DE102013007253B3 - Torsion spring rod system for wheel suspension of two-lane motor vehicle, has torsion spring rod that comprises two rod portions and intermediate spiral or helical spring element, which are arranged between actuator and driven lever - Google Patents

Abstract

The system comprises an actuator (31) that is arranged on a vehicle chassis (20) and is connected to an output lever (38) through a torsion spring rod (22). The biasing force of the output lever acts on a wheel suspension element (12) of a wheel suspension. The torsion spring rod comprising two rod portions (23,25) and an intermediate spiral or helical spring element (26), which are arranged between the actuator and the output lever. The spring element in which the rod portions are rotatably mounted, is supported between two bearing points (35,39).

Description

The present invention relates to a torsion spring rod system for a wheel suspension of a motor vehicle according to the preamble of patent claim 1.

Such a suspension arrangement is exemplified in the DE 10 2009 005 899 A1 known. The suspension arrangement has an actuatable by means of an actuator torsion spring rod which extends in the vehicle transverse direction to approximately in the vehicle transverse center and the wheel side acts on a drive lever, which in turn is articulated to a Radführungselement the suspension. In the DE 10 2009 005 899 A1 the torsion bar is made in several parts and in nested arrangement, in which two radially outer hollow rods and a radially inner solid rod made of spring steel are provided, which are connected to each other via, for example, splines to transmit power.

In the from the DE 10 2009 005 899 A1 known torsion spring rod system, the spring work is absorbed or released in the interplay of the rebound and rebound movement of the wheel. At the same time, it is possible to superimpose moments by means of the actuator, that is to raise or to relax the torsion-spring bars as required. Due to the presence of the suspension spring as a main spring only proportionate restoring forces must be made to Radlaständerung with the turntable. There is always a superposition of the spring forces of main spring and torsion bar instead, depending on how the driving situation requires it and the control pretends. At the output of the torsion bar system is a rocker (output lever), at the end of a coupling is articulated. The coupling connects the rocker with the trapezoidal link, which is connected to the vehicle wheel. Thus, the torques generated in the turntable can be transmitted via the load path motor / gearbox / torsion bar / rocker / coupling / trapezoidal link / vehicle ultimately as linear actuating forces on the vehicle.

In the torsion spring rod system set forth above, the torsion spring bar is composed of a Bourdon tube and a full bar spring. If, for example, there now exists a need to realize a softer torsion spring bar, the diameter of the Bourdon tube and / or the full-bar spring would have to be reduced as a first measure. With the reduction of the diameter, however, the working capacity of the torsion spring rod would decrease and at the same time the stresses would increase disproportionately, so that the tube and bar spring would have to be extended. However, such a change in length is not feasible due to the extremely critical space in the wheel suspension. This has the consequence that, especially for smaller vehicle series, in which a reduction in the total spring stiffness is inevitable, such a turntable can not be installed due to the high packing density.

The object of the invention is to provide a torsion bar system in which structurally and structurally simple means, the spring rate of the torsion spring bar is additionally influenced.

The solution to this problem is stated in the features of claim 1. Advantageous and particularly expedient embodiments of the invention include the subclaims.

According to the characterizing part of claim 1, the torsion spring bar is no longer made of a radially outer tube spring and a radially inner full bar spring, which are nested in order to achieve a maximum spring length with reduced space, but is the torsion spring rod rather between the actuator and the Output lever (that is, the swing arm acting on the wheel guide element) with a first part of the rod and a second part of the rod and with an intermediate coil spring element. With regard to a comfort-related reduction of the spring rate of the torsion bar system, the coil spring element is designed so that at a torsional stress, a widening of the coil spring element takes place radially outward. Such a comparatively small circumferential widening of the helical spring element is not critical with regard to the extremely tight space, so that preference can be given to a design of the sub-rods with a correspondingly large torsion length. Overall, therefore, the longitudinal extension of the torsion bar system is greatly reduced in space-saving manner.

In a space-saving arrangement of the operatively connected to the actuator first partial rod, the coil spring element, and the output lever bearing second partial rod to each other coaxially and in series can be arranged one behind the other. Compared to the partial rod cross-section, the coil spring element may have a substantially larger cross section in order to reduce the spring rate of the torsion bar system sufficiently.

For a stable pivot bearing of the torsion spring rod, it is advantageous if specifically the coil spring element is supported between two body-side pivot bearing points, in which in particular both the first part of the rod and the second part rod are rotatably mounted.

The helical spring element may have at least one, preferably a plurality of helixes guided helically around a helical spring element longitudinal axis, which, viewed in the axial direction, transition into opposite sides into the spring limbs.

Depending on the installation space situation, the spring legs of the helical spring element can protrude outward in the axial direction. Optionally, the spring legs can be offset by a transverse offset to the above-defined coil spring element longitudinal axis or extend coaxially to this longitudinal axis. With regard to a perfect force transmission between the partial bars and the coil spring element, however, it is preferred if the spring legs are offset by a, acting as a lever arm transverse offset of the longitudinal axis.

In a further embodiment, the spring leg can protrude inwardly in the radial direction and, if appropriate, be arranged at right angles to the respectively assigned partial rod.

For a component reduction, it is preferred if the first and the second part rods and the coil spring element and optionally also the output lever are formed of the same material and / or in one piece. The partial rods and the helical spring element may in this case preferably be made of a solid material.

Alternatively, the first and second part rods and the coil spring element may be kept as individual parts, which are joined together at coupling points, in particular detachably.

For this purpose, a coupling part can be connected between at least one of the partial rods and a spring leg of the helical spring element. For a component change, it is preferred if at least the helical spring element is easy to replace in terms of assembly technology. Therefore, the coupling part can have at least one mounting hole in which the spring leg of the coil spring element can be inserted and, if necessary, can be braced by means of a screw connection.

By way of example, the mounting hole of the coupling member may be aligned in the assembly position in the axial direction. In a disassembly case can therefore be reduced by an axial compression of the coil spring element whose longitudinal extent, whereby the spring leg from the axially aligned mounting hole of the coupling member can be brought out.

Alternatively, the mounting hole of the coupling member may also be arranged at right angles to the axial direction. In this case, the spring leg is to be pressed in the radial direction to the outside to lead out the spring leg from the mounting hole.

Mounting technology preferably, the coupling part can be made in two parts with a first clamping body and a second clamping body, between which the spring leg of the coil spring element, for example by a screw, can be clamped. In a further development, the first clamping body can have a connecting contour, for example a connecting pin, which can be connected to the end face of a partial rod. On the other hand, the second clamping body can project at least partially into a cylindrical cavity defined by the helical spring element turns. The coil spring element windings are oriented approximately transversely to the axial direction.

In a particularly preferred arrangement on an axle of the motor vehicle, two rotational spring bar systems oriented transversely to the vehicle longitudinal direction are provided, their motor-gear unit of the actuators being arranged, for example, in the region of the vertical vehicle longitudinal center plane. The torsion bars with the output levers may be positioned outboard therefor.

The above aspects of the invention are specifically set forth with respect to a coil spring element. As an alternative to the coil spring element and a coil spring element can be used. In the above-mentioned coil spring element, the turns extend in the axial direction, with a constant cross section along the longitudinal axis. Accordingly, the space required in the axial direction is comparatively large. In contrast, in a spiral spring element, the windings are substantially radially nested within one another in a common radial plane, with turns whose diameter increases radially outward. In this way, space can be saved in the axial direction of the spring element and is instead radially outside additional space required.

The advantageous embodiments and / or further developments of the invention explained above and / or reproduced in the dependent claims can be used individually or else in any desired combination with one another, for example in the case of clear dependencies or incompatible alternatives.

The invention and its advantageous embodiments and further developments and advantages thereof are explained in more detail below with reference to drawings.

Show it:

1 a plan view of the lower level of a left-side suspension of a rear axle of a motor vehicle, with a lower arm, a shock absorber and a torsion spring rod system;

2 an equivalent circuit diagram of the torsion bar system after the

1 with a representation of individual spring rates that essentially determine an overall spring rate;

3 in a unique position the torsion bar system, which in the in the 1 shown suspension is installed;

4 to 7 each different partial views of a torsion spring rod system according to a second embodiment;

8th and 9 each different views of a torsion spring rod system according to a third embodiment;

10 a torsion spring rod system according to a second embodiment with a spiral spring element; such as

11 . 12 and 13 each different sectional views of the in the 10 shown torsion bar system.

In the 1 is with 10 the lower level of a left-side suspension for a motor vehicle, with a lower arm 12 , on the one hand, on the vehicle body 20 (Especially on a vehicle body side subframe) and on the other hand on a not shown wheel carrier for a rear wheel 17 is articulated. The wheel carrier leading upper link is not apparent.

The in the 1 shown left-side suspension has a shock absorber 24 with separate suspension spring 21 (only in the equivalent circuit diagram of 2 indicated). The suspension arrangement according to the invention is according to the 1 from a in the vehicle transverse direction y extending torsion spring bar 22 as a memory spring yet to be described construction together.

The shock absorber 24 is at the lower wishbone 12 and above in a manner not shown on the vehicle body 20 supported.

The torsion bar 22 is in the 1 and 3 uniform material and in one piece from a first partial rod 23 and a second sub-bar 25 executed. The two part bars 23 . 25 are made of a solid material and an intermediate coil spring 26 connected with each other. The coil spring 26 points in the 1 and 3 a total of three, helically around a longitudinal axis L of the coil spring 26 guided turns 27 on, in each case the spring legs 29 connect. The spring legs 29 go in the 1 and 3 uniform material and in one piece in the two part bars 23 . 25 above. Of the two sub-bars 23 . 25 is the first partial staff 23 at a depository 39 from one on the vehicle body 20 attached cylindrical actuator 31 led out. The first part staff 23 is in a manner not shown in operative connection with an only indicated engine / gearbox / unit 33 of the actuator 31 , The housing of the actuator 31 is component stiff and non-rotatable to the vehicle body 20 supported.

The second partial staff 25 is also on a body-side pivot location 35 supported and at its transversely y outer end with a projecting in the direction of travel F of the motor vehicle forward output lever 38 educated, who about bearing points 42 ( 1 ) and an approximately vertically aligned coupling rod 40 articulated with the wishbone 12 connected is.

The engine / transmission unit 33 of the actuator 31 consists of a driving electric motor and a high-ratio gearbox (for example, a harmonic drive gearbox or a cycloid gearbox). The total spring rate c ₁ ( 2 ) of the torsion spring bar 22 determined solely by the spring rate of the coil spring 26 , but not from the rigid part bars 23 . 25 as well as the other components that are in the force path between the actuator 31 and the suspension element 12 are arranged.

In the 2 is shown in an equivalent circuit diagram, the interaction of the torsion bar system of the suspension. As a result, between the vehicle body 20 and the rear wheel 17 or the wishbone 12 the parallel connected spring systems c ₁ (the coil spring 26 of the torsion bar 22 ) and c ₂ (suspension spring 21 ) and effective, which determine the overall spring rate. By the coil spring 26 can the over the actuator 31 controlled spring rate c ₁ as a memory spring and associated with the total spring rate is reduced or advantageously adapted to structural conditions. For the sake of completeness is also the spring rate c _{3 of} the rear wheel 17 shown.

In the 4 to 7 a torsion spring rod system according to a second embodiment is shown. As a result, the first and second sub-bars are 23 . 25 as well as the coil spring 26 executed as individual parts, with the help of coupling parts 45 connected to each other.

According to the 4 to 7 are the two spring legs 29 the coil spring 26 Angled radially inward and aligned approximately at right angles to the longitudinal axis L. Corresponding is also a mounting hole 47 in the two coupling parts 45 aligned at right angles to the longitudinal axis L. In the two mounting holes 47 the coupling parts 45 are the spring legs 29 inserted radially from the outside. Each of the coupling parts 45 is by a first and a second clamping body 49 . 51 built up. Between the two clamping bodies 49 . 51 is the mounting hole 47 defined, in such a way that the spring leg inserted therein by indicated screw 53 is tightened. The first clamp body 49 protrudes according to the 7 with a measure b in the of the turns 27 limited cavity 55 into it. The second clamp body 51 on the other hand bears an axially outwardly projecting connecting pin 57 , which in the assembly position in plug connection with an end blind hole 59 (only in the 9 indicated) of the first or second partial rod 23 . 25 is. According to the 6 extends the connecting pin 57 in the assembly position coaxial with the longitudinal axis L of the coil spring 26 ,

In the 8th and 9 the torsion bar system according to another embodiment is shown. The basic structure and the mode of operation are identical to those of the multi-part construction according to the second exemplary embodiment of the invention 4 to 7 , In contrast to the second embodiment are in the 8th or 9 the two spring legs 29 not angled radially inward, but rather protrude axially outward as viewed in the axial direction. In addition, the two spring legs 29 acting as a lever arm transverse offset .DELTA.e to the longitudinal axis L of the coil spring 26 spaced. The two spring legs 29 are also in plug connection with associated mounting holes 47 the coupling parts 45 , The mounting holes 47 are in contrast to the previous embodiment, axially parallel to the longitudinal axis L of the coil spring 26 arranged. When changing the coil spring 26 are thus the two spring legs 29 compress axially to at least one of the two spring legs 29 from the mounting holes 47 lead out.

In the preceding embodiments of the 1 to 8th are the first and second sub-bars 23 . 25 respectively the coil spring element 26 interposed.

Alternatively, in the embodiment of the 10 to 13 the two sub-rods 23 . 25 a spiral spring element 26 interposed. For a particularly space-saving arrangement, this has the part bar 23 a larger diameter, hollow cylindrical or rotationally symmetrical primary part 49 in, in the formation of an annular gap 53 a smaller diameter abutment 51 of the second partial rod 25 protrudes. In between the primary and secondary parts 49 . 51 formed annular gap 53 is the spiral spring element 26 arranged. Alternatively, in the annular gap 53 Also, a coil spring element may be arranged, as used in the preceding embodiments.

According to the 11 has the spiral spring element 26 two turns 27 on, namely a smaller diameter, radially inner winding 27 and a radially outer winding 27 , The radially inner winding 27 has a spring leg projecting radially inwardly at right angles 29 on. This is a positive fit in a corresponding blind hole of the secondary part 51 of the second partial rod 25 used. Similarly, the at the radially outer winding 27 angled spring legs 29 also in a on the inner wall of the primary part 49 provided blind hole inserted form-fitting.

In the 11 is thus the spiral spring element 26 each in plug connection with the primary part 49 and the secondary part 51 , Instead of such a connector can according to the 13 also a butt joint, possibly with material connection (welding or gluing) can be realized. When in the 13 shown blunt butt joint is a radially inner spring leg 29 of the spiral spring element 26 with its front in impact with one on the abutment 51 molded projection 59 , Accordingly, the radially outer spring leg 29 with an inside on the hollow cylindrical primary part 49 molded projection 59 in a butt joint.

Claims (16)

Torsion spring rod system for a wheel suspension of a two-lane motor vehicle, with a variable torsion spring rod system, the vehicle body ( 20 ) arranged actuator ( 31 ), which has a torsion spring bar ( 22 ) with an output lever ( 38 ) with a biasing force on a suspension element ( 12 ) of the suspension, characterized in that the torsion bar ( 22 ) between the actuator ( 31 ) and the output lever ( 38 ) with a first partial rod ( 23 ) and a second partial rod ( 25 ) and an intermediate spiral or helical spring element ( 26 ) is executed. Torsion spring bar system according to claim 1, characterized in that the with the actuator ( 31 ) Actively connected first partial rod ( 23 ), the spiral or coil spring element ( 26 ) and the Output lever ( 38 ) carrying the second partial rod ( 25 ) are arranged coaxially with each other and / or in series one behind the other. Torsion spring bar system according to claim 1 or 2, characterized in that the spiral or coil spring element ( 26 ) Is enlarged cross-section compared to the partial rod cross-section. Torsion spring bar system according to one of the preceding claims, characterized in that the spiral or coil spring element ( 26 ) of the torsion bar ( 22 ) between two body-side bearings ( 35 ; 39 ), in which the first partial rod ( 23 ) and the second sub-bar ( 25 ) is rotatably mounted. Torsion spring bar system according to one of the preceding claims, characterized in that the spiral or coil spring element ( 26 ) a helical about a longitudinal axis (L) of the spiral or coil spring element ( 26 ) guided winding ( 27 ) which in the axial direction on opposite sides in spring legs ( 29 ) passes over. Torsion spring bar system according to claim 5, characterized in that the spring legs ( 29 ) protrude outwards in the axial direction and offset by a transverse offset (Δe) to the spiral or helical spring element longitudinal axis (L). Torsion spring bar system according to claim 5, characterized in that the spring legs ( 29 protrude inward in the radial direction and at right angles to the respectively assigned partial rod ( 23 ; 25 ) are arranged. Torsion spring bar system according to one of the preceding claims, characterized in that the first and second partial rods ( 23 ; 25 ) and the spiral or coil spring element ( 26 ) and optionally also the output lever ( 38 ) are of uniform material and / or in one piece. Torsion spring bar system according to one of the preceding claims, characterized in that the first and second partial rods ( 23 ; 25 ) and / or the spiral or coil spring element ( 26 ) are made of a solid material. Torsion spring bar system according to one of claims 1 to 7, characterized in that the first and second part rods ( 23 ; 25 ) as well as the spiral or coil spring element ( 26 ) at coupling points as individual parts, in particular detachably, are joined together. Torsion spring bar system according to claim 10, characterized in that between one of the part rods ( 23 ; 25 ) and a spring leg ( 29 ) a coupling part ( 45 ), and that the coupling part ( 45 ) at least one mounting hole ( 47 ), in which the spring leg ( 29 ) can be inserted. Torsion spring rod system according to claim 11, characterized in that the mounting hole ( 47 ) is aligned in the assembly position in the axial direction or at right angles to the axial direction. Torsion spring bar system according to claim 11, characterized in that the coupling part ( 45 ) in two parts with a first and a second clamping body ( 49 ; 51 ) is executed, between which the spring leg ( 29 ) of the spiral or coil spring element ( 26 ) is clamped. Torsion spring bar system according to claim 13, characterized in that the first clamping body ( 49 ) a connecting pin ( 57 ), for connecting the sub-rod ( 23 ; 25 ), and / or the second clamping body ( 51 ) at least partially into one of the at least one spiral or coil spring element winding ( 27 ) limited cavity ( 55 ) protrudes. Torsion spring bar system according to claim 1, characterized in that the first partial rod ( 23 ) a larger diameter, hollow cylindrical primary part ( 49 ) into which an annular gap is formed ( 53 ) a smaller diameter secondary part ( 51 ) of the second sub-rod ( 25 ) and that in between the primary part ( 49 ) and the secondary part ( 51 ) formed annular gap ( 53 ) the spiral spring element ( 26 ) is arranged. Torsion spring bar system according to claim 15, characterized in that the spiral or coil spring element ( 26 ) with a radially outer spring leg ( 29 ) in positive connection with the primary part ( 49 ) and with a radially inner spring leg ( 29 ) in positive connection with the secondary part ( 51 ).

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