Patent Application
20070187920
The present disclosure relates to methods for connecting suspension and drive train elements for golf car and off-road utility vehicles.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Golf cars and many off-road or utility vehicles, hereinafter “golf cars” commonly have suspension systems requiring multiple components and multiple fasteners for installation. Assembly line construction of golf cars commonly requires multiple installation tools and multiple different supplies of fasteners be present. This can lead to installation of incorrectly sized fasteners or application of insufficient or excessive torque to the fasteners if the wrong fastener or incorrect torque tool is used.
Assembly costs of common golf car designs are therefore limited in part by the quantity of fastener types and torques to be used. Further, visual inspection is often unable to determine if incorrect fasteners or torques are used, leading to potential deficiencies. Use of installation dollies or fixtures to hold components during assembly is also potentially limited due to different access requirements for different sized installation tools.
According to several embodiments of the present disclosure, a method for standardizing fastener installation for a golf car suspension system includes configuring each of a plurality of suspension system component connections as a metal-to-metal contact connection. The method further includes selecting a single fastener engagement size for each of a plurality of fasteners used to couple the component connections. Further, the method includes applying a predetermined torque to the plurality of fasteners, the predetermined torque selected from a predetermined range of torque values. Still further, the method includes installing each of the fasteners using a single installation tool.
According to other embodiments, a method for standardizing fastener installation for a golf car suspension system, the suspension system including a leaf spring and a shock absorber includes configuring each of a plurality of suspension system component connections as one of a plurality of metal-to-metal contact connections. The method also includes selecting a single fastener engagement size for each of a plurality of fasteners used to couple the plurality of component connections. The method further includes sub-assembling the plurality of suspension system component connections prior to torquing any of the plurality of fasteners. The method still further includes applying a single predetermined torque value to each of the plurality of fasteners, the predetermined torque value selected from a range of torque values.
According to still other embodiments, a method for assembling a golf car suspension system, the suspension system having a shoulder bolt having a bolt head, a bolt having a bolt shaft, a leaf spring having a rolled end, a leaf spring link assembly, a shock absorber having a connecting sleeve and an extension sleeve positioned within the connecting sleeve, and a support plate includes installing a plurality of fasteners to operably assemble the golf car suspension system. The method also includes sliding a first fastener defining the shoulder bolt having a starting thread position through the rolled end of the leaf spring. The method further includes connecting a second fastener defining a first nut into engagement with the starting thread position to operably define a first metal-to-metal contact connection. The method still further includes positioning a third fastener defining the bolt with the bolt shaft inserted through the extension sleeve until a bolt engagement face of the bolt contacts a first end of the extension sleeve. The method yet still further includes engaging a second end of the extension sleeve with a frame member to operably create a second metal-to-metal contact connection. The method thereafter includes applying a torque having a single torque value to each of the plurality of fasteners.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is in no way intended to limit the present disclosure, application, or uses. Throughout this specification, like reference numerals will be used to refer to like elements. As referred to herein, the term “golf car” is synonymously used to describe application of the present disclosure to golf cars as well as sport utility vehicles such as modified golf cars, used for example as food and/or beverage cars, golf cars adapted for use as hunting/sporting clays vehicles, golf course maintenance vehicles, and the like.
Referring generally to
Golf car 10 can also include a passenger bench seat 28 and a passenger back support cushion 30. A cover or roof 32 can also be provided which is supported from either body 12 or frame 14 by first and second support members 34, 36. A windscreen or windshield 38 can also be provided which is also supported by each of first and second support members 34, 36. A rear section of roof 32 can be supported by each of a first and a second rear support element 40, 42. Other items provided with golf car 10 include golf bag support equipment, accessory racks or bins, headlights, side rails, fenders, and the like.
Golf car 10 is commonly propelled by a power unit such as an engine or battery/motor system which is commonly provided below and/or behind bench seat 28. Golf car 10 is capable of motion in either of a forward direction “A” or a rearward direction “B”. Each of first and second driven wheels 20, 22 can be commonly supported to frame 14 using rear suspension system 24. Each of first and second steerable wheels 16, 18 can be independently or commonly supported to frame 14, therefore the present disclosure is not limited by the design of front suspension system 23.
As best seen in reference to
First and second leaf springs 48, 50 can be connected at a rearward facing end to first and second frame members 44, 46 by each of a first and second link assembly 59, 60. In addition, first and second leaf springs 48, 50 can be connected at a forward facing end to first and second frame members 44, 46 by each of a first and second bracket assembly 62, 64. The use of first and second leaf springs 48, 50 further helps reduce deflection of the rear suspension system 24 in either of a first or second deflection direction “C” or “D”.
Referring now to
According to several embodiments, rear suspension system 24 can further include a first shock absorber 72 and a second shock absorber 74. First shock absorber 72 can include a first connecting sleeve 76 which is fastened using a fastener 78 to a first frame extension 80. First frame extension 80 is a structural element which can be fixedly connected to first frame member 44 for example by welding. Similarly, second shock absorber 74 can include a first connecting sleeve 82 which is connected using a fastener 84 to a second frame extension 86 similar in design to first frame extension 80 but fixedly connected to second frame member 46. For installation of both first and second connecting sleeves 76, 82, a nut 88 such as a weld nut can be fixedly connected to both first and second frame extensions 80, 86 to engage fasteners 78 and 84. First shock absorber 72 can further include a second connecting sleeve 90 which is connected using a fastener 92 to first connecting member 94. Similarly, second shock absorber 74 can include a second connecting sleeve 96 connected by a fastener 98 to second connecting member 100.
First connecting member 94 can be positioned between first housing portion 66 and a first support plate 102. First leaf spring 48 is sandwiched between first support plate 102 and first connecting member 94 using a first U-shaped bolt 104. Similarly, second connecting member 100 can be positioned between second housing portion 68 and a second support plate 106. Second leaf spring 50 is sandwiched between second connecting member 100, and second support plate 106 using a second U-shaped bolt 108.
Each of the first and second leaf springs 48, 50 can be connected to respective ones of first and second frame members 44, 46 using first and second bracket assemblies 62, 64. First and second bracket assemblies 62, 64 can be welded to fixedly connect to the first or second frame member 44, 46. A first shoulder bolt fastener 110 is inserted through opposed walls of the first bracket assembly 62 and a rolled forward end 112 of first leaf spring 48. Similarly, a second shoulder bolt fastener 114 is inserted through opposed walls of the second bracket assembly 64 and a rolled forward end 116 of second leaf spring 50.
As previously noted first and second link assemblies 59, 60 connect the rear portions of first and second leaf springs 48, 50 to first and second frame members 44, 46. Each of the first and second link assemblies 59, 60 include a first shackle plate or first link 118 and a second shackle plate or second link 120, both connected to a first flange member 122 outwardly fixedly connected to first and second frame members 44, 46 and a second flange member 124 inwardly fixedly connected to first and second frame members 44, 46. A first and second shoulder bolt fastener 126, 128 are inserted through first link 118, first flange member 122, a spacing sleeve 134, and second link 120 of each of first and second link assemblies 59, 60. A third and fourth shoulder bolt fastener 130, 132 are inserted through first link 118, a rolled end 136 or 138 of first or second leaf springs 48, 50, and through second link 120. A plurality of washers/bushings 140 made of a low coefficient-of-friction polymeric material such as a polyamide material can be inserted between first or second links 118, 120 and first or second flange members 124, between first or second flange members 124 and spacing sleeves 134, or between first or second links 118, 120 and rolled ends 136, 138 to reduce friction at these locations. A nut 142 such as a weld nut, standard nut, or friction nut can be used for installation of the various shoulder bolts. For consistency, nuts used for the present disclosure are hereinafter referred to as weld nuts.
Shoulder bolts are used for shoulder bolt fasteners 110, 114, first and second shoulder bolt fasteners 126, 128, and third and fourth shoulder bolt fasteners 130, 132 for several reasons. Shoulder bolts define a pre-determined length of bolt shaft before the start of a thread end. The pre-determined length of bolt shaft fixes a spacing width of first and second bracket assemblies 62, 64 and first and second link assemblies 59, 60. The start of the thread end also defines a metal-to-metal contact connection between a nut used at the ends of these fasteners and the bolt shaft when connecting the nut to the appropriate first or second flange member 122, 124 or first or second link 118, 120. In several embodiments, an installation torque range of approximately 20 to 25 lb-ft (27.12 to 33.89 Nm) can be applied to the shoulder bolt fasteners while preventing the crushing of polymeric washers/bushings 140.
First and second leaf springs 48, 50 help limit the vertical deflection of axle housing 56. First and second shock absorbers 72, 74 dampen the vertical travel of axle housing 56 and provide a positive stop for the vertical travel. First and second connecting members 94, 100, function in part to provide an engagement area for first or second leaf springs 48, 50 to contact axle housing 56, and to provide for connection of first and second shock absorbers 72, 74.
Referring now generally to
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Use of a predetermined range of torque values also permits all of the components of rear suspension system 24 to be sub-assembled and/or connected to frame 14 prior to applying the desired torque. This permits a “loose assembly” of components and therefore some reorientation as necessary as the various components are added to the suspension system. Variations between suspension systems due to variations in frame geometry, part variability, installation tolerances, and the like can therefore be accommodated and wheel alignment maintained before the fasteners of the sub-assembled suspension system are torqued.
Metal-to-metal contact connections are established during installation of all the fasteners of the present disclosure. A torque value selected from a predetermined torque range for all the fasteners of the present disclosure can therefore be used. In some embodiments, this torque range is between and inclusive of 20 to 25 lb-ft (27.12 to 33.89 Nm), however the disclosure is not limited to this range, and either lower or higher torque values can be used. In addition, the same engagement size for each fastener head or nut is also selected for all fasteners and nuts of the present disclosure. According to several embodiments, a 15 mm fastener head and nut size is selected, however the disclosure is not limited to this size. By using a standard torque range and common fastener head and nut engagement sizes, all the fasteners of the present disclosure can be installed with the same installation tool, reducing the possibility of installing any fastener or nut to an insufficient torque, over-torquing the fastener or nut and crushing the polymeric washers, or installing an incorrectly sized fastener or nut. Assembly time can therefore be reduced, thereby reducing assembly costs. Further, subsequent maintenance is also simplified as the mechanic does not have to change torque settings or stock multiple fastener sizes to remove or replace suspension components.
The description herein is merely exemplary in nature and, thus, variations that do not depart from the gist of that which is described are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.
