Manufacturing method of the main body of the intermediate arm of the variable stroke valve mechanism of an internal combustion engine and the intermediate arm

Abstract

The invention relates to a method for producing a body of an intermediate arm of a variable stroke valve train of an internal combustion engine and to an intermediate arm. The body (1) is formed in one piece from sheet metal and has two spaced-apart side walls (3) with upper portions (4) and lower portions (5) which connect the side walls (3) in a transverse yoke-like manner, which lower portions (5) extend the body (1) with a leg (11, 12) each and have a slide rail (13) on the outside for contact with a valve opener, and wherein on one leg (11) a tongue (19) is sectionally detached from the slide rail (13) and bent in the direction of the upper portion (4) as an abutment for a cam return spring. It is distinguished in that after the blank (14) is punched from a sheet blank, the central base section (15) is formed inwardly to a U-profile section (16) and the slide rail (13) is stamped out, and subsequently the tongue (19) is cut out and bent.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a sheet metal body for the intermediate arm of a variable stroke valve mechanism for an internal combustion engine. Furthermore, this invention also relates to an intermediate arm of a variable stroke valve mechanism for an internal combustion engine having a sheet metal body. Background Technology

[0002] EP 1 573 174 B1 describes an intermediate arm configured for fully variable valve timing with load control without throttling, and describes a method in principle for forming its body from a slab.

[0003] DE 10 2011 003 898 A1 shows another intermediate arm. Here, from Figure 2 It is known that a curved tongue, marked with "21," protrudes little or no beyond the support-like body. This tongue is used to abut the end of a leg extending along the intermediate arm of a torsion spring that serves as a cam return spring for the intermediate arm. In this prior art, the tongue is cut out and bent upright to form a basic profile that is, in principle, support-like, before the slab is deep-drawn and embossed into a U-shaped middle section of the profile.

[0004] CN 206889038 U also reveals a type of intermediate arm used here to be supported on a shaft in a swingable manner via its upper part. Summary of the Invention

[0005] The objective of this invention is to provide a body of a plate-based intermediate arm, or an intermediate arm having a body of plate-based intermediate arm with an optimized tongue.

[0006] According to the present invention, this task is solved by the following method:

[0007] A) A blank is stamped out from a slab, the blank having a central base section, and a wing-shaped protrusion protruding from the side of the base section.

[0008] B) Deep draw the base section into a U-shaped profile section to present the lower support-like base outline, and emboss the slide rail.

[0009] C) Cut the outline of the tongue in the slide rail and bend the tongue off the slide rail and stand it upright. On the one hand, looking along the slide rail towards the other foot, the cutting line for the tongue in the slide rail terminates after the bending radius of the tongue. On the other hand, the length of the tongue is such that the tongue extends beyond the lower part into the longitudinal center area provided for the roller.

[0010] D) Lift up the wing-shaped protrusions to form sidewalls.

[0011] This optimized method allows for the fabrication of the body for the intermediate arm, where relatively low stress is generated in the "connection area" between the tongue and the slide rail. Premature damage to the sheet metal in this area due to twisting, warping, or other reasons is not anticipated. During deep drawing of the base section, it ideally fills its corresponding shape in the mold, creating a transition from the slide rail to its sidewall with a sharp edge. The cutting edge, terminating "after" the starting point of the tongue's bending radius, provides additional elasticity to the significantly longer tongue compared to existing technologies, simply because, when the spring is applied, there is a longer lever arm. The imprinting process of the slide rail can be performed simultaneously or after the deep drawing process. If necessary, the slide rail can also be formed by other methods, such as grinding, performed after step D).

[0012] Therefore, the highlight is that the steps of the method used to date are reversed, in which the tongue is first cut and bent from the slab, and then the base section is drawn into a U-shaped profile section, which will result in high stress in the edge area described above due to material warping, etc.

[0013] If necessary, step D) can also be performed before step C). This has no impact on the quality of the edge region described above.

[0014] This intermediate arm can be widely used due to the extended tongue that intersects the profile of the central roller in the improved embodiments of the invention (two variations). It is particularly suitable for lateral support (keyword: "Auswanderung") of the leg of the torsion spring from now on. However, in some cases, depending on the layout of the valve mechanism, the leg may also be positioned on the tongue along its extension direction.

[0015] Alternatively, this task is accomplished using the intermediate arm of a variable stroke valve mechanism for an internal combustion engine. Accordingly, the transition region of the slide rail leading to the tongue, having a zero-stroke end region, is provided with cutting lines that terminate after the bending radius of the tongue when viewed along the slide rail direction from one leg to the other.

[0016] Therefore, this transition area of ​​the end body with a zero-stroke region, viewed from one foot, possesses a certain elasticity or spring-like characteristic in the longitudinal direction of the arm. This significantly reduces or eliminates the sudden force boost that occurs, for example, in the closing mode of the relevant scavenging valve, when the intermediate arm passes over the rollers forming the end profile of the valve opener using the zero-stroke section of the slide rail. Otherwise, when the rollers (in the direction toward other areas of the carrying stroke curve) pass over the beginning of the "fixed" area of ​​the slide rail, this force boost could cause undesirable loads on the valve springs of the respective (closed) scavenging valves and / or cause a slight "retraction" of the "stiff" hydraulic support elements, because the spherical rollers extend slightly into the free space created by the tongue on one foot.

[0017] Another embodiment relates to a tiered construction scheme in width for the main body or an intermediate arm having the main body. Thus, the main body has the smallest width in the lower, support-like region. The longitudinal central region can correspondingly "bulge" at the rollers (where a sliding surface can be conceived and provided if necessary). Furthermore, the upper section can be widened again relative to the longitudinal central region. The connecting parts are respectively achieved via the sidewall sections of the cranks.

[0018] Finally, it is proposed that the sidewalls are reinforced by transverse yokes that interlock in the upper region. In terms of structural space, it is suitable here that this reinforcement is located on the longitudinal side of the main body facing away from the tongue.

[0019] Arm-shaped cam followers, such as rocker arms or swing arms, are particularly suitable as valve openers loaded by a middle arm, the contact mating element of which relative to the middle arm is typically a roller. However, relative operation on rollers on tappets can also be conceived and implemented. Attached Figure Description

[0020] in:

[0021] Figure 1 A spatial side view of the assembled intermediate arm with the main body is shown.

[0022] Figure 2 The arm is shown upside down as described above;

[0023] Figure 3 The stamped blank is shown;

[0024] Figure 4 The blank shows a deep-drawn base section and a cut slide rail; and

[0025] Figure 5 A blank with a bent tongue and upright sidewalls is shown. Detailed Implementation

[0026] Reference Figure 1 , Figure 2 The complete structure of the intermediate arm 2 with the main body 1 is described.

[0027] The main body 1 is constructed of steel plates. It has two spaced-apart sidewalls 3. These sidewalls open in a forked manner in their upper part 4. The main body 1 is laterally yoke-closed in its lower part 5.

[0028] In the upper part 4, the main body 1 has two holes 6 in which a shaft 8 is housed, bearing a support roller 7, or more precisely, a support roller assembly. The longitudinal central region 9 of the main body 1 houses a roller 10 for relative operation of the stroke cam. The roller 10 runs on a pin 21, which is received in a hole 22 in the longitudinal central region 9.

[0029] As from Figure 1 , 2 It can be seen that the lower part 5 of the main body 1 extends out to support legs 11 and 12 on both sides in the arm swing direction. The lower part 5 thus has a shape similar to a support leg. (If necessary, at least one of the support legs 11 or 12 may only exist initially.)

[0030] The lower part 5 has a grooved rail 13, also known as the working curve, on its free outer side, which is used to contact the rollers that form the end profile of the rocker arm. From Figure 1 From the left-hand support leg 11, a tongue 19 protrudes vertically from the slide rail 13. This tongue extends until it enters a certain height section of the longitudinal central region 9 and... Figure 1 The outline of the roller 10 is shown to intersect with the outline of the roller 10. The free outer side of the tongue 19 acts as a lateral abutment for the leg of the torsion spring, which serves as the cam return spring for the intermediate arm 2. Figure 1 The arrow in the attached figure, marked "10", indicates the direction of force applied by the stroke cam.

[0031] The sidewalls 3 in the upper part 4, on the longitudinal side of the cam force application part in the middle, are reinforced by transverse yokes 18 that originate from these sidewalls and are welded to each other in one piece.

[0032] Reference Figures 3 to 5 The manufacturing method of main body 1 is described:

[0033] First, blank 14 is stamped out from the sheet metal strip. This blank 14 (see...) Figure 3 The base section 15 has a central section, from which a wing-shaped protrusion 20 (the subsequent sidewall 3) protrudes laterally. Then, the base section 15 is deep-drawn into a U-shaped profile section 16 in a die, thereby forming the support-like base profile of the lower part 5. Simultaneously or in a subsequent working step, the profile of the slide rail 13 is embossed.

[0034] like Figure 4 As shown, the tongue 19, which also needs to be bent, protrudes in a finger-like manner from the profile segment 16, or more precisely from its slide rail 13. Two cutouts 17 in the slide rail 13 are prepared for the final bending process that subsequently causes the tongue 19 to "downward" from the completed profile segment 16 (see arrow indication).

[0035] Figure 5 The state of the main body 1, having a tongue 19 that has completed its bending, is disclosed. In this case, Figure 2 The bending radius R of the cutting line 17 in the slide rail 13 at the tongue 19 is shown. B The starting point ends "after". Figure 5 The arrows in the diagram indicate the subsequent step of lifting the wing-shaped protrusions 20 to form the sidewalls 3.

[0036] The aforementioned cut 17, which can be clearly seen from the figure, imparts a certain degree of elastic flexibility to the slide rail 13 in the transition region of the zero-stroke section end area at the tongue 19. The force peak (load of the scavenging valve) that occurs when the intermediate arm 2 rolls over the roller forming the end profile of the rocker arm is greatly reduced or eliminated.

[0037] List of reference numerals

[0038] 1. Main Body

[0039] 2. Intermediate arm

[0040] 3. Sidewalls

[0041] 4 upper part

[0042] 5 lower part

[0043] 6 holes

[0044] 7 Support rollers

[0045] 8 axes

[0046] 9. Vertical central area

[0047] 10 rollers

[0048] 11 legs

[0049] 12 legs

[0050] 13 Slide rail

[0051] 14. Blank

[0052] 15. Basic Section

[0053] 16 profile sections

[0054] 17 Cutting lines

[0055] 18. Transverse yoke

[0056] 19 tongue

[0057] 20 protrusions

[0058] 21 sales

[0059] 22 holes

[0060] R B Tongue bending radius

Claims

1. A method of manufacturing a main body (1) of an intermediate arm (2) of a variable-lift valve train of an internal combustion engine, which main body (1) is formed in one piece from sheet metal and has two spaced-apart side walls (3) with an open upper portion (4) and a lower portion (5) which connects the side walls (3) in a transverse yoke-like manner, the side walls (3) having two bores (6) in the upper portion (4) for either a shaft (8) carrying at least one support roller (7) or for a pivotably mounted bearing on a shaft fixed relative to the cylinder head, wherein The longitudinal central region (9) of the main body (1) is provided for arranging a roller (10) for at least indirect relative running of a cam, wherein the lower part (5) extends the main body (1) on both sides with a foot (11, 12) viewed in the direction of the arm swing, and the lower part has on the outside a slide rail (13) for contact with a valve opener, and wherein on one of the feet (11) a tongue (19) is bent off from the slide rail (13) sectionally and in the direction of the upper part (4) as an abutment for a cam return spring, characterized by the following steps for the manufacture: A) Punching a blank (14) from a sheet blank, which has a central base section (15) from whose side flanks each one wing-like projection (20) projects; B) Deep-drawing the base section (15) into a U-profile section (16) to assume the base contour of the lower part (5) and to stamp out the slide rail (13); C) cutting out the profile of the tongue (19) in the chute rail (13) and bending the tongue (19) away from the chute rail (13) to stand up, wherein, seen in the direction of the chute rail (13) towards the other leg (12), the cutting line (17) for the tongue (19) in the chute rail (13) terminates after the bending radius (R B ) of the tongue (19) and wherein, on the other hand, the length of the tongue (19) is such that the tongue protrudes beyond the lower part (5) into a longitudinal central region (9) provided for the roller (10) and D) Bending up the wing-like projections (20) to form the side walls (3).

2. Intermediate arm (2) of a variable-lift valve train of an internal combustion engine, the main body (1) of which is formed in one piece from sheet metal and has two spaced-apart side walls (3) with an open upper portion (4) and a lower portion (5) which connects the side walls (3) in a transverse yoke, the side walls (3) having two bores (6) in the upper portion (4), which either carry a shaft (8) with at least one support roller (7) or are for a pivotable bearing on a shaft which is fixed relative to the cylinder head, wherein The longitudinal central region (9) of the main body (1) has a roller (10) for at least indirect relative running of the cam, wherein the lower part (5) extends the main body (1) on both sides with a foot (11, 12) viewed in the arm swing direction, and the lower part has on the outside a slide rail (13) for contact with the end profile-forming roller of the valve opener, and wherein from the foot (11) whose section of the slide rail (13) has a zero stroke section, a tongue (19) is bent off sectionally from the slide rail (13) and curved in the direction of the upper part (4) as an abutment for the cam return spring, characterized in that the transition region of the slide rail (13) to the tongue (19) with the zero stroke section end region is provided with a cut line (17) which terminates behind the bending radius (R B ) of the tongue (19) viewed in the slide rail direction from one foot (11) to the other foot (12).

3. The intermediate arm of claim 2, wherein, The main body (1) has a greater width in the longitudinal central region (9) than in the lower part (5).

4. The intermediate arm of claim 2, wherein, The main body (1) has a greater width in the section of the upper part (4) than in the longitudinal central region (9) thereof.

5. The intermediate arm of claim 2, wherein, The tongue (19) extends into the longitudinal central region (9) such that it sectionally overlaps the contour of the roller (10).

6. The intermediate arm of claim 2, wherein, The side walls (3) are reinforced in the upper part (4) by transverse yokes (18) which are welded to one another and which are formed in one piece from the side walls. The side walls (3) are reinforced in the upper part (4) by transverse yokes (18) which are welded to one another and which are formed in one piece from the side walls.

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