 25, a further second control kidney 125 is formed in the cover 121. The further first control kidney 122 is connected via an overflow 133 with the intake passage 23 in Connection. For overflow of pressure medium from the intake passage 23, for example, a recess in the cam ring 119, a chamfering of the cam ring 119 or corresponding holes or a groove in the terminal plate 3 may be arranged.

To ensure that the wings 18 are in contact with the inner surface 134 of the cam ring 119 at all times, a guide ring 135 is provided. The guide ring 135 is disposed in a recessed area of the rotor 115. Such a guide ring can also be arranged on both sides of the rotor 115. The wings 18 abut with their oriented in the direction of the axis of rotation towards the end face on the outer circumference of the guide ring 135. This ensures even at low speeds or highly viscous pressure medium that the wings 18 sealingly cooperate with the cam ring 19. The extension / retraction of the wings is ensured by the ring in all operating conditions.

FIG. 7 shows a further preferred exemplary embodiment of a rotor 115 in an end view. The rotor 115 has its raised portion 131 in the center. This is particularly preferred when the Befüllanteile on the first control kidney 22 and the other first control kidney 122 are the same for sucking pressure medium. In this case, a first distance di from the first side surface 129 to the beginning of the largest diameter portion 131 and the second distance d ₂ from the second side surface 130 to the largest diameter portion 131 are equal. As already explained, the bilateral radial taper can be achieved with the resulting central location of the raised area 131 contribute to the prevention of bending stress due to asymmetry even when filling on one side.

In the transition from the concave surface portions 133 and 133 'on the side of the rotor 115 facing the first side surface 129 and the second side surface 130, a transition region 136 or 136' is formed in each case. This transition region 136 or 136 'can be formed, for example, with a curvature of the surface sections 133 or 133' running in the opposite direction to the curvature. Because of the symmetry of the rotor 115 shown in FIG. 7, the corresponding features are provided with the corresponding, primed reference numerals. An alternative embodiment of the rotor 115 without transition region is also conceivable.

At different Befüllanteilen by the first control kidney 22 and the other first control kidney 122, the region of the largest diameter 131 may be arranged in an embodiment of the rotor 115, not shown, outside the center plane of the rotor 115. In particular, the ratio di to U ₂ is then preferably equal to the ratio of the filling proportions via the first control opening 22 and the further first control opening 122.

In order to keep the bending moments on the wings 18 as small as possible, it is preferred if the area of the largest diameter 131 is formed so that the median plane between the first side face 129 and the second side face 130 lies within the area 131. The asymmetrical displacement corresponding to the Befüllanteilen can then be done by displacement in the direction of the first side surface 129 or the second side surface 130 through the transition regions 136 or 136 '. The invention is not limited to the illustrated embodiment. In particular, advantageous combinations of individual features of the individual embodiments are possible with each other.

Claims

claims

A vane pump having a rotatable rotor (15 ¹ , 115) in which a plurality of vanes (18) is slidably disposed and having at least a first control port (22) for drawing pressure medium into a chamber formed between two adjacent vanes (18) , wherein the rotor (15 ', 115), starting from a region largest

Diameter (31, 131) in the direction of a to the first control port (22) for the suction of pressure medium oriented side surface (29, 129, 130) radially tapered, characterized in that a smaller radius (32, 132, 132 ') of Rotor (15 ', 115) on the first control opening (22) for the suction of pressure medium oriented side of the rotor (15 ¹ , 115) and a distance of a first control opening (22) to a rotation axis limiting wall (35) equal are.

2. vane pump according to claim 1, characterized in that the sum of a mouth angle between the

Wall (35) of the first control opening (22) and a plane of rotation of the rotor (15 ', 115) and an angle between an outer surface (29, 129) of the rotor (15 ¹ , 115) in the transition to the first side surface (29, 129 ) and the plane of rotation is 180 °.

3. vane pump according to claim 1 or 2, characterized in that between the region largest diameter (31, 131) and one of the first control opening (22) facing side surface (29, 129) of the rotor (15 ¹ , 115) formed surface portion ( 33, 133) in axial direction curved.

4. vane pump according to claim 3, characterized in that the curved surface portion (33, 133) is composed of at least two regions, wherein each further in the direction of the control opening (22) arranged region has a larger radius of curvature in the axial direction.

5. vane pump according to one of claims 1 to 4, characterized in that the rotor (15 ', 115) to both side surfaces (29, 30; 129, 130) out starting from its largest diameter area (31, 131) radially tapers ,

6. Vane pump according to one of claims 1 to 5, characterized in that the vane pump (5) has at least one further first control opening (122) on the side facing away from the first control port (22) for sucking pressure medium side of the rotor (15 ', 115) is arranged and connected to the first control opening (22).

7. vane pump according to claim 6, characterized in that the sum of a mouth angle of the further first control opening and an angle between an outer surface (129 ') of the rotor (115) in the transition to a further first control opening (122) facing side surface (130) and the plane of rotation is 180 °.

8. vane pump according to claim 6 or 7, characterized in that between the region of the largest diameter (131) and one of the further first control surface (122) facing side surfaces of the rotor (130, 115) formed further surface portion (133 ¹ ) extends curved in the axial direction.

9. vane pump according to claim 8, characterized in that the curved further surface portion (133 ¹ ) is composed of at least two areas, wherein each further in the direction of the other first control opening (122) arranged region has a larger radius of curvature in the axial direction.

10. Vane pump according to one of claims 6 to 9, characterized in that the region of greatest diameter (31, 131) has a first distance (di) from the first side surface (29, 129) and a second distance (d ₂ ) from the second Side surface (130), wherein the ratio of the first and the second distance (di, d ₂ ) depends on a ratio of the Befüllanteile on the control port (22) and the further control port (122).