Screw and thin metal sheet connection produced therewith
A screw ( 10 ) and a connection produced therewith of a thin metal sheet forming a substructure ( 40 ) to a plastics component ( 30 ) having a through-bore ( 32 ) and having a seal ( 50 ) located between the substructure ( 40 ) and the component ( 30 ). The screw ( 10 ) has a shank ( 13 ) having a thread-cutting thread ( 16 ) and a tip ( 12 ) in the form of a boring part, and also a lower thread section ( 18 ) having a first thread outside diameter (D 18 ) and an upper thread section ( 19 ) having a second, larger thread outside diameter (D 19 ) and having a conically narrowing transition section ( 22 ) between the two thread sections ( 18, 19 ). The upper thread section ( 19 ) has a thread pitch (P 2 ) which is smaller than the thread pitch (P 1 ) of the lower thread section ( 18 ). During the production of the connection, the upper thread is screwed into the through-bore ( 32 ), wherein a form-fit is produced in the component ( 30 ) between the latter and the screw ( 10 ) and the material of the component ( 30 ) rests in a sealing manner around the upper thread section ( 19 ). This produces a combination of a seal without a sealing washer and with a defined distance between the component and the substructure by defined compression of the seal ( 50 ).
1. A connection of a substructure ( 40 ) by a screw to a plastic component ( 30 ) having a through-bore ( 32 , 32 ′) and having a seal ( 50 , 50 ′) located between the substructure ( 40 ) and the component ( 30 ), the connection comprising a screw ( 10 , 10 ′, 10 ″) having a shank ( 13 ) with a thread-cutting or self-tapping thread ( 16 ) and with a tip ( 12 , 12 ′), the substructure is formed from a thin metal sheet, in that the plastic component is produced from a plastic material, the tip ( 12 , 12 ′) is configured as at least one of a boring part or a penetration tip, a lower thread section ( 18 , 18 ′) of the thread adjacent to the tip ( 12 , 12 ′ has a first thread outside diameter (D 18 ), an upper thread section ( 19 , 19 ′) of the thread opposite the tip ( 12 , 12 ′) has a second, larger thread outside diameter (D 19 ), and a transition section ( 22 , 22 ′, 22 ″) with a continuously changing diameter is located between the two thread sections ( 18 , 19 ; 18 ′, 19 ′), wherein the upper thread section ( 19 , 19 ′) has a thread pitch (P 2 ) which is smaller than the thread pitch (P 1 ) of the lower thread section ( 18 , 18 ′), and the connection is produced by a combination of sealing by defined compression of the seal ( 50 , 60 ) and sealing by a form fit between the upper thread section ( 19 , 19 ′, 19 ″) of the screw ( 10 , 10 ′, 10 ″) and the component ( 30 ) and compaction of the material of the component ( 30 ) around the upper thread section ( 19 , 19 ′, 19 ″).
2. The connection as claimed in claim 1 , wherein the compression of the seal ( 50 , 50 ′) corresponds to a difference between the thread pitches of the two thread sections ( 18 , 19 ; 18 ′, 19 ′) multiplied by a number of thread turns of the thread of the upper thread section ( 19 , 19 ′).
3. The connection as claimed in claim 1 , wherein the seal ( 50 , 50 ′) is compressed by between 20% and 80%.
4. The connection as claimed in claim 1 , wherein a diameter (D B ) of the through-bore ( 32 ) in the component ( 30 ) corresponds at least to a core diameter (D GK , D GaK ) of the thread of the lower thread section ( 18 , 18 ′, 18 ″) or of the upper thread section ( 19 , 19 ′, 19 ″) of the screw ( 10 , 10 ′, 10 ″).
5. The connection as claimed in claim 1 , wherein the thread outside diameter (D 19 ) of the upper thread section ( 19 , 19 ′) is coordinated with material properties of the component ( 30 ) by way of the thread outside diameter (D 18 ) of the lower thread section ( 18 , 18 ′, 18 ″).
6. The connection as claimed in claim 1 , wherein a thread form of the upper thread section ( 19 , 19 ′) is coordinated with material properties of the component ( 30 ).
7. The connection as claimed in claim 1 , wherein the component ( 30 ) is a glass fiber reinforced plastic part.
8. The connection as claimed in claim 1 , wherein the seal ( 50 , 50 ′) is attached to the component ( 30 ) on a bearing surface with respect to the substructure ( 40 ) and around the through-bore ( 32 , 32 ′).
9. The connection as claimed in claim 1 , wherein the seal ( 50 , 50 ′) is connected in a sealing manner to the component ( 30 ) on one side and to the substructure ( 40 ) on the other side.
10. The connection as claimed in claim 1 , wherein the connection is used on an outer shell of a building.
11. The connection as claimed in claim 1 , wherein the connection is used on a roof of a building.
12. The connection as claimed in claim 1 , wherein a core diameter (D GaK ), the through-bore ( 32 ) in a region of the upper thread section ( 19 ), and a thread form of the upper thread section ( 19 ) are designed such that a volume (V.sub.GS) displaced by the thread of the upper thread section ( 19 ) is pushed into, and thus seals off, a region of a volume (V aK ) between the core diameter (D GaK ) of the upper thread section ( 19 ) and the through-bore ( 32 ).
13. The connection as claimed in claim 1 , wherein the transition section ( 22 ′) is configured with a thread start of the upper thread section ( 19 ′).
14. The connection as claimed in claim 1 , wherein the transition section ( 22 ) is configured without a thread.
15. The connection as claimed in claim 1 , wherein a part of the shank ( 13 ) that adjoins the transition section ( 22 , 22 ″) in a direction of the tip ( 12 ) is configured as a shank section ( 24 , 24 ″) without a thread.
16. The connection as claimed in claim 1 , wherein a thread pitch (P 1 ) of the lower thread section ( 18 , 18 ′) is in a ratio of 1.1 to 1.5 to a thread pitch (P 2 ) of the upper thread section ( 19 , 19 ′).
17. The connection as claimed in claim 1 , wherein elements ( 34 ) for widening a core hole ( 33 ) bored with the tip ( 12 ) or for heating a material surrounding the core hole ( 33 ) are provided in the transition section ( 22 ″).
18. The connection as claimed in claim 1 , wherein the shank ( 13 ) is provided with a head or a tool engagement portion ( 26 ) at an end opposite the tip ( 12 ).
19. The connection as claimed in claim 18 , wherein the head is configured with a flat disk ( 27 ).
20. The connection as claimed in claim 1 , wherein the thread of the lower thread section ( 18 ) is a sheet-metal screw thread.
21. The connection as claimed in claim 1 , wherein the thread outside diameters (D 19 , D 18 ) of the upper and lower thread sections ( 19 , 18 ) are in a ratio of 1.2 to 1.4.
22. The connection as claimed in claim 1 , wherein the thread sections ( 19 , 18 ) have core diameters (D GaK , D GK ) which are in a ratio of 1.6 to 1.8.
23. The connection as claimed in claim 1 , wherein the transition section ( 22 , 22 ′, 22 ″) is a conically narrowing shank section.
24. The connection as claimed in claim 1 , wherein transition section ( 22 , 22 ′, 22 ″) is formed by a chamfer on a cylindrical part, facing the tip ( 12 , 12 ′), of the upper thread section ( 19 , 19 ′).