MOTOR VEHICLE WITH FRONT CRADLE RECEPTING SUSPENSION ARMS

Abstract

A motor vehicle comprising a front subframe (2) equipped on each side with a suspension arm (10) including a rear elastic link (18) with this subframe (2), and a rear mounting (22) of the subframe (2) under the vehicle body, the elastic link (18) and the rear mounting (22) being traversed by a common screw (16) which simultaneously secures this elastic link (18) and this rear mounting (22). Figure 3

Description

Title of the invention: MOTOR VEHICLE WITH FRONT CRADLE RECEPTING SUSPENSION ARMS

[0001] The present invention relates to a motor vehicle comprising a front subframe receiving suspension arms, as well as a method for assembling such a vehicle

[0002] A known type of front cradle for a motor vehicle, presented in particular by document FR-A1-3029161, constitutes a rigid platform formed overall by two superimposed sheets, supporting the powertrain and the front axle suspension elements which can apply significant forces on this cradle.

[0003] The cradle receives on each side a lower front suspension triangle held by two pivots equipped with elastic links, fixed in the space between the two sheets of the cradle, comprising at the front a pivot having an axis arranged along the longitudinal direction of the vehicle and at the rear a pivot with a vertical axis.

[0004] The rear pivot includes a vertical screw fitted in a central tube of an elastomer block inserted in a bore of the suspension arm, which passes after this block through the upper sheet of the cradle to receive above a clamping nut fixing the block on this cradle.

[0005] Furthermore, in a known manner, the cradle has on each side, at the front and at the rear, a fixing under the body of the vehicle comprising a screw coming from below, which passes through this cradle and then a sheet under this body in order to receive above a nut for tightening the cradle.

[0006] It is then necessary to provide on each side of the cradle two distinct locations arranged generally one behind the other to receive the rear link of the suspension triangle and the rear fixing of the cradle under the body, presenting a high resistance to support significant forces, which pose problems of bulk, and of high mass given by the surfaces of the two sheets necessary to form these two successive locations, and by their added components.

[0007] In particular, for electric vehicles with a battery arranged flat under the passenger compartment floor, it is advantageous to provide a significant available length along the vehicle's longitudinal axis, offering a large surface area to accommodate a number of electrochemical cells that ensure the vehicle's range. In this case, it is possible to create a surface area under the floor towards the front, limited by the rear mounting of the subframe.

[0008] Furthermore, the components of the rear triangle link and the rear cradle fixing each comprise an elastomer block, an axial tube, a screw and a nut, This entails costs for purchasing and managing these components, and requires labor time to insert and screw them in, which adds costs.

[0009] The present invention is specifically intended to avoid these problems of the prior art.

[0010] To this end, it proposes a motor vehicle comprising a front cradle equipped on each side of a suspension arm comprising a rear elastic link with this cradle, and a rear fixing of the cradle under the body of the vehicle, this vehicle being remarkable in that the elastic link and the rear fixing are crossed by a common screw which simultaneously secures this elastic link and this rear fixing.

[0011] One advantage of this motor vehicle is that by aligning the two functions of rear cradle attachment and rear suspension arm elastic connection on the same axis of the common screw, without placing these functions side by side, a significant amount of space is freed up in the horizontal plane of the cradle. This reduces the sheet metal surfaces required to form the cradle, as well as the number of components needed to perform the functions, thereby decreasing the vehicle's mass.

[0012] In addition, with the rear cradle attachment advanced at the level of the rear elastic link of the suspension arm, a shorter cradle is made towards the rear, which in particular allows a traction battery box of the vehicle located under the floor of the passenger compartment to be extended forward.

[0013] Furthermore, with common components, including the single screw ensuring the maintenance of both functions, giving reduced labor time to ensure its positioning and tightening, the production costs of the vehicle are reduced.

[0014] The motor vehicle according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0015] Advantageously, the common screw passes successively through the rear elastic link, an upper sheet of the cradle, then a sheet of the vehicle body to fix itself above.

[0016] In this case, according to one embodiment the cradle has an upper face directly forming the support under the body sheet of the vehicle.

[0017] Alternatively, each rear attachment may include an elastic element connecting the cradle to the vehicle body.

[0018] In this case, advantageously the rear elastic fixing element is, along the axis of the common screw, superimposed on a first elastic element of the rear elastic connection.

[0019] In addition, the vehicle may include a single tube receiving the common screw, which passes through the first elastic element and the rear fixing elastic element.

[0020] In particular, the vehicle may include under the passenger compartment floor a box containing a traction battery for that vehicle.

[0021] The invention also relates to a method of assembling a motor vehicle comprising any one of the preceding characteristics, remarkable in that it includes a step of engaging a common screw in the rear elastic link and in the rear cradle fixing, and then a step of tightening this common screw.

[0022] The invention will be better understood and other features and advantages will become more apparent upon reading the following description given by way of example, with reference to the accompanying drawings in which:

[0023] [Fig-1] is a view of a cradle system according to the prior art;

[0024] [Fig.2] is a side view of this cradle system;

[0025] [Fig.3] is a side view of a cradle system according to the invention; and

[0026] [Fig.4] is a diagram showing in axial section the elastic connection and the fixation held by the same screw.

[0027] Throughout the document the upper or top direction is relative to a vehicle placed on a horizontal ground, the longitudinal direction represents the length of the vehicle, the front direction AV is relative to its direction of travel.

[0028] Figures 1 and 2 show a front cradle 2 of a motor vehicle comprising a lower sheet 4 receiving above an upper sheet 6 in order to form between them boxes ensuring significant rigidity.

[0029] A lower suspension arm 10 has a transverse part facing outwards from the vehicle, ending with a fixing of the base of the right front wheel pivot 12, and a longitudinal part comprising a front elastic link 14 and a rear elastic link 18 each having a screw 16 aligned along a vertical axis A, B.

[0030] Each elastic link 14, 18 comprises a cylindrical elastomer block inserted into a bore of the suspension arm 10, including an axial tube receiving the screw 16 from below, which after this tube passes through the upper plate of the platform 6 before receiving a nut 20 for tightening this link on the cradle 2. Pivoting of the two links 14, 18 is obtained along the longitudinal axis of the vehicle by deformation of the elastic block, and vibration filtering between the suspension arm 10 and the cradle 2.

[0031] Each side of the cradle 2 has a front fixing comprising a rising arm 8 ending in an elastomer block receiving a vertical fixing screw under a longitudinal member of the vehicle body.

[0032] For each side, a rear fixing 22 of the cradle 2 under the vehicle body, formed behind the rear elastic link 18, similarly comprises a screw 24 arranged along the vertical axis C, passing through a tube in the center of a block in elastomer having an outer contour linked to the cradle 2, then a sheet metal arranged under the body of the vehicle 26 in order to receive a fixing nut 28.

[0033] Following the longitudinal direction, the two functions arranged successively, of rear linkage of the arm 18 and of rear fixing of the cradle 22, give the cradle a length which extends far behind this arm to the detriment of other elements coming behind the cradle.

[0034] Fig. 3 shows the vertical screw 16 of the rear elastic link 18 of the suspension arm 10, which after passing through the tube of the elastic block of this link, then the upper plate of the cradle 6, passes through the plate under the body of the vehicle 26 in order to receive above the nut of this link 20.

[0035] The common screw 16 of the rear elastic link 18 of the suspension arm 10 is thus used to simultaneously fix the cradle 2 under the vehicle body, these two functions being arranged on the same vertical axis B / C. In the longitudinal direction, the length of the cradle 2 is reduced, which can stop just after the rear fixing 22.

[0036] In particular, for an electric or hybrid vehicle with a traction battery compartment located under the passenger compartment floor, this compartment can move forward into the space freed up by the shorter cradle 2. By increasing the number of electrochemical cells in the battery, the vehicle gains greater range.

[0037] On an example of a passenger vehicle, calculations show a total mass gain of this vehicle including a reduction in the mass of the cradle 2 of about 4kg, and a gain of more than 1kg for the elimination of the specific components required for the two rear cradle fixings 22 made independently.

[0038] The cost of the vehicle is reduced with in particular a front cradle requiring less sheet metal, the elimination of components, and a reduced vehicle assembly labor time including on each side of the cradle 2 the engagement and tightening of a common screw for the rear linkage of arm 18 and the rear cradle attachment 22.

[0039] Figure 4 shows an example of an elastic connection between a suspension arm 18 and a rear cradle mounting 22 using the common screw 16 for both functions, each with elastic isolation. The screw 16, fitted into a tube 30 with an upper end bearing under the body panel 26, receives the clamping nut 20 above this panel.

[0040] The tube 30 receives around its lower part a first elastic element 32 for retaining the suspension arm 10, and in its upper part a second elastic element 34 for retaining the cradle 2, which achieves a direct fixing of the arm and the cradle under the body of the vehicle with each providing vibration isolation.

Claims

Demands

1. Motor vehicle comprising a front cradle (2) equipped on each side with a suspension arm (10) comprising a rear elastic link (18) with this cradle (2), and a rear fixing (22) of the cradle (2) under the body of the vehicle, characterized in that the elastic link (18) and the rear fixing (22) are traversed by a common screw (16) which simultaneously secures this elastic link (18) and this rear fixing (22).

2. Motor vehicle according to claim 1, characterized in that the common screw (16) passes successively through the rear elastic link (18), an upper plate (6) of the cradle (2), then a plate of the vehicle body (26) to fix itself above.

3. Motor vehicle according to claim 2, characterized in that the cradle (2) has an upper face directly forming the support under the body sheet of the vehicle (26).

4. Motor vehicle according to claim 1 or 2, characterized in that each rear attachment (22) comprises an elastic element (34) connecting the cradle (2) to the vehicle body.

5. Motor vehicle according to claim 4, characterized in that the rear elastic fixing element (34) is, along the axis of the common screw (16), superimposed on a first elastic element (32) of the rear elastic linkage (18).

6. Motor vehicle according to claim 5, characterized in that it comprises a single tube (30) receiving the common screw (16), which passes through the first elastic element (32) and the rear elastic fixing element (34).

7. Motor vehicle according to any one of the preceding claims, characterized in that it comprises under the floor of the passenger compartment a box containing a traction battery for this vehicle.

8. Method of assembling a motor vehicle according to any one of the preceding claims, characterized in that it comprises a step of engaging a common screw (16) in the rear elastic link (18) and in the rear cradle fixing (22), and then a step of tightening this common screw (16).

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