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US-12623627-B2 - Modular system for a belt tightener comprising a spur gear mechanism, and belt tightener

US12623627B2US 12623627 B2US12623627 B2US 12623627B2US-12623627-B2

Abstract

A modular system ( 11 ) for a belt tensioner ( 10 ) comprising a spur gearing ( 18 ) comprises plural step wheel pairings of a first step wheel ( 28 ) and a second step wheel ( 30 ), wherein for each of the step wheel pairings the number of teeth of the first step wheel ( 28 ) and the number of teeth of the second step wheel ( 30 ) are different from those of the other step wheel pairings, but the distance between a shaft ( 44 ) of the first step wheel ( 28 ) and the shaft ( 44 ) of the second step wheel is equal for each of the step wheel pairings. In addition, the modular system ( 11 ) comprises identically designed housings ( 20 ) into each of which a spur gearing ( 18 ) with one of the step wheel pairings can be introduced.

Inventors

  • Michael Lohmeier
  • Wolfgang Holbein

Assignees

  • ZF AUTOMOTIVE GERMANY GMBH

Dates

Publication Date
20260512
Application Date
20230817
Priority Date
20220826

Claims (10)

  1. 1 . A modular system for a belt tensioner ( 10 ) comprising a spur gearing ( 18 ), wherein the spur gearing ( 18 ) includes at least one motor gearwheel ( 26 ) and at least a first step wheel ( 28 ) and a second step wheel ( 30 ), the at least one motor gearwheel ( 26 ) forming a first gear stage ( 34 ) with the at least one first step wheel ( 28 ) and the at least one first step wheel ( 28 ) forming a second gear stage ( 36 ) with the at least one second step wheel ( 30 ), wherein the modular system ( 11 ) includes plural step wheel pairings of the at least one first step wheel ( 28 ) and the at least one second step wheel ( 30 ), wherein the modular system ( 11 ) includes identically designed housings ( 20 ) into each of which the spur gearing ( 18 ) with one of the step wheel pairings can be introduced, wherein each at least one first step wheel ( 28 ) and each at least one second step wheel ( 30 ) has an opening ( 42 ) axially passing through the respective step wheel ( 28 , 30 ) for holding a shaft ( 44 ), a bearing point of the housing ( 20 ) being associated with each shaft ( 44 ), and wherein, for each of the step wheel pairings, the number of teeth of the at least one first step wheel ( 28 ) and the number of teeth of the at least one second step wheel ( 30 ) are different from those of the other step wheel pairings, but the distance between the shaft ( 44 ) of the at least one first step wheel ( 28 ) and the shaft ( 44 ) of the at least one second step wheel ( 30 ) is equal for each of the step wheel pairings.
  2. 2 . The modular system according to claim 1 , wherein the sum of the numbers of teeth of the at least one first step wheel ( 28 ) and the at least one second step wheel ( 30 ) in the second gear stage ( 36 ) is equal for each of the step wheel pairings.
  3. 3 . The modular system according to claim 1 , wherein each gearwheel ( 26 , 28 , 30 , 32 ) inserted in the belt tensioner ( 10 ) has an opening ( 42 ) axially passing through the respective gearwheel ( 26 , 28 , 30 , 32 ) for holding a shaft ( 44 ) and a bearing point of the housing ( 20 ) is associated with each shaft ( 44 ), and wherein each distance between two of the shafts ( 44 ) at a time is equal for each of the step wheel pairings.
  4. 4 . The modular system according to claim 1 , wherein the first gear stage ( 34 ) is arranged to be closer to a lower side ( 22 ) of the housing ( 20 ) than the second gear stage ( 36 ).
  5. 5 . The modular system according to claim 1 , wherein the size of the identically designed housings ( 20 ) is adapted to hold the step wheel pairing with the highest space requirement.
  6. 6 . The modular system according to claim 1 , wherein at least two meshing gearwheels ( 26 , 28 , 30 , 32 ) of the spur gearing ( 18 ) have a helical gear, specifically the at least one first step wheel ( 28 ) and the at least one second step wheel ( 30 ).
  7. 7 . The modular system according to claim 1 , wherein each of the step wheel pairings includes a visual identifier ( 50 ).
  8. 8 . The modular system according to claim 1 , wherein the modular system ( 11 ) comprises plural electric motors ( 40 ) which can be operated at different voltages, and/or an electric motor ( 40 ) which can be operated at least at two different voltages, the electric motor ( 40 ) in the belt tensioner being connected to the motor gearwheel ( 26 ) for driving the motor gearwheel ( 26 ).
  9. 9 . The modular system according to claim 1 , wherein the step wheels ( 28 , 30 ) of the step wheel pairings are manufactured using an injection molding process and/or using a sintering process.
  10. 10 . A belt tensioner which is manufactured by the modular system ( 11 ) according to claim 1 .

Description

RELATED APPLICATIONS This application is a U.S. National Stage Application filed under 35 USC 371, claiming priority to Serial No. PCT/EP2023/072672, filed on 17 Aug. 2023; which claims priority from DE Patent Application 10 2022 121 643.8, filed 26 Aug. 2022, the entireties of which are hereby incorporated herein by reference. TECHNICAL FIELD The invention relates to a modular system for a belt tensioner, particularly for a belt tensioner for a seatbelt system, comprising a spur gearing, and to a belt tensioner that is manufactured by such modular system. BACKGROUND A belt tensioner is used, in a case of restraint, to reduce certain influences which have a negative effect on restraining a vehicle occupant, before the forward movement of the vehicle occupant begins to move forward and, wherein necessary, a load-limiter starts to be used. Said influences include, for example, the so-called film reel effect and the belt slack. The film reel effect is webbing wound loosely onto a belt reel. In the case of the belt slack, the webbing is only loosely adjacent to the vehicle occupant. The belt tensioner reduces the belt slack and the film reel effect within a split second by winding the webbing onto a belt reel of a belt retractor, for example, and thus tensioning the webbing. Consequently, the vehicle occupant can participate in the vehicle deceleration at an early stage. Moreover, the conditions for the subsequent use of a load-limiter are improved. Belt tensioners in which, when triggered, a pyrotechnic set is ignited which drives a retracting mechanism are known already. Those belt tensioners can be triggered only once and are designed for the load case of full tensioning, viz. for the event that the vehicle occupant is to be fixed as quickly as possible and with a high degree of force. Also, belt tensioners are known which are driven using an electric motor, particularly so-called reversible belt tensioners. In this context, “reversible” means that the belt reel can be driven in both directions, on the one hand, to tension the webbing, and, on the other hand, to reverse the tensioning again. For tensioning, the electric motor must provide a high torque at a high speed so that the belt can be tensioned with sufficient force and velocity. It is a particular advantage of the use of electric motors as drive means in belt tensioners that it is possible to operate the belt tensioner many times. However, those belt tensioners driven by electric motors are usually optimized and designed for the load case of full tensioning. For example, the electric motor is driven by the 12V power supply of a vehicle in which use is made of the belt tensioner with a maximum feed current in the range from 20 to 40 A. The transmission ratio of the gear transmission of such a belt tensioner is usually within a narrow range from 30 to 35. In these general conditions, tensioning forces ranging from about 100 to 300 N can be achieved within a period of time from about 100 to 150 ms and act upon the shoulder of the vehicle occupant. Belt tensioners of this type designed for the full tensioning cannot be readily used or easily adapted for different alternative or additional use scenarios. This is desirable, however, to enable further functions of the seatbelt system, for example a warning function generated by means of the webbing or a re-positioning of the vehicle occupant. These different applications usually require deviating transmission ratios, however, which have to be made and implemented in a complicated manner via separate gear transmission and housing developments. SUMMARY It is the object of the invention to provide an option that allows to manufacture belt tensioners which can be easily adapted to different use scenarios in a way conserving the resources. The object is achieved by a modular system for a belt tensioner comprising a spur gearing, the spur gearing including at least one motor gearwheel and at least a first step wheel and a second step wheel, the motor gearwheel forming a first gear stage with the first step wheel and the first step wheel forming a second gear stage with the second step wheel. The modular system comprises plural step wheel pairings of the first step wheel and the second step wheel. The modular system further comprises identically designed housings into each of which a spur gearing including one of the step wheel pairings can be introduced. Each first step wheel and each second step wheel have an opening axially passing through the respective step wheel for holding a shaft, wherein a bearing point of the housing is associated with each shaft. For each of the step wheel pairings, the number of teeth of the first step wheel and the number of teeth of the second step wheel are different from those of the other step wheel pairings, but the distance between the shaft of the first step wheel and the shaft of the second step wheel is equal for each of the step wheel pairings. The invention is based on the