KR20040110246A - torsion beam type suspension - Google Patents

Abstract

PURPOSE: A torsion beam-type suspension is provided to secure high bending strength and torsional rigidity without a torsion bar and a reinforcement by a torsion beam with large second moment of the area and polar moment of inertia. CONSTITUTION: In a torsion beam-type suspension, a pair of left and right trailing arms(22,22') is connected by a torsion beam(24). Front ends of the trailing arms mount a vehicle body by a joint(26,26'). A pipe with the predetermined thickness is pressurized and molded over the whole length of the torsion beam and the section of the torsion bean is formed like a hollow open ring. The trailing arm is composed of a first plate welded on the outer thickness of the end of the torsion beam and a second plate(22b,22'b) welded on the inner thickness of the end of the torsion beam.

Description

Torsion beam type suspension

The present invention relates to a torsion beam suspension system.

Suspension of a vehicle is a device that connects the vehicle body and the wheel, and absorbs the shock or vibration received from the road surface while driving to improve the ride comfort and stability of the vehicle. These suspensions are largely divided into one-piece in which the left and right wheels are connected to the axle and the independent type in which the left and right wheels operate separately. It consists of a shock absorber and an arm or a link that controls the operation of the wheel.

The torsion beam suspension, which is a kind of independent type, combines the left and right trailing arms into one member called the torsion beam or the cross beam, and has a longer link length and oscillation axis than the strut or double whistle. It features a low number of rubber bushes, low friction hysteresis in suspension strokes and a high level of smooth ride quality. It has been used mainly for light and quasi-rear suspensions for decades with relatively high running stability.

In the conventional torsion beam suspension device, as shown in FIG. 1, a pair of left and right trailing arms 2 and 2 'are connected by the torsion beam 4, and the trailing arms 2 and 2' are separated from each other. The front end pivotally supports the body (not shown) by the joints 6 and 6` with the rubber bush, and the wheels 8 and 8` are coupled to the rear ends of the trailing arms 2 and 2 '. Structure. In addition, a suspension spring (10.10 ') is provided between the trailing arms (2, 2') and the vehicle body, and shock absorbers (12, 12 ') are provided at the rear end of the trailing arms (2, 2'). Is connected.

The torsion beam suspension configured as described above is characterized by the deformation of the wheels 8 and 8` due to the torsional deformation characteristics of the torsion beam 4, and the bumps due to the torsional deformation and the position and bushing characteristics of the trailing arms. Toe-in: When looking down from the top of the wheel, the distance between the front of the two wheels is smaller than the rear distance.

In a torsion beam suspension, the trailing arm and the torsion beam are connected by welding, which is called a 'torsion beam axle'. The torsion beam axle is partially or completely twisted when the left and right wheels stroke in the opposite direction, and this torsion greatly affects the suspension system and is an important factor in determining the vehicle performance, which is actively used for the suspension function. Therefore, the torsion beam must have a high torsional rigidity against it when rolling the vehicle and a bending rigidity against the lateral force introduced through the tire when the vehicle is turning.

By the way, the conventional torsion beam is a beam manufactured by press-molding the cross section (open cross section), such as X, Y, and U, using a thick iron plate of about 4-5 mm as shown in FIG. Since the conventional torsion beam lacks the torsional rigidity, the bending rigidity, and the oral cavity resistance, the torsion bar for satisfying the torsional rigidity or the bending rigidity and the reinforcing material for satisfying the oral cavity resistance are separately welded to the torsion beam.

However, this type of conventional torsion beam has a problem in that the number of assembly increases according to the increase in the number of parts and the weight of the product increases.

Accordingly, the present invention has been made to solve the above problems, and to provide a torsion beam suspension device that can obtain a high torsional rigidity, bending rigidity and durability without the addition of additional components such as torsion bars or reinforcement.

1 is a perspective view showing a conventional torsion beam suspension device;

2 is a perspective view showing a torsion beam axle of a torsion beam suspension according to the present invention;

3 is a cross-sectional view taken along the arrow A-A in FIG.

4 is a bottom view of FIG. 2;

5 is a state diagram for shaping a torsion beam of the torsion beam suspension device according to the present invention.

<Explanation of symbols for the main parts of the drawings>

22, 22`: trailing arm 24: torsion beam

26, 26`: Joint 28, 28 ': Spindle bracket

32, 32 ': spring seat

In the present invention for achieving the above object, a pair of left and right trailing arms are connected by a torsion beam, and the torsion beam suspension device in which the front end of the trailing arm mounts the vehicle body by a joint, the torsion beam The pipe of predetermined thickness is press-molded over the whole length, The cross section is characterized by the hollow open ring form.

The trailing arm is integrally formed by welding a first plate shaped to be welded to the outer side thickness of the end of the torsion beam and a second plate shaped to be welded to the inner side thickness of the end of the torsion beam.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

As shown in Fig. 2, a pair of left and right trailing arms 22 and 22 'are connected by a torsion beam 24, and the front ends of the trailing arms 22 and 22' are jointed with rubber bushes. (26, 26 ') pivotally supports the vehicle body (not shown), and the spindle brackets 28, 28' are welded to the rear ends of the trailing arms 22, 22 'to engage the wheels, Spring seats 32, 32 'are welded on the trailing arms 22, 22' between the joint and the spindle bracket so that suspension springs are mounted. The wheels, suspension springs, shock absorbers, and the like are the same as those in FIG.

The torsion beam 24 is formed by pressing a pipe having a predetermined thickness over the entire length thereof, and having a cross section having an open ring having a hollow space S. As shown in FIG. It is a tubular torsion beam having a cross-sectional shape having an inner portion 24b. This cross-sectional shape has a large cross-sectional secondary moment and an inertia moment, and thus has high bending rigidity and torsional rigidity.

On both ends of the torsion beam 24, that is, the portion where the spring sheets 32 and 32 'are welded, the outer portion 24a on the cross section is cut out and the first plate of the trailing arm described later is extended and welded. Therefore, the length (L1: shown in FIG. 2) of the outer side 24a of the torsion beam 24 is shorter than the length (L2: shown in FIG. 4) of the inner side 24b.

The open ring shape of the cross section of the torsion beam 24 may be formed in various forms such as ∧, ∩ in addition to the cross sectional shape as shown in FIG.

The trailing arms 22, 22 'are formed with a first plate 22a, 22'a shaped to be welded to the thickness of the outer portion of the end of the torsion beam 24, and the inner portion of the end of the torsion beam 24. The second plates 22b and 22'b shaped to be welded to the thickness are integrated by welding, and the inside is a hollow member having a space therein. As shown in FIG. 2, the first plates 22a and 22'a are extended to be welded to the outer portion 24a of the torsion beam 24 to extend the second plates 22b and 22 toward the torsion beam 24 side. longer than 'b).

One end portion 32a, 32'a of the spring sheet 32, 32 'is welded to the outer surface of the extension portion (torsion beam side) of the first plates 22a, 22'a, and the other end portion ( 32b and 32'b are welded to the spindle bracket side of the second plates 22b and 22'b.

The tubular torsion beam 24 is made of a material having a high fatigue limit and sufficient strength so as to independently support the load supported by the conventional torsion beam, the reinforcement and the torsion bar. Therefore, the yield strength and tensile strength of the tubular torsion beam 24 are high, so that molding of the product is difficult.

The hydraulic molding method includes the upper and lower molds 40 and 42 for forming a circular pipe into an elliptical (including pillow) cross section, and an upper and lower punch 44 for forming an elliptical cross section into an open ring cross section of an oval shape. 46) and a feeding punch 48 for sealing both ends of the pipe and for operating the internal pressure, are molded in the press in the following order.

First, the pipe P is seated on the lower mold 42, and then the upper and lower molds 40 and 42 are operated to form a circular cross section into an elliptical cross section. Next, operate the elliptical feeding punch 48 mounted on the mandrel unit which is located at both ends of the pipe and operates in the longitudinal direction of the pipe, inserts it at both ends of the pipe, and then sprays the hydraulic fluid through the hole in the center of the feeding punch. The inner wall of the pipe is pressed to pressurize the inner wall of the pipe. Next, the upper and lower punches 44 and 46 are operated to form the outer portion 24a and the inner portion 24b of the torsion beam.

The hydraulic fluid is an incompressible fluid and regulates the pipe internal pressure through a servovalve. Since the internal space changes as the molding proceeds, the internal pressure of the pipe is kept constant through the servovalve so that other parts are not recessed during molding by the upper and lower punches.

According to the torsion beam suspension according to the present invention, by replacing the torsion beam with a tubular torsion beam in the form of an open ring having a hollow space (S), the torsion beam has a large cross-sectional secondary moment and polar moment of inertia. This results in high bending and torsional stiffness. Therefore, high torsional rigidity, bending rigidity, and endurance strength can be obtained without the torsion bar and the reinforcement that are necessarily assembled together in the conventional torsion beam axle, thereby reducing the number of parts and reducing the weight.

Claims (2)

In a torsion beam suspension device in which a pair of left and right trailing arms are connected by a torsion beam, and the front end of the trailing arm mounts the vehicle body by a joint. The torsion beam is a torsion beam suspension device, characterized in that the pipe of a predetermined thickness is press-formed over the entire length and its cross section is in the form of a hollow open ring. The method of claim 1, The trailing arm is, And a first plate shaped to be welded to the outer side thickness of the end of the torsion beam and a second plate shaped to be welded to the inner side thickness of the end of the torsion beam by welding.