Abstract
A valve rotating device with valve stem seal includes a valve rotating device, with a cylinder head rest and a spring rest intended to bear against a valve spring during operation. The valve rotating device is designed to rotate the spring rest relative to the cylinder head rest during operation. A valve stem seal is attached to the cylinder head rest of the valve rotating device. The valve stem seal being designed to bear against a valve stem and to seal same during rotational and axial movements.
Claims
1. A valve rotating assembly for a gas-exchange valve of an internal combustion engine, the valve rotating assembly comprising: a valve rotating device configured to bear against at least one valve spring during operation of the valve, the valve rotating device including a cylinder head rest, a spring rest, and a valve stem seal; wherein the spring rest is configured to rotate relative to the cylinder head rest during the operation of the valve; and wherein the valve stem seal is attached to the cylinder head rest so as to bear against a valve stem of the valve, the valve stem seal configured to seal the valve stem during rotational and axial movements of the valve stem.
2. The valve rotating assembly according to claim 1, further comprising a cylinder head rest seal configured to seal the cylinder head rest against a face of a cylinder head of the engine.
3. The valve rotating assembly according to claim 1, further comprising a valve stem guide axial seal configured to seal the cylinder head rest against an axial end face of a valve stem guide of the engine.
4. The valve rotating assembly according to claim 1, further comprising a valve stem guide radial seal configured to seal the cylinder head rest against a lateral face of a valve stem guide of the engine.
5. The valve rotating assembly according to claim 1, further comprising a cylinder head rest outer seal configured to seal the cylinder head rest against a radial surface of a cylinder head of the engine.
6. The valve rotating assembly according to claim 1, wherein the valve stem seal includes at least one seal spring that presses the valve stem seal radially inwards against the valve stem.
7. The valve rotating assembly according to claim 1, wherein the valve rotating device further includes a disc spring, rolling elements, and springs.
8. The valve rotating assembly according to claim 7, wherein the valve rotating device further includes at least one rolling or sliding bearing.
9. The valve rotating assembly according to claim 1, wherein the spring rest includes an anti-rotation support configured to prevent a rotation of the at least one valve spring relative to the spring rest.
10. A valve rotating assembly for a gas-exchange valve of an internal combustion engine, the valve rotating assembly comprising: a valve rotating device configured to bear against a valve spring during operation of the valve, the valve rotating device including a cylinder head rest, a spring rest, and a valve stem seal; wherein the spring rest is configured to rotate relative to the cylinder head rest during the operation of the valve; and wherein the valve stem seal is attached to the spring rest so as to bear against a valve stem of the valve, the valve stem seal configured to seal the valve stem during rotational and axial movements of the valve stem.
11. The valve rotating assembly according to claim 10, further comprising a spring rest valve stem guide seal configured to seal the spring rest against a lateral face of a valve stem guide of the engine.
12. A valve rotating assembly for a gas-exchange valve of an internal combustion engine, the valve rotating assembly comprising: a valve rotating device configured to be fastened to a valve stem end of the valve, the valve rotating device including a spring disc, a valve stem fastening, and a valve stem seal; wherein the valve stem fastening is configured to rotate relative to the spring disc during operation of the valve; and wherein the valve stem seal is attached to the valve stem fastening so as to bear against a valve stem of the valve, the valve stem seal configured to seal the valve stem during rotational and axial movements of the valve stem.
13. The valve rotating assembly according to claim 12, further comprising a valve stem guide seal configured to seal the valve stem fastening against a lateral face of a valve stem guide of the engine.
14. A valve rotating assembly for a gas-exchange valve of an internal combustion engine, the valve rotating assembly comprising: a valve rotating device configured to be fastened to a valve stem end of the valve, the valve rotating device including a spring disc, a valve stem fastening, and a valve stem seal; wherein the valve stem fastening is configured to rotate relative to the spring disc during operation of the valve; and wherein the valve stem seal is attached to the spring disc so as to bear against a valve stem of the valve, the valve stem seal configured to seal the valve stem during rotational and axial movements of the valve stem.
15. The valve rotating assembly according to claim 14, further comprising a valve stem guide seal attached to the spring disc so as to seal the spring disc against a lateral face of a valve stem guide of the engine.
Description
THE DRAWINGS
(1) The present invention is illustrated below using schematic diagrams, which are not to scale, of different exemplary embodiments.
(2) FIGS. 1A to 1E show different embodiments of the valve rotating device according to the invention having a valve stem seal, in which a part of a valve rotating device resting directly on a cylinder head provides the sealing.
(3) FIGS. 2A to 2C show valve rotating devices according to the invention with valve stem seals, in which a part of a valve rotating device directly connected to a valve spring provides the sealing.
(4) FIGS. 3 and 4 show valve rotating devices according to the invention having valve stem seals, in which the sealing is provided at the top on the valve stem end of a valve.
DETAILED DESCRIPTION
(5) In the FIGURES, only the sectional plane itself is shown for all elements with the exception of the sloping planes and the valve spring, as a result of which a clearer view of the rotationally symmetrical components is achieved.
(6) The same or similar reference signs are used both in the FIGURES and in the description to refer to the same or similar components or elements. Therefore, to keep the description concise, not all the elements in all the FIGURES are described individually if their function has already been described in a previous figure.
(7) FIG. 1A shows a partial sectional view through a cylinder head 52, at the point at which a valve stem 56 emerges from the top of the cylinder head. Between the cylinder head 52 and the valve stem 56 there is a valve stem guide, which can also be omitted, in particular in the embodiments of FIGS. 1A to 1D. Resting directly on the cylinder head 52 there is a valve rotating device with valve stem seal 2, on which a valve spring 12 is supported, which is connected to the valve stem end at the other end (not shown). The valve rotating device 6 is formed in the lower part of the valve rotating device with valve stem seal 2, and the valve stem seal 4 is molded on in the upper part. The valve rotating device 6 rests with the cylinder head rest 8 on the cylinder head 52. Sloping planes 42 are provided in the cylinder head rest 8, via which sloping planes rolling elements 40, shown here as balls, can roll. The rolling elements 40 are each pressed against the upper end of the sloping planes 42 by means of restoring springs (not shown). Above the cylinder head rest 8 there is a spring rest 10 on which the valve spring 12 rests. A disc spring 44 is also arranged between the cylinder head rest 8 and the spring rest 10 and keeps these two elements at a distance from one another. When the valve is actuated or opened, the valve spring 12 is first compressed until the force becomes great enough to compress the disc spring 44. When the disc spring 44 deforms, it lifts off from the cylinder head rest 8 on the inside and can roll over the sloping planes 42 via the rolling elements 40 counter to the force of the restoring springs. Here, this causes an anti-clockwise rotation of the valve spring 12, which is transmitted via the upper end of the valve spring 12 to the valve stem 56. This rotation can prevent a situation in which damage can have a greater effect at one point on the valve seat or on the valve disc.
(8) In FIG. 1A, the cylinder head rest 8 rests fixedly on the cylinder head and is prevented from rotating by the force of the valve spring 12 thereon. The cylinder head rest 8 is further provided with a collar or a protrusion with which the cylinder head rest 8 and thus the entire valve rotating device 6 can be centred relative to the valve stem guide 54. A valve stem seal 4 of the cylinder head rest 8 is injection-molded to the top of the collar on the cylinder head rest 8 or the protrusion thereof. In FIG. 1A, the valve stem seal of the cylinder head rest or cylinder head rest valve stem seal 4 is reinforced by a seal spring 46, which makes it possible to achieve a uniform pressing pressure of the cylinder head rest valve stem seal 4 even at different operating temperatures. In the embodiment shown, a separate valve stem seal can then be omitted, since it was possible to combine these two elements in a more complex component. The cylinder head rest 8 is sealed off by a combination of the pressing pressure of the valve spring and a lubricant present in the cylinder head without the need for a separate seal. The integration of two components means that the number of parts needed, the costs for two different parts, and most of all the number of assembly processes during assembly of an internal combustion engine can be considerably reduced. It should primarily be noted that the valve stem guide 54 can also be made simpler, since an interface for mounting and holding a conventional valve stem seal no longer has to be provided. This can allow the wall thickness of the valve stem guide to be reduced in comparison with the conventional design. The present invention therefore not only creates the possibility of combining two components in one but also permits the entire cylinder head design to be revolutionized, if that is possible after over 100 years of development.
(9) FIG. 1B shows an embodiment of the valve rotating device with valve stem seal 2 similar to that of FIG. 1A, wherein a valve stem guide seal or valve stem guide axial seal 16 is additionally provided and is supported at the top in the axial direction on the end face of the valve stem guide 54. By means of this embodiment, it is possible to keep a space between the cylinder head rest valve stem seal 4 and the valve stem guide axial seal 16 very small. Here, a counterpressure, which can effectively prevent further flow of fluids, can build up very rapidly, even if there is a slight leak between the valve stem guide 54 and the valve stem 56. In FIG. 1B, the valve stem guide 54 and the protrusion of the cylinder head rest 8 are larger or longer, which can result in advantages when guiding the valve stem 56. The function of the valve rotating device 6 corresponds to that of FIG. 1A.
(10) In FIG. 1C, the cylinder head rest 8 opposite the cylinder head 52 is provided with a cylinder head rest seal 14 in the form of a flat seal. Owing to the low tolerances and the low roughness on the cylinder head, the cylinder head rest seal 14 can be designed as a flat seal or else formed by a sealing coating or a thin elastomer layer. This embodiment corresponds substantially to FIG. 1A. Owing to the small thickness of the flat seal, relatively low requirements are made of the material of the cylinder head rest seal 14.
(11) In FIG. 1D, the cylinder head rest 8 is provided on an outer side with a circumferential groove, in which an O-ring is laid as the cylinder head rest outer seal 20. O-rings are particularly suitable as a static seal when laid in an annular groove. After the O-ring is laid in the groove, its shape prevents it from being able to fall out of the groove. Thanks to the O-ring, the cylinder head rest 8 and thus the entire valve rotating device 6 can be centred in the cylinder head. Owing to the large diameter, it is also possible here for very low requirements to be made of the strength, since a corresponding load is distributed to the entire circumference and thus to a large area.
(12) FIG. 1E largely corresponds to the embodiment of FIG. 1A, wherein the cylinder head rest seal is designed as a combination seal and is likewise used as a valve stem guide seal or valve stem guide radial seal 18. Here, the valve spring permits a radial seal by compression of the seal 14/18 in the axial direction by means of the valve spring 12.
(13) In all embodiments of FIGS. 1B to 1E, the cylinder head rest seal 14 is designed as a static seal, which allows cost-effective manufacturing. In FIG. 1B, the valve stem seal 4 of the cylinder head rest 8 and the valve stem guide axial seal 16 are formed integrally, which is likewise possible in FIG. 1E with or without changing the embodiment. It is also envisioned to provide a combination of FIGS. 1B and 1E, wherein multiple seals are attached to the cylinder head rest. Multiple sealing lips can also be provided, and the entire design can differ from that shown.
(14) FIGS. 2A to 2C show a further embodiment in which the valve stem seal is not attached to the cylinder head rest but to the spring rest 10.
(15) In FIG. 2A, the spring rest 10 is provided with a tubular protrusion, which lies around the valve stem guide 54 and protrudes upwards in the direction of the valve stem end, beyond same. A valve stem seal 22 of the spring rest 10 or spring rest valve stem seal 22 is cast on the protrusion of the spring rest 10. This seal can be provided with a seal spring 46, as shown. This embodiment differs in the fastening point of the valve stem seal 22. The valve stem seal 22 rotates with the valve spring 12 and the valve stem 56, as a result of which it becomes possible to design the seal as a simple seal for axial displacements. This makes it possible to use a sealing lip or a seal that can provide a translational sealing function but not a rotational sealing function. In the basic form, the gap between the spring rest 10 and the cylinder head rest 8 is achieved by the disc spring 44 and by the force with which the valve spring presses the cylinder head rest 8 against the cylinder head 52.
(16) In FIG. 2A, another flat seal is provided between the cylinder head rest 8 and the cylinder head 52.
(17) FIG. 2B shows a further embodiment in which, in contrast to the embodiment of FIG. 2A, a valve stem guide seal 24 of the spring rest 10 or a spring rest valve stem guide seal 24 is provided. The spring rest valve stem seal 22 can in this case be designed as a simple translational seal. However, the spring rest valve stem guide seal 24 must be able to seal both translationally and rotationally, wherein the translational movement is much smaller than the rotational one.
(18) FIG. 2C is intended to illustrate the movement of the valve rotating device. The outlines of FIG. 2B are shown with dashed lines. The rolling elements 40 have rolled down the sloping planes of the cylinder head rest 8 and have shifted the spring rest 10 downwards and in the clockwise direction as viewed from above.
(19) FIG. 3 shows an embodiment in which the valve rotating device 6 is arranged at the top between the valve stem end and the valve spring. The embodiment corresponds substantially to that of FIGS. 1A to 1E, wherein the protrusion is much longer and is sealed off both against the valve stem 56 and against the valve stem guide. Depending on the dimensions of the valve stem guide, this can also be advantageous in comparison with the embodiment with the valve rotating device at the bottom. In this case, the valve spring rest is formed by the valve spring disc, and the valve fastening corresponds to the cylinder head rest.
(20) In FIG. 3, the valve fastening 28 rotates with the valve stem, for which reason a static seal can be used here for sealing between the valve fastening 28 and the valve stem 56. This embodiment is suitable in particular for engines having long valve stem guides that protrude a long way.
(21) FIG. 4 corresponds substantially to the embodiment of FIG. 3 with the difference that on the one hand the seals are attached to the valve spring disc 26 and on the other hand there is no seal between the valve stem 56 and the valve fastening 28. This embodiment is also suitable in particular for engines having long valve stem guides that protrude a long way. In FIG. 4, the spring disc 26 is provided with an anti-rotation means 48 for the valve spring 12, and the rest face of the valve spring 12 on the cylinder head 52 is likewise provided with an anti-rotation means 50 for the valve spring 12, as a result of which a form-fitting connection is achieved between the valve disc and the cylinder head, via which the force generated by the rotating device 6 can be supported on the engine block.
(22) The invention can be practiced otherwise than described in the above embodiments which are specific examples which are descriptive rather than limiting in nature. The invention is defined in the appended claims.
