DE3724948C2 - - Google Patents

Description

The invention relates to a rack and pinion gear, in particular a tooth rod steering gear for vehicles, according to the preamble of claim 1.

Particularly in the case of rack and pinion steering gears in motor vehicles the track rods articulated off-center on the rack on the rack, the noise and stiffness in the steering gear can cause.

According to FR-PS 11 35 909 rack and pinion steering gear for motor vehicles are known at those to avoid the transmission of torque to the rack a middle part of the tie rods can be moved longitudinally in the housing of the tooth rod is stored. The middle section is protruding radially Support connected to the rack of the steering gear. The verb manure is made via a sleeve-shaped rubber bearing. This steering However, gearbox requires a relatively large amount of space and Manufacturing effort.

The object of the invention is a rack and pinion gear of the genus moderate way to create, in which the output rods with simple means and without rack weakening ball joints on the rack are articulated, in the case of a rack and pinion steering gear favorable steering kinematics is possible.

This object is achieved with the characterizing features of claim 1 solved. An advantageous development of Invention can be found in claim 2.

The drive rods are through the sleeve-shaped rider or tie rods pivotable about the central rack axis on the Rack articulated so that despite their off-center attack Actual torque support through the central rack axis ver running. Disturbing torques are therefore excluded. It is necessary that the Drive rods with the receiving part over a single Joints having a rotational axis are connected. As the rider's pivot bearing on the rack can be a plain bearing or a roller bearing, preferably a Combined axial and radial bearings can be used.

An embodiment of the invention is as follows described in more detail. The schematic drawing shows in  

Fig. 1 a rack and pinion steering gear for motor vehicles with track and in

Fig. 2, the connection rack, rider and tie rod as a single unit II of FIG. 1st

Fig. 1 shows schematically a rack and pinion steering gear ( 10 ) with a rack ( 14 ) slidably mounted in a housing ( 12 ) and a drive pinion ( 16 ). The drive pinion ( 16 ) is connected via a steering spindle ( 18 ) to a steering wheel of the motor vehicle, not shown. The rack and pinion steering gear ( 10 ) is of a known type and is therefore not described in detail.

A rider ( 20 ) is rotatably mounted on the rack ( 14 ). The rider ( 20 ) is articulated with two tie rods ( 22 , 24 ). The tie rods ( 22 , 24 ) interact with steering levers ( 26 , 28 ) of a wheel suspension of the motor vehicle, not shown, for steering the wheels ( 29 , 31 ). The tab ( 20 ) can be arranged differently from the illustration in Fig. 1 at one end of the rack ( 14 ). The rider can also be mounted inside or outside of the housing ( 12 ) on the rack ( 14 ).

The rider ( 20 ) (see. Fig. 2) is composed essentially of a sleeve ( 30 ) and a rotationally symmetrical pin ( 32 ) on which a receiving part ( 34 ) sits. The bushing ( 30 ) can be rotated about roller bearings ( 36 , 38 ) on the rack ( 14 ) about its central axis ( 15 ), but is axially immovable. The rolling bearings are formed immediately by bar on the rack ( 14 ) and the bush ( 30 ) balls; However, axially secured Kugella ger or axial and radial needle bearings or a plain bearing can be used.

The spigot ( 32 ) formed on the bush ( 30 ) extends transversely to the central rack axis ( 15 ) and, via a rubber bearing ( 40 ), can be rotated with limited elasticity, but is held axially immovably by a screw nut ( 42 ) and washer ( 44 ), the receiving part ( 34 ). The tie rods ( 22 , 24 ) are articulated on the receiving part ( 34 ) via rubber bearings ( 46 , 48 ). For this purpose, ring-shaped rubber blocks (silent blocks), which are penetrated by metallic sleeves ( 54 , 56 ), are pressed into the bearing eyes ( 50 , 52 ) of the receiving part ( 34 ). The sleeves ( 54 , 56 ) are screwed to the tie rods ( 22 , 24 ) by screws ( 58 ). This results in a cardanic connection with hinge axes that run transversely to the central axis ( 15 ) of the rack ( 14 ) and transversely to the central axis ( 35 ) of the pin ( 32 ).

A slot ( 60 ) is formed in the housing ( 12 ) of the rack and pinion steering gear ( 10 ), through which the pin ( 32 ) extends out of the housing ( 12 ). The slot ( 60 ) is sealed in a manner not shown by a bellows.

From the tie rods ( 22 , 24 ) emanating interference or reaction forces from the steering forces can exert no disturbing torque on the rack ( 14 ) despite the eccentric articulation of the tie rods (center points 65 ). Rather, the moments in the imaginary extension of the tie rod longitudinal axis become effective in the rack central axis ( 15 ). In this way, the rotating poles ( 62 ) define the effective track lengths even when the wheels of the motor vehicle are deflected in the same direction; the rider ( 20 ) rotates according to the win kelversatz the tie rods ( 22 , 24 ) around the rack ( 14 ). When the wheels reciprocate (e.g. curling in curves), the receiving part ( 34 ) is rotated around the pin ( 32 ) according to the opposite angular offset of the tie rods ( 22 , 24 ), with the turnstile ( 64 ) of the tie rods now With the central axis ( 35 ) of the pin ( 32 ).

In addition, the axes (center points 65 ) of the tie rods form the pivot poles of the tie rods when steering. It can be clearly seen that the different turning poles ( 62 , 64 , 65 ) of the tie rods make it possible to achieve favorable steering-kinematic properties in the interaction of the steering gear and wheel suspension. For example, in a wheel suspension with McPherson strut assembly and relatively high steering levers ( 26 , 28 ), long tie rods are advantageous to avoid self-steering movements with the same sensible spring deflection (rotating poles 62 !). With mutual deflection (tendency to curl in curves), targeted self-steering may be desirable, which can be achieved by using shorter, effective track rod lengths (rotating poles 64 ). Even shorter tie rods can be displayed to achieve a defined steering behavior according to Ackermann (wheel lock angle differences between the inside and outside wheel) (pivot poles 65 ). Furthermore, the pin ( 32 ) relative to the rack ( 14 ) can be placed higher or lower, which also allows a influencing of the tie rod position. It is clearly evident that these different pivot poles can be moved to a limited extent by constructive changes and thus the steering kinematics and the wheel guidance of the motor vehicle can be influenced in a favorable manner.

Claims (2)

1. Rack and pinion gear, especially rack and pinion steering gear for vehicles, in which a sleeve-shaped rider is pivotally mounted on the rack about the longitudinal axis of the rack, which has an arm projecting approximately perpendicular to its pivot axis, to which a drive linkage is articulated, characterized thereby that the sleeve-shaped rider ( 20 ) is mounted on a slide or roller bearing ( 36, 38 ) on the rack ( 14 ), that the projecting arm is formed by a cylindrical pin ( 32 ) and that on the pin ( 32 ) Receiving part ( 34 ) is pivotally mounted, on which on both sides of the journal central axis ( 35 ) two output rods are each articulated via a rubber bearing ( 46, 48 ) with a pivot axis which is approximately perpendicular to the central longitudinal axis of the rack and the central journal containing level runs ver. 2. Rack and pinion gear according to claim 1, characterized in that the receiving part ( 34 ) on the pin ( 32 ) is mounted on a rubber bearing.