SU932974A3 - Servo steering system for trucks - Google Patents

Abstract

The servo assisted steering system is used in motor vehicles, and has a piston which slides in the steering housing. The steering nut is held in the piston and the nut is connected to the steering spindle. The control valve rotating slider in connected to the nut. The spring connecting nut and piston moves the slider of this valve into mid position. The tubular spring (76) is connected to the steering nut and piston so that only torsional moments are transmitted. The tubular spring is made as a cage with longitudinal windows (80) and it may be constructed using end rings connected with longitudinal bars.

Description

(54) SERVER DRIVE STEERING

one

The invention relates to the automotive industry, in particular to servo steering for trucks.

Known servo controls are servo-driven, in which both the steering nut and the working piston are provided with thrust projections of the same width. Corresponding to each other, the thrust surfaces on both control elements are at the middle control position in the same plane. In this case, each thrust surface is loaded with a spring 1.

 The disadvantage of this device is 15 liters, that the spring elements relative to the steering nut supports are located axially at a distance and, when the spring element is activated, a pair of opposing forces is created that act on the steering nut 20. This pair on the steering nut support causes an undesirable multiple increase in friction force. In addition, when using a pre-25 FOR CARGO CARS

loaded spring patterns and with continued driving from the middle position, the steering sensitivity becomes worse, and the loads on the steering nut are asymmetrical.

It is also known to have a servo-controlled steering for trucks, which has a movable piston with a steering nut, which is movably mounted in the steering case, which is kinematically CBS with a steering shaft, and has a rotary valve connected to the steering nut, and a tubular spring, which is installed in the steering case. with the possibility of returning the spool and the middle position of the distributor and one end connected to the steering nut and the other to the piston L2j.

Claims (2)

A disadvantage of the known device is that the spring epameng has to transmit a large axial force, namely all the force acting on the steering nut. At the same time, the steering nut is not located in the piston, so that all the force actions are B1x, when the spring element is attached. Considering that the above mentioned tubular springs must transmit large axial force effects, this can only be carried out by a tubular spring that is rigid to torsion, and the initial control sensitivity does not correspond to the time requirements. The aim of the invention is to increase the hours (the response urgency. The goal is achieved by the fact that the tubular spring is located in the space between the steering and the piston nut and is connected to the Mutut nut by means of a cam connection with the possibility of Fig. 1 shows a steering with a servo drive, a longitudinal section, and Fig. 2 shows a spring-like element, a longitudinal section (the first example of the design is HHH). J in Fig. 3 is the same, cross-sectional cut; in Fig. 4 the same, longitudinal section (second embodiment) jaa of Fig. 5, section A-A in Fig. 4; in Fig. 6 a spring element, (longitudinal section (third embodiment); FIG. 7B-B in FIG. 6. FIG. 1 shows a servo-assisted steering for trucks, containing a movable piston 2 with steering nut 3 installed in the steering case 1 that is mounted in the steering case 1. The nut 3 is kinematically connected to the steering shaft 4. Also, the distributor is installed in the steering. with rotary valve 6, connected to nut 3 steering 1, and a tubular spring 7, installed with the possibility of returning spool 6 to the middle position of the distributor 5 and connected at one end with nut 3 Nya Ullevi control 1 and 2. The tubular piston drugims spring 7 is installed in the space mezhru steering nut 3 and the piston 2 and connected with said nut by a compound cam to move in a radial and axial direction. The tubular spring 7 is rigidly mounted in the piston 2. The tubular spring operates as a torsion bar (Fig. 2-7). In the first example, the tubular spring 7 (Figs. 2 and 3) is designed to achieve a soft torsional spring constant and a corresponding working torsion zone, which is made in the vice bone pipe 8 from spring steel and is provided with elongated holes 9 on the surface. The remaining portions of the surface can be viewed and calculated as being clamped along both ends and flexurally loaded rods 10. In FIG. 2, the upper end of the pipe 8 is provided with a groove 11, into which the cam of the nut 3 of the steering system enters (not a clamp). The lower part of the tubular spring 7 is connected to porische 2, which transmits only torque. In this case, this connection is solved in such a way that the bottom surface 12 of the spring 7 is rigidly mounted in the jack of the piston 2, thereby the tubular spring 7 is not subject to axial forces. There is a gap of about 0.8 mm between the tubular spring 7 and the nut 3 of the steering shaft. FIG. 4 and 5 depict such a pipe-, chat spring 7, which can also be made of a thin-walled steel pipe 8. It is provided with a through slot 13, at the same time, a solution. The connection with the nut 3 of the control 1 is also bare. blows through the groove 11. But the spring in its - Lower part is provided with opposite openings 14, in which the piston pin bushing (not shown). The spring can be made flexible of spring steel sheet. . Shown in FIG. 6 and 7 of the tubular spring 7 is basically the same (Fig. 2 and. 3) in that it concerns the connection of the steering nut 1 and the piston 2. The only deviation from this decision is that the spring is not complete in detail. . In the illustrated form of execution, the torsion spring 7 here has connecting rings 15 and 16 at the top and bottom. The ends of the elastic rods are rigidly fixed to them. Elastic rods 17 are made in this way (spring steel pipes with a cross section of 3 mm. In this case, the groove 11 is made in the upper ring 15, and the surface 12 is made as the outer surface of the lower ring 16. By means of the upper 18 and lower 19 sealing rings of the piston 2, the space 20 is sealed from the upper working space 21 and from the lower working space 22 (Fig. 1). Space 2O through the steering case 1, exhaust port 23 is connected to the working fluid capacity (not shown), whereas the inlet hole Pierce 24 is connected to the pumping pump pipe. (not shown). In this case, oil is used as the working fluid, the direction of sweat (indicated by the arrow 25. Dispenser 5 has a cleanly made kayalsh system, which in the middle position The bodies 5 allow free flow of oil into the spaces 21, iiid, and 20. But when turning the spool 6, the channel system guides the oil into the working spaces 21 and 22, whereby the piston 2 moves forward or backward in the usual way. . Steering servo works as follows. Through the inlet 24, the inner hole 26 of the steering shaft 4 and the pipeline 27, the oil is directed to the steering shaft 4, and through pipes 27 to the spool 6. At the middle position of the distributor 5, the oil passes through the channels and control slots freely into the working fluid container i.e. the position of the piston 2 remains unchanged. When the steering wheel moves, if a torque acts through the steering shaft 4 on the left-hand drive nut 3, and according to the amount of torque of the nut 3 of the steering control 1, the spool 6 of the distributor 5 is also rotated due to the fact that they are connected in practical connection. Movement to stop. The control nut size 3 depends essentially on the characteristics of the tubular spring 7. The same characteristic also determines when the steering moment ceases to tend to the opposite position. When turning the spool 6. In one direction, the distributor 5 guides the oil to the upper working space 2 when the steering shaft in the opposite direction — in the working space 22j, the oil freely enters space 20, from where it is above topography. In this way again it flows into the tank for the working fluid. Under the tubular spring should be understood here all those spring elements that have a contour of a cylindrical surface. During the experiments, it was found that C) and the angle of rotation of the steering shaft in 1-2 in the corresponding working space, an increment of pressure of 0.1 atm without axial movement of the piston should be measured. Continuing ovizhennen piston should be only when the increment aable and over 0.2 atm. Taking into account the fact that the pressure increment in the co-operative working space proceeded progressively and proportionally to the external resistance using the springs according to the soft characteristics, it was possible to approach this progressive curve. Thanks to the steering shaft, the steering gear is easy to maintain, due to which, in turn, the operating sensitivity is significantly improved and the joints feel good. The resistance of the truck's steering wheel. Claims The servo-controlled steering for trucks, comprising a movable piston built into the steering crankcase with a movable steering steering nut kinematically connected to the steering shaft, a rotary distributor; a spool connected to the steering nut and a tubular spring installed with the possibility of returning the spool to the middle position of the distributor and connected at one end to the steering nut and the other to the piston, which is that, in order to increase the sensitivity of the spring, the tubular spring is located in the space between the nut of the ore control and the piston and is connected to the said nut by means of a cam connection with the possibility of movement in the radial and axial direction x, wherein zhestkousganoVlena tube spring in the piston. Sources of information taken into account during the examination 1. Hungary Patent N 148872, cl. In 62 D 5/06, 1974. 2. The patent of Germany N 2414399, cl. In 62 D 5/06, 1976 (prototype). FIG. if FIG. five 12 sixteen fus.6 FIG. 7