Tuning freedom degree improvement type bush and suspension system

1. A bush, comprising:

a second inner pipe forming a central protrusion in a central section of the second inner pipe;

an outer pipe forming a third protrusion at a first inner side and a fourth protrusion at a second inner side, wherein the third and fourth protrusions are arranged outside of the central protrusion; and

a rubber part provided between the second inner pipe and the outer pipe,

wherein the outer pipe includes:

an end protrusion flange to form a locking fixing force for a front end mass of the rubber part, and

an end bending flange to form an adhesive fixing force for a rear end mass of the rubber part,

wherein the second inner pipe forms: a first protrusion at a position corresponding to the third protrusion, and a second protrusion at a position corresponding to the fourth protrusion,

wherein the central protrusion, the first protrusion and the second protrusion are connected to each other forming a wave-shaped body of the second inner pipe and each comprise at least one of a flat upper surface or a flat lower surface such that a radius length of the central protrusion, the first protrusion and the second protrusion is greater than a width length thereof.

2. The bush of claim 1 ,

wherein the first protrusion, the second protrusion, and the central protrusion are arranged along a front and rear direction of a vehicle.

3. The bush of claim 1 ,

wherein the rubber part comprises: a first void between the first protrusion and the third protrusion and a second void between the second protrusion and the fourth protrusion.

4. The bush of claim 3 ,

wherein the first void and the second void are arranged along a front and rear direction of a vehicle.

5. The bush of claim 4 ,

wherein a cutout is formed on the rubber part at an upper portion and a lower portion of the rubber part along a vertical direction of the vehicle.

6. The bush of claim 1 ,

wherein the second inner pipe is a composite of elastomer using plastic and rubber or urethane.

7. The bush of claim 1 ,

wherein an inclination of the central protrusion of the second inner pipe and inclinations of the third and fourth protrusions, which are configured to face the central protrusion, are arranged to be in the same direction as each other.

8. The bush of claim 1 ,

wherein the central protrusion has a pipe contact portion, and a width of the pipe contact portion is greater than a width of a protrusion formed at an end part of the second inner pipe.

9. The bush of claim 1 ,

wherein the third protrusion and the fourth protrusion are arranged in a front and rear direction of a vehicle.

10. The bush of claim 1 , wherein:

the outer pipe has a central recess positioned at the central protrusion of the second inner pipe,

an inclination of the central recess faces inclinations of a first protrusion and a second protrusion of the second inner pipe,

the first protrusion is disposed at a position corresponding to the third protrusion, and the second protrusion is disposed at a position corresponding to the fourth protrusion,

the inclinations of the central recess, the first protrusion and the second protrusion are arranged in the same direction as each other, and

the central recess forms a width of a pipe contact portion of the outer pipe and the width of the pipe contact portion is greater than a width of a protrusion formed at an end part of the second inner pipe.

11. The bush of claim 1 ,

wherein the second inner pipe forms a coupling structure of a first inner pipe, the coupling structure includes a seating groove of the first inner pipe and a seating protrusion of the second inner pipe.

12. The bush of claim 1 ,

wherein the second inner pipe forms a close contact structure with a first inner pipe via a contact protrusion formed on an outer surface of the first inner pipe.

13. The bush of claim 1 ,

wherein the second inner pipe surround a first inner pipe to be integrated with together, and the first inner pipe is made of an aluminum material.

14. A suspension system, comprising:

the bush of claim 1 , wherein the bush is configured to:

provide a bush modulus of elasticity that is a combination of a plastic modulus of elasticity of engineering plastic forming the second inner pipe and a rubber modulus of elasticity of rubber forming the rubber part, and

provide a tuning freedom degree with a rigidity tuning by the plastic modulus of elasticity and an elastic tuning by the rubber modulus of elasticity; and

a trailing arm fastened with a wheel at an opposite side of a vehicle body fastening part formed through the bush.

15. The suspension system of claim 14 ,

wherein the trailing arm is coupled to end portions of left and right sides of a torsion beam to be configured as a Coupled Torsion Beam Axle (CTBA).