DE102020104529B4 - Device and method for the mechanical joining of hollow profiles - Google Patents

Abstract

Device for the mechanical joining of hollow profiles, for the positive joining of an inner hollow profile (H2) and an outer hollow profile (H1) arranged coaxially overlapping in a joining area (B), the device having a joining head (1) with a first tool element and a counter-holder (4 ) having a second tool element, wherein the first and second tool element have a mutually corresponding contour, characterized in that
- the joining head (1) has a hold-down package (1.3) adapted to an inner contour of the inner hollow profile (H2) and
- the joining head (1) extends along the longitudinal axis (A) of the hollow profiles (H1, H2) into the joining area (B) and
- the counter-holder in the overlapping joint area (B) rests against the outer hollow profile (H1) for support in such a way that the first and second tool elements are arranged one above the other radially to the longitudinal axis (A) of the hollow profiles (H1, H2) and
- that the first tool element is in the form of a punch (1.1) and the second tool element is in the form of a die (4.1), wherein the punch (1.1) can be moved radially outwards in the direction of the die (4.1) or that the first tool element is in the form a die (4.1) and the second tool element is designed in the form of a punch (1.1), the punch (1.1) being movable radially inwards in the direction of the die (4.1) and
- That the joining head (1) has a first deflection gear (1.2) and that the first tool element can be moved radially by means of the first deflection gear (1.2) and
- The first tool element can be actuated by means of a wedge gear, a camshaft or a hydraulic cushion.

Description

The invention relates to a device and a method for the mechanical joining of hollow profiles and is used in particular for the connection of slender, metallic hollow profiles in mixed construction.

Clinching is a mechanical joining process that creates a primarily form-fitting connection by forming flat sheet metal. With the continuous further development of the clinching process, numerous modified and hybrid variants of this process have emerged. Examples are flat clinching, clinch riveting, clinch gluing, UFBC processes or double-point clinching. These process extensions of clinching aim to improve certain properties of the clinch connection or to influence its production.

Current clinching machines are manufactured as stationary or mobile joining units. In addition to the portal design, C-frame clinching presses are widespread in practice. In order to absorb the high joining forces caused by the process, the machine frame must have a high degree of rigidity in order to reduce the angular distortion of the tools to a minimum. Excessive elastic deformation of the frames increases the angular distortion of the clinching tools. As a result, the quality of the clinching points and the service life of the clinching tools decrease. A high rigidity of the frames ensures the concentricity of the clinching tools, but limits the possible uses of the machines. When clinching hollow profiles, the projection length and the transferable process force of a C-frame clinching press correlate with the achievable diameter and the length of the hollow profile to be connected. Due to this reason, in the case of a C-frame clinching press, the rigidity of the frame must be increased or process forces minimized in order to be able to increase the slenderness (S = L/D) of the hollow profile connection.

From the pamphlets EP 0 890 397 A1 , DE 100 60 035 A1 and DE 101 61 250 B4 Devices and methods for the mechanical joining of sheets, profiles and/or multi-sheet connections are known. Joining devices in C-frame construction are described, which carry out various joining operations in the field of mechanical joining technology by means of a pulsating power stroke.

With the help of the pulsating movement, the required joining force is reduced, which means that the rigidity of the C-frame can be selected to be lower and, in the case of clinching hollow profiles, a greater but still limited degree of slenderness of the hollow profile connection can be achieved.

The pamphlet DE 198 40 780 A1 describes a method and a device for connecting plate-shaped components, which reduces the necessary joining force during clinching due to frictional heat generated by a wobbling movement of the punch. According to the disclosure, the joining force should be reduced by up to 80% compared to the conventional method.

In a further variant of the method, which in the publication DE 101 40 989 C2 is described, the process force during clinching can be reduced by pivoting the punch. Similar to tumbling clinching DE 198 40 780 A1 the process force can be reduced by 75 - 80%.

In the Disclosures DE 10 2004 062 896 A1 and DE 196 30 488 A1 describes a process variant of clinching with a direct or indirect heat source. In the present references, the heat source is provided by resistance or induction heating, among others. The key point of the disclosures is the preheating of critical materials such as magnesium, which do not have the required minimum elongation at break at room temperature. Furthermore, the joining force is reduced due to the heating of the sheet metal pairing.

In the pamphlet DE 195 33 827 C1 a method is described which can join hollow profiles with other workpieces by means of a stamping process using a rod-shaped inner tool, full-circumferential outer tool and a hydraulic working medium. This embossing process is not the clinching joining process, it is only described as "similar to clinching". The joining process is carried out from the inside to the outside. The process is designed for pipe diameters of 10 - 20 mm and, depending on the materials and joint geometry, requires a working pressure of over 1000 bar. However, the method described has the following disadvantages. Due to the hydraulic actuation of the joining stamp, a pressure of over 1000 bar has to be used in order to be able to provide the required joining forces. High-pressure systems always represent a high risk potential. The invention also describes that the inner tool must be 0.1 mm smaller than the pipe to be joined. Associated with this, each pipe diameter requires its own internal tool. As a result, pipe tolerances can hardly be compensated for.

In principle, the methods described above offer the possibility of reducing the required process force and of designing the C-frame of the clinching machine to be less rigid, ie slimmer. As a result, the projection length of the C-frame and the slenderness of the hollow profiles can be increased. Nevertheless, the possibilities of increasing the slenderness by reducing the flexural rigidity are limited. The transmission of the process force via a C-frame from a slenderness degree above 1 does not make sense and should be avoided.

The pamphlet DE 195 33 827 C1 relates to a device for fastening a workpiece to the outer periphery of a closed one-piece profile. The connection of a perforated workpiece with a thin-walled tube with a diameter of 10 to 15 mm is described. The tube is clamped in a split external tool using a clamping screw. An inner tool is inserted into the tube, which completely fills the cross-section of the tube on the inside. The die inserted into the tube is moved by means of a pressurized fluid, creating a connection between the tube and the previously pierced workpiece. Alternatively, a non-pre-drilled flat workpiece is used, with the resulting embossing being created inwardly into the tube. The required forces are generated by means of a high-pressure fluid that is fed into the inner tool to the embossing die.

The object of the invention is to develop a device and a method for the mechanical joining of hollow profiles, which has a simple structural design and achieves a significant increase in the achievable degree of slenderness of hollow profiles, which are joined by clinching. Typical application examples are silencers, ventilation ducts or exhaust systems.

This object is achieved with the characterizing features of the first and ninth patent claims.

Advantageous configurations result from the dependent claims.

The device according to the invention with the associated method represents a new possibility for increasing the degree of slimness.

• - der Fügekopf ein, an eine Innenkontur des inneren Hohlprofiles angepasstes Niederhalterpaket aufweist und
• - der Fügekopf entlang der Längsachse der Hohlprofile bis in den Fügebereich hineinreicht und
• - der Gegenhalter in dem überlappenden Fügebereich an dem äußeren Hohlprofil zur Abstützung anliegt derart, dass das erste und zweite Werkzeugelement radial zu der Längsachse der Hohlprofile übereinanderliegend angeordnet sind und
• - dass das erste Werkzeugelement in Form eines Stempels und das zweite Werkzeugelement in Form einer Matrize ausgebildet ist, wobei der Stempel radial außen in Richtung der Matrize verfahrbar ist oder dass das erste Werkzeugelement in Form einer Matrize und das zweite Werkzeugelement in Form eines Stempels ausgebildet ist, wobei der Stempel radial nach innen in Richtung der Matrize verfahrbar ist und
• - dass der Fügekopf ein erstes Umlenkgetriebe aufweist und dass das erste Werkzeugelement mittels des ersten Umlenkgetriebes radial verfahrbar ist und
• - das erste Werkzeugelement mittels eines Keilgetriebes, einer Nockenwelle oder eines hydraulischen Kissens betätigbar ist.

The device for the mechanical joining of hollow profiles, in particular for the form-fitting joining of an inner hollow profile and an outer hollow profile arranged coaxially overlapping in a joining area, has a joining head with a first tool element and a counter-holder with a second tool element, the first and second tool elements being one in relation to one another have a corresponding contour, where

• - the joining head has a hold-down package adapted to an inner contour of the inner hollow profile and
• - The joining head extends along the longitudinal axis of the hollow profiles into the joining area and
• - The counter-holder in the overlapping joint area rests on the outer hollow profile for support in such a way that the first and second tool elements are arranged one above the other radially to the longitudinal axis of the hollow profiles and
• - that the first tool element is designed in the form of a stamp and the second tool element is designed in the form of a die, wherein the stamp can be moved radially outwards in the direction of the die, or that the first tool element is designed in the form of a die and the second tool element is designed in the form of a stamp , wherein the punch can be moved radially inwards in the direction of the die and
• - That the joining head has a first deflection gear and that the first tool element can be moved radially by means of the first deflection gear and
• - The first tool element can be actuated by means of a wedge gear, a camshaft or a hydraulic cushion.

The joining head is preferably mounted on a tie rod, with the tie rod being rotatable with the joining head. The joining head can thus produce a clinch connection on the circumference of the hollow profile by turning.

The first tool element can be moved radially outwards in the direction of the inner wall of the inner hollow profile by means of the first deflection gear.

The joining head has a second deflection gear, with the hold-down assembly being able to be moved radially outwards by means of the second deflection gear and to be placed against the inner wall of the inner hollow profile. The inner and outer hollow profile are clamped and fixed between the counter holder and the hold-down device.

The hold-down assembly is held by means of at least one snap ring that at least partially encloses the hold-down assembly th, wherein the snap ring is preferably arranged in a circumferential groove.

The die is designed in such a way that it can be adjusted radially. Depending on the configuration, the die can be adjusted radially outwards when assembled as a second tool element and radially inwards when assembled as a first tool element, ie in the joining head.

The die is particularly preferably designed in the form of a circumferential groove, so that the punch only has to be positioned along the longitudinal axis of the device. Exact angular positioning of the punch in relation to an individual die element is not required in this embodiment.

The joining head can also have a number of tool elements which are arranged on the circumference of the joining head. In this way, several clinch connections can be created in one joining process.

The method according to the invention for the mechanical joining of hollow profiles, in particular for the form-fitting joining of an inner hollow profile and an outer hollow profile arranged coaxially overlapping in a joining area, has a counterholder and a joining head, in a first method step the hollow profiles to be joined being overlapped in the counterholder with a second tool element are clamped and the joining head is moved with a first tool element into an end position, so that the first and second tool element are placed coaxially to one another in the joining area. In a second step, a holding-down device is pressed against the inner wall of the inner hollow profile by means of a deflection gear and then, in a third process step, the first tool element is moved to its end position via a push rod and another deflection gear in a path-controlled manner and the clinch connection is established.

The push rod is then retracted, the counterholder is opened and the hollow profile connection can be removed from the machine.

In addition, the variable hold-down device can be used to compensate for pipe tolerances and clamp different pipe cross-sections with one tool. Deformations of the hollow profile are supported by the hold-down device and jamming when the pipe connection is removed is prevented. A high-pressure application is not necessary, since the necessary clinching forces are provided by the translation of the bevel gear.

The invention is explained in more detail below using an exemplary embodiment and associated drawings without being restricted to these.

• 1 eine Darstellung einer Vorrichtung zum Fügen zweier Hohlprofile,
• 2 eine Schnittdarstellung des Fügebereichs der Vorrichtung in einer Ausgangsposition,
• 3 Detailansicht des Fügekopfes,
• 4 eine Schnittdarstellung des Fügebereichs der Vorrichtung in einer eingefahrenen Position,
• 5 eine Schnittdarstellung des Fügebereichs der Vorrichtung in der Fügeposition,
• 6 eine Schnittdarstellung des Fügebereichs der Vorrichtung in einer eingefahrenen Position mit einer Matrize im Fügekopf,
• 7 einen Clinchpunkt am Rundrohr im Schnitt,
• 8 eine Verbindung von zwei Hohlprofilen mittels eines Clinchpunktes,
• 9 eine Verbindung von zwei Hohlprofilen mittels mehrerer umfangsseitig angeordneter Clinchpunkte.

Show it:

• 1 a representation of a device for joining two hollow profiles,
• 2 a sectional view of the joining area of the device in a starting position,
• 3 Detail view of the joining head,
• 4 a sectional view of the joining area of the device in a retracted position,
• 5 a sectional view of the joining area of the device in the joining position,
• 6 a sectional view of the joining area of the device in a retracted position with a die in the joining head,
• 7 a clinch point on the round tube in the cut,
• 8th a connection of two hollow profiles by means of a clinch point,
• 9 a connection of two hollow profiles by means of several circumferentially arranged clinch points.

In 1 a device according to the invention for joining two hollow profiles is shown in a side view. The device has a rotatably mounted and drivable joining head 1 which is connected to a force component 3 by means of a pull rod 2 . The force component is divided into a hydraulic main cylinder 3.1 and a hydraulic cylinder 3.2 for using a hold-down device. A counter-holder 4 is arranged at a distance along the longitudinal axis A in front of the joining head 1 . According to 1 the unit, consisting of the joining head 1, pull rod 2 and force component 3, is arranged on a linear unit 5 so that it can be moved or shifted axially.

2 shows a sectional view of the joining zone with an outer hollow profile H1 and an inner hollow profile H2 arranged in an overlapping manner therein. The overlapping joining area B formed by the inner and outer hollow profile H1, H2 is completely supported from the outside by the counterholder 4 with the second tool element arranged therein in the form of the matrix 4.1 and the hollow profiles H1, H2 are clamped in the counterholder 4. In an initial position, the joining head 1 is moved through the outer hollow profile H1 by means of the linear unit into the position for joining in an end position. The joining head 1 is in a detail view Z in FIG 3 shown. The joining head 1 has a first tool element in the form of a stamp 1.1, which is radial by means of a first deflection gear 1.2 can be moved outwards. The first deflection gear 1.2 is designed in the form of a wedge gear, although other gears, in particular a hydraulic cushion or a camshaft, are also conceivable.
A holding-down device 1.3 is arranged on the circumference of the joining head 1 and can be moved radially outwards by means of a second deflection gear 1.4 in the form of a second wedge gear. The hold-down package 1.3 is fixed in one groove each by means of snap rings 1.5.
The first reversing gear 1.2 has an inner push rod 1.2.1 arranged in the pull rod 2 with a wedge-shaped area 1.2.2 with a carriage 1.2.3 sliding thereon, the stamp 1.1 being formed or mounted on the carriage 1.2.3. A rod-shaped element 1.4.1 with a wedge element 1.4.2 is arranged around the push rod 1.2.1, on which a displaceable element 1.4.3 is arranged, by means of which the hold-down device 1.3 can be moved radially outwards in the direction of the inner wall of the inner hollow profile H2 .

A joining head 1 arranged in the end position is in 4 shown. The associated joining process using the stamp 1.1 is in 5 recognizable. The hold-down package 1.3 rests against the inner wall of the inner hollow profile H2 and presses the hollow profiles H1, H2 against the counter holder 4. In the end position, the punch 1.1 and the die 4.1 are placed coaxially with one another. The die 4.1 is preferably designed in the form of a groove, which means that an exact translational positioning of the punch 1.1 is not necessary. According to the method, after the positioning of the hold-down package 1.3, the inner push rod 1.2.1 and the first deflection gear 1.2 are moved to the end position with the punch 1.1 in a path-controlled manner and the clinch connection of the outer and inner hollow profile H1, H2 is produced. Then the first and second deflection gears 1.2, 1.4 are retracted, the counterholder 4 with the die 4.1 is opened and the hollow profile connection can be removed from the machine.

6 shows an alternative embodiment of the first and second tool element with a joining head 1 in an end position. Also according to 6 are the first and second tool element arranged coaxially to each other. Contrary to the device structure according to the 2 until 5 the matrix 4.1 is integrated into the joining head 1 instead of the stamp. The stamp 1.1 is arranged in the counter-holder 4 in this embodiment.

The 7 shows a hollow profile connection in a sectional view at the clinch point. A hollow profile connection of a first and second round tube is in the 8th and 9 shown. The hollow profile connection is formed from the inner hollow profile H2 and the outer hollow profile H1 and has an undercut 6 at the clinch point, which ensures stability when the hollow profiles are subjected to tensile loads. An undercut is not absolutely necessary for fixing the position.
According to 8th the outer hollow profile H1 is connected to the inner hollow profile H2 by means of a clinch point, according to FIG 9 several clinch points are provided, which are produced individually or in one joining step.

With the method and the device according to the invention, there is for the first time the possibility of clinching hollow profile connections which clearly exceed a slenderness ratio of S>2. Accordingly, 8 mm clinch round points can be realized with the mixed connection AIMg3 and DC04 in the round tube diameter of 60x1 and 58x1 with a slenderness S=5. Such a method can also be transferred to other mechanical joining methods such as punch riveting.

Reference List

1

joining head

1.1

Rubber stamp

1.2

first deflection gear

1.2.1

push rod

1.2.2

wedge-shaped area

1.2.3

Sleds

1.3

hold-down package

1.4

second deflection gear

1.4.1

rod-shaped element

1.4.2

wedge element

1.4.3

movable element

1.5

Snap ring in groove

2

pull bar

3

power component

3.1

hydraulic master cylinder

3.2

hydraulic cylinder

4

counter holder

4.1

die

5

linear unit

6

undercut

A

Longitudinal axis of the hollow profiles/device

B

joining area

H1

Outer hollow profile

H2

Inner hollow profile

Z

detail view

Claims (10)

Device for the mechanical joining of hollow profiles, for the positive joining of an inner hollow profile (H2) and an outer hollow profile (H1) arranged coaxially overlapping in a joining area (B), the device having a joining head (1) with a first tool element and a counter-holder (4 ) with a second tool element, wherein the first and second tool element have a contour that corresponds to one another, characterized in that - the joining head (1) has a hold-down package (1.3) adapted to an inner contour of the inner hollow profile (H2) and - the joining head (1) extends along the longitudinal axis (A) of the hollow profiles (H1, H2) into the joining area (B) and - the counter-holder in the overlapping joining area (B) rests against the outer hollow profile (H1) for support in such a way that the first and second tool elements are arranged one above the other radially to the longitudinal axis (A) of the hollow profiles (H1, H2) and - that the first tool element in in the form of a punch (1.1) and the second tool element in the form of a die (4.1), the punch (1.1) being movable radially outwards in the direction of the die (4.1) or that the first tool element in the form of a die (4.1) and the second tool element is designed in the form of a punch (1.1), the punch (1.1) being movable radially inwards in the direction of the die (4.1) and - the joining head (1) having a first deflection gear (1.2) and the first tool element can be moved radially by means of the first deflection gear (1.2) and - the first tool element can be actuated by means of a wedge gear, a camshaft or a hydraulic cushion. device after claim 1 that the joining head (1) is mounted on a pull rod (2), the pull rod (2) being rotatable with the joining head (1). device after claim 1 or 2 , characterized in that the joining head (1) has a second deflection gear (1.4) and that the holding-down device (1.3) can be moved radially outwards by means of the second deflection gear (1.4) and can be placed against an inner wall of the inner hollow profile (H2). Device according to one of Claims 1 until 3 , characterized in that the hold-down assembly (1.3) is held by means of at least one snap ring (1.5) at least partially enclosing the hold-down assembly (1.3). device after claim 4 , characterized in that the snap ring (1.5) is arranged in a circumferential groove. Device according to one of Claims 1 until 5 , characterized in that the die (4.1) is radially adjustable. Device according to one of Claims 1 until 6 , characterized in that the die (4.1) is designed in the form of a circumferential groove. Device according to one of Claims 1 until 7 , characterized in that the joining head (1) has a plurality of tool elements which are arranged circumferentially on the joining head (1). Method for the mechanical joining of hollow profiles, for the form-fitting joining of an inner hollow profile (H2) and an outer hollow profile (H1) arranged coaxially overlapping in a joining area, having a counter-holder (4) and a joining head (1), characterized in that in a first method step, the hollow profiles (H1, H2) to be joined are clamped in an overlapping manner in the counterholder (4) with a second tool element and the joining head (1) is moved into an end position with a first tool element, so that the first and second tool elements are coaxial with one another in the joining area (B) and that in a second step a hold-down device (1.3) is pressed against the inner wall of the inner hollow profile (H2) by means of a deflection gear and that in a third process step a connecting rod (1.2.1) and a further deflection gear Move the first tool element path-controlled to its end position and the clinch connection is made w ir. procedure after claim 9 , characterized in that the push rod (1.2.1) is retracted, the counter-holder (4) is opened and the hollow profile connection is removed from the device.

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