Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
  • F16H55/02—Toothed members; Worms
  • F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D5/00—Power-assisted or power-driven steering
  • B62D5/008—Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D5/00—Power-assisted or power-driven steering
  • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
  • B62D5/0409—Electric motor acting on the steering column
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
  • F16H55/02—Toothed members; Worms
  • F16H55/22—Toothed members; Worms for transmissions with crossing shafts, especially worms, worm-gears
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T74/00—Machine element or mechanism
  • Y10T74/19—Gearing
  • Y10T74/19642—Directly cooperating gears
  • Y10T74/19698—Spiral
  • Y10T74/19828—Worm

Definitions

• the invention relates to a motor-driven power steering system for motor vehicles according to the preamble of claim 1.
• the invention also relates to a power transmission element for such a steering system according to claim 9.
• the overlay transmission known from the generic document is part of a motor-operated power steering system for a motor vehicle, in which the driver's steering movement is assisted by a motor.
• the steering wheel acts on a first transmission input and a servomotor applies a second transmission input of the superposition gearing, which superimposes the rotational angle of the two transmission inputs on the transmission output.
• the steering parts used for the transmission or support of the direct mechanical power flow are made in the generic document and also in the known from practice transmissions mainly of metallic material. This ensures a constant safety of the component over its lifetime. An artificial aging due to environmental influences and the like is low in metallic materials.
• the disadvantage here is the high moment of inertia and the high weight of the components.
• At least one of the two gear members is made of an elastic material, preferably plastic.
• the tooth of a gear member is in this case seen in the direction of the continuous toothing larger than the tooth gap of the other gear member.
• the mutually engaged teeth of the two gear members thus engage elastically braced in one another, so that the usual backlash is repealed.
• slot-like recesses extend in the radial direction into the blank of the toothed wheel.
• Such a transmission is understandably only suitable for the transmission of small powers and is e.g. used in heating flaps or the like.
• the present invention is therefore based on the object, a transmission, in particular a superposition gear for steering systems of motor vehicles to create fen, in which the advantages of a low-cost to manufacture and easy-to-use non-metallic material can be used without a failure of the steering system due to a failure of the non-metallic material must be feared.
• the advantages resulting from the non-metallic material can be combined with the advantages of another material.
• the further material may be designed such that at greater forces, especially in abuse, and in case of failure of the non-metallic material, the power transmission is taken from this. The power flow is thus secured by the other material.
• the non-metallic material is used for power transmission, so that a low mass moment of inertia and a low weight can be realized.
• the non-metallic material is secured by a further material, the Non-metallic material can be produced inexpensively and easily used. A use of an expensive non-metallic material, which is brought in terms of its mechanical properties on the state of a metallic material and thus in particular can not be used in terms of cost, is not necessary.
• the non-metallic material is arranged in the middle region of the circumference of the force transmission element and the outer region adjoining the middle region of the circumference of the force transmission element is formed from a high-strength, durable material.
• non-metallic material is made of plastic.
• the heavy-duty, durable material made of hard, fiber-reinforced plastic and / or a metallic material, preferably steel, is formed.
• Fig. 1 is an illustration of a power transmission element and a gear member engaged therewith;
• Fig. 1 shows a power transmission element 1 of a superposition gear for steering systems, which is in engagement with a gear member 2.
• the power transmission element is formed in the present embodiment as a screw 1 and the gear member as a worm wheel 2.
• the worm 1 has a toothing 3 for transmitting power at its circumference la.
• the worm 1 is formed on the circumference la of two different materials.
• spiel it is a non-metallic material formed from plastic 4 and a heavy-duty, durable material formed from steel 5.
• the plastic 4 is arranged in the middle region of the circumference la of the screw 1 and the steel 5 at the outer regions of the circumference la.
• the power transmission through the arranged in the central region of the circumference la plastic 4. Only with large transmission forces, especially in abuse case and a failure of the central region, the outer area of steel 5 is used and takes over the power transmission. The power transmission is thus protected by the exterior of steel 5.
• plastic 4 various plastics such as e.g. Polyamide, suitable.
• the respective selection of the most suitable plastic can be adapted to the specific situation.
• Conceivable here is also a hard, fiber-reinforced plastic. It is only important that this material can absorb large transmission forces and guarantees a failure of the center area reliable operation of the steering system.
• the screw 1 shown in FIG. 1 essentially comprises a metallic one formed from the steel 5 Base 6, which has a recess 7 in the middle region of the circumference la, in which the non-metallic material 4, in the present case the plastic 4, is injected.
• Such an embodiment of the screw 1 has been found to be particularly suitable with respect to a simple and inexpensive production.
• connection between the steel 5 or the main body 6 and the plastic 4 can take place in a particularly advantageous manner via a mechanical internal toothing 8.
• a mechanical internal toothing 8 By the internal teeth 8, a firm and reliable connection between the steel 5 and the plastic 4 is ensured.
• the screw 1 is first produced as a cylindrical blank with the injected plastic 4 and in the outer region of the circumference la of steel 5 and in the middle region of plastic 4 is. Subsequently, by means of known technology, for example cutting, the toothing 3 can be introduced.
• the toothing 3 is already prepared in the outer area made of steel 5 and this diameter is slightly less than that of the subsequently introduced center area of plastic 4, which is nachant after insertion for generating a toothing 3 and thus leveled ,
• the introduced in the center region of plastic 4 is merely sprayed, that is, in extreme cases, only a kind of coating. If appropriate, various known coating processes can be used for this purpose.
• the shape shown in FIG. 1, in which the plastic 4 extends deeply into the base body 6 or into the worm 1, is advantageous. The advantages already mentioned can thus be achieved particularly well.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Thermal Sciences (AREA)
• Gears, Cams (AREA)
• Gear Transmission (AREA)
• Power Steering Mechanism (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7706807

Family Applications (1)

Country Status (7)

Families Citing this family (4)

Citations (8)

Family Cites Families (8)

• 2001
  • 2001-11-24 DE DE10157639A patent/DE10157639A1/de not_active Withdrawn
• 2002
  • 2002-11-14 JP JP2003547228A patent/JP2005510404A/ja not_active Withdrawn
  • 2002-11-14 EP EP02779560A patent/EP1446316B1/de not_active Expired - Lifetime
  • 2002-11-14 DE DE50202589T patent/DE50202589D1/de not_active Expired - Lifetime
  • 2002-11-14 CN CNA028232976A patent/CN1592695A/zh active Pending
  • 2002-11-14 US US10/496,407 patent/US20050039561A1/en not_active Abandoned
  • 2002-11-14 ES ES02779560T patent/ES2239257T3/es not_active Expired - Lifetime
  • 2002-11-14 WO PCT/EP2002/012761 patent/WO2003045758A1/de not_active Ceased

Patent Citations (8)

Non-Patent Citations (3)

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