VEHICLE STEERING RACK SYSTEM WITH ENGINE MOUNTING LINK BRACKET

Abstract

Steering rack system of a motor vehicle equipped with a powertrain (4), this system comprising an elongated rack housing (12) containing a sliding rack, having fixings on a vehicle cradle (2), and an end link support (24) of a connecting rod (20) for fixing the powertrain (4). Figure 2

Description

Title of the invention: VEHICLE STEERING RACK SYSTEM WITH ENGINE MOUNTING LINK SUPPORT

[0001] The present invention relates to a motor vehicle steering rack system comprising a powertrain mounting rod support, as well as a motor vehicle equipped with such a rack system and a method of assembling this vehicle.

[0002] A known type of motor vehicle, presented in particular by document FR-Al-3074453, comprises a powertrain arranged in the front compartment, which may be electrically driven, comprising several fixings on a cradle of the vehicle body forming a platform, equipped with elastic links to filter vibrations and noise.

[0003] A rear link arranged substantially horizontally, parallel to the longitudinal axis of the vehicle, includes elastic links fixed on one side to the rear face of the powertrain and on the other to the body of the vehicle, each forming a pivot having an axis arranged along the transverse direction of the vehicle, to transmit forces along the length of this link.

[0004] The rear linkage provides a torque recovery opposing the engine torque transmitted by the powertrain to the vehicle's wheels via the wheel shafts, in order to prevent it from tipping along the transverse direction.

[0005] The rear link also includes stops limiting the travel of its end pivots in order, in the event of a major front impact on the vehicle transmitting energy to the powertrain, to limit its tilting towards the rear which could lead to risks of intrusion into the passenger compartment and injury to the passengers.

[0006] Furthermore, document JP-B2-6543039 presents a steering rack arranged in a transversely elongated housing at the rear of the powertrain, which receives the movement of the steering wheel to slide by actuating the pivoting of the front wheels via bars fixed at the ends by ball joints.

[0007] It is known then to pass the rear connecting rod of the powertrain assembly over the rack housing to directly connect the rear face of this assembly to a support fixed on top of the cradle, behind this housing.

[0008] It should be noted that the steering rack and the powertrain supports, which can transmit significant forces, must have strong fixings. on the cradle which houses all the main components of the vehicle's front axle.

[0009] A connecting rod with a length greater than the width of the rack housing must be provided to pass over it, and then a specific fixing of the support of its rear link on the cradle which is added to the fixings of the rack housing located at the front.

[0010] We then have problems of bulkiness on the cradle which must have particular resistant anchor points for each element, the rack housing and the rear link of the tie rod, of added mass by the tie rod which is long and by the reinforcements of the cradle for the specific anchor points, and of cost for the preparation and installation of these different components.

[0011] The present invention is specifically intended to avoid these problems of the prior art.

[0012] To this end, it proposes a steering rack system for a vehicle automobile equipped with a powertrain, this system includes an elongated rack housing containing a sliding rack, having fixings on a cradle of the vehicle, this system being remarkable in that the rack housing includes an end link support for a powertrain fixing rod.

[0013] One advantage of this rack and pinion system is that by directly integrating the tie rod support onto the rack housing, the housing, forming a rigid assembly with a robust mounting to the vehicle body, is used to support the tie rod. This eliminates the need for a separate, robust mounting point on the vehicle body for the tie rod connection, thus simplifying its design. Component manufacturing costs and assembly time can be reduced, thereby lowering the overall cost.

[0014] In addition, the connecting rod can directly connect the powertrain to the rack housing which is generally located just behind it, without going behind this rack, which makes it possible to make a shorter connecting rod with a reduced mass and a reduced cost.

[0015] The rack system according to the invention may further comprise one or more of the following features, which may be combined with each other.

[0016] Advantageously, the end link support is along the axis of the rack, arranged in a central part of the elongated rack housing.

[0017] Advantageously, the end link support is arranged vertically above the rack.

[0018] Advantageously, the end link support is along the axis of the rack arranged next to a control part of the rack linking with a steering column.

[0019] Advantageously, the end link support includes a ring receiving inside an elastic link with the connecting rod.

[0020] In this case, the ring may have an axis which is parallel to the axis of the rack.

[0021] Moreover, advantageously the ring is formed in one piece by a molding with the rack and pinion housing.

[0022] The invention also relates to a motor vehicle equipped with a steering rack forming part of a rack system comprising any one of the preceding characteristics.

[0023] The motor vehicle may include an electric traction powertrain which is arranged in front of the rack housing.

[0024] The invention further relates to a method of assembling a vehicle comprising any one of the preceding characteristics, remarkable in that it includes a step of forming a sub-assembly comprising the rack system with the connecting rod fixed to it, and then a step of assembling this sub-assembly in the vehicle.

[0025] 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:

[0026] [Fig. 1] shows in side view an electric traction powertrain arranged in front of a rack system according to the prior art;

[0027] [Fig.2] shows in side view this powertrain arranged in front of a rack and pinion system according to the invention; and

[0028] [Fig.3] shows in rear view the powertrain and this rack and pinion system.

[0029] Throughout the document the upper or top direction is relative to a vehicle placed on a horizontal ground, the transverse direction is perpendicular to the longitudinal axis of the vehicle, the front direction AV is relative to its direction of travel.

[0030] The [Fig.1] shows a cradle 2 receiving towards the front AV a powertrain 4 comprising an electric traction machine 6 disposed above the axis of the differential 8 driving shafts connected to the drive wheels of the vehicle.

[0031] A steering column 10 having at its upper end the steering wheel located in the passenger compartment, has a lower end which enters a control part 18 fixed above the rack housing 12 forming a long-lined part, to control the axial sliding of the rack 14 arranged along the transverse direction of the vehicle.

[0032] The rack housing 12 is held rigidly by rack supports on top of the cradle 2, behind the powertrain 4, in order to obtain a connection resistant to the forces applied by the rack 14 on the steering wheels of the vehicle.

[0033] The rack housing 12 with its control part 18 comprises a housing formed in one piece by a casting in aluminium alloy.

[0034] A longitudinal torque-recovery link 20 has a front end connection 22 fixed on the rear face of the powertrain 4, and a rear end connection 24 comprising an elastic connection for filtering vibrations and noise.

[0035] The torque reaction link 20 opposes the torque transmitted by the powertrain 4 to the drive wheels, which is centered on the axis of the differential 8. The link 20 must also resist the significant forces applied to the powertrain 4 in the event of a violent impact on the front of the vehicle, in order to preserve the safety of the passengers.

[0036] A rear linkage support 26 for the connecting rod 24 fixed on the top of the cradle 2, behind the rack housing 12, has above it a ring 28 receiving inside an elastomer 30 which maintains a transverse axis 32 engaged in the rear end of the connecting rod 20.

[0037] We have, along the longitudinal direction, a distance DI between the transverse axis 32 of the rear link 24 and the front link 22, which takes into account the width of the rack housing 12 so as to be able to pass over it.

[0038] A relatively large distance DI is obtained, resulting in a long connecting rod 20 with high mass and cost. Furthermore, a supplementary part must be provided behind a strong portion of the cradle 2 for mounting the rack housing 12 to receive the rear support of the connecting rod 26, which adds mass and bulk.

[0039] Figures 2 and 3 show a rack housing 12 comprising, on the top of its longitudinal portion, next to the control portion 18, a rear linkage support 24 having a ring 28 which is formed directly by the metal casting of this housing. In particular, an additional slide is provided in the injection mold of the rack housing 12 to produce the ring 28. This results in a very limited amount of additional material, which only slightly increases the cost of the rack housing 12.

[0040] The ring 28 and the connecting rod 20 are arranged, along the axis of the rack 14, in the middle of the housing 12 and the powertrain 4, which gives symmetry with respect to the two wheel axes 40 transmitting a torque.

[0041] A transverse axis 32 of the rear linkage 24 is obtained, positioned substantially vertically above the axis of the rack 14, as close as possible to this rack, and as close as possible to the rear face of the powertrain 4, resulting in a very short connecting rod 20. The distance D2 between the transverse axis 32 of the rear linkage 24 and the front linkage 22 is significantly reduced compared to the prior art.

[0042] The rear connecting ring 28, formed directly by the molding of the rack housing 12, eliminates the need for the rear tie rod support 26, thereby reducing mass and cost. Furthermore, the cradle 2 incorporates only robust fasteners for the rack housing 12, without requiring additional fasteners for the rear tie rod 20, further simplifying its design and reducing its mass and cost.

[0043] Vehicle assembly time and labor costs are reduced, the fixing of the rack housing 12 on the cradle 2 automatically achieving the placement of the rear linkage of the tie rod 24.

[0044] Furthermore, for vehicle assembly, a sub-assembly can be prepared comprising the rack housing 12 fully equipped with its rack 14, receiving the rear tie rod 20 fixed by its rear linkage 24, which forms a sub-assembly delivered to the vehicle assembly workshop. This reduces the number of sub-assemblies to be supplied to this workshop and fitted to the vehicle, thus simplifying the final assembly operations of this vehicle.

Claims

Demands

1. Steering rack system of a motor vehicle equipped with a powertrain (4), this system comprising an elongated rack housing (12) containing a sliding rack (14), having fixings on a cradle of the vehicle (2), characterized in that the rack housing (12) has an end link support (24) of a connecting rod (20) for fixing the powertrain (4).

2. Rack system according to claim 1, characterized in that the end connecting support (24) is along the axis of the rack (14) disposed in a central part of the elongated rack housing (14).

3. Rack system according to claim 1 or 2, characterized in that the end connecting support (24) is arranged vertically above the rack (14).

4. Rack system according to any one of the preceding claims, characterized in that the end link support (24) is along the axis of the rack (14) disposed next to a rack control part (18) linking with a steering column (10).

5. Rack system according to any one of the preceding claims, characterized in that the end connecting support (24) comprises a ring (28) receiving inside an elastic connection with the connecting rod (20).

6. Rack system according to claim 5, characterized in that the ring (28) has an axis which is parallel to the axis of the rack (14).

7. Rack system according to claim 5 or 6, characterized in that the ring (28) is formed in one piece by a molding with the rack housing (12).

8. Motor vehicle equipped with a steering rack (14), characterized in that this rack (14) is part of a rack system according to any one of the preceding claims.

9. Motor vehicle according to claim 8, characterized in that it comprises an electric traction powertrain (4) which is arranged in front of the rack housing (12).

10. A method for assembling a vehicle according to claim 8 or 9, characterized in that it comprises a step of forming a sub-assembly comprising the rack system with the connecting rod (20) fixed thereto, and then a step of assembling this sub-assembly in the vehicle.

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