Patent Publication Number: US-2015084300-A1

Title: Chassis module and camber angle adjustment

Description:
BACKGROUND 
     Camber angle or camber is commonly known as the measurement taken between true vertical and a vertical axis of a vehicle wheel. A wheel having negative camber is presented by an upper portion of the wheel tilting laterally inward toward a longitudinal axis of the vehicle, and/or a lower portion of the wheel tilting laterally outward away from the longitudinal axis of the vehicle. A wheel having positive camber is presented by the upper portion of the wheel tilting laterally outward from the longitudinal axis of the vehicle, and/or a lower portion of the wheel tilting laterally inward toward the longitudinal axis of the vehicle. Automotive manufacturers develop and produce vehicles with recommended camber specifications, corresponding with suspension design and other wheel alignment specifications that may satisfy, for example, vehicle handling and tire wear expectations. 
     Many vehicles have a wheel assembly securely attached to a suspension system by adjustable fastener mechanisms for adjusting the camber. In particular, the suspension system may include a generally vertical suspension strut including a knuckle assembly operably connected to a lower portion of the strut. The knuckle may then be secured to a wheel spindle that in turn connects to the wheel. These suspension systems may include cam bolts, eccentric washers fastened to the bolts by key-and-notch features formed in the outer circumference of the bolts, and detent features formed on a sub-frame to engage the washers and move the bolt inboard or outboard for adjusting camber. These adjustable fastener mechanisms may add weight and increase costs. 
     It would therefore be desirable to provide chassis module and method for adjusting camber while reducing the weight and cost of these modules. 
     SUMMARY 
     One exemplary vehicle chassis module may include a knuckle, a sub-frame and a camber control link coupled to at least one of the knuckle and the sub-frame via a slot and a surface surrounding the slot. The vehicle chassis module may also include a bolt fastener received in the slot and having a head corresponding with the surface, such that the bolt fastener remains at a fixed position along the slot when torque is applied to the bolt fastener and the head rotatably slides across the surface. 
     Another exemplary vehicle chassis module may include a sub-frame, a knuckle and a camber control link coupled to at least one of the sub-frame and the knuckle via a clevis. The clevis includes a pair of slots and a pair of surfaces surrounding a respective one of the slots. The vehicle chassis module may further include a bolt fastener disposed in the slots, and a nut fastener engaged to the bolt fastener to attach the camber control link to the sub-frame or the knuckle. The bolt fastener may have a head corresponding with one of the surfaces of the clevis, and the nut fastener may correspond with the other of the surfaces, such that the bolt fastener remains at a fixed position along the slots when torque is applied to at least one of the bolt fastener and the nut fastener. 
     An exemplary method for adjusting camber of a vehicle chassis module may include attaching the chassis module to a tooling fixture. The tooling fixture may be operated to adjust the camber of the chassis module. The method may further include rotating a head of a bolt fastener across a planar surface to hold the bolt fastener at a fixed point along a slot in the planar surface and hold the camber of the chassis module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one exemplary chassis module having a camber control link coupled to a sub-frame to hold a wheel at a predetermined camber, without using a cam mechanism or shim mechanism at a joint between the camber control link and the sub-frame and a joint between the camber control link and the knuckle; 
         FIG. 2  is an enlarged view of the exemplary joint for the chassis module as taken from circle  2  shown in  FIG. 1 ; 
         FIG. 3  is a top view of the chassis module shown in  FIG. 1 ; 
         FIG. 4  is an enlarged view of the exemplary joint for the chassis module as taken from circle  4  shown in  FIG. 3 ; 
         FIG. 5  is a cross-sectional view of the joint for the chassis module shown in  FIG. 4 , as taken along line  5 - 5 ; 
         FIG. 6  is a cross-sectional view of an exemplary joint between an outboard end of a the camber control link and a knuckle of the chassis module of  FIG. 1 ; 
         FIG. 7A  is an enlarged top view of another exemplary joint between an inboard end of the camber control link and the sub-frame; 
         FIG. 7B  is an enlarged top view of yet another exemplary joint between an outboard end of the camber control link and the knuckle; and 
         FIG. 8  is a flowchart for one exemplary method for adjusting camber of the vehicle chassis module shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the discussion that follows and also to the drawings, illustrative approaches are shown in detail. Although the drawings represent some possible approaches, the drawings are schematic in nature and thus not drawn to scale, with certain features exaggerated or removed to better illustrate and explain the present disclosure. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description. 
     An exemplary chassis module and method for adjusting camber of the same is provided. The chassis module may have a sub-frame, a knuckle and a camber control link that is coupled to the sub-frame or the knuckle at a joint via a slot. Two examples of the joint between the sub-frame and the camber control link include the slot formed in the sub-frame or the slot formed in an inboard end of the camber control link. Two examples of the joint between camber control link and the knuckle include the slot formed in the knuckle or the slot formed in the outboard end of the camber control link. The bolt fastener may attach the camber control link to a surface surrounding the slot. The bolt fastener may have a head corresponding with the surface, such that the bolt fastener remains at a fixed position along the slot when torque is applied to the bolt fastener and the head rotatably slides across the surface. 
     The exemplary method for adjusting camber of a vehicle chassis module may include attaching the chassis module to a tooling fixture. The tooling fixture may be operated to adjust the camber of the chassis module. The method may further include rotating a head of a bolt fastener across a planar surface to hold the bolt fastener at a fixed point along a slot in the planar surface and hold the camber of the chassis module. 
     Referring to  FIG. 1 , one exemplary multilink chassis module  100  is illustrated. The chassis module  100  may include a wheel hub  102 , upon which a wheel (not shown) may be mounted. The wheel hub  102  may have a face  104  used as a reference surface to measure camber during, for example, assembly of the chassis or maintenance of the vehicle. However, other suitable portions of the wheel hub  102  or chassis module  100  may be used to measure the camber. 
     With further reference to  FIG. 1 , the chassis module  100  may also include a lower control link  106  (hereinafter “toe control link”) and an upper control link  108  (hereinafter “camber control link”), which is spaced vertically apart from the toe control link  106 . The toe control link  106  is used to adjust toe, also known as tracking. Toe is the symmetric angle that each wheel makes with the longitudinal axis of the vehicle, in contrast to steer, which is the anti-symmetric angle, i.e., both wheels point to the left or right, roughly in parallel. Positive toe, or toe in, is presented by the front of the wheel pointing in towards the longitudinal axis of the vehicle. Negative toe, or toe out, is presented by the front of the wheel pointing away from the longitudinal axis of the vehicle. Toe can be measured in linear units, at the front of the tire, or as an angular deflection. 
     The toe control link  106  may have an outboard end  110  operably connected to the wheel hub  102 . In particular, in this example, the outboard end  110  is pivotally attached to a knuckle  111  that in turn is rotatably coupled to the wheel hub  102 . The toe control link  106  may also have an inboard end  112  pivotally coupled to a lower portion  114  of a sub-frame  116 , such that the toe control link  106  may point a wheel mounted to the hub  102  in a direction or heading relative to a longitudinal axis of the vehicle. In this respect, the toe control link  106  may be adjusted to change the symmetric angle that each wheel makes with respect to the longitudinal axis of the vehicle. 
     Referring again to  FIG. 1 , the camber control link  108  provides the chassis module  100  with the desired camber, e.g., within specification for the associated vehicle, by operably holding the wheel hub  102  and the sub-frame  116  in fixed positions with respect to each other. During assembly, camber may be adjusted by mounting the chassis module  100  in a tooling fixture and moving the camber control link  108  laterally inward or outward generally along an axis  136  that extends generally between the sub-frame  116  and the wheel hub  102 . The camber control link  108  has an outboard end  118  pivotally attached to the knuckle  111 , which in turn is rotatably coupled to the wheel hub  102 . In this respect, lateral movement of the camber control link  108  pivots the knuckle  111  on the outboard end  110  of the toe control link  106  thereby adjusting the camber. 
     As shown in  FIG. 1 , the chassis module  100 , in one form, may include an exemplary joint  124  between an inboard end  120  of the camber control link  108  and an upper portion  122  of the sub-frame  116 , without any cam mechanism in connection therebetween. In particular, this joint  124  does not include a cam mechanism or a shim mechanism utilized for adjusting or maintaining camber, as the tooling fixture adjusts and maintains the same. The cam mechanisms and shim mechanisms typically include eccentric or lobed washers, which are rotatably carried by bolts and notch-and-key fasteners formed in the outer circumference of the bolts and inner circumference of the washers. In this respect, rotating the bolt fasteners may in turn rotate the washers and engage one or more detents formed on a sub-frame to move the bolt fastener along the slot and thus move the camber control link laterally inward or outward to adjust camber. The joint  124  does not have cam mechanisms, shim mechanisms, eccentric washers, notch-and-key fasteners, and detents on the sub-frame, and thus decreases the cost and weight of the chassis module  100 , while still accurately providing camber that complies within vehicle specifications. 
       FIG. 2  shows an enlarged view of the joint  124  shown in  FIG. 1 . In addition,  FIGS. 3 and 4  illustrate a top elevation view and an enlarged top view, respectively, of the joint  124  shown in  FIG. 2 . The joint  124  may be configured to permit a tooling fixture to selectively move the wheel hub  102  with respect to the sub-frame  116  and adjust camber to comply with specifications associated with the vehicle by the manufacturer. In particular, while adjusting camber, the tooling fixture moves the camber control link  108  laterally inboard or outboard along the axis  136 . In this way, the tooling fixture can move the wheel hub  102  and the camber control link  108  without using any cam mechanism or shim mechanism integrated within the joint  124 . 
       FIG. 5  illustrates a cross-sectional view of one example of the joint  124  of  FIG. 4 , as taken along line  5 - 5 . The joint  124  may include an aperture  126  formed in the inboard end  120  of the camber control link  108 , and elongated slots  132   a ,  132   b  formed in a clevis  121  extending from the upper portion  122  of the sub-frame  116 . A rotational fastener  128  may be received in the aperture  126  and carried by the camber control link  108 . In this way, the rotational fastener  128  may translate along the respective slots  132   a ,  132   b  (best shown in  FIGS. 2 and 4 ) while the tooling fixture tilts the wheel hub  102  and/or the sub-frame  116  toward the predetermined camber angle. As shown in  FIG. 5 , the rotational fastener  128  in this form may be a bolt fastener  130 , pin or any other suitable fastener pivotally attached to the inboard end  120  of the camber control link  108 . In addition, the rotational fastener  128  may include a bushing  131  carried by the bolt fastener  130  within the aperture  126  and the clevis  121 , to facilitate pivoting of the camber control link  108  on the bolt fastener  130 . Further, the rotational fastener  128  may have a nut fastener  134  coupled to the bolt fastener  130  to hold the wheel hub  102  at the predetermined camber. In particular, the bolt fastener  130  and/or the nut fastener  134  may be loaded with a predetermined amount of torque to hold the bolt fastener  130  and camber control link  108  at a fixed point along the slots  132   a ,  132   b , which in turn holds the knuckle  111  and the wheel hub  102  at fixed positions relative to the sub-frame  116  to provide the predetermined camber. 
     In this example, no portion of the joint  124  includes a cam washer, a cam bolt, a cam mechanism, a shim mechanism, notch-and-key fasteners between any washer and bolt, detents formed on the sub-frame for engaging cam washers, or any other cam adjusting mechanisms in connection between the inboard end  120  of the camber control link  108  and the upper portion  122  of the sub-frame  116 . In this respect, the bolt fastener  130  can rotate one or more full turns while the camber control link  108  remains in a fixed position along the slots  132   a ,  132   b . Furthermore, the sub-frame  116  has planar surfaces  133   a ,  133   b  surrounding a respective one of slots  132   a ,  132   b . The bolt fastener  130  has a head portion  135 , which corresponds with the planar surface  133   a  and is configured to rotate at least one full turn across the planar surface  133   a . In this way, the camber control link  108  remains at a fixed position along the slots  132   a ,  132   b  when torque is applied to the nut fastener  134  and/or the head  135  causing the same to spin. Similarly, the nut fastener  134  corresponds with the planar surface  133   b  and is configured to rotate at least one full turn across the planar surface  133   b , such that the camber control link  108  remains at a fixed position along the slots  132   a ,  132   b  when torque is applied to the nut fastener  134  and/or the head  135 . In addition, as shown in  FIG. 5 , the head  135  has an outer diameter surface  137  extending continuously about a circumference of the head, e.g. without notches, splines or keys for attaching to a cam washer. Similarly, the bolt fastener  130  has a shaft  139  that extends from the head  135  and has a threaded profile  141  extending continuously about a circumference of the shaft from one end of the shaft  139  to the other end, e.g. without notches, splines or keys for attaching to a cam washer. 
       FIG. 6  is an enlarged view of an example of a joint  124 ′ between the knuckle  111  and the outboard end  118  of the camber control link  108 . This joint  124 ′ is similar to the joint  124  between the inboard end  120  of camber control link  108  and the sub-frame  116 , with similar components identified by the same reference numerals followed by the prime symbol (′). In particular, no portion of the joint  124 ′ includes a cam washer, a cam bolt, a cam mechanism, a shim mechanism, notch-and-key fasteners between any washer and bolt, detents formed on the sub-frame for engaging cam washers, or any other cam adjusting mechanisms in connection between the camber control link  108  and the knuckle  111 . The joint  124 ′ includes an outboard bolt fastener  130 ′ that can rotate one or more full turns while the camber control link  108  remains in a fixed position. Furthermore, the knuckle  111  has a clevis  121 ′ including a pair of slots  132   a ′,  132   b ′ and planar surfaces  133   a ′,  133   b ′ surrounding a respective one of the slots  132   a ′,  132   b ′. The bolt fastener  130 ′ has a head portion  135 ′, which corresponds with the planar surface  133   a ′ and is configured to rotate at least one full turn across the planar surface  133   a ′, such that the camber control link  108  remains at a fixed position along the slots  132   a ′,  132   b ′ when torque is applied to the nut fastener  134 ′. Similarly, the nut fastener  134 ′ corresponds with the planar surface  133   b ′ and is configured to rotate at least one full turn across the planar surface  133   b ′, such that the camber control link  108  remains at a fixed position along the slots  132   a ′,  132   b ′ when torque is applied to the nut fastener  134 ′. In addition, the head  135 ′ has an outer diameter surface  137 ′ extending continuously about a circumference of the head, e.g., without any notches, splines or keys that could be used to mount a cam washer. Similarly, the bolt fastener  130 ′ has a shaft  139 ′ extending from the head  135 ′ and having a threaded profile  141 ′ that extends continuously about a circumference of the shaft from one end of the shaft  139 ′ to the other end, e.g., without any notches, splines or keys for attaching to a cam washer or other eccentric lobe. 
     Referring to  FIG. 7A , there is illustrated another exemplary joint  724  that is substantially similar to the joint  124  shown in  FIG. 4 , and has substantially similar components identified with corresponding reference numerals in the 700 series. However, the joint  724  in this form may include a clevis  721  extending from the inboard end  720  of a camber control link  708 . The clevis may have elongated slots  732   a ,  732   b , and an upper portion  722  of a sub-frame  716  may have an aperture  726  generally aligned with the slots  732   a ,  732   b . A rotational fastener  728  may be received within the aperture  726  and carried by the sub-frame  716 , such that the rotational fastener  728  may translate along the slots  732   a ,  732   b  while the tooling fixture tilts the wheel hub and/or the sub-frame toward the predetermined camber angle. As with the previous example, the rotational fastener  728  may be a bolt element, pin or any other suitable rotational fastener, and the rotational fastener  728  may include a nut fastener  734  to hold the wheel hub in a position for providing the predetermined camber. The nut fastener  734  may be coupled to the bolt element  730  and loaded with a predetermined amount of torque for holding the rotational fastener  728  in a fixed position within the slots  732   a ,  732   b , and therefore holding the camber control link  708  in a fixed position relative to the sub-frame. As with the previous example, no portion of this joint  724  includes a cam washer, a cam bolt, a cam mechanism, a shim mechanism or any cam adjusting mechanism in connection between the camber control link  708  and the sub-frame  716 . 
     Referring to  FIG. 7B , there is illustrated another exemplary joint  724 ′ that is substantially similar to the joint  124 ′ shown in  FIG. 6 , and has substantially similar components identified with corresponding reference numerals in the 700 series. However, the joint  724 ′ in this form may include a clevis  721 ′ extending from the outboard end  718  of a camber control link  708 . The clevis  721 ′ may include elongated slots  732   a ′,  732   b ′, and an upper portion of the knuckle  711  may include an aperture  726 ′ that is generally aligned with the slots  732   a ′,  732   b ′. A rotational fastener  728 ′ may be received within the aperture  726 ′ and carried by the knuckle  711 , such that the rotational fastener  728 ′ may translate along the slots  732   a ′,  732   b ′ while the tooling fixture tilts the wheel hub and/or the sub-frame toward the predetermined camber angle. Continuing with the previous example, the rotational fastener  728 ′ may be a bolt element, pin or any other suitable rotational fastener, and the rotational fastener  728 ′ may include a nut fastener  734 ′ to hold the wheel hub in a position for providing the predetermined camber. The nut fastener  734 ′ may be coupled to the bolt element  730 ′ and loaded with a predetermined amount of torque for holding the rotational fastener  728 ′ in a fixed position within the slots  732   a ′,  732   b ′, and therefore holding the camber control link  708  in a fixed position relative to the knuckle  711 . As with the previous example, no portion of this joint  724 ′ includes a cam washer, a cam bolt, a cam mechanism, a shim mechanism or any cam adjusting mechanism in connection between the camber control link  708  and the sub-frame  716 . 
     Referring to  FIG. 8 , there is illustrated one exemplary method  800  for adjusting camber of the chassis module  100  shown in  FIG. 1  with reference to components depicted therein. The method may begin at block  802 , in which the chassis module  100  is secured to a tooling fixture. In particular, in one example, a bottom portion  114  of the sub-frame  116  is spaced apart from a lower portion of the wheel hub  102  by the toe control link  106 . The inboard end  112  of the toe control link  106  may be pivotally attached to the bottom portion  114  of the sub-frame  116 . Further, the outboard end  110  of the toe control link  106  may be pivotally attached to the knuckle  111 , which in turn is rotatably coupled to the wheel hub  102 , such that the bottom portion  114  of the sub-frame  116  may be held at a substantially fixed distance from the lower portion of the wheel hub  102 . In this way, the camber control link  108 , which is operably coupled to the wheel hub  102 , may move generally along the axis  136  to in turn pivot the wheel hub  102  relative to the outboard end  110  of the toe control link  106  and adjust the camber of the wheel. For example, this step may be accomplished by securing the sub-frame  116  to a stationary tooling fixture (not shown) and holding the sub-frame  116  in a fixed position, while the camber control link  108  and wheel hub  102  are mounted to a movable portion of the tooling fixture (not shown) or manually moved by an operator. 
     At step  804 , the camber of a wheel may be estimated by measuring camber at the wheel hub  102 , from, for example, a face of the wheel hub  102 . However, the camber may instead be measured with reference to other suitable portions of the chassis module or any combination thereof. The current camber may be used to determine the deviation of the wheel from the predetermined camber angle and, therefore, the amount of adjustment to the chassis module. 
     At step  806 , the wheel hub  102  may be tilted toward a predetermined camber angle. In particular, this step may be accomplished by using the tooling fixture to move the wheel hub  102  and camber control link  108 , without any cam mechanism or shim mechanism at the joint. In this example, the tooling fixture may move the camber control link  108  toward the sub-frame  116  or the wheel hub  102 , so as to pivot the wheel hub  102  toward the predetermined camber angle. Also, the rotational fastener  128  may pivotally carry the inboard end  120  of the camber control link  108 . The camber control link  108  may carry the rotational fastener  128  within the elongated slots  132   a ,  132   b  in the sub-frame  116 , as the camber control link  108  is moved toward the sub-frame  116  or the wheel hub  102 . 
     At step  808 , the wheel hub  102  may be held at the predetermined camber angle by, for example, attaching the rotational fastener  128  at the fixed position along the slots  132   a ,  132   b  in the sub-frame  116 , which in turn holds the camber control link  108  and the wheel hub  102  a fixed position along the axis  136 . This may be accomplished by engaging the nut fastener  134  with the bolt fastener  130  and loading the nut fastener  134  with a predetermined amount of torque to hold the rotational fastener  128  at the fixed point along the slot  132 . This rotational fastener does not include any cam mechanism or shim mechanism. 
     Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope of the invention should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the invention is capable of modification and variation. 
     All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.