DE102012207518A1 - Lever-like cam follower - Google Patents

Abstract

Lever-like cam follower for actuating at least one gas exchange valve of an internal combustion engine, having an elongate main body (3) having a bottom (4) and side walls (5) angled therefrom, the bottom (4) being connected to a first end section (6) of the main body (3 ) has a pivot center (9), wherein a middle-near section (7) is provided with a cam roller (12), wherein the cam roller (12) by means of a sliding bearing (13) on a on the side walls (5) supporting the bearing pin (15) is mounted, wherein a first sliding surface (16) of the sliding bearing (13) of the cam roller (12) and a second sliding surface (17) of the sliding bearing (13) the bearing bolt (15) is zugenwandt, wherein the bottom (4) at a second end portion (8) of the base body (3) has a contact surface (11) for a valve stem end of the gas exchange valve, wherein the sliding bearing (13) has a lubricant reservoir (18) to at least one of the sliding surfaces (16, 17) of the sliding bearing s (13) to supply lubricant.

Description

Field of the invention

The invention relates to a lever-like cam follower for actuating a gas exchange valve of an internal combustion engine.

Background of the invention

Lever-like cam followers are arranged in internal combustion engines within a valve train as transmission elements between the cam and the gas exchange valves to be actuated. Lever-like cam followers consist of a lever body, which is supported by means of its one end on a support element and engages with its other end via a contact surface on the gas exchange valve to be opened. In a middle-proximal portion of the lever body, a Nockenabgriffsfläche is provided at the start of a cam of a camshaft during operation of an internal combustion engine and causes a pivotal movement of the finger lever. The Nockenabgriffsfläche may be formed as a sliding surface or as a cam roller.

Under lever-like cam followers, for example, towing levers, rocker arms or rocker arms are to be understood.

From the DE 10 2008 036 056 a cam follower is known, which is designed as a finger lever. The cam roller is disposed in the mid-portion of the finger lever between the side walls. The cam roller is mounted by means of a bearing pin. The cam roller is mounted by means of a plain bearing and guided in a cage needles on the bearing pin.

The DE 10 2005 059 027 A1 discloses a finger follower which provides a lubricant pocket in at least one sidewall. The lubricant bag is used to supply the cam roller with lubricant. The lubricant bag is wedge-shaped.

In the EP 1 554 469 B1 a cam follower of an internal combustion engine is disclosed. In the case of the cam follower, a contact surface for a cam has a microstructure. The microstructure is lattice-like.

Summary of the invention

The object of the present invention is to provide a lever-type cam follower which has an increased service life.

According to the invention, this object is achieved by a lever-like cam follower for actuating at least one gas exchange valve of an internal combustion engine, having an elongated body body having a bottom and angled sidewalls thereof, wherein the bottom at a first end portion of the body has a pivot center, wherein a middle-near section with a Cam roller is provided, wherein the cam roller is mounted by means of a sliding bearing on a bearing on the side walls bearing pin, wherein a first sliding surface of the sliding bearing of the cam roller and a second sliding surface of the sliding bearing faces the bearing pin, wherein the bottom at a second end portion of the base body has a contact surface for a valve stem end of the gas exchange valve, wherein the sliding bearing has a lubricant reservoir to supply at least one of the sliding surfaces of the sliding bearing with lubricant.

Under lever-like cam followers, for example, towing levers, rocker arms or rocker arms are to be understood. In cross-section such cam followers may have a U-shaped, inverted U-shaped or H-like profile. However, the invention is not limited to these types of cam followers. In cam-like cam followers whose cam roller is mounted by means of a sliding bearing on a bearing pin, it can come to the sliding surfaces to adhesive wear or galling. As sliding surfaces of the sliding bearing, on the one hand, the surface is referred to, which is in contact with the cam roller and, secondly, the surface which is in contact with the bearing pin.

In the cam follower according to the invention, a lubricant reservoir is provided in the sliding bearing. This lubricant reservoir serves to supply at least one sliding surface with lubricant. The lubricant reservoir can be provided such that it can supply one of the sliding surfaces or both sliding surfaces with lubricant. Greases or oils can be used as lubricant. Furthermore, solid lubricants, such as graphite, conceivable. The lubricant reservoir ensures a continuous supply of lubricating surface (s) with lubricant. Continuous lubrication reduces wear on the sleeve bearing and cam roller / bearing pin, increasing the life of the lever cam follower.

Alternatively, it is also conceivable that in addition to the sliding bearing a cage occupied with needles can be provided, which supports the cam roller on the bearing pin. This means that one of the sliding surfaces is in contact with the needles. Also in this case, a lubricant reservoir can be provided.

In a preferred embodiment of the invention, the lubricant reservoir is formed by means of at least one channel in the sliding bearing. The at least one channel serves to allow the lubricant to be stored therein. In addition, the at least one channel is arranged in the sliding bearing so that it can supply the entire sliding surface with lubricant. Alternatively, several channels can be provided.

According to one embodiment of the invention, the at least one channel extends starting from at least one end side into the sliding bearing. Such an arrangement of the channel in the plain bearing allows a promotion of the lubricant in these. The front side of the sides of the sliding bearing are referred to, which are respectively facing the side walls. Preferably, the sliding bearing has two end faces. The channel may extend from one end face to another or extend in its direction. It is also possible that the channel starts offset or offset from the front side.

Preferably, the at least one channel is formed by at least one recess. The depression may be formed, for example, as a notch, grooves, beading, pocket (s), groove (s), notch (s) or groove (s) in the sliding surface. For example, the depression may be helical, circumferential or spiral-shaped in at least one of the sliding surfaces. Alternatively, the recess can also be provided radially, axially extending. Furthermore, a change in the flow cross-section of the recess may also be possible. Likewise, a combination of the different wells is conceivable. The recess allows a transport of the lubricant along the entire sliding surface / s.

Preferably, the at least one channel is formed by at least one hole. The channel may also be hole-like or hole-like, formed as a through hole and / or blind hole. The hole can be made by drilling or similar methods.

In one embodiment, the lubricant reservoir of the sliding bearing can be produced by a separation process. The lubricant reservoir can be made for example by turning. This has the particular advantage that the at least one channel in the manufacture of the sliding bearing can be made with.

Preferably, the sliding bearing is made of a metallic material. As metallic materials can u. a. Copper, brass, soft metals or similar materials can be used.

Alternatively, the plain bearing is made of a plastic. As a plastic, PTFE, for example, can be used. However, other plastics are also conceivable.

Alternatively, the slide bearing can be made of ceramic or a ceramic-like material.

According to one embodiment of the invention, the sliding bearing is designed as a sliding ring.

Brief description of the drawings

Hereinafter, an embodiment of the invention will be illustrated with reference to four figures. Show it:

1 a longitudinal section through a lever-like cam follower according to the invention,

2 a detail of a sliding surface with a lubricant reservoir of the lever-type cam follower according to the invention according to a first embodiment,

3 a section of a sliding surface with a lubricant reservoir of the lever-type cam follower according to the invention according to a second embodiment and

4 a section of a sliding surface with a lubricant reservoir of the lever-type cam follower according to the invention according to a third embodiment.

Detailed description of the drawings

The 1 shows a lever-like cam follower according to the invention 1 , which as a rocker arm 2 is trained. The rocker arm 1 has an elongated body 3 on top of a floor 4 and angled sidewalls 5 having. Furthermore, the base body made of a sheet material is 3 in a first end section 6 , a mid-section 7 and a second end portion 8th divided.

The first end section 6 has a pivot center 9 on. The pivot center 9 gets through one in the ground 4 molded dome 10 formed, which is between the side walls 5 rises. The dome 10 serves for support on a supporting element, not shown.

On the second end section 8th of the basic body 3 extending part of the soil 4 is a contact surface 11 provided for an unillustrated valve stem end of a gas exchange valve.

In the area of the middle section 7 is a cam roller 12 intended. The cam roller 12 is by means of a sliding bearing 13 , which as a sliding ring 14 is formed on a bearing pin 15 stored. The bearing bolt 15 is on the sidewalls 5 supported. The sliding ring 14 has a first sliding surface 16 and a second sliding surface 17 on. The first sliding surface 16 is the area of the sliding ring 14 , which is the cam roller 12 is facing. The second sliding surface 17 is the area of the sliding ring 14 , which the bearing bolt 15 is facing. The sliding ring 14 has an in 1 non-visible lubricant reservoir 18 on.

The 2 to 4 each show a section of the sliding surfaces 16 . 17 of the sliding ring 14 , which the lubricant reservoir 18 in three different embodiments show. Basically, the lubricant reservoir through the channels 19 educated. The lubricant reservoir 18 can be on one of the sliding surfaces 16 . 17 or on both sliding surfaces 16 . 17 be provided. To simplify the description, like parts are designated by the same reference numerals.

2 shows the lubricant reservoir 18 according to a first embodiment. The channels 19 of the lubricant reservoir are by a circumferential spiral groove 20 educated. Starting from one of the front sides 21 . 22 the groove runs 20 in the plain bearing 13 or its sliding surface 16 . 17 into it. As a front page 21 . 22 become the sides of the slip ring 14 defines which the sidewalls 5 are facing.

3 shows the lubricant reservoir 18 according to a second embodiment. The channels 19 of the lubricant reservoir 18 are by several circumferentially spaced grooves 23 educated. The grooves 23 extend from the end faces 21 . 22 in the direction of the respective opposite end face 21 . 22 ,

3 shows the lubricant reservoir 18 according to a third embodiment. The channels 19 of the lubricant reservoir 18 are due to several in the sliding surface 16 . 17 provided holes 24 educated. The holes 24 can be formed as through holes and / or blind holes.

The channels 19 serve to supply the sliding surfaces 16 . 17 with lubricant.

LIST OF REFERENCE NUMBERS

1

Lever-like cam follower

2

cam follower

3

lever body

4

ground

5

Side wall

6

first end section

7

middle section

8th

second end section

9

pivoting center

10

dome

11

contact area

12

cam roller

13

bearings

14

sliding ring

15

bearing bolt

16

first sliding surface

17

second sliding surface

18

lubricant reservoir

19

channels

20

groove

21

front

22

front

23

Stichnut

24

hole

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008036056 [0004]
• DE 102005059027 A1 [0005]
• EP 1554469 B1 [0006]

Claims (9)

Lever-like cam follower for actuating at least one gas exchange valve of an internal combustion engine, with an elongate main body ( 3 ), which has a floor ( 4 ) and angled sidewalls ( 5 ), the soil ( 4 ) at a first end portion ( 6 ) of the basic body ( 3 ) a pivoting center ( 9 ), where an intermediate section ( 7 ) with a cam roller ( 12 ), wherein the cam roller ( 12 ) by means of a sliding bearing ( 13 ) on one of the sidewalls ( 5 ) supporting bearing bolts ( 15 ), wherein a first sliding surface ( 16 ) of the sliding bearing ( 13 ) of the cam roller ( 12 ) and a second sliding surface ( 17 ) of the sliding bearing ( 13 ) the bearing bolt ( 15 ), the soil ( 4 ) at a second end portion ( 8th ) of the basic body ( 3 ) a contact surface ( 11 ) for a valve stem end of the gas exchange valve, characterized in that the plain bearing ( 13 ) a lubricant reservoir ( 18 ) to at least one of the sliding surfaces ( 16 . 17 ) of the sliding bearing ( 13 ) to supply with lubricant. Lever-type cam follower according to claim 1, wherein the lubricant reservoir ( 18 ) by means of at least one channel ( 19 ) in the plain bearing ( 13 ) is trained. Lever-type cam follower according to claim 2, wherein the at least one channel ( 19 ) starting from at least one end face ( 21 . 22 ) in the plain bearing ( 13 ) runs. Lever-type cam follower according to claim 2, wherein the at least one channel ( 19 ) is formed by at least one recess. Lever-type cam follower according to claim 2, wherein the at least one channel ( 19 ) through at least one hole ( 24 ) is trained. Lever-type cam follower according to one of the preceding claims, wherein the lubricant reservoir ( 18 ) of the sliding bearing ( 13 ) can be produced by a separation process. Lever-type cam follower according to one of the preceding claims, wherein the plain bearing ( 13 ) is formed of a metallic material. Lever-type cam follower according to one of the preceding claims, wherein the plain bearing ( 13 ) is made of a plastic. Lever-type cam follower according to one of the preceding claims, wherein the plain bearing ( 13 ) as a sliding ring ( 14 ) is trained.

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