EXHAUST SYSTEM SUSPENSION OF A VEHICLE

Description

Technical field

[0001] The invention relates to the technical field of automobiles, and in particular to connecting parts used to connect the exhaust line to the body of a vehicle. Prior art

[0002] When a vehicle is moving, it is subjected to accelerations along a vertical axis due to irregularities in the road on which it is traveling. The exhaust line is therefore also subjected to such accelerations. In order to ensure that the connection between the suspension and the body is not damaged, it is known to produce suspensions comprising a shock absorber to absorb the movements of the exhaust line relative to the body.

[0003] These movements are oriented: mainly in a vertical direction depending on the irregularities of the rolling surface of the road being traveled; to a lesser extent in a transverse direction depending on the centrifugal accelerations to which the exhaust line is subjected when the vehicle makes turns; and also in a longitudinal direction when the vehicle accelerates or decelerates along its route.

[0004] Various solutions are known from the prior art for connecting an exhaust line of a motor vehicle to the body of the vehicle with damping.

[0005] Document EP1378639 describes a hanger comprising a stamped sheet metal frame, and onto which is overmolded an elastomer body acting as a shock absorber between the movements of the exhaust line and those of the body.

[0006] However, this solution is not satisfactory because the manufacturing stages of this suspension are numerous. Its installation on the vehicle is not easy.

[0007] Furthermore, with this type of hanger, the movements of the exhaust line relative to the body are not sufficiently limited given the oscillatory movements of the exhaust line relative to the body. This hanger includes a stop glued to the frame, which involves two additional manufacturing steps: preparation of the frame (adhesion), then gluing the stop to the frame.

[0008] FR3086331 describes another suspension comprising an overmolded damping body. In this document, however, the stop is obtained by contact of two parts of the damping body against each other. The stop obtained is therefore not precise in position, the damping body being by nature deformable. Furthermore, the attachment of this suspension to the vehicle body can be improved.

[0009] Another suspension for connecting an exhaust line of a vehicle to a vehicle body is known from document DE 20 2007 009070 U1.

[0010] Finally, none of these solutions are optimized to limit the weight carried on the vehicle, which has an impact on fuel consumption. Statement of the invention

[0011] One of the aims of the invention is to overcome the drawbacks of the prior art by proposing an exhaust line hanger which is simple to manufacture, to install, efficient in use, and whose mass is reduced.

[0012] For this purpose, a suspension has been developed for connecting an exhaust line of a vehicle to a body of said vehicle, as defined in claim 1, the suspension comprising: a frame; a damping body made of elastomer material and having an oscillating part intended to receive an attachment of an exhaust line and to move elastically relative to the frame to dampen movements of the exhaust line; means for fixing the suspension to the body of the vehicle.

[0013] According to the invention, the frame is overmolded onto a portion of the fixing means, and the damping body is overmolded onto the frame.

[0014] In this way, the suspension is obtained in a particularly reduced number of steps, and can be automated.

[0015] In addition, the fixing means being directly included in the suspension, its installation on a vehicle is facilitated.

[0016] According to the invention, the overmolded damping body has a sleeve that surrounds a portion of the frame. By sleeve, we mean that this portion surrounds the section of the frame, being present on either side of the frame, on the side of the internal surface and that of the external surface. The sleeve constitutes an effective mechanical connection with the frame to transmit forces in all directions, both in thrust and in traction. This makes it possible to obtain very good mechanical strength of the damping body on the frame, while avoiding gluing the damping body to the frame by adhesion.

[0017] Preferably, the overmolded shock absorber body partially covers the frame, which allows certain parts of the frame to be left visible, and allows weight savings to be made by manufacturing the shock absorber body only to its necessary dimension. The parts left visible can constitute stops limiting the movements of the exhaust line relative to the body of the vehicle. In addition, these stops are clear, that is to say that the contact is made between a part of the shock absorber body, known to be flexible, and a part of the frame, known to be more rigid than the shock absorber body. The stopping position is therefore better controlled.

[0018] In order to limit the movements of the exhaust line in one direction and in both directions, the frame includes at least two stops to stop the movements of the oscillating part of the damping body.

[0019] To further limit the mass of the hanger, the frame is made of plastic.

[0020] According to a preferred embodiment, the frame is peripheral and defines an interior space, the oscillating part of the damping body is positioned in the interior space, and preferably the frame has projecting parts ensuring the maintenance of the overmolded damping body on the frame. The design obtained naturally lends itself to overmolding.

[0021] In order to ensure the rigidity and strength of the frame while limiting its mass, the frame is cylindrical in shape with radial ribs, for example defining a T, U, H shaped section.

[0022] Advantageously, the oscillating part is in the form of an axial sleeve connected by at least two, and preferably four suspension arms, to the peripheral part of the damping body, or connected to two diametrically opposed sleeves. The suspension arms give the suspension the desired dynamics and damping. The number of two and preferably four arms makes it possible to rationalize the section of the arms, in order to optimize the curing times of the damping body material during overmolding.

[0023] In order to combine the advantages of the above-mentioned technical characteristics, the frame has openings through which the suspension arms pass.

[0024] The invention also relates to a method of manufacturing a hanger intended to connect an exhaust line of a vehicle to a body of said vehicle, as defined in claim 10, the hanger comprising: a frame; a damping body made of elastomer material and having an oscillating part intended to receive an attachment of an exhaust line and to move elastically relative to the frame to dampen movements of the exhaust line; means for fixing the suspension to the body of the vehicle.

[0025] According to the invention, the method comprises the following successive steps: overmolding of the frame onto the fixing means; overmolding of the shock-absorbing body onto the frame, the shock-absorbing body having a sheath surrounding part of the frame.

[0026] In this way, the manufacturing process of the hanger is extremely simple, fast, and inexpensive. Brief description of the drawings

[0027] [ Fig. 1 ] is a perspective view, seen from above, of an example of a hanger which does not represent the invention. [ Fig.2] is a perspective view of means for attaching such a hanger. [ Fig.3 ] is a perspective view of a step in the manufacture of such a hanger. [ Fig.4 ] is a perspective, sectional view of an example of a hanger which does not represent the invention. [ Fig.5 ] is another perspective view, in section, of such a hanger. [ Fig.6 ] is another perspective view, in section, of such a hanger. [ Fig.7 ] is a front diagram of a hanger according to the invention. [ Fig.8 ] is a front diagram of another hanger according to the invention. [ Fig.9 ] is a front diagram of an example of a hanger which does not represent the invention. Detailed description of the invention

[0028] In reference to the figure 1which illustrates an example which does not represent the invention, the invention relates to a hanger (1) for a vehicle exhaust line, for example a car, mainly comprising fixing means (10), a frame (20) and a damping body (30).

[0029] The fixing means (10) is preferably a screw as illustrated figure 2 , but it can also be a smooth shaft configured to receive a pin, or any type of suitable fixing means

[0030] In the preferred embodiment illustrated, the fixing means (10) comprise a first part (11) threaded and intended to be connected to the body of the vehicle, and a second part (12) intended to be covered by the frame (20) during a first overmolding operation. The second part (12) has for this purpose a suitable geometry, with lobes (13) distributed angularly as well as shoulders (14) connecting the base of the lobes (13). These shapes will make it possible to reinforce the mechanical connection between the fixing means (10) and the frame (20) which will be overmolded on top.

[0031] The fixing means (10) are made of a material adapted to their mechanical function, for example metal and more precisely steel.

[0032] The frame (20) illustrated figure 3is obtained by a first overmolding step which consists of forming said frame (20) over the fixing means (10). The frame (20) is preferably made of plastic such as loaded Polyamide 66, and suitable for resisting external aggression.

[0033] The frame (20) has a flat base receiving the fixing means (10), this flat base is intended to come into contact with the body of the vehicle. The flat base has a projecting part intended to block the rotation of the hanger (1) when the fixing means (10) are assembled with the body.

[0034] The frame (20) has a generally cylindrical shape, with a peripheral external surface (25) and defining at its center an interior space (22). A rib (24) gives a “T” shape to the transverse section of the resulting cylinder. This section could be of another shape, for example “U”, “H” or “L”, the objective of this groove being to give the frame (20) the necessary mechanical resistance, while limiting the mass of the hanger (1). This rib (24) also participates in maintaining the damping body (30), in particular by blocking the peripheral part (32) of the damping body (30).

[0035] Ribs (23) are arranged at different locations on the frame (20) in order to reinforce the mechanical connection between the frame (20) and the damping body (30) which will then be overmolded on top. Certain ribs (23) are preferably arranged on the external surface (25) of the cylindrical shape of the frame (20).

[0036] In reference to the figures 1 , 4 , 5 and 6 , the damping body (30) is then overmolded onto the frame (20). The damping body (30) is made of an elastomeric material, such as ethylene-propylene-diene monomer or “EPDM”.

[0037] The damping body (30) comprises a peripheral part (32) covering the external surface (25) of the frame (20). In the case where the peripheral part (32) covers the entire circumference of the external surface (25), like a tire on a rim, the damping body (30) is thus perfectly secured to the frame (20), even when the exhaust line and the body of the vehicle are subjected to relative movements which the hanger (1) must absorb.

[0038] In the case where it does not cover the entire circumference of the external surface (25), the peripheral part (32) nevertheless gives the damping body (30) good cohesion with the frame (20), and is in particular resistant to the traction exerted by arms (33) whose operation is detailed below.

[0039] The frame (20) has visible notches or openings (26) figure 3 through its external surface (25). These openings (26) are configured so that, during overmolding of the damping body (30), material flows through these openings (26) and forms in the interior space (22) of the frame (20) an oscillating part (31) of generally cylindrical shape, and intended to be assembled with the exhaust line by means of an orifice present in its center.

[0040] Suspension arms (33) then connect the peripheral part (32) or the sleeves (36) to the oscillating part (31). The geometry of these arms (33) is designed to give them the elastic and dynamic characteristics necessary for damping the oscillations of the oscillating part (31).

[0041] The openings (26) of the frame (20) therefore make it possible to combine the aforementioned technical advantages, by making it possible to have a damping body (30) which is, firstly, suspended by arms (33), and secondly whose mechanical strength and retention on the frame (20) are guaranteed by the sleeves (36), or by the covering of a peripheral part (32), preferably over the entire circumference of the frame (20).

[0042] In all cases, the arms (33) are connected to material of the damping body (30) which is arranged outside the external surface (25) of the frame (20), whether it is sheaths (36) and / or a peripheral part (32). This connection is made at the right angle of the axes (33a) which are defined by the general direction of the arms (33), so that the oscillating part (31) is suspended, and that a traction applied to an arm (33) does not tend to detach the damping body from the frame (20), as in the solutions of the prior art which require adhesion. According to the invention, a traction applied to an arm (33) tends on the contrary to press the damping body (30) against the frame (20).

[0043] This design therefore makes it possible to avoid additional adhesion steps between the material of the damping body (30) and the material of the frame (20).

[0044] Preferably, the arms (33) are arranged in a substantially horizontal manner, so that they limit the transverse movements of the exhaust line relative to the body, by their resistance to compression and traction according to their direction of elongation.

[0045] The number of these arms (33) is at least two, and can be variable. The number of suspension arms (33) has a direct impact on their geometry, since the more arms (33) there are, the smaller their section. The smaller their section, the shorter the cooking time during overmolding.

[0046] In the preferred embodiment, arranging four arms (33) makes it possible to obtain an interesting compromise between their mechanical characteristics and the cooking time to be carried out.

[0047] The overmolding of the damping body (30) is partial, in the sense that certain parts of the frame (20) are not covered. In particular, stops (21) are left visible. These stops (21) serve to limit the movements of the oscillating part (31). Advantageously, the stops (21) obtained are said to be clear, because they will not deform under contact with the oscillating part (31).

[0048] In fact, the stops (21) are made of a rigid plastic material, the Young's modulus of which is generally between 0.4 and 6 GPa, while the oscillating part (31) is made of an elastomer material, the Young's modulus of which is generally less than 50 MPa.

[0049] Furthermore, making the stops (21) in the rigid material of the frame (20) allows weight savings to be achieved since less material is required to obtain the expected strength of the stops (21).

[0050] The hanger (1) preferably has two stops, in order to be able to limit the movements of the oscillating part (31) in both directions on a vertical trajectory.

[0051] The hanger (1) according to the invention is therefore manufactured in only two overmolding stages, which represents a gain in productivity.

[0052] The peripheral part (32) and the sheath (36) each contribute to the proper maintenance of the overmolded body (30) on the frame (20). Thus, the hanger (1) according to the invention can have: either a peripheral part (32) as well as one, and preferably two sheaths (36), as illustrated in figures 1 And 4 à 7 ; either one, and preferably two sheaths (36), but no peripheral part (32), as illustrated in the figure 8 .

[0053] There figure 9 illustrates another example of a hanger not representing the invention, with a peripheral portion (32) but no sheath (36).

[0054] There figure 8 illustrates an embodiment comprising two sleeves (36), diametrically opposed, without a peripheral part (32). The number of sleeves (36) is not imposed, but the presence of at least two sleeves (36) makes it possible to obtain a good distribution of the forces within the damping body (30), as well as good dynamic behavior of the oscillating part (31). It would be possible, for example, to provide three sleeves (36) distributed at 120°.

[0055] The hanger (1) may be shaped differently from the figures without departing from the scope of the invention, which is defined by the claims. In particular, the arms (33) or the oscillating part (31) may be shaped differently and be of any type suitable for the present application.

[0056] In a variant not shown, there are stops (21) on the transverse axis.

[0057] According to another variant not shown, there are only two arms (33).

[0058] According to another variant not shown, the peripheral part (32) does not cover the entire external surface (25) of the frame (20).

[0059] Furthermore, the technical characteristics of the various embodiments and variants mentioned above can be combined, in whole or in part, with each other. Thus, the hanger (1) can be adapted in terms of cost, functionality and performance.

Claims

1. Hanger (1) for connecting an exhaust line of a vehicle to the body of said vehicle, the hanger comprising: - a frame (20); - a damper body (30) made of elastomer material and having an oscillating part (31) intended to receive an attachment of an exhaust line and to move elastically relative to the frame (20) to dampen movements of the exhaust line; - means for fixing (10) the hanger (1) to the body of the vehicle; the frame (20) is overmolded on a part of the fixing means (10), and the damper body (30) is overmolded on the frame (20), characterized in that the damper body (30) has a sleeve (36) surrounding a part of the frame (20).

2. Hanger according to claim 1, characterized in that the overmolded damper body (30) partially covers the frame (20).

3. Hanger according to claim 1, characterized in that the frame (20) comprises at least two stops (21) for stopping the movements of the oscillating part (31) of the damper body (30).

4. Hanger according to claim 1, characterized in that the frame (20) is made of plastic material.

5. Hanger according to claim 1, characterized in that the frame (20) is peripheral and defines an interior space (22), the oscillating part (31) of the damper body (30) is positioned in the interior space (22), and the frame (20) has protruding parts (23) ensuring the retention of the overmolded damper body (30) on the frame (20).

6. Hanger according to claim 4, characterized in that the frame (20) is cylindrical in shape with radial ribs (24), for example defining a T, U, H-shaped section.

7. Hanger according to claim 4, characterized in that the damper body (30) comprises a peripheral part (32) covering the external surface (25) of the frame (20).

8. Hanger according to claim 6, characterized in that the oscillating part (31) is in the form of a sleeve connected by at least two, and preferably four, suspension arms (33) to the peripheral part (32) of the damper body (30).

9. Hanger according to claim 7, characterized in that the frame (20) has openings (26) through which the suspension arms (33) pass.

10. Method for manufacturing a hanger (1) intended to connect an exhaust line of a vehicle to the body of said vehicle, the hanger (1) comprising: - a frame (20); - a damper body (30) made of elastomer material and having an oscillating part (31) intended to receive an attachment of an exhaust line and to move elastically relative to the frame (20) to dampen movements of the exhaust line; - means for fixing (10) the hanger (1) to the body of the vehicle; the method being characterized in that it comprises the following successive steps: - overmolding the frame (20) on the fixing means (10); - overmolding the damper body (30) on the frame (20), the damper body (30) having a sleeve (36) surrounding a part of the frame (20)