KR101304629B1 - External part of a switchable bucket tappet - Google Patents

Abstract

Along with substantial components such as webs 9 and 18, there is provided an outer portion 1 of a switchable bucket tappet which is formed in part by the metal injection molding method (MIM) to a near final contour. Thus, an outer part 1 is provided which can be manufactured inexpensively. Post-cutting treatment is generally unnecessary. In addition, a separate sheet metal part for forming the hydraulic medium channel can be omitted.

Metal injection molding method, web, bucket tappet, outer part

Description

EXTERNAL PART OF A SWITCHABLE BUCKET TAPPET}

The present invention relates to an outer part of a switchable bucket tappet for a valve train of an engine, the outer part having a hollow cylindrical protective part receivable in a guide bore of a cylinder head of the engine by an outer shell, the cam side end of the protective part. Is limited by the base as the cam operating surface, the guide bush extending in a direction away from the cam from the inner edge of the base extends with the bore for the inner part of the bucket tappet, the protective part extending in diameter through the outer part. And connected with the guide bush by a first web axially extending from the bottom of the base, within the web there is provided a guide bore for at least one sliding connection means, the radial side of the first web being the sheath of the protective part. Feed bore for the hydraulic medium fed from the first channel starting from the first inlet at By is cut laterally.

The outer part for the switchable bucket tappet is described in DE 43 14 619 A1, which is considered to be a general type. The outer part is produced, for example, by extrusion technology or by cutting. It can be seen that inside the outer part an additional sheet metal part is provided for the formation of a hydraulic medium channel for supplying the hydraulic medium to the connecting means and the hydraulic play compensation element. The sheet metal part must be welded in a complex manner with the inner skin of the protective part of the outer part and sealed there. The endothelial must be post-processed to ensure a seal. Overall, the manufacturing cost for the outer part is unnecessarily high, resulting in an unnecessarily high cost in mass production.

It is therefore an object of the present invention to achieve an external part of the mentioned type in which the disadvantages cited are eliminated.

According to the invention, this object is achieved by manufacturing the outer part in a single piece by means of a metal injection molding method (MIM) or precision casting.

This effectively eliminates the above disadvantages. The outer part is preferably provided with the whole part, such as a web, channel, etc., by a metal injection molding method or by precision casting.

In the case of the above-described metal injection molding method (MIM), which is well known to those skilled in the art, the freedom of plastic injection molding in component construction is combined with the advantages of powder metallurgy, that is, a wide range of materials with very small tolerances. Particularly preferably, undercutting, hollow chambers, screws and the like can be formed at one time during metal injection molding. Those skilled in the art here employ slide techniques and / or core extraction techniques.

The metal injection method can also preferably be implemented in conventional plastic injection molding machines. Post-cutting is omitted or minimized. It is also clear that the outer part is provided without cracking after completion according to the injection molding technique and includes good rigidity. In some cases, preferably, the wall thickness may be provided at 1 mm or less, which preferably affects the vibrating valve train mass as well as to the total mass of the outer part.

 Basically the manufacture of the outer part can also be realized using a disposal core, which can be made of plastic, for example, and the removal of the core is also by thermal decomposition and evaporation.

The manufacturing cost is reduced by eliminating the post-cutting step and the sheet metal part.

In a refinement of the invention an inner part of the switchable tappet is arranged inside the guide bush, and the bucket tappet is provided with a hydraulic play compensation device. In order to provide the hydraulic medium to the device, another inlet of the sheath of the protection is provided opposite the diameter at the first inlet of the sheath of the protection, through which the hydraulic medium can be guided to the play compensation element. The two inlets face the additional web outside the radius, the additional web intersecting the first web with the guide bore, preferably at right angles in plan view.

In a specific embodiment of the invention a ring part formed as a support for at least one lost motion spring may be mounted to the web from below. For better guidance of the spring, the outer edge of the ring part is provided with a collar projecting away from the cam.

According to another preferred configuration of the invention the first channel extends obliquely through the bucket tappet from the first inlet to the front of the guide bore with the connecting means. By allowing other channels to be molded directly into the additional web, the other channels cut the bore of the guide bush perpendicular to the axial line of the outer part.

It is preferable when longitudinal grooves are provided in the shell of the guard at each inlet. The longitudinal grooves should be in communication with the conduits which respectively cut the guide bores of the cylinder head. Thus, the first and second channels are always supplied with hydraulic medium or expensive longitudinal grooves need not be used in the guide bore of the cylinder head.

The hydraulic medium may be guided directly to the at least one connecting means and the hydraulic play compensation element, preferably with the removal of the storage space presented in the background. However, it is also possible for each segment type storage space for the hydraulic medium to be provided at the bottom of the base respectively.

In addition, the shell of the protection part on the side of each inlet from the end is provided with lugs protruding in the cam direction. The lug gives a sufficiently high sealing gap for the hydraulic medium guided through the cylinder head when the outer part is inserted into the guide bore of the outer part. Therefore, hydraulic medium loss is reduced.

It is also proposed that the base of the outer part is lowered outside of the cam operating face. This has the advantage of, for example, external partial reinforcement. The skilled person is thus able to form the outlet opening in a suitable, preferably metal injection molding method in the base region of the groove in order to prevent the accumulation of hydraulic medium in the achieved roof shaped groove.

The base of the outer portion can be made cylindrically convex in the cam movement direction so that the diameter of the outer portion can be made smaller. The skilled person selects the width of the recesses mentioned above so that in any case the cam contact is realized over the entire width.

Preferably two large stroke cams extending from both sides of the guide bush can contact the base of the outer part.

 In addition, the external portion for the switchable bucket tappet with the aforementioned base lowered in the form of a roof is generally provided or considered to be manufactured by conventional extrusion techniques or extraction techniques or by cutting, rather than by metal injection molding methods. can see. As a connecting means, a known slide set or at least one slide is provided, which slide set or slide is preferably displaced in one direction by hydraulic medium pressure and in another direction by the force of at least one mechanical spring. .

Hereinafter, the present invention is described in more detail with reference to the drawings.

1 is a spatial view of the outer part according to the invention.

2 is a longitudinal sectional view cut along the additional web of the outer part;

3 is another view of the outer part with a separate ring part as a spring system.

4 is a longitudinal sectional view showing the longitudinal section of the region of the additional web of the outer part obliquely from the bottom;

5 is a ring part shown in FIG.

1 to 4 show the outer part 1 for the switchable bucket tappet, wherein the entire part of the bucket tappet is preferably provided by a metal injection molding method (MIM) or alternatively by precision casting. .

The outer part 1 has a hollow cylindrical protective part 2 which can be arranged in the receiving bore of the cylinder head via the outer shell 3. The cam side end 4 of the protective part 2 is limited by the base 5 as the cam operating surface that is cylindrically convex in the cam movement direction.

The guide bush 7 extends with the bore 8 in a direction away from the cam from the inner edge 6 of the base 5. Within the bore 8 an internal part of the switchable bucket tappet can be arranged. However, the bucket tappet does not necessarily have a hydraulic play compensation device.

The first web 9 extends axially from the bottom of the base 5 in diameter through the outer part 1. The first web 9 has a guide bore 10, in which at least one connecting means capable of hydraulically driving in the displacement direction can be arranged. In this case, as shown in FIG. 3, the guide bore 10 is cut by the first channel 13 for the hydraulic medium on the radial side 11. The first channel starts from the first inlet 14 in the shell of the protective part 2 and is integrally manufactured by the metal injection molding method. The first channel 13 extends obliquely in the direction of the guide bore 10 through the outer part 1.

In addition, the first inlet 14 is in flow connection with the longitudinal groove 16 in the shell 3 of the protector 2. Similarly, the second inlet 15 facing in diameter with the first inlet 14 is connected with the other longitudinal groove 17. Each longitudinal groove 16, 17 communicates with a feed bore for the hydraulic medium cutting the guide bore of the cylinder head for the outer part 1. Thus, hydraulic medium supply is possible over all stroke stages of the outer part 1.

The second channel 14a shown in FIGS. 2 and 4 starts from the second inlet 15 directly through the additional web 18. The second inlet 15 joins the bore 8 radially inwards and is used to supply hydraulic medium to a hydraulic play compensation element disposed in an inner part, not shown. The second channel 14a is preferably likewise formed during the metal injection molding process.

On the webs 9, 18 that are "crossed" perpendicularly in plan view, the ring part 27, which is visible from the bottom in FIG. 5, is arranged so as not to tilt. The ring part 27 has a collar 29 protruding from the outer edge 28, in a direction away from the cam (the ring part can rotate according to FIG. 5). The ring component 27 may be equipped with a lost motion spring or a spring package. The collar 29 is used to center the lost motion spring.

The base 5, shown lowered outside the cam operating surface, is another important part of the outer part 1 described here. Two upper edges 19, 20 in the form of bow demonstrations of the base 5, which also run through the outer part 1, face equidistantly to the longitudinal central plane (FIG. 1). The upper edge is, for example, as shown in FIG. 1, two recesses 21, 22 facing in diameter are formed as the guide bush 7 is slightly cut and descends in the form of a roof on the additional web 18. . As the "falling" of the base 5 has a reinforcing effect on the entire outer part 1, the outer part 1 may be thinner in some cases.

In addition, as shown in the figure, two lugs 23, 24 protrude above the base 5 in the shell 3 at the sides of each inlet 14, 15. The lug “seals” the conduit in the guide bore of the cylinder head when the outer part 1 inserts in a direction away from the cam.

Thus, the outer part 1, which is preferably manufactured by the metal injection molding method (MIM), together with the channels 13, 14a formed in a single piece, and the two webs 9, 18 intersected when virtually extended, are provided. It is relatively inexpensive compared to background technology. In most cases, additional measures such as post-treatment or welding may be omitted. It is of course also possible for the inner part to be extended in the guide bush 7 to be manufactured by metal injection molding.

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1: outer part

2: protection

3: outer shell

4: end

5: donation

6: inner edge

7: guide bush

8: bore

9: first web

10: guide bore

11: radial side

12; Supply bore

13: first channel

14: first inlet

14a: second channel

15: second inlet

16: longitudinal groove

17: longitudinal groove

18: additional web

19: upper edge

20: upper edge

21: recess

22: recess

23: rug

24: rug

25: lower side

26: lower side

27: ring parts

28: outer edge

28: collar

Claims (11)

An outer part (1) of a switchable bucket tappet for a valve train of the engine, the outer part having a hollow cylindrical protective part (2) receivable within the guide bore of the cylinder head of the engine via the skin (3), The cam side end 4 of the protective part 2 is limited by the base 5 as the cam operating surface, and the guide bush 7 extending in a direction away from the cam from the inner edge 6 of the base 5 Formed concentrically with respect to the protection part 2 together with the bore 8 for the inner part of the bucket tappet, the protection part 2 extending radially through the outer part 1 at the bottom of the base; Connected with the guide bush 7 by a first web 9, a guide bore 10 for at least one sliding connection means is provided in the first web 9 and the first web 9. The radial side 11 of is the first sleeve starting from the first inlet in the shell 3 of the protective part 2. In the 13 supply bore outer portion of the switchable bucket tappet it is cut laterally by the 12 (1) for hydraulic medium to be supplied from, The outer part 1 is formed in one piece by a metal injection molding method (MIM) or precision casting, The base 5 is an outer part of the switchable bucket tappet, characterized in that it has a working surface of the cam which is convex in the cam direction. 2. The second channel (14a) integrally connected with the outer portion extends circumferentially offset with respect to the first channel (13) and the first web (9), and the second channel (14a) Switchable bucket, characterized in that the bore 8 of the guide bush 7 for cutting into the hydraulic clearance compensation element, starting from the second inlet 15 and arranged in the inner part, in the protection part 2 is cut off External part of the tappet. 3. The first and second inlets 14, 15 are positioned opposite one another on the diameter of the protective part 2, and the connecting lines of the first and second inlets 14, 15. The outer part of the switchable bucket tappet, characterized in that it intersects at least perpendicularly the first web (9) with a guide bore (10). delete 4. An additional web (18) according to claim 3 is formed, which is axially spaced with respect to the base (5) and extends in diameter through the outer part (1) and which is integrally connected with the outer part. Or one of each of the inlets 14, 15 extends radially outwardly in the peripheral region of the web, and the first channel 13 is inclined or obliquely from the first inlet 14 of the channel. A second channel 14a extending from the radial side 11 of the web 9 with the bore 10, starting from the second inlet 15, is arranged in the corresponding segment of the further web 18. An outer part of the switchable bucket tappet. The outer part 1 can be fixedly mounted in the guide bore of the outer part at the cylinder head such that the additional web 18 extends on the base 5 parallel to the cam movement direction. The base 5 has two upper edges 19, 20 in the form of bow demonstrations extending equidistantly to the longitudinal intermediate plane through the outer part 1, the upper edge running in a direction away from the cam. The outer part of the switchable bucket tappet, characterized in that it descends in the form of a roof on the additional web (18) to form two recesses (21, 22). 7. The bow-shaped upper edges 19, 20 of the recesses 21, 22 comprise a constant gap in the area of the diameter of the guide bush 7, or in the form of a secant of the guide bush. The outer part of the switchable bucket tappet, characterized by a slight crossing. 2. The shell 3 of the protective part 2 at the periphery where the inlets 14, 15 are arranged is above the base 5 by lugs 23, 24 which are integrally connected with the shell. An outer portion of the switchable bucket tappet, which extends. 6. The ring part 27 extends as a single end support for the lost motion spring in the lower portions 25, 26 of the webs 9, 18, wherein the ring part 27 is external to the ring part. An outer portion of the switchable bucket tappet, characterized in that it is optionally provided with a collar 29 projecting away from the edge 28 from the cam. delete 2. The outer part of the switchable bucket tappet according to claim 1, wherein a substantially constant wall thickness is provided on the outer part (1).

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