Abstract:
A brake system is provided for a straddle-type ATV. The brake system includes a brake caliper configured to mount to a gear box of the ATV and a brake disk configured to connect to a coupling member of the gear box coupled to a shaft and positioned in operative relation relative to the caliper. The brake system additionally includes a brake-actuating control mechanism in communication with the brake caliper. The brake-actuating control mechanism controls the brake caliper to provide selective frictional engagement between the brake caliper and the brake disk.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 60/253,719, filed Nov. 29, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a brake system for a vehicle and, more particularly, to an inboard brake system for a straddle-type all-terrain vehicle.  
           [0004]    2. Description of Related Art  
           [0005]    All-terrain vehicles (ATV&#39;s) generally utilize front and rear brake systems. Prior front brake systems have included disk or drum brake assemblies that are mounted to each front wheel assembly. For example, it is known in the art to mount a brake disk to the hub of each front wheel assembly that is engagable by a brake caliper. Each brake caliper is rigidly mounted to the upright structure of each wheel assembly, and is driven by a hydraulic or cable system that is actuated using a hydraulic or mechanical lever mounted on the handlebars. Additionally, it is known to mount a brake drum to the hub and provide a pair of brake shoes engagable with the brake drum to effect braking. The brake shoes and an actuating mechanism (typically includes a piston and adjuster) are mounted to the upright structure of the wheel assembly within an inner periphery of the brake drum and are non-rotatable relative to the brake drum. Similarly as with disk brakes, drum brakes may be driven by a hydraulic or cable system actuated using a hydraulic or mechanical lever mounted on the handlebars.  
           [0006]    These types of front braking systems provide adequate braking force, but have several disadvantages. For example, mounting the brake assemblies to the front wheel assemblies exposes the components of the brake assemblies, such as the brake disks or drums, calipers, and brake lines, to damage from obstacles such as rocks and other debris. Furthermore, the weight that is carried by the suspension is increased since the entirety of each brake assembly is mounted on the respective wheel assembly. As such, there is more weight on moving parts of the suspension system requiring these parts to be stronger. Strengthening the suspension system generally requires heavier and/or more expensive parts. Furthermore, it may be more difficult to precisely tune or calibrate the suspension system, especially shocks and/or springs, to provide a comfortable ride.  
           [0007]    Prior rear brake systems include those that have been used on ATVs that have chain driven rear axles. These brake systems generally have a single brake disk mounted on the rear axle. These types of brake systems however usually lead to chain stretching, which may cause damaging backlash due to slack in the chain. Upon braking, take-up of slack in the chain causes jarring of the ATV. The jarring can cause fatigue wear of the rear axle components.  
           [0008]    An alternative to this type of rear brake system includes rear disk brake assemblies that are mounted to at least one of the rear wheel assemblies. These systems are applicable to ATVs that have chain-driven or shaft-driven rear axles. However, as with the similar front disk brake systems, these rear disk brake systems are prone to damage from debris and increase the sprung weight of the rear suspension. Furthermore, four wheel drive-type all-terrain vehicles that have these types of brake systems are also subject to damaging backlash within the rear drive assembly, which typically includes a gear box. Backlash is caused when braking power is transferred from, e.g., the rear brakes to the front of the vehicle through the rear drive assembly and drive line. The braking power that is transferred through the rear drive assembly is subject to play between gears within the gear box. When the brakes are engaged, the output of the rear drive assembly effectively slows or stops and the rear drive assembly is jarred as the engine takes up the play within the gearing of the gear box. The jarring can cause excessive wear and fatiguing of the gears and result in damage to the rear drive assembly.  
           [0009]    Another type of rear brake system for an all-terrain vehicle is described in U.S. Pat. No. 5,775,457 that includes a drum brake assembly that is integral with the rear gear box. The drum brake assembly is mounted adjacent the gearing of the gear box and internally of the gear box housing. This type of brake system may decrease backlash somewhat, however is costly to manufacture.  
           [0010]    Further, a rear disk brake system has been used that utilizes a single disk brake assembly that is mounted to the engine/transmission end of the drive shaft connecting the rear drive assembly to the transmission. In this system, the brake disk is mounted to a hub disk that is rotatable with the drive shaft. The caliper is mounted to either the engine or the transmission to be engagable with the brake disk. This system is disadvantageous in that the brake system is exposed to the high heat conditions of the engine and transmission. Prolonged exposure to high heat conditions is detrimental to brake pad and brake disk life and reduces braking effectiveness and efficiency.  
         BRIEF SUMMARY OF PREFERRED EMBODIMENTS  
         [0011]    It is an aspect of the invention to provide a brake system for an ATV that is less prone to damage from obstacles than prior art systems.  
           [0012]    It is another aspect of the invention to provide a brake system for an ATV that reduces weight carried by the suspension relative to prior art systems.  
           [0013]    It is another aspect of the invention to provide a brake system for an ATV that has reduced componentry.  
           [0014]    It is yet another aspect of the invention to provide a brake system for an ATV that reduces backlash within a drive assembly of the ATV.  
           [0015]    According to one preferred embodiment of the present invention, a brake system for a straddle-type ATV is provided that includes a brake caliper configured to mount to a gear box of the ATV and a brake disk configured to connect to a coupling member of the gear box coupled to a shaft and positioned in operative relation relative to the caliper. The brake system also includes a brake-actuating control mechanism in communication with the brake caliper, wherein the brake-actuating control mechanism controls the brake caliper to provide selective frictional engagement between the brake caliper and the brake disk.  
           [0016]    It is an aspect of the invention to provide an ATV with a brake system that is less prone to damage from obstacles than prior art ATVs.  
           [0017]    It is another aspect of the invention to provide an ATV with a brake system that reduces weight carried by the suspension relative to prior art ATVs.  
           [0018]    It is another aspect of the invention to provide an ATV with a brake system that has reduced componentry.  
           [0019]    It is yet another aspect of the invention to provide an ATV with a brake system that reduces backlash within a drive assembly of the ATV.  
           [0020]    According to another preferred embodiment of the present invention, a straddle-type ATV is provided that includes a plurality of wheels, a frame, an engine coupled to the frame and constructed and arranged to provide power to at least one of the plurality of wheels, and a transmission coupled to the engine. The ATV also includes a gear box connected to the frame and in spaced relation to the engine and the transmission, wherein the gear box is operatively connected to the transmission via a driveshaft. The ATV also includes a pair of wheel assemblies that support the plurality of wheels, wherein the wheel assemblies are communicated to the gear box. Furthermore, the ATV includes a brake system that includes a brake caliper configured to mount to the gear box, a brake disk configured to connect to a coupling member of the gear box coupled to a shaft and positioned in operative relation relative to the caliper, and a brake-actuating control mechanism in communication with the brake caliper. The brake-actuating control mechanism controls the brake caliper to provide selective frictional engagement between the brake caliper and the brake disk.  
           [0021]    Those and other aspects, features and advantages of the present invention will become apparent from the following detailed description of the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    [0022]FIG. 1 is a perspective view of a straddle-type all-terrain vehicle (ATV) equipped with a brake system of the present invention;  
         [0023]    [0023]FIG. 2 is a perspective view of a frame in phantom including a brake system of the present invention;  
         [0024]    [0024]FIG. 3 is a detailed perspective view of a first embodiment of the brake system of the present invention;  
         [0025]    [0025]FIG. 4 is a side view of the brake system shown in FIG. 3;  
         [0026]    [0026]FIG. 4A is a sectional view of a portion of the brake system taken along line  4 A- 4 A in FIG. 4;  
         [0027]    [0027]FIG. 5 is a front view of the first embodiment of the brake system shown in FIG. 3;  
         [0028]    [0028]FIG. 6 is an exploded view of the brake system shown in FIG. 5;  
         [0029]    [0029]FIG. 7 is a detailed perspective view of a second embodiment of the present invention;  
         [0030]    [0030]FIG. 8 is a front view of the brake system shown in FIG. 7;  
         [0031]    [0031]FIG. 9 is a side view of the brake system shown in FIG. 8;  
         [0032]    [0032]FIG. 10 is an exploded view of the brake system shown in FIG. 9; and  
         [0033]    [0033]FIG. 11 is a top view of the second embodiment brake system shown in use with a different drive assembly. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0034]    [0034]FIG. 1 shows an all-terrain vehicle (ATV)  10  equipped with a brake system of the present invention. The ATV  10  comprises a frame structure  12 , which extends substantially the entire length of the ATV  10 . A body portion  14  is disposed above and connected to the frame structure  12  and preferably includes a straddle-type seat  16  thereon.  
         [0035]    As shown in FIG. 2, frame structure  12  defines an engine-receiving opening, indicated at  18 , within which a power unit, e.g., an engine (not shown), may be positioned. Preferably, the engine includes an integral transmission or has a transmission operatively coupled thereto (not shown).  
         [0036]    The ATV  10 , shown in FIG. 1, is of a  4 -wheel drive type. Two front and rear brake systems of the present invention are illustrated in FIG. 2 at  30  and  32 , respectively. The brake system  30  is shown installed on a front drive assembly  34  of the ATV  10 , while the brake system  32  is shown installed on a rear drive system  36 . Of course, either embodiment  30 ,  32  of the brake system of the present invention may be used on either of the front and rear drive systems  34 ,  36 , as will be described in further detail below.  
         [0037]    As shown in FIG. 2, the front drive system  34  includes a drive shaft, or propeller shaft,  38 , which is connected to and transfers power between the transmission and a gear box  40 . It is noted that the gear box  40  may be a differential type gear box, which allows relative rotational movement between the wheel assemblies  44 ,  46 . FIG. 2 shows the gear box  40  as a differential type gear box, however, it is, of course, possible for any other type of gear box to be used that is capable of transferring power between the drive shaft  38  and wheel assemblies  44 ,  46 . The gear box  40  is operatively coupled to each hub  42  of front wheel assemblies  44 ,  46  via respective half-shafts  48 ,  50 . The half-shafts  48 ,  50  serve to provide for the transfer of power between the differential  40  and the hubs  42 . It is noted that each half-shaft  48 ,  50  may include one or more universal joints or ball-spline joints, which allow for the transfer of power and movement of the wheel assemblies  44 ,  46 .  
         [0038]    As shown in FIG. 3, the brake system  30  includes a pair of brake disks  52  and a corresponding pair of brake calipers  54 . It is noted that, for a non-differential type gear box, the brake system  30  may include a single brake disk  52  and corresponding brake caliper  54 . However, preferably, when the gear box is a differential type, the brake system  30  includes a pair of brake disks  52  and a corresponding pair of calipers  54 . The brake disks  52  and calipers  54  provide at least some of the braking capability of the ATV  10 . As shown in FIGS.  3 - 6 , each brake disk  52  is fixed to a coupling member  56 , which is communicated with the gear box  40  so as to transfer power from the gear box  40  to the respective half-shaft  48 ,  50 , as will be discussed below. Each coupling member  56  includes a plurality of radially outwardly extending flange elements  58 . Each flange element  58  has a plurality of threaded openings  60  (as shown in FIG. 3), which correspond to a plurality of openings  62  within a plurality of radially inwardly extending connecting portions  63  of the respective brake disk  52 . A plurality of fasteners  64  (see FIG. 6) extend within the openings  62  in the disk  52  and threadedly engage within the threaded openings  60  within the coupling member  56 . It is noted that the fasteners  64  may be threaded fasteners or any other suitable fasteners. Additionally, each disk  52  may be mounted to the coupling member  56  in any other suitable manner, or may be formed integrally with the coupling member  56 . Accordingly, the brake disk  52  may be non-rotatably mounted to respective differential hubs  56  (see FIG. 3). It is contemplated that the brake disk  52  may cooperate with the coupling member  56  and fasteners  64  so as to form a floating-type brake disk configuration. Such a floating type brake disk configuration allows for the expansion of the brake disk caused by heat build-up and may prevent warpage of the disk in high heat situations. It is, of course, also contemplated that the brake disk  52  may be substantially rigidly connected to respective coupling members  56 , i.e. a non-floating disk configuration. In the case wherein the brake disk  52  is mounted in a floating manner, it may be preferable for the caliper  54  to be mounted in a relatively rigid fashion. Alternatively, in the case wherein the brake disk  52  is mounted in a relatively rigid manner, it may be preferably for the caliper  54  to be mounted in a floating fashion.  
         [0039]    Each caliper  54  is coupled to a casing, or housing,  66  of the gear box  40 . Brackets  68  are rigidly connected to respective laterally outwardly facing surfaces  69  of the casing  66  and extend generally radially outwardly from the casing  66 . The bracket  68  may extend radially outwardly from the casing  66  to a point past a radial extent of the brake disk  52 , however, bracket  68  may also be configured such that it does not extend radially past the radial extent of the brake disk  52 . As shown in FIG. 3, each caliper  54  may include laterally outwardly extending leg structures  70  that are connected to the brackets  68 . An outward end of each leg structure  70  includes a post portion  72  that has a fastener receiving opening  74  formed therein. Referring to FIG. 4A, a fastener  76  is disposed within each opening  74  and is threadedly engaged with a threaded opening  78  within the bracket  68 . Accordingly, the calipers  54  are securely connected to respective brackets  68 . As also shown in FIG. 4A, the casing  66  has formed therein a plurality of fastener receiving portions  80  which abut bracket  68  at the outwardly facing surfaces  69  thereof. Each fastener receiving portion  80  includes a threaded opening  82  that threadedly receives a threaded fastener  84 , which extends through an opening  86  in the bracket  68 . Accordingly, the calipers  54  may be connected to the casing  66  via the brackets  68 .  
         [0040]    The illustrated embodiment of the brake system  30  is shown installed on the front drive assembly  34 , which is a gear box and half-shaft type drive assembly. It is noted, however, that the brake system  30  may be installed on either or both of the front drive assembly and rear drive assembly when these drive assemblies are gear box and half-shaft types. As such, the brake system  30  may be used as either a front braking system or a rear braking system. It is also noted that an ATV may be equipped with the brake system  30  on either it&#39;s front or rear drive assemblies or on both.  
         [0041]    [0041]FIG. 3 shows the half-shafts  48 ,  50  and gear box  40  connected with ball-spline joints  51 . In particular, each end of each half-shaft  48 ,  50  is provided with a series of splines (not shown) that are received within respective splined openings (not shown) within the hubs  42 . In this manner, the half-shafts  48 ,  50  are able to transfer power between the gear box  40  and the hubs  42  to affect movement of the ATV. Additionally, the wheel assemblies  44 ,  46  are capable of moving relative to the frame  12  due to the ball-spline joints to allow for suspension travel. In this configuration, the coupling members  56  are axially and radially stationary with respect to the gear box  40  and therefore are axially and radially stationary with respect to the calipers  54 .  
         [0042]    Conversely, it is contemplated that the half-shafts  48 ,  50  may be provided with universal joints to allow for the suspension travel in lieu of the ball-spline joints  51 . For this situation, the coupling members  56  form yokes, which cooperate with corresponding yokes on ends of the half-shafts  48 ,  50 . The brake disks  52  are connected to respective yokes, similarly as shown in FIG. 7 with respect to yoke  116  and brake disk  114 . In this manner, power is transferred between the gear box  40  and the hubs  42  via the half-shafts  48 ,  50  and the universal joints, while allowing for suspension travel of the wheel assemblies  44 ,  46 . In this configuration, the yokes are axially and radially stationary with respect to the gear box  40  and therefore are axially and radially stationary with respect to the calipers  54 .  
         [0043]    As shown in FIG. 6, each of the calipers  54  includes an outer brake pad  204  and an inner brake pad  206 . It is noted that the brake pads  204 ,  206  are preferably formed of a friction material to increase friction (and therefore the braking force) between the brake pads and the associated brake disks. Furthermore, it is preferable of the material of the brake pads to be relatively softer than the material of the brake disks to prevent excessive wear of the brake disks. Each of the outer brake pads  204  is engagable with an associated outwardly facing surface of the respective brake disk  52 . Similarly, each inner brake pad  206  is engagable with an inwardly facing surface of the respective brake disk  52 .  
         [0044]    Each of the half-shafts  48 ,  50  is non-rotatably coupled to the associated hub  42 , therefore is able to transfer a braking force generated by the brake system  30  to the associated hub  42  via the respective half-shafts  48 ,  50 . As such, the ATV  10  may be slowed and/or stopped.  
         [0045]    The brake system  30  is advantageous due to the inboard arrangement of the brake disks  52  and calipers  54 . The components of the brake system (calipers, brake disks, hydraulic lines, etc.) are significantly more protected than prior art systems wherein the components are mounted adjacent the wheel assemblies. The brake system  30  is much less prone to suffer damage from rocks, sticks, and other debris. Furthermore, a skid plate, or protector plate  208  (see FIG. 1) may be fixedly connected to the frame  12  in underlying, or otherwise protecting relation to the brake system  30  to further prevent exposure to possibly damaging objects.  
         [0046]    [0046]FIG. 1 shows a brake-actuating mechanism  350  mounted to a handle bar structure  352  of the ATV  10 . It is noted that the illustrated embodiment  30  of the brake system of the present invention is shown as a hydraulically-actuated brake system. As such, the brake-actuating mechanism  350  may be hydraulically connected to the brake calipers  54  to thereby manipulate each of the brake calipers  54 . Hydraulic lines (in the form of hosing, piping, etc.) extend between each of the brake calipers  54  and the brake-actuating mechanism  350 . The hydraulic lines may be rigid tubing, since the brake calipers  54  and disks  52  are not mounted to (and therefore do not move with) the wheel assemblies  44 ,  46 , as with previous brake systems and therefore the hydraulic lines are not prone to fatigue breakage. The brake-actuating mechanism  350  is constructed and arranged to be manipulable by the user. In the illustrated embodiment, the brake-actuating mechanism  350  includes a lever member  354  that is actuable by the user&#39;s hand. When squeezed, the brake-actuating mechanism  350  delivers a fluid under pressure to each of the brake calipers  54  via the hydraulic lines to thereby engage each of the brake pads with the respective sides of each brake disk. It is also contemplated that the brake system  30  may be cable or linkage-actuated. For example, a sheathed cable (not shown) may extend from the brake-actuating mechanism  350  to each of the brake calipers  54  to allow the user to actuate the calipers  54 . In any case, the brake disks  52  may be effectively “squeezed” between the brake pads when the respective brake calipers  54  are actuated.  
         [0047]    Referring back to FIG. 2, the second embodiment  32  of the brake system of the present invention is shown installed on the rear drive assembly  36  of the ATV  10 . The rear drive assembly  36  includes a gear box,  100 , which is communicated to rear hubs  102  to transfer power thereto via respective half-shafts  104 ,  106 . In this manner, wheel assemblies  108 ,  110  have power provided thereto via the respective half-shafts  104 ,  106 , the gear box  100 , and a drive shaft, or propeller shaft,  112 , which communicates and transfers power between the transmission and gear box  100 . It is noted that the gear box  100  may be of any type including a differential type (which allows relative rotational movement between the wheel assemblies  108 ,  110 ). It is further noted that FIG. 2 shows the gear box  100  as a non-differential type, however, any other type of gear box may be used that is capable of transferring power between the drive shaft  112  and wheel assemblies  108 ,  110 .  
         [0048]    Shown in greater detail in FIG. 7, the brake system  32  includes a brake disk  114  connected to a yoke  116  of a universal joint  118  on a rearward end of the drive shaft  112 . Additionally, the brake system  32  includes a brake caliper  120  relatively fixedly mounted to the gear box  100 . In this manner, the brake system  32  is able to provide at least some of the braking capability of the ATV  10 .  
         [0049]    As shown in FIG. 8, the yoke  116  includes a pair of flange structures  122  that allow for the connection of the brake disk  114  to the yoke  116 . Specifically, the brake disk  114  includes a plurality of radially inwardly extending connecting portions  123  that cooperate with respective outer end portions of the flange structures  122 . As also shown, the caliper  120  is connected to a bracket  124  that extends between and connects the caliper  120  and a casing, or housing,  126  of the gearbox  100 .  
         [0050]    Referring back to FIG. 7, the caliper  120  includes a pair of generally laterally outwardly extending leg structures  128 , which serve to connect the caliper  120  to the bracket  124  via a pair of fasteners  130 , as described with respect to the first embodiment  30  of the brake system of the present invention. Additionally, the bracket  124  is connected to fastener receiving portions  132  (see FIG. 9) provided by an input portion  134  of the gear box  100 , as shown in FIGS. 9 and 10. Fasteners  136  connect the bracket  124  to the fastener receiving portions  132 , similarly as with the first embodiment  30  of the brake system of the present invention. As shown in FIG. 10, the brake disk  114  is connected to the flange structures  122  via respective threaded fasteners  138 .  
         [0051]    It is noted that the brake disk  114  and caliper  120  may be of the floating type, as discussed above with respect to the first embodiment  30  of the brake system of the present invention, to allow for expansion of the brake disk  114  in high heat situations.  
         [0052]    As shown in FIGS. 9 and 10, the caliper  120  includes an outer brake pad  300  and an inner brake pad  302 . It is noted that the brake pads  300 ,  302  are preferably formed of a friction material to increase friction (and therefore the braking force) between the brake pads and the brake disk  114 . Furthermore, it is preferable for the material of the brake pads to be relatively softer than the material of the brake disk to prevent excessive wear of the brake disk. Each of the outer brake pads  300  is engagable with an associated outwardly facing surface of the brake disk  114 . Similarly, each inner brake pad  302  is engagable with an inwardly facing surface of the brake disk  114 .  
         [0053]    As shown in FIG. 2, each of the half-shafts  104 ,  106  is non-rotatably coupled to the associated hub  102 , therefore is able to transfer a braking force generated by the brake system  32  to the associated hub  102  via the respective half-shafts  104 ,  106 . As such, the ATV  10  may be slowed and/or stopped.  
         [0054]    The embodiment  32  of the brake system illustrated in FIG. 2 is shown installed on a gear box and half-shaft type drive assembly. It is noted, however, that the brake system  32  may be used on either or both of a front and rear drive assembly. It is also noted that the brake system  32  is not limited to use with a gear box and half-shaft type drive assembly.  
         [0055]    For example, FIG. 11 shows a drive assembly  150 , which is a substantially rigid single axle type drive assembly. In particular, the drive assembly  150  includes a pair of tubular axle structures  152 ,  154  that are rigidly connected to opposite ends of an integral gear box  156 . The gear box  156  is communicated with wheel assemblies  158 ,  160  via a respective pair of shaft elements  162 ,  164 . An input portion  166  of the gear box  156  provides a flange structure  168 , which is coupled to a caliper  170 . It is noted that the flange structure  168  may be integral with the input portion  166  or that the flange structure  168  may be rigidly connected to the input portion  166  via fasteners, as described above with respect to the embodiments  30 ,  32  of the brake system of the present invention. The caliper  170  is connected to the flange structure  168  with fasteners  172 . A brake disk  174  is connected to a yoke  176  of a universal joint  178  on a rearward end of a drive shaft, or propeller shaft,  180 .  
         [0056]    [0056]FIG. 7 shows the drive shaft  112  communicated to the gear box  100  via a universal joint  118 . The brake disk  114  is connected to the yoke  116  of the universal joint  118  and, therefore rotates with the drive shaft  112 . The driveshaft  112  transfers power between the transmission and the gear box  100 , while the universal joint  118  allows the drive shaft  112  to be disposed at an angle relative to the gear box  100  and transmission, as shown in FIG. 2.  
         [0057]    Similarly, FIG. 11 shows the brake disk  174  connected to the yoke  176  of the drive shaft  180 . In this arrangement, the gear box  156  is moveable relative to the frame  12 , e.g., transmission. The universal joint  178  allows for relative movement between the gear box  156  and the transmission.  
         [0058]    Alternatively, the drive shaft may be coupled to the gear box via a ball-spline joint, similarly as shown in FIG. 3 with respect to the coupling member  56  and brake disk  52 . Similarly as with the universal joints  1   18 ,  178 , the ball-spline joint allows the drive shaft to transfer power between the transmission and the gear box, while allowing the drive shaft to be angled relative to the gear box and transmission or while allowing the gear box to be moved relative to the frame  12 , e.g., transmission.  
         [0059]    It is noted that the brake disks  114 ,  174  are preferably formed of a heat resistant metallic material. It is preferable for the brake pads  300 ,  302  to be formed of a friction material to increase the breaking force between the brake pads  300 ,  302  and the brake disk. It is also preferable for the material of the brake pads  300 ,  302  to be relatively softer than the material of the brake disk. As such, the brake pads  300 ,  302  may absorb a greater amount of wear than the brake disk and may be replaced at relatively less expense, while protecting the brake disk from extensive damage.  
         [0060]    As with the brake system  30  described hereinabove, the disk brake system  32 , in the illustrated embodiment, is hydraulically-actuated. It is contemplated that an additional brake-actuating mechanism  360 , shown in FIG. 1, may be manipulable by the user to thereby engage the brake caliper. It may be preferable, for the brake-actuating mechanism  360  to include a second lever member  362 , similar to the lever member  354 , or a pedal member (not shown) actuable by the user&#39;s foot. In any case, when actuated by the user, the brake-actuating mechanism  360  delivers a volume of fluid under pressure to the brake caliper, which engages the brake pads  300 ,  302  with the associated surfaces of the brake disk effectively “squeezing” the brake disk.  
         [0061]    As the drive shaft and the wheel assemblies  108  and  110  are rotationally synchronous through the gear box, applying a braking force on the drive shaft via the cooperation of the brake caliper and the brake disk, affects the braking of the wheel assemblies  108  and  110 . As such, the user may actuate the brake caliper to slow and/or stop the ATV  10 .  
         [0062]    The embodiment  32  of the brake system of the present invention is advantageous due to the inboard arrangement thereof. Similarly with the first embodiment  30 , the inboard arrangement significantly reduces damage to the brake system  32  caused by rocks, sticks, and other debris while traversing rugged terrain. The disk brake system  32  is especially well protected when a skid plate, or protector plate, (not shown) is fixedly attached to the frame  12  in protecting relation to the disk brake system  32 . Furthermore, this embodiment is advantageous in that a significant reduction of overall weight is reduced by utilizing a singular disk and caliper versus a pair of calipers and disks, as previous systems utilized. The weight on the suspension system is also reduced, allowing for less expensive designs.  
         [0063]    Additionally, torque acting on the drive shaft (and therefore the brake disk) is relatively lower than the torque on the wheel assemblies  108 ,  110 , due to the gearing ratio of the gear box. Consequently, the brake disk and brake caliper may be of relatively smaller size and effectively slow or stop the ATV  10 . The relatively smaller size of the components of the brake system  32  also reduces the overall weight of the ATV and the weight on the suspension system.  
         [0064]    It will be appreciated that numerous modifications to and departures from the preferred embodiments described above will occur to those having skill in the art.