Connecting rod for an internal combustion engine with variable compression

Abstract

A connecting rod for an internal combustion engine with variable compression, the connecting rod including an eccentrical element adjustment arrangement configured to adjust an effective connecting rod length, wherein the eccentrical element adjustment arrangement includes an eccentrical element that cooperates with an eccentrical element lever and supports rods that engage the eccentrical element lever, and wherein the eccentrical element lever is integrally configured in one piece as a stamped and bent component or fabricated by a massive cold forming method.

Claims

1. A connecting rod for an internal combustion engine with variable compression, the connecting rod comprising: an eccentrical element adjustment arrangement configured to adjust an effective connecting rod length, wherein the eccentrical element adjustment arrangement includes an eccentrical element that cooperates with an eccentrical element lever and supports rods that engage the eccentrical element lever, and wherein the eccentrical element lever is integrally configured in one piece as a stamped and bent component or fabricated by a massive cold forming method, wherein the eccentrical element lever includes joint receivers that are engageable by ball joints of the support rods, wherein the joint receivers are configured as an embossing in the eccentrical element lever, wherein a connecting rod bearing eye and the eccentrical element include first portions with first face contours, wherein the eccentrical element lever envelops the eccentrical element exclusively in the first portions of the eccentrical element wherein the first portions of the eccentrical element are arranged on both axial sides of the eccentrical element with respect to an eccentrical element rotation axis and extend over half or less of a circumference of the eccentrical element.

2. The connecting rod according to claim 1, wherein at least a portion of the eccentrical element lever is subjected to a directional change in a forming process.

3. The connecting rod according to claim 1, wherein at least a portion of the eccentrical element lever includes at least two forming radii in planes that are arranged at a slant angle relative to each other.

4. The connecting rod according to claim 1, wherein the eccentrical element lever includes at least one loss prevention safety that secures the support rods against falling out of the eccentrical element lever.

5. The connecting rod according to claim 1, wherein the joint receivers are configured as spherical shell sections.

6. The connecting rod according to claim 1, wherein the eccentrical element lever includes recesses configured to safe weight and reduce tensions.

7. The connecting rod according to claim 1, wherein the eccentrical element lever includes connection sections that are parallel to each other and that are connected torque proof with the eccentrical element.

8. The connecting rod according to claim 7, wherein the connection sections have a cambered inner surface which is configured as a circular arc segment and which envelops the first portions.

9. The connecting rod according to claim 8, wherein the cambered inner surface includes a circular arc shaped segment that is configured at the most as a semi-circle.

10. The connecting rod according to claim 8, wherein the eccentrical element lever is welded together with the eccentrical element along the inner surface.

11. An internal combustion engine, comprising: at least one connecting rod according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages can be derived from the subsequent description of an advantageous embodiment with reference to drawing figures, wherein:

(2) FIG. 1 illustrates an isometric view of a known connecting rod for an internal combustion engine with variable compression;

(3) FIG. 2 illustrates an isometric view of a connecting according to an embodiment of the invention;

(4) FIG. 3 illustrates an isometric view from a bottom side of the eccentrical element lever according to FIG. 2;

(5) FIG. 4 illustrates a side view of the eccentrical element lever according to FIG. 2;

(6) FIG. 5 illustrates a front view of the eccentrical element lever according to FIG. 2;

(7) FIG. 6 illustrates a top view of the eccentrical element lever according to FIG. 2;

(8) FIG. 7 illustrates an isometric view of an eccentrical element lever according to another embodiment of the invention;

(9) FIG. 8 illustrates an isometric view of the eccentrical element lever according to FIG. 7 from a bottom side;

(10) FIG. 9 illustrates a side view of the eccentrical element lever according to FIG. 7;

(11) FIG. 10 illustrates a front view of the eccentrical element lever according to FIG. 7;

(12) FIG. 11 illustrates a top view of the eccentrical element lever according to FIG. 7;

(13) FIG. 12 illustrates an isometric view of the eccentrical element lever according to another embodiment of the invention;

(14) FIG. 13 illustrates a side view of the eccentrical element lever according to FIG. 12;

(15) FIG. 14 illustrates a bottom view of the eccentrical element lever according to FIG. 12;

(16) FIG. 15 illustrates a top view of the eccentrical element lever according to FIG. 12;

(17) FIG. 16 illustrates a front view in the direction XVI of the eccentrical element lever according to FIG. 13;

(18) FIG. 17 illustrates a front view in the direction XVII of the eccentrical element lever according to FIG. 13;

(19) FIG. 18 illustrates a top view of a punched out blank of an eccentrical element lever according to FIG. 7;

(20) FIG. 19 illustrates an isometric view of the punched out blank according to FIG. 18;

(21) FIG. 20 illustrates a front view of the blank according to FIG. 18 after a bending process;

(22) FIG. 21 illustrates a side view of the blank according to FIG. 18 after the bending process;

(23) FIG. 22 illustrates a top view of the blank according to FIG. 18 after the bending process;

(24) FIG. 23 illustrates an isometric view of the blank according to FIG. 18 after the bending process;

(25) FIG. 24 illustrates a bottom view of the blank according to FIG. 18 after the bending process and subsequent embossing of joint receivers;

(26) FIG. 25 illustrates a side view of the blank according to FIG. 24;

(27) FIG. 26 illustrates a top view of the blank according to FIG. 24;

(28) FIG. 27 illustrates an isometric view of the blank according to FIG. 24;

(29) FIG. 28 illustrates an isometric view of a bottom side of the blank according to FIG. 24;

(30) FIG. 29 illustrates a front view of the blank according to FIG. 24;

(31) FIG. 30 illustrates a top view of a bottom side of the blank after finishing;

(32) FIG. 31 illustrates a side view of the blank according to FIG. 30;

(33) FIG. 32 illustrates a top view of the blank according to FIG. 30;

(34) FIG. 33 illustrates an isometric view of the blank according to FIG. 30;

(35) FIG. 34 illustrates an isometric view from a bottom side of the blank according to FIG. 30; and

(36) FIG. 35 illustrates a front view of the blank according to FIG. 30.

DETAILED DESCRIPTION OF THE INVENTION

(37) In the drawing figures identical or like components are designated with identical reference numerals. According to an advantageous embodiment the eccentrical element lever. The drawing figures merely illustrate exemplary embodiments and do not limit the spirit and scope of the invention,

(38) FIG. 1 illustrates a known connecting rod 1 for an internal combustion engine with variable compression. The connecting rod 1 includes an upper wrist pin bearing eye 2 into which a risk pin is inserted that is not illustrated in detail. The wrist pin is firmly inserted into the combustion chamber piston of the internal combustion engine in a typical manner. The wrist pin bearing eye 2 is pivotable by an eccentrical element adjustment arrangement 3 about a pivot axis that is oriented parallel offset to the longitudinal axis of the wrist pin bearing eye 2. Thus, it is possible to adjust the wrist pin bearing eye 2 with respect to its distance from a center axis of the crank bearing 35. This facilitates implementing a variable compression of the combustion chamber of the internal combustion engine.

(39) An adjustment travel of the eccentrical element adjustment arrangement 3 which includes a multi-component eccentrical element lever 12 including two eccentrical element lever segments 5, 6 and an eccentrical element 4 that cooperates with the eccentrical element lever 12 and that is supported in a connecting rod bearing eye 20 of the eccentrical element lever is adjustable by a switch valve that is not illustrated.

(40) A rotation of the adjustable eccentrical element adjustment arrangement 3 is initiated by am impact of mass and load forces of the internal combustion engine that act upon the eccentrical element adjustment arrangement 3 during an operating stroke of the internal combustion engine. Effective directions of forces acting upon the eccentrical element adjustment arrangement 3 change continuously during an operating stroke. The rotating movement or adjustment movement is supported by one or plural pistons that are loaded with hydraulic fluid in particular with motor oil, integrated in the connecting rod 1 and not illustrated or the pistons prevent a resetting of the eccentrical element adjustment arrangement 3 due to varying force effective directions of forces impacting the eccentrical element adjustment arrangement 3.

(41) The pistons are respectively movably supported in a cylinder bore hole of a hydraulic cylinder of a connecting rod body 9 of the connecting rod 1 and connected with support rods (eccentrical element rods) 7, 8 which are in turn pivotably linked at the eccentrical element lever segments 5, 6 by cylindrical bolts 10.

(42) Three embodiments of an eccentrical element lever 12 of a connecting rod 1 according to the invention can be derived from FIGS. 2-17.

(43) According to the invention it is provided that the eccentrical element lever 12 is integrally configured as a stamped and bent component or produced by a massive cold forming method.

(44) FIG. 2 illustrates an isometric view of an eccentrical element lever 12 according to a first embodiment of the invention whereas FIG. 3 illustrates an isometric view from a bottom side, FIG. 4 illustrates a side view of the eccentrical element lever, FIG. 5 illustrates a front view and FIG. 6 illustrates a top view of the eccentrical element lever.

(45) FIGS. 2-6 illustrate various views of the eccentrical element lever 12 configured as a stamped and bent component. Joint receivers configured as spherical shell sections that are engaged by ball joints of the eccentrical element rods 7, 8 are embossed in the eccentrical element lever 12 without chipping fabrication and advantageously calibrated.

(46) The eccentrical element lever 12 includes a loss safety 30 which secures the support rods 7, 8 against falling out of the eccentrical element lever 12. A wrist pin solution can be provided as a loss prevention safety 30 as indicated by the openings 15, 16. Alternatively lobes can be formed at the eccentrical element lever 12 wherein the lobes are bent over or crimped after insertion of the eccentrical element levers 7, 8 and thus respectively envelop the ball head of the eccentrical element rod 7, 8 at least partially. As an additional alternative the loss prevention safety 30 can include lobes with elbows into which the ball joints of the support rods 7, 8 are insertable.

(47) As evident e.g. from FIG. 2 and FIG. 4 the eccentrical element lever 12 can include recesses 17, 18 in order to save weight and reduce stress.

(48) The eccentrical element lever 12 includes connection sections 31, 32 that are parallel to each other and that are connected torque proof with the non-illustrated eccentrical element 4. The eccentrical element lever segment 5 thus includes the connection section 32 whereas the eccentrical element lever segment 6 includes the connection section 31. The eccentrical element 4 can be welded together e.g. with the connecting rod bearing eye 20 of the eccentrical element lever 12.

(49) In the eccentrical element lever 12 the connecting rod bearing eye 20 and the non-illustrated eccentrical element 4 include first portions 24, 25 with first face contours 37, 38 and second portions 26, 27 with second face contours 39, 40, wherein the eccentrical element lever 3 envelopes the eccentrical element 4 in both portions 24, 25 and 26, 27 of the eccentrical element 4.

(50) FIG. 7-11 illustrate another embodiment of a one piece eccentrical element lever 12 which is configured as a stamped and bent component.

(51) FIG. 7 illustrates an isometric view of the eccentrical element lever 12, whereas FIG. 8 illustrates an isometric view, FIG. 9 illustrates a side view, FIG. 10 illustrates a front view and FIG. 11 illustrates a top view of the eccentrical element lever 12 according to FIG. 7.

(52) Differently from the previously described embodiment it is provided that the connecting rod bearing eye and the non-illustrated eccentrical element 4 include first portions 24, 25 with first face contours 37, 38 and second portions 26, 27 with second face contours 39, 40, wherein the eccentrical element lever 3 envelopes the eccentrical element 4 in this embodiment exclusively in the first portion 24, 25 of the eccentrical element 4.

(53) The eccentrical element lever 12 includes connection sections 31, 32 that are parallel to each other and that are connected torque proof with the non-illustrated eccentrical element 4. The connection sections 31, 32 include a cambered inner surface 33, 34 which is configured as a circular arc segment and which envelops the first portion 24, 25. The inner surface 33, 34 includes a circular arc segment that is configured as a semi-circle at the most. The eccentrical element lever 3 can be advantageously welded to the eccentrical element 4 along the inner surface 33, 34.

(54) Advantageously the connection sections 31, 32 can be configured thinner in a portion of ends of the weld seam when connecting an eccentrical element 4, than in other portions of the connection sections 31, 32 in order to keep the load that is caused in an end portion of the weld seam by the force introduction small. Thus, a risk of a fracture forming in the weld seam can be reduced.

(55) A third embodiment can be derived from FIGS. 12-17 which shows a single piece eccentrical element lever 12 configured as an investment cast component.

(56) FIG. 12 illustrates an isometric view of the eccentrical element lever 12, whereas FIG. 13 illustrates a side view, FIG. 14 illustrates a view from a bottom side of the eccentrical element lever 12, FIG. 15 illustrates a top view of the eccentrical element lever 12, FIG. 16 illustrates a front view from the direction XVI of the eccentrical element lever 12 according to FIG. 13 and FIG. 17 illustrates a front view from the direction XVII of the eccentrical element lever according to FIG. 13.

(57) Also in this embodiment the eccentrical element lever 12 is implemented as a component that is fabricated integrally in one piece. It is evident that also this embodiment includes a non-symmetrical eccentrical element lever 12 which is structurally optimized with respect to forces that impact it during operations of the internal combustion engine. Transversal bore holes configured as openings 15, 16 for receiving loss prevention safeties e.g. provided as safety pins are arranged in the eccentrical element lever 12 in the portions of the joint receivers 13, 14 (c.f. FIG. 14).

(58) In the bottom view in FIG. 14 the two joint receivers 13, 14 are shown which are also at least visible in the two front views in FIGS. 16, 17 from various sides of the eccentrical element lever 12.

(59) Alternative embodiment provide that the one piece eccentrical element lever 12 is produced by a massive cold forming process or as a laser cut and subsequently bent component.

(60) FIGS. 18-35 illustrate an eccentrical element lever 12 that is fabricated as a stamped and bent component which corresponds to the embodiment illustrated in FIGS. 7-11 in various fabrication steps.

(61) FIG. 18 illustrates a top view of the stamped blank 42 of an eccentrical element lever 12 that is illustrated e.g. in FIGS. 7-11 in a finished condition. The blank 42 can be configured e.g. as a stamped sheet metal component. High strength case hardened steel can be used for example for a material of the eccentrical element lever 12, wherein the hardening can be performed before or after the forming. FIG. 19 illustrates an isometric view of the stamped blank 42.

(62) FIG. 18 illustrates the flat stamped blank 42 configured as a sheet metal component with indicated creasing lines 50, 51, 52, 53, 54, 55. The creasing lines 50, 51, 52, 53, 54, 55 are respectively arranged symmetrical to a symmetry axis L of the blank 42. The blank 42 is creased in subsequent bending processes along these predetermined creasing lines 50, 51, 52, 53, 54, 55 into the desired shape of the eccentrical element lever 12. Thus, at least a portion 28, 29 of the eccentrical element lever 12 is at least subjected to a directional change during the forming process. The portions 28, 29 can also be advantageously subjected to plural directional changes during the forming process as indicated in the illustrated embodiment. The portions 28, 29 of the eccentrical element lever 12 include at least two different forming radii 21, 22, in particular in planes that are arranged at a slant angle relative to each other.

(63) The creasing lines 50, 51, 52, 53, 54, 55 can be configured pre-embossed in order to facilitate the creasing process.

(64) FIG. 20 illustrates a front view of the blank 42 according to FIG. 18 after the bending process, whereas FIG. 21 illustrates a side view, FIG. 22 illustrates a top view, and FIG. 23 illustrates an isometric view after the creasing process.

(65) After the creasing process the blank 42 is already brought into the desired shape of the eccentrical element lever and can then be processed further.

(66) FIG. 24 illustrates a bottom view of the blank 42 according to FIG. 18 after the creasing process and subsequent embossing of joint receivers. FIGS. 25-29 illustrate different views of the blank 42 in this condition.

(67) The joint receivers 13, 14 are embossed from a bottom side of the blank 42 into the blank 42 as spherical shell sections. Therefore the two joint receivers 13, 14 are visible as rises of the eccentrical element lever 12 in the side view in FIG. 25. The joint receivers can be used as bearings for the ball joints of non-illustrated support rods 7, 8 of the connecting rod 1.

(68) FIGS. 30-35 illustrate the finished eccentrical element lever 12 which corresponds to the embodiment illustrated in FIGS. 7-11. FIG. 30 illustrates a bottom view of the eccentrical element lever 12 according to FIG. 18 after finishing. FIGS. 31-35 illustrate various views of the eccentrical element lever 12 after finishing.

(69) The eccentrical element lever 12 includes transversal bore holes in the portion of the joint receivers 13, 14 that are configured as openings 15, 16 for receiving loss prevention safety elements e.g. configured as safety pins. Alternatively a loss safety can also be provided in a form of a crimped or bent over lobe in the portion of the joint receiver 13, 14 which can secure a ball joint of a support rod against sliding out of the joint receiver.