EP2215364B1 - Dye, sintered rotor and sintering method - Google Patents

Description

The invention relates to a die for sintering a sintered rotor according to the preamble of claim 1. The invention further relates to a method for producing such a sintering rotor. The invention further relates to a sintering rotor produced by means of the die according to such a method and a pump having such a sintering rotor.

It is possible to produce sintering rotors with a wing receiving slot which is open at one end face of the rotor main body. The publication WO 2005/001293 A1 discloses a rotor made of sintered metal of a rotary lobe pump with a cup-shaped main body and a central bearing element of the base body of this bearing element of a directly from the bottom emanating cylindrical foot portion and a subsequent connecting claw portion. The publication GB 1 340 486 discloses improvements to forging equipment. Document JB 59107003 discloses how to improve the constitution of plunger punches.

The object of the invention is to simplify the production of a sintered rotor for a pump, in particular a vacuum pump, with a rotor main body having a wing receiving portion with at least one wing receiving slot and at least two sintered bearing sections.

The object is achieved with the features of claim 1. The dependent subclaims relate to further developments of the inventive concept in the sense of the task.

The sintering rotor is a sintered rotor. During sintering, a powdery or fine-grained material is compressed by the effect of pressure and temperature, with the grains joining together at their surfaces. By the bearing body of the conventional sintered rotors open wing receiving slot is closed. The two bearing sections each have substantially the shape of a straight circular cylinder jacket.

According to an essential aspect of the invention, the sintering rotor is pressed longitudinally, that is to say all movements of punches in the sintered metal powder transfer and compacting of the sintered metal powder in a die take place in the longitudinal direction of the sintering rotor, ie in the direction or parallel to the axis of rotation of the sintering rotor.

A preferred embodiment of the sintering rotor is characterized in that the bearing body and the wing receiving portion have the same outer diameter. The bearing body and the wing receiving portion have the outside substantially the shape of a straight circular cylinder jacket.

Another preferred embodiment of the sintering rotor is characterized in that the bearing body has the shape of a ring. Through the ring unwanted spreading of the rotor body is prevented in the wing receiving portion.

A further preferred embodiment of the sintering rotor is characterized in that the ring has a substantially rectangular cross-section. The outside of the ring forms a bearing surface for rotatably supporting the sintering rotor in a pump housing part.

A further preferred embodiment of the sintering rotor is characterized in that the rotor base body in the wing receiving portion has longitudinal grooves for sinking or receiving press ridge in the area of the wing receiving slot. The longitudinal grooves extend in a parting plane between webs, which are provided on a die, and a punch whose function will be explained below.

In a die for sintering a previously described sintered rotor with longitudinal webs to form the wing receiving slot, the above-stated object is achieved in that the longitudinal webs are limited by a circumferential shoulder. The circumferential paragraph creates an annular space for the production of the bearing body.

A preferred embodiment of the die is characterized in that the longitudinal webs and the shoulder are integrally formed on the die. Alternatively, it is possible to produce the webs and the heel with the aid of punches.

In a method for producing a sintering rotor described above, with the aid of a previously described die, the above-described object is achieved in that the die is filled from a filling side with sintered metal powder, which is compacted by means of a plurality of punches in the longitudinal direction of the sintering rotor are movable to exert a compression force or a compression pressure on the sintered metal powder in the die. As a longitudinal direction, the axis of rotation or axis of rotation of the sintering rotor is referred to. The die can be made in one or more parts and preferably has a tubular or circular cylindrical shape. A preferred embodiment of the method is characterized in that a part of the compression force or the compression pressure of the filling side opposite side is applied. As a result, the generation of an undercut on the rotor base body is made possible in a simple manner.

A further preferred embodiment of the method is characterized in that the die, based on the Erdschwerkraft, is filled from above with sintered metal powder, and that the majority of the compression force or the compression pressure is applied from below. This simplifies filling.

Another preferred embodiment of the method is characterized in that the die is filled from the side having the shoulder. This simplifies the creation of the undercut.

A further preferred embodiment of the method is characterized in that the die is closed after filling with at least one filling side punch. In this case, a relatively low compression force is applied to the sintered metal powder.

A further preferred embodiment of the method is characterized in that the sintered metal powder is displaced in the matrix by means of a plurality of punches. The displacement of the sintered metal powder is also referred to as powder transfer and serves to bring the sintered metal powder in the form or shape that should have the finished sintering rotor.

Another preferred exemplary embodiment of the method is characterized in that the punches for moving the sintered metal powder are moved from the filling side into the die. Preferably, a plurality of partially executed hollow punch in a further hollow punch executed or reciprocally guided back and forth.

A further preferred embodiment of the method is characterized in that the displaced sintered metal powder in the die is compacted by means of a plurality of punches. Preferably, the same punches are used for compacting as for moving the sintered metal powder.

A further preferred exemplary embodiment of the method is characterized in that the punches for compacting the sintered metal powder are moved mainly into the die from the side opposite the filling side. Almost the entire compaction force is applied by the side opposite the filling side.

A further preferred embodiment of the method is characterized in that a punch for compressing the bearing body is moved from the filling side into the die. This movement is significantly smaller than the compression movement from the opposite side.

The invention also relates to a pump, in particular a vacuum pump, with a sintering rotor described above.

Figur 1

eine perspektivische Darstellung eines erfindungsgemäßen Sinterrotors;

Figur 2

den Sinterrotor aus Figur 1 im Längsschnitt;

Figur 3

den Sinterrotor aus Figur 1 in einem weiteren Längsschnitt durch den Flügelaufnahmeschlitz;

Figur 4

eine Seitenansicht des Sinterrotors aus Figur 3 von rechts;

Figur 5

eine Seitenansicht des Sinterrotors aus Figur 3 von links;

Figur 6

eine Matrize zur Herstellung des Sinterrotors aus den Figuren 1 bis 5 im Horizontalschnitt;

Figur 7

die Ansicht eines Schnitts entlang der Linie VII-VII in Figur 6;

Figuren

schematische Darstellungen eines Verfahrens zum Herstellen eines

8 bis 13

Sinterrotors, wie er in den Figuren 1 bis 5 dargestellt ist, in verschiedenen Verfahrensschritten und

Figur 14

die Ansicht eines Querschnitts an einer Stelle XIV in Figur 1.

Further advantages, features and details of the invention will become apparent from the following description in which, with reference to the drawings, various embodiments are described in detail. Show it:

FIG. 1

a perspective view of a sintered rotor according to the invention;

FIG. 2

the sintering rotor FIG. 1 in longitudinal section;

FIG. 3

the sintering rotor FIG. 1 in a further longitudinal section through the wing receiving slot;

FIG. 4

a side view of the sintering rotor FIG. 3 from the right;

FIG. 5

a side view of the sintering rotor FIG. 3 from the left;

FIG. 6

a die for producing the sintered rotor from the FIGS. 1 to 5 in horizontal section;

FIG. 7

the view of a section along the line VII-VII in FIG. 6 ;

characters

schematic representations of a method for producing a

8 to 13

Sintered rotor, as in the FIGS. 1 to 5 is shown in various process steps and

FIG. 14

the view of a cross section at a point XIV in FIG. 1 ,

The sintering rotor according to the invention is part of a vacuum pump, in particular a vane pump, which serves, for example, to generate a vacuum in a vacuum chamber of a brake booster. The sintering rotor is driven, for example, via a drive shaft and guides a vane, which is rotatably arranged within a cam ring. If the sintering rotor rotates about its axis of rotation, then it comes in a suction chamber to an increase in volume, which causes a suction of a working medium, in particular of air or an air-oil mixture in the suction chamber. At the same time it comes in a pressure chamber to a volume decrease, which causes a conveying of the working fluid from the pressure chamber.

In the FIGS. 1 to 5 Rotor body 1 is shown in different views. At one end, the rotor body 1 has a coupling element 2, which is designed, for example, as a two-plane and for driving coupling of the rotor body 1 and the drive shaft (not shown).

The coupling element 2 is followed by a bearing section 4, which has the shape of a straight circular cylinder jacket on the outside. The bearing portion 4 is integrally connected to a wing receiving portion 5, which also has substantially the shape of a straight circular cylinder which is interrupted in the longitudinal direction by a wing receiving slot 6. The wing receiving slot 6 is bounded on one end side by the bearing portion 4, which has a smaller diameter than the wing receiving portion 5.

At its opposite end of the wing receiving slot is closed by a bearing body 10 which is integrally connected to the rotor body 1. The bearing body 10 has substantially the shape of a ring with a rectangular cross-section. The bearing body 10 has radially on the outside a further bearing portion 12, which has substantially the shape of a straight circular cylinder. The further bearing section 12, together with the bearing section 4, enables a particularly stable mounting of the sintering rotor, which is designated as a whole by 20. The wing section 5 extends between the two bearing sections 4 and 12. In the area of the wing receiving slot 6, the bearing body 10 has two groove-like depressions 15, 16.

In the sectional views of FIGS. 2 and 3 it can be seen that the rotor base body 1 has a central oil feed channel 22 in the bearing section 4, which extends in the direction of a longitudinal or rotational axis 21 of the rotor main body 1 or rotor 20. The central oil feed channel 22 is connected via a connecting channel 23 with a transverse channel 24 in connection, which opens radially outward into a formed on the bearing portion 4 bearing surface. The rotor 20 comprises in the wing receiving section 5 a central recess 26 which is closed towards the bearing section 4 and open to the bearing body 10.

In the FIGS. 6 and 7 For example, a die 30 for making the sintering rotor 20 is shown in two different views. The die 30 has a tubular, cylindrical base body 31 which has two longitudinal webs 32, 33 inside, which serve to form the wing receiving slot 6 in the rotor base body 1. The two longitudinal webs 32, 33 are integrally formed on the tubular base body 31 of the die 30. At the in FIG. 7 upper end of the die 30, the longitudinal webs 32, 33 bounded by a shoulder 34, which forms an annular space 35 to form the bearing body 10.

In the FIGS. 8 to 13 the die 30 is shown simplified and schematically in the manufacture of the sintering rotor 20, in particular during filling, displacement and compression. Identical parts are provided with the same reference numerals.

In FIG. 8 the die 30 is shown during filling. Sintered metal powder 41 is introduced into the interior of the die 30 via a connecting piece 40. In the die 30, a filling volume 42 is limited by punches 44, 45, 46, which are retracted from below, that is, from the side opposite the filling side, into the die 30. The punch 44 has the shape of a straight solid cylinder having at its free end a mandrel 47 which has a smaller outer diameter than the punch 44.

The punch 44 is guided in a further punch 45 movable back and forth, which is hollow inside. The punch 45 in turn is guided in a further punch 46 movable back and forth, which is also hollow inside. Since the punch 44 centrally in the. Center of the die 30 is arranged, the punch 44 is also referred to as a central punch. The punch 45 is also called a middle punch. The punch 46 is also referred to as an outer punch.

The area of the later wing receiving slot is in the area outside the webs or longitudinal webs (32, 33 in the FIGS. 6 and 7 ) of the die 30 is filled with sintered powder, as indicated at 48 and 49. The areas 48, 49 filled with sintered metal powder are delimited in the longitudinal direction, that is to say parallel to the axis of rotation of the sintering rotor, at the bottom by the stamp 46 and at the top by the annular space 35 which is defined by the shoulder (34 in FIG FIG. 7 ) at the end of the longitudinal webs (32, 33 in FIG. 7 ) of the die 30 is formed.

In FIG. 9 the die 30 is shown before or at the start of a displacement or a transfer of the sintered metal powder 42 in the die 30. The die 30, which is already closed at the bottom by the punches 44, 45 and 46, is closed at the top, ie at its filling-side end, by three filling-side punches 51, 52, 53 prior to the start of the powder transfer. The stamp 51 is arranged centrally in the middle and is therefore also referred to as a central punch 51. The punch 52, which is also referred to as a middle punch, is hollow inside for receiving and guiding the central punch 51. The outer punch 53 is designed to receive the punch 52 with the punch 51 inside also hollow.

In powder transfer, the in FIG. 10 is shown, the filling-side central punch 51 and the filling-side central punch 52 move into the filling volume or transfer volume 42, that is, downwards. At the same time, the lower central punch 44 and the lower middle punch 45 move out of the filling volume 42, that is also downwards.

In FIG. 11 the end of the powder transfer is shown. At the end of the powder transfer, the filling-side punches 51 and 52 are retracted beyond the center of the die 30 into the filling volume 42. The lower punches 44 and 45 are each arranged only with their tip in the die 30. The outer punches 46 and 53 have their position until the end of the powder transfer in FIG. 11 not changed.

In the Figures 12 and 13 the start and the end of a compression process are shown, in which the filling volume 42, preferably under the effect of temperature, is compressed to the final shape of the sintering rotor 20. In FIG. 12 It is indicated that all three lower punches 44 to 46 are moved far into the die 30 during the compression. In this case, the filling-side punches 51, 52 move upwards. At the same time, the filling-side outer punch 53 moves slightly downward to compress the annulus 35 to form the bearing body. Until the end of the compression in FIG. 12 The filling-side outer punch 53 and the lower punch 44 to 46 move further toward each other. At the same time, the filling-side punches 51 and 52 continue to move upwards.

The present invention makes it possible in a simple manner to produce a sintered rotor with two bearing points made of sintered metal. A significant advantage is that the wing receiving slot (6 in FIG. 1 ) is completed or realized as a tool. The second bearing section (12 in FIG. 1 ) is arranged close to the final shape of the press blank. By the method according to the invention the combination of a tool falling or falling, closed at the end by a bearing ring wing receiving slot is made possible while minimizing the cutting volume. The sintering rotor according to the invention is longitudinal to the axis of rotation (21 in FIG. 3 ) pressed the sintering rotor, as in the Figures 12 and 13 is shown.

In FIG. 14 is a cross section at the point XIV in FIG. 1 shown. In the cross-section can be seen a part of the wing receiving slot in the wing receiving portion 5 of the rotor main body 1. The contour of the wing receiving slot 6 in the rotor base body 1 is generated radially outwardly by the web 33, which is formed on the die 30. Radially inside the wing slot 6 is generated by the punch 52, which moves into the die 30 during powder transfer.

The parting plane between the punch 52 and the longitudinal webs 33 is indicated by a line 60. At the ends of the parting plane 60 in each case a longitudinal groove 61, 62 is recessed in the rotor base body 1. The longitudinal grooves 61, 62 are used to record in the vane slot 6 resulting in compression of the sintered metal powder. The burr is also referred to as a tool cutting burr.

By sinking the Werkzeugtrenngrats in the longitudinal grooves 61, 62, an undesirable jamming of a wing of the vacuum pump in the wing receiving slot 6 can be prevented without the sealing effect between the wing and wing receiving slot is impaired.

By closed at the ends of the sintering rotor 20 geometry of the wing receiving slot 6, a greater dimensional stability can be obtained, since an undesirable spreading of the wing receiving slot is prevented. In addition, an additional operation calibration can be saved in the powder metallogical manufacturing process. <B><u> REFERENCE LIST </ u></b> 1 Rotor body 46 stamp 2 coupling element 47 mandrel 4 bearing section 48 Area 5 Wing receiving section 49 Area 6 Wing receiving slot 51 stamp 10 bearing body 52 stamp 12 bearing section 53 stamp 15 deepening 60 line 16 deepening 61 longitudinal groove 20 sintered rotor 62 longitudinal groove 21 axis of rotation 22 oil feed 23 connecting channel 24 Querkanal 26 recess 30 die 31 body 32 longitudinal web 33 longitudinal web 34 paragraph 35 annulus 40 Support 41 Sintered metal powder 42 Filling volume 44 stamp 45 stamp

Claims (18)

1. Die for sintering a sintered rotor for a pump, in particular a vacuum pump, comprising a basic rotor body (1), which has a sintered bearing section (4) and a vane receiving section (5), which comprises at least one vane receiving slot (6), the vane receiving slot (6) being delimited by a bearing body (10), which is connected in one piece to the sintered basic rotor body (1) and has a further sintered bearing section (12), with longitudinal webs (32, 33) for forming the vane receiving slot (6), characterized in that the longitudinal webs (32, 33) are delimited by a peripheral offset (34).
2. Die according to Claim 2, characterized in that the longitudinal webs (32, 33) and the offset (34) are integrally formed on the die (30).
3. Method for producing a sintered rotor (20) with the aid of a die (30) according to Claim 1 or 2, characterized in that the die (30) is filled from a filling side with sintered metal powder, which is compacted with the aid of a number of rams (44-46, 51-53), which are movable in the longitudinal direction of the sintered rotor (20), in order to exert a compacting force or a compacting pressure on the sintered metal powder in the die (30).
4. Method according to Claim 3, characterized in that part of the compacting force or the compacting pressure is applied from the side opposite from the filling side.
5. Method according to Claim 4, characterized in that the die (30) is filled with sintered metal powder from above, with respect to the Earth's gravitational force, and in that part of the compacting force or the compacting pressure is applied from below.
6. Method according to one of Claims 3 to 5, with a die (30) according to Claim 6 or 7, characterized in that the die (30) is filled from the side that has the offset (34).
7. Method according to Claim 6, characterized in that, after filling, the die (30) is closed by at least one ram (51-53) on the filling side.
8. Method according to Claim 6 or 7, characterized in that the sintered metal powder is displaced in the die (30) with the aid of a number of rams (51-53), in particular all the rams (44-46; 51-53).
9. Method according to Claim 8, characterized in that the rams (51-53) for displacing the sintered metal powder are moved into the die (30) from the filling side.
10. Method according to Claim 8 or 9, characterized in that the displaced sintered metal powder is compacted in the die (30) with the aid of a number of rams (44-46, 51-53).
11. Method according to Claim 10, characterized in that the rams (44-46) for compacting the sintered metal powder are moved into the die primarily from the side opposite from the filling side.
12. Method according to Claim 11, characterized in that a ram (53) for compacting the bearing body (10) is moved into the die (30) from the filling side.
13. Sintered rotor, produced by a method according to one of Claims 3 to 12, with the aid of a die according to Claim 1 or 2.
14. Sintered rotor according to Claim 13, characterized in that the bearing body (10) and the vane receiving section (5) have the same outside diameter.
15. Sintered rotor according to either of Claims 13 and 14, characterized in that the bearing body (10) has the form of a ring.
16. Sintered rotor according to Claim 15, characterized in that the ring has a substantially rectangular cross section.
17. Sintered rotor according to one of Claims 13 to 16, characterized in that the basic rotor body (1) has in the vane receiving section (5) longitudinal grooves (61, 62) for receiving flash in the region of the vane receiving slot (6).
18. Pump, in particular a vacuum pump, comprising a sintered rotor (20) according to one of Claims 14 to 17.

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