(19) TZZ Z__T

(11) EP 2 657 081 A1

(12) EUROPEAN PATENT APPLICATION

(43) Date of publication: (51) Int Cl.: 30.10.2013 Bulletin 2013/44 B60Q 1/46 (2006.01)

(21) Application number: 13173293.5

(22) Date of filing: 04.05.2009

(84) Designated Contracting States: (72) Inventor: Juriga, James Andrew AT BE BG CH CY CZ DE DK EE ES FI FR GB GR MI 48025 Beverly Hills (US) HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR (74) Representative: Delorme, Nicolas et al Cabinet Germain & Maureau (30) Priority: 02.05.2008 US 126426 BP 6153 69466 Lyon Cedex 06 (FR) (62) Document number(s) of the earlier application(s) in accordance with Art. 76 EPC: Remarks: 09746918.3 / 2 282 911 This application was filed on 21-06-2013 as a divisional application to the application mentioned (71) Applicant: Rassini S.A. de C.V. under INID code 62. Lomas de Chapultepec 11000 (MX)

(54) Dual leaf vehicle suspension with J-shaped spring element

(57) A vehicle suspension arrangement for a vehicle coupling to the chassis of the vehicle at a second pivot of the type having a chassis rail and a longitudinal axle coupling, and an axle coupler portion is arranged inter- arranged substantially orthogonal to the chassis rail has mediate of the first and second ends. A secondary leaf a primary spring with a predetermined resilience charac- spring has a first end for pivotally coupling to the chassis teristic, a first portion for coupling to the chassis of the of the vehicle at a pivot coupling, and a second end for vehicle at a primary coupling, and a second portion for coupling to the axle. A deflection limiting element is cou- coupling to the longitudinal axle. A primary leaf spring pled to a selectable one of the primary and secondary has a first end for pivotally coupling to the chassis of the leaf springs for controlling a distance therebetween. The vehicle at a first pivot coupling, and a second end for deflection limiting element is configured as a J-shaped spring element. EP 2 657 081 A1

Printed by Jouve, 75001 PARIS (FR) 1 EP 2 657 081 A1 2

Description mentemploys asolid axle, and therefore does not provide the benefits of independent suspension. In addition, this Relationship to Other Application known arrangement is plagued with the disadvantage of high unsprung mass. [0001] This application claims the benefit of the filing 5 [0006] A de Dion tube vehicle suspension arrange- date of Provisional Patent Application Serial Number ment is a known form of semi-independent suspension 61/126,426 filed May 2, 2008. The disclosure of this pro- andconstitutes an improvementover the Hotchkissdrive. visional patent application is incorporated herein by ref- In this type of suspension, universal joints are employed erence. at the wheel hubs and the differential, and there is addi- 10 tionally provided a solid tubular beam that maintains the Background of the Invention opposing wheels in parallel. The de Dion tube is not di- rectly connected to the chassis and is not intended to flex. FIELD OF THE INVENTION [0007] The benefits of a de Dion suspension include a reduction in the unsprung weight compared to the Hotch- [0002] This invention relates generally to suspension 15 kiss drive. This is achieved by coupling the differential to systems for vehicles, and more particularly, to a leaf sus- the chassis. In addition, there are no camber changes pension arrangement that employs a dual leaf suspen- during suspension unloading. Since the camber of both sion with a main spring deformation reduction element wheels is set at zero degrees, the traction from wide tires disposed therebetween on a substantially "J" or "L" is improved, and wheel hop under high power operations shaped spring support element. 20 is reduced compared to an independent suspension. However, the de Dion tube adds unsprung weight. DESCRIPTION OF THE RELATED ART [0008] It is, therefore, an object of this invention to pro- vide a vehicle suspension arrangement that provides the [0003] Leaf spring systems have for many years been benefits of independent suspension while using leaf used for the suspension of wheeled vehicles. The central 25 spring technology. element of a leaf spring suspension system for a vehicle [0009] It is another object of this invention to provide is termed a "semi-elliptical" spring configured as an arc- a vehicle suspension arrangement that employs leaf shaped length of spring steel having a substantially rec- spring technology and yet affords reduced unsprung tangular cross-section. At the center of the arc is provided mass for reduced inertial effects and improved vehicle an arrangement for coupling to the axle of the vehicle. 30 handling response. At the ends are provided coupler holes for attaching the [0010] It is also an object of this invention to provide a spring to the vehicle body. For heavy vehicles, leaf vehicle suspensionarrangement that employs leaf spring springs are stacked on one other to form layers of springs technology and affords reduced suspension inertia. of different lengths. Leaf springs are still used in heavy [0011] It is a further object of this invention to provide commercial vehicles and railway carriages. In the case 35 a vehicle suspension arrangement that employs leaf of very heavy vehicles, leaf springs provide the advan- spring technology and affords reduced noise, vibration, tage of spreading the load over a larger region of the and harshness (NVH). vehicle’s chassis. A coil spring, on the other hand, will [0012] It is additionally an object of this invention to transfer the load to a single point. provide a vehicle suspension arrangement that employs [0004] The well-known Hotchkiss drive, the name of 40 leaf spring technology and affords reduced lateral wheel which derives from the French automobile firm of Hotch- shake. kiss, employs a solid axle that is coupled at its ends to [0013] It is yet a further object of this invention to pro- the centers of respective semi-elliptical leaf springs. vide a vehicle suspension arrangement that employs leaf There are a number of problems with this form of drive spring technology and affords reduced side view wind- arrangement. First, this drive system is characterized by 45 up at the axle bracket. high unsprung mass. Additionally, the use of a solid axle [0014] It is also another object of this invention to pro- results in coupled left/right wheel motion. During heavy vide a vehicle suspension arrangement that employs leaf cornering and fast acceleration, this known system suf- spring technology and affords reduced forward and rear- fers from vertical deflection and wind-up. ward movement. [0005] One prior art effort to address the problems as- 50 [0015] It is yet an additional object of this invention to sociated with the Hotchkiss system employs a parallel provide a vehicle suspension arrangement that employs leaf spring arrangement at each end of a solid axle. This leaf spring technology and affords a semi-independent known arrangement affords increased axle control, in the suspension effect during asymmetric wheel travel. form of reduced power hop. Other advantages of this [0016] It is yet an additional object of this invention to known arrangement include roll under steer, auto load 55 provide a vehicle suspension arrangement that employs leveling and the gross vehicle weight, and no frame leaf spring technology in combination with a coil spring changes are required to convert from a Hotchkiss sys- element. tem. However, the known parallel leaf spring arrange-

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Summary of the Invention [0021] In accordance with a further apparatus aspect of the invention, there is provided a vehicle suspension [0017] The foregoing and other objects are achieved arrangement for a vehicle of the type having a chassis by this invention which provides a vehicle suspension rail and a longitudinal axle arranged substantially orthog- arrangement for a vehicle of the type having a chassis 5 onal to the chassis rail. A principal resilient element has rail and a longitudinal axle arranged substantially orthog- a determinable resilience characteristic, the principal re- onal to the chassis rail, the vehicle suspension arrange- silient element having a first portion for coupling to the ment. In accordance with a first apparatus aspect of the chassis of the vehicle and a second portion for coupling invention, there is provided a primary leaf spring that has to the longitudinal axle. A secondary leaf spring is pro- a plan view longitudinal configuration, a first end for piv- 10 vided having a plan view longitudinal configuration, a first otally coupling to the chassis of the vehicle at a first pivot end for pivotally coupling to the chassis of the vehicle at coupling, and a second end for coupling to the chassis a secondary pivot coupling, and a second end for cou- of the vehicle at a second pivot coupling, and an axle pling to the longitudinal axle. Additionally, there is pro- coupler portion arranged intermediate of the first and sec- vided a deflection limiting element coupled to the sec- ond ends. Additionally, there is provided a secondary leaf 15 ondary leaf spring for limiting the extent of a leaf spring spring having a plan view longitudinal configuration, a deflection. first end for pivotally coupling to the chassis of the vehicle [0022] In an embodiment of the invention where the at a pivot coupling, and a second end for coupling to the principal resilient element is an air- pressure-assisted pri- longitudinal axle. There is advantageously provided a de- mary spring, such an air spring has a resilience charac- flection limiting element coupled to a selectable one of 20 teristic that is responsive to air pressure, a first portion the primary and secondary leaf springs for controlling a for coupling to the chassis of the vehicle at a primary distance therebetween. The plan view longitudinal con- coupling, and a second portion for coupling to the longi- figuration of the secondary leaf spring is arranged at a tudinal axle. In other embodiments, the principal resilient predetermined angular displacement with respect to the element is a coil spring. chassis rail, which in some embodiments of the invention 25 [0023] In one embodiment of this further apparatus as- may be substantially parallel thereto. pect of the invention, there is provided a pivot coupling [0018] In one embodiment of this aspect of the inven- arrangement disposed intermediate of the second por- tion, there is optionally provided a principal resilient ele- tion of the secondary leaf spring and the longitudinal axle. ment illustratively in the form of a spring having a prede- [0024] In a further embodiment of the invention, there termined resilience characteristic. The optional principal 30 is provided a primary leaf spring having a plan view lon- resilient element is, in one embodiment, a spring having gitudinal configuration, the first portion being a first end a first portion for coupling to the chassis of the vehicle at for pivotally coupling to the chassis rail of the vehicle at a primary coupling, and a second portion for coupling to a first primary pivot coupling, and there is also provided the longitudinal axle said principal spring and the second a further end distal from the first end for pivotally coupling end of said secondary leaf spring each communicate with 35 to the chassis rail of the vehicle at a second primary pivot respective portions of the longitudinal axle at respective coupling. The second portion for coupling to the longitu- longitudinal regions of the longitudinal axle. The principal dinal axle is arranged intermediate of the first an further spring is, in one embodiment of the invention, an air- ends of the primary leaf spring. The primary leaf spring assisted resilient element. In other embodiments, the is arranged to communicate with the deflection limiting principal spring is a coil spring. 40 element. [0019] In one embodiment of the invention, the deflec- [0025] In a highly advantageous embodiment of the tion-limiting element is a J-shaped spring element. It is invention, a pivot coupling arrangement is disposed in- to be understood, however, that other configurations, termediate of thesecond portion of the primaryleaf spring such as an L-shaped spring element; a C- shaped spring and the longitudinal axle. element; a pillar, or I-shaped spring element; a closed, 45 [0026] In a further embodiment, the secondary leaf or O-shaped spring element; a U- shaped spring element; spring is arranged to be angularly displaced with respect or any other suitable configuration. In this disclosure, the to the primary leaf spring. The first primary pivot coupling term "J-shaped spring element" shall be deemed to en- and the secondary pivot coupling are, in some embodi- compass all such alternative embodiments and equiva- ments, arranged to be substantially coplanar. lents thereof. 50 [0027] In accordance with a further apparatus aspect [0020] In some embodiments, the plan view longitudi- of the invention, there is provided a suspension arrange- nal configuration of the secondary leaf spring is arranged ment for a vehicle having a leaf spring element having a at an angle with respect to the chassis rail of the vehicle, substantially longitudinal configuration, and a deflection the second end of the secondary leaf spring being ar- limiting element coupled to the leaf spring element. ranged to communicate with a respective portion of the 55 [0028] There is further provided in some embodiments longitudinal axle that is axially displaced along the longi- a further leaf spring element for constituting a dual leaf tudinal axle relative to the respective portion thereof that suspension arrangement in combination with the leaf is engaged with the air assisted primary spring. spring element, the leaf spring element being disposed

3 5 EP 2 657 081 A1 6 whereby the deflection limiting element is intermediate spring element, and the beneficial effect that is of the leaf spring element and the further leaf spring el- achieved when the J-shaped spring element is em- ement. ployed (Fig. 6(b)). [0029] In a highly advantageous embodiment, the de- flection limiting element comprises a J- shaped spring el- 5 Detailed Description ement that is coupled to one of the leaf spring elements. In some embodiments,there is further provided a resilient [0034] Fig. 1 is a perspective representation of a spe- contact element attached to the J- shaped spring element cific illustrative embodiment of the invention. As shown for communicating with the other leaf spring element in this figure, a vehicle suspension system 100 has a [0030] In accordance with a method aspect of the in- 10 chassis that is generally designated as chassis 110. The vention, there is provided a method of controlling a ride chassis has a pair of substantially parallel chassis rails characteristic of a vehicle of the type that is provided with 112a and 112b that are coupled to one another by cross- a dual leaf suspension having first and second leaf ele- braces 116 and 118. ments. The method includes the step of limiting the dis- [0035] A differential drive arrangement 120 is fixedly tance between the first and second leaf elements. In this 15 coupled to the chassis and converts the rotatory motion manner, excessive deflection of one of the leaf spring of a drive shaft 122 to substantially orthogonal rotatory elements, as might result from braking or acceleration, motion at half shafts 125a and 125b. Each half shaft has and that would illustratively decrease the distance be- an associated pair of universal joints (not specifically tween the first and second leaf elements, is precluded. designated) that are arranged to be proximal and distal [0031] In one embodiment of this method aspect of the 20 with respect to the differential drive arrangement. Thus, invention, the step of limiting the distance between the the half shafts, each of which has an associated longitu- first and second leaf elements includes the step of inter- dinal axis (not shown), accommodate transaxial motion, posing a deflection limiting element between the first and particularly by operation of the proximal universal joints. second leaf elements. In some embodiments, the deflec- [0036] Half shafts 125a and 125b are shown to be cou- tion limiting element is a J- shaped spring element that is 25 pled at their distal ends to respective leaf springs 130a coupled to one of the first and second leaf elements. and 130b. Referring to leaf spring 130a, for example, the [0032] In other embodiments of this method aspect of leaf spring is, in this specific illustrative embodiment of the invention, there is further provided the step of provid- the invention, pivotally coupled at its forward end to a ing a principal resilient element in combination with the bracket 132a. At its rearward end, leaf spring 130a is first and second leaf elements. 30 pivotally coupled to a link 134a. As shown in this figure, there is additionally provided a half leaf spring 136a that Brief Description of the Drawing is also, in this specific illustrative embodiment of the in- vention, coupled at its forward end to bracket 132a. At [0033] Comprehension of the invention is facilitated by its rearward end, half leaf spring 136a is coupled to the reading the following detailed description, in conjunction 35 distal end of half shaft 125a. Half leaf spring 136a is with the annexed drawing, in which: shown in this specific illustrative embodiment of the in- vention, to engage a fulcrum 133a. Fig. 1 is a perspective representation of a specific [0037] In this embodiment of the invention, there is at- illustrative embodiment of the invention; tached to half leaf spring 136a a J- shaped spring element Fig. 2 is a side plan simplified schematic illustrations 40 160. J-shaped spring element 160 is, in this specific il- of a rotary joint suspension arrangement and a J- lustrative embodiment of the invention, coupled to half shaped spring element constructed in accordance leaf spring 136a by two fasteners (not specifically desig- with the principles of the invention; nated in this figure). J-shaped spring element 160, addi- Fig. 3 is a simplified lateral plan representation of tional elements of structure related thereto, such as an the half leaf spring with the J- shaped spring element 45 elastomeric fulcrum element (not shown in this figure) attached thereto; disposed between the J- shaped spring element and leaf Fig. 4 is a simplified schematic representation of a spring 130a, and its kinematic and other effects on the side view of a suspension system constructed in ac- characteristics of half leaf spring 136a and leaf spring cordance with the principles of the invention with a 130a, will be described in greater detail below. A further 1st stage consisting of a coil spring; 50 J-shaped spring element is, in the practice of the inven- Fig. 5 is a simplified schematic representation of a tion, installed on half leaf spring 136b. However, the fur- side view of a suspension system constructed in ac- ther J-shaped spring element on half leaf spring 136b is cordance with the principles of the invention with a not shown in this figure for sake of clarity of the figure. 1st stage consisting of an air-pressure responsive [0038] There is additionally shown in this figure a trans- resilient element in the form of an air spring; and 55 verse beam 140 that is coupled to cross- brace 116 by a Figs. 6(a) and 6(b) are simplified schematic repre- damper 142 and to cross- brace 118 by a further damper sentations that illustrate the stresses that result from 144. Transverse beam 140 has installed thereon a piv- leaf spring wind-up (Fig. 6(a)) without the J-shaped oting member 150 to which are attached link elements

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152and 154. Thelink elements are attached, via brackets half leaf spring 210 by means of fasteners 162. The J- (not specifically designated), to cross-brace 118. shaped spring element has installed thereon a fulcrum [0039] It is to be understood that the inventive J- element 164 formed, for example, of an elastomeric ma- shaped spring element 160 described herein is not lim- terial. J-shaped spring element 160 has at each of its ited in its application to the specific suspension arrange- 5 ends, terminations 168 that facilitate pivotal coupling of ment represented in Fig. 1. Persons of skill in the art, in the J-shaped spring element to the chassis (not shown light of the teaching herein, will be able to generate ad- in this figure) and the axle (not shown in this figure) in a ditional embodiments of the J- shaped spring element as conventional manner. required to be accommodated within other vehicle sus- [0044] Fig. 4 is a simplified schematic representation pension arrangements. Such additional embodiments 10 of a side view of a suspension system constructed in may include, for example, a J- shaped spring element that accordance with the principles of the invention with a 1st more closely resemble an L-shaped spring element, as stage consisting of a coil spring. Elements of structure shown in the schematic representation of Fig. 6 (b); a C- that have previously been discussed are similarly desig- shaped spring element (not shown); a pillar, or I- shaped nated. Coil spring 455 provides vertical load support in spring element (not shown); a closed, or O- shapedspring 15 combination with first stage leaf spring 457. A lower leaf element (not shown); a U-shaped spring element (not 460 of the 2nd stage is employed for additional control. shown); or the like. However, for purposes of the descrip- In this specific illustrative embodiment of the invention, tion of the invention herein presented, the term "J- shaped the center of axle 411 travels along a path that conforms spring element" shall be deemed to encompass all such to curved arrow 462, as seen in the present side view. alternative embodiments and equivalents thereof. 20 In accordance with the invention, J-shaped spring ele- [0040] Fig. 2 is a side plan simplified schematic illus- ment 160 is shown to be coupled to lower leaf 460 by trations of a rotary joint suspension arrangement 200 and means of fasteners (not specifically designated in this further having J-shaped spring element 160 constructed figure). As previously noted, in other embodiments of the in accordance with the principles of the invention. Ele- invention the J-shaped spring element is coupled to first ments of structure that bear analogous correspondence 25 stage leaf spring 457, such other embodiments not being to elements of structure that have previously been dis- shown. cussed are similarly designated in this figure. Referring [0045] Fig. 5 is a simplified schematic representation to Fig. 2, it is seen that there is provided a leaf spring of a side view of a suspension system constructed in 130a that, in this specific illustrative embodiment of the accordance with the principles of the invention with a 1st invention, ispivotally coupled at its forward and rear ends, 30 stage consisting of an air-pressure responsive resilient as previously described. There is additionally provided a element in the form of an air spring 455a. Elements of half leaf spring 210 that is also, in this specific illustrative structure that have previously been discussed are simi- embodiment of the invention, pivotally coupled at a pivot larly designated. Air spring 455a provides vertical load mount 212 at its end distal to a further pivotal mounting support in combination with first stage leaf spring 457. 213 at a coupling member 214. The coupling member is 35 As described above in relation to Fig. 4, lower leaf 460 itself coupled to axle shaft 215. of the 2nd stage is employed for additional control. Cent- [0041] Fig. 2 further illustrates a pivot link mounting er of axle 411 travels along a path that conforms to curved arrangement 220 wherein leaf spring 130a is securely arrow 462, as seen in the present side view. In accord- clamped between clamping member 222 and 224. ance with the invention, J- shaped spring element 160 is Clamping member 224 is coupled to a pivot joint 226 that 40 shown to be coupled to lower leaf 460 by means of fas- is itself engaged with coupling 214. This arrangement teners (not specifically designated in this figure). permits a further degree of motion that reduce system [0046] Figs. 6(a) and 6 (b) are simplified schematic rep- internal loading on the pivot joint arrangement and leaf resentations that illustrate the stresses that result from spring elements. leaf spring wind-up (Fig. 6(a)) without the shaped J- [0042] In accordance with the invention, there is pro- 45 spring element, and the beneficial effect that is achieved vided J-shaped spring element 160 coupled to half leaf when the J-shaped spring element is employed (Fig. 6 spring 210 by means of fasteners 162. J-shaped spring (b)). The schematic representations of these figures rep- element has a fulcrum element 164 formed, in this spe- resent computer models of the stresses applied in an cific illustrative embodiment of the invention, of an elas- embodiment of the invention installed on a Chrysler tomeric material. Fulcrum element 164, as will be de- 50 heavy duty truck (3500 series). As shown in Fig. (a),6 scribed below, communicates with leaf spring 130a to there is not provided a J- shaped spring element, and the effect an advantageous change in the overall spring char- resulting wind-up of the primary leaf spring results in a acteristic of the vehicle suspension. stress applied that exceeds 1700 MPa. The rotational [0043] Fig. 3 is a simplified lateral plan representation displacement resulting from this wind- up stress is on the of the half leaf spring with the J-shaped spring element 55 order of 18.43°, which translates into a stiffness param- attached thereto. Elements of structure that have previ- eter of approximately 34.5 Nm/degree. ously been discussed are similarly designated. As shown [0047] Fig. 6(b) illustrates computer- modeled stresses in this figure, J-shaped spring element 160 coupled to that are applied to the leaf spring elements when the J-

5 9 EP 2 657 081 A1 10 shaped spring element is employed (shaped substantial- 5. The suspension arrangement of claim 2 wherein the ly as an L- shaped spring element). As shown, the primary J-shaped spring element is coupled to the additional spring experiences a range of stresses from less than leaf spring element. 700 MPa to approximately 660.85 MPa. Thus, the stress is reduced considerable by implementation of the J-5 6. The suspension arrangement of claim 2 wherein the shaped spring element. In addition, it is noted that the leaf spring element and the additional leaf spring el- rotational displacement resulting from this wind- up stress ement are arranged in a substantially parallel rela- is on the order of 4.40°, which translates into a stiffness tionship relative to each other. parameter of approximately 152 degree. Nm/ This equates to an increase in stiffness by a factor of 4.41, 10 7. The suspension arrangement of claim 1 further com- without significant increase in unsprung mass. prising a principal resilient element having a deter- [0048] Although the invention has been described in minable resilience characteristic, the principal resil- terms of specific embodiments and applications, persons ient element having a first portion for coupling to the skilled in the art may, in light of this teaching, generate chassis of the vehicle and a second portion for cou- additional embodiments without exceeding the scope or 15 pling to a longitudinal axle arranged substantially or- departing from thespirit ofthe invention described herein. thogonal to a chassis rail. Accordingly, it is to be understood that the drawing and description in this disclosure are proffered to facilitate 8. A method of controlling a ride characteristic of a ve- comprehension of the invention, and should not be con- hicle having a dual leaf suspension with first and sec- strued to limit the scope thereof. 20 ond leaf elements, the method comprising the step of limiting the distance between the first and second leaf elements with a J-shaped deflection limiting el- Claims ement disposed between the first and second leaf elements, the deflection limiting element coupled to 1. A suspension arrangement for a vehicle, the sus- 25 one of the first and second leaf elements at an inter- pension arrangement comprising: mediate location relative to a first end and a second end of the second leaf element. a leaf spring element having a substantially lon- gitudinal configuration; 9. The method of claim 8 further comprising providing a deflection limiting element coupled to said leaf 30 a principal resilient element in combination with the spring element at an intermediate location there- first and second leaf elements. of, wherein said deflection limiting element com- prises a J-shaped spring element; and a resilient element coupled at a first portion to a chassis of the vehicle and at a second portion 35 to a longitudinal axle of the suspension arrange- ment.

2. The suspension arrangement of claim 1 further com- prising an additional leaf spring element, the leaf 40 springelement and the additional leaf springelement forming a dual leaf suspension arrangement, where- in the J-shaped spring element is disposed interme- diate of the leaf spring element and the additional leaf spring element. 45

3. The suspension arrangement of claim 2 wherein the leaf spring element comprises a first end for pivotally coupling to a chassis of the vehicle at a first pivot coupling, and a second end for coupling to the chas- 50 sis of the vehicle at a second pivot coupling.

4. The suspension arrangement of claim 3 wherein the additional leaf spring element comprises a first end for pivotally coupling to the chassis of the vehicle at 55 a pivot coupling, and a second end for coupling to a longitudinal axle arranged substantially orthogonal to a chassis rail.

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REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description

• US 61126426 B [0001]

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