BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic sectional view through a joined connection between a component and a bolt-shaped joining element;
FIGS. 2A-2C are diagrammatic, sectional views through the joining element and the component according to FIG. 1 and a template in different stages during a setting operation of the joining element;
FIG. 3 is a diagrammatic, sectional view as in FIG. 2C, with the template according to a first alternative;
FIG. 4 is a diagrammatic, sectional view as in FIG. 2C, with the template according to a second alternative;
FIG. 5A is a diagrammatic, plan view of the joining element having a hexagonal shaft region;
FIG. 5B is a diagrammatic, side view of the joining element having the hexagonal shaft region;
FIG. 6A is a diagrammatic, plan view of a component upper side having a round component hole;
FIG. 6B is a diagrammatic, plan view of the component upper side having a hexagonal component hole;
FIG. 7A is a diagrammatic, perspective view of the joining element having a circular shaft region with individual securing lugs;
FIG. 7B is a diagrammatic, plan view of the template having individual discrete shearing webs; and
FIG. 7C is a diagrammatic, cross-sectional view of the joining element shown in FIG. 7A together with the template according to FIG. 7B, in the inserted state in a component at the end of the setting operation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a joined connection formed of a component 2 having a component hole 4, into which a joining element 6 which is configured as a bolt is inserted and which forms a form-fitting connection with the component 2 both in an axial direction 8 and also in a rotational direction about the axial direction 8. The component 2 and the joining element 6 are preferably composed of stainless steel.
The joining element 6 contains a head region 10 and, in a set state, lies with its head underside on a component upper side 12. The head region 10 is adjoined in the axial direction 8 by a shaft region 14 having a non-round external contour. In the exemplary embodiment, the shaft region 14 has a hexagonal external contour having a total of six corner regions 15 which extend in the axial direction 8. The shaft region 14 is adjoined by a bolt section 16 which has, for example, a thread (not shown here in greater detail). A further component can be fastened to the joining element 6. The joining element 6 is configured as what is known as a press-in bolt.
A plurality of securing lugs 18 are formed circumferentially on the shaft region 14 for axial securing. The securing lugs 18 have a cross-sectional or base surface which is triangular or trapezoidal as viewed in cross section. The securing lugs 18 are formed during production of the joined connection by partial shearing off of shaft material 20 and displacement of the latter against a component lower side 22. Here, in the exemplary embodiment, the securing lugs 18 are pressed into an inner wall of the component hole 4 in order to form an antirotation safeguard, that is to say the securing lugs 18 have deformed the component hole 4 during production of the joined connection in the lower region of the component hole 4. The securing lugs 18 are disposed individually in the circumferential direction and are spaced apart from one another. Here, the spacing is approximately the width of the individual securing lugs 18 on their base side which faces away from the head region 10.
On account of the thickened portion which is caused by the shearing off in comparison with the external diameter d1 of the shaft region 14 in the initial state (see FIG. 2A), a form-fitting connection which acts in the axial direction is also produced at the same time. The component 2 is therefore clamped in fixedly in terms of rotation between the securing lugs 18 and the head region 10. In the exemplary embodiment of FIG. 1, the securing lugs 18 end flushly with the component underside 22.
As a result of the shearing off of the shaft material 20, shearing faces 24 are formed below the securing lugs 18, as viewed in the axial direction 8. As viewed in cross section, the shearing faces 24 lie on a circular line of a circle having a diameter d2 which is smaller than d1 and corresponds to the internal diameter of a hole 28 of a template 26, with the aid of which the securing lugs 18 are formed.
The setting method will be explained in the following text using FIGS. 2A-2C. First, the joining element 6 is inserted into the component hole 4. The component hole has a diameter d3 which is greater than or equal to the external diameter d1 of the shaft region 14. Subsequently, a template 26 is moved against the component 2. The bolt section 16 dips into the cylindrical hole 28 of the template 26. In the exemplary embodiment of FIGS. 2A-2C, the hole 28 has a constant internal diameter d2 which is smaller than the external diameter d1 of the shaft region 14. At the same time, the diameter d2 is greater than an internal diameter d4 of the shaft region 14 (see FIG. 5A). Here, the internal diameter is defined by the minimum spacing of the faces of the shaft region 14 which lie opposite one another. The relationship d4<d2<d1 is therefore valid, the diameters preferably being adapted to one another in such a way that d2−d4<(d1−d4), that is to say the internal diameter d2 of the hole lies closer to the internal diameter d4 than to the external diameter of the shaft region 14.
As a result of these diameter relationships, the corner regions 15 are therefore sheared off partially, the partially sheared off shaft material 20 is pushed by the template 26 in front of itself against the component underside 22 and is also pressed into the component 2 in the exemplary embodiment. Here, the shaft region 14 dips into the hole 28 by a shearing depth. The shearing depth corresponds to the length of the shearing faces 24 in the axial direction. Finally, the template 26 comes into contact with the component underside 22 by way of its front side, and the pressing-in operation is ended. During the pressing-in operation, the head region 10 is held counter to the feed movement of the template 26 with the aid of a non-illustrated supporting device. Subsequently, the template 26 is pulled off from the shaft region 14 and from the bolt section 16 again.
The diameter relationships and the shearing depth are then adapted to one another in such a way that an external diameter d5 which is formed in the set final state by the securing lugs 18 is preferably approximately from 10 to 30% and, in particular, 20% greater than the external diameter d3 of the component hole 4. As a result of this, a reliable axial form-fitting connection is produced which also withstands high pulling-out forces.
In the variant according to FIG. 3, there is provision for the hole 28 of the template 26 to taper conically toward the front, that is to say the hole 28 has its smallest internal diameter in the front shearing region of the template 26, by way of which the shearing is performed. A cavity 30 is therefore formed between the hole inner wall and the shaft region 14 or bolt section 16 outside the shearing region. There is therefore only a very small annular or linear contact area between the template 26 and the shaft region 14, with the result that the friction forces during withdrawal of the template 26 and therefore the pulling-out forces which act on the joining element 6 during withdrawal of the template are as small as possible.
In a further alternative refinement of the template 26 according to FIG. 4, the template 26 has, in the front shearing region, a circumferential shearing ring 32 which protrudes beyond the remaining end face of the template 26. As a result of this measure, the securing lugs 18 are pushed further into the component 2, with the result that the security against rotation and pressing out is increased.
The preferred hexagonal external contour of the shaft region 14 which is configured in the manner of a nut can be gathered again from FIGS. 5A, 5B. Instead of the bolt section 16 of the preceding exemplary embodiments, the joining element according to FIGS. 5A, 5B then contains a sleeve section 34 which adjoins the shaft region 14 and in which an internal thread is preferably formed. In a further alternative refinement, the joining element 6 overall is configured as a press-in nut, in which the shaft region 14 itself is formed as a sleeve having an internal thread.
Two different cross-sectional geometries of the component hole 4 can be gathered from the plan views of the component 2 according to FIGS. 6A, 6B. According to FIG. 6A, the component hole 4 is of circular configuration. This variant is preferably used for components 2 which can be deformed and in which deformation of the component 2 is not critical. In this case, the securing lugs 18 are pressed into the component 2, as shown in FIGS. 1-4, in order to ensure an antirotation safeguard.
In contrast with this, in the exemplary embodiment according to FIG. 6B, the external contour of the component hole 4 is likewise hexagonal, like that of the shaft region, with the result that an antirotation safeguard is already achieved on account of the adapted external contours, without deformation of the component 2 being necessary. Apart from an installation play, the dimensions of the component hole 4 correspond to those of the shaft region 14. FIG. 7A shows the state of the joining element 6 having the securing lugs 18 which are formed after the setting operation. The shaft region 14 is cylindrical in the initial state. The securing lugs 18 have a conical geometry.
In the design variant according to FIGS. 7A-7C, the shaft region 14 is then of circular configuration, as viewed in cross section, and the template 26 has radially inwardly oriented projections which form shearing webs 36, in a deviation from the previously described circular geometry of the hole 28. The shearing webs 36 shear off the shaft material 20 partially during the pressing-in operation of the joining element 6 and form the securing lugs 28.
The method which is described here and the joined connection are suitable, in particular, for component pairings, in which sufficient deformation of the joining element 6 and/or the component 2 in order to produce the form-fitting connection is not possible. In particular, this method is suitable for a joined connection between the joining element 6 which is composed of stainless steel and the component 2 which likewise is composed of stainless steel.
Patent Application
20070253770
