Valve drive for an internal combustion engine

Abstract

A valve drive for an internal combustion engine may include a cam shaft, at least one cam follower, and at least one adjusting device. The at least one adjusting device may include a first adjustable engagement element and a second adjustable engagement element. The first engagement element may not contact a first guide in an initial position, and may cooperate with the first guide in a switching position. The second engagement element may not contact a second guide of a slide guide in an initial position, and may cooperate with the second guide in a switching position. The at least one adjusting device may further include a switching arrangement that may include a first control element mounted to the first engagement element and a second control element mounted to the second engagement element. The first control element and the second control element may be controllable via the switching arrangement.

Claims

1. A valve drive for an internal combustion engine, the valve drive comprising: a cam shaft and at least one cam follower; the cam shaft including at least one cam group mounted to the cam shaft in a rotationally fixed manner, the at least one cam group including a first cam and a second cam disposed axially adjacent to the first cam; the at least one cam follower being drivingly connected to the first cam when in a first position and drivingly connected to the second cam when in a second position; at least one adjusting device including a first adjustable engagement element and a second adjustable engagement element arranged next to one another at a distance on the at least one cam follower; the first engagement element comprising a pin cooperating with a first guide of a slide guide arranged on the cam shaft, and the second engagement element comprising a pin cooperating with a second guide of the slide guide; wherein the first engagement element and the second engagement element alternately adjust between an initial position and a switching position; wherein the first engagement element does not contact the first guide when in the initial position, and the first engagement element cooperates with the first guide when in the switching position; wherein the second engagement element does not contact the second guide when in the initial position, and the second engagement element cooperates with the second guide when in the switching position; wherein the at least one adjusting device further includes a switching arrangement including a first control element mounted to the first engagement element and a second control element mounted to the second engagement element, the first control element and the second control element each including a radially outwardly extending portion that interacts with a first stop area and a second stop area of the switching arrangement, respectively, wherein the first control element and the first engagement element are controlled via the first stop area of the switching arrangement, and the second control element and the second engagement element are controlled via the second stop area of the switching arrangement such that the first engagement element and the second engagement element adjust from the initial position to the switching position; and wherein the at least one cam follower includes at least one guide recess, in which at least one of the first control element and the second control element is arranged and guided parallel to a longitudinal axis of a corresponding one of the first engagement element and the second engagement element.

2. The valve drive according to claim 1, wherein the at least one adjusting device includes a fastener and a counter fastener structured and arranged complementary to the fastener, and wherein at least one of the first control element and the second control element are mounted to a respective one of the first engagement element and the second engagement element via the fastener and the counter fastener.

3. The valve drive according to claim 2, wherein: the fastener is a through groove extending one of parallel and perpendicular to the longitudinal axis of the respective one of the first engagement element and the second engagement element; and the counter fastener is a formation disposed complementary and integral to the through groove, the counter fastener disposed on the at least one of the first control element and the second control element.

4. The valve drive according to claim 2, wherein one of: the fastener is arranged on the at least one of the first control element and the second control element, and the counter fastener is arranged on e respective one of the first engagement element and the second engagement element; and the counter fastener is arranged on the at least one of the first control element and the second control element, and the fastener is arranged on the respective one of the first engagement element and the second engagement element.

5. The valve drive according to claim 2, wherein the fastener and the counter fastener are structured and arranged to provide a screw connection.

6. The valve drive according to claim 1, wherein at least one of the first control element and the second control element is one of s-shaped and c-shaped.

7. The valve drive according to claim 1, wherein the slide guide includes at least one resetting arrangement configured to adjust at least one of the first engagement element and the second engagement element into the initial position.

8. The valve drive according to claim 1, wherein the switching arrangement is structured and arranged to pivot about an angle to control the first control element through the first stop area and to control the second control element through the second stop area in an alternating manner.

9. The valve drive according to claim 1, wherein the switching arrangement is structured and arranged to shift along a longitudinal axis of the at least one cam follower to control the first control element and the second control element via a displacement through the first stop area and through the second stop area, respectively, in an alternating manner.

10. The valve drive according to claim 1, wherein the switching arrangement is activated via an actuator such that at least one of the first control element and the second control element is controlled via activation of the switching arrangement.

11. The valve drive according to claim 10, wherein the actuator is one of a hydraulic actuator, an electromagnetic actuator, and a pneumatic actuator.

12. The valve drive according to claim 1, wherein the switching arrangement is mounted to a cylinder head.

13. The valve drive according to claim 1, wherein the at least one guide recess includes a first guide recess structured and arranged to guide the first control element and a second guide recess structured and arranged to guide the second control element.

14. The valve drive according to claim 1, further comprising a rocker arm rotatably mounted on a rocker arm shaft, and wherein the at least one cam follower is operatively connected to the rocker arm.

15. The valve drive according to claim 1, wherein the switching arrangement is arranged radially between the cam shaft and the at least one cam follower relative to a rotation axis of the cam shaft.

16. A valve drive for an internal combustion engine, the valve drive comprising: a cam shaft including at least one cam group rotationally arranged on the cam shaft, the at least one cam group including a first cam and a second cam disposed axially adjacent the first cam; at least one cam follower being drivingly connected to the first cam when in a first position and drivingly connected to the second cam when in a second position; and at least one adjusting device including a first engagement element and a second engagement element arranged on the at least one cam follower at a distance from one another, the first engagement element comprising a pin interacting with a first guide of a slide guide arranged on the cam shaft when in a switching position and not contacting the first guide when in an initial position, the second engagement element comprising a pin interacting with a second guide of the slide guide when in the switching position and not contacting the second guide when in the initial position; the at least one adjusting device further including a switching arrangement including a first control element mounted to the first engagement element and a second control element mounted to the second engagement element, the first control element and the second control element each including a radially outwardly extending portion that interacts with a first stop area and a second stop area of the switching arrangement, respectively; wherein the first engagement element and the first control element are adjusted from the initial position to the switching position via the first stop area, and the second engagement element and the second control element are adjusted from the initial position to the switching position via the second stop area; and wherein the switching arrangement is structured and arranged to pivot about an angle such that the first control element is adjusted via the first stop area and the second control element is adjusted via the second stop area.

17. The valve drive according to claim 16, wherein the first control element is mounted to the first engagement element and the second control element is mounted to the second engagement element, respectively, via a fastener and a counter fastener disposed complimentary to the fastener.

18. The valve drive according to claim 17, wherein the fastener is a through groove extending parallel to a longitudinal axis of a respective one of the first engagement element and the second engagement element, and the counter fastener is a formation structured and arranged to engage with the through groove, wherein the formation is disposed complementary to the through groove on a respective one of the first control element and the second control element.

19. The valve drive according to claim 17, wherein the fastener is a through groove extending perpendicular to a longitudinal axis of a respective one of the first engagement element and the second engagement element, and the counter fastener is a formation structured and arranged to engage with the through groove, wherein the formation is disposed complementary to the through groove on a respective one of the first control element and the second control element.

20. The valve drive according to claim 19, wherein the first control element and the second control element are mounted at a longitudinal end of the first engagement element and the second engagement element, respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In each case schematically,

(2) FIG. 1 shows a view of a valve drive according to the invention;

(3) FIG. 2 shows a view of a valve drive according to the invention comprising a switching arrangement, wherein control elements have a through groove and are mounted by engagement elements in the upper area;

(4) FIG. 3 shows a sectional view of the valve drive shown in FIG. 2;

(5) FIG. 4 shows a sectional view of a valve drive according to the invention comprising a switching arrangement, wherein control elements have a formation and are mounted by engagement elements in the middle area;

(6) FIG. 5 shows a further sectional view of the valve drive shown in FIG. 4;

(7) FIG. 6 shows a view of a valve drive according to the invention comprising a switching arrangement, wherein control elements have a formation and are mounted by engagement elements in the upper area;

(8) FIG. 7 shows a sectional view of the valve drive shown in FIG. 6.

DETAILED DESCRIPTION

(9) According to FIG. 1, a valve drive 1 according to the invention has a cam shaft 2 and a cam follower 3 comprising a first roller 3a and comprising a second roller 3b. The cam shaft 2 has a first cam group 4 and a second cam group 5, which are mounted to the cam shaft 2 in a rotationally fixed manner. The first cam group 4 and the second cam group 5 each have a first cam 4a and 5a as well as a second cam 4b and 5b, which is axially adjacent to the respective first cam 4a and 5a. In a first position, the rollers 3a and 3b of the cam follower 3 are drivingly connected to the first cams 4a and 5a of the cam groups 4 and 5, and in a second position, the rollers 3a and 3b of the cam follower 3 are drivingly connected to the second cams 4b and 5b of the cam groups 4 and 5.

(10) To adjust the cam follower 3 into the first position or into the second position, the valve drive 1 has an adjusting device 6, which has a first adjustable engagement element 7a and a second adjustable engagement element 7b. The first engagement element 7a thereby cooperates with a first guide 8a, which is mounted to the cam shaft 2, and the second engagement element 7b cooperates with a second guide 8b of a slide guide 8, which is mounted to the cam shaft 2. The first engagement element 7a and the second engagement element 7b can alternately be adjusted between an initial position and a switching position, whereby there is no contact with the corresponding guide 8a or 8b in the initial position and the respective engagement element 7a or 7b cooperates with the corresponding guide 8a or 8b in the switching position. The valve drive 1 also has a rocker arm 9, on which the cam follower 3 is arranged so as to be capable of being displaced. The rocker arm 9 is rotatably mounted to a rocker arm shaft 10.

(11) To adjust the engagement elements 7a and 7b, the adjusting device 6 has a switching arrangement 11 comprising a first stop area 12a for a first control element 13a and comprising a second stop area 12b for a second control element 13b. In this exemplary embodiment, the switching arrangement 11 is a linearly guided shifting arrangement, which is controlled by means of an individualfor example hydraulic or electromagnetic or pneumaticactuator. In response to a displacement of the switching arrangement 11 along the rocker arm shaft 10, the stop area 12a or 12b is moved to the control element 13a or 13b and the respective control element 13a or 13b is displaced perpendicular to the rocker arm shaft 10 by means of a downwards movement of the rocker arm 9. The adjustment of the control element 13a or 13b with the respective engagement element 7a or 7b thereby occurs in that the control element 13a or 13b abuts on the stop area 12a or 12b of the switching arrangement 11 and is prevented from the upwards or downwards movement of the cam follower 3 with the rocker arm 9 on the rocker arm shaft 10. The control element 13a or 13b is thus adjusted relative to the cam follower 3 in response to the upwards or downwards movement of the cam follower 3 with the rocker arm 9.

(12) The engagement elements 7a and 7b are mounted to the respective control elements 13a and 13b and are adjusted out of the initial position into the switching position in response to the displacement of the control elements 13a and 13b. The adjusted engagement element 7a or 7b now cooperates with the respective guide 8a or 8b, and the cam follower 3 is transferred into the first or into the second position. The control elements 13a and 13b also displace simultaneously with the engagement elements 7a and 7b with the cam follower 3 from the respective stop area 12a or 12b of the switching arrangement 11.

(13) As a whole, the first engagement element 7a and the second engagement element 7b can be controlled by means of the switching arrangement 11 with the control elements 13 and 13b with a single actuator in the valve drive 1 according to the invention. The number of the actuators and thus the total costs of the valve drive 1 are reduced in this way. The switching arrangement 11 can be mounted above or below the cam follower 3 in a space-saving manner by means of the control elements 13a and 13b.

(14) FIG. 2 shows a schematic view of the valve drive 1 and FIG. 3 shows a schematic sectional view of the valve drive 1 illustrated in FIG. 2. The adjusting device 6 in each case has a fastening arrangement 14 comprising a fastening element 15a and comprising a counter fastening element 15b. The fastening element 15a is a through groove, which runs parallel to the longitudinal axis 16 of the respective engagement element 7a and 7b, and the counter fastening element 15b is a formation, which is complementary to the through groove and which is embodied in an integral manner. In this exemplary embodiment, the fastening element 15a is in each case mounted to the control element 13a and 13b, and the counter fastening element 15b is in each case mounted to the engagement element 7a and 7b. The respective control element 13a and 13b is mounted perpendicular to the longitudinal axis 16 of the respective engagement element 7a and 7bthus radiallyto the respective engagement element 7a and 7b by means of the fastening element 15a and the counter fastening element 15b. The mounting of the control elements 13a and 13b parallel to the longitudinal axis 16thus axiallyto the respective engagement element 7a and 7b is realized by means of a stop piece 17 and a stop piece 18 in this exemplary embodiment. For the control elements 13a and 13b, the cam follower 3 also has a guide recess 19a and 19b each, which prevent a lateral rotation of the control elements 13a and 13b on the engagement elements 7a and 7b.

(15) FIG. 4 shows a schematic sectional view of the valve drive 1, and a further schematic sectional view of the valve drive 1, which is illustrated in FIG. 4, comprising the alternatively embodied adjusting device 6, is shown in FIG. 5. Here, the fastening element 15a is a through groove, which is perpendicularthus radialto the longitudinal axis 16 of the respective engagement element 7a or 7b, on the respective engagement element 7a and 7b, and the counter fastening element 15b is an integrally embodied formation on the respective fastening element 13 and 13b. In this exemplary embodiment, the control elements 13a and 13b are mounted in a middle area of the respective engagement elements 7a and 7b. A lateral rotation of the control elements 13a and 13b on the engagement elements 7a and 7b is also prevented here by means of the guide recesses 19a and 19b.

(16) FIG. 6 shows a schematic view and FIG. 7 shows a schematic sectional view of the valve drive 1 comprising the alternatively embodied adjusting device 6. In contrast to the adjusting device 6 in FIG. 4 and FIG. 5, the control elements 13a and 13b are mounted in an upper area of the respective engagement elements 7a and 7b in this exemplary embodiment.

(17) As a whole, the engagement elements 7a and 7b can be controlled securely by means of the switching arrangement 11 with a single actuator in the valve drive 1 according to the invention. The number of the actuators and thus the total costs of the valve drive 1 can thus be reduced. The control of the valve drive 1 is also simplified significantly through this. By means of the control elements 13a and 13b, the switching arrangement 11 can additionally be mounted in the valve drive 1for example to a cylinder headin a space-saving manner.