EP2131978B1 - Device and method for calibrating a sintered molded part - Google Patents

Description

The invention relates to a device for calibrating a sintered molded part with a helical toothing with a Kalibrierwerkzeug, comprising a lower punch for receiving the sintered molded part with a Unterstempelaußenverzahnung, a vertically movable and axially rotatably supported Oberstempel Oberstempelaußenverzahnung, and an axially rotatably supported die with a Matrizeninnenverzahnung and a A method for calibrating a sintered molded part with a helical toothing with a calibration tool, comprising a lower punch with a lower punch external teeth, a vertically movable and axially rotatably supported Oberstempel with Oberstempelaußenverzahnung, and an axially rotatably supported die with a Matrizeninnenverzahnung, after which the sintered molded part placed on the lower punch and is positioned on this, then the upper punch is lowered in the direction of the sintered molded part and thereby the sintered molded part and the lower part Pel are lowered in the direction of the die and thus the helical toothing of the sintered molded part is pressed into the matrix internal teeth.

From the US 7,025,929 B is a method for densifying the teeth of a gear with a helical toothing known. For this purpose, this is pressed after compacting the powder and the subsequent sintering with a punch through a die, which has on the inner surface of a gear complementary to the toothing. By pushing through the near-surface areas of the teeth are further compressed. The gear is moved only by axial, helical movement through the die. The die has a plurality of sub-matrices, which are separated by cutting discs

The DE 698 22 572 T2 describes an apparatus for adjusting the size of the tooth profiles of helical gears, comprising: a lower punch, wherein a gear blank having teeth formed thereon is adapted to be placed thereon; an upper punch vertically movable around the gear blank downward and a sizing measure adapted to engage inner peripheral teeth thereof with the gear blank pressed by the upper punch to adjust the tooth profiles of the gear blank in size. The lower punch has a first and a second lower punches, with the second lower punch set up is to carry a gear wheel blank which is placed thereon, in a non-rotatable manner and the first lower punch is axially rotatable about the second lower punch and has outer fringing teeth thereon, wherein the size adjustment dimension is axially rotatable and vertically movable, while their inner peripheral teeth with the outer peripheral teeth of the first lower punch, and wherein the upper punching means is axially rotatable and provided with outer peripheral teeth which engage with inner peripheral teeth of the size-adjusting gauge. Further, this DE-T2 describes a method for adjusting the size of tooth profiles of helical gears after a gear blank having teeth formed thereon is non-rotatably positioned on a lower punch, then the size of the tooth profiles of the gear blank by pressing the gear blank down with an upper one Punching means is set in a size adjustment dimension, while the teeth of the gear blank and outer peripheral teeth of the upper punching means with inner peripheral teeth of the size adjustment scale are engaged and - at the completion of the size setting step - the size setting from the engagement with the upper punching means and the gear blank by turning and lowering the size adjustment scale and Moving the upper punching means is released upward and the gear blank is removed.

JP09176701 describes a device for calibrating.

It is an object of the invention to provide a simple device for calibrating a sintered molded part with a helical toothing, as well as an easily feasible method.

This object is achieved independently by the fact that in the inventive device according to claim 1, the lower punch is supported only vertically movable, and in the inventive method according to claim 6, wherein the direction of movement of the lower punch is reversed after reaching a lower end position and the calibrated sintered compact is moved out of engagement of the female die of the die by the vertical movement of the lower punch.

The advantage here is that the movement of the tool can be simplified by the only vertical mobility of the lower punch, in which an additional drive device for a rotary movement of the lower punch, as is known from the prior art, can be dispensed with. It is also easier to carry out the storage of the die, since the discharge of the finished calibrated sintered component is carried out by an upward movement of the lower punch. As a result, it is possible to the supply and discharge devices the sintered component to and from the tool easier to do, since the supply of the blank takes place on a plane or at the same height as the discharge of the finished calibrated sintered component. It is thus easier to carry out an automation of the device or the method for calibrating a sintered molded part. In addition, no additional masses must be moved vertically, so that the energy balance of the device turns out cheaper.

It is further possible that the die is exclusively rotatably supported, whereby an additional drive means for lowering the die, as known and necessary from the prior art for the demolding of the sintered molded part, can be dispensed with, whereby a further simplification of the device is possible.

The upper punch of the calibration tool can be operatively connected to a guide unit, which sets the upper punch during the calibration process of the sintered molding in the die in a rotary motion, whereby a relative movement between the workpiece and the punch during calibration is avoided.

It is further possible to form the upper punch and / or the lower punch in one piece, which in turn a further simplification of the calibration tool can be achieved and thus the calibration tool can also be performed more cost-effectively.

The lower punch or the upper punch can form the drive device for the axial rotational movement of the die, which can be dispensed with an additional drive device for this purpose and also the synchronization of the movement of the die with the movement of the lower punch or upper punch is easier to perform. The rotational movement of the die can in this case be carried out by lowering the upper punch or the lower punch as a result of the engagement of the respective outer toothing with the inner toothing of the die.

According to an embodiment variant of the method, it is provided that an axial rotation of the upper punch is initiated even before the impact of the upper punch on the sintered molding or the blank, wherein the engagement position of the outer toothing of the upper punch is made in the internal toothing of the die by this rotation. It will be so achieved that the upper punch can be moved from any relative position to the die automatically in the engaged position, so that an additional vote of the movement of the upper punch and this synchronization movement does not have to be made.

It is also possible that the upper punch after lowering the sintered molded part on a contact surface of the die together with the lower punch by the upper punch does not rotate axially, so by moving together of the upper punch with the lower punch an entire compression of the sintered compact over its cross section - in axial Direction - is bidirectional, so not only a calibration of the teeth is feasible with the inventive method, but at the same time also the said total compression. It can thus be carried out with a single device, both the calibration and the compression of the sintered preform blank.

Again in order to avoid a relative movement between the sintered shaped part and the upper punch, it is possible, according to an embodiment variant of the method, to rotate the upper punch during the calibration process of the sintered molded part in the matrix and synchronously with the rotation of the die.

For a better understanding of the invention, this will be explained in more detail with reference to the following figures.

Fig. 1

eine erfindungsgemäße Vorrichtung in der offenen Einlegestellung für das Sinterformteil;

Fig. 2

die Vorrichtung nach Fig. 1 in der Kalibrierstellung.

Each shows in a highly schematically simplified representation:

Fig. 1

a device according to the invention in the open insertion position for the sintered molded part;

Fig. 2

the device after Fig. 1 in the calibration position.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, wherein the disclosures contained throughout the description are transmitted mutatis mutandis to the same parts with the same reference numerals or component names can. Also, the position information selected in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to a new position analogous to the new situation. Furthermore, individual features or combinations of features from the various exemplary embodiments shown and described can also represent separate, inventive or erfmdungsgemäße solutions.

The Fig. 1 and 2 show a device 1 for calibrating a sintered molded part 2 with a helical toothing 3 with a calibration tool 4 Fig. 1 the open position of the device 1, in which the sintered molded part 2 to be machined can be inserted into this device 1, whereas the Fig. 2 is the closed representation of the device 1, in which the sintered molded part 2 is calibrated in the calibration tool 4.

This device 1 is intended to calibrate bevel gears 3 on gears, sprockets or the like, that is, to improve the dimensional accuracy of these sintered moldings 2, in particular the helical gears 3, so the accuracy of the teeth. For this purpose, the sintered molded part 2, that is, for example, a gear, produced with an over-height, which may be present in the radial direction and optionally also in the axial direction, so that the sintered molded part 2 can be pressed both axially and radially to the final dimension this sintered molding 2.

By calibrating the surface roughness of the sintered molded part 2 is reduced, whereby the wear behavior of the sintered molded part 2 can be improved.

The device 1 comprises a lower punch receptacle 5 on which columns 6, 7 are supported. The columns 6, 7 serve on the one hand to hold the calibration tool 4 and on the other hand to guide the vertical movement of a punch 8. Furthermore, the columns 6, 7 can also be used to control the movement of the upper punch 8. For this purpose, the columns 6, 7 in this embodiment comprise four upper punch rotating elements 9-12. The maximum vertical movability of the upper punch 8 can be limited via the upper punch rotating element 10. The Oberstempelrotationselement 12 can be additionally used for a vertical support of the upper punch to avoid twisting of the upper punch 8. The lower punch holder 5 forms the control plane.

Furthermore, a die holder 13 for a die 14 is supported on these guide columns 6, 6. A lower punch 15 is supported in this embodiment by a lower punch support 16, which is supported on the lower punch holder 5.

The upper punch 8, the die 14 and the lower punch 15 form the calibration tool 4th

The upper punch 8 is supported vertically displaceable by an upper punch holder 17, this upper punch holder 17 is supported on the Oberstempelrotationselement 11 and during the downward movement of the upper punch 8 on the Oberstempelrotationselement 9 is moved to a stop between this and the Oberstempelrotationselement 10, as is apparent from Fig. 2 is apparent.

Between the upper punch 8 and the upper punch holder 16 a Oberstempelabstützung 18 is arranged, wherein at least partially between the Oberstempelaufnahme 16 and the Oberstempelabstützung 18 a bearing 19 may be formed or arranged.

In one embodiment variant, it is possible to replace the columns 6, 7 in each case by a single continuous column, in which case the upper punch holder 16 is supported so as to be vertically displaceable along these continuous columns.

The upper punch 8 has an upper punch outer toothing 21 at least in an end region 20 pointing to the lower punch 15.

The lower punch 15 has a lower punch outer toothing 23 at least in an end region 22 pointing towards the upper punch 8

On the other hand, the die 14 has an internal female toothing 24 in the region of a die opening 25, ie on an inner surface of this die opening 25. The Matrizeninnenverzahnung 24 is complementary to the helical teeth 3 of the sintered molded part 2 and further complementary to the upper punch outer teeth 21 of the upper punch 8 and the lower punch outer teeth 23 of the lower punch 15th

The sintered molded part 2 is in the illustration after the Fig. 1 and 2 shown as a simple component without any gradations etc. In the context of the invention, however, it is also possible to calibrate the helical toothing 3 of more complex sintered shaped parts 2.

Although the upper punch 8 and the lower punch 15 is integrally formed in the illustrated embodiment, these can also be designed in several parts for processing multi-stage sintered moldings 2 according to the gradation (s), wherein the individual stamp parts in the radial direction can be arranged sleeve-like one above the other, so a Component of the next component encased. However, the one-piece design of the upper punch 8 and the lower punch 15 is also possible for the production of multi-stage sintered moldings 2, but associated with higher tooling costs.

It is further possible that the lower punch 15 comprises a so-called core pin - not shown - which is arranged in the lower punch 15 in the axial direction extending centrally along a central axis, are pushed onto the sintered moldings 2, which have a corresponding recess in the middle, and These sintered moldings 2 are thus positioned over this core pin. The core pin can be integrally formed with the lower punch 15 or form a separate component. In the case of the arrangement of a core pin, the upper punch 8 has a corresponding recess into which the core pin can dip. It can also be arranged several core pins, in the event that sintered moldings 2 are processed with multiple openings in the axial direction. Accordingly, the upper punch 8 may have a plurality of recesses. The core pin (s) is or are in the insertion position for the sintered molded part 2 in the direction of the upper punch 8 via the die 14, so that the sintered molded part 2 can be pushed.

It goes without saying that the exact formation of the upper punch 8 and the lower punch 15 of the illustrated variant in Fig. 1 respectively. Fig. 2 can differ, since this is ultimately adapted to the geometry of the sintered molded part 2.

For easier insertion of the sintered molded part 2 in the die 14 is an end portion 26 of Die 14, which is directed to the upper punch 8, conically widening outwardly formed, as is made Fig. 1 is apparent.

The Fig. 2 shows the calibration tool 4 in the closed mold, ie, so that the upper punch 8 rests on the sintered molded part 2 and this sintered molded part 2 is in turn mounted on the lower punch 15. In the calibration position, the sintered molded part 2 dips into the die 14, so that the toothing of the sintered molded part 2 comes into contact with the female internal toothing 24 of the female mold 14 and thus the calibration of this helical toothing 3 of the sintered molded part 2 can be performed.

To this position after Fig. 2 To achieve both the upper punch 8 and the lower punch 15 are lowered in the vertical direction.

For the production of the sintered molded part 2, ie the calibration of the same, this sintered molded part 2 is placed in a first step on the lower punch 15 of the calibration tool 4, as is apparent from Fig. 1 is apparent. Thereafter, by vertical lowering of the upper punch 8, the closing movement is initiated, the upper punch 8 can be placed in a rotational movement before striking the sintered molded part 2, so as to produce the exact relative position of the upper punch outer teeth 21 of the upper punch 8 with the female teeth 24 of the die 14, so that the immersion of the upper punch external teeth 21 of the upper punch 8 in the female die 24 of the die 14 can be easily ensured.

After the upper punch 8 has hit the sintered shaped part 2 and thus the calibration tool 4 is closed, the sintered shaped part 2 together with the lower punch 15 are moved together by vertical movement of the upper punch 8 in the calibration position, wherein the lower punch 15 moves further down as well as the upper punch 8 and thus on the one hand, the upper punch outer teeth 21 of the upper punch 8 with the female teeth 24 of the die 14 engages.

As a result of the downward movement of the lower punch 15, via the lower punch outer toothing 23, the die 14 is brought into a horizontal, ie axial, rotational movement by engagement of this lower punch outer toothing 23 with the female die 24 of the die 14. offset, so that the die 14 rotates about the lower punch 15. By this rotational movement, it is possible to calibrate helical sintered moldings 2. The drive of the die 14 thus takes place in this embodiment via the lower punch 15, ie its downward movement or its vertical movement.

The rotational movement of the upper punch 8 is stopped after the setting of the synchronous position, ie the position in which a trouble engagement of the Oberstempelaußenverzahnung 21 with the Matrizeninnenverzahnung 24 of the die 14, so that this upper punch 8 moves exclusively vertically in this phase of the manufacturing process and thus a compression of the entire sintered molded part 2 is made possible.

During the actual calibration process of the helical gearing 3 of the sintered molded part 2, it being noted that the calibration by the excess of the sintered molded part 2 also corresponds to a compaction process - the upper punch 8 is rotated again by its own guide unit, so that after the sintered shaped part 2 rotates by the downward movement of the lower punch 15, a relative movement between the sintered molded part 2 and the upper punch 8 is avoided.

After completion of the calibration process, ie, when the lower punch 15 has reached its lower end position, the direction of movement is reversed, the die 14 remains unchanged with respect to their horizontal arrangement in the device 1 and the lower punch 15 moves vertically upwards, whereby the upper punch 8 itself also moved up. Optionally, this upward movement of the upper punch 8 by an additional drive means which is operatively connected to the upper punch 8 are supported, so that therefore the calibration tool 4 already opens during the upward movement. The vertical upward movement of the lower punch 15, the sintered molded part 2 from the engaged position, ie the calibration position, in the die 14, moved and released from the die 14, wherein the die 14 also rotates during upward movement, but in the opposite direction, and can after opening the calibration tool 4, wherein the open position of the insertion position after Fig. 1 may correspond, removed from the engagement of the lower punch 15 and removed.

In one embodiment of the invention, it is possible that the die 14 a lowering movement performs when the upper punch 8 and the lower punch 15 are fixed in their relative position to each other to achieve a compaction, however, the embodiment in which the die performs an exclusive rotational movement, is preferred.

The embodiments show possible embodiments of the device 1 for calibrating a sintered molded part 2 with a helical toothing 3, it being noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments are possible with each other and this possibility of variation due to the teaching on technical action by objective invention lies in the ability of those skilled in this technical field. So are all conceivable embodiments, which are possible by combinations of individual details of the illustrated and described embodiment variant, includes the scope of protection.

For the sake of order, it should finally be pointed out that for a better understanding, the device 1 has been shown partially unevenly and / or enlarged and / or reduced in size.

The problem underlying the independent inventive solutions can be taken from the description.

Above all, the individual in the Fig. 1 ; 2 shown embodiments form the subject of independent solutions according to the invention. The relevant objects and solutions according to the invention can be found in the detailed descriptions of these figures.

REFERENCE NUMBERS

1

contraption

2

Sintered compact

3

helical teeth

4

calibration

5

Lower punch recording

6

pillar

7

pillar

8th

upper punch

9

Upper punch rotation element

10

Oberstempekotationselement

11

Upper punch rotation element

12

Upper punch rotation element

13

die holder

14

die

15

lower punch

16

Lower punch support

17

Punch recording

18

Upper punch support

19

camp

20

end

21

Upper punch external toothing

22

end

23

Lower punch external toothing

24

Matrizeninnenverzahnung

25

die opening

26

end

Claims (11)

1. Device (1) for calibrating a sintered moulded part (2) with an angular toothing (3) by means of a calibrating tool (4), comprising a lower punch (15) for mounting the sintered moulded part (2) with a lower punch external toothing (23), a vertically movable and axially rotatably mounted upper punch (8) with an upper punch external toothing (21), as well as an axially rotatably mounted die (14) with a die internal toothing (24), with the internal toothing (24) being embodied complementarily to the angular toothing (3) of the sintered moulded part and further complementarily to the lower punch external toothing (23) of the lower punch (15), characterised in that the lower punch (15) is mounted so as to move only in vertical direction.
2. Device (1) according to claim 1, characterised in that the die (14) is mounted to be only rotatable.
3. Device (1) according to claim 1 or 2, characterised in that the upper punch (8) is actively connected with a guiding unit, which sets the upper punch (8) into a rotary movement during the calibrating process of the sintered moulded part (2) in the die (14).
4. Device (1) according to one of claims 1 to 3, characterised in that the upper punch (8) and/or the lower punch (15) are designed in one piece.
5. Device (1) according to one of claims 1 to 4, characterised in that the lower punch (15) or the upper punch (8) is the driving device for the axial rotational movement of the die (14).
6. Method for calibrating a sintered moulded part (2) with an angular toothing (3) by means of a calibrating tool (4), comprising a lower punch (15) with a lower punch external toothing (23), a vertically movable and axially rotatably mounted upper punch (8) with an upper punch external toothing (21), as well as an axially rotatably mounted die (14) with a die internal toothing (24), according to which the sintered moulded part (2) is placed onto the lower punch (15) and positioned on the latter, then the upper punch (8) is lowered in the direction of the sintered moulded part (2), and in this way the sintered moulded part (2) and the lower punch (15) are lowered in the direction of the die (14), and thereby the angular toothing (3) of the sintered moulded part (2) is pressed into the die internal toothing (24), characterised in that the lower punch (15) is moved only in vertical direction and the direction of movement of the lower punch (15) is reversed after reaching a lower end position and the calibrated sintered moulded part (2) is moved by the vertical movement of the lower punch (15) upwards out of engagement with the die internal toothing (24) of the die (14).
7. Method according to claim 6 characterised in that the axial rotation of the die (14) and thereby the calibration of the sintered moulded part (2) are initiated by lowering the lower punch (15) with the sintered moulded part (2).
8. Method according to claim 6, characterised in that the axial rotation of the die (14) and thus the calibration of the sintered moulded part (2) is initiated by lowering the upper punch (8).
9. Method according to one of claims 6 to 8, characterised in that an axial rotation of the upper punch (8) is initiated before the upper punch (8) hits the sintered moulded part (2).
10. Method according to one of claims 6 to 9, characterised in that the upper punch (8) after the lowering of the sintered moulded part (2) onto a bearing surface of the die (14) together with the lower punch (15) by means of the upper punch (8) does not rotate axially and the sintered moulded part (2) is compacted in this way bidirectionally over its entire cross section in axial direction.
11. Method according to one of claims 6 to 10, characterised in that the upper punch (15) is rotated during the calibrating process of the sintered moulded part (2) in the die (14).

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