CN212202158U - Variable valve mechanism of internal combustion engine - Google Patents

Abstract

The utility model relates to a variable valve mechanism of an internal combustion engine, which comprises a camshaft (1); at least one switchable rocker arm (5), wherein the switchable rocker arm (5) provides a valve stroke for the corresponding valve in cooperation with the camshaft (1), and the switchable rocker arm (5) has a coupling element which can move along the axial direction; a sliding rod for actuating the coupling element in order to change the valve travel of the respective valve, wherein the sliding rod is arranged parallel to the camshaft (1) and is mounted on a cylinder head assembly of the internal combustion engine so as to be movable in the longitudinal direction, wherein a sliding element made of a polyamide material is provided in the sliding contact region of the sliding rod and the cylinder head assembly.

Description

Variable valve mechanism of internal combustion engine

Technical Field

The utility model relates to a variable valve mechanism of internal-combustion engine.

Background

By means of the variable valve mechanism, the intake and/or exhaust of the cylinders can be adjusted according to the driving mode of the vehicle, so that the fuel efficiency of the internal combustion engine is optimized, in particular in favor of reducing the emissions of carbon dioxide and harmful substances.

Different types of construction of variable valve trains are known from the prior art. In one embodiment, the internal combustion engine has at least one cylinder, on each of which at least one gas exchange valve is present, the valve travel of which is determined by a cam of a camshaft and a switchable rocker arm cooperating with the cam. Such a variable valve mechanism is disclosed in, for example, german patent document DE 202019101482U 1 and chinese patent document CN 110023594 a. In this type of variable valve mechanism, the switchable swing arm has a main arm and an auxiliary arm, wherein the auxiliary arm is pivotably supported on the main arm. By moving the coupling element in the axial direction of the camshaft, the coupling and decoupling of the main arm and the secondary arm can be achieved. In different coupled and decoupled states, the switchable rocker arm provides different valve strokes to the valve stem of the associated gas exchange valve, so that a variable valve stroke of the variable valve train is achieved. The axial actuation of the coupling element is effected by means of a slide rod which is actuated by an actuator, in particular an electric actuator. In this case, a slide bar is arranged on the cylinder head parallel to the camshaft and is slidable in the longitudinal direction relative to the cylinder head, on which slide bar a spring arm is provided which corresponds to the coupling element of the respective switchable rocker arm. When the sliding rod moves in the longitudinal direction thereof, each spring arm actuates the coupling element in the axial direction, so that switching between the coupling state and the decoupling state of the switchable rocker arm is realized, and the valve stroke is adjusted.

In the above solution, however, the slide rod is made of a steel or aluminum plate, while the cylinder head is made of aluminum. Sliding of the steel or aluminium slide rod directly on the aluminium cylinder head causes noise and friction problems, which are particularly serious in the case of deteriorated lubrication.

SUMMERY OF THE UTILITY MODEL

Therefore, the technical problem to be solved by the present invention is to provide a variable valve mechanism of an internal combustion engine, wherein the variable valve mechanism at least alleviates the noise problem caused by the movement of the sliding rod.

The object is achieved by a variable valve train of an internal combustion engine, comprising a camshaft, at least one switchable rocker arm and a sliding rod, wherein the switchable rocker arm provides a valve stroke for a respective valve in cooperation with the camshaft, and the switchable rocker arm has a coupling element which is movable in the axial direction; the sliding rod is used for actuating the coupling element in order to change the valve stroke of the corresponding valve, wherein the sliding rod is arranged parallel to the camshaft and is supported on a cylinder head assembly of the internal combustion engine in a longitudinally movable manner. According to the solution of the present invention, a sliding element made of polyamide material is provided in the sliding contact area of the sliding rod and the cylinder head assembly.

In the context of the present invention, unless otherwise specified, "axial" refers to the axial direction of the camshaft, and "longitudinal" refers to the longitudinal direction of the slide rod. The longitudinal direction of the slide rod is the axial direction of the camshaft. The switchable rocker arm can be designed according to prior art solutions. The coupling element can be designed according to the prior art as a coupling pin which moves in the axial direction. By cylinder head assembly is herein meant a cylinder head and a member fixed relative to the cylinder head. The slide bar is made of metal. In particular, the slide bar is made of aluminum or steel. In particular, the slide bar is made of sheet metal. The slide rod is driven by an adjuster, particularly an electric adjuster, to perform linear movement in a longitudinal direction relative to the cylinder head assembly. The adjuster is arranged, for example, on one axial end side of the camshaft. During the movement of the sliding rod in its longitudinal direction, the coupling element is actuated in the axial direction, for example by means of a spring arm arranged on the sliding rod, so that the coupling and decoupling between the main arm and the auxiliary arm of the switchable rocker arm is achieved, whereby different valve strokes are provided for the valve stem. The slide bar can thereby actuate the coupling elements of a plurality of switchable rocker arms simultaneously. The adjustment strategy of the slide bar for each rocker arm can be designed according to the prior art.

The sliding element is made of a polyamide material, for example PA66, PA 46. If desired, polyamide materials with glass fibers added can also be used, for example PA66 GF 30. By providing the sliding element composed of a polyamide material in the sliding contact area of the slide rod and the cylinder head assembly, direct contact between the slide rod and the slider can be avoided, thereby effectively reducing vibration noise. In addition, due to the good self-wetting and wear resistance properties of polyamide materials, wear of the parts due to movement of the slide bar can also be reduced.

In an advantageous embodiment, the cylinder head assembly comprises a cylinder head and a bearing cap arranged fixedly relative to the cylinder head, the sliding contact region being configured as a sliding channel formed by the cylinder head and the bearing cap together. The bearing cap is used, for example, to rotatably hold a camshaft. In this case, the slide groove, in which the slide rod can move longitudinally, extends parallel to the axial direction of the camshaft. The existing components can be utilized to realize the relatively sliding support of the sliding rod by the cylinder cover assembly without arranging an additional sliding rod support. In this case, the cylinder head can advantageously form the groove base of the sliding groove and the groove wall on the side close to the camshaft, and the bearing cap forms the groove wall on the side far from the camshaft, so that the existing cylinder head and/or bearing cap can be designed with little or no modification, and design effort and production costs can be saved. In addition, advantageously, a plurality of bearing caps distributed in the axial direction may be provided, so that stable support may be provided for both the camshaft and the slide rod.

The sliding element advantageously has a substantially U-shaped design, wherein the sliding element surrounds the sliding rod from its base upwards. That is, the slide member forms an accommodating groove opened upward, in which the slide bar is accommodated. Therefore, direct contact between the sliding rod and the cylinder cover assembly can be completely avoided, and noise and friction are effectively reduced. Advantageously, the substantially U-shaped structure is adapted to the shape of the sliding groove on the outside, and the groove shape of the receiving groove is adapted to the shape of the sliding rod, so that a stable support of the sliding rod by the cylinder head assembly is achieved, and a lateral sway of the sliding rod is effectively avoided. By "substantially U-shaped" is here understood that the sliding element may have a holding portion in addition to the U-shaped structure.

Depending on the holding position of the sliding element, a preferred embodiment is: the sliding element is fixed on the sliding rod. In this case, the slide member may slide with the slide bar along with the slide bar by its outer surface relative to the cylinder head assembly.

In this case, the base of the slide rod is preferably designed with a positioning structure which engages the slide element in the longitudinal direction. Advantageously, the locating formations may be projections corresponding to the longitudinal sides of the slide element. Alternatively, the locating structure may be a catch groove of the corresponding slide element. Alternatively, the locating feature may be in the form of a combination of the projections and the detents described above. The longitudinal positioning of the sliding element on the slide bar can thus be easily achieved.

Particularly preferably, the top of the two side walls of the sliding element is each formed with a catch projecting from the top in a direction perpendicular to the longitudinal direction. In this case, it is advantageous if the catch sections each cover the top of the slide rod at least in sections in the transverse direction, so that the slide element can be easily and stably fixed to the slide rod, which is particularly advantageous for assembly.

Particularly preferably, the upper parts of the two side walls of the sliding element are each formed with longitudinal projections extending in the longitudinal direction in opposite directions, on which the catch portions are each arranged. Thereby, when the sliding element moves along the longitudinal direction, the interference between the hook part and the cylinder cover component is effectively avoided. Furthermore, the provision of the longitudinal projection enables the sliding element to maintain as low a mass as possible while avoiding interference, which is advantageous in terms of both the function and the cost of the variable valve mechanism.

Another preferred embodiment, depending on the holding position of the sliding element, is: the sliding element is fixed to the cylinder head assembly. In this case, the slide rod may slide on the inner surface of the slide member relative to the slide member and the cylinder head assembly.

In this case, two latching arms are preferably formed underneath the sliding element, which latching arms are latched in the longitudinal direction on the cylinder head. Advantageously, the latching arm can be latched on a cylinder head structural part, in particular a projecting cylinder head structural part. Thereby preventing longitudinal movement of the slide member relative to the cylinder head assembly.

Particularly preferably, the ends of the two catch arms are each formed with a catch section which projects from the end in the longitudinal direction. The latching hook thus partially surrounds the lower contour of the cylinder head structural part, in particular of the cylinder head structural part, so that a simple and stable fastening of the sliding element on the cylinder head assembly is possible, which is particularly advantageous for assembly.

In summary, by providing the sliding element made of polyamide material in the sliding contact area of the slide rod and the cylinder head assembly, direct contact between the slide rod and the slider can be avoided, thereby effectively reducing vibration noise. In addition, due to the good self-wetting and wear resistance properties of polyamide materials, wear of the parts due to movement of the slide bar can also be reduced.

Drawings

Preferred embodiments of the present invention will be schematically described below with reference to the accompanying drawings. The attached drawings are as follows:

fig. 1 is a partial perspective view of a variable valve mechanism according to a first preferred embodiment;

FIG. 2 is an assembled perspective view of a slide bar and slide element according to a first preferred embodiment;

FIG. 3 is an enlarged partial view of area A of FIG. 2;

FIG. 4 is a front view of a slide bar according to a first preferred embodiment;

FIG. 5 is a perspective view of a sliding element according to a first preferred embodiment;

fig. 6 is a partial perspective view of a variable valve mechanism according to a second preferred embodiment;

fig. 7 is a partially enlarged perspective view of a variable valve mechanism according to a second preferred embodiment;

fig. 8 is a perspective view of a sliding element according to a second preferred embodiment.

In the above figures, identical or functionally identical components have been provided with the same reference numerals.

Detailed Description

Fig. 1 shows a partial perspective view of a variable valve mechanism according to a first preferred embodiment, showing a part of a cylinder head 2 of an internal combustion engine and a part of members arranged thereon. In the present embodiment, the internal combustion engine has four cylinders each having two gas exchange valves, i.e., an intake valve and an exhaust valve, respectively. The valve stems (not shown) of each gas exchange valve are each provided with a respective switchable rocker arm 5. On the cylinder head 2, a camshaft 1 is arranged, which camshaft 1 is rotatably held by the cylinder head 2 and four bearing caps 3 distributed approximately equidistantly. The bearing cap 3 is fixed to the cylinder head 2 by bolts 4. The cylinder head 2 and the bearing cap 3 are each made of a metal material, for example, aluminum. The camshaft 1 has cams corresponding to the switchable rocker arms 5, respectively. The switchable rocker arm 5 has a coupling element, for example a coupling pin, which can couple and decouple the main arm and the secondary arm by an axial movement.

In the present embodiment, a slide rod 71 made of an aluminum or steel plate material is slidably supported in a slide groove formed jointly by the cylinder head 2 and the bearing cap 3. The cylinder head 2 can form the groove base of the runner and the groove wall on the side close to the camshaft 1, and the bearing cap 3 can form the groove wall on the side far from the camshaft 1. In each sliding channel formed by the respective bearing cover 3 and the cylinder head 2, a sliding element 81 formed by a polyamide material is provided, respectively, the sliding rod 71 being arranged in the sliding element 81, the structure of the sliding element 81 being described in detail below. The slide rod 71 may be driven by an electric actuator (not shown) to perform linear movement in the longitudinal direction with respect to the cylinder head 2 and the bearing cap 3. A spring arm 6 is arranged on the slide bar 71, which spring arm can act on the coupling element of the respective switchable rocker arm 5. The coupling and decoupling of the main arm and the secondary arm can thus be achieved by the longitudinal movement of the individual switchable rocker arms 5 by means of the common sliding rod 71.

Fig. 2 shows an assembled perspective view of a slide bar 71 and a slide element 81 according to a first preferred embodiment, fig. 3 shows a partially enlarged view of the area a in fig. 2, and fig. 4 and 5 show a front view of the slide bar 71 and a perspective view of the slide element 81 according to the first preferred embodiment, respectively. The structure of the sliding element 81 according to the first preferred embodiment and the manner of fixing it can be clearly seen from figures 2 to 5.

As shown in particular in fig. 5, the sliding element 81 has a substantially U-shaped configuration which surrounds the sliding bar 71 from the bottom of the sliding bar 71 upwards. That is, the slide member 81 forms an accommodation groove 811 open upward, and the slide bar 71 is accommodated in the accommodation groove 811. Direct contact of the slide rod 71 with respect to the cylinder head 2 and the bearing cap 3 is thereby completely avoided, and noise and friction are effectively reduced. The sliding element 71 substantially matches the groove profile of the sliding channel formed by the respective bearing cap 3 and the cylinder head 2 on the outside, here with a substantially rectangular design. The slide bar 71 matches the shape of the slide bar 71 on the inside, i.e. the groove shape of the accommodation groove 811 matches the shape of the slide bar 71, here also substantially rectangular. Therefore, the stable support of the cylinder cover 2 and the bearing cover 3 assembly to the sliding rod 71 is realized, and the transverse shaking of the sliding rod 71 is effectively avoided.

As shown in fig. 2 and 3, in the present embodiment, a slide member 81 is fixed to the slide bar 71, and the slide member 81 slides with the slide bar 71 by its outer surface with respect to the cylinder head 2 and the bearing cap 3. As shown in fig. 4, the bottom of the slide bar 71 is configured with a positioning structure that catches the slide member 81 in the longitudinal direction. Here, the positioning structure is designed as bosses 711a, 711b extending downward from the bottom of the slide bar 71. The spacing of the protrusions 711a, 711b corresponds to the longitudinal dimension of the bottom of the sliding member 81, so that the sliding member 81 can be positioned in the longitudinal direction. The upper portions of both side walls of the slide element 81 are respectively configured with longitudinal projections 812 extending in opposite directions in the longitudinal direction. Hook portions 813 projecting from the top of the longitudinal projection portion 812 in a direction perpendicular to the longitudinal direction are provided on the longitudinal projection portions 812, respectively, and the hook portions 813 at least partially cover the top of the slide bar 71. This makes it possible to fix the sliding element 81 to the sliding rod 71 in a simple and stable manner, which is very advantageous in particular for assembly. At the same time, the longitudinal projections 812 also avoid interference of the hook 813 with respect to the head 2 and/or the bearing cap 3.

The variable valve mechanisms of the first preferred embodiment and the second preferred embodiment are basically identically configured. Only the differences between the two preferred embodiments, namely the structure of the sliding element and its manner of fixing, are described here.

Fig. 6 shows a partial perspective view of a variable valve mechanism according to a second preferred embodiment, fig. 7 shows a partial enlarged perspective view of the variable valve mechanism according to the second preferred embodiment, and fig. 8 shows a perspective view of a sliding member 82 according to the second preferred embodiment. The structure of the sliding element 82 and the manner of securing it according to the second preferred embodiment can be clearly seen from fig. 6 to 8.

As shown in fig. 6 and 7, in the present embodiment, the slide element 82 is fixed to a head structural member 201 of the head 2. In this case, the slide rod 72 may be designed according to existing slide rod solutions, with the slide rod 72 sliding on the inner surface of the slide member 82 relative to the slide member 82 and the cylinder head assembly.

As shown in fig. 8, the slide member 82 also has a substantially U-shaped configuration that surrounds the slide bar 72 from the bottom of the slide bar 72 upward. That is, the slide member 82 forms an upward-opening receiving groove 821 in which the slide rod 72 is received. The sliding element 82 is formed with two latching arms 822 below the receiving recess 821, the latching arms 822 being latched in the longitudinal direction on the cylinder head structural part 201 of the cylinder head 2. The ends of the two latching arms 822 are each formed with a latching hook 823 which projects from the respective end in the longitudinal direction, the latching hooks 823 partially enclosing the underside contour of the cylinder head structural part 821, so that the sliding element 82 can be easily and stably fixed on the cylinder head 2, which is particularly advantageous for assembly.

Although possible embodiments have been described by way of example in the above description, it should be understood that numerous embodiment variations exist, still by way of combination of all technical features and embodiments that are known and that are obvious to a person skilled in the art. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. From the foregoing description, one of ordinary skill in the art will more particularly provide a technical guide to convert at least one exemplary embodiment, wherein various changes may be made, particularly in matters of function and structure of the components described, without departing from the scope of the following claims.

List of reference numerals

1 camshaft

2 Cylinder cover

201 Cylinder cover structure

3 bearing cap

4 bolt

5 switchable rocker arm

6 spring arm

71 sliding rod

711a boss

711b bulge

81 sliding element

811 accommodating groove

812 longitudinal projection

813 hook part

72 sliding rod

82 sliding element

821 holding groove

822 clip arm

823 hook part

Claims (10)

1. A variable valve mechanism of an internal combustion engine, the variable valve mechanism comprising:

-a camshaft (1);

-at least one switchable rocker arm (5), which switchable rocker arm (5) provides a valve stroke for a respective valve in cooperation with the camshaft (1), and which switchable rocker arm (5) has a coupling element that is movable in the axial direction;

-a sliding rod for actuating the coupling element for changing the valve stroke of the respective valve, wherein the sliding rod is arranged parallel to the camshaft (1) and is mounted on a head assembly of the internal combustion engine so as to be movable in the longitudinal direction,

characterized in that a sliding element made of a polyamide material is provided in the sliding contact area of the slide rod and the cylinder head assembly.

2. Variable valve mechanism according to claim 1, characterized in that the cylinder head assembly comprises a cylinder head (2) and a bearing cap (3) arranged fixedly relative to the cylinder head (2), the sliding contact area being configured as a sliding channel jointly constituted by the cylinder head (2) and the bearing cap (3).

3. The variable valve mechanism according to claim 2, characterized in that the slide member has a substantially U-shaped structure in which the slide member surrounds the slide bar upward from the bottom thereof.

4. Variable valve mechanism according to claim 3, characterized in that the sliding element is fixed on the sliding rod.

5. The variable valve mechanism according to claim 4, wherein a bottom portion of the slide rod is configured with a positioning structure that catches the slide element in a longitudinal direction.

6. The variable valve mechanism according to claim 5, wherein top portions of both side walls of the slide member are respectively configured with a hook portion projecting from the top portions in a direction perpendicular to the longitudinal direction.

7. Variable valve mechanism according to claim 6, characterized in that the upper parts of the two side walls of the sliding element are each configured with a longitudinal projection (812) extending in the longitudinal direction in opposite directions, the catch portions being provided on the longitudinal projections (812), respectively.

8. The variable valve mechanism according to claim 3, wherein the sliding member is fixed to the head assembly.

9. Variable valve mechanism according to claim 8, characterized in that two latching arms (822) are configured below the sliding element, the latching arms (822) being latched in the longitudinal direction on the cylinder head (2).

10. Variable valve mechanism according to claim 9, characterized in that the ends of the two catch arms (822) are each configured with a catch portion projecting longitudinally from said end.

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