AU2002321775B2

AU2002321775B2 - Vane pump rotor

Info

Publication number: AU2002321775B2
Application number: AU2002321775A
Authority: AU
Inventors: Alberto Anastasi; Leonardo Cadeddu; Alessandro Fauda; Emilio Samanni
Original assignee: VHIT SpA
Current assignee: VHIT SpA
Priority date: 2001-06-01
Filing date: 2002-05-29
Publication date: 2008-09-04
Anticipated expiration: 2022-05-29
Also published as: JP4276064B2; WO2002097274A2; ITTO20010521A0; RU2294455C2; WO2002097274A3; ITTO20010521A1; CN1325799C; PL206620B1; WO2003030296A2; PL374324A1; AU2002361947A1; ES2394298T3; EP1409874B1; WO2002097274A8; RU2003136732A; CN1533479A; EP1409874A2; JP2004526905A; MXPA03011069A; WO2003030296A3

Description

1 Rotor with reduced wear and pump comprising such a A rotor The present invention relates mainly to a rotor with 0 c 5 reduced wear and to a pump comprising such a rotor, such a pump being used particularly in the motor vehicle industry as an air vacuum source for brake boosting devices. The present invention also relates to CI combined pumps used, for example, both as a vacuum c- 10 source and in order to feed fuel to a thermal engine.

c- Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

Pumps of a known type, in particular used as an air vacuum source, are vane pumps comprising at least one vane and a rotor connected to a drive device, for example a shaft driven in rotation, for example a camshaft. The rotor comprises a vane carrier, at least one vane and an element for the transmission of a drive torque to the camshaft. The vane carrier comprises a cavity located at a first axial end oriented toward the drive shaft and at a second end opposite the first end, at least one slot extending axially and partially from the second end toward the first end, the vane being mounted movably in translational motion in said slot.

At least one pump of the type described above is arranged at one end of the camshaft, and the rotor is driven in rotation by means of the transmission element driven by the shaft, thus ensuring the extraction of the air and the generation of a vacuum.

In a known way, the rotor is produced from steel.

However, in order to reduce its weight and its cost, the vane carrier is produced from plastic, although the transmission element is still produced from steel since 2 00 it directly receives the torque from the drive device.

Problems of reliability may then arise, to be precise the contact between the transmission element and the Cvane carrier may cause the wear of the vane carrier.

In actual fact, in a known way, the axis of the vacuum

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pump and the axis of the drive means, for example an electric motor, are not perfectly coaxial, and, consequently, the transmission element arranged at the end of the drive shaft and transmitting the rotational Mmovement to the vane carrier likewise has a radial displacement with respect to the body of the vane carrier, this displacement being liable to cause wear as a result of the friction of the vane carrier.

There is no possibility of envisaging the use of special materials resistant to frictional wear in order to produce the vane carrier and affording the same advantages as plastic, since the latter have a high cost price.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

According to a first aspect of the invention there is provided a rotor, comprising a transmission element, a vane carrier and at least one vane, said transmission element transmitting a torque to said vane carrier, wherein the vane carrier comprises interposed elements immovable radially with respect to the vane carrier and arranged in the region of bearing surfaces between the transmission element and the vane carrier in order to transmit the bearing force of the transmission element of the vane carrier, wherein said interposed elements are resistant to wear caused by the friction of the transmission element, the interposed elements comprise two parallel wings, the two wings are connected by means of a plate, the interposed elements are secured 3- 00 to a central rod carried by the vane carrier, and C wherein the plate comprises an orifice, into which issue at least two tabs cooperating with the central Crod carried by the vane carrier.

IN Unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the Ssense of "including, but not limited to".

A preferred subject of the present invention is also a rotor, wherein the wings extend perpendicularly to the plate and on the same side of the plate.

A preferred subject of the present invention is also a rotor, wherein the wings are symmetrical with respect to a longitudinal axis of the plate.

A preferred subject of the present invention is also a rotor, wherein the plate comprises fastening means cooperating with second fastening means carried by the vane carrier.

A preferred subject of the present invention is also a rotor, wherein the fastening means carried by the plate comprise an orifice of smaller diameter edged with a sleeve, and in that the fastening means comprise a rod 4 OO of larger diameter carried by the vane carrier, said rod being equipped with an annular bead which projects on the periphery and is formed after the force mounting )of the plate around the rod, and in that the sleeve is arranged between the bead and the transmission element after mounting.

A preferred subject of the present invention is also a rotor, wherein the plate comes to bear on a bearing surface formed in the periphery of said rod Mperpendicularly to the axis of the rod.

(1 A preferred subject of the present invention is also a rotor, wherein the transmission element is made from metallic material and the vane carrier is made from plastic.

A preferred subject of the present invention is also a rotor, wherein the transmission element is produced from steel.

A preferred subject of the present invention is also a rotor, wherein the interposed element is produced from metallic material.

A preferred subject of the present invention is also a rotor, wherein the interposed element is produced from spring steel.

A preferred subject of the present invention is also a rotor, wherein the interposed element is produced by bending.

A preferred subject of the present invention is also a rotor, wherein the fastening means carried by the plate of the interposed element are produced by stamping.

A preferred subject of the present invention is also a rotor, wherein the interposed elements are incorporated 5 00 into the plastic vane carrier during the manufacture of the vane carrier by molding, the interposed elements being formed by wings arranged in the region of the 1bearing surfaces between the transmission element and the body of the vane carrier.

According to a second aspect of the invention there is provided a pump forming at least one vacuum source, wherein it comprises at least one rotor according to 1 10 the present invention.

A preferred subject of the present invention is also a pump, wherein the element is driven by a camshaft.

A preferred subject of the present invention is also a pump, wherein the element is driven by an electric motor.

A preferred subject of the present invention is also a pump, wherein the element is driven by a pulley driven by a belt.

According to a third aspect of the invention there is provided a method for manufacturing of a rotor according to the present invention, comprising the step of manufacturing the vane carrier by plastic molding, wherein it comprises, furthermore, the step of arranging the wings, before the injection of the plastic into the mold for manufacturing the vane carrier, in such a way that said wings are arranged in the region of the bearing surfaces between an element for the transmission of a rotation torque and the vane carrier, and in such a way that they are made immovable from the body of the vane carrier during the removal of the vane carrier from the mold.

It has always been thought that, to avoid damage to the rotor caused by the friction of the transmission 6 00 element, the rotor had to be produced from materials with much greater resistance to wear or the connection between the transmission element and the rotor had to 1be modified accordingly, which, in both cases, presents problems of high cost. The Applicant, then, realized that, without the pump of the known type having to be modified, the addition of a part of simple manufacture in the pump in the region of the transmission element/vane carrier connection, said part being fixed e 10 with respect to the vane carrier, appreciably reduced My the wear of the rotor.

c-I These advantages are exhibited by the invention, particularly and preferably, by means of a pump comprising a rotor comprising an element for the transmission of a torque received by a drive shaft, a vane carrier driven by the transmission element, and at least one vane, said vane carrier likewise comprising an element interposed between the transmission element and the body of the vane carrier, the interposed element being radially immovable with respect to the vane carrier.

In other words, the first element preferably drives a second element in rotation, the second element comprising an insert means immovable radially with respect to the second element in contact with the first transmission element and resistant to the frictional wear caused by the radial displacement of the first element.

The present invention will be understood more clearly from the following description and from the accompanying Figures in which: Figure 1 is a three-quarter view of a pump according to the present invention,

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7 Figure 2 is a three-quarter view of a first embodiment of a bearing element according to the present invention, Figure 3 is an isometric perspective view of a rotor comprising the element of Figure 2, Figure 4 is a top view of Figure 3 without the bearing element, Figure 5 is a three-quarter view of a second embodiment of a rotor according to the present invention, Figure 6 is a sectional view of a bearing element/transmission element assembly according to the present invention, Figure 7 is a view of a detail of Figure 6, Figure 8 is a three-quarter view of a third embodiment of a rotor according to the present invention.

An interposed element 1 comprising at least two wings 3, 5, advantageously in one piece and connected by means of a plate 7, can be seen in Figures 1 and 2. The plate 7 is substantially plane in terms of a first longitudinal dimension 1 and a second transverse dimension L, which are much greater than a third dimension e, and has a longitudinal axis XX', the plate 7 comprising two longitudinally opposed branches 9, 11.

The wings 3, 5 extend from the branches 9, 11 in the direction of the arrow F perpendicularly to the plane of the plate, said wings being opposite to one another with respect to the axis XX' The plate 7 likewise comprises means 13 for fastening the part 1 to a rotor. The fastening means comprise at least two tabs 15, 17 issuing into an orifice 21 formed at the center of the plate 7. The tabs 15, 17 are 8 delimited by four slots 23 formed in the plate 7 and extending radially from the orifice 21 in the direction of the outer periphery of the plate 3 and advantageously parallel to one another. Advantageously, the slots form a non-zero angle with the longitudinal axis XX' of the plate 3.

The part 1 is fastened, blocked, to the rotor by being force-fitted onto a rotor part cooperating with the orifice 21 by means of the tabs 15, 17 which are elastic in a transverse direction to the plane of the plate 7.

The part 1 is advantageously produced from a metallic material, for example from spring steel.

The part 1 is advantageously produced by bending.

A vane pump 33 according to the present invention can be seen in Figure 1, said pump comprising a rotor (Figures 3 and 4) mounted in a pump body and driven, for example, by a camshaft of a motor vehicle engine (not illustrated). The rotor comprises a vane carrier 37, an element 39 for the transmission of the torque of the vehicle engine to the vane carrier, a vane (not illustrated) and a bearing part 1. The vane carrier 37 comprises a body 37' advantageously produced from plastic and equipped at a first longitudinal end with a first portion 36 of smaller outside diameter and with an axis YY', formed by a blind sleeve 41, and, at a second end opposite the first end, with a cylindrical second portion 38 of larger outside diameter, coaxial to the first portion 36 and connected to the first portion 36 of smaller outside diameter by means of a shoulder 40. The sleeve 41 has an internal shape with a cruciform cross section, advantageously with four branches. The branches of the cross are separated, advantageously by means of spherical segments 43, and the inner surface of the branches comprise faces 61

I

9 extending radially and parallel to the axis YY'. The cylindrical portion 38 of larger outside diameter is equipped with a slot 42 capable of receiving a vane, the slot 42 extending axially along YY' from a first longitudinal end to a second longitudinal end formed partially by the shoulder 40, and passing radially through the sleeve 41.

The body 37' of the vane carrier 37 likewise comprises a rod extending from the bottom of the sleeve 41 toward the open end of the sleeve and parallel to the axis yy'.

The transmission element 39 comprises a base 50 of axis YY' with four branches 51, 53, 55, 57 arranged in the form of a cross and connected by means of portions of an arc of a circle 47, and an advantageously oblong central orifice 49 allowing the passage of the rod The transmission element 39 likewise comprises, on one face of the base 50, radially opposite dogs 56 which project and which extend axially from the branches 51, 53 along the axis YY' The branches 55, 57 of the transmission element 39 comprise faces 59, 60 respectively extending in a radial direction and in a direction parallel to the axis YY' and opposite to one another with respect to the axis YY'.

The transmission element 39 is arranged in the inner recess of the sleeve 41 of the body 37' of the vane carrier, the portions of an arc of a circle 47 opposite the spherical segments 43, the rod 45 penetrating into the orifice 49, the face comprising the dogs 56 being oriented toward the outside, and the faces 59, 60 each cooperating respectively with a face 61 of the inner surface of the sleeve.

10 The transmission element is advantageously produced from metallic material, for example from steel.

The vane carrier 37 comprises an interposed element 1 according to the present invention, in such a way that the wings 3, 5 of the element 1 are inserted between the transmission element 39 and the body 37' of the vane carrier 37 between the surfaces 59, 60 and the faces 61 and transmit the bearing force of the transmission element 39 to the vane carrier 37. The element 1 is mounted on the vane carrier 37 in such a way that there is no radial movement of the wings with respect to the vane carrier 37, thus preventing wear caused by the friction of the vane carrier. According to the first embodiment, the element 1 is secured to the body 37' of the vane carrier by the snapping of the plate 7 connecting the wings 3, 5 in the direction of the arrow onto the free end of the rod by means of the tabs 15, 17.

The element 1 is resistant to frictional wear during the displacement of the transmission element with respect to the vane carrier, and the body of the vane carrier then does not experience the wear caused before by the friction of the transmission element 39 on the body 37' of the vane carrier 37, without the transmission of the torque being modified.

Consequently, a pump having a prolonged useful life is obtained.

Moreover, the element 1 advantageously makes it possible to secure the transmission element 39 to the vane carrier 37, thus preventing the separation of the transmission element 39 from the vane carrier 37 during manipulations of the pump comprising such a device.

A second embodiment of an element 101 according to the present invention can be seen in Figure 5, this differing from the element 1 according to the first 11 embodiment in the means for securing the element to the vane carrier.

We shall therefore describe in detail only the securing means.

The element 101 comprises first means 113a for securing the element 101 to the body 137' of the vane carrier without radial movement, said first securing means cooperating with second means 113b for securing the element to the body of the vane carrier, said second securing means being carried by the body of the vane carrier. The first means 113b comprise an orifice 121 arranged substantially at the center of the plate 107 and a sleeve 123 edging the orifice 121 and extending perpendicularly to the surface of the plate 107 in the opposite direction to that in which the wings 103, 105 extend.

In Figure 6 and in Figure 7, which illustrates an enlarged detail, designated by A, of Figure 6, can be seen the rotor of axis YY' according to the second embodiment, comprising the second means 113b. The second means 113b are formed by a central rod 145 carried by the body of the vane carrier 137 of an outside diameter D greater than the diameter of the orifice 121 formed in the plate 107 of the element 101.

The rod 145 advantageously comprises a bearing surface 150 for the bearing element 101, the surface 150 being formed by an annular offset formed on the periphery of the rod 145 substantially perpendicularly to the axis YY', in such a way that, when the transmission element 139 and the bearing element are arranged in the vane carrier, a part of the plate 107 which surrounds the orifice 121 rests on the offset 150.

The element 101 is then secured to the vane carrier, after the installation of the transmission element 139, 12 by the sleeve 123 being force-fitted around the rod 145. During assembly, owing to the difference in diameter between that d of the orifice 121 and that D of the rod 145, there is a temporary elastic reduction in the diameter D of the rod 145. Then, when the plate 107 comes to bear against the annular bearing surface 150, the rod 145 expands elastically, at the same forming an annular bead 146, in such a way that the sleeve 123 is arranged between the transmission element 139 and the bead 146 after mounting.

Moreover, the first securing means 113a, more specifically the sleeve 123, is advantageously produced by stamping, thus giving the connection 148 between the plate 7 and the sleeve 123 a substantially rounded shape, which, when the pump is in operation, has the advantage of reducing the risks of wear of the central rod 145 and also of avoiding the formation of chips during the mounting of the element 101 on the vane carrier.

Furthermore, the means 101 advantageously makes it possible to secure the transmission element 139 to the vane carrier 137, thus preventing the separation of the transmission element 139 from the vane carrier 137 during manipulations of the pump comprising such a device.

In Figure 8 can be seen a third embodiment of an element 201 according to the present invention, which is fixed with respect to the vane carrier, is resistant to frictional wear attributable to the radial movement of the transmission element and is incorporated in the body of the vane carrier 337 made from plastic or the like during the molding operation. The interposed element 201 is formed by two independent wings 203, 205 having substantially the same shape as those of the first and second embodiments and arranged in the mold, before the injection of the plastic, said wings being 13 secured to the body of the vane carrier during the solidification of the plastic.

The wings 203, 205 are arranged in the mold in such a way that, after the mounting of the vane carrier 237/transmission element 239 assembly, they are interposed between the body of the vane carrier 237 and the transmission element 239 in the direction of rotation of the transmission element 239.

The interposed element according to the third embodiment is, for example, manufactured from metal, from plastic reinforced with glass fibers or from ceramic.

It goes without saying that the present invention is not limited to a rotor with a single vane, the rotor according to the present invention being capable of comprising a plurality of vanes by virtue of a simple modification of the present invention by a person skilled in the art.

It also goes without saying that the pump according to the present invention may be driven by a camshaft with a thermal engine, but also by any device capable of supplying a rotational movement.

It likewise goes without saying that the pump according to the present invention forms at least one vacuum source, but is also capable of feeding liquid, for example fuel, to an engine.

The present invention applies particularly to the motor vehicle industry.

The present invention applies mainly to the brake industry and, more particularly, to brake boosting devices.

Claims

1. Rotor, comprising a transmission element, a vane carrier and at least one vane, said transmission element transmitting a torque to said vane carrier, wherein the vane carrier comprises interposed elements immovable radially with respect to the vane carrier and arranged in the region of bearing surfaces between the transmission element and the vane carrier in order to transmit the bearing force of the transmission element of the vane carrier, wherein said interposed elements are resistant to wear caused by the friction of the transmission element, the interposed elements comprise two parallel wings, the two wings are connected by means of a plate, the interposed elements are secured to a central rod carried by the vane carrier, and wherein the plate comprises an orifice, into which issue at least two tabs cooperating with the central rod carried by the vane carrier.

2. Rotor according to Claim 1, wherein the wings extend perpendicularly to the plate and on the same side of the plate.

3. Rotor according to Claim 1 or 2, wherein the wings are symmetrical with respect to a longitudinal axis of the plate.

4. Rotor according to any one of the preceding claims, wherein the plate comprises fastening means cooperating with second fastening means carried by the vane carrier.

Rotor according to Claim 4, wherein the fastening means carried by the plate comprise an orifice of smaller diameter, edged with a sleeve, and wherein the fastening means comprise a rod of larger diameter, carried by the vane carrier, said rod being equipped with an annular bead which projects on the periphery 15 0O C and is formed after the force mounting of the plate C around the rod, and wherein the sleeve is arranged between the bead and the transmission element after mounting.

6. Rotor according to the Claim 5, wherein the plate comes to bear on a bearing surface formed in the periphery of said rod perpendicularly to the axis of the rod. CI

7. Rotor according to any one of the preceding CClaims, wherein the transmission element is made from metallic material and the vane carrier is made from plastic.

8. Rotor according to the Claim 7, wherein the transmission element is produced from steel.

9. Rotor according to any one of the preceding Claims, wherein the interposed element is produced from metallic material.

Rotor according to the Claim 9, wherein the interposed element is produced from spring steel.

11. Rotor according to Claim 9 or 10, wherein the interposed element is produced by bending.

12. Rotor according to either one of Claims 5 or 6, wherein the fastening means carried by the plate of the interposed element are produced by stamping.

13. Rotor according to Claim 7 wherein the interposed elements are incorporated in the plastic vane carrier during the manufacture of the vane carrier by molding, the interposed elements being formed by wings arranged in the region of the bearing surfaces between the transmission element and the body of the vane carrier. 16

14. Pump, forming at least one vacuum source, comprising at least one rotor according to any one of the preceding Claims.

15. Pump according to Claim 14, wherein the element is driven by a camshaft.

16. Pump according to Claim 14, wherein the element is driven by an electric motor.

17. Pump according to Claim 14, wherein the element is driven by a pulley driven by a belt.

18. Method for manufacturing a rotor according to Claim 1, comprising the step of manufacturing the vane carrier by plastic molding, wherein it comprises, furthermore, the step of arranging the wings, before the injection of the plastic into the mold for manufacturing the vane carrier, in such a way that said wings are arranged in the region of the bearing surfaces between an element for the transmission of a torque and the vane carrier, and in such a way that they are made immovable from the body of the vane carrier during the removal of the vane carrier from the mold.

19. A rotor substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. A pump substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples. I 17 00 0 21. A method for manufacturing a rotor, the method Cy- being substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or D 5 examples. Shelston IP SAttorneys for: VHIT S.p.A. Vacuum Hydraulic Products Italy m c- 0