EP3071348B1 - Tool for attaching a joining element to a component section - Google Patents

Description

State of the art

Devices or tools for attaching joining elements to components are known, for example riveting tools. With such tools, joining elements such as semi-hollow punch rivets, solid punch rivets or clinch rivets can be processed. The joining elements provided for a joining point on the component must be moved towards the component from a presentation position on or in the tool before they are attached to the component.

The generic WO 01/97999 A2 relates to a rivet carrier with a drive for introducing rivet elements into a workpiece.

the DE 10 2008 051 488 A1 focuses on a setting device for an auxiliary joining part, with a stamp that can be moved for a setting movement and to which the auxiliary joining part can be fed loosely.

Object and advantages of the invention

The object of the present invention is to improve the tools mentioned in the introduction, in particular with regard to providing joining elements on the tool in a space-saving manner that is not critical in terms of malfunctions. This object is achieved by the independent claim.

The dependent claims relate to advantageous variants of Invention.

The invention is based on a device for attaching a joining element to a component section for a tool for attaching a joining element to a component section with a linearly movable punch, with which a joining element presented in a template position can be moved from the template position to the component section.

In particular, the invention relates to a device for a joining or riveting tool for semi-tubular punch riveting, solid punch riveting, clinch riveting or for processing other joining elements.

Such tools comprise a punch arrangement with a driven, linearly movable punch element or punch, usually with a hold-down device provided on the outside around the punch, and a die unit arranged opposite. The component section is positioned between the punch arrangement and the die unit, for example two or more layers of sheet metal and/or other materials for attaching the joining element. According to the invention, the stamp picks up a joining element waiting in the template position for further processing from a retracted position and guides the joining element to the joining point on the component section, where it is firmly anchored to the component section, for example pressed in.

The tools in question are often designed with a C-shaped tool part or a so-called C-frame, which includes the punch arrangement and the die unit.

A component section can be understood, for example, as sheet-like components, for example single-layer or multi-layer flat components. If necessary, two or more component layers can be connected to one another with the tool.

The core of the invention lies in the fact that means for providing a pressure difference in the range of a provided joining element are present, wherein the pressure difference that can be provided with the means on a provided joining element causes a holding force to act on the joining element, so that the joining element is held in a fixed position in the presentation position.

In this way, a joining element on the tool is advantageously held in the presentation position. According to the invention, an arrangement is proposed which, as far as a free movement path of the stamp is concerned, does not have any critical interfering contours due to holding mechanisms for the joining element. According to the invention, to realize the pressure difference, neither components or elements that can be moved to the template position are necessary nor present, as is the case with known arrangements. These elements repeatedly lead to collisions with the moving stamp.

In addition, the pressure difference can advantageously be realized in particular with a pneumatic arrangement that is often present. Pneumatic arrangements are regularly required for riveting or joining tools, for example for transporting joining elements from a store or a template for a plurality of joining elements to the tool.

According to the invention, the joining element held with the pressure difference is pressed or sucked against a mechanical stop. The mechanical stop is matched to a section of an external shape of the joining element, which comes into contact with the stop in the forward position of the joining element, whereby positive locking or surface contact additionally acts as a pressure in this area of contact, supporting or increasing a holding function for the joining element.

The pressure difference acting on the joining element can be established, for example, by increasing or reducing air pressure in the vicinity of the joining element in the template position. The pressure difference is static or dynamic or provided by a gas flow.

It is also according to the invention that there are flow means for providing a directed gas flow in the area of a joining element that has been placed, the gas flow flowing around the joining element in such a way that a holding force can be provided on the joining element, which holds the joining element in the feeding position.

The joining element is pushed into the desired template position by the gas flow or pneumatically and remains held there. The directed gas flow causes in particular a force acting on the joining element in such a way that the joining element is prevented from being displaced or moved away from the original position due to gravity or the joining element's own weight.

The directed gas flow is in particular horizontal or, according to the invention, is directed transversely to a vertical direction of movement of the stamp. As a rule, a joining element is held in the template position with its longitudinal axis aligned or offset parallel to the longitudinal or movement axis of the stamp. The stamp is in a retracted position relative to the component section, so that the joining element is held between the front end of the retracted stamp and the component section in a waiting or presentation position or pick-up position. The gas flow on the joining element can accordingly z. B. transversely or obliquely to the direction of movement of the punch or the longitudinal axis of the joining element on the joining element. In the direction of flow of the gas stream after or behind the joining element or optionally to the side of it, it is advantageous to provide volume areas or outflow paths for outflow or discharge of the gas stream.

From the template position, the supplied joining element can be moved towards the component section by a linear forward movement of the stamp. The stamp overcomes the holding force on the joining element and takes it with it by pushing it along.

It cannot be ruled out that the gas stream will change its outflow path the moment it reaches the template position. This can be the case, for example, if the outflowing gas flow is discharged behind the joining element via an outflow opening, but the outflow opening is closed when the joining element reaches the forward position. From this moment on, the gas flow is guided past the side of the joining element via other discharge paths, for example. If the joining element is then taken along by the stamp, the outflow opening is also released again, with the next joining element being pushed into the template position by the gas flow.

If necessary, it can be set up that a low pressure or negative pressure is applied in the closed outflow opening, whereby a negative pressure or suction holding force acts on the joining element in the template position in this area.

According to the invention, a wall section that reaches an area that can be occupied by a joining element in the presentation position is designed such that a joining element that reaches the presentation position assumes the presentation position correctly aligned under the effect of the gas flow. The joining element is transported to the presentation position, for example via a conveying line, in such a way that the joining element already reaches the region of the presentation position in at least approximately the correct position. The wall section can be adjusted in such a way that under the effect of the pressure difference or the gas flow on the outside of the joining element, the latter assumes the original position in the exact desired alignment via punctiform, linear and/or surface contact with the wall section.

It is also according to the invention that the wall section is designed to match an outer contour of the joining element. If the wall section in question is designed to match the corresponding area of the outer contour of the joining element or, for example, forms its negative shape, the joining element can be brought under the action of the gas flow exactly into the desired template position, in which the section of the outer contour of the joining element fits perfectly or possibly lies flat against the wall section.

It is also according to the invention that the inflow means are designed to move a joining element with the aid of the gas flow from one end of a feed section, with which a joining element can be fed to the device by line, to the presentation point. In addition to providing the holding force, the gas flow is advantageously used as a transport medium for the directed movement of a joining element in order to transport it from an end of a conveying line that reaches the device or the tool to the presentation position. This is usually a comparatively short distance. Advantageously, the transport of the joining elements in the conveying line also takes place pneumatically or under the action of a directed gas flow. This gas flow is then also used to hold the respective joining element in the original position.

An alternative advantageous variant of the invention is characterized in that in a region in which a joining element assumes the template position, there are discharge sections for guiding away the directed gas flow. In this way, the gas flow can be guided past the joining element in the template position in a targeted manner so that the holding force is optimized.

The discharge section can be formed on a rear side of the held joining element in relation to the inflow direction of the gas flow, for example as at least one discharge line for the gas flow.

The flow of gas is preferably from the direction from which the joining element is transported via a feed line to the presentation position. In this way, the joining element reaches the template position in the direction of the conveying movement.

It is also advantageous that there is a negative pressure arrangement for generating a gas negative pressure in the area of the template position. For example, a negative pressure or vacuum pump can be provided, which generates a negative pressure in the area of the receiving position, for example in a low-pressure borehole reaching up to the receiving position, or sucks off the air present there. The negative pressure must be set up in such a way that a resultant suction force acting on the joining element pulls the joining element into the presentation position.

The vacuum arrangement can advantageously be designed to check the presence of a joining element with respect to the template position. In addition to the holding function or as an alternative to the holding function, the vacuum arrangement can serve to check whether a joining element is present or is present correctly at the template position. This can be done, for example, with an arrangement which z. B. a sensor and / or a pressure switch for measuring a vacuum or low pressure in a low-pressure bore, which reaches up to the joining element in the presentation position. The arrangement in question can determine whether a semi-tubular punch rivet is located under the punch or in the template position or not.

For example, combined with a holding function by low pressure, a presence check for a presented joining element can be provided.

It is also advantageous that there is an overpressure arrangement for generating an overpressure of gas in the area of the template position. The overpressure is preferably set up in such a way, for example with a pneumatic arrangement, that a resultant compressive force acting on the joining element forces the joining element into the presentation position. The excess gas pressure is advantageously set up with a specifically aligned gas flow, in particular with a continuous and/or constant gas flow or air flow.

It is also advantageous that the inflow means are designed to generate a gas stream, so that gas flows towards a joining element present in the presentation position. In this way, the holding force can be realized permanently, especially in a reproducible manner. Advantageously, an overpressure can be generated in the area of the template position via the gas stream in order to provide the desired or necessary holding force acting on the joining element. With a greater weight of the joining element, a correspondingly higher holding force can be set up than with a lighter joining element, in which case a lower gas volume flow or gas overpressure compared to the heavier joining element may be sufficient under otherwise identical conditions.

It is also advantageous that the inflow means are designed to generate a gas flow, so that gas flows away from a joining element present in the presentation position. A negative pressure can thus be generated on the joining element with the gas flow, so that a corresponding negative pressure holding force permanently holds the joining element in the template position. The amount and level of the holding force can also be determined via the level of the negative pressure.

According to an advantageous embodiment of the invention, the presentation position is formed along a path that can be covered by the stamp between a retracted position and a position that is extended in the direction of a component section. In this way, the joining element is advantageously carried along by the stamp at the template position.

It is also possible with an arrangement according to the invention, for example via a control unit for controlling the operation of the tool, to reduce or eliminate the pressure difference and thus the holding force at the template position when the punch takes the joining element from the template position in the direction of the component section.

However, it is also possible to permanently increase the pressure difference receive. The stamp can apply a force that is many times greater than the holding force on the joining element for detachment from the template position and can thus detach the joining element and take it with it in the direction of the component section. Advantageously, the stamp does not have to move towards the joining element in a manner coordinated with physical holding means in the vicinity of the held joining element, since with the pressure difference there are no such physical holding means or such can be dispensed with. This avoids a possible risk of collision of the stamp when picking up the joining element held according to the invention by differential pressure.

The invention relates to a tool for attaching a joining element to a component section with a linearly movable punch, with a device according to one of the aforementioned variants being present.

character description

Figur 1

einen Teil eines erfindungsgemäßen Werkzeuges im Schnitt entlang einer Werkzeugachse und

Figur 2

einen vergrößerten Ausschnitt aus Figur 1.

Further features and advantages of the invention are explained in more detail using a schematically illustrated embodiment of a tool according to the invention. In detail shows:

figure 1

a part of a tool according to the invention in section along a tool axis and

figure 2

an enlarged section figure 1 .

The figures show part of a tool according to the invention designed as a riveting tool 1 for processing joining elements, with a joining element designed as a semi-hollow punch rivet 2 being processed by way of example. The semi-hollow punch rivet 2 is held in a holding or presentation position 3 in the riveting tool 1 . The semi-tubular punch rivet tool 1 is used to insert the semi-tubular punch rivet 2 in, for example, two or more material layers (not shown) to be connected to one another, which consist, for example, of a metallic or other material.

For the positioning of the semi-tubular rivet 2 in the template position 3 on the riveting tool 1, the semi-tubular rivet 2 is removed from a storage space for a large number of semi-tubular rivets, which is remote from the actual riveting tool 1, via z. B. a feed hose (not visible) and a feed 6 connected thereto on the tool side with a feed channel 7 for the semi-hollow punch rivets are conveyed in direction P3 into a rivet setting head 4 of the riveting tool 1 . A stamp of the riveting tool 1, which can be moved back and forth linearly via a drive unit of the tool 1 according to the arrows P1 and P2 and is designed as a rivet setting pin 5, takes a single semi-tubular punch rivet 2 from the template position 3 in the direction P4 and presses the semi-tubular punch rivet 2 in a joining process, for example in a laminated core in order to bring the sheets into an at least positively connected state.

The sectional view from the figures 1 and 2 result from a section along the longitudinal axis of the rivet setting pin 5.

When the rivet setting pin 5 is in the extended state in the direction of a die unit (not shown) of the riveting tool 1 , it is surrounded on the outside circumferentially by a hold-down device designed as a hold-down lug 9 . The relevant layers of material such. B. a laminated core lie during the joining process with an underside on a matrix arrangement of the riveting tool 1, with the hold-down nose 9 fixing the laminated core from above or pressing on the stamp side.

The semi-tubular punch rivet 2 is not fed from the store in the axial direction or in the direction of the longitudinal axis L of the semi-tubular punch rivet 2 into the rivet setting head 4, but in the transverse direction to the longitudinal axis L of the semi-tubular punch rivet 2 through the feed 6 the rivet setting pin 5 are fired, with an otherwise necessary mechanism can be dispensed with, for example, a slide mechanism, which rotates the semi-tubular punch rivet 2 by 90 degrees before the stamp the semi-tubular punch rivet 2 in direction P4 according to the in the figures 1 and 2 orientation shown, one bottom of the rivet first.

The semi-hollow punch rivet 2 is conveyed by means of an air flow 8 in the direction of P3 and injected directly under the rivet setting pin 5 or its front or end-side flat face 5a and held there aligned in a presentation position 3 in a fixed position, which the figures 1 and 2 demonstrate. In this case, the semi-tubular punch rivet 2 is held in place by a pressure difference acting on the outside of the semi-tubular punch rivet 2 in accordance with the air flow 8 . So that the semi-tubular self-piercing rivet 2 feels the pressure difference in the template position 3, there is a discharge line for the air, for example on a side of the held semi-tubular self-piercing rivet 2 that is at the rear of the inflowing air flow 8. The semi-tubular self-piercing rivet 2 is thus pushed into the template position 3 and remains there for as long the air flow 8 or a pressure difference exists.

In the present exemplary embodiment, a low-pressure bore 10 is provided, in which there is a negative pressure or low pressure in relation to a reference pressure such as, for example, ambient or atmospheric pressure. When the semi-tubular self-piercing rivet 2 reaches the template position 3 and closes an opening 10a of the low-pressure bore 10, the semi-tubular self-piercing rivet 2 is sucked into the opening 10a due to the negative pressure in the low-pressure bore 10 and remains in the preliminary position 3. With the negative pressure in the low-pressure bore 10 on the one hand and a to higher, for example, an ambient pressure in the remaining area around the semi-tubular punch rivet 2, a pressure difference at the semi-tubular punch rivet 2 becomes effective, which holds the semi-tubular punch rivet 2 in the template position. The negative pressure in the low-pressure bore 10 can be established, for example, by a suction or vacuum arrangement, which air from the Low-pressure bore 10 sucks.

With the invention, an otherwise necessary mechanism or arrangement for mechanically holding the semi-hollow punch rivet 2 in the presentation position 3, such as a slide mechanism, for example, is dispensed with.

So far, it has been disadvantageous that guiding a semi-hollow punch rivet through a rivet setting head and holding it places comparatively high demands on the reliability of the mechanics, taking into account the smallest possible interference contour of the rivet setting head.

The position of the semi-tubular punch rivet 2 in the rivet setting head 4 must always be clear, especially when its direction of movement changes from a transverse direction of movement to below the rivet setting pin 5 to an axial direction of movement in which the rivet setting pin 5 pushes the semi-tubular punch rivet 2 through the hold-down nose 9. If the semi-hollow punch rivet 2 tilts or twists even slightly in the riveting tool 1 or in the rivet setting head 4, this leads in most cases to damage or destruction of components of the rivet setting head 4. This is where the invention comes into play.

According to the invention, the semi-tubular punch rivet 2 is not held under the rivet setting pin 5 by a holding mechanism but by a differential pressure, for example by negative pressure in the low-pressure bore 10 or positive pressure from the side of the feed channel 7 .

The transition from the lateral z. B. horizontal feed of the semi-tubular punch rivet 2 according to P3 in the further movement of the semi-tubular punch rivet 2 by the rivet setting pin 5 takes place in a continuous path without interference contours and / or without component offsets. This ensures continuous, low-wear transport of the semi-tubular punch rivet 2 in the riveting tool 1 .

The semi-hollow punch rivet 2 is in particular by negative pressure or overpressure is conveyed or blown under the rivet setting pin 5, other possibilities being conceivable, for example by gravity.

The holding force on the semi-tubular punch rivet 2 due to the negative pressure p acting in the template position 3 is released as soon as the semi-tubular punch rivet 2 is minimally or slightly pushed out of the template position 3 by the action of the descending rivet setting pin 5 . Holding sections on the rivet setting head 4 that come into contact with the semi-tubular punch rivet 2 then take over the positioning or guiding of the semi-tubular punch rivet 2. The semi-tubular punch rivet 2 is always moved in a defined, aligned manner.

The semi-tubular punch rivet 2 shot into the rivet setting head 4 transversely to the direction of movement P1, P2 of the rivet setting pin 5 according to P3 strikes the contact contour 14 of a stop 11. Opposite the feed channel 7, the stop 11 forms part of a movement channel for the rivet setting pin 5 in the area of the template position 3.

The stop 11 is located immediately below the rivet setting pin 5 in accordance with the figures 1 and 2 fully retracted position towards P2. The shape of the wall 11a of the stop 11 is shell-like with a radius that corresponds approximately to an outer radius of a shank 12 of the semi-tubular punch rivet 2, which is the same for all semi-tubular punch rivets of different lengths that can be processed with the riveting tool. The wall 11a is drilled through and the low-pressure bore 10 formed therewith is subjected to negative pressure. As a result, the semi-tubular punch rivet 2 or its shank 12 is sucked onto the wall 11a and the semi-tubular punch rivet 2 is held in the presentation position 3 . The low-pressure bore 10 runs through the rivet setting head 4 to a suitable location, in particular in an area of the riveting tool 1 that is not critical to interfering contours, at which z. B. a sensor and / or a pressure switch by measuring the low pressure in the low-pressure bore 10 can determine whether there is a semi-tubular punch rivet under the rivet setting pin 5 or Not. A presence check for a held semi-tubular punch rivet 2 is thus provided by low pressure combined with the holding function. A large number, for example, several tens of thousands of semi-tubular punch rivets can be treated in such a way that the semi-tubular punch rivet 2 is reliably sucked in in all spatial positions of the rivet setting head 4 and that the low-pressure bore 10 is not clogged by abrasion.

In addition, an air filter can be provided in the low-pressure bore 10, with which the sensor is kept free of particles z. B. caused by abrasion from the supply hose or the feeder 6 or a coating of the semi-hollow punch rivet 2. In another function, the sensor, for example a pressure sensor, can also check whether the air filter is clogged.

Viewed in direction P3, a rivet head 13 with a fillet 13a is in at least almost form-fitting contact with the correspondingly convex-shaped section of the wall 11a. Along this, the semi-hollow punch rivet 2 can be displaced in the first movement section from the template position 3 by the rivet setting pin 5 in the direction P4 and at the same time somewhat counter to the direction P3 until the longitudinal axis L and the longitudinal axis S of the stamp coincide.

In order to ensure that the semi-tubular self-piercing rivet 2 can be moved forwards by the preceding rivet setting pin 5, the longitudinal axis of the stop 11 is slightly offset in relation to the longitudinal axis S of the punch, so that the incoming semi-tubular self-piercing rivet 2 with the air flow 8 is a little further or over the Center of a hollow punch channel 9a in the hold-down nose 9 flies. The semi-tubular punch rivet 2 is thus moved slightly relative to the front face 5a of the rivet setting pin 5 by the advancing rivet setting pin 5, specifically back in the direction of the feed channel 7. After the rivet head 13 has moved out of its form-fitting position on the wall 11a, he continued through the cylindrical wall of the punch channel 9a in the hold-down nose 9. By advancing the rivet setting pin 5 the semi-hollow punch rivet 2 automatically moves out of its form-fitting position from the presentation position 3 without z. B. a mechanical lever or a snapper must be activated.

With the arrangement according to the invention, the semi-tubular punch rivet 2 is held securely in all spatial positions of the rivet setting head 4, in particular also in an overhead position of the rivet setting head 4.

Reference list:

1

riveting tool

2

Semi-tubular punch rivet

3

submission position

4

rivet setting head

5

rivet setting pin

5a

face

6

feeding

7

feed channel

8th

airflow

9

hold-down nose

9a

stamp channel

10

low pressure bore

10a

opening

11

attack

11a

Wall

12

shaft

13

rivet head

13a

fillet

Claims (5)

1. Tool having a linearly movable punch for attaching a joining element (2), such as a self-piercing rivet, a solid punch rivet or clinch rivet, to a component portion, wherein, using the punch (5), a joining element (2) presented in a presentation position (3) is able to be shifted onto the component portion from the presentation portion (3), wherein the tool comprises means for providing a pressure difference in the region of a presented joining element (2), which comprise blower means for providing a gas stream (8), directed transversely to a vertical direction of movement of the punch (5), in the region of a present joining element (2), wherein the gas stream (8) flows around the joining element (2) such that a retaining force on the joining element (2) is able to be provided, which keeps the joining element (2) in the presentation position (3), wherein a wall portion (11a) of the tool (1), which extends as far as a region that is able to be occupied by a joining element (2) in the presentation position (3), is configured such that a joining element (2) reaching the presentation position (3) takes up the presentation position (3), so as to be oriented in a correct position, under the action of the gas stream (8), characterized in that the wall portion (11a) is configured in such a way, and the means for providing the pressure difference are configured in such a way, that, to realize the retaining force on a joining element (2), wherein the wall portion (11a) is configured so as to match an outer contour of the joining element (2), components or elements that extend movably as far as the presentation position are neither necessary nor present.
2. Tool according to Claim 1, characterized in that discharge portions (10) for conveying away the directed gas stream (8) are present in a region in which a joining element (2) occupies the presentation position (3).
3. Tool according to either of the preceding claims, characterized in that a negative-pressure arrangement for generating a negative gas pressure is present in the region of the presentation position (3).
4. Tool according to one of the preceding claims, characterized in that a positive-pressure arrangement for generating a positive gas pressure is present in the region of the presentation position (3).
5. Tool according to one of the preceding claims, characterized in that the presentation position (3) is formed along a path, able to be covered by the punch (5), between a retracted position and a position extended in the direction of a component portion.

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