DE102021123366A1 - Method of manufacturing a rocker arm for a valve train and rocker arm for a valve train - Google Patents

Abstract

The present invention relates to a method for manufacturing a rocker arm for a valve train and a rocker arm for a valve train. The rocker arm comprises a base plate and side walls (3) arranged opposite one another on both sides thereof, the base plate forming a guide groove (1) at one longitudinal end of the rocker arm for interaction with a valve push rod of the valve train, the method comprising the following steps: S1) punching a sheet metal blank, in a region (3') of the bleaching blank where the side walls are to be formed, in each case recesses (31') are punched out; S2) bending the bleaching slug so that both areas (3') of the side walls to be formed respectively form the side walls (3), the recesses (31') being arranged facing one another; S3) Punching the sheet metal blank to form the guide groove (1), the guide groove (1) and the sections of the two side walls (3) each provided with the recesses (31') essentially forming a W-shape. The rocker arm is manufactured according to the process mentioned above.

Description

technical field

The present invention relates to the field of vehicle technology. More particularly, the present invention relates to a method of manufacturing a rocker arm for a valve train and a rocker arm itself for a valve train.

Technical background

A valve train is usually provided in the internal combustion engine of the current vehicle. The function of the rocker arm in the valve train is to convert the rotary motion of the cam on the camshaft into linear motion, which drives the valve lifter. At present, the main body of the rocker arm, particularly the roller rocker arm, is mostly made by stamping steel sheet.

For example, a roller rocker arm is disclosed in the patent application CN 109944654A disclosed. In this solution, the main body of the roller rocker arm is made of stamped sheet steel. Here, the main body of the rocker arm is approximately U-shaped in cross section and includes a bottom plate and two side walls. The cam on the camshaft makes contact with the rollers in the longitudinal center area of the valve rocker arm, the rollers being rotatably mounted on the two side walls. The valve rocker arm forms a push rod seat for contact with the push rod of the valve train and a push rod seat for contact with the valve push rod of the valve train at both longitudinal ends of the valve rocker arm, with a guide groove being provided on the push rod seat. In this case, the guide groove and the side walls of the main body of the rocker arm form a substantially W-shape in cross section.

However, it has been found that with the above-mentioned type of roller rocker arms, the main body of the rocker arm is easily damaged, particularly at its W-shaped structure.

Presentation of the invention

The object of the present invention is therefore to provide a method for producing a rocker arm for a valve train and a rocker arm for a valve train, wherein the rocker arm provided should have a long service life.

The above object is achieved by a method for manufacturing a rocker arm for a valve train. The aforementioned rocker arm comprises a bottom plate and side walls arranged opposite one another on both sides thereof, the bottom plate forming a guide groove at one longitudinal end of the rocker arm for cooperation with the valve push rod of the valve train.

In this case, the rocker arm preferably comprises a main body made from sheet metal, in particular from sheet steel. The main body of the rocker arm includes a bottom plate and two side walls, wherein the bottom plate and the two side walls enclose a U-shaped structure that extends substantially along the longitudinal direction of the rocker arm. The two side walls of the rocker arm advantageously extend from both sides of the base plate in a direction perpendicular to the extension surface of the base plate. Advantageously and alternatively, the two side walls of the rocker arm preferably extend symmetrically from both sides of the base plate in a direction inclined to the extension surface of the base plate. However, it should be noted that the extension directions of the bottom panel and the side walls are not limited in their respective local areas in the application, that is, the bottom panel and the side walls could have a locally curved structure.

It is particularly preferred that the rocker arm is designed as a roller rocker arm. In this case the rocker arm also comprises rollers, preferably in the form of roller wheels. The rollers are rotatably supported on the main body of the rocker arm, specifically on both side walls of the main body. The axis of rotation of the rollers is perpendicular to the longitudinal direction of the rocker arm. After installing the rocker arm in the valve train, the cam on the camshaft can rest against the rollers.

It is particularly preferred that the main body of the rocker arm, in particular the base plate, forms a tappet seat at one longitudinal end for contact with the tappet of the valve train. The tappet seat is designed, for example, in the shape of a dome.

It is particularly preferred that the main body of the rocker arm, in particular the base plate, forms a push rod seat at the other longitudinal end for contact with the valve push rod of the valve train, a guide groove being provided on the push rod seat.

• S1) Ausstanzen eines Blechrohlings, wobei in einem Bereich des Bleichrohlings, wo die Seitenwände auszubilden sind, jeweils Aussparungen ausgestanzt werden;
• S2) Biegen des Bleichrohlings, sodass beide Bereiche, wo die Seitenwände auszubilden sind, jeweils die Seitenwände des Kipphebels bilden, wobei die Aussparungen in den beiden Seitenwänden einander zugewandt angeordnet sind;
• S3) Stanzen des Blechrohlings, um eine Führungsnut zu formen, wobei die Führungsnut und die jeweils mit Aussparungen versehenen Abschnitte der beiden Seitenwände des Kipphebels im Wesentlichen eine W-Form bilden.

The manufacturing method provided according to the invention comprises the steps:

• S1) Punching out a sheet metal blank, with recesses being punched out in each case in a region of the bleaching blank where the side walls are to be formed;
• S2) bending the bleaching slug so that both portions where the side walls are to be formed respectively form the side walls of the rocker arm, with the recesses in the both side walls being arranged to face each other;
• S3) Punching the sheet metal blank to form a guide groove, the guide groove and the respective recessed portions of the two side walls of the rocker arm forming a substantially W-shape.

In this case, the recesses are preferably formed as recesses countersunk from the surface of the sheet metal blank. In this case, the sheet metal thickness of the sheet metal blank in the recesses is smaller than the sheet metal thickness of the remaining part in the area of the side walls to be formed. Thus, when the relatively extending side walls of the rocker arm are formed by bending the sheet metal blank, the thin-walled portions of the side walls are formed by the recesses. Thus, after the guide groove is formed by punching, the distance between the longitudinally extending side walls of the guide groove and both side walls of the rocker arm is increased due to the provision of the recesses. In this case, particularly, the stress at the junction of the side wall of the guide groove with the thin-wall portion of each side wall of the rocker arm is smaller than in the prior art, which is advantageous for improving the fatigue strength of the main body of the rocker arm.

In addition, since the recesses are provided in the areas where the side walls are to be formed, there is no need to increase the overall width of the rocker arm, i. H. the distance between the opposite side wall surfaces of the two side walls of the rocker arm, to increase the distance between the side wall of the guide groove and the respective side wall of the rocker arm. Likewise, the clear width of the guide groove does not have to be reduced for this. Therefore, the solution according to the invention can be applied to more application solutions and the structural design of the existing valve train can be modified less, so that additional design costs can be saved.

In addition, since the recesses are provided in the area where the side walls are to be formed, the strength in the area of the guide groove to be formed of the sheet metal blank is not impaired, so that the manufacturing process, in particular the stamping process in step S3), is not adversely affected. The strength of the guide groove is not correspondingly reduced, so that the interaction of the guide groove with the valve push rod is not adversely affected during operation.

In a preferred embodiment, the sheet metal thickness of the sheet metal blank in the recesses is 50 to 75% of the sheet metal thickness of the remaining part in the area where the side walls are to be formed. In this preferred arrangement, the beneficial effects in terms of fatigue strength and space size are taken into account. It has been shown that the recesses designed in this way can advantageously reduce the tension, in particular at the connection of the side wall of the guide groove to the respective side wall of the rocker arm.

The sheet metal thickness of the sheet metal blank in the recesses is particularly preferably 60% of the sheet metal thickness of the remaining part in the area where the side walls are to be formed. It has been shown that the recesses designed in this way can advantageously reduce the tension, in particular at the connection of the side wall of the guide groove to the respective side wall of the rocker arm.

In a preferred embodiment, the longitudinal length of the recesses adapts to the longitudinal length of the guide groove. Therefore, over the entire longitudinal extent of the guide groove, the gap formed by the side wall of the guide groove and the two side walls of the rocker arm is always relatively large, so that the stress on the connection of the side wall of the guide groove with the respective side wall of the rocker arm is always lower, which contributes to the improvement the fatigue strength of the rocker arm is advantageous.

The above-mentioned object can also be achieved by a rocker arm for a valve train, which is produced using the method according to one of the above-mentioned embodiments.

character list

• 1 eine perspektivische Darstellung eines Hauptkörpers eines Kipphebels gemäß einer bevorzugten Ausführungsform;
• 2 eine Längsschnittansicht des Hauptkörpers des Kipphebels gemäß 1;
• 3 eine Seitenansicht des Hauptkörpers des Kipphebels gemäß 1; und
• 4 einen im Herstellungsprozess des Kipphebels gemäß 1 ausgestanzten Belchrohling.

The preferred embodiments of the present invention are explained schematically below in connection with the drawings. In the drawings shows:

• 1 12 is a perspective view of a main body of a rocker arm according to a preferred embodiment;
• 2 FIG. 12 is a longitudinal sectional view of the main body of the rocker arm 1 ;
• 3 12 is a side view of the main body of the rocker arm according to FIG 1 ; and
• 4 according to one in the manufacturing process of the rocker arm 1 punched sheet blank.

Description of Preferred Embodiments

1 12 is a perspective view of a main body of a rocker arm according to a preferred embodiment. In this embodiment, the rocker arm is designed as a roller rocker arm. Here the rocker arm includes in addition to the in 1 shown main body rollers (not shown), for example in the form of roller wheels. After installing the rocker arm in the valve train, the cam on the camshaft can rest against the rollers.

As in 1 shown, the main body of the rocker arm is made of sheet steel. Here, the main body of the rocker arm comprises a bottom plate and two side walls 3. The bottom plate and the two side walls 3 form a U-shaped structure extending substantially along the longitudinal direction of the rocker arm. In this embodiment, the two side walls 3 of the rocker arm are parallel to each other. Both side walls 3 are formed with through holes, respectively, and the rollers of the rocker arm may be rotatably supported in the through holes in both side walls 3 by means of a shaft or a pin.

2 FIG. 12 shows a longitudinal sectional view of the main body of the rocker arm according to FIG 1 . As related to 1 and 2 As can be seen, the main body of the rocker arm forms a tappet seat 2 at one longitudinal end of the base plate for contact with a tappet of the valve train. In this embodiment, the tappet seat 2 is designed as a dome. The main body of the rocker arm forms a push rod seat at the other longitudinal end of the base plate for contact with a valve push rod of the valve train.

3 FIG. 12 shows a side view of the main body of the rocker arm according to FIG 1 on the push rod seat side. In connection with 1 and 3 it can be seen that a guide groove 1 is provided on the push rod seat. The two side walls 3 of the rocker arm and the guide groove 1 in the in 3 shown side view and in the corresponding cross-section a W-shape.

• S1) Ausstanzen des Blechrohlings. 4 zeigt den im Schritt S1) ausgestanzten Blechrohling. Wie in 4 gezeigt, werden in einem Bereich 3' des Bleichrohlings, wo die Seitenwände auszubilden sind, jeweils Aussparungen 31' ausgestanzt. Die Aussparungen 31' sind als von der Oberfläche des Blechrohlings versenkte Ausnehmungen ausgebildet. In dieser Ausführungsform beträgt die Blechdicke des Blechrohlings in den Aussparungen 31' 50 bis 75 %, bevorzugt 60 % der Blechdicke des verbleibenden Teils im Bereich 3', wo die Seitenwände auszubilden sind.
• S2) Biegen des Bleichrohlings, sodass der Bereich 3', wo die Seitenwände auszubilden sind, jeweils die Seitenwände 3 des Kipphebels bildet. Dabei sind die Aussparungen 31' in den beiden Seitenwänden 3 einander zugewandt angeordnet. Dadurch werden die dünnwandigen Bereiche 31 in den beiden Seitenwänden 3 durch die Aussparungen 31' gebildet.
• S3) Stanzen des Blechrohlings, um eine Führungsnut 1 zu formen. Die Führungsnut 1 und die jeweils mit Aussparungen 31' versehenen Abschnitte der beiden Seitenwände 3 des Kipphebels bzw. die dünnwandigen Bereiche 31 bilden im Wesentlichen eine W-Form.

The rocker arm shown here can be manufactured, for example, by a manufacturing method of the rocker arm according to a preferred embodiment. The manufacturing process includes the steps:

• S1) Punching out the sheet metal blank. 4 shows the sheet metal blank punched out in step S1). As in 4 1, recesses 31' are punched out in a region 3' of the bleaching slug where the side walls are to be formed. The recesses 31' are designed as recesses countersunk from the surface of the sheet metal blank. In this embodiment, the sheet metal thickness of the sheet metal blank in the recesses 31' is 50 to 75%, preferably 60% of the sheet metal thickness of the remaining part in the area 3' where the side walls are to be formed.
• S2) Bending the bleaching slug so that the area 3' where the side walls are to be formed respectively forms the side walls 3 of the rocker arm. The recesses 31 'in the two side walls 3 are arranged facing each other. As a result, the thin-walled areas 31 in the two side walls 3 are formed by the recesses 31'.
• S3) Punching the sheet metal blank to form a guide groove 1. The guide groove 1 and the sections of the two side walls 3 of the rocker arm, each provided with recesses 31', or the thin-walled areas 31 essentially form a W-shape.

It is conceivable that the manufacturing process of the rocker arm includes other necessary steps: for example, modification of the roller pocket, pressing in of the dome-shaped tappet seat 2 and construction of the through holes in the side walls 3, etc.

With the rocker arm provided in this embodiment and the method for manufacturing the rocker arm, the distance between the longitudinally extending side walls of the guide groove 1 and the thin-walled portions 31 of the two side walls 3 of the rocker arm is larger due to the provision of the recess 31' to relieve the stress at the junction of the side walls of the guide groove 1 with the thin-walled portion 31 of the respective side wall 3 of the rocker arm is smaller than in the known solution, which is advantageous for improving the fatigue strength of the main body of the rocker arm.

In addition, it is not necessary to increase the total width W ₁ (see 3 ) of the rocker arm and/or the clear width W ₂ (see 3 ) of the guide groove 1 to increase the distance between the side wall of the guide groove 1 and the respective side wall 3 of the rocker arm. Therefore, the solution according to the invention can be applied to more application solutions and the structural design of the existing valve train can be modified less, so that additional design costs can be saved. In addition, since the recesses 31' only in the area 3' where the side walls are formed are provided, the strength in the region 1 ′ of the sheet metal blank where the guide groove is to be formed is not impaired, so that the stamping process in step S3) is not adversely affected. The strength of the guide groove 1 is not correspondingly reduced, so that the interaction of the guide groove 1 with the valve push rod is not adversely affected during operation.

Although possible exemplary embodiments are described by way of example in the above description, it goes without saying that there are still a large number of exemplary embodiments due to all the known and otherwise easily imaginable technical features and combinations of the exemplary embodiments. Additionally, it should be understood that the exemplary embodiments are provided by way of example only, and these embodiments do not limit the scope, application, and configuration of the present invention in any way. Rather, the foregoing description is intended to provide technical guidance for technical personnel to modify at least one embodiment, while various changes can be made as long as they do not depart from the scope of the claims, in particular the changes in the function and structure of components .

Reference List

1

guide groove

2

dome

3

Side wall

31

thin-walled area of the sidewall

1'

Area where the guide groove is to be formed

3'

Area where the side walls are to be formed

31'

recess

w1

Overall width of the rocker arm

W2

Clear width of the guide groove

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was 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.

Patent Literature Cited

• CN109944654A [0003]

Claims (5)

Method for manufacturing a rocker arm for a valve gear, the rocker arm comprising a base plate and on both sides thereof oppositely arranged side walls (3), the base plate forming a guide groove (1) at one longitudinal end of the rocker arm for cooperation with a valve push rod of the valve gear, characterized characterized in that the method comprises the following steps: S1) punching out a sheet metal blank, with in each case recesses (31') being punched out in a region (3') of the bleaching blank where the side walls are to be formed; S2) bending the sheet metal blank so that both regions (3') where the side walls are to be formed form the side walls (3), respectively, with the recesses (31') arranged to face each other; S3) Punching the sheet metal blank to form the guide groove (1), the guide groove (1) and the sections of the two side walls (3) each provided with the recesses (31') essentially forming a W-shape. procedure after claim 1 , characterized in that the sheet metal thickness of the sheet metal blank in the recesses (31') is 50 to 75% of the sheet metal thickness of the remaining part of the area (3') where the side walls are to be formed. procedure after claim 2 , characterized in that the sheet metal thickness of the sheet metal blank in the recesses (31') is 60% of the sheet metal thickness of the remaining part in the region (3') where the side walls are to be formed. Procedure according to one of Claims 1 until 3 , characterized in that the longitudinal length of the recesses (31 ') is adapted to the longitudinal length of the guide groove (1). Rocker arm for a valve train, wherein the rocker arm according to the method of one of Claims 1 until 4 will be produced.

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