阅读说明：本技术 用于内燃机的气门传动装置 (Valve gear for internal combustion engine ) 是由 G·埃默斯伯格 D·克诺尔 R·克拉夫特 R·施密德 T·施泰因勒 于 2018-07-12 设计创作，主要内容包括：用于内燃机的气门传动装置,该气门传动装置包括可转动地支承在第一和第二凸轮轴轴承中的具有至少一个凸轮的第一凸轮轴,所述凸轮具有第一凸轮曲线和与第一凸轮曲线不同的第二凸轮曲线,利用第一或第二凸轮曲线能操纵换气阀,设有凸轮轴区段,凸轮能利用该凸轮轴区段经由调节器件来移动,使得换气阀能经由第一或第二凸轮曲线来操纵,第一凸轮轴和凸轮相对彼此具有固定的位置,并且第一凸轮轴能在第一和第二凸轮轴轴承中轴向移动。通过该气门传动装置的按照本发明的设计方案能实现相对于现有技术制造成本明显减少,并且避免了不期望的齿部噪音。(A valve drive for an internal combustion engine, comprising a first camshaft, which is mounted rotatably in a first and a second camshaft bearing and has at least one cam, which has a first cam curve and a second cam curve, which is different from the first cam curve, with which gas exchange valves can be actuated, a camshaft section is provided, with which the cam can be moved via an adjusting means, such that the gas exchange valves can be actuated via the first or the second cam curve, the first camshaft and the cam having a fixed position relative to one another, and the first camshaft being axially movable in the first and the second camshaft bearing. The design according to the invention of the valve drive makes it possible to achieve a significant reduction in production costs compared to the prior art and to avoid undesirable tooth system noise.)

1. Valve drive (1) for a cylinder head (16) of an internal combustion engine, comprising a first camshaft (4) which is rotatably mounted in a first camshaft bearing (2) and a second camshaft bearing (3) and which comprises at least one cam (5) having a first cam curve (6) and a second cam curve (7) which is different from the first cam curve (6), wherein gas exchange valves can be actuated by means of the first or second cam curves (6, 7), wherein a camshaft section (8) is provided with which the cam (5) can be moved by means of an adjusting means (9) such that the gas exchange valves can be actuated by means of the first or second cam curves (6, 7), characterized in that the first camshaft (4) and the cam (5) have a fixed position relative to one another, and the first camshaft (4) is axially displaceable in the first and second camshaft bearings (2, 3).

2. A valve gear according to claim 1, characterized in that the cam (5) and the camshaft (4) are one-piece and of identical material.

3. A valve gear according to claim 1, characterized in that the cam (5) is engaged or retracted onto the camshaft (4).

4. A valve gear according to one of claims 1 to 3, characterized in that the camshaft (4) is hollow.

5. A valve gear according to one of claims 1 to 4, wherein the valve gear (1) has a second camshaft (12) rotatably mounted in third and fourth camshaft bearings (10, 11) and arranged parallel to the first camshaft (4), characterized in that a first spur gear (13) is arranged radially around the first camshaft (4) and a second spur gear (14) is arranged radially around the second camshaft (12), wherein the first spur gear (13) and the second spur gear (14) are in operative connection with one another via a third spur gear (15).

6. A valve gear according to one of claims 1 to 5, characterised in that the first camshaft (4) has a plurality of cams (5) with two cam curves and is provided for at least two cylinders of an internal combustion engine arranged in a row.

Technical Field

The invention relates to a valve drive for an internal combustion engine having the features of the preamble of claim 1.

Background

For the technical environment reference is made, for example, to european patent application EP0595060a 1. From this patent application, a valve drive of an internal combustion engine is known, which has a preloaded sliding cam that can be displaced axially on a camshaft. The sliding cam is movable in a first position in which it interacts with a first convex curve on the intake valve to a second position in which it interacts with a second convex curve on the intake valve. In the first position, the sliding cam bears positively against a stop of a transmission element connected between the intake valve and the sliding cam, provided that the sliding cam runs in a section in the region of the stop. Upon reaching the base circle of the glide cam, the glide cam is moved into the second position.

Another example for a sliding cam is known, for example, from german laid-open patent application DE102005006489a 1. To a camshaft assembly having a base shaft and an axially movable but rotationally fixed cam carrier disposed on the base shaft. Cams having a plurality of cam curves are formed on the cam carrier, each cam having a common base circle and different cam curves, the cam curves having different curve profiles from one another. The valve operating device of the associated cylinder is operated by a cam. An actuator is provided for carrying out a switching process, wherein, by an axial displacement of the cam carrier on the base shaft during the switching process, a further cam curve of the cam curves comes into contact with the valve actuating element.

A further valve drive for an internal combustion engine is known from german laid-open patent application DE102004022833a 1. The valve drive comprises a camshaft with a sliding cam mechanism having cam tracks which are arranged next to one another and act on the valves and have different cam shapes and travel curves which cooperate with an actuating element having a control pin for adjusting the moving cam mechanism.

Known switching cams or sliding cams for multi-cylinder internal combustion engines have an externally toothed drive shaft on which an internally toothed sliding part is axially displaced. The manufacture of the toothing is expensive and subject to tolerances, which, in addition to economic disadvantages, also brings about acoustic disadvantages.

Disclosure of Invention

The object of the invention is to avoid the disadvantages mentioned above.

This object is achieved by the features in the characterizing part of claim 1.

Advantageous embodiments of the invention are specified in the dependent claims.

The embodiment according to the invention achieves a significant reduction in production costs, since no precise toothing needs to be produced. Undesirable tooth noise is also avoided.

The embodiments according to claims 2 and 3 represent two particularly preferred embodiments.

The design according to claim 4 significantly reduces the mass moved during the switching process, so that a significantly faster switching process can be achieved.

The design according to claim 5 allows the intake-side valve drive and the exhaust-side valve drive to be actuated.

With the design according to claim 6, it is possible to form an internal combustion engine with a plurality of cylinders and a movable camshaft. In this case, it can be, for example, an inline two-cylinder internal combustion engine, an inline three-cylinder internal combustion engine or an inline four-cylinder internal combustion engine, or also a V4 internal combustion engine or a V6 internal combustion engine.

Drawings

The invention is explained in detail below with the aid of a single figure according to one exemplary embodiment.

Fig. 1 shows a plan view of a valve drive according to the invention for an internal combustion engine.

Detailed Description

Fig. 1 shows a top view of a valve drive 1 according to the invention for a cylinder head 16 of an internal combustion engine, not shown in detail.

The cylinder head 16 is shown without a valve cover, so that a free view is available to the valve drive 1. The cylinder head 16 is provided for a four-cylinder internal combustion engine and has an intake side with two first valve transmissions 1 according to the invention, of which only one is marked with a reference numeral. On the exhaust side, the cylinder head 16 has a single second exhaust camshaft 12 for all four cylinders. On the intake side, a valve drive 1 according to the invention is provided for each of the two cylinders. Only one intake-side valve drive is indicated. The first camshaft 4 is mounted rotatably in a first camshaft bearing 2 and a second camshaft bearing 3, wherein only bearing blocks with thread connection bores, not shown, are shown in the cylinder head 16.

The first camshaft 4 has four cams 5, of which only one cam 5 is designated. The cam 5 has a first cam curve 6 and a second cam curve 7 different from the first cam curve 6. The gas exchange valves (not shown) can be actuated via an intermediate element (not shown), for example a sliding drag lever, by the first cam curve 6 or the second cam curve 7.

Furthermore, a camshaft section 8 is provided, which has a radially encircling control groove, not shown, with which the first camshaft 4 can be moved axially in the camshaft bearings 2, 3 via an adjusting means 9 by means of a pin which projects into the control groove. The first camshaft 4 can be displaced in such a way that the cams 5 actuate the gas exchange valves via intermediate elements either via the first cam curve 6 or via the second cam curve 7. Since the adjusting means 9 are known from the prior art, they are not explained in detail.

According to the invention, the first camshaft 4 and the cam 5 have a fixed position relative to one another, wherein the entire camshaft 4 can be moved axially in the first camshaft bearing 2 and the second camshaft bearing 3.

In the first embodiment, the cam 5 and the camshaft 4 are made in one piece and of uniform material, for example by casting together with subsequent post-processing. In another embodiment, the cam 5 may also be engaged or retracted onto the first camshaft 4. Can also be produced by an internal high pressure forming method (IHU).

In a particularly preferred embodiment, the camshaft 4 is hollow in order to reduce the moving mass, which enables a switching process that is switched significantly faster with the adjusting means 9.

The entire camshaft 4 is thus displaced axially in relation to the known prior art, so that the two different cam curves 6, 7 of the cam 5 are alternately in operative connection with the gas exchange valves. It is also possible to form more than two cam curves 6, 7.

The embodiment according to the invention thus achieves a significant reduction in production costs, since no precise axial toothing needs to be produced. Undesirable tooth noise is also advantageously completely avoided, which leads to a significant improvement in the acoustic performance. The valve drive 1 according to the invention is therefore suitable not only for single-track vehicles, such as mopeds and motorcycles, but also for all types of motor vehicles.

Furthermore, as already indicated, the valve drive 1 has, on the exhaust gas side, a second camshaft 12 which is rotatably mounted in parallel to the first camshaft 4 in a third camshaft bearing 10 and a fourth camshaft bearing 11 and two further camshaft bearings which are not indicated. On the end side, the first camshaft 4 has a first spur gear 13 extending radially around the camshaft 4, and the second camshaft 12 has a second spur gear 14 extending radially around the second camshaft 12, wherein the first spur gear 13 and the second spur gear 14 are in operative connection with one another via a third spur gear 15. The same gear mechanism is located in mirror image on the other end of the second camshaft 12 for driving the second, not illustrated, intake-side first camshaft. Therefore, the phase-locked drive can be realized not only on the intake side but also on the exhaust side.

Thus, according to the invention, the sliding camshaft is formed instead of the sliding cam. The embodiment according to the invention achieves a significant reduction in production costs, since no precise toothing needs to be produced. Undesirable tooth noise is also avoided.

List of reference numerals

1 valve gear

2 first camshaft bearing

3 second camshaft bearing

4 first camshaft

5 cam

6 first cam curve

7 second cam curve

8 camshaft section

9 adjusting device

10 third camshaft bearing

11 fourth camshaft bearing

12 second camshaft

13 first spur gear

14 second spur gear

15 third spur gear

16 cylinder head