WO2018192601A1

WO2018192601A1 - Roll stabilizer for a motor vehicle

Info

Publication number: WO2018192601A1
Application number: PCT/DE2018/100107
Authority: WO
Inventors: Markus Klinger
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2017-04-20
Filing date: 2018-02-08
Publication date: 2018-10-25
Also published as: DE102017108373A1

Abstract

The invention relates to a roll stabiliser (1) for a motor vehicle, comprising a torsion bar (2) with a first and a second distal end (3a, 3b), the two distal ends (3a, 3b) being embodied in a tubular manner and designed to at least partially axially receive a base body (5) of a respective welding bushing (4), the respective welding bushing (4) also comprising a collar (6) that axially rests on the respective distal ends (3a, 3b), on the front side, said collar (6) being weldable to the respective distal ends (3a, 3b). The base body (5) of the respective welding bushing (4) has a knurl profile (7) on the periphery thereof, and can be pressed axially into the respective distal end (3a, 3b) in order to form a positive and non-positive knurl interference fit, and ventilation grooves (8) for evacuating a gas created during the welding process are embodied radially between the base body (5) and the inner diameter of each distal end (3a, 3b).

Description

Roll stabilizer for a motor vehicle

Roll stabilizer for a motor vehicle, comprising a torsion bar having a first and second distal end, wherein the two distal ends are tubular and are provided to at least partially axially receive a main body of a respective weld bushing.

Usually, each wheel axle of a motor vehicle on a roll stabilizer, which operates on the torsion bar principle. The roll stabilizer is arranged substantially parallel to the vehicle axle and at both ends via a respective

Coupling rod connected to the suspension. Furthermore, the roll stabilizer is provided to stabilize the body structure against unwanted rolling movements about the longitudinal axis of the motor vehicle. Such rolling movements occur, for example, when cornering of the motor vehicle. The rolling motion of the motor vehicle is influenced by the roll stabilizer by the compression movement of the left and right wheel suspension of an axle is coupled together using the roll stabilizer.

DE 10 2013 205 903 A1 discloses a roll stabilizer for a vehicle. The roll stabilizer comprises an actuator for generating a torsional moment about a torsion axis, wherein the actuator has a housing arrangement, and wherein the roll stabilizer has at least one stabilizing component, in particular a torsion bar spring. The stabilization components are usually powder-coated. From DE 10 2015 009 604 A1, a weld-in bushing with a flange is also known, via which the weld-in bushing can be welded to a carrier element. The weld-in bushing has at least one side facing the carrier element during welding, at least one gas emerging through the gas flowing through the recess.

The object of the present invention is to further develop a roll stabilizer of a motor vehicle and in particular to provide a solid and cost-effective connection between a torsion bar and a welding bushing. A roll stabilizer for a motor vehicle according to the invention comprises a torsion bar having a first and a second distal end, the two distal ends being tubular and intended to at least partially axially receive a main body of a respective weld bush, wherein the respective weld bushing further comprises a collar, which comes to rest axially against the respective distal end, wherein the collar is weldable to the respective distal end, wherein the main body of the respective weld bushing circumferentially has a Rändelprofil, wherein the main body is axially pressed into the respective distal end to form a and frictional Rändelpressverband to form, and wherein radially formed between the base body and the inner diameter of the respective distal end vent grooves for discharging a gas generated during welding. The term knurl dressing is basically a shaft-hub connection to understand in which the main body of the weld bush, the shaft and the respective distal end of the torsion bar represents the hub. The advantage of a knurling press fit is the ease of manufacture, the lower press-in forces compared to the classic, cylindrical press fit, and the low demands on dimensional tolerances and freedom from backlash. The lower insertion forces allow a higher coverage of the joining partners. As a result, the operational stability of the connection can be increased by improved support of the bushing in the pipe and thereby resulting relief of the weld. The knurling profile is to be understood as meaning the toothing produced on the main body of the weld-in bush by means of a knurling process. The knurled profile serves both as a forming tool, as well as a power transmission element. By an axial press-fitting the counter toothing required for the transmission of force is formed in the inner diameter of the respective distal end. Particularly advantageous is the thus matched toothing in the shaft hub part, which on the one hand ensures an extremely uniform transmission of force through the centering. On the other hand, the weld bush is frictionally connected by the radial overlap with the torsion bar. The knurling compound is essentially intended to relieve the weld produced in the welding process. In other words, the main body of the weld bushing is within the respective distal end of the Trunnion supported, whereby the forces acting on the weld forces are reduced.

Furthermore, the joining forces during the press-fitting process of the welding bushing into the respective distal end are reduced by the geometric design of the knurling profile. On the one hand, this improves the manufacturability of the knurling press dressing, and on the other hand an increase in the overlap between the main body and the respective distal end is possible. Under the overlap is the radial excess of body of the weld bushing and the respective pipe end to understand. Thus, by a reduced joining force enlargement of the coverage is possible, which in turn has positive effects on the support of the weld and thus on the durability of the compound.

The vent grooves formed radially between the base body and the inner diameter of the respective distal end ensure adequate ventilation during the welding process. The resulting gases during welding escape to the one in the radial direction to the outside, on the other they escape from the weld root radially into the gap inwards, where they flow into the axial vent grooves and can be discharged in the direction of the tube interior. This ensures compliance with the required weld quality by avoiding pore formation in the weld.

The invention includes the technical teaching that the main body is cylindrical, wherein the respective vent grooves are formed in parallel to the main body in distributed on the circumference of the body knurled valleys of the knurled profile. In other words, the vent grooves are groove-shaped in the knurled valleys.

Preferably, the outer diameter of the main body is greater than the inner diameter of the respective distal end, wherein at least the inner diameter in the region of the knurl valleys at least partially plastically deformed. For example, the torsion bar made of a first metallic material and the respective welding bush made of a second metallic material, wherein the first metallic material has a lower strength than the second metallic Material. In other words, the knurling profile forms a counter-geometry formed essentially complementary to the geometry of the knurl profile in the inner diameter of the respective distal end. In particular, not the entire inner diameter will be plastically deformed to ensure the press fit, since in this case the radial coverage needed for power transmission would be lost.

The knurled profile preferably has knurling points, which penetrate into the respective distal end during a press-fitting process of the respective base body in order to form a non-positive connection in the radial direction and a positive connection in the direction of rotation. The material of the respective distal end fills the vent groove partially. Alternatively, the material strengths of the first and second metallic materials can be selected to be similar, so that both the inner diameter of the torsion bar and the knurled profile partially plastically deform during the press-in process and both materials have a material hardening in the contact area.

Furthermore, the knurling profile preferably has the form RAA according to DIN 82. This is to be understood as meaning a knurl with axially parallel grooves, the knurling tips being spaced apart from one another and being distributed uniformly around the circumference of the basic body. The knurling tips have a height that is substantially the radial difference between the knurling tip and the knurling tip. Furthermore, the knurling valleys have an opening angle, wherein the height of the knurling tip and the opening angle of the knurling valley define the cross-sectional area of the ventilating grooves. A design of the knurled profile with axially parallel grooves is particularly advantageous in the axial pressing of the main body in the respective distal end, since a backlash-free connection with direct power transmission is formed.

According to a preferred embodiment, the collar or flange of the respective welding bushing can be welded to the end face of the respective distal end of the torsion bar by a fusion welding process. Particularly preferred is the TIG welding process, since it is a relatively fast process and has only little gas and slag formation in the welding process, whereby this process is particularly clean and the torsion bar due to the short heat input. Effect not significantly deformed. Alternatively, the weld can also be produced by a laser welding process, which also has a reduced formation of gas and slag, as well as a reduced heat input. Preferably, the collar of the respective weld bushing is welded circumferentially at the respective distal end. Consequently, this results in a sealing of the knurl extrusion dressing against external influences such as splashing water. Further preferably, the torsion bar is coatable after the welding of the respective collar with the respective distal end by means of powder coating. The advantage here is the protection against external influences and chemical stress of the torsion bar interior, in particular corrosion. In particular, the coating can additionally improve the sealing effect produced by the welding night.

Further measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to the figures, wherein the same or similar elements are provided with the same reference numerals. Show it

FIG. 1 shows a schematic view of a roll stabilizer according to the invention,

2 shows a schematic partially cutaway perspective view of a first distal end of a torsion bar of the roll stabilizer according to the invention, FIG. 3 shows a simplified schematic detail sectional view for illustrating a press-fitting process of a welding bush into the first distal end of the torsion bar;

FIG. 4 shows a schematic detail sectional view for illustrating the welding bushing received at the first distal end in the pressed-in state,

Figure 5a is a simplified schematic sectional view illustrating a knurled profile in a non-pressed state, and Figure 5b is a simplified schematic sectional view illustrating the knurled profile in a pressed state. According to FIG. 1, a roll stabilizer 1 for a motor vehicle (not shown here) comprises a torsion bar 2 with first and second distal ends 3a, 3b, wherein the two distal ends 3a, 3b are tubular. Alternatively, the roll stabilizer 1 can also be formed by means of an actuator - not shown here - and two torsion bar halves. The roll stabilizer 1 is arranged transversely to the longitudinal axis of the vehicle and connected at its free ends to wheels or wheel carriers (not illustrated here).

FIGS. 2 to 5 each show the left side of the torsion bar 2 with the first distal end 3a. The - not shown - right side of the torsion bar 2 may be formed analogous to the left side, but it can also be provided an alternative embodiment of the second distal end 3b shown in Figure 1. In Figure 2, the first distal end 3a of the torsion bar 2 is provided to axially receive a main body 5 of a weld bushing 4, wherein the main body 5 of the shaft of the weld bushing 4, and wherein the weld bushing 4 further comprises a collar 6, the front side of the first distal end 3a comes axially to the plant.

According to FIG. 3, the basic body 5, which is illustrated schematically in simplified form, comprises a circumferential knurling profile 7, wherein the base body is pressed into the first distal end 3a in a press-fit direction during the press-fitting operation in order to form a positive and non-positive knurled dressing to build. The knurling profile is designed in the form RAA according to DIN 82 with axially parallel grooves. During welding, and in particular during fusion welding, gases are produced, in particular from anticorrosion coatings or from alloying elements of metallic materials. Furthermore, in the welding process, gases can arise from the welding consumable used and the protective gas, the welding electrode, as well as impurities on the surface of the welding bush or the torsion bar. If, owing to insufficient ventilation, air inclusions or gas inclusions occur in the weld seam 1 1 shown in FIG. 4, the strength of the welded joint between welded joint socket 4 and the first distal end 3a reduced. In order to improve the ventilation during the welding process, ventilation grooves 8 are formed radially between the main body 5 and the inner diameter of the first distal end 3a for the purpose of discharging a gas produced during welding. Furthermore, the vent grooves 8 are provided to allow escape of air during the press-fitting operation of the weld bushing 4. This additionally leads to a reduction of the required press-in force for the weld bushing 4. The vent grooves 8 are distributed on the circumference of the main body 5. Further, the vent grooves 8 are formed axially parallel to the main body 5. The length of the vent grooves 8 corresponds to the length of the main body 5. By the radial coverage of the

Base 5 of the weld bushing 4 to the first distal end 3a of the knurled dressing is relieved of the weld seam 1 1, thereby increasing the fatigue strength of the welded joint. According to Figure 4, the base body 5 is cylindrical and axially received by the first distal end 3a. The collar 6 is also cylindrical and has a larger outer diameter than the main body 5. Further, the collar 6 is welded by a weld 1 1 with the first distal end 3a. By welding the weld bush 4 over the collar 6, the weld bushing 4 can be welded over a particularly large area and therefore firmly with the torsion bar 2. During welding, at least one weld 1 1 is produced, wherein the weld 1 1 is formed circumferentially here and seals a torsion bar interior 14 of the torsion bar 2 against external influences, such as splashing water. The weld seam 1 1 is formed by means of a TIG welding process, wherein the peripheral edges of the collar 6 and of the first distal end 3 a adjacent to the weld seam 1 are chamfered. The weld bushing 4 further has a bore 13 for at least partially receiving at least one - not shown here - fastener, which is connectable to the weld bushing 4, wherein the bore 13 may be formed, for example, as an internally threaded bore det.

In the figures 5a and 5b, the base body 5 is shown with the knurled profile 7 in a partial cross-section. The knurled valleys 9 and the knurling tips 10 are formed alternately and uniformly distributed on the circumference of the main body 5. An unequal moderate arrangement of the knurling tips 10 and knurls 9 is also conceivable. According to Figure 5b, the vent groove 8 is groove-shaped and has a substantially triangular cross-sectional area. The outer diameter of the main body 5 is formed larger than the inner diameter of the first distal end 3a. Further, the torsion bar 2 is formed of a first metallic material and the respective weld bush 4 made of a second metallic material. Furthermore, the first metallic material has a lower strength than the second metallic material. The knurling tips 10 penetrate during the pressing process into the material of the torsion bar 2, wherein the inner diameter of the first distal end 3a is at least partially plastically deformed. Thus, in the radial direction, a frictional connection and in the direction of rotation forms a positive connection between weld bushing 4 and torsion bar 2. The material of the torsion bar 2 fills in the press-fitting the vent groove 8 radially partially. The radial distance between the knurling 9 and the inner diameter of the first distal end 3a is decisive for the venting effect during the press-fitting operation and during the welding operation.

LIST OF REFERENCE NUMBERS

1 roll stabilizer

2 torsion bar

3a, 3b distal end

4 welding bush

5 basic body

6 fret

7 knurled profile

8 vent groove

9 knurled valley

10 knurled tip

1 1 weld

12 pressfit

13 hole

14 Rotating bar interior

Claims

claims

1 . A roll stabilizer (1) for a motor vehicle, comprising a torsion bar (2) having first and second distal ends (3a, 3b), the two distal ends (3a, 3b) being tubular and intended to form a base body (5) of one the respective weld bushing (4) further comprises a collar (6) which comes to rest on the end face at the respective distal end (3a, 3b) axially, wherein the collar (6) with the respective distal end (3a, 3b) is weldable,

characterized in that the base body (5) of the respective weld bushing (4) circumferentially has a knurled profile (7), wherein the base body (5) axially in the respective distal end (3a, 3b) can be pressed to form a positive and non-positive thumbwheel and radially formed between the base body (5) and the inner diameter of the respective distal end (3a, 3b) are ventilation grooves (8) for discharging a gas generated during welding.

2. roll stabilizer (1) according to claim 1,

characterized in that the base body (5) is cylindrical, wherein the respective vent grooves (8) in the circumference of the base body (5) distributed Rändeltälern (9) of the knurled profile (7) are formed axially parallel to the base body (5).

3. roll stabilizer (1) according to claim 1,

characterized in that the outer diameter of the base body (5) is greater than the inner diameter of the respective distal end (3a, 3b), wherein at least the inner diameter is at least partially plastically deformed.

4. roll stabilizer (1) according to one of the preceding claims,

characterized in that the torsion bar (2) made of a first metallic material and the respective weld bushing (4) are formed from a second metallic material, wherein the first metallic material has a lower strength than the second metallic material.

5. roll stabilizer (1) according to any one of the preceding claims, characterized in that the knurled profile (7) has knurled tips (10) which penetrate during a press-fitting process of the respective base body (5) in the respective distal end (3a, 3b) to form a positive connection in the radial direction and a positive connection in the direction of rotation.

6. roll stabilizer (1) according to any one of the preceding claims,

characterized in that the knurled profile (7) has the shape RAA according to DIN 82.

7. roll stabilizer (1) according to one of the preceding claims,

characterized in that the collar (6) of the respective weld bush (4) is frontally welded to the respective distal end (3a, 3b) of the torsion bar (2) by a fusion welding process.

8. roll stabilizer (1) according to any one of the preceding claims,

characterized in that the collar (6) of the respective welding bushing (4) is welded circumferentially at the respective distal end (3a, 3b).

9. Roll stabilizer (1) according to one of the preceding claims,

characterized in that the torsion bar (2) after the welding of the respective collar (6) with the respective distal end (3a, 3b) can be coated by means of powder coating.